Dilated cardiomyopathy is a major cause of heart failure that affects millions. Corin cleaves and biologically activates pro-atrial natriuretic peptide (pro-ANP) and pro-B-type natriuretic peptide (pro-BNP). High corin levels reduce the development of systolic dysfunction and heart failure in experimental dilated cardiomyopathy. Yet, patients with significant heart failure unexpectedly show low corin levels with high plasma ANP/BNP levels. Therefore, we examined the relationship between cardiac corin expression, ANP/BNP levels and the stages of heart failure. We used a well-established, dilated cardiomyopathy model to evaluate gene and protein expression as mice longitudinally developed Stages A-D heart failure. Cardiac systolic function (ejection fraction) continuously declined over time (P<0.001). Cardiac corin transcripts were decreased at early Stage B heart failure and remained low through Stages C-D (P<0.001). Cardiac corin levels were positively correlated with systolic function (r=0.96, P=0.003) and inversely with lung water (r=-0.92, P=0.001). In contrast, cardiac pro-ANP/BNP transcripts increased later (Stage C-D) and plasma levels rose only with terminal heart failure (Stage D, P<0.001). Immunoreactive plasma ANP and BNP levels were positively associated with plasma cyclic guanosine monophosphate (cGMP) levels (r=0.82, P=0.01 & r=0.8, P=0.02 respectively). In experimental dilated cardiomyopathy, corin levels declined early with progressive systolic dysfunction before the development of heart failure, while significant increases in plasma ANP, BNP and cGMP levels were found only in later Stage (C, D) heart failure. This dyssynchrony in expression of corin vs. ANP/BNP may impair cleavage-activation of pro-natriuretic peptides and thereby promote the transition from earlier to later stage heart failure.

Dilated cardiomyopathy (DCM) is the major cause of heart failure affecting both women and men. Limited clinical studies show conflicting data in sex-related differences in the progression of dilated cardiomyopathy and heart failure (HF) outcomes. We examined the comparative sex-related progression of cardiomyopathy and the development of HF (at 4, 7, 13 weeks of age) in a well-established, transgenic mouse model of DCM that recapitulates the progressive stages of human HF. By 13 weeks of age, female mice with DCM had more severe left ventricular systolic dysfunction, left ventricular dilation and wall thinning (P<0.001 for all) than age-matched male mice with DCM. Female mice also had greater lung edema (P<0.001), cardiac fibrosis (P<0.01) and pleural effusions, which were not rescued by ovariectomy. By comparison to DCM male mice at 13 weeks, these pathological changes in female mice with DCM, were associated with significant increases in plasma active renin (P<0.01), angiotensin II (P<0.01) and aldosterone levels (P<0.001). In comparison to DCM male mice, DCM female mice also showed differential expression of the natriuretic peptide system with lower corin and higher ANP, BNP and cGMP levels at 13 weeks of age. We conclude, that female mice with experimental DCM have an accelerated progression of cardiomyopathy and HF, which was not corrected by early ovariectomy. These alterations are associated with early renin activation with increased angiotensin II and aldosterone levels, and altered expression of the natriuretic peptide system.

Dilated cardiomyopathy is a frequent cause of heart failure and death. Atrial natriuretic peptide (ANP) is a biomarker of dilated cardiomyopathy, but there is controversy whether ANP modulates the development of heart failure. Therefore we examined whether ANP affects heart failure, cardiac remodeling, function and survival in a well-characterized, transgenic model of dilated cardiomyopathy. Mice with dilated cardiomyopathy with normal ANP levels survived longer than mice with partial ANP (p<0.01) or full ANP deficiency (p<0.001). In dilated cardiomyopathy mice, ANP protected against the development of heart failure as indicated by reduced lung water, alveolar congestion, pleural effusions etc. ANP improved systolic function and reduced cardiomegaly. Pathologic cardiac remodeling was diminished in mice with normal ANP as indicated by decreased ventricular interstitial and perivascular fibrosis. Mice with dilated cardiomyopathy and normal ANP levels had better systolic function (p<0.001) than mice with dilated cardiomyopathy and ANP-deficiency. Dilated cardiomyopathy was associated with diminished cardiac transcripts for natriuretic peptide receptors A and B in mice with normal ANP and ANP-deficiency but transcripts for natriuretic peptide receptor C and CNP were selectively altered in mice with dilated cardiomyopathy and ANP-deficiency. Taken together, these data indicate that ANP has potent effects in experimental dilated cardiomyopathy that reduce the development of heart failure, prevent pathologic remodeling, preserve systolic function and reduce mortality. Despite the apparent overlap in physiologic function between the natriuretic peptides, these data suggest that the role of ANP in dilated cardiomyopathy and heart failure is not compensated physiologically by other natriuretic peptides.

