Glucose Disposal Research Articles

9227 Haptoglobin-related protein (HPR) new role as insulin secretion enhancer

Abstract Disclosure: Carlos Viesi, Ph.D.[1], Ian Tamburini, BS[1], Hosung Bae, Ph.D[1]., Erwin Ilegems, Ph.D.[2], Leandro Velez, Ph.D. [1], Mingqi Zhou, BS[1], Christy Nguyen, Ph.D.[1], Casey Johnson, Ph.D.[1], Cholsoon Jang, Ph.D[1]., Erika Nishimura[2] and Marcus Seldin, Ph.D.[1]. [1]Department of Biological Chemistry, Center for Epigenetics and Metabolism, University of California, Irvine, CA, USA, [2]Departments of Diabetes Protein Engineering, Diabetes Biology & Pharmacology, Medicinal Chemistry, Protein Engineering, Novo Nordisk A/S, Novo Nordisk Park, DK-2760 Måløv, Denmark. Type 2 Diabetes (T2D) affects over 530 million people around the globe. Insulin resistance, encompassing tissues such as muscle, adipose, and liver, is the initial step hallmarked by hyperinsulinemia. Coupled with β-cell failure, these coordinated responses progress to T2D, becoming irreversible and medically challenging. Despite the well-established requirement for communication between pancreas and peripheral tissues in T2D progression, this area remains almost entirely unexplored. Here, we performed a human population genetic screening across 310 individuals to search for new endocrine regulators of pancreas function. Specifically, global gene expression from 18 peripheral tissues was analyzed to identify potential endocrine regulators of insulin secretion. This analysis prioritized liver-specific Haptoglobin-related protein (HPR) as genetically-enriched with islet insulin responses. Mouse models using AAV technology and acute protein administration of HPR showed that this newly secreted protein is sufficient to prevent diet-induced insulin resistance through enhanced beta-cell respiration. When mice were administered soluble HPR, then pancreatic tissue subjected to global RNA-sequencing, enhanced respiration pathways were observed. Next, we generated hepatocyte-specific overexpression models using AAV, which were sufficient to rescue whole-body glucose disposal profiles and weight gain in diet-induced insulin-resistant mice. Altogether, these findings highlight HPR as a novel soluble protein which signals from liver to pancreatic islets. Presentation: 6/3/2024

8258 Haptoglobin-related protein (HPR) new role as insulin secretion enhancer

Abstract Disclosure: C. Viesi: None. Type 2 Diabetes (T2D) affects over 530 million people around the globe. Insulin resistance, encompassing tissues such as muscle, adipose, and liver, is the initial step hallmarked by hyperinsulinemia. Coupled with β-cell failure, these coordinated responses progress to T2D, becoming irreversible and medically challenging. Despite the well-established requirement for communication between pancreas and peripheral tissues in T2D progression, this area remains almost entirely unexplored. Here, we performed a human population genetic screening across 310 individuals to search for new endocrine regulators of pancreas function. Specifically, global gene expression from 18 peripheral tissues was analyzed to identify potential endocrine regulators of insulin secretion. This analysis prioritized liver-specific Haptoglobin-related protein (HPR) as genetically-enriched with islet insulin responses. Mouse models using AAV technology and acute protein administration of HPR showed that this newly secreted protein is sufficient to prevent diet-induced insulin resistance through enhanced beta-cell respiration. When mice were administered soluble HPR, then pancreatic tissue subjected to global RNA-sequencing, enhanced respiration pathways were observed. Next, we generated hepatocyte-specific overexpression models using AAV, which were sufficient to rescue whole-body glucose disposal profiles and weight gain in diet-induced insulin-resistant mice. Altogether, these findings highlight HPR as a novel soluble protein which signals from liver to pancreatic islets. Presentation: 6/3/2024

A 3-Week Ketogenic Diet Increases Skeletal Muscle Insulin Sensitivity in Individuals With Obesity: A Randomized Controlled Crossover Trial.

