Circulating spexin levels negatively correlate with age, BMI, fasting glucose, and triglycerides in healthy adult women

Context: Spexin is a newly identified neuropeptide that is involved in satiety control, glucose, and lipids metabolism. It has also been related to human diseases, such as obesity and type 2 diabetes. However, whether spexin changes with age or not is still unclear. Objective: The aim of this study is to investigate the relationship between circulating spexin levels and age and to study their interaction effects on body mass index (BMI), fasting glucose, and -lipids. Design and Participants: This is a cross-sectional study, including 68 healthy adult women whose ages are in a wide range (minimum: 23; median: 38.5; maximum: 64). Outcome Measures: The serum spexin levels were measured by an enzyme-linked immunosorbent assay. Fasting glucose, total cholesterol, triglycerides (TG), alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase, urea, and creatinine were measured by routine biochemical test. Shapiro-Wilk's test, Spearman and Pearson correlation analyses, x² test, and two-way analysis of variance were used to interpret the data. Results: Serum spexin levels are significantly correlated with age (Spearman r = -0.277, P = 0.022), BMI (Spearman r = 20.445, P < 0.001), fasting glucose (Spearman r = 20.302, P = 0.014), and TG (Spearman r = 20.324, P = 0.008). Spexin levels independently predict the risk of high BMI and high fasting glucose. No interaction effects of spexin and age on BMI and fasting glucose were found. Conclusions: Circulating spexin levels decrease with age, suggesting a possible role of this peptide in aging-related functions and disorders. Further investigations are needed to expand the clinical significance of this finding.