Relationship between insulin resistance and lipid peroxidation and antioxidant vitamins in hypercholesterolemic patients

Synergistic Effect of Diet and Physical Activity on a NAFLD Cohort: Metabolomics Profile and Clinical Variable Evaluation

Together with its comorbidities, nonalcoholic fatty liver disease (NAFLD) is likely to rise further with the obesity epidemic. However, the literature's evidence shows how its progression can be reduced by the administration of calorie-restrictive dietary interventions and physical activity regimens. The liver function and the gut microbiota have been demonstrated to be closely related. With the aim of ascertaining the impact of a treatment based on the combination of diet and physical activity (versus physical activity alone), we recruited 46 NAFLD patients who were divided into two groups. As a result, we traced the connection between volatile organic compounds (VOCs) from fecal metabolomics and a set of statistically filtered clinical variables. Additionally, we identified the relative abundances of gut microbiota taxa obtained from 16S rRNA gene sequencing. Statistically significant correlations emerged between VOCs and clinical parameters, as well as between VOCs and gut microbiota taxa. In comparison with a physical activity regimen alone, we disclose how ethyl valerate and pentanoic acid butyl ester, methyl valerate, and 5-hepten-2-one, 6-methyl changed because of the positive synergistic effect exerted by the combination of the Mediterranean diet and physical activity regimens. Moreover, 5-hepten-2-one, 6-methyl positively correlated with Sanguinobacteroides, as well as the two genera Oscillospiraceae-UCG002 and Ruminococcaceae UCG010 genera.

Microalgae as a Nutraceutical Tool to Antagonize the Impairment of Redox Status Induced by SNPs: Implications on Insulin Resistance

Microalgae represent a growing innovative source of nutraceuticals such as carotenoids and phenolic compound which are naturally present within these single-celled organisms or can be induced in response to specific growth conditions. The presence of the unfavourable allelic variant in genes involved in the control of oxidative stress, due to one or more SNPs in gene encoding protein involved in the regulation of redox balance, can lead to pathological conditions such as insulin resistance, which, in turn, is directly involved in the pathogenesis of type 2 diabetes mellitus. In this review we provide an overview of the main SNPs in antioxidant genes involved in the promotion of insulin resistance with a focus on the potential role of microalgae-derived antioxidant molecules as novel nutritional tools to mitigate oxidative stress and improve insulin sensitivity.

Relationships between Skin Carotenoid Levels and Metabolic Syndrome

Carotenoids have potential antioxidant and anti-inflammatory effects; their protective roles are of particular interest in the pathogenesis of metabolic syndrome (MetS). The reflection spectroscopy method has been recently developed to noninvasively measure skin carotenoid (SC) levels, which highly correlates with serum concentration of carotenoids. The relationship between SC levels and metabolic syndrome has been investigated. We aimed to identify the differences in patient characteristics and SC levels between participants with and without MetS in a large health examination population. In addition, the relationships between SC levels and various clinical parameters related to MetS were investigated. SC levels were measured using a reflection spectroscopy. A total of 1812 Japanese participants (859 male, 953 female; mean age ± standard deviation (SD), 57.8 ± 11.0 years) comprised the study population, i.e., participants with MetS (n = 151) and those without MetS (n = 1661). Multivariate logistic regression analysis was performed to identify variables associated with MetS. Compared to controls (377.3 ± 122.8), SC indices were significantly lower in patients with MetS (340.7 ± 112.5, p = 0.0004). Multivariate models also suggested that lower SC was significantly associated with MetS after adjustment for age, sex, smoking habit, and other potential risk factors for MetS. Furthermore, male gender (p < 0.0001), smoking habit (p < 0.0001) and worse lipid profiles (i.e., serum triglyceride (r = -0.1039, p < 0.0001), high-density lipoprotein (r = 0.1259, p < 0.0001), and usage of hypolipidemic agents (p = 0.0340)) were significantly associated with lower SC levels. The current study indicated that lower SC levels were significantly associated with MetS. This study highlights the antioxidant capacity of carotenoids in patients with MetS and the clinical utility of non-invasive and cost-effective SC measurement to detect participants who are at risk of developing MetS in a large population.

