Is chromium(III) pharmacologically relevant? An update focused on studies with diabetic rodent models

A decade ago, the author assessed the status of chromium as the trivalent ion as an essential element and as a therapeutic agent based on rodent studies for this journal. The current review was undertaken to update considerations regarding the status of chromium, focusing on studies of Cr supplementation of diabetic rodent models over the last decade. Cr can no longer be considered an essential trace element for humans. Observed effects of Cr on rodent models of insulin resistance and diabetes are best interpreted in terms of a pharmacological role for Cr. The review of studies on the effects of Cr on rat models of diabetes is updated, and the results continue to suggest Cr increases insulin sensitivity in peripheral tissues of the rodent models. The lack of effects in human studies may stem from humans receiving a comparably smaller dose than the rodent models. However, given the different responses to Cr in the rodent models, humans could potentially have different responses to Cr. Recent studies primary utilizing rodents suggest two potential complementary but also contradictory modes of action for Cr(III) at a molecular level.

Is chromium(III) supplementation beneficial for dietary rodent models of prediabetes?

Chromium as the trivalent ion is believed to pharmaceutically active, increasing insulin sensitivity in high doses in genetic rodent models of diabetes. However, contradictory results have been obtained chemical rodent models of diabetes. The current review analyses the effects of dietary Cr supplementation of rodent models of prediabetes, where the condition is administered using a high-fat or high-sugar diet. Rat model studies display a range of quality, with studies utilizing basal diets of known Cr content suggesting Cr beneficially affects insulin sensitivity. Mouse model studies display too much heterogeneity in results for any firm conclusions to be drawn. Comparison of these results with those of clinical trials suggest that the effective dose of Cr may be proportionally lower for rodents than humans, if one exists for humans.

Special features on insulin resistance, metabolic syndrome and vascular complications in hypopituitary patients

Pituitary hormone deficiency, hypopituitarism, is a dysfunction resulting from numerous etiologies, which can be complete or partial, and is therefore heterogeneous. This heterogeneity makes it difficult to interpret the results of scientific studies with these patients.Adequate treatment of etiologies and up-to-date hormone replacement have improved morbidity and mortality rates in patients with hypopituitarism. As GH replacement is not performed in a reasonable proportion of patients, especially in some countries, it is essential to understand the known consequences of GH replacement in each subgroup of patients with this heterogeneous dysfunction.In this review on hypopituitarism, we will address some particularities regarding insulin resistance, which is no longer common in these patients with hormone replacement therapy based on current guidelines, metabolic syndrome and its relationship with changes in BMI and body composition, and to vascular complications that need to be prevented taking into account the individual characteristics of each case to reduce mortality rates in these patients.

Upregulation of Oxidative Phosphorylation Genes in Cumulus Cells of The Polycystic Ovary Syndrome Patients with or without Insulin Resistance

OBJECTIVE

The relationship between oxidative stress (OS), insulin resistance (IR), and polycystic ovary syndrome (PCOS) is an important medical issue in human reproduction. Some of the oxidative phosphorylation (OXPHOS) genes have been previously studied in granulosa and muscle cells of PCOS patients. Cumulus cells (CCs) remain close to the oocyte even after ovulation. This research has been designed to compare the expression of OXPHOS genes in CCs of PCOS, with or without insulin resistance.

MATERIALS AND METHODS

In this experimental study, patients were included in PCOS insulin-resistant, PCOS insulinsensitive (IS), and control (fertile women with male infertility history) groups. The expression of NCF2, TXNIP, UCP2, NDUFB6, ATP5H, COX7C, NDUFA3, SDHA, and SDHB was studied by real-time polymerase chain reaction (PCR), and normalization was performed considering HPRT1 and CYC1 as reference genes. One-way ANOVA and Tukey test were used for data analysis.

RESULTS

The results showed that the expression of NCF2, TXNIP, UCP2, and ATP5H was significantly higher in the IR group than IS and control groups (P<0.01). NDUFB6 showed the highest expression in the IS group, which was significantly different from other groups (P<0.01). The other genes of interest, except COX7C, were observed with the most transcriptional levels in the IS group, although there was no significant difference for those genes.

CONCLUSION

Altered expression of genes involved in mitochondrial function compared to the control group in CCs of both IR and IS categories of the PCOS patients suggests that alteration in OXPHOS genes can contribute to the pathophysiology of PCOS.

