T-Cell Expression and Release of Kidney Injury Molecule-1 in Response to Glucose Variations Initiates Kidney Injury in Early Diabetes

Half of the mortality in diabetes is seen in individuals <50 years of age and commonly predicted by the early onset of diabetic kidney disease (DKD). In type 1 diabetes, increased urinary albumin-to-creatinine ratio (uACR) during adolescence defines this risk, but the pathological factors responsible remain unknown. We postulated that early in diabetes, glucose variations contribute to kidney injury molecule-1 (KIM-1) release from circulating T cells, elevating uACR and DKD risk. DKD risk was assigned in youth with type 1 diabetes (n = 100; 20.0 ± 2.8 years; males/females, 54:46; HbA_1c 66.1 [12.3] mmol/mol; diabetes duration 10.7 ± 5.2 years; and BMI 24.5 [5.3] kg/m²) and 10-year historical uACR, HbA_1c, and random blood glucose concentrations collected retrospectively. Glucose fluctuations in the absence of diabetes were also compared with streptozotocin diabetes in apolipoprotein E ^-/- mice. Kidney biopsies were used to examine infiltration of KIM-1-expressing T cells in DKD and compared with other chronic kidney disease. Individuals at high risk for DKD had persistent elevations in uACR defined by area under the curve (AUC; uACR_AUC0-10yrs, 29.7 ± 8.8 vs. 4.5 ± 0.5; P < 0.01 vs. low risk) and early kidney dysfunction, including ∼8.3 mL/min/1.73 m² higher estimated glomerular filtration rates (modified Schwartz equation; P_adj < 0.031 vs. low risk) and plasma KIM-1 concentrations (∼15% higher vs. low risk; P < 0.034). High-risk individuals had greater glycemic variability and increased peripheral blood T-cell KIM-1 expression, particularly on CD8⁺ T cells. These findings were confirmed in a murine model of glycemic variability both in the presence and absence of diabetes. KIM-1⁺ T cells were also infiltrating kidney biopsies from individuals with DKD. Healthy primary human proximal tubule epithelial cells exposed to plasma from high-risk youth with diabetes showed elevated collagen IV and sodium-glucose cotransporter 2 expression, alleviated with KIM-1 blockade. Taken together, these studies suggest that glycemic variations confer risk for DKD in diabetes via increased CD8⁺ T-cell production of KIM-1.

Advanced glycation end products as predictors of renal function in youth with type 1 diabetes

To examine if skin autofluorescence (sAF) differed in early adulthood between individuals with type 1 diabetes and age-matched controls and to ascertain if sAF aligned with risk for kidney disease. Young adults with type 1 diabetes (N = 100; 20.0 ± 2.8 years; M:F 54:46; FBG-11.6 ± 4.9 mmol/mol; diabetes duration 10.7 ± 5.2 years; BMI 24.5(5.3) kg/m²) and healthy controls (N = 299; 20.3 ± 1.8 years; M:F-83:116; FBG 5.2 ± 0.8 mmol/L; BMI 22.5(3.3) kg/m²) were recruited. Skin autofluorescence (sAF) and circulating AGEs were measured. In a subset of both groups, kidney function was estimated by GFR_{CKD-EPI CysC} and uACR, and DKD risk defined by uACR tertiles. Youth with type 1 diabetes had higher sAF and BMI, and were taller than controls. For sAF, 13.6% of variance was explained by diabetes duration, height and BMI (P_model = 1.5 × 10^-12). In the sub-set examining kidney function, eGFR and sAF were higher in type 1 diabetes versus controls. eGFR and sAF predicted 24.5% of variance in DKD risk (P_model = 2.2 × 10^-9), which increased with diabetes duration (51%; P_model < 2.2 × 10^-16) and random blood glucose concentrations (56%; P_model < 2.2 × 10^-16). HbA_1C and circulating fructosamine albumin were higher in individuals with type 1 diabetes at high versus low DKD risk. eGFR was independently associated with DKD risk in all models. Higher eGFR and longer diabetes duration are associated with DKD risk in youth with type 1 diabetes. sAF, circulating AGEs, and urinary AGEs were not independent predictors of DKD risk. Changes in eGFR should be monitored early, in addition to uACR, for determining DKD risk in type 1 diabetes.

