ABSTRACT
Age, hypertension, and the female sex are among the risk factors in the development of heart failure with preserved ejection fraction. We studied by standard and speckle-tracking echocardiography (STE), the response of the left ventricle (LV) to aging and angiotensin II continuous infusion (ANG II; 1.5 mg/kg/day for 28 days) in 2- and 12-mo-old male and female C57Bl6/J mice. We also investigated the effects of the loss of sex steroids by gonadectomy (GDX). To do so, we used STE data from 48 points or regions of interest (ROIs) around the LV endocardium from B-mode images and generated profiles of maximal strain, strain rate (SR), and reverse SR for each experimental group of mice. In young mice, LV strain, strain rate (SR), and reverse SR profile levels were higher in females than in males. Aging was characterized by concentric LV remodeling and a decrease of strain, SR, and reverse SR. GDX at 6 wk of age slowed normal cardiac growth in male mice. In females, GDX reduced LV strain, SR, and reverse SR but did not influence cardiac growth. ANG II caused similar levels of hypertrophy in young and older mice. In young mice, ANG II had little effect on STE parameters, whereas in older animals, strain, SR, and reverse SR were reduced, mainly for the LV posterior wall. In older GDX mice, hypertrophic response to ANG II was decreased compared with intact animals. Generating detailed STE profile for the LV wall can help detect differences linked to sex, age, or a stressor better than global strain measurements.NEW & NOTEWORTHY We propose a new method for the study of regional strain data by analyzing individually the software-generated 48 regions of interest (ROI) from an LV wall tracing in B-mode. This helps obtain a more comprehensive profile of strain data. Using these new tools, we studied in mice how sex, sex hormones, age, or a pathological stress influenced strain parameters. We show that for similar cardiac hypertrophy, regional strain shows important differences related to sex, sex hormones, and age.
Subject(s)
Angiotensin II , Heart Ventricles , Animals , Female , Gonadal Steroid Hormones , Heart Ventricles/diagnostic imaging , Male , Mice , Mice, Inbred C57BL , Steroids , Ventricular Function, Left/physiologyABSTRACT
CONTEXT: Vertebral fracture (VF) prevalence up to 24% has been reported among young people with type 1 diabetes (T1D). If this high prevalence is confirmed, individuals with T1D could benefit from preventative VF screening. OBJECTIVE: We compared the prevalence of VFs between adults with T1D and nondiabetic controls. METHODS: This cross-sectional study included 127 adults with T1D, and 65 controls with a similar age, sex, and BMI distribution, from outpatient clinics of 2 tertiary care centers. Vertebral fracture assessment (VFA) by dual-energy x-ray absorptiometry (DXA) was used for prevalent VFs. The modified algorithm-based qualitative (mABQ) method was applied. Bone mineral density (BMD) and trabecular bone score (TBS) were assessed by DXA. Serum bone turnover markers and sclerostin were measured in a subgroup of participants. RESULTS: Participants with T1D (70 women, 57 men) had a mean age of 42.8â ±â 14.8 years, median diabetes duration of 25.8 (15.8-34.4) years, mean BMI of 26.6â ±â 5.4 kg/m2 and mean HbA1c over the past 3 years of 7.5â ±â 0.9%. Controls (35 women, 30 men) had mean age of 42.2â ±â 15.9 years and mean BMI of 26.1â ±â 5.1 kg/m2. VF prevalence was comparable between groups (2.4% vs 3.1%, Pâ =â 0.99). TBS, BMD at the total hip and femoral neck, and bone formation and resorption markers were lower while sclerostin levels were similar in participants with T1D vs controls. CONCLUSION: Our VFA results using the mABQ method do not confirm increased prevalence of VFs in men and women with relatively well-controlled T1D.
