Rbp4, or Retinol-binding protein 4, is a circulating adipokine belonging to the lipocalin family. It acts as a specific carrier protein, delivering retinol (vitamin A) from the liver to peripheral tissues [2]. Rbp4 has gained attention in metabolism research, with its levels being associated with various cardiometabolic diseases.

Elevation in serum levels of Rbp4, often seen in obese experimental animals and human subjects, is linked to cardiometabolic diseases such as obesity, insulin resistance, hyperlipidemia, etc. [1]. In patients with gestational diabetes mellitus (GDM), circulating Rbp4 levels are consistently higher, suggesting its potential as a biomarker for GDM [2]. In type 2 diabetes patients with kidney diseases, Rbp4 levels are significantly higher in those with micro-or macro-albuminuria, and are positively correlated with the albumin-to-creatinine ratio but negatively correlated with the estimated glomerular filtration rate, indicating its potential as a biomarker for kidney diseases in type 2 diabetes [3]. Also, in hyperuricemia-induced rats and patients with hyperuricemia, Rbp4 may be involved in hyperuricemia-induced insulin resistance by inhibiting IRS/PI3K/Akt phosphorylation [4].

In conclusion, Rbp4 plays a crucial role in multiple metabolic processes and is closely associated with various cardiometabolic and related diseases. Studies on Rbp4 contribute to a better understanding of the mechanisms underlying these diseases, potentially providing new targets for treatment.

References:

1. Oluwamodupe, Cecilia, Adeleye, Adesola Oluwaseun. 2023. Targeting Retinol-Binding Protein 4 (RBP4) in the Management of Cardiometabolic Diseases. In Cardiovascular toxicology, 23, 285-294. doi:10.1007/s12012-023-09803-8. https://pubmed.ncbi.nlm.nih.gov/37587250/

2. Leca, Bianca M, Kite, Chris, Lagojda, Lukasz, Randeva, Harpal S, Kyrou, Ioannis. 2024. Retinol-binding protein 4 (RBP4) circulating levels and gestational diabetes mellitus: a systematic review and meta-analysis. In Frontiers in public health, 12, 1348970. doi:10.3389/fpubh.2024.1348970. https://pubmed.ncbi.nlm.nih.gov/38532976/

3. Zhang, Li, Cheng, Yan-Li, Xue, Shuai, Xu, Zhong-Gao. 2020. The Role of Circulating RBP4 in the Type 2 Diabetes Patients with Kidney Diseases: A Systematic Review and Meta-Analysis. In Disease markers, 2020, 8830471. doi:10.1155/2020/8830471. https://pubmed.ncbi.nlm.nih.gov/33082885/

4. Liu, Chan, Zhou, Xiao-Rong, Ye, Mu-Yao, Liu, Hong, Huang, Xian-Zhe. 2021. RBP4 Is Associated With Insulin Resistance in Hyperuricemia-Induced Rats and Patients With Hyperuricemia. In Frontiers in endocrinology, 12, 653819. doi:10.3389/fendo.2021.653819. https://pubmed.ncbi.nlm.nih.gov/34177800/