Pulmonary fibrosis is shortening survival and impairing quality of life in Rheumatoid Arthritis (RA) as well as in other connective tissue diseases. The impact of historically available and newer biologic therapies in altering the outcome of RA with pulmonary fibrosis (RA-ILD) is unknown; translational studies focused on the pathobiology and clinical studies focused on the treatment of RA-ILD are needed. Bone marrow (BM) mesenchymal stem cells (MSCs) are being considered as potential therapeutic agents in various inflammatory autoimmune diseases for their tissue-repair and anti-inflammatory tissue-protective properties. This study investigates the reserves and function, the molecular and proteomic profile and the differentiation potential of BM MSCs in patients with active rheumatoid arthritis (RA) without lung involvement and RA-ILD.
BM MSCs were studied in 10 healthy controls, 8 patients with rheumatoid arthritis without lung involvement and 8 patients with RA-ILD. MSCs were identified by their immunophenotypic characteristics and their potential to differentiate towards adipocytes/osteocytes/chondrocytes. We evaluated the mRNA expression of genes involved in the lung injury of pulmonary fibrosis, such as the axis of stromal-cell-derived factor-1 (SDF-1α)/CXCR4 in BM MSCs using quantitative RT-PCR.
The BM MSCs of RA and RA-ILD patients displayed normal immunophenotypic characteristics and differentiation potential. The biological axis of SDF-1a-CXCR4 has not been expressed in rheumatoid arthritis without lung involvement. A significant increase in SDF-1a-CXCR4 mRNA expression was detected in RA-ILD compared to controls.
The distinct SDF-1α- CXCR4 expression by RA-ILD MSCs in comparison to RA maybe explain the better prognosis of the latter group of patients.
These preliminary findings could have implications in developping more targeted therapies for RA-ILD.
Katerina Antoniou, No Financial Disclosure Information; No Product/Research Disclosure Information