Physiology - Research Publications
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ItemNo Preview AvailableThe Impact of Frailty on the Effectiveness and Safety of Intensive Glucose Control and Blood Pressure-Lowering Therapy for People With Type 2 Diabetes: Results From the ADVANCE Trial(AMER DIABETES ASSOC, 2021-07-01)OBJECTIVE: To develop a frailty index (FI) and explore the relationship of frailty to subsequent adverse outcomes on the effectiveness and safety of more intensive control of both blood glucose and blood pressure (BP), among participants with type 2 diabetes in the Action in Diabetes and Vascular Disease: Preterax and Diamicron Modified Release Controlled Evaluation (ADVANCE) trial. RESEARCH DESIGN AND METHODS: Cox proportional hazard models were used to estimate the effectiveness and safety of intensive glucose control and BP intervention according to frailty (defined as FI >0.21) status. The primary outcomes were macro- and microvascular events. The secondary outcomes were all-cause mortality, cardiovascular mortality, severe hypoglycemia, and discontinuation of BP treatment due to hypotension/dizziness. RESULTS: There were 11,140 participants (mean age, 65.8 years; 42.5% women, 25.7% frail). Frailty was an independent predictor of all primary outcomes and secondary outcomes. The effect of intensive glucose treatment on primary outcomes showed some evidence of attenuation in the frail: hazard ratios for combined major macro- and microvascular events 1.03 (95% CI 0.90-1.19) in the frail versus 0.84 (95% CI 0.74-0.94) in the nonfrail (P = 0.02). A similar trend was observed with BP intervention. Severe hypoglycemia rates (per 1,000 person-years) were higher in the frail: 8.39 (6.15-10.63) vs. 4.80 (3.84-5.76) in nonfrail (P < 0.001). There was no significant difference in discontinuation of BP treatment between frailty groups. CONCLUSIONS: It was possible to retrospectively estimate frailty in a trial population, and this FI identified those at higher risk of poor outcomes. Participants with frailty had some attenuation of benefit from intensive glucose-lowering and BP-lowering treatments.
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ItemPolygenic risk scores predict diabetes complications and their response to intensive blood pressure and glucose control(SPRINGER, 2021-07-06)AIMS/HYPOTHESIS: Type 2 diabetes increases the risk of cardiovascular and renal complications, but early risk prediction could lead to timely intervention and better outcomes. Genetic information can be used to enable early detection of risk. METHODS: We developed a multi-polygenic risk score (multiPRS) that combines ten weighted PRSs (10 wPRS) composed of 598 SNPs associated with main risk factors and outcomes of type 2 diabetes, derived from summary statistics data of genome-wide association studies. The 10 wPRS, first principal component of ethnicity, sex, age at onset and diabetes duration were included into one logistic regression model to predict micro- and macrovascular outcomes in 4098 participants in the ADVANCE study and 17,604 individuals with type 2 diabetes in the UK Biobank study. RESULTS: The model showed a similar predictive performance for cardiovascular and renal complications in different cohorts. It identified the top 30% of ADVANCE participants with a mean of 3.1-fold increased risk of major micro- and macrovascular events (p = 6.3 × 10-21 and p = 9.6 × 10-31, respectively) and a 4.4-fold (p = 6.8 × 10-33) higher risk of cardiovascular death. While in ADVANCE overall, combined intensive blood pressure and glucose control decreased cardiovascular death by 24%, the model identified a high-risk group in whom it decreased the mortality rate by 47%, and a low-risk group in whom it had no discernible effect. High-risk individuals had the greatest absolute risk reduction with a number needed to treat of 12 to prevent one cardiovascular death over 5 years. CONCLUSIONS/INTERPRETATION: This novel multiPRS model stratified individuals with type 2 diabetes according to risk of complications and helped to target earlier those who would receive greater benefit from intensive therapy.
