Repurposing of medications for pulmonary arterial hypertension

Pulmonary hypertension and the potential of 'drug' repurposing: A case for African medicinal plants

Abstract

Pulmonary hypertension (PH) is a haemodynamic disorder in which elevated blood pressure in the pulmonary circulation is caused by abnormal vascular tone. Despite advances in treatment, PH mortality remains high, and drug repurposing has been proposed as a mitigating approach. This article reviews the studies that have investigated drug repurposing as a viable option for PH. We provide an overview of PH and highlight pharmaceutical drugs with repurposing potential, based on limited evidence of their mechanisms of action. Moreover, studies have demonstrated the benefits of medicinal plants in PH, most of which are of Indian or Asian origin. Africa is a rich source of many medicinal plants that have been scientifically proven to counteract myriad pathologies. When perusing these studies, one will notice that some African medicinal plants can counteract the molecular pathways (e.g. proliferation, vasoconstriction, inflammation, oxidative stress and mitochondrial dysfunction) that are also involved in the pathogenesis of PH. We review the actions of these plants with actions applicable to PH and highlight that they could be repurposed as adjunct PH therapies. However, these plants have either never been tested in PH, or there is little evidence of their actions against PH. We therefore encourage caution, as more research is needed to study these plants further in experimental models of PH while acknowledging that the outcomes of such proof of-concept studies may not always yield promising findings. Regardless, this article aims to stimulate future research that could make timely contributions to the field.

Study synopsis

What the study adds. Pulmonary hypertension (PH) remains a fatal disease, and 80% of the patients live in developing countries where resources are scarce and specialised therapies are often unavailable. Drug repurposing is a viable option to try to improve treatment outcomes.Implications of the findings. We propose that another form of 'drug' repurposing is the use of medicinal plants, many of which have demonstrated benefits against pathological processes that are also key in PH, e.g. apoptosis, tumour-like growth of cells, proliferation, oxidative stress and mitochondrial dysfunction.

Mast Cells in Cardiac Remodeling: Focus on the Right Ventricle

In response to various stressors, cardiac chambers undergo structural remodeling. Long-term exposure of the right ventricle (RV) to pressure or volume overload leads to its maladaptive remodeling, associated with RV failure and increased mortality. While left ventricular adverse remodeling is well understood and therapeutic options are available or emerging, RV remodeling remains underexplored, and no specific therapies are currently available. Accumulating evidence implicates the role of mast cells in RV remodeling. Mast cells produce and release numerous inflammatory mediators, growth factors and proteases that can adversely affect cardiac cells, thus contributing to cardiac remodeling. Recent experimental findings suggest that mast cells might represent a potential therapeutic target. This review examines the role of mast cells in cardiac remodeling, with a specific focus on RV remodeling, and explores the potential efficacy of therapeutic interventions targeting mast cells to mitigate adverse RV remodeling.

Pulmonary arterial hypertension nanotherapeutics: New pharmacological targets and drug delivery strategies

Pulmonary arterial hypertension (PAH) is a rare, serious, and incurable disease characterized by high lung pressure. PAH-approved drugs based on conventional pathways are still not exhibiting favorable therapeutic outcomes. Drawbacks like short half-lives, toxicity, and teratogenicity hamper effectiveness, clinical conventionality, and long-term safety. Hence, approaches like repurposing drugs targeting various and new pharmacological cascades and/or loaded in non-toxic/efficient nanocarrier systems are being investigated lately. This review summarizes the status of conventional, repurposed, either in vitro, in vivo, and/or in clinical trials of PAH treatment. In-depth description, discussion, and classification of the new pharmacological targets and nanomedicine strategies with a description of all the nanocarriers that showed promising efficiency in delivering drugs are discussed. Ultimately, an illustration of the different nucleic acids tailored and nanoencapsulated within different types of nanocarriers to restore the pathways affected by this disease is presented.

