Introduction: There are a number of structural and functional changes in the heart with aging and each of them can have significant implications for manifestation of cardiovascular disease (CVD). Assessment of myocardial strain by using the new techniques such as speckle-tracking echocardiography (STE) could become a more sensitive analysis of the cardiac aging. One possible mechanism of the aging heart can be associated with formation glucose-dependent cross-links of collagen, termed advanced glycation end products (AGEs). AGEs accumulate with age, and can increased myocardial stiffness and changes in the biomechanics of contraction. These age-related changes can be associated with shortening of telomeres – a marker of replicative senescence. The purpose of this study was to examine the left ventricular (LV) myocardial strain in relation with glycation and telomere shortening.
Methods: 2-D speckle tracking analysis was performed on 151 healthy non-obese volunteers aged 60 to 87 years without history of CVD, diabetes and significant deviations by 12-lead electrocardiogram. LV myocardial deformations were obtained using off-line analysis program QLAB.Global longitudinal LV strain (GLS), LV systolic twist, circumferential and radial strains were measured. Methylglyoxal (MG) is a byproduct of glucose metabolism and an inducer of AGEs. Concentration of MG in serum was determined using HPLC with UV detector. Telomere length was measured in leukocyte (LTL) by real-time quantitative polymerase chain reaction.
Results: The subjects were 66.05±7.07 years old, 42% were men. GLS was reduced in older people (-16.36±1.26%), radial strain of LV basal (42.95±5.06%) and LV systolic twist (8.76±1.56°) were increased. Age was related to GLS (β=0.120, p=0.01), radial strain (β=0.202, p=0.01) and LV systolic twist (β=0.225, p=0.003). Changes of myocardial deformations were observed in 80% of the people in the absence of diastolic dysfunction. LTL was associated with age (β=-0.026, p=0.015), LV systolic twist (r=-0.761, p=0.03) and GLS (r=0.507, p=0.002). MG was related with age (r=0.866, p<0.001), but not related with LTL (p>0.05). In multivariate regression MG was associated with GLS (β=-0.128, p=0.005) and LV twist (β=0.518, p=0.03). Increased MG was observed in 91% of elderly patients with increased LV twist and in 88% with reduced GLS. Older subjects with higher MG and shorter telomeres length had more pronounced changes in the biomechanics of myocardial contraction.
Conclusions: Our findings suggest that myocardial strain evaluated by using STE is more sensitive markers of cardiac aging than standard echocardiography parameters. Accumulation AGEs associated with reduce of GLS and increase of LV systolic twist, significant contributing factors in heart aging. Changes in these parameters of STE are related to shortening of telomere length.