Insulin resistance in type 1 diabetes mellitus

Triple threat: how diabetes results in worsened bacterial infections

Diabetes mellitus, characterized by impaired insulin signaling, is associated with increased incidence and severity of infections. Various diabetes-related complications contribute to exacerbated bacterial infections, including hyperglycemia, innate immune cell dysfunction, and infection with antibiotic-resistant bacterial strains. One defining symptom of diabetes is hyperglycemia, resulting in elevated blood and tissue glucose concentrations. Glucose is the preferred carbon source of several bacterial pathogens, and hyperglycemia escalates bacterial growth and virulence. Hyperglycemia promotes specific mechanisms of bacterial virulence known to contribute to infection chronicity, including tissue adherence and biofilm formation. Foot infections are a significant source of morbidity in individuals with diabetes and consist of biofilm-associated polymicrobial communities. Bacteria perform complex interspecies behaviors conducive to their growth and virulence within biofilms, including metabolic cross-feeding and altered phenotypes more tolerant to antibiotic therapeutics. Moreover, the metabolic dysfunction caused by diabetes compromises immune cell function, resulting in immune suppression. Impaired insulin signaling induces aberrations in phagocytic cells, which are crucial mediators for controlling and resolving bacterial infections. These aberrancies encompass altered cytokine profiles, the migratory and chemotactic mechanisms of neutrophils, and the metabolic reprogramming required for the oxidative burst and subsequent generation of bactericidal free radicals. Furthermore, the immune suppression caused by diabetes and the polymicrobial nature of the diabetic infection microenvironment may promote the emergence of novel strains of multidrug-resistant bacterial pathogens. This review focuses on the "triple threat" linked to worsened bacterial infections in individuals with diabetes: (i) altered nutritional availability in diabetic tissues, (ii) diabetes-associated immune suppression, and (iii) antibiotic treatment failure.

Mechanisms of insulin resistance in type 1 diabetes mellitus: A case of glucolipotoxicity in skeletal muscle

Insulin resistance (IR), a hallmark of type 2 diabetes mellitus, develops in a significant number of patients with type 1 diabetes mellitus (T1DM) despite the use of insulin therapy to control glycemia. However, little is currently understood regarding the underlying mechanisms of IR in T1DM, especially within the context of chronic insulin treatment. Recent evidence suggests an important influence of glucolipotoxicity in skeletal muscle on insulin sensitivity in T1DM. Thus, this review summarizes our current knowledge regarding impairments in skeletal muscle lipid, glucose, and oxidative metabolism in the development of IR in insulin-treated T1DM.

Long term administration of thiamine disulfide improves FOXO1/PEPCK pathway in liver to reduce insulin resistance in type 1 diabetes rat model

OBJECTIVE

The main objective of this study was to find if thiamine disulfide (TD) lowers blood glucose level and improves insulin resistance (IR) in liver and muscle in rats with chronic type 1 diabetes (T1DM) using euglycemic-hyperinsulinemic clamp technique.

METHODS

A total of fifty male Wistar rats were assigned to five groups consisted of: non-diabetic control (NDC), diabetic control (DC), diabetic treated with thiamine disulfide (D-TD), diabetic treated with insulin (D-insulin), and diabetic treated with both TD and insulin (D-insulin+TD). Diabetes was induced by a 60 mg/kg dose of streptozotocin. Blood glucose levels, pyruvate tolerance test (PTT), intraperitoneal glucose tolerance test (IPGTT), levels of glycosylated hemoglobin (HbA1c), glucose infusion rate (GIR), liver and serum lipid profiles, liver glycogen stores, liver enzymes ([ALT], [AST]), and serum calcium and magnesium levels. were evaluated. Additionally, gene expression levels of phosphoenolpyruvate carboxykinase (Pepck), forkhead box O1 (Foxo1), and glucose transporter type 4 (Glut4) were assessed in liver and skeletal muscle tissues.

RESULTS

Blood glucose level was reduced by TD treatment. In addition, TyG index, HOMA-IR, serum and liver lipid profiles, HbA1c levels, and expressions of Foxo1 and Pepck genes were decreased significantly (P<0.05) in all the treated groups. However, TD did not influence Glut4 gene expression, but GIR as a critical index of IR were 5.0±0.26, 0.29±0.002, 1.5±0.07, 0.9±0.1 and 1.3±0.1 mg.min-1Kg-1 in NDC, DC, D-TD, D-insulin and D-insulin+TD respectively.

CONCLUSIONS

TD improved IR in the liver primarily by suppressing gluconeogenic pathways, implying the potential use of TD as a therapeutic agent in diabetes.

Emerging Perspectives on the Impact of Diabetes Mellitus and Anti-Diabetic Drugs on Premenstrual Syndrome. A Narrative Review

Diabetes mellitus (DM) and premenstrual syndrome (PMS) are global health challenges. Both disorders are often linked to a range of physical and psychological symptoms that significantly impact the quality of life of many women. Yet, the exact relation between DM and PMS is not clear, and the management of both conditions poses a considerable challenge. In this review, we aimed to investigate the interplay between DM, anti-diabetic drugs, and the different theories and symptoms of PMS. Female sex hormones are implicated in the pathophysiology of PMS and can also impair blood glucose control. In addition, patients with diabetes face a higher susceptibility to anxiety and depression disorders, with a significant number of patients experiencing symptoms such as fatigue and difficulty concentrating, which are reported in patients with PMS as well. Complications related to diabetic medications, such as hypoglycemia (with sulfonylurea) and fluid retention (with thiazolidinediones) may also mediate PMS-like symptoms. DM can, in addition, disturb the normal gut microbiota (GM), with a consequent loss of beneficial GM metabolites that guard against PMS, particularly the short-chain fatty acids and serotonin. Among the several available anti-diabetic drugs, those (1) with an anti-inflammatory potential, (2) that can preserve the beneficial GM, and (3) possessing a lower risk for hypoglycemia, might have a favorable outcome in PMS women. Yet, well-designed clinical trials are needed to investigate the anti-diabetic drug(s) of choice for patients with diabetes and PMS.

People with type 1 diabetes exhibit lower exercise capacity compared to a control population with similar physical activity levels

AIMS

We aimed to assess physical activity (PA) levels, adherence to PA guidelines, and fitness capacity in individuals with type 1 diabetes (T1D) and control population.

METHODS

This cross-sectional study included 232 T1D and 248 controls. PA levels (IPAQ-SF questionnaire), adherence to guidelines (>150 min/week of moderate-to-vigorous PA), fitness capacity (VO2max, maximal incremental test on a cycle ergometer and 1RM test) were assessed, along with other clinical variables.

RESULTS

Total PA levels (T1D 2202 ± 1839 vs. controls 2357 ± 2189 METs/min/week), adherence (T1D 53.1 % vs controls 53.2 %), and sedentariness (T1D 27.3 % vs. controls 25.1 %) were similar between groups. However, participants with T1D exhibited significantly lower levels of VO2max (29.1 ± 10.5 vs. 32.5 ± 11.5 mlO2/kg/min, p < 0.001), work capacity (2.73 ± 1.03 vs. 3 ± 10 W/kg of body weight, p = 0.004) and strength capacity (2.29 ± 0.53 vs. 2.41 ± 0.79 kg/kg body weight in 1RM, p = 0.01) than controls, after adjusting for sex and age.

CONCLUSIONS

Individuals with T1D exhibit lower fitness capacity compared to a control population, regardless of age and sex, even when presenting similar levels of total physical activity and adherence to guidelines.

Effect of metformin adjunct therapy on cardiometabolic parameters in Indian adolescents with type 1 diabetes: a randomized controlled trial

Introduction

Insulin resistance is being increasingly reported in type-1 Diabetes (T1D) and is known to accelerate microvascular complications. The Asian Indian population has a higher risk of double diabetes development compared to Caucasians. Hence, we studied the effect of adding Metformin to standard insulin therapy on glycemic control, insulin sensitivity (IS), cardiometabolic parameters and body composition in Indian adolescents with T1D.

Methods

A Randomized controlled trial was conducted spanning 9 months (Registration number:CTRI/2019/11/022126). Inclusion: Age 10-19 years, T1D duration>1year, HbA1c>8% Exclusion: Uncontrolled vascular complications/comorbidities, Metformin intolerance, concomitant drugs affecting insulin sensitivity. Participants were randomized to Metformin/Placebo (n=41 each) groups and age, sex, duration-matched. Assessments were performed at baseline, 3 and 9 months.

Results

82 participants aged 14.7 ± 3years (40 females) were enrolled, with a mean diabetes duration of 5.2 ± 2.3 years. Over 9 months, HbA1c decreased significantly by 0.8 (95% confidence interval: -1.2 to -0.3) from 9.8 ± 1.8% to 9.1 ± 1.7% on Metformin but remained largely unchanged (difference of 0.2, 95% confidence interval: -0.7 to 0.2) i.e. 9.9 ± 1.6% and 9.7 ± 2.2% on placebo. HbA1c improvement correlated negatively with baseline IS (EGDR:r= -0.3;SEARCH:r = -0.24, p<0.05) implying better HbA1c-lowering in those with decreased initial IS. CGM-based glycemic variability (standard deviation) reduced by 6.3 mg/dL (95% confidence interval: -12.9 to 0.2) from 100.2 ± 19.1 mg/dL to 93.7 ± 19.9 mg/dL in those on Metformin (p=0.05) but not placebo (94.0 ± 20.5; 90.0 ± 22.6 mg/dL). Insulin sensitivity: CACTIexa & SEARCH scores demonstrated no change with Metformin but significant worsening on placebo. Significant increase in LDL-C(42%), total cholesterol(133.6 to 151.1 mg/dL), triglyceride (60.0 to 88.0 mg/dL) and carotid intima-media thickness was noted on placebo but not Metformin. Weight, BMI, fat Z-scores increased significantly on placebo but not Metformin. Adverse events (AE) were minor; AE, compliance and safety parameters were similar between the two groups.

