Elderly patients with minimal common carotid atherosclerosis not infrequently have severe coronary atherosclerosis and myocardial infarction

Caveolin-1 deletion exacerbates cardiac interstitial fibrosis by promoting M2 macrophage activation in mice after myocardial infarction

Adverse remodeling following myocardial infarction (MI) leading to heart failure is driven by an imbalanced resolution of inflammation. The macrophage cell is an important control of post-MI inflammation, as macrophage subtypes secrete mediators to either promote inflammation and extend injury (M1 phenotype) or suppress inflammation and promote scar formation (M2 phenotype). We have previously shown that the absence of caveolin-1 (Cav1), a membrane scaffolding protein, is associated with adverse cardiac remodeling in mice, but the mechanisms responsible remain to be elucidated. We explore here the role of Cav1 in the activation of macrophages using wild type C57BL6/J (WT) and Cav1(tm1Mls/J) (Cav1(-/-)) mice. By echocardiography, cardiac function was comparable between WT and Cav1(-/-) mice at 3days post-MI. In the absence of Cav1, there were a surprisingly higher percentage of M2 macrophages (arginase-1 positive) detected in the infarcted zone. Conversely, restoring Cav1 function after MI in WT mice by adding back the Cav1 scaffolding domain reduced the M2 activation profile. Further, adoptive transfer of Cav1 null macrophages into WT mice on d3 post-MI exacerbated adverse cardiac remodeling at d14 post-MI. In vitro studies revealed that Cav1 null macrophages had a more pronounced M2 profile activation in response to IL-4 stimulation. In conclusion, Cav1 deletion promotes an array of maladaptive repair processes after MI, including increased TGF-β signaling, increased M2 macrophage infiltration and dysregulation of the M1/M2 balance. Our data also suggest that cardiac remodeling can be improved by therapeutic intervention regulating Cav1 function during the inflammatory response phase.

Mitochondrial haplogroups A and M7a confer a genetic risk for coronary atherosclerosis in the Japanese elderly: an autopsy study of 1,536 patients

AIM

We previously reported significant associations between mitochondrial single nucleotide polymorphisms (mtSNPs) and myocardial infarction, atherothrombotic cerebral infarction, metabolic syndrome and type 2 diabetes. Here, we assessed the hypothesis that mtSNPs may confer a risk for atherosclerosis, the most important intermediate phenotype of ischemic cardiovascular events.

METHODS

The subjects were 1,536 consecutive autopsy cases (827 men and 709 women). The average age at death was 80 years. The severity of coronary atherosclerosis was semi-quantitatively examined on cut sections. We examined 149 mtSNPs using the PCR-Luminex method, with a success rate of 97%. Phylogenetic tree analysis yielded 36 haplogroups. Multiple logistic regression analysis was performed after adjustments for sex, age, and conventional cardiovascular risk factors.

RESULTS

Among the 45 mtSNPs with minor genotype frequencies >0.05, 6 mtSNPs were associated with coronary atherosclerosis. Among 10 haplogroups with frequencies >0.04, haplogroups A and M7a were significantly associated with coronary atherosclerosis, with odds ratios (95% confidence intervals) of 1.80 (1.09-2.97; p=0.023) and 1.92 (1.23-3.01; p=0.004), respectively. Haplogroup D4a, which was previously reported to be associated with extreme longevity in a Japanese population, was associated with pathological myocardial infarction in men with an odds ratio of 2.05 (1.01-4.14; p=0.046).

CONCLUSIONS

The mitochondrial haplogroups A and M7a confer a significant risk for coronary atherosclerosis in the Japanese. The mitochondrial haplogroup may contribute some genetic risk for coronary heart disease.

Effects of phase III cardiac rehabilitation on mortality and cardiovascular events in elderly patients with stable coronary artery disease

BACKGROUND

Cardiac rehabilitation (CR) has numerous benefits, including reduction of mortality and cardiovascular events, in patients with coronary artery disease (CAD). However, the long-term effect of phase III CR in elderly patients with stable CAD is still unknown.

METHODS AND RESULTS

The 111 elderly male CAD patients (>or=65 years), including 37 subjects participating in supervised CR for 6 months and 74 age-matched controls, were analyzed. The patients were followed for up to 3,500 days, until the occurrence of death or 1 of the following major adverse cardiovascular events (MACE): cardiovascular death, acute coronary syndrome, refractory angina requiring revascularization, admission for congestive heart failure, or stroke. All-cause mortality tended to be lower in the CR group than in the Control group (14% vs 28%, P=0.081). The MACE incidence was significantly lower in the CR group than in the Control group (30% vs 62%, P=0.001). Multivariate Cox proportional hazard analysis showed that the MACE incidence was significantly lower in the CR group than in the Control group [adjusted hazard ratio 0.43 (95% confidence interval 0.20-0.91), P=0.027].

CONCLUSIONS

Phase III CR has the beneficial effect of reducing cardiovascular events even in elderly patients with stable CAD.