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Title:  Methods of diagnosing and treating small intestinal bacterial overgrowth (SIBO) and SIBO-related conditions
United States Patent: 
7,048,906
Issued: 
May 23, 2006

Inventors:
 Lin; Henry C. (Manhattan Beach, CA); Pimentel; Mark (Los Angeles, CA)
Assignee:
Cedars-Sinai Medical Center (Los Angeles, CA)
Appl. No.:  837797
Filed: 
April 17, 2001


 

Outsourcing Guide


Abstract

Disclosed is a method of treating small intestinal bacterial overgrowth (SIBO) or a SIBO-caused condition in a human subject. SIBO-caused conditions include irritable bowel syndrome, fibromyalgia, chronic pelvic pain syndrome, chronic fatigue syndrome, depression, impaired mentation, impaired memory, halitosis, tinnitus, sugar craving, autism, attention deficit/hyperactivity disorder, drug sensitivity, an autoimmune disease, and Crohn's disease. Also disclosed are a method of screening for the abnormally likely presence of SIBO in a human subject and a method of detecting SIBO in a human subject. A method of determining the relative severity of SIBO or a SIBO-caused condition in a human subject, in whom small intestinal bacterial overgrowth (SIBO) has been detected, is also disclosed.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention is directed to a method of treating small intestinal bacterial overgrowth (SIBO) or a SIBO-caused condition in a human subject, including a juvenile or adult, of any age or sex.

The upper gastrointestinal tract of a human subject includes the entire alimentary canal, except the cecum, colon, rectum, and anus. While some digestive processes, such as starch hydrolysis, begin in the mouth and esophagus, of particular importance as sites of digestion are the stomach and small intestine (or "small bowel"). The small intestine includes the duodenum, jejunum, and the ileum. As the term is commonly used in the art, the proximal segment of the small bowel, or proximal gut, comprises approximately the first half of the small intestine from the pylorus to the mid-gut. The distal segment, or distal gut includes approximately the second half, from the mid-gut to the ileal-cecal valve.

As used herein, "digestion" encompasses the process of breaking down large biological molecules into their smaller component molecules, for example, proteins into amino acids. "Predigested" means that the process of digestion has already begun or has occurred prior to arrival in the upper gastrointestinal tract.

As used herein, "absorption" encompasses the transport of a substance from the intestinal lumen through the barrier of the mucosal epithelial cells into the blood and/or lymphatic systems.

Small intestinal bacterial overgrowth (SIBO), is an abnormal condition in which aerobic and anaerobic enteric bacteria from the colon proliferate in the small intestine, which is normally relatively free of bacterial contamination. SIBO is defined as greater than 10.sup.6 CFU/mL small intestinal effluent. (R. M. Donaldson, Jr., Normal bacterial populations of the intestine and their relation to intestinal function, N. Engl. J. Med. 270:938 45 [1964]).

Typically, the symptoms of SIBO include abdominal pain, bloating, gas and alteration in bowel habits, such as constipation and diarrhea. SIBO-caused conditions is used herein interchangeably with the term "SIBO-related conditions," and regardless of ultimate causation, is a condition associated with the presence of SIBO in the subject. SIBO-caused conditions include other common symptoms, such as halitosis ("bad breath"), tinnitus (the experience of noise in the ears, such as ringing, buzzing, roaring, or clicking, which may not be associated with externally produced sounds), sugar craving, i.e., an intense desire for sweet foods or flavors, which can result in abnormally large consumption of sweet foods and beverages and frequently leads to health-threatening obesity. Drug sensitivity is another common SIBO-caused condition, in which the subject is hypersensitive to medications, such as non-steroidal anti-inflammatory medications, anti-insomniacs, antibiotics, or analgesics, and can suffer an unpredictable allergic-type reaction to medications at doses that normally do not adversely affect the vast majority of patients. It is a benefit provided by the present invention that it provides a useful solution in the present tense, for many patients, to the problem of drug sensitivity, without requiring complex pharmacogenetic research and customized drug development.

Other SIBO-caused conditions, as described herein, can include those falling in the diagnostic categories of irritable bowel syndrome, Crohn's disease, fibromyalgia, chronic pelvic pain syndrome, chronic fatigue syndrome, depression, impaired mentation (including impairment of the ability to concentrate, calculate, compose, reason, and/or use foresight or deliberate judgment), impaired memory, autism, attention deficit/hyperactivity disorder, and/or autoimmune diseases, such as systemic lupus erythematosus (SLE) or multiple sclerosis (MS).

In accordance with the invention, the SIBO-caused condition can be, but need not be, previously diagnosed or suspected. The skilled medical practitioner is aware of suitable up-to-date diagnostic criteria by which a suspected diagnosis is reached. These diagnostic criteria are based on a presentation of symptom(s) by a human subject. For example, these criteria include, but are not limited to, the Rome criteria for IBS (W. G. Thompson, Irritable bowel syndrome: pathogenesis and management, Lancet 341:1569 72 [1993]) and the criteria for CFS established by the Centers for Disease Control and Prevention (CDC). (K. Fukuda et al., The chronic fatigue syndrome: a comprehensive approach to its definition and study, Ann. Intern. Med. 121:953 59 [1994]). The diagnostic criteria for fibromyalgia of the American College of Rheumatology will also be familiar (F. Wolfe et al., The American College of Rheumatology 1990 Criteria for the Classification of Fibromyalgia: Report of the Multicenter Criteria Committee, Arthritis Rheum. 33:160 72 [1990]), as will be the criteria for depression or ADHD provided for example, by the Diagnostic and Statistical Manual (DSM)-IV or its current version. (E.g., G. Tripp et al., DSM-IV and ICD-10: a comparison of the correlates of ADHD and hyperkinetic disorder, J. Am. Acad. Child Adolesc. Psychiatry 38(2):156 64 [1999]). Symptoms of systemic lupus erythematosus include the 11 revised criteria of the American College of Rheumatology, such as a typical malar or discoid rash, photosensitivity, oral ulcers, arthritis, serositis, or disorders of blood, kidney or nervous system. (E. M Tan et al., The 1982 revised criteria for the classification of systemic lupus erythematosus [SLE], Arthritis Rheum. 25:1271 77 [1982]). Appropriate diagnostic criteria for multiple sclerosis are also familiar (e.g., L. A. Rolak, The diagnosis of multiple sclerosis, Neuronal Clin. 14(1):27 43 [1996]), as are symptoms of Crohn's disease useful in reaching a suspected diagnosis. (e.g., J. M. Bozdech and R. G. Farmer, Diagnosis of Crohn's disease, Hepatogastroenterol. 37(1):8 17 [1990]; M. Tanaka and R. H. Riddell, The pathological diagnosis and differential diagnosis of Crohn's disease, Hepatogastroenterol. 37(1):18 31 [1990]; A. B. Price and B. C. Morson, Inflammatory bowel disease: the surgical pathology of Crohn's disease and ulcerative colitis, Hum. Pathol. 6(1):7 29 [1975]). The practitioner is, of course not limited to these illustrative examples for diagnostic criteria, but should use criteria that are current in the art.

Detection of the presence of SIBO in the human subject also corroborates the suspected diagnosis of the SIBO-caused condition, held by a qualified medical practitioner who, prior to the detection of SIBO in the human subject, suspects from more limited clinical evidence that the human subject has, for example, irritable bowel syndrome, fibromyalgia, chronic fatigue syndrome, chronic pelvic pain syndrome, depression, autism, ADHD, an autoimmune disease, or Crohn's disease. By applying the inventive diagnostic method the suspected diagnosis is corroborated, i.e., confirmed, sustained, substantiated, supported, evidenced, strengthened, affirmed or made more firm.

The inventive method of treating SIBO, or a SIBO-caused condition, involves first detecting the presence or absence of SIBO in the subject by suitable detection means. Detecting the presence or absence of SIBO is accomplished by any suitable means or method known in the art. For example, one preferred method of detecting SIBO is breath hydrogen testing. (E.g., P. Kerlin and L. Wong, Breath hydrogen testing in bacterial overgrowth of the small intestine, Gastroenterol. 95(4):982 88 [1988]; A. Strocchi et al., Detection of malabsorption of low doses of carbohydrate: accuracy of various breath H.sub.2 criteria, Gastroenterol. 105(5):1404 1410 [1993]; D. de Boissieu et al., [1996]; P. J. Lewindon et al., Bowel dysfunction in cystic fibrosis: importance of breath testing, J. Paedatr. Child Health 34(1):79 82 [1998]). Breath hydrogen or breath methane tests are based on the fact that many obligately or facultatively fermentative bacteria found in the gastrointestinal tract produce detectable quantities of hydrogen or methane gas as fermentation products from a substrate consumed by the host, under certain circumstances. Substrates include sugars such as lactulose, xylose, lactose, sucrose, or glucose. The hydrogen or methane produced in the small intestine then enters the blood stream of the host and are gradually exhaled.

