Chemistry: molecular biology and microbiology – Maintaining blood or sperm in a physiologically active state...
Reexamination Certificate
2000-02-10
2001-08-28
Reamer, James H. (Department: 1614)
Chemistry: molecular biology and microbiology
Maintaining blood or sperm in a physiologically active state...
C435S325000, C436S018000
Reexamination Certificate
active
06280925
ABSTRACT:
FIELD OF INVENTION
This invention relates to the field of blood vessel and vascularized organ grafts, and more particularly, to a composition and methods for use of the composition in the treatment of vascular graft segments prior to cryopreservation, storage and transplantation.
BACKGROUND
Autogenous veins or arteries are the most common and most preferred conduits in revascularization of coronary and peripheral occlusive vascular disease. With the increasing age of the population and the increasing number of redo operations due to the development of intimal hyperplasia (an increase in the size of a tissue or organ due to an increase in the number of component cells) and accelerated atherosclerosis (obstruction of the arteries by localized fatty deposits) in bypass grafts, it is expected that over one third of patients will not have one or both of these conduits available at the time of revascularization. Prosthetic materials can be used for large diameter vessels; however their patency (state of being open or unblocked) is poor when used as conduits to replace small diameter vessels. There is, therefore, a need for alternative conduits, particularly for smaller diameter vessels. Cryopreserved arterial and venous allografts have been suggested as a possible “off-the-shelf” solution for small diameter vessel bypass. Clinical studies of these gmfts have been limited in both coronary and peripheral circulation, but demonstrate the significant stigma of poor patency irrespective of position.
Blood vessels are also a ubiquitous component of human vascularized tissues and organs, which may, one day, be successfully stored by cryopreservation for transplantation. Furthermore, providing that significant immunological issues can be overcome, cryopreserved xenografts may, one day, provide an unlimited supply of vascularized tissues and organs for storage by cryopreservation.
Although not commonly employed, polyethylene glycol (PEG) has been reported to be a cryopreservation agent (see “Pharmcological Considerations in Cryopreservation” by Shlafer in Organ Preservation for Transplantation, Karow AM and Pegg DE (eds) Marcel Dekker, New York, pp 177-212 (1981)). It has also been suggested that PEG may reduce the immune response to allogeneic blood transfusions and transplants (see “Molecular Camouflage of Antigenic Determinants on Intact Mammalian Cells: Possible Applications to Transfusion Medicine” by Murad et al. in Blood 88 (Supplement 1): 1765 (1996); “The Other Blood Substitute: Antigenically Inert Erythrocytes” by Scott et al.; and “Heart Preservation Solution Containing Polyethylene Glycol: An Immunosuppressive Effect” by Collins et al. in Lancet, 338:390 (1991)). A 30% reduction has been observed in the incidence of acute rejection in a group of heart transplant recipients in which the donor organ had been stored at 4° C. in a solution containing 5%. In a subsequent study, PEG produced a modest but statistically significant increase in rat liver allograft survival time from 9.6 to 11.9 days (see “The Immunosuppressive Effect of Polyethylene Glycol in a Flush Solution for Rat Liver Transplantation” by Tokunaga et al. in Transplantation 54:756-8 (1992)). In these studies, the transplanted organ was merely soaked in the PEG solution without subsequent cryopreservation.
U.S. Pat. No. 4,938,961 to Collins et al. discloses an organ preservation solution containing polyethylene glycol, along with a variety of further ingredients including: 30-40mM NaOH, 100 mM Lactobionic acid, 25 mM KH2PO4, 10 mM KOH, 30 mM raffinose, and 3 mM glutathione. This solution is used for the transport of an organ from a donor to a recipient in cold solution.
In recent unpublished studies, it was found that the development of intimal hyperplasia in cryopreserved allografts is accelerated compared to fresh allografts due to the additional cryopreservation insults superimposed on the melee of other variables associated with the placement of veins into the arterial circulation.
