| Method for preserving organs for transplantation -> Monitor Keywords |
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Method for preserving organs for transplantationRelated Patent Categories: Chemistry: Molecular Biology And Microbiology, Differentiated Tissue Or Organ Other Than Blood, Per Se, Or Differentiated Tissue Or Organ Maintaining; Composition ThereforMethod for preserving organs for transplantation description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20080070229, Method for preserving organs for transplantation. Brief Patent Description - Full Patent Description - Patent Application Claims
CLAIM OF PRIORITY [0001] The present application is a divisional application of U.S. patent application Ser. No. 10/338,949, filed Jan. 8, 2003, incorporated in its entirety by reference herein, and which claims priority under 35 U.S.C. .sctn.119(e) to U.S. Provisional Application Nos. 60/347,171, filed Jan. 9, 2002, and 60/353,639, filed Jan. 31, 2002, the entireties of which are hereby incorporated by reference. FIELD OF THE INVENTION [0002] The present invention relates to apparatus and methods for preserving tissue, such as harvested organs for transplant. BACKGROUND OF THE INVENTION [0003] Over the past thirty years, solid organ transplantation has become an increasingly viable treatment option for a variety of diseases and conditions. For example, in the United States alone, kidney transplants are now performed at an annual rate of over 9,000, and heart transplants are performed at the rate of over 1,500 per year. However, rejection of the transplanted tissue due to the recipient's normal immune response and transplant-related pathophysiology in the graft tissue continues to be a major hurdle to successful transplantation. In particular, graft tissue quality is a major factor underlying graft rejection. The method of storing a donor organ once removed from the donor greatly impacts. [0004] Typically, once a donor organ is harvested, the organ is preserved by storage in a portable hypothermic container under sterile conditions. Thus, methods to preserve donor tissue integrity have focused primarily on maintenance of properly hypothermic and sterile conditions. However, tissue integrity compromised after harvesting and during storage remains a barrier to improved long-term survival of organ transplants. Even under carefully monitored hypothermic and sterile conditions, ischemia and reperfusion injury negatively impact donor tissue quality. In particular, ischemic damage to the vascular endothelium can result in accelerated graft atherosclerosis, which adversely affects ultimate survival of the graft. In addition, compromised donor tissue contributes to other chronic pathologies in the graft that result in substantial rates of graft loss. [0005] The problem of compromised organ tissue integrity is a major factor contributing to inadequate supplies of organs for transplant. About one in four patients awaiting cardiac transplantation dies while waiting for a suitable donated heart, and similar supply problems plague candidate recipients of other organs. The waits are due in part to insufficient rates of organ donation from potential donors, but also due in part to insufficient progress in developing successful techniques for preserving donated organs beyond very limited time periods after harvesting. Recent advances in immunosuppressive therapy that otherwise after harvesting. Recent advances in immunosuppressive therapy that otherwise have made organ transplantation more feasible have merely exacerbated the problems of organ supply. Thus, a major hurdle in exploiting improved organ transplantation techniques has been the inability to extend safe preservation of donated organs beyond the currently accepted time limit of about four hours. Preservation time limits of a few hours effectively limit the geographic area within which a donated organ can be transported and still be successfully transplanted. Such time limits also make it difficult or impossible to meaningfully evaluate the donated organ before transplant. [0006] Known organ preservation approaches typically include hypothermic arrest and storage in a liquid medium or perfusate, such as known cardioplegic preservation solutions for hypothermic preservation of donated hearts. However, such approaches still do not prevent myocardial damage due to ischemia, reperfusion, fluid and electrolyte imbalances leading to edema, and metabolic exhaustion at the cellular level leading to a degradation of high-energy phosphates, all known to be factors contributing substantially to tissue damage. [0007] To avoid the problems associated with hypothermic arrest and storage, it is known in the art that normothermic preservation eliminates the need to arrest organ function and the need for hypothermic storage, and reduces reperfusion injury and other time dependent tissue injury associated especially with metabolic rundown and depletion of high-energy phosphates. Thus, known methods for extending organ preservation involve attempts to simulate near-normal physiologic conditions, using various approaches. One approach involves harvesting almost all the donor's organs and using the system to perfuse the needed organ under normothermic conditions. However, as an element of routine transplant practice, this approach is limited because of the myriad practical difficulties involved in removing and preserving heart, lungs, liver, pancreas, and kidneys all together and all in functioning condition. Another related approach to achieving extended extracorporeal preservation of a donor organ involves providing continuous sanguineous perfusion, while maintaining the donor organ in the normal functioning state. Thus, known approaches include apparatus, methods and physiologic media that create an extracorporeal circuit for sanguineously perfusing the harvested organ at normothermic temperatures, thus prolonging preservation of the harvested organ for up to about twenty-four hours or longer. However, such approaches remain relatively cumbersome, are relatively costly, are not readily amenable to transport because they involve fairly complex perfusion systems, and have met with limited success. [0008] In the field of surgery, high-energy laser radiation is now well accepted as a surgical tool for cutting, cauterizing, and ablating biological tissue. High-energy lasers are now routinely used for vaporizing superficial skin lesions and, and to make deep cuts. For a laser to be suitable for use as a surgical laser, it must provide light energy at a power sufficient to heat tissue to temperatures over 50 C. Power outputs for surgical lasers vary from 1-5 W for vaporizing superficial tissue, to about 100 W for deep cutting. [0009] In contrast, low level laser therapy involves therapeutic administration of laser energy to a patient at vastly lower power outputs than those used in high energy laser applications, resulting in desirable biostimulatory effects while leaving tissue undamaged. For example, in rat models of myocardial infarction and ischemia-reperfusion injury, low energy laser irradiation reduces infarct size and left ventricular dilation, and enhances angiogenesis in the myocardium. (Yaakobi et al., J. Appl. Physiol. 