Effects of TNF-α-308G/A Polymorphism on the Risk of Diabetic Nephropathy and Diabetic Retinopathy: An Updated Meta-Analysis

Natural plant medications for the treatment of retinal diseases: The blood-retinal barrier as a clue

BACKGROUND

Retinal diseases significantly contribute to the global burden of visual impairment and blindness. The occurrence of retinal diseases is often accompanied by destruction of the blood‒retinal barrier, a vital physiological structure responsible for maintaining the stability of the retinal microenvironment. However, detailed summaries of the factors damage the blood‒retinal barrier and treatment methods involving natural plant medications are lacking.

PURPOSE

To comprehensively summarize and analyze the protective effects of active substances in natural plant medications on damage to the blood-retina barrier that occurs when retinal illnesses, particularly diabetic retinopathy, and examine their medicinal value and future development prospects.

METHODS

In this study, we searched for studies published in the ScienceDirect, PubMed, and Web of Science databases. The keywords used included natural plant medications, plants, natural herbs, blood retinal barrier, retinal diseases, diabetic retinopathy, age-related macular degeneration, and uveitis. Chinese herbal compound articles, non-English articles, warning journals, and duplicates were excluded from the analysis.

RESULTS

The blood‒retinal barrier is susceptible to high glucose, aging, immune responses, and other factors that destroy retinal homeostasis, resulting in pathological changes such as apoptosis and increased vascular permeability. Existing studies have shown that the active compounds or extracts of many natural plants have the effect of repairing blood-retinal barrier dysfunction. Notably, berberine, puerarin, and Lycium barbarum polysaccharides exhibited remarkable therapeutic effects. Additionally, curcumin, astragaloside IV, hesperidin, resveratrol, ginsenoside Rb1, luteolin, and Panax notoginseng saponins can effectively protect the blood‒retinal barrier by interfering with distinct pathways. The active ingredients found in natural plant medications primarily repair the blood‒retinal barrier by modulating pathological factors such as oxidative stress, inflammation, pyroptosis, and autophagy, thereby alleviating retinal diseases.

CONCLUSION

This review summarizes a series of plant extracts and plant active compounds that can treat retinal diseases by preventing and treating blood‒retinal barrier damage and provides reference for the research of new drugs for treating retinal diseases.

Tumour necrosis factor α-308 G/a and -238 G/a polymorphisms as predicator of diabetic retinopathy in Egyptians

BACKGROUND

Diabetic retinopathy (DR) is a duration dependent serious micro vascular insult of diabetes mellitus. Inflammation has a critical role in the development of early and late stage of DR. Tumour necrosis factor alpha (TNF-α) is an inflammatory cytokine that promoteup regulation of adhesion molecule expression, leukocyte recruitment and monocyte attraction. TNF-α levels are increased in retinas or vitreous of diabetic animals. A cross-sectional, observational study was performed in a sample of diabetic patients who attend diabetes polyclinic of RIO Hospital, Giza, Egypt, between October 2016 and December 2019. Three hundred diabetic patients were studied (150 males and 150 females). 100 diabetic patients without retinopathy, 100 diabetic patients with proliferative retinopathy (PDR), 100diabetic patients with non-proliferative retinopathy (NPDR), also 100 healthy subjects as a control group All patients and subjects were analysed for serum TNF-α levels by ELISA assay and -308 G/A and -238 G/A polymorphism by using Restriction fragment length polymorphisms.

AIM

Evaluating the role of tumour necrosis factor α and -308 G/A, -238 G/A polymorphisms in the pathogenesis of proliferative diabetic retinopathy among Egyptian patients.

RESULTS

A statistically significant increase in TNF-α levels was detected in diabetic without retinopathy, NPDR and PDR groups compared to control group (p > .001). There were no significant different in Genotype and allele frequencies of the -308G/A, and -238 G/A, polymorphisms in both NPDR and PDR. However, the G/G genotype of the -308 G/A polymorphism occurred more frequently in PDR patients with than NPDR patients (0.74% vs 0.68%).

CONCLUSION

The present study clearly demonstrated increased levels of TNF-α, in diabetic patients with diabetic without retinopathy, NPDR and PDR. Furthermore, this study suggested that TNF-α assay could be used as diagnostic tools to predict the initiation and progression of diabetic retinopathy. They could serve as biomarkers not only for an early detection of the disease, but also to monitor the effects of therapy. Also, the G/G genotype of the -308 G/A polymorphism and the G allele of TNF-α gene were more frequent in PDR patients than with NPDR.