The gender differences in the relaxation to levosimendan of human internal mammary artery

Understanding the Clinical Use of Levosimendan and Perspectives on its Future in Oncology

Drug repurposing, also known as repositioning or reprofiling, has emerged as a promising strategy to accelerate drug discovery and development. This approach involves identifying new medical indications for existing approved drugs, harnessing the extensive knowledge of their bioavailability, pharmacokinetics, safety and efficacy. Levosimendan, a calcium sensitizer initially approved for heart failure, has been repurposed for oncology due to its multifaceted pharmacodynamics, including phosphodiesterase 3 inhibition, nitric oxide production and reduction of reactive oxygen species. Studies have demonstrated that levosimendan inhibits cancer cell migration and sensitizes hypoxic cells to radiation. Moreover, it exerts organ-protective effects by activating mitochondrial potassium channels. Combining levosimendan with traditional anticancer agents such as 5-fluorouracil (5-FU) has shown a synergistic effect in bladder cancer cells, highlighting its potential as a novel therapeutic approach. This drug repurposing strategy offers a cost-effective and time-efficient solution for developing new treatments, ultimately contributing to the advancement of cancer therapeutics and improved outcomes for patients. Further investigations and clinical trials are warranted to validate the effectiveness of levosimendan in oncology and explore its potential benefits in a clinical setting.

Levosimendan-induced venodilation is mediated by opening of potassium channels

Unique vascular responses adhere to the cardiovascular efficacy of the inodilator levosimendan. In particular, selective venodilation appears to explain its clinical benefit during pulmonary hypertension complicated by heart failure with preserved ejection fraction. Vasodilators increase vessel diameter in various parts of the vascular system to different degrees and thereby influence blood pressure, its distribution, and organ perfusion depending on their mechanisms of action. Levosimendan and its long‐lived active metabolite OR‐1896 mobilize a set of vasodilatory mechanisms, that is, the opening of the ATP‐sensitive K⁺ channels and other K⁺ channels on top of a highly selective inhibition of the phosphodiesterase III enzyme. A vessel‐specific combination of the above vasodilator mechanisms—in concert with cardiac effects and cardiovascular reflex regulations—illustrates the pharmacological profile of levosimendan in various cardiovascular disorders. While levosimendan has been known to be an inotrope, its properties as an activator of ATP‐sensitive K⁺ channels have gone largely ignored with respect to clinical applications. Here, we provide a summary of what is known about the ATP‐sensitive K⁺ channel properties in preclinical studies and now for the first time, its ATP‐sensitive K⁺ channel properties in a clinical trial.

Effects of levosimendan on isolated human internal mammary artery and saphenous vein: concurrent use with conventional vasodilators

Graft spasm is a common problem in coronary artery bypass grafting (CABG). In this study, we aimed to investigate the interaction of levosimendan, a novel inodilator, with vasodilator agents that are clinically used for the treatment of graft spasm and with endogenous vasoconstrictors that are thought to play a role in graft vasospasm, in human internal mammary artery (IMA) and saphenous vein (SV). Isolated human IMA and SV segments derived from patients undergoing CABG were suspended in an organ bath. Responses to cumulative concentrations of noradrenaline (NA), serotonin (5-HT), papaverine, nitroglycerin (NG), and diltiazem were recorded before and after 10(-5) m levosimendan incubation (30 min). In addition, cumulative levosimendan responses were taken in vessels precontracted with NA or 5-HT. 10(-5) m levosimendan reduced NA Emax and sensitivity in IMA and SV, and 5-HT Emax responses in IMA. Moreover, levosimendan caused concentration-dependent relaxation in both grafts. Papaverine Emax or sensitivity was not altered by levosimendan neither in IMA nor in SV. Levosimendan diminished NG sensitivity in IMA and Emax responses in SV and decreased diltiazem Emax responses both in IMA and SV. Our results suggest that levosimendan may be used alone for prevention or treatment of graft spasm in IMA or in combination with papaverine in IMA and SV grafts. However, as concurrent administration with diltiazem or NG causes a reduction in relaxation in vitro, we suggest caution should be exercised when using levosimendan in combination with these agents.

Age-dependent sex effects on outcomes after pediatric cardiac surgery

BACKGROUND

Sex has been linked to differential outcomes for cardiovascular disease in adults. We examined potential sex differences in outcomes after pediatric cardiac surgery.

