Changes in mineral status are associated with improvements in insulin sensitivity in obese patients following L-arginine supplementation

Steviol Glycoside, L-Arginine, and Chromium(III) Supplementation Attenuates Abnormalities in Glucose Metabolism in Streptozotocin-Induced Mildly Diabetic Rats Fed a High-Fat Diet

Stevia rebaudiana Bertoni and its glycosides are believed to exhibit several health-promoting properties. Recently, the mechanisms of the anti-diabetic effects of steviol glycosides (SG) have been the subject of intense research. The following study aims to evaluate the results of SG (stevioside (ST) and rebaudioside A (RA)) combined with L-arginine (L-Arg) and chromium(III) (CrIII) supplementation in streptozotocin- (STZ) induced mild type 2 diabetic rats fed a high-fat diet (HFD), with particular emphasis on carbohydrate and lipid metabolisms. The experiment was carried out on 110 male Wistar rats, 100 of which were fed an HFD to induce insulin resistance, followed by an intraperitoneal injection of streptozotocin to induce mild type 2 diabetes. After confirmation of hyperglycemia, the rats were divided into groups. Three groups served as controls: diabetic untreated, diabetic treated with metformin (300 mg/kg BW), and healthy group. Eight groups were fed an HFD enriched with stevioside or rebaudioside A (2500 mg/kg BW) combined with L-arginine (2000 or 4000 mg/kg BW) and Cr(III) (1 or 5 mg/kg BW) for six weeks. The results showed that supplementation with SG (ST and RA) combined with L-arg and Cr(III) could improve blood glucose levels in rats with mild type 2 diabetes. Furthermore, ST was more effective in improving blood glucose levels, insulin resistance indices, and very low-density lipoprotein cholesterol (VLDL-C) concentrations than RA. Although L-arg and Cr(III) supplementation did not independently affect most blood carbohydrate and lipid indices, it further improved some biomarkers when combined, particularly with ST. Notably, the beneficial impact of ST on the homeostatic model assessment–insulin resistance (HOMA-IR) and on the quantitative insulin-sensitivity check index (QUICKI) was strengthened when mixed with a high dose of L-arg, while its impact on antioxidant status was improved when combined with a high dose of Cr(III) in rats with mild type 2 diabetes. In conclusion, these results suggest that supplementary stevioside combined with L-arginine and Cr(III) has therapeutic potential for mild type 2 diabetes. However, further studies are warranted to confirm these effects in other experimental models and humans.

The Potential of L-Arginine in Prevention and Treatment of Disturbed Carbohydrate and Lipid Metabolism—A Review

L-arginine, an endogenous amino acid, is a safe substance that can be found in food. The compound is involved in synthesis of various products responsible for regulatory functions in the body. Particularly noteworthy is, among others, nitric oxide, a signaling molecule regulating carbohydrate and lipid metabolism. The increasing experimental and clinical data indicate that L-arginine supplementation may be helpful in managing disturbed metabolism in obesity, regulate arterial blood pressure or alleviate type 2 diabetes symptoms, but the mechanisms underlying these effects have not been sufficiently elucidated. This review aims to present the up-to-date information regarding the current uses and health-promoting potential of L-arginine, its effects on nitric oxide, carbohydrate and lipid metabolisms, based on the results of in vivo, in vitro studies, and clinical human trials. Available literature suggests that L-arginine may have beneficial effects on human health. However, some studies found that higher dietary L-arginine is associated with worsening of an existing disease or may be potential risk factor for development of some diseases. The mechanisms of regulatory effects of L-arginine on carbohydrate and lipid metabolism have not been fully understood and are currently under investigation.

Paracrine Role of the Endothelium in Metabolic Homeostasis in Health and Nutrient Excess

The vascular endothelium traditionally viewed as a simple physical barrier between the circulation and tissue is now well-established as a key organ mediating whole organism homeostasis by release of a portfolio of anti-inflammatory and pro-inflammatory vasoactive molecules. Healthy endothelium releases anti-inflammatory signaling molecules such as nitric oxide and prostacyclin; in contrast, diseased endothelium secretes pro-inflammatory signals such as reactive oxygen species, endothelin-1 and tumor necrosis factor-alpha (TNFα). Endothelial dysfunction, which has now been identified as a hallmark of different components of the cardiometabolic syndrome including obesity, type 2 diabetes and hypertension, initiates and drives the progression of tissue damage in these disorders. Recently it has become apparent that, in addition to vasoactive molecules, the vascular endothelium has the potential to secrete a diverse range of small molecules and proteins mediating metabolic processes in adipose tissue (AT), liver, skeletal muscle and the pancreas. AT plays a pivotal role in orchestrating whole-body energy homeostasis and AT dysfunction, characterized by local and systemic inflammation, is central to the metabolic complications of obesity. Thus, understanding and targeting the crosstalk between the endothelium and AT may generate novel therapeutic opportunities for the cardiometabolic syndrome. Here, we provide an overview of the role of the endothelial secretome in controlling the function of AT. The endothelial-derived metabolic regulatory factors are grouped and discussed based on their physical properties and their downstream signaling effects. In addition, we focus on the therapeutic potential of these regulatory factors in treating cardiometabolic syndrome, and discuss areas of future study of potential translatable and clinical significance. The vascular endothelium is emerging as an important paracrine/endocrine organ that secretes regulatory factors in response to nutritional and environmental cues. Endothelial dysfunction may result in imbalanced secretion of these regulatory factors and contribute to the progression of AT and whole body metabolic dysfunction. As the vascular endothelium is the first responder to local nutritional changes and adipocyte-derived signals, future work elucidating the changes in the endothelial secretome is crucial to improve our understanding of the pathophysiology of cardiometabolic disease, and in aiding our development of new therapeutic strategies to treat and prevent cardiometabolic syndrome.

