速效胰岛素类似物对体外人胰腺胰岛中胰岛素信号的直接作用。

Department of Endocrinology and Metabolism, Ospedale Cisanello, via Paradisa 2, University of Pisa, 56121 Pisa, Italy.

Diabetes Metab. 2011 Sep;37(4):324-9. doi: 10.1016/j.diabet.2010.12.002. Epub 2011 Feb 26.

AIMS

Studies suggest that insulin-signaling molecules are present in the pancreatic islets. For this reason, the effects of insulin glulisine, insulin aspart and regular human insulin (RHI) on the function and molecular features of isolated human pancreatic islets were investigated.

METHODS

Human pancreatic islets were prepared by collagenase digestion and density-gradient purification of pancreata from multiple organ donors. Islets were then cultured for 48 h in the presence of 5.5 (normal) or 22.2 (high) mmol/L of glucose with and without glulisine, aspart and RHI (10 or 100 nmol/L). Functional (glucose-stimulated insulin secretion) and molecular (quantitative RT-PCR and immunoblot) studies were performed at the end of the different incubation conditions.

RESULTS

Glucose-stimulated insulin secretion was blunted in islets cultured in 22.2 mmol/L of glucose, with no significant effects from the exogenous added insulins. In islets maintained at 5.5 mmol/L of glucose, insulin receptor (IR) expression was reduced by low RHI, while phosphatidylinositol-3 kinase p110-alpha (PI3K) was enhanced by both concentrations of glulisine and aspart, and by high RHI. In islets preexposed to high glucose, IR expression was increased by both concentrations of aspart and RHI, but not by glulisine. Glulisine at high concentration significantly (P<0.05) increased PI3K expression. Glulisine and RHI significantly increased IRS-2 phosphorylation compared with control and aspart (P<0.05).

CONCLUSION

Insulin analogues have differential effects on the expression of insulin-signaling molecules in human pancreatic islets that are also dependent on the degree of glucose exposure.

目的

研究表明胰岛素信号分子存在于胰岛中。基于此，本研究旨在探究赖脯胰岛素、门冬胰岛素和人胰岛素（RHI）对分离的人胰岛功能和分子特征的影响。

方法

采用胶原酶消化和胰岛密度梯度纯化的方法从多位器官捐献者的胰腺中分离胰岛。然后，胰岛在 5.5mmol/L（正常）或 22.2mmol/L（高）葡萄糖存在下培养 48 小时，并加入赖脯胰岛素、门冬胰岛素和 RHI（10 或 100nmol/L）。在不同的孵育条件结束时进行功能（葡萄糖刺激胰岛素分泌）和分子（定量 RT-PCR 和免疫印迹）研究。

结果

在 22.2mmol/L 葡萄糖中培养的胰岛，葡萄糖刺激的胰岛素分泌受到抑制，而外源性添加的胰岛素没有显著影响。在 5.5mmol/L 葡萄糖培养的胰岛中，低浓度的 RHI 降低了胰岛素受体（IR）的表达，而赖脯胰岛素和门冬胰岛素的两种浓度以及高浓度的 RHI 均增强了磷脂酰肌醇-3 激酶 p110-α（PI3K）的表达。在高葡萄糖预暴露的胰岛中，两种浓度的门冬胰岛素和 RHI 均增加了 IR 的表达，但赖脯胰岛素没有。高浓度的赖脯胰岛素显著（P<0.05）增加了 PI3K 的表达。与对照组和门冬胰岛素相比，赖脯胰岛素和 RHI 显著增加了 IRS-2 的磷酸化（P<0.05）。