Sex-specific differences in insulin resistance in type 1 diabetes: The CACTI cohort

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.

Association between the triglyceride-glucose index and in-hospital major adverse cardiovascular events in patients with acute coronary syndrome: results from the Improving Care for Cardiovascular Disease in China (CCC)-Acute Coronary Syndrome project

OBJECTIVE

Although the TyG index is a reliable predictor of insulin resistance (IR) and cardiovascular disease, its effectiveness in predicting major adverse cardiac events in hospitalized acute coronary syndrome (ACS) patients has not been validated in large-scale studies. In this study, we aimed to explore the association between the TyG index and the occurrence of MACEs during hospitalization.

METHODS

We recruited ACS patients from the CCC-ACS (Improving Cardiovascular Care in China-ACS) database and calculated the TyG index using the formula ln(fasting triglyceride [mg/dL] × fasting glucose [mg/dL]/2). These patients were classified into four groups based on quartiles of the TyG index. The primary endpoint was the occurrence of MACEs during hospitalization, encompassing all-cause mortality, cardiac arrest, myocardial infarction (MI), and stroke. We performed Cox proportional hazards regression analysis to clarify the correlation between the TyG index and the risk of in-hospital MACEs among patients diagnosed with ACS. Additionally, we explored this relationship across various subgroups.

RESULTS

A total of 101,113 patients were ultimately included, and 2759 in-hospital MACEs were recorded, with 1554 (49.1%) cases of all-cause mortality, 601 (21.8%) cases of cardiac arrest, 251 (9.1%) cases of MI, and 353 (12.8%) cases of stroke. After adjusting for confounders, patients in TyG index quartile groups 3 and 4 showed increased risks of in-hospital MACEs compared to those in quartile group 1 [HR = 1.253, 95% CI 1.121-1.400 and HR = 1.604, 95% CI 1.437-1.791, respectively; p value for trend < 0.001], especially in patients with STEMI or renal insufficiency. Moreover, we found interactions between the TyG index and age, sex, diabetes status, renal insufficiency status, and previous PCI (all p values for interactions < 0.05).

CONCLUSIONS

In patients with ACS, the TyG index was an independent predictor of in-hospital MACEs. Special vigilance should be exercised in females, elderly individuals, and patients with renal insufficiency.

Cardiovascular Risk Factors in Adolescents with Type 1 Diabetes: Prevalence and Gender Differences

Objective

Cardiovascular diseases (CVD) are the most important cause of morbidity and mortality in patients with type 1 diabetes (T1D). Children with T1D have a similar or higher prevalence of being overweight (OW) or obese (Ob) compared to healthy peers. The aim of this study was to determine the prevalence of CVD risk factors in children and adolescents with T1D and the impact of obesity and sex differences on these factors.

Methods

Data of patients aged 10-21 years and who had been using intensive insulin therapy with a diagnosis of T1D for at least three years were evaluated. Patients were divided into normal weight (NW), OW and Ob groups based on body mass index percentiles. Risk factors for CVD (obesity, dyslipidemia, hypertension) were compared between groups, and impact of gender was also analyzed.

Results

Data of 365 patients (200 girls, 54.8%), were evaluated. Prevalence of OW/Ob was 25.9% and was significantly higher in girls (30.6% vs 20.1%, p<0.001). Rate of hypertension was highest in OW/Ob girls followed by OW/Ob boys, and similar in NW girls and boys (p=0.003). Mean low density lipoprotein cholesterol (LDL-c) and triglyceride (TG) levels were highest in OW/Ob girls, followed by OW/Ob boys, NW girls and NW boys, respectively (p<0.001 and p<0.001, respectively). Mean high density lipoprotein-cholesterol (HDL-c) levels were similar among groups. Rates of high LDL-c and TG were similar between OW/Ob girls and boys and higher than NW girls, followed by NW boys (p<0.001 and p<0.001, respectively). The rate of low HDL-c was similar in OW/Ob girls and boys, and higher than NW girls, followed by NW boys (p<0.001). Overall, girls were 1.9 times more likely than boys to have two or more risk factors for CVD. Factors associated with risk for CVD in multiple logistic regression analyses were being a girl, followed by higher daily insulin dose, higher hemoglobin A1c, and longer duration of diabetes (r=0.856; p<0.001).

