Early ultra- and microstructural alterations in rat pancreas in alloxan-induced diabetes mellitus

An adequate experimental model is important to understand pathophysiological processes ongoing in the pancreas with diabetes mellitus. Our study was aimed to describe early ultra- and microstructural changes in the rat pancreas in 12-48 h after alloxan administration in a dose of 180 mg/kg. A histopathological examination of the endocrine pancreas revealed the loss of borders between endocrine cells, granular dystrophy and degranulation, sings of necrosis in central cells of the Langerhans islets and apoptosis of their peripheral ones manifested as DNA fragmentation and an increased expression of apoptosis markers. There was a gradual increase of a Langerhans islet area, a decreased percentage of insulin+ cells and an increased one of glucagon+ cells, as well as the presence of proliferating islet cells were found. Structural changes of the exocrine pancreas included fatty degeneration, signs of exocrine cell mitochondrial damage, increased acini, which are located mainly around the Langerhans islets, as well as perivascular edema and leukocytic infiltration. Described ultra- and microstructural alterations suggest a significant contribution of apoptosis to death of endocrine cells exposed to alloxan. Coexisting damage of the exocrine pancreas with its stroma involvement is for the first time described.

Analysis of the efficiency of gene-cell therapy in transgenic mice with amyotrophic lateral sclerosis phenotype

Amyotrophic lateral sclerosis is a neurodegenerative disease characterized by progressive death of cerebral and spinal motorneurons. Using behavioral tests we studied the efficiency of gene-cell therapy in SOD1 G93A transgenic mice receiving xenotransplantation of human umbilical cord blood mononuclear cells genetically modified with adenoviral vectors encoding vascular endothelial growth factor (VEGF) and reporter green fluorescent protein (EGFP) genes. The cells were transplanted to mice on week 27 of life (preclinical stage of the disease). Behavioral tests (open field, grip strength test) showed that transplantation of umbilical cord blood mononuclear cells expressing VEGF significantly improved the parameters of motor and explorative activity, grip strength, and animal survival. Thus, gene-cell therapy based on genetically modified mononuclear cells expressing VEGF can be efficient for the treatment of amyotrophic lateral sclerosis.

[C-kit is a marker of human pancreatic endocrinocyte stem cells]

The aim of our study was to analyze the expression of one of the markers of progenitor cell of different cell types - CD 117 (C-kit) - in human pancreas during prenatal development. The pancreas of human embryos and fetuses at 4-28 weeks of gestation as well as of infants aged up to 2nd postnatal month, was studied. In histological sections, the immunocytochemical reactions were performed with the antibodies against C-kit, insulin and glucagon. In situ hybridization was used for detection of proinsulin mRNA. First cells expressing C-kit were found in human pancreas at 8.5 weeks of gestation among ductal epithelial cells. At 11.5 weeks of gestation these cells were found to segregate from the ductal epithelium and start to form islets. From 8.5 weeks of gestation C-kit positive cells started to express glucagon and proinsulin mRNA, and after 11.5 weeks they also expressed insulin. Islet C-kit positive cells coexpressing both glucagon and insulin, were also found after the birth. It may be concluded that C-kit positive endocrinocyte progenitor cells are common for pancreatic islet A- and B-cells and they are preserved in he islets after the birth.