METHODS AND RESULTS

We retrospectively analyzed data from the Pediatric Cardiac Care Consortium (1982-2007) by using logistic regression to evaluate the effects of sex on 30-day within-hospital mortality after pediatric (<18 years old) cardiac operations and its interaction with age, risk category, z-score for weight, and surgical year for the whole cohort. Of 76 312 operations, 55% were in boys. Unadjusted mortality was similar for boys and girls (5.2% versus 5.0%, P=0.313), but boys were more likely to have cardiac surgery as a neonate and to have more complex operations. After adjustment, the overall test of any association between postsurgical mortality and sex was significant (P=0.002), but the overall test of any interaction was not (P=0.503). However, a potential age-dependent sex effect on postsurgical mortality was observed among infants subjected to high-risk operations, with girls doing worse during the first 6 months of life.

CONCLUSIONS

Patient sex has a significant effect on mortality after pediatric cardiac operations, with an increased risk of death in early infancy for girls after high-risk cardiac operations. This age-dependent relationship supports a sex-related biological effect on postoperative cardiovascular stress.

Levosimendan induces NO production through p38 MAPK, ERK and Akt in porcine coronary endothelial cells: role for mitochondrial K(ATP) channel

BACKGROUND AND PURPOSE

Levosimendan acts as a vasodilator through the opening of ATP-sensitive K(+) channels (K(ATP)) channels. Moreover, the coronary vasodilatation caused by levosimendan in anaesthetized pigs has recently been found to be abolished by the nitric oxide synthase (NOS) inhibitor N(omega)-nitro-L-arginine methyl ester, indicating that nitric oxide (NO) has a role in the vascular effects of levosimendan. However, the intracellular pathway leading to NO production caused by levosimendan has not yet been investigated. Thus, the purpose of the present study was to examine the effects of levosimendan on NO production and to evaluate the intracellular signalling pathway involved.

EXPERIMENTAL APPROACH

In porcine coronary endothelial cells (CEC), the release of NO in response to levosimendan was examined in the presence and absence of N(omega)-nitro-L-arginine methyl ester, an adenylyl cyclase inhibitor, K(ATP) channel agonists and antagonists, and inhibitors of intracellular protein kinases. In addition, the role of Akt, ERK, p38 and eNOS was investigated through Western blot analysis.

KEY RESULTS

Levosimendan caused a concentration-dependent and K(+)-related increase of NO production. This effect was amplified by the mitochondrial K(ATP) channel agonist, but not by the selective plasma membrane K(ATP) channel agonist. The response of CEC to levosimendan was prevented by the K(ATP) channel blockers, the adenylyl cyclase inhibitor and the Akt, ERK, p38 inhibitors. Western blot analysis showed that phosphorylation of the above kinases lead to eNOS activation.

CONCLUSIONS AND IMPLICATIONS

In CEC levosimendan induced eNOS-dependent NO production through Akt, ERK and p38. This intracellular pathway is associated with the opening of mitochondrial K(ATP) channels and involves cAMP.

Sex and age dimorphism of myocardial gene expression in nonischemic human heart failure

BACKGROUND

We report the first comprehensive analysis of gene expression differences by sex and age in left ventricular samples from 102 patients with dilated cardiomyopathy.

METHODS AND RESULTS

Gene expression data (HG-U133A gene chip, Affymetrix) were analyzed from 30 females and 72 males from 3 separate centers. More than 1800 genes displayed sexual dimorphism in the heart (adjusted P value <0.05). A significant number of these genes were highly represented in gene ontology pathways involved in ion transport and G-protein-coupled receptor signaling. Localization of these genes revealed enrichment on both the sex chromosomes as well as chromosomes 3, 4, and 14. The second goal of this study was to determine the effect of age on gene expression. Within the female cohort, >140 genes were differentially expressed in the <55 years age group compared with the >55 years age group. These genes were highly represented in gene ontology pathways involved in DNA damage. In contrast, zero genes in the male cohort <55 years met statistical significance when compared with the >55 years age group.

CONCLUSIONS

Gene expression in dilated cardiomyopathy displayed evidence of sexual dimorphism similar to other somatic tissues and age dimorphism within the female cohort.