Conclusion

In spite of the increased prevalence for obesity in both sexes, the trend for CVD risk factors was greater in Ob girls, followed by Ob boys and NW girls. Girls with T1D are more likely to be OW/Ob and to have CVD risk than boys, highlighting the need for early intervention and additional studies to elucidate the causes.

The Effects of Resistance Exercise Training on Skeletal Muscle Metabolism and Insulin Resistance Development in Female Rodents with Type 1 Diabetes

The etiology of insulin resistance (IR) development in type 1 diabetes mellitus (T1DM) remains unclear; however, impaired skeletal muscle metabolism may play a role. While IR development has been established in male T1DM rodents, female rodents have yet to be examined in this context. Resistance exercise training (RT) has been shown to improve IR and is associated with a lower risk of hypoglycemia onset in T1DM compared to aerobic exercise. The purpose of this study was to investigate the effects of RT on IR development in female T1DM rodents. Forty Sprague Dawley eight-week-old female rats were divided into four groups: control sedentary (CS; n = 10), control trained (CT; n = 10), T1DM sedentary (DS; n = 10), and T1DM trained (DT; n = 10). Multiple low-dose streptozotocin injections were used to induce T1DM. Blood glucose levels were maintained in the 4-9 mmol/l range with intensive insulin therapy. CT and DT underwent weighted ladder climbing 5 days/week for six weeks. Intravenous glucose tolerance tests (IVGTT) were conducted on all animals following the six-week period. Results demonstrate that DS animals exhibited significantly increased weekly blood glucose measures compared to all groups including DT (p < 0.0001), despite similar insulin dosage levels. This was concomitant with a significant increase in insulin-adjusted area under the curve following IVGTT in DS (p < 0.05), indicative of a reduction in insulin sensitivity. Both DT and DS exhibited greater serum insulin concentrations compared to CT and CS (p < 0.05). DS animals also exhibited significantly greater glycogen content in white gastrocnemius muscle compared to CS and DT (p < 0.05), whereas DT and DS animals exhibited greater p-Akt: Akt ratio in the white vastus lateralis muscle and citrate synthase activity in the red vastus lateralis muscle compared to CS and CT (p < 0.05). These results indicate that female rodents with T1DM develop poor glycemic control and IR which can be attenuated with RT, possibly related to differences in intramyocellular glycogen content.

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.

Plasma levels of carboxylic acids are markers of early kidney dysfunction in young people with type 1 diabetes

BACKGROUND

We compared plasma metabolites of amino acid oxidation and the tricarboxylic acid (TCA) cycle in youth with and without type 1 diabetes mellitus (T1DM) and related the metabolites to glomerular filtration rate (GFR), renal plasma flow (RPF), and albuminuria. Metabolites associated with impaired kidney function may warrant future study as potential biomarkers or even future interventions to improve kidney bioenergetics.

METHODS

Metabolomic profiling of fasting plasma samples using a targeted panel of 644 metabolites and an untargeted panel of 19,777 metabolites was performed in 50 youth with T1DM ≤ 10 years and 20 controls. GFR and RPF were ascertained by iohexol and p-aminohippurate clearance, and albuminuria calculated as urine albumin to creatinine ratio. Sparse partial least squares discriminant analysis and moderated t tests were used to identify metabolites associated with GFR and RPF.

