Candidate biomarkers as predictors of future kidney disease and cardiovascular dysfunction in adolescents with type 2 diabetes.

AIMS: Evaluate changes in circulating biomarkers as predictors of kidney disease, and cardiac/vascular dysfunction in participants from the Treatment Options for type 2 Diabetes in Adolescents and Youth (TODAY) study. METHODS: Candidate biomarkers were assessed annually in 507 participants over a mean follow-up of 6.9 ± 2.4 years. Moderate albuminuria was defined as urine albumin-to-creatinine ratio ≥ 30 mg/g and hyperfiltration as eGFR ≥ 135 mL/min/1.73 m2 at two consecutive visits. Echocardiography (n = 256) and pulse wave velocity (n = 193) were evaluated twice, 5 years apart. Adjusted Cox proportional hazard models and logistic regression models were used to examine associations between biomarkers and outcomes. RESULTS: At baseline, 35.7% were male, with a mean age 13.9 years, diabetes duration 7.8 months, and HbA1c 6.0%. Higher concentrations of E-selectin and proinsulin were associated with incident moderate albuminuria and hyperfiltration. Higher concentrations of FGF-23 were associated with lower risk of hyperfiltration and negatively correlated with eGFR. No candidate biomarkers predicted a decline in cardiac or vascular function. CONCLUSIONS: Circulating biomarkers of endothelial dysfunction and markers of ß-cell dysfunction and insulin sensitivity could be used in a more personalized risk assessment of kidney disease in youth-onset type 2 diabetes. However, biomarkers studied have limited value in predicting cardiac dysfunction or vascular stiffness.

The obesity paradox: Retinopathy, obesity, and circulating risk markers in youth with type 2 diabetes in the TODAY Study.

AIM: To understand the relationship of obesity and 27 circulating inflammatory biomarkers to the prevalence of non-proliferative diabetic retinopathy (NPDR) in youth with type 2 diabetes. METHODS: Youth with type 2 diabetes who participated in the TODAY (Treatment Options for Type 2 Diabetes in Adolescents and Youth) study were followed for 2-6.5 years. Digital fundus photographs were obtained in the last year of the study. Blood samples during the study were processed for inflammatory biomarkers, and these were correlated with obesity tertiles and presence of retinopathy. RESULTS: Higher BMI was associated with an increase in circulating levels of metabolic biomarkers including high sensitivity C-reactive protein (hsCRP), plasminogen activator inhibitor 1 (PAI-1), fibrinogen, LDL-cholesterol (LDL-C) and Apolipoprotein B (ApoB), tumor necrosis factor receptors 1 and 2 (TNFR-1 and -2), interleukin 6 (IL-6), E-selectin, and homocysteine, as well as a decrease in the metabolic risk markers HDL-cholesterol (HDLC), and insulin-like growth factor binding protein 1 (IGFBP-1). Although NPDR risk decreased with increasing obesity, it was not associated with any of the measured biomarkers. CONCLUSIONS: Circulating levels of measured biomarkers did not elucidate the "obesity paradox" of decreased NPDR in the most obese participants in the TODAY study. TRIAL REGISTRATION: clinicaltrials.govNCT00081328.

Relationship between Arterial Stiffness and Subsequent Cardiac Structure and Function in Young Adults with Youth-Onset Type 2 Diabetes: Results from the TODAY Study.

BACKGROUND: Higher arterial stiffness may contribute to future alterations in left ventricular systolic and diastolic function. We tested this hypothesis in individuals with youth-onset type 2 diabetes from the Treatment Options for Type 2 Diabetes in Adolescents and Youth (TODAY) study. METHODS: Arterial stiffness (pulse wave velocity [carotid-femoral, femoral-foot, and carotid-radial], augmentation index, brachial distensibility) was measured in 388 participants with type 2 diabetes (mean age, 21 years; diabetes duration, 7.7 ± 1.5 years). To reflect overall (composite) vascular stiffness, the five arterial stiffness measures were aggregated. An echocardiogram was performed in the same cohort 2 years later. Linear regression models assessed whether composite arterial stiffness was associated with left ventricular mass index or systolic and diastolic function, independent of age, sex, race/ethnicity, current cigarette smoking, and long-term exposure (time-weighted mean values over 9.1 years) of hemoglobin A1c, blood pressure, and body mass index. Interactions among arterial stiffness and time-weighted mean hemoglobin A1c, blood pressure, and body mass were also examined. RESULTS: After adjustment, arterial stiffness remained significantly associated with left ventricular mass index and diastolic function measured by mitral valve E/Em, despite attenuation by time-weighted mean body mass index. A significant interaction revealed a greater adverse effect of composite arterial stiffness on mitral valve E/Em among participants with higher levels of blood pressure over time. Arterial stiffness was unrelated to left ventricular systolic function. CONCLUSIONS: The association of higher arterial stiffness with future left ventricular diastolic dysfunction suggests the path to future heart failure may begin early in life in this setting of youth-onset type 2 diabetes. TRIAL REGISTRATION: ClinicalTrials.gov NCT00081328.

