Effects of short-term chromium supplementation on insulin sensitivity and body composition in overweight children: randomized, double-blind, placebo-controlled study

L-Phenylalanine-derived pseudopeptidic bioinspired materials: Zn(II) induced fluorescence enhancement and precise tuning of self-assembled nanostructures

The pseudopeptide, owing to its intriguing, sustainable, and easily accessible multifunctional properties, has attracted significant research interest over the years. C2-symmetric pseudopeptidic chiral bioinspired materials have been developed for their selective sensitivity to Zn(II) ions via a turn-on fluorescence under physiological conditions. Moreover, these are promising soft materials for precisely tuning their self-assembled nanostructures after incubating with Zn(II), opening avenues for exploring similar effects in various peptidomimetics.

The effects of exercise training on insulin resistance in children and adolescents with overweight or obesity: a systematic review and meta-analysis

Aim

The aim of present meta-analysis was to determine the effects of exercise training (Exe) on insulin resistance (IR) and body weight in children and adolescents with overweight or obesity.

Methods

PubMed, Web of Science, and Scopus were searched for original articles, published through October 2022 that included exercise versus control interventions on fasting glucose, insulin, HOMA-IR, and body weight outcomes in children and adolescents with overweight or obesity. Standardized mean differences (SMD) for fasting insulin, and weighted mean differences (WMD) for fasting glucose, HOMA-IR, body weight (BW), and 95% confidence intervals were determined using random effects models.

Results

Thirty-five studies comprising 1,550 children and adolescents with overweight and obesity were included in the present meta-analysis. Exercise training reduced fasting glucose (WMD=-2.52 mg/dL, p=0.001), fasting insulin (SMD=-0.77, p=0.001), HOMA-IR (WMD=-0.82, p=0.001), and BW (WMD=-1.51 kg, p=0.001), as compared to a control. Subgroup analyses showed that biological sex, intervention duration, type of exercise training, BMI percentile, and health status (with or without diagnosed condition), were sources of heterogeneity.

Conclusion

Exercise training is effective for lowering fasting glucose, fasting insulin, HOMA-IR, and BW in children and adolescents with overweight or obesity and could provide an important strategy for controlling IR and related factors. With clear evidence for the effectiveness of exercise interventions in this vulnerable population, it is important to determine effective approaches for increasing exercise training in children and adolescents with overweight or obesity.

A near-infrared Fluorescent Probe Based on Dicyanisophorone for the Detection of Zinc Ions (Zn2+) in Water and Living Cells

As one of the important metal ions, zinc ions (Zn²⁺) are widely involved in various physiological and pathological processes, and play fundamental roles in neurotransmission, cell metabolism and apoptosis. However, the convenient monitor of Zn²⁺ in environmental and biological samples remains challenging. In this study, a small molecule dicyanoisophorone-based schiff base incorporating with o-phenylenediamine was synthesized. It can rapidly combine with Zn²⁺ to emit significant near-infrared fluorescence (maximum emission wavelength: 660 nm), so it can be used as a probe to quantitatively detect Zn²⁺ in the range of 0-10 μM, with a detection limit as low as 4.8 nM, showing the probe has high sensitivity for Zn²⁺. And the probe has a fast response time to Zn²⁺ (less than 30 s) and a large Stoke-shift (179 nm). In addition, the high recovery rates in practical water samples, and the clear fluorescent images in living A549 cells were obtained, which are of great significance for the detection of Zn²⁺ in the environment and biosystem. Due to its simple operation, good selectivity and anti-interference ability, short detection time and high sensitivity, this probe has great application potential as a fast detection tool for Zn²⁺ in environmental water and biological samples.

Effectiveness of obesity interventions among South Korean children and adolescents and importance of the type of intervention component: a meta-analysis

BACKGROUND

Various interventions have been tested to prevent or treat childhood obesity in South Korea. However, the overall effect of those interventions is unclear, as very few reviews and meta-analyses were specific to Korean children and adolescents.

PURPOSE

We aimed to examine the overall effect of obesity interventions among Korean children and adolescents, while also examining differences by sex, age group, baseline weight category, intervention duration, number of intervention components, and type of intervention components.

