Insulin resistance and insulin secretory dysfunction as precursors of non-insulin-dependent diabetes mellitus. Prospective studies of Pima Indians

The paradox of fatty-acid β-oxidation in muscle insulin resistance: Metabolic control and muscle heterogeneity

The skeletal muscle is a metabolically heterogeneous tissue that plays a key role in maintaining whole-body glucose homeostasis. It is well known that muscle insulin resistance (IR) precedes the development of type 2 diabetes. There is a consensus that the accumulation of specific lipid species in the tissue can drive IR. However, the role of the mitochondrial fatty-acid β-oxidation in IR and, consequently, in the control of glucose uptake remains paradoxical: interventions that either inhibit or activate fatty-acid β-oxidation have been shown to prevent IR. We here discuss the current theories and evidence for the interplay between β-oxidation and glucose uptake in IR. To address the underlying intricacies, we (1) dive into the control of glucose uptake fluxes into muscle tissues using the framework of Metabolic Control Analysis, and (2) disentangle concepts of flux and catalytic capacities taking into account skeletal muscle heterogeneity. Finally, we speculate about hitherto unexplored mechanisms that could bring contrasting evidence together. Elucidating how β-oxidation is connected to muscle IR and the underlying role of muscle heterogeneity enhances disease understanding and paves the way for new treatments for type 2 diabetes.

Association between the triglyceride-glucose index and thyroid disorders: a cross-sectional survey and Mendelian randomization analysis

BACKGROUND

Metabolic diseases are associated with thyroid disorders. Insulin resistance is the common pathological basis of metabolic diseases. We explored the relationship between the triglyceride-glucose (TyG) index, a simple insulin-resistance marker, and thyroid disorders.

METHODS

Eligible TIDE (Thyroid Diseases, Iodine Status and Diabetes Epidemiology) subjects (n = 47,710) were screened with inclusion/exclusion criteria. Thyroid disorder prevalence among different TyG index groups was stratified by sex. Logistic regression evaluated the correlation between the TyG index and thyroid disorders. Multiple linear regression evaluated the association between the TyG index and TSH. Additionally, two-sample Mendelian randomization (MR) using published genome-wide association study data evaluated causality in the association between the TyG index and TSH.

RESULTS

Men and women with greater TyG indices had a significantly greater prevalence of thyroid disorders than individuals with the lowest quartile (Q1) of TyG index (p < 0.05). Following adjustment for confounding factors, we observed that a greater TyG index significantly increased the risk of subclinical hypothyroidism in men and women (men: Q2: odds ratio (OR) [95% confidence interval (CI)] = 1.22 [1.07-1.38], p = 0.002; Q3: OR [95% CI] = 1.28 [1.12-1.45], p < 0.001; Q4: OR [95% CI] = 1.29 [1.12-1.50], p = 0.001; women: Q2: OR [95% CI] = 1.25 [1.12-1.39], p < 0.001; Q3: OR [95% CI] = 1.47 [1.31-1.64], p < 0.001; Q4: OR [95% CI] = 1.61 [1.43-1.82], p < 0.001). Only among women was the highest TyG index quartile associated with hypothyroidism (OR [95% CI] = 1.70 [1.15-2.50], p = 0.007). Additionally, in men, the association exists only in the more than adequate iodine intake population. In women, the relationship between the TyG index and thyroid disorders disappears after menopause. Furthermore, the TyG index exhibited a linear positive correlation with TSH levels. The MR analysis results revealed a causal relationship between a genetically determined greater TyG index and increased TSH (inverse-variance weighting (IVW): OR [95% CI] = 1.14 [1.02-1.28], p = 0.020); however, this causal relationship disappeared after adjusting for BMI in multivariable MR (MVMR) analysis (MVMR-IVW: OR 1.03, 95% CI 0.87-1.22, p = 0.739).

CONCLUSIONS

A greater TyG index is associated with hypothyroidism and subclinical hypothyroidism and varies by sex and menopausal status. MR analysis demonstrated that the causal relationship between a genetically determined greater TyG index and elevated TSH levels is confounded or mediated by BMI.

Insulin resistance before type 2 diabetes onset is associated with increased risk of albuminuria after diabetes onset: A prospective cohort study

AIM

Reduced renal insulin signalling is implicated in the pathogenesis of albuminuria. We sought to investigate whether insulin action and secretion, measured before diabetes onset, are associated with the development of albuminuria after diabetes onset.

MATERIALS AND METHODS

Baseline body composition, insulin sensitivity by hyperinsulinaemic-euglycaemic clamp at submaximal and maximal insulin stimulation (240 and 2400 pmol/m2/min; M-low and M-high), and insulin secretion by intravenous glucose tolerance test [acute insulin response (AIR)] were measured in 170 Southwestern Indigenous American adults who subsequently developed diabetes. After diabetes onset and during the median follow-up of 13.6 years, 81 participants (48%) developed albuminuria (urine albumin-to-creatinine ratio ≥30 mg/g). Separate associations of M-low, M-high and AIR (per 1-SD change) with the risk of albuminuria were assessed by Cox regression models adjusted for age, sex and body fat (%).

RESULTS

Participants who developed albuminuria were of similar age (26.4 ± 5.4 vs. 27.5 ± 6.1 years), sex (46% vs. 48% male), body fat (36.4 ± 7.5 vs. 35.7 ± 7.9%) and AIR [2.3 ± 0.3 vs. 2.3 ± 0.3, pmol/L (log)] as those who did not develop albuminuria but had lower insulin sensitivity [M-low: 0.33 ± 0.08 vs. 0.36 ± 0.12, p = .03; M-high: 0.87 ± 0.11 vs. 0.91 ± 0.12, p = .02; mg/kg-metabolic body size/min (log)]. In separate adjusted models, lower M-low and M-high were both associated with an increased risk for albuminuria [hazard ratio (HR) 1.51, 95% confidence interval (CI) 1.14, 2.00, p = .004; HR 1.31, 95% CI 1.06, 1.63, p = .01), whereas AIR was not (HR 1.15, 95% CI 0.87, 1.56, p = .3).

CONCLUSIONS

Lower insulin sensitivity is associated with the development of albuminuria, suggesting a role for insulin signalling in the pathogenesis of proteinuria.

Comparative analysis of hemodialysis and peritoneal dialysis on the risk of new onset diabetes mellitus

BACKGROUND

Diabetes mellitus is a significant risk factor for cardiovascular events and mortality in dialysis patients. The impact of different dialysis modalities on the risk of new onset diabetes mellitus (NODM) remains a subject of debate. Previous studies did not adequately account for critical confounding factors such as pre-dialysis glycemic status, medication use, and nutritional status, which may influence the association between dialysis modality and NODM risk.

METHODS

We conducted a retrospective cohort study of 1426 non-diabetic end-stage renal disease (ESRD) patients who underwent either hemodialysis (HD) or peritoneal dialysis (PD) at a single medical center. We used different statistical methods, adjusting for potential confounding factors, and accounted for competing risk of death.

RESULTS

Over 12 years, 331 patients (23 %) developed NODM. After adjusting for potential confounding factors and mortality, PD patients had a significantly higher risk of NODM compared to HD patients (adjusted HR 1.52, p = 0.001). A propensity-matched cohort sensitivity analysis yielded similar results. Among patients with prediabetes, those receiving PD had a 2.93 times higher risk of developing NODM than those receiving HD (p for interaction <0.001), whereas no significant difference was observed among euglycemic patients. NODM was also associated with a 1.78 times increased risk of major cardiovascular events.

CONCLUSION

Our study provides evidence that PD treatment may increase the risk of NODM in ESRD patients, particularly among those with preexisting prediabetes. These findings highlight the importance of personalized treatment approaches, and nephrologists should consider prediabetes when choosing the dialysis modality for their patients.

Development of a New Model of Insulin Sensitivity in Patients With Type 2 Diabetes and Association With Mortality

CONTEXT

Despite being one of the major drivers of diabetes incidence, the degree of insulin resistance in patients with type 2 diabetes (T2D) is not usually evaluated in clinical practice or in large epidemiologic studies.

OBJECTIVE

To identify a model of insulin sensitivity using widely available clinical and laboratory parameters in patients with T2D and evaluate its association with all-cause and cardiovascular mortality.

METHODS

One hundred forty patients with T2D underwent a euglycemic hyperinsulinemic clamp to measure total body glucose disposal rate (mg kg-1 minute-1). We used demographic, clinical, and common laboratory parameters to estimate insulin sensitivity (IS) via stepwise linear regression on 85 patients (training cohort) and validated it in the remaining 55 (validation cohort). The identified equation was then applied to 3553 patients with T2D from the 1999-2010 cycles of the National Health and Nutrition Examination Survey (NHANES) to evaluate its association with all-cause and cardiovascular mortality up to December 2015.

RESULTS

The best model included triglycerides, gamma glutamyl transpeptidase, albumin excretion rate, and body mass index. The identified IS score correlated well with the clamp-derived glucose disposal rate in both the training (r = 0.77, P < .001) and the validation (r = 0.74, P < .001) cohorts. In the NHANES cohort, after a median follow-up of 8.3 years, 1054 patients died, 265 of cardiovascular causes. In a multivariable Cox proportional hazard model adjusted for age, sex, race-ethnicity, education, cigarette smoke, total cholesterol, chronic kidney disease, blood pressure, prevalent cardiovascular disease, and alcohol consumption, a higher estimated IS was associated with a lower risk of both all-cause and cardiovascular mortality.

CONCLUSION

We propose a new model of IS in patients with T2D based on readily available clinical and laboratory data. Its potential applications are in both diagnosis as well as prognostication.