Molecular effects of Vitamin-D and PUFAs metabolism in skeletal muscle combating Type-II diabetes mellitus

Multiple post-receptor intracellular alterations such as impaired glucose transfer, glucose phosphorylation, decreased glucose oxidation, and glycogen production contribute to insulin resistance (IR) in skeletal muscle, manifested by diminished insulin-stimulated glucose uptake. Type-2 diabetes mellites (T2DM) has caused by IR, which is also seen in obese patients and those with metabolic syndrome. The Vitamin-D receptor (VDR) and poly unsaturated fatty acids (PUFAs) roles in skeletal muscle growth, shapes, and function for combating type-2 diabetes have been clarified throughout this research. VDR and PUFAs appears to show a variety of effects on skeletal muscle, in addition it shows a promising role on bone and mineral homeostasis. Individuals having T2DM are reported to suffer from severe muscular weakness and alterations in shape of the muscle. Several studies have investigated the effect on VDR on muscular strength and mass, which leads to Vitamin-D deficiency (VDD) in individuals, in which most commonly seen in elderly. VDR has been shown to affect skeletal cellular proliferation, intracellular calcium handling, as well as genomic activity in a variety of different ways such as muscle metabolism, insulin sensitivity, which is the major characteristic pathogenesis for IR in combating T2DM. The identified VDR gene polymorphisms are ApaI, TaqI, FokI, and BsmI that are associated with T2DM. This review collates informations on the mechanisms by which VDR activation takes place in skeletal muscles. Despite the significant breakthroughs made in recent decades, various studies show that IR affects VDR and PUFAs metabolism in skeletal muscle. Therefore, this review collates the data to show the role of VDR and PUFAs in the skeletal muscles to combat T2DM.

Impaired Fibroblast Growth Factor 21 (FGF21) Associated with Visceral Adiposity Leads to Insulin Resistance: The Core Defect in Diabetes Mellitus

The Central nervous system (CNS) is the prime regulator of signaling pathways whose function includes regulation of food intake (consumption), energy expenditure, and other metabolic responses like glycolysis, gluconeogenesis, fatty acid oxidation, and thermogenesis that have been implicated in chronic inflammatory disorders. Type 2 diabetes mellitus (T2DM) and obesity are two metabolic disorders that are linked together and have become an epidemic worldwide, thus raising significant public health concerns. Fibroblast growth factor 21 (FGF21) is an endocrine hormone with pleiotropic metabolic effects that increase insulin sensitivity and energy expenditure by elevating thermogenesis in brown or beige adipocytes, thus reducing body weight and sugar intake. In contrast, during starvation conditions, FGF21 induces its expression in the liver to initiate glucose homeostasis. Insulin resistance is one of the main anomalies caused by impaired FGF21 signaling, which also causes abnormal regulation of other signaling pathways. Tumor necrosis factor alpha (TNF-α), the cytokine released by adipocytes and inflammatory cells in response to chronic inflammation, is regarded major factor that reduces the expression of FGF21 and modulates underlying insulin resistance that causes imbalanced glucose homeostasis. This review aims to shed light on the mechanisms underlying the development of insulin resistance in obese individuals as well as the fundamental flaw in type 2 diabetes, which is malfunctioning obese adipose tissue.

Liver ChREBP deficiency inhibits fructose-induced insulin resistance in pregnant mice and female offspring

High fructose intake during pregnancy increases insulin resistance (IR) and gestational diabetes mellitus (GDM) risk. IR during pregnancy primarily results from elevated hormone levels. We aim to determine the role of liver carbohydrate response element binding protein (ChREBP) in insulin sensitivity and lipid metabolism in pregnant mice and their offspring. Pregnant C57BL/6J wild-type mice and hepatocyte-specific ChREBP-deficient mice were fed with a high-fructose diet (HFrD) or normal chow diet (NC) pre-delivery. We found that the combination of HFrD with pregnancy excessively activates hepatic ChREBP, stimulating progesterone synthesis by increasing MTTP expression, which exacerbates IR. Increased progesterone levels upregulated hepatic ChREBP via the progesterone-PPARγ axis. Placental progesterone activated the progesterone-ChREBP loop in female offspring, contributing to IR and lipid accumulation. In normal dietary conditions, hepatic ChREBP modestly affected progesterone production and influenced IR during pregnancy. Our findings reveal the role of hepatic ChREBP in regulating insulin sensitivity and lipid homeostasis in both pregnant mice consuming an HFrD and female offspring, and suggest it as a potential target for managing gestational metabolic disorders, including GDM.

Non-Insulin-Based Indices of Insulin Resistance for Predicting Incident Albuminuria: A Nationwide Population-Based Study

Background

Studies have shown that incident albuminuria is associated with insulin resistance (IR); however, an IR marker that best predicts the prevalence of albuminuria has not yet been established. This study explored the association between IR and incident albuminuria using various IR indices, including the homeostasis model assessment of IR (HOMA-IR), metabolic score for IR (METS-IR), and triglyceride-glucose (TyG) index, and compared their predictive abilities for the prevalence of albuminuria.

Methods

A total of 4,982 Korean adults from the 2019 Korea National Health and Nutritional Examination Survey were analyzed. The odds of albuminuria were determined using the quartiles of the IR indices. Receiver operating characteristic (ROC) curves were used to calculate the area under the ROC curve and predictability. The cutoff values for albuminuria detection were also computed.

