Diabetes & Metabolism Journal

Original Articles

Distension and Collagenase Digestion Time of The Pancreas are Critical Factors in Islet Isolation of Canine Pancreas.: Tae Young Yang, In Kyung Jeong, Seung Hoon Oh, Sang Hoon Lee, Dong Jun Kim, Jong Ryul Hahm, Jung Hwan Park, Jong Sung Kim, Jin Soo Han, Sung Joo Kim, Jae Hoon Chung, Yong Ki Min, Myung Shik Lee, Moon Kyu Lee, Kwang Won Kim; Korean Diabetes J. 2000;24(2):180-190. Published online January 1, 2001

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Abstract PDF: BACKGROUND
S: One of the main problems conditioning the outcome of islet transplantation is the ability to separate a sufficient number of viable islets with preserved function. Islet purification is critically affected by all of the isolation stages, Thus, it is necessary to set up the standard isolation method that islets are separate well from acinar without compromising islet yield and viability. METHODS: Twenty three adult mongrel dogs were used for the experiment of total pancreatectomy with islet isolation. The islets were properly isolated by a modified Recordi method. The obtained islets were further purified by centrifugation on discontinuous gradients using cell separation system (Model 2991, Cobe, Lakewood Colo). We evaluatad islet number (islet equivalent number, 150 gm equivalents/kg of recipient body weight, lEq/kg), purity. cell volume, viabilty, recovery rate, and comparison of outcome according to the isolation conditions. RESULTS: 1) The mean of islet numbers before purification were 13543+/-943 lEq/kg, digestion times were 13.8+/-2.6 min. digestion tamperature was b was 59,7+/-7.0%, viability was 90.0+/-2.1%, cell volume was 4.7+/-1.1 mL, islet number after purification were 4064+/-361 lEq/kg, and recovery rate was 29+2.9. 2) Isolated islet numbers were different according to the degree of pancreas distension with collagenase, digestion temperature, and digestion time. 3) The best conditions for islet isolation were above 37.5 degree C in temperature at recirculation of collagenase, within 12min in digestion time and well distended pancreas with collagenase. 4) According to multiple regression adjusted by variable factors, the degree of pancreas distension with collagenase and digestion time were independently associated factors for successful islet isolation. CONCLUSIONS: In this study, we concluded that the degree of pancreas distension with collagenase and digestion time were independent factors for successful islet isolation and the best conditions for islet isolation were above 37.5 degree C in temperature at recirculation of collagenase, within 12 min in digestion time and well distended pancreas with collagenase.

Critical Factors Determined Islet Graft Function In Canine Islet Autotransplantation.: Tae Young Yang, In Kyung Jeong, Seung Hoon Oh, Sang Hoon Lee, Dong Jun Kim, Jong Ryul Hahm, Byung Joon Kim, Kyu Jeung Ahn, Sung Joo Kim, Jae Hoon Chung, Yong Ki Min, Myung Shik Lee, Moon Kyu Lee, Kwang Won Kim; Korean Diabetes J. 2000;24(2):170-179. Published online January 1, 2001

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Abstract PDF: BACKGROUND
Islet cell transplantation is an attractive alternative to whole organ pancreas transplantation, since it is clearly safer and simpler surgical procedure for the reciplents. However, several obstacles still remain, because the free islets appear to be more susceptible to non-specific inflammatory damage or immune mediated destruction than islets in an intact pancreas. Therefore, the purpose of this study is to examine the functional outcome of islet autograft and the factors related to the islets graft survival in mongrel dogs. METHODS: Twelve adult mongrel dogs weighting 12~16 kg were used for the experiment of total pancratectomy and islet autotransplantation. The islets were properly isolated by a modified Recordi method. The obtained islets were further purified by centrifugation on discontinuous gradients using cell separation system (Model 2991, Cobe, Lakewood Colo). After the heparization(50U/kg), the islets were injected slowly into the liver through the portal vain for 30 minutes. The post-transplantation intravenous glucose tolerence test (IVGTT) with glucose disappearance rate (K), liver function test (LFT), fasting plasma glucose (FPG) ware measured periodically. RESULTS: I) The median of Ks were 1.3%/min (range 0.3~2.1) and the lEq/kg (150 m equivalents/kg of recipient body weight) was 3520 (range 1350-6550). The Ks in recipients with high lEq/kg (> or =5,000) were significantly higher than those in recipients with low lEq/kg (<5,000)(r=0.78, p<0.05). 2) The islet cell viability were estimated to be 95% and the median of the required insulin dosage for the maintenance of normal FPG were 0.7 (range 0~1.6) U/kg/day, The insulin requirement correlated well with the level of lEq/kg (r=-0.90, p<0.01). 3) The median of the volume of the transplanted pancreatic islet cell were 2.1 mL (range 0.7~5.0) and the purity was 60k (range 10~95), The portal pressure gradients of during the transplant procedure were 4.0(range 0.5~12.0) cmH20. The portal pressure gradients in recipients with high purity were significantly lower than those in recipients with low purity (r=-0,80, p<0,05). CONCLUSIONS: In this study, we confirmed that autotransplantation of islet cell on the pancreatectomized dogs can render nearly normoglycemia, and transplanted islet mass was most critical factor to successful autotransplantation in canine model.

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