METHODS

A meta-analysis was conducted for all intervention studies sampling Korean children and adolescents, with at least one control group and one month of follow-up, published between January 2000 and August 2020. Cohen d was calculated as an effect size for treatment effect, using the standardized difference between intervention group's body mass index (BMI) change and control group's BMI change.

RESULTS

The final sample included 19 intervention studies with 2,140 Korean children (mean age, 12.2 years). Overall, interventions were strongly favored over their controls (d=1.61; 95% confidence interval [CI], 1.12-2.09). The subgroup analysis showed that interventions with at least one physical activity component (d=2.43; 95% CI, 1.63-3.24) were significantly better than those that did not include physical activity (d=0.02; 95% CI, -0.26 to 0.31).

CONCLUSION

Type of intervention component appeared important, though no differential association was observed by sex, age, baseline weight category, intervention duration, and number of intervention components. Korean and non-Korean interventions may be substantively different. Additional studies are needed to understand why and how Korean interventions differ from non-Korean interventions.

Chromium picolinate balances the metabolic and clinical markers in nonalcoholic fatty liver disease: a randomized, double-blind, placebo-controlled trial

OBJECTIVE

Nonalcoholic fatty liver disease (NAFLD) is a complicated disease and is considered as a severe global health problem affecting 30% of adults worldwide. The present study aimed to evaluate changes in oxidative stress, adipokines, liver enzyme, and body composition following treatment with chromium picolinate (CrPic) among patients with NAFLD.

PARTICIPANTS AND METHODS

The current randomized, double-blind, placebo-controlled study was conducted on 46 NAFLD patients with the age range of 20-65 years. Patients were randomly classified into two groups, receiving either 400 µg CrPic tablets in two divided doses of 200 µg (23 patients) or placebo (23 patients) daily for 12 weeks. The participants' body composition and biochemical parameters were evaluated at the baseline and after 12 weeks.

RESULTS

Serum levels of liver enzymes reduced significantly only in the CrPic group (P < 0.05 for all), but not between the groups after the intervention. Besides, there were significant differences between the study groups regarding body weight and body fat mass, total antioxidant capacity, superoxide dismutase, malondialdehyde, leptin, and adiponectin post-intervention (P = 0.017, P = 0.032, P = 0.003, P = 0.023, P = 0.012, P = 0.003, and P = 0.042, respectively). However, glutathione peroxidase and resistin levels did not differ significantly between groups (P = 0.127 and P = 0.688, respectively).

DISCUSSION AND CONCLUSION

This study showed that consuming 400 µg/day of CrPic for 12 weeks in patients with NAFLD causes a significant change in leptin, adiponectin, oxidative stress (expect glutathione peroxidase), and body weight, compared to baseline. Nevertheless, it does not affect liver enzymes. Therefore, the CrPic supplementation may improve adipokines, some anthropometric indices, and oxidative stress in patients with NAFLD.

A Highly Selective Turn-On Fluorescent Probe for the Detection of Zinc

A novel turn-on fluorescence probe L has been designed that exhibits high selectivity and sensitivity with a detection limit of 9.53 × 10⁻⁸ mol/L for the quantification of Zn²⁺. ¹H-NMR spectroscopy and single crystal X-ray diffraction analysis revealed the unsymmetrical nature of the structure of the Schiff base probe L. An emission titration experiment in the presence of different molar fractions of Zn²⁺ was used to perform a Job’s plot analysis. The results showed that the stoichiometric ratio of the complex formed by L and Zn²⁺ was 1:1. Moreover, the molecular structure of the mononuclear Cu complex reveals one ligand L coordinates with one Cu atom in the asymmetric unit. On adding CuCl₂ to the ZnCl₂/L system, a Cu-Zn complex was formed and a strong quenching behavior was observed, which inferred that the Cu²⁺ displaced Zn²⁺ to coordinate with the imine nitrogen atoms and hydroxyl oxygen atoms of probe L.