The Association Between the Triglyceride to High-Density Lipoprotein Cholesterol Ratio and the Incidence of Type 2 Diabetes Mellitus in the Japanese Population

Abstract Aims: To explore whether the triglyceride to high-density lipoprotein cholesterol ratio (TG/HDL-C) was independently associated with the risk of incident type 2 diabetes mellitus (T2DM) in a large Japanese cohort. Methods: A secondary analysis was performed using open-access data from a retrospective cohort study. A total of 12,716 eligible participants who had standard medical examinations at the Murakami Memorial Hospital were included in this study. New-onset T2DM was the main outcome during follow-up. The risk of T2DM based on the TG/HDL-C ratio was evaluated using Cox regression analysis and Kaplan-Meier analysis. Subgroup analysis was performed to understand further the significance of the TG/HDL-C ratio in particular populations. To assess the potential of the TG/HDL-C ratio for predicting T2DM, a receiver operating characteristic (ROC) analysis was performed. Results: One hundred fifty new-onset T2DM cases were observed during a median follow-up of 5.39 years. The incidence of T2DM increased with a rise in the TG/HDL-C ratio based on the Kaplan-Meier curves (P < 0.0001). After controlling for potential confounding variables, the TG/HDL-C ratio was positively related to incidence of T2DM (hazard ratio = 1.08, 95% confidence interval: 1.01-1.15, P = 0.0239). In subgroup analysis, those with a body mass index of ≥18.5 and <24 kg/m2 showed a significantly positive relationship. The area under the ROC curve for the TG/HDL-C ratio as a T2DM predictor was 0.684. The optimal TG/HDL-C ratio cutoff value for T2DM was 1.609, with a sensitivity of 54.7% and a specificity of 73.6%. Conclusion: The authors' results showed a significant relationship between the TG/HDL-C ratio and the incidence of T2DM in the Japanese population.

The role of m6A modification in type 2 diabetes: A systematic review and integrative analysis

This study focuses on the latest developments in the studies of m6A modification and provides an up-to-date summary of the association between m6A modification and type 2 diabetes (T2D). The possible mechanisms of m6A related to T2D were summarized by literature review. The differentially expressed genes (DEGs) of m6A methylase in T2D were analyzed from 12 datasets in Gene Expression Omnibus (GEO). The associations between m6A level and T2D were explored in four electronic databases, including PubMed, EmBase, Web of Science and CNKI. Standard mean difference (SMD) and 95 % confidence interval (95 %CI) was calculated to assess the total effect in integrative analysis. Differential expression genes detected in at least three of six tissues were ZC3H13, YTHDC1/2, and IGF2BP2. LRPPRC were differentially expressed in five tissues except in arterial tissue. A total of 6 studies were included for integrative analysis. The mean m6A levels were significantly lower in T2D than those in normal controls (SMD = -1.35, 95 %CI: -2.58 to -0.11). This systematic review and integrative analysis summarize the previous studies on the association between m6A modification and T2D and the possible role of m6A modification in the progression of T2D, such as abnormal blood glucose, abnormal pancreatic β-cell function, insulin resistance, and abnormal lipid metabolism. The integrative analysis showed that decreased level of m6A was associated with T2D. These findings provide new targets for early detection and treatment for T2D.

Higher glucose and insulin responses to a mixed meal are associated with increased risk of diabetic retinopathy in Indigenous Americans

PURPOSE

Prior research has focused on glucose/insulin responses to meal challenges to create personalized diets to improve health, though it is unclear if these responses predict chronic diseases. We aimed to identify glucose and insulin responses to a mixed meal tolerance test (MMTT) that predict the development of diabetic retinopathy (DR) and compare the predictive abilities with the oral glucose tolerance test (OGTT).

METHODS

Indigenous American adults without diabetes (n = 168) underwent a 4-h MMTT, body composition assessment, and a 3-h OGTT at baseline. During follow-up (median 13.4 years), DR was diagnosed by direct ophthalmoscopy (n = 28) after onset of type 2 diabetes. Total and incremental area under the curve (AUC and iAUC) were calculated from glucose/insulin responses after the MMTT and OGTT.

RESULTS

In separate Cox proportional hazards models adjusted for age, sex, and body fat (%), MMTT glucose AUCs (180-min and 240-min) and iAUC (180-min) predicted DR (HR 1.50, 95% CI 1.06, 2.12; HR 1.50, 95% CI 1.05, 2.14; HR 1.58, 95% CI 1.01, 2.46). The predictive abilities were better than the fasting OGTT glucose (p < 0.01) but similar to the 120-min OGTT glucose (p = 0.53). MMTT insulin AUCs (180-min and 240-min) and iAUC (180-min) also predicted DR (HR 1.65, 95% CI 1.09, 2.51; HR 1.58, 95% CI 1.00, 2.35; HR 1.53 95% CI 1.06, 2.22) while insulin AUC and iAUC from the OGTT did not (p > 0.05).

CONCLUSIONS

Higher MMTT glucose and insulin responses predicted DR and were comparable to the OGTT, supporting the use of a meal challenge for precision nutrition.

TRIAL REGISTRATIONS

Clinical Trial Registry: ClinicalTrials.gov identifier: NCT00340132, NCT00339482.

Increased pretreatment triglyceride glucose-body mass index associated with poor prognosis in patients with advanced non-small cell lung cancer

BACKGROUND

The association between the triglyceride glucose-body mass index (TyG-BMI) and various health outcomes has been postulated. Nonetheless, the application of TyG-BMI in predicting the prognosis of non-small cell lung cancer (NSCLC) remains poorly understood. Our objective was to explore the association between TyG-BMI and both progression-free survival (PFS) and overall survival (OS) in patients with advanced NSCLC.

METHODS

A retrospective study was conducted on the data of 426 patients diagnosed with advanced NSCLC between 2018 and 2022. The TyG-BMI values were derived from the serum triglyceride, fasting plasma glucose, and BMI measurements obtained at the time of diagnosis. Cox proportional hazards regression models were applied to examine the impact of TyG-BMI on both progression-free survival (PFS) and overall survival (OS) in advanced NSCLC.

RESULTS

The median duration of follow-up was 899 days, with an interquartile range of 256-1486 days. In comparison to the lowest tertile of TyG-BMI, the highest tertile model demonstrated a significant association with worse OS (hazard ratio [HR]: 1.85; 95% confidence interval [CI]: 1.21-2.80; P = 0.001) and PFS (HR: 2.10; 95% CI: 1.40-3.10; P < 0.001). Each standard deviation increase in TyG-BMI corresponded to a 10% reduction in OS (95% CI: 1%-24%) and a 14% reduction in PFS (95% CI: 2%-27%). Subgroup analyses indicated that cigarette smokers and individuals with elevated C-reactive protein (CRP) levels exhibited a notably unfavorable prognosis in relation to TyG-BMI-associated advanced NSCLC, as evident in both OS (P for interaction: 0.046 for smoking) and PFS (P for interaction: 0.033 for smoking and 0.049 for CRP).

CONCLUSION

Our data revealed a causal relationship between TyG-BMI and an unfavorable prognosis in patients with advanced NSCLC. Furthermore, this independent association exhibits greater significance in individuals who are smokers and exhibit higher levels of CRP.

Sleep extension and cardiometabolic health: what it is, possible mechanisms and real-world applications

Short sleep duration is associated with heightened cardiometabolic disease risk and has reached epidemic proportions among children, adolescents and adults. Potential mechanisms underlying this association are complex and multifaceted, including disturbances in circadian timing, food intake and appetitive hormones, brain regions linked to control of hedonic eating, physical activity, an altered microbiome and impaired insulin sensitivity. Sleep extension, or increasing total sleep duration, is an emerging and ecologically relevant intervention with significant potential to advance our understanding of the mechanisms underlying the association between short sleep duration and the risk of cardiometabolic disease. If effective, sleep extension interventions have potential to improve cardiometabolic health across the lifespan. Existing data show that sleep extension is feasible and might have potential cardiometabolic health benefits, although there are limitations that the field must overcome. Notably, most existing studies are short term (2-8 weeks), use different sleep extension strategies, analyse a wide array of cardiometabolic health outcomes in different populations and, frequently, lack adequate statistical power, thus limiting robust scientific conclusions. Overcoming these limitations will require fully powered, randomized studies conducted in people with habitual short sleep duration and existing cardiometabolic risk factors. Additionally, randomized controlled trials comparing different sleep extension strategies are essential to determine the most effective interventions. Ongoing and future research should focus on elucidating the potential cardiometabolic health benefits of sleep extension. Such studies have high potential to generate crucial knowledge with potential to improve health and quality of life for those struggling with short sleep duration.

Physiologic hormone administration improves HbA1C in Native Americans with type 2 diabetes: A retrospective study and review of insulin secretion and action

Insulin is secreted in pulses from pancreatic beta-cells, and these oscillations maintain fasting plasma glucose levels within a narrow normal range. Within islets, beta-cells exhibit tight synchronization of regular oscillations. This control circuit is disrupted in type 2 diabetes, and irregularities in pulse frequency and amplitude occur. The prevalence of type 2 diabetes is three times higher in American Indian and Native Alaskans compared to Whites, and their genetic ancestry is associated with low beta-cell function. Obesity in this population compounds their vulnerability to adverse outcomes. The purpose of this article is to review insulin secretion and action and its interaction with race. We also present the results from a 6-month retrospective chart review of metabolic outcomes following intravenous physiologic hormone administration to 10 Native Americans. We found reductions in hemoglobin A1C (baseline: 9.03% ± 2.08%, 6 months: 7.03% ± 0.73%, p = 0.008), fasting glucose (baseline: 176.0 ± 42.85 mg/dL, 6 months: 137.11 ± 17.05 mg/dL, p = 0.02), homeostatic model assessment of insulin resistance (baseline: 10.39 ± 4.66, 6 months: 7.74 ± 4.22, p = 0.008), and triglycerides (baseline: 212.20 ± 101.44, 6 months: 165.50 ± 76.48 mg/dL, p = 0.02). Physiologic hormone administration may improve components of the metabolic syndrome. The therapy warrants investigation in randomized controlled trials.