Medical Management of Pulmonary Arterial Hypertension: Current Approaches and Investigational Drugs

Pulmonary arterial hypertension (PAH) is a malignant pulmonary vascular syndrome characterized by a progressive increase in pulmonary vascular resistance and pulmonary arterial pressure, which eventually leads to right heart failure and even death. Although the exact mechanism of PAH is not fully understood, pulmonary vasoconstriction, vascular remodeling, immune and inflammatory responses, and thrombosis are thought to be involved in the development and progression of PAH. In the era of non-targeted agents, PAH had a very dismal prognosis with a median survival time of only 2.8 years. With the deep understanding of the pathophysiological mechanism of PAH as well as advances in drug research, PAH-specific therapeutic drugs have developed rapidly in the past 30 years, but they primarily focus on the three classical signaling pathways, namely the endothelin pathway, nitric oxide pathway, and prostacyclin pathway. These drugs dramatically improved pulmonary hemodynamics, cardiac function, exercise tolerance, quality of life, and prognosis in PAH patients, but could only reduce pulmonary arterial pressure and right ventricular afterload to a limited extent. Current targeted agents delay the progression of PAH but cannot fundamentally reverse pulmonary vascular remodeling. Through unremitting efforts, new therapeutic drugs such as sotatercept have emerged, injecting new vitality into this field. This review comprehensively summarizes the general treatments for PAH, including inotropes and vasopressors, diuretics, anticoagulants, general vasodilators, and anemia management. Additionally, this review elaborates the pharmacological properties and recent research progress of twelve specific drugs targeting three classical signaling pathways, as well as dual-, sequential triple-, and initial triple-therapy strategies based on the aforementioned targeted agents. More crucially, the search for novel therapeutic targets for PAH has never stopped, with great progress in recent years, and this review outlines the potential PAH therapeutic agents currently in the exploratory stage to provide new directions for the treatment of PAH and improve the long-term prognosis of PAH patients.

Fabrication of Novel Omeprazole-Based Chitosan Coated Nanoemulgel Formulation for Potential Anti-Microbia; In Vitro and Ex Vivo Characterizations

Infectious diseases remain inevitable factors for high mortality and morbidity rate in the modern world to date. Repurposing is a novel approach to drug development has become an intriguing research topic in the literature. Omeprazole is one of the top ten proton pump inhibitors prescribed in the USA. The literature suggests that no reports based on omeprazole anti-microbial actions have been discovered to date. This study entails the potential of omeprazole to treat skin and soft tissue infections based on the literature's evident anti-microbial effects. To get a skin-friendly formulation, a chitosan-coated omeprazole-loaded nanoemulgel formulation was fabricated using olive oil, carbopol 940, Tween 80, Span 80, and triethanolamine by high-speed homogenization technique. The optimized formulation was physicochemically characterized for zeta potential, size distribution, pH, drug content, entrapment efficiency, viscosity, spreadability, extrudability, in-vitro drug release, ex-vivo permeation analysis, and minimum inhibitory concentration determination. The FTIR analysis indicated that there was no incompatibility between the drug and formulation excipients. The optimized formulation exhibited particle size, PDI, zeta potential, drug content, and entrapment efficiency of 369.7 ± 8.77 nm, 0.316, -15.3 ± 6.7 mV, 90.92 ± 1.37% and 78.23 ± 3.76%, respectively. In-vitro release and ex-vivo permeation data of optimized formulation showed 82.16% and 72.21 ± 1.71 μg/cm², respectively. The results of minimum inhibitory concentration (1.25 mg/mL) against selected bacterial strains were satisfactory, suggesting a successful treatment approach for the topical application of omeprazole to treat microbial infections. Furthermore, chitosan coating synergistically increases the antibacterial activity of the drug.

