Elevated serum fetuin-A levels are associated with grades of retinopathy in type 2 diabetic patients

Fetuin-A levels in diabetic retinopathy: a systematic review and meta-analysis

Background

Diabetic retinopathy (DR) is one of the main microvascular complications of diabetes and one of the most common causes of vision loss worldwide. Fetuin-A is a glycoprotein correlated with insulin resistance and has been measured in DR patients. Herein, we aimed to investigate these studies through a systematic review and meta-analysis.

Methods

Four online databases, including PubMed, Embase, Scopus, and the Web of Science were searched comprehensively in order to retrieve relevant studies that compared blood fetuin-A levels in patients with DR vs. non-DR, DR vs. non-diabetic controls, non-DR vs. non-diabetic controls, and proliferative vs. non- proliferative DR. Random-effect meta-analysis was performed for the calculation of the standardized mean difference (SMD) and 95% confidence interval (CI).

Results

From the 186 found results through database search, after eligibility assessment, seven studies were included. A total of 1104 cases with a mean age of 57.24 ± 9.62 years were investigated. Meta-analysis showed that fetuin-A levels were significantly higher in patients with DR compared to both non-DR diabetic patients (SMD 0.41, 95% CI 0.10 to 0.72, P = 0.009), and non-diabetic healthy controls (SMD 0.77, 95% CI 0.47 to 1.07, P < 0.0001). Additionally, patients with proliferative DR had higher fetuin-A levels than those with non-proliferative DR (SMD 0.35, 95% CI 0.11 to 0.59, P = 0.004). However, no significant difference was found between diabetic patients without DR and healthy controls.

Conclusion

Based on our findings, fetuin-A was higher in patients with DR and could be potentially used for measurement in clinical settings if confirmed in future large-scale studies. Moreover, the fact that higher fetuin-A levels were associated with proliferative DR could have clinical implications.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40200-024-01533-0.

Fetuin-B Overexpression Promotes Inflammation in Diabetic Retinopathy Through Activating Microglia and the NF-κB Signaling Pathway

PURPOSE

To investigate the expression, source, role, and mechanism of Fetuin-B (FETUB) in diabetic retinopathy (DR).

METHODS

ELISA and immunofluorescence were used to analyze the concentration of FETUB in plasma, aqueous fluid, and tissue specimens of patients with DR and healthy controls. Immunofluorescence, q-PCR, and western blotting were used to examine the expression of FETUB in DR mice and cells cultured with different concentrations of glucose. BV2 microglia cell line and DR mice were treated using FETUB recombination protein and FETUB shRNA to explore the function of FETUB in DR by q-PCR, western blotting, and immunofluorescence.

RESULTS

FETUB concentrations in plasma, aqueous fluid, and tissue specimens were significantly increased in DR patients. The mice in DR group had a higher concentration of FETUB in the retina and liver tissues than those in the control group, and the expression of FETUB was increased in both ARPE19 and BV2 cells under a high-glucose environment. The ratio of p-P65 (Phospho-P65)/P65 and the expression levels of TNF-α, VEGF, and ionized calcium binding adaptor molecule (IBA)-1 were increased in BV2 cells cultured with FETUB recombinant protein, while they were decreased in BV2 cells transfected with FETUB shRNA. Immunofluorescence staining showed that there were more IBA-1+ activated microglia in the retinas of the FETUB recombination protein group than in the retinas of the DR group, and there were fewer IBA-1+ activated microglia in the retinas of the FETUB shRNA group than in the retinas of the DR group.

CONCLUSIONS

FETUB sourced from endocrine, autocrine, and paracrine pathways could promote inflammation in DR by activating the NF-κB pathway and microglia.

The use of shotgun label-free quantitative proteomic mass spectrometry to evaluate the inflammatory response in aqueous humor from horses with uveitis compared to ophthalmologically healthy horses

OBJECTIVE

The objective of this study was to use shotgun label-free tandem mass spectrometry (LF-MS/MS) to evaluate aqueous humor (AH) from horses with uveitis (UH) compared to ophthalmologically healthy horses (HH).

ANIMALS STUDIED

Twelve horses diagnosed with uveitis based on ophthalmic examination and six ophthalmologically healthy horses (postmortem) purchased for teaching purposes.

PROCEDURES

All horses received a complete ophthalmic examination and physical exam. Aqueous paracentesis was performed on all horses and AH total protein concentrations were measured with nanodrop (TPn) and refractometry (TPr). AH samples were analyzed with shotgun LF-MS/MS and proteomic data were compared between groups using Wilcoxon rank-sum test.

