Cardiovascular function/dysfunction in adolescents with type 1 diabetes

Pediatric Type 1 Diabetes: Is Age at Onset a Determining Factor in Advanced Hybrid Closed-Loop Insulin Therapy?

BACKGROUND

The integration of continuous glucose monitoring systems with insulin infusion pumps has shown improved glycemic control, with improvements in hyperglycemia, hypoglycemia, Hb1Ac, and greater autonomy in daily life. These have been most studied in adults and there are currently not many articles published in the pediatric population that establish their correlation with age of debut.

METHODS

Prospective, single-study. A total of 28 patients (mean age 12 ± 2.43 years, 57% male, duration of diabetes 7.84 ± 2.46 years) were included and divided into two groups according to age at T1D onset (≤4 years and >4 years). Follow-up for 3 months, with glucometric variables extracted at different cut-off points after the start of the closed-loop (baseline, 1 month, 3 months).

RESULTS

Significant improvement was evidenced at 1 month and 3 months after closed-loop system implantation, with better glycemic control in the older age group at baseline at TIR (74.06% ± 6.37% vs. 80.33% ± 7.49% at 1 month, p < 0.003; 71.87% ± 6.58% vs. 78.75% ± 5.94% at 3 months, p < 0.009), TAR1 (18.25% ± 4.54% vs. 14.33% ± 5.74% at 1 month, p < 0.006; 19.87% ± 5.15% vs. 14.67% ± 4. 36% at 3 months, p < 0.009) and TAR2 (4.75% ± 2.67% vs. 2.75% ± 1.96% at 1 month, p = 0.0307; 5.40% ± 2.85% vs. 3% ± 2.45% at 3 months, p < 0.027).

CONCLUSIONS

the use of automated systems such as the MiniMedTM780G system brings glucometric results closer to those recommended by consensus, especially in age at T1D onset >4 years. However, the management in pediatrics continues to be a challenge even after the implementation of these systems, especially in terms of hyperglycemia and glycemic variability.

Cerebral blood flow is lower in youth with type 2 diabetes compared to obese controls: A pilot study

AIM

The cerebral vasculature may be susceptible to the adverse effects of type 2 diabetes. In this pilot study, we compared cerebral blood flow (CBF) in youth with type 2 diabetes to obese, euglycemic controls, and explored the association between CBF and a non-invasive measure of atherosclerosis, carotid intima-medial thickness (IMT).

METHODS

Global and regional CBF were compared between youth with type 2 diabetes (mean age 16.7 ± 2.0 years, n = 20) and age, race, and sex similar obese youth without diabetes (17.4 ± 1.9 years, n = 19) using arterial spin labeling magnetic resonance imaging. Mean CBF values were compared between groups. Voxel-wise results were evaluated for statistical significance (p < 0.05) after adjustment for multiple comparisons. Carotid IMT in the type 2 diabetes group was correlated with CBF.

RESULTS

Compared to obese controls, the type 2 diabetes group had significantly lower global CBF (49.7 ± 7.2 vs. 63.8 ± 11.5 ml/gm/min, p < 0.001). Significantly lower CBF was observed in multiple brain regions for the type 2 diabetes group, while no regions with higher CBF were identified. In the type 2 diabetes group, carotid IMT was inversely correlated with CBF, both globally (r = -0.70, p = 0.002) and in regional clusters.

CONCLUSIONS

In this pilot study, lower CBF was seen in youth with type 2 diabetes compared to youth with obesity and IMT was inversely correlated with CBF. Cerebrovascular impairment may be present in youth with type 2 diabetes. These findings could represent a mechanistic link to explain previously reported brain volume and neurocognitive differences.

Cardiovascular risk and heart rate variability in young adults with type 2 diabetes and arterial stiffness: The SEARCH for Diabetes in Youth Study

AIMS

To evaluate cardiovascular risk factors and heart rate variability (HRV) in young adults with type 2 diabetes and arterial stiffness and to explore the relationship between HRV and arterial stiffness.

METHODS

We studied 185 young adults with youth-onset T2D enrolled in the SEARCH for Diabetes in Youth Study. Cardiovascular risk factors and HRV were compared between individuals with and without type 2 diabetes and arterial stiffness (defined as a pulse wave velocity greater than the 90th percentile of healthy controls, >6.767 m/s). Semiparametric regression evaluated the independent relationship between HRV and PWV.

