Beltramo E, Buttiglieri S, Pomero F, Allione A, D'Alù F, Ponte E, Porta M
Department of Internal Medicine, University of Turin, C.so AM Dogliotti 14, 10126 Torino, Italy.
Diabetologia. 2003 Mar;46(3):409-15. doi: 10.1007/s00125-003-1043-6. Epub 2003 Feb 26.
AIMS/HYPOTHESIS: Thickening of the basement membrane and selective loss of pericytes occur early in diabetic retinopathy. As we showed previously that pericyte adhesion is impaired on extracellular matrix produced by endothelial cells in high hexose concentrations, we aimed to verify if altered adhesion could influence pericyte viability and replication.
Conditioned extracellular matrices were obtained by growing human umbilical vein endothelial cells in media containing 28 mmol/l D-glucose, with or without the inhibitors of protein glycation thiamine or aminoguanidine, and D-galactose or L-glucose up to 28 mmol/l. Having removed the endothelium, bovine retinal pericytes were grown on these matrices and, in separate experiments, on laminin, fibronectin or type IV collagen. Pericyte viability and replication were measured by cell counts and DNA synthesis after 7 days, cell cycle traversal after 2 days and apoptosis after 18 h, 2 days and 7 days.
Pericyte counts and DNA synthesis were reduced on matrices produced in high D-glucose and D-galactose, whilst matrix obtained in L-glucose reduced DNA synthesis but not counts. Both thiamine and aminoguanidine corrected reduced pericyte viability when added to high D-glucose. Cell cycle and apoptosis were not affected by growing pericytes on different conditioned matrices. Laminin, fibronectin and type IV collagen did not modify pericyte replication.
CONCLUSIONS/INTERPRETATIONS: Reduced pericyte counts could depend on impaired initial adhesion to the extracellular matrix produced by endothelium in high hexose concentrations, rather than impaired replication or viability. Altered cell-matrix interactions might facilitate pericyte dropout in diabetic retinopathy, independently of the effects of high glucose on pericyte replication.
目的/假设：糖尿病视网膜病变早期会出现基底膜增厚和周细胞选择性丢失。正如我们之前所表明的，在高糖浓度下内皮细胞产生的细胞外基质上，周细胞的黏附会受损，我们旨在验证黏附改变是否会影响周细胞的活力和增殖。
通过在含有28 mmol/l D - 葡萄糖的培养基中培养人脐静脉内皮细胞来获得条件性细胞外基质，培养基中添加或不添加蛋白质糖基化抑制剂硫胺素或氨基胍，以及高达28 mmol/l的D - 半乳糖或L - 葡萄糖。去除内皮后，将牛视网膜周细胞接种在这些基质上，在单独的实验中，也接种在层粘连蛋白、纤连蛋白或IV型胶原上。7天后通过细胞计数和DNA合成来测量周细胞的活力和增殖，2天后测量细胞周期进程，在18小时、2天和7天后测量细胞凋亡情况。
在高D - 葡萄糖和D - 半乳糖产生的基质上，周细胞计数和DNA合成减少，而在L - 葡萄糖中获得的基质减少了DNA合成但未减少细胞计数。当添加到高D - 葡萄糖中时，硫胺素和氨基胍都能纠正周细胞活力降低的情况。在不同的条件性基质上培养周细胞，细胞周期和凋亡不受影响。层粘连蛋白、纤连蛋白和IV型胶原均未改变周细胞的增殖。
结论/解读：周细胞计数减少可能取决于在高糖浓度下对内皮细胞产生的细胞外基质的初始黏附受损，而非增殖或活力受损。细胞 - 基质相互作用的改变可能促进糖尿病视网膜病变中周细胞的丢失，这与高糖对周细胞增殖的影响无关。
