Insulinogenic indices from insulin and C-peptide: comparison of beta-cell function from OGTT and IVGTT

Subphenotype-Dependent Benefits of Bariatric Surgery for Individuals at Risk for Type 2 Diabetes

OBJECTIVE

Bariatric surgery is an effective treatment option for individuals with obesity and type 2 diabetes (T2D). However, whether outcomes in subtypes of individuals at risk for T2D and/or comorbidities (Tübingen Clusters) differ, is unknown. Of these, cluster 5 (C5) and cluster 6 (C6) are high-risk clusters for developing T2D and/or comorbidities, while cluster 4 (C4) is a low-risk cluster. We investigated bariatric surgery outcomes, hypothesizing that high-risk clusters benefit most due to great potential for metabolic improvement.

RESEARCH DESIGN AND METHODS

We allocated participants without T2D but at risk for T2D, defined by elevated BMI, to the Tübingen Clusters. Participants had normal glucose regulation or prediabetes according to American Diabetes Association criteria. Two cohorts underwent bariatric surgery: a discovery (Lille, France) and a replication cohort (Rome, Italy). A control cohort (Tübingen, Germany) received behavioral modification counseling. Main outcomes included alteration of glucose regulation parameters and prediabetes remission.

RESULTS

In the discovery cohort, 15.0% of participants (n = 121) were allocated to C4, 22.3% (n = 180) to C5, and 62.4% (n = 503) to C6. Relative body weight loss was similar among all clusters; however, reduction of insulin resistance and improvement of β-cell function were strongest in C5. Prediabetes remission rate was lowest in low-risk C4 and highest in high-risk C5. Individuals from high-risk clusters changed to low-risk clusters in both bariatric surgery cohorts but not in the control cohort.

CONCLUSIONS

Participants in C5 had the highest benefit from bariatric surgery in terms of improvement in insulin resistance, β-cell function, and prediabetes remission. This novel classification might help identify individuals who will benefit specifically from bariatric surgery.

Predictors of diabetes remission after bariatric surgery in patients with type 2 diabetes mellitus duration ≥ 10 years: A retrospective cohort study

OBJECTIVE

Patients with type 2 diabetes mellitus (T2DM) duration ≥ 10 years often have significant β-cell failure. This study aimed to explore predictors of diabetes remission after bariatric surgery in these patients.

METHODS

Patients with T2DM duration ≥ 10 years who underwent bariatric surgery were retrospective included and followed up. Remission of diabetes was defined as an HbA1c < 6.5 % (48 mmol/mol) at least 3 months after the discontinuation of hypoglycemic drugs. An intravenous glucose tolerance test (IVGTT) was performed in patients with diabetes remission.

RESULTS

203 patients with T2DM duration ≥ 10 years were included, 59.6 % were treated with insulin before bariatric surgery. One-, two- and three-year post-surgery remission rates were 65.6 %, 53.8 % and 41.9 %, respectively (∼10 % decrease/year). Cox regression analysis revealed that the odds of remission at one-year post-bariatric surgery were most strongly associated with β-cell function (HR 1.20, 95 % CI 1.03-1.40) and percentage of total weight loss (%TWL) (HR 1.04, 95 % CI 1.01-1.07). The first-phase insulin secretion peak was approximately 5-8 folds of the fasting insulin level in 50 patients with diabetes remission.

CONCLUSIONS

%TWL and β-cell function are significantly associated with diabetes remission after bariatric surgery in long-duration T2DM patients, with restored first-phase insulin secretion still observed.

Menopause and Diabetes Risk Along with Trajectory of β-Cell Function and Insulin Sensitivity: A Community-Based Cohort Study

BACKGROUND

The relationship between menopause and diabetes risk is unclear, with some studies indicating a weak association. This study examined changes in diabetes risk, β-cell function, and insulin sensitivity in relation to menopause.

METHODS

In this community-based cohort study, data from 6684 visits to 1224 women over a 16-year follow-up were analyzed. Diabetes risk changes were assessed in relation to the different menopausal phases: premenopausal (≥3 years before menopause), perimenopausal (2 years before to 1 year after menopause), and postmenopausal (≥2 years after menopause). Changes in β-cell function and insulin sensitivity indices were tracked, and their relationship with diabetes risk was assessed. Generalized estimating equations and linear mixed models were used, adjusting for covariates including age at menopause and obesity.

RESULTS

Diabetes incidence was 18.6% among participants. The odds ratio (OR) of diabetes increased by 1.03 times annually during the premenopausal period (OR 1.03; 95% CI 1.02-1.04) and decreased during the postmenopausal period (OR 0.96; 95% CI 0.95-0.97). The incident diabetes groups showed a decline in insulin sensitivity and β-cell function, resulting in a decrease in the disposition indices over time. A large change in insulin sensitivity, especially during the period immediately before the onset of diabetes, increased the risk of diabetes (OR 1.88; 95% CI 1.33-2.67).

CONCLUSIONS

This study indicates an increased diabetes risk during the premenopausal periods, compared with that in the postmenopausal period, independent of age at menopause and obesity. Additionally, a decrease in insulin sensitivity followed by a subsequent decrease in β-cell function depending on the time of onset was related to the risk of diabetes. These findings enhance the understanding of diabetes risk and associated changes in insulin indices in relation to menopause, emphasizing the importance of health management and diabetes prevention for women in menopausal transition.

Early prediction of gestational diabetes mellitus: the role of the pregnancy-specific triglycerides-glucose index and other fasting parameters in combination with dynamic testing

The identification of mothers at risk for gestational diabetes mellitus (GDM) at start of pregnancy may be beneficial to improve perinatal outcomes. This study aims evaluating the predictive performance of fasting and dynamic indices of glucose metabolism at first trimester and their association with later GDM development. A cohort of 198 women received detailed metabolic assessment at median gestational age (13 weeks) including 75-g oral glucose tolerance test (OGTT) with assessment of glucose, insulin and C-peptide, and biochemical markers (including triglycerides) to calculate different indices of insulin sensitivity either at fasting and in the OGTT dynamic conditions. Moreover, parameters of β-cell function were assessed. A second OGTT was performed between 24 and 28 gestational weeks (GW) to identify women with GDM. We found that 28 women developed GDM, and, in univariable analysis, this was fairly predicted by several first trimester indices, both at fasting and in dynamic conditions. However, fasting indices containing maternal triglycerides showed better accuracy as compared to traditional indices (even the dynamic ones). In multivariable analysis, the best predictive model of GDM development included fasting and OGTT glucose values, HbA1c, and an insulin sensitivity marker that includes triglycerides (e.g. the improved triglyceride-glucose index, TyGIS). β-Cell function was not included in such predictive model, but at 24-28 GW it showed remarkable impairment in women with GDM. In conclusion, both fasting and dynamic parameters of glucose homeostasis at early pregnancy showed fair predictive accuracy for later GDM, with TyGIS showing excellent performance. β-Cell dysfunction role needs being further elucidated.

Effect of insulin sensitivity, insulin secretion, and beta cell function on the remission of type 2 diabetes: A post hoc analysis of the IDEATE trial

AIMS

To compare the probability of achieving diabetes remission in individuals with different phenotypes of insulin sensitivity, insulin secretion, and beta cell function and further detect the effects of diet, exercise, and lifestyle education intervention on these indexes.

METHODS

Three-hundred and one participants who had glycated haemoglobin (HbA1c) data at baseline and after intervention were included for this post hoc analysis. We used the multi-way analysis of variance to assess the differences between the diabetes remission and non-remission groups or between intervention groups in changes of the indexes of insulin sensitivity, insulin secretion, and beta cell function. Furthermore, logistic regression analysis was used to identify the association between the diabetes remission and baseline and change of each insulin index.

RESULTS

Participants with a higher disposition index (DI) or higher adaptation index at baseline were more likely to achieve diabetes remission. The diabetes remission group had a significantly greater increase in AUCc-pep0-30/AUCgluc0-30, DI, and adaptation index compared with the non-remission group, while there were no between-group differences in indexes of insulin sensitivity. Participants with greater increases in insulin secretion and beta cell function were more likely to achieve diabetes remission. Indexes of beta cell function improved in all intervention groups, while the diet intervention induced significant improvement compared with lifestyle education.

CONCLUSIONS

These findings supported the importance of aggressively implementing intensive lifestyle interventions for individuals with type 2 diabetes at an early stage of the disease, when beta cell function was not yet significantly impaired, to promote achieving diabetes remission.

Isolating the acute metabolic effects of carbohydrate restriction on postprandial metabolism with or without energy restriction: a crossover study

Low-carbohydrate diets and intermittent energy restriction may offer metabolic advantages in fuel utilisation, that are independent of weight loss. The underlying mechanisms for these effects are unclear but may involve extensions of the catabolic phase and/or attenuation of insulin secretion. To address this gap, we aimed to investigate the independent acute metabolic effect of carbohydrate restriction at varying energy levels. Twelve, (six female) healthy overweight/obese participants (27.3 ± 1.8 years; 25.2 ± 1.6 kg/m2) completed this three-way study. Volunteers followed three diets for one day (36 h, covering the intervention day and overnight fasting), separated by 5-day washout: a normal carbohydrate, energy-balanced diet (nEB, 55% CHO), a low-carbohydrate, energy-balanced diet (LCEB, 50 g/day CHO), and a low-carbohydrate, energy-restricted diet (LC25, 50 g/day CHO with 75% energy restriction). Fasting and serial postprandial (360 min) measurements to a mixed test meal were collected the following morning. Additionally, subjective appetite responses and two-day subsequent ad libitum food intake was assessed. Both low-carbohydrate with and without energy restriction diets induced comparable decrease in triacylglycerol iAUC (p = 0.02, p = 0.04, respectively), and respiratory quotient (both p < 0.01) along with increase in non-esterified fatty acids (both p < 0.01) and 3-hydroxybutyrate (p = 0.001, p = 0.01, respectively) levels. Compared to a non-restricted carbohydrate, energy-balanced diet, postprandial glucose levels significantly increased in the LCEB arm (p = 0.024) and showed a rising trend in the LC25 arm (p = 0.07). Neither insulin responses nor resting, and diet-induced thermogenesis were significantly altered by variations in energy or carbohydrate content. These findings demonstrate that carbohydrate restriction, without altering energy intake, can elicit effects similar to those observed in short-term fasting. As such we propose a strategy of repeated carbohydrate restriction cycles alone may be an emerging alternative approach for the enhancement of cardiometabolic health, warranting further investigation.

1-Hour Postload Glucose: Early Screening for High Risk of Type 2 Diabetes in Koreans With Normal Fasting Glucose

CONTEXT

With rising the prevalence of type 2 diabetes mellitus (T2DM) and prediabetes, the importance of 1-hour postload plasma glucose (1-h PG) for early hyperglycemia screening is emphasized.

OBJECTIVE

This study investigates the utility of 1-h PG in predicting T2DM in adults with normal fasting plasma glucose levels.

METHODS

A total of 7504 participants were categorized into 3 groups: normal glucose tolerance (NGT) with 1-h PG < 155 mg/dL, NGT with 1-h PG ≥ 155 mg/dL, and impaired glucose tolerance (IGT). Insulin sensitivity and secretion indices were compared between groups at baseline, and T2DM incidence was analyzed using Cox proportional hazards models. The predictive abilities of 1-h PG and 2-hour postload plasma glucose (2-h PG) were assessed with receiver operating characteristic analysis.