Typically, after an overnight fast, the patient swallows a controlled quantity of a sugar, such as lactulose, xylose, lactose, or glucose, and breath samples are taken at frequent time intervals, typically every 10 to 15 minutes for a two- to four-hour period. Samples are analyzed by gas chromatography or by other suitable techniques, singly or in combination. Plots of breath hydrogen in patients with SIBO typically show a double peak, i.e., a smaller early hydrogen peak followed by a larger hydrogen peak, but a single hydrogen peak is also a useful indicator of SIBO, if peak breath hydrogen exceeds the normal range of hydrogen for a particular testing protocol. (See, G. Mastropaolo and W. D. Rees, Evaluation of the hydrogen breath test in man: definition and elimination of the early hydrogen peak, Gut 28(6):721 25 [1987]).

A variable fraction of the population fails to exhale appreciable hydrogen gas during intestinal fermentation of lactulose; the intestinal microflora of these individuals instead produce more methane. (G. Corazza et al., Prevalence and consistency of low breath H.sub.2 excretion following lactulose ingestion. Possible implications for the clinical use of the H.sub.2 breath test, Dig. Dis. Sci. 38(11):2010 16 [1993]; S. M. Riordan et al., The lactulose breath hydrogen test and small intestinal bacterial overgrowth, Am. J. Gastroentrol. 91(9); 1795 1803 [1996]). Consequently, in the event of an initial negative result for breath hydrogen, or as a precaution, methane and/or carbon dioxide contents in each breath sample are optionally measured, as well as hydrogen, or a substrate other than lactulose is optionally used. Also, acting as a check, the presence of SIBO is demonstrated by a relative decrease in peak hydrogen exhalation values for an individual subject after antimicrobial treatment, in accordance with the present invention, compared to pretreatment values.

Another preferred method of detecting bacterial overgrowth is by gas chromatography with mass spectrometry and/or radiation detection to measure breath emissions of isotope-labeled carbon dioxide, methane, or hydrogen, after administering an isotope-labeled substrate that is metabolizable by gastrointestinal bacteria but poorly digestible by the human host, such as lactulose, xylose, mannitol, or urea. (E.g., G. R. Swart and J. W. van den Berg, .sup.13C breath test in gastrointestinal practice, Scand. J. Gastroenterol. [Suppl.] 225:13 18 [1998]; S. F. Dellert et al, The 13C-xylose breath test for the diagnosis of small bowel bacterial overgrowth in children, J. Pediatr. Gastroenterol. Nutr. 25(2):153 58 [1997]; C. E. King and P. P. Toskes, Breath tests in the diagnosis of small intestinal bacterial overgrowth, Crit. Rev. Lab. Sci. 21(3):269 81 [1984]). A poorly digestible substrate is one for which there is a relative or absolute lack of capacity in a human for absorption thereof or for enzymatic degradation or catabolism thereof.

Suitable isotopic labels include .sup.13C or .sup.14C. For measuring methane or carbon dioxide, suitable isotopic labels can also include .sup.2H and .sup.3H or .sup.17O and .sup.18O, as long as the substrate is synthesized with the isotopic label placed in a metabolically suitable location in the structure of the substrate, i.e., a location where enzymatic biodegradation by intestinal microflora results in the isotopic label being sequestered in the gaseous product. If the isotopic label selected is a radioisotope, such as .sup.14C, .sup.3H, or .sup.15O, breath samples can be analyzed by gas chromatography with suitable radiation detection means. (E.g., C. S. Chang et al., Increased accuracy of the carbon-14 D-xylose breath test in detecting small-intestinal bacterial overgrowth by correction with the gastric emptying rate, Eur. J. Nucl. Med. 22(10):1118 22 [1995]; C. E. King and P. P. Toskes, Comparison of the 1-gram [.sup.14C]xylose, 10-gram lactulose-H.sub.2, and 80-gram glucose-H.sub.2 breath tests in patients with small intestine bacterial overgrowth, Gastroenterol. 91(6):1447 51 [1986]; A. Schneider et al., Value of the .sup.14C-D-xylose breath test in patients with intestinal bacterial overgrowth, Digestion 32(2):86 91 [1985]).

Another preferred method of detecting small intestinal bacterial overgrowth is direct intestinal sampling from the human subject. Direct sampling is done by intubation followed by scrape, biopsy, or aspiration of the contents of the intestinal lumen, including the lumen of the duodenum, jejunum, or ileum. The sampling is of any of the contents of the intestinal lumen including material of a cellular, fluid, fecal, or gaseous nature, or sampling is of the lumenal wall itself. Analysis of the sample to detect bacterial overgrowth is by conventional microbiological techniques including microscopy, culturing, and/or cell numeration techniques.

Another preferred method of detecting small intestinal bacterial overgrowth is by endoscopic visual inspection of the wall of the duodenum, jejunum, and/or ileum.

The preceding are merely illustrative and non-exhaustive examples of methods for detecting small intestinal bacterial overgrowth.

Another suitable, and most preferred, means for detecting the presence or absence of SIBO is the present inventive method of detecting small intestinal bacterial overgrowth in a human subject, which involves detecting the relative amounts of methane, hydrogen, and at least one sulfur-containing gas in a gas mixture exhaled by said human subject, after the subject has ingested a controlled quantity of a substrate. The inventive method of detecting small intestinal bacterial overgrowth is more likely than conventional breath tests described above to detect the presence of SIBO, because in some subjects a pattern exists that is termed "non-hydrogen, non-methane excretion" (see, e.g., Example 9c hereinbelow). This pattern is the result of the subject having a bacterial population constituting the SIBO condition, in which a sulfate-reducing metabolic pathway predominates as the primary means for the disposition of dihydrogen. In that condition, the removal of the hydrogen can be so complete that there is little residual hydrogen or methane gas to be detected in the exhaled breath, compared to the amount of sulfur-containing gas, such as hydrogen sulfide or a volatile sulfhydryl compound detectable by the inventive method of detecting small intestinal bacterial overgrowth.

In accordance with the inventive method of detecting small intestinal bacterial overgrowth, the substrate is preferably a sugar, as described hereinabove, and more preferably a poorly digestible sugar or an isotope-labeled sugar. The at least one sulfur-containing gas is methanethiol, dimethylsulfide, dimethyl disulfide, an allyl methyl sulfide, an allyl methyl sulfide, an allyl methyl disulfide, an allyl disulfide, an allyl mercaptan, or a methylmercaptan. Most preferably, the sulfur-containing gas is hydrogen sulfide or a sulfhydryl compound.

The detection or determination of the relative amounts of methane, hydrogen, and at least one sulfur-containing gas in the exhaled gas mixture is accomplished by means or systems known in the art, preferably by means of gas chromatography (e.g., Brunette, D. M. et al., The effects of dentrifrice systems on oral malodor, J Clin Dent. 9:76 82 [1998]; Tangerman, A. et al., A new sensitive assay for measuring volatile sulphur compounds in human breath by Tenax trapping and gas chromatography and its application in liver cirrhosis, Clin Chim Acta 1983;May 9; 130(1):103 110 [1983]) and/or a radiation detection system, if appropriate. Most preferably, mass spectrometry is employed to detect the relative amounts of methane, hydrogen, and at least one sulfur-containing gas in the exhaled gas mixture. (E.g., Spanel P, Smith D., Quantification of hydrogen sulphide in humid air by selected ion flow tube mass spectrometry, Rapid Commun Mass Spectrom 14(13):1136 1140 [2000]). Combined gas chromatography and mass spectrometry (GC/MS) is also useful. (E.g., Chinivasagam, H. N. et al., Volatile components associated with bacterial spoilage of tropical prawns, Int J Food Microbiol 1998 June 30,42(1 2):45 55). Most preferably, but not necessarily, the detection system employed requires only a single sample of exhaled gas mixture for the detection of methane, hydrogen, and at least one sulfur-containing gas. Detection methods that separately detect methane, hydrogen, and/or at least one sulfur containing gas are also useful.

Thus, thin-layer chromatography or high pressure liquid chromatography can be useful for detection of volatile sulfur-containing compounds. (E.g., Tsiagbe, V. K. et al., Identification of volatile sulfur derivatives released from feathers of chicks fed diets with various levels of sulfur-containing amino acids, J Nutr 1987 117(11):18859 65 [1987]).

Direct-reading monitors for sulfides based on the use of an electrochemical voltametric sensor or polarographic cell can also be employed. Typically, gas is drawn into a sensor equipped with an electrocatalytic sensing electrode. An electrical current is generated by an electrochemical reaction proportional to the concentration of the gas. The quantity of the gas is typically determined by comparing to a known standard.

In some embodiments of the inventive method of detecting SIBO in a human subject, before detection, volatile sulfur-containing gases are trapped in Tenax absorbent (e.g., Tangerman, A. et al., Clin Chim Acta May 9; 130(1):103 110 [1983]; Heida, H. et al., Occupational exposure and indoor air quality monitoring in a composting facility, Am Ind Hyg Assoc J 56(1):39 43 [1995]) or other solvent/absorbent system such as dinitrophenyl thioethers (Tsiagbe, V. K. et al. [1987]).