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ItemResponse of 1,5-anhydroglucitol level to intensive glucose- and blood-pressure lowering interventions, and its associations with clinical outcomes in the ADVANCE trial(WILEY, 2019-08-01)AIMS: To evaluate 1,5-anhydroglucitol (1,5-AG) according to clinical outcomes and assess the effects of glucose- and blood pressure-lowering interventions on change in 1,5-AG levels in people with type 2 diabetes. METHODS: We measured 1,5-AG in 6826 stored samples at baseline and in a random subsample of 684 participants at the 1-year follow-up visit in the ADVANCE trial. We examined baseline 1,5-AG [< 39.7, 39.7-66.2, ≥ 66.2 μmol/L (<6, 6-10, ≥10 μg/mL)] and microvascular and macrovascular events and mortality using Cox regression models during 5 years of follow-up. Using an intention-to-treat approach, we examined 1-year change in 1,5-AG (mean and percent) in response to the glucose- and blood pressure-lowering interventions in the subsample. RESULTS: Low 1,5-AG level [<39.7 μmol/L vs ≥ 66.2 μmol/L (<6 μg/mL vs ≥10 μg/mL)] was associated with microvascular events (hazard ratio 1.28, 95% confidence interval 1.03-1.60) after adjustment for risk factors and baseline glycated haemoglobin (HbA1c); however, the associations for macrovascular events and mortality were not independent of HbA1c. The glucose-lowering intervention was associated with a significant 1-year increase in 1,5-AG (vs standard control) of 6.69 μmol/L (SE 2.52) [1.01 μg/mL (SE 0.38)], corresponding to an 8.26% (SE 0.10%) increase from baseline. We also observed an increase in 1,5-AG of similar magnitude in response to the blood pressure intervention independent of the glucose-lowering effect. CONCLUSIONS: Our results suggest that 1,5-AG is a marker of risk in adults with type 2 diabetes, but only for microvascular events independently of HbA1c. We found that 1,5-AG was improved (increased) in response to an intensive glucose-lowering intervention, although the independent effect of the blood pressure-lowering intervention on 1,5-AG suggests potential non-glycaemic influences.
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ItemUse of the waist-to-height ratio to predict cardiovascular risk in patients with diabetes: Results from the ADVANCE-ON study(WILEY, 2018-08-01)AIMS: Patients with type 2 diabetes have a high risk of cardiovascular disease (CVD). Central obesity has been particularly associated with this risk relationship. We aimed to evaluate waist to height ratio (WHtR) as a predictor of risk in such patients. METHODS: WHtR was evaluated as a predictor of the risk of CVD and mortality amongst 11 125 participants with type 2 diabetes in the ADVANCE and ADVANCE-ON studies, and was compared with body mass index (BMI), waist circumference and waist hip ratio (WHR). Primary outcome was a composite of death from CVD, non-fatal myocardial infarction or non-fatal stroke. Secondary outcomes were myocardial infarction, stroke, cardiovascular death and death from any cause. Cox models were used, with bootstrapping to compare associations between anthropometric measures for the primary outcome. RESULTS: Median follow-up time was 9.0 years. There was a positive association between WHtR and adverse outcomes. The hazard ratio (HR) (confidence interval), per SD higher WHtR, was 1.16 (1.11-1.22) for the primary endpoint, with no heterogeneity by sex or region, but a stronger effect in individuals aged 66 years or older. The other 3 anthropometric measurements showed similar associations, although there was evidence that WHtR marginally outperformed BMI and WHR. Based on commonly used BMI cut-points, the equivalent WHtR cut-points were estimated to be 0.55 and 0.6, with no evidence of a difference across subgroups. CONCLUSIONS: In patients with diabetes, WHtR is a useful indicator of future adverse risk, with similar effects in different population subgroups.
