AIM: To isolate nestin-positive progenitor cells from human fetal pancreas and to detect their surface markers and their capability of proliferation and differentiation into pancreatic islet endocrine cells in vitro. METHODS: Islet-like cell clusters (ICCs) were isolated from human fetal pancreas by using collagenase digestion. The free-floating ICCs were handpicked out and cultured in a new dish. After the ICCs developed into monolayer epithelium-like cells, they were passaged and induced for differentiation. Reverse transcription polymerase chain reaction (RT-PCR), immunofluorescence stain, fluorescence-activated cell sorting (FACS) and radioimmunoassay (RIA) were used to detect the expression of cell markers. RESULTS: (1) The monolayer epithelium-like cells had highly proliferative potential and could be passaged more than 16 times in vitro. (2) RT-PCR analysis and immunofluorescence stain showed that these cells expressed both nestin and ABCG2, two of stem cell markers. (3) FACS analysis revealed that CD44, CD90 and CD147 were positive, whereas CD34, CD38, CD45, CD71, CD117, CD133 and HLA-DR were negative on the nestin-positive cells. (4) RT-PCR analysis showed that the mRNA expression of insulin, glucagon and pancreatic-duodenal homeobox gene-1 (PDX-1) was detected，whereas the expression of nestin and neurogenin 3 (Ngn3) was disappeared in these cells treated with serum-free media supplemented with the cocktail of growth factors. Furthermore, the intra-cellular insulin content was detected by RIA after the induction culture. CONCLUSION: Nestin-positive cells isolated from human fetal pancreas possess the characteristics of pancreatic progenitor cells since they have highly proliferative potential and the capability of differentiation into insulin-producing cells in vitro. Interestingly, the nestin-positive pancreatic progenitor cells share many phenotypic markers with mesenchymal stem cells derived from bone marrow.

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。

目的 探讨人胚胎胰腺中干细胞特异性标志巢蛋白（Nestin）的表达及阳性细胞的分布。方法 用连续切片免疫组织化学染色方法检测16周胎龄人胚胎胰腺中巢蛋白、胰岛素、胰升糖素和导管上皮标志细胞角蛋白19（CK19）的表达及分布。结果 16周人胚胎胰腺中可检测到巢蛋白阳性细胞，分布于胰岛以及胰导管和腺泡结构中，并且以腺泡结构和小导管中的数目为多。部分胰岛素和CK19染色强阳性的细胞中巢蛋白染色为弱阳性，胰升糖素强阳性的部位则未见巢蛋白染色阳性的细胞。结论 人胚胎胰腺中存在巢蛋白表达的细胞；巢蛋白阳性细胞可能是胰腺组织中一个特殊的细胞亚群，代表了一群未成熟细胞。