Internet for Pharmaceutical and Biotech Communities
| Newsletter | Advertising |
 
 
 

  

Pharm/Biotech
Resources

Outsourcing Guide

Cont. Education

Software/Reports

Training Courses

Web Seminars

Jobs

Buyer's Guide

Home Page

Pharm Patents /
Licensing

Pharm News

Federal Register

Pharm Stocks

FDA Links

FDA Warning Letters

FDA Doc/cGMP

Pharm/Biotech Events

Consultants

Advertiser Info

Newsletter Subscription

Web Links

Suggestions

Site Map
 

 
   



 

Title:  PRP composition and minimally invasive method for treating myocardial infarction
United States Patent: 
7,314,617
Issued: 
January 1, 2008

Inventors: 
Mishra; Allan (Menlo Park, CA)
Appl. No.: 
10/941,124
Filed: 
September 15, 2004


 

Web Seminars -- Pharm/Biotech/etc.


Abstract

Methods are described for using compositions containing platelet-rich plasma for the treatment of a variety of tissue lesions. Particularly, delivery of platelet-rich plasma to connective tissue is described. The described method and compositions have been shown to provide both pain relief and improved mobility in treatment of lateral epicondylitis.

Description of the Invention

SUMMARY OF THE INVENTION

In one embodiment, the present invention is drawn to a method of treating an injured tissue in an individual including the steps of determining a site of tissue injury in the individual; and introducing a platelet-rich plasma composition into and around the site of tissue injury. In preferred embodiments, the tissue is selected from the group consisting of connective tissue, cardiac muscle, skeletal muscle, disc material, a vertebral body, brain, spinal cord, and vascular tissue. In a preferred embodiment, the tissue is a part of an internal organ. In a more preferred embodiment, the internal organ is the pancreas. In a particularly preferred embodiment, the tissue is a connective tissue.

In preferred embodiments the platelet-rich plasma is titrated to obtain a pH of about 7.3 to 7.5. In a more preferred embodiment, the titration is performed using a bicarbonate buffer.

In preferred embodiments, the platelet-rich plasma composition includes platelets obtained from the individual who is to be treated with the platelet-rich plasma composition. In a preferred embodiment, no exogenous activator is added to the composition prior to its introduction into and around the site of injury.

In some embodiments, the method includes the step of mixing into the platelet composition substantially simultaneously with the introduction into and around the site of tissue injury, one or more ingredients including but not limited to thrombin, epinephrine, collagen, calcium salts, and pH adjusting agents.

In one embodiment the present invention is drawn to a platelet-rich plasma composition for the treatment of an injured tissue which includes platelet-rich plasma; and a pH adjusting agent, wherein the composition does not contain an activator of the platelet-rich plasma. In a preferred embodiment, the pH of the platelet-rich plasma composition is adjusted to a pH of about 7.3 to 7.5 with a pH adjusting agent. In a more preferred embodiment, the pH adjusting agent is a bicarbonate buffer. Preferably, the plasma used for the platelet-rich plasma is from an autologous source.

In one embodiment, the present invention is drawn to a method of making a platelet-rich plasma composition including the steps of drawing blood from an individual; obtaining a plasma fraction from the blood; isolating platelets from the plasma fraction; resuspending the platelets in a reduced amount of plasma; and adjusting the pH to provide a pH of 7.3 to 7.5 for the resuspended platelets to provide a platelet-rich plasma composition, wherein an activator of the platelet-rich plasma is not added to the platelet-rich plasma composition.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The inventor has surprisingly discovered that certain inventive platelet compositions are useful for the treatment of several types of tissue damage or injury. As used herein, the term "injury" is a broad term and is used in the ordinary sense to refer, without limitation, to any tissue damage including a wound, trauma or lesion or any tissue degeneration. In particular, the inventive platelet compositions may be used to treat incomplete repair of various connective tissues.

