Link:  Pharm/Biotech Resources

Title:  Treatment of shock using adrenomedullin binding protein-1

United States Patent:  6,884,781

Issued:  April 26, 2005

Inventors:  Wang; Ping (59 Highland Ave., Roslyn, NY 11576)

Appl. No.:  729193

Filed:  December 5, 2003

Abstract

Methods of treating a mammal in shock or at risk for shock are provided. The methods involve administration of an adrenomedullin binding protein-1 to the mammal. Also provided are methods of preventing or treating a physiologic effect of shock in a mammal. These methods also involve administration of an adrenomedullin binding protein-1 to the mammal.

Description of the Invention

BACKGROUND OF THE INVENTION

(1) Field of the Invention

This invention generally relates to treatment of shock. More specifically, the invention is directed to the administration of adrenomedullin binding protein-1 to mammals in shock or at risk for shock.

(2) Description of the Related Art

References Cited

Elsasser T H, Kahl S, Martinez A, Montuenga L M, Pio R, Cuttitta F: Adrenomedullin binding protein in the plasma of multiple species: characterization by radioligand blotting. Endocrinol 140:4908-4911, 1999.

Shindo T, Kurihara H, Maemura K, Kurihara Y, Kuwaki T, Izumida T, Minamino N, Ju K H, Morita H, Oh-hashi Y, Kumada M, Kangawa K, Nagai R, Yazaki Y: Hypotension and resistance to lipopolysaccharide-induced shock in transgenic mice overexpressing adrenomedullin in their vasculature. Circulation 101:2309-2316, 2000.

Wichterman K A, Baue A E, Chaudry I H: Sepsis and septic shock: a review of laboratory models and a proposal. J Surg Res 29:189-201, 1980.

Wu R, Zhou M, Wand P: Adrenomedullin and adrenomedullin binding protein-1 downregulate TNF-α in macrophage cell line and rat Kupffer cells. Regul Pept 112:19-26, 2003.

Yang S, Zhou M., Chaudry I H: Novel approach to prevent the transition from the hyperdynamic phase to the hypodynamic phase of sepsis: Role of adrenomedullin and adrendomedullin binding protein-1. Ann Surg 236:625-633, 2002a.

Yang S, Zhou M, Gowler D E, Wang P: Mechanisms of the beneficial effect of adrenomedullin and adrenomedullin-binding protein-1 in sepsis: down-regulation of proinflammatory cytokines. Crit Care Med 30:2729-2735, 2002b.

Shock, or circulatory insufficiency leading to inadequate blood flow to vital organs, is a potentially life-threatening medical emergency that often leads to organ damage, cardiac arrest, respiratory failure and death.

Shock can be caused by heart problems (cardiogenic shock), conditions blocking blood flow to or from the heart (extracardiac obstructive shock), loss of fluids (hypovolemic shock), or abnormal flow of fluids into the tissues (distributive shock). These dysfunctions in circulation can in turn be caused by bacterial blood infection (septic shock), severe allergic reaction (anaphylaxis), trauma (traumatic shock), severe bleeding (hemorrhagic shock), or neurologic dysfunction causing abnormal opening of blood vessels (neurogenic shock). While any shock is serious, septic shock and hypovolemic shock are particularly important due to their frequency of occurrence and frequently inadequate treatment regimens.

Despite attempts to improve survival of septic patients with intensive medical care, including antibiotics, aggressive intravenous fluids, nutrition, mechanical ventilation, and surgical interventions, the mortality rate still ranges from 30% to 50%. Of clinical trials testing novel agents for the treatment of sepsis, only activated protein C has previously been demonstrated to significantly reduce mortality in patients with severe sepsis. The high morbidity and mortality attributed to sepsis could be due to the fact that mediators or factors responsible for the transition from the hyperdynamic phase to the hypodynamic phase of sepsis are not fully understood. Consequently, there is a progressive deterioration of cell and organ functions and even death of the host, which might be prevented by interventions directed against and/or modulating these mediators/factors. It is therefore important to investigate the subtle alterations in cellular function and mechanisms of pathophysiological changes during sepsis and develop novel therapeutic strategies. In this regard, experimental polymicrobial sepsis induced by cecal ligation and puncture (CLP) mimics many features of clinical sepsis-peritonitis and is associated with an early, hyperdynamic phase (characterized by increased cardiac output and tissue perfusion, decreased vascular resistance, hyperglycemia and hyperinsulinemia) followed by a late, hypodynamic phase (characterized by reduced cardiac output and tissue perfusion, increased vascular resistance, hypoglycemia and hypoinsulinemia). The CLP model of sepsis has been used extensively to study the pathophysiologic and immunologic alterations in sepsis.

