The Effect of Zinc Supplementation on Expressed Levels of Peroxisome Proliferator-Activated Receptor Gamma and Glucose Transporter Type 1 Genes in Newborns of Women with Gestational Diabetes Mellitus

Maternal micronutrient disturbance as risks of offspring metabolic syndrome

Metabolic syndrome (MetS) is defined as a constellation of individual metabolic disturbances, including central obesity, hypertension, dyslipidemia, and insulin resistance. The established pathogenesis of MetS varies extensively with gender, age, ethnic background, and nutritional status. In terms of nutritional status, micronutrients are more likely to be discounted as essential components of required nutrition than macronutrients due to the small amount required. Numerous observational studies have shown that pregnant women frequently experience malnutrition, especially in developing and low-income countries, resulting in chronic MetS in the offspring due to the urgent and increasing demands for micronutrients during gestation and lactation. Over the past few decades, scientific developments have revolutionized our understanding of the association between balanced maternal micronutrients and MetS in the offspring. Examples of successful individual, dual, or multiple maternal micronutrient interventions on the offspring include iron for hypertension, selenium for type 2 diabetes, and a combination of folate and vitamin D for adiposity. In this review, we aim to elucidate the effects of maternal micronutrient intake on offspring metabolic homeostasis and discuss potential perspectives and challenges in the field of maternal micronutrient interventions.

Anti-inflammatory mechanisms of polyphenols in adipose tissue: role of gut microbiota, intestinal barrier integrity and zinc homeostasis

Obesity is associated with an imbalance of micro-and macro-nutrients, gut dysbiosis, and a "leaky" gut phenomenon. Polyphenols, such as curcumin, resveratrol, and anthocyanins may alleviate the systemic effects of obesity, potentially by improving gut microbiota, intestinal barrier integrity (IBI), and zinc homeostasis. The essential micronutrient zinc plays a crucial role in the regulation of enzymatic processes, including inflammation, maintenance of the microbial ecology, and intestinal barrier integrity. In this review, we focus on IBI- which prevents intestinal lipopolysaccharide (LPS) leakage - as a critical player in polyphenol-mediated protective effects against obesity-associated white adipose tissue (WAT) inflammation. This occurs through mechanisms that block the movement of the bacterial endotoxin LPS across the gut barrier. Available research suggests that polyphenols reduce WAT and systemic inflammation via crosstalk with inflammatory NF-κB, the mammalian target of rapamycin (mTOR) signaling and zinc homeostasis.

Novel Zinc-Related Differentially Methylated Regions in Leukocytes of Women With and Without Obesity

Introduction

Nutriepigenetic markers are predictive responses associated with changes in “surrounding” environmental conditions of humans, which may influence metabolic diseases. Although rich in calories, Western diets could be linked with the deficiency of micronutrients, resulting in the downstream of epigenetic and metabolic effects and consequently in obesity. Zinc (Zn) is an essential nutrient associated with distinct biological roles in human health. Despite the importance of Zn in metabolic processes, little is known about the relationship between Zn and epigenetic. Thus, the present study aimed to identify the epigenetic variables associated with Zn daily ingestion (ZnDI) and serum Zinc (ZnS) levels in women with and without obesity.

Materials and Methods

This is a case-control, non-randomized, single-center study conducted with 21 women allocated into two groups: control group (CG), composed of 11 women without obesity, and study group (SG), composed of 10 women with obesity. Anthropometric measurements, ZnDI, and ZnS levels were evaluated. Also, leukocyte DNA was extracted for DNA methylation analysis using 450 k Illumina BeadChips. The epigenetic clock was calculated by Horvath method. The chip analysis methylation pipeline (ChAMP) package selected the differentially methylated regions (DMRs).

Results

The SG had lower ZnS levels than the CG. Moreover, in SG, the ZnS levels were negatively associated with the epigenetic age acceleration. The DMR analysis revealed 37 DMRs associated with ZnDI and ZnS levels. The DMR of PM20D1 gene was commonly associated with ZnDI and ZnS levels and was hypomethylated in the SG.

Conclusion

Our findings provide new information on Zn's modulation of DNA methylation patterns and bring new perspectives for understanding the nutriepigenetic mechanisms in obesity.

Changes in PPAR-γ Expression Are Associated with microRNA Profiles during Fetal Programming due to Maternal Overweight and Obesity

BACKGROUND

There has been a global increase in the prevalence of obesity in pregnant women in recent years. Animal studies have shown that intrauterine environment associated with maternal obesity leads to epigenetic changes. However, the effects of epigenetic changes occurring before birth in response to maternal conditions have not been clearly characterized in humans.

OBJECTIVE

The aim of the study was to analyze peroxisome proliferator-activated receptor (PPAR)-γ expression in cell cultures from newborns from mothers with overweight and obesity, in response to in vitro metabolic challenges and their relationship with microRNA profile and cytokine expression. Methods/Study design: The profile of circulating microRNAs from 72 mother-child pairs (including healthy infants born to normal weight [n = 35], overweight [n = 25], and obese [n = 12] mothers) was determined through real-time PCR, and the PPAR-γ expression in peripheral blood mononuclear cell cultures from offspring was analyzed after in vitro challenges.