Observations of parent-adolescent interactions relate to food parenting practices and adolescent disordered eating in adolescents at risk for adult obesity

Adolescent disordered eating and obesity are interrelated and adversely relate to mental and metabolic health. Parental feeding practices have been associated with adolescent disordered eating and obesity. Yet, observable interactions related to food parenting have not been well characterized. To address this gap, N = 30 adolescents (M ± SD 14 ± 2 year) at risk for adult obesity due to above-average body mass index (BMI ≥70th percentile) or parental obesity (BMI ≥30 kg/m2 ) participated in a video-recorded parent-adolescent task to discuss a food/eating-related disagreement. Interactions were coded for individual/dyadic affect/content using the Interactional Dimensions Coding System. We examined associations of interaction qualities with parent-reported food practices, adolescent disordered eating behaviors/attitudes, and insulin resistance. Reported parenting practices were correlated with multiple interaction qualities (p-values <0.05), with the most consistent correspondence between parent-reported pressure to eat (e.g., pressure to eat more healthy foods) and negative aspects of parent-adolescent interactions. Also, after accounting for adolescent age, sex, and BMI-standard score, parent-adolescent interaction qualities were associated with adolescents' disordered eating and insulin resistance. Specifically, greater adolescent problem-solving related to less adolescent global disordered eating, shape, and weight concern (p-values <0.05); adolescent autonomy related to less weight concern (p = 0.03). Better parent communication skills were associated with less adolescent eating concern (p = 0.04), and observed dyadic mutuality related to adolescents' lower insulin resistance (p = 0.03). Parent-adolescent interaction qualities during food/eating-related disagreements show associations with parent-reported food practices and adolescent disordered eating. This method may offer a tool for measuring the qualities of parent-adolescent food/eating-related interactions. A nuanced understanding of conversations about food/eating may inform family-based intervention in youth at-risk for adult obesity.

Trends in HOMA-IR values among South Korean adolescents from 2007-2010 to 2019-2020: a sex-, age-, and weight status-specific analysis

BACKGROUND/OBJECTIVES

An increase in obesity prevalence may lead to an increase in the HOMA-IR value. This study aimed to investigate changes in age- and sex-specific homeostasis model assessment of insulin resistance (HOMA-IR) values among South Korean adolescents, using data from the Korean National Health and Nutrition Examination Survey (KNHANES) IV, V, and VIII conducted between 2007-2010 and 2019-2020.

SUBJECTS/METHODS

Overall, 4621 adolescents aged 10-18 years were evaluated, including 3473 from the 2007-2010 dataset and 1148 from the 2019-2020 dataset. The mean HOMA-IR values and percentile curves were evaluated by age, sex, and weight status.

RESULTS

The mean HOMA-IR values peaked at puberty in both sexes and further increased during puberty in the 2019-2020 dataset (boys 5.21, 95% confidence interval [CI] 4.16-6.26; girls 5.21, 95% CI 3.09-7.33) compared with the 2007-2010 dataset (boys 3.25, 95% CI 3.04-3.47; girls 3.58, 95% CI 3.31-3.85). Both groups (with normal-weight and overweight/obesity) exhibited a peak HOMA-IR value during puberty in both sexes and both datasets, although the group with overweight/obesity had a higher and wider peak age range. While the mean HOMA-IR values did not change in adolescents with normal-weight, they increased during puberty and post-puberty in boys with overweight/obesity.

CONCLUSIONS

HOMA-IR values should be interpreted considering sex, weight status, and pubertal stages. In particular, during the pubertal period, insulin resistance (IR) can coexist not only due to weight-related factors but also as a result of the distinct hormonal changes characteristic of puberty. Over the 10-year period, the mean HOMA-IR values increased in the group with overweight/obesity during puberty and post-puberty, highlighting the need for active intervention to prevent metabolic complications in adolescents with overweight/obesity.

One-hour glucose is an earlier marker of dysglycemia than two-hour glucose

AIMS

The timing of increase in 1-hour PG and its utility as an earlier predictor of both prediabetes (PreDM) and type 2 diabetes (T2D) compared to 2-hour PG (2 h-PG) are unknown. To evaluate the timing of crossing of the 1 h-PG ≥ 155 mg/dl (8.6 mmol/L) for PreDM and 209 mg/dl (11.6 mmol/L) for T2D and respective current 2 h-PG thresholds of 140 mg/dl (7.8 mmol/L) and 200 mg/dl (11.1 mmol/L).

METHODS

Secondary analysis of 201 Southwest Native Americans who were followed longitudinally for 6-10 years and had at least 3 OGTTs.

RESULTS

We identified a subset of 43 individuals who first developed PreDM by both 1 h-PG and 2 h-PG criteria during the study. For most (32/43,74%), 1 h-PG ≥ 155 mg/dl was observed before 2 h-PG reached 140 mg/dl (median [IQR]: 1.7 [-0.25, 4.59] y; mean ± SEM: 5.3 ± 1.9 y). We also identified a subset of 33 individuals who first developed T2D during the study. For most (25/33, 75%), 1 h-PG reached 209 mg/dl earlier (median 1.0 [-0.56, 2.02] y; mean ± SEM: 1.6 ± 0.8 y) than 2 h-PG reached 200 mg/dl, diagnostic of T2D.

CONCLUSIONS

1 h-PG ≥ 155 mg/dl is an earlier marker of elevated risk for PreDM and T2D than 2 h-PG ≥ 140 mg/dl.

Increased glutamate in type 2 diabetes in the Korean population is associated with increased plasminogen levels

BACKGROUND

Glutamate is a major neurotransmitter, although it causes cytotoxicity and inflammation in nonneuronal organs. This study aimed to investigate the metabolic disorders in which glutamate, associated with type 2 diabetes onset, is induced in the liver.

METHODS

An analysis of Korean community-based Ansan-Ansung cohort study data as well as functional research using in vitro and mouse models were performed.

RESULTS

Groups with high plasma glutamate levels (T2, T3) had a significantly increased risk of diabetes incidence after 8 years, compared to the group with relatively low glutamate levels (T1). Analysis of the effect of glutamate on diabetes onset in vitro showed that glutamate induces insulin resistance by increasing glucose-related protein 78 (GRP78) and phosphoenolpyruvate carboxykinase (PEPCK) expression in SK-Hep-1 human liver cells. In addition, three different genes, FRMB4B, PLG, and PARD3, were significantly associated with glutamate and were identified via genome-wide association studies. Among glutamate-related genes, plasminogen (PLG) levels were most significantly increased in several environments in which insulin resistance was induced, and was also upregulated by glutamate. Glutamate-induced increase in PLG in liver cells was caused by metabotropic glutamate receptor 5 activation, and PLG levels were also upregulated after extracellular secretion. Moreover, glutamate increased the expression of plasminogen activator inhibitor-1 (PAI-1). Thus, extracellular secreted PLG cannot be converted to plasmin (fibrinolytic enzyme) by increased PAI-1.

CONCLUSIONS

Increased glutamate is closely associated with the development of diabetes, and it may cause metabolic disorders by inhibiting the fibrinolytic system, which plays an important role in determining blood clots, a hallmark of diabetes.

Diet and Acanthosis Nigricans over a Two-Year Period in Children of the Pacific Region

BACKGROUND

The impact that dietary carbohydrates have on children developing type 2 diabetes remains controversial. Furthermore, there are limited pediatric longitudinal studies on changes in body mass index (BMI) and diet related to the development of acanthosis nigricans (AN), a risk factor associated with type 2 diabetes.

METHODS

Two 24 h dietary records were collected for 558 children, 2-8 years of age, at baseline and at a 2-year follow-up. Data on age, sex, BMI, and the presence of AN were also collected at each time point from the Children's Healthy Living Program. Logistic regression was used to determine factors associated with the presence of AN at follow-up. Multinominal regression was used to determine factors associated with changes in AN status. Linear regression was used to measure the associations between changes in dietary intake and in the Burke Score for AN.

RESULTS

AN was present in 28 children at baseline and 34 children at follow-up. Adjusting for the presence of AN at baseline, age, sex, study group, baseline BMI, change in BMI z-score, time between assessments, and baseline intake, an increase from baseline for each teaspoon of sugar and serving of carbohydrate-rich food increased the risk for having AN at follow-up by 9% and 8%, respectively (p ≤ 0.05). An increased intake of added sugar (teaspoons) increased the risk of developing AN by 13% (p ≤ 0.01) and an increase in servings of foods rich in starch increased the risk of developing AN by 12% (p ≤ 0.01) compared to children who never had AN. Increasing the intake of fruit was also associated with decreased Burke Scores using multiple regression. However, the intake of energy and macronutrients were not associated with AN.

CONCLUSIONS

Added sugar and foods rich in starch were independently associated with the occurrence of AN, suggesting the type of carbohydrates consumed is a factor in AN occurrence.

TXLNG improves insulin resistance in obese subjects in vitro and in vivo by inhibiting ATF4 transcriptional activity

Lipotoxicity contributes to insulin resistance and dysfunction of pancreatic β-cells. Insulin promotes 3T3-L1 preadipocyte differentiation and facilitates glucose entry into muscle, adipose, and other tissues. In this study, differential gene expression was analyzed using four datasets, and taxilin gamma (TXLNG) was the only shared downregulated gene in all four datasets. TXLNG expression was significantly reduced in obese subjects according to online datasets and in high-fat diet (HFD)-induced insulin-resistant (IR) mice according to experimental investigations. TXLNG overexpression significantly improved IR induced by HFD in mouse models by reducing body weight and epididymal adipose weight, decreasing mRNA expression of pro-inflammatory factors interleukin 6 (IL-6) and tumor necrosis factor alpha (TNF-α), and reducing adipocyte size. High-glucose/high-insulin-stimulated adipocytes exhibited decreased TXLNG and increased signal transducer and activator of transcription 3 (STAT3) and activating transcription factor 4 (ATF4). IR significantly decreased glucose uptake, cell surface glucose transporter type 4 (GLUT4) levels, and Akt phosphorylation, while increasing the mRNA expression levels of IL-6 and TNF-α in adipocytes. However, these changes were significantly reversed by TXLNG overexpression, while they were exacerbated by TXLNG knockdown. TXLNG overexpression had no effect on ATF4 protein levels, while ATF4 overexpression increased ATF4 protein levels. Furthermore, ATF4 overexpression notably abolished the improvements in IR adipocyte dysfunction caused by TXLNG overexpression. In conclusion, TXLNG improves IR in obese subjects in vitro and in vivo by inhibiting ATF4 transcriptional activity.