In one aspect, the invention relates to a method of treating incomplete repair in a patient's connective tissue comprising: obtaining a platelet composition; determining a lesion that comprises the incomplete repair in the patient's connective tissue; and minimally invasively introducing the platelet composition into and around the lesion. In an aspect, the invention relates to the method wherein the platelet composition is at or above physiological pH. In an aspect, the invention relates to the method wherein the platelet composition optionally includes platelet releasate. In an aspect, the invention relates to the method further comprising: mixing into the platelet composition one or more of the ingredients selected from thrombin, epinephrine, collagen, calcium salts, and pH adjusting agents. Also useful are materials to promote degranulation or preserve platelets, additional growth factors or growth factor inhibitors, small molecule pharmaceuticals such as NSAIDS, steroids, and anti-infective agents. In an aspect, the invention relates to the method wherein the patient's connective tissue is selected from: tendons, ligaments, joint capsules, and fascial tissues. In an aspect, the invention relates to the method wherein obtaining the platelet composition comprises: drawing blood from a human; and centrifuging the blood to obtain a plasma-rich fraction. In an aspect, the invention relates to the method wherein the platelet composition comprises platelet-rich plasma. In an aspect, the invention relates to the method with the proviso that the platelet composition is substantially free from exogenous activators prior to its introduction into and around the region of the incomplete repair in the patient's connective tissue. In an aspect, the invention relates to the method wherein the platelet composition comprises platelets obtained from the patient.

The invention further relates to a method of treating incomplete repair in a patient's connective tissue comprising: obtaining a platelet composition; determining a lesion that comprises the incomplete repair in the patient's connective tissue; and introducing the platelet composition into and around the lesion, with the proviso that substantially no activator is added to the platelet composition prior to its introduction into and around the lesion. The invention also relates to the method wherein the platelet composition is minimally invasively introduced into and around the lesion. The invention also relates to the method wherein the platelet composition comprises platelet-rich plasma. The invention also relates to the method further comprising: mixing into the platelet composition substantially simultaneously with its minimally invasive introduction into and around the lesion one or more of the ingredients selected from thrombin, epinephrine, collagen, calcium salts, and pH adjusting agents. Also useful are materials to promote degranulation or preserve platelets, additional growth factors or growth factor inhibitors, small molecule pharmaceuticals such as NSAIDS, steroids, and anti-infective agents. The invention also relates to the method wherein the patient's connective tissue is selected from: tendons, ligaments, joint capsules, and fascial tissues. The invention also relates to the method wherein introducing the platelet composition into and around the lesion comprises activating platelets in the platelet composition through the action of collagen present in the patient's connective tissue. The invention also relates to the method wherein the platelet composition is at or above physiological pH. The invention also relates to the method wherein the platelet composition comprises platelets obtained from the patient.

In yet another aspect, the invention relates to a composition comprising: platelet releasate wherein the composition is at a pH greater than or equal to physiological pH, and wherein the composition comprises substantially no unactivated platelets.

In a further aspect, the invention relates to a method of treating lesions resulting from acute injury to or chronic disorders of the Medial Collateral Ligament of the knee or elbow, Extensor Carpi Radialis Brevis tendon, Anterior Talofibular Ligament at the ankle, Achilles tendon, posterior tibial tendon, patellar tendon, quadriceps tendon, Anterior Cruciate Ligament, Posterior Cruciate Ligament, spinal ligaments, disc materials, rotator cuff tendon, or biceps tendons comprising: obtaining a platelet composition; determining a location of the lesion; and introducing the platelet composition into and around the lesion, with the proviso that substantially no activator is added to the platelet composition prior to its introduction into and around the lesion. In an aspect, the invention relates to the method wherein the platelet composition is minimally invasively introduced into and around the lesion. In an aspect, the invention relates to the method wherein the platelet composition comprises platelet-rich plasma. In an aspect, the invention relates to the method further comprising: mixing into the platelet composition substantially simultaneously with its minimally invasive introduction into and around the lesion one or more of the ingredients selected from thrombin, epinephrine, collagen, calcium salts, pH adjusting agents. Also useful are materials to promote degranulation or preserve platelets, additional growth factors or growth factor inhibitors, small molecule pharmaceuticals such as NSAIDS, steroids, and anti-infective agents. In an aspect, the invention relates to the method wherein obtaining the platelet composition comprises: drawing blood from a human; and centrifuging the blood to obtain a plasma-rich fraction. In an aspect, the invention relates to the method wherein the platelet composition is at or above physiological pH. In an aspect, the invention relates to the method wherein the platelet composition comprises platelets obtained from the patient.