Therapeutic advances in overcoming intrauterine growth restriction induced metabolic syndrome

Intrauterine growth restriction (IUGR) remains a great public health challenge as it affects neonatal survival and influences their normal biological development and metabolism. Several clinical researches have revealed the occurrence of metabolic syndrome, such as insulin resistance, obesity, type 2 diabetes mellitus, oxidative stress, dyslipidemia, as direct results of IUGR. Therefore, it is essential to understand its underlying mechanism, impact and develop effective therapies. The purpose of this work is to review the current knowledge on IUGR induced metabolic syndrome and relevant therapies. Here in, we elaborate on the characteristics and causes of IUGR by pointing out recent research findings. Furthermore, we discuss the impact of IUGR on different organs of the body, followed by preclinical studies on IUGR using suitable animal models. Additionally, various metabolic disorders with their genetic implications, such as insulin resistance, type 2 diabetes mellitus, dyslipidemia, obesity are detailed. Finally, the current therapeutic options used in the treatment of IUGR are summarized with some prospective therapies highlighted.

Perturbation of serum metabolome in relation to type 2 diabetes mellitus and urinary levels of phthalate metabolites and bisphenols

BACKGROUND

Emerging evidence has proved the associations between exposure to phthalates (PAEs) and bisphenols and type 2 diabetes mellitus (T2DM), but the underlying mechanisms for these associations are poorly understood. Metabolomics is a powerful tool to identify differential metabolites and metabolic pathways related to diseases and chemical exposure, which may reveal underlying mechanisms. However, little is known about the roles of metabolism in the associations for PAE and bisphenol exposure with T2DM.

OBJECTIVES

The purpose of the study was to investigate the roles of metabolism in the associations for exposure to PAEs and bisphenols with T2DM.

METHODS

In this study, 60 T2DM cases and 60 controls, who were matched in age, sex, and body mass index (BMI), were selected from the total study population in our previous studies. Fasting blood and spot urine samples of the volunteers were used for non-targeted metabolomics analysis and determination of phthalate metabolites (mPAEs) and bisphenols, respectively. The associations of urinary mPAEs and bisphenols with screened metabolic biomarkers in metabolomics analysis were analyzed using multiple linear regression models.

RESULTS

Based on non-targeted metabolomics, 19 serum metabolic biomarkers were screened between T2DM cases and controls, mostly related to galactose metabolism, amino acid metabolism, and pyrimidine metabolism. More than half of mPAEs were mostly positively associated with up-regulated metabolic biomarkers and negatively associated with down-regulated biomarkers. Different from PAEs, no evident results suggested the roles of metabolism in the associations between bisphenol exposure and T2DM.

CONCLUSIONS

Combined with the positive associations between most urinary mPAEs and T2DM in our previous study, our findings indicated that PAE exposure may contribute to T2DM risk through disturbing galactose metabolism, amino acid metabolism (especially arginine biosynthesis and alanine, aspartate and glutamate metabolism), and pyrimidine metabolism.

Effects of brown seaweeds on postprandial glucose, insulin and appetite in humans - A randomized, 3-way, blinded, cross-over meal study

BACKGROUND & AIMS

Seaweed including brown seaweeds with rich bioactive components may be efficacious for a glycaemic management strategy and appetite control. We investigated the effects of two brown edible seaweeds, Laminaria digitata (LD) and Undaria pinnatifida (UP), on postprandial glucose metabolism and appetite following a starch load in a human meal study.

METHODS

Twenty healthy subjects were enrolled in a randomized, 3-way, blinded cross-over trial. The study was registered under ClinicalTrials.gov Identifier no. NCT00123456. At each test day, the subjects received one of three meals comprising 30 g of starch with 5 g of LD or UP or an energy-adjusted control meal containing pea protein. Fasting and postprandial blood glucose, insulin, C-peptide and glucagon-like peptide-1 (GLP-1) concentrations were measured. Subjective appetite sensations were scored using visual analogue scales (VAS).