High fructose-induced skeletal muscle insulin resistance could be alleviated by berberine via AMPD1 and ADSL

AMP-activated protein kinase (AMPK) is a master regulator of energy homeostasis that is activated in response to an elevated intracellular AMP/ATP ratio. Although many studies have shown berberine is an AMPK activator widely used in metabolic syndrome, how to properly control AMPK activity remains obscure. Our present study aimed to examine the protective effect of berberine against fructose-induced insulin resistance in rats and L6 cells, as well as its potential activation mechanism on AMPK. The results showed that berberine effectively reversed body weight gain, Lee's index, dyslipidemia and insulin intolerance. Moreover, berberine alleviated inflammatory response, antioxidant capacity and promoted glucose uptake in vivo and in vitro. The beneficial effect was associated with upregulation of both Nrf2 and AKT/GLUT4 pathways, which were regulated by AMPK. Notably, berberine could increase the level of AMP and the ratio of AMP/ATP, then further activate AMPK. Mechanistic experiments revealed that berberine suppressed the expression of adenosine monophosphate deaminase 1 (AMPD1) and promoted the expression of adenylosuccinate synthetase (ADSL). Taken together, berberine exerted excellent therapeutic effect on insulin resistance. And its mode of action may be related to the AMP-AMPK pathway by regulating AMPD1 and ADSL.

Diagnostic criteria and etiopathogenesis of type 2 diabetes and its complications: Lessons from the Pima Indians

The Phoenix Epidemiology and Clinical Research Branch of the National Institute of Diabetes and Digestive and Kidney Diseases has conducted prospective studies of diabetes and its complications in the Pima Indians living in Arizona, USA for over 50 years. In this review we highlight areas in which these studies provided vital insights into the criteria used to diagnose type 2 diabetes, the pathophysiologic changes that accompany the development of type 2 diabetes, and the course and determinants of diabetes complications-focusing specifically on diabetic kidney disease. We include data from our longitudinal population-based study of diabetes and its complications, studies on the role of insulin resistance and insulin secretion in the pathophysiology of type 2 diabetes, and in-depth studies of diabetic kidney disease that include measures of glomerular function and research kidney biopsies. We also focus on the emerging health threat posed by youth-onset type 2 diabetes, which was first seen in the Pima Indians in the 1960s and is becoming an increasing issue worldwide.

The impact of high-fat feeding and parkin overexpression on skeletal muscle mass, mitochondrial respiration, and H2O2 emission

Obesity is a major risk factor for developing various health problems, including insulin resistance and type 2 diabetes. Although controversial, accumulation of mitochondrial dysfunction, and notably an increase in mitochondrial reactive oxygen species (ROS) production, was proposed as a key contributor leading to obesity-induced insulin resistance. Here, our goal was to investigate whether Parkin overexpression, a key regulator of the removal of dysfunctional mitochondria through mitophagy, could confer protection against obesity-induced mitochondrial dysfunction. To this end, intramuscular injections of adeno-associated viruses (AAVs) were performed to overexpress Parkin in limb muscle of 6-mo-old mice fed a control diet (CD) or a high-fat diet (HFD) for 12 wk. An AAV-expressing the green fluorescent protein (GFP) was used as control. HFD increased fat mass, altered glycemia, and resulted in insulin resistance. Parkin overexpression resulted in an increase in muscle mass in both CD and HFD mice. In CD mice, Parkin overexpression increased maximal mitochondrial respiration and lowered H₂O₂ emission. HFD increased mitochondrial respiration and, surprisingly, also lowered H₂O₂ emission. Parkin overexpression did not significantly impact mitochondrial function in HFD mice. Taken altogether, our results indicate that Parkin overexpression positively impacts muscle and mitochondrial health under basal conditions and challenges the notion that intrinsic mitochondrial dysfunction is involved in the development of insulin resistance caused by high-fat feeding.

Bariatric surgery normalizes diabetes risk index by one month post-operation

AIM

The Diabetes risk index (DRI) is a composite of NMR-measured lipoproteins and branched chain amino acids predictive of diabetes mellitus development. Bariatric surgery is indicated in patients with severe obesity, many of whom are at high-risk for developing diabetes. Substantial weight loss occurs following bariatric surgery and sustained weight loss likely contributes to reductions in the development of diabetes and cardiovascular disease. However, some evidence suggests that bariatric surgical procedures themselves may contribute to reducing risk of these conditions independent of weight loss. We aimed to investigate DRI and its association with reductions in body weight and adiposity over one year following bariatric surgery.

METHODS

We examined 51 severely obese premenopausal women without diabetes. DRI, BMI, body weight and waist measurements were made before and at 1, 6 and 12 months after Roux-en-Y Gastric Bypass (RYGB) or Sleeve Gastrectomy. Values were compared to healthy women with normal BMI (18.5-24.9 kg/m2; n = 15).

RESULTS

Non-diabetic women with severe obesity (BMI 44.7 ± 6.2 kg/m2) exhibited significantly elevated DRI scores prior to surgery versus controls (35 [26, 39] vs 12 [1, 20]; p < 0.0001). At 1 month after surgery, BMI decreased 5.1 ± 1.1 kg/m2, but DRI decreased so that it no longer differed from that of normal BMI controls (1.9 [1, 17] vs control 12 [1, 20]; p = 0.35). Subjects continued to lose weight, whereas DRI remained similar, throughout follow-up with DRI 1.0 [1, 7] at 12 months. Changes in DRI did not correlate with changes in BMI, body weight or waist circumference at any time during follow-up. There was no difference in change in DRI between surgical procedures or pre-operative metabolic syndrome status.

CONCLUSIONS

Our analysis of DRI scores supports the capacity of bariatric surgery to reduce risk of developing diabetes in severely obese individuals. Our findings suggest that bariatric surgical techniques may have inherent effects that improve cardiometabolic risk independent of reductions in body weight or adiposity.

A nonlinear associations of metabolic score for insulin resistance index with incident diabetes: A retrospective Chinese cohort study

Background

The Metabolic score of insulin resistance (METS-IR) has recently been accepted as a reliable alternative to insulin resistance (IR), which was demonstrated to be consistent with the hyperinsulinemic-euglycemic clamp. Few pieces of research have focused on the relationship between METS-IR and diabetes in Chinese. The purpose of this research was to explore the effect of METS-IR on new-onset diabetes in a large multicenter Chinese study.

Methods

At the baseline of this retrospective longitudinal research, 116855 participators were included in the Chinese cohort study administered from 2010 to 2016. The subjects were stratified by quartiles of METS-IR. To assess the effect of METS-IR on incident diabetes, the Cox regression model was constructed in this study. Stratification analysis and interaction tests were applied to detect the potential effect of METS-IR and incident diabetes among multiple subgroups. To verify whether there was a dose-response relationship between METS-IR and diabetes, a smooth curve fitting was performed. In addition, to further determine the performance of METS -IR in predicting incident diabetes, the receiver operating characteristic curve (ROC) was conducted.

Results

The average age of the research participators was 44.08 ± 12.93 years, and 62868 (53.8%) were men. METS-IR were significant relationship with new-onset diabetes after adjusting for possible variables (Hazard ratio [HR]: 1.077; 95% confidence interval [CI]: 1.073-1.082, P &lt; 0.0001), the onset risk for diabetes in Quartile 4 group was 6.261-fold higher than those in Quartile 1 group. Moreover, stratified analyses and interaction tests showed that interaction was detected in the subgroup of age, body mass index, systolic blood pressure, diastolic blood pressure, and fasting plasma glucose, there was no significant interaction between males and females. Furthermore, a dose-response correlation was detected between METS-IR and incident diabetes, the nonlinear relationship was revealed and the inflection point of METS-IR was calculated to be 44.43. When METS-IR≥44.43, compared with METS-IR &lt; 44.43, the trend was gradually saturated, with log-likelihood ratio test P &lt; 0.001. Additionally, the area under receiver operating characteristic of the METS-IR in predicting incident diabetes was 0.729, 0.718, and 0.720 at 3, 4, and 5 years, respectively.

Conclusions

METS-IR was correlated with incident diabetes significantly, and showed a nonlinear relationship. This study also found that METS-IR had good discrimination of diabetes.

Impaired Early Insulin Response to Glucose Load Predicts Episodic Memory Decline: A 10-Year Population-Based Cohort Follow-Up of 45-74-Year-Old Men and Women

BACKGROUND

Diabetes increases the risk for cognitive decline, but the mechanisms behind this association remain unknown. Impaired early insulin secretion in elderly men and insulin resistance, both of which are pathophysiological features of type 2 diabetes, have previously been linked to Alzheimer's disease.

OBJECTIVE

To examine if the early insulin response to oral glucose load predicts cognitive performance after 10 years in men and women aged 45-74 years.

METHODS

This study was based on a subpopulation of the Health 2000 Survey, a Finnish nationwide, population-based health examination study, and its follow-up, the Health 2011 Study. In total, 961 45-74-year-old individuals (mean age at baseline 55.6 years, 55.8% women) were examined. An oral glucose tolerance test was performed in 2001-2002, and early insulin response was defined as the ratio of the 30-min increment in insulin concentration to that of glucose concentration. Cognitive function was evaluated at baseline and follow-up with categorical verbal fluency, word-list learning, and word-list delayed recall. Statistical analyses were performed using multivariable linear models adjusted for age, sex, education, APOE&z.epsi;4 genotype, vascular risk factors including diabetes, and depressive symptoms.

RESULTS

A lower early insulin response to glucose load predicted lower performance (β: 0.21, p = 0.03) and greater decline (β: 0.19, p = 0.03) in the word-list delayed recall test. Baseline early insulin response did not predict verbal fluency or word-list learning (all p-values≥0.13).