Conclusion

Metformin as an adjunct to insulin in Asian Indian adolescents with T1D demonstrated beneficial effect on glycemic control, glycemic variability, IS, lipid profile, vascular function, weight and body fat, with a good safety profile when administered for 9 months.

A systematic review of the association of Type I diabetes with sensorineural hearing loss

OBJECTIVES

Type 1 diabetes (T1D) has been associated with several comorbidities such as ocular, renal, and cardiovascular complications. However, the effect of T1D on the auditory system and sensorineural hearing loss (SNHL) is still not clear. The aim of this study was to conduct a systematic review to evaluate whether T1D is associated with hearing impairment.

METHODS

The databases PubMed, Science Direct, Scopus, and EMBASE were searched in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) criteria. Three reviewers independently screened, selected, and extracted data. The Joanna Briggs Institute (JBI) Critical Appraisal Tools for Analytical cross-sectional and case-control studies were used to perform quality assessment and risk of bias analysis on eligible studies.

RESULTS

After screening a total of 463 studies, 11 eligible original articles were included in the review to analyze the effects of T1D on the auditory system. The included studies comprised cross-sectional and case-control investigations. A total of 5,792 patients were evaluated across the 11 articles included. The majority of the studies showed that T1D was associated with hearing impairment compared to controls, including differences in PTAs and OAEs, increased mean hearing thresholds, altered acoustic reflex thresholds, and problems with the medial olivocochlear (MOC) reflex inhibitory effect. Significant risk factors included older age, increased disease duration, and higher HbA1C levels.

CONCLUSIONS

This systematic review suggests that there is a correlation between T1D and impairment on the auditory system. A multidisciplinary collaboration between endocrinologists, otolaryngologists, and audiologists will lead to early detection of hearing impairment in people with T1D resulting in early intervention and better clinical outcomes in pursuit of improving the quality of life of affected individuals.

REGISTRATION

This systematic review is registered in PROSPERO (CRD42023438576).

Glucose control and outcomes in diabetic and nondiabetic patients treated with targeted temperature management after cardiac arrest

Hyperglycemia is commonly observed in critically ill patients and postcardiac arrest patients, with higher glucose levels and variability associated with poorer outcomes. In this study, we aim to compare glucose control in diabetic and nondiabetic patients using glycated hemoglobin (HbA1c) levels, providing insights for better glucose management strategies. This retrospective observational study was conducted at Seoul St. Mary's Hospital from February 2009 to May 2022. Blood glucose levels were measured hourly for 48 h after return of spontaneous circulation (ROSC), and a glucose management protocol was followed to maintain arterial blood glucose levels between 140 and 180 mg/dL using short-acting insulin infusion. Patients were categorized into four groups based on diabetes status and glycemic control. The primary outcomes assessed were neurological outcome and mortality at 6 months after cardiac arrest. Among the 332 included patients, 83 (25.0%) had a previous diabetes diagnosis, and 114 (34.3%) had an HbA1c of 6.0% or higher. At least one hyperglycemic episode was observed in 314 patients (94.6%) and hypoglycemia was found in 63 patients (19.0%) during 48 h. After the categorization, unrecognized diabetes was noticed in 51 patients with median HbA1c of 6.3% (interquartile range [IQR] 6.1-6.6). Patients with inadequate diabetes control had the highest initial HbA1c level (7.0%, IQR 6.5-7.8) and admission glucose (314 mg/dL, IQR 257-424). Median time to target glucose in controlled diabetes was significantly shorter with the slowest glucose reducing rate. The total insulin dose required to reach the target glucose level and cumulative insulin requirement during 48 h were different among the categories (p <0.001). Poor neurological outcomes and mortality were more frequently observed in patients with diagnosed diabetes. Occurrence of a hypoglycemic episode during the 48 h after ROSC was independently associated with poor neurologic outcomes (odds ratio [OR] 3.505; 95% confidence interval [CI], 2.382-9.663). Surviving patients following cardiac arrest exhibited variations in glucose hemodynamics and outcomes according to the categories based on their preexisting diabetes status and glycemic condition. Specifically, even experiencing a single episode of hypoglycemia during the acute phase could have an influence on unfavorable neurological outcomes. While the classification did not directly affect neurological outcomes, the present results indicate the need for a customized approach to glucose control based on these categories.

Hexokinase-linked glycolytic overload and unscheduled glycolysis in hyperglycemia-induced pathogenesis of insulin resistance, beta-cell glucotoxicity, and diabetic vascular complications

Hyperglycemia is a risk factor for the development of insulin resistance, beta-cell glucotoxicity, and vascular complications of diabetes. We propose the hypothesis, hexokinase-linked glycolytic overload and unscheduled glycolysis, in explanation. Hexokinases (HKs) catalyze the first step of glucose metabolism. Increased flux of glucose metabolism through glycolysis gated by HKs, when occurring without concomitant increased activity of glycolytic enzymes-unscheduled glycolysis-produces increased levels of glycolytic intermediates with overspill into effector pathways of cell dysfunction and pathogenesis. HK1 is saturated with glucose in euglycemia and, where it is the major HK, provides for basal glycolytic flux without glycolytic overload. HK2 has similar saturation characteristics, except that, in persistent hyperglycemia, it is stabilized to proteolysis by high intracellular glucose concentration, increasing HK activity and initiating glycolytic overload and unscheduled glycolysis. This drives the development of vascular complications of diabetes. Similar HK2-linked unscheduled glycolysis in skeletal muscle and adipose tissue in impaired fasting glucose drives the development of peripheral insulin resistance. Glucokinase (GCK or HK4)-linked glycolytic overload and unscheduled glycolysis occurs in persistent hyperglycemia in hepatocytes and beta-cells, contributing to hepatic insulin resistance and beta-cell glucotoxicity, leading to the development of type 2 diabetes. Downstream effector pathways of HK-linked unscheduled glycolysis are mitochondrial dysfunction and increased reactive oxygen species (ROS) formation; activation of hexosamine, protein kinase c, and dicarbonyl stress pathways; and increased Mlx/Mondo A signaling. Mitochondrial dysfunction and increased ROS was proposed as the initiator of metabolic dysfunction in hyperglycemia, but it is rather one of the multiple downstream effector pathways. Correction of HK2 dysregulation is proposed as a novel therapeutic target. Pharmacotherapy addressing it corrected insulin resistance in overweight and obese subjects in clinical trial. Overall, the damaging effects of hyperglycemia are a consequence of HK-gated increased flux of glucose metabolism without increased glycolytic enzyme activities to accommodate it.

Diabetes-induced male infertility: potential mechanisms and treatment options

Male infertility is a physiological phenomenon in which a man is unable to impregnate a fertile woman during a 12-month period of continuous, unprotected sexual intercourse. A growing body of clinical and epidemiological evidence indicates that the increasing incidence of male reproductive problems, especially infertility, shows a very similar trend to the incidence of diabetes within the same age range. In addition, a large number of previous in vivo and in vitro experiments have also suggested that the complex pathophysiological changes caused by diabetes may induce male infertility in multiple aspects, including hypothalamic-pituitary-gonadal axis dysfunction, spermatogenesis and maturation disorders, testicular interstitial cell damage erectile dysfunction. Based on the above related mechanisms, a large number of studies have focused on the potential therapeutic association between diabetes progression and infertility in patients with diabetes and infertility, providing important clues for the treatment of this population. In this paper, we summarized the research results of the effects of diabetes on male reproductive function in recent 5 years, elaborated the potential pathophysiological mechanisms of male infertility induced by diabetes, and reviewed and prospected the therapeutic measures.

Insulin resistance-related features are associated with cognitive decline: a cross-sectional study in adult patients with type 1 diabetes

BACKGROUND

To investigate the associations between insulin resistance (IR)-related features and cognitive function in type 1 diabetes (T1D).

METHODS

A total of 117 adult patients with T1D were recruited in this cross-sectional study. IR-related features include overweight/obesity/central obesity, hypertension, atherogenic dyslipidemia, and decreased estimated insulin sensitivity (eIS). The Wechsler Memory Scale-Chinese Revision, Wisconsin Card Sorting Test, and Sustained Attention to Response Task was used to assess memory, executive function and sustained attention, respectively. A z-score was generated from each test, and a composite measure of global cognitive performance was calculated by averaging the z-scores of all tests. Cognitive differences were measured between T1D patients with and without IR-related features. The associations between IR-related features and and cognitive performance were analyzed using: logistic regression, partial correlation, and multivariate linear regression analysis.

RESULTS

A total of 53 (45.3%) T1D patients were defined as having IR-related features. Individuals with IR-related features displayed worse overall cognitive scores compared to those without and had a 4-fold increase in the risk for having global cognitive z-score < 0. Among the IR-related features, higher triglyceride (TG) and lower eIS showed linear correlation with lower global cognitive performance. And the subsequent regression analysis identified eIS as the factor independently associated with global cognitive performance.

CONCLUSIONS

We have provided evidence linking IR-related features to deteriorated cognitive function in adult patients with T1D. And eIS showed an independent positive correlation with global cognitive performance. Although no causal relationship can be drawn, IR emerges as an important factor reflecting cognitive function.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03610984.

Association of thyroid function with non-alcoholic fatty liver disease in recent-onset diabetes

BACKGROUND AND AIMS

Non-alcoholic fatty liver disease (NAFLD) has been linked to type 2 diabetes (T2D), but also to hypothyroidism. Nevertheless, the relationship between thyroid function and NAFLD in diabetes is less clear. This study investigated associations between free thyroxine (fT4) or thyroid-stimulating hormone (TSH) and NAFLD in recent-onset diabetes.

