Antifibrotics in systemic sclerosis

Nephroprotective effects of the soluble guanylyl cyclase stimulator, riociguat in doxorubicin-induced acute kidney injury in rats

This study aimed to investigate the potential protective effects of riociguat, a soluble guanylyl cyclase (sGC) stimulator, on kidney function and structure in rats with acute kidney injury (AKI) induced by the chemotherapeutic drug doxorubicin (DX). Rats were subjected to a single intraperitoneal injection of DX (13.5 mg/kg) on the 5th day, either alone or in combination with low-dose riociguat (3 mg/kg/day), or high-dose riociguat (10 mg/kg/day) for 8 consecutive days. Various markers related to kidney function, oxidative stress, and inflammation were measured in plasma and urine. Kidney tissues were examined histopathologically. DX-induced nephrotoxicity was characterized by increased plasma urea, creatinine, uric acid and neutrophil gelatinase-associated lipocalin (NGAL). DX also decreased creatinine clearance and albumin levels and increased urinary N-acetyl-β-D-glucosaminidase (NAG) activity. Furthermore, DX increased the inflammatory markers interleukin 1 beta (IL-1 β), interleukin 6 (IL-6) and tumor necrosis factor alpha (TNF-α). DX further induced oxidative stress injury evidenced by decreased glutathione reductase (GR) activity, total antioxidant capacity (TAC), superoxide dismutase (SOD) and catalase levels and increased malondialdehyde (MDA) levels. Concomitant treatment with riociguat ameliorated these DX-induced changes with parallel histopathological improvements but the effects were more favorable with high-dose riociguat. The observed renoprotective effects of riociguat can be partly attributed to the anti-inflammatory and anti-oxidant properties of this drug.

Progress in research on mesenchymal stem cells and their extracellular vesicles for treating fibrosis in systemic sclerosis

Systemic sclerosis (SSc) refers to an autoimmune disease characterized by immune dysfunction, vascular endothelial damage, and multi-organ fibrosis. Thus far, this disease is incurable, and its high mortality rate is significantly correlated with fibrotic events. Fibrosis has been confirmed as a difficult clinical treatment area that should be urgently treated in clinical medicine. Mesenchymal stem cells (MSCs) exhibit immunomodulatory, pro-angiogenic, and anti-fibrotic functions. MSCs-derived extracellular vesicles (EVs) have aroused rising interest as a cellular component that retains the functions of MSCs while circumventing the possible adverse effects of MSCs. Moreover, EVs have great potential in treating SSc. In this study, the current research progress on MSCs and their EVs for treating fibrosis in SSc was reviewed, with an aim to provide some reference for future MSCs and their EVs in treating SSc.

Management of Connective Tissue Disease-related Interstitial Lung Disease

Purpose of Review

This review aims to collate current evidence on the screening, diagnosis, and treatment of various connective tissue disease (CTD)-associated interstitial lung diseases (CTD-ILD) and present a contemporary framework for the management of such patients. It also seeks to summarize treatment outcomes including efficacy and safety of immunosuppressants, anti-fibrotics, and stem cell transplantation in CTD-ILD.

Recent Findings

Screening for ILD has been augmented by the use of artificial intelligence, ultra-low dose computerized tomography (CT) of the chest, and the use of chest ultrasound. Serum biomarkers have not found their way into clinical practice as yet. Identifying patients who need treatment and choosing the appropriate therapy is important to minimize the risk of therapy-related toxicity. The first-line drugs for systemic sclerosis (SSc) ILD include mycophenolate and cyclophosphamide. Nintedanib, an anti-fibrotic tyrosine kinase inhibitor, is approved for use in SSc-ILD. The US Food and Drug Administration (FDA) has recently approved tocilizumab subcutaneous injection for slowing the rate of decline in pulmonary function in adult patients with SSc-ILD. Autologous stem cell transplantation may have a role in select cases of SSc-ILD.

Summary

CTD-ILD is a challenging area with diverse entities and variable outcomes. High-resolution CT is the investigative modality of choice. Treatment decisions need to be individualized and are based on patient symptoms, lung function, radiologic abnormalities, and the risk of disease progression. Precision medicine may play an important role in determining the optimal therapy for an individual patient in the future.

Serine-Threonine Kinase inhibition as antifibrotic therapy: TGF-β and ROCK inhibitors

Serine-threonine kinases mediate the phosphorylation of intracellular protein targets, transferring a phosphorus group from an ATP molecule to the specific amino acid residues within the target proteins. Serine-threonine kinases regulate multiple key cellular functions. From this large group of kinases, transforming growth factor beta (TGF-β) through the serine-threonine activity of its receptors and Rho kinase (ROCK) play an important role in the development and maintenance of fibrosis in various human diseases, including systemic sclerosis. In recent years, multiple drugs targeting and inhibiting these kinases, have been developed, opening the possibility of becoming potential antifibrotic agents of clinical value for treating fibrotic diseases. This review analyzes the contribution of TGF- β and ROCK-mediated serine-threonine kinase molecular pathways to the development and maintenance of pathological fibrosis and the potential clinical use of their inhibition.

Relevance of immunomodulatory therapy for interstitial lung disease in systemic sclerosis

Systemic sclerosis is an autoimmune disease that prominently leads to skin and tissue fibrosis. The efficacy of autologous stem cell transplantation not only attests to the autoimmune pathophysiology for systemic sclerosis, but also for interstitial lung disease as its most frequent manifestation of fatal organ involvement. Accordingly, a variety of immunomodulatory therapies were tried on patients with systemic sclerosis-interstitial lung disease. Until very recently, all of these therapeutic approaches constituted off-label treatment for systemic sclerosis, given that neither of these therapies was approved by the United States Food and Drug Administration (FDA) or the European Medicines Agency. For tocilizumab, this has now changed with FDA approval in March 2021. Already 2020, nintedanib, which is an antifibrotic drug that does not target autoimmunity, became the first approved drug for interstitial lung disease in systemic sclerosis. The present review analyzes the evidence for immunomodulatory treatment of systemic sclerosis-associated interstitial lung disease. The review focuses on randomized controlled trials, which provides evidence for the effects of drugs such as cyclophosphamide, mycophenolate, rituximab and tocilizumab.