Results

An increase in the quartiles of all three IR indices was associated with incident albuminuria, even after full adjustment for covariates (HOMA-IR: odds ratio [OR], 1.906; 95% confidence interval [CI], 1.311-2.772; P=0.006; METS-IR: OR, 2.236; 95% CI, 1.353-3.694; P=0.002; TyG index: OR, 1.757; 95% CI, 1.213-2.544; P=0.003). The area under the ROC curve for incident albuminuria based on the HOMA-IR, METS-IR, and TyG indices was 0.594 (95% CI, 0.568-0.619), 0.633 (95% CI, 0.607-0.659), and 0.631 (95% CI, 0.606-0.656), respectively. The optimal cutoff values for predicting albuminuria were 2.38, 35.38, and 8.72 for the HOMA-IR, METS-IR, and TyG indices, respectively.

Conclusion

The METS-IR and TyG indices outperformed HOMA-IR in predicting incident albuminuria.

Shared genetic architecture between periodontal disease and type 2 diabetes: a large scale genome-wide cross-trait analysis

PURPOSE

To investigate the relationship between abnormal glucose metabolism, type 2 diabetes (T2D), and periodontal disease (PER) independent of Body Mass Index (BMI), we employed a genome-wide cross-trait approach to clarify the association.

METHODS

Our study utilized the most extensive genome-wide association studies conducted for populations of European ancestry, including PER, T2D, fasting glucose, fasting insulin, 2-hour glucose after an oral glucose challenge, HOMA-β, HOMA-IR (unadjusted or adjusted for BMI) and HbA1c.

RESULTS

With this approach, we were able to identify pleiotropic loci, establish expression-trait associations, and quantify global and local genetic correlations. There was a significant positive global genetic correlation between T2D (rg = 0.261, p = 2.65 × 10-13), HbA1c (rg = 0.182, p = 4.14 × 10-6) and PER, as well as for T2D independent of BMI (rg = 0.158, p = 2.34 × 10-6). A significant local genetic correlation was also observed between PER and glycemic traits or T2D. We also identified 62 independent pleiotropic loci that impact both PER and glycemic traits, including T2D. Nine significant pathways were identified between the shared genes between T2D, glycemic traits and PER. Genetically liability of HOMA-βadjBMI was causally associated with the risk of PER.

CONCLUSION

Our research has revealed a genetic link between T2D, glycemic traits, and PER that is influenced by biological pleiotropy. Notably, some of these links are not related to BMI. Our research highlights an underlying link between patients with T2D and PER, regardless of their BMI.

Low Muscle Strength as Risk Factor for Non-Alcoholic Fatty Liver Disease in Different Metabolic Conditions

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) recently became a leading liver disease that threatens health worldwide. Low muscle strength, obesity, insulin resistance, and metabolic syndrome are recognized key factors for NAFLD. However, the impact of low muscle strength itself in different metabolic conditions has not been widely studied.

METHODS

A cross-sectional analysis was performed of a sample of 5,427 participants from the 2019 Korea National Health and Nutrition Examination Survey. Relative handgrip strength (rHGS, defined as handgrip strength/body mass index) was used to assess muscle strength. The cut-off values for a low rHGS were 1.405 for men and 0.850 for women. NAFLD was diagnosed if the Hepatic Steatosis Index was >36. Participants were stratified according to insulin resistance, metabolic syndrome, and central obesity for the subgroup analyses.

RESULTS

Complex sample multivariate logistic regression analysis revealed a significant association between low muscle strength and NAFLD after the adjustment for other confounders (odds ratio [OR], 1.92; P<0.001). In the insulin resistance, metabolic syndrome, and central obesity subgroups, a significant association between low muscle strength and NAFLD remained (OR, 1.66-4.19 depending on subgroup; all P<0.05), whereas it did not in the no central obesity group.

CONCLUSION

This study demonstrated that low muscle strength is correlated with a risk of NAFLD. This relationship was independent of insulin resistance and metabolic syndrome but was dependent on the presence of central obesity.

Brain insulin resistance and Alzheimer's disease: a systematic review

The disability of cells to react to insulin, causing glucose intolerance and hyperglycemia, is referred to as insulin resistance. This clinical condition, which has been well-researched in organs such as adipose tissue, muscle, and liver, has been linked to neurodegenerative diseases like Alzheimer's disease (AD) when it occurs in the brain.

Objective

The authors aimed to gather data from the current literature on brain insulin resistance (BIR) and its likely repercussions on neurodegenerative disorders, more specifically AD, through a systematic review.

Methods

A comprehensive search was conducted in multiple medical databases, including the Cochrane Central Register of Controlled Trials, EMBASE, Medical Literature Analysis and Retrieval System Online (Medline), and PubMed®, employing the descriptors: "insulin resistance", "brain insulin resistance", "Alzheimer's disease", "neurodegeneration", and "cognition". The authors focused their search on English-language studies published between 2000 and 2023 that investigated the influence of BIR on neurodegenerative disorders or offered insights into BIR's underlying mechanisms. Seventeen studies that met the inclusion criteria were selected.