Excessive caloric intake acutely causes oxidative stress, GLUT4 carbonylation, and insulin resistance in healthy men

Obesity-linked insulin resistance greatly increases the risk for type 2 diabetes, hypertension, dyslipidemia, and non-alcoholic fatty liver disease, together known as the metabolic or insulin resistance syndrome. How obesity promotes insulin resistance remains incompletely understood. Plasma concentrations of free fatty acids and proinflammatory cytokines, endoplasmic reticulum ( ER) stress, and oxidative stress are all elevated in obesity and have been shown to induce insulin resistance. However, they may be late events that only develop after chronic excessive nutrient intake. The nature of the initial event that produces insulin resistance at the beginning of excess caloric intake and weight gain remains unknown. We show that feeding healthy men with ~6000 kcal/day of the common U.S. diet [~50% carbohydrate (CHO), ~ 35% fat, and ~15% protein] for 1 week produced a rapid weight gain of 3.5 kg and the rapid onset (after 2 to 3 days) of systemic and adipose tissue insulin resistance and oxidative stress but no inflammatory or ER stress. In adipose tissue, the oxidative stress resulted in extensive oxidation and carbonylation of numerous proteins, including carbonylation of GLUT4 near the glucose transport channel, which likely resulted in loss of GLUT4 activity. These results suggest that the initial event caused by overnutrition may be oxidative stress, which produces insulin resistance, at least in part, via carbonylation and oxidation-induced inactivation of GLUT4.

A Dietary Supplement Containing Cinnamon, Chromium and Carnosine Decreases Fasting Plasma Glucose and Increases Lean Mass in Overweight or Obese Pre-Diabetic Subjects: A Randomized, Placebo-Controlled Trial

BACKGROUND

Preventing or slowing the progression of prediabetes to diabetes is a major therapeutic issue.

OBJECTIVES

Our aim was to evaluate the effects of 4-month treatment with a dietary supplement containing cinnamon, chromium and carnosine in moderately obese or overweight pre-diabetic subjects, the primary outcome being change in fasting plasma glucose (FPG) level. Other parameters of plasma glucose homeostasis, lipid profile, adiposity and inflammatory markers were also assessed.

METHODS

In a randomized, double-blind, placebo-controlled study, 62 subjects with a FPG level ranging from 5.55 to 7 mmol/L and a body mass index ≥ 25 kg/m(2), unwilling to change their dietary and physical activity habits, were allocated to receive a 4-month treatment with either 1.2 g/day of the dietary supplement or placebo. Patients were followed up until 6 months post-randomization.

RESULTS

Four-month treatment with the dietary supplement decreased FPG compared to placebo (-0.24 ± 0.50 vs +0.12 ± 0.59 mmol/L, respectively, p = 0.02), without detectable significant changes in HbA1c. Insulin sensitivity markers, plasma insulin, plasma lipids and inflammatory markers did not differ between the treatment groups. Although there were no significant differences in changes in body weight and energy or macronutrient intakes between the two groups, fat-free mass (%) increased with the dietary supplement compared to placebo (p = 0.02). Subjects with a higher FPG level and a milder inflammatory state at baseline benefited most from the dietary supplement.

CONCLUSIONS

Four-month treatment with a dietary supplement containing cinnamon, chromium and carnosine decreased FPG and increased fat-free mass in overweight or obese pre-diabetic subjects. These beneficial effects might open up new avenues in the prevention of diabetes.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01530685.

Mitochondrial dysfunction and insulin resistance: an update

Mitochondrial dysfunction has been implicated in the development of insulin resistance (IR); however, a large variety of association and intervention studies as well as genetic manipulations in rodents have reported contrasting results. Indeed, even 39 years after the first publication describing a relationship between IR and diminished mitochondrial function, it is still unclear whether a direct relationship exists, and more importantly if changes in mitochondrial capacity are a cause or consequence of IR. This review will take a journey through the past and summarise the debate about the occurrence of mitochondrial dysfunction and its possible role in causing decreased insulin action in obesity and type 2 diabetes. Evidence is presented from studies in various human populations, as well as rodents with genetic manipulations of pathways known to affect mitochondrial function and insulin action. Finally, we have discussed whether mitochondria are a potential target for the treatment of IR.