RESULTS

Participants with T2D and arterial stiffness were more likely to be older, non-Hispanic Black, have higher systolic and diastolic blood pressure, greater adiposity and obesity-related dyslipidemia (higher triglycerides and lower HDLC). Participants with T2D and arterial stiffness also had lower overall HRV (lower SDNN) with parasympathetic loss (lower RMSSD and PNN50), p < 0.05. Lower HRV tended to be but was not significantly associated with arterial stiffness after adjustment for age, race/ethnicity, sex and cardiovascular risk factors (beta coefficient = -1.11, p = 0.08).

CONCLUSIONS

Youth with T2D and arterial stiffness have a worse cardiovascular risk profile, specifically risk factors related to the metabolic syndrome and lower HRV.

The changing face of paediatric diabetes

The purpose of this review is to provide an update on the changing face of paediatric type 1 diabetes and type 2 diabetes. Paediatric diabetes is on the rise, with extensive research dedicated to understanding its pathophysiology, comorbidities and complications. As obesity continues to increase among all youth, differentiating between type 1 diabetes and type 2 diabetes has become increasingly difficult but remains important for optimising treatment, anticipating complications and predicting disease risk. Novel treatments are emerging, with the ultimate goal being to achieve glycaemic control, limit weight gain, improve quality of life and reduce comorbidities. In this review, we focus on updates regarding the epidemiology, clinical presentation, comorbidities and complications of paediatric type 1 diabetes and type 2 diabetes and conclude with current and emerging treatments.

"Metabolic and cardiovascular response to exercise in patients with type 1 diabetes"

PURPOSE

Physical activity is an effective therapeutic tool for cardiovascular risk prevention. However, exercise aerobic capacity of patients with type 1 diabetes (T1DM) has not been thoroughly investigated. Aim of the present study is to evaluate exercise aerobic capacity in patients with T1DM compared to a normal control population.

METHODS

This observational study included 17 T1DM patients and 17 matched healthy volunteers. Cardiopulmonary exercise test (CPET) was conducted on an electronically-braked cycle ergometer. Blood samples were collected for evaluation of glycemia and lactate levels.

RESULTS

Mean oxygen uptake at peak exercise (V'O_2,peak) was significantly lower in T1DM subjects (V'O_2,peak T1DM 2200 ± 132ml/min vs V'O_2,peak Healthy subjects of 2659 ± 120 ml/min p = 0.035). Cardiovascular response analysis did not show statistically significant differences. Respiratory exchange ratio (RER) was significantly higher in healthy subjects at peak exercise and at the first minute of recovery (p = 0.022, p = 0.024). Peak exercise lactate levels were significantly higher in healthy subjects. There was no statistical correlation between CPET results and diabetes-related parameters.

CONCLUSIONS

Patients affected by T1DM have a worse exercise tolerance than normal subjects. The two groups differed by RER which can be greatly influenced by the substrate type utilized to produce energy. Because of the impaired carbohydrate utilization, T1DM subjects may use a larger amount of lipid substrates, such hypothesis could be strengthened by the lower lactate levels found in T1DM group at peak exercise. The lack of correlation between exercise tolerance and disease-related variables suggests that the alterations found could be independent from the glycemic levels.

Youth with type 1 diabetes have worse strain and less pronounced sex differences in early echocardiographic markers of diabetic cardiomyopathy compared to their normoglycemic peers: A RESistance to InSulin in Type 1 ANd Type 2 diabetes (RESISTANT) Study

OBJECTIVE

Diabetic cardiomyopathy is a major cause of morbidity, but limited data are available on early cardiac abnormalities in type 1 diabetes (T1D). We investigated differences in myocardial strain in adolescents with and without T1D. We hypothesized that adolescents with T1D would have worse strain than their normoglycemic peers, which boys would have worse strain than girls, and that strain would correlate with glycemic control and adipokines.

METHODS

We performed fasting laboratory measures and echocardiograms with speckle tracking to evaluate traditional echocardiographic measures in addition to longitudinal (LS) and circumferential (CS) strain, and in adolescents (15±2years) with (19 boys; 22 girls) and without (16 boys; 32 girls) type 1 diabetes.