RESULTS

At baseline, the composite insulin sensitivity index in the NGT and 1-h PG ≥ 155 mg/dL group was similarly reduced as in the IGT group (P = .076). Over a mean follow-up of 7.4 years, T2DM developed in 960 patients (12.8%). The highest risk was in the IGT group (hazard ratio, 5.47), followed by the NGT and 1-h PG ≥ 155 mg/dL group (hazard ratio, 2.74), compared to the NGT and 1-h PG < 155 mg/dL group. The 1-h PG level had a higher area under the curve (0.772) than other glycemic parameters, including 2-h PG.

CONCLUSIONS

Even with normal fasting plasma glucose, a 1-h PG ≥ 155 mg/dL indicates lower insulin sensitivity similar to IGT and increased T2DM risk, making it a more effective early screening tool than 2-h PG.

Metabolic, genetic and immunological features of relatives of type 1 diabetes patients with elevated insulin resistance

PURPOSE

Insulin resistance plays a pivotal role in the preclinical stages of type 1 diabetes (T1D).

OBJECTIVE

This study aims at exploring the genetic, metabolic, and immunological features associated with insulin resistance among individuals at risk of developing T1D.

METHODS

We retrospectively selected relatives of individuals with T1D from participants in the TrialNet Pathway to Prevention study. They were categorized into two groups: high-H (n = 27) and low-H (n = 30), based on the upper and lower quartiles of insulin resistance assessed using the Homeostatic Model Assessment of Insulin Resistance (HOMA-IR). Genetic predisposition was determined using the T1D Genetic Risk Score 1 (GRS1). Additionally, glucose control was evaluated through an oral glucose tolerance test and levels of metabolic hormones and inflammatory cytokines were measured in the serum. Flow cytometry analysis was employed to assess frequency and phenotype of islet-specific CD8 T cells.

RESULTS

While GRS1 were similar between the low-H and high-H groups, high-H individuals displayed a distinct metabolic profile, characterized by compensatory hyperinsulinemia, even while maintaining normoglycemia. Circulating cytokine levels were similar between the two groups. However, immune profiling revealed a central memory and activated profile of GAD65-specific CD8 T cells, along with an increased frequency of insulin-specific CD8 T cells in high-H individuals. The enrichment in insulin-specific CD8 T cells was independent of body mass.

CONCLUSION

These findings highlight the intricate interplay between insulin resistance, genetic factors, and immune activation in the context of T1D susceptibility, indicating potential connections between insulin resistance and immune responses specific to islet cells.

High-Intensity Interval Training for Individuals With Isolated Impaired Fasting Glucose: Protocol for a Proof-of-Concept Randomized Controlled Trial

BACKGROUND

Standard lifestyle interventions have shown limited efficacy in preventing type 2 diabetes among individuals with isolated impaired fasting glucose (i-IFG). Hence, tailored intervention approaches are necessary for this high-risk group.

OBJECTIVE

This study aims to (1) assess the feasibility of conducting a high-intensity interval training (HIIT) study and the intervention acceptability among individuals with i-IFG, and (2) investigate the preliminary efficacy of HIIT in reducing fasting plasma glucose levels and addressing the underlying pathophysiology of i-IFG.

METHODS

This study is a 1:1 proof-of-concept randomized controlled trial involving 34 physically inactive individuals (aged 35-65 years) who are overweight or obese and have i-IFG. Individuals will undergo a 3-step screening procedure to determine their eligibility: step 1 involves obtaining clinical information from electronic health records, step 2 consists of completing questionnaires, and step 3 includes blood tests. All participants will be fitted with continuous glucose monitoring devices for approximately 80 days, including 10 days prior to the intervention, the 8-week intervention period, and 10 days following the intervention. Intervention participants will engage in supervised HIIT sessions using stationary "spin" cycle ergometers in groups of 5 or fewer. The intervention will take place 3 times a week for 8 weeks at the Aerobic Exercise Laboratory in the Rehabilitation Hospital at Emory University. Control participants will be instructed to refrain from engaging in intense physical activities during the study period. All participants will receive instructions to maintain a eucaloric diet throughout the study. Baseline and 8-week assessments will include measurements of weight, blood pressure, body composition, waist and hip circumferences, as well as levels of fasting plasma glucose, 2-hour plasma glucose, and fasting insulin. Primary outcomes include feasibility parameters, intervention acceptability, and participants' experiences, perceptions, and satisfaction with the HIIT intervention, as well as facilitators and barriers to participation. Secondary outcomes comprise between-group differences in changes in clinical measures and continuous glucose monitoring metrics from baseline to 8 weeks. Quantitative data analysis will include descriptive statistics, correlation, and regression analyses. Qualitative data will be analyzed using framework-driven and thematic analyses.

RESULTS

Recruitment for the study is scheduled to begin in February 2025, with follow-up expected to be completed by the end of September 2025. We plan to publish the study findings by the end of 2025.

CONCLUSIONS

The study findings are expected to guide the design and execution of an adequately powered randomized controlled trial for evaluating HIIT efficacy in preventing type 2 diabetes among individuals with i-IFG.

TRIAL REGISTRATION

Clinicaltrials.gov NCT06143345; https://clinicaltrials.gov/study/NCT06143345.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

PRR1-10.2196/59842.

Insulin Sensitivity and Muscle Loss in the Absence of Diabetes Mellitus: Findings from a Longitudinal Community-Based Cohort Study

Background/Objectives: Muscle loss is a serious complication in chronic disease patients, yet studies on long-term changes in muscle mass based on insulin sensitivity in the absence of diabetes mellitus are scarce. This community-based cohort study analyzed the longitudinal association between insulin sensitivity and muscle loss in middle-aged South Korean adults. Methods: This study included 6016 subjects (aged 40-65 years) from the Korean Genome and Epidemiology Study, conducted between 2001 and 2016. Fat-free mass, fat mass, body weight, and kidney function were assessed biennially. Subjects were categorized into four groups based on the composite (Matsuda) insulin sensitivity index (ISI) quartiles. The primary outcome was muscle loss, defined as a decline in fat-free mass of 10% or more from baseline. The secondary outcome was the occurrence of all-cause mortality. Results: During 69,480 person-years of follow-up, muscle loss occurred in 311 (5.2%) subjects. Multivariable Cox regression revealed a reverse-graded association between insulin sensitivity and muscle loss risk. Hazard ratios (95% confidence intervals) for the second, third, and highest ISI quartiles were 0.70 (0.51-0.94), 0.69 (0.50-0.95), and 0.65 (0.46-0.92), respectively, compared with the lowest quartile. Insulin sensitivity, however, was not significantly associated with all-cause mortality, though the mortality risk was higher in individuals with muscle loss. Conclusions: A reverse-graded relationship between insulin sensitivity and muscle loss risk was identified in middle-aged South Korean adults, with the lowest risk in the highest ISI quartile. These findings suggest that higher insulin sensitivity may reduce the risk of muscle loss.

Sex hormone-binding globulin, testosterone and type 2 diabetes risk in middle-aged African women: exploring the impact of HIV and menopause

Objectives

Sex hormone-binding globulin (SHBG) and testosterone are differentially associated with type 2 diabetes (T2D) risk. We investigated whether these associations differ by HIV and menopausal status in Black South African women living with (WLWH) and without HIV (WLWOH).

Design

Cross-sectional observational.

Methods

Eighty one premenopausal (57 WLWOH, 24 WLWH) and 280 postmenopausal (236 WLWOH, 44 WLWH) women from the Middle-Aged Soweto Cohort (MASC) completed the following measures: circulating SHBG and sex hormones, body composition (dual energy x-ray absorptiometry), oral glucose tolerance test to estimate insulin sensitivity (Matsuda index), secretion (insulinogenic index, IGI) and clearance, and beta-cell function (disposition index, DI). Dysglycaemia was defined as either impaired fasting or postprandial glucose or T2D.

Results

SHBG was higher and total and free testosterone were lower in postmenopausal WLWH than WLWOH (all p≤0.023). Irrespective of HIV serostatus, SHBG was positively associated with Matsuda index, insulin clearance and DI and inversely with HOMA-IR (all p<0.011). The association between SHBG and Matsuda index was stronger in premenopausal than postmenopausal women (p=0.043 for interaction). Free testosterone (and not total testosterone) was only negatively associated with basal insulin clearance (p=0.021), and positively associated with HOMA-IR in premenopausal and not post-menopausal women (p=0.015 for interaction).

Conclusions

We show for the first time that midlife African WLWH have higher SHBG and lower total and free testosterone than WLWOH, which corresponded to their higher beta-cell function, suggesting a putative protective effect of SHBG on T2D risk in WLWH.

Efficacy of the Once-Daily Tacrolimus Formulation LCPT Compared to the Immediate-Release Formulation in Preventing Early Post-Transplant Diabetes in High-Risk Kidney Transplant Patients: A Randomized, Controlled, Open-Label Pilot Study (EUDRACT: 2017-000718-52)

Background/Objectives: Post-transplant diabetes mellitus (PTDM) and prediabetes (PreDM) are common after renal transplantation and increase the risk of cardiovascular events and mortality. Compared to immediate-release tacrolimus (IR-Tac), the LCPT formulation, with delayed absorption, offers higher bioavailability and a smoother time-concentration curve, potentially reducing beta-cell stress. Methods: This randomized pilot trial compared de novo immunosuppression with IR-Tac (twice daily) and LCPT (once daily). At-risk recipients (age ≥ 60 years or 18-59 years with metabolic syndrome) were enrolled and followed for 3 months. The primary and secondary outcomes were the incidence of PTDM and PreDM, respectively. Results: 27 patients were randomized to IR-Tac and 25 to LCPT. The incidence of PTDM was comparable between groups [IR Tac: 18.5% (95% CI: 8.2-36.7%) vs. LCPT: 24% (95% CI: 11.5-43.4%); p = 0.7]. Although not statistically significant, the LCPT group exhibited a trend toward a reduction in PreDM incidence [IR-Tac: 40.7% (95% CI: 25-59%) vs. LCPT: 20% (95% CI: 9-39%); p = 0.1]. A sensitivity analysis showed similar results, with no significant differences in cumulative corticosteroid doses or baseline body mass index (BMI) between groups. The LCPT group showed a trend toward higher tacrolimus exposure at the end of the study [trough levels: IR-Tac group 8.3 (6.9-9.2) vs. LCPT group 9.4 (7.4-11.4) ng/mL; p = 0.05)], as well as fewer acute rejection episodes (none vs. three). Delayed graft function was more common in the IR-Tac group (37% vs. 8%; p = 0.01), and the eGFR was lower. Adverse events were comparable between groups. Conclusions: The potential biological activity of LCPT in preventing glucose metabolic alterations in at-risk patients warrants further investigation.

Exploring the effects of time-restricted eating on body weight and associated cardiometabolic outcomes in South African women living with HIV (TESSA): protocol for a randomised controlled trial

INTRODUCTION

We codesigned an intervention with a low-resourced community with the aim to investigate the effects of time-restricted eating (TRE) on changes in body weight and associated cardiometabolic outcomes in South African women living with overweight/obesity and HIV who have initiated dolutegravir (DTG)-based antiretroviral therapy (ART).