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ItemNo Preview AvailableSex differences in risk factors for cognitive decline and dementia, including death as a competing risk, in individuals with diabetes: Results from the ADVANCE trial(WILEY, 2021-05-04)AIM: To estimate the associations between risk factors and cognitive decline (CD)/dementia, and the sex differences in these risk factors in individuals with type 2 diabetes, while accounting for the competing risk of death. MATERIALS AND METHODS: The Action in Diabetes and Vascular Disease: Preterax and Diamicron Modified Release Controlled Evaluation (ADVANCE) trial of 11,140 individuals with type 2 diabetes was used to estimate the odds of CD/dementia using multinomial logistic regression. RESULTS: During a median 5-year follow-up, 1827 participants (43.2% women) had CD/dementia (1718 with CD only; 21 with dementia only; 88 with CD and dementia), and 929 (31.0% women) died without CD/dementia. Women had lower odds of CD/dementia than men (odds ratio [OR] [95% confidence interval], 0.88 [0.77, 1.00]); older age, higher total cholesterol, HbA1c, waist circumference, waist-to-height ratio, moderately increased albumin-creatinine ratio, stroke/transient ischaemic attack and retinal disease were each associated with greater odds of CD/dementia; higher years at education completion, baseline cognitive function, taller stature and current alcohol use were inversely associated. Higher waist circumference (women-to-men ratio of ORs [ROR], 1.05 [1.00, 1.10] per 5 cm) and presence of anxiety/depression (ROR, 1.28 [1.01, 1.63]) were associated with greater ORs for CD/dementia in women than men. CONCLUSIONS: Several risk factors were associated with CD/dementia. Higher waist circumference and mental health symptoms were more strongly associated with CD/dementia in women than men. Further studies should examine the mechanisms that underlie these sex differences.
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ItemCardiac mechanical efficiency is preserved in primary cardiac hypertrophy despite impaired mechanical function(ROCKEFELLER UNIV PRESS, 2021-08-02)Increased heart size is a major risk factor for heart failure and premature mortality. Although abnormal heart growth subsequent to hypertension often accompanies disturbances in mechano-energetics and cardiac efficiency, it remains uncertain whether hypertrophy is their primary driver. In this study, we aimed to investigate the direct association between cardiac hypertrophy and cardiac mechano-energetics using isolated left-ventricular trabeculae from a rat model of primary cardiac hypertrophy and its control. We evaluated energy expenditure (heat output) and mechanical performance (force length work production) simultaneously at a range of preloads and afterloads in a microcalorimeter, we determined energy expenditure related to cross-bridge cycling and Ca2+ cycling (activation heat), and we quantified energy efficiency. Rats with cardiac hypertrophy exhibited increased cardiomyocyte length and width. Their trabeculae showed mechanical impairment, evidenced by lower force production, extent and kinetics of shortening, and work output. Lower force was associated with lower energy expenditure related to Ca2+ cycling and to cross-bridge cycling. However, despite these changes, both mechanical and cross-bridge energy efficiency were unchanged. Our results show that cardiac hypertrophy is associated with impaired contractile performance and with preservation of energy efficiency. These findings provide direction for future investigations targeting metabolic and Ca2+ disturbances underlying cardiac mechanical and energetic impairment in primary cardiac hypertrophy.