A safety and pharmacodynamics study of temelimab, an antipathogenic human endogenous retrovirus type W envelope monoclonal antibody, in patients with type 1 diabetes

AIM

To report the first study of temelimab, a monoclonal antibody neutralizing the pathogenic human endogenous retrovirus type W envelope, in patients with type 1 diabetes (T1D).

MATERIALS AND METHODS

This double-blind, placebo-controlled, randomized clinical trial recruited adult patients with T1D within 4 years postdiagnosis and remaining C-peptide secretion. Sixty-four patients were randomized (2:1) to monthly temelimab 6 mg/kg or placebo during 24 weeks followed by a 24-week, open-label extension, during which all patients received temelimab. The primary objective was the safety and tolerability of temelimab. The secondary objective was to assess the pharmacodynamics response such as C-peptide levels, insulin use, HbA1c, hypoglycaemia and autoantibodies.

RESULTS

Temelimab was well tolerated without any group difference in the frequency or severity of adverse events. Concerning exploratory endpoints, there was no difference in the levels of C-peptide, insulin use or HbA1c between treatment groups at weeks 24 and 48. The frequency of hypoglycaemia events was reduced with temelimab (P = 0.0004) at week 24 and the level of anti-insulin antibodies was lower with temelimab (P < 0.01); the other autoantibodies did not differ between groups.

CONCLUSIONS

Temelimab appeared safe in patients with T1D. Pharmacodynamics signals (hypoglycaemia and anti-insulin antibodies) under temelimab were observed. Markers of β-cell functions were not modified by treatment. These results need to be further explored in younger patients with T1D with earlier disease onset.

Diabetes care: addressing psychosocial well-being in young adults with a newly developed assessment tool

BACKGROUND

Psychosocial assessment should be part of clinic visits for people with diabetes mellitus (DM).

AIMS

To assess the usage and acceptance of a diabetes psychosocial assessment tool (DPAT) and to profile the clinical and psychosocial characteristics of young people with diabetes.

METHODS

Over a 12-month period, young adults (18-25 years) attending diabetes clinic were offered DPAT. The tool embeds validated screening tools including the Problem Areas in Diabetes 20 (PAID-20) questionnaire, the Patient Health Questionnaire-4 (PHQ-4) and the World Health Organization Well-Being Index-5 (WHO-5). Baseline clinical data were collected and questions regarding social support, body image, eating concerns, hypoglycaemia and finances were included.

RESULTS

Over the 12 month, the form was offered to 155 participants (64.6% of eligible attendees). The majority (96.1%) had type 1 DM with a mean duration of 10.5 (±5.3 SD) years. Average glycated haemoglobin (HbA1c) was 8.7% (±1.5 SD) (or 71.2 mmol/mol ±16.5 SD). Severe diabetes-related distress (PAID-20 ≥ 40) was found in 19.4%. Low WHO-5 scores (28-50 points) were seen in 14.8%. PHQ-4 identified 25.8% with anxiety and 16.1% with depression. Significant weight, shape and eating concerns were identified in 27.1, 26.6 and 28.4%, respectively. Serious hypoglycaemia concerns were raised by 4.5%.

CONCLUSION

DPAT revealed a high prevalence of psychosocial stress among young adults with DM. The tool was easy to use and accepted by patients and may aid streamlining referrals to relevant members of a multidisciplinary team.

Living Well with Diabetes: a randomized controlled trial of a telephone-delivered intervention for maintenance of weight loss, physical activity and glycaemic control in adults with type 2 diabetes

BACKGROUND

By 2025, it is estimated that approximately 1.8 million Australian adults (approximately 8.4% of the adult population) will have diabetes, with the majority having type 2 diabetes. Weight management via improved physical activity and diet is the cornerstone of type 2 diabetes management. However, the majority of weight loss trials in diabetes have evaluated short-term, intensive clinic-based interventions that, while producing short-term outcomes, have failed to address issues of maintenance and broad population reach. Telephone-delivered interventions have the potential to address these gaps.