90, 2411-19 (2001)). Low level laser therapy has been described for treating pain, including headache and muscle pain, and inflammation. The use of low level laser therapy to accelerate bone remodeling and healing of fractures has also been described. (See, e.g., J. Tuner and L. Hode, Low LEVEL LASER THERAPY, Stockholm:Prima Books, 113-16, 1999, which is herein incorporated by reference). [0010] However, known low level laser therapy methods are circumscribed by setting only certain selected parameters within specified limits. For example, known methods are characterized by application of laser energy at a set wavelength using a laser source having a set power output. Specifically, known methods are generally typified by selecting a wavelength of the power source, setting the power output of the laser source at very low levels of 5 mW to 100 mW, setting low dosages of at most about 1-10 Joule/cm.sup.2, and setting time periods of application of the laser energy at twenty seconds to minutes. However, other parameters can be varied in the use of low level laser therapy. In particular, known low level laser therapy methods have not addressed the multiple other factors that may contribute to the efficacy of low level laser therapy. [0011] Against this background, a high level of interest remains in finding new and improved methods for preserving harvested organs for transplant thus to extend the time period for preservation. A need thus remains for simple, portable and cost-effective apparatus and methods that provide the ability to extend the organ preservation period beyond accepted limits, while avoiding time-dependent tissue damage due to ischemia and reperfusion, and depletion of high-energy phosphates. A need also remains for apparatus and methods that help to overcome organ transplant rejection, and enhance the survival time of transplanted organs, by improving the tissue quality of transplanted organs. SUMMARY OF THE INVENTION [0012] The light therapy apparatus and methods for preserving tissue, including organs, for transplant are based in part on the new and surprising discovery that applying electromagnetic energy to the tissue during transport, generally following explantation, appears to prevent or retard tissue damage in a harvested organ, thus extending the time period of preservation and helping to overcome transplant rejection by improving tissue quality in preserved organs. Preferably the electromagnetic energy that is applied falls within a select wavelength range and at a select range of power density (i.e., power per unit area) [0013] In accordance with one embodiment, there is provided an apparatus for transporting living tissue, such as an organ, comprising a tissue preserving container having an interior cooling chamber adapted to receive a tissue, and at least one light source mounted on the container so as to illuminate the interior cooling chamber from a multiplicity of directions, where said light source emits optical radiation which produces a biostimulative effect on a tissue, thereby preventing or retarding damage to said tissue during transport. [0014] Thus, one preferred method relates to preserving organs for transplant and includes delivering to a harvested organ an effective amount of electromagnetic energy, the electromagnetic energy having a wavelength in the visible to near-infrared wavelength range, wherein delivering the effective amount of electromagnetic energy comprises selecting a predetermined power density of electromagnetic energy. The electromagnetic energy is applied to harvested organs placed in a preservation medium or perfusate, and may be applied in a hypothermic environment, for example in a hypothermic container or chamber, or in a normothermic environment. In a preferred embodiment, the power density is selected to be about 0.01 mW/cm.sup.2 to about 100 mW/cm.sup.2. To deliver the predetermined power density of electromagnetic energy to the organ, such method may further include selecting a power and dosage of the electromagnetic energy sufficient to deliver the predetermined power density of electromagnetic energy to the organ. The electromagnetic energy is then applied to multiple treatment points across the organ surface. [0015] The methods are particularly suitable for preserving solid organs for transplant such as heart, lung, kidney, liver, or pancreas, but may also be used to preserve other tissues or organs. [0016] The methods are further directed toward preventing or retarding rejection of a transplanted organ in a subject in need thereof, the method including delivering to a harvested organ before transplant into the subject an effective amount of electromagnetic energy wherein delivering the effective amount of electromagnetic energy comprises selecting a power density of the electromagnetic energy, preferably about 0.01 mW/cm.sup.2 and less than about 100 mW/cm.sup.2. [0017] In one embodiment, an apparatus for preserving tissue, such as a harvested organ for transplant includes a media storage container and a primary cover which mates with the media storage container to form a fluid-tight seal. The media storage container has a base and side walls extending from the base, and the side walls have a plurality of openings therethrough, each opening configured to mate with an electromagnetic energy source, such as a laser energy source, to form a fluid tight seal. The media storage container is configured to suspend the harvested organ in a fluid preservation medium. The media storage container is suspended in a secondary container having a base and side walls extending therefrom, the secondary container configured to suspend the media storage container in a thermoregulatory fluid. A plurality of electromagnetic energy sources extend from the side walls, each electromagnetic energy source mating with one of the plurality of openings on the media storage container side walls to form a fluid tight seal against the thermoregulatory fluid. A secondary cover mates with the secondary container. The electromagnetic energy sources are configured to emit electromagnetic energy having a wavelength in the visible to near-infrared wavelength range at a power density selected from the range of about 1 mW/cm.sup.2 to about 100 mW/cm.sup.2. The apparatus is used to apply electromagnetic energy at a selected power density to a harvested organ suspended in a preservation medium in the media storage container. BRIEF DESCRIPTION OF THE DRAWINGS [0018] The FIGURE is a perspective view of one embodiment of an apparatus for transporting tissue, such as an organ. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Continue reading about Method for preserving organs for transplantation... Full patent description for Method for preserving organs for transplantation Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Method for preserving organs for transplantation patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. 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