A study of the factors which may influence the isolation of porcine islets of Langerhans
thesisposted on 15.12.2014 by Steven A. White
In order to distinguish essays and pre-prints from academic theses, we have a separate category. These are often much longer text based documents than a paper.
Pancreas transplantation is a major surgical procedure with a high morbidity and mortality, whereas an islet transplant can be performed under a local anaesthetic and is much less invasive. With the current worldwide shortage of human organ donors, investigators have been forced to seek an alternative source of donor tissue. One such source could be the porcine pancreas, but porcine islet isolation is well known to be extremely variable. The object of this thesis was to improve upon some of the current methods of porcine islet isolation and to identify some of the reasons for its variability.;One of the most important factors effecting islet isolation is the number of islets within the pancreas and this was assessed using computer image analysis and demonstrated significant differences between pancreata in terms of the percentage CSSA density. A large proportion of the work for this thesis was committed to the collagenase digestion phase of porcine pancreata. Part of this work was to develop a cold storage solution (ULEIC), specifically for porcine islet isolation. I also looked at the distribution of the collagen substrate (Types, I, III, IV, V and VI) within the pancreas though no differences were apparent between pancreata, but collagen type VI was the most predominant throughout. Furthermore, it is feasible that the pancreas is also digested by endogenous pancreatic enzymes released during the dispersion phase, as well as by collagenase, but little is known of their activation within the digestion circuit. Again, this showed extreme variability between isolations. Lastly, if porcine islet isolation were to be routinely used for xenotransplantation, there are many concerns over the infective potential of porcine islets, but this can be minimised by using specific antibiotic regimens and careful aspectic isolation techniques. Overall there are many factors limiting porcine isolation, the reason for its variability appears to be multifactorial.