Sex-Related Effects of Gut Microbiota in Metabolic Syndrome-Related Diabetic Retinopathy

On implications of somatostatin in diabetic retinopathy

Somatostatin, a naturally produced neuroprotective peptide, depresses excitatory neurotransmission and exerts anti-proliferative and anti-inflammatory effects on the retina. In this review, we summarize the progress of somatostatin treatment of diabetic retinopathy through analysis of relevant studies published from February 2019 to February 2023 extracted from the PubMed and Google Scholar databases. Insufficient neuroprotection, which occurs as a consequence of declined expression or dysregulation of retinal somatostatin in the very early stages of diabetic retinopathy, triggers retinal neurovascular unit impairment and microvascular damage. Somatostatin replacement is a promising treatment for retinal neurodegeneration in diabetic retinopathy. Numerous pre-clinical and clinical trials of somatostatin analog treatment for early diabetic retinopathy have been initiated. In one such trial (EUROCONDOR), topical administration of somatostatin was found to exert neuroprotective effects in patients with pre-existing retinal neurodysfunction, but had no impact on the onset of diabetic retinopathy. Overall, we concluded that somatostatin restoration may be especially beneficial for the growing population of patients with early-stage retinopathy. In order to achieve early prevention of diabetic retinopathy initiation, and thereby salvage visual function before the appearance of moderate non-proliferative diabetic retinopathy, several issues need to be addressed. These include the needs to: a) update and standardize the retinal screening scheme to incorporate the detection of early neurodegeneration, b) identify patient subgroups who would benefit from somatostatin analog supplementation, c) elucidate the interactions of somatostatin, particularly exogenously-delivered somatostatin analogs, with other retinal peptides in the context of hyperglycemia, and d) design safe, feasible, low cost, and effective administration routes.

Fennel seeds extract prevents fructose-induced cardiac dysfunction in a rat model of metabolic syndrome via targeting abdominal obesity, hyperuricemia and NF-κβ inflammatory pathway

BACKGROUND

Metabolic syndrome (MetS) is commonly associated with increased risk of cardiac disease that affects a large number of world populations.

OBJECTIVE

This research attempted to investigate the efficacy of fennel seeds extract (FSE) in preventing development of cardiac dysfunction in rats on fructose enriched diet for 3 months, as a model of MetS.

MATERIALS & METHODS

Thirty adult Wistar male rats (160-170 g) were assigned into 5 groups including control, vehicle, FSE (200 mg/kg BW) and fructose (60%) fed rats with and without FSE. Following the last treatment, blood pressure, ECG and heart rate were measured. Next, blood and cardiac tissues were taken for biochemical and histological investigations.

RESULTS

Feeding fructose exhibited characteristic features of MetS involving, hypertension, abnormal ECG, elevated heart rate, serum glucose, insulin, lipids and insulin resistance, accompanied by abdominal obesity, cardiac hypertrophy and hyperuricemia. Fructose fed rats also showed significant reduction in cardiac antioxidants (GSH, SOD, CAT) with elevation in oxidative stress indices (NADPH oxidase, O2.-, H2O2, MDA, PCO), NF-κβ, pro-inflammatory cytokines (TNF-α, IL-1β, IL-6), adhesion molecules (ICAM-1, VCAM-1) and serum cardiac biomarkers (AST, LDH, CK-MB, cTn-I). Histopathological changes evidenced by destruction of cardiac myofibrils, cytoplasmic vacuolization, and aggregation of inflammatory cells were also detected. Consumption of FSE showed high ability to alleviate fructose-induced hypertension, ECG abnormalities, cardiac hypertrophy, metabolic alterations, oxidative stress, inflammation and histological injury.

CONCLUSION

Findings could suggest FSE as a complementary supplement for preventing MetS and associated cardiac outcomes. However, well controlled clinical studies are still needed.

Cardiovascular complications of diabetes: role of non-coding RNAs in the crosstalk between immune and cardiovascular systems

Diabetes mellitus, a group of metabolic disorders characterized by high levels of blood glucose caused by insulin defect or impairment, is a major risk factor for cardiovascular diseases and related mortality. Patients with diabetes experience a state of chronic or intermittent hyperglycemia resulting in damage to the vasculature, leading to micro- and macro-vascular diseases. These conditions are associated with low-grade chronic inflammation and accelerated atherosclerosis. Several classes of leukocytes have been implicated in diabetic cardiovascular impairment. Although the molecular pathways through which diabetes elicits an inflammatory response have attracted significant attention, how they contribute to altering cardiovascular homeostasis is still incompletely understood. In this respect, non-coding RNAs (ncRNAs) are a still largely under-investigated class of transcripts that may play a fundamental role. This review article gathers the current knowledge on the function of ncRNAs in the crosstalk between immune and cardiovascular cells in the context of diabetic complications, highlighting the influence of biological sex in such mechanisms and exploring the potential role of ncRNAs as biomarkers and targets for treatments. The discussion closes by offering an overview of the ncRNAs involved in the increased cardiovascular risk suffered by patients with diabetes facing Sars-CoV-2 infection.