b.tuch@unsw.edu.au

Diabetes Transplant Unit Prince of Wales Hospital

Type 1 diabetes, a disorder affecting 130,000 young Australians, is caused by the autoimmune destruction of insulin-producing (ß) cells in the pancreas.  Cell therapies are being developed to replace the destroyed ß cells. Such therapies being examined in the Diabetes Transplant Unit include the development of stem cells, transdifferentiation of liver cells, insulin-producing cells isolated from donor adult human pancreases, human fetal pancreatic tissue and pancreatic cells isolated from pigs.   The projects being offered to Honours students for 2007 are developmental projects with pig cells, fetal tissue and embryonic stem cells. 

Project 1:  Encapsulated insulin-producing pig cells as a therapy for diabetes

Co-supervisor:  Jayne Foster  (jaynef@student.unsw.edu.au)

A technique being used in the Diabetes Transplant Unit to prevent immune rejection of cells once transplanted is to place them inside microcapsules made of a product from seaweed, barium alginate.  Experiments conducted in the Unit have shown that encapsulated insulin-producing fetal pig cells implanted in diabetic immunodeficient mice mature and function with normalization of blood sugar levels.  Insulin-producing mouse cells also normalize blood sugar levels when implanted in immunocompetent mice.  However, when the insulin-producing pig cells are transplanted into immunocompetent mice, an inflammatory response occurs and the implanted cells do not function.  This Honours project is designed to analyse the nature of the inflammatory response, such as measurement of cytokines, chemokines, heat shock proteins and immune cells.  If time permits, a strategy to induce the grafted pig cells to function also will be developed.

Selected References (Available on request)

• Dean et al.   Transplantation 2006, in press (encapsulation)

• Vo et al Transplantation 2001; 71: 1671-7

Program 2:  :  Isolation and culture of oocytes from human fetal ovarian tissue 

Co-Supervisors: Dr Kuldip Sidhu (k.sidhu@unsw.edu.au) & Lindy Williams (l.williams@unsw.edu.au)

The project is designed to isolate immature oocytes from human fetal ovarian tissue and determine the feasibility of maturing them in culture.  It is possible that such eggs might be used at some future time in Assisted Reproductive Technology.  The project requires tissue culture, immunohistochemistry ± molecular biological techniques.  It will parallel another project being carried out in the Diabetes Transplant Unit attempting to differentiate human embryonic stem cells into oocytes.

Selected References (Available on request)

• Mavroforou et al  Human Reproduction & Genetic Ethics; 2005; 11: 6-11

• Tuch et al Med J Aust 2003; 179: 547-50

Program 3: Human embryonic stem cell integrin expression profile

Co-supervisor:   Justin Lees (justin.lees@student.unsw.edu.au)

An exciting strategy being examined at the Diabetes Transplant Unit involves the potential directed differentiation of human embryonic stem cells (hESCs) into insulin producing ß-cell surrogates. To achieve this objective we have incorporated 3D cell culturing and tissue engineering. We are interested not only in directing the hESCs to differentiate into insulin producing cells but also inducing them to function in a 3D environment that is reminiscent of the structure of a pancreatic islet. Effective function in a 3D environment involves appropriate cellular adhesion to the surface of a complex tissue engineered structure. The integrin expression profile of a cell plays an important role in determining whether or not it will adhere particular surfaces. The aim of this project is to describe the integrin expression profile of hESCs at various stages of differentiation along the pathway to producing ß-cell surrogates. Integrin expression profiles will be assessed by real time PCR, FACS and immunofluorescent staining.

Selected References (Available on request)

• Anderson et al Nat Biotech 2004; 22: 863-6

• Levenberg et al.  Proc Natl Acad Sci 2003; 100: 12741-6