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.

Analysis on Recurrence of an Invasive Ductal Adenocarcinoma of the Pancreas

PURPOSE: Most patients who undergo a curative resection of a pancreatic ductal adenocarcinoma (PDAC) develop recurrence, usually at the tumor bed or in the liver, which has been associated with the poor prognosis of a PDAC. In this study, the clinical characteristics of the recurrences following curative resection of a PDAC were analyzed to discover the surgical and adjuvant treatment strategies. METHODS: Between May 1990 and December 2002, 156 patients diagnosed with a recurrence after curative resection of a PDAC were analyzed for the pattern of recurrence, time of recurrence, associations with stage and adjuvant therapy, and survival using a retrospective review of their medical records. RESULTS: Local and systemic recurrences were found in 41.0 and 25.7%, respectively. About half of the recurrences occurred within 6 months of the operation. A local recurrence was found more frequently in the body and tail than in the head, which occurred earlier than a systemic recurrence at an advanced stage. A local recurrence occurred in 40% of patients treated with surgery alone, and in 29.4% of those treated with surgery plus radiotherapy, whereas a systemic recurrence occurred in 25.5% of patients treated with surgery alone, and in 17.4% of those treated with surgery plus chemotherapy. The patients with a local recurrence had a significantly prolonged median disease free survival time (7.8 months) than those with a systemic recurrence (5.8 months). The two-year survival rate for the locally recurred patients was greater than that for those with a systemic recurrence (23.4% vs. 17.5%). CONCLUSION: Our study showed a high rate and early occurrence of local recurrence, with a poor survival rate within 1 year, even after curative resection of the PDAC. There is still a great need for advances in meticulous surgical techniques for the control of local recurrence, especially in body and tail lesion or an advanced stage, and new adjuvant therapeutic modalities following curative resection to improve the survival rate of patients with a PDAC.

Comparative Study on Biologic and Immunologic Characteristics of the Pancreas Islet Cell between 24degrees C and 37degrees C Culture in the Rat / 대한이식학회지

PURPOSE: Islet cell transplantation, as an alternative approach to endocrine cell replacement to treat the diabetes mellitus, has received significant attention because it holds several advantages over whole gland transplantation. However cell damage from islet isolation and immunologic rejection after transplantation prevent from successful clinical application for diabetic patients. Culture of cells at low temperature has known to stabilize the cell viability, and to decrease the immunologic antigenicity. Aim of this study is to investigate the effect of culture at 24oC on cell viability, cellular function, immunogenicity and cytokine profiles in rat pancreas islet. METHODS: Pancreas islets were isolated from Lewis rat and cultured at 24oC or 37oC during 14 days. Islet recovery after culture period was counted as islet equivalent number, and islet viability was examined with fluorescent vital staining (FDA/PI). Islet function was measured with glucose stimulation test. Annexin V expression and MHC class I and II expression were measured with flow cytometric assay for apoptosis and immunogenicity respectively. Lymphocyte cell proliferation through mixed lymphocyte islet culture was examined with WST-1 proliferation assay. Cytokine profiles were analyzed with quantitative real time RT-PCR. All these parameters were measured on 1, 3, 5, 7, 14 culture days after islet isolation. RESULTS: Islet recovery was higher in islet cultured at 24oC than in islet cultured at 37oC without change of viability. Insulin secretion after glucose stimulation was more effective in 24oC culture condition. Decrease of apoptotic cell death was demonstrated in 24oC cultured islet. MHC class I and II expression on islets and lymphocyte proliferation when cocultured with islets were less prominent in 24oC cultured islet. TNF-alpha and IL-4 cytokine expression was higher in islet cultured at 24oC than in islet cultured at 37oC. IL-1beta and IL-10 cytokine expression were similar in both culture condition. CONCLUSION: This study demonstrated that cell recovery and function are increased in islet cultured at 24oC than in islet cultured at 37oC while antigenicity and proinflammatory cytokine expression are decreased. Low temperature culture can be a good approach to prevent the loss of islet mass, and to reduce the immunologic rejection of transplanted islet for successful clinical islet transplantation.