RESULTS

Linear mixed model (LMM) analysis showed a lower blood glucose, insulin and C-peptide response following the intake of LD and UP, after correction for body weight. Participants weighing ≤ 63 kg had a reduced glucose response compared to control meal between 40 and 90 min both following LD and UP meals. Furthermore, LMM analysis for C-peptide showed a significantly lower response after intake of LD. Compared to the control meal, GLP-1 response was higher after the LD meal, both before and after the body weight adjustment. The VAS scores showed a decreased appetite sensation after intake of the seaweeds. Ad-libitum food intake was not different three hours after the seaweed meals compared to control.

CONCLUSIONS

Concomitant ingestion of brown seaweeds may help improving postprandial glycaemic and appetite control in healthy and normal weight adults, depending on the dose per body weight.

CLINICAL TRIAL REGISTRY NUMBER

Clinicaltrials.gov (ID# NCT02608372).

Effects of L-arginine supplementation on biomarkers of glycemic control: a systematic review and meta-analysis of randomised clinical trials

The present meta-analysis aimed to determine the effectiveness of L-arginine supplementation in improving biomarkers of glycemic control in adults. Electronic databases including PubMed, ISI Web of Science, Scopus, and the Cochrane Collaboration Library were searched up to January 2020. The meta-analysis of twelve randomised clinical trials indicated that L-arginine had no significant effect on serum fasting blood sugar (FBS) (weighted mean difference [WMD]: -3.38 mg/dl, 95% CI: -6.79 to 0.04, p = .53), serum insulin (WMD: -0.12 Hedges' g 95% CI: -0.33 to 0.09, p = .27), glycated haemoglobin A1c (HbA1c; WMD: -0.04%, 95% CI: -0.25 to 0.17, p = .71), and homeostasis model assessment for insulin resistance (WMD: -0.48, 95% CI: -1.15 to 0.19, p = .15). Although several animal studies have proposed that L-arginine supplementation might improve blood glucose control, the present study could not confirm this benefit in humans.

Associations of Arginine with Gestational Diabetes Mellitus in a Follow-Up Study

In the reported study we applied the targeted metabolomic profiling employing high pressure liquid chromatography coupled with triple quadrupole tandem mass spectrometry (HPLC–MS/MS) to understand the pathophysiology of gestational diabetes mellitus (GDM), early identification of women who are at risk of developing GDM, and the differences in recovery postpartum between these women and normoglycemic women. We profiled the peripheral blood from patients during the second trimester of pregnancy and three months, and one year postpartum. In the GDM group Arg, Gln, His, Met, Phe and Ser were downregulated with statistical significance in comparison to normoglycemic (NGT) women. From the analysis of the association of all amino acid profiles of GDM and NGT women, several statistical models predicting diabetic status were formulated and compared with the literature, with the arginine-based model as the most promising of the screened ones (area under the curve (AUC) = 0.749). Our research results have shed light on the critical role of arginine in the development of GDM and may help in precisely distinguishing between GDM and NGT and earlier detection of GDM but also in predicting women with the increased type 2 diabetes mellitus (T2DM) risk.

The association between serum omentin level and bodyweight: A systematic review and meta-analysis of observational studies

BACKGROUND AND AIMS

A number of studies have examined the association between omentin and body weight, but the findings have been inconclusive. Here in, we systematically reviewed available observational studies to elucidate the overall relationship between omentin and body weight, by comparison of serum omentin level in overweight/obese and normal weight subjects.

METHODS

PubMed, Science direct, Scopus and ISI web of science databases were searched for all available literature until January 2020 for studies assessing the association between omentin and body weight. The Newcastle-Ottawa Quality Assessment Scale was used to assess the quality of each study.

RESULTS

A total of 27 articles met the inclusion criteria and were included in our systematic review and meta-analysis. There was a significant association between omentin serum level and body weight (Standard Mean Difference (SMD) -0.43; 95% CI, -0.70 to -0.15; P = 0.002; I² = 93.2%). In order to find the probable source of heterogeneity subgroup analysis based on the participants' age (adolescent, adult), gender (male, female, both gender), health status (healthy, unhealthy), geographical location (Asian, non-Asian countries), study quality (low, medium, high), study design (case-control, cross-sectional), participants' health status (healthy, unhealthy) and BMI (obese, overweight) was carried out.

CONCLUSION

According to what was discussed, we found that serum omentin level is significantly lower in overweight subjects but not obese ones. This finding should be interpreted cautiously because of significant heterogeneity among included studies.

