The metabolic syndrome (MetS) confers an increased risk for diabetes and cardiovascular disease. Although high-sensitive C-reactive protein (hsCRP) concentrations are higher and adiponectin concentrations lower in MetS, there is no reliable biochemical measure that can capture its various features. We evaluated whether hsCRP, adiponectin, or the ratio of adiponectin or its oligomers, especially the high-molecular-weight (HMW) oligomer, to hsCRP predict MetS in 123 subjects with MetS compared with that in 91 healthy control subjects. MetS subjects had significantly higher hsCRP levels and lower total adiponectin and oligomer levels relative to control subjects (P < .0001). The HMW/total adiponectin and adiponectin/CRP ratios were significantly lower in MetS subjects than control subjects (P < .005). The odds ratio (OR) of MetS using the 75th percentile cutoff for CRP was 3.8 (95% confidence interval [CI], 2.1-6.8) and equivalent to low total adiponectin (OR, 2.5; 95% CI, 1.3-4.5), its oligomers, or the adiponectin/ hsCRP ratio (OR, 2.6; 95% CI, 1.5, 4.8). Thus, measurements of CRP, adiponectin, or its oligomers provide robust biomarkers for predicting MetS.

Background

Poor fitness in middle age is a risk factor for heart failure, particularly heart failure with a preserved ejection fraction. The development of heart failure with a preserved ejection fraction is likely mediated through increased left ventricular (LV) stiffness, a consequence of sedentary aging. In a prospective, parallel group, randomized controlled trial, we examined the effect of 2 years of supervised high-intensity exercise training on LV stiffness.

Methods

Sixty-one (48% male) healthy, sedentary, middle-aged participants (53±5 years) were randomly assigned to either 2 years of exercise training (n=34) or attention control (control; n=27). Right heart catheterization and 3-dimensional echocardiography were performed with preload manipulations to define LV end-diastolic pressure-volume relationships and Frank-Starling curves. LV stiffness was calculated by curve fit of the diastolic pressure-volume curve. Maximal oxygen uptake (Vo₂max) was measured to quantify changes in fitness.

Results

Fifty-three participants completed the study. Adherence to prescribed exercise sessions was 88±11%. Vo₂max increased by 18% (exercise training: pre 29.0±4.8 to post 34.4±6.4; control: pre 29.5±5.3 to post 28.7±5.4, group×time P<0.001) and LV stiffness was reduced (right/downward shift in the end-diastolic pressure-volume relationships; preexercise training stiffness constant 0.072±0.037 to postexercise training 0.051±0.0268, P=0.0018), whereas there was no change in controls (group×time P<0.001; pre stiffness constant 0.0635±0.026 to post 0.062±0.031, P=0.83). Exercise increased LV end-diastolic volume (group×time P<0.001), whereas pulmonary capillary wedge pressure was unchanged, providing greater stroke volume for any given filling pressure (loading×group×time P=0.007).

Conclusions

In previously sedentary healthy middle-aged adults, 2 years of exercise training improved maximal oxygen uptake and decreased cardiac stiffness. Regular exercise training may provide protection against the future risk of heart failure with a preserved ejection fraction by preventing the increase in cardiac stiffness attributable to sedentary aging.

Clinical trial registration

URL: https://www.clinicaltrials.gov. Unique identifier: NCT02039154.