Therapeutic targeting of mineralocorticoid receptors in pulmonary hypertension: Insights from basic research

Pulmonary hypertension (PH) is characterized by pulmonary vascular remodeling and associated with adverse outcomes. In patients with PH, plasma aldosterone levels are elevated, suggesting that aldosterone and its receptor, the mineralocorticoid receptor (MR), play an important role in the pathophysiology of PH. The MR plays a crucial role in adverse cardiac remodeling in left heart failure. A series of experimental studies from the past few years indicate that MR activation promotes adverse cellular processes that lead to pulmonary vascular remodeling, including endothelial cell apoptosis, smooth muscle cell (SMC) proliferation, pulmonary vascular fibrosis, and inflammation. Accordingly, in vivo studies have demonstrated that pharmacological inhibition or cell-specific deletion of the MR can prevent disease progression and partially reverse established PH phenotypes. In this review, we summarize recent advances in MR signaling in pulmonary vascular remodeling based on preclinical research and discuss the potential, but also the challenges, in bringing MR antagonists (MRAs) into clinical application.

Identifying key transcription factors and miRNAs coregulatory networks associated with immune infiltrations and drug interactions in idiopathic pulmonary arterial hypertension

BACKGROUND

The deregulated genetic factors are critically associated with idiopathic pulmonary arterial hypertension (IPAH) development and progression. However, the identification of hub-transcription factors (TFs) and miRNA-hub-TFs co-regulatory network-mediated pathogenesis in IPAH remains lacking.

METHODS

We used GSE48149, GSE113439, GSE117261, GSE33463, and GSE67597 for identifying key genes and miRNAs in IPAH. We used a series of bioinformatics approaches, including R packages, protein-protein interaction (PPI) network, and gene set enrichment analysis (GSEA) to identify the hub-TFs and miRNA-hub-TFs co-regulatory networks in IPAH. Also, we employed a molecular docking approach to evaluate the potential protein-drug interactions.

RESULTS

We found that 14 TFs encoding genes, including ZNF83, STAT1, NFE2L3, and SMARCA2 are upregulated, and 47 TFs encoding genes, including NCOR2, FOXA2, NFE2, and IRF5 are downregulated in IPAH relative to the control. Then, we identified the differentially expressed 22 hub-TFs encoding genes, including four upregulated (STAT1, OPTN, STAT4, and SMARCA2) and 18 downregulated (such as NCOR2, IRF5, IRF2, MAFB, MAFG, and MAF) TFs encoding genes in IPAH. The deregulated hub-TFs regulate the immune system, cellular transcriptional signaling, and cell cycle regulatory pathways. Moreover, the identified differentially expressed miRNAs (DEmiRs) are involved in the co-regulatory network with hub-TFs. The six hub-TFs encoding genes, including STAT1, MAF, CEBPB, MAFB, NCOR2, and MAFG are consistently differentially expressed in the peripheral blood mononuclear cells of IPAH patients, and these hub-TFs showed significant diagnostic efficacy in distinguishing IPAH cases from the healthy individuals. Moreover, we revealed that the co-regulatory hub-TFs encoding genes are correlated with the infiltrations of various immune signatures, including CD4 regulatory T cells, immature B cells, macrophages, MDSCs, monocytes, Tfh cells, and Th1 cells. Finally, we discovered that the protein product of STAT1 and NCOR2 interacts with several drugs with appropriate binding affinity.

CONCLUSIONS

The identification of hub-TFs and miRNA-hub-TFs co-regulatory networks may provide a new avenue into the mechanism of IPAH development and pathogenesis.

Experience with and perceptions of non-prescription anthelmintics for cancer treatments among cancer patients in South Korea: A cross-sectional survey

Although non-prescription anthelmintics are used by many patients as cancer treatment in South Korea, data regarding the experiences or perceptions of these drugs are lacking. This study aimed to investigate the repercussions of non-prescription anthelmintics for cancer treatment and evaluate their perceived effectiveness and adverse effects. This survey included 86 cancer patients, aged 19 years and older, who underwent anthelmintic therapy for cancer. They were recruited from two online communities in South Korea through a structured questionnaire that was provided online. Cancer patients under non-prescription anthelmintic therapy for cancer in South Korea were mostly in their advanced stages and had started the treatment in 2019. About half of the cancer patients had taken non-prescription anthelmintics during their chemotherapy, and 96.5% of them did not inform the clinicians. These participants had a positive perception (79.1%) toward the effectiveness of anthelmintics, as they felt it improved their physical condition. Data on the adverse effects of anthelmintics showed that more than two-third of the participants did not report experiencing any adverse effects. Communication between the clinicians and cancer patients regarding the use of non-prescription anthelmintics should be enhanced to prevent adverse effects.