It generally takes about 2 to 3 hours of the subjects's time and a pre-test fast to accomplish breath testing for SIBO; thus, a quicker and more convenient screening method to determine those subjects most likely to have SIBO is desirable. Such a screening test allows the clinician to make a more informed decision as to which patients would likely benefit from more definitive SIBO testing, as described above. This pre-screening reduces unnecessary inconvenience and expense for subjects who are unlikely to have SIBO.

Hence, the present invention provides a method of screening for the abnormally likely presence of SIBO in a human subject. By abnormally likely is meant a likelihood of SIBO greater than expected in the general population. The inventive screening method involves obtaining a serum sample from the subject, which conventionally involves a blood draw, followed by separation of the serum from the whole blood. Conventional immunochemical techniques, such as ELISA, employing commercially available reagents, are used to quantitatively determine a concentration in the serum sample of serotonin (5-HT), one or more unconjugated bile acids (e.g., total bile acids or individual bile acids, e.g., deoxycholic acid), and/or folate, an abnormally elevated serum concentration of one or more of these being indicative of a higher than normal probability that SIBO is present in the subject. Such quantitative immunochemical determinations of serum values are also made commercially (e.g., Quest Diagnostics-Nichols Institute, 33608 Ortega Highway, San Juan Capistrano, Calif. 92690).

For example, a normal range for serum 5-HT is up to about 0.5 nanograms per milliliter. The normal range for total bile acids in serum is about 4.0 to about 19.0 micromole per liter, and for deoxycholic acid the normal range is about 0.7 to about 7.7 micromoles per liter. Normal ranges for other unconjugated bile acids are also known. The normal range for serum folate is about 2.6 to about 20.0 nanograms per milliliter. In accordance with the inventive method of screening, subjects with at least one serum value beyond the normal range are thus more than normally likely to have SIBO present and are candidates for further diagnostic SIBO detection procedures.

The present invention also relates to a method of determining the relative severity of SIBO or a SIBO-caused condition in a human subject in whom SIBO has been detected by a suitable detection means, as described herein above. If the presence of SIBO is detected in the subject, then suitable detection means are employed to detect in the subject a relative level of intestinal permeability, compared to normal. Abnormally high intestinal permeability indicates a relatively severe SIBO or SIBO-caused condition in the subject, which alerts the clinician that a more aggressive SIBO treatment regimen is desirable.

Techniques for detecting intestinal permeability and normal intestinal permeability ranges are known. (E.g., Haase, A. M. et al., Dual sugar permeability testing in diarrheal disase, J. Pediatr. 136(2):232 37 [2000]; Spiller, R. C. et al., Increased rectal mucosal endocrine cells, T lymphocytes, and increased gut permeability following acute Campylobacter enteritis and in post dysenteric irritable bowel syndrome, Gut 47(6):804 11 [2000]; Smecuol, E. et al., Sugar tests detect celiac disease among first-degree relatives, Am. J. Gastroenterol. 94(12):3547 52 [1999]; Cox, M. A. et al., Measurement of small intestinal permeability markers, lactulose and mannitol in serum: results in celiac disease, Dig. Dis. Sci. 44(2):402 06 [1999]; Cox, M. A. et al., Analytical method for the quantitation of mannitol and disaccharides in serum: a potentially useful technique in measuring small intestinal permeability in vivo, Clin. Chim. Acta 263(2):197 205 [1997]; Fleming, S. C. et al., Measurement of sugar probes in serum: an alternative to urine measurement in intestinal permeability testing, Clin. Chem. 42(3):445 48 [1996]).

Briefly, intestinal permeability is typically accomplished by measuring the relative serum or urine levels of two sugars, after ingestion of controlled amounts by the subject. One of the sugars, for example mannitol, is chosen because it is more typically more easily absorbed through the intestinal mucosa than the other sugar, for example, lactulose. Then about two hours after ingestion, a serum or urine sample is taken, and the ratio of the two sugars is determined. The closer the ratio of the two sugars in the sample approaches the ratio originally ingested, the more permeable is the subject's intestine.

After the presence of SIBO has been detected in the subject, in accordance with the inventive method of treating small intestinal bacterial overgrowth (SIBO) or a SIBO-caused condition in a human subject, the proliferating bacterial population constituting the SIBO is deprived of nutrient(s) sufficiently to inhibit the growth of the bacteria in the small intestine, which results in at least partially eradicating SIBO in the human subject.

Depriving the bacterial population of nutrient(s) is accomplished by any of a number of means.

For example, in some embodiments of the method of treating SIBO or a SIBO-caused condition, the subject consumes for a sustained period, a diet consisting essentially of nutrients that upon arrival in the upper gastrointestinal tract of the subject, are at least partially predigested. The sustained period being sufficient to at least partially eradicate SIBO in the human subject is at least about three days, preferably about 7 to about 18 days, and more preferably about 10 to about 14 days.

In some embodiments of the method, the at least partially predigested nutrient(s) are contained in a commestible total enteral nutrition (TEN) formulation, which is also called an "elemental diet." Such formulations are commercially available, for example, Vivonex.RTM. T.E.N. (Sandoz Nutrition, Minneapolis, Minn.) and its variants, or the like. (See, e.g., Example 11 hereinbelow). A useful total enteral nutrition formulation satisfies all the subject's nutritional requirements, containing free amino acids, carbohydrates, lipids, and all essential vitamins and minerals, but in a form that is readily absorbable in the upper gastrointestinal tract, thus depriving or "starving" the bacterial population constituting the SIBO of nutrients of at least some of the nutrients they previously used for proliferating. Thus, bacterial growth in the small intestine is inhibited.

In another embodiment of the inventive method, a pancreatic enzyme supplement is administered to the subject before or substantially simultaneously with a meal, such that nutrients contained in the meal are at least partially predigested upon arrival in the upper gastrointestinal tract of the subject by the activity of the pancreatic enzyme supplement. Useful pancreatic enzyme supplements are commercially available, commonly called "Pancreatin"; such supplements contain amylase, lipase, and/or protease. Representative methods of administering the pancreatic enzyme supplement include giving, providing, feeding or force-feeding, dispensing, inserting, injecting, infusing, prescribing, furnishing, treating with, taking, swallowing, ingesting, eating or applying.

In a preferred embodiment, depending on the formulation, the pancreatic enzyme supplement is administered up to a period of 24 hours prior to ingestion of the food or nutrient comprising the meal, but most preferably between about 60 to 0 minutes before ingestion, which is substantially simultaneosly with the meal. The period of time prior to ingestion is determined on the precise formulation of the composition. For example, a controlled release formulation can be administered longer before the meal. Other quick release formulations can be taken substantially simultaneously with the meal.

In other embodiments of the method of treating small intestinal bacterial overgrowth or a SIBO-caused condition, depriving the bacterial population of nutrient(s) involves enhancing the digestion and/or absorption of the nutrient(s) in the upper gastrointestinal tract of the human subject by slowing transit of the nutrient(s) across the upper gastrointestinal tract of the human subject, thereby at least partially depriving the bacterial population of the nutrient(s). These embodiments of the inventive take advantage of a novel understanding of the peripheral neural connections that exist between the enteric nervous system of the upper gastrointestinal tract, including an intrinsic serotonergic neural pathway, and the vertebral ganglia, and thence to the central nervous system. The present invention provides a means to enhance region-to region (e.g., intestino-intestinal reflex) communications by way of replicating 5-HT as a signal (or releasing 5-HT at a distance as a surrogate signal). Thus, the present invention provides a way to increase 5-HT in locations in the central nervous by transmitting a neural signal from the gut, or to transmit a 5-HT-mediated neural signal originating in one location in the gut via an intrinsic cholinergic afferent neural pathway to a second distant location in the gut where a serotonergic signal of the same or greater intensity is replicated.

The present technology, therefore, allows neurally mediated modulation of the rate of upper gastrointestinal transit in the human subject. The present invention allows the artificially directed transmission and/or amplification of nervous signals from one location in the enteric nervous system to another via a prevertebral ganglion, bypassing the central nervous system. The invention takes advantage of an intrinsic serotonergic neural pathway involving an intrinsic cholinergic afferent neural pathway that projects from peptide YY-sensitive primary sensory neurons in the intestinal wall to the prevertebral celiac ganglion. The prevertebral celiac ganglion is in turn linked by multiple prevertebral ganglionic pathways to the central nervous system, to the superior mesenteric ganglion, to the inferior mesenteric ganglion, and also back to the enteric nervous system via an adrenergic efferent neural pathway that projects from the prevertebral celiac ganglion to one or more enterochromaffincells in the intestinal mucosa and to serotonergic interneurons that are, in turn, linked in the myenteric plexus or submucous plexus to opioid interneurons. The opioid interneurons are in turn linked to excitatory and inhibitory motoneurons. The opioid interneurons are also linked by an intestino-fugal opioid pathway that projects to the prevertebral celiac ganglion, with one or more neural connections therefrom to the central nervous system, including the spinal cord, brain, hypothalamus, and pituitary, and projecting back from the central nervous system to the enteric nervous system.