In a further aspect, the invention relates to a method of treating lesions resulting from injury or chronic disorders of cardiac muscle, skeletal muscle, organ systems, vascular tissue, disc material, spinal bodies, spinal cord, and brain tissue comprising: obtaining a platelet composition; determining a lesion in need of treatment; and minimally invasively introducing the platelet composition into and around the lesion. In an aspect, the invention relates to the method wherein the platelet composition optionally includes platelet releasate. In an aspect, the invention relates to the method further comprising: mixing into the platelet composition one or more of the ingredients selected from thrombin, epinephrine, collagen, calcium salts, and pH adjusting agents. Also useful are materials to promote degranulation or preserve platelets, additional growth factors or growth factor inhibitors, small molecule pharmaceuticals such as NSAIDS, steroids, and anti-infective agents. In an aspect, the invention relates to the method wherein obtaining the platelet composition comprises: drawing blood from a human; and centrifuging the blood to obtain a plasma-rich fraction. In an aspect, the invention relates to the method wherein the platelet composition is at or above physiological pH. In an aspect, the invention relates to the method wherein the platelet composition comprises platelets obtained from the patient.

In an aspect, the invention relates to the method wherein the patient's connective tissue is selected from: tendons, ligaments, joint capsules, and fascial tissues. In an aspect, the invention relates to the method wherein obtaining the platelet composition comprises: drawing blood from a human; and centrifuging the blood to obtain a plasma-rich fraction. In an aspect, the invention relates to the method wherein the platelet composition comprises platelet-rich plasma. In an aspect, the invention relates to the method with the proviso that the platelet composition is substantially free from exogenous activators prior to its introduction into and around the region of the incomplete repair in the patient' damaged or injured tissue. In an aspect, the invention relates to the method wherein the platelet composition comprises platelets obtained from the patient.

The inventive platelet composition may be a biocompatible composition that comprises unactivated platelets, activated platelets, platelet releasate(s), or the like. In an embodiment, the inventive platelet composition comprises platelet-rich plasma (PRP).

The term "PRP" as used herein is a broad term which is used in its ordinary sense and is a concentration of platelets greater than the peripheral blood concentration suspended in a solution of plasma, with typical platelet counts ranging from 500,000 to 1,200,000 per cubic millimeter, or even more. PRP is formed from the concentration of platelets from whole blood, and may be obtained using autologous, allogenic, or pooled sources of platelets and/or plasma. PRP may be formed from a variety of animal sources, including human sources.

Platelets are cytoplasmic portions of marrow megakaryocytes. They have no nucleus for replication; the expected lifetime of a platelet is some five to nine days. Platelets are involved in the hemostatic process and release several initiators of the coagulation cascade. Platelets also release cytokines involved with initiating wound healing. The cytokines are stored in alpha granules in platelets. In response to platelet to platelet aggregation or platelet to connective tissue contact, as would be expected in injury or surgery, the cell membrane of the platelet is "activated" to secrete the contents of the alpha granules. The alpha granules release cytokines via active secretion through the platelet cell membrane as histones and carbohydrate side chains are added to the protein backbone to form the complete cytokine. Platelet disruption or fragmentation, therefore, does not result in release of the complete cytokine.

A wide variety of cytokines are released by activated platelets. Platelet derived growth factor (PDGF), transforming growth factor-beta (TGF-b), platelet-derived angiogenesis factor (PDAF) and platelet derived endothelial cell growth factor (PD-ECGF) and insulin-like growth factor (IGF) are among the cytokines released by degranulating platelets. These cytokines serve a number of different functions in the healing process, including helping to stimulate cell division at an injury site. They also work as powerful chemotactic factors for mesenchymal cells, monocytes and fibroblasts, among others. For the purposes of this patent, the term "releasate" refers to the internal contents of the platelet, including cytokines, which have the potential to affect another cells' function.

Historically, PRP has been used to form a fibrin tissue adhesive through activation of the PRP using thrombin and calcium, as disclosed in U.S. Pat. No. 5,165,938 to Knighton, and U.S. Pat. No. 5,599,558 to Gordinier et al., incorporated in their entirety by reference herein. Activation results in release of the various cytokines and also creates a clotting reaction within various constituents of the plasma fraction. The clotting reaction rapidly forms a platelet gel (PG) which can be applied to various wound surfaces for purposes of hemostasis, sealing, and adhesion.