Despite advances in the trauma management, a large number of patients with traumatic injury die of hypovolemic circulatory collapse due to severe hemorrhage. Irreversible circulatory shock induced by traumatic injury and blood loss represent a major clinical problem, particularly in combat casualties. Traumatic injury (often accompanied by severe blood loss) is the principal cause of death in patients aged 1-44 years and the overall leading cause of life-years lost in the United States. Traumatic injury accounts for 37 million emergency department visits, 2.6 million hospital admissions, and 150,000 deaths each year. The resulting loss of productive life years exceeds that of any other disease, with societal costs of $260 billion annually. In less than two decades, trauma will equal to or surpass communicable diseases as the leading worldwide cause of disability-adjusted life-years lost. Although more effective prevention measures will reduce the early deaths resulting from massive hemorrhage and central nervous system injury, the transition from the reversible to the irreversible hypovolemia, or circulatory collapse, appears to be responsible for the majority of late deaths after trauma and blood loss.

Shock generally progresses in four stages. The initial stage is characterized by cardiac output insufficient to meet the body's metabolic needs, but not otherwise low enough to produce significant symptoms. The patient is anxious and alert, with altered mental status, and increased respirations. In the second, or compensatory, stage the patient exhibits an increase in heart rate, an increase in cardiac output, and vasoconstriction. The third, or progressive, stage of shock is characterized by falling blood pressure, increased heart rate, oligoria, and increasing system dysfunction. In the fourth, or irreversible stage, death is inevitable. The patient in the irreversible stage exhibits myocardial depression and massive capillary dilation, with blood pooling in the extremities.

Adrenomedullin, a newly reported and potent vasodilatory peptide, is an important mediator involved in both physiological and pathological states. Human AM, a 52-amino acid peptide, was first isolated and reported in 1993. AM has a carboxy terminal amidated residue and a 6-member ring structure formed by an intramolecular disulfide bond near the amino terminus, and is available commercially. Rat adrenomedullin has 50 amino acids with 2 amino acid deletions and 6 substitutions as compared to human adrenomedullin. Adrenomedullin transcripts and protein are expressed in a large number of tissues, and circulating levels of adrenomedullin were observed under normal as well as pathophysiological conditions. Previous studies using the CLP model of sepsis have shown that up-regulation of adrenomedullin plays a major role in initiating the hyperdynamic response during the early stage of sepsis, and reduced vascular responsiveness to adrenomedullin appears to be responsible for the transition from the hyperdynamic phase to the hypodynamic phase during the progression of polymicrobial sepsis.

In 1999, Elsasser et al. reported that specific adrenomedullin binding proteins (AMBP) exist in the plasma of several species including humans. More recently, the binding protein AMBP-1 has been identified in human plasma and has been shown to be identical to human complement factor H. AMBP-1 enhances adrenomedullin-mediated induction of cAMP in fibroblasts, augments the adrenomedullin-mediated growth of a cancer cell line, and suppresses the bactericidal capability of adrenomedullin on E. coli.

Studies by Shindo et al. (2000) have shown that a chronic increase in vascular adrenomedullin production in transgenic mice is protective against circulatory collapse, organ damage, and mortality of endotoxic shock. It was previously unknown whether adrenomedullin+AMBP-1 down-regulates proinflammatory cytokines and, if so, whether the beneficial effects of adrenomedullin+AMBP-1 are due to this down-regulation.