METHODS AND ANALYSIS

Women with overweight or obesity (body mass index ≥25 kg/m², no upper limit), aged 20-45 years, living with HIV and in a low-resourced community, and receiving DTG-based ART for less than 2 years will be recruited from a community healthcare centre in Khayelitsha, Cape Town (n=152). Participants will be randomised 1:1 to the TRE group (n=76) or standard of care control group (n=76) for 12 months. The TRE group will be required to restrict their eating window to ~8-10 hours/day and will receive nutritional information sessions at baseline and at 3, 6, 9 and 12 months. The primary outcome of body weight will be assessed at baseline and monthly. Cardiometabolic measures will be reported as secondary outcomes. At baseline, 6- and 12 months, an oral glucose tolerance test (to estimate insulin sensitivity and beta-cell function), questionnaires (sociodemographic, food insecurity, quality of life, social support and sleep quality) and a quantified food frequency questionnaire (total energy and macronutrient composition) will be completed. Every 3 months, appetite ratings, bioelectrical impedance (fat mass and fat-free mass), fasting venous bloods (glucose, insulin, gut hormones and systemic inflammation) and process evaluation (qualitative interviews) will be completed. Monthly monitoring will also include anthropometry and blood pressure.

ETHICS AND DISSEMINATION

The study is conducted in accordance with the Declaration of Helsinki and has been approved by the Human Research Ethics Committee of the University of Cape Town (628/2021). Verbal and written consent is required from study participants. Results of this study will be published in peer-reviewed journals and presented at conferences.

TRIAL REGISTRATION NUMBER

PACTR202302484999720.

Recent Glycemia Is a Major Determinant of β-Cell Function in Type 2 Diabetes Mellitus

BACKGRUOUND

Progressive deterioration of β-cell function is a characteristic of type 2 diabetes mellitus (T2DM). We aimed to investigate the relative contributions of clinical factors to β-cell function in T2DM.

METHODS

In a T2DM cohort of 470 adults (disease duration 0 to 41 years), β-cell function was estimated using insulinogenic index (IGI), disposition index (DI), oral disposition index (DIO), and homeostasis model assessment of β-cell function (HOMA-B) derived from a 75 g oral glucose tolerance test (OGTT). The relative contributions of age, sex, disease duration, body mass index, glycosylated hemoglobin (HbA1c) levels (at the time of the OGTT), area under the curve of HbA1c over time (HbA1c AUC), coefficient of variation in HbA1c (HbA1c CV), and antidiabetic agents use were compared by standardized regression coefficients. Longitudinal analyses of these indices were also performed.

RESULTS

IGI, DI, DIO, and HOMA-B declined over time (P<0.001 for all). Notably, HbA1c was the most significant factor affecting IGI, DI, DIO, and HOMA-B in the multivariable regression analysis. Compared with HbA1c ≥9%, DI was 1.9-, 2.5-, 3.7-, and 5.5-fold higher in HbA1c of 8%-<9%, 7%-<8%, 6%-<7%, and <6%, respectively, after adjusting for confounding factors (P<0.001). Conversely, β-cell function was not affected by the type or duration of antidiabetic agents, HbA1c AUC, or HbA1c CV. The trajectories of the IGI, DI, DIO, and HOMA-B mirrored those of HbA1c.

CONCLUSION

β-Cell function declines over time; however, it is flexible, being largely affected by recent glycemia in T2DM.

The correlation between patients with type 2 diabetes mellitus and chronic microvascular complications during the glucose peak time

INTRODUCTION

To assess the Type 2 Diabetes Mellitus (T2DM) patients in association with Chronic Microvascular Complications at Glucose Peak Time and the association among chronic microvascular complications in T2DM patients and the glucose peak period in the typical steamed bread meal test.

METHODS

Overall 1095 T2DM patients were classified as three groups: (1) Group G1: glucose peak time ≤ 1 h (n = 84), Group G2: 1 h < glucose peak time ≤ 2 h (n = 648) and Group G3: glucose peak time > 2 h (n = 363). The clinical characteristics, insulin characteristics and glucose peak time and chronic microvascular complications markers of patients in each group was analyzed and compared. Statistical analyses were performed using SPSS 23.0, employing chi-square tests, Kruskal-Wallis tests, one-way ANOVA, and binary logistic regression analysis, with significance set at P < 0.05.

RESULTS

Age, length of disease, glycated hemoglobin (HbA1c), urine albumin-creatinine ratio (UACR), and the number of patients with diabetic retinopathy (DR) increased (all P < 0.05) in those with postponed glucose peak time, while insulinogenic indexes, the AUC for C-p (AUCC-p), fasting, and 120-min C-peptide (C-p) decreased (all P < 0.05). Only age was connected to patients with diabetic kidney disease (DKD) independently in binary logistic regression analysis, although delayed glucose peak time was related to the presence of patients with DR. (all P < 0.05).

CONCLUSION

Delayed glucose peak time contributed to DR. Attention should be paid to condition of chronic microvascular complications in T2DM patients with a postponed peak glucose timing.

Amelioration of Insulin Resistance after Delivery Is Associated with Reduced Risk of Postpartum Diabetes in Women with Gestational Diabetes Mellitus

BACKGRUOUND

Identifying risk factors for postpartum type 2 diabetes in women with gestational diabetes mellitus (GDM) is crucial for effective interventions. We examined whether changes in insulin sensitivity after delivery affects the risk of type 2 diabetes in women with GDM.

METHODS

This prospective cohort study included 347 women with GDM or gestational impaired glucose tolerance, who attended the follow-up visits at 2 months postpartum and annually thereafter. Changes in insulin sensitivity were calculated using the Matsuda index at GDM diagnosis and at 2 months postpartum (ΔMatsuda index). After excluding women with pregestational diabetes or those followed up only once, we analyzed the risk of postpartum type 2 diabetes based on the ΔMatsuda index tertiles.

RESULTS

The incidence of type 2 diabetes at the two-month postpartum visit decreased with increasing ΔMatsuda index tertiles (16.4%, 9.5%, and 1.8%, P=0.001). During a 4.1-year follow-up, 26 out of 230 women who attended more than two follow-up visits (11.3%) developed type 2 diabetes. Compared to the lowest tertile, subjects in the highest ΔMatsuda index tertile showed a significantly reduced risk of type 2 diabetes (hazard ratio, 0.33; 95% confidence interval, 0.12 to 0.93; P=0.036) after adjusting for confounders.

CONCLUSION

Improvement in insulin sensitivity after delivery is associated with a reduced risk of postpartum type 2 diabetes in women with GDM. Postpartum changes in insulin sensitivity could be a useful prediction for future type 2 diabetes development in women with GDM.

The different associations of serum gamma-glutamyl transferase and alanine aminotransferase with insulin secretion, β-cell function, and insulin resistance in non-obese Japanese

The present study investigated the associations of serum gamma-glutamyl transferase (GGT), a marker of fatty liver and oxidative stress, and ALT/AST, a marker of fatty liver, with percentage trunk fat and postload glucose, insulin resistance, and β-cell function in middle-aged Japanese individuals, whose BMI averaged < 23.0 kg/m2. Pancreatic β-cell function was assessed using the disposition index calculated by a product of the insulinogenic index (IGI) and Matsuda insulin sensitivity index, a biomarker of early-phase glucose-stimulated insulin secretion and whole-body insulin sensitivity, respectively. Multivariate linear regression analyses revealed that the disposition index was associated inversely with GGT independently of percentage trunk fat, homeostasis model assessment insulin resistance (HOMA-IR), a marker of insulin resistance, and Matsuda index. When IGI was included instead of the disposition index, IGI (inversely) and HOMA-IR were associated with GGT independently of percentage trunk fat and Matsuda index. When the area under the glucose concentration curve (AUCg) during an oral glucose tolerance test was included instead of the disposition index, AUCg and HOMA-IR emerged as independent determinants of GGT. ALT/AST was associated with HOMA-IR alone. Results suggest a different pathophysiologic basis between GGT and ALT/AST in predicting diabetic risk in non-obese Japanese.

Enhanced interactions among gut mycobiomes with the deterioration of glycemic control

BACKGROUND

The gut mycobiome is closely linked to health and disease; however, its role in the progression of type 2 diabetes mellitus (T2DM) remains obscure. Here, a multi-omics approach was employed to explore the role of intestinal fungi in the deterioration of glycemic control.

METHODS

350 participants without hypoglycemic therapies were invited for a standard oral glucose tolerance test to determine their status of glycemic control. The gut mycobiome was identified through internal transcribed spacer sequencing, host genetics were determined by genotyping array, and plasma metabolites were measured with untargeted liquid chromatography mass spectrometry.

FINDINGS

The richness of fungi was higher, whereas its dissimilarity was markedly lower, in participants with T2DM. Moreover, the diversity and composition of fungi were closely associated with insulin sensitivity and pancreatic β-cell functions. With the exacerbation of glycemic control, the co-occurrence network among fungus taxa became increasingly complex, and the complexity of the interaction network was inversely associated with insulin sensitivity. Mendelian randomization analysis further demonstrated that the Archaeorhizomycetes class, Fusarium genus, and Neoascochyta genus were causally linked to impaired glucose metabolism. Furthermore, integrative analysis with metabolomics showed that increased 4-hydroxy-2-oxoglutaric acid, ketoleucine, lysophosphatidylcholine (20:3/0:0), and N-lactoyl-phenylalanine, but decreased lysophosphatidylcholine (O-18:2), functioned as key molecules linking the adverse effect of Fusarium genus on insulin sensitivity.

CONCLUSIONS

Our study uncovers a strong association between disturbance in gut fungi and the progression of T2DM and highlights the potential of targeting the gut mycobiome for the management of T2DM.

FUNDINGS

This study was supported by MOST and NSFC of China.

Higher Genetic Risk for Type 2 Diabetes Is Associated With a Faster Decline of β-Cell Function in an East Asian Population

OBJECTIVE

While most genetic variants of type 2 diabetes (T2D) are suggested to be associated with β-cell dysfunction cross sectionally, their association with the longitudinal change of β-cell function remains largely unknown.

RESEARCH DESIGN AND METHODS

We analyzed data from 6,311 participants without T2D at baseline (mean [SD] age 51.6 [8.7] years) from a community-based prospective cohort in Korea. Participants underwent biennial 2-h 75-g oral glucose tolerance tests (OGTTs) during 14 years of follow-up, and the OGTT-derived disposition index (DI) was used as a marker for β-cell function. Genetic risk was quantified using the genome-wide polygenic risk score (PRS) and was stratified into low (1st quintile), intermediate (2nd-4th quintiles), and high (5th quintile) genetic risk. Lifestyle was assessed according to Life's Essential 8.

RESULTS

During a mean follow-up of 10.9 years, 374 (29.6%), 851 (22.5%), and 188 (14.9%) participants developed T2D in the high, intermediate, and low genetic risk groups, respectively. Compared with the low genetic risk group, participants in the high genetic risk group had a 25% lower DI at baseline. Furthermore, in longitudinal analysis, we observed a 1.83-fold faster decline in log2-transformed DI per year (-0.034 vs. -0.019, P = 2.1 × 10-3; per 1-SD increase in T2D PRS, P = 1.2 × 10-4). Healthy lifestyle attenuated the rate of decline in DI across all genetic risk groups.

CONCLUSIONS

Individuals with a higher genetic risk for T2D exhibited not only a lower OGTT-derived β-cell function at baseline but also a notably more rapid decline during follow-up. This information could be used to enable a focused precision prevention with lifestyle intervention.

