The association between retinol-binding protein 4 and risk of type 2 diabetes: A systematic review and meta-analysis

Retinol-binding protein 4 in skeletal and cardiac muscle: molecular mechanisms, clinical implications, and future perspectives

Retinol-binding protein 4 (RBP4) has emerged as a critical adipokine involved in the pathophysiology of metabolic and cardiovascular diseases. Beyond its classical role in retinol transport, RBP4 influences insulin resistance, inflammation, lipid metabolism, mitochondrial function, and cellular apoptosis in both skeletal and cardiac muscles. Elevated levels of RBP4 are associated with obesity, type 2 mellitus diabetes, and cardiovascular diseases, making it a potential biomarker and therapeutic target. This comprehensive review elucidates the molecular mechanisms by which RBP4 affects skeletal and cardiac muscle physiology. We discuss its clinical implications as a biomarker for disease risk and progression, explore therapeutic strategies targeting RBP4, and highlight future research directions. Understanding the multifaceted roles of RBP4 could pave the way for novel interventions against metabolic and cardiovascular disorders.

Retinol-binding protein 4 is a potential biomarker of changes in lean mass in postmenopausal women

Identifying biomarkers can help in the early detection of muscle loss and drive the development of new therapies. Research suggests a potential link between retinol-binding protein 4 (RBP4) and muscle mass, particularly in postmenopausal women. This study aimed to examine the association between baseline RBP4 levels and changes in appendicular lean mass (ALM), an indicator of muscle mass, in postmenopausal women. A 12-month follow-up period (n = 153) included baseline and 12-month ALM assessments using DXA. ALM was normalized to squared height (ALMI). Baseline evaluations encompassed insulin resistance via HOMA-IR and immunoassay magnetic bead panel measurements of RPB4, IL-6, TNF-α, and IL-10. Postmenopausal women were categorized into higher (n = 77) and lower (n = 76) RPB4 groups based on baseline RPB4 values. Their changes in ALMI were compared using Mann-Whitney tests. General linear model was employed to evaluate the predictive power of baseline RBP4 for ALMI changes, adjusting for confounding variables: age, physical activity, smoking status, body fat, HOMA-IR, inflammatory markers (TNF-α and IL-6), and anti-inflammatory factor (IL-10). The higher RBP4 group exhibited a more pronounced reduction in ALMI compared to the lower RBP4 group (Higher RBP4 = -0.39 kg/m2, 95% CI: -0.48 to -0.31 kg/m2vs. Lower RBP4 = -0.24 kg/m2, 95% CI: -0.32 to -0.15 kg/m2, P = 0.011). After adjusting for confounding factors, the association between baseline RBP4 changes and ALMI remained (b = -0.008, SE = 0.002, P < 0.001), indicating higher baseline RBP4 values linked to greater ALMI reduction. Our findings support RBP4 as a potential biomarker for changes in muscle mass in postmenopausal women.

Retinol binding protein 4 and type 2 diabetes: from insulin resistance to pancreatic β-cell function

BACKGROUND AND AIM

Retinol binding protein 4 (RBP4) is an adipokine that has been explored as a key biomarker of type 2 diabetes mellitus (T2DM) in recent years. Researchers have conducted a series of experiments to understand the interplay between RBP4 and T2DM, including its role in insulin resistance and pancreatic β-cell function. The results of these studies indicate that RBP4 has a significant influence on T2DM and is considered a potential biomarker of T2DM. However, there have also been some controversies about the relationship between RBP4 levels and T2DM. In this review, we update and summarize recent studies focused on the relationship between RBP4 and T2DM and its role in insulin resistance and pancreatic β-cell function to clarify the existing controversy and provide evidence for future studies. We also assessed the potential therapeutic applications of RBP4 in treating T2DM.

METHODS

A narrative review.

RESULTS

Overall, there were significant associations between RBP4 levels, insulin resistance, pancreatic β-cell function, and T2DM.

CONCLUSIONS

More mechanistic studies are needed to determine the role of RBP4 in the onset of T2DM, especially in terms of pancreatic β-cell function. In addition, further studies are required to evaluate the effects of drug intervention, lifestyle intervention, and bariatric surgery on RBP4 levels to control T2DM and the role of reducing RBP4 levels in improving insulin sensitivity and pancreatic β-cell function.