RESULTS

Adolescents with and without T1DM were similar in age (16.1 ± 3.0 vs. 16.1 ± 2.9 years) and BMI (23.4 ± 5.1 vs. 22.7 ± 3.7 kg/m2), but those with T1DM had higher GFR (189 ± 40 vs. 136 ± 22 ml/min) and RPF (820 ± 125 vs. 615 ± 65 ml/min). Metabolites of amino acid oxidation and the TCA cycle were significantly lower in adolescents with T1DM vs. controls, and the measured metabolites were able to discriminate diabetes status with an AUC of 0.82 (95% CI: 0.71, 0.93) and error rate of 0.21. Lower glycine (r:-0.33, q = 0.01), histidine (r:-0.45, q < 0.001), methionine (r: -0.29, q = 0.02), phenylalanine (r: -0.29, q = 0.01), serine (r: -0.42, q < 0.001), threonine (r: -0.28, q = 0.02), citrate (r: -0.35, q = 0.003), fumarate (r: -0.24, q = 0.04), and malate (r: -0.29, q = 0.02) correlated with higher GFR. Lower glycine (r: -0.28, q = 0.04), phenylalanine (r:-0.3, q = 0.03), fumarate (r: -0.29, q = 0.04), and malate (r: -0.5, q < 0.001) correlated with higher RPF. Lower histidine (r: -0.28, q = 0.02) was correlated with higher mean ACR.

CONCLUSIONS

In conclusion, adolescents with relatively short T1DM duration exhibited lower plasma levels of carboxylic acids that associated with hyperfiltration and hyperperfusion.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03618420 and NCT03584217 A higher resolution version of the Graphical abstract is available as Supplementary information.

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.

Cardiovascular Disease in Adults with Type 1 Diabetes: Looking Beyond Glycemic Control

PURPOSE OF REVIEW

Despite improvements in treatment, people with type 1 diabetes continue to have increased cardiovascular disease (CVD) risk. Glycemic control does not fully explain this excess CVD risk, so a greater understanding of other risk factors is needed.

RECENT FINDINGS

The authors review the relationship between glycemia and CVD risk in adults with type 1 diabetes and summarize evidence regarding other factors that may explain risk beyond glycemia. Insulin resistance, weight gain, sex differences, genetics, inflammation, emerging markers of risk, including lipid subclasses and epigenetic modifications, and future directions are discussed. As glycemic control improves, an increased focus on other CVD risk factors is warranted in type 1 diabetes. Novel markers and precision medicine approaches may improve CVD prediction, but a lack of type 1 diabetes-specific guidelines for lipids, blood pressure, and physical activity are likely impediments to optimal CVD prevention in this high-risk population.

Sex differences in cardiovascular risk factors of children and adolescents with type 1 diabetes mellitus: A role for diet?

BACKGROUND AND AIMS

Cardiovascular disease is the leading cause of morbidity and mortality in individuals with type 1 diabetes mellitus (T1DM). Cardiovascular risk is higher in women with diabetes than in men. With this study, we wanted to determine whether female children and adolescents with T1DM are more prone to cardiovascular risk factors (CVRFs) and an atherogenic diet than boys.

METHODS AND RESULTS

For this cross-sectional study, anthropometric, clinical, biochemical, and dietary intake data of 314 children with diabetes (3-18 years; 178 boys) were analysed according to age and sex. Linear and binary logistic regression was performed to test independent associations between sex, dietary intake, and CVRFs. Low-density lipoprotein -cholesterol (LDL-c), triglyceride (TG), fibre, monounsaturated fatty acid levels (all p < 0.01), and lipid (p = 0.022) intake were higher in the girls than in the boys. Multiple regression analysis showed that LDL was associated with sex, glycated haemoglobin (HbA1c), and lipid intake percentage (R (Kannel, 1979) [2] = 0.130; p = 0.0004) independent of age, pubertal stage, body mass index (BMI), duration of diabetes, energy, and fibre intake. Logistic regression analysis showed that high LDL-c levels were present more often in girls [odds ratio, OR; confidence interval, CI = 2.569 (1.178-5.604); p = 0.018] who had a higher dietary lipid intake percentage [OR (CI) = 1.089 (1.011-1.173); p = 0.025].

CONCLUSIONS

Girls with diabetes have higher LDL-c levels associated with higher dietary lipid intake. Our findings suggest that young people with diabetes, especially girls, may benefit from early dietary interventions to reduce their cardiovascular risk.