An electrochemical impedimetric sensing platform based on a peptide aptamer identified by high-throughput molecular docking for sensitive l-arginine detection

As a primary building block for protein synthesis, l-arginine (l-Arg) is also a precursor for the synthesis of important metabolites, and is involved in various physiological and pathophysiological processes. l-Arg is a potential biomarker in clinical diagnosis and nutritional status assessment, making it valuable to quantify and monitor this biomolecule. In this study, peptide aptamers that specifically interact with l-Arg were identified by high-throughput molecular docking, and the binding capacities between the synthesized peptide aptamers and l-Arg were then measured by isothermal titration calorimetry. We hypothesized that the peptide aptamer with the greatest binding capacity could be used as the recognition element in a biosensor. A chemosynthetic peptide aptamer modified with mercaptan and spacer units (thioctic acid-GGGG-FGHIHEGY) was thus used to construct label-free electrochemical impedimetric biosensors for l-Arg based on gold electrodes. The optimum biosensor showed good sensitivity to l-Arg with a linear range of 0.1 pM-0.1 mM, and the calculated limit of detection (three times the signal-to-noise ratio) was 0.01 pM. Interference studies and assays of diluted serum samples were also carried out, and satisfactory results obtained. In conclusion, a potential method of peptide aptamer screening and biosensor fabrication for detecting small biological molecules was demonstrated.

Effects of l-arginine supplementation on glycemic profile: Evidence from a systematic review and meta-analysis of clinical trials

BACKGROUND

The effects of l-arginine supplementation on indices of glycemic control and the role of many factors influencing this intervention have been controversial in clinical trials.

OBJECTIVE

This meta-analysis was performed to assess the effects of l-arginine supplementation on indices of glycemic control, including fasting blood glucose (FBG), hemoglobin A1c (HbA1c), serum insulin and homeostatic model assessment of insulin resistance (HOMA-IR) levels in randomized controlled trials (RCTs).

SEARCH STRATEGY

This study conducted a systematic review of RCTs published in PubMed, Scopus, Web of Science, Cochrane Library and Embase, up to 5 May, 2018.

INCLUSION CRITERIA

Studies were included in this meta-analysis if they were RCTs with parallel design and reported sufficient data on participants before and after intervention, and outcomes of glycemic profile parameters in both the arginine supplementation and control groups.

DATA EXTRACTION AND ANALYSIS

The screening of titles and abstracts was performed independently by two reviewers. Selected articles were considered if they met the study's inclusion criteria. The quality of included studies was assessed by using the Cochrane Collaboration modified tool. From 710 articles retrieved in the initial search, only 10 trials were suitable for pooling the effects of arginine supplementation on serum glucose, insulin, HOMA-IR and HbA1c levels, with effect sizes of nine, eight, five and five, respectively.

RESULTS

Pooled random-effect analysis revealed that l-arginine supplementation could significantly decrease FBG level (weighted mean difference [WMD]: 3.35 mg/dL; 95% confidence interval [CI] = [-6.55, -0.16]; P = 0.04) and serum insulin level (WMD: -2.19 μIU/mL; 95% CI = [-3.70, -0.67]; P = 0.005). However, the effects of l-arginine supplementation on HOMA-IR and HbA1c were not significant. Results of subgroup analysis showed that supplementation with l-arginine could significantly decrease serum insulin levels when the dosage of l-arginine is > 6.5 g/d (WMD: -3.49 μIU/mL; 95% CI = [-5.59, -1.38]; P = 0.001), when the duration of supplementation is ≤ 12.8 weeks (WMD: -3.76; 95% CI = [-6.50, -0.98]; P = 0.008), when the participants are not diabetic patients (WMD: -2.54 μIU/mL; 95% CI = [-4.50, -0.50]; P = 0.01) and when the baseline serum level of insulin was > 20 μIU/mL (WMD: -3.98; 95% CI = [-6.31, -1.65]; P = 0.001).

CONCLUSION

Although the results of this study confirmed that supplementation with l-arginine could have significant effects on some glycemic profile indices of participants in clinical trials, the clinical importance of this reduction may not be meaningful.

Role of Zinc in Zinc-α2-Glycoprotein Metabolism in Obesity: a Review of Literature

Excessive adipose tissue promotes the manifestation of endocrine disorders such as reduction of the secretion of zinc-α2-glycoprotein (ZAG), an adipokine with anti-inflammatory and lipid-mobilizing activity. The molecular structure of this adipokine includes binding sites for zinc, a trace element with important antioxidant and immunological proprieties that also participates in energy metabolism and stimulates the function of ZAG. The objective of this review is to highlight current data on the metabolism of ZAG in obesity and the role of zinc in this process. The identified studies show that subjects with obesity have low serum concentrations of zinc and ZAG, as well as low expression of the genes encoding this protein. Thus, zinc appears to be an important regulator of the homeostasis of ZAG in the body; however, alterations in the metabolism of zinc in obesity appear to compromise the functions of ZAG. Therefore, further studies are needed to clarify the relationship between zinc and ZAG metabolism and its repercussions in obesity.

