Association between adipocytokines and diabetic retinopathy: a systematic review and meta-analysis

The potential of serum elabela levels as a marker of diabetic retinopathy: results from a pilot cross-sectional study

Background

The aim of this study is to examine the relationship between elabela (ELA), a recently identified peptide also known as Toddler and Apela, and diabetic retinopathy (DR). ELA, produced in various tissues, acts as a natural ligand for the apelin receptor (APJ). Upon reviewing the existing literature, only one study was found investigating ELA, one of the APJ ligands, in the pathogenesis of DR.

Methods

In our study the patient group comprising individuals diagnosed with type 2 diabetes mellitus (DM), categorized into three subgroups based on detailed fundus examination: those without DR (non-DR) (n = 20), non-proliferative DR (NPDR) (n = 20), and proliferative DR (PDR) (n = 20). A control group (n = 20) consisted of individuals without DM. Blood samples were collected during outpatient clinic admission to measure serum ELA levels, which were determined using a commercial ELISA kit.

Results

The age, sex, and body mass index of the between groups were similar (p = 0.905, 0.985 and 0.241, respectively). The HbA1c levels of the between DM subgroups were similar (p = 0.199). Serum ELA levels were 217.19 ± 97.54 pg/mL in the non-DR group, 221.76 ± 93.12 pg/mL in the NPDR group, 302.35 ± 146.17 pg/mL in the PDR group and 216.49 ± 58.85 pg/mL in the control group. While ELA levels were higher in DM patients compared to the control group, this elevation did not reach statistical significance. Further analysis dividing DM patients into subgroups (non-DR, NPDR, and PDR) revealed higher ELA levels in the PDR group compared to the other subgroups, but this increase was not statistically significant.

Conclusion

Despite the absence of a significant difference in our study, the identification of elevated ELA levels in the PDR group offers valuable insights for future investigations exploring the association between DR and ELA.

Relationship of fibroblast growth factor 21, Klotho, and diabetic retinopathy: a meta-analysis

Background

Diabetic retinopathy (DR) is a serious microvascular complication of diabetes mellitus. Research has identified a close relationship between fibroblast growth factor 21 (FGF21) and DR. FGF21 is a member of the FGF subfamily, which is activated by the Klotho coenzyme involved in the occurrence of DR. However, the association between FGF21, Klotho, and DR remains controversial.

Aim

To assess FGF21 and Klotho levels in patients with DR.

Methods

A literature search of the Web of Science, Wiley Online Library, PubMed, China National Knowledge Infrastructure and Wanfang databases was performed. The title or abstract search terms "diabetic retinopathy" and "DR" were used in combination with "fibroblast growth factor 21", "FGF21", and "Klotho". Meta-analysis results are presented as standardized mean difference (SMD) with corresponding 95% confidence interval (CI).

Results

Fifteen studies were included in this meta-analysis. FGF21 levels in patients with DR were significantly higher than in non-DR patients with diabetes (SMD: 2.12, 95% CI [1.40, 2.84]). Klotho levels in patients with DR were significantly lower than in non-DR patients with diabetes (SMD: -0.63, 95% CI [-1.22, - 0.04]).

Conclusions

This systematic review is the first to evaluate the relationship between FGF21, Klotho levels, and DR. FGF21 levels were significantly higher in patients with DR. Fully elucidating the role of FGF21 will significantly contribute to the treatment of DR.

Role of Perturbated Hemostasis in MASLD and Its Correlation with Adipokines

The prevalence of metabolic dysfunction-associated steatotic liver disease (MASLD) continues to rise, making it one of the most prevalent chronic liver disorders. MASLD encompasses a range of liver pathologies, from simple steatosis to metabolic dysfunction-associated steatohepatitis (MASH) with inflammation, hepatocyte damage, and fibrosis. Interestingly, the liver exhibits close intercommunication with fatty tissue. In fact, adipose tissue could contribute to the etiology and advancement of MASLD, acting as an endocrine organ that releases several hormones and cytokines, with the adipokines assuming a pivotal role. The levels of adipokines in the blood are altered in people with MASLD, and recent research has shed light on the crucial role played by adipokines in regulating energy expenditure, inflammation, and fibrosis in MASLD. However, MASLD disease is a multifaceted condition that affects various aspects of health beyond liver function, including its impact on hemostasis. The alterations in coagulation mechanisms and endothelial and platelet functions may play a role in the increased vulnerability and severity of MASLD. Therefore, more attention is being given to imbalanced adipokines as causative agents in causing disturbances in hemostasis in MASLD. Metabolic inflammation and hepatic injury are fundamental components of MASLD, and the interrelation between these biological components and the hemostasis pathway is delineated by reciprocal influences, as well as the induction of alterations. Adipokines have the potential to serve as the shared elements within this complex interrelationship. The objective of this review is to thoroughly examine the existing scientific knowledge on the impairment of hemostasis in MASLD and its connection with adipokines, with the aim of enhancing our comprehension of the disease.