Results

The results indicate that BIR is a phenomenon observed in a variety of neurodegenerative disorders, including AD. Studies suggest that impaired glucose utilization and uptake, reduced adenosine triphosphate (ATP) production, and synaptic plasticity changes caused by BIR are linked to cognitive problems. However, conflicting results were observed regarding the association between AD and BIR, with some studies suggesting no association.

Conclusion

Based on the evaluated studies, it can be concluded that the association between AD and BIR remains inconclusive, and additional research is needed to elucidate this relationship.

A Structure-function Analysis of Hepatocyte Arginase 2 Reveals Mitochondrial Ureahydrolysis as a Determinant of Glucose Oxidation

BACKGROUND & AIMS

Restoring hepatic and peripheral insulin sensitivity is critical to prevent or reverse metabolic syndrome and type 2 diabetes. Glucose homeostasis comprises in part the complex regulation of hepatic glucose production and insulin-mediated glucose uptake and oxidation in peripheral tissues. We previously identified hepatocyte arginase 2 (Arg2) as an inducible ureahydrolase that improves glucose homeostasis and enhances glucose oxidation in multiple obese, insulin-resistant models. We therefore examined structure-function determinants through which hepatocyte Arg2 governs systemic insulin action and glucose oxidation.

METHODS

To do this, we generated mice expressing wild-type murine Arg2, enzymatically inactive Arg2 (Arg2H160F) and Arg2 lacking its putative mitochondrial targeting sequence (Arg2Δ1-22). We expressed these hepatocyte-specific constructs in obese, diabetic (db/db) mice and performed genetic complementation analyses in hepatocyte-specific Arg2-deficent (Arg2LKO) mice.

RESULTS

We show that Arg2 attenuates hepatic steatosis, independent of mitochondrial localization or ureahydrolase activity, and that enzymatic arginase activity is dispensable for Arg2 to augment total body energy expenditure. In contrast, mitochondrial localization and ureahydrolase activity were required for Arg2-mediated reductions in fasting glucose and insulin resistance indices. Mechanistically, Arg2Δ1-22 and Arg2H160F failed to suppress glucose appearance during hyperinsulinemic-euglycemic clamping. Quantification of heavy-isotope-labeled glucose oxidation further revealed that mistargeting or ablating Arg2 enzymatic function abrogates Arg2-induced peripheral glucose oxidation.

CONCLUSION

We conclude that the metabolic effects of Arg2 extend beyond its enzymatic activity, yet hepatocyte mitochondrial ureahydrolysis drives hepatic and peripheral oxidative metabolism. The data define a structure-based mechanism mediating hepatocyte Arg2 function and nominate hepatocyte mitochondrial ureahydrolysis as a key determinant of glucose oxidative capacity in mammals.

Determinants of Bone Mineral Density in Iranian Women with Polycystic Ovary Syndrome

Background

Whether the endocrine aberrations caused by polycystic ovary syndrome (PCOS) might influence bone density in women of reproductive age is controversial.

Objectives

The present study aimed to compare PCOS women to a control group matched in terms of age and body mass index (BMI) regarding bone indices and to clarify the potential relationship between their hormonal changes and bone density.

Methods

This case-control study consisted of 61 PCOS patients, and 35 women with normal ovulatory function served as controls. Bone parameters, including bone mineral content (BMC) and bone mineral density (BMD) in addition to T- and Z-scores, were measured at the lumbar vertebrae, neck of the left femur, hip, and distal part of the radial bone, using dual-energy X-ray absorptiometry. Blood samples were taken to be tested for biochemical parameters and serum concentrations of insulin, osteocalcin, parathyroid hormone (PTH), vitamin D, follicle-stimulating hormone (FSH), luteinizing hormone (LH), total testosterone, dehydroepiandrosterone sulfate (DHEAS), and estradiol were measured. Insulin resistance was evaluated through the homeostatic model assessment of insulin resistance (HOMA-IR).

Results

The results revealed greater levels of HOMA-IR and total testosterone in PCOS women than in controls. Nevertheless, the two groups were comparable in terms of bone parameters. In the control group, BMI was the only determinant of bone density at most of the skeletal sites. Nonetheless, BMI and HOMA-IR were independently and positively associated with bone indices at the femoral neck (FN) and total hip in the PCOS group. Parathyroid hormone and vitamin D concentrations were not different in the two groups. However, phosphate levels were higher in PCOS patients (P = 0.025). Osteocalcin was inversely correlated to BMI, and both groups had a negative correlation between DHEAS and PTH. Serum phosphate was inversely and independently associated with estrogen in the PCOS group (r = -0.377, P = 0.004).

Conclusions

Body mass index and HOMA-IR were independent and positive determinants of FN and total hip bone density in the PCOS subjects. Nonetheless, in the non-PCOS women, BMI was the only independent determinant of bone density at most of the skeletal sites. Additionally, osteocalcin was inversely correlated with BMI in both groups.