Post-Bariatric Hypoglycemia in Individuals with Obesity and Type 2 Diabetes after Laparoscopic Roux-en-Y Gastric Bypass: A Prospective Cohort Study

Post-bariatric hypoglycemia (PBH) is an increasingly recognized complication after metabolic bariatric surgery (MBS). The aim of this study is to investigate potential factors associated with PBH. A cohort of 24 patients with type 2 diabetes mellitus (T2DM) and body mass index (BMI) ≥40 kg/m2 who underwent laparoscopic Roux-en-Y gastric bypass (LRYGBP) was retrospectively investigated for PBH at 12 months. PBH was defined as postprandial glucose at 120 min below 60 mg/dL. Questionnaires based on the Edinburgh hypoglycemia scale were filled out by the participants. Glycemic parameters and gastrointestinal (GI) hormones were also investigated. Based on the questionnaires, five patients presented more than four symptoms that were highly indicative of PBH at 12 months. According to glucose values at 120 min, one patient experienced PBH at 6 months and four patients experienced it at 12 months. Postprandial insulin values at 30 min and 6 months seem to be a strong predictor for PBH (p < 0.001). GLP-1 and glucagon values were not significantly associated with PBH. PBH can affect patients with T2DM after MBS, reaching the edge of hypoglycemia. Postprandial insulin levels at 30 min and 6 months might predict the occurrence of PBH at 12 months, but this requires further validation with a larger sample size.

SHBG, Free Testosterone, and Type 2 Diabetes Risk in Middle-aged African Men: A Longitudinal Study

Objectives

To investigate longitudinal changes in SHBG and free testosterone (free T) levels among Black middle-aged African men, with and without coexistent HIV, and explore associations with incident dysglycaemia and measures of glucose metabolism.

Design

This longitudinal study enrolled 407 Black South African middle-aged men, comprising primarily 322 men living without HIV (MLWOH) and 85 men living with HIV (MLWH), with normal fasting glucose at enrollment. Follow-up assessments were conducted after 3.1 ± 1.5 years.

Methods

At baseline and follow-up, SHBG, albumin, and total testosterone were measured and free T was calculated. An oral glucose tolerance test at follow-up determined dysglycaemia (impaired fasting glucose, impaired glucose tolerance, type 2 diabetes) and glucose metabolism parameters including insulin sensitivity (Matsuda index), insulin resistance (homeostasis model assessment of insulin resistance), and beta(β)-cell function (disposition index). The primary analysis focussed on MLWOH, with a subanalysis on MLWH to explore whether associations in MLWOH differed from MLWH.

Results

The prevalence of dysglycaemia at follow-up was 17% (n = 55) in MLWOH. Higher baseline SHBG was associated with a lower risk of incident dysglycaemia (odds ratio 0.966; 95% confidence interval 0.945-0.987) and positively associated with insulin sensitivity (β = 0.124, P < .001) and β-cell function (β = 0.194, P = .001) at follow-up. Free T did not predict dysglycaemia. In MLWH, dysglycaemia prevalence at follow-up was 12% (n = 10). Neither baseline SHBG nor free T were associated with incident dysglycaemia and glucose metabolism parameters in MLWH.

Conclusion

SHBG levels predict the development of dysglycaemia in middle-aged African men but do not exhibit the same predictive value in MLWH.

Pancreatic beta-cell mass and function and therapeutic implications of using antidiabetic medications in type 2 diabetes

Nowadays, the focus of diabetes treatment has switched from lowering the glucose level to preserving glycemic homeostasis and slowing the disease progression. The main pathophysiology of both type 1 diabetes and long-standing type 2 diabetes is pancreatic β-cell mass loss and dysfunction. According to recent research, human pancreatic β-cells possess the ability to proliferate in response to elevated insulin demands. It has been demonstrated that in insulin-resistant conditions in humans, such as obesity or pregnancy, the β-cell mass increases. This ability could be helpful in developing novel treatment approaches to restore a functional β-cell mass. Treatment strategies aimed at boosting β-cell function and mass may be a useful tool for managing diabetes mellitus and stopping its progression. This review outlines the processes of β-cell failure and detail the many β-cell abnormalities that manifest in people with diabetes mellitus. We also go over standard techniques for determining the mass and function of β-cells. Lastly, we provide the therapeutic implications of utilizing antidiabetic drugs in controlling the mass and function of pancreatic β-cells.

Metabolic-associated fatty liver disease is characterized by a post-oral glucose load hyperinsulinemia in individuals with mild metabolic alterations

Metabolic-associated fatty liver disease (MAFLD) has been identified as risk factor of incident type 2 diabetes (T2D), but the underlying postprandial mechanisms remain unclear. We compared the glucose metabolism, insulin resistance, insulin secretion, and insulin clearance post-oral glucose tolerance test (OGTT) between individuals with and without MAFLD. We included 50 individuals with a body mass index (BMI) between 25 and 40 kg/m2 and ≥1 metabolic alteration: increased fasting triglycerides or insulin, plasma glucose 5.5-6.9 mmol/L, or glycated hemoglobin 5.7-5.9%. Participants were grouped according to MAFLD status, defined as hepatic fat fraction (HFF) ≥5% on MRI. We used oral minimal model on a frequently sampled 3 h 75 g-OGTT to estimate insulin sensitivity, insulin secretion, and pancreatic β-cell function. Fifty percent of participants had MAFLD. Median age (IQR) [57 (45-65) vs. 57 (44-63) yr] and sex (60% vs. 56% female) were comparable between groups. Post-OGTT glucose concentrations did not differ between groups, whereas post-OGTT insulin concentrations were higher in the MAFLD group (P < 0.03). Individuals with MAFLD exhibited lower insulin clearance, insulin sensitivity, and first-phase pancreatic β-cell function. In all individuals, increased insulin incremental area under the curve and decreased insulin clearance were associated with HFF after adjusting for age, sex, and BMI (P < 0.02). Among individuals with metabolic alterations, the presence of MAFLD was characterized mainly by post-OGTT hyperinsulinemia and reduced insulin clearance while exhibiting lower first phase β-cell function and insulin sensitivity. This suggests that MAFLD is linked with impaired insulin metabolism that may precede T2D.NEW & NOTEWORTHY Using an oral glucose tolerance test, we found hyperinsulinemia, lower insulin sensitivity, lower insulin clearance, and lower first-phase pancreatic β-cell function in individuals with MAFLD. This may explain part of the increased risk of incident type 2 diabetes in this population. These data also highlight implications of hyperinsulinemia and impaired insulin clearance in the progression of MAFLD to type 2 diabetes.

Glucagon kinetics assessed by mathematical modelling during oral glucose administration in people spanning from normal glucose tolerance to type 2 diabetes

Background/Objectives

Glucagon is important in the maintenance of glucose homeostasis, with also effects on lipids. In this study, we aimed to apply a recently developed model of glucagon kinetics to determine the sensitivity of glucagon variations (especially, glucagon inhibition) to insulin levels ("alpha-cell insulin sensitivity"), during oral glucose administration.

Subjects/Methods

We studied 50 participants (spanning from normal glucose tolerance to type 2 diabetes) undergoing frequently sampled 5-hr oral glucose tolerance test (OGTT). The alpha-cell insulin sensitivity and the glucagon kinetics were assessed by a mathematical model that we developed previously.

Results

The alpha-cell insulin sensitivity parameter (named SGLUCA; "GLUCA": "glucagon") was remarkably variable among participants (CV=221%). SGLUCA was found inversely correlated with the mean glycemic values, as well as with 2-hr glycemia of the OGTT. When stratifying participants into two groups (normal glucose tolerance, NGT, N=28, and impaired glucose regulation/type 2 diabetes, IGR_T2D, N=22), we found that SGLUCA was lower in the latter (1.50 ± 0.50·10-2 vs. 0.26 ± 0.14·10-2 ng·L-1 GLUCA/pmol·L-1 INS, in NGT and IGR_T2D, respectively, p=0.009; "INS": "insulin").

Conclusions

The alpha-cell insulin sensitivity is highly variable among subjects, and it is different in groups at different glucose tolerance. This may be relevant for defining personalized treatment schemes, in terms of dietary prescriptions but also for treatments with glucagon-related agents.

Triglyceride-glucose index predicts type 2 diabetes mellitus more effectively than oral glucose tolerance test-derived insulin sensitivity and secretion markers

AIMS

We explored the role of the triglyceride-glucose (TyG) index as an early and superior predictor of type 2 diabetes mellitus (T2DM) in individuals with normal glucose tolerance (NGT) using a community-based Korean cohort over 18 years.

METHODS

We retrospectively examined 6,072 adults with NGT from the Korean Genome and Epidemiology Study. Cox proportional hazard regression models were employed to evaluate the risk of incidence of T2DM and receiver operating characteristic analysis was used to calculate the area under the curve (AUC).

RESULTS

At baseline, the TyG index correlated with the homeostasis model assessment of insulin resistance (HOMA-IR) and the composite insulin sensitivity index (ISI) (β: 0.045, p < 0.001; β: -0.105, p < 0.001, respectively). Over the 18-year follow-up period, 999 individuals developed T2DM. An increase in the TyG quartile independently predicted the incidence of T2DM [hazard ratio, 2.36 (1.9-2.93) for Q4]. The AUC value of the TyG index was 0.642, the highest value among HOMA-IR and OGTT-derived insulin sensitivity and secretion markers.

CONCLUSIONS

The TyG index is associated with HOMA-IR and composite ISI even with NGT. The TyG index demonstrated independent predictability for T2DM incidence in individuals with NGT, better than OGTT-derived insulin sensitivity and secretion markers.

Unveiling the connection between gut microbiome and metabolic health in individuals with chronic spinal cord injury

Accumulating evidence has revealed that alterations in the gut microbiome following spinal cord injury (SCI) exhibit similarities to those observed in metabolic syndrome. Considering the causal role of gut dysbiosis in metabolic syndrome development, SCI-induced gut dysbiosis may be a previously unidentified contributor to the increased risk of cardiometabolic diseases, which has garnered attention. With a cross-sectional design, we evaluated the correlation between gut microbiome composition and functional potential with indicators of metabolic health among 46 individuals with chronic SCI. Gut microbiome communities were profiled using next-generation sequencing techniques. Indices of metabolic health, including fasting lipid profile, glucose tolerance, insulin resistance, and inflammatory markers, were assessed through fasting blood tests and an oral glucose tolerance test. We used multivariate statistical techniques (i.e., regularized canonical correlation analysis) to identify correlations between gut bacterial communities, functional pathways, and metabolic health indicators. Our findings spotlight bacterial species and functional pathways associated with complex carbohydrate degradation and maintenance of gut barrier integrity as potential contributors to improved metabolic health. Conversely, those correlated with detrimental microbial metabolites and gut inflammatory pathways demonstrated associations with poorer metabolic health outcomes. This cross-sectional investigation represents a pivotal initial step toward comprehending the intricate interplay between the gut microbiome and metabolic health in SCI. Furthermore, our results identified potential targets for future research endeavors to elucidate the role of the gut microbiome in metabolic syndrome in this population.NEW & NOTEWORTHY Spinal cord injury (SCI) is accompanied by gut dysbiosis and the impact of this on the development of metabolic syndrome in this population remains to be investigated. Our study used next-generation sequencing and multivariate statistical analyses to explore the correlations between gut microbiome composition, function, and metabolic health indices in individuals with chronic SCI. Our results point to potential gut microbial species and functional pathways that may be implicated in the development of metabolic syndrome.

