Aim: To investigate the acute and chronic effects of nateglinide versus acarbose on plasma asymmetric dimethylarginine (ADMA) levels and lipid profiles in patients with newly diagnosed type 2 diabetes. Methods: A crossover trial of nateglinide and acarbose was conducted on 16 drug-naïve patients with newly diagnosed type 2 diabetes during a total period of 9 weeks. Plasma glucose, serum insulin, free fatty acids (FFA), lipids and lipoproteins, and plasma ADMA were measured. Results: The efficiencies of a single dose of nateglinide (120 mg) and acarbose (50 mg) for lowering postprandial hyperglycemia were similar. Compared to acarbose, nateglinide significantly increased postprandial insulin release after a standard meal test in patients with type 2 diabetes. Nateglinide acutely decreased postprandial 120-min FFA concentrations and 240-min ADMA levels more significantly than acarbose. The fasting high-density lipoprotein cholesterol (HDL-C) level increased and the low-density lipoprotein cholesterol (LDL-C) level decreased significantly, but the fasting levels of triglycerides, total cholesterol, and ADMA were unchanged after 4 weeks of treatment with nateglinide. Acarbose did not affect fasting lipid profiles or the ADMA levels after 4 weeks of treatment. Conclusion: These results suggest that the reduction of postprandial FFA and ADMA concentrations induced by nateglinide may be associated with the partial restoration of early phase insulin secretion and may impart a cardiovascular advantage in comparison with acarbose.

The side population (SP) phenotype might represent a common molecular feature for a wide variety of stem cells. The aim of this study was to investigate whether monoclonal SP progenitor cells were established from human fetal pancreas. Islet-like cell clusters (ICCs) were isolated from human fetal pancreas. Monolayer epithelium-like cells were obtained from the ICCs and passaged thereafter. Single SP or non-SP cell were sorted from these cells at the sixth passage. The rate of clone formation was about 2.7% for the SP cells, whereas there was no clone formation for the non-SP cells. The SP cell clones were further expanded for more than 15 passages and induced for differentiation into cells with characteristics of pancreatic -cells. We show for the first time that the monoclonal SP progenitors are established from human fetal pancreas. Therefore, this study may offer a novel method to purify pancreatic progenitor cells from human tissues.

新生Wistar大鼠离体胰岛与细胞因子孵育后，观测胰岛素释放和一氧化氮（NO）生成的变化，并用逆转录2聚合酶链反应（RT-PCR）观察IL-18受体信号链（IL-18Rβ）mRNA的表达水平。结果表明：（1）0.625～10nmol/L基因重组小鼠（rm）IL-18孵育胰岛24h后，对累积的和葡萄糖刺激的胰岛素释放以及NO生成均无显著效应；（2）200U/ml基因重组大鼠（rr）γ干扰素（IFN-γ）或250U/ml基因重组人（rh）肿瘤坏死因子-α（TNF-α）单独存在对胰岛素释放和NO生成均无明显效应，也不能促使10nmol/LrmIL-18对胰岛素释放和NO生成产生影响；（3）200U/mlrrIFN-γ+250U/mlrhTNF-α或15pg/mlrhIL-1β均明显促进NO生成和抑制胰岛素释放，而10nmol/LrmIL-18则不影响IFN-γ+TNF-α或IL-1β的上述效应；（4）即使经IL-1β和（或）IFN-γ+TNF-α或IL-12孵育后，大鼠胰岛素瘤（RIN）细胞或离体大鼠胰岛仍未见IL-18RβmRNA的表达。提示IL-18在细胞因子所致胰岛β细胞损伤中不发挥直接作用，原因是IL-18受体在胰岛β细胞中不表达。