In particular, the present invention employs a method of manipulating the rate of upper gastrointestinal transit of food or nutrinet substance(s). The method involves administering by an oral or enteral delivery route a pharmaceutically acceptable composition comprising an active agent to the upper gastrointestinal tract. To slow the rate of upper gastrointestinal transit, the active agent is an active lipid; a serotonin, serotonin agonist, or serotonin re-uptake inhibitor; peptide YY or a peptide YY functional analog; calcitonin gene-related peptide (CGRP) or a CGRP functional analog; an adrenergic agonist; an opioid agonist; or a combination of any of any of these, which is delivered in an amount and under conditions such that the cholinergic intestino-fugal pathway, at least one prevertebral ganglionic pathway, the adrenergic efferent neural pathway, the serotonergic interneuron and/or the opioid interneuron are activated thereby. This results in the rate of upper gastrointestinal transit in the subject being slowed, which is the basis for prolonging the residence time of orally or enterally administered food or nutrient substances, thus promoting or enhancing their dissolution and/or absorption in the upper gastrointestinal tract.

The inventive pharmaceutically acceptable compositions limit the presentation of a food or nutrient substance to the proximal region of the small intestine for absorption.

Depending on the desired results, useful active agents include, active lipids; serotonin, serotonin agonists, or serotonin re-uptake inhibitors; peptide YY or peptide YY functional analogs; CGRP or CGRP functional analogs; adrenergic agonists; opioid agonists; or a combination of any of any of these; antagonists of serotonin receptors, peptide YY receptors, adrenoceptors, opioid receptors, CGRP receptors, or a combination of any of these. Also useful are antagonists of serotonin receptors, peptide YY receptors, CGRP receptors; adrenoceptors and/or opioid receptors.

Serotonin, or 5-hydroxytryptamine (5-HT) is preferably used at a dose of about 0.03 to about 0.1 mg/kg of body mass. 5-HT3 and 5-HT4 serotonin receptor agonists are known and include HTF-919 and R-093877 (Foxx-Orenstein, A. E. et al., Am. J. Physiol. 275(5 Pt 1):G979 83 [1998]); prucalopride; 2-[1-(4-Piperonyl)piperazinyl]benzothiazole; 1-(4-Amino-5-chloro-2-methoxyphenyl)-3-[1-butyl-4-piperidinyl]-1-propanon- e; and 1-(4-Amino-5-chloro-2-methoxyphenyl)-3-[1-2-methylsulphonylamino)et- hyl-4-piperidinyl]-1-propanone. Serotonin re-uptake inhibitors include Prozac or Zoloft.

Useful serotonin receptor antagonists include known antagonists of 5-HT3, 5-HT1P, 5-HT1A, 5-HT2, and/or 5-HT4 receptors. Examples include ondansetron or granisetron, 5HT3 receptor antagonists (preferred dose range of about 0.04 to 5 mg/kg), deramciclane (Varga, G. et al,. Effect of deramciclane, a new 5-HT receptor antagonist, on cholecystokinin-induced changes in rat gastrointestinal function, Eur. J. Pharmacol. 367(2 3):315 23 [1999]), or alosetron. 5-HT4 receptor antagonists are preferably used at a dose of about 0.05 to 500 picomoles/kg. 5-HT4 receptor antagonists include 1-Piperidinylethyl1H-indole-3-carboxylate (SB203186); 1-[4-Amino-5-chloro-2-(3,5-dimethoxyphenyl)methyloxy]-3-[1-[2methylsulpho- nylamino]ethyl]piperidin-4-yl]propan-1-one (RS 39604); 3-(Piperidin-1-yl)propyl 4-amino-5-chloro-2-methoxybenzoate.

Peptide YY (PYY) an its functional analogs are preferably delivered at a dose of about 0.5 to about 500 picomoles/kg. PYY functional analogs include PYY (22 36), BIM-43004 (Liu, C D. et al., J. Surg. Res. 59(1):80 84 [1995]), BIM-43073D, BIM-43004C (Litvak, D. A. et al., Dig. Dis. Sci. 44(3):643 48 [1999]). Other examples are also known in the art (e.g., Balasubramaniam, U.S. Pat. No. 5,604,203).

PYY receptor antagonists preferably include antagonists of Y4/PP1, Y5 or Y5/PP2/Y2, and most preferably Y1 or Y2. (E.g., Croom et al., U.S. Pat. No. 5,912,227) Other examples include BIBP3226, CGP71683A (King, P. J. et al., J. Neurochem. 73(2):641 46 [1999]).

CGRP receptor antagonists include human CGRP(8 37) (e.g., Foxx-Orenstein et al., Gastroenterol. 111(5):1281 90 [1996]).

Useful adrenergic agonists include norepinephrine.

Adrenergic or adrenoceptor antagonists include .beta.-adrenoceptor antagonists, including propranolol and atenolol. They are preferably used at a dose of 0.05 2 mg/kg.

Opioid agonists include delta-acting opioid agonists (preferred dose range is 0.05 50 mg/kg, most preferred is 0.05 25 mg/kg); kappa-acting opioid agonists (preferred dose range is 0.005 100 microgram/kg); mu-acting opioid agonists (preferred dose range is 0.05 25 microgram/kg); and episilon-acting agonists. Examples of useful opioid agonists include deltorphins (e.g., deltorphin II and analogues), enkephalins (e.g., [d-Ala(2), Gly-ol(5)]-enkephalin [DAMGO]; [D-Pen(2,5)]-enkephalin [DPDPE]), dinorphins, trans-3,4-dichloro-N-methyl-N-[2-(1-pyrrolidinyl)cyclohexyl-]benzeneaceta- mide methane sulfonate (U-50, 488H), morphine, codeine, endorphin, or .beta.-endorphin.

Opioid receptor antagonists include mu-acting opioid antagonists (preferably used at a dose range of 0.05 5 microgram/kg); kappa opioid receptor antagonists (preferably used at a dose of 0.05 30 mg/kg); delta opioid receptor antagonists (preferably used at a dose of 0.05 200 microgram/kg); and epsilon opioid receptor antagonists. Examples of useful opioid receptor antagonists include naloxone, naltrexone, methylnaltrexone, nalmefene, H2186, H3116, or fedotozine, i.e., (+)-1-1[3,4,5-trimethoxy)benzyloxymethyl]-1-phenyl-N,N-dimethylpropylamin- e. Other useful opioid receptor antagonists are known (e.g., Kreek et al., U.S. Pat. No. 4,987,136).

The active agents listed above are not exhaustive but rather illustrative examples, and one skilled in the art is aware of other useful examples.

As used herein, "active lipid" encompasses a digested or substantially digested molecule having a structure and function substantially similar to a hydrolyzed end-product of fat digestion. Examples of hydrolyzed end products are molecules such as diglyceride, monoglyceride, glycerol, and most preferably free fatty acids or salts thereof In a preferred embodiment, the active agent is an active lipid comprising a saturated or unsaturated fatty acid. Fatty acids contemplated by the invention include fatty acids having between 4 and 24 carbon atoms (C4 C24).

Examples of fatty acids contemplated for use in the practice of the present invention include caprolic acid, caprulic acid, capric acid, lauric acid, myristic acid, oleic acid, palmitic acid, stearic acid, palmitoleic acid, linoleic acid, linolenic acid, trans-hexadecanoic acid, elaidic acid, columbinic acid, arachidic acid, behenic acid eicosenoic acid, erucic acid, bressidic acid, cetoleic acid, nervonic acid, Mead acid, arachidonic acid, timnodonic acid, clupanodonic acid, docosahexaenoic acid, and the like. In a preferred embodiment, the active lipid comprises oleic acid.

Also preferred are active lipids in the form of pharmaceutically acceptable salts of hydrolyzed fats, including salts of fatty acids. Sodium or potassium salts are preferred, but salts formed with other pharmaceutically acceptable cations are also useful. Useful examples include sodium- or potassium salts of caprolate, caprulate, caprate, laurate, myristate, oleate, palmitate, stearate, palmitolate, linolate, linolenate, trans-hexadecanoate, elaidate, columbinate, arachidate, behenate, eicosenoate, erucate, bressidate, cetoleate, nervonate, arachidonate, timnodonate, clupanodonate, docosahexaenoate, and the like. In a preferred embodiment, the active lipid comprises an oleate salt.

The active agents suitable for use with this invention are employed in well dispersed form in a pharmaceutically acceptable carrier. As used herein, "pharmaceutically acceptable carrier" encompasses any of the standard pharmaceutical carriers known to those of skill in the art. For example, one useful carrier is a commercially available emulsion, Ensure.RTM., but active lipids, such as oleate or oleic acid are also dispersible in gravies, dressings, sauces or other comestible carriers. Dispersion can be accomplished in various ways. The first is that of a solution.