A ketogenic diet (KD) can induce weight loss and improve glycemic regulation, potentially reducing the risk of developing type 2 diabetes. To elucidate the underlying mechanisms behind these beneficial effects of a KD, we investigated the impact of a KD on organ-specific insulin sensitivity (IS) in skeletal muscle, liver, and adipose tissue. We hypothesized that a KD would increase IS in skeletal muscle. The study included 11 individuals with obesity who underwent a randomized, crossover trial with two three-week interventions: 1) KD and 2) standard diet. Skeletal muscle IS was quantified as the increase in glucose disposal during a hyperinsulinemic-euglycemic clamp (HEC). Hepatic IS and adipose tissue IS were quantified as the relative suppression of endogenous glucose production (EGP) and the relative suppression of palmitate flux during the HEC. The KD led to a 2.2 kg weight loss, increased insulin-stimulated glucose disposal, whereas the relative suppression of EGP during the HEC was similar. In addition, the KD decreased insulin-mediated suppression of lipolysis. In conclusion, a KD increased skeletal muscle IS in individuals with obesity.

Total Body Fat Mass in Relation to Insulin Resistance in Type 1 Diabetic Patients

Abstract Background The introduction of intensive insulin therapy improved glycemic control among people with type 1 diabetes (T1DM). However, an increased prevalence of obesity occurred in those with T1DM with increased insulin resistance. Aim to determine the relationship between total body fat with each of glycemic control and insulin resistance among children with T1DM. Methodology Hundred twenty children with T1DM aged 10-18 years were recruited from the Pediatric and Adolescent Diabetes Unit (PADU), Ain Shams University. They were assessed for insulin requirements, fasting lipids profile, glycated hemoglobin (HbA1c%) and bio- impedence to assess total fat mass with calculation of the estimated glucose disposal rate (eGDR) for insulin resistance. Results The body mass index Z score of the studied children with T1DM was 0.6 (0 – 1.2) and their mean HbA1c% was 9.14±1.99%. Children with T1DM having insulin resistance had significantly higher BMI z score, insulin dose, LDL level and total body fat than those without (p = 0.024, p = 0.005, P = 0.009 and p = 0.007, respectively). Total body fat was significantly correlated with duration of diabetes (p < 0.001), BMI z score (p < 0.001) and eGDR (p = 0/009) among the studied children with T1DM. eGDR significantly correlated with both total and visceral fat (P = 0.009 and P = 0.007 respectively) in the studied children and adolescents with T1DM. Conclusion T1DM children having insulin resistance had significantly higher total body fat than those without insulin resistance.

Associations Between Insulin Stimulated Glucose Disposal, Physical Activity, Adiposity, And Fitness In Healthy Adolescents

Associations Between Insulin Stimulated Glucose Disposal, Physical Activity, Adiposity, And Fitness In Healthy Adolescents

Correlation between triglyceride-glucose index and diabetic kidney disease risk in adults with type 1 diabetes mellitus

BackgroundThe triglyceride-glucose (TyG) index is identified as an alternative indicator of insulin resistance (IR) and is associated with macro- and micro-vascular diseases among patients with type 2 diabetes mellitus. The relationship between the TyG index and IR and its impact on diabetic kidney disease (DKD) remains unclear among adults with type 1 diabetes mellitus(T1DM).MethodsThis study comprised a cross-sectional analysis using data from the Guangdong T1DM Translational Medicine Study (GTT) and a longitudinal analysis using data from the type 1 diabetes (T1D) Exchange registry study. Correlation analysis was used to investigate the association between the TyG index and IR. Logistic regression and Cox proportional hazards regression were performed to explore the impact of the TyG index on DKD risk.ResultsThe GTT Study included 836 adults (216 with DKD and 620 without DKD). A significant correlation existed between the TyG index and the estimated glucose disposal rate (r=-0.64, p < 0.01). The TyG index was a risk factor for DKD after confounder adjustment (OR = 1.34, 95% CI:1.03–1.74). The T1D Exchange registry study included 8,771 adults (2,050 with DKD and 6,721 without DKD). After adjusting confounding factors, the TyG index was identified as an independent risk factor for DKD at enrollment, with the highest risk of DKD incidence observed in the highest TyG tertile group (OR = 1.92, 95%CI:1.67–2.20). During a median follow-up of 44.58(21.84, 67.09) months, the risk of developing DKD was increased by 32% at every 1 SD increase of the TyG index over time among participants without DKD at enrollment.ConclusionsThe TyG index could be used to assess IR and was identified as an independent risk factor of DKD among adults with T1DM.