METHODS/DESIGN

Using a two-arm randomised controlled design, this study will evaluate an 18-month, telephone-delivered, behavioural weight loss intervention focussing on physical activity, diet and behavioural therapy, versus usual care, with follow-up at 24 months. Three-hundred adult participants, aged 20-75 years, with type 2 diabetes, will be recruited from 10 general practices via electronic medical records search. The Social-Cognitive Theory driven intervention involves a six-month intensive phase (4 weekly calls and 11 fortnightly calls) and a 12-month maintenance phase (one call per month). Primary outcomes, assessed at 6, 18 and 24 months, are: weight loss, physical activity, and glycaemic control (HbA1c), with weight loss and physical activity also measured at 12 months. Incremental cost-effectiveness will also be examined. Study recruitment began in February 2009, with final data collection expected by February 2013.

DISCUSSION

This is the first study to evaluate the telephone as the primary method of delivering a behavioural weight loss intervention in type 2 diabetes. The evaluation of maintenance outcomes (6 months following the end of intervention), the use of accelerometers to objectively measure physical activity, and the inclusion of a cost-effectiveness analysis will advance the science of broad reach approaches to weight control and health behaviour change, and will build the evidence base needed to advocate for the translation of this work into population health practice.

TRIAL REGISTRATION

ACTRN12608000203358.

Improvement of left ventricular function by lifestyle intervention in obesity: contributions of weight loss and reduced insulin resistance

AIMS/HYPOTHESIS

Weight excess and insulin resistance mediate the link between obesity and left ventricular dysfunction. We investigated the effect and mechanisms of lifestyle modification on left ventricular function changes in obese patients.

METHODS

Reduction of body weight and insulin resistance was sought using a behavioural intervention programme including dietary restrictions and exercise training in 261 patients (age 45 +/- 13 years) with BMI >or=30 kg/m(2), no history of cardiac disease and a normal stress echocardiogram. Each patient underwent echocardiographic measurement of myocardial deformation and velocity at baseline and at 6 month follow-up.

RESULTS

Improvements in left ventricular systolic and diastolic function were demonstrated only in patients with significant reduction of weight and/or insulin resistance. Left ventricular improvement was less frequent in patients with diabetes than in those without (52% vs 82% for strain, 50% vs 81% for strain rate and 59% vs 80% for peak early diastolic myocardial velocity). The independent predictors of improved left ventricular systolic function (increase in strain) were: weight reduction (beta = 0.14, p < 0.05), decrease in the HOMA insulin resistance index (beta = 0.20, p < 0.005) and absence of diabetes (beta = 0.18, p < 0.02). A decrease in HbA(1c) also predicted improvement of left ventricular diastolic function (beta = 0.26, p < 0.001). There was a parallel increment in exercise capacity with intervention and increase in strain was independently correlated with increase in VO(2) (beta = 0.13, p < 0.04).

CONCLUSIONS/INTERPRETATION

Effective lifestyle modifications in obese patients improve left ventricular systolic and diastolic function, but appear less effective with co-existing diabetes. The reversal of left ventricular function abnormalities is associated with reduction of both weight and insulin resistance, and is accompanied by an increase in cardiorespiratory fitness.

Effect of weight loss due to lifestyle intervention on subclinical cardiovascular dysfunction in obesity (body mass index >30 kg/m2)