Lipids can be held in solution if the solution has the properties of bile (i.e., solution of mixed micelles with bile salt added), or the solution has the properties of a detergent (e.g., pH 9.6 carbonate buffer) or a solvent (e.g., solution of Tween). The second is an emulsion which is a 2-phase system in which one liquid is dispersed in the form of small globules throughout another liquid that is immiscible with the first liquid (Swinyard and Lowenthal, "Pharmaceutical Necessities" REMINGTON'S PHARMACEUTICAL SCIENCES, 17th ed., A R Gennaro (Ed), Philadelphia College of Pharmacy and Science, 1985 p.1296). The third is a suspension with dispersed solids (e.g., microcrystalline suspension). Additionally, any emulsifying and suspending agent that is acceptable for human consumption can be used as a vehicle for dispersion of the composition. For example, gum acacia, agar, sodium alginate, bentonite, carbomer, carboxymethylcellulose, carrageenan, powdered cellulose, cholesterol, gelatin, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methylcellulose, methylcellulose, octoxynol 9, oleyl alcohol, polyvinyl alcohol, povidone, propylene glycol monostearate, sodium lauryl sulfate, sorbitan esters, stearyl alcohol, tragacanth, xantham gum, chondrus, glycerin, trolamine, coconut oil, propylene glycol, thyl alcohol malt, and malt extract.

Any of these formulations, whether it is a solution, emulsion or suspension containing the active agent, can be incorporated into capsules, or a microsphere or particle (coated or not) contained in a capsule.

The pharmaceutically acceptable compositions containing the active agent, in accordance with the invention, is in a form suitable for oral or enteral use, for example, as tablets, troches, lozenges, aqueous or oily suspensions, dispersible powders or granules, emulsions, hard or soft capsules, syrups, elixirs or enteral formulas. Compositions intended for oral use are prepared according to any method known to the art for the manufacture of pharmaceutical compositions. Compositions can also be coated by the techniques described in the U.S. Pat. Nos. 4,256,108; 4,160,452; and 4,265,874, to form osmotic therapeutic tablets for controlled release. Other techniques for controlled release compositions, such as those described in the U.S. Pat. Nos. 4,193,985; and 4,690,822; 4,572,833 can be used in the formulation of the inventive pharmaceutically acceptable compositions.

An effective amount of active lipid is any amount that is effective to slow gastrointestinal transit and control presentation of a food or nutrient substance to a desired region of the small intestine. For example, an effective amount of active lipid, as contemplated by the instant invention, is any amount of active lipid that can trigger any or all of the following reflexes: intestino-lower esophageal sphincter (relaxation of LES); intestino-gastric feedback (inhibition of gastric emptying); intestino-intestinal feedback (ileo-jejunal feedback/ileal brake, jejuno-jejunal feedback/jejunal brake, intestino-CNS feedback (for example, intensifying intestinal signalling of satiety`); intestino-pancreatic feedback (control of exocrine enzyme output); intestino-biliary feedback (control of bile flow); intestino-mesenteric blood flow feedback (for the control of mucosal hyperemia); intestino-colonic feedback (so called gastro-colonic reflex whereby the colon contracts in response to nutrients in the proximal small intestine).

Methods of administering are well known to those of skill in the art and include most preferably oral administration and/or enteral administration. Representative methods of administering include giving, providing, feeding or force-feeding, dispensing, inserting, injecting, infusing, perfusing, prescribing, furnishing, treating with, taking, swallowing, eating or applying. Preferably the pharmaceutically acceptable composition comprising the active agent is administered in the setting of a meal, i.e., along with or substantially simultaneously with the meal, most preferably an hour or less before the meal. It is also useful to administer the active agent in the fasted state, particularly if the pharmaceutical composition containing the active agent is formulated for long acting or extended release. In some embodiments, such as the inventive method for manipulating post-prandial blood flow, the pharmaceutical composition is also usefully administered up to an hour after a meal, and most preferably within one hour before or after the meal.

In order to stretch biologic activity so that one has a convenient, daily dosage regimen, the present invention contemplates that the inventive compositions can be administered prior to ingestion of the food, nutrient and/or drug.

In a preferred embodiment, the inventive compositions (depending on the formulation) are administered up to a period of 24 hours prior to ingestion of the food, nutrient and/or drug, but most preferably between about 60 to 5 minutes before ingestion. The period of time prior to ingestion is determined on the precise formulation of the composition. For example, if the formulation incorporates a controlled release system, the duration of release and activation of the active lipid will determine the time for administration of the composition. Sustained release formulation of the composition is useful to ensure that the feedback effect is sustained.

In a preferred embodiment, the pharmaceutically acceptable composition of the invention contains an active lipid and is administered in a load-dependent manner which ensures that the dispersion of active lipid is presented to the entire length of the small intestine. Administration is in one or more doses such that the desired effect is produced. In some preferred embodiments, the load of active lipid per dose is from about 0.5 grams to about 2.0 grams, but can range up to about 25 grams per dose as needed. Generally, patients respond well to the most preferred amount of active lipid, which is in the range of about 1.6 to 3.2 grams. For patients who fail to respond to this dose range, a dose between 6 and 8 grams is typically effective.

Sequential dosing is especially useful for patients with short bowel syndrome or others with abnormally rapid intestinal transit times. In these patients, the first preprandial administration of the active lipid occurs in a condition of uncontrolled intestinal transit that can fail to permit optimal effectiveness of the active lipid. A second (or more) preprandial administration(s) timed about fifteen minutes after the first or previous administration and about fifteen minutes before the meal enhances the patient's control of intestinal lumenal contents and the effectiveness of the active lipid in accordance with the inventive methods. Normalization of nutrient absorption and bowel control throughout the day, including during the patient's extended sleeping hours, is best achieved by a dietary regimen of three major meals with about five snacks interspersed between them, including importantly, a pre-bedtime snack; administration of a dose of the inventive composition should occur before each meal or snack as described above.

Treatment with the inventive compositions in accordance with the inventive methods can be of singular occurrence or can be continued indefinitely as needed. For example, patients deprived of food for an extended period (e.g., due to a surgical intervention or prolonged starvation), upon the reintroduction of ingestible food, can benefit from administration of the inventive compositions before meals on a temporary basis to facilitate a nutrient adaptive response to normal feeding. On the other hand some patients, for example those with surgically altered intestinal tracts (e.g., ileal resection), can benefit from continued pre-prandial treatment in accordance with the inventive methods for an indefinite period. However, clinical experience with such patients for over six years has demonstrated that after prolonged treatment there is at least a potential for an adaptive sensory feedback response that can allow them to discontinue treatment for a number of days without a recurrence of postprandial diarrhea or intestinal dumping.

The use of pharmaceutiacally acceptable compositions of the present invention in enteral feeding contemplates adding the composition directly to the feeding formula. The composition can either be compounded as needed into the enteral formula when the rate of formula delivery is known (i.e., add just enough composition to deliver the load of active lipids). Alternatively, the composition of the invention can be compounded at the factory so that the enteral formulas are produced having different concentrations of the composition and can be used according to the rate of formula delivery (i.e., higher concentration of composition for lower rate of delivery).

If the inventive composition were to be added to an enteral formula and the formula is continuously delivered into the small intestine, the composition that is initially presented with the nutrient formula allows slowing the transit of nutrients that are delivered later.

Except for the start of feeding when transit can be too rapid because the inhibitory feedback from the composition has yet to be fully activated, once equilibrium is established, it is no longer logistically an issue of delivering the composition as a premeal although the physiologic principle is still the same.

Before dietary fats can be absorbed, the motor activities of the small intestine in the postprandial period must first move the output from the stomach to the appropriate absorptive sites of the small intestine. To achieve the goal of optimizing the movement of a substance through the small intestine, the temporal and spatial patterns of intestinal motility are specifically controlled by the nutrients of the lumenal content.

Without wishing to be bound by any theory, it is presently believed that early in gastric emptying, before inhibitory feedback is activated, the load of fat entering the small intestine can be variable and dependent on the load of fat in the meal. Thus, while exposure to fat can be limited to the proximal small bowel after a small load, a larger load, by overwhelming more proximal absorptive sites, can spill further along the small bowel to expose the distal small bowel to fat. Thus, the response of the duodenum to fat limits the spread of fat so that more absorption can be completed in the proximal small intestine and less in the distal small intestine. Furthermore, since the speed of movement of lumenal fat must decrease when more fat enters the duodenum, in order to avoid steatorrhea, intestinal transit is inhibited in a load-dependent fashion by fat. This precise regulation of intestinal transit occurs whether the region of exposure to fat is confined to the proximal gut or extended to the distal gut.

In accordance with the present invention it has been observed that inhibition of intestinal transit by fat depends on the load of fat entering the small intestine. More specifically, that intestinal transit is inhibited by fat in a load-dependent fashion whether the nutrient is confined to the proximal segment of the small bowel or allowed access to the whole gut.

