Current and emerging drug targets in heart failure treatment

After initial strategies targeting inotropism and congestion, the neurohormonal interpretative model of heart failure (HF) pathophysiology has set the basis for current pharmacological management of HF, as most of guideline recommended drug classes, including beta-blockers, angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, and mineralocorticoid receptor antagonists, blunt the activation of detrimental neurohormonal axes, namely sympathetic and renin–angiotensin–aldosterone (RAAS) systems. More recently, sacubitril/valsartan, a first-in-class angiotensin receptor neprilysin inhibitor, combining inhibition of RAAS and potentiation of the counter-regulatory natriuretic peptide system, has been consistently demonstrated to reduce mortality and HF-related hospitalization. A number of novel pharmacological approaches have been tested during the latest years, leading to mixed results. Among them, drugs acting directly at a second messenger level, such as the soluble guanylate cyclase stimulator vericiguat, or other addressing myocardial energetics and mitochondrial function, such as elamipretide or omecamtiv-mecarbil, will likely change the therapeutic management of patients with HF. Sodium glucose cotransporter 2 inhibitors, initially designed for the management of type 2 diabetes mellitus, have been recently demonstrated to improve outcome in HF, although mechanisms of their action on cardiovascular system are yet to be elucidated. Most of these emerging approaches have shifted the therapeutic target from neurohormonal systems to the heart, by improving cardiac contractility, metabolism, fibrosis, inflammation, and remodeling. In the present paper, we review from a pathophysiological perspective current and novel therapeutic strategies in chronic HF.

Synergistic effect of cranberry extract and losartan against aluminium chloride-induced hepatorenal damage associated cardiomyopathy in rats

The present study was designed to evaluate the effect of cranberry extract (CRAN) and/or losartan (LOS) against aluminium chloride (AlCl₃) induced hepatorenal damage associated cardiomyopathy in rats. To induce hepatorenal and cardiotoxicity, animals were received (AlCl₃; 70 mg/kg i.p.) for 8 weeks day after day and treated with CRAN (100 mg/kg b.wt.) orally daily for 4 weeks started after 4 weeks from AlCl₃ injection accompanied with an administration of LOS (5 mg/kg i.p.) three times weekly for 4 weeks. Our data revealed that, compared to AlCl₃, administration of CRAN extract and LOS produced a significant improvement which was evidenced by a significant amelioration in myocardial and vascular indices, kidney and liver markers, lipid profile and oxidative stress indices. Furthermore, histopathological and immunohistochemical examination reinforced the previous results. It could be concluded that combination of CRAN extract and LOS hindered AlCl₃ induced hepatorenal damage complicated cardiomyopathy in rats.

Association of CVD candidate gene polymorphisms with ischemic stroke and cerebral hemorrhage in Chinese individuals

BACKGROUND

Contribution of cardiovascular disease related genetic risk factors for stroke are not clearly defined. We performed a genetic association study to assess the association of 56 previously characterized gene variants in 34 candidate genes from cardiovascular disease related biological pathways with ischemic stroke and cerebral hemorrhage in a Chinese population.

METHODS

There were 1280 stroke patients (1101 with ischemic stroke and 179 with cerebral hemorrhage) and 1380 controls in the study. The genotypes for 56 polymorphisms of 34 candidate genes were determined by the immobilized probe approach and the associations of gene polymorphisms with ischemic stroke and cerebral hemorrhage were performed by logistic regression under an allelic model.

RESULTS

After adjusting for age, sex, BMI and hypertension status by logistic regression analysis, we found that NPPA rs5063 was significantly associated with both ischemic stroke (odds ratio [OR] 0.69; 95% confidence interval [CI], 0.52 to 0.90; P = 0.006) and cerebral hemorrhage(OR = 0.39; 95%CI, 0.19 to 0.78; P = 0.007). In addition, MTHFR rs1801133 also was associated with cerebral hemorrhage (OR = 1.48; 95%CI, 1.16 to 1.89; P = 0.001) but not with ischemic stroke (OR = 1.08; 95%CI, 0.96 to 1.22; P = 0.210). After false discovery rate (FDR) correction, the association of NPPA rs5063 and MTHFR rs1801133 with cerebral hemorrhage remained significant.

CONCLUSIONS

The NPPA rs5063 is associated with reduced risk for cerebral hemorrhage and MTHFR rs1801133 is associated with increased risk of cerebral hemorrhage in a Chinese population.

Atrial natriuretic peptide gene delivery reduces stroke-induced mortality rate in Dahl salt-sensitive rats

