Circulating Leptin Level, Soluble Leptin Receptor Level and Their Gene Polymorphism in Patients with Systemic Lupus Erythematosus: A Systematic Review and Meta-analysis

Abstract

Initial studies investigating peripheral levels of leptin and soluble leptin receptor (LepR) in systemic lupus erythematosus (SLE) patients have generated a number of controversial results. Thus, we conducted a meta-analysis to evaluate the circulating leptin level, soluble LepR level and related gene polymorphism in SLE patients. We performed a meta-analysis comparing the circulating leptin level, LepR level and their gene polymorphism in patients with SLE to controls, and evaluate the relationship between leptin levels, LepR levels and SLE disease activity. Pubmed, Embase, Cochrane, CNKI, WanFang and VIP databases were searched systematically with no restriction to languages and years (up to Feb. 2020). Stata v. 14.0 was used to calculate statistical data. 34 articles involving 7337 SLE patients and 6866 healthy controls were included in this meta-analysis. Compared with the controls, SLE patients had a significantly higher level of leptin, in particular for active SLE patients, regardless of sample size, source, or assay method. The elevated leptin level was only found in the female SLE group, but not in the male SLE group. Apart from the South American subgroup, other ethnicity subgroups showed significantly higher levels of leptin in SLE patients. A marginally lower level of LepR in SLE patients was also observed. The LepR gene rs1137101 variant (i.e. AG+GG) was borderline significantly associated with the increased risk of SLE. Our meta-analysis revealed thta SLE patients had an elevated leptin level and decreased LepR level. LepR gene rs1137101 mutation might be associated with increased susceptibility to SLE.