CONCLUSION

Our results suggest that decreased early insulin secretion predicts episodic memory decline in middle-aged to elderly men and women.

Prenatal EGCG consumption causes obesity and perturbs glucose homeostasis in adult mice

Epigallocatechin gallate (EGCG) has a wide consumption for its health advantages. The current study investigates the effects of prenatal EGCG administration on glucose metabolism and obesity in adulthood. Pregnant C57BL/6J mice were supplemented with EGCG in drinking water (3 µg/mL) for 16 d. Abdominal obesity was observed in both male and female adult mice, which was associated with the upregulation of adipose-specific genes, including C/ebpα and Srebf1 (Srebf1 only in males), and the downregulation of genes related to lipolysis, such as Acox1, Atgl and Pdk4 (only in males) in visceral adipose tissue. Elevated fasting glucose levels and hyperinsulinemia were observed in adult males, while females exhibit lower glucose level in glucose tolerance test, which might be due to reduced glucagon levels. Though hepatic expression of the insulin receptor signaling pathway was upregulated in males and was not altered in females, prenatal treatment with EGCG downregulated the expression of this signaling pathway in the skeletal muscle of adult mice, which was further demonstrated in primary human skeletal muscle cells treated with EGCG. The methylation levels in promotor of genes related to the insulin receptor signaling were matched with their transcription in mice, while the expression of acetylated histones was downregulated in human skeletal muscle cells. These results suggest that EGCG consumption during pregnancy should be a risk factor for the disruption of glucose homeostasis in adulthood.

American Association of Clinical Endocrinology Clinical Practice Guideline: Developing a Diabetes Mellitus Comprehensive Care Plan-2022 Update

OBJECTIVE

The objective of this clinical practice guideline is to provide updated and new evidence-based recommendations for the comprehensive care of persons with diabetes mellitus to clinicians, diabetes-care teams, other health care professionals and stakeholders, and individuals with diabetes and their caregivers.

METHODS

The American Association of Clinical Endocrinology selected a task force of medical experts and staff who updated and assessed clinical questions and recommendations from the prior 2015 version of this guideline and conducted literature searches for relevant scientific papers published from January 1, 2015, through May 15, 2022. Selected studies from results of literature searches composed the evidence base to update 2015 recommendations as well as to develop new recommendations based on review of clinical evidence, current practice, expertise, and consensus, according to established American Association of Clinical Endocrinology protocol for guideline development.

RESULTS

This guideline includes 170 updated and new evidence-based clinical practice recommendations for the comprehensive care of persons with diabetes. Recommendations are divided into four sections: (1) screening, diagnosis, glycemic targets, and glycemic monitoring; (2) comorbidities and complications, including obesity and management with lifestyle, nutrition, and bariatric surgery, hypertension, dyslipidemia, retinopathy, neuropathy, diabetic kidney disease, and cardiovascular disease; (3) management of prediabetes, type 2 diabetes with antihyperglycemic pharmacotherapy and glycemic targets, type 1 diabetes with insulin therapy, hypoglycemia, hospitalized persons, and women with diabetes in pregnancy; (4) education and new topics regarding diabetes and infertility, nutritional supplements, secondary diabetes, social determinants of health, and virtual care, as well as updated recommendations on cancer risk, nonpharmacologic components of pediatric care plans, depression, education and team approach, occupational risk, role of sleep medicine, and vaccinations in persons with diabetes.

CONCLUSIONS

This updated clinical practice guideline provides evidence-based recommendations to assist with person-centered, team-based clinical decision-making to improve the care of persons with diabetes mellitus.

Functional characterization of a novel p.Ser76Thr variant in IGFBP4 that associates with body mass index in American Indians

Insulin-like growth factor binding protein 4 (IGFBP4) is involved in adipogenesis, and IGFBP4 null mice have decreased body fat through decreased PPAR-γ expression. In the current study, we assessed whether variation in the IGFBP4 coding region influences body mass index (BMI) in American Indians who are disproportionately affected by obesity. Whole exome sequence data from a population-based sample of 6779 American Indians with longitudinal measures of BMI were used to identify variation in IGFBP4 that associated with BMI. A novel variant that predicts a p.Ser76Thr in IGFBP4 (Thr-allele frequency = 0.02) was identified which associated with the maximum BMI measured during adulthood (BMI 39.8 kg/m2 for Thr-allele homozygotes combined with heterozygotes vs. 36.2 kg/m2 for Ser-allele homozygotes, β = 6.7% per Thr-allele, p = 8.0 × 10-5, adjusted for age, sex, birth-year and the first five genetic principal components) and the maximum age- and sex-adjusted BMI z-score measured during childhood/adolescence (z-score 0.70 SD for Thr-allele heterozygotes vs. 0.32 SD for Ser-allele homozygotes, β = 0.37 SD per Thr-allele, p = 8.8 × 10-6). In vitro functional studies showed that IGFBP4 with the Thr-allele (BMI-increasing) had a 55% decrease (p = 0.0007) in FOXO-induced transcriptional activity, reflecting increased activation of the PI3K/AKT pathway mediated through increased IGF signaling. Over-expression and knock-down of IGFBP4 in OP9 cells during differentiation showed that IGFBP4 upregulates adipogenesis through PPARγ, CEBPα, AGPAT2 and SREBP1 expression. We propose that this American Indian specific variant in IGFBP4 affects obesity via an increase of IGF signaling.

Periodontitis and implant complications in diabetes

Epidemiologic evidence indicates that periodontitis is more frequent in patients with uncontrolled diabetes mellitus than in healthy controls, suggesting that it could be considered the "sixth complication" of diabetes. Actually, diabetes mellitus and periodontitis are two extraordinarily prevalent chronic diseases that share a number of comorbidities all converging toward an increased risk of cardiovascular disease. Periodontal treatment has recently been shown to have the potential to improve the metabolic control of diabetes, although long-term studies are lacking. Uncontrolled diabetes also seems to affect the response to periodontal treatment, as well as the risk to develop peri-implant diseases. Mechanisms of associations between diabetes mellitus and periodontal disease include the release of advanced glycation end products as a result of hyperglycemia and a range of shared predisposing factors of genetic, microbial, and lifestyle nature. This review discusses the evidence for the risk of periodontal and peri-implant disease in diabetic patients and the potential role of the dental professional in the diabetes-periodontal interface.

Association between maternal shift work during pregnancy child overweight and metabolic outcomes in early childhood

Background

Previous studies found that maternal shift work during pregnancy was associated with many reproductive hazards, including small for gestational age, preterm birth, stillbirth, and neurodevelopmental impairment. Some studies also showed that these children are more likely to become overweight in early childhood. However, the association with metabolic factors, such as insulin resistance and dyslipidemia, was less studied. Hence, we aimed to understand better the relationship between maternal shift work during pregnancy and the risk of childhood overweight and metabolic outcomes. Confounding factors were also discussed, including diet, exercise, and demographical factors.

Methods

We enrolled pregnant women before delivery in the Taiwan Birth Panel Study (TBPS) II conducted between 2010 and 2012, and followed the children of these participants in 2018. The objective of this study is to investigate the influence of prenatal and postnatal factors on infant and early childhood health. During the follow-up in 2018, we checked children's demographic data, obtained blood specimens, and checked their blood sugar, blood insulin, and lipid profiles. Structured questionnaires were used to evaluate demographic data. Multiple linear and logistic regressions were used to examine the associations between maternal shift work during pregnancy and child overweight, metabolic disorders, such as HOMA-IR, and lipid profiles.

Results

In this study, we included 407 mother-children pairs with different work shifts (350 day workers and 57 shift workers), and a sub-population without underweight children was also created (290 day workers and 47 shift workers). Shift work during pregnancy was associated with a higher Homeostasis Model Assessment-Insulin Resistance index (HOMA-IR) and a higher odds ratio for overweight in children born from mothers doing shift work during pregnancy after adjustment. The findings were attenuated when we investigated the effect of shift work before pregnancy.

Conclusion

Our study suggested that maternal shift work during pregnancy was associated with child overweight and insulin resistance in early childhood.

Comprehensive validation of fasting-based and oral glucose tolerance test-based indices of insulin secretion against gold standard measures

INTRODUCTION

With pre-diabetes and diabetes increasingly recognized as heterogeneous conditions, assessment of beta-cell function is gaining clinical importance to identify disease subphenotypes. Our study aims to comprehensively validate all types of surrogate indices based on oral glucose tolerance test (OGTT) and fasting measurements in comparison with gold standard methods.

RESEARCH DESIGN AND METHODS

The hyperglycemic clamp extended with glucagon-like peptide 1 (GLP-1) infusion and intravenous glucose tolerance test (IVGTT), as well as OGTT, was performed in two well-phenotyped cohorts. The gold standard-derived indices were compared with surrogate insulin secretion markers, derived from fasting state and OGTT, using both Pearson's and Spearman's correlation coefficients. The insulin-based and C-peptide-based indices were analyzed separately in different groups of glucose tolerance and the entire cohorts.

RESULTS

The highest correlation coefficients were found for area under curve (AUC) (I_0-30)/AUC (G_0-30), I₃₀/G₃₀, first-phase Stumvoll and Kadowaki model. These indices have high correlation coefficients with measures obtained from both insulin and C-peptide levels from IVGTT and hyperglycemic clamp. AUC (I_0-120)/AUC (G_0-120), BIGTT-AIR_0-60-120, I₃₀/G₃₀, first-phase Stumvoll and AUC (I_0-30)/AUC (G_0-30) demonstrated the strongest association with incretin-stimulated insulin response.

CONCLUSIONS

We have identified glucose-stimulated and GLP-1-stimulated insulin secretion indices, derived from OGTT and fasting state, that have the strongest correlation with gold standard measures and could be potentially used in future researches and clinical practice.