RESULTS

miR-146a, miR-155, and miR-378a were upregulated in overweight mothers, while miR-378a was upregulated in obese mothers compared to normal weight mothers. In children from overweight mothers, miR-155 and miR-221 were downregulated and miR-146a was upregulated, while offspring of mothers with obesity showed downregulation of miR-155, miR-221, and miR-1301. These microRNAs have direct or indirect relation with PPAR-γ expression. In vitro exposure to high triglyceride and exposure to miR-378a induced a higher expression of PPAR-γ in cells from offspring of mothers with overweight and obesity. In contrast, cells from offspring of mothers with obesity cultured with high glucose concentrations showed PPAR-γ downregulation. IL-1ß, IL-6, and TNF-α expression in cells of offspring of overweight and obese mothers differed from that of offspring of normal weight mothers. Limitation of our study is the small sample size.

CONCLUSION

The blood microRNA profile, and in vitro PPAR-γ and inflammatory cytokine expression in cells of newborn infants are associated with maternal obesity indicating that epigenetic marks may be established during intrauterine development. Key Message: Neonatal microRNA profile is associated with maternal weight. Neonatal microRNA profile is independent of maternal microRNA profile. PPAR-γ expression in newborn cell cultures is affected by maternal weight.

Zinc supplementation for improving pregnancy and infant outcome

BACKGROUND

It has been suggested that low serum zinc levels may be associated with suboptimal outcomes of pregnancy, such as prolonged labour, atonic postpartum haemorrhage, pregnancy-induced hypertension, preterm labour and post-term pregnancies, although these associations have not yet been established. This is an update of a review first published in 1997 and subsequently updated in 2007, 2012 and 2015.

OBJECTIVES

1. To compare the effects on maternal, fetal, neonatal and infant outcomes in healthy pregnant women receiving zinc supplementation versus no zinc supplementation, or placebo. 2. To assess the above outcomes in a subgroup analysis reviewing studies performed in women who are, or are likely to be, zinc-deficient.

SEARCH METHODS

For this update, we searched Cochrane Pregnancy and Childbirth's Trials Register, ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP) (3 July 2020), and reference lists of retrieved studies.

SELECTION CRITERIA

Randomised trials of zinc supplementation versus no zinc supplementation or placebo administration during pregnancy, earlier than 27 weeks' gestation. We excluded quasi-randomised controlled trials. We intended to include studies presented only as abstracts, if they provided enough information or, if necessary, by contacting authors to analyse them against our criteria; we did not find any such studies.

DATA COLLECTION AND ANALYSIS

Three review authors applied the study selection criteria, assessed trial quality and extracted data. When necessary, we contacted study authors for additional information. We assessed the certainty of the evidence using GRADE.

MAIN RESULTS

For this update, we included 25 randomised controlled trials (RCTs) involving over 18,000 women and their babies. The overall risk of bias was low in half of the studies. The evidence suggests that zinc supplementation may result in little or no difference in reducing preterm births (risk ratio (RR) 0.87, 95% confidence interval (CI) 0.74 to 1.03; 21 studies, 9851 participants; low-certainty evidence). Further, zinc supplementation may make little or no difference in reducing the risk of stillbirth (RR 1.22, 95% CI 0.80 to 1.88; 7 studies, 3295 participants; low-certainty evidence), or perinatal deaths (RR 1.10, 95% CI 0.81 to 1.51; 2 studies, 2489 participants; low-certainty evidence). It is unclear whether zinc supplementation reduces neonatal death, because the certainty of the evidence is very low. Finally, for other birth outcomes, zinc supplementation may make little or no difference to mean birthweight (MD 13.83, 95% CI -15.81 to 43.46; 22 studies, 7977 participants; low-certainty evidence), and probably makes little or no difference in reducing the risk of low birthweight (RR 0.94, 95% CI 0.79 to 1.13; 17 studies, 7399 participants; moderate-certainty evidence) and small-for-gestational age babies when compared to placebo or no zinc supplementation (RR 1.02, 95% CI 0.92 to 1.12; 9 studies, 5330 participants; moderate-certainty evidence). We did not conduct subgroup analyses, as very few studies used normal zinc populations.

AUTHORS' CONCLUSIONS

There is not enough evidence that zinc supplementation during pregnancy results in improvements in maternal or neonatal outcomes. Future research to address ways of improving the overall nutritional status of pregnant women, particularly in low-income regions, and not looking at zinc in isolation, should be an urgent priority.

The influence of zinc supplementation on metabolic status in gestational diabetes: a meta-analysis of randomized controlled studies

INTRODUCTION

Zinc supplementation has emerged as an important approach to improve metabolic status in gestational diabetes. However, its use has not been well established. We conduct a systematic review and meta-analysis to evaluate the efficacy of zinc supplementation to improve metabolic status for gestational diabetes.