Reinstating acute-phase insulin release among sedentary adults at high risk for type 2 diabetes with Yoga and Walking based lifestyle modification

BACKGROUND

We compared the impact of 2 lifestyle modifying physical activities, yoga (YBLM) or walking (WBLM) on impaired beta cell function (IBF) or insulin resistance (IR) in restoring acute phase insulin release (APIR) among prediabetes at high risk for type 2 diabetes (HRDM).

METHOD

Male and female adults (N = 42, 38.1 ± 4.8 years) with abdominal obesity (Male:103 ± 8.1 cm) Female: 92 ± 11.1 cm), randomized into YBLM (n = 20) and WBLM (n = 22), were monitored for the practice of the intervention, 45 min a day/5 days a week for 12 weeks. Blood sample was collected at 0th minute to estimate the level of Fasting Blood Glucose (FBG), Sr. Insulin and lipid profile and at 10th minute (APIR). IBF, IR and sensitivity (IS) reading were checked in HOMA-2 calculator.

RESULT

Wilcoxon sign rank t-test denoted an improved APIR among the subjects with IBF (p = 0.008) and not among the subjects with IR (p = 0.332). However, regression analysis yielded an improved APIR among subjects with IBF (F(1,10) = 7.816, p = 0.002) with the management of body weight and lipid profile and IR (F(1,13) = 17.003, p = 0.001) being found influenced with selected lipid components. In all, during the post assessment period, an impressive boost in APIR was manifested among people shifted to Normoglycemia (n = 14, 35.9%).

CONCLUSION

Intriguingly, we postulate the potential role of YBLM over WBLM in the management of lipid profile and body weight on accelerating APIR either through improved Beta cell compensation or by sensitizing skeletal muscles regulating IR, helping improve glucose tolerance resulting in either remission or management of prediabetes.

Triglyceride-glucose index and cervical vascular function: outpatient-based cohort study

OBJECTIVES

The purpose of this study was to investigate the correlation between triglyceride-glucose (TyG) index and cervical vascular function parameters in the general population without cerebrovascular disease.

MATERIALS AND METHODS

This was a cross-sectional study that recruited a total of 1996 participants without cerebrovascular disease. TyG index was calculated based on fasting triglycerides and glucose. All patients were divided into two groups based on the median TyG index: the high TyG group and the low TyG group. The differences in basic clinical characteristics and neck vascular function parameters between the two groups of participants were compared, and then the correlation between TyG index and neck vascular function parameters was investigated.

RESULTS

Participants with a high TyG index had lower systolic, diastolic, and mean flow velocities in the basilar, vertebral, and internal carotid arteries compared with those with a low TyG index. Participants with a high TyG index had higher pulsatility index in the left vertebral artery and right internal carotid artery, but this difference was not observed in the basilar artery. In addition, TyG index was significantly negatively correlated with systolic, diastolic, and mean flow velocities in the basilar, vertebral, and internal carotid arteries, and the correlation remained after adjusting for confounding factors.

CONCLUSION

In the general population, there was a well-defined correlation between TyG index and cervical vascular function parameters, and increased TyG index was independently associated with reduced cervical vascular blood flow velocity.

Insulin resistance drives cognitive impairment in hypertensive pre-diabetic frail elders: the CENTENNIAL study

AIMS

Pre-diabetes is a condition that confers an increased cardiovascular risk. Frailty is very common in hypertensive patients, and insulin resistance has been linked to frailty in older adults with diabetes. On these grounds, our aim was to evaluate the association between insulin resistance and cognitive impairment in hypertensive and pre-diabetic and frail older adults.

METHODS AND RESULTS

We studied consecutive pre-diabetic and hypertensive elders with frailty presenting at the Avellino local health authority of the Italian Ministry of Health (ASL AV) from March 2021 to March 2022. All of them fulfilled the following inclusion criteria: a previous diagnosis of hypertension with no clinical or laboratory evidence of secondary causes, a confirmed diagnosis of pre-diabetes, age >65 years, Montreal Cognitive Assessment (MoCA) Score <26, and frailty. We enrolled 178 frail patients, of which 141 successfully completed the study. We observed a strong inverse correlation (r = -0.807; P < 0.001) between MoCA Score and Homeostatic Model Assessment for Insulin Resistance (HOMA-IR). The results were confirmed by a linear regression analysis using MoCA Score as dependent variable, after adjusting for several potential confounders.

CONCLUSION

Taken together, our data highlight for the first time the association between insulin resistance and global cognitive function in frail elders with hypertension and pre-diabetes.

Protective Effect of Tertiary Butylhydroquinone against Obesity-induced Skeletal Muscle Pathology in Post-weaning High Fat Diet Fed Rats

BACKGROUND

Obesity deleteriously affects skeletal muscle functionality starting from infancy to adulthood, leading to dysfunctional skeletal muscle.

OBJECTIVES

This study, therefore, evaluated the protective action of tert-butylhydroquinone (tBHQ) against obesity-induced skeletal muscle pathology in high-fat diet (HFD) fed rats.