Cardiovascular risk factor progression in adolescents and young adults with youth-onset type 2 diabetes.

AIMS: Youth-onset type 2 diabetes (T2D) confers a high risk of early adverse cardiovascular morbidity. We describe the cumulative incidence and prevalence of cardiovascular risk factors over time and examine relationships with diabetes progression in young adults with youth-onset T2D from the Treatment Options for type 2 Diabetes in Adolescents and Youth (TODAY) study. METHODS: Longitudinal data was used to evaluate the relationships between hypertension, LDL-C dyslipidemia, hypertriglyceridemia, and smoking with risk factors in 677 participants. RESULTS: Baseline mean age was 14 ± 2 years and mean follow-up 10.2 ± 4.5 years. The 14-year cumulative incidence of hypertension, LDL-C dyslipidemia, and hypertriglyceridemia was 59%, 33%, and 37% respectively. Average prevalence of reported smoking was 23%. Male sex, non-Hispanic white race/ethnicity, obesity, poor glycemic control, lower insulin sensitivity, and reduced beta-cell function were significantly associated with an unfavorable risk profile. At end of follow-up, 54% had ≥2 cardiovascular risk factors in addition to T2D. CONCLUSIONS: Cardiovascular risk factor incidence and prevalence was high over a decade of follow-up in young adults with youth-onset T2D. Glucose control and management of cardiovascular risk factors is critical in youth with T2D for prevention of cardiovascular morbidity and mortality.

Cardiac Biomarkers in Youth with Type 2 Diabetes Mellitus: Results from the TODAY Study.

OBJECTIVES: To examine cardiac biomarkers over time in youth-onset type 2 diabetes, and relate serum concentrations to cardiovascular disease risk factors, and left ventricular structure and function. STUDY DESIGN: TODAY (Treatment Options for type 2 Diabetes in Adolescents and Youth) was a multicenter randomized trial of 3 treatments including 521 participants with type 2 diabetes, aged 10-17 years, and with 2-6 years of follow-up. Participants were 36% male, obese, and ethnically diverse. Annual serum concentrations of brain natriuretic peptide, troponin, tumor necrosis factor (TNF)-α, receptors 1 and 2 were related to blood pressure, body mass index, hemoglobin A1c, and left ventricular ejection fraction, diastolic function, relative wall thickness, and mass. RESULTS: Elevated concentrations of brain natriuretic peptide (≥100 pg/mL), TNF-α (≥5.6 pg/mL) and troponin (≥0.01 ng/mL), were present in 17.8%, 18.3%, and 34.2% of the cohort, respectively, at baseline, and in 15.4%, 17.1%, and 31.1% at the end of the study, with wide variability over time, without persistence in individuals or clear relationship to glycemia or cardiovascular structure/function. TNF receptors concentrations were increased at baseline and not significantly different from end-of-study concentrations. Adverse echocardiographic measures were more likely in the highest TNF receptor tertile (all P < .05): higher left ventricular mass (39.3 ± 9.0 g/m2.7), left atrial internal dimension (3.7 ± 0.4 cm) and E/Em ratio, a measure of diastolic dysfunction (6.2 ± 1.9). After adjustment for body mass index, these relationships were no longer significant. CONCLUSIONS: Elevated serum concentrations of cardiac biomarkers were common in youth with type 2 diabetes, but their clinical significance is unclear and will require further long-term study. TRIAL REGISTRATION: ClinicalTrials.govNCT00081328.

Longitudinal Correlates of Health Risk Behaviors in Children and Adolescents with Type 2 Diabetes.

OBJECTIVES: To characterize, during a 2-year period, the proportion of youth with type 2 diabetes (T2D) enrolled in the Treatment Options for Type 2 Diabetes in Adolescents and Youth study that reported ever at least trying smoking cigarettes and/or drinking alcohol. STUDY DESIGN: Longitudinal data were examined for participants with T2D ages 10-18 years at baseline. Youth psychosocial, parent/family, environmental, and biological correlates of trying health risk behaviors were tested via cross-sectional multivariate models at each time point. Longitudinal models were explored for selected factors. RESULTS: Data were obtained from the Treatment Options for Type 2 Diabetes in Adolescents and Youth study's ethnically diverse participants at baseline (N=644), 6-month (N=616), and 24-month (N=543) assessments. The percentage of youth ever trying only smoking remained stable at 4%; only drinking alcohol increased from 17% to 26%, and both smoking and drinking increased from 10% to 18% during the 2-year period. Factors related to trying health risk behaviors were older age, male sex, non-Hispanic white race-ethnicity, lower grades, more depressive symptoms, and stressful life events. Depressive symptoms, stressful life events, and body mass index Z-score (the latter with smoking only) were related to engagement in health risk behaviors over time. CONCLUSIONS: Youth with T2D who are already at risk for health complications and who reported engaging in activities that further increase the likelihood of life-threatening morbidities were characterized. Although most correlates of trying these risk behaviors are nonmodifiable, intervention efforts may need to focus on potentially modifiable factors, such as depressive symptoms and lower grades.