Insulin resistance assessed by estimated glucose disposal rate and risk of atherosclerotic cardiovascular diseases incidence: the multi-ethnic study of atherosclerosis

BackgroundTo investigate the relationship between estimated glucose disposal rate (eGDR), a surrogate indicator of insulin resistance, and atherosclerotic cardiovascular diseases (ASCVD) incidence risk.MethodsThis prospective cohort study utilized data from the 6026 participants from the Multi-Ethnic Study of Atherosclerosis. The eGDR (mg/kg/min) was computed as 21.158 − (0.09 × waist circumference [cm]) − (3.407 × hypertension [yes/no]) − (0.551 × HbA1c [%]). The population was categorized into four subgroups according to the quartiles (Q) of eGDR. Cox proportional hazard models were applied to assess the associations between eGDR and ASCVD incidence, and restricted cubic spine (RCS) was employed to examine the dose–response relationship.ResultsThe mean age of participants was 63.6 ± 10.1 years, comprising 3163 (52.5%) women. Over a median follow-up duration of 14.1 years, 565 (9.4%) developed ASCVD, including 256 (4.2%) myocardial infarctions, 234 (3.9%) strokes, and 358 (5.9%) fatal coronary heart disease. Compared to the lowest quartile, the adjusted hazard ratios (95% confidence intervals) for incident ASCVD for Q2–Q4 were 0.87 (0.68−1.10), 0.63 (0.47−0.84), and 0.43 (0.30−0.64), respectively. Per 1 standard deviation increase in eGDR was associated with a 30% (HR: 0.70, 95% CI 0.60−0.80) risk reduction of ASCVD, with the subgroup analyses indicating that age and hypertension modified the association (P for interaction < 0.05). RCS analysis indicated a significant and linear relationship between eGDR and ASCVD incidence risk.ConclusioneGDR level was negatively associated with incident ASCVD risk in a linear fashion among the general population. Our findings may contribute to preventive measures by improving ASCVD risk assessment.

Estimated glucose disposal rate for predicting cardiovascular events and mortality in patients with non-diabetic chronic kidney disease: a prospective cohort study

BackgroundEvidence suggests that insulin resistance (IR) is an autonomous risk factor for cardiovascular disease (CVD). Nevertheless, the association between estimated glucose disposal rate (eGDR), a novel indicator of IR, and incident CVD and mortality in chronic kidney disease (CKD) patients without diabetes remains uncertain.MethodsThe study included 19,906 participants from the UK Biobank who had an estimated glomerular filtration rate (eGFR) < 60 ml/min/1.73m2 or a urinary albumin-to-creatinine ratio (UACR) ≥ 30 mg/g and no history of CVD and diabetes. Individuals were divided into three categories based on tertiles of eGDR. The outcome was a composite CVD (coronary heart disease (CHD) and stroke) and mortality (all-cause, non-accidental, and cardiovascular mortality). Furthermore, a cohort of 1,600 individuals from the US National Health and Nutrition Examination Survey (NHANES) was applied to validate the association between eGDR and mortality. The Cox proportional hazards regression models were used to examine the association between eGDR and event outcomes.ResultsDuring a follow-up of around 12 years, 2,860 CVD, 2,249 CHD, 783 stroke, 2,431 all-cause, 2,326 non-accidental and 492 cardiovascular deaths were recorded from UK Biobank. Higher eGDR level was not only associated with lower risk of CVD (hazard ratio [HR] 0.641, 95% confidence interval [CI] 0.559–0.734), CHD (HR 0.607, 95% CI 0.520–0.709), stroke (HR 0.748, 95% CI 0.579–0.966), but also related to reduced risk of all-cause (HR 0.803, 95% CI 0.698–0.923), non-accidental (HR 0.787, 95% CI 0.682–0.908), and cardiovascular mortality (HR 0.592, 95% CI 0.423–0.829). Validation analyses from NHANES yielded consistent relationship on mortality.ConclusionsIn these two large cohorts of CKD patients without DM, a higher eGDR level was associated with a decreased risk of CVD and mortality.

Morning Engagement of Hepatic Insulin Receptors Improves Afternoon Hepatic Glucose Disposal and Storage.