Subclinical myocardial and vascular dysfunctions occur in subjects with obesity. We investigated whether these changes were reversible with weight loss due to lifestyle intervention. Quantitative assessment of myocardial and vascular functions was performed at baseline and after a minimum of 8 weeks of a lifestyle intervention program in 106 subjects with significant risk factors but no history of cardiovascular disease and normal ejection fractions. Myocardial function was assessed using strain rate, strain, regional myocardial systolic velocity, and diastolic velocity (e(m)). Myocardial reflectivity was assessed by calibrated integrated backscatter. Vascular function was assessed using brachial arterial reactivity and arterial compliance. Exercise capacity was measured by peak oxygen consumption per unit time (VO(2)). Weight loss (-4.5 +/- 2.0%) was achieved by 48 subjects, and 58 maintained or increased weight (+1 +/- 1.5%, p <0.001). Compared with the stable weight group, the weight loss group showed significant improvement in brachial arterial reactivity (8.6 +/- 4.9% vs 6.7 +/- 4.9%, p <0.05), e(m) (6.4 +/- 1.9 vs 5.5 +/- 1.9 cm/s, p <0.01), and reflectivity (calibrated integrated backscatter, 18.3 +/- 4.9 vs 16.2 +/- 5.2 dB, p <0.01). The magnitude of weight change correlated with changes in e(m) (r = 0.36) and calibrated integrated backscatter (r = 0.33). The change in e(m) correlated with peak VO(2) (r = 0.38, p <0.001) and was an independent predictor for peak VO(2) even after adjustment for age and body mass index in a multivariate model (R(2) = 0.45, p <0.001). Weight loss was not associated with a significant change in systolic parameters (regional myocardial systolic velocity, global strain, and strain rate) or arterial compliance.

Association of subclinical right ventricular dysfunction with obesity

OBJECTIVES

The purpose of this research was to identify the determinants of right ventricular (RV) dysfunction in overweight and obese subjects.

BACKGROUND

Right ventricular dysfunction in obese subjects is usually ascribed to comorbid diseases, especially obstructive sleep apnea. We used tissue Doppler imaging to identify the determinants of RV dysfunction in overweight and obese subjects.

METHODS

Standard and tissue Doppler echocardiography was performed in 112 overweight (body mass index [BMI] 25 to 29.9 kg/m2) or obese (BMI >30 kg/m2) subjects and 36 referents (BMI <25 kg/m2), including 22 with obstructive sleep apnea but no obesity. Tissue Doppler was used to measure RV systolic (s(m)) and diastolic (e(m)) velocities and strain indexes.

RESULTS

Obese subjects with BMI >35 kg/m2 had reduced RV function compared with referent subjects, evidenced by reduced s(m) (6.5 +/- 2.4 cm/s vs. 10.2 +/- 1.5 cm/s, p < 0.001), peak strain (-21 +/- 4% vs. -28 +/- 4%, p < 0.001), peak strain rate (-1.4 +/- 0.4 s(-1) vs. -2.0 +/- 0.5 s(-1), p < 0.001), and e(m) (-6.8 +/- 2.4 cm/s vs. -10.3 +/- 2.5 cm/s, p < 0.001), irrespective of the presence of sleep apnea. Similar but lesser degrees of reduced systolic function (p < 0.05) were present in overweight (BMI 25 to 29.9 kg/m2) and mildly obese (BMI 30 to 35 kg/m2) groups. Differences in RV e(m), s(m), and strain indexes were demonstrated between the severely versus overweight and mildly obese groups (p < 0.05). Body mass index remained independently related to RV changes after adjusting for age, log insulin, and mean arterial pressures. In obese patients, these changes were associated with reduced exercise capacity but not the duration of obesity and presence of sleep apnea or its severity.

CONCLUSIONS

Increasing BMI is associated with increasing severity of RV dysfunction in overweight and obese subjects without overt heart disease, independent of sleep apnea.

Myocardial and vascular dysfunction and exercise capacity in the metabolic syndrome