RESULTS

Compared to controls, adolescents with type 1 diabetes had significantly lower CS (-20.9 vs. -22.7%, p=0.02), but not LS (p=0.83). Boys with T1D had significantly lower LS than girls with T1D (-17.5 vs. -19.7%, p=0.047), adjusted for Tanner stage. The significant sex differences observed in indexed left ventricular mass, left end-diastolic volume, diastolic septal and posterior wall thickness in our controls were lacking in adolescents with T1D.

CONCLUSIONS

Our observations suggest that youth with T1D have worse myocardial strain than normoglycemic peers. In addition, the relatively favorable cardiac profile observed in girls vs. boys in the control group, was attenuated in T1D. These early cardiovascular changes in youth with T1D are concerning and warrant longitudinal and mechanistic studies.

Swimming training attenuates the morphological reorganization of the myocardium and local inflammation in the left ventricle of growing rats with untreated experimental diabetes

Diabetic cardiomyopathy is associated with cardiac remodeling, myocardial dysfunction, low-grade inflammation, and reduced cardiac adiponectin in patients with type 1 diabetes mellitus (T1DM). Alternatively, physical exercise is an important strategy for the management of diabetes. This study aimed to investigate the influence of low-intensity swimming training in cardiac cytokines, structural remodeling, and cardiomyocyte contractile dysfunction in growing rats with untreated experimental DM. Thirty-day-old male Wistar rats were divided into four groups (n=14, per group): sedentary control (SC), exercised control (EC), sedentary diabetic (SD), and exercised diabetic (ED). Diabetes was induced by streptozotocin (60 mg kg(-1), i.p.). Animals from exercised groups swam (5 days/week, 90 min/day, loading up to 5% body weight around the animal's chest) for 8 weeks. The left ventricle (LV) was removed for molecular, morphological, and cardiomyocyte mechanical analysis. Diabetic animals presented cardiac remodeling with myocardial histoarchitectural disorganization, fibrosis, and necrosis. The capillary density was lower in diabetic animals. LV cardiomyocytes from diabetic animals exhibited more prolonged time to the peak of contraction and time to half relaxation than those from control animals. The cardiac levels of interleukin 10, nitric oxide, and total and high molecular weight (HMW) adiponectin were significantly decreased in diabetic animals. Exercise training reduced the level of TNF-α, increased capillary density, and attenuated the histopathological parameters assessed in diabetic rats. In conclusion, the cardiac structural remodeling coexists with reduced levels of total and HMW adiponectin, inflammation, and cardiomyocyte contractility dysfunction in experimental DM. More important, low-intensity swimming training attenuates part of these pathological changes, indicating the beneficial role for exercise in untreated T1DM.

Insulin sensitivity and arterial stiffness in youth with type 1 diabetes: the SEARCH CVD study

AIMS

Decreased insulin sensitivity is a cardiovascular risk factor (CVRF) in youth with type 1 diabetes (T1D). Whether baseline insulin sensitivity is independently associated with changes in early arterial stiffness (pulse wave velocity (PWV)) over time in youth with T1D is not known.

METHODS

Two hundred ninety-eight youth with T1D in the SEARCH CVD study had PWV measured~five years apart. Insulin sensitivity and other CVRFs were measured at baseline. The association between baseline insulin sensitivity with PWV over time was explored using linear mixed models. Models were adjusted for baseline age, sex and race, with subsequent adjustment for CVRFs.

RESULTS

There was a significant interaction (p=0.0326) between baseline insulin sensitivity and time on PWV, independent of CVRFs, indicating that higher insulin sensitivity levels were associated with lower rate of change in PWV over time. Other significant predictors of PWV change were baseline age [β=0.007 (p=0.03) increase in logPWV/year increase in age] and mean arterial blood pressure (MAP) [β=0.005 (p<0.01) increase in logPWV/mmHg increase in MAP] and smoking status (current vs. never smoker).

CONCLUSIONS

Lower insulin sensitivity at baseline appears to be an important risk factor for increased arterial stiffness over time in youth with T1D. This identifies a potentially modifiable therapeutic target.