For instance, PG has been employed to assist with hemostasis in spine surgery and in a rat liver laceration model. One recent investigation showed that use of PG resulted in a significant reduction in post-op narcotic use, a reduction in post-op hemoglobin drop and faster return of functional range of motion after total knee replacement. PG has also been used in wound sealing. One study employed autologous PG as a sealant for craniotomy procedures and noted success in 39 out of 40 patients. PG has further been noted to augment bone healing. One controlled randomized prospective trial of 88 patients revealed a 2 fold increase in radiographic bone maturation and a 50% improvement in histologic bone density when PG was used (Marx, et al., Oral Surg. Oral Med. Oral Path. 1998, vol. 85(6): 638-646). In cardiac and vascular surgery PG is being employed to reduce the incidence of post-op wound dehiscence and infection (Kjaergard, et al., Eur J Cardio-Thoracic Surg. 1996, vol 10: 727-733; Slater, et al., J Ortho Res. 1995, vol 13: 655-663; Sumner et al. J. Bone Joint Surg. (Am) 1995, vol 77:1135-1147; Sethi, et al. Presented at International Society for the Study of Lumbar Spine, June 2001).

However, in none of the above applications and published documents has it ever been disclosed that PRP could be used surgically outside of the context of PG for any purposes other than platelet transfusions to a patient. It is one unique feature of this invention that platelets do not need to be activated prior to their introduction into a patient during the practice of the present invention.

In another embodiment, the inventive platelet composition may comprise releasate from platelets, in addition to platelets themselves. The releasate comprises the various cytokines released by degranulating platelets upon activation. Many activators of platelets exist; these include calcium ions, thrombin, collagen, epinephrine, and adenosine diphosphate. Releasates according to the invention may be prepared according to conventional methods, including those methods described in U.S. Pat. No. 5,165,938 to Knighton, and U.S. Pat. No. 5,599,558 to Gordinier et al.

One disadvantage of conventional releasate strategies associated with the use of PRP as PG is the use of thrombin as a preferred activator. In particular, much thrombin used in PG is bovine thrombin, which can create problems due to contamination issues regarding Creutzfeldt-Jakob disease. Many bovine materials are suspect due to possible prion contamination, and so use of bovine thrombin is disfavored in surgery. Human pooled thrombin is likewise disfavored due to the potential of contamination with various materials such as viruses, prions, bacteria and the like. Recombinant human thrombin might also be used, but is quite expensive.

It is a particular advantage of the present invention that exogenous or extra activators need not be administered to a patient. Collagen, a major component of connective tissues, is a strong activator of platelets. Thus, when the inventive platelet composition is introduced into and/or around connective tissue, platelets in the platelet composition may bind to the collagen and then be activated. This reduces or eliminates the need for administering an exogenous activator such as thrombin. The disadvantages of thrombin use have been noted above. Other strong activators, such as calcium ions, can cause severe pain, unintentional clotting, and other undesirable side effects. Thus, in an embodiment of the invention, no or substantially no exogenous activator is present or added as part of the inventive platelet composition, or is used in the preparation of the inventive platelet composition. Of course, exogenous activators may still be employed if a physician determines that they are medically necessary or desirable.

The platelet composition may be prepared using any conventional method of isolating platelets from whole blood or platelet-containing blood fractions. These include centrifugal methods, filtration, affinity columns, and the like. If the platelet composition comprises PRP, then conventional methods of obtaining PRP, such as those disclosed in U.S. Pat. Nos. 5,585,007 and 5,788,662 both to Antanavich et al., incorporated herein by reference in their entirety, may be utilized.

The platelet-rich plasma composition may be delivered to an individual in need thereof by convention means which include injection using a syringe, catheter, The platelet rich plasma composition may also be delivered via a dermal patch, a spray device or in combination with an ointment, bone graft or drug. It may further be used as a coating on suture, stents, screws, plates or some other implantable medical device. Finally, it may be used in conjunction with a bioresorbable drug or device.

The site of delivery of the platelet-rich plasma composition is at or near the site of tissue injury and/or damage. The site of tissue injury or damage is determined by well-established methods including imaging studies and patient feedback or a combination thereof. The preferred imaging study used is determined by the tissue type. Commonly used imaging methods include, but are not limited to MRI, X-ray, CT scan, Positron Emission tomography (PET), Single Photon Emission Computed Tomography (SPECT), Electrical Impedance Tomography (EIT), Electrical Source Imaging (ESI), Magnetic Source Imaging (MSI), laser optical imaging and ultrasound techniques. The patient may also assist in locating the site of tissue injury or damage by pointing out areas of particular pain and/or discomfort.

