Method of tissue vascularization

Abstract

Methods are disclosed to promote vascularization of tissue in mammals using an autologous platelet-rich plasma composition. The methods are useful for vascularizing tissue with a compromised blood supply, particularly cardiac tissue with a compromised blood supply due to heart attack or congestive heart failure.

Description

RELATED APPLICATIONS[0001]This application is a continuation of U.S. application Ser. No. 11 / 085,987, filed Mar. 22, 2005 which claims priority under 35 U.S.C. § 119(e) to provisional application No. 60 / 655,668 filed Feb. 23, 2005 and is a continuation-in-part of U.S. application Ser. No. 10 / 941,124, filed Sep. 15, 2004 which is a continuation of U.S. application Ser. No. 10 / 412,821, filed Apr. 11, 2003, now U.S. Pat. No. 6,811,777, which claims priority under 35 U.S.C. § 119(e) to U.S. Provisional Application No. 60 / 372,682, filed Apr. 13, 2002. All of the above are incorporated by reference in their entirety.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]Embodiments of the invention are directed to methods and kits for the treatment of damaged tissue in a human or non-human animal using autologous platelet-rich plasma. In a preferred embodiment, methods and kits are described for the treatment of lateral epicondylitis, plantar fasciitis, and rotator cuff injury.[0...

AI Technical Summary

Benefits of technology

[0062]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, intentional 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.

[0063]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.

[0064]The platelet-rich plasma composition may be delivered to an individual in need thereof by conventional means which include injection using a syringe or 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.

[0065]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.

[0066]Adjusting the pH of platelet compositions has been used to prolong the storage time of unactivated platelets, as disclosed in U.S. Pat. Nos. 5,147,776 to Koerner, Jr. and 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 6.5-8.0, more preferably from 7.3 to 7.5, yet more preferably 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), monobasic phosphate, 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES), maleic acid, 4-morpholinepropancsulfonic acid (MOPS), 1,4-piperazinebis(ethanesulfonic acid) (PIPES), 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.

[0067]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.

Problems solved by technology

Injuries or other damage to flexible, relatively avascular connective tissues (hereafter “connective tissue” or “connective tissues”) are known to take a very long time to heal (months or even years).

In many cases, injuries to connective tissues may never heal properly, necessitating surgical intervention.

Tendinosis is an accumulation over time of small-scale injuries that don't heal properly; it is a chronic injury of failed healing.

Tendinosis can result from repetitive activities such as playing sports, using computers, playing musical instruments, or doing manual labor.

The body attempts to repair these microtears but the healing process is incomplete in many cases.

This incomplete attempt at repair results in degenerative, immature and avascular tissue.

Incompletely repaired tissue is weaker than normal tendon 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.

Unfortunately, plantar fasciitis usually takes many months to resolve.

Rest and activity modification may help patients with some of these conditions, but there remains a significant clinical population that are not reachable with these therapies.

Despite widespread use, oral anti-inflammatory medications have not proven to be useful in controlled studies.

Some studies further suggest that non-steroidal medication may actually have an adverse effect on the healing process for ligament injuries.

Cortisone injections are frankly controversial in the treatment of tendinoses and are contraindicated in acute ligament injuries.

Results beyond one year, however, reveal a high symptom recurrence rate and only an equivocal efficacy rate.

These injections also carry the risk of tendon rupture, infection, skin depigmentation, subdermal atrophy and hyperglycemia in diabetic patients.

Physical therapy is commonly used, but expensive and it is not clear that such treatment is helpful (Smidt 2003).

Furthermore, the average cost is high: $1200-1500.

However, open or arthroscopic surgery has many potential complications such as deep infection, damage to neurovascular structures, and scar formation.

The surgery is also expensive and carries the additional risks associated with regional or general anesthesia.

None of the prior art teach treatment of connective tissue with PRP to promote tissue repair.

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