As described above, the inventive technology can also operate by transmitting to and replicating at a second location in the upper gastrointestinal tract a serotonergic neural signal originating at a first location in the proximal or distal gut of a mammal. For example, the first location can be in the proximal gut and the second location can be elsewhere in the proximal gut or in the distal gut. Or conversely, the first location can be in the distal gut and the second location can be elsewhere in the distal gut or in the proximal gut.

Employing this inventive technology to slow the rate of upper gastrointestinal transit, during and after a meal, nutrient absorption in the upper gastrointestinal tract is enhanced, depriving bacterial populations in the lower small intestine of nutrients. In response to luminal fat in the proximal or distal gut, a serotonin (5-HT)-mediated anti-peristaltic slowing response is normally present. Therefore, some embodiments of the method involve increasing 5-HT in the gut wall by administering to the mammal and delivering to the proximal and/or distal gut, an active lipid, or serotonin, a serotonin agonist, or a serotonin re-uptake inhibitor.

Alternatively, the active agent is PYY, or a PYY functional analog. PYY or the PYY analog activates the PYY-sensitive primary sensory neurons in response to fat or 5-HT. Since the predominant neurotransmitter of the PYY-sensitive primary sensory neurons is calcitonin gene-related peptide (CGRP), in another embodiment, CGRP or a CGRP functional analog is the active agent.

In other embodiments the point of action is an adrenergic efferent neural pathway, which conducts neural signals from one or more of the celiac, superior mesenteric, and inferior mesenteric prevertebral ganglia, back to the enteric nervous system. The active agent is an adrenergic receptor (i.e., adrenoceptor) agonist to activate neural signal transmission to the efferent limb of the anti-peristaltic reflex response to luminal fat.

Since adrenergic efferent neural pathway(s) from the prevertebral ganglia to the enteric nervous system stimulate serotonergic interneurons, which in turn stimulate enteric opioid interneurons, in other embodiments of the method, the active agent is 5-HT, 5-HT receptor agonist, or a 5-HT re-uptake inhibitor to activate or enhance neural signal transmission at the level of the serotoneregic interneurons.

Alternatively, the active agent is an opioid receptor agonist to activate or enhance neural signal transmission via the opioid interneurons.

In accordance with the invention, pharmaceutically acceptable compositions containing the active agent can be in a form suitable for oral use, for example, as tablets, troches, lozenges, aqueous or oily suspensions, dispersible powders or granules, emulsions, hard or soft capsules, syrups, elixirs or enteral formulas. Compositions intended for oral use can be prepared according to any method known to the art for the manufacture of pharmaceutical compositions and such compositions can contain one or more other agents selected from the group consisting of a sweetening agent such as sucrose, lactose, or saccharin, flavoring agents such as peppermint, oil of wintergreen or cherry, coloring agents and preserving agents in order to provide pharmaceutically elegant and palatable preparations. Tablets containing the active ingredient in admixture with non-toxic pharmaceutically acceptable excipients can also be manufactured by known methods. The excipients used can be, for example, (1) inert diluents such as calcium carbonate, lactose, calcium phosphate or sodium phosphate; (2) granulating and disintegrating agents such as corn starch, potato starch or alginic acid; (3) binding agents such as gum tragacanth, corn starch, gelatin or acacia, and (4) lubricating agents such as magnesium stearate, stearic acid or talc. The tablets can be uncoated or they can be coated by known techniques to delay disintegration and absorption in the gastrointestinal tract and thereby provide a sustained action over a longer period. For example, a time delay material such as glyceryl monostearate or glyceryl distearate can be employed. They can also be coated by the techniques described in the U.S. Pat. Nos. 4,256,108; 4,160,452; and 4,265,874, to form osmotic therapeutic tablets for controlled release. Other techniques for controlled release compositions, such as those described in the U.S. Pat. Nos. 4,193,985; and 4,690,822; 4,572,833 can be used in the formulation of the inventive pharmaceutically acceptable compositions.

In some cases, formulations for oral use can be in the form of hard gelatin capsules wherein the active ingredient is mixed with an inert solid diluent, for example, calcium carbonate, calcium phosphate or kaolin. They can also be in the form of soft gelatin capsules wherein the active ingredient is mixed with water or an oil medium, for example, peanut oil, liquid paraffin, or olive oil.

In one embodiment of the present invention, the pharmaceutically acceptable composition is an enterically coated or a sustained release form that permits intestinal transit to be slowed for a prolonged period of time.

In an alternative aspect of the method of treating small intestinal bacterial overgrowth (SIBO) or a SIBO-caused condition in a human subject, after the presence of SIBO is detected in the human subject by suitable detection means, as described above, a pharmaceutically acceptable disinfectant composition is introduced into the lumen of the small intestine so as to contact the bacteria constituting the SIBO condition. The disinfectant composition is introduced in an amount sufficient to inhibit the growth of the bacteria in the small intestine, thereby at least partially eradicating SIBO in the human subject.

Preferably, the pharmaceutically acceptable disinfectant composition consists essentially of hydrogen peroxide; a bismuth-containing compound or salt; or an iodine-containing compound or salt. The pharmaceutically acceptable disinfectant (i.e., bacteriocidal) composition can also contain other non-bacteriocidal ingredients, such as any suitable pharmaceutically acceptable carrier, excipient, emulsant, solvent, colorant, flavorant, and/or buffer, as described hereinabove. Formulations for oral or enteral delivery are useful, as described hereinabove with respect to known delivery modalities for active agents, e.g., tablets, troches, lozenges, aqueous or oily suspensions, dispersible powders or granules, emulsions, hard or soft capsules, syrups, elixirs or enteral formulas.

Embodiments of disinfectant or bacteriocidal compositions containing hydrogen peroxide are known for internal use in vertebrates (e.g., Ultradyne, Ultra Bio-Logics Inc., Montreal, Canada). Preferably, an aquesous solution of about 1% to about 3% (v/v) hydrogen peroxide is introduced orally or otherwise enterally to the lumen, most conveniently by ingestion.

Embodiments of disinfectant or bacteriocidal compositions containing bismuth compounds or salts are also known, for example, bismuth-2-3-dimercaptopropanol (BisBAL), bismuth thiols (e.g., bismuth-ethanedithiol), or bismuth-3,4-dimercaptotoluene (BisTOL), and in over the counter preparations, such as PeptoBizmol. (See, e.g., Domenico, P. et al., Activity of Bismuth Thiols against Staphylococci and Staphylococcal biofilms, Antimicrob. Agents Chemother. 45(5):1417 21 [2001]).

Embodiments of disinfectant or bacteriocidal compositions containing iodine compounds or salts are also known, for example, povidone-iodine solutions.

In still another alternative aspect of the method of treating small intestinal bacterial overgrowth (SIBO) or a SIBO-caused condition in a human subject, after the presence of SIBO is detected in the human subject by suitable detection means, as described above, a pharmaceutically acceptable composition is administered to the subject. The pharmaceutically acceptable composition contains a stabilizer of mast cell membranes in the lumenal wall of the small intestine, in an amount sufficient to inhibit a mast cell-mediated immune response in the human subject. This embodiment is a relatively aggressive treatment and is most useful in more severe or advanced SIBO, for example, as confirmed by high intestinal permeability in the subject (see hereinabove). Suitable mast cell stabilizers include oxatamide or chromoglycate (potassium or sodium salts preferred). (e.g., Pacor, M. L. et al., Controlled study of oxatomide vs disodium chromoglycate for treating adverse reactions to food, Drugs Exp Clin Res 18(3):119 23 [1992]; Stefanini, G. F. et al., Oral cromolyn sodium in comparison with elimination diet in the irritable bowel syndrome, diarrheic type, Multicenter Study of 428 patients, Scand. J. Gastroenterol. 30(6):535 41 [1995]; Andre, F. et al., Digestive permeability to different-sized molecules and to sodium cromoglycate in food allergy, Allergy Proc. 12(5):293 98 [1991]; Lunardi, C. et al., Double-blind cross-over trial of oral sodium cromoglycate in patients with irritable bowel syndrome due to food intolerance, Clin Exp Allergy 21(5):569 72 [1991]; Burks, A. W. et al., Double-blind placebo-controlled trial of oral cromolyn in children with atopic dermatitis and documented food hypersensitivity, J. Allergy Clin. Immunol. 81(2):417 23 [1988]).

After the SIBO condition is at least partially eradicated, typically within a couple of weeks, there is an improvement in the symptom(s) of irritable bowel syndrome, fibromyalgia, chronic fatigue syndrome, chronic pelvic pain syndrome, autism, impaired mentation, impaired memory, depression, ADHD, an autoimmune disease, or Crohn's disease. It is a benefit of the inventive treatment method that after treatment, subjects routinely report feeling better than they have felt in years.

The inventive method of treating small intestinal bacterial overgrowth (SIBO) or a SIBO-caused condition in a human subject, as decribed above, can be optionally combined, simultaneously or in sequence, with other suitable methods of at least partially eradicating small intestinal bacterial overgrowth, such as the following.