METHODS

Participants with recent-onset type 1 diabetes (T1D, n = 358), T2D (n = 596) or without diabetes (CON, n = 175) of the German Diabetes Study (GDS), a prospective longitudinal cohort study, underwent Botnia clamp tests and assessment of fT4, TSH, fatty liver index (FLI) and in a representative subcohort 1 H-magnetic resonance spectroscopy.

RESULTS

First, fT4 levels were similar between T1D and T2D (p = .55), but higher than in CON (T1D: p < .01; T2D: p < .001), while TSH concentrations were not different between all groups. Next, fT4 correlated negatively with FLI and positively with insulin sensitivity only in T2D (ß = -.110, p < .01; ß = .126, p < .05), specifically in males (ß = -.117, p < .05; ß = .162; p < .01) upon adjustments for age, sex and BMI. However, correlations between fT4 and FLI lost statistical significance after adjustment for insulin sensitivity (T2D: ß = -.021, p = 0.67; males with T2D: ß = -.033; p = .56). TSH was associated positively with FLI only in male T2D before (ß = .116, p < .05), but not after adjustments for age and BMI (ß = .052; p = .30).

CONCLUSIONS

Steatosis risk correlates with lower thyroid function in T2D, which is mediated by insulin resistance and body mass, specifically in men, whereas no such relationship is present in T1D.

Early weight gain after diagnosis may have an impact on remission status in children with new-onset type 1 diabetes mellitus

BACKGROUND

Residual beta-cell function and improvement in insulin sensitivity by reversal of glucose toxicity are two phenomena thought to be related to partial remission (PR). Body fat mass is the major determinant of insulin sensitivity. The aim of this study is to investigate the relationship between the rate of body weight gain after diagnosis of type 1 diabetes mellitus (T1DM) and other clinical factors for the development and duration of PR.

METHODS

Children (2-16 years) with new-onset T1DM (n = 99) were grouped into remitters and non-remitters by using insulin dose-adjusted glycosylated hemoglobin (HbA1c) values. Laboratory and clinical data as well as daily insulin requirement per kilogram of body weight at diagnosis and each visit were recorded, and the duration of PR was determined. Changes in body mass index standard deviation score (BMI-SDS) were calculated by the auxological data collected every 6 months.

RESULTS

There were 47 remitters (47.5%) and 52 (52.5%) non-remitters. The mean increase in BMI-SDS at the first 6 months of diagnosis was higher in the non-remitters than in the remitters (p = 0.04). Duration of PR was negatively correlated with the change in BMI-SDS between 6 and 12 months after diagnosis. Male sex, younger age, prepubertal status, and lower HbA1c were predictors of remission, among which male sex had the highest chance by multivariate regression.

CONCLUSIONS

Early rapid weight gain after diagnosis of T1DM may play a role in the lack of remission and shorter duration of PR. Interventions to prevent early rapid weight gain can maintain the development and prolongation of remission.

Reduced Insulin Clearance Differently Relates to Increased Liver Lipid Content and Worse Glycemic Control in Recent-Onset Type 2 and Type 1 Diabetes

OBJECTIVE

Diabetes may feature impaired insulin kinetics, which could be aggravated by altered hepatic metabolism and glycemic control. Thus, we examined insulin clearance and its possible determinants in individuals with recent-onset diabetes.

RESEARCH DESIGN AND METHODS

Participants of the German Diabetes Study (GDS) with type 1 diabetes (T1D) (n = 306), type 2 diabetes (T2D) (n = 489), or normal glucose tolerance (control [CON]) (n = 167) underwent hyperinsulinemic-euglycemic clamps for assessment of whole-body insulin sensitivity (M value) and insulin clearance (ICCLAMP). Insulin clearance rates were further calculated during intravenous glucose tolerance tests (ICIVGTT) and mixed-meal tests (ICMMT). Hepatocellular lipid content (HCL) was quantified with 1H-MRS.

RESULTS

Both T1D and T2D groups had lower ICCLAMP (0.12 ± 0.07 and 0.21 ± 0.06 vs. 0.28 ± 0.14 arbitrary units [a.u.], respectively, all P < 0.05) and ICMMT (0.71 ± 0.35 and 0.99 ± 0.33 vs. 1.20 ± 0.36 a.u., all P < 0.05) than CON. In T1D, ICCLAMP, ICIVGTT, and ICMMT correlated negatively with HbA1c (all P < 0.05). M value correlated positively with ICIVGTT in CON and T2D (r = 0.199 and r = 0.178, P < 0.05) and with ICMMT in CON (r = 0.176, P < 0.05). HCL negatively associated with ICIVGTT and ICMMT in T2D (r = -0.005 and r = -0.037) and CON (r = -0.127 and r = -0.058, all P < 0.05). In line, T2D or CON subjects with steatosis featured lower ICMMT than those without steatosis (both P < 0.05).

CONCLUSIONS

Insulin clearance is reduced in both T1D and T2D within the first year after diagnosis but correlates negatively with liver lipid content rather in T2D. Moreover, insulin clearance differently associates with glycemic control and insulin sensitivity in each diabetes type, which may suggest specific mechanisms affecting insulin kinetics.

Serum Mg Isotopic Composition Reveals That Mg Dyshomeostasis Remains in Type 1 Diabetes despite the Resolution of Hypomagnesemia

Hypomagnesemia was historically prevalent in individuals with type 1 diabetes mellitus (T1DM), but contemporary results indicate an incidence comparable to that in the general population, likely due to improved treatment in recent decades, resulting in better glycemic control. However, a recent study found a significant difference between the serum Mg isotopic composition of T1DM individuals and controls, indicating that disruptions to Mg homeostasis persist. Significant deviations were also found in samples taken one year apart. To investigate whether the temporal variability in serum Mg isotopic composition is linked to the transient impact of administered insulin, Mg isotope ratios were determined in serum from 15 T1DM individuals before and one hour after insulin injection/meal consumption using multi-collector inductively coupled plasma-mass spectrometry. Consistent with results of the previous study, significant difference in the serum Mg isotopic composition was found between T1DM individuals and 10 sex-matched controls. However, the average difference between pre- and post-insulin injection/meal T1DM samples of 0.05 ± 0.13‱ (1SD) was not significant. No difference was observed for controls before (-0.12 ± 0.16‱) and after the meal (-0.10 ± 0.13‱) either, suggesting a lack of a postprandial Mg isotopic response within one hour of food consumption, and that the timing of the most recent meal may not require controlling for when determining serum Mg isotopic composition.

Insulin Resistance in Adolescents and Youth With Type 1 Diabetes: A Review of Problems and Solutions

Though insulin resistance (IR) was previously considered a feature of only type 2 Diabetes (T2DM), its development in type 1 Diabetes (T1DM) is not an uncommon occurrence, the causes of which are multifactorial (gender, pubertal status, diabetes duration, ethnicity, genetics, adiposity, glycemic control, chronic inflammation). Despite improvements in glucose, blood pressure and lipid profile, vascular complications (coronary artery disease and nephropathy) continue to remain common causes of morbidity and mortality in T1DM. Aggressive glycemic control reduces but does not eliminate the risk of IR. IR accelerates the development of micro and macrovascular complications, many of which can be potentially reversed if diagnosed and managed early. Lack of endogenous insulin production makes estimation of insulin sensitivity in T1DM difficult. As hyperinsulinemic-euglycemic clamp studies are cumbersome and invasive, the use of prediction equations for calculating estimated insulin sensitivity may prove to be useful. Along with intensive insulin therapy, dietary modifications and increasing physical activity, the role of Metformin in managing IR in T1DM is becoming increasingly popular. Metformin adjunct therapy in T1DM has been shown to improve insulin sensitivity, glycemic control, lipid profile, body composition, vascular smooth muscle function, thereby reducing the risk of vascular complications, as well as reversal of early vascular dysfunction. However, further studies to assess long-term efficacy and safety of Metformin use in adolescents and youth with T1DM are needed. This review aims at revisiting the pathophysiology of IR in T1DM and techniques of identifying those at risk so as to put into action various strategies for management of the same.

Type 1 and Type 2 Diabetes Mellitus: Commonalities, Differences and the Importance of Exercise and Nutrition

Diabetes mellitus represents a group of physiological dysfunctions characterized by hyperglycaemia resulting directly from insulin resistance (in the case of type 2 diabetes mellitus-T2DM), inadequate insulin secretion/production, or excessive glucagon secretion (in type 1 diabetes mellitus-T1DM) [...].

IGF1 and PPARG polymorphisms are associated with reduced estimated glomerular filtration rate in a cohort of children and adolescents with type 1 diabetes

INTRODUCTION

Several genetic loci have been associated with diabetic nephropathy; however, the underlying genetic mechanisms are still poorly understood, with no robust candidate genes identified yet.

AIM

We aimed to determine whether two polymorphisms, previously associated with renal decline, influence kidney impairment evaluating their association with markers of renal function in a pediatric population with type 1 diabetes (T1D).

MATERIAL AND METHODS

Renal function was evaluated by glomerular filtration rate (eGFR) and albumin-to-creatinine ratio (ACR) in a cohort of pediatric subjects with T1D (n = 278). Risk factors for diabetes complications (diabetes duration, blood pressure, HbA1c) were assessed. The IGF1 rs35767 and PPARG rs1801282 SNPs were genotyped by TaqMan RT-PCR system. An additive genetic interaction was calculated. Association analysis between markers of renal function and both SNPs or their additive interaction were performed.

RESULTS

Both SNPs showed a significant association with eGFR: the A allele of rs35767 or the C allele of rs1801282 were associated to reduced eGFR compared to G alleles. Multivariate regression analysis adjusted for age, sex, z-BMI, T1D duration, blood pressure and Hba1c values showed that the additive genetic interaction was independently associated with lower eGFR (β = -3.59 [-6.52 to -0.66], p = 0.017). No associations were detected between SNPs, their additive interaction and ACR.