Sex and Gender Related Differences in Diabetic Kidney Disease

Diversity in sex and gender are important considerations in the pathogenesis, prognostication, research, and management of diabetic kidney disease (DKD). Sex and gender differences in the disease risk, disease-specific mechanisms, and outcomes in DKD may be attributed to biological differences between males and females at the cellular and tissue level, inconsistencies in the diagnostic and assessment tools used in chronic kidney disease and DKD, as well societal differences in the way men, women, and gender-diverse individuals self-manage and interact with health care systems. This review outlines key considerations related to the impact of sex on DKD, specifically elaborating on how they contribute to observed differences in disease epidemiology, pathogenesis, and treatment strategies. We also highlight the effect of gender on DKD progression and care.

Can Resistance Exercise Be a Tool for Healthy Aging in Post-Menopausal Women with Type 1 Diabetes?

Due to improvements in diabetes care, people with type 1 diabetes (T1D) are living longer. Studies show that post-menopausal T1D women have a substantially elevated cardiovascular risk compared to those without T1D. As T1D may also accelerate age-related bone and muscle loss, the risk of frailty may be considerable for T1D women. Exercise and physical activity may be optimal preventative therapies to maintain health and prevent complications in this population: They are associated with improvements in, or maintenance of, cardiovascular health, bone mineral density, and muscle mass in older adults. Resistance exercise, in particular, may provide important protection against age-related frailty, due to its specific effects on bone and muscle. Fear of hypoglycemia can be a barrier to exercise in those with T1D, and resistance exercise may cause less hypoglycemia than aerobic exercise. There are currently no exercise studies involving older, post-menopausal women with T1D. As such, it is unknown whether current guidelines for insulin adjustment/carbohydrate intake for activity are appropriate for this population. This review focuses on existing knowledge about exercise in older adults and considers potential future directions around resistance exercise as a therapeutic intervention for post-menopausal T1D women.

Cardiovascular disease in diabetes, beyond glucose

Despite the decades-old knowledge that diabetes mellitus is a major risk factor for cardiovascular disease, the reasons for this association are only partially understood. While this association is true for both type 1 and type 2 diabetes, different pathophysiological processes may be responsible. Lipids and other risk factors are indeed important, whereas the role of glucose is less clear. This lack of clarity stems from clinical trials that do not unambiguously show that intensive glycemic control reduces cardiovascular events. Animal models have provided mechanisms that link diabetes to increased atherosclerosis, and evidence consistent with the importance of factors beyond hyperglycemia has emerged. We review clinical, pathological, and animal studies exploring the pathogenesis of atherosclerosis in humans living with diabetes and in mouse models of diabetes. An increased effort to identify risk factors beyond glucose is now needed to prevent the increased cardiovascular disease risk associated with diabetes.

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.

Sex-related differences in diabetic kidney disease: A review on the mechanisms and potential therapeutic implications

Sexual dimorphism may play a key role in the pathogenesis of diabetic kidney disease (DKD) and explain differences observed in disease phenotypes, responses to interventions, and disease progression between men and women with diabetes. Therefore, omitting the consideration of sex as a biological factor may result in delayed diagnoses and suboptimal therapies. This review will summarize the effects of sexual dimorphism on putative metabolic and molecular mechanisms underlying DKD, and the potential implications of these differences on therapeutic interventions. To successfully implement precision medicine, we require a better understanding of sexual dimorphism in the pathophysiologic progression of DKD. Such insights can unveil sex-specific therapeutic targets that have the potential to maximize efficacy while minimizing adverse events.

Triglyceride-glucose index is associated with the risk of myocardial infarction: an 11-year prospective study in the Kailuan cohort

Background

The triglyceride–glucose (TyG) index, which is a simple surrogate marker of insulin resistance, has been suggested as a contributor of cardiovascular disease. However, evidence on the effect of long-term elevation of the TyG index exposure on myocardial infarction (MI) is limited. The current study aimed to evaluate the association of baseline and long-term elevation of the TyG index exposure with the risk of MI.

Methods

A total of 98,849 participants without MI at baseline (2006) were enrolled from the Kailuan study. The baseline TyG index was calculated as ln [fasting triglyceride (mg/dL) × fasting glucose (mg/dL)/2]. The long-term TyG index was characterized in two ways as follows. The updated mean TyG index was calculated as the mean of TyG index at all previous visits before MI occurred or the end of follow-up; alternatively, the TyG index was calculated as the number of visits with a high TyG index in 2006, 2008, and 2010, ranging from 0 (no exposure) to 3 (had high TyG index at all three study visits). Hazard ratio (HR) and 95% confidence interval (CI) was estimated using multivariable Cox proportion hazard models.

