Neoplastic transformation of propagable cultured rat pancreatic duct epithelial cells by azaserine and streptozotocin

Evolutionary interactions between diabetes and development

Because of the complications of diabetes affecting the mothers and their fetus/newborns are less known, this review examined the epidemiologic and mechanistic issues involved in the developmental programming of diabetic mothers. This overview showed that sperm, egg, zygote or blastocyst derived from diabetic parents may develop into offspring with high risk of any type of diabetes, even if placed in a normal uterus, producing developmental delay, embryopathy, geno- and cyto-toxicity, teratogenic changes, free radicals and apoptosis. These early insults may then lead to an increased rate of miscarriage and congenital anomalies depending on free radicals signaling and cell-death pathways involved by the diabetogenic agents. Furthermore, sperm, egg, zygote or blastocyst from normal parents will have an increased risk of diabetes if placed in a diabetic uterus. Interestingly, diabetes has deleterious effect on male/female reproductive functions and on the development of the blastocysts/embryos. Indeed, this review hypothesized that the long-term effects of diabetes during the pregnancy (gestational diabetes) may influence, generally, on the health of the embryos, newborns (perinatal life) and adulthood. However, there are obvious species differences between pregnant women and animal models. Thus, maintaining normoglycaemia during pregnancy may play an important role in a healthy life for the newborns.

Genotoxicity of streptozotocin

Streptozotocin (Streptozocin, STZ, CAS No. 18883-66-4) is a monofunctional nitrosourea derivative isolated from Streptomyces achromogenes. It has broad spectrum antibiotic activity and antineoplastic properties and is often used to induce diabetes mellitus in experimental animals through its toxic effects on pancreatic beta cells. STZ is a potent alkylating agent known to directly methylate DNA and is highly genotoxic, producing DNA strand breaks, alkali-labile sites, unscheduled DNA synthesis, DNA adducts, chromosomal aberrations, micronuclei, sister chromatid exchanges, and cell death. This antibiotic was found to be mutagenic in bacterial assays and eukaryotic cells. STZ is also carcinogenic; a single administration induces tumors in rat kidney, liver, and pancreas. Several lines of evidence indicate that free radicals are involved in the production of DNA and chromosome damage by this compound. Because of the use of STZ as an antineoplastic agent, the study of its genotoxicity has considerable practical significance. The purpose of this review is to present our current knowledge regarding the genotoxicity of STZ.

Culture of human main pancreatic duct epithelial cells

Attempts to grow human pancreatic duct epithelial cells in long-term culture have proven difficult. We have developed a system of growing these cells for several passages by adapting methods used to culture dog pancreatic duct cells. Epithelial cells were enzymatically dissociated from the main pancreatic duct and plated onto collagen-coated culture inserts suspended above a human fibroblast feeder layer. After primary culture, the cells were either passaged onto new inserts or plastic tissue culture plates in the absence of collagen. Cells grown on the latter plates were maintained in a serum-free medium. Primary pancreatic duct epithelial cells grow steadily to confluence as a monolayer in the feeder layer system. After primary culture, cells passaged onto new inserts with fresh feeder layer or plastic plates and fed with serum-free medium continued to develop into confluent monolayers for up to four passages. The cells were columnar with prominent apical microvilli, sub-apical secretory vesicles, and lateral intercellular junctions resembling the morphology of normal in vivo epithelial cells. These cells were also positive for cytokeratin 19, 7, and 8 and carbonic anhydrase II, as measured by immunohistochemistry. Metabolically, these cells synthesized and secreted mucin, as measured by incorporation of tritiated N-acetyl-D-glucosamine. In conclusion, we demonstrated that human pancreatic epithelial cells from the main duct can be successfully grown in culture and repeatedly passaged using a feeder layer system, with serum-free medium, and in organotypic cultures.

Morphology of the pancreatic duct system in mammals

The morphology of pancreatic excretory duct segments was reviewed in mammals. The fine structure of the epithelial lining was described in intercalated ducts, intra- and extralobular ducts, and in major pancreatic ducts. Morphological characteristics of the various cell types comprising to the duct epithelium were detailed. Principal cells in the epithelial linings of interlobular and major pancreatic ducts ("Wirsungiocytes") were discussed with respect to their appearance as either clear or dark variety. In addition, the capacity of both these cell types in elaborating mucoid glycoprotein, secretions was considered and intra- and extraepithelial mucoid glands of major pancreatic ducts (ductular glands, accessory glands) was described. Finally, the wall composition of the various excretory duct segments was described. The presence of smooth muscle cells, myofibroblasts, and a peculiar periductal vascular plexus in major interlobular ducts and in main pancreatic ducts was emphasized.