Impact of Zinc to Copper Ratio and Lipocalin 2 in Obese Patients Undergoing Sleeve Gastrectomy

Abstract

Worldwide, obesity constitutes a significant health issue. There is the perception that obesity is influenced by subclinical inflammation caused by trace elements (TE). Lipocalin 2 (Lcn2) is an adipokine that is abundantly expressed in adipose tissue, largely in response to metabolic stress; TE deficiency is expressed in metabolic dysfunction as increased oxidative stress, the development of dyslipidaemia and insulin resistance. The primary aim of this study is to explore the relationship between Lcn2 inflammatory biomarkers and the TE status of subjects with morbid obesity who are undergoing laparoscopic sleeve gastrectomy (LSG); the secondary aim is to evaluate the Zn-to-Cu ratio in those with a detected TE deficiency. When this prospective cohort study was conducted, 107 subjects with morbid obesity (i.e., 69 women, 38 men) ranging in age from 20 to 55 years were recruited. Anthropometric measurements and laboratory investigations were performed preoperatively and nine months postoperatively; and blood samples were collected to determine the subjects’ iron, Zn, Cu, Lcn2, and other inflammatory biomarkers. The results revealed 16.82% of the subjects exhibited preoperative Zn deficiency, which increased to 22.43% postoperatively; none of studied subjects exhibited Cu deficiency in the two consecutive measurements; and the 10.28% preoperative prevalence of iron deficiency increased to 15.89% postoperatively. While a negative correlation was observed between the delta body weight change and Lcn2, leptin, and HOMA-IR, a positive correlation was observed between the delta body weight change and the Zn-to-Cu ratio. These findings suggest the existence of preoperative obesity is associated with inflammatory status that may be triggered by TE deficiency and impaired insulin sensitivity; moreover, LSG may accentuate TE deficiency. As such, a patient’s Lcn2 and Zn-to-Cu ratio may be utilized as potential biomarkers of their TE status and metabolic improvement after LSG.