METHODS

Twenty post-weaning male albino rats were randomized into four groups of five rats each as: Group 1 (control), Group 2 (HFD), Group 3 (orlistat) and Group 4 (tBHQ). Group one received rat pellets for 12 weeks, while groups 2 to 4 received HFD for 12 weeks. At the end of week 8, obesity was confirmed with Lee Obesity Index and body mass index values of ≥ 303 and ≥ 0.68 gcm2, respectively. Group 3 was given oral administration of orlistat (10 mg/kg, once daily), while group 4 was given oral administration of tBHQ (25 mg/kg, once daily). Administration of orlistat and tBHQ commenced from week 9 to the end of the experiment.

RESULTS

Chronic exposure of post-weaning rats to HFD led to their development of the metabolic syndrome phenotypes in adulthood, characterized by obesity, hyperglycemia, dyslipidaemia, hyperinsulinaemia, insulin resistance as well as induction of oxidative stress and alteration of skeletal muscle markers, which were mitigated following supplementation with orlistat and tBHQ.

CONCLUSION

The study showed the anti-obesity potentials of tBHQ and its protective action against HFD obesity-induced skeletal muscular pathology.

The acute effects of a DASH diet and whole food, plant-based diet on insulin requirements and related cardiometabolic markers in individuals with insulin-treated type 2 diabetes

AIMS

There is limited research regarding insulin dosing changes following adoption of plant-based diets. We conducted a nonrandomized crossover trial utilizing two plant-based diets (Dietary Approaches to Stop Hypertension, or DASH, and Whole Food, Plant-Based, or WFPB) to assess acute changes in insulin requirements and associated markers among individuals with insulin-treated type 2 diabetes.

METHODS

Participants (n = 15) enrolled in a 4-week trial with sequential, one-week phases: Baseline, DASH 1, WFPB, and DASH 2. Each diet was ad libitum and meals were provided.

RESULTS

Compared to baseline, daily insulin usage was 24%, 39%, and 30% lower after DASH 1, WFPB, and DASH 2 weeks respectively (all p < 0.01). Insulin resistance (HOMA-IR) was 49% lower (p < 0.01) and the insulin sensitivity index was 38% higher (p < 0.01) at the end of the WFPB week before regressing toward baseline during DASH 2. Total, LDL, and HDL cholesterol, leptin, urinary glucose, and hsCRP decreased to a nadir at the end of the WFPB week before increasing during DASH 2.

CONCLUSIONS

Adopting a DASH or WFPB diet can result in significant, rapid changes in insulin requirements, insulin sensitivity, and related markers among individuals with insulin-treated type 2 diabetes, with larger dietary changes producing larger benefits.

The Effect of Training Type on The Signaling P athway of Ceramide-Dependent Insulin Resistance in The Flexor Hallucis Longus Muscle of Streptozotocin-Induced Diabetic Rats

OBJECTIVE

This study aimed to compare the effect of different physical training on the mechanism of ceramidedependent insulin resistance in the flexor hallucis longus (FHL) muscle of diabetic rats.

MATERIALS AND METHODS

In this experimental study, 7 healthy as a healthy control (HC) group, and 21 diabetics (55 mg/ kg Streptozotocin) Wistar rats (200-220 g; 8-10 weeks old) divided into the diabetic control (DC), moderate continuous training (MCT), and moderate intensity interval training (MIIT) groups. Both MCT (55-70% of maximal oxygen uptake (VO2max), and MIIT (85% VO2max) groups trained for 10-25 minutes at a speed of 10-20 m/minutes. The changes in the expression of blood glucose, insulin, insulin resistance, lipid profile and total ceramide were measured as well as ceramide synthase-1, Glucose transporter type 4 (GLUT4), Protein kinase B known as Akt, phosphorylated protein kinase B known as pAkt, protein kinase C (PKC), and tumour necrosis factor α (TNFα).

RESULTS

Blood glucose, triglyceride (TG) and ceramide synthase-1 (CS1) expression levels in the MCT group decreased in comparison with the DC group. FHL protein expression of GLUT4 in the MCT group was higher than the DC group. FHL expression of GLUT4, pAKT, AKT/pAKT, PKC, CS1 and total ceramide in the MIIT group were higher than the DC group. Cholesterol, low-density lipoprotein (LDL), TG, and TNF-α protein expression in the MIIT group were lower than the DC group. GLUT4, PKC, pAKT, AKT/pAKT in the MIIT group were higher, and total ceramide and TNF-α were lower in the MIIT group than the MCT group.

CONCLUSION

It seems that both training plan MIIT and MCT have favorable effects on the metabolism of glucose, insulin, lipids, and the decrease of TNFα level in the diabetes, but in connection with the improvement of the ceramides mechanism, it seems that the MIIT training plan is more optimal than MCT training plan.