Glucose tolerance improves significantly upon consuming a second, identical meal later in the day (second meal phenomenon). We previously established that morning hyperinsulinemia primes the liver for increased afternoon hepatic glucose uptake (HGU). Although the route of insulin delivery is an important determinant of the mechanisms by which insulin regulates liver glucose metabolism (direct hepatic vs indirect insulin action), it is not known if insulin's delivery route affects the second meal response. To determine whether morning peripheral insulin delivery (as occurs clinically (subcutaneous)) can enhance afternoon HGU, conscious dogs were treated in the morning with insulin delivered via the portal vein, or peripherally (leg vein), while glucose was infused to maintain euglycemia. Consequently, arterial insulin levels increased similarly in both groups, but relative hepatic insulin deficiency occurred when insulin was delivered peripherally. In the afternoon, all animals were challenged with the same hyperinsulinemic-hyperglycemic clamp to simulate identical postprandial-like conditions. The substantial enhancement of HGU in the afternoon caused by morning portal vein insulin delivery was lost when insulin was delivered peripherally. This indicates that morning insulin does not cause the second meal phenomenon via its indirect actions on the liver, but rather through direct activation of hepatic insulin signaling.

Association between estimated glucose disposal rate and cardiovascular mortality across the spectrum of glucose tolerance in the US population.

To determine if estimated glucose disposal rate (eGDR) can predict cardiovascular disease mortality risk at different levels of glycaemic tolerance. The eGDR levels of 11 656 individuals aged 45-79 years from the National Health and Nutrition Examination Survey cycles 1999 to 2010 were analysed. Associations between eGDR levels and all-cause and cardiovascular mortality were examined using Cox proportional hazards and Fine and Gray models, respectively. After a median follow-up of 12.8 years, a total of 2852 participants died, with 777 of those deaths attributed to cardiovascular causes. When comparing participants with eGDR values of ≤4 mg/kg/min to those with eGDR values falling within the ranges of 4-6, 6-8 and >8 mg/kg/min, it was found that the latter groups exhibited lower hazard ratios for both all-cause mortality (0.61 [0.52-0.72], 0.61 [0.52-0.72] and 0.46 [0.39-0.55]) and cardiovascular mortality (0.44 [0.33-0.57], 0.45 [0.34-0.59] and 0.30 [0.23-0.40]). A U-shaped relationship between eGDR and all-cause mortality was observed, with an inflection point at an eGDR of 9.54 mg/kg/min. In the general population, the association between reduced eGDR and all-cause and cardiovascular mortality was independently significant, contributing to the identification of individuals at high risk for different levels of glucose tolerances.

Physical activity and sedentary behaviour in relation to body composition, estimated insulin sensitivity and arterial stiffness in adults with type 1 diabetes

AimsTo examine the association of daily PA levels and sedentary behaviour with body composition, estimated insulin sensitivity, and arterial stiffness in adults with type 1 diabetes (T1D). MethodsCross-sectional study in adults with T1D (n = 54). PA levels (daily steps, and time in moderate-to-vigorous intensity PA (MVPA)) and sedentary behaviour were measured using accelerometry for 7 days (McRoberts® DynaPort MoveMonitor). Cardiopulmonary exercise test for VO2max. Anthropometrics were collected, and body composition (total and % of fat mass (FMtot, FM%), total and % of lean mass (LMtot, LM%), and estimated visceral adipose tissue (VAT)) volume was assessed with dual energy X-ray-absorptiometry (DXA). Estimates of insulin sensitivity were determined (estimated glucose disposal rate (eGDR) and total daily insulin dose). Arterial stiffness was assessed with carotid-femoral pulse wave velocity (cf-PWV (m/s); SphygmoCor®). ResultsLower 10-years HbA1c associated moderately with all PA measures. Favourable moderate associations were also found between PA measures and BMI, waist, VAT but not FM and LM. PA measures were favourably associated with a lower total daily insulin dose and higher eGDR. All PA parameters associated moderately with cf-PWV however not independent from traditional risk factors. VO2max was inversely associated with cf-PWV independent of age, T1D duration and 24-hour mean blood pressure. ConclusionsHigher levels of PA, lower sedentary behaviour and greater exercise capacity are favourably associated with long-term glycaemic control, body composition, insulin dosage, estimated insulin sensitivity and arterial stiffness in adults with T1D. Therefore, regular PA and limiting sedentary time should be encouraged to improve metabolic and cardiovascular health in this population. Future longitudinal studies should explore mutual interactions and synergistic effects of PA on these outcomes.

Zeaxanthin and Lutein Ameliorate Alzheimer's Disease-like Pathology: Modulation of Insulin Resistance, Neuroinflammation, and Acetylcholinesterase Activity in an Amyloid-β Rat Model.