CONCLUSIONS

These results provide new insight into the genetic predisposition to renal dysfunction, showing that two polymorphisms in IGF1 and PPARG genes can lead to a reduction in renal filtration rate leading these patients to be exposed to a higher risk of early renal complications.

Periodontitis is associated with insulin resistance in adults living with diabetes mellitus in Uganda: a cross- sectional study

INTRODUCTION

Evidence suggests that majority of patients with diabetes mellitus in Uganda have poor glycaemic control as well as periodontal disease. This study set out to determine the association between periodontitis and insulin resistance in adult patients with diabetes mellitus in Uganda using the triglyceride glucose index.

METHODS

Two hundred and twenty-three adult study participants with confirmed diabetes mellitus were enrolled in a cross-sectional study. Oral examination was carried with the aid of a periodontal probe to determine the periodontal status and findings recorded using the WHO Oral Health Assessment Tool for Adults, 2013. We recorded clinical details for body mass index (BMI in kg/m2) and laboratory parameters including fasting blood sugar (mmol/L), glycated hemoglobin levels (HbA1c, %) and serum triglycerides (mmol/L) using a study questionnaire. Data were analyzed using R version 4.10. The glucose triglyceride index was used as a measure of insulin resistance. Logistic regression analysis carried out to determine the factors associated insulin resistance.

RESULTS

The majority of the study participants was female (70%) with an average age of 48.5 years (SD+/- 11.1). The mean body mass index was 29.6 kg/m2 (SD+/- 5.82). The mean serum triglyceride index was 9.48 (SD+/- 0.675). Eighty-six-point 1% of the participants had periodontal disease. Bivariate analysis revealed high odds for male sex (OR = 1.31, 95% C.I = 0.44-4.84, p = 0.65) and periodontitis (OR = 3.65, 95% C.I = 0.79-26.15, p = 0.13) but low odds for a high BMI (OR = 0.45. 95% C.I = 0.07-1.67, p = 0.30). Multivariate regression revealed a significant association between insulin resistance and periodontitis. (AOR = 3.52, 95% C.I = 1.19-1.83, p = 0.03).

CONCLUSION

Insulin resistance is highly prevalent in patients with diabetes mellitus in Uganda and is associated with periodontitis and low body weight.

Insulin resistance is more frequent in type 1 diabetes patients with long disease duration

AIMS

To investigate the clinical status of insulin resistance (IR) and its correlation with disease duration in patients with type 1 diabetes (T1D).

MATERIALS AND METHODS

Cross-sectional data from a T1D cohort were obtained (n = 923). IR-related metabolic disorders including hypertension, obesity, and dyslipidemia were used as outcome variables to explore the cut-off point for estimated glucose disposal rate (eGDR) by restricted cubic spline (RCS) curve. Regression models were used for multivariate analysis of the clinical factors associated with IR. The correlation between the status of IR and diabetes duration was depicted with the RCS curve.

RESULTS

IR-related metabolic disorders were observed in 39.4% of patients, with 9.1% meeting the criteria for metabolic syndrome. Specifically, patients with ≥10 years of T1D were more likely to have IR-related metabolic disorders (54.7% vs. 36.9%, p < 0.05). The presence of IR, defined as an eGDR ≤9.0 mg/kg/min, was observed in 42.2% of patients. Patients with IR had a longer diabetes duration (3.5 vs. 2.7, years, p = 0.003) and higher insulin dose (0.5 vs. 0.4, units per kg per day, p < 0.001). Moreover, the presence of IR showed a gradual increase during 10 years' disease duration and further analysis showed that diabetes duration ≥10 years was a key element behind the development of IR and IR-related metabolic disorders.

CONCLUSIONS

The status of IR is common in T1D patients, especially in those with ≥10 years of disease duration. Therapies targeting balancing glycaemic control and IR are needed to decrease the future risk of cardiovascular diseases in T1D.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov NCT03610984 (cohort study of patients with type 1 diabetes).

Comparison of insulin resistance indices in predicting albuminuria among patients with type 2 diabetes

PURPOSE

Diabetes is the leading cause of kidney disease. Up to 40% of the population with diabetes experience diabetic kidney disease (DKD). The correlation of DKD with insulin resistance (IR) indices has been shown in previous studies. In this study, the objective was to evaluate surrogate IR indices, including the Triglyceride-Glucose (TyG) index, Visceral Adiposity Index (VAI), Lipid Accumulation Product (LAP), and Homeostasis Model Assessment of Insulin Resistance (HOMA-IR) to find the most valuable index for the correlation between albuminuria and IR in the type 2 diabetes (T2D) population. Albuminuria is defined as urine albumin excretion of > 30 mg/day.

METHODS

In this cross-sectional study, 2934 participants were enrolled and evaluated for urinary albumin excretion, and albuminuria was detected in 526 of the entries. The logistic regression models and Receiver Operating Characteristic (ROC) curve analysis were performed to assess the relationship of TyG index, VAI, LAP, and HOMA-IR's with albuminuria in patients with T2D.

RESULTS

The TyG index had the highest association (OR 1.67) with the presence of albuminuria in patients with T2D, followed by HOMA-IR (OR 1.127), VAI (OR 1.028), and LAP (OR 1.004). These four indices remained independent after adjustment for multiple confounders. Based on the ROC curve, TyG revealed the best area under the curve (AUC) for revealing albuminuria with sufficient accuracy (AUC: 0.62) in comparison with other measured indices. The calculated TyG index cut-off point for the presence of albuminuria was 9.39.

CONCLUSION

Among the indices, TyG index had the most significant correlation with albuminuria in patients with T2D.

Mitochondrial alterations in fatty liver diseases

Fatty liver diseases can result from common metabolic diseases, as well as from xenobiotic exposure and excessive alcohol use, all of which have been shown to exert toxic effects on hepatic mitochondrial functionality and dynamics. Invasive or complex methodology limits large-scale investigations of mitochondria in human livers. Nevertheless, abnormal mitochondrial function, such as impaired fatty acid oxidation and oxidative phosphorylation, drives oxidative stress and has been identified as an important feature of human steatohepatitis. On the other hand, hepatic mitochondria can be flexible and adapt to the ambient metabolic condition to prevent triglyceride and lipotoxin accumulation in obesity. Experience from studies on xenobiotics has provided important insights into the regulation of hepatic mitochondria. Increasing awareness of the joint presence of metabolic disease-related (lipotoxic) and alcohol-related liver diseases further highlights the need to better understand their mutual interaction and potentiation in disease progression. Recent clinical studies have assessed the effects of diets or bariatric surgery on hepatic mitochondria, which are also evolving as an interesting therapeutic target in non-alcoholic fatty liver disease. This review summarises the current knowledge on hepatic mitochondria with a focus on fatty liver diseases linked to obesity, type 2 diabetes and xenobiotics.

Liraglutide Attenuates Hepatic Oxidative Stress, Inflammation, and Apoptosis in Streptozotocin-Induced Diabetic Mice by Modulating the Wnt/β-Catenin Signaling Pathway

Liraglutide has been extensively applied in the treatment of type 2 diabetes mellitus and also has hepatoprotective effects. However, the role of liraglutide treatment on liver injury in a mouse model of type 1 diabetes mellitus (T1DM) induced by streptozotocin (STZ) and its underlying mechanisms remain to be elucidated. In the present study, diabetes was initiated in experimental animals by single-dose intraperitoneal inoculation of STZ. Forty female C57BL/6J mice were equally assigned into five groups: diabetic group, insulin+diabetic group, liraglutide+diabetic group, insulin+liraglutide+diabetic group, and control group for eight weeks. Diabetic mice exhibited a significantly elevated blood glucose level and decreased body weight, and morphological changes of increased steatosis and apoptosis were observed in the liver compared with the control. Furthermore, a significant increase in the levels of malondialdehyde and inflammatory markers such as tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and interleukin 1β (IL-1β) and the proapoptotic proteins caspase-3 and Bax were observed in the livers of diabetic mice, together with marked increases in antioxidants superoxide dismutase (SOD) and glutathione peroxidase (GPX) as well as antiapoptotic protein Bcl-2, all of which were significantly mitigated by treatment with liraglutide, insulin, and their combinations. Interestingly, liraglutide monotherapy showed better efficacy in ameliorating liver injury in T1DM mice than insulin monotherapy, similar to the combined drug therapy. Furthermore, the expression of Wnt/β-catenin signaling pathway-associated molecules was upregulated in the liver of mice treated with liraglutide or insulin. The results of the present study suggested that liraglutide improves T1DM-induced liver injury and may have important implications for the treatment of nonalcoholic fatty liver disease (NAFLD) in patients with T1DM.

The crucial role and mechanism of insulin resistance in metabolic disease

Insulin resistance (IR) plays a crucial role in the development and progression of metabolism-related diseases such as diabetes, hypertension, tumors, and nonalcoholic fatty liver disease, and provides the basis for a common understanding of these chronic diseases. In this study, we provide a systematic review of the causes, mechanisms, and treatments of IR. The pathogenesis of IR depends on genetics, obesity, age, disease, and drug effects. Mechanistically, any factor leading to abnormalities in the insulin signaling pathway leads to the development of IR in the host, including insulin receptor abnormalities, disturbances in the internal environment (regarding inflammation, hypoxia, lipotoxicity, and immunity), metabolic function of the liver and organelles, and other abnormalities. The available therapeutic strategies for IR are mainly exercise and dietary habit improvement, and chemotherapy based on biguanides and glucagon-like peptide-1, and traditional Chinese medicine treatments (e.g., herbs and acupuncture) can also be helpful. Based on the current understanding of IR mechanisms, there are still some vacancies to follow up and consider, and there is also a need to define more precise biomarkers for different chronic diseases and lifestyle interventions, and to explore natural or synthetic drugs targeting IR treatment. This could enable the treatment of patients with multiple combined metabolic diseases, with the aim of treating the disease holistically to reduce healthcare expenditures and to improve the quality of life of patients to some extent.