12-week combined strength and endurance exercise attenuates CD8+ T-cell differentiation and affects the kynurenine pathway in the elderly: a randomized controlled trial

BACKGROUND

Age-related accumulation of highly differentiated CD8⁺ effector memory re-expressing CD45RA (EMRA) T-cells and disruption of the kynurenine (KYN) pathway are associated with chronic inflammation and the development of insulin resistance. In this study the aim was to investigate the effects of 12-week combined strength and endurance exercise on CD8⁺ T-cell differentiation and KYN pathway metabolites. Ninety-six elderly subjects (f/m, aged 50-70) were randomized to a control (CON) or exercise (EX) group. The EX group completed combined strength and endurance training twice weekly for one hour each time at an intensity of 60% of the one-repetition maximum for strength exercises and a perceived exertion of 15/20 for endurance exercises. The EX group was also randomly subdivided into two groups with or without a concomitant balanced diet intervention in order to examine additional effects besides exercise alone. Before and after the intervention phase, the proportions of CD8⁺ T-cell subsets and levels of KYN pathway metabolites in peripheral blood were determined.

RESULTS

The CD8⁺ EMRA T-cell subsets increased in the CON group but remained almost unchanged in the EX group (p = .02). Plasma levels of kynurenic acid (KA) increased in the EX group and decreased in the CON group (p = .03). Concomitant nutritional intervention resulted in lower levels of quinolinic acid (QA) compared with exercise alone (p = .03). Overall, there was a slight increase in the QA/KA ratio in the CON group, whereas it decreased in the EX group (p > .05).

CONCLUSIONS

Combined strength and endurance training seems to be a suitable approach to attenuate CD8⁺ T-cell differentiation in the elderly and to redirect the KYN pathway towards KA. The clinical relevance of these effects needs further investigation.

Placental Fatty Acid Metabolism and Transport in a Rat Model of Gestational Diabetes Mellitus

Gestational diabetes mellitus (GDM) is a form of heightened insulin resistance triggered during gestation. This study examines how insulin resistance alters placental long-chain polyunsaturated fatty acid (LCPUFA) transport and metabolism in a rat model of lean GDM. Pregnant Sprague Dawley rats were administered with S961, an insulin receptor antagonist (30 nmol/kg s.c. daily), or vehicle from gestational day (GD) 7 to 20. Daily maternal body weight, food, and water intake were measured. Blood pressure assessment and glucose tolerance test were done on GD20. Fetal plasma and placenta were collected on GD20 and processed for fatty acid measurement using LC-mass spectrometry. The expression of fatty acid metabolism-related genes in the placenta was assessed using RT² Profiler PCR arrays. The results were validated by qRT-PCR. Blockade of insulin receptors with S961 in pregnant rats resulted in glucose intolerance with increased fasting glucose and insulin levels. Maternal body weight gain and food and water intake were not affected; however, S961 significantly increased maternal blood pressure and heart rate. The placenta n3 and n6 LCPUFA concentrations were significantly decreased by 8% and 11%, respectively, but their levels in the fetal plasma were increased by 15% and 4%. RT2 profiler arrays revealed that placental expressions of 10 genes related to fatty acid β-oxidation (Acaa1a, Acadm, Acot2, Acox2, Acsbg1, Acsl4, Acsm5, Cpt1b, Eci2, Ehhadh) and 3 genes related to fatty acid transport pathway (Fabp2, Fabp3, Slc27a3) were significantly upregulated. In summary, lack of insulin action increased the expression of genes related to placental fatty acid β-oxidation and transport with an increased transfer of LCPUFA to the fetus. The increased lipid levels routed toward the fetus may lead to fat adiposity and later-life metabolic dysfunction.

The Effect of the Saffron Intervention on NAFLD Status and Related Gene Expression in a Rat Model

Background

According to the worldwide increasing prevalence of non-alcoholic fatty liver disease (NAFLD), the present study aimed to investigate the mechanism effects of saffron consumption on preventing NAFLD in a rat model.

Methods

In an experimental study, 12 rats were randomly divided into 2 groups to be evaluated in the prevention phase for 7 weeks. In the prevention phase, the animals were randomly assigned to either fed HFHS + 250 mg/kg saffron (S) or fed with HFHS. Afterward, parts of the liver were excised for histopathologic examination. Plasma concentrations of ALT, AST, GGT, ALP, serum lipids, insulin concentrations, plasma glucose, hs-CRP, and TAC were measured. Moreover, Also, the gene expression of 6 target genes was evaluated, including FAS, ACC1, CPT1 ،PPARα ،DGAT2, and SREBP 1-c at the beginning and end of the study. Also, the differences among groups were evaluated by the Mann-Whitney test for non-normal data and the independent t test for normal data.

Results

The prevention phase groups have a significant elevation in body weight ( P = 0.034) and food intake (P = 0.001) of the HFHS group versus HFHS + 250 mg/kg S group. Also, there was a significant difference between groups 1 and 2 for ALT (P = 0.011) and AST (P = 0.010), and TG (P = 0.040). The HFHS group had higher plasma levels of FBS (P = 0.001), insulin (P = 0.035), HOMA-IR (P = 0.032), and lower TAC (P = 0.041) versus the HFHS+ S group. Also, the difference between HFHS + 250 mg/kg S and HFHS for PPARα gene expression was significant (P = 0.030).