Anti-aging effect of DL-β-hydroxybutyrate against hepatic cellular senescence induced by D-galactose or γ-irradiation via autophagic flux stimulation in male rats

The present study aims to shed new light on anti-aging effect of DL-β-hydroxybutyrate (βOHB) against hepatic cellular senescence induced by d-galactose or γ-irradiation. The rats divided into 6 groups. Group 1, control, group 2, exposed to γ-ray (5 GY), group 3, injected by d-galactose (150 mg/kg) daily for consecutive 6 weeks, which regarded to induce the aging, group 4, injected intraperitoneal by β-hydroxybutyrate (βOHB) (72.8 mg/kg) daily for consecutive 14 days, group 5, exposed to γ-ray then treated with βOHB daily for consecutive 14 days, group 6, injected daily with d-galactose for consecutive 6 weeks, then treated with βOHB daily at the last two weeks of d-galactose. Aspartate amino transferase (AST), alanine amino transferase (ALT), Insulin, interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) were estimated in serum. Moreover, protein expression of Microtubule-associated proteins 1A/1B light chain 3B (LC3-II/LC3-I) ratio, mechanistic target of rapamycin (mTOR), pAMPK, mRNA gene expression of 5' AMP-activated protein kinase (AMPK), Nucleoporin p62 (p62), cyclin-dependent kinase inhibitor 1(P21^CIP1), cyclin-dependent kinase inhibitor 2A (p16^INK4a) and DNA fragmentation percentage were measured in liver tissue as a biomarker of cellular senescence. The results confirmed that βOHB modulated serum level of AST, ALT, insulin, IL-6 and TNF-α, protein expression of mTOR and LC3-II/LC3-I ratio, pAMPK and p62 in liver aging model induced by d-galactose or γ-irradiation. Histopathological examination results of liver tissue indicated coincidence with those recorded by molecular biochemical inspection. Taken together, these findings suggest that βOHB may be useful in combating hepatic cellular senescence induced by d-galactose or γ-irradiation via autophagy dependent mechanisms.

[New aspects of Helicobacter pylori infection: Association with metabolic disturbances]

The review is devoted to the analysis of the literature on the possible association of Helicobacter pylori infection with type 2 diabetes mellitus, metabolic syndrome and its supposed mechanisms.

Effects of Moringa oleifera aqueous leaf extract in alloxan induced diabetic mice

OBJECTIVE

There is a lack of knowledge regarding the underlying mechanisms of the antidiabetic activity of Moringa oleifera. This study investigates the antidiabetic effect of M. oleifera and its impact on the immune tolerance.

METHODS

Alloxan-induced diabetes model for mice was used. A dose of 100 mg/kg of Moringa extract was orally administered to diabetic treated mice. Glucose and insulin levels were evaluated to calculate insulin resistance. Total antioxidant capacity (TAC), creatinine, and blood urea nitrogen (BUN) levels were measured. The relative percentage of CD44, CD69, and IFN-γ was investigated by flow cytometry.

RESULTS

In diabetic mice, insulin resistance by homeostasis model assessment of insulin resistance (HOMA-IR) was increased 4.5-fold than in the control group, and HOMA-IR was decreased 1.3-fold in the Moringa treatment group. The level of TAC was declined 1.94-fold in diabetic mice, and increased 1.67-fold in diabetic treated group. In diabetic mice, creatinine and BUN levels were significantly reduced 1.42- and 1.2-fold, respectively, in Moringa treatment mice. The relative percentage of CD44 was not changed in diabetic mice, but the relative percentage of CD69 was found to be increased. INF-γ was decreased 2.4-fold in diabetic mice and elevated in treated groups.

CONCLUSION

Moringa may ameliorate insulin resistance, increase TAC, and improve immune tolerance.

Behavior of the total antioxidant status in a group of subjects with metabolic syndrome

AIMS

Our purpose was to examine the total antioxidant status (TAS) in subjects with metabolic syndrome (MS) subdivided according to the presence or not of diabetes mellitus.

METHODS

We enrolled 106 subjects (45 women, 61 men) with MS subsequently subdivided in diabetics (14 women, 29 men) and nondiabetics (31 women, 29 men). TAS was obtained using an Assay kit which relies on the ability of plasma antioxidant substances to inhibit the oxidation of 2,2'-azino-bis(3-ethylbenzthiazoline sulfonic acid) to the radical ABTS·+.