It has been previously demonstrated that proinflammatory cytokines play a critical role in the initiation and progression of sepsis syndrome and that TNF-α, IL-1β and IL-6 are important mediators of hemodynamic, metabolic and immunologic alterations in the host during sepsis. Studies have also shown that circulating levels of TNF-α, IL-1β and IL-6 increase significantly in the early, hyperdynamic phase of sepsis and remain elevated in the late, hypodynamic phase of sepsis. Although adrenomedullin is up-regulated following stimulation with TNF-α and IL-1β, some studies have shown that adrenomedullin suppresses IL-1β-induced TNF-α production in vivo and suppresses the secretion of TNF-α and IL-6 from RAW 264.7 cells stimulated with endotoxin in vitro.

BRIEF SUMMARY OF THE INVENTION

The instant invention is based on the discovery that adrenomedullin binding protein-1 (AMBP-1) is limiting relative to adrenomedullin in shock, and addition of AMBP-1 beneficially reduces physiologic effects of shock.

Thus, in some embodiments, the invention is directed to methods of treating a mammal in shock or at risk for shock. The methods comprise administering an adrenomedullin binding protein-1 (AMBP-1) to the mammal in sufficient amount to reduce a physiologic effect of the shock.

In other embodiments, the invention is directed to methods of preventing or treating a physiologic effect of shock in a mammal. The methods comprise administering to the mammal an adrenomedullin binding protein-1 (AMBP-1) in sufficient amount to reduce the physiologic effect of the shock.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is based on the discovery that adrenomedullin binding protein-1 (AMBP-1) is limiting relative to adrenomedullin during shock, which limits the effectiveness of adrenomedullin therapy for reducing deleterious effects of shock. Administration of AMBP-1 alleviates this adrenomedullin hyporesponsiveness and is thus a useful therapy for shock.

Thus, in some embodiments, the invention is directed to methods of treating a mammal in shock or at risk for shock. The methods comprise administering an adrenomedullin binding protein-1 (AMBP-1) to the mammal in sufficient amount to reduce a physiologic effect of the shock.

In these methods, the shock has an initial stage, a compensatory stage, and a progressive stage, which are physiologically distinguishable, as discussed above, under Background of the Invention. Although these three stages are believed to be present in all cases of shock, the duration of each stage can vary widely, depending on the severity and type of shock, such that it may be difficult to identify one or two of the stages.

AMBP-1 is preferably administered along with adrenomedullin, in order to maximize the therapeutic effect of the AMBP-1 administration.

These methods can be effectively used in any mammalian species, including experimental animals such as rat, mouse and guinea pig; domesticated animals such as horse, dog, pig, rabbit, cat and ferret; as well as humans.

The AMBP-1 and adrenomedullin administered in these methods can be from any mammalian species, but is preferably from the same mammalian species being treated, to minimize the possibility of allergic reactions to the treatment. Thus, a human can be treated with an AMBP-1 (and adrenomedullin, when desired) from any mammalian species, but treatment with the human forms of these proteins is preferred. The AMBP-1 and adrenomedullin can also be from the same or different species. AMBP-1 and adrenomedullin from numerous species have been cloned and sequenced. Examples include the following GenBank accessions: Y00716 (human AMBP-1), NM 130409 (rat AMBP-1), NM 009888 (mouse AMBP-1), AAH15961 (human adrenomedullin), AAH61775 (rat adrenomedullin), AAH52665 (mouse adrenomedullin), NP 776313 (cow adrenomedullin), S41600 (pig adrenomedullin), and BAA96494 (horse adrenomedullin). Using this information, the skilled artisan could identify AMBP-1 and adrenomedullin from any other mammalian species without undue experimentation.

The AMBP-1 or adrenomedullin for these methods could also be a synthetic protein, not identical to that from any species. The skilled artisan could identify numerous such proteins, using the sequence information provided in the above-identified GenBank accessions, by simply altering one of the above sequences by, e.g., substituting amino acid residues (or nucleotides encoding the amino acids) from one species into the sequence of another species. Additionally, the AMBP-1 or adrenomedullin can be a peptidomimetic or other known forms that are more resistant to degradation than the natural polypeptides. Examples include groups such as amides or ester groups attached to the peptides, since such protected peptides would be deprotected in vivo to deliver the active adrenomedullin and AMBP-1.

Synthesis of the AMBP-1 or adrenomedullin for these methods can be by any known method, e.g., synthesis by peptide synthetic methods or, preferably, expression from an expression vector in bacterial, yeast or mammalian cells.

