W Li1, M Yanoff, X Liu, X Ye. 1. Department of Ophthalmology, Peking Union Medical College Hospital, Beijing, China.
Abstract
OBJECTIVE: To investigate the nature of retinal capillary pericyte dropout in early human diabetic retinopathy. METHODS: In the present study, neural retinas of 12 postmortem eyes from 6 patients (3 diabetic and 3 nondiabetic) were first fixed in buffered formaldehyde and then digested with trypsin. The preparations of trypsin-digested retinal blood vessels were stained with terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) technique and then with perdiodic acid-Schiff technique (PAS), and counter-stained with hematoxylin to evaluate DNA fragmentation of cell nuclei and diabetic changes of retinal capillaries. RESULTS: TUNEL-positive apoptotic pericytes were observed in retinal capillaries in all three diabetic patients in this study. The TUNEL-positive pericytes were presented as darker stained cells with PAS-hematoxylin staining. A few TUNEL-positive retinal capillary endothelial cells were discovered in both eyes of one of the three diabetic patients. Neither TUNEL-positive pericytes nor positive endothelial cells were found in the three nondiabetic patients. A variety of typical diabetic microvascular changes were noticeable with PAS-hematoxylin staining in trypsin-digested retinal preparations from diabetic patients. These changes included thickened capillary walls, microaneurysms, "ghost-cell"-appearance of pericytes, acellular segments of capillaries, and a decreased ratio of retinal capillary pericytes to endothelial cells. All of these changes are characteristics of diabetic retinal microangiopathy. CONCLUSIONS: Retinal capillary pericyte apoptosis is a specific form of cell death which occurs during the early development of diabetic retinopathy. The significant decrease in the ratio of pericytes to endothelial cells and the predominant TUNEL-positive pericytes over endothelial cells suggest that a greater impact of apoptosis-related mechanisms occurs in pericytes than in endothelial cells and, thereby, a greater loss of pericytes takes place in early diabetic retinopathy. Apoptosis, therefore, is an important mechanism of pericyte dropout in the early diabetic retinopathy.
OBJECTIVE: To investigate the nature of retinal capillary pericyte dropout in early humandiabetic retinopathy. METHODS: In the present study, neural retinas of 12 postmortem eyes from 6 patients (3 diabetic and 3 nondiabetic) were first fixed in buffered formaldehyde and then digested with trypsin. The preparations of trypsin-digested retinal blood vessels were stained with terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) technique and then with perdiodic acid-Schiff technique (PAS), and counter-stained with hematoxylin to evaluate DNA fragmentation of cell nuclei and diabetic changes of retinal capillaries. RESULTS: TUNEL-positive apoptotic pericytes were observed in retinal capillaries in all three diabeticpatients in this study. The TUNEL-positive pericytes were presented as darker stained cells with PAS-hematoxylin staining. A few TUNEL-positive retinal capillary endothelial cells were discovered in both eyes of one of the three diabeticpatients. Neither TUNEL-positive pericytes nor positive endothelial cells were found in the three nondiabeticpatients. A variety of typical diabetic microvascular changes were noticeable with PAS-hematoxylin staining in trypsin-digested retinal preparations from diabeticpatients. These changes included thickened capillary walls, microaneurysms, "ghost-cell"-appearance of pericytes, acellular segments of capillaries, and a decreased ratio of retinal capillary pericytes to endothelial cells. All of these changes are characteristics of diabetic retinal microangiopathy. CONCLUSIONS: Retinal capillary pericyte apoptosis is a specific form of cell death which occurs during the early development of diabetic retinopathy. The significant decrease in the ratio of pericytes to endothelial cells and the predominant TUNEL-positive pericytes over endothelial cells suggest that a greater impact of apoptosis-related mechanisms occurs in pericytes than in endothelial cells and, thereby, a greater loss of pericytes takes place in early diabetic retinopathy. Apoptosis, therefore, is an important mechanism of pericyte dropout in the early diabetic retinopathy.
Authors: Ke Yuan; Elya A Shamskhou; Mark E Orcholski; Abinaya Nathan; Sushma Reddy; Hiroaki Honda; Vigneshwaran Mani; Yitian Zeng; Mehmet O Ozen; Lingli Wang; Utkan Demirci; Wen Tian; Mark R Nicolls; Vinicio A de Jesus Perez Journal: Circulation Date: 2019-04-02 Impact factor: 29.690