Alzheimer's disease (AD) is characterized by impaired insulin/insulin-like growth factor-1 signaling in the hippocampus. Zeaxanthin and lutein, known for their antioxidant and anti-inflammatory properties, have been reported to protect against brain damage and cognitive decline. However, their mechanisms related to insulin signaling in AD remain unclear. This study investigated the efficacy and mechanisms of zeaxanthin, lutein, and resveratrol in modulating an AD-like pathology in an amyloid-β rat model. Rats were administered hippocampal infusions of 3.6 nmol/day amyloid-β (Aβ)(25-35) for 14 days to induce AD-like memory deficits (AD-CON). Normal control rats received Aβ(35-25) (Normal-CON). All rats had a high-fat diet. Daily, AD rats consumed 200 mg/kg body weight of zeaxanthin (AD-ZXT), lutein (AD-LTN), and resveratrol (AD-RVT; positive-control) or resistant dextrin as a placebo (AD-CON) for eight weeks. The AD-CON rats exhibited a higher Aβ deposition, attenuated hippocampal insulin signaling (reduced phosphorylation of protein kinase B [pAkt] and glycogen synthase kinase-3β [pGSK-3β]), increased neuroinflammation, elevated acetylcholinesterase activity, and memory deficits compared to the Normal-CON group. They also showed systemic insulin resistance and high hepatic glucose output. Zeaxanthin and lutein prevented memory impairment more effectively than the positive-control resveratrol by suppressing acetylcholinesterase activity, lipid peroxidation, and pro-inflammatory cytokines (TNF-α, IL-1β). They also potentiated hippocampal insulin signaling and increased brain-derived neurotrophic factor (BDNF) and ciliary neurotrophic factor (CTNF) mRNA expression to levels comparable to the Normal-CON rats. Additionally, zeaxanthin and lutein improved glucose disposal, reduced hepatic glucose output, and normalized insulin secretion patterns. In conclusion, zeaxanthin and lutein supplementation at doses equivalent to 1.5-2.0 g daily in humans may have practical implications for preventing or slowing human AD progression by reducing neuroinflammation and maintaining systemic and central glucose homeostasis, showing promise even when compared to the established neuroprotective compound resveratrol. However, further clinical trials are needed to evaluate their efficacy and safety in human populations.

KLF3 impacts insulin sensitivity and glucose uptake in skeletal muscle.

Skeletal muscle is one of the predominant sites involved in glucose disposal, accounting for ∼80% of postprandial glucose uptake, and plays a critical role in maintaining glycemic homeostasis. Dysregulation of energy metabolism in skeletal muscle is involved in developing insulin resistance and type 2 diabetes (T2D). Transcriptomic responses of skeletal muscle to exercise found that the expression of Klf3 was increased in T2D Goto-Kakizaki (GK) rats and decreased after exercise with improved hyperglycemia and insulin resistance, implying that Klf3 might be associated with insulin sensitivity and glucose metabolism. We also found that knockdown of Klf3 promoted basal and insulin-stimulated glucose uptake in L6 myotubes, whereas overexpression of Klf3 resulted in the opposite. Through pairwise comparisons of L6 myotubes transcriptome, we identified 2,256 and 1,988 differentially expressed genes in Klf3 knockdown and overexpression groups, respectively. In insulin signaling, the expression of Slc2a4, Akt2, Insr, and Sorbs1 was significantly increased by Klf3 knockdown and decreased with Klf3 overexpression; Ptprf and Fasn were markedly downregulated in Klf3 reduced group and upregulated in Klf3 overexpressed group. Moreover, downregulation of Klf3 promoted the expression of glucose transporter 4 (GLUT4) and protein kinase B (AKT) proteins, as well as the translocation of GLUT4 to the cell membrane in the basal situation, and enhanced insulin sensitivity, characterized by increased insulin-stimulated GLUT4 translocation and AKT, TBC1 domain family member 1 (TBC1D1) and TBC1 domain family member 4 (TBC1D4) phosphorylation, whereas overexpression of Klf3 showed contrary results. These results suggest that Klf3 affects glucose uptake and insulin sensitivity via insulin signal transduction and intracellular metabolism, offering a novel potential treatment strategy for T2D.NEW & NOTEWORTHY The knockdown of Klf3 increased glucose uptake and improved insulin sensitivity in L6 myotubes, whereas its overexpression had the opposite effect. To explore the underlying mechanisms, we evaluated the transcriptional profiles of L6 myotubes after Klf3 knockdown and overexpression and revealed that metabolism and insulin-related pathways were significantly impacted. Klf3 also influenced the expression or modification of glucose transporter 4 (GLUT4), protein kinase B (AKT), TBC1 domain family member 1 (TBC1D1), and TBC1 domain family member 4 (TBC1D4)in the insulin signaling pathway, affecting insulin sensitivity and glucose uptake.