For example, at least partially eradicating the bacterial overgrowth is accomplished by administering an antimicrobial agent, including but not limited to a natural, synthetic, or semi-synthetic antibiotic agent. For example, a course of antibiotics such as, but not limited to, neomycin, metronidazole, teicoplanin, doxycycline, tetracycline, ciprofloxacin, augmentin, cephalexin (e.g., Keflex), penicillin, ampicillin, kanamycin, rifamycin, rifaximin, or vancomycin, which may be administered orally, intravenously, or rectally. (R. K. Cleary [1998]; C. P. Kelly and J. T. LaMont, Clostridium difficile infection, Annu. Rev. Med. 49:375 90 [1998]; C. M. Reinke and C. R. Messick, Update on Clostridium difficile-induced colitis, Part 2, Am. J. Hosp. Pharm. 51(15):1892 1901 [1994]).

Alternatively, an antimicrobial chemotherapeutic agent, such as a 4- or 5-aminosalicylate compound is used to at least partially eradicate the SIBO condition. These can be formulated for ingestive, colonic, or topical non-systemic delivery systems or for any systemic delivery systems. Commercially available preparations include 4-(p)-aminosalicylic acid (i.e., 4-ASA or para-aminosalicylic acid) or 4-(p)-aminosalicylate sodium salt (e.g., Nemasol-Sodium.RTM. or Tubasal.RTM.). 5-Aminosalicylates have antimicrobial, as well as anti-inflammatory properties (H. Lin and M. Pimentel, Abstract G3452 at Digestive Disease Week, 100.sup.th Annual Meeting of the AGA, Orlando, Fla. [1999]), in useful preparations including 5-aminosalicylic acid (i.e., 5-ASA, mesalamine, or mesalazine) and conjugated derivatives thereof, available in various pharmaceutical preparations such as Asacol.RTM., Rowasa.RTM., Claversal.RTM., Pentasa.RTM., Salofalk.RTM., Dipentum.RTM. (olsalazine), Azulfidine.RTM. (SAZ; sulphasalazine), ipsalazine, salicylazobenzoic acid, balsalazide, or conjugated bile acids, such as ursodeoxycholic acid-5-aminosalicylic acid, and others.

Another preferred method of at least partially eradicating small intestinal bacterial overgrowth, particularly useful when a subject does not respond well to oral or intravenous antibiotics or other antimicrobial agents alone, is administering an intestinal lavage or enema, for example, small bowel irrigation with a balanced hypertonic electrolyte solution, such as Go-lytely or fleet phosphosoda preparations. The lavage or enema solution is optionally combined with one or more antibiotic(s) or other antimicrobial agent(s). (E g., J. A. Vanderhoof et al., Treatment strategies for small bowel bacterial overgrowth in short bowel syndrome, J. Pediatr. Gastroenterol. Nutr. 27(2):155 60 [1998])

Another preferred method of at least partially eradicating small intestinal bacterial overgrowth employs a probiotic agent, for example, an inoculum of a lactic acid bacterium or bifidobacterium. (A. S. Naidu et al., Probiotic spectra of lactic acid bacteria, Crit. Rev. Food Sci. Nutr. 39(1):13 126 [1999]; J. A. Vanderhoof et al. [1998]; G. W. Tannock, Probiotic propertyies of lactic acid bacteria: plenty of scope for R & D, Trends Biotechnol. 15(7):270 74 [1997]; S. Salminen et al., Clinical uses of probiotics for stabilizing the gut mucosal barrier: successful strains and future challenges, Antonie Van Leeuwenhoek 70(2 4):347 58 [1997]). The inoculum is delivered in a pharmaceutically acceptable ingestible formulation, such as in a capsule, or for some subjects, consuming a food supplemented with the inoculum is effective, for example a milk, yoghurt, cheese, meat or other fermentable food preparation. Useful probiotic agents include Bifidobacterium sp. or Lactobacillus species or strains, e.g., L. acidophilus, L. rhamnosus, L. plantarum, L. reuteri, L. paracasei subsp. paracasei, or L. casei Shirota, (P. Kontula et al., The effect of lactose derivatives on intestinal lactic acid bacteria, J. Dairy Sci. 82(2):249 56 [1999]; M. Alander et al., The effect of probiotic strains on the microbiota of the Simulator of the Human Intestinal Microbial Ecosystem (SHIME), Int. J. Food Microbiol. 46(1):71 79 [1999]; S. Spanhaak et al., The effect of consumption of milk fermented by Lactobacillus casei strain Shirota on the intestinal microflora and immune parameters in humans, Eur. J. Clin. Nutr. 52(12):899 907 [1998]; W. P. Charteris et al., Antibiotic susceptibility of potentially probiotic Lactobacillus species, J. Food Prot. 61(12):1636 43 [1998]; B. W. Wolf et al., Safety and tolerance of Lactobacillus reuteri supplementation to a population infected with the human immunodeficiency virus, Food Chem. Toxicol. 36(12):1085 94 [1998]; G. Gardiner et al., Development of a probiotic cheddar cheese containing human-derived Lactobacillus paracasei strains, Appl. Environ. Microbiol. 64(6):2192 99 [1998]; T. Sameshima et al., Effect of intestinal Lactobacillus starter cultures on the behaviour of Staphylococcus aureus in fermented sausage, Int. J. Food Microbiol. 41(1):1 7 [1998]).

Optionally, after at least partial eradication of small intestinal bacterial overgrowth, use of antimicrobial agents or probiotic agents can be continued to prevent further development or relapse of SIBO.

Another preferred method of at least partially eradicating small intestinal bacterial overgrowth is by normalizing or increasing phase III interdigestive intestinal motility between meals with any of several modalities to at least partially eradicate the bacterial overgrowth, for example, by suitably modifying the subject's diet to increase small intestinal motility to a normal level (e.g., by increasing dietary fiber), or by administration of a chemical prokinetic agent to the subject, including bile acid replacement therapy when this is indicated by low or otherwise deficient bile acid production in the subject.

For purposes of the present invention, a prokinetic agent is any chemical that causes an increase in phase III interdigestive motility of a human subject's intestinal tract. Increasing intestinal motility, for example, by administration of a chemical prokinetic agent, prevents relapse of the SIBO condition, which otherwise typically recurs within about two months, due to continuing intestinal dysmotility. The prokinetic agent causes an in increase in phase III interdigestive motility of the human subject's intestinal tract, thus preventing a recurrence of the bacterial overgrowth. Continued administration of a prokinetic agent to enhance a subject's phase III interdigestive motility can extend for an indefinite period as needed to prevent relapse of the SIBO condition.

Preferably, the prokinetic agent is a known prokinetic peptide, such as motilin, or functional analog thereof, such as a macrolide compound, for example, erythromycin (50 mg/day to 2000 mg/day in divided doses orally or I.V. in divided doses), or azithromycin (250 1000 mg/day orally).

However, a bile acid, or a bile salt derived therefrom, is another preferred prokinetic agent for inducing or increasing phase III interdigestive motility. (E. P. DiMagno, Regulation of interdigestive gastrointestinal motility and secretion, Digestion 58 Suppl. 1:53 55 [1997]; V. B. Nieuwenhuijs et al., Disrupted bile flow affects interdigestive small bowel motility in rats, Surgery 122(3):600 08 [1997]; P. M. Hellstrom et al., Role of bile in regulation of gut motility, J. Intern. Med. 237(4):395 402 [1995]; V. Plourde et al., Interdigestive intestinal motility in dogs with chronic exclusion of bile from the digestive tract, Can. J. Physiol. Pharmacol. 65(12):2493 96 [1987]). Useful bile acids include ursodeoxycholic acid and chenodeoxycholic acid; useful bile salts include sodium or potassium salts of ursodeoxycholate or chenodeoxycholate, or derivatives thereof.

A compound with cholinergic activity, such as cisapride (i.e., Propulsid.RTM.; 1 to 20 mg, one to four times per day orally or I.V.), is also preferred as a prokinetic agent for inducing or increasing phase III interdigestive motility. Cisapride is particularly effective in alleviating or improving hyperalgesia related to SIBO or associated with disorders caused by SIBO, such as IBS fibromyalgia, or Crohn's disease.

A dopamine antagonist, such as metoclopramide (1 10 mg four to six times per day orally or I.V.), domperidone (10 mg, one to four times per day orally), or bethanechol (5 mg/day to 50 mg every 3 4 hours orally; 5 10 mg four times daily subcutaneously), is another preferred prokinetic agent for inducing or increasing phase III interdigestive motility. Dopamine antagonists, such as domperidone, are particularly effective in alleviating or improving hyperalgesia related to SIBO or associated with disorders caused by SIBO, such as IBS, fibromyalgia, or Crohn's disease.