RESULTS

In the group of MS subjects a significant decrease in TAS (p<0.05) in comparison with normal controls was evident. This difference was present between normal subjects and nondiabetic subjects with MS (p<0.001) but not between normal and diabetic subjects with MS. Examining the linear regression among TAS, age, anthropometric profile, blood pressure values and glycometabolic pattern, conflicting data were found.

CONCLUSIONS

Although we know that TAS includes several enzymatic and non enzymatic antioxidants, we retain that the difference observed in the two subgroups of subjects with MS must be looked in particular into two pathophysiological aspects regarding bilirubin and uric acid.

Branched chain amino acids are associated with muscle mass in functionally limited older adults

BACKGROUND

Metabolic profiling may provide insight into biologic mechanisms related to the maintenance of muscle and fat-free mass in functionally limited older adults. The objectives of the study were to characterize the association between thigh muscle cross-sectional area (CSA) and the fat-free mass index (FFMI; total lean mass/height(2)) with the serum metabolite profile, to further identify significant metabolites as associated with markers of insulin resistance or inflammation, and to develop a metabolite predictor set representative of muscle CSA and the FFMI in functionally limited older adults.

METHODS

Multivariable-adjusted linear regression was used on mass spectrometry-based metabolomic data to determine significant associations between serum metabolites with muscle CSA and the FFMI in 73 functionally limited (Short Physical Performance Battery ≤ 10) older adults (age range: 70-85 years). Significant metabolites were further examined for associations with markers of insulin resistance (homeostasis model assessment of insulin resistance) or inflammation (tumor necrosis factor-α and interleukin-6). Multivariable-adjusted stepwise regression was used to develop a metabolite predictor set representative of muscle CSA and the FFMI.

RESULTS

Seven branched chain amino acid-related metabolites were found to be associated with both muscle CSA and the FFMI. Separately, two metabolites were identified as insulin resistance-associated markers of the FFMI, whereas four metabolites were identified as inflammation-associated markers of either muscle CSA or the FFMI. Stepwise models identified combinations of metabolites to explain approximately 68% of the variability inherent in muscle CSA or the FFMI.

CONCLUSIONS

Collectively, we report multiple branched chain amino acids and novel inflammation-associated tryptophan metabolites as markers of muscle CSA or the FFMI in functionally limited older adults.

Flaxseed supplementation improved insulin resistance in obese glucose intolerant people: a randomized crossover design

Background

Obesity leads to an increase in inflammation and insulin resistance. This study determined antioxidant activity of flaxseed and its role in inflammation and insulin resistance in obese glucose intolerant people.

Methods

Using a randomized crossover design, nine obese glucose intolerant people consumed 40 g ground flaxseed or 40 g wheat bran daily for 12 weeks with a 4-week washout period. Plasma inflammation biomarkers (CRP, TNF-α, and IL-6), glucose, insulin, and thiobaribituric acid reactive substance (TBARS) were measured before and after of each supplementation.

Results

Flaxseed supplementation decreased TBARS (p = 0.0215) and HOMA-IR (p = 0.0382). Flaxseed or wheat bran supplementation did not change plasma inflammatory biomarkers. A positive relationship was found between TBARS and HOMA-IR (r = 0.62, p = 0.0003).

Conclusions

The results of the study weakly support that decreased insulin resistance might have been secondary to antioxidant activity of flaxseed. However, the mechanism(s) of decreased insulin resistance by flaxseed should be further determined using flaxseed lignan.

N-6 from different sources protect from metabolic alterations to obese patients: a factor analysis