Association between area under the C-peptide curve during an oral glucose tolerance test and diabetic retinopathy in type 2 diabetes patients

AIMS/INTRODUCTION

To evaluate the relative contributions of the area under the C-peptide curve (AUCC ) in diabetic retinopathy (DR) during an oral glucose tolerance test and C-peptide release test in patients with type 2 diabetes.

MATERIALS AND METHODS

We retrospectively analyzed the data of 969 patients. Their general characteristics were retrieved. A series of parameters for assessing pancreatic β-cells function, such as the AUCC for six time periods: 0-60 min (AUCC0-60 ), 0-120 min (AUCC0-120 ), 0-180 min (AUCC0-180 ), 60-120 min (AUCC60-120 ), 60-180 min (AUCC60-180 ) and 120-180 min (AUCC120-180 ); the area under the glucose-time curve for six time periods: 0-60 min (AUCG0-60 ), 0-120 min (AUCG0-120 ), 0-180 min (AUCG0-180 ), 60-120 min (AUCG60-120 ), 60-180 min (AUCG60-180 ) and 120-180 min (AUCG120-180 ) and their related indexes, were calculated through 0-180 min oral glucose tolerance test and C-peptide release test. We used univariate analysis to examine the potential factors affecting DR. Spearman's correlation was used to analyze the correlation between AUCC -related indexes and DR. The logistic regression model was used to investigate AUCC and its related indexes' contribution to incidence DR. A smooth curve fitting model was used to determine the correlation, non-linear relationship, and threshold effect between AUCC and DR.

RESULTS

Of the 969 patients with type 2 diabetes, 469 (48.40%) and 500 (51.60%) were classified as the DR group and non-DR group. Compared with the non-DR group, the DR patients had lower AUCC and AUCC /AUCG . Spearman's correlation analysis showed that AUCC -related indexes were all negatively correlated with DR. The logistic regression analysis determined that there were associations between AUCC and DR in the adjusted models. The odds ratio values of AUCC0-60 , AUCC0-120 , AUCC0-180 , AUCC0-60 /AUCG0-60 , AUCC0-120 /AUCG0-120 , AUCC0-180 /AUCG0-180 , AUCC60-120 , AUCC60-180 , AUCC120-180 , AUCC60-120 /AUCG60-120 , AUCC60-180 /AUCG60-180 and AUCC120-180 /AUCG120-180 were 0.817 (0.750, 0.890), 0.925 (0.895, 0.955), 0.951 (0.932, 0.970), 0.143 (0.060, 0.340), 0.194 (0.093, 0.406), 0.223 (0.116, 0.427), 0.886 (0.842, 0.933), 0.939 (0.915, 0.963), 0.887 (0.846, 0.930), 0.253 (0.133, 0.479), 0.282 (0.160, 0.497) and 0.355 (0.220, 0.573), respectively. AUCC showed a non-linear relationship with DR, with an inflection point. The inflection points of AUCC180 /AUCG180 , AUCC60-120 , AUCC60-180 , AUCC120-180 , AUCC60-120 /AUCG60-120 , AUCC60-180 /AUCG60-180 , AUCC120-180 /AUCG120-180 and DR were 17.51, 0.542, 6.6, 15.7, 8.23, 0.534, 0.593 and 0.808 (P < 0.0001). When the indexes related to the AUCC were less than the inflection point value, they were significantly negatively associated with DR.

CONCLUSIONS

The indexes related to the AUCC for six time periods during an oral glucose tolerance test and C-peptide release test was closely associated with the incidence to DR in patients with type 2 diabetes. AUCC has the added advantage of being a cheap and convenient risk assessment over traditional ophthalmic screening.

HOMA-IR and the Matsuda Index as predictors of progression to type 1 diabetes in autoantibody-positive relatives

AIM/HYPOTHESIS

We assessed whether HOMA-IR and the Matsuda Index are associated with transitions through stages of type 1 diabetes.

METHODS

Autoantibody (AAb)-positive relatives of individuals with type 1 diabetes (n=6256) from the TrialNet Pathway to Prevention were studied. Associations of indicators of insulin resistance (HOMA-IR) and insulin sensitivity (Matsuda Index) with BMI percentile (BMIp) and age were assessed with adjustments for measures of insulin secretion, Index60 and insulinogenic index (IGI). Cox regression was used to determine if tertiles of HOMA-IR and Matsuda Index predicted transitions from Not Staged (<2 AAbs) to Stage 1 (≥2 AAbs and normoglycaemia), from Stage 1 to Stage 2 (≥2 AAbs with dysglycaemia), and progression to Stage 3 (diabetes as defined by WHO/ADA criteria).

RESULTS

There were strong associations of HOMA-IR (positive) and Matsuda Index (inverse) with baseline age and BMIp (p<0.0001). After adjustments for Index60, transitioning from Stage 1 to Stage 2 was associated with higher HOMA-IR and lower Matsuda Index (HOMA-IR: HR=1.71, p<0.0001; Matsuda Index, HR=0.40, p<0.0001), as with progressing from Stages 1 or 2 to Stage 3 (HOMA-IR: HR=1.98, p<0.0001; Matsuda Index: HR=0.46, p<0.0001). Without adjustments, associations of progression to Stage 3 were inverse for HOMA-IR and positive for Matsuda Index, opposite in directionality with adjustments. When IGI was used in place of Index60, the findings were similar.

CONCLUSIONS/INTERPRETATION

Progression to Stages 2 and 3 of type 1 diabetes increases with HOMA-IR and decreases with the Matsuda Index after adjustments for insulin secretion. Indicators of insulin secretion appear helpful for interpreting associations of progression to type 1 diabetes with HOMA-IR or the Matsuda Index in AAb-positive relatives.

Insulin Sensitivity, Islet Cell Function, and Incretin Axis in Pregnant Women With and Without Gestational Diabetes Mellitus

INTRODUCTION

The aim of this study was to compare insulin sensitivity, islet cell function, and incretin axes in pregnant subjects with GDM and normal healthy controls.

METHODS

Pregnant women at 24 to 28 weeks of gestation were subjected to a 75 g oral glucose tolerance test (OGTT). Samples for glucose, insulin, glucagon, glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) were collected at 0, 30, 60, and 120 min during the OGTT. The Matsuda index (MI) and insulin secretion and sensitivity index-2 (ISSI-2) were assessed. The glucagon suppression index (GSI) was calculated along with the area under the curve (AUC) for glucose, insulin, glucagon, GLP-1, and GIP.

RESULTS

A total of 48 pregnant women (25 GDM and 23 controls) were finally analysed. The MI and ISSI-2 were low in the GDM group [4.31 vs. 5.42; P = 0.04], [1.99 vs. 3.18, P ≤ 0.01] respectively). Total AUCglucagon was higher in the GDM group (7411.7 vs. 6320.1, P = 0.02). GSI30 was significantly lower in the GDM group (-62.6 vs. -24.7, P = 0.03). Fasting GLP-1 levels were low in GDM women (17.3 vs. 22.2, P = 0.04). The total AUCGLP-1 positively correlated with total GSI in the GDM group.

CONCLUSION

Asian-Indian GDM women have high insulin insensitivity, islet cell dysfunction, and low fasting GLP-1. Incretin axis dysfunction plays a potential role in their islet cell dysfunction.

Mechanisms of weight loss-induced remission in people with prediabetes: a post-hoc analysis of the randomised, controlled, multicentre Prediabetes Lifestyle Intervention Study (PLIS)

BACKGROUND

Remission of type 2 diabetes can occur as a result of weight loss and is characterised by liver fat and pancreas fat reduction and recovered insulin secretion. In this analysis, we aimed to investigate the mechanisms of weight loss- induced remission in people with prediabetes.

METHODS

In this prespecified post-hoc analysis, weight loss-induced resolution of prediabetes in the randomised, controlled, multicentre Prediabetes Lifestyle Intervention Study (PLIS) was assessed, and the results were validated against participants from the Diabetes Prevention Program (DPP) study. For PLIS, between March 1, 2012, and Aug 31, 2016, participants were recruited from eight clinical study centres (including seven university hospitals) in Germany and randomly assigned to receive either a control intervention, a standard lifestyle intervention (ie, DPP-based intervention), or an intensified lifestyle intervention for 12 months. For DPP, participants were recruited from 23 clinical study centres in the USA between July 31, 1996, and May 18, 1999, and randomly assigned to receive either a standard lifestyle intervention, metformin, or placebo. In both PLIS and DPP, only participants who were randomly assigned to receive lifestyle intervention or placebo and who lost at least 5% of their bodyweight were included in this analysis. Responders were defined as people who returned to normal fasting plasma glucose (FPG; <5·6 mmol/L), normal glucose tolerance (<7·8 mmol/L), and HbA1c less than 39 mmol/mol after 12 months of lifestyle intervention or placebo or control intervention. Non-responders were defined as people who had FPG, 2 h glucose, or HbA1c more than these thresholds. The main outcomes for this analysis were insulin sensitivity, insulin secretion, visceral adipose tissue (VAT), and intrahepatic lipid content (IHL) and were evaluated via linear mixed models.

FINDINGS

Of 1160 participants recruited to PLIS, 298 (25·7%) had weight loss of 5% or more of their bodyweight at baseline. 128 (43%) of 298 participants were responders and 170 (57%) were non-responders. Responders were younger than non-responders (mean age 55·6 years [SD 9·9] vs 60·4 years [8·6]; p<0·0001). The DPP validation cohort included 683 participants who lost at least 5% of their bodyweight at baseline. Of these, 132 (19%) were responders and 551 (81%) were non-responders. In PLIS, BMI reduction was similar between responders and non-responders (responders mean at baseline 32·4 kg/m2 [SD 5·6] to mean at 12 months 29·0 kg/m2 [4·9] vs non-responders 32·1 kg/m2 [5·9] to 29·2 kg/m2 [5·4]; p=0·86). However, whole-body insulin sensitivity increased more in responders than in non-responders (mean at baseline 291 mL/[min × m2], SD 60 to mean at 12 months 378 mL/[min × m2], 56 vs 278 mL/[min × m2], 62, to 323 mL/[min × m2], 66; p<0·0001), whereas insulin secretion did not differ within groups over time or between groups (responders mean at baseline 175 pmol/mmol [SD 64] to mean at 12 months 163·7 pmol/mmol [60·6] vs non-responders 158·0 pmol/mmol [55·6] to 154·1 pmol/mmol [56·2]; p=0·46). IHL decreased in both groups, without a difference between groups (responders mean at baseline 10·1% [SD 8·7] to mean at 12 months 3·5% [3·9] vs non-responders 10·3% [8·1] to 4·2% [4·2]; p=0·34); however, VAT decreased more in responders than in non-responders (mean at baseline 6·2 L [SD 2·9] to mean at 12 months 4·1 L [2·3] vs 5·7 L [2·3] to 4·5 L [2·2]; p=0·0003). Responders had a 73% lower risk of developing type 2 diabetes than non-responders in the 2 years after the intervention ended.

INTERPRETATION

By contrast to remission of type 2 diabetes, resolution of prediabetes was characterised by an improvement in insulin sensitivity and reduced VAT. Because return to normal glucose regulation (NGR) prevents development of type 2 diabetes, we propose the concept of remission of prediabetes in analogy to type 2 diabetes. We suggest that remission of prediabetes should be the primary therapeutic aim in individuals with prediabetes.

FUNDING

German Federal Ministry for Education and Research via the German Center for Diabetes Research; the Ministry of Science, Research and the Arts Baden-Württemberg; the Helmholtz Association and Helmholtz Munich; the Cluster of Excellence Controlling Microbes to Fight Infections; and the German Research Foundation.

