SIRT1 and pulmonary fibrosis: For example, Chu et al. demonstrated that deacetylase Sirtuin 1 was underexpressed in the peripheral blood mononuclear cells (PBMCs) of SSc patients with lung fibrosis, and its activation in bleomycin-treated mice or overexpression in human lung fibroblasts reduced collagen production and ameliorated the fibrotic response [119].