Adjusting the pH of platelet compositions has been used to prolong the storage time of unactivated platelets, as disclosed in U.S. Pat. No. 5,147,776 to Koerner. Jr. and U.S. Pat. No. 5,474,891 to Murphy, incorporated by reference herein. pH may be adjusted using a variety of pH adjusting agents, which are preferably physiologically tolerated buffers, but may also include other agents that modify pH including agents that modify lactic acid production by stored platelets. Especially useful are those pH adjusting agents that result in the pH of the platelet composition becoming greater than or equal to physiological pH. In an embodiment, the pH adjustment agent comprises sodium bicarbonate. Physiological pH, for the purposes of this invention, may be defined as being a pH ranging from about 7.35 to about 7.45. pH adjusting agents useful in the practice of this invention include bicarbonate buffers (such as sodium bicarbonate), calcium gluconate, choline chloride, dextrose (d-glucose), ethylenebis(oxyethylenenitrilo)tetraacetic acid (EGTA), 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES), maleic acid, 4-morpholinepropanesulfonic acid (MOPS), 1,4-piperazinebis(ethanesulfonic acid) (PIPES), sucrose, N-tris(hydroxymethyl)methyl-2-aminoethanesulfonic acid (TES), tris(hydroxymethyl)aminomethane (TRIS BASE), tris(hydroxymethyl)aminomethane hydrochloride (TRIS.HCl), and urea. In a preferable embodiment, the pH adjusting agent is a bicarbonate buffer, more preferably, sodium bicarbonate.

For the purposes of this patent, the term "tissues" includes but is not limited to cardiac and skeletal muscle, disc material, vertebral bodies, internal organs, brain and spinal cord tissue, vascular tissue such as arteries and veins and non-differentiated tissue.

For the purposes of this patent, connective tissues comprise tendons, ligaments, fascial tissues, and joint capsules. In a preferable embodiment, connective tissues comprise the Medial Collateral Ligament of the knee or elbow, Extensor Carpi Radialis Brevis tendon (tennis elbow), Anterior Talofibular Ligament at the ankle, Achilles tendon, Anterior Cruciate Ligament, Posterior Cruciate Ligament, posterior tibial tendon, patellar tendon, quadriceps tendon, rotator cuff tendon, and biceps tendons.

Incomplete repair, as it is used in the context of this patent application, may be defined to mean repair that is disorganized, substantially non-existent (such as in the case of an unhealed tear), or otherwise pathological. Disorganized repair is characterized by a disorganized angiofibroblastic dysplasia, with degenerative, immature and avascular tissue. Such tissue is weaker than normal connective tissue and lacks the strength to function normally. This tissue also limits the patient by causing pain and negatively impacting the patient's quality of life. Substantially non-existent repair might occur in a situation where a connective tissue is torn and does not heal properly subsequently to the tear. Otherwise pathological repair may be any other type of repair in which the tissue is not repaired to be substantially the same as the tissue was before tissue repair was necessary.
 

Claim 1 of 7 Claims

1. A method of treating myocardial infarction in an individual comprising: determining a site of dysfunctional cardiac muscle in the individual; titrating a platelet-rich plasma composition to obtain a pH of about 7.3 to 7.5; and introducing the platelet-rich plasma composition via a catheter into and around the site of dysfunctional cardiac muscle, wherein no exogenous activator is added to the composition prior to its introduction into and around the site of dysfunctional cardiac muscle thereby treating myocardial infarction.

____________________________________________
If you want to learn more about this patent, please go directly to the U.S. Patent and Trademark Office Web site to access the full patent.

 

 

     
[ Outsourcing Guide ] [ Cont. Education ] [ Software/Reports ] [ Training Courses ]
[ Web Seminars ] [ Jobs ] [ Consultants ] [ Buyer's Guide ] [ Advertiser Info ]

[ Home ] [ Pharm Patents / Licensing ] [ Pharm News ] [ Federal Register ]
[ Pharm Stocks ] [ FDA Links ] [ FDA Warning Letters ] [ FDA Doc/cGMP ]
[ Pharm/Biotech Events ] [ Newsletter Subscription ] [ Web Links ] [ Suggestions ]
[ Site Map ]