The influence of exercise training versus intensive insulin therapy on insulin resistance development in type 1 diabetes

The etiology of insulin resistance (IR) in Type 1 Diabetes (T1D) is unclear; however, intramyocellular lipids (IMCL) are likely contributors. While exercise lessens IR and IMCL content; T1D patients elevate glycemia to offset exercise-induced hypoglycemic risk. The preferred treatment for T1D patients is tight glucose management through intensive insulin therapy (IIT); however, IIT is accompanied with a sedentary lifestyle. The purpose of this study was to examine IR development and IMCL in combined exercise (DARE; aerobic/resistance) and IIT-treated T1D animals. 76 rats were divided into control sedentary (C), diabetic sedentary (CD), diabetes sedentary intensive insulin therapy (DIT) and DARE groups. Following streptozotocin (STZ), glycemia was maintained at either 9-15 mM (CD, DARE) or 5-9 mM (DIT) using insulin. DARE alternated between running and weighted climbing for 12 weeks. Results demonstrate that DARE exhibited reduced onset of IR compared with C, DIT and CD, indicated by increased glucose infusion rate (hyperinsulinemic-euglycemic-clamp). A shift in lipid metabolism was evident whereby diacylglycerol was elevated in DIT compared to DARE, while triacylglycerol was elevated in DARE. These findings indicate enhanced IMCL metabolism and the sequestration of fat as neutral triacylglycerol leads to reduced IR in DARE. In contrast, IIT and sedentary behavior leads to diacylglycerol accumulation and IR.

Phenolipid JE improves metabolic profile and inhibits gluconeogenesis via modulating AKT-mediated insulin signaling in STZ-induced diabetic mice

Phenolipids are characteristic phytochemicals of Syzygium genus. However, the antidiabetic potential and underlying molecular mechanism of these components are not fully elucidated. Herein, we studied the anti-diabetic effects of jambone E (JE), a phenolipid from S. cumini, with in vitro and in vivo models. Data from current study showed that JE enhanced glucose consumption and uptake, promoted glycogen synthesis, and suppressed gluconeogenesis in insulin resistant (IR)-HepG2 cells and primary mouse hepatocytes. JE also attenuated streptozotocin-induced hyperglycemia and hyperlipidemia in type 1 diabetic (T1D) mice. Eleven metabolites (e.g. trimethylamine n-oxide, 4-pyridoxic acid, phosphatidylinositol 39:4, phenaceturic acid, and hippuric acid) were identified as potential serum biomarkers for JE's antidiabetic effects by an untargeted metabolomics approach. The further molecular mechanistic study revealed that JE up-regulated phosphorylation levels of protein kinase B (AKT), glycogen synthase kinase 3 beta, and forkhead box O1 (FoxO1), promoted nuclear exclusion of FoxO1 whilst decreased gene expression levels of peroxisome proliferator-activated receptor gamma coactivator-1 alpha, phosphoenolpyruvate carboxykinase and glucose 6-phosphatase in IR-HepG2 cells and T1D mice. Our data suggested that JE might be a potent activator for AKT-mediated insulin signaling pathway, which was confirmed by the usage of AKT inhibitor and AKT-target siRNA interference, as well as the cellular thermal shift assay. Findings from the current study shed light on the anti-diabetic effects of phenolipids in the Syzygium species, which supports the use of medicinal plants in the Syzygium genus for potential pharmaceutical applications.

Sclareol ameliorates liver injury by inhibiting nuclear factor-kappa B/NOD-like receptor protein 3-mediated inflammation and lipid metabolism disorder in diabetic mice

Objectives: Sclareol (SCL) is a natural diterpene with anti-inflammation and antioxidant properties. This study aimed to assess the hepatoprotective effects of SCL in diabetic mice. Methods: SCL (10 mg/kg) was administered intragastrically to C57BL/6 mice with streptozotocin-induced diabetes daily for 5 weeks to evaluate its beneficial effects in liver injury. Body and liver weight and blood glucose levels were measured. Liver histopathology, fibrosis, and lipid accumulation were evaluated using hematoxylin and eosin, Masson's trichrome, and Oil Red O staining, respectively. Serum hepatic enzyme and lipid levels were measured using an automatic biochemical analyzer. Hepatocellular apoptosis was measured using the terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assay. Oxidative stress markers and reactive oxygen species (ROS) were measured using appropriate assay kits. The effects of sclareol on inflammation and lipid metabolism was evaluated by enzyme-linked immunosorbent assay (ELISA), immunohistochemical analysis, and Western blot assays. Results: SCL significantly decreased serum liver enzymes and lipids levels, and alleviated adipogenesis and fibrosis. Moreover, the protein levels of acetyl-CoA carboxylase and sterol response element-binding protein 1 were downregulated, whereas the expression of carnitine palmitoyl transferase 1 was upregulated. SCL increased the antioxidant activity, and decreased ROS levels. SCL alleviated hepatic mitochondrial damage. Furthermore, SCL inhibited Kupffer cell infiltration and reduced serum inflammatory cytokine levels. SCL significantly downregulated the protein expression of nuclear factor-kappa B (NF-κB) P65, NOD-like receptor protein 3 (NLRP3), caspase 1, and interleukin-1β. Conclusions: Our findings suggest that SCL improves diabetes-induced liver injury by alleviating the NF-κB/NLRP3-mediated inflammation and lipid metabolism disorder.

Assessment of Insulin Therapy as a Risk Factor for Hirsutism Among Diabetic Females in Saudi Arabia

Introduction Hirsutism is defined as a condition in which women develop excessive body hair in androgen-dependent areas, which include lips, chin, chest, abdomen, back, and femoral region. The link between hyperandrogenism and insulin resistance and/or hyperinsulinemia is well established. Polycystic ovary syndrome, as a form of hyperandrogenism, has been linked to several diseases, including type 2 diabetes mellitus and hirsutism. However, it is unknown how common hyperandrogenic problems are in women who receive exogenous insulin. Therefore, this study aims to assess the effect of insulin intake and other sociodemographic factors on the development of hirsutism among diabetic females. Methods This case-control study was conducted in six regions of Saudi Arabia, including Al-Ahsa, Dammam, Qatif, Riyadh, Abha, and Jeddah, during the year 2022. The population was Saudi females who were diabetic, between the age of 18 and 65 years, and living in Saudi Arabia. The sample size was 186 participants. Of the participants, 48 had considerable hirsutism whereas 138 did not. The degree of hirsutism has been determined using the Ferriman and Gallwey scoring tool. Results A total of 186 diabetic females were included in the study. Among the females, 97 (52.2%) were on insulin therapy and 89 (47.8%) were on non-insulin therapies. Only hair distribution on the chin showed a significant difference between the study groups where 4.1% of cases on insulin showed complete cover with light or heavy hair on the chin compared to 3.4% of controls (P = 0.049). There was no significant difference regarding hirsutism score among the study patients according to insulin intake where the mean score was 5.4 ± 5.1 among cases on insulin versus 4.7 ± 5.1 for controls (P = 0.978). Adjusted logistic regression models showed an insignificant association between diabetic female hirsutism and insulin intake (OR = 1.1 and 1.0, respectively; P > 0.05). Conclusion Many factors were examined to reveal their associations with hirsutism in diabetic females. Neither the type of diabetes nor insulin intake was significantly correlated with the development of hirsutism. On the other hand, age was found to be significantly associated with the development of hirsutism among age groups (<30, 30-49, and 50+; P = 0.49). It seemed that the prevalence of hirsutism decreases as age advances.

The Effects of Exercise Training on Glucose Homeostasis and Muscle Metabolism in Type 1 Diabetic Female Mice

Although exercise training is an important recommendation for the management of type 1 diabetes (T1D), most of the available research studies predominantly focus on male subjects. Given the importance of sex as a biological variable, additional studies are required to improve the knowledge gap regarding sex differences in T1D research. Therefore, the purpose of this study was to examine the role of exercise training in mediating changes in glucose homeostasis and skeletal muscle metabolism in T1D female mice. Female mice were injected with streptozotocin (STZ) to induce T1D. Two weeks after STZ injection, control (CON) and STZ mice were exercise trained on a treadmill for 4 weeks. Aerobic exercise training failed to improve glucose tolerance, prevent the decrease in body weight and adipose tissue mass, or attenuate muscle atrophy in T1D female mice. However, insulin sensitivity was improved in T1D female mice after exercise training. Aerobic exercise training maintained skeletal muscle triglyceride content but did not prevent depletion of skeletal muscle or liver glycogen in T1D mice. Gene expression analysis suggested that T1D resulted in decreased glucose transport, decreased ketone body oxidation, and increased fatty acid metabolism in the skeletal muscle, which was not altered by exercise training. These data demonstrate that 4 weeks of aerobic exercise training of a moderate intensity is insufficient to counteract the negative effects of T1D in female mice, but does lead to an improvement in insulin sensitivity.

Metabolic Factors Predict Changes in Endothelial Function During the Early Course of Type 1 and Type 2 Diabetes

CONTEXT

Endothelial dysfunction may occur early in the development of cardiovascular and metabolic diseases; however, it remains often underestimated and studies rarely discriminate between diabetes types. We have examined endothelial function and its determinants during the early course of type 1 and type 2 diabetes.

METHODS

Caucasian participants of the prospective German Diabetes Study (GDS) with known diabetes duration <1 year (n = 398) or without diabetes, but of similar age, body mass index (BMI) and sex distribution (n = 109), underwent measurements of flow-mediated dilation (FMD) and nitroglycerin-mediated dilatation (NMD). Whole-body insulin sensitivity (M-value) was assessed by hyperinsulinemic-euglycemic clamps and physical fitness (VO2max) by spiroergometry. A subset of individuals with type 1 or type 2 diabetes (n = 108) was re-evaluated after 5 years.

