Effects of Candida on insulin secretion of human adult pancreatic islets and possible onset of diabetes.

This study aims to determine the origin of Candida contamination of pancreatic tissue cultures, as well as its influence on insulin secretory activity of the pancreatic islets. Pancreatic tissue was obtained after pancreatectomy in patients who had chronic pancreatitis or benign tumours. Islets were isolated under aseptic conditions by a manual method. Microbiological analysis was performed by standard procedures and secretory activity was determined on the first, third and seventh day of cultivation. Insulin stimulation index (SI) on the first day of incubation was 0.665 +/- 0.082 and 0.982 +/- 0.167 for sterile and infected cultures, respectively (expressed as means +/- SE). On the third day of cultivation, the SI for sterile cultures was 0.645 +/- 0.071 while these value were higher in contaminated cultures (1.252 +/- 0.413). On the seventh day, SI was 0.853 +/- 0.032 and 1.239 +/- 0.169 for sterile and infected cultures, respectively (P = 0.05). Analysis of results for the first, third and seventh day of incubation and comparison of both groups showed that SI was 0.721 +/- 0.041 for sterile cultures, while for contaminated cultures it was higher by 37.68% (SI = 1.157 +/- 0.154; P = 0.01). The results show that cell culture contamination originates from an original pancreatic tissue infection, and that Candida can provoke an elevated level of insulin secretion in such patients, thus increasing chances for the onset of diabetes.

Effect of low temperature cultivation on insulin secretory of human pancreatic islets.

The experiment compared the physiological function (insulin secretory capacity) and membrane integrity of human adult pancreatic islets incubated in culture at 37°C and 24°C. Pancreatic tissue was digested with Collagenase XI, using a non-automated method. Cultures were incubated at 37°C and 24°C. Secretory capacity of the islets is determined by measuring of the stimulation index (SI) on the 1st, 3rd and 7th day of cultivation. Membrane integrity of the islets was determined by dithizone staining. Both groups of examined cultures show a slight increase in SI during the incubation. However islets incubated at 24°C show higher SI values than those incubated at 37°C on the 1st, 3rd and 7th day of incubation. And on the first day of incubation, this difference was statistically significant (p <0.05). Islets incubated at 37°C showed preservation of membrane integrity, the islets are regular spherical shape, while those incubated at 24°C lose such an organization. During the seven-day cultivation, islets incubated at a standard temperature of 37°C show less preserve physiological functions in relation to cultures incubated at 24°C, but islets incubated at 37°C show more regular morphological forms.

Effects of bacterial infection on insulin secretory capacity of human adult pancreatic islets.

This study aims to determine the origin of bacterial contamination of pancreatic tissue cultures, as well as its influence on insulin secretory activity (expressed as stimulation index [SI]) of the pancreatic islets. Pancreatic tissue was obtained after pancreatectomy in patients who had chronic pancreatitis or benign tumours. Islets were isolated under aseptic conditions by a manual method. Microbiological analyses were performed by standard procedures and the SI was determined on the first and seventh day of cultivation. In cultures contamminated by Pseudomonas, SI was 1.58 +/- 1.16 on day 1 and 0.22 +/- 0.14 on day 7 (P<0.01). Cultures contaminated by Enterobacter showed an SI of 0.21 +/- 0.1 on day 1, which increased to 1.19 +/- 0.66 on day 7 (P<0.01). In cases of Staphylococcus contamination, SI was 0.07 +/- 0.05 on day 1 and 0.33 +/- 0.21 on day 7 (P<0.01). The study shows that cell culture contamination originates from an original pancreatic tissue infection. The presence of bacteria may reduce or increase insulin secretion in cell culture, depending on the type of microorganism, and this can provoke reduced or elevated levels of insulin secretion in recipients, thus increasing the chances for the onset of diabetes.