Safety and effectiveness of metformin plus lifestyle intervention compared with lifestyle intervention alone in preventing progression to diabetes in a Chinese population with impaired glucose regulation: a multicentre, open-label, randomised controlled trial

BACKGROUND

Impaired glucose regulation (defined as either impaired glucose tolerance or impaired fasting glucose) is an important risk factor for the development of diabetes. We aimed to evaluate the safety and effectiveness of metformin plus lifestyle intervention compared with lifestyle intervention alone in preventing diabetes in Chinese participants with impaired glucose regulation.

METHODS

We did a multicentre, open-label, randomised controlled trial at 43 endocrinology departments in general hospitals across China. Eligible participants were individuals with impaired glucose regulation (ie, impaired glucose tolerance or impaired fasting glucose, or both), men or women aged 18-70 years with a BMI of 21-32 kg/m2. Eligible participants were randomly assigned (1:1) via a computer-generated randomisation to receive either standard lifestyle intervention alone or metformin (850 mg orally once per day for the first 2 weeks and titrated to 1700 mg orally per day [850 mg twice per day]) plus lifestyle intervention. Block randomisation was used with a block size of four, stratified by glucose status (impaired fasting glucose or impaired glucose tolerance), hypertension, and use of any anti-hypertensive medication. Lifestyle intervention advice was given by investigators at all participating sites. The primary endpoint was the incidence of newly diagnosed diabetes at the end of the 2-year follow-up. Analysis was done using the full analysis set and per-protocol set. This study is registered with ClinicalTrials.gov, number NCT03441750, and is completed.

FINDINGS

Between April, 2017, and June, 2019, 3881 individuals were assessed for eligibility, of which 1678 (43·2%) participants were randomly assigned to either the metformin plus lifestyle intervention group (n=831) or the lifestyle intervention alone group (n=847) and received the allocated intervention at least once. During a median follow-up of 2·03 years, the incidence rate of diabetes was 17·27 (95% CI 15·19-19·56) per 100 person-years in the metformin plus lifestyle intervention group and 19·83 (17·67-22·18) per 100 person-years in the lifestyle intervention alone group. The metformin plus lifestyle intervention group showed a 17% lower risk of developing diabetes than the lifestyle intervention alone group (HR 0·83 [95% CI 0·70-0·99]; log-rank p=0·043). A higher proportion of participants in the metformin plus lifestyle intervention group reported adverse events than in the lifestyle intervention alone group, primarily due to more gastrointestinal adverse events. The percentage of participants reporting a serious adverse event was similar in both groups.

INTERPRETATION

Metformin plus lifestyle intervention further reduced the risk of developing diabetes than lifestyle intervention alone in Chinese people with impaired glucose regulation, showing additional benefits of combined intervention in preventing progression to diabetes without new safety concerns.

FUNDING

Merck Serono China, an affiliate of Merck KGaA, Darmstadt, Germany.

TRANSLATION

For the Chinese translation of the abstract see Supplementary Materials section.

Changes in glucose metabolism among recipients with diabetes 1 year after kidney transplant: a multicenter 1-year prospective study

Background

Diabetes mellitus is a common and crucial metabolic complication in kidney transplantation. It is necessary to analyze the course of glucose metabolism in patients who already have diabetes after receiving a transplant. In this study, we investigated the changes in glucose metabolism after transplantation, and a detailed analysis was performed on some patients whose glycemic status improved.

Methods

The multicenter prospective cohort study was conducted between 1 April 2016 and 31 September 2018. Adult patients (aged 20 to 65 years) who received kidney allografts from living or deceased donors were included. Seventy-four subjects with pre-transplant diabetes were followed up for 1 year after kidney transplantation. Diabetes remission was defined as the results of the oral glucose tolerance test performed one year after transplantation and the presence or absence of diabetes medications. After 1-year post-transplant, 74 recipients were divided into the persistent diabetes group (n = 58) and the remission group (n = 16). Multivariable logistic regression was performed to identify clinical factors associated with diabetes remission.

Results

Of 74 recipients, 16 (21.6%) showed diabetes remission after 1-year post-transplant. The homeostatic model assessment for insulin resistance numerically increased in both groups throughout the first year after transplantation and significantly increased in the persistent diabetes group. The insulinogenic index (IGI₃₀) value significantly increased only in the remission group, and the IGI₃₀ value remained low in the persistent diabetes group. In univariate analysis, younger age, newly diagnosed diabetes before transplantation, low baseline hemoglobin A1c, and high baseline IGI₃₀ were significantly associated with remission of diabetes. After multivariate analysis, only newly diagnosed diabetes before transplantation and IGI₃₀ at baseline were associated with remission of diabetes (34.00 [1.192-969.84], P = 0.039, and 17.625 [1.412-220.001], P = 0.026, respectively).

Conclusion

In conclusion, some kidney recipients with pre-transplant diabetes have diabetes remission 1 year after transplantation. Our prospective study revealed that preserved insulin secretory function and newly diagnosed diabetes at the time of kidney transplantation were favorable factors for which glucose metabolism did not worsen or improve 1 year after kidney transplantation.

Inflammation on the Waiting List Is a Risk Factor for New-Onset Prediabetes and Post-Transplant Diabetes Mellitus: A Prospective Study

INTRODUCTION

Inflammation is a risk factor for diabetes in the general population. The role of inflammation in prediabetes or post-transplant diabetes mellitus (PTDM) is not clear. We evaluated the association between inflammatory markers in patients on the waiting list for renal transplantation and the onset of prediabetes and PTDM 12 months after transplantation.

METHODS

This is a post hoc analysis of a prospective study that included nondiabetic patients on the waiting list for kidney transplantation who underwent an oral glucose tolerance test (OGTT) and were followed up to 12 months after transplantation. At this time, those patients without PTDM underwent another OGTT. At pre-transplantation, five cytokines: TNFα, IL6, IL1β, CRP, MCP1 were determined. The association between inflammation and prediabetes/PTDM was evaluated using multiple regression models.

RESULTS

110 patients on the waiting list were enrolled: 74 had normal glucose metabolism and 36 had prediabetes or occult diabetes. At 12 months, 53 patients had normal glucose metabolism, 25 prediabetes, and 32 PTDM. In multiple regression analysis, pre-transplant inflammation was not a risk factor for prediabetes or PTDM. This was attributed to the high interrelation between obesity, prediabetes, and inflammation: about 75% of the cases had these conditions. In a sub-analysis, we analyzed only patients without prediabetes and occult diabetes on the waiting list and found that TNFα levels and BMI at pre-transplantation were independently associated with the onset of prediabetes or PTDM 1 year after transplantation.

CONCLUSIONS

Pre-transplant inflammation and BMI are risk factors for prediabetes and PTDM in patients without glucose metabolism alterations.

Serum fibroblast growth factor 1 and its association with pancreatic beta cell function and insulin sensitivity in adults with glucose intolerance

Background

Beneficial role of fibroblast growth factor 1 (FGF1) in the regulation of glucose metabolism and adipose tissue remodeling was suggested in rodents. This study aimed to investigate the association between serum FGF1 levels and metabolic parameters in adults with glucose intolerance.

Methods

Serum FGF1 levels were examined using an enzyme-linked immunosorbent assay in 153 individuals with glucose intolerance. Associations between serum FGF1 levels and metabolic parameters, including body mass index (BMI), glycated hemoglobin (HbA1c), and 75 g oral glucose tolerance test-derived parameters, including insulinogenic index (IGI), Matsuda insulin sensitivity index (ISI), and disposition index (DI), were examined.

Results

Serum FGF1 was detected in 35 individuals (22.9%), possibly due to the autocrine/paracrine nature of the peptide. IGI and DI levels were significantly lower in individuals with higher FGF1 levels than in those with lower FGF1 levels or undetectable FGF1 (p=0.006 and 0.005 for IGI and DI, respectively, after adjustment for age, sex, and BMI). Univariable and multivariable analyses using the Tobit regression model also revealed a negative association between FGF1 levels and IGI and DI. The regression coefficients per 1-SD of log-transformed IGI and DI were -0.461 (p=0.013) and -0.467 (p=0.012), respectively, after adjustment for age, sex, and BMI. In contrast, serum FGF1 levels were not significantly associated with ISI, BMI, or HbA1c.

Conclusions

The serum concentration of FGF1 was significantly elevated in individuals with low insulin secretion, suggesting a possible interaction between FGF1 and beta cell function in humans.

The Glycemic Curve during the Oral Glucose Tolerance Test: Is It Only Indicative of Glycoregulation?

The shape of the glycemic curve during the oral glucose tolerance test (OGTT), interpreted in the correct context, can predict impaired glucose homeostasis. Our aim was to reveal information inherent in the 3 h glycemic trajectory that is of physiological relevance concerning the disruption of glycoregulation and complications beyond, such as components of metabolic syndrome (MS).

METHODS

In 1262 subjects (1035 women, 227 men) with a wide range of glucose tolerance, glycemic curves were categorized into four groups: monophasic, biphasic, triphasic, and multiphasic. The groups were then monitored in terms of anthropometry, biochemistry, and timing of the glycemic peak.

RESULTS

Most curves were monophasic (50%), then triphasic (28%), biphasic (17.5%), and multiphasic (4.5%). Men had more biphasic curves than women (33 vs. 14%, respectively), while women had more triphasic curves than men (30 vs. 19%, respectively) (p < 0.01). Monophasic curves were more frequent in people with impaired glucose regulation and MS compared to bi-, tri-, and multiphasic ones. Peak delay was the most common in monophasic curves, in which it was also most strongly associated with the deterioration of glucose tolerance and other components of MS.

CONCLUSION

The shape of the glycemic curve is gender dependent. A monophasic curve is associated with an unfavorable metabolic profile, especially when combined with a delayed peak.

Association of long-term hyperglycaemia and insulin resistance with brain atrophy and cognitive decline: A longitudinal cohort study

AIM

To investigate the longitudinal changes in brain volume and cognitive function associated with diabetes at midlife, and to examine whether long-term hyperglycaemia, insulin resistance or secretory function is associated with brain atrophy and cognitive decline.

MATERIALS AND METHODS

We used data from 2377 participants with both baseline and 4-year follow-up brain magnetic resonance images and neuropsychological measures from the Ansan cohort of the Korean Genome Epidemiology Study. Time-weighted mean glycaemic values were calculated using all measurements over an average duration of 10.6 years from cohort initiation to baseline visits.

RESULTS

Type 2 diabetes was associated with greater white matter volume reduction (adjusted volume difference = -1.96 ml, 95% CI: -3.73, -0.18) and executive function decline (adjusted Z score difference = -0.14, 95% CI: -0.23, -0.05) during the follow-up period of 4.2 years. Decline of verbal and visual memory or verbal fluency was not associated with diabetes. Greater executive function decline was associated with higher time-weighted mean HbA1c level over the preceding 10.6 years (P < .001), but not with insulin resistance markers in the diabetes group. Participants with diabetes, whose time-weighted average HbA1c level was maintained above 6.5% over the previous decade, showed greater decline in executive function and global cognition than the normal glucose group.

CONCLUSIONS

Long-term hyperglycaemia was a major independent factor associated with rapid cognitive decline in middle-aged adults with diabetes. Maintaining ideal glucose levels in diabetes at midlife might prevent later rapid cognitive decline.