RESULTS

At baseline, neither FMD nor NMD differed between people with diabetes and the matched glucose-tolerant groups. At the 5-year follow-up, decline in FMD (-13.9%, P = .013) of persons with type 2 diabetes was independent of age, sex, and BMI, but associated with baseline adipose tissue insulin resistance and indices of liver fibrosis. The M-value decreased in both type 1 and type 2 diabetes groups by 24% and 15% (both P < .001, respectively) over 5 years. Higher HbA1c, lower M-value, and lower VO2max at baseline was associated with lower FMD in both type 1 and type 2 diabetes.

CONCLUSION

Endothelial function decreases during the early course of type 2 diabetes. In addition to age and BMI, insulin sensitivity at diagnosis was the best predictor of progressive impairment in endothelial function in type 2 diabetes.

Highlighting the Role of Obesity and Insulin Resistance in Type 1 Diabetes and Its Associated Cardiometabolic Complications

PURPOSE OF REVIEW

This narrative review appraises research data on the potentially harmful effect of obesity and insulin resistance (IR) co-existence with type 1 diabetes mellitus (T1DM)-related cardiovascular (CVD) complications and evaluates possible therapeutic options.

RECENT FINDINGS

Obesity and IR have increasingly been emerging in patients with T1DM. Genetic, epigenetic factors, and subcutaneous insulin administration are implicated in the pathogenesis of this coexistence. Accumulating evidence implies that the concomitant presence of obesity and IR is an independent predictor of worse CVD outcomes. The prevalence of obesity and IR has increased in patients with T1DM. This increase can be partly attributed to general population trends but, additionally, to iatrogenic weight gain caused by insulin treatment. This association might be the missing link explaining the excess CVD burden observed in patients with T1DM despite optimal glycemic control. Data on newer agents for type 2 diabetes mellitus (T2DM) treatment are unraveling novel ways to challenge this aggravating coexistence.

The role of pancreas to improve hyperglycemia in STZ-induced diabetic rats by thiamine disulfide

Background

The present study investigated the effect of thiamine disulfide (TD) on the pancreas in terms of hyperglycemia improvement and insulin sensitivity increase in diabetic male rats. We also aimed to study the function of Pdx1 (pancreatic and duodenal homeobox 1) and Glut2 (glucose transporter 2) genes in pancreatic tissue.

Methods

Type 1 diabetes was induced through injection of 60 mg/kg streptozotocin (STZ). The diabetic rats were divided into four groups, namely diabetic control (DC), diabetic treated with thiamine disulfide (D-TD), diabetic treated with insulin (D-insulin), and diabetic treated with TD and insulin (D-insulin+TD). The non-diabetic (NDC) and diabetic groups received a normal diet (14 weeks). Blood glucose level and body weight were measured weekly; insulin tolerance test (ITT) and glucagon tolerance test (GTT) were performed in the last month of the study. The level of serum insulin and glucagon were measured monthly and a hyperglycemic clamp (Insulin Infusion rate (IIR)) was done for all the groups. Pancreas tissue was isolated so that Pdx1and Glut2 genes expression could be measured.

Results

We observed that TD therapy decreased blood glucose level, ITT, and serum glucagon levels in comparison with those of the DC group; it also increased serum insulin levels, IIR, and expression of Pdx1 and Glut2 genes in comparison with those of the DC group.

Conclusion

Administration of TD could improve hyperglycemia in type 1 diabetic animals through improved pancreas function. Therefore, not only does TD have a significant effect on controlling and reducing hyperglycemia in diabetes, but it also has the potential to decrease the dose of insulin administration.

Can gallic acid potentiate the antihyperglycemic effect of acarbose and metformin? Evidence from streptozotocin-induced diabetic rat model

This study investigated the influence of dietary phenolic acid- Gallic acid (GA) on the antihyperglycemic properties of acarbose (ACA) and metformin (MET). Streptozotocin-induced diabetic rats were treated (p.o) with ACA, MET, GA and their combinations for 14 days. The effects of the treatments on blood glucose and insulin levels, pancreas α-amylase and intestinal α-glucosidase activities, as well as thiobarbituric acid reactive species (TBARS), thiol and reactive oxygen species (ROS) levels, including antioxidant enzyme activities were investigated. A significant increase in blood glucose, insulin, ROS and TBARS levels, and impaired antioxidant status, as well as elevation in the activities of α-amylase and α-glucosidase observed in diabetic rats were ameliorated in the treatment groups. Hpwever, GA had varying effects on the antidiabetic properties of the drugs. Nevertheless, GA showed more potentiating effects on the antidiabetic effect of MET and these effects were better observed at the lower dose of GA.

Space Flight-Promoted Insulin Resistance as a Possible Disruptor of Wound Healing

During space flight, especially when prolonged, exposure to microgravity results in a number of pathophysiological changes such as bone loss, muscle atrophy, cardiovascular and metabolic changes and impaired wound healing, among others. Interestingly, chronic low-grade inflammation and insulin resistance appear to be pivotal events linking many of them. Interestingly, real and experimental microgravity is also associated to altered wound repair, a process that is becoming increasingly important in view of prolonged space flights. The association of insulin resistance and wound healing impairment may be hypothesized from some dysmetabolic conditions, like the metabolic syndrome, type 2 diabetes mellitus and abdominal/visceral obesity, where derangement of glucose and lipid metabolism, greater low-grade inflammation, altered adipokine secretion and adipocyte dysfunction converge to produce systemic effects that also negatively involve wound healing. Indeed, wound healing impairment after traumatic events and surgery in space remains a relevant concern for space agencies. Further studies are required to clarify the molecular connection between insulin resistance and wound healing during space flight, addressing the ability of physical, endocrine/metabolic, and pharmacological countermeasures, as well as nutritional strategies to prevent long-term detrimental effects on tissue repair linked to insulin resistance. Based on these considerations, this paper discusses the pathophysiological links between microgravity-associated insulin resistance and impaired wound healing.

The role of mitochondria in the pathophysiology and treatment of common metabolic diseases in humans

Common metabolic diseases such as obesity, type 2 diabetes mellitus and non-alcoholic fatty liver disease significantly contribute to morbidity and mortality worldwide. They frequently associate with insulin resistance and altered mitochondrial functionality. Insulin-responsive tissues can show changes in mitochondrial features such as oxidative capacity, mitochondrial content and turnover, which do not necessarily reflect abnormalities but rather adaption to a certain metabolic condition. Lifestyle modifications and classic or novel drugs can modify these alterations and help treating these metabolic diseases. This review addresses the role of mitochondria in human metabolic diseases and discusses potential future research directions.

Muscular carnosine is a marker for cardiorespiratory fitness and cardiometabolic risk factors in men with type 1 diabetes

PURPOSE

Muscle is an essential organ for glucose metabolism and can be influenced by metabolic disorders and physical activity. Elevated muscle carnosine levels have been associated with insulin resistance and cardiometabolic risk factors. Little is known about muscle carnosine in type 1 diabetes (T1D) and how it is influenced by physical activity. The aim of this study was to characterize muscle carnosine in vivo by proton magnetic resonance spectroscopy (¹H MRS) and evaluate the relationship with physical activity, clinical characteristics and lipoprotein subfractions.

METHODS

16 men with T1D (10 athletes/6 sedentary) and 14 controls without diabetes (9/5) were included. Body composition by DXA, cardiorespiratory capacity (VO₂peak) and serum lipoprotein profile by proton nuclear magnetic resonance (¹H NMR) were obtained. Muscle carnosine scaled to water (carnosine_W) and to creatine (carnosine_CR), creatine and intramyocellular lipids (IMCL) were quantified in vivo using ¹H MRS in a 3T MR scanner in soleus muscle.

RESULTS

Subjects with T1D presented higher carnosine CR levels compared to controls. T1D patients with a lower VO₂peak presented higher carnosine_CR levels compared to sedentary controls, but both T1D and control groups presented similar levels of carnosine_CR at high VO₂peak levels. Carnosine_W followed the same trend. Integrated correlation networks in T1D demonstrated that carnosine_W and carnosine_CR were associated with cardiometabolic risk factors including total and abdominal fat, pro-atherogenic lipoproteins (very low-density lipoprotein subfractions), low VO₂peak, and IMCL.

CONCLUSIONS

Elevated muscle carnosine levels in persons with T1D and their effect on atherogenic lipoproteins can be modulated by physical activity.

Protective effects of physical activity against health risks associated with type 1 diabetes: "Health benefits outweigh the risks"

The magnitude of diabetes mellitus (DM) has increased in recent decades, where the number of cases and the proportion of the disease have been gradually increasing over the past few decades. The chronic complications of DM affect many organ systems and account for the majority of morbidity and mortality associated with the disease. The prevalence of type 1 DM (T1DM) is increasing globally, and it has a very significant burden on countries and at an individual level. T1DM is a chronic illness that requires ongoing medical care and patient self-management to prevent complications. This study aims to discuss the health benefits of physical activity (PA) in T1DM patients. The present review article was performed following a comprehensive literature search. The search was conducted using the following electronic databases: "Cochrane Library", Web of Science, PubMed, HINARI, EMBASE, Google for grey literature, Scopus, African journals Online, and Google Scholar for articles published up to June 21, 2021. The present review focused on the effects of PA on many outcomes such as blood glucose (BG) control, physical fitness, endothelial function, insulin sensitivity, well-being, the body defense system, blood lipid profile, insulin resistance, cardiovascular diseases (CVDs), insulin requirements, blood pressure (BP), and mortality. It was found that many studies recommended the use of PA for the effective management of T1DM. PA is a component of comprehensive lifestyle modifications, which is a significant approach for the management of T1DM. It provides several health benefits, such as improving BG control, physical fitness, endothelial function, insulin sensitivity, well-being, and the body defense system. Besides this, it reduces the blood lipid profile, insulin resistance, CVDs, insulin requirements, BP, and mortality. Overall, PA has significant and essential protective effects against the health risks associated with T1DM. Even though PA has several health benefits for patients with T1DM, these patients are not well engaged in PA due to barriers such as a fear of exercise-induced hypoglycemia in particular. However, several effective strategies have been identified to control exercise-induced hypoglycemia in these patients. Finally, the present review concludes that PA should be recommended for the management of patients with T1DM due to its significant health benefits and protective effects against associated health risks. It also provides suggestions for the future direction of research in this field.