First, to analyze the interactions among fatty acids (FAs) from diet, plasma and subcutaneous and visceral adipose tissue (AT), and second, the relationship among FAs from these different sources and obesity-related alterations in extreme obesity. We studied 20 extreme obese subjects. A food-frequency questionnaire was used to determine the FA intakes. Serum and AT (subcutaneous and visceral) FA concentrations were determined by gas chromatography. Cardiometabolic risk parameters were assessed. Principal factor analysis was performed to define specific FA factors in the metabolic alterations. We found important associations among diet, plasma, and AT FA and cardiometabolic parameters. In this regard, it is interesting to highlight the negative associations between plasma cholesterol and dietary n-3 FA. In the subcutaneous depot, as occurred in plasma, n-6 and polyunsaturated FAs (PUFA) were negatively associated with triacylglycerols (TGs). Factor analysis revealed TGs as the unique cardiovascular risk parameter appearing in the first factor (F1), together with n-6 (load factor = 0.94) and PUFA (0.91). Besides, n-3 from diet and plasma appeared in the third factor inversely related to cholesterol, low-density lipoprotein cholesterol (LDL-c), and insulin. In an opposite way, dietary and AT trans FAs and saturated FA (SFA) were associated to an increase of the metabolic risk. We have shown, for the first time, the importance of n-6 and PUFAs composition as protective factors against metabolic alterations in extreme obese subjects. These findings support current dietary recommendations to increase PUFA intakes and restrict saturated and trans FA intakes even in extreme obesity.

Rosiglitazone modulates fasting and post-prandial paraoxonase 1 activity in type 2 diabetic patients

1. In the present study, we have explored the effect of rosiglitazone on post-prandial paraoxonase (PON)-1, an enzyme with potent anti-oxidant properties that may protect against atherosclerosis because increased post-prandial lipaemia, although sometimes understated, is part of the diabetic dyslipidaemia. 2. A randomized, cross-over, placebo-controlled, double-blind clinical trial was performed. Participants (19 type 2 diabetic patients on oral antihyperglycaemic agents) were randomly assigned to receive either placebo or rosiglitazone 4 mg twice daily for 8 weeks. After a 6 week wash-out, the alternative treatment was implemented. Standardized 6 h oral fat-loading tests were performed after each treatment period. 3. Patients assigned to rosiglitazone had increased fasting PON-1 activity (from 331 +/- 29 to 362 +/- 32 U/L before treatment vs after treatment, respectively; P = 0.015), although the PON-1 mass did not change (68.8 +/- 21.1 vs 64.2 +/- 25.4 mg/L before treatment vs after treatment, respectively). In addition, rosiglitazone significantly decreased fasting plasma peroxides compared with placebo (162 +/- 25 vs 214 +/- 28 mmol/L, respectively; P = 0.019). The post-prandial fall in PON-1 activity, expressed as area under the curve, was attenuated by rosiglitazone (-97 +/- 14 vs-161 +/- 24 Uh/L for rosiglitazone vs placebo, respectively; P = 0.02) and the increase in PON-1 activity caused by rosiglitazone correlated with reductions in fasting plasma glucose (r = -0.42; P < 0.05), homeostatic model assessment index (r = -0.59; P < 0.01) and peroxides (r = -0.40; P = 0.07). 4. The present data indicate that rosiglitazone may convey increased protection against the oxidative modification that represents increased post-prandial lipaemia.

Insulin resistance in H pylori infection and its association with oxidative stress

AIM: To determine the insulin resistance (IR) and oxidative status in H pylori infection and to find out if there is any relationship between these parameters and insulin resistance.

METHODS: Fifty-five H pylori positive and 48 H pylori negative patients were enrolled. The homeostasis model assessment (HOMA) was used to assess insulin resistance. Serum total antioxidant capacity (TAC), total oxidant status (TOS) and oxidative stress index (OSI) were determined in all subjects.

RESULTS: The total antioxidant capacity was significantly lower in H pylori positive group than in H pylori negative group (1.36 ± 0.33 and 1.70 ± 0.50, respectively; P < 0.001), while the total oxidant status and oxidative stress index were significantly higher in H pylori positive group than in H pylori negative group (6.79 ± 3.40 and 5.08 ± 0.95, and 5.42 ± 3.40 and 3.10 ± 0.92, respectively; P < 0.001). Insulin resistance was significantly higher in H pylori positive group than in H pylori negative group (6.92 ± 3.86 and 3.61 ± 1.67, respectively; P < 0.001). Insulin resistance was found to be significantly correlated with total antioxidant capacity (r = -0.251, P < 0.05), total oxidant status (r = 0.365, P < 0.05), and oxidative stress index (r = 0.267, P < 0.05).

CONCLUSION: Insulin resistance seems to be associated with increased oxidative stress in H pylori infection. Further studies are needed to clarify the mechanisms underlying this association and elucidate the effect of adding antioxidant vitamins to H pylori eradication therapy on insulin resistance during H pylori infection.