George Biju, Chen Shali, Chaudhary Varun, Gonder John, Chakrabarti Subrata
Department of Pathology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada.
Curr Eye Res. 2009 Feb;34(2):134-44. doi: 10.1080/02713680802585946.
Non-vascular epiretinal membranes (ERM) and neovascular membrane in proliferative diabetic retinopathy (PDR) are recognized causes of visual impairment. Both ERMs and neovascular membranes in PDR consist of cellular components and extracellular matrix (ECM) proteins such as fibronectin (FN) and collagen. Transforming growth factor-beta (TGF-beta) and endothelin-1 (ET-1) regulate ECM protein production. In this study, we investigated ECM proteins and their regulators in ERMs and vitreous from PDR subjects and non-diabetic subjects undergoing vitrectomy.
ERMs from non-diabetic subjects undergoing membrane peeling were collected. Vitreous samples from non-diabetic and PDR subjects undergoing vitrectomy were also collected and separated into solid pellets consisting of fibrovascular tissue and vitreous fluid. Real-time PCR was done for estimating mRNA levels of extracellular matrix proteins like collagen, FN, its splice variant extra-domain B containing FN (EDBFN), and their regulators, TGF-beta and ET-1. ELISA was done to detect the EDBFN level in blood and vitreous from non-diabetic and PDR subjects undergoing vitrectomy.
ECM proteins, including FN, its splice variant EDBFN, and collagen were significantly upregulated in the ERMs and PDR compared to vitreous from both other two group. The levels were, however, higher in the ERM. ECM protein regulators like TGF-beta and ET-1 were also elevated. FN and EDBFN show significant correlation with TGF-beta in vitreous but not in ERMs. Plasma and vitreous EDBFN were elevated in the PDR subjects compared to non-diabetic subjects.
Data from these studies show that ECM proteins such as EDBFN and collagen are upregulated in ERM and PDR, and are regulated by TGF-beta. Elevated serum EDBFN in the PDR may potentially be further explored as a possible molecular marker for the early detection of diabetic end organ damages.
非血管性视网膜前膜（ERM）和增殖性糖尿病视网膜病变（PDR）中的新生血管膜是导致视力损害的公认原因。PDR中的ERM和新生血管膜均由细胞成分和细胞外基质（ECM）蛋白组成，如纤连蛋白（FN）和胶原蛋白。转化生长因子-β（TGF-β）和内皮素-1（ET-1）调节ECM蛋白的产生。在本研究中，我们调查了PDR患者和接受玻璃体切除术的非糖尿病患者的ERM和玻璃体中的ECM蛋白及其调节因子。
收集接受膜剥除术的非糖尿病患者的ERM。还收集了接受玻璃体切除术的非糖尿病患者和PDR患者的玻璃体样本，并分离成由纤维血管组织和玻璃体液组成的固体沉淀物。进行实时PCR以估计细胞外基质蛋白如胶原蛋白、FN、其含额外结构域B的剪接变体FN（EDBFN）及其调节因子TGF-β和ET-1的mRNA水平。进行ELISA检测接受玻璃体切除术的非糖尿病患者和PDR患者血液和玻璃体中的EDBFN水平。
与其他两组的玻璃体相比，ERM和PDR中的ECM蛋白，包括FN、其剪接变体EDBFN和胶原蛋白显著上调。然而，ERM中的水平更高。TGF-β和ET-1等ECM蛋白调节因子也升高。FN和EDBFN在玻璃体中与TGF-β呈显著相关，但在ERM中无相关性。与非糖尿病患者相比，PDR患者的血浆和玻璃体EDBFN升高。
这些研究的数据表明，EDBFN和胶原蛋白等ECM蛋白在ERM和PDR中上调，并受TGF-β调节。PDR中血清EDBFN升高可能作为糖尿病终末器官损伤早期检测的一种可能的分子标志物进一步探索。
