Preliminary research on the effects and mechanisms of umbilical cord‑derived mesenchymal stem cells in streptozotocin‑induced diabetic retinopathy

Extracellular vesicles derived from human umbilical cord mesenchymal stem cells relieves diabetic retinopathy through a microRNA-30c-5p-dependent mechanism

AIMS

Extracellular vesicle (EV)-transferred microRNAs (miRNAs) are proved to be potentially therapeutic candidates. Here, we attempted to unveil the role of delivery of miR-30c-5p by human umbilical cord mesenchymal stem cells (hUCMSCs)-derived EVs in diabetic retinopathy (DR).

METHODS

miR-30c-5p and PLCG1 expression in streptozotocin-induced diabetes mellitus (DM) rats and high glucose (HG)-treated human retinal endothelial cells (HRECs) was quantified, followed by analysis on their interaction. EVs were isolated from hUCMSCs and co-cultured with HRECs. Through gain- and loss-of-function assays, the role of hUCMSCs-derived EV containing miR-30c-5p in DR involving PLCG1 and NF-κB pathway was analyzed in vitro and in vivo.

RESULTS

Elevated PLCG1 was found in DM rats and HG-treated HRECs where miR-30c-5p was reduced while increased in hUCMSC-derived EVs. PLCG1 was pinpointed as a target gene of miR-30c-5p, which consequently disrupted the PKC/NF-κB pathway. hUCMSC-derived EVs decreased inflammation reaction by transferring miR-30c-5p in DM rats and HG-treated HRECs. Furthermore, similar changing tendency was observed in HG-treated HRECs induced by overexpressed miR-30c-5p through downregulation of PLCG1 in vivo.

CONCLUSION

Overall, our findings underlined delivery of miR-30c-5p by hUCMSC-derived EVs as a novel suppressor in the inflammatory response following DR.

Intermittent Fasting to the Eye: A New Dimension Involved in Physiological and Pathological Changes

Intermittent fasting (IF) is gaining popularity as a therapeutic dietary strategy that regulates metabolism and can alter the development of metabolic disorders. An increasing amount of research has connected ocular diseases to IF and discovered that it has a direct and indirect effect on the eye’s physiological structure and pathological alterations. This article summarizes the progress of research on IF in regulating the physiological structures of the ocular vasculature, the anterior segment of the eye, the retina, and the choroid. We explored the therapeutic potential of IF for various common ocular diseases. In the future, a comprehensive study into the fundamental processes of IF will provide a direct and rigorous approach to eye disease prevention and therapy.

Nomogram for Prediction of Diabetic Retinopathy Among Type 2 Diabetes Population in Xinjiang, China

PURPOSE

To establish an accurate risk prediction model of diabetic retinopathy (DR) using cost effective and easily available patients' characteristics and clinical biomarkers.

PATIENTS AND METHODS

Totally 18,904 cases diagnosed type 2 diabetes mellitus (T2DM) were collected, among which 13,980 cases were selected after quality screening. The least absolute shrinkage and selection operator (LASSO) regression models were used for univariate analysis and factors selection, and the multi-factor logistic regression analysis was used to establish the prediction model. Discrimination, calibration, and clinical usefulness of the prediction model were assessed using AUC/ Harrell's C statistic, calibration plot, and decision curve analysis. Both the development group and validation group were assessed.

RESULTS

Candidate variables were selected by Lasso regression and multivariate logistic regression analysis. Finally, the candidate predictive variables were included diabetic peripheral neuropathy (DPN), age, neutrophilic granulocyte (NE), high-density lipoprotein (HDL), hemoglobin A1c (HbA1C), duration of T2DM, and glycosylated serum protein (GSP) were used to establish a nomogram model for predicting the risk of DR. In the development group, the area under the receiver operating characteristic curve (AUC) was 0.882 (95% CI, 0.875-0.888). In the validation group, the AUC was 0.870 (95% CI, 0.856-0.881). Meanwhile, the optimism-corrected Harrell's C statistic were 0.878 and 0.867 in the development group and the validation group, respectively. Decision curve analysis demonstrated that the nomogram was clinically useful.

CONCLUSION

We constructed and verified nomograms that could accurately predict the risk of DR in T2DM patients, which could be used to predict the personalized risk of DR patients in Xinjiang, China.

Protective effects of umbilical cord mesenchymal stem cell exosomes in a diabetic rat model through live retinal imaging

AIM

To assess the protective effect of human umbilical cord mesenchymal stem cell exosomes (hucMSC-Exs) in a diabetic rat model by using a variety of retinal bioassays.

METHODS

hucMSCs were subjected to differential ultracentrifugation for the collection of exosomes, and transmission electron microscopy (TEM), nanoparticle tracking analysis (NTA) using a NanoSight analysis system and Western blotting (WB) were used to analyze the expression of surface marker proteins such as CD63, CD9 and Calnexin. Streptozotocin (STZ) was injected into the intraperitoneal cavity to establish a diabetic model. Rats were divided into a normal group, diabetic group and hucMSC-Ex group. Fundus fluorescein angiography (FFA), optical coherence tomography (OCT) and other live imaging methods were used to observe the fundus of the rats. Finally, the eyeballs of rats from each group were collected for hematoxylin-eosin (HE) staining to further analyze the retinal structure.

RESULTS

Through TEM, NTA and WB, we successfully isolated hucMSC-Exs. Subsequent FFA and OCT confirmed that hucMSC-Exs effectively prevented early retinal vascular damage and thickening of the retina. Finally, HE staining of rat retinal sections revealed that exosomes effectively alleviated retinal structure disruption caused by diabetes.

CONCLUSION

hucMSC-Exs have a protective effect on the retina in diabetic rat through FFA, OCT and HE staining.