Results

During a median follow-up of 11.03 years, 1555 incident MI occurred. In the multivariable-adjusted model, the risk of MI increased with quartiles of the baseline and updated mean TyG index, the HR in quartile 4 versus quartile 1 was 2.08 (95% CI,1.77–2.45) and 1.58 (1.18–2.12), respectively. Individuals with a high TyG index at all three visits had a 2.04-fold higher risk (95% CI, 1.63–2.56) of MI compared with no exposure. Subgroup analyses showed that the associations were more pronounced in women than in men (P_interaction = 0.0411).

Conclusions

Elevated levels of the baseline and long-term TyG index are associated with an increased risk of MI. This finding indicates that the TyG index might be useful in identifying people at high risk of developing MI.

The Causes of Insulin Resistance in Type 1 Diabetes Mellitus: Is There a Place for Quaternary Prevention?

Diabetes mellitus was the first non-communicable disease that was recognized by the United Nations as a 21st-century pandemic problem. Recent scientific reports suggest that people with type 1 diabetes mellitus also develop insulin resistance, which is generally considered to be a distinctive feature of type 2 diabetes mellitus. The causes of insulin resistance in type 1 diabetes mellitus were explored, but there was a lack of publications that connected the risk factors of insulin resistance in type 1 diabetes mellitus with the proposition of repair mechanisms that are offered by quaternary prevention. Toward this end, the present review is an attempt to combine the previous reports on the causes of insulin resistance in type 1 diabetes mellitus and a brief review of quaternary prevention. The destructive effect of insulin resistance on many physiological processes that predisposes the individual to chronic diabetes complications creates an urgent need to introduce effective therapeutic methods for preventing the development and progression of this pathology.

Different physiological mechanisms underlie an adverse cardiovascular disease risk profile in men and women

CVD affect about one-third of the population and are the leading cause of mortality. The prevalence of CVD is closely linked to the prevalence of obesity because obesity is commonly associated with metabolic abnormalities that are important risk factors for CVD, including insulin resistance, pre-diabetes, and type-2 diabetes, atherosclerotic dyslipidaemia, endothelial dysfunction and hypertension. Women have a more beneficial traditional CVD risk profile (lower fasting plasma glucose, less atherogenic lipid profile) and a lower absolute risk for CVD than men. However, the relative risk for CVD associated with hyperglycaemia and dyslipidaemia is several-fold higher in women than in men. The reasons for the sex differences in CVD risk associated with metabolic abnormalities are unclear but could be related to differences in the mechanisms that cause hyperglycaemia and dyslipidaemia in men and women, which could influence the pathogenic processes involved in CVD. In the present paper, we review the influence of a person's sex on key aspects of metabolism involved in the cardiometabolic disease process, including insulin action on endogenous glucose production, tissue glucose disposal, and adipose tissue lipolysis, insulin secretion and insulin plasma clearance, postprandial glucose, fatty acid, and triglyceride kinetics, hepatic lipid metabolism and myocardial substrate use. We conclude that there are marked differences in many aspects of metabolism in men and women that are not all attributable to differences in the sex hormone milieu. The mechanisms responsible for these differences and the clinical implications of these observations are unclear and require further investigation.

Sexual dimorphism in human skeletal muscle mitochondrial bioenergetics in response to type 1 diabetes