Glucose Variability in People with Type 1 Diabetes: Associations with Body Weight, Body Composition, and Insulin Sensitivity.

The prevalence of overweight and obesity increases in people with type 1 diabetes (T1D). However, the impact of fat accumulation on glucose dynamics in T1D is poorly understood. We assessed continuous glucose monitoring (CGM) parameters in patients with T1D depending on their body weight, body composition, and insulin sensitivity. In 547 patients, including 238 overweight/obese individuals, CGM-derived time in range (TIR) and glucose variability (GV) were estimated. Body composition was assessed by DXA. Estimated glucose disposal rate (eGDR) was used as an indicator of insulin sensitivity. Overweight/obese patients, when compared to normal-weight ones, have a lower time below range (TBR) (<3 mmol/L), GV, and experienced fewer episodes of low glucose. In men, lower TIR, higher time above range (TAR), and GV reduction were associated with central adiposity assessed by total, trunk, and android fat mass. In women, gynoid fat mass only was associated with a lower TIR and higher TAR. The eGDR was a positive predictor of TIR and a negative predictor of TAR, TBR, and GV in men and women. In conclusion, adiposity in people with T1D is associated with a lower risk of CGM-confirmed hypoglycemia, higher TAR, and reduced GV. These features of daily glucose dynamics may be mediated by insulin resistance.

Illusory movements for immobile patients with extensive burns (IMMOBILE): A randomized, controlled, cross-over trial

IntroductionPatients who have sustained extensive burns frequently exhibit substantial damage to skeletal muscle and associated complications. The rehabilitation of these patients can be challenging due to the nature of the injury and the subsequent complications. Nevertheless, there is a possibility that functional proprioceptive stimulation (illusory movements) may facilitate effective rehabilitation in patients with limited physiotherapy options. Nevertheless, this approach has yet to be tested in patients with burn injuries. Material and methodologyA prospective, randomised, crossover trial was conducted at a burn centre in a tertiary teaching hospital. The objective was to assess the effects of illusory movements on energy metabolism, insulin sensitivity, and skeletal muscle biology in adult critically ill patients with deep burns covering 30 % or more of the total body surface area. Two 30-minute daily sessions of functional proprioceptive stimulation were administered in addition to the standard physical therapy or physical activity regimen. Subsequently, the patients proceeded to the next stage of the trial, which involved a two-week crossover period. Measurements and main resultsDaily indirect calorimetry and calculation of nitrogen balance. Skeletal muscle biopsies from vastus lateralis for high resolution respirometry and euglycemic clamps to assess whole body glucose disposal were performed three times: at baseline and then fortnightly after each intervention period. The intervention was feasible and well tolerated in both early and late stages of burn disease. It did not change energy expenditure (mean change −33 [95 % CI: −292;+227] kcal .24 h−1, p = 0.79), nitrogen balance (+2.0 [95 % CI: −3.1;+7.1] g N .1.73 m−2 BSA .24 h−1), or insulin sensitivity (mean change of insulin-mediated glucose disposal −0.33 [95 % CI: −1.18;+0.53] mmol.h−1). At the cellular level, the intervention increased the capacity of mitochondria to synthesize ATP by aerobic phosphorylation and tended to increase mitochondrial coupling. Functional capacities of fatty acid oxidation and electron transfer chain complexes I, II, and IV were unaffected. ConclusionsCompared to physical therapy alone, two daily sessions of functional proprioceptive stimulation in addition to usual physical therapy in patients with extensive burns did not change energy expenditure, insulin sensitivity, nitrogen balance, or energy substrate oxidation. At cellular level, the intervention improved the capacity of aerobic phosphorylation in skeletal muscle mitochondria. Clinical effects remain to be demonstrated in adequately powered trials.