These methods are useful for treatment of mammals undergoing, or at risk for, any type of shock, including cardiogenic shock, extracardiac obstructive shock, hypovolemic shock, distributive shock, septic shock, anaphylaxis, traumatic shock, hemorrhagic shock, and neurogenic shock. In preferred embodiments, the shock is hypovolemic shock (including hemorrhagic shock), traumatic shock, and septic shock.

Depending on the type and severity of shock, these treatments would be expected to beneficially reduce at least one physiologic effect of shock, including endothelial cell function, smooth muscle contractility, cardiac output, stroke volume, systemic oxygen delivery, regional blood perfusion, renal function, hepatic function, gut absorptive function, adrenal function, insulin responsiveness, lactic acidosis, hemoconcentration, total peripheral vascular resistance, or IL-10, TNF-α, IL-1β or IL-6 release.

The amount of AMBP-1 administered will depend on the size and condition of the patient. Generally, the dosage of AMBP-1 of 0.2 to 100 μg/kg body weight, including, for example, 0.5, 1, 2, 5, 10, 25, and 50 μg/kg, would be deemed appropriate, with the dosage on the low end of the dosage range being appropriate for the adult human. Where utilized, adrenomedullin of 0.1 to 50 μg/kg body weight, including, for example, 0.2, 0.5, 1, 2, 5, 10, and 25 μg/kg is appropriate. The compositions containing the active agents may be administered intravenously as a continuous drip. This is the most likely mode of administration, since these patients are generally hospitalized because of the gravity of their condition. The active agents are soluble, and would usually be administered in isotonic solutions such as Ringer's solution, buffered saline, etc. While liposomes may be prepared, such are usually not needed for protection when the agents are given by intravenous drip. However, the invention is not narrowly limited to any particular form of administration, and modes of administration other than continuous drip intravenous administration are within the scope of the invention. Because the peptides are water-soluble, it is possible to give them in aqueous solutions without addition of solubilizing agents.

The AMBP-1 can be administered prophylactically at any time before initiation of shock, for example, during or after a septic pregnancy or delivery, a trauma, a heart attack, or when anaphylaxis is feared. Alternatively, the AMBP-1 can be administered during the initial, compensatory, or progressive stage of shock. Preferably, the AMBP-1 is administered within 90 minutes of the initiation of the shock, to reduce or prevent organ damage caused by the shock. When adrenomedullin is also administered, it can be administered before, during, or after administration of the AMBP-1.

The AMBP-1 (and adrenomedullin) can also be administered in conjunction with another agent that reduces a physiological effect of the shock. Nonlimiting examples of such agents include vasodilators, vasopressors, corticosteroids, antibiotics, and opiates.

In other embodiments, the invention is directed to methods of preventing or treating a physiologic effect of shock in a mammal. The methods comprise administering to the mammal an adrenomedullin binding protein-1 (AMBP-1) in sufficient amount to reduce the physiologic effect of the shock. As with the previously described embodiments, the AMBP-1 is preferably administered with adrenomedullin. Also as previously described, the physiologic effect can be one or more of endothelial cell function, smooth muscle contractility, cardiac output, stroke volume, systemic oxygen delivery, regional blood perfusion, renal function, hepatic function, gut absorptive function, adrenal function, insulin responsiveness, lactic acidosis, hemoconcentration, total peripheral vascular resistance, or IL-10, TNF-α, IL-1β or IL-6 release.

As with the previously described embodiments, these methods can be used on any mammal including humans, and the AMBP-1 or adrenomedullin can be from any mammalian species. It can also be altered to resist rapid degradation in the mammal, as described above. These methods can also be used with any type of shock, and the AMBP-1 can be administered at any time before initiation of shock, and/or during the initial, compensatory, or progressive stage of the shock.

Claim 1 of 20 Claims

1. A method of treating a mammal in shock or at risk for shock, the shock having an initial stage, a compensatory stage, and a progressive stage, the method comprising administering an adrenomedullin binding protein-1 (AMBP-1) to the mammal in sufficient amount to reduce a physiologic effect of the shock.

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