Age-related differences in skeletal muscle microvascular response to exercise as detected by contrast-enhanced ultrasound (CEUS)

Abstract

BackgroundAging involves reductions in exercise total limb blood flow and exercise capacity. We hypothesized that this may involve early age-related impairments of skeletal muscle microvascular responsiveness as previously reported for insulin but not for exercise stimuli in humans.MethodsUsing an isometric exercise model, we studied the effect of age on contrast-enhanced ultrasound (CEUS) parameters, i.e. microvascular blood volume (MBV), flow velocity (MFV) and blood flow (MBF) calculated from replenishment of Sonovue contrast-agent microbubbles after their destruction. CEUS was applied to the vastus lateralis (VLat) and intermedius (VInt) muscle in 15 middle-aged (MA, 43.6±1.5 years) and 11 young (YG, 24.1±0.6 years) healthy males before, during, and after 2 min of isometric knee extension at 15% of peak torque (PT). In addition, total leg blood flow as recorded by femoral artery Doppler-flow. Moreover, fiber-type-specific and overall capillarisation as well as fiber composition were additionally assessed in Vlat biopsies obtained from CEUS site. MA and YG had similar quadriceps muscle MRT-volume or PT and maximal oxygen uptake as well as a normal cardiovascular risk factors and intima-media-thickness.ResultsDuring isometric exercise MA compared to YG reached significantly lower levels in MFV (0.123±0.016 vs. 0.208±0.036 a.u.) and MBF (0.007±0.001 vs. 0.012±0.002 a.u.). In the VInt the (post-occlusive hyperemia) post-exercise peaks in MBV and MBF were significantly lower in MA vs. YG. Capillary density, capillary fiber contacts and femoral artery Doppler were similar between MA and YG.ConclusionsIn the absence of significant age-related reductions in capillarisation, total leg blood flow or muscle mass, healthy middle-aged males reveal impaired skeletal muscle microcirculatory responses to isometric exercise. Whether this limits isometric muscle performance remains to be assessed.

The Role of Muscle Perfusion in the Age-Associated Decline of Mitochondrial Function in Healthy Individuals

“…Although there is compelling evidence from respirometry conducted in permeabilized human muscle fibers that mitochondrial function intrinsically declines with age (Short et al, 2005; Mellem et al, 2017), we cannot exclude the possibility that changes in muscle perfusion also play an important role in the age-associated decline of mitochondrial function and ultimately whole-body aerobic capacity. For example, it has been suggested that age (Lawrenson et al, 2004; Hearon and Dinenno, 2016; Hildebrandt et al, 2017) and disease (Gueugneau et al, 2016; Wagenmakers et al, 2016; Creager, 2018) may impair the transport of oxygen and nutrients because of a reduction in cardiac function or impairment of peripheral vascular adaptation. Indeed, a wealth of data suggest that both capillary density (Urbieta-Caceres et al, 2012; Barnouin et al, 2017) and vasodilation that occurs under metabolic demand substantially decrease in older adults (Mueller et al, 2017; Tonson et al, 2017).…”

Contrast‐Enhanced Ultrasound (CEUS) as Predictor for Early Retear and Functional Outcome After Supraspinatus Tendon Repair

“…Contrast‐enhanced ultrasound (CEUS) allows for a dynamic quantification of perfusion in muscle tissue. Being closely linked to the responsiveness and recruitment of muscle fibers and the muscle metabolism, CEUS has been suggested as functional real‐time biomarker for muscle vitality and function beyond morphologic aspects . Originally implemented for assistive diagnostics of liver and kidney tumors in 2004, CEUS has nowadays been translated into the clinical routine of numerous pathologies and was lately evaluated for various musculoskeletal indications, including shoulder pathologies .…”

Effects of Physiotherapy Interventions on the Function of the Locomotor System in Elder Age: View of Theory and Practice

“…A new promising tool is the contrast-enhanced ultrasound (CEUS) method that provides a relatively non-invasive imaging technique for clinical and research application [29]. By using this technique, impaired micro-vascular reaction to isometric exercise and attenuated, delayed post-exercise hyperemia were found in middle-aged subjects in comparison to young people without significant differences in vascular morphology and total leg perfusion [30].…”