The metabolic syndrome (MS) is associated with cardiovascular risk exceeding that expected from atherosclerotic risk factors, but the mechanism of this association is unclear. We sought to determine the effects of the MS on myocardial and vascular function and cardiorespiratory fitness in 393 subjects with significant risk factors but no cardiovascular disease and negative stress echocardiographic findings. Myocardial function was assessed by global strain rate, strain, and regional systolic velocity (s(m)) and diastolic velocity (e(m)) using tissue Doppler imaging. Arterial compliance was assessed using the pulse pressure method, involving simultaneous radial applanation tonometry and echocardiographic measurement of stroke volume. Exercise capacity was measured by expired gas analysis. Significant and incremental variations in left ventricular systolic (s(m), global strain, and strain rate) and diastolic (e(m)) function were found according to the number of components of MS (p <0.001). MS contributed to reduced systolic and diastolic function even in those without left ventricular hypertrophy (p <0.01). A similar dose-response association was present between the number of components of the MS and exercise capacity (p <0.001) and arterial compliance. The global strain rate and e(m) were independent predictors of exercise capacity. In conclusion, subclinical left ventricular dysfunction corresponded to the degree of metabolic burden, and these myocardial changes were associated with reduced cardiorespiratory fitness. Subjects with MS who also have subclinical myocardial abnormalities and reduced cardiorespiratory fitness may have a higher risk of cardiovascular disease events and heart failure.

Alterations of left ventricular myocardial characteristics associated with obesity

BACKGROUND

Obesity is associated with heart failure, but an effect of weight, independent of comorbidities, on cardiac structure and function is not well established. We sought whether body mass index (BMI) and insulin levels were associated with subclinical myocardial disturbances.

METHODS AND RESULTS

Transthoracic echocardiography, myocardial Doppler-derived systolic (sm) and early diastolic velocity (em), strain and strain rate imaging and tissue characterization with cyclic variation (CVIB), and calibrated integrated backscatter (cIB) were obtained in 109 overweight or obese subjects and 33 referents (BMI <25 kg/m2). BMI correlated with left ventricular (LV) mass and wall thickness (P<0.001). Severely obese subjects (BMI >35) had reduced LV systolic and diastolic function and increased myocardial reflectivity compared with referents, evidenced by lower average long-axis strain, sm, cIB, lower CVIB, and reduced em, whereas LV ejection fraction remained normal. Differences in regional or global strain, sm, and em were identified between the severely obese (BMI >35) and the referent patients (P<0.001). Similar but lesser degrees of reduced function by sm, em, and basal septal strain and increased reflectivity by cIB were present in overweight (BMI, 25 to 29.9) and mildly obese (BMI, 30 to 35) groups (P<0.05). Although tissue Doppler measures were not associated with duration of obesity, they did correlate with fasting insulin levels and reduced exercise capacity. BMI was independently related to average LV strain (beta=0.40, P=0.02), sm (beta=-0.36, P=0.002), and em (beta=-0.41, P<0.001).

CONCLUSIONS

Overweight subjects without overt heart disease have subclinical changes of LV structure and function even after adjustment for mean arterial pressure, age, gender, and LV mass.

Aging per se does not influence glucose homeostasis: in vivo and in vitro evidence

OBJECTIVE

To assess the effect of age on glucose metabolism by examining 1) glucose metabolism in young and middle-aged subjects when total or regional adiposity is taken into account and 2) in vitro glucose transport in adipose tissue explants from young and middle-aged women paired for total and abdominal adiposity.

RESEARCH DESIGN AND METHODS

Study 1: body composition, subcutaneous abdominal and visceral adipose tissue areas, and fasting and oral glucose-stimulated glucose and insulin were measured in 84 young and 81 middle-aged men and in 110 young and 91 middle-aged women. Study 2: glucose uptake in subcutaneous abdominal and visceral adipose tissue explants were measured in eight young and eight middle-aged women.

RESULTS

Study 1: young and middle-aged men showed similar subcutaneous abdominal tissue area, whereas fat mass and visceral adipose tissue were greater in middle-aged than in young men (P < 0.01). Fat mass and subcutaneous and visceral adipose tissue areas were greater in middle-aged as compared with young women (P < 0.01). Fasting plasma glucose and the glucose response to an oral glucose tolerance test were significantly higher in middle-aged than in young men and women (P < 0.001). Statistical control for visceral adipose tissue area eliminated the difference seen in glucose response in men and women. Study 2: glucose transport in subcutaneous and omental adipose tissue did not differ between young and middle-aged women.

CONCLUSIONS

1) Visceral obesity, more than age per se, correlates with glucose intolerance in middle-aged subjects; 2) aging does not influence in vitro adipose tissue glucose uptake.