Prenatal alcohol exposure often results in fetal alcohol syndrome and fetal alcohol spectrum disorders. Mechanisms of fetal brain damage by alcohol remain unclear. We used baboons (Papio spp.) to study alcohol-driven changes in the fetal cerebral artery endocannabinoid system. Pregnant baboons were subjected to binge alcohol exposure via gastric infusion three times during a period equivalent to the second trimester of human pregnancy. A control group was infused with orange-flavored drink that was isocaloric to the alcohol-containing solution. Cesarean sections were performed at a time equivalent to the end of the second trimester of human pregnancy. Fetal cerebral arteries were harvested and subjected to in vitro pressurization followed by pharmacological profiling. During each alcohol-infusion episode, maternal blood alcohol concentrations (BAC) reached 80 mg/dL, that is, equivalent to the BAC considered legal intoxication in humans. Circulating anandamide (AEA) and 2-arachidonoylglycerol (2-AG) remained unchanged. Ultrasound studies on pregnant mothers revealed that fetal alcohol exposure decreased peak systolic blood velocity in middle cerebral arteries when compared to pre-alcohol levels. Moreover, ethanol-induced dilation was observed in fetal cerebral arteries pressurized in vitro. This dilation was abolished by the mixture of AM251 and AM630, which block cannabinoid receptors 1 and 2, respectively. In the presence of AM251, the cannabinoid receptor agonist AEA evoked a higher, concentration-dependent dilation of cerebral arteries from alcohol-exposed fetuses. The difference in AEA-induced cerebral artery dilation vanished in the presence of AM630. CB1 and CB2 receptor mRNA and protein levels were similar in cerebral arteries from alcohol-exposed and control-exposed fetuses. In summary, alcohol exposure dilates fetal cerebral arteries via endocannabinoid receptors and results in an increased function of CB2.

Heart failure (HF) patients frequently have elevated plasma renin activity. We examined the significance of elevated plasma renin activity in a translationally-relevant model of dilated cardiomyopathy (DCM), which replicates the progressive stages (A–D) of human HF. Female mice with DCM and elevated plasma renin activity concentrations were treated with a direct renin inhibitor (aliskiren) in a randomized, blinded fashion beginning at Stage B HF. By comparison to controls, aliskiren treatment normalized pathologically elevated plasma renin activity (p < 0.001) and neprilysin levels (p < 0.001), but did not significantly alter pathological changes in plasma aldosterone, angiotensin II, atrial natriuretic peptide, or corin levels. Aliskiren improved cardiac systolic function (ejection fraction, p < 0.05; cardiac output, p < 0.01) and significantly reduced the longitudinal development of edema (extracellular water, p < 0.0001), retarding the transition from Stage B to Stage C HF. The normalization of elevated plasma renin activity reduced the loss of body fat and lean mass (cachexia/sarcopenia), p < 0.001) and prolonged survival (p < 0.05). In summary, the normalization of plasma renin activity retards the progression of experimental HF by improving cardiac systolic function, reducing the development of systemic edema, cachexia/sarcopenia, and mortality. These data suggest that targeting pathologically elevated plasma renin activity may be beneficial in appropriately selected HF patients.