RESULTS

A total of 147 proteins were detected, 11 proteins had higher abundance in UH, and 38 proteins had lower abundance in UH. Proteins with higher abundance included apolipoprotein E, alpha-2-macroglobulin (A2M), alpha-2-HS-glycoprotein, prothrombin, fibrinogen, complement component 4 (C4), joining chain for IgA and IgM, afamin, and amine oxidase. There were positive correlations between TPn (p = .003) and TPr (p = .0001) compared to flare scores.

CONCLUSION

Differential abundance of A2M, prothrombin, fibrinogen, and C4 indicate upregulation of the complement and coagulation cascade in equine uveitis. Proinflammatory cytokines and the complement cascade have potential as therapeutic targets for equine uveitis.

Insights into the liver-eyes connections, from epidemiological, mechanical studies to clinical translation

Maintenance of internal homeostasis is a sophisticated process, during which almost all organs get involved. Liver plays a central role in metabolism and involves in endocrine, immunity, detoxification and storage, and therefore it communicates with distant organs through such mechanisms to regulate pathophysiological processes. Dysfunctional liver is often accompanied by pathological phenotypes of distant organs, including the eyes. Many reviews have focused on crosstalk between the liver and gut, the liver and brain, the liver and heart, the liver and kidney, but with no attention paid to the liver and eyes. In this review, we summarized intimate connections between the liver and the eyes from three aspects. Epidemiologically, we suggest liver-related, potential, protective and risk factors for typical eye disease as well as eye indicators connected with liver status. For molecular mechanism aspect, we elaborate their inter-organ crosstalk from metabolism (glucose, lipid, proteins, vitamin, and mineral), detoxification (ammonia and bilirubin), and immunity (complement and inflammation regulation) aspect. In clinical application part, we emphasize the latest advances in utilizing the liver-eye axis in disease diagnosis and therapy, involving artificial intelligence-deep learning-based novel diagnostic tools for detecting liver disease and adeno-associated viral vector-based gene therapy method for curing blinding eye disease. We aim to focus on and provide novel insights into liver and eyes communications and help resolve existed clinically significant issues.

Evaluation of Fetuin-A level in diabetic retinopathy

Background

Diabetic retinopathy (DR) is a micro-vascular consequence of diabetes mellitus (DM) that manifests clinically as retinal ischemia, neovascularization, altered retinal permeability, and macular edema. In the adult population, DR is now considered a leading cause of blindness. Fetuin-A is a multifunctional glycoprotein that, because of its dual role in insulin resistance and angiogenesis, could be an early trigger of DR pathogenesis.

Objective

This study aimed to evaluate the level of Fetuin-A in diabetic patients with and without retinopathy and demonstrate if it could be used as an early indicator of DR.

Patients and methods

A case–control study enrolled 45 participants selected from Al-Zahraa University Hospital, between March 2021 and October 2021, they were divided into three groups: Group 1: healthy control group (n=15); Group 2: type 2 diabetic patients without DR (n=15); and Group 3: type 2 diabetic patients with DR (n=15). All groups were age- and sex-matched and were investigated by enzyme-linked immunosorbent assay (ELISA) to evaluate serum level of Fetuin-A.

Results

There was a highly significant difference of FBG, 2HPP, and HbA1c between the studied groups (p< 0.001), while there was no significant difference between the three studied groups regarding Fetuin-A. There were no significant correlation between Fetuin-A, glycemic parameters, and diabetic duration in Groups 2 and 3.

Conclusion

Fetuin-A has no significant role in the pathogenesis of diabetic retinopathy.

Dietary Phosphorus as a Marker of Mineral Metabolism and Progression of Diabetic Kidney Disease

Phosphorus is an essential nutrient that is critically important in the control of cell and tissue function and body homeostasis. Phosphorus excess may result in severe adverse medical consequences. The most apparent is an impact on cardiovascular (CV) disease, mainly through the ability of phosphate to change the phenotype of vascular smooth muscle cells and its contribution to pathologic vascular, valvular and other soft tissue calcification. Chronic kidney disease (CKD) is the most prevalent chronic disease manifesting with the persistent derangement of phosphate homeostasis. Diabetes and resulting diabetic kidney disease (DKD) remain the leading causes of CKD and end-stage kidney disease (ESRD) worldwide. Mineral and bone disorders of CKD (CKD-MBD), profound derangement of mineral metabolism, develop in the course of the disease and adversely impact on bone health and the CV system. In this review we aimed to discuss the data concerning CKD-MBD in patients with diabetes and to analyze the possible link between hyperphosphatemia, certain biomarkers of CKD-MBD and high dietary phosphate intake on prognosis in patients with diabetes and DKD. We also attempted to clarify if hyperphosphatemia and high phosphorus intake may impact the onset and progression of DKD. Careful analysis of the available literature brings us to the conclusion that, as for today, no clear recommendations based on the firm clinical data can be provided in terms of phosphorus intake aiming to prevent the incidence or progression of diabetic kidney disease.