Sexual dimorphism in mitochondrial respiratory function has been reported in young women and men without diabetes, which may have important implications for exercise. The purpose of this study was to determine if sexual dimorphism exists in skeletal muscle mitochondrial bioenergetics in people with type 1 diabetes (T1D). A resting muscle microbiopsy was obtained from women and men with T1D (n = 10/8, respectively) and without T1D (control; n = 8/7, respectively). High-resolution respirometry and spectrofluorometry were used to measure mitochondrial respiratory function, hydrogen peroxide (mH₂O₂) emission and calcium retention capacity (mCRC) in permeabilized myofiber bundles. The impact of T1D on mitochondrial bioenergetics between sexes was interrogated by comparing the change between women and men with T1D relative to the average values of their respective sex-matched controls (i.e., delta). These aforementioned analyses revealed that men with T1D have increased skeletal muscle mitochondrial complex I sensitivity but reduced complex II sensitivity and capacity in comparison to women with T1D. mH₂O₂ emission was lower in women compared with men with T1D at the level of complex I (succinate driven), whereas mCRC and mitochondrial protein content remained similar between sexes. In conclusion, women and men with T1D exhibit differential responses in skeletal muscle mitochondrial bioenergetics. Although larger cohort studies are certainly required, these early findings nonetheless highlight the importance of considering sex as a variable in the care and treatment of people with T1D (e.g., benefits of different exercise prescriptions).

Type 1 Diabetes Accelerates Progression of Coronary Artery Calcium Over the Menopausal Transition: The CACTI Study

OBJECTIVE

Type 1 diabetes is associated with a higher risk of cardiovascular disease (CVD) in women. Although menopause increases risk of CVD, it is uncertain how menopause affects risk of CVD in women with type 1 diabetes. We examined whether risk of CVD changes differentially in women with and those without type 1 diabetes over the transition through menopause.

RESEARCH DESIGN AND METHODS

Premenopausal women with type 1 diabetes (n = 311) and premenopausal women without diabetes (n = 325) enrolled in the Coronary Artery Calcification in Type 1 Diabetes (CACTI) study and attended up to four study visits over 18 years. Coronary artery calcium (CAC) volume was measured from computed tomography scans obtained at each visit. Longitudinal repeated-measures modeling estimated the effect of diabetes on CAC volume over time and the effect of menopause on the diabetes-CAC relationship.

RESULTS

CAC volume was higher at baseline and increased more over time in women with type 1 diabetes than in women without diabetes. A significant diabetes-by-menopause interaction was found (P < 0.0001): postmenopausal women with type 1 diabetes had significantly higher CAC volumes than premenopausal women (5.14 ± 0.30 vs. 2.91 ± 0.18 mm³), while there was no difference in women without diabetes (1.78 ± 0.26 vs. 1.78 ± 0.17 mm³). This interaction remained significant after adjusting for CVD risk factors.

CONCLUSIONS

Type 1 diabetes was associated with higher CAC volume and accelerated progression of CAC over time. Menopause increased CAC progression more in women with diabetes than in women without diabetes independent of age and other CVD risk factors known to worsen with menopause.

Glucose Management and the Sex Difference in Excess Cardiovascular Disease Risk in Long-Duration Type 1 Diabetes

PURPOSE OF REVIEW

The protection against CVD observed in women compared to men in the general population is essentially erased in type 1 diabetes. This review will discuss evidence regarding the role of glucose management on CVD risk by sex, with a particular focus on studies of long-duration type 1 diabetes of > 20 years.

RECENT FINDINGS

Across studies, women with type 1 diabetes have similar or worse glycemic control compared to men, despite higher rates of intensive insulin therapy. The association between HbA1c and CVD risk does not seem to differ by sex, but few studies have reported on sex-specific analyses. Beyond HbA1c, there is a lack of published data regarding the relationship between other aspects of glucose management and CVD risk by sex in type 1 diabetes. Glucose management factors do not seem to directly account for the increased CVD risk in women with type 1 diabetes, but may influence other risk factors that play a more direct role.

Gender specificity improves the early-stage detection of clear cell renal cell carcinoma based on methylomic biomarkers

AIM

The two genders are different ranging from the molecular to the phenotypic levels. But most studies did not use this important information. We hypothesize that the integration of gender information may improve the overall prediction accuracy.

MATERIALS & METHODS

A comprehensive comparative study was carried out to test the hypothesis. The classification of the stages I + II versus III + IV of the clear cell renal cell carcinoma samples was formulated as an example.

RESULTS & CONCLUSION

In most cases, female-specific model significantly outperformed both-gender model, as similarly for the male-specific model. Our data suggested that gender information is essential for building biomedical classification models and even a simple strategy of building two gender-specific models may outperform the gender-mixed model.