Tadalafil treatment improves cardiac, renal and lower urinary tract dysfunctions in rats with heart failure

Tadalafil Use in Cardiovascular Disease

Tadalafil is a phosphodiesterase inhibitor currently approved for use in erectile dysfunction (ED), benign prostatic hyperplasia (BPH), and pulmonary arterial hypertension (PAH). While tadalafil's benefits in ED and BPH have been well-established for years, its benefits in PAH were identified only recently in major clinical trials, resulting in the recent approval of a single-tablet, combination therapy of tadalafil with an endothelin receptor antagonist for PAH. With Tadalafil's cardiovascular benefits in ED, BPH, and PAH, clinical researchers have begun investigating whether tadalafil's use extends to other cardiovascular diseases, especially heart failure (HF), an emerging epidemic in medicine. Recent research in animal models has demonstrated a potential benefit of tadalafil use in ischemic cardiomyopathy and HF, as numerous studies in mice and sheep demonstrated improved left ventricular function and contractility, with reduced adverse remodeling and hypertrophy. A retrospective cohort study identified that tadalafil use in patients with ED and coronary artery disease was associated with a significant decrease in the incidence of HF, acute myocardial infarction, and mortality compared with sildenafil or no treatment. However, a randomized controlled trial in patients with comorbid PAH and HF with preserved ejection fraction demonstrated no significant benefit with the use of tadalafil. Unfortunately, there is limited evidence from clinical trials investigating the impact of tadalafil in patients with HF with reduced or preserved ejection fraction without comorbid PAH. Further studies are needed on this topic to better identify whether tadalafil has a role in the prevention or treatment of HF.

Research progress of indole-fused derivatives as allosteric modulators: Opportunities for drug development

Allosteric modulation is a direct and effective method for regulating the function of biological macromolecules, which play vital roles in various cellular activities. Unlike orthosteric modulators, allosteric modulators bind to sites distant from the protein's orthosteric/active site and can have specific effects on the protein's function or activity without competing with endogenous ligands. Compared to traditional orthosteric modulators, allosteric modulators offer several advantages, including reduced side effects, greater specificity, and lower toxicity, making them a promising strategy for developing novel drugs. Indole-fused architectures are widely distributed in natural products and bioactive drug leads, displaying diverse biological activities that attract the interest of both chemists and biologists in drug discovery. Currently, an increasing number of indole-fused compounds have exhibited potent activities in allosteric modulation. In this review, we provide a brief summary of examples of allosteric modulators based on the indole-fused complex architecture, highlighting the strategies for drug design/discovery and the structure-activity relationships of allosteric modulators from the perspective of medicinal chemistry.