Exploring the role of Müller cells-derived exosomes in diabetic retinopathy.

Exosomes are nanosized vesicles that have been reported as cargo-delivering vehicles between cells. Müller cells play a crucial role in the pathogenesis of diabetic retinopathy (DR). Activated Müller cells in the diabetic retina mediate disruption of barrier integrity and neovascularization. Endothelial cells constitute the inner blood-retinal barrier (BRB). Herein, we aim to evaluate the effect of Müller cell-derived exosomes on endothelial cell viability and barrier function under normal and hyperglycemic conditions. Müller cell-derived exosomes were isolated and characterized using Western blotting, nanoparticle tracking, and electron microscopy. The uptake of Müller cells-derived exosomes by the human retinal endothelial cells (HRECs) was monitored by labeling exosomes with PKH67. Endothelial cell vitality after treatment by exosomes under normo- and hypoglycemic conditions was checked by MTT assay and Western blot for apoptotic proteins. The barrier function of HRECs was evaluated by analysis of ZO-1 and transcellular electrical resistance (TER) using ECIS. Additionally, intracellular Ca+2 in HRECs was assessed by spectrofluorimetry. Analysis of the isolated exosomes showed a non-significant change in the number of exosomes isolated from both normal and hyperglycemic condition media, however, the average size of exosomes isolated from the hyperglycemic group showed a significant rise when compared to that of the normoglycemic group. Müller cells derived exosomes from hyperglycemic condition media markedly reduced HRECs cell count, increased caspase-3 and Annexin V, decreased ZO-1 levels and TER, and increased intracellular Ca+ when compared to other groups. However, treatment of HRECs under hyperglycemia with normo-glycemic Müller cells-derived exosomes significantly decreased cell death, preserved cellular integrity and barrier function, and reduced intracellular Ca+2. Collectively, Müller cell-derived exosomes play a remarkable role in the pathological changes associated with hyperglycemia-induced inner barrier dysfunction in DR. Further in vivo research will help in understanding the role of exosomes as therapeutic targets and/or delivery systems for DR.

TLR4, IgA and EpCAM Expression in Colorectal Cancer and Their Possible Association with Microbiota as a Pathogenic Factor; An Immunohistochemical and Genetic Study.

BACKGROUND: The pathogenesis of inflammatory bowel disease (IBD) and colorectal cancer (CRC) is thought to be related to immune response against gut microbiota. TLR4, IgA, and EpCAM have a role in intestinal local immune response and their altered expression related to both IBD and CRC. Lipopolysaccharide (LPS) is the main activator of TLR4. The objective of this study is to evaluate the possible role of intestinal microbiota in the pathogenesis of IBD and CRC through expression of TLR4, IgA and EpCAM. METHODS: One hundred five cases were divided into (Group 1/ Control: 10 sections of normal colonic mucosa, Group 2/CRC: 51 cases, Group 3/IBD: 44 cases). Immunohistochemistry for TLR4, IgA, and EpCAM was done. LPS was assessed in all groups. TLR4 gene and protein expression were assessed in colorectal cancer cell line by RT-PCR and immunocytochemistry. RESULTS: There was a significant correlation between TLR4 and tumor grade (P value 0.003 and 0.01 respectively). A significant correlation was found between IgA expression and T stage (P value 0.02) and between EpCAM expression and histologic type (P value 0.02). In comparison of CRC patients to controls; there was a statistically significant different expression of TLR4 positivity, IgA positivity and EpCAM (P value <0.001, 0.004, <0.001 respectively). Patients with CRC were compared to colitis patients and there was a statistically significant different expression of IgA positivity and EpCAM expression (P value <0.001). There was significant higher expression of TLR4 in CRC cell line than the fibroblast by both PCR and immunocytochemistry (P-value: 0.003 and 0.024 respectively). LPS level in CRC patients was significantly higher than the control and IBD groups (P values <0.001 and <0.001 respectively). CONCLUSION: TLR4, IgA, EpCAM expression in both CRC and IBD might be related to the pathogenic role of microbiota and could represent potential prevention modalities and therapeutic targets.

Pattern of cognitive impairment among community-dwelling elderly in Egypt and its relation to socioeconomic status.

BACKGROUND: Cognitive decline is one of the aging health problems that strongly affects daily functioning and quality of life of older adults and threatens their independence. The aim of this study was to assess the prevalence and pattern of cognitive impairment (CI) among community-dwelling elderly in Egypt and the contribution of socioeconomic status to inequality in cognitive impairment. METHODS: A cross-sectional study involved 470 community-dwelling elderly aged 60 years or older living in Kafr El-Sheikh Governorate, Egypt. Subjects were recruited from home visits, geriatric clubs, and outpatient clinics. The Montreal Cognitive Assessment tools (MoCA & MoCA-B) were used to assess the prevalence of cognitive impairment, Hachinski ischemic score (HIS) to investigate the type of cognitive impairment, Ain Shams Cognitive Assessment (ASCA) tool to assess the pattern of specific cognitive domain affection, and an Egyptian socioeconomic status (SES) scale to classify the SES of the study participants. RESULTS: The prevalence of cognitive impairment was 50.2% distributed as 37.7% for mild cognitive impairment (MCI) and 12.5% for dementia. The most common type of cognitive impairment was the degenerative type (47.9%). Pattern of specific domain affection among cognitively impaired subjects ranged from 94% for visuospatial function to 12.7% for abstraction. Cognitive impairment was significantly higher with increasing age, female sex, marital status (single or widow), low education, higher number of comorbidities, and positive family history of cognitive impairment (p < 0.001). Also, cognitive impairment was concentrated mainly among participants with low socioeconomic score (p < 0.001). CONCLUSION: In Egypt, cognitive impairment is significantly prevalent and concentrated among those who are in low socioeconomic status. Patients with mild CI were more than those with dementia, and the most common type of CI was the degenerative type. Increasing educational level of low SES population and improving their access to healthcare services are highly recommended to improve the inequity of cognitive impairment.

12-HETE activates Müller glial cells: The potential role of GPR31 and miR-29.

Diabetic retinopathy (DR) is a neurovascular complication of diabetes, driven by an intricate network of cellular and molecular mechanisms. This study sought to explore the mechanisms by investigating the role of 12-hydroxyeicosatetraenoic acid (12-HETE), its receptor GPR31, and microRNA (miR-29) in the context of DR, specifically focusing on their impact on Müller glial cells. We found that 12-HETE activates Müller cells (MCs), elevates glutamate production, and induces inflammatory and oxidative responses, all of which are instrumental in DR progression. The expression of GPR31, the receptor for 12-HETE, was prominently found in the retina, especially in MCs and retinal ganglion cells, and was upregulated in diabetes. Interestingly, miR29 showed potential as a protective agent, mitigating the harmful effects of 12-HETE by attenuating inflammation and oxidative stress, and restoring the expression of pigment epithelium-derived factor (PEDF). Our results underline the central role of 12-HETE in DR progression through activation of a neurovascular toxic pathway in MCs and illuminate the protective capabilities of miR-29, highlighting both as promising therapeutic targets for the management of DR.