Influence of the purification of human adult pancreatic islets on insulin secretion

Abstract

Background/Aim. The most effective method for human adult pancreatic islets purification is density-gradient centrifugation. The aim of this study was to analyze the effects of non-automated purification on preservation of functional capacity of human adult pancreatic islet cells. Methods. Human pancreata were obtained after pancreatectomy in the patients with chronic pancreatitis or benign tumors. Pancreatic islets were purified by non-automated method in discontinuous Ficoll density gradient. The samples were divided in 2 fractions: purified (P) and non-purified (NP) cultures. Islets were stained with diphenyl-thiocarbazone. The efficiency of separation was determined by comparing percentage of stained cells in P and NP cultures on day 1, 3 and 7 of shortterm cultivation. Glucose-stimulated insulin secretion was expressed as stimulation index (SI). Results. The results obtained showed a statistically significant difference (p < 0.01) between P and NP cultures. P cultures had higher percentages of stained cells (70.43 ± 3.97%, 73.77 ± 4.22% and 71.34 ± 4.69% on the first, third and seventh day of cultivation, respectively) than NP cultures (53.68 ± 1.71%, 57.14 ± 3.94% and 43.97 ± 4.56%, respectively). P cultures had higher values of SI for the first, third and seventh day of cultivation than NP cultures (0.45 ± 0.08, 0.80 ± 0.21, 1.28 ± 0.15 and 0.46 ± 0.10, 0.752 ± .0.16, 0.76 ± 0.11 for P and NP cultures respectively). The difference was statistically significant on day seven (p = 0.01). Conclusion. Although during purification process islets were exposed to a number of insults that might result in cellular damage and functional impairment, our assessments showed that islets in P cultures preserved their functional capacity better than islets in NP cultures, since they had greater insulin secretion.