No association between zinc and thyroid activity in obese women

Obesity is characterized by changes in the metabolism of zinc and thyroid hormones. Studies have also shown the role of zinc in the function and metabolism of thyroid. The present study aimed to evaluate the relationship between serum concentrations of thyroid hormones, dietary zinc intake and zinc distribution in obese women. A case-control study was conducted enrolling 98 women aged between 20 and 50 years old who were divided into case group (BMI ≥ 35 kg/m²) and control group (BMI = 18.5-24.9 kg/m²). Patients underwent anthropometric measurements and analysis of dietary zinc intake, which was performed by a three-day food record. Zinc concentrations in plasma and erythrocytes were determined by inductively coupled plasma optical emission spectrometry. Serum concentrations of thyroid hormones and antibodies were determined by chemiluminescence. Mean values of dietary zinc intake were higher than recommended (10.37 ± 3.12 mg/day and 11.37 ± 4.36 mg/day for control and obeses, respectively). Obese women had reduced plasma (67.22 ± 5.96 μg/dL) and erythrocyte (37.16 ± 3.64 μg Zn/gHb) zinc concentrations when compared to the control group (plasma: 89.71 ± 13.33 μg/dL; erythrocyte: 42.68 ± 3.73 μg Zn/gHb) (p < 0.001). Serum TSH (control: 2.62 ± 1.29 μIU/mL; obeses: 3.08 ± 1.13 μIU/mL), Free T3 (control: 2.19 ± 0.63 pg/dL; obeses: 2.09 ± 0.34 pg/dL), and Free T4 (control: 1.12 ± 0.31 ng/dL; obeses: 1.09 ± 0.19 ng/dL) concentrations were within the normal range in both groups, without significant difference between them (p > 0.05). There was no correlation between thyroid hormone concentrations and zinc parameters (p > 0.05). Although obese women presented hypozincemia, they had normal levels of thyroid hormones and no correlation was found between the studied parameters.

The effect of L-arginine supplementation on obesity-related indices: A systematic review and meta-analysis of randomized clinical trials

The clinical studies regarding the effect of L-arginine in human anthropometry have not been fully consistent, therefore, we carried out a systematic review and meta-analysis of randomized clinical trials in order to precisely evaluate and quantify the efficacy of L-arginine on weight, waist circumference, and BMI. We searched online databases including PubMed, SCOPUS, and Google Scholar for relevant articles up to September 2017. Eligible articles were reviewed by two independent investigators. Mean differences of the outcomes were used for calculation of weighted mean difference (WMD) derived from the random-effects model. Statistical heterogeneity between studies was examined using Cochran's Q-test and I² index. Funnel plot and Egger's tests were performed to assess the publication bias. In our initial search, we found 1598 publications, of which 8 RCTs (9 treatment arms) were included. The results of the meta-analysis displayed a significant reduction in WC following L-arginine supplementation (WMD: -2.97 cm; 95% CI: -4.75 to -1.18, P = 0.001). However, L-arginine intervention had not elicited a significant effect on BMI (WMD: -0.51 kg/m²; 95% CI: -1.11 to .08, P = 0.09) and body weight (WMD: -0.57 kg; 95% CI: -1.77 to 0.61, P = 0.34). Subgroup analyses displayed that longer-term interventions (≥8 weeks) had a positive effect on body weight and using < 8 g/day L-arginine with longer duration (≥8 weeks) could significantly decrease BMI. In conclusion, this meta-analysis result suggested L-arginine supplementation could reduce waist circumference without any significant effect on body weight and body mass index.

Review shows that maternal obesity induces serious adverse neonatal effects and is associated with childhood obesity in their offspring

AIM

Obesity at the start of pregnancy has been rising worldwide, increasing the risk of maternal complications. We reviewed the independent effects of maternal obesity during pregnancy on neonatal adverse outcomes and the risk of childhood obesity and adverse cardio-metabolic profiles.

METHODS

We searched MEDLINE for papers published in English between December 2007 and November 2017, focusing primarily on human studies published in the last five years. However, we also chose to highlight examples derived from model animals that could bring mechanistic insight and preventive and therapeutic avenues.

RESULTS

Our review showed that maternal obesity had independent effects on neonatal adverse outcomes such as macrosomia, perinatal mortality and birth defects. Maternal obesity alone increased the risks for adverse neonatal outcomes, including macrosomia, perinatal mortality, induced preterm birth and birth defects. In association with excess gestational weight gain, mainly early in pregnancy, increased the risks of childhood obesity, higher fat mass and, to a smaller extent, adverse cardio-metabolic profiles. Animal models highlighted sexually dimorphic responses to maternal obesity.

CONCLUSION

Maternal obesity induced serious adverse neonatal effects and was associated with childhood obesity in their offspring. The peri-conceptional period is critical for metabolic programming, and obese women need close monitoring from conception.