Also preferred is a nitric oxide altering agent, such as nitroglycerin, nomega-nitro-L-arginine methylester (L-NAME), N-monomethyl-L-arginine (L-NMMA), or a 5-hydroxytryptamine (HT or serotonin) receptor antagonist, such as ondansetron (2 4 mg up to every 4 8 hours I.V.; pediatric 0.1 mg/kg/day) or alosetron. The 5-HT receptor antagonists, such as ondansetron and alosetron, are particularly effective in improving hyperalgesia related to SIBO, or associated with disorders caused by SIBO, such as IBS, fibromyalgia, or Crohn's disease.

An antihistamine, such as promethazine (oral or I.V. 12.5 mg/day to 25 mg every four hours orally or I.V.), meclizine (oral 50 mg/day to 100 mg four times per day), or other antihistamines, except ranitidine (Zantac), famotidine, and nizatidine, are also preferred as prokinetic agents for inducing or increasing phase III interdigestive motility.

Also preferred are neuroleptic agents, including prochlorperazine (2.5 mg/day to 10 mg every three hours orally; 25 mg twice daily rectally; 5 mg/day to 10 mg every three hours, not to exceed 240 mg/day intramuscularly; 2.5 mg/day to 10 mg every four hours I.V.), chlorpromazine (0.25 mg/lb. up to every four hours [5 400 mg/day] orally; 0.5 mg/lb. up to every 6 hours rectally; intramuscular 0.25/lb. every six hours, not to exceed 75/mg/day), or haloperidol (oral 5 10 mg/day orally; 0.5 10 mg/day I.V.). Also useful as a prokinetic agent, for purposes of the present invention, is a kappa agonist, such as fedotozine (1 30 mg/day), but not excluding other opiate agonists. The opiate (opioid) agonists, such as fedotozine, are particularly effective in alleviating or improving hyperalgesia related to SIBO or associated with disorders caused by SIBO, such as IBS, fibromyalgia, or Crohn's disease.

The preceding are merely illustrative of the suitable means by which small intestinal bacterial overgrowth is at least partially eradicated by treatment in accordance or in combination with the inventive methods. These means can be used separately, or in combination, by the practitioner as suits the needs of an individual human subject.

Optionally, treating further includes administering to the human subject an anti-inflammatory cytokine or an agonist thereof, substantially simultaneously with or after at least partially eradicating the bacterial overgrowth of the small intestine, to accelerate or further improve the symptom(s) of irritable bowel syndrome, fibromyalgia, chronic fatigue syndrome, depression, ADHD, or an autoimmune disease, or Crohn's disease. Useful anti-inflammatory cytokines include human IL-4, IL-10, IL-11, or TGF-.beta., derived from a human source or a transgenic non-human source expressing a human gene. The anti-inflammatory cytokine is preferably injected or infused intravenously or subcutaneously.

Optionally, when the suspected diagnosis is irritable bowel syndrome, fibromyalgia, chronic fatigue syndrome, depression, ADHD, or an autoimmune disease, such as multiple sclerosis or systemic lupus erythematosus, symptoms are improved by administering an antagonist of a pro-inflammatory cytokine or an antibody that specifically binds a pro-inflammatory cytokine. The antagonist or antibody is administered to the human subject substantially simultaneously with or after treatment to at least partially eradicate the bacterial overgrowth. The antagonist or antibody is one that binds to a pro-inflammatory cytokine or antogonizes the activity or receptor binding of a pro-inflammatory cytokine. Pro-inflammatory cytokines include TNF-.alpha., IL-1.alpha., IL-1.beta., IL-6, L-8, IL-12, or LIF. The cytokine antagonist or antibody is preferably derived from a human source or is a chimeric protein having a human protein constituent. The cytokine antagonist or antibody is preferably delivered to the human subject by intravenous infusion.

Optionally, the method of treating irritable bowel syndrome, fibromyalgia, chronic fatigue syndrome, depression, attention deficit/hyperactivity disorder, an autoimmune disease, or Crohn's disease, further comprises administering an agent that modifies afferent neural feedback or sensory perception. This is particularly useful when, after at least partial eradication of SIBO, the subject experiences residual symptoms of hyperalgesia related to SIBO or associated with a disorder caused by SIBO, such as IBS fibromyalgia, or Crohn's disease. Agents that modify afferent neural feedback or sensory perception include 5-HT receptor antagonists, such as ondansetron and alosetron; opiate agonists, such as fedotozine; peppermint oil; cisapride; a dopamine antagonist, such as domperidone; an antidepressant agent; an anxiolytic agent; or a combination of any of these. Useful antidepressant agents include tricyclic antidepressants, such as amitriptyline (Elavil); tetracyclic antidepressants, such as maprotiline; serotonin re-uptake inhibitors, such as fluoxetine (Prozac) or sertraline (Zoloft); monoamine oxidase inhibitors, such as phenelzine; and miscellaneous antidepressants, such as trazodone, venlafaxine, mirtazapine, nefazodone, or bupropion (Wellbutrin). Typically, useful antidepressant agents are available in hydrochloride, sulfated, or other conjugated forms, and all of these conjugated forms are included among the useful antidepressant agents. Useful anxiolytic (anti-anxiety) agents include benzodiazepine compounds, such as Librium, Atavin, Xanax, Valium, Tranxene, and Serax, or other anxiolytic agents such as Paxil.

Eradication of the bacterial overgrowth is determined by detection methods described above, particularly in comparison with recorded results from pre-treatment detection. After at least partially eradicating the bacterial overgrowth, in accordance with the present method, the symptom(s) of irritable bowel syndrome, fibromyalgia, chronic fatigue syndrome, depression, ADHD, an autoimmune disease, or Crohn's disease are improved. Improvement in a symptom(s) is typically determined by self-reporting by the human subject, for example by VAS scoring or other questionnaire. Improvement in academic, professional, or social functioning, e.g., in cases of ADHD or depression can also be reported by others or can be observed by the clinician. Improvement (increase) in pain threshold, e.g., in subjects diagnosed with fibromyalgia, can be measured digitally, for example, by tender point count, or mechanically, for example, by dolorimetry. (F. Wolfe et al., Aspects of Fibromyalgia in the General Population: Sex, Pain Threshold, and Fibromyalgia Symptoms, J. Rheumatol. 22:151 56 [1995]). Improvement in visceral hypersensitivity or hyperalgesia can be measured by balloon distension of the gut, for example, by using an electronic barostat. (B. D. Nabiloff et al., Evidence for two distinct perceptual alterations in irritable bowel syndrome, Gut 41:505 12{1997]). Some improvement(s) in symptoms, for example systemic lupus erythematosus symptoms, such as rashes, photosensitivity, oral ulcers, arthritis, serositis, or improvements in the condition of blood, kidney or nervous system, can be determined by clinical observation and measurement.

The present invention also relates to a kit for the diagnosis of SIBO or a SIBO-caused condition. The kit comprises at least one breath sampling container, a pre-measured amount of a substrate, and instructions for a user in detecting the presence or absence of SIBO by determining the relative amounts of methane, hydrogen, and at least one sulfur-containing gas in a gas mixture exhaled by the human subject, after the human subject has ingested a controlled quantity of the substrate. The present kit is useful for practicing the inventive method of detecting SIBO in a human subject, as described hereinabove.

The kit is a ready assemblage of materials or components for facilitating the detection of small intestinal bacterial overgrowth, in accordance with the present invention. The kit includes suitable storage means for containing the other components of the kit. The kit includes at least one, and most preferably multiple, air-tight breath sampling container(s), such as a bag, cylinder, or bottle, and at least one pre-measured amount of a substrate,which is preferably an isotope-labeled substrate or substrate that is poorly digestible by a human. Preferably the substrate is a sugar, such as lactulose (e.g., 10 20 g units) or xylose, or a sugar, such as glucose (e.g., 75 80 g units), lactose, or sucrose, for measuring breath hydrogen, methane, and at least one sulfur-containing gas, such as hydrogen sulfide, a sulfhydryl compound, methanethiol, dimethylsulfide, dimethyl disulfide, an allyl methyl sulfide, an allyl methyl sulfide, an allyl methyl disulfide, an allyl disulfide, an allyl mercaptan, or a methylmercaptan.

The present kit also contains instructions for a user in how to use the kit to detect small intestinal bacterial overgrowth (SIBO) or to corroborate a suspected diagnosis of irritable bowel syndrome, fibromyalgia, chronic fatigue syndrome, chronic pelvic pain syndrome, autism, impaired mentation, impaired memory, depression, ADHD, an autoimmune disease, or Crohn's disease, in accordance with the present methods.

Optionally, the kit also contains compositions useful for at least partially eradicating SIBO, as described above.

The components assembled in the kits of the present invention are provided to the practitioner stored in any convenient and suitable way that preserves their operability and utility. For example the components can be in dissolved, dehydrated, or lyophilized form; they can be provided at room, refrigerated or frozen temperatures.
 


Claim 1 of 3 Claims

1. A method of treating irritable bowel syndrome in a human subject comprising: detecting the presence of small intestinal bacterial overgrowth in the subject; and at least partially eradicating the small intestinal bacterial overgrowth by depriving the bacterial overgrowth of nutrients by causing the subject to consume a diet comprising VIVONEX.RTM.

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