Hexokinase-2-Linked Glycolytic Overload and Unscheduled Glycolysis-Driver of Insulin Resistance and Development of Vascular Complications of Diabetes

The recent discovery of the glucose-induced stabilization of hexokinase-2 (HK2) to proteolysis in cell dysfunction in model hyperglycemia has revealed a likely key initiating factor contributing to the development of insulin resistance and vascular complications in diabetes. Consequently, the increased flux of glucose metabolism without a change in the expression and activity of glycolytic enzymes produces a wave of increased glycolytic intermediates driving mitochondrial dysfunction and increased reactive oxygen species (ROS) formation, the activation of hexosamine and protein kinase C pathways, the increased formation of methylglyoxal-producing dicarbonyl stress, and the activation of the unfolded protein response. This is called HK2-linked glycolytic overload and unscheduled glycolysis. The conditions required to sustain this are GLUT1 and/or GLUT3 glucose uptake and the expression of HK2. A metabolic biomarker of its occurrence is the abnormally increased deposition of glycogen, which is produced by metabolic channeling when HK2 becomes detached from mitochondria. These conditions and metabolic consequences are found in the vasculature, kidneys, retina, peripheral nerves, and early-stage embryo development in diabetes and likely sustain the development of diabetic vascular complications and embryopathy. In insulin resistance, HK2-linked unscheduled glycolysis may also be established in skeletal muscle and adipose tissue. This may explain the increased glucose disposal by skeletal uptake in the fasting phase in patients with type 2 diabetes mellitus, compared to healthy controls, and the presence of insulin resistance in patients with type 1 diabetes mellitus. Importantly, glyoxalase 1 inducer—trans-resveratrol and hesperetin in combination (tRES-HESP)—corrected HK2-linked glycolytic overload and unscheduled glycolysis and reversed insulin resistance and improved vascular inflammation in overweight and obese subjects in clinical trial. Further studies are now required to evaluate tRES-HESP for the prevention and reversal of early-stage type 2 diabetes and for the treatment of the vascular complications of diabetes.

Basal insulin requirement in patients with type 1 diabetes depends on the age and body mass index

AIMS/INTRODUCTION

To investigate the basal insulin requirement in patients with type 1 diabetes who are on multiple daily injections (MDI) and to assess the patient characteristics that affect the percent of total daily basal insulin dose to the total daily insulin dose (%TBD/TDD).

MATERIALS AND METHODS

The subjects of this study were 67 inpatients with type 1 diabetes who were served diabetic meals of 25-30 kcal/kg standard body weight during several weeks of hospitalization. The basal insulin requirement was adjusted to keep the blood glucose level from bedtime to before breakfast within a 30 mg/dL difference. The bolus insulin dose before the meal was adjusted to keep the blood glucose level below 140 and 200 mg/dL before and 2 h after each meal, respectively. The total daily insulin dose (TDD), the percent of total daily basal insulin dose (TBD) to TDD (%TBD/TDD), and clinical characteristics were collected.

RESULTS

The median (Q1, Q3) of TDD was 33.0 (26.0, 49.0) units, and the %TBD/TDD was 24.1 ± 9.8%. The %TBD/TDD was positively correlated with the body mass index (BMI) and negatively correlated with the age at the onset and at the examination according to a univariate analysis. However, the %TBD/TDD was dependent on the BMI (β = 0.340, P = 0.004) and the age at examination (β = -0.288, P = 0.012) according to the multiple regression analysis.

CONCLUSIONS

The average %TBD/TDD in patients with type 1 diabetes on MDI was approximately 24% under inpatient conditions. The basal insulin requirement was dependent on the BMI and the age at examination.

Estimated insulin sensitivity, cardiovascular risk, and hepatic steatosis after 12 years from the onset of T1D

AIM

To test the hypothesis that intensive insulin treatment and optimal glycaemic control are not fully protective against reduction of insulin sensitivity in children with type 1 diabetes.

MATERIAL AND METHODS

Cohort study of 78 normal-weight patients with prepubertal onset (T₀ ) and follow-up waves at 1 (T₁ ), 5 (T₅ ), 10 (T₁₀ ), and 12 (T₁₂ ) years; matched for age and sex to 30 controls at T₁₂ . Estimated insulin sensitivity (eIS) by three formulae; ultrasound evaluation of para and perirenal fat thickness; hepatic steatosis (HS); carotid intima media thickness (cIMT) at T₁₂ .

RESULTS

At T12, the 36 patients (46%) who had constantly or prevalently haemoglobin A1c (HbA1c) < 58 mmol/l during follow-up showed better eIS indexes (p = 0.049 to <0.0001); lipid profile (p = 0.042 to <0.0001), reduced fat mass (p = 0.012) and required lower insulin dose (p = 0.032) than the 42 patients (54%) with HbA1c ≥ 58 at T12. Patients (N = 25) with eIS_EDC  < 8.77 mg kg^-1  min^-1 showed higher cIMT (p < 0.0001). HS was found in 6 patients (∼8%). In patients and normal-weight controls, fat mass (p = 0.03), age (p = 0.03), cIMT (p = 0.05) predicted HS; eIS indexes (p from 0.04 to <0.0001) predicted cIMT. Body mass index, perirenal fat, fat mass, and triglycerides to high density lipoprotein cholesterol ratio were associated with eIS indexes (p from 0.03 to <0.0001).

CONCLUSIONS

Young T1D patients have reduced insulin sensitivity and higher cIMT. Adiposity, glucose, and lipid control over follow-up are likely to influence both. Enhanced adiposity seems of paramount relevance for the onset of HS in T1D patients alike in healthy youths.

Autoimmune Inflammation and Insulin Resistance: Hallmarks So Far and Yet So Close to Explain Diabetes Endotypes

PURPOSE OF REVIEW

Diabetes mellitus can be categorized into two major variants, type 1 and type 2. A number of traits such as clinical phenotype, age at disease onset, genetic background, and underlying pathogenesis distinguish the two forms.

RECENT FINDINGS

Recent evidence indicates that type 1 diabetes can be accompanied by insulin resistance and type 2 diabetes exhibits self-reactivity. These two previously unknown conditions can influence the progression and outcome of the disease. Unlike most conventional considerations, diabetes appears to consist of a spectrum of intermediate phenotypes that includes monogenic and polygenic loci linked to inflammatory processes including autoimmunity, beta cell impairment, and insulin resistance. Here we discuss why a shift of the classical bi-modal view of diabetes (autoimmune vs. non-autoimmune) is necessary in favor of a model of an immunological continuum of endotypes lying between the two extreme "insulin-resistant" and "autoimmune beta cell targeting," shaped by environmental and genetic factors which contribute to determine specific immune-conditioned outcomes.

Metal-organic frameworks (MOFs) as host materials for the enhanced delivery of biomacromolecular therapeutics

Biomacromolecular drugs have become an important class of therapeutic agents for the treatment of human diseases. Considering their high propensity for being degraded in the human body, the choice of an appropriate delivery system is key to ensure the therapeutic efficacy of biomacromolecular drugs in vivo. As an emerging class of supramolecular "host" materials, metal-organic frameworks (MOFs) exhibit advantages in terms of the tunability of pore size, encapsulation efficiency, controllable drug release, simplicity in surface functionalization and good biocompatibility. As a result, MOF-based host-guest systems have been extensively developed as a new class of flexible and powerful platform for the delivery of therapeutic biomacromolecules. In this review, we summarize current research progress in the synthesis of MOFs as delivery materials for a variety of biomacromolecules. Firstly, we briefly introduce the advances made in the use of biomacromolecular drugs for disease therapy and the types of commonly used clinical delivery systems. We then describe the advantages of using MOFs as delivery materials. Secondly, the strategies for the construction of MOF-encapsulated biomacromolecules (Biomacromolecules@MOFs) and the release mechanisms of the therapeutics are categorized. Thirdly, the application of MOFs to deliver different types of biomacromolecules (e.g., antigens/antibodies, enzymes, therapeutic proteins, DNA/RNA, polypeptides, and polysaccharides) for the treatment of various human diseases based on immunotherapy, gene therapy, starvation therapy and oxidation therapy is summarized. Finally, the remaining challenges and available opportunities for MOFs as drug delivery systems are outlined, which we anticipate will encourage additional research efforts directed towards developing Biomacromolecules@MOFs systems for biomedical applications.

Association between ICS use and risk of hyperglycemia in COPD patients: systematic review and meta-analysis

BACKGROUND

The effect of inhaled corticosteroids (ICS) on risk of hyperglycemia in patients with chronic obstructive pulmonary disease (COPD) remains ambiguous. The aim of this study is to evaluate the association between ICS use and the incidence of hyperglycemia related adverse effects in COPD patients.

METHODS

Medline/PubMed, Embase, the Cochrane Central Register of Controlled Trials (CENTRAL), and ClinicalTrials.gov were searched from inception to 25 May 2020. Randomized controlled trials (RCTs) of ICS versus control (non-ICS) treatment for COPD patients reporting on risk of hyperglycemia were included. The Mantel-Haenszel method with fixed-effects modeling was used to calculate pooled relative risks (RRs) and 95% confidence intervals (CIs).