Effect of hypotensive therapy combined with modified diet or zinc supplementation on biochemical parameters and mineral status in hypertensive patients

BACKGROUND

Hypotensive therapy leads to a number of trace elements metabolism disturbances. Zinc balance is frequently affected by antihypertensive treatment.

AIM

To evaluate the effect of a hypotensive treatment, modified diet and zinc supplementation on mineral status and selected biochemical parameters in newly diagnosed hypertensive patients on monotherapy.

METHODS

In the first stage, arterial hypertension in ninety-eight human subjects was diagnosed. In the second stage, antihypertensive monopharmacotherapy was implemented. In the third stage, patients were randomized into three groups and continued antihypertensive monotherapy: group D received an optimal-mineral-content diet, group S received zinc supplementation, and group C had no changes in diet or zinc supplementation. Iron, zinc, and copper concentrations in serum, erythrocytes, urine, and hair were determined. Lipids, glucose, ceruloplasmin, ferritin, albumin, C-reactive protein (CRP), tumor necrosis factor α (TNF-α), nitric oxide (NO), superoxide dismutase (SOD) and catalase (CAT) were assayed in serum.

RESULTS

Antihypertensive monotherapy decreased zinc concentration in serum and erythrocytes and increased the level of zinc in urine, decreased CAT and SOD activity, TNF-α concentration in serum, and increased the level of NO in the serum. Zinc supply led to an increase in zinc concentration in serum, erythrocytes, and hair (in group S only). In the groups with higher zinc intake, decreased glucose concentration in the serum was observed. Significant correlation was seen between the zinc and glucose serum concentrations.

CONCLUSION

Hypotensive drugs disturb zinc status in newly diagnosed hypertensive patients. Antihypertensive monotherapy combined with increased zinc supply in the diet or supplementation favorably modify zinc homeostasis and regulate glucose status without blood pressure affecting in patients with hypertension.

Short-term l-arginine supplementation attenuates elevation of interleukin 6 level after resistance exercise in overweight men

BACKGROUND AND AIM

l-Arginine (l-arg) supplementation and resistance exercise can induce changes in inflammatory and anti-inflammatory cytokines; however, it has not been investigated in obese hypertensive men. This study examines the effects of short-term l-arg supplementation and acute resistance exercise (AREX) on cytokine levels in obese hypertensive men.

METHODS

Eight obese hypertensive men aged 46 ± 6 yrs. with an average body weight of 92.56 ± 9.9 kg and a BMI of 31.68 ± 2.18 kg/m² participated in a randomized, double-blinded, crossover study. The patients were distributed into exercise groups based on the type of supplementation (6 g/day of placebo or l-arg for 7 days). Supplementation periods were separated by a seven-day washout period. The AREX regimen consisted of eight exercises with an exercise intensity of 60% of 1 repetition maximum. The interleukins IL-1ra, IL-6, and IL-10 and the IL-6/IL10 ratio were determined at rest, immediately after exercise and 1 h after exercise sessions.

RESULTS

IL-1ra levels exhibited a significant difference both immediately and 1 h after exercise when the l-arg and placebo groups were compared (P < 0.05). IL-6 levels increased significantly after exercise in the placebo group compared with the l-arg group (P < 0.05). The placebo group showed a decrease in the IL-10 levels 1 h after exercise compared with resting levels (P < 0.05). The IL-6/IL-10 ratio showed a statistically significant increase in the placebo group after exercise compared to the l-arg group (P < 0.05).

CONCLUSIONS

LARG supplementation attenuates the cytokine increase after AREX, in particular peak IL-6 levels decrease and exercise induced decreases in IL-10 levels are attenuated.

Nitric oxide bioavailability dysfunction involves in atherosclerosis

The pathological characteristics of atherosclerosis (AS) include lipid accumulation, fibrosis formation and atherosclerotic plaque produced in artery intima, which leads to vascular sclerosis, lumen stenosis and irritates the ischemic changes of corresponding organs. Endothelial dysfunction was closely associated with AS. Nitric oxide (NO) is a multifunctional signaling molecule involved in the maintenance of metabolic and cardiovascular homeostasis. NO is also a potent endogenous vasodilator and enters for the key processes that suppresses the formation vascular lesion even AS. NO bioavailability indicates the production and utilization of endothelial NO in organisms, its decrease is related to oxidative stress, lipid infiltration, the expressions of some inflammatory factors and the alteration of vascular tone, which plays an important role in endothelial dysfunction. The enhancement of arginase activity and the increase in asymmetric dimethylarginine and hyperhomocysteinemia levels all contribute to AS by intervening NO bioavailability in human beings. Diabetes mellitus, obesity, chronic kidney disease and smoking, etc., also participate in AS by influencing NO bioavailability and NO level. Here, we reviewed the relationship between NO bioavailability and AS according the newest literatures.