Leveraging the future of diagnosis and management of diabetes: From old indexes to new technologies

BACKGROUND

Diabetes is a heterogeneous and multifactorial disease. However, glycemia and glycated hemoglobin have been the focus of diabetes diagnosis and management for the last decades. As diabetes management goes far beyond glucose control, it has become clear that assessment of other biochemical parameters gives a much wider view of the metabolic state of each individual, enabling a precision medicine approach.

METHODS

In this review, we summarize and discuss indexes that have been used in epidemiological studies and in the clinical practice.

RESULTS

Indexes of insulin secretion, sensitivity/resistance and metabolism have been developed and validated over the years to account also with insulin, C-peptide, triglycerides or even anthropometric measures. Nevertheless, each one has their own objective and consequently, advantages and disadvantages for specific cases. Thus, we discuss how new technologies, namely new sensors but also new softwares/applications, can improve the diagnosis and management of diabetes, both for healthcare professionals but also for caretakers and, importantly, to promote the empowerment of people living with diabetes.

CONCLUSIONS

In long-term, the solution for a better diabetes management would be a platform that allows to integrate all sorts of relevant information for the person with diabetes and for the healthcare practitioners, namely glucose, insulin and C-peptide or, in case of need, other parameters/indexes at home, sometimes more than once a day. This solution would allow a better and simpler disease management, more adequate therapeutics thereby improving patients' quality of life and reducing associated costs.

Pretransplant evaluation and the risk of glucose metabolic alterations after renal transplantation: a prospective study

BACKGROUND

Post-transplant prediabetes (PreDM) and diabetes (PTDM) are common and have an impact on cardiovascular events. We sought to investigate the pathogenesis and best approach for prediction.

METHODS

We prospectively studied 115 waitlisted patients from a single center without manifest diabetes. An oral glucose tolerance test (OGTT) was performed yearly until transplantation and 12 months later. Insulin secretion, insulin sensitivity (IS) and disposition index (DI) were derived from the OGTT.

RESULTS

PreDM and PTDM were observed in 27% and 28.6% of patients, respectively. Pretransplant age, body mass index (BMI), 120 min glucose, IS, DI, and prediabetes or undiagnosed diabetes were significantly associated with these alterations. In multivariate analysis, pretransplant age [odds ratio (OR) 1.5; 95% confidence interval (CI) 1.04-2.1], BMI (OR 1.16; 95% CI 1.04-1.3) and cumulative steroids (OR 1.5; 95% CI 1.02-2.2) were predictors of PreDM or PTDM. Receiver operating characteristic curve analysis showed that pretransplant BMI and 120 min glucose had the highest area under the curve (0.72; 95% CI 0.62-0.8; and 0.69; 95% CI 0.59-0.79, respectively). The highest discrimination cut-off for BMI (≥28.5 kg/m2) and 120 min glucose (≥123.5 mg/dL) yielded a similar number needed to diagnose (2.5).

CONCLUSIONS

PreDM or PTDM develops in waitlisted patients with an ineffective insulin secretion and BMI shows a similar diagnostic capacity to OGTT. Pretransplant interventions may reduce post-transplant glucose alterations.

Time-restricted eating did not alter insulin sensitivity or β-cell function in adults with obesity: A randomized pilot study

OBJECTIVE

Decreased insulin sensitivity and impairment of β-cell function predate and predict development of type 2 diabetes mellitus. Time-restricted eating (TRE) might have a benefit for these parameters. The objective of this pilot study was to investigate this possibility.

METHODS

Secondary analysis of a randomized controlled trial comparing 12 weeks of TRE (8-hour eating window) to unrestricted eating (non-TRE) was performed. Participants were adults with overweight or obesity and without diabetes. Two-hour oral glucose tolerance testing was performed at baseline and end-intervention. Glucose tolerance test-derived measures of insulin sensitivity, insulin secretion, and β-cell function were compared between groups.

RESULTS

Participants (17 women/3 men with mean [SD] age 45.5 [12.1] years and BMI 34.1 [7.5] kg/m2 ) with a prolonged eating window (15.4 [0.9] hours) were randomized to TRE (n = 11) or non-TRE (n = 9). The quantitative insulin sensitivity check index (QUICKI), Stumvoll index, Avignon index, insulinogenic index, insulin area under the curve/glucose area under the curve, and oral disposition index did not differ between the TRE and non-TRE groups at end-intervention.

CONCLUSIONS

In adults with overweight or obesity and without diabetes, TRE did not significantly alter insulin sensitivity, insulin secretion, or β-cell function over a 12-week intervention. Whether TRE is beneficial in adults with prediabetes or type 2 diabetes mellitus warrants further investigation.

Pilot Trial on the Effect of 5-Aminolevulinic Acid on Glucose Tolerance in Patients with Maternally Inherited Diabetes and Deafness

INTRODUCTION

The amino acid 5-aminolevulinic acid (5-ALA) is the first heme biosynthetic precursor. The combination of 5-ALA with sodium ferrous citrate (SFC) enhances heme production, leading to increased adenosine triphosphate (ATP) production in mitochondria. We investigated whether administering 5-ALA/SFC improves glucose tolerance with an increase in insulin secretion in patients with maternally inherited diabetes and deafness (MIDD), which is characterized by an insulin secretory disorder due to impaired mitochondrial ATP production.

METHODS

This was a single-arm, open-label, interventional study. We prospectively administered the oral glucose tolerance test (OGTT) twice in five patients with MIDD who had received intensive insulin therapy: before and 24 weeks after an administration of 5-ALA/SFC (200/232 mg per day). We measured the concentrations of glucose, insulin, C-peptide, and proinsulin at fasting, and 30, 60, and 120 min after glucose load in each OGTT. The primary endpoint was the changes in the area under the curve (AUC) of serum insulin from 0 to 120 min during OGTT from baseline to 24 weeks.

RESULTS

The serum insulin AUC (µU/mL) during the 120-min OGTT tended to increase from baseline to 24 weeks but not significantly (17.1 ± 13.7 versus 22.3 ± 13.4, p = 0.077). The plasma glucose AUC (mg/dL) during the 120-min OGTT at 24 weeks was not significantly decreased; the late phase of glucose excursion from 60 to 120 min was significantly decreased compared with baseline (357 ± 42 versus 391 ± 50, p = 0.041). The mean level of glycated hemoglobin (HbA1c) decreased from 8.3 ± 1.2% at baseline to 7.9 ± 0.3% at 24 weeks (p = 0.36) without increasing the daily dose of insulin injections.

CONCLUSION

The 24-week administration of 5-ALA/SFC did not demonstrate a significant improvement in insulin secretion in patients with MIDD. Further investigations with a larger number of patients and a placebo control group are required to clarify the potential efficacy of 5-ALA/SFC for ameliorating mitochondrial dysfunctions in MIDD.

TRIAL REGISTRATION

UMIN-CTR000040581 and jRCT071200025.

Metabolic Dysregulation in Adult Survivors of Pediatric Hematopoietic Stem Cell Transplantation: The Role of Incretins

CONTEXT

Survivors of pediatric hematopoietic stem cell transplantation (HSCT) have increased risk of developing metabolic syndrome (MetS), but the mechanisms are poorly understood.

OBJECTIVE

We aimed to test the hypothesis that insufficient secretion of glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) plays a pathogenetic role in HSCT survivors with MetS.

METHODS

This cross-sectional cohort study, conducted at the Danish national referral center for HSCT, studied 42 male HSCT survivors (median age 28.9 years) for a median 21.2 years from HSCT, along with 15 age- and sex-matched healthy controls. Main outcome measures were glucose metabolism and incretin hormones (by oral glucose tolerance test [OGTT]) and MetS criteria. The hypothesis was formulated before data collection.

RESULTS

GLP-1, GIP, and glucagon during an OGTT were similar in patients and controls, with no overall difference between survivors with (24%) and without MetS. However, fasting glucagon was significantly higher in patients with hypertriglyceridemia (mean difference [MD]: 6.1 pmol/L; 95% CI, 1.5-10.8; P = 0.01), and correlated with HDL (MD: 4.7 mmol/L; 95% CI, -0.6 to 9.9; P = 0.08), android-gynoid ratio (correlation coefficient [r] = 0.6, P = 0.0001) and waist-hip ratio (r = 0.5, P = 0.002). A similar pattern was seen for GIP, correlating positively with triglyceride (MD: 60%; 95% CI, 44-82; P = 0.002). GIP levels were significantly increased in patients treated with total body irradiation (TBI) (MD: 165%; 95% CI, 118-230; P = 0.004), which was found to be a significant risk factor for MetS.

CONCLUSION

This study demonstrates an altered production of incretin hormones in HSCT survivors previously treated with TBI, developing dyslipidemia and abdominal adiposity.

Targeted proteomics identifies potential biomarkers of dysglycaemia, beta cell function and insulin sensitivity in Black African men and women

AIMS/HYPOTHESIS

Using a targeted proteomics approach, we aimed to identify and validate circulating proteins associated with impaired glucose metabolism (IGM) and type 2 diabetes in a Black South African cohort. In addition, we assessed sex-specific associations between the validated proteins and pathophysiological pathways of type 2 diabetes.

METHODS

This cross-sectional study included Black South African men (n=380) and women (n=375) who were part of the Middle-Aged Soweto Cohort (MASC). Dual-energy x-ray absorptiometry was used to determine fat mass and visceral adipose tissue, and fasting venous blood samples were collected for analysis of glucose, insulin and C-peptide and for targeted proteomics, measuring a total of 184 pre-selected protein biomarkers. An OGTT was performed on participants without diabetes, and peripheral insulin sensitivity (Matsuda index), HOMA-IR, basal insulin clearance, insulin secretion (C-peptide index) and beta cell function (disposition index) were estimated. Participants were classified as having normal glucose tolerance (NGT; n=546), IGM (n=116) or type 2 diabetes (n=93). Proteins associated with dysglycaemia (IGM or type 2 diabetes) in the MASC were validated in the Swedish EpiHealth cohort (NGT, n=1706; impaired fasting glucose, n=550; type 2 diabetes, n=210).

RESULTS

We identified 73 proteins associated with dysglycaemia in the MASC, of which 34 were validated in the EpiHealth cohort. Among these validated proteins, 11 were associated with various measures of insulin dynamics, with the largest number of proteins being associated with HOMA-IR. In sex-specific analyses, IGF-binding protein 2 (IGFBP2) was associated with lower HOMA-IR in women (coefficient -0.35; 95% CI -0.44, -0.25) and men (coefficient -0.09; 95% CI -0.15, -0.03). Metalloproteinase inhibitor 4 (TIMP4) was associated with higher insulin secretion (coefficient 0.05; 95% CI 0.001, 0.11; p for interaction=0.025) and beta cell function (coefficient 0.06; 95% CI 0.02, 0.09; p for interaction=0.013) in women only. In contrast, a stronger positive association between IGFBP2 and insulin sensitivity determined using an OGTT (coefficient 0.38; 95% CI 0.27, 0.49) was observed in men (p for interaction=0.004). A posteriori analysis showed that the associations between TIMP4 and insulin dynamics were not mediated by adiposity. In contrast, most of the associations between IGFBP2 and insulin dynamics, except for insulin secretion, were mediated by either fat mass index or visceral adipose tissue in men and women. Fat mass index was the strongest mediator between IGFBP2 and insulin sensitivity (total effect mediated 40.7%; 95% CI 37.0, 43.6) and IGFBP2 and HOMA-IR (total effect mediated 39.1%; 95% CI 31.1, 43.5) in men.