RESULTS

Seventeen RCTs with 43,430 subjects were included in the meta-analysis. Pooled results suggested that there was no statistically significant difference in the risk of hyperglycemia between the ICS group and the control group (RR 1.02, 95% CI 0.90-1.16, P = 0.76). In addition, no significant difference was noted in the effect on glucose level (RR 1.20, 95% CI 0.79-1.82, P = 0.40), risk of diabetes progression (RR 0.84, 95% CI 0.20-3.51, P = 0.81) and new onset diabetes mellitus (RR 1.0, 95% CI 0.88-1.15, P = 0.95) between the ICS group and the control group. These findings also were consistent across all subgroup analyses.

CONCLUSIONS

Use of ICS does not have an effect on the blood glucose and is not associated with the risk of new onset diabetes mellitus and diabetes progression in patients with COPD. Further RCTs exploring the association between ICS use and risk of hyperglycemia in COPD patients are still needed to verify our results of this analysis.

The effects of exercise training versus intensive insulin treatment on skeletal muscle fibre content in type 1 diabetes mellitus rodents

BACKGROUND

Intensive-insulin treatment (IIT) strategy for patients with type 1 diabetes mellitus (T1DM) has been associated with sedentary behaviour and the development of insulin resistance. Exercising patients with T1DM often utilize a conventional insulin treatment (CIT) strategy leading to increased insulin sensitivity through improved intramyocellular lipid (IMCL) content. It is unclear how these exercise-related metabolic adaptations in response to exercise training relate to individual fibre-type transitions, and whether these alterations are evident between different insulin strategies (CIT vs. IIT).

PURPOSE

This study examined glycogen and fat content in skeletal muscle fibres of diabetic rats following exercise-training.

METHODS

Male Sprague-Dawley rats were divided into four groups: Control-Sedentary, CIT- and IIT-treated diabetic sedentary, and CIT-exercised trained (aerobic/resistance; DARE). After 12 weeks, muscle-fibre lipids and glycogen were compared through immunohistochemical analysis.

RESULTS

The primary findings were that both IIT and DARE led to significant increases in type I fibres when compared to CIT, while DARE led to significantly increased lipid content in type I fibres compared to IIT.

CONCLUSIONS

These findings indicate that alterations in lipid content with insulin treatment and DARE are primarily evident in type I fibres, suggesting that muscle lipotoxicity in type 1 diabetes is muscle fibre-type dependant.

Insulin-mediated muscle microvascular perfusion and its phenotypic predictors in humans

Insulin increases muscle microvascular perfusion and enhances tissue insulin and nutrient delivery. Our aim was to determine phenotypic traits that foretell human muscle microvascular insulin responses. Hyperinsulinemic euglycemic clamps were performed in 97 adult humans who were lean and healthy, had class 1 obesity without comorbidities, or controlled type 1 diabetes without complications. Insulin-mediated whole-body glucose disposal rates (M-value) and insulin-induced changes in muscle microvascular blood volume (ΔMBV) were determined. Univariate and multivariate analyses were conducted to examine bivariate and multivariate relationships between outcomes, ΔMBV and M-value, and predictor variables, body mass index (BMI), total body weight (WT), percent body fat (BF), lean body mass, blood pressure, maximum consumption of oxygen (VO2max), plasma LDL (LDL-C) and HDL cholesterol, triglycerides (TG), and fasting insulin (INS) levels. Among all factors, only M-value (r = 0.23, p = 0.02) and VO2max (r = 0.20, p = 0.047) correlated with ΔMBV. Conversely, INS (r = - 0.48, p ≤ 0.0001), BF (r = - 0.54, p ≤ 0.001), VO2max (r = 0.5, p ≤ 0.001), BMI (r = - 0.40, p < 0.001), WT (r = - 0.33, p = 0.001), LDL-C (r = - 0.26, p = 0.009), TG (r = - 0.25, p = 0.012) correlated with M-value. While both ΔMBV (p = 0.045) and TG (p = 0.03) provided significant predictive information about M-value in the multivariate regression model, only M-value was uniquely predictive of ΔMBV (p = 0.045). Thus, both M-value and VO2max correlated with ΔMBV but only M-value provided unique predictive information about ΔMBV. This suggests that metabolic and microvascular insulin responses are important predictors of one another, but most metabolic insulin resistance predictors do not predict microvascular insulin responses.

Efficacy of Caffeic Acid on Diabetes and Its Complications in the Mouse

Diabetic dyslipidemia and hyperglycemia contribute to excessive reactive oxygen species (ROS) production, leading to deleterious complications, such as nephropathy, atherosclerosis and cardiac dysfunction, and target major organs in the body. The aim of this study was to investigate the effect of caffeic acid (CA) on mouse weight and survival, serum level of fasting blood glucose (FBG), serum lipid parameters and atherogenic indices, oxidative damage in blood, liver and kidney tissue, pathophysiological changes and their function markers in healthy and alloxan-induced type 1 diabetic mice. Diabetes was induced in mice with a single intravenous injection of alloxan (75 mg kg⁻¹). Two days later, CA (50 mg kg⁻¹) was given intraperitoneally for seven days in diabetic mice. Diabetes affected glucose level, lipid profile, hematological and biochemical parameters, induced DNA damage and apoptotic/necrotic death in whole blood cells, liver and kidney, leading to weight loss and a decreased lifespan. CA treatment of diabetic mice revealed a protective effect on the liver and kidney, hypoglycemic and hypolipidemic properties and high protection against atherogenic outcomes. The obtained results suggest that CA is a safe and potent agent against diabetes that acts as an effective antioxidant in reducing serum glucose, lipid profile and atherogenic indices, leading to increased lifespan in mice.

Type 1 Diabetes Mellitus in the SARS-CoV-2 Pandemic: Oxidative Stress as a Major Pathophysiological Mechanism Linked to Adverse Clinical Outcomes

Recent reports have demonstrated the association between type 1 diabetes mellitus (T1DM) and increased morbidity and mortality rates during coronavirus disease (COVID-19) infection, setting a priority of these patients for vaccination. Impaired innate and adaptive immunity observed in T1DM seem to play a major role. Severe, life-threatening COVID-19 disease is characterized by the excessive release of pro-inflammatory cytokines, known as a "cytokine storm". Patients with T1DM present elevated levels of cytokines including interleukin-1a (IL), IL-1β, IL-2, IL-6 and tumor necrosis factor alpha (TNF-α), suggesting the pre-existence of chronic inflammation, which, in turn, has been considered the major risk factor of adverse COVID-19 outcomes in many cohorts. Even more importantly, oxidative stress is a key player in COVID-19 pathogenesis and determines disease severity. It is well-known that extreme glucose excursions, the prominent feature of T1DM, are a potent mediator of oxidative stress through several pathways including the activation of protein kinase C (PKC) and the increased production of advanced glycation end products (AGEs). Additionally, chronic endothelial dysfunction and the hypercoagulant state observed in T1DM, in combination with the direct damage of endothelial cells by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), may result in endothelial and microcirculation impairment, which contribute to the pathogenesis of acute respiratory syndrome and multi-organ failure. The binding of SARS-CoV-2 to angiotensin converting enzyme 2 (ACE2) receptors in pancreatic b-cells permits the direct destruction of b-cells, which contributes to the development of new-onset diabetes and the induction of diabetic ketoacidosis (DKA) in patients with T1DM. Large clinical studies are required to clarify the exact pathways through which T1DM results in worse COVID-19 outcomes.

Early changes in hepatic energy metabolism and lipid content in recent-onset type 1 and 2 diabetes mellitus

BACKGROUND & AIMS

Non-alcoholic fatty liver disease (NAFLD) is associated with abnormal mitochondrial capacity. While oxidative capacity can be increased in steatosis, hepatic ATP decreases in long-standing diabetes. However, longitudinal studies on diabetes-related NAFLD and its relationship to hepatic energy metabolism are lacking.

METHODS

This prospective study comprised volunteers with type 1 (T1DM, n = 30) and type 2 (T2DM, n = 37) diabetes. At diagnosis and 5 years later, we used ¹H/³¹P magnetic resonance spectroscopy to measure hepatocellular lipid (HCL), γATP and inorganic phosphate (Pi) concentrations, and to assess adipose tissue volumes. Insulin sensitivity was assessed by hyperinsulinemic-euglycemic clamps.

RESULTS

At diagnosis, individuals with T2DM had higher HCL and adipose tissue volumes, but lower whole-body insulin sensitivity than those with T1DM, despite comparable glycemic control. NAFLD was present in 38% of individuals with T2DM and 7% with T1DM. After 5 years, visceral adipose tissue only increased in individuals with T2DM, while HCL almost doubled in this group (p <0.001), resulting in a 70% prevalence of NAFLD (independent of diabetes treatment). Changes in HCL correlated with adipose tissue volume and insulin resistance (r = 0.50 and r = 0.44, both p <0.05). Pi decreased by 17% and 10% in individuals with T2DM and T1DM (p <0.05), respectively. In T1DM, HCL did not change, whereas γATP decreased by 10% and correlated negatively with glycated hemoglobin (r = -0.56, p <0.05).

CONCLUSIONS

The rapid increase in HCL during the early course of T2DM likely results from enlarging adipose tissue volume and insulin resistance in response to impaired hepatic mitochondrial adaptation. The decrease of phosphorus metabolites in T1DM may be due to pharmacological insulin supply.

LAY SUMMARY

Previous studies suggested that the impaired function of mitochondria, the power plants of cells, can promote fatty liver and type 2 diabetes mellitus. This study now shows that during the first 5 years of type 2 diabetes the increase in body fat content rapidly leads to a doubling of liver fat content, whereas the energy metabolism of the patients' livers progressively declines. These data suggest that fat tissue mass and liver mitochondria have an important role in the development of fatty liver disease in humans with diabetes.

CLINICAL TRIAL NUMBER

NCT01055093.