Zinc Transporter ZnT1 mRNA Expression Is Negatively Associated with Leptin Serum Concentrations but Is not Associated with Insulin Resistance or Inflammatory Markers in Visceral Adipose Tissue

The aim of this study was to evaluate the relationship between biomarkers of chronic inflammation, insulin resistance, and zinc transporter ZnT1 expression in human visceral adipose tissue. Visceral adipose tissue obtained from 47 adults undergoing laparoscopic surgery for cholecystectomy was used to analyze ZnT1 mRNA expression by RT-qPCR. ZnT1 mRNA levels were compared between subjects with normal weight, overweight, and obesity. A significantly lower ZnT1 expression was observed in overweight and obesity compared with normal-weight subjects (p = 0.0016). Moreover, subjects with normal weight had significantly higher serum zinc concentration (97.7 ± 13.1 mg/L) than subjects with overweight (87.0 ± 12.8 mg/L) and obesity (83.1 ± 6.6 mg/L) (p = 0.002). Pearson test showed a positive correlation between serum zinc concentrations and ZnT1 mRNA expression in visceral adipose tissue (r = 0.323; p = 0.031) and a negative correlation with body mass index (r =  − 0.358; p = 0.013). A linear regression model was used to analyze the associations between ZnT1 mRNA expression and serum zinc levels, insulin resistance (HOMA2-IR), serum adipokines (leptin and adiponectin), and serum inflammation biomarkers (tumor necrosis factor alpha, interleukin-6, and C-reactive protein). Interestingly, leptin concentrations were negatively associated with ZnT1 mRNA expression (p = 0.012); however, no significant associations were found for the rest of the analyzed variables. Future research is needed to analyze the causality of negative association between ZntT1 expression in visceral adipose tissue and leptin.