TY - JOUR T1 - Fibroblast Growth Factor 23 Levels in Pulmonary Involvement Associated With Systemic Sclerosis: A Proof-of-concept Study JF - The Journal of Rheumatology JO - J Rheumatol SP - 542 LP - 544 DO - 10.3899/jrheum.211156 VL - 49 IS - 5 AU - Luis M. Amezcua-Guerra AU - Mauricio Mora-Ramirez AU - Gonzalo Vancini AU - Valentín Jimenez-Rojas AU - Ricardo Márquez-Velasco Y1 - 2022/05/01 UR - http://www.jrheum.org/content/49/5/542.abstract N2 - To the Editor:Systemic sclerosis (SSc) is a devastating disease associated with lung involvement, primarily interstitial lung disease (ILD) and pulmonary hypertension (PH).1 Although computed tomography (CT) and right heart catheterization accurately identify cardiopulmonary injury,2 their high cost and technical complexity make them inaccessible to most nonspecialized health centers. Thus, the timely detection of lung involvement remains a challenge in real-world settings.A pathogenic link between autoimmunity, inflammation, and vitamin D imbalance is axiomatic in SSc. Closely associated with vitamin D metabolism is fibroblast growth factor 23 (FGF23), a protein secreted by osteocytes and osteoblasts that plays a role in the bone-kidney axis and calcium-phosphorus balance.3 A recent study demonstrated that the endothelin-1 (ET-1) receptor, a critical regulator of vascular tone and endothelial proliferation in the lungs, controls the cellular production of FGF23, positioning this molecule as a potential biomarker of clinical relevance.4To assess the feasibility of FGF23 as a marker of lung involvement, we conducted a proof-of-concept study in 29 patients with SSc.1 Evaluation included skin involvement (modified Rodnan skin score [mRSS]), accumulated organ damage (Medsger Disease Severity Scale [MDSS]), and disease activity (Valentini … ER -