Zinc and Oxidative Stress: Current Mechanisms

Oxidative stress is a metabolic dysfunction that favors the oxidation of biomolecules, contributing to the oxidative damage of cells and tissues. This consequently contributes to the development of several chronic diseases. In particular, zinc is one of the most relevant minerals to human health, because of its antioxidant properties. This review aims to provide updated information about the mechanisms involved in the protective role of zinc against oxidative stress. Zinc acts as a co-factor for important enzymes involved in the proper functioning of the antioxidant defense system. In addition, zinc protects cells against oxidative damage, acts in the stabilization of membranes and inhibits the enzyme nicotinamide adenine dinucleotide phosphate oxidase (NADPH-Oxidase). Zinc also induces the synthesis of metallothioneins, which are proteins effective in reducing hydroxyl radicals and sequestering reactive oxygen species (ROS) produced in stressful situations, such as in type 2 diabetes, obesity and cancer. Literature provides strong evidence for the role of zinc in the protection against oxidative stress in several diseases.

Effect of Spirulina maxima Supplementation on Calcium, Magnesium, Iron, and Zinc Status in Obese Patients with Treated Hypertension

The effects of Spirulina maxima supplementation on calcium, magnesium, iron, and zinc status were studied in a double-blind placebo-controlled trial of 50 obese subjects with treated hypertension, each randomized to receive 2 g of spirulina or a placebo daily for 3 months. At baseline and after treatment, the calcium, magnesium, iron, and zinc concentration in plasma was assessed. It was found that 3 months of S. maxima supplementation resulted in a significant decrease in the iron level in the plasma of obese patients. In conclusion, this is the first clinical study on the influence of spirulina supplementation on mineral status in obese patients with hypertension. Spirulina supplementation affects the iron status of obese Caucasians with well-treated hypertension.

Dietary Tributyrin Supplementation Attenuates Insulin Resistance and Abnormal Lipid Metabolism in Suckling Piglets with Intrauterine Growth Retardation

Intrauterine growth retardation (IUGR) is associated with insulin resistance and lipid disorder. Tributyrin (TB), a pro-drug of butyrate, can attenuate dysfunctions in body metabolism. In this study, we investigated the effects of TB supplementation on insulin resistance and lipid metabolism in neonatal piglets with IUGR. Eight neonatal piglets with normal birth weight (NBW) and 16 neonatal piglets with IUGR were selected, weaned on the 7th day, and fed basic milk diets (NBW and IUGR groups) or basic milk diets supplemented with 0.1% tributyrin (IT group, IUGR piglets) until day 21 (n = 8). Relative parameters for lipid metabolism and mRNA expression were measured. Piglets with IUGR showed higher (P < 0.05) concentrations of insulin in the serum, higher (P < 0.05) HOMA-IR and total cholesterol, triglycerides (TG), non-esterified fatty acid (NEFA) in the liver, and lower (P < 0.05) enzyme activities (hepatic lipase [HL], lipoprotein lipase [LPL], total lipase [TL]) and concentration of glycogen in the liver than the NBW group. TB supplementation decreased (P < 0.05) the concentrations of insulin, HOMA-IR, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol in the serum, and the concentrations of TG and NEFA in the liver, and increased (P < 0.05) enzyme activities (HL, LPL, and TL) and concentration of glycogen in the liver of the IT group. The mRNA expression for insulin signal transduction pathway and hepatic lipogenic pathway (including transcription factors and nuclear factors) was significantly (P < 0.05) affected in the liver by IUGR, which was efficiently (P < 0.05) attenuated by diets supplemented with TB. TB supplementation has therapeutic potential for attenuating insulin resistance and abnormal lipid metabolism in IUGR piglets by increasing enzyme activities and upregulating mRNA expression, leading to an early improvement in the metabolic efficiency of IUGR piglets.

Is the serum l-arginine level during early pregnancy a predictor of pregnancy-induced hypertension?

The objective of this study was to determine the concentration of serum l-arginine in healthy pregnant women and infant cord blood and to compare them with those in patients with pregnancy-induced hypertension (PIH). The serum concentration of l-arginine in normal pregnant women at early gestation (n = 186) was determined and analyzed based on maternal factors such as the age, pre-pregnancy body mass index (BMI), smoking and alcohol habits before pregnancy. Similarly, the concentration of cord blood of the newborns (n = 142) was also analyzed. These values were compared with those in the PIH group (n = 21). The potential risk factors for PIH were also estimated. The serum concentration of l-arginine at early gestation in normal pregnant women (88.65 ± 19.96 µM) was not affected by the maternal age and BMI before pregnancy. A lower l-arginine concentration at early gestation (<70 µM) significantly elevated PIH risk [adjusted odds ratio (OR) = 4.26, 95% CI 1.29-14.50]. In addition, either women with large body mass before pregnancy (BMI>25 kg/m(2)) or primipara women also showed a significant association with PIH risk [adjusted OR = 10.55 (2.95-40.68); 5.25 (1.72-19.15), respectively]. In conclusion, a lower l-arginine concentration at early gestation, overweight before pregnancy (BMI>25 kg/m(2)) and primipara could predict to the development of PIH.