Cryopreserved allografts have been shown to have extensive medial fibrosis, intnnal hyperplasia and a significant infiltrate consisting of activated macrophages, lymphocytes, granulocytes and plasma cells (see “Transplantation of Cryopreserved Canine Venous Allografts” by Bank et al. in J Surg Res 50:57-64 (1991), “Cryopreserved Venous Homografts as Vascular Conduits in Canine Carotid Arteries” by Showalter et al. in Surgery 106:652-659 (1989), “Evaluation of Cryopreserved Allograft Venous Conduits in Dogs” by Deaton et al. in J Thorac Cardiovasc Surg 103:153-162 (1992) and “A study of the Functional and Histological Differences in Autologous and Allogenic Vein Grafts-Two Different Vasculopathies” by Davies et al. in J Surg Res 69:14-22 (1997)).
SUMMARY OF THE INVENTION
According to the present invention, a new composition, which includes both polyethylene glycol (PEG) and an antioxidant, such as glutathione (GSH), may be used to treat vascular grafts prior to cryopreservation and transplantation to ameliorate the onset of intimal hyperplasia, which would otherwise occur after vascular graft cryopreservation and transplantation. The PEG and GSH containing composition may be incorporated into a transport or other processing solution employed for the vascular grafts prior to their cryopreservation. The vascular grafts are preferably contacted with the composition containing PEG and GSH for at least the 12 hours prior to cryopreservation.
REFERENCES:
patent: 4938961 (1990-07-01), Collins et al.
patent: 5599659 (1997-02-01), Brasile et al.
patent: 5834509 (1998-11-01), Malfroy-Camine et al.
patent: 6007978 (1999-12-01), Goodrich et al.
patent: 6127181 (2000-10-01), Kadkade
patent: WO 01/01774 A1 (2001-01-01), None
Collins et al (II), Lancet, vol. 338, pp. 890-891, Oct. 1991.*
O'Neil et al, Crylbioligy; vol. 34, pp. 295-301, 1997.*
Bryan et an, Chest, vol. 100 , pp. 1694-1702 (abstract), Dec. 1991.*
Ohboshi et al, Anim, Reprod. Sci., vol. 48, pp. 27-36 (abstract), Jul. 1997.*
Davies et al, Eur. J. Vasc. Endovasc. Surg., vol. 17, pp. 493-500 (abstract), Jun. 1999.*
K. Murad, et al., “Molecular Camouflage of Antigenic Determination on Intact Mammalian Cells: Possible Applications to Transfusion Medicine,”Blood88 (Supplement 1) 1765, p. 444a (1996).
A. Collins, et al., “Heart preservation solution containing polyethyleneglycol: an immunosuppressive effect?, ”The Lancet338, pp. 890-891 (1991).
D. Deaton, et al., “Evaluation of cryopreserved allograft venous conduits in dogs,”The Journal of Thoracic and Cardiovascular Surgery103, No. 1, pp. 153-162 (1992).
M. Davies, et al., “Functional and Histological Differences in Autogenous and Allogenic Vein Grafts: Two Different Vasculopathies?,”Journal of Surgical Research69, Article No.JR975019, pp. 14-22 (1997).
M. Scott, et al.,The Other Blood Substitute: Antigenically Inert Erythrocytes, pp. 133-150.
M. Schlafer, “Pharmacological Considerations in Cryopreservation,”Organ Preservation for Transplantation (2ndEdition), Marcel Dekker, Inc., New York, pp. 177-212 (1984).
J.M. Malone, et al., “Venous Cryopreservation: Endothelial Fibrinolytic Activity and Histology,”Journal of Surgical Research29, pp. 209-222 (1980).
Y. Tokunaga, et al., “The Immunosuppressive Effect of Polyethylene Glycol In A Flush Solution For Rat Liver Transplantation,”Transplantation54, No. 4, pp. 756-758 (1992).
D. Showalter, et al., “Cryopreserved venous homografts as vascular conduits in canine carotid arteries,”Surgery106, No. 4, pp. 652-659 (1989).
N. Augelli, et al., “Allograft Vein Patency In A Canine Model,”Transplantation52, No. 3, pp. 446-470 (1991).
J. Elmore, et al., “Functional changes in canine saphenous veins after cryopreservation,”International Angiology11, No. 1, pp. 26-35 (1992).
H. Bank, et al, “Transplantation of Cryopreserved Canine Venous Allografts,”Journal of Surgical Research50, pp. 57-66 (1991).
OIiff & Berridge, PLC
Organ Recovery Systems, Inc.
Reamer James H.
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