Impaired insulin sensitivity measured by estimated glucose disposal rate is associated with decreased myocardial mechano-energetic efficiency in non-diabetic individuals

Background and aimsImpaired myocardial mechano-energetic efficiency (MEE) has been associated with cardiac insulin resistance measured by dynamic positron emission tomography (PET) with 18F-fluorodeoxyglucose (18F-FDG) combined with euglycemic–hyperinsulinemic clamp. Estimate glucose disposal rate (eGDR) index has a good correlation with whole-body insulin sensitivity. It remains unsettled whether eGDR index is a suitable proxy of cardiac insulin sensitivity as well as its association with myocardial MEE. The aims of this study were: 1) to compare eGDR index with HOMA-IR, QUICKI and FIRI indexes for association with myocardial glucose metabolic rate (MrGlu); and 2) to determine the association of eGDR index with myocardial MEE. MethodsWe evaluated MrGlu using PET with 18F-FDG combined with euglycemic–hyperinsulinemic clamp in 50 individuals without history of coronary heart disease. Myocardial MEE per gram of left ventricular mass (MEEi) was measured in 1181 subjects by echocardiography. eGDR (mg kg-1/min) was calculated as: 21.158 - (0.09 × waist circumference in cm) - (3.407 × hypertension, 1 = yes 0 = no) - (0.551 × HbA1c%). ResultseGDR index was more strongly associated with myocardial MrGlu than HOMA-IR, QUICKI, and FIRI indexes (r = -0.662, r = -0.492, r = 0.570, and r = -0.492, respectively). Individuals in the lower tertiles of eGDR exhibited a significant reduction of MEEi as compared to those in the highest tertile (P < 0.001). In a stepwise multivariate linear regression analysis eGDR index was the major determinant of MEEi independently of well-established cardio-metabolic risk factors. ConclusionsThese data suggest that the eGDR index may be a useful marker to identifying individuals at high cardiovascular risk.

Insulin sensitivity and skeletal muscle mitochondrial respiration in Black and White women with obesity.

Non-Hispanic black women (BW) have a greater risk of type 2 diabetes (T2D) and insulin resistance (IR) compared to non-Hispanic white women (WW). The mechanisms leading to these differences are not understood, and it is unclear whether synergistic effects of race and obesity impact disease risk. To understand the interaction of race and weight, hepatic and peripheral IR were compared in WW and BW with and without obesity. Hepatic and peripheral IR was measured by a labeled, hyperinsulinemic-euglycemic clamp in BW (n=32) and WW (n=32) with and without obesity. Measurements of body composition, cardiorespiratory fitness, and skeletal muscle (SM) respiration were completed. Data were analyzed by mixed model ANOVA. Subjects with obesity had greater hepatic and peripheral IR and lower SM respiration (P<0.001). Despite 14% greater insulin (P=0.066), BW tended to have lower peripheral glucose disposal (Rd; P=0.062), which was driven by women without obesity (P=0.002). BW had significantly lower glucose production (P=0.005), hepatic IR (P=0.024), and maximal coupled and uncoupled respiration (P<0.001) than WW. Maximal coupled and uncoupled SM mitochondrial respiration was strongly correlated with peripheral and hepatic IR (P<0.01). While BW without obesity had lower Rd than WW, race and obesity did not synergistically impact peripheral IR. Paradoxically, WW with obesity had greater hepatic IR compared to BW. Relationships between SM respiration and IR persisted across a range of body weight. These data provide support for therapies in BW, like exercise, that improve SM mitochondrial respiration to reduce IR and T2D risk.

Prognostic Value of Estimated Glucose Disposal Rate and Systemic Immune-Inflammation Index in Non-Diabetic Patients Undergoing PCI for Chronic Total Occlusion.

Chronic total occlusion (CTO) is a complex lesion of coronary artery disease (CAD) with a detection rate of approximately 25% on coronary angiography. CTO patients generally experience poor quality of life and prognosis. This study aims to evaluate the association between the estimated glucose disposal rate (eGDR), a surrogate marker for insulin resistance (IR), and the prognosis of CTO PCI patients, as well as to investigate the potential role of the systemic immune-inflammation index (SII) in this process. We retrospectively included 1482 non-diabetic patients who underwent successful CTO PCI at Anzhen Hospital between January 2018 and December 2021. The primary endpoint was major adverse cardiovascular events (MACEs). Clinical characteristics, biochemical markers, and interventional records were collected, and the eGDR and SII were calculated. Cox regression, restricted cubic splines (RCSs), receiver operating characteristic (ROC) analysis, and Kaplan-Meier curves were used to assess associations. MACEs occurred in 158 patients (10.67%). Patients with MACEs had lower eGDR and higher SII levels. A high eGDR significantly reduced MACE risk (Q4 vs. Q1: HR 0.06, 95% CI 0.03-0.12), while a high SII increased it (Q4 vs. Q1: HR 3.32, 95% CI 1.78-6.33). The combination of low eGDRs and high SIIs predicted the highest MACE risk (HR 4.36, 95% CI 2.71-6.01). The SII partially mediated the relationship between eGDR and MACEs. A low eGDR and high SII are significant predictors of poor prognosis in non-diabetic CTO PCI patients. Combining the eGDR and the SII provides a comprehensive assessment for better predicting cardiovascular outcomes.

