Clinically Administered Doses of Pitavastatin and Rosuvastatin

Clinical studies have indicated that 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors, also known as statins, can potentially inhibit chronic heart failure. In the Stat-LVDF study, a difference was noted in terms of the effect of lipophilic pitavastatin (PTV) and hydrophilic rosuvastatin (RSV) on plasma BNP, suggesting that statin lipophilicity and pharmacokinetics change the pleiotropic effect on heart failure in humans. Therefore, we assessed the beneficial effects of PTV on hypertrophy in cardiac myocytes compared with RSV at clinically used doses. Cultured cardiomyocytes were stimulated with 30 μM phenylephrine (PE) in the presence of PTV (250 nM) or RSV (50 nM). These doses were calculated based on the maximum blood concentration of statins used in clinical situations in Japan. The results showed that PTV, but not RSV, significantly inhibits the PE-induced increase in cell size and leucine incorporation without causing cell toxicity. In addition, PTV significantly suppressed PE-induced mRNA expression of hypertrophic response genes. PE-induced ERK phosphorylation was inhibited by PTV, but not by RSV. Furthermore, PTV significantly suppressed the angiotensin-II-induced proline incorporation in primary cultured cardiac fibroblasts. In conclusion, a clinical dose of PTV was noted to directly inhibit cardiomyocyte hypertrophy and cardiac fibrosis, suggesting that lipophilic PTV can be a potential drug candidate against chronic heart failure.

Cardiac and renal protective effects of 2,5-dimethylcelecoxib in angiotensin II and high-salt-induced hypertension model mice

BACKGROUND

We reported that 2,5-dimethylcelecoxib (DM-celecoxib), a celecoxib derivative that is unable to inhibit cyclooxygenase-2, prevented cardiac remodeling induced by sarcomeric gene mutation, left ventricular pressure overload, or β-adrenergic receptor stimulation. This effect seemed to be mediated by the inhibition of the canonical Wnt/β-catenin signaling pathway, which has been suggested to play a key role in the development of chronic kidney disease and chronic heart failure.

METHOD

We investigated the effect of DM-celecoxib on cardiac remodeling and kidney injury in hypertension model mice induced by angiotensin II infusion in the absence or presence of high-salt load.

RESULTS

DM-celecoxib prevented cardiac remodeling and markedly reduced urinary albumin excretion without altering blood pressure in those mice. Moreover, DM-celecoxib prevented podocyte injury, glomerulosclerosis, and interstitial fibrosis in the kidney of mice loaded with angiotensin II and high-salt load. DM-celecoxib reduced the phosphorylation level of Akt and activated glycogen synthase kinase-3, which led to the suppression of the Wnt/β-catenin signal in the heart and kidney. DM-celecoxib also reduced the expression level of snail, a key transcription factor for the epithelial-mesenchymal transition and of which gene is a target of the Wnt/β-catenin signal.

CONCLUSION

Results of the current study suggested that DM-celecoxib could be beneficial for patients with hypertensive heart and kidney diseases.

A peptide vaccine targeting angiotensin II attenuates the cardiac dysfunction induced by myocardial infarction

A peptide vaccine targeting angiotensin II (Ang II) was recently developed as a novel treatment for hypertension to resolve the problem of noncompliance with pharmacotherapy. Ang II plays a crucial role in the pathogenesis of cardiac remodeling after myocardial infarction (MI), which causes heart failure. In the present study, we examined whether the Ang II vaccine is effective in preventing heart failure. The injection of the Ang II vaccine in a rat model of MI attenuated cardiac dysfunction in association with an elevation in the serum anti-Ang II antibody titer. Furthermore, any detrimental effects of the Ang II vaccine were not observed in the rats that underwent sham operations. Treatment with immunized serum from Ang II vaccine-injected rats significantly suppressed post-MI cardiac dysfunction in MI rats and Ang II-induced remodeling-associated signaling in cardiac fibroblasts. Thus, our present study demonstrates that the Ang II vaccine may provide a promising novel therapeutic strategy for preventing heart failure.