Metabolic effects of obesity causing disease in childhood.

PURPOSE OF REVIEW: Childhood obesity is rising to epidemic proportions throughout the world, and much emphasis has been placed on the long-term consequences that can result later, in adulthood. This article reviews the metabolic consequences of obesity that can manifest as disease during the childhood years. RECENT FINDINGS: Obese children suffer from many disease processes once thought to affect only adults. They can have type 2 diabetes mellitus, and potentially early ß cell failure with rapid progression to an insulin requirement. There is a high prevalence of fatty liver disease in obese children, and complications such as steatohepatitis and even cirrhosis can develop during childhood. Visceral fat has been shown to have many different properties than subcutaneous fat, and children with central adiposity can develop the metabolic syndrome with insulin resistance, hypertension, and dyslipidemia. Hyperandrogenism, sleep disturbances, and many types of orthopedic complications can also develop in young children. SUMMARY: Physicians should not only warn obese children and their families about the long-term consequences of obesity for which they are at risk in adulthood, they should also screen for the many diseases that may already be present.

Increased prevalence of abnormal glucose tolerance among obese siblings of children with type 2 diabetes.

OBJECTIVE: To test the hypothesis that overweight siblings of children with type 2 diabetes mellitus (T2DM) have a higher prevalence of abnormal glucose tolerance (AGT) compared with other overweight children. STUDY DESIGN: This was a cross-sectional study of overweight (body mass index [BMI] >or= 95(th) percentile) subjects, age 8 to 17 years, with at least 1 sibling age >or= 12 years. The primary outcome was AGT, as assessed by the oral glucose tolerance test (2-hour glucose >or= 140 mg/dL). The secondary outcome was insulin resistance by homeostasis model assessment (HOMA). RESULTS: The sibling (n=20) and control (n=42) groups were similar in terms of age, sex, racial distribution (largely African American), pubertal status, and BMI. The prevalence of AGT in the sibling group was 40.0% (n=8), compared with 14.3% (n=6) in controls (P= .048, Fisher exact test; unadjusted odds ratio=4.0; 95% confidence interval=1.2 to 13.5). Univariate analysis did not identify confounders for either outcome. There were no significant differences in HOMA or hemoglobin A1c between the 2 groups. CONCLUSIONS: Overweight siblings of children with T2DM had 4 times greater odds of having AGT compared with other overweight children. This group may represent a particularly high-risk population to target for screening and pediatric T2DM prevention.

Insulin-like growth factor binding protein-3 is a novel mediator of apoptosis in insulin-secreting cells.

Insulin-like growth factor binding protein-3 (IGFBP-3) is emerging as a critical regulator of cell survival. There has been no study which directly examined the potential role for this major growth factor in the programmed cell death (apoptosis) of insulin-secreting cells. To determine whether IGFBP-3 mediates apoptosis in insulin-secreting cells, we performed a rigorous series of experiments with the rat insulinoma (RIN) cell line m5F and the hamster insulin-secreting tumor (HIT) T-15. Within 24 h exogenous IGFBP-3 induced significant DNA fragmentation in RIN and HIT cells, at doses ranging from 4.4 to 2000 ng/ml (P<0.05) without a classic dose-response relationship. DNA fragmentation induced by rhIGFBP-3 occurred in the presence of immunoglobulin to block the type 1 IGF receptor. As detected by flow cytometry for Annexin V exposure to the cell surface, rhIGFBP-3 treatment doubled the proportion of apoptotic HIT cells from 1.7 +/- 0.4% (serum-free control) to 3.4 +/- 0.2% (P<0.02), an effect completely reversed by co-treatment with 1000 ng/ml rhIGF-I. Immunofluorescent microscopy disclosed that pro-inflammatory Th1 cytokines increased intranuclear aggregation of endogenous IGFBP-3. Cytokine-induced DNA fragmentation was completely blocked by relatively brief pre-treatment with antisense IGFBP-3 phosphorothioate oligodeoxynucleotides. In conclusion, we have presented the first evidence that IGFBP-3 contributes to cytokine-mediated apoptosis in insulin-secreting cells.