The additive effect of the triglyceride-glucose index and estimated glucose disposal rate on long-term mortality among individuals with and without diabetes: a population-based study

BackgroundThe triglyceride-glucose (TyG) index and estimated glucose disposal rate (eGDR), which are calculated using different parameters, are widely used as markers of insulin resistance and are associated with cardiovascular diseases and prognosis. However, whether they have an additive effect on the risk of mortality remains unclear. This study aimed to explore whether the combined assessment of the TyG index and eGDR improved the prediction of long-term mortality in individuals with and without diabetes.MethodsIn this cross-sectional and cohort study, data were derived from the National Health and Nutrition Examination Survey (NHANES) 2001–2018, and death record information was obtained from the National Death Index. The associations of the TyG index and eGDR with all-cause and cardiovascular mortality were determined by multivariate Cox regression analysis and restricted cubic splines.ResultsAmong the 17,787 individuals included in the analysis, there were 1946 (10.9%) all-cause deaths and 649 (3.6%) cardiovascular deaths during a median follow-up of 8.92 years. In individuals with diabetes, the restricted cubic spline curves for the associations of the TyG index and eGDR with mortality followed a J-shape and an L-shape, respectively. The risk of mortality significantly increased after the TyG index was > 9.04 (all-cause mortality) or > 9.30 (cardiovascular mortality), and after eGDR was < 4 mg/kg/min (both all-cause and cardiovascular mortality). In individuals without diabetes, the association between eGDR and mortality followed a negative linear relationship. However, there was no association between the TyG index and mortality. Compared with individuals in the low TyG and high eGDR group, those in the high TyG and low eGDR group (TyG > 9.04 and eGDR < 4) showed the highest risk for all-cause mortality (hazard ratio [HR] = 1.592, 95% confidence interval [CI] 1.284–1.975) and cardiovascular mortality (HR = 1.683, 95% CI 1.179-2.400) in the overall population. Similar results were observed in individuals with and without diabetes.ConclusionsThere was a potential additive effect of the TyG index and eGDR on the risk of long-term mortality in individuals with and without diabetes, which provided additional information for prognostic prediction and contributed to improving risk stratification.

Applying technologies to simplify strategies for exercise in type 1 diabetes.

Challenges and fears related to managing glucose levels around planned and spontaneous exercise affect outcomes and quality of life in people living with type 1 diabetes. Advances in technology, including continuous glucose monitoring, open-loop insulin pump therapy and hybrid closed-loop (HCL) systems for exercise management in type 1 diabetes, address some of these challenges. In this review, three research or clinical experts, each living with type 1 diabetes, leverage published literature and clinical and personal experiences to translate research findings into simplified, patient-centred strategies. With an understanding of limitations in insulin pharmacokinetics, variable intra-individual responses to aerobic and anaerobic exercise, and the features of the technologies, six steps are proposed to guide clinicians in efficiently communicating simplified actions more effectively to individuals with type 1 diabetes. Fundamentally, the six steps centre on two aspects. First, regardless of insulin therapy type, and especially needed for spontaneous exercise, we provide an estimate of glucose disposal into active muscle meant to be consumed as extra carbohydrates for exercise ('ExCarbs'; a common example is 0.5 g/kg body mass per hour for adults and 1.0 g/kg body mass per hour for youth). Second, for planned exercise using open-loop pump therapy or HCL systems, we additionally recommend pre-emptive basal insulin reduction or using HCL exercise modes initiated 90 min (1-2 h) before the start of exercise until the end of exercise. Modifications for aerobic- and anaerobic-type exercise are discussed. The burden of pre-emptive basal insulin reductions and consumption of ExCarbs are the limitations of HCL systems, which may be overcome by future innovations but are unquestionably required for currently available systems.