Regulation of microvascularization in heart failure - an endothelial cell, non-coding RNAs and exosome liaison

Heart failure is a complex syndrome involving various pathophysiological processes. An increasing body of evidence shows that the myocardial microvasculature is essential for the homeostasis state and that a decompensated heart is associated with microvascular dysfunction as a result of impaired endothelial angiogenic capacity. The intercellular communication between endothelial cells and cardiomyocytes through various signaling molecules, such as vascular endothelial growth factor, nitric oxide, and non-coding RNAs is an important determinant of cardiac microvascular function. Non-coding RNAs are transported from endothelial cells to cardiomyocytes, and vice versa, regulating microvascular properties and angiogenic processes in the heart. Small-exocytosed vesicles, called exosomes, which are secreted by both cell types, can mediate this intercellular communication. The purpose of this review is to highlight the contribution of the microvasculature to proper heart function maintenance by focusing on the interaction between cardiac endothelial cells and myocytes with a specific emphasis on non-coding RNAs (ncRNAs) in this form of cell-to-cell communication. Finally, the potential of ncRNAs as targets for angiogenesis therapy will also be discussed.

2,5-Dimethylcelecoxib prevents pressure-induced left ventricular remodeling through GSK-3 activation

Glycogen synthase kinase-3 (GSK-3) is a crucial regulator of cardiac hypertrophy. We previously reported that 2,5-dimethylcelecoxib (DM-celecoxib), a celecoxib derivative unable to inhibit cyclooxygenase-2, prevented cardiac remodeling by activating GSK-3, resulting in lifespan prolongation in a mouse model of genetic dilated cardiomyopathy. In the present study, we investigated whether DM-celecoxib can also prevent pressure-induced cardiac remodeling and heart failure, elicited by transverse aortic constriction (TAC). Before testing the effects of DM-celecoxib, we compared the effects of TAC on the hearts of wild-type and GSK-3β hetero-deficient (GSK-3β^+/-) mice to determine the role of GSK-3 in cardiac remodeling and heart failure. GSK-3β^+/- mouse hearts exhibited more severe hypertrophy, which was characterized by accelerated interstitial fibrosis, than wild-type mouse hearts after TAC, suggesting that reduced GSK-3β activity aggravates pressure-induced left ventricular remodeling. We subsequently examined the effects of DM-celecoxib on TAC-induced cardiac remodeling. DM-celecoxib inhibited left ventricular systolic functional deterioration, and prevented left ventricular hypertrophy and fibrosis. It also activated GSK-3α and β by inhibiting Akt, suppressing the activity of β-catenin and nuclear factor of activated T-cells and thereby decreasing the expression of the Wnt/β-catenin target gene products fibronectin and matrix metalloproteinase-2. These results suggest that DM-celecoxib is clinically useful for treating pressure-induced heart diseases.

Aldehyde dehydrogenase 2 deficiency blunts compensatory cardiac hypertrophy through modulating Akt phosphorylation early after transverse aorta constriction in mice

AIMS

This study was designed to examine the impact of mitochondrial aldehyde dehydrogenase 2 (ALDH2) on transverse aorta constriction (TAC)-induced cardiac hypertrophy and related molecular mechanisms using an ALDH2 knockout (ALDH2-/-) murine model.

METHODS

Male wild-type and ALDH2-/- mice were subjected to TAC or sham operation (n=6-8 for each group). After two weeks, cardiac function was assessed by echocardiography and hemodynamic measurements. Myocardial phosphorylated and total PI3K, the catalytic subunit of PI3Ks (p110α and p110γ), Akt, and total PTEN levels were detected by Western blotting. Cardiomyocytes were stretched for 6h in vitro in the presence or absence of Alda-1 (a small-molecule activator of ALDH2) prior to assessment of phosphorylated PI3K, Akt and total PTEN expressions by Western blot.

RESULTS

Heart to body weight ratio and left ventricular posterior wall thickness as well as the cross-sectional area of cardiomyocyte were significantly lower in ALDH2-/- mice than in wild-type mice following TAC. Western blot analysis showed p110γ was upregulated post TAC in both wild-type mice and ALDH2-/- mice, phosphorylation of Akt was disrupted, PTEN expression was upregulated in ALDH2-/- mice post TAC while phosphorylated PI3K, p110α and p110γ expression was similar between ALDH2-/- and wild-type mice post TAC. In vitro, phosphorylation of Akt was significantly accentuated and PTEN expression was reduced while PI3K phosphorylation remained unchanged in stretched cardiomyocytes pretreated by Alda-1 compared to stretched cardiomyocytes treated by saline.

CONCLUSIONS

Our results show that ALDH2 deficiency attenuates compensatory cardiac hypertrophy through regulating Akt but not PI3K phosphorylation early after TAC in mice.