Metformin alleviates long-term high-fructose diet-induced skeletal muscle insulin resistance in rats by regulating purine nucleotide cycle

Nutrient excess caused by excessive fructose intake can lead to insulin resistance and dyslipidemia, which further causes the development of metabolic syndrome. Metformin is a well-known AMPK activator widely used for the treatment of metabolic syndrome, while the mechanism of AMPK activation remains unclear. The present study aimed to investigate the pharmacological effects of metformin on fructose-induced insulin resistance rat, and the potential mechanism underlying AMPK activation in skeletal muscle tissue. Results indicated that metformin significantly ameliorated features of insulin resistance, including body weight, Lee's index, hyperinsulinemia, dyslipidemia, insulin intolerance and pancreatic damage. Moreover, treatment with metformin attenuated the inflammatory response in serum and enhanced the antioxidant capacity in skeletal muscle tissue. The therapeutic effects of metformin on fructose-induced insulin resistance may be related to the activation of AMPK to regulate Nrf2 pathway and mitochondrial abnormality. Additionally, metformin suppressed the expression of adenosine monophosphate deaminase 1 (AMPD1) and up-regulated the expression of adenylosuccinate synthetase (ADSS) in the purine nucleotide cycle (PNC), which facilitated the increase of AMP level and the ratio of AMP/ATP. Therefore, we proposed a novel mechanism that metformin activated AMPK via increasing AMP by regulating the expression of AMPD1 and ADSS in PNC pathway.

Comparison of the Effectiveness of Once-Daily Alogliptin/Metformin and Twice-Daily Anagliptin/Metformin Combination Tablet in a Randomized, Parallel-Group, Open-Label Trial in Japanese Patients with Type 2 Diabetes

INTRODUCTION

The combination tablets of dipeptidyl peptidase-4 (DPP-4) inhibitors and metformin are used for both once-daily and twice-daily agents in Japan. If there is no difference in effectiveness between the once-daily and twice-daily DPP-4 inhibitor/metformin combination tablets, the once-daily agent is advantageous in terms of frequency of administration. The aim of this study was to compare the effectiveness of once-daily alogliptin/metformin combination tablet (alogliptin 25 mg/metformin 500 mg) and twice-daily anagliptin/metformin combination tablet low dose (LD) (anagliptin 100 mg/metformin 250 mg).

METHODS

Forty-eight Japanese patients with type 2 diabetes whose metformin administration of 250 mg twice daily had remained unchanged for at least 8 weeks, except when using DPP-4 inhibitors, glucagon-like peptide-1 receptor agonists, or insulin, were randomized to either the once-daily alogliptin/metformin combination tablet group or the twice-daily anagliptin/metformin combination tablet LD group. The primary endpoint was the difference in glycosylated hemoglobin (HbA1c) levels from baseline to week 12 of administration, whereas the secondary endpoints were fasting blood glucose, body mass index (BMI), and adherence.

RESULTS

Forty-four patients completed the study, and intention-to-treat analyses were performed. The adjusted mean value (standard error) for the change in HbA1c from week 0 to 12, was - 0.75 (0.109)% for the once-daily alogliptin/metformin combination tablet group and - 0.65 (0.109)% for the twice-daily anagliptin/metformin combination tablet LD group, with an intergroup difference of - 0.10% (95% confidence interval, CI - 0.407, 0.215). The upper limit of the bilateral 95% CI was 0.215%, below the 0.40% pre-defined as the non-inferiority margin. Fasting blood glucose, BMI, and adherence were not significantly different between the groups.

CONCLUSIONS

The once-daily alogliptin/metformin combination tablet was non-inferior to the twice-daily anagliptin/metformin combination tablet LD in Japanese patients with type 2 diabetes.

TRIAL REGISTRATION

University Hospital Medical Information Network Clinical Trial Registry (UMIN-CTR) (registration number: UMIN000034951).

Bariatric surgery and the neurohormonal switch: Early insulin resistance recordings after laparoscopic sleeve gastrectomy

Laparoscopic sleeve gastrectomy (LSG) is a bariatric operation with a safe risk profile. It has been proven to successfully reduce weight, decrease insulin resistance (IR), and ameliorate diabetes mellitus. The aim of this study was to determine if there is an early improvement in IR after LSG and its association with weight loss. This was a prospective observational study of 32 patients who underwent LSG at a single center over a 3-year period. Serum insulin and fasting glucose levels were recorded preoperatively, on day 1 postoperatively, and 3 weeks after LSG. IR levels were calculated using the Homeostasis Model Assessment 2 Version 2.23. IR levels were compared along with the overall weight loss, via body mass index. β-cell function was the secondary outcome. IR significantly improved the day after surgery with a statistically significant mean difference of 0.89 units (P = .043) and significantly more so 3 weeks postoperatively, with a mean difference of 4.32 units (P < .0005). β-cell function reduced 3 weeks postoperatively, with a mean difference of 23.95 %β (P = .025), while body mass index significantly reduced, with a mean difference of 4.32 kg/m2 (P < .0005). Early improvement of IR was observed on postoperative day 1 after LSG before any weight loss. This raises the possibility of an undetermined, underlying neurohormonal switch that improves IR. Further investigation is needed to determine this mechanism, as it may lead to an improvement in the medical management of diabetes mellitus.

Epigenetics of type 2 diabetes mellitus and weight change - a tool for precision medicine?

Pioneering studies performed over the past few decades demonstrate links between epigenetics and type 2 diabetes mellitus (T2DM), the metabolic disorder with the most rapidly increasing prevalence in the world. Importantly, these studies identified epigenetic modifications, including altered DNA methylation, in pancreatic islets, adipose tissue, skeletal muscle and the liver from individuals with T2DM. As non-genetic factors that affect the risk of T2DM, such as obesity, unhealthy diet, physical inactivity, ageing and the intrauterine environment, have been associated with epigenetic modifications in healthy individuals, epigenetics probably also contributes to T2DM development. In addition, genetic factors associated with T2DM and obesity affect the epigenome in human tissues. Notably, causal mediation analyses found DNA methylation to be a potential mediator of genetic associations with metabolic traits and disease. In the past few years, translational studies have identified blood-based epigenetic markers that might be further developed and used for precision medicine to help patients with T2DM receive optimal therapy and to identify patients at risk of complications. This Review focuses on epigenetic mechanisms in the development of T2DM and the regulation of body weight in humans, with a special focus on precision medicine.

Relationships among phthalate exposure, oxidative stress, and insulin resistance in young military soldiers: A cumulative risk assessment and mediation approach

BACKGROUND

Epidemiological studies concerning whether oxidative stress mediates phthalate exposure-insulin resistance (IR) associations in young adults are limited. Therefore, we investigated this potential mediation by using a cumulative risk approach involving daily intake (DI) and a hazard index (HI_RfD).

METHODS

The participants were 391 Taiwanese military personnel. This study measured their IR (as homeostatic model assessment of estimated IR [HOMA-IR]), levels of oxidative stress biomarkers (8-hydroxy-2-deoxyguanosine, 8-nitroguanine, 8-iso-prostaglandin F2α, and N-acetyl-S-[tetrahydro-5-hydroxy-2-pentyl-3-furanyl]-L-cysteine [HNE-MA]), the sum of these four biomarkers (ΣOS), and urinary phthalate metabolite concentrations. The HI_RfD was estimated on the basis of urinary levels of phthalate metabolite, and the DI of five phthalates was determined: dimethyl phthalate, benzyl butyl phthalate (BBzP), diethyl phthalate, dibutyl phthalate (DBP), and di (2-ethylhexyl) phthalate (DEHP). Logistic regression models were employed to explore associations among DI, HI_RfD, oxidative stress biomarkers, and HOMA-IR values. The role played by oxidative stress in the phthalate exposure-HOMA-IR association was determined using mediation analysis.

RESULTS

We discovered positive associations between high DI of DBP, BBzP, and DEHP; high HI_RfD; and high ΣOS. High ΣOS and HNE-MA were associated with a higher likelihood of a high HOMA-IR value. Mediation analysis indicated that high ΣOS and HNE-MA were significant mediators of the associations between phthalates and IR.

CONCLUSION

Oxidative stress may partially mediate the phthalate-IR relationship in young adults.

Feasibility of home-based tracking of insulin resistance from vascular stiffness estimated from the photoplethysmographic finger pulse waveform

In this study, we explored the utility of post-prandial vascular stiffness as a surrogate measure for the estimation of insulin resistance (IR), which is a pre-diabetic condition. A cohort of 51 healthy young adults of varying Body mass index values (BMI) were studied by fasting plasma values of insulin and glucose; fasting and post-meal finger photoplethysmography (PPG), and electrocardiogram (ECG). Insulin resistance was estimated by Homeostatic model assessment-Insulin resistance 2 (HOMA-IR2) using fasting plasma insulin and glucose. Vascular stiffness was estimated by reciprocal of pulse arrival time (rPAT) from ECG and finger PPG at five time points from fasting to 2-hours post oral glucose ingestion. We examined if insulin resistance is correlated with meal induced vascular stiffness changes supporting the feasibility of using finger PPG for the estimation of insulin resistance. HOMA-IR2 was found to be positively correlated with early rise (0- to 30- minutes post meal) and delayed fall (30- to 120-minutes) of rPAT. Correlation persisted even after the effect of BMI has been partialled out in sub-group analysis. We conclude that finger PPG based pulse waveform and single lead ECG has the potential to be used as a non-invasive method for the assessment of insulin resistance. As both signals viz., ECG and PPG can be easily acquired using wearable and other low-cost sensing systems, the present study can serve as a pointer for the development of accessible methods of monitoring and longitudinal tracking of insulin resistance in health and pathophysiological states.

Does Insufficient Sleep Increase the Risk of Developing Insulin Resistance: A Systematic Review

It has been recommended that adults sleep a minimum of seven hours of sleep every night to maintain holistic health and well-being. A considerable fraction of the adult population suffers from sleep deprivation and related disorders. The stress of modern-day living may be the cause of this curtailment of sleep duration. The primary purpose of this study was to investigate the effects of reduced sleep on the development of insulin resistance and explore the possible mechanisms linking the two. We utilized databases like such as PubMed, PubMed Central (PMC), and Medical Literature Analysis and Retrieval System Online (MEDLINE) to systematically screen papers using keywords and Medical Subject Heading (MeSH) terms. A few articles were also retrieved from Cochrane Library. We applied inclusion/exclusion criteria after screening papers via title and abstracts. A quality appraisal check was doneperformed, and ten 10 related studies were strictly reviewed.