Conclusion

The present study showed that consumption of saffron could prevent developing NAFLD in rats at least partially through modulation in gene expression of PPARα.

Is the Co-administration of Metformin and Clomiphene Superior to Induce Ovulation in Infertile Patients With Poly Cystic Ovary Syndrome and Confirmed Insulin-Resistance: A Double Blind Randomized Clinical Trial

Objective

This study aimed to compare the effects of clomiphene citrate (CC) combined with metformin or placebo on infertile patients with poly cystic ovary syndrome (PCOS) and insulin resistance (IR).

Materials and methods

We included 151 infertile women with PCOS and IR in a university hospital from November 2015 to April 2022 in this prospective, double-blind, randomized, placebo-controlled trial. Patients were randomized into two groups; group A: received CC plus metformin (n = 76) and group B: received CC plus placebo (n = 75). The ovulation rate was the main outcome measure. Clinical pregnancy, ongoing pregnancy, live birth and abortion rates were secondary outcome measures.

Results

There was no remarkable difference in ovulation rate in two groups. Moreover, no significant changes were observed in clinical pregnancy, ongoing pregnancy, live birth and abortion rates between two groups. A larger proportion of women in group A suffered from side effects of metformin (9.3% versus 1.4%; p=0.064), although this was not significant.

Conclusion

In IR infertile women with PCOS, metformin pre-treatment did not increase the ovulation, clinical pregnancy and live birth rates in patients on clomiphene citrate.

Association between integrase strand transfer inhibitor use with insulin resistance and incident diabetes mellitus in persons living with HIV: a systematic review and meta-analysis

Whether integrase strand transfer inhibitors (INSTIs) are associated with a higher risk of incident type 2 diabetes mellitus (DM) than other antiretroviral therapies (ART) needs to be established.MEDLINE, Embase, Web of Science, and ClinicalTrials.gov registries were searched for studies published between 1 January 2000 and 15 June 2022. Eligible studies reported incident DM or mean changes in insulin resistance measured by Homeostatic Model for Insulin Resistance (HOMA-IR) in patients on INSTIs compared with other ARTs. We performed random-effects meta-analyses to obtain pooled relative risks (RRs) with 95% CIs.A total of 16 studies were pooled: 13 studies meta-analyzed for incident diabetes with a patient population of 72 404 and 3 for changes in HOMA-IR. INSTI therapy was associated with a lower risk of incident diabetes in 13 studies (RR 0.80, 95% CI 0.67 to 0.96, I²=29%), of which 8 randomized controlled trials demonstrated a 22% reduced risk (RR 0.88, 95% CI 0.81 to 0.96, I²=0%). INSTIs had a lower risk compared with non-nucleoside reverse transcriptase inhibitors (RR 0.75, 95% CI 0.63 to 0.89, I²=0%) but similar to protease inhibitor-based therapy (RR 0.78, 95% CI 0.61 to 1.01, I²=27%). The risk was lower in studies with longer follow-up (RR 0.70, 95% CI 0.53 to 0.94, I²=24%) and among ART-naïve patients (RR 0.78, 95% CI 0.65 to 0.94, I²=3%) but increased in African populations (RR 2.99, 95% CI 2.53 to 3.54, I²=0%).In conclusion, exposure to INSTIs was not associated with increased risk of DM, except in the African population. Stratified analyses suggested reduced risk among ART-naïve patients and studies with longer follow-up.International Prospective Register of Systematic Reviews (PROSPERO) registration number: CRD42021273040.

[Diagnostic performance of the FINDRISC questionnaire to identify insulin resistance in adults]

Background

Insulin resistance (IR) is a state prior to the development of type 2 diabetes (T2D) and it is reversible with lifestyle modification. However, it is underdiagnosed due to the difficulty in its measurement.

Objective

To evaluate the diagnostic performance of the FINDRISC questionnaire to identify IR.

Material and methods

An analytical cross-sectional study was performed in adults aged 20 to 60 years without previous diagnosis of T2D. Those using steroids and pregnant women were excluded. IR was diagnosed through the Triglycerides/glucose index. A ROC curve was used to establish the cut-off point for the diagnosis of IR. Sensitivity, specificity, predictive values and likelihood ratios were calculated. Risk measurement for IR was performed with the FINDRISC instrument.

Results

A total of 253 participants were included, with a prevalence of IR of 60.8%. The area under the curve of the FINDRISC instrument was 0.813 (95% confidence interval [95% CI] 0.759-0.865), with a cut-off point of 8. Sensitivity was 94.8% and specificity was 48.5%, positive predictive value was 74% and negative 86%, with a positive likelihood ratio of 1.84 and a negative of 0.11.

Conclusions

The FINDRISC instrument is a useful screening tool to identify subjects with IR at the first level of care. A score ≥ 8 identifies subjects with IR.