Regulation of obesity and insulin resistance by nitric oxide

Obesity is a risk factor for developing type 2 diabetes and cardiovascular disease and has quickly become a worldwide pandemic with few tangible and safe treatment options. Although it is generally accepted that the primary cause of obesity is energy imbalance, i.e., the calories consumed are greater than are utilized, understanding how caloric balance is regulated has proven a challenge. Many "distal" causes of obesity, such as the structural environment, occupation, and social influences, are exceedingly difficult to change or manipulate. Hence, molecular processes and pathways more proximal to the origins of obesity-those that directly regulate energy metabolism or caloric intake-seem to be more feasible targets for therapy. In particular, nitric oxide (NO) is emerging as a central regulator of energy metabolism and body composition. NO bioavailability is decreased in animal models of diet-induced obesity and in obese and insulin-resistant patients, and increasing NO output has remarkable effects on obesity and insulin resistance. This review discusses the role of NO in regulating adiposity and insulin sensitivity and places its modes of action into context with the known causes and consequences of metabolic disease.

An association of metabolic syndrome constellation with cellular membrane caveolae

Metabolic syndrome (MetS) is a cluster of metabolic abnormalities that can predispose an individual to a greater risk of developing type-2 diabetes and cardiovascular diseases. The cluster includes abdominal obesity, dyslipidemia, hypertension, and hyperglycemia - all of which are risk factors to public health. While searching for a link among the aforementioned malaises, clues have been focused on the cell membrane domain caveolae, wherein the MetS-associated active molecules are colocalized and interacted with to carry out designated biological activities. Caveola disarray could induce all of those individual metabolic abnormalities to be present in animal models and humans, providing a new target for therapeutic strategy in the management of MetS.

The effects of L-arginine, alone and combined with vitamin C, on mineral status in relation to its antidiabetic, anti-inflammatory, and antioxidant properties in male rats on a high-fat diet

The aim of this study was to evaluate the influence of the intake of L-arginine alone and of L-arginine with vitamin C on mineral concentration in rats fed with a high-fat diet, and to assess the lipid glucose, insulin, and total antioxidant status (TAS) and tumor necrosis factor (TNF) alpha serum levels that result. Wistar rats were assigned to groups fed with either a standard control diet (C), a diet high in fat (FD), a diet high in fat with L-arginine, or a diet high in fat with L-arginine and vitamin C. After 6 weeks, the length and weight of the rats were measured, and the animals were euthanized. The liver, spleen, kidneys, pancreas, heart, and gonads were collected, as were blood samples. The total serum cholesterol, triglyceride, fasting glucose, insulin, TAS, and TNF alpha levels were measured. The tissue calcium, magnesium, iron, zinc, and copper concentrations were determined. It was found that L-arginine supplementation diminished the effect of the modified diet on the concentration of iron in the liver and spleen and of copper in heart. At the same time, it was observed that L-arginine supplementation reduced the effect of the high-fat diet on insulin, TNF alpha, and TAS. The combination of L-arginine and vitamin C produced a similar effect on the mineral levels in the tissues as did L-arginine used alone. Moreover, positive correlations between serum insulin and iron in the liver, between TNF alpha and iron in the liver, and between TNF alpha and copper in the heart were observed. The level of TAS in serum was inversely correlated with the copper level in the heart and the iron level in the liver. We concluded that the beneficial influence of L-arginine on insulin, TAS, and TNF alpha serum level is associated with changes in the iron and copper status in rats fed with a high-fat diet. No synergistic effect of L-arginine and vitamin C in the biochemical parameters or in the mineral status in rats fed with the modified diet was observed.

Antiobesogenic role of endothelial nitric oxide synthase

The prevalence of obesity has increased remarkably in the past four decades. Because obesity can promote the development of type 2 diabetes and cardiovascular disease, understanding the mechanisms that engender weight gain and discovering safe antiobesity therapies are of critical importance. In particular, the gaseous signaling molecule, nitric oxide (NO), appears to be a central factor regulating adiposity and systemic metabolism. Obese and diabetic states are characterized by a deficit in bioavailable NO, with such decreases commonly attributed to downregulation of endothelial NO synthase (eNOS), loss of eNOS activity, or quenching of NO by its reaction with oxygen radicals. Gain-of-function studies, in which vascular-derived NO has been increased pharmacologically or genetically, reveal remarkable actions of NO on body composition and systemic metabolism. This review addresses the metabolic actions of eNOS and the potential therapeutic utility of harnessing its antiobesogenic effects.