Standardization of Isolation Procedure and Analysis of Variables on Successful Isolation of Islet from the Human Pancreas / 대한내분비학회지

BACKGROUND: Identifying the donor and isolation-related factors during the islet isolation would be greatly helpful to improve the result of human islet isolation for successful clinical islet transplantation. METHODS: Sixty-nine pancreata from cadaveric donors were isolated with standard protocol and analyzed to identify the donor factors and isolation variables for successful isolation. Islet isolations recovered > or = 100,000 Islet Equivalent (IEQ, n=53) were compared to islet mass less than 100,000 IEQ (n=16). RESULTS: The mean islet recovery was 216.0 x 10(3) +/- 173.7 x 10(3) (IEQ) before purification and 130.6 x 10(3) +/- 140.2 x 10(3) (IEQ) after purification. Mean purity was 54 +/- 31%. Mean age of donor was 31.2 +/- 13.2 year and mean cold ischemic time was 6.9 +/- 6.2 hour. Quality of isolated islets was acceptable in terms of bacterial culture, viability and secretory function in vitro and in vivo. In univariate analysis on successful isolation, status of pancreas was the only significant factor and sex, duration of collagenase expansion and digestion time were marginal factors. Stepwise multivariate logistic regression analysis showed donor sex, status of pancreas and digestion time were significant factors for the successful islet isolation. CONCLUSION: This study confirms some donor factors and variables in isolation process can influence the ability to obtain the successful isolation of human islet. Enough experiences and pertinent review of donor and isolation factors can make islet isolation successful, supporting the clinical islet transplantation without spending of cost.

Experimental Study on Cryopreservation of Pancreas Islet Cell in Rat / 대한이식학회지

PURPOSE: Cryopreservation of pancreas islet cells can facilitate the clinical islet transplantation by giving a means of storage of islets and immunomodulation on pancreatic islet preparations. METHODS: Pancreatic islets were isolated by standard technique using collagenase in rat. Cryopreservation was performed by using DMSO as a cryoprotectant after one day or 48 hr culture. Recovery rate, viability and insulin release in assay in vitro and vivo were checked under the various conditions, such as concentration of DMSO (1.5 M or 2.0 M), culture condition (1 day or 2 day), and taurine treatment. RESULTS: Percentage of recovery of cryopreserved islet was 56.8+/-10% after thawing. Viability was decreased from 97.2+/-1.1% before cryopreservation to 82.7+/-9.9% after thawing. Glucose stimulation index was reduced from 1.7+/-0.2 before cryopreservation to 1.2+/-0.8 after thawing. Nucleation method by metal rod showed better viability than control (no nucleation) or chamber nucleation method. Mean viability and glucose stimulation index was 81% and 1.5 in one day culture, and 84.2% and 1.2 in 2 day culture before cryopreservtion. Islet treated with taurine showed better insulin release and intracellular insulin content compared with non treated islets before and after cryopreservation. When 4000 IEQ (Islet Equivalent) of islets treated with taurine and non treated cryopreserved islets were transplanted into syngenic streptozotocin induced diabetic rat, all showed normoglycemia over 60 days. CONCLUSION: Cryopreservation of islets could give a tool of storage with preservation of islet secretion function. However pertinent effort to improve the recovery is needed in order to be used in the clinical islet transplantation.