Atrial natriuretic peptide (ANP) is a powerful hormone with hypotensive, natriuretic, diuretic, and many other beneficial effects. Direct infusion of ANP in therapeutics has limited success because of its short half-life in the circulation. Our previous studies have shown that ANP gene delivery attenuates hypertension, cardiac hypertrophy, and renal injury in Dahl salt-sensitive (Dahl-SS) rats. To investigate the potential therapeutic value of ANP gene delivery on salt-induced stroke and cerebrovascular disorders, an adenovirus harboring the human ANP gene (Ad.RSV-cANP) was injected into Dahl-SS rats on a high salt diet. A single intravenous injection of the ANP gene caused a significant reduction of blood pressure that lasted for more than 3 weeks. A maximal blood pressure reduction of 28 mm Hg was observed 2 weeks after gene delivery as compared with that of control rats injected with adenovirus harboring the LacZ gene under the control of the Rous sarcoma virus promoter (Ad.RSV-LacZ). Immunoreactive human ANP can be detected in the heart, lung, kidney, and brain of rats after gene delivery. The stroke mortality rate of Dahl-SS rats was significantly decreased (from 54% to 17% at 3 weeks and from 70% to 50% at 4 weeks after ANP gene delivery as compared with rats injected with control virus). ANP gene delivery also significantly attenuates salt-induced aortic hypertrophy as evidenced by reduced thickness of the aortic wall. This is the first study to demonstrate the potential of ANP gene delivery in reducing the mortality rate caused by cerebrovascular disorders and stroke. Successful application of this technology may have potential value in treating individuals with a high risk of stroke.

Human atrial natriuretic peptide gene delivery reduces blood pressure in hypertensive rats

Chronic infusion of atrial natriuretic peptide (ANP) has been shown to cause natriuresis, diuresis, and hypotension in rats and humans. We explored the effect of a continuous supply of ANP by somatic ANP delivery on genetically hypertensive rats. A DNA construct containing the human ANP gene fused to the Rous sarcoma virus 3'-long terminal repeat (RSV-LTR) was injected intravenously into spontaneously hypertensive rats (SHR) through the tail vein. Expression of human ANP in SHR was identified in the heart, lung, and kidney by radioimmunoassay and reverse transcription-polymerase chain reaction followed by Southern blot analysis. A single injection of naked ANP plasmid DNA (12.3 kb) caused a significant reduction of systemic blood pressure in young SHR (4 weeks old), and the effect continued for 7 weeks. The differences were significant at 1 to 2 weeks (n = 6, P < .05) and 3 to 6 weeks after injection (n = 6, P < .01) A maximal blood pressure reduction of 21 mm Hg in young SHR was observed 5 weeks after injection with ANP DNA (159.4 +/- 3.02 mm Hg, mean +/- SEM, n = 6) compared with SHR injected with vector DNA alone (180.2 +/- 3.02 mm Hg, mean +/- SEM; n = 6; P < .01). Somatic gene delivery of human ANP DNA had no effect on the blood pressure of adult SHR (12 weeks old). After ANP gene delivery, there were significant increases in urinary volume and urinary potassium output (n = 6, P < .05) but not in body weight, heart rate, water intake, urinary sodium output, urinary creatine, and urinary protein.(ABSTRACT TRUNCATED AT 250 WORDS)

Atrial natriuretic factor and transgenic mice

Atrial natriuretic factor (ANF) is a peptide hormone that induces potent but transient hypotensive and natriuretic responses on short-term administration. The role of the hormone in long-term cardiovascular regulation has remained elusive in part because of the temporal limitations of long-term infusion models and the extremely short half-life of the molecule in vivo. To circumvent these temporal limitations, a transgenic mouse model was developed that exhibits lifelong elevated plasma ANF levels. These mice are chronically hypotensive, with arterial pressures averaging 20 to 30 mm Hg less than those observed in nontransgenic siblings. In contrast, no obvious natriuretic or diuretic phenotype was observed in transgenic animals housed in metabolic cages. Thus, the mice adequately compensate for the renal effects but not the hemodynamic effects of the hormone. The ANF transgenic mice provide a tractable model system with which to study the consequences of long-term alterations of ANF expression in vivo.

Nitric oxide is a mediator of hypoxic coronary vasodilatation. Relation to adenosine and cyclooxygenase-derived metabolites

Hypoxia is a potent coronary-vasodilating signal; its mechanisms are still controversial. We have assessed the possible role of nitric oxide (NO) in hypoxic coronary vasodilatation (HCVD) in isolated guinea pig hearts perfused at constant pressure. HCVD was elicited by a 1-minute 100% N2 exposure; coronary flow doubled within 1 minute of hypoxia (early phase) and returned to baseline within 40 seconds after reoxygenation (late phase). The early phase of HCVD was associated with a rapid approximately eightfold increase in cGMP overflow, an indication of NO release. The specific NO synthase inhibitor N omega-methyl-L-arginine (NMA, 0.1-1 mM) antagonized HCVD and the associated increase in cGMP spillover (maximum inhibition, approximately 65%); excess arginine (1.2 mM) prevented both effects. The late phase of HCVD was associated with an increase in adenosine overflow and was attenuated by the adenosine receptor antagonist BW A1433 (1 microM; maximum inhibition, approximately 45%). Indomethacin (10 microM) inhibited HCVD in spontaneously beating hearts by approximately 35% but had no effect in hearts paced at faster rates. NMA and BW A1433 were more effective in combination than alone (maximum inhibition, approximately 72%). However, irrespective of the concentrations used, there was no synergism among the anti-HCVD effects of NMA, BW A1433, and indomethacin, nor was HCVD completely inhibited by the antagonists, whether alone or in combination. Our findings indicate that NO is an important mediator of the early phase of HCVD, whereas additional mechanisms and/or factors, including adenosine and vasodilatatory prostaglandins, contribute to the late phase.