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ItemNo Preview AvailableSex-specific associations between cardiovascular risk factors and myocardial infarction in patients with type 2 diabetes: TheADVANCE-ONstudy(WILEY, 2020-07-01)AIM: To examine possible sex differences in the excess risk of myocardial infarction (MI) consequent to a range of conventional risk factors in a large-scale international cohort of patients with diabetes, and to quantify these potential differences both on the relative and absolute scales. MATERIALS AND METHODS: Eleven thousand and sixty-five participants (42% women) with type 2 diabetes in the ADVANCE trial and its post-trial follow-up study, ADVANCE-ON, were included. Cox regression models were used to estimate hazard ratios (HRs) for associations between risk factors and MI (fatal and non-fatal) by sex, and the women-to-men ratio of HRs (RHR). RESULTS: Over a median of 9.6 years of follow-up, 719 patients experienced MI. Smoking status, smoking intensity, higher systolic blood pressure (SBP), HbA1c, total and LDL cholesterol, duration of diabetes, triglycerides, body mass index (BMI) and lower HDL cholesterol were associated with an increased risk of MI in both sexes. Furthermore, some variables were associated with a greater relative risk of MI in women than men: RHRs were 1.75 (95% CI: 1.05-2.91) for current smoking, 1.53 (1.00-2.32) for former smoking, 1.18 (1.02-1.37) for SBP, and 1.13 (95% CI, 1.003-1.26) for duration of diabetes. Although incidence rates of MI were higher in men (9.3 per 1000 person-years) compared with women (5.8 per 1000 person-years), rate differences associated with risk factors were greater in women than men, except for HDL cholesterol and BMI. CONCLUSIONS: In patients with type 2 diabetes, smoking, higher SBP and longer duration of diabetes had a greater relative and absolute effect in women than men, highlighting the importance of routine sex-specific approaches and early interventions in women with diabetes.
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ItemNo Preview AvailableGenetic Loci for Retinal Arteriolar Microcirculation(PUBLIC LIBRARY SCIENCE, 2013-06-12)Narrow arterioles in the retina have been shown to predict hypertension as well as other vascular diseases, likely through an increase in the peripheral resistance of the microcirculatory flow. In this study, we performed a genome-wide association study in 18,722 unrelated individuals of European ancestry from the Cohorts for Heart and Aging Research in Genomic Epidemiology consortium and the Blue Mountain Eye Study, to identify genetic determinants associated with variations in retinal arteriolar caliber. Retinal vascular calibers were measured on digitized retinal photographs using a standardized protocol. One variant (rs2194025 on chromosome 5q14 near the myocyte enhancer factor 2C MEF2C gene) was associated with retinal arteriolar caliber in the meta-analysis of the discovery cohorts at genome-wide significance of P-value <5×10(-8). This variant was replicated in an additional 3,939 individuals of European ancestry from the Australian Twins Study and Multi-Ethnic Study of Atherosclerosis (rs2194025, P-value = 2.11×10(-12) in combined meta-analysis of discovery and replication cohorts). In independent studies of modest sample sizes, no significant association was found between this variant and clinical outcomes including coronary artery disease, stroke, myocardial infarction or hypertension. In conclusion, we found one novel loci which underlie genetic variation in microvasculature which may be relevant to vascular disease. The relevance of these findings to clinical outcomes remains to be determined.
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ItemAndrogen Receptor Copy Number Variation and Androgenetic Alopecia: A Case-Control Study(PUBLIC LIBRARY SCIENCE, 2009-04-02)BACKGROUND: The functional polymorphism that explains the established association of the androgen receptor (AR) with androgenetic alopecia (AGA) remains unidentified, but Copy Number Variation (CNV) might be relevant. CNV involves changes in copy number of large segments of DNA, leading to the altered dosage of gene regulators or genes themselves. Two recent reports indicate regions of CNV in and around AR, and these have not been studied in relation to AGA. The aim of this preliminary case-control study was to determine if AR CNV is associated with AGA, with the hypothesis that CNV is the functional AR variant contributing to this condition. METHODOLOGY/PRINCIPAL FINDINGS: Multiplex Ligation-dependent Probe Amplification was used to screen for CNV in five AR exons and a conserved, non-coding region upstream of AR in 85 men carefully selected as cases and controls for maximal phenotypic contrast. There was no evidence of CNV in AR in any of the cases or controls, and thus no evidence of significant association between AGA and AR CNV. CONCLUSIONS/SIGNIFICANCE: The results suggest this form of genomic variation at the AR locus is unlikely to predispose to AGA.
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ItemGenetics of Hypertension and Cardiovascular Disease(HINDAWI LTD, 2010-01-01)