Age- and sex-dependent changes of resting amygdalar activity in individuals free of clinical cardiovascular disease.

PURPOSE: Amygdalar metabolic activity was shown to independently predict cardiovascular outcomes. However, little is known about age- and sex-dependent variability in neuronal stress responses among individuals free of cardiac disease. This study sought to assess age- and sex-specific differences of resting amygdalar metabolic activity in the absence of clinical cardiovascular disease. METHODS: Amygdalar metabolic activity was assessed in 563 patients who underwent multimodality imaging by 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography and echocardiography for the evaluation of cardiac function. RESULTS: After exclusion of 294 patients with structural or functional cardiovascular pathologies, 269 patients (128 women) remained in the final population. 18F-FDG amygdalar activity significantly decreased with age in men (r = - 0.278, P = 0.001), but not in women (r = 0.002, P = 0.983). Similarly, dichotomous analysis confirmed a lower amygdalar activity in men ≥ 50 years as compared to those < 50 years of age (0.79 ± 0.1 vs. 0.84 ± 0.1, P = 0.007), which was not observed in women (0.81 ± 0.1 vs. 0.82 ± 0.1, P = 0.549). Accordingly, a fully adjusted linear regression analysis identified age as an independent predictor of amygdalar activity only in men (B-coefficient - 0.278, P = 0.001). CONCLUSION: Amygdalar activity decreases with age in men, but not in women. The use of amygdalar activity for cardiovascular risk stratification merits consideration of inherent age- and sex-dependent variability.

Potential Impact of Statins on Neuronal Stress Responses in Patients at Risk for Cardiovascular Disease.

BACKGROUND: Recent studies indicate that enhanced neuronal stress responses are associated with adverse cardiovascular outcomes. A chronic inflammatory state seems to mediate this detrimental neuro-cardiac communication. Statins are among the most widely prescribed medications in primary and secondary cardiovascular disease (CVD) prevention and not only lower lipid levels but also exhibit strong anti-inflammatory and neuroprotective effects. We therefore sought to investigate the influence of statins on neuronal stress responses in a patient cohort at risk for CVD. METHODS: 563 patients (61.5 ± 14.0 years) who underwent echocardiography and 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) were retrospectively identified. Metabolic activity of the amygdala, a part of the brain's salience network, was quantified by 18F-FDG uptake, while normal cardiac morphology and function were assured by echocardiography. Vertebral bone marrow metabolism, a marker of inflammatory activity, was measured by 18F-FDG PET. RESULTS: Increased neuronal stress responses were associated with an increased inflammatory activity in the bone marrow (r = 0.152, p = 0.015) as well as with a subclinical reduction in left ventricular ejection fraction (LVEF, r = -0.138, p = 0.025). In a fully-adjusted linear regression model, statin treatment was identified as an independent, negative predictor of amygdalar metabolic activity (B-coefficient -0.171, p = 0.043). CONCLUSIONS: Our hypothesis-generating investigation suggests a potential link between the anti-inflammatory actions of statins and reduced neuronal stress responses which could lead to improved cardiovascular outcomes. The latter warrants further studies in a larger and prospective population.