Short sleep duration was significantly associated with insulin resistance. Inflammatory markers such as C-reactive protein (CRP) and serum amyloid A (SAA), biomarkers such as glucagon-like peptide-1 (GLP-1), and circadian misalignment may play a significant role in the pathogenesis of this association. To prevent metabolic complications such as type- 2 diabetes, adequate sleep (more than seven hours per night) is required in the adult population. The causal relationship between sleep deprivation and insulin resistance is multifactorial, and further studies are warranted to understand these mechanisms better.

A Retrospective Study of the Relationship Between the Triglyceride Glucose Index and Myocardial Revascularization for New-Onset Acute Coronary Syndromes

Background

This study explored the relationship between the TyG index/serum uric acid (SUA) panel and myocardial revascularization (MRT) for new-onset acute coronary syndromes (ACS).

Methods

Between January 2011 and July 2020, 13,271 new-onset ACS patients were enrolled. The logistic regression models and the odds ratios (ORs) were used to quantify the risk of TyG index/SUA and MRT. Then, interaction analyses of TyG index and SUA on MRT were applied.

Results

Elevated TyG index was positively associated higher risks of MRT. However, SUA levels were negatively associated with MRT. Compared with those in the lowest quartile, the risk of MRT increased gradually among patients in Q1 of the SUA category (OR = 1.03, 1.11, and 1.28 for Q2, Q3, and Q4 of TyG index, respectively), Q2 of the SUA category (OR = 1.41, 1.68, and 2.18 for Q2, Q3, and Q4 of TyG index, respectively), Q3 of the SUA category (OR = 1.05, 1.45, and 1.45 for Q2, Q3, and Q4 of TyG index, respectively), and Q4 of the SUA category (OR = 1.20, 1.29, and 1.46 for Q2, Q3, and Q4 of TyG index, respectively). This pattern was observed in both male and female, as well as patients without type 2 diabetes mellitus.

Conclusion

Patients with a higher TyG index have a higher proportion of MRT in new-onset ACS. This result also applies to patients with different levels of SUA during new-onset ACS.

A missense variant Arg611Cys in LIPE which encodes hormone sensitive lipase decreases lipolysis and increases risk of type 2 diabetes in American Indians

AIMS

Hormone sensitive lipase (HSL), encoded by the LIPE gene, is involved in lipolysis. Based on prior animal and human studies, LIPE was analysed as a candidate gene for the development of type 2 diabetes (T2D) in a community-based sample of American Indians.

MATERIALS AND METHODS

Whole-exome sequence data from 6782 participants with longitudinal clinical measures were used to identify variation in LIPE.

RESULTS

Amongst the 16 missense variants identified, an Arg611Cys variant (rs34052647; Cys-allele frequency = 0.087) significantly associated with T2D (OR [95% CI] = 1.38 [1.17-1.64], p = 0.0002, adjusted for age, sex, birth year, and the first five genetic principal components) and an earlier onset age of T2D (HR = 1.22 [1.09-1.36], p = 0.0005). This variant was further analysed for quantitative traits related to T2D. Amongst non-diabetic American Indians, those with the T2D risk Cys-allele had increased insulin levels during an oral glucose tolerance test (0.07 SD per Cys-allele, p = 0.04) and a mixed meal test (0.08 log₁₀ µU/ml per Cys-allele, p = 0.003), and had increased lipid oxidation rates post-absorptively and during insulin infusion (0.07 mg [kg estimated metabolic body size {EMBS}]^-1  min^-1 per Cys-allele for both, p = 0.01 and 0.009, respectively), compared to individuals with the non-risk Arg-allele. In vitro functional studies showed that cells expressing the Cys-allele had a 17.2% decrease in lipolysis under isoproterenol stimulation (p = 0.03) and a 21.3% decrease in lipase enzyme activity measured by using p-nitrophenyl butyrate as a substrate (p = 0.04) compared to the Arg-allele.

CONCLUSION

The Arg611Cys variant causes a modest impairment in lipolysis, thereby affecting glucose homoeostasis and risk of T2D.

Trends in spontaneous physical activity and energy expenditure among adults in a respiratory chamber, 1985 to 2005

OBJECTIVE

Fidgeting, a type of spontaneous physical activity (SPA), has substantial thermogenic potential. This research aims to examine secular trends in SPA and energy expenditure (EE) inside a respiratory chamber.

METHODS

From 1985 to 2005, healthy adults (n = 678; mean age: 28.8 years; men: 60%; 522 Indigenous American, 129 White, and 27 Black) had a 24-hour stay in the respiratory chamber equipped with radar sensors. Body composition, glucose tolerance, fasting insulin, insulin action (hyperinsulinemic-euglycemic clamp), and insulin secretion (intravenous glucose tolerance test) were measured as covariates.

RESULTS

SPA, adjusted for age, sex, race, and body composition, declined (r = -0.30, p < 0.0001), with a concomitant rise in the energy cost of SPA (r = 0.30, p < 0.0001). The 24-hour EE adjusted for covariates increased (r = 0.31, p < 0.0001), which was reflected in increases in EE during sleep (r = 0.18, p < 0.0001) and during the awake, fed condition (r = 0.28, p < 0.0001). The secular trends in SPA or 24-hour EE were unchanged with adjustment for measures related to glucose metabolism.

CONCLUSIONS

Secular trend analyses showed a decline in fidgeting. However, this decline in SPA was partially counterbalanced by an increase in energy cost of this activity and a rise in EE. Nevertheless, our results support public health efforts to promote small but sustained changes in these behaviors.

Potential Mechanisms for How Long-Term Physical Activity May Reduce Insulin Resistance

Insulin became available for the treatment of patients with diabetes 100 years ago, and soon thereafter it became evident that the biological response to its actions differed markedly between individuals. This prompted extensive research into insulin action and resistance (IR), resulting in the universally agreed fact that IR is a core finding in patients with type 2 diabetes mellitus (T2DM). T2DM is the most prevalent form of diabetes, reaching epidemic proportions worldwide. Physical activity (PA) has the potential of improving IR and is, therefore, a cornerstone in the prevention and treatment of T2DM. Whereas most research has focused on the acute effects of PA, less is known about the effects of long-term PA on IR. Here, we describe a model of potential mechanisms behind reduced IR after long-term PA to guide further mechanistic investigations and to tailor PA interventions in the therapy of T2DM. The development of such interventions requires knowledge of normal glucose metabolism, and we briefly summarize an integrated physiological perspective on IR. We then describe the effects of long-term PA on signaling molecules involved in cellular responses to insulin, tissue-specific functions, and whole-body IR.

Hormonal and metabolic profiles of obese and nonobese type 2 diabetes patients: implications of plasma insulin, ghrelin, and vitamin D levels

Type 2 diabetes (T2D) is associated with obesity whereas loss of weight is a feature of the disease; however, the two states are not mutually exclusive. Obesity is linked with changes in hormonal activity and overall body metabolism.

The pathophysiology of glucose intolerance in newly diagnosed, untreated T2DM

AIMS

The two predominant pathophysiological defects resulting in glucose intolerance are beta-cell dysfunction and insulin insensitivity. This study aimed to re-examine beta-cell function and insulin sensitivity across a continuum from normal glucose tolerance (NGT) to early type 2 diabetes (T2DM) employing highly specific insulin, C-peptide and intact proinsulin assays.

MATERIALS AND METHODS

A total of 104 persons with NGT, 85 with impaired glucose tolerance (IGT) and 554 with newly diagnosed T2DM were investigated. Following an overnight fast, all underwent a 4-h standardised mixed meal tolerance test (MTT), and on a second day, a sub-group underwent a frequently sampled insulin-modified intravenous glucose tolerance test (FSIVGTT) over a 3-h period. The participants were stratified according to fasting glucose and BMI for analysis.

RESULTS

The MTT revealed that increasing FPG was accompanied by progressively elevated and delayed postprandial glucose peaks. In parallel, following an initial compensatory increase in fasting and postprandial insulin responses there followed a progressive demise in overall beta-cell secretory capacity. FSIVGTT demonstrated a major reduction in the early insulin response to IV glucose in persons with IGT accompanied by a dramatic fall in insulin sensitivity. Beyond pre-diabetes, ever-increasing fasting and postprandial hyperglycaemia resulted predominantly from a progressively decreasing beta-cell secretory function.

CONCLUSION

This study utilising improved assay technology re-affirms that beta-cell dysfunction is evident throughout the spectrum of glucose intolerance, whereas the predominant fall in insulin sensitivity occurs early in its evolution.

Systems-level analysis of insulin action in mouse strains provides insight into tissue- and pathway-specific interactions that drive insulin resistance

Skeletal muscle and adipose tissue insulin resistance are major drivers of metabolic disease. To uncover pathways involved in insulin resistance, specifically in these tissues, we leveraged the metabolic diversity of different dietary exposures and discrete inbred mouse strains. This revealed that muscle insulin resistance was driven by gene-by-environment interactions and was strongly correlated with hyperinsulinemia and decreased levels of ten key glycolytic enzymes. Remarkably, there was no relationship between muscle and adipose tissue insulin action. Adipocyte size profoundly varied across strains and diets, and this was strongly correlated with adipose tissue insulin resistance. The A/J strain, in particular, exhibited marked adipocyte insulin resistance and hypertrophy despite robust muscle insulin responsiveness, challenging the role of adipocyte hypertrophy per se in systemic insulin resistance. These data demonstrate that muscle and adipose tissue insulin resistance can occur independently and underscore the need for tissue-specific interrogation to understand metabolic disease.