Type 2 diabetes and cardiovascular disease in women

Cardiovascular disease is the leading cause of death in both men and women. This is also true for patients with diabetes. In general, differences between the sexes are present in several areas, such as epidemiology, pathophysiology, diagnostics, treatment response and prognosis, as well as the way in which disease is experienced and expressed. Cardiovascular disease presents later in life in women, who are therefore more likely to suffer from comorbidities. However, this age-related difference is attenuated in women with diabetes, who suffer their first myocardial infarction at about the same age as men with diabetes. Diabetes mellitus increases the risk of cardiovascular disease by three to four times in women and two to three times in men, after adjusting for other risk factors. This paper describes the differences in cardiovascular disease in men and women and the special situation of women with type 2 diabetes when it comes to risk factors, symptoms and the setting of acute coronary syndromes. Furthermore, it highlights the importance of sex-specific analyses in clinical research to improve our knowledge of cardiovascular disease in women in general and in women with diabetes in particular. The importance of taking sex into account when treating women and men at risk of cardiovascular disease is discussed.

Organ-based response to exercise in type 1 diabetes

While significant research has clearly identified sedentary behavior as a risk factor for type 2 diabetes and its subsequent complications, the concept that inactivity could be linked to the complications associated with type 1 diabetes (T1D) remains underappreciated. This paper summarizes the known effects of exercise on T1D at the tissue level and focuses on the pancreas, bone, the cardiovascular system, the kidneys, skeletal muscle, and nerves. When possible, the molecular mechanisms underlying the benefits of exercise for T1D are elucidated. The general benefits of increased activity on health and the barriers to increased exercise specific to people with T1D are discussed.

Cardiovascular autonomic nervous system function and aerobic capacity in type 1 diabetes

Impaired cardiovascular autonomic nervous system (ANS) function has been reported in type 1 diabetes (T1D) patients. ANS function, evaluated by heart rate variability (HRV), systolic blood pressure variability (SBPV), and baroreflex sensitivity (BRS), has been linked to aerobic capacity (VO_2peak) in healthy subjects, but this relationship is unknown in T1D. We examined cardiovascular ANS function at rest and during function tests, and its relations to VO_2peak in T1D individuals. Ten T1D patients (34 ± 7 years) and 11 healthy control (CON; 31 ± 6 years) age and leisure-time physical activity-matched men were studied. ANS function was recorded at rest and during active standing and handgrip. Determination of VO_2peak was obtained with a graded cycle ergometer test. During ANS recordings SBPV, BRS, and resting HRV did not differ between groups, but alpha1 responses to maneuvers in detrended fluctuation analyses were smaller in T1D (active standing; 32%, handgrip; 20%, medians) than in CON (active standing; 71%, handgrip; 54%, p < 0.05). VO_2peak was lower in T1D (36 ± 4 ml kg⁻¹ min⁻¹) than in CON (45 ± 9 ml kg⁻¹ min⁻¹, p < 0.05). Resting HRV measures, RMSSD, HF, and SD1 correlated with VO_2peak in CON (p < 0.05) and when analyzing groups together. These results suggest that T1D had lower VO_2peak, weaker HRV response to maneuvers, but not impaired cardiovascular ANS function at rest compared with CON. Resting parasympathetic cardiac activity correlated with VO_2peak in CON but not in T1D. Detrended fluctuation analysis could be a sensitive detector of changes in cardiac ANS function in T1D.

Cardiovascular disease in children and adolescents with diabetes: where are we, and where are we going?

The increasing prevalence of type 1 and type 2 diabetes mellitus combined with advancement in early detection of cardiovascular disease (CVD) has placed CVD as a significant concern for preventative pediatric medicine. The public health burden of type 2 diabetes is predicted to parallel increasing obesity in children with a projected increase of early CVD in adulthood. In this article, we review practice guidelines for cardiovascular health in children and adolescents with diabetes and data on which they are based. We then focus on imaging modalities that are promising tools to expand our understanding of the cardiovascular risk imposed on youths with diabetes.

Time-dependent alterations in rat macrovessels with type 1 diabetes

Vascular complications are associated with the progressive severity of diabetes, resulting in significant morbidity and mortality. This study quantifies functional vascular parameters and macrovascular structure in a rat model of type 1 diabetes. While there was no difference in the systemic arterial elastance (Ea) with 50 days of diabetes, changes were noted in the aorta and femoral artery including increased tunica media extracellular matrix content, decreased width of both the media and individual smooth muscle cell layers, and increased incidence of damaged mitochondria. Extracellular matrix proteins and elastin levels were significantly greater in the aorta of diabetic animals. These differences correlated with diminished matrix metalloprotease activity in the aorta of the diabetic animals. In conclusion, diabetes significantly altered the structure and ultrastructure of the aorta and femoral artery before systemic changes in arterial elastance could be detected.