TRPC6, a therapeutic target for pulmonary hypertension

Idiopathic pulmonary arterial hypertension (PAH) is a fatal and progressive disease. Sustained vasoconstriction due to pulmonary arterial smooth muscle cell (PASMC) contraction and concentric arterial remodeling due partially to PASMC proliferation are the major causes for increased pulmonary vascular resistance and increased pulmonary arterial pressure in patients with precapillary pulmonary hypertension (PH) including PAH and PH due to respiratory diseases or hypoxemia. We and others observed upregulation of TRPC6 channels in PASMCs from patients with PAH. A rise in cytosolic Ca2+ concentration ([Ca2+]cyt) in PASMC triggers PASMC contraction and vasoconstriction, while Ca2+-dependent activation of PI3K/AKT/mTOR pathway is a pivotal signaling cascade for cell proliferation and gene expression. Despite evidence supporting a pathological role of TRPC6, no selective and orally bioavailable TRPC6 antagonist has yet been developed and tested for treatment of PAH or PH. In this study, we sought to investigate whether block of receptor-operated Ca2+ channels using a nonselective blocker of cation channels, 2-aminoethyl diphenylborinate (2-APB, administered intraperitoneally) and a selective blocker of TRPC6, BI-749327 (administered orally) can reverse established PH in mice. The results from the study show that intrapulmonary application of 2-APB (40 µM) or BI-749327 (3-10 µM) significantly and reversibly inhibited acute alveolar hypoxia-induced pulmonary vasoconstriction. Intraperitoneal injection of 2-APB (1 mg/kg per day) significantly attenuated the development of PH and partially reversed established PH in mice. Oral gavage of BI-749327 (30 mg/kg, every day, for 2 wk) reversed established PH by ∼50% via regression of pulmonary vascular remodeling. Furthermore, 2-APB and BI-749327 both significantly inhibited PDGF- and serum-mediated phosphorylation of AKT and mTOR in PASMC. In summary, the receptor-operated and mechanosensitive TRPC6 channel is a good target for developing novel treatment for PAH/PH. BI-749327, a selective TRPC6 blocker, is potentially a novel and effective drug for treating PAH and PH due to respiratory diseases or hypoxemia.

Mineralocorticoid receptors in pulmonary hypertension and right heart failure: From molecular biology to therapeutic targeting

Pulmonary hypertension (PH) is a devastating condition characterized by pulmonary vascular remodelling, leading to progressive increase in pulmonary artery pressure and subsequent right ventricular failure. Aldosterone and the mineralocorticoid receptor (MR), a nuclear transcription factor, are key drivers of cardiovascular disease and MR antagonists are well-established in heart failure. Now, a growing body of evidence points at a detrimental role of MR in PH. Pharmacological MR blockade attenuated PH and prevented RV failure in experimental models. Mouse models with cell selective MR deletion suggest that this effect is mediated by MR in endothelial cells. While the evidence from experimental studies appears convincing, the available clinical data on MR antagonist use in patients with PH is more controversial. Integrated analysis of clinical data together with MR-dependent molecular alterations may provide insights why some patients respond to MRA treatment while others do not. Potential ways to identify MRA 'responders' include the analysis of underlying PH causes, stage of disease, or sex, as well as new biomarkers.

Recent advances in drug repurposing using machine learning

Drug repurposing aims to find new uses for already existing and approved drugs. We now provide a brief overview of recent developments in drug repurposing using machine learning alongside other computational approaches for comparison. We also highlight several applications for cancer using kinase inhibitors, Alzheimer's disease as well as COVID-19.