METHODS

PubMed, Embase, and the Cochrane Central Register of Controlled Trials are searched. Randomized controlled trials (RCTs) assessing the influence of zinc supplementation (or its combination) versus placebo on metabolic status of gestational diabetes are included. Two investigators independently have searched articles, extracted data, and assessed the quality of included studies. Meta-analysis is performed using the random-effect model.

RESULTS

Five RCTs involving 263 patients are included in the meta-analysis. Compared with control intervention for gestational diabetes, zinc supplementation is associated with significantly reduced FPG (std. MD = -0.52; 95% CI = -0.82 to -0.21; p = .0008), insulin (std. MD = -0.68; 95% CI = -0.98 to -0.37; p < .0001), HOMA-IR (std. MD = -0.77; 95% CI = -1.08 to -0.45; p < .00001), and increased QUICKI (std. MD = 0.58; 95% CI = 0.28-0.89; p = .0002) as well as zinc change (std. MD = 0.90; 95% CI = 0.58-1.21; p < .00001), but has no remarkable influence on LDL-cholesterol (std. MD = -0.13; 95% CI = -0.43-0.17; p = .40), and total cholesterol (std. MD = -0.28; 95% CI = -0.63-0.07; p = .11).

CONCLUSIONS

Zinc supplementation is effective to decrease FPG, insulin, HOMA-IR and improve QUICKI in gestational diabetes, but has no significant impact on LDL-cholesterol and total cholesterol.

Nutritional Effects of Zinc on Metabolic Syndrome and Type 2 Diabetes: Mechanisms and Main Findings in Human Studies

Zinc (Zn) plays crucial roles in mammalian metabolism. There is increasing interest about the potential beneficial effects of Zn on the prevention or treatment of non-communicable diseases. This review critically analyzes the information related to the role of Zn on the metabolic syndrome (MetS) as well as type 2 diabetes (T2D), and summarizes the biological basis of these potential effects of Zn. There are several mechanisms by which Zn may help to prevent the development or progression of MetS and T2D, respectively. Zn is involved in both insulin secretion and action in peripheral tissues. Specifically, Zn has insulin-mimetic properties that increase the activity of the insulin signaling pathway. Zn modulates long-chain polyunsaturated fatty acids levels through its action on the absorption of essential fatty acids in the intestine and its subsequent desaturation. Zn is also involved in both the assembly of chylomicrons and lipoproteins as well as their clearance, and thus, plays a role in lipolysis regulation. Finally, Zn has been found to play a role in redox metabolism, and in turn, on blood pressure. The evidence related to the association between Zn status and occurrence of MetS is inconsistent. Although there are several studies reporting an inverse relationship between Zn status or dietary Zn intake and MetS prevalence, others found a direct relationship between Zn status and MetS prevalence. Intervention studies also provide confusing information about this issue, making it hard to reach firm conclusions. Zn as part of the treatment for patients with T2D has been shown to have positive responses in terms of glucose control outcomes, but only among those with Zn deficiency.

The effect of zinc and vitamin E cosupplementation on metabolic status and its related gene expression in patients with gestational diabetes

Objective: The aim of this study was to determine the effects of zinc and vitamin E cosupplementation on metabolic status and gene expression related to insulin and lipid metabolism in women with gestational diabetes mellitus (GDM).Methods: Fifty-four women, in the age range of 18-40 years, diagnosed with GDM were recruited for this randomized, double-blinded, placebo-controlled trial. Subjects were randomly allocated into two intervention groups to either taking 233 mg/day Zinc Gluconate plus 400-IU/day vitamin E supplements or placebo (n = 27 each group) for 6 weeks. Gene expression related to insulin and lipid metabolism was evaluated in peripheral blood mononuclear cells (PBMCs) of women with GDM using RT-PCR method.Results: Participants who received zinc plus vitamin E supplements had significantly lower serum insulin levels (β = -3.81; 95% CI, -5.90, -1.72; p = .001), homeostasis model of assessment-insulin resistance (β = -0.96; 95% CI, -1.54, -0.38; p = .002), serum total-cholesterol (β = -8.56; 95% CI, -16.69, -0.43; p = .03) and low density lipoprotein-cholesterol (LDL)-cholesterol (β = -8.72; 95% CI, -15.27, -2.16; p = .01), and higher quantitative insulin sensitivity check index (β = 0.01; 95% CI, 0.005, 0.02; p = .007) compared with the placebo. Moreover, zinc and vitamin E cosupplementation upregulated gene expression of peroxisome proliferator-activated receptor gamma (PPAR-γ; p = .03) and low-density lipoprotein receptor (LDLR; p = .04) compared with the placebo. Though, zinc and vitamin E combination did not affect other metabolic parameters.Conclusions: Overall, zinc and vitamin E cosupplementation for 6 weeks in women with GDM significantly improved insulin metabolism, lipid profile, and the gene expression levels of PPAR-γ and LDLR.