CONCLUSIONS/INTERPRETATION

We validated 34 proteins that were associated with type 2 diabetes, of which 11 were associated with measures of type 2 diabetes pathophysiology such as peripheral insulin sensitivity and beta cell function. This study highlights biomarkers that are similar between cohorts of different ancestry, with different lifestyles and sociodemographic profiles. The African-specific biomarkers identified require validation in African cohorts to identify risk markers and increase our understanding of the pathophysiology of type 2 diabetes in African populations.

Exenatide challenge in oral glucose tolerance test is insufficient for predictions of glucose metabolism and insulin secretion after sleeve gastrectomy (SG) in obese patients with type 2 diabetes: a pilot study to establish a preoperative model to estimate β-cell function following augmented glucagon-like peptide-1 secretion after SG

The postoperative increase in glucagon-like peptide-1 (GLP-1) is the main factor to improve glucose metabolism following sleeve gastrectomy (SG) in obese patients with type 2 diabetes. We investigated whether the β-cell responsiveness to an injection of exogenous GLP-1 in the preoperative period could determine the postoperative glucose tolerance in 18 patients underwent SG. In the preoperative period, a regular oral glucose tolerance test (OGTT) and an exenatide-challenge during OGTT (Ex-OGTT) were performed to evaluate the β-cell function and its responsiveness to GLP-1. The postoperative glucose tolerance was evaluated by another regular OGTT performed at 3 months after SG. The significant decrease in glucose levels with enhanced secretions of insulin and GLP-1 was observed in OGTT at 3 months after SG. The area under the curve of glucose from 0 to 120 minutes (AUC glucose_{0-120 min}) and the insulinogenic index (I.I.) in OGTT at 3 months post-SG were significantly improved compared to those in preoperative period, but comparable with those in Ex-OGTT. AUC glucose_{0-120 min} and I.I. in OGTT at 3 months post-SG were significantly correlated with not only those in Ex-OGTT, but also those in the preoperative regular OGTT. Conversely, the correlations calculated by the Spearman's ρ were stronger in the latter than the former. This exenatide-challenge protocol might be useful to estimate glucose tolerance and insulin secretion after SG, however, it may be insufficient to improve predictability of a patient who is likely to achieve a significant benefit on glucose metabolism from receiving SG.

Effects of Roux-en-Y Gastric Bypass and Sleeve Gastrectomy on β-Cell Function at 1 Year After Surgery: A Systematic Review

Bariatric surgery is a highly effective obesity treatment resulting in substantial weight loss and improved glucose metabolism. We hereby aimed to summarize available evidence of the effect of the 2 most common bariatric surgery procedures, Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG), on dynamic measures of β-cell function (BCF). A systematic search of the literature was conducted in 3 bibliographic databases for studies reporting effects of RYGB and/or SG on BCF assessed using dynamic metabolic perturbation (oral or intravenous bolus stimulation), performed before and 1 year (±3 months) after surgery. Twenty-seven unique studies (6 randomized controlled trials and 21 observational studies), involving a total of 1856 obese adults, were included for final analysis. Twenty-five and 9 studies report effects of RYGB and SG on BCF, respectively (7 studies compared the 2 procedures). Seven studies report results according to presurgical diabetes status. Owing to variable testing procedures and BCF indices reported, no meta-analysis was feasible, and data were summarized qualitatively. For both surgical procedures, most studies suggest an increase in BCF and disposition index, particularly when using oral stimulation, with a more pronounced increase in diabetic than nondiabetic individuals. Additionally, limited indications for greater effects after RYGB versus SG were found. The quality of the included studies was, in general, satisfactory. The considerable heterogeneity of test protocols and outcome measures underscore the need for a harmonization of BCF testing in future research.

Effects of a low-carbohydrate/high-protein diet on metabolic health in individuals with chronic spinal cord injury: An exploratory analysis of results from a randomized controlled trial

We explored the impact of a low-carbohydrate/high-protein diet (LC/HP, ~30% energy from protein, 40% energy from carbohydrate) on indices of metabolic function and body composition in individuals with chronic spinal cord injury (SCI). Adults with SCI (≥3 years post-injury, C4-L2, AIS A-D) and insulin resistance or pre-diabetes were randomly assigned to an 8-week iso-caloric LC/HP diet group (n = 11) or control group (n = 14). All LC/HP meals were delivered weekly to participants' homes, and participants in the control group consumed their habitual diet. Each participant underwent an oral glucose tolerance test (OGTT) to assess glucose tolerance, insulin, area under the curve (AUC) for glucose and insulin, Matsuda Index, glucose-stimulated insulin secretion (GSIS), disposition index, and hepatic insulin extraction (HIE). Fasting blood lipid and inflammation were assessed, and body composition was estimated using dual-energy x-ray absorptiometry. A linear mixed model was used to evaluate the main effect of diet, time, and their interaction. Compared to the control group, participants in the LC/HP group had reduced total body fat mass (LC/HP: -5.9%, Control: 0.7%), visceral fat mass (LC/HP: -16.2%, Control: 5.2%), total- (LC/HP: -20.1, Control: 3.7 mg/dl), and LDL-cholesterol (LC/HP: -13.9, Control: 3.1 mg/dl) (pdiet*time  < 0.05 for all). Regardless of group, AUCinsulin and peak insulin during the OGTT decreased, and HIE increased over time (ptime  < 0.05). A trend for diet*time interaction was observed for glucoseOGTT120min (LC/HP: -20.7, Control: 3.0 mg/dl, pdiet*time  = 0.09) and peak C-peptide (LC/HP: -2.1, Control: 0.0 ng/ml, pdiet*time  = 0.07). HDL-cholesterol, lean body mass, Matsuda Index, fasting glucose, insulin, insulinOGTT120min , AUCglucose , pancreatic beta cell function (GSIS, disposition index), and inflammation (C-reactive protein, IL-6, IL-8, IL-10, TNF-α) did not change over time. In conclusion, our results suggest that individuals with SCI and insulin resistance may adopt an LC/HP diet to improve body composition and lipid profiles. Its impact on glucose metabolism and inflammation remains inconclusive and warrants future investigations.

Incidence and status of insulin secretion in pregnant women with flat plasma glucose profiles during oral glucose tolerance test

OBJECTIVES

Flat shaped glucose curves (FC) during oral glucose tolerance test (OGTT) in pregnant women (PW) are a not uncommon finding. We aimed to define the FC incidence in a large PW cohort and to describe the status of insulin and C-peptide secretion in women with FC when compared with a well-matched control group.

METHODS

1050 PW performing OGTT for gestational diabetes screening were enrolled. An increase <6 % in plasma glucose (PG) during OGTT defined a FC. Serum samples for measuring insulin and C-peptide were also obtained.

RESULTS

61 (5.8 %) women showed a FC. 60 of them, paired to a group of 60 no-FC women matched for age, body mass index and gestational age, were further investigated. C-peptide and insulin concentrations were significantly lower (P < 0.001) in FC in both 1-h and 2-h OGTT samples. When incremental area under the curves (AUC) normalized to PG were estimated, only AUCinsulin remained however significantly lower. The insulin sensitivity index was higher in FC.

CONCLUSIONS

PW with FC showed a hypersensitivity to insulin with normal β-cell function. Moreover, a delayed glucose absorption could be hypothesised because of the slight but continuously increasing shape of insulin curve found in FC group. Both phenomena could occur in parallel and contribute to FC.

Phase 2 trial with imeglimin in patients with Type 2 diabetes indicates effects on insulin secretion and sensitivity

INTRODUCTION

The aim of the present study was to evaluate the effect of 18-week monotherapy with imeglimin on glucose tolerance and on insulin secretion/sensitivity in type 2 diabetic (T2D) patients.

METHODS

The study was an 18-week, double-blind clinical trial in T2D subjects previously treated with stable metformin therapy and washed out for 4 weeks. Subjects were randomized 1:1 to receive a 1500 mg bid of imeglimin or placebo. The primary endpoint was the effect of imeglimin vs placebo on changes from baseline to week 18 in glucose tolerance (glucose area under the curve [AUC]) during a 3 h-glucose tolerance test [OGTT]). Secondary endpoints included glycaemic control and calculated indices of insulin secretion and sensitivity.

RESULTS

A total of 59 subjects were randomized, 30 receiving imeglimin and 29 receiving placebo. The study met its primary endpoint. Least squares (LS) mean difference between treatment groups (imeglimin - placebo) for AUC glucose from baseline to week 18 was -429.6 mmol/L·min (p = .001). Two-hour post-dose fasting plasma glucose was significantly decreased with LS mean differences of -1.22 mmol/L (p = .022) and HbA1c was improved with LS mean differences of -0.62% (p = .013). The AUC_0-180min ratio C-peptide/glucose [LS mean differences of 0.041 nmol/mmol (p < .001)] and insulinogenic index were significantly increased by imeglimin treatment. The increase in insulin secretion was associated with an increase in beta-cell glucose sensitivity. Additionally, the insulin sensitivity indices derived from the OGTT Stumvoll (p = .001) and Matsuda (not significant) were improved in the imeglimin group vs placebo. Imeglimin was well tolerated with 26.7% of subjects presenting at least one treatment-emergent adverse event versus 58.6% of subjects in the placebo group.

CONCLUSIONS

Results are consistent with a mode of action involving insulin secretion as well as improved insulin sensitivity and further support the potential for imeglimin to improve healthcare in T2D patients.

Endogenous GLP-1 levels play an important role in determining the efficacy of DPP-IV Inhibitors in both prediabetes and type 2 diabetes

Background

In contrast to Western population, glucagon-like peptide-1 (GLP-1) levels are preserved in some East Asian population with type 2 diabetes (T2D), explaining why dipeptidyl peptidase-IV (DPP-IV) inhibitors are more effective in East Asians. We assessed whether differences in endogenous GLP-1 levels resulted in different treatment responses to DPP-IV inhibitors in prediabetes and T2D.

Methods

A prospective 12-week study using linagliptin 5mg once daily in 50 subjects (28 prediabetes and 22 T2D) who were stratified into high versus low fasting GLP-1 groups. A 75-g oral glucose tolerance test (OGTT) was performed at week 0 and 12. Primary outcomes were changes in HbA1c, fasting and post-OGTT glucose after 12 weeks. Secondary outcomes included changes in insulin resistance and beta cell function indices.

Results

There was a greater HbA1c reduction in subjects with high GLP-1 compared to low GLP-1 levels in both the prediabetes and T2D populations [least-squares mean (LS-mean) change of -0.33% vs. -0.11% and -1.48% vs. -0.90% respectively)]. Linagliptin significantly reduced glucose excursion by 18% in high GLP-1 compared with 8% in low GLP-1 prediabetes groups. The reduction in glucose excursion was greater in high GLP-1 compared to low GLP-1 T2D by 30% and 21% respectively. There were significant LS-mean between-group differences in fasting glucose (-0.95 mmol/L), 2-hour glucose post-OGTT (-2.4 mmol/L) in the high GLP-1 T2D group. Improvement in insulin resistance indices were seen in the high GLP-1 T2D group while high GLP-1 prediabetes group demonstrated improvement in beta cell function indices. No incidence of hypoglycemia was reported.

Conclusions

Linagliptin resulted in a greater HbA1c reduction in the high GLP-1 prediabetes and T2D compared to low GLP-1 groups. Endogenous GLP-1 level play an important role in determining the efficacy of DPP-IV inhibitors irrespective of the abnormal glucose tolerance states.