Reliability of the hyperaemic response to passive leg movement in young, healthy women.

NEW FINDINGS: What is the central question of this study? This is the first study to assess the day-to-day reliability of passive leg movement-induced hyperaemia (PLM-H), an index of lower-limb microvascular function, in young, healthy women. What is the main finding and its importance? Passive leg movement-induced hyperaemia demonstrated good day-to-day reliability, comparable to other common indices of endothelial function, supporting the use of PLM-H to assess lower-limb microvascular function in women. ABSTRACT: Passive leg movement-elicited hyperaemia (PLM-H) provides an index of lower-limb microvascular function. However, there is currently limited information regarding the reliability of PLM-H and no reliability information specific to women. The purpose of this study was to determine the reliability of PLM-H in women on two separate days. Seventeen young, healthy women [22 ± 3 years old (mean ± SD)] participated in two identical visits including three trials of PLM. Using duplex ultrasound, PLM-H was characterized by six indices: peak leg blood flow (LBF) and vascular conductance (LVC), peak change above baseline (Δpeak) for LBF and LVC, and area under the curve above baseline (AUC) during the first 60 s of PLM for LBF and LVC. The results demonstrated good day-to-day reliability of PLM-H characterized as peak LBF [r = 0.84, P < 0.001; intraclass correlation coefficient (ICC) = 0.84; coefficient of variation (CV) = 13.2%], peak LVC (r = 0.82, P < 0.001; ICC = 0.79; CV = 14.4%), Δpeak LBF (r = 0.83, P < 0.001; ICC = 0.82; CV = 17.8%) and Δpeak LVC (r = 0.83, P < 0.001; ICC = 0.80; CV = 16.5%). Characterization of PLM as AUC demonstrated moderate day-to-day reliability: AUC LBF (r = 0.71, P < 0.05; ICC = 0.70; CV = 31.2%) and AUC LVC (r = 0.78, P < 0.001; ICC = 0.74; CV = 27.1%). In conclusion, this study demonstrates that PLM-H has good reliability as an index of microvascular function; however, characterization of PLM-H as peak, Δpeak LBF and LVC is more reliable than AUC.

Individual variation of follicular phase changes in endothelial function across two menstrual cycles.

NEW FINDINGS: What is the central question of this study? The purpose of this study was to determine intra-individual reproducibility of follicular phase changes in endothelial function (flow-mediated dilatation) over two menstrual cycles in healthy, premenopausal women. What is the main finding and its importance? Phase changes in endothelial function were not consistent at the individual level across two menstrual cycles, which challenges the utility of interpreting individual responses over one cycle. ABSTRACT: Evidence regarding the impact of menstrual phase on endothelial function is conflicting, and studies to date have examined responses only over a single cycle. It is unknown whether the observed inter-individual variability of phase changes in endothelial function reflects stable, inter-individual differences in responses to oestrogen (E2 ; a primary female sex hormone). The purpose of this study was to examine changes in endothelial function from the early follicular (EF; low-E2 ) phase to the late follicular (LF; high-E2 ) phase over two consecutive cycles. Fourteen healthy, regularly menstruating women [22 ± 3 years of age (mean ± SD)] participated in four visits (EFVisit 1 , LFVisit 2 , EFVisit 3 and LFVisit 4 ) over two cycles. Ovulation testing was used to determine the time between the LF visit and ovulation. During each visit, endothelial function [brachial artery flow-mediated dilatation (FMD)], E2 and progesterone were assessed. At the group level, there was no impact of phase or cycle on FMD (P = 0.48 and P = 0.65, respectively). The phase change in FMD in cycle 1 did not predict the phase change in cycle 2 (r = 0.03, P = 0.92). Using threshold-based classification (2 × typical error threshold), four of 14 participants (29%) exhibited directionally consistent phase changes in FMD across cycles. Oestrogen was not correlated between cycles, and this might have contributed to variability in the FMD response. The intra-individual variability in follicular fluctuation in FMD between menstrual cycles challenges the utility of interpreting individual responses to phase over a single menstrual cycle.

MicroRNAs as biomarkers for monitoring cardiovascular changes in Type II Diabetes Mellitus (T2DM) and exercise.

Introduction: MicroRNAs (miRNAs) have been shown to be altered in both CVD and T2DM and can have an application as diagnostic and prognostic biomarkers. miRNAs are released into circulation when the cardiomyocyte is subjected to injury and damage. Objectives: Measuring circulating miRNA levels in human plasma may be of great potential use for measuring the extent of damage to cardiomyocytes and response to exercise. This review is aimed to highlight the potential application of miRNAs as biomarkers of CVD progression in T2DM, and the impact of exercise on recovery. Methods: The review aims to examine whether the health improvements following exercise in T2DM patients are reflective of changes in expression of plasma miRNAs. For this purpose, studies were identified from the literature that have established a correlation between diabetes, disease progression and plasma miRNA levels. We also reviewed studies which looked at the effect of exercise on plasma miRNA levels. Results: The review identified miRNA signatures that are affected by T2DM and DHD and a subset of these miRNAs that are also affected by different types of exercise. This approach helped us to identify those miRNAs whose expression and function can be altered by regular bouts of exercise. Conclusions: miRNAs identified as part of this review can serve as tools to monitor the cardio-protective, anti-inflammatory and metabolic effects of exercise in people suffering from T2DM. Future research should focus on regulation of these miRNAs in T2DM and how they can be altered by appropriate exercise interventions. Supplementary Information: The online version contains supplementary material available at 10.1007/s40200-022-01066-4.