Response of Hemopoietic, Progenitor, and Multipotent Mesenchymal Stromal Cells to Administration of Ketanserin during Pulmonary Fibrosis

Pathological Insight into 5-HT2B Receptor Activation in Fibrosing Interstitial Lung Diseases

Interstitial lung disease (ILD) encompasses a heterogeneous group of more than 200 conditions, of which primarily idiopathic pulmonary fibrosis (IPF), idiopathic nonspecific interstitial pneumonia, hypersensitivity pneumonitis, ILD associated with autoimmune diseases and sarcoidosis may present a progressive fibrosing (PF) phenotype. Despite different aetiology and histopathological patterns, the PF-ILDs have similarities regarding disease mechanisms with self-sustaining fibrosis, which suggests that the diseases may share common pathogenetic pathways. Previous studies show an enhanced activation of serotonergic signaling in pulmonary fibrosis, and the serotonin (5-HT)₂ receptors have been implicated to have important roles in observed profibrotic actions. Our research findings in support by others, demonstrate antifibrotic effects with 5-HT_2B receptor antagonists, alleviating several key events common for the fibrotic diseases such as myofibroblast differentiation and connective tissue deposition. In this review, we will address the potential role of 5-HT and in particular the 5-HT_2B receptors in three PF-ILDs: ILD associated with systemic sclerosis (SSc-ILD), ILD associated with rheumatoid arthritis (RA-ILD) and IPF. Highlighting the converging pathways in these diseases discloses the 5-HT_2B receptor as a potential disease target for PF-ILDs, which today have an urgent unmet need for therapeutic strategies.

Assessment of the possible roles of SB-269970 versus ketanserin on carbon tetrachloride-induced liver fibrosis in rats: Oxidative stress/TGF-β1-induced HSCs activation pathway

BACKGROUND

In liver fibrosis, a major morbid and mortal disease, oxidative stress motivation of hepatic stellate cells (HSCs)-into myofibroblasts terminated in collagen deposition remain the key pathophysiological deal. Serotonin (5-HT) through its HSCs-expressed receptors, especially 5-HT2A and 7, shows crucial events in fibrogenesis of chronic liver diseases. Molecular hepatic oxidative stress-fibrotic roles of 5-HT2A and 7 receptors antagonists (ketanserin and SB-269970 respectively) are still a challenging issue.

METHODS

Seven groups of adult male Wistar rats (n=10) were used. A carbon tetrachloride (CCl₄) solution was injected intraperitoneally twice weekly for 6 weeks. On the 7th week, rats developed liver fibrosis were treated either by ketanserin (1mg/kg/day, ip) or SB-269970 (2mg/kg/day, ip) for 14days. Survival rates, and serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels in addition to hepatic malondialdehyde (MDA) and reduced glutathione (GSH) levels, superoxide dismutase (SOD) and catalase (CAT) activities, and transforming growth factor-beta1 (TGF-β₁) and procollagen type I N-terminal propeptide (PINP) levels, beside the hepatic histopathological fibrotic changes, were evaluated.

RESULTS

In CCl₄-challenged rats, each therapeutic approach showed significant reductions in elevated serum ALT, and AST levels, hepatic MDA, TGF-β₁, and PINP levels, and histopathological hepatic fibrotic scores as well as significant elevations in survival rates, reduced hepatic GSH levels, and SOD, and CAT activities. Remarkably, significant ameliorative measurements were observed in SB-269970 treated group.

CONCLUSION

Blockade of 5-HT2A and 7 receptors each alone could be a future reliable therapeutic approach in liver fibrosis through a reduction in oxidative stress/TGF-β₁-induced HSCs activation pathway.