SmgGDS as a Crucial Mediator of the Inhibitory Effects of Statins on Cardiac Hypertrophy and Fibrosis: Novel Mechanism of the Pleiotropic Effects of Statins

The detailed molecular mechanisms of the pleiotropic effects of statins remain to be fully elucidated. Here, we hypothesized that cardioprotective effects of statins are mediated by small GTP-binding protein GDP dissociation stimulator (SmgGDS). SmgGDS(+/-) and wild-type (WT) mice were treated with continuous infusion of angiotensin II (Ang II) for 2 weeks with and without oral treatment with atorvastatin or pravastatin. At 2 weeks, the extents of Ang II-induced cardiac hypertrophy and fibrosis were comparable between the 2 genotypes. However, statins significantly attenuated cardiomyocyte hypertrophy and fibrosis in WT mice, but not in SmgGDS(+/-) mice. In SmgGDS(+/-) cardiac fibroblasts (CFs), Rac1 expression, extracellular signal-regulated kinases 1/2 activity, Rho-kinase activity, and inflammatory cytokines secretion in response to Ang II were significantly increased when compared with WT CFs. Atorvastatin significantly reduced Rac1 expression and oxidative stress in WT CFs, but not in SmgGDS(+/-) CFs. Furthermore, Bio-plex analysis revealed significant upregulations of inflammatory cytokines/chemokines and growth factors in SmgGDS(+/-) CFs when compared with WT CFs. Importantly, conditioned medium from SmgGDS(+/-) CFs increased B-type natriuretic peptide expression in rat cardiomyocytes to a greater extent than that from WT CFs. Furthermore, atorvastatin significantly increased SmgGDS secretion from mouse CFs. Finally, treatment with recombinant SmgGDS significantly reduced Rac1 expression in SmgGDS(+/-) CFs. These results indicate that both intracellular and extracellular SmgGDS play crucial roles in the inhibitory effects of statins on cardiac hypertrophy and fibrosis, partly through inhibition of Rac1, Rho kinase, and extracellular signal-regulated kinase 1/2 pathways, demonstrating the novel mechanism of the pleiotropic effects of statins.

Angiogenesis and cardiac hypertrophy: maintenance of cardiac function and causative roles in heart failure

Cardiac hypertrophy is an adaptive response to physiological and pathological overload. In response to the overload, individual cardiac myocytes become mechanically stretched and activate intracellular hypertrophic signaling pathways to re-use embryonic transcription factors and to increase the synthesis of various proteins, such as structural and contractile proteins. These hypertrophic responses increase oxygen demand and promote myocardial angiogenesis to dissolve the hypoxic situation and to maintain cardiac contractile function; thus, these responses suggest crosstalk between cardiac myocytes and microvasculature. However, sustained pathological overload induces maladaptation and cardiac remodeling, resulting in heart failure. In recent years, specific understanding has increased with regard to the molecular processes and cell-cell interactions that coordinate myocardial growth and angiogenesis. In this review, we summarize recent advances in understanding the regulatory mechanisms of coordinated myocardial growth and angiogenesis in the pathophysiology of cardiac hypertrophy and heart failure.

Effects of pitavastatin on cardiac structure and function and on prevention of atrial fibrillation in elderly hypertensive patients: a prospective study of 2-years' follow-up

BACKGROUND

The aim of this prospective study was to determine whether statin therapy (pitavastatin) has a beneficial effect on the prevention of new-onset atrial fibrillation (AF) in elderly patients with hypertension (HTN) and to evaluate the relationships among statin treatment, the development of AF, and left atrial (LA) and ventricular (LV) structure and function.

METHODS AND RESULTS

We enrolled eligible elderly patients (≥65 years old) with HTN and LV hypertrophy until the number of patients reached 110 in both groups. The 110 patients with HTN who needed statin therapy (HTN with statin group) were started on pitavastatin (1-2 mg/day), and both groups continued with appropriate medication for HTN. LV and LA structure and function were examined by conventional and speckle-tracking echocardiography at baseline and after 1 year. LA volume and function in the HTN with statin group improved more than in the HTN without statin group. There was a significant difference in survival free of new-onset AF in the patients with and without statin therapy during the 2-year follow-up (hazard ratio: 0.32, P=0.027).

CONCLUSIONS

Pitavastatin had a beneficial effect on LV diastolic function and LA structure and function in elderly patients with HTN. Pitavastatin treatment may be associated with a lower incidence of new-onset AF.