Unraveling Gut Microbiota Signatures Associated with PPARD and PARGC1A Genetic Polymorphisms in a Healthy Population

Recent studies have revealed the importance of the gut microbiota in the regulation of metabolic phenotypes of highly prevalent metabolic diseases such as obesity, type II diabetes mellitus (T2DM) and cardiovascular disease. Peroxisome proliferator-activated receptors (PPARs) are a family of ligand-activated nuclear receptors that interact with PPAR-γ co-activator-1α (PPARGC1A) to regulate lipid and glucose metabolism. Genetic polymorphisms in PPARD (rs 2267668; A/G) and PPARGC1A (rs 8192678; G/A) are linked to T2DM. We studied the association between the single-nucleotide polymorphisms (SNPs) rs 2267668 and rs 8192678 and microbiota signatures and their relation to predicted metagenome functions, with the aim of determining possible microbial markers in a healthy population. Body composition, physical exercise and diet were characterized as potential confounders. Microbiota analysis of subjects with PPARGC1A (rs 8192678) and PPARD (rs 2267668) SNPs revealed certain taxa associated with the development of insulin resistance and T2DM. Kyoto encyclopedia of gene and genomes analysis of metabolic pathways predicted from metagenomes highlighted an overrepresentation of ABC sugar transporters for the PPARGC1A (rs 8192678) SNP. Our findings suggest an association between sugar metabolism and the PPARGC1A rs 8192678 (G/A) genotype and support the notion of specific microbiota signatures as factors related to the onset of T2DM.

Characterizing skeletal muscle dysfunction in women with polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is the most common endocrine condition affecting women. It has traditionally been viewed as a primarily reproductive disorder; however, it is increasingly recognized as a lifelong metabolic disease. Women with PCOS are at increased risk of insulin resistance (IR), type 2 diabetes mellitus, non-alcoholic fatty liver disease and cardiovascular disease. Although not currently a diagnostic criterion, IR is a cardinal pathophysiological feature and highly prevalent in women with PCOS. Androgens play a bidirectional role in the pathogenesis of IR, and there is a complex interplay between IR and androgen excess in women with PCOS. Skeletal muscle has a key role in maintaining metabolic homeostasis and is also a metabolic target organ of androgen action. Skeletal muscle is the organ responsible for the majority of insulin-mediated glucose disposal. There is growing interest in the relationship between skeletal muscle, androgen excess and mitochondrial dysfunction in the pathogenesis of metabolic disease in PCOS. Molecular mechanisms underpinning defects in skeletal muscle dysfunction in PCOS remain to be elucidated, but may represent promising targets for future therapeutic intervention. In this review, we aim to explore the role of skeletal muscle in metabolism, focusing particularly on perturbations in skeletal muscle specific to PCOS as observed in recent molecular and in vivo human studies. We review the possible role of androgens in the pathophysiology of skeletal muscle abnormalities in PCOS, and identify knowledge gaps, areas for future research and potential therapeutic implications. Despite increasing interest in the area of skeletal muscle dysfunction in women with PCOS, significant challenges and unanswered questions remain, and going forward, novel innovative approaches will be required to dissect the underlying mechanisms.

Differences in protein expression, at the basal state and at 2 h of insulin infusion, in muscle biopsies from healthy Arab men with high or low insulin sensitivity measured by hyperinsulinemic euglycemic clamp

BACKGROUND

Skeletal muscle is the main site for insulin-dependent glucose disposal. The hyperinsulinemic euglycemic clamp (HIEC) is the gold standard for the assessment of insulin sensitivity (IS). We have previously shown that insulin sensitivity, measured by HIEC, varied widely among a group of 60 young healthy men with normoglycemia. The aim of this study was to correlate the proteomic profile of skeletal muscles to insulin sensitivity.

METHODS

Muscle biopsies from 16 subjects having the highest (M ≥ 13; n = 8, HIS) and lowest (M ¾ 6, n = 8, LIS) IS were obtained at baseline and during insulin infusion after stabilization of the blood glucose level and glucose infusion rate at the end of the HIEC. The samples were processed using a quantitative proteomic analysis approach.

RESULTS

At baseline, 924 proteins were identified in the HIS and LIS groups. Among the 924 proteins detected in both groups, three were suppressed and three were increased significantly in the LIS subjects compared with the HIS subjects. Following insulin infusion, 835 proteins were detected in both groups. Among the 835 proteins, two showed differential responsiveness to insulin; ATP5F1 protein was decreased, and MYLK2 was higher in the LIS group compared with that in the HIS group. Our data suggest that alteration in mitochondrial proteins and an increased number of proteins involved in fast-twitch fiber correlate to insulin sensitivity in healthy young Arab men.

CONCLUSIONS

These results suggest a change in a small number of differentially expressed proteins. A possible reason for this small change could be our study cohorts representing a homogeneous and healthy population. Additionally, we show differences in protein levels from skeletal muscle in low and high insulin sensitivity groups. Therefore, these differences may represent early events for the development of insulin resistance, pre-diabetes, and type 2 diabetes.

Aldo-ketoreductase 1c19 ablation does not affect insulin secretion in murine islets

Beta cell failure is a critical feature of diabetes. It includes defects of insulin production, secretion, and altered numbers of hormone-producing cells. In previous work, we have shown that beta cell failure is mechanistically linked to loss of Foxo1 function. This loss of function likely results from increased Foxo1 protein degradation, due to hyperacetylation of Foxo1 from increased nutrient turnover. To understand the mechanisms of Foxo1-related beta cell failure, we performed genome-wide analyses of its target genes, and identified putative mediators of sub-phenotypes of cellular dysfunction. Chromatin immunoprecipitation analyses demonstrated a striking pattern of Foxo1 binding to the promoters of a cluster of aldo-ketoreductases on chromosome 13: Akr1c12, Akr1c13, Akr1c19. Of these, Akr1c19 has been reported as a marker of Pdx1-positive endodermal progenitor cells. Here we show that Akr1c19 expression is dramatically decreased in db/db islets. Thus, we investigated whether Akr1c19 is involved in beta cell function. We performed gain- and loss-of-function experiments in cultured beta cells and generated Akr1c19 knockout mice. We show that Foxo1 and HNF1a cooperatively regulate Akr1c19 expression. Nonetheless, functional characterization of Akr1c19 both using islets and knockout mice did not reveal abnormalities on glucose homeostasis. We conclude that reduced expression of Akr1c19 is not sufficient to affect islet function.

Novel Laboratory Index, Based on Fasting Blood Parameters, Accurately Reflects Insulin Sensitivity

CONTEXT

Simple and reliable measurement of insulin sensitivity may be important for the prevention of insulin-resistance-related diseases. Surrogate indices of insulin sensitivity are of limited utility in population without signs of metabolic syndrome.

OBJECTIVE

The aim of our study was to provide simple and accurate index of insulin sensitivity.

DESIGN

The study group comprised 150 young healthy participants. Hyperinsulinemic-euglycemic clamp was performed. Regression models with different laboratory parameters were constructed. Validation cohort 1 comprised independent group of 110 subjects, including individuals with prediabetes and newly diagnosed type 2 diabetes. Validation cohort 2 comprised 38 obese subjects before and after diet-induced weight loss. Validation cohort 3 comprised 60 nondiabetic subjects from an independent center.

RESULTS

The supervised principal component model established optimal set of variables correlated with insulin sensitivity. This model (Fasting Laboratory Assessment of Insulin Sensitivity [FLAIS]) used red blood cell count, alanine aminotransferase activity, serum C-peptide, SHBG, IGF-binding protein 1, and adiponectin concentrations. FLAIS exhibited strong correlation with clamp-derived insulin sensitivity. The sensitivity of the model was 90% and the specificity was 68%. In validation cohort 1, differences in FLAIS among the groups paralleled those observed with the clamp, with the lowest values in prediabetes and diabetes. In validation cohort 2, FLAIS reflected the change in insulin sensitivity after weight loss. The main findings were confirmed in validation cohort 3.

CONCLUSION

We provide simple and accurate method of assessing insulin sensitivity, which allows to identify insulin resistance even in the population without overt metabolic disturbances.

Associations Between the Metabolic Score for Insulin Resistance Index and the Risk of Type 2 Diabetes Mellitus Among Non-Obese Adults: Insights from a Population-Based Cohort Study

Purpose

The metabolic score for insulin resistance (METS-IR) index is an emerging surrogate predictor of type 2 diabetes mellitus (T2DM). This study aimed to evaluate the association between the METS-IR index and the risk of T2DM in non-obese Japanese adults.

Methods

A total of 12,290 non-obese participants were selected from the NAGALA prospective cohort study conducted from 2004 to 2015. Cox proportional hazards models were used to assess the association between the baseline METS-IR index and risk of T2DM. Generalized additive models were used to identify nonlinear relationships. In addition, we performed subgroup analyses and interaction tests. Results were expressed as hazard ratios (HRs) and 95% confidence intervals (CIs).

Results

During a median follow-up of 2050 days, 176 (1.43%) incident T2DM occurred. The fully adjusted HR (95% CI) for the incidence of T2DM in non-obese adults was 1.17 (HR=1.17, 95% CI: 1.09–1.27, P<0.001) for every 1-unit increase in the METS-IR index. The risk of developing T2DM increased with the quartile of change in the METS-IR index, after adjustment for multiple potential confounding, the HRs for the Q4 group versus the Q1 group was 4.01 (95% CI, 1.39–11.57). Generalized additive models also showed a cumulative increase in the risk of T2DM with increasing the METS-IR index. Time-dependent receiver operating curve suggested helpful discriminative power of the METS-IR index for T2DM. The C-statistics by the clinical risk factors significantly improve with the addition of the METS-IR index (from 0.862 to 0.875, P = 0.035); the discriminatory power and risk reclassification also appeared to be substantially better, with the category-free NRI of 0.216, and the IDI of 0.011.

Conclusion

The METS-IR index was a significant and independent predictor for future T2DM development in non-obese adults. The METS-IR index may have clinical significance in identifying groups at high risk of T2DM.