Expression of the Zinc Transporters Genes and Metallothionein in Obese Women

Abstract

Research has investigated the participation of zinc transport proteins and metallothionein in the metabolism of this mineral. However, studies about the genetic expression of these proteins in obese patients are scarce. The study determined the expression of zinc transporter protein codifying genes (ZnT-1, Zip-1 and Zip-3) and of metallothionein in 55 obese women, aged between 20 and 56 years. The assessment of body composition was carried out using anthropometric measurements and bioelectrical impedance. Zinc intake was obtained by recording diet over a 3-day period, and the nutritional analysis was carried out using NutWin software version 1.5. The plasmatic and erythrocytary zinc were analyzed by atomic absorption spectrophotometry (λ=213. 9 nm). The determination of mRNA expression of the zinc transporter proteins and metallothionein was carried out using blood, using the RT-PCR method. The mean values of body mass index were 37.9±5.5 kg/m2. The average intake of zinc was 9.4±2.3 mg/day. The analysis of the zinc plasma concentrations showed values of 58.4±10.9 μg/dL. The mean values of zinc in the erythroytes were 38.7±9.1 μg/g Hb. The metallothionein gene had a higher expression in the blood, when compared to zinc transporters ZnT-1, Zip-1, and Zip-3 (p=0.01). The study shows that there are alterations in the biochemical parameters of zinc in obese patients assessed, as well as higher expression of the codifying gene metallothionein, when compared to the investigated zinc transporters.

Zinc, vitamin A, and vitamin C status are associated with leptin concentrations and obesity in Mexican women: results from a cross-sectional study

“…In obese individuals, low ZAG gene expression is associated with low serum adiponectin and high plasma leptin levels, and may play an important role in the development of obesity [43,44]. The influence zinc has on the adipocyte through the expression of leptin, by promoting free fatty acid release and glucose uptake, may also be controlled through the expression of a number of zinc-transporters in the adipocyte, that may be altered in obesity [45,46]. …”

Zinc status is associated with inflammation, oxidative stress, lipid, and glucose metabolism

“…The interaction between zinc status and obesity may be at least partially mediated by obesity-induced modulation of zinc transporters that regulate cellular and intracellular Zn fluxes [ 1 ]. In particular, in obese women, the highest expression was observed for ZnT1 followed by Zip1, whereas no significant expression of Zip3 was found [ 125 ]. It has been revealed that obese patients were characterized by a significantly lower expression of Zip14 in subcutaneous adipose tissue, whereas a 10-week weight loss period significantly increased gene expression.…”

Zinc Supplementation in a Randomized Controlled Trial DecreasedZIP4andZIP8mRNA Abundance in Peripheral Blood Mononuclear Cells of Adult Women

“… 7 Similarly, metallothionein (MT), a ubiquitous cellular zinc storage protein, regulates intracellular zinc by releasing/binding ions through the reduction of the thiol group in the MT protein. 5 , 8 …”

“… 12 , 16 However, assessing the molecular aspects of the cellular biology of zinc using mRNA abundance of zinc transporter proteins and MT in response to zinc supplementation has been suggested as a possible technique for the investigation of zinc status. 8 , 17 …”