A Preclinical Model Of Pig Islet Xenotransplantation As Treatment For Type 1 Diabetes
Funder
National Health and Medical Research Council
Funding Amount
$4,380,000.00
Summary
The object of this multi-disciplinary program grant is to develop a source of pig insulin secreting tissue that will be used to treat type 1 diabetic patients. At present the number of diabetic patients that would benefit from islet transplantation far outnumber any human source of this tissue. Pigs that have been genetically altered to avoid rejection and enhance survival could overcome this donor shortage problem.. It is our belief that with the appropriate genetic modification pig insulin-sec ....The object of this multi-disciplinary program grant is to develop a source of pig insulin secreting tissue that will be used to treat type 1 diabetic patients. At present the number of diabetic patients that would benefit from islet transplantation far outnumber any human source of this tissue. Pigs that have been genetically altered to avoid rejection and enhance survival could overcome this donor shortage problem.. It is our belief that with the appropriate genetic modification pig insulin-secreting tissue can avoid the aggressive rejection response that occurs with xenographs and provide normal blood glucose control without insulin. This project concentrates on the five main issues that need to be overcome before pig insulin-secreting tissue can be used in diabetics. These are: identifying the best source of insulin secreting tissue to use; adult islets, newborn or foetal islet cell clusters; overcoming the strong rejection response to pig tissue; identifying a safe and effective immunosuppressive regime; producing a new types of genetically modified pigs that will provide islets tissue that will work in humans; and demonstrating that pig islet transplantation will not pose undue infective risks for the patient or community. This truly collaborative program grant has brought together a large group of investigators with strong research records in diabetes, islet transplantation, xenotransplantation, pig transgenesis and pig genetics and includes scientists and clinicians who look after diabetic patients. Unique pig resources will be used including genetically manipulated pigs that have been shown to avoid some of the rejection mechanisms associated with transplanting pig tissue. There is a captive-bred baboon colony that provided a unique model of diabetes. A world class pig transgenesis facility has been enlisted to generate new lines of genetically altered pigs as new data is produced within the group. Finally because of the involvement of the National Pancreas Transplant Unit any proven therapeutic strategy can be brought quickly to clinical trials.Read moreRead less
Determination Of Irradiation Dose Efficacy For Use In Impaction Grafting At Revision Joint Replacement
Funder
National Health and Medical Research Council
Funding Amount
$411,517.00
Summary
Primary hip replacement is a successful intervention for hip disease, but 10-15% of hip prostheses fail and require revision surgery within 10-15 years. At the time of revision, significant bone loss around the failed prosthesis is not uncommon. A bone reconstruction procedure, called impaction grafting, where donor bone is minced and placed in the areas of deficient bone before implanting the new prosthesis, has shown to give good results at more than ten years in some centres. A high incidence ....Primary hip replacement is a successful intervention for hip disease, but 10-15% of hip prostheses fail and require revision surgery within 10-15 years. At the time of revision, significant bone loss around the failed prosthesis is not uncommon. A bone reconstruction procedure, called impaction grafting, where donor bone is minced and placed in the areas of deficient bone before implanting the new prosthesis, has shown to give good results at more than ten years in some centres. A high incidence of early complications of this procedure have included loss of fixation within the bone. Fracture of the bone around prostheses has also reported in some centres. These events require more surgery, putting the patient at higher risk greater complications and longer rehabilitations. Recent improvements in surgical technique and donor bone preparation have improved results. A current debate questions whether the dose of irradiation can be reduced from 25 kGy, while maintaining sterility of allografts. The risk of bacterial contamination in allografts is low, and irradiation reduces the mechanical strength of the graft, contributing to complications when irradiated bone is used. The benefits of decontaminating the bone may be outweighed by the higher risk for failure due to poor bone quality and resulting prosthesis instability. We will use ISO standards to test the validity of radiation dose for sterilising bone ex vivo. In the absence of controlled human studies, our aim is also to compare the results of impaction grafting with non-irradiated bone versus bone irradiated at current doses used by Australian bone banks, and lower doses indicated by ex vivo testing. We will use a large animal model of revision hip replacement, with precise measures of prosthesis stability. The results of this study will guide clinical decisions regarding the efficacy of current bone graft preparation procedures and the use of irradiated bone in human hip replacement surgery.Read moreRead less