Arthritis & Rheumatism, Volume 62,
November 2010 Abstract Supplement

Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Atlanta, Georgia November 6-11, 2010.


Fibroblast Growth Factor (FGF23) Serum Levels in Juvenile Onset Systemic Lupus Erythematosus (JSLE): A Potential Link with Renal Involvement.

Falcini1,  Fernanda, Masi2,  Laura, Capannini1,  Serena, Franceschelli2,  Francesco, Leoncini2,  Gigliola, Denaro1,  Valentina, Francesco3,  La Torre

Dpt of BioMedicine, Rheumatology Section, Transition Unit, University of Florence
Dpt of Internal Medicine, Metabolic Bone Diseases Unit, University of Florence, Florence
Dpt of Paediatrics, Rheumatology Unit, University of Messina, Messina, Italy

Background:

Phosphatonins are involved in phosphate homeostasis, Vitamin D metabolism, and bone mineralization. FGF23, the master phosphatonin, acts through FGFr1 present in kidney, vessels and heart; its levels are high in chronic renal disease, and association between FGF23 levels and high death a part of other risk factors has been reported. JSLE is associated with high risk of atherosclerosis and cardiovascular disease. Endothelial dysfunction, by autoantibodies, ICC and cytokines play a role in vascular injury.

Objectives:

1.To evaluate the serum level of intact FGF23 in JSLE pts. 2.To correlate FGF23 values to lipid profile, renal function, renal biopsy, and cardiac data.

Patients and Methods:

53 consecutive pts (46 F 7 M, mean age at diagnosis 13.3±5.6) with SLE onset before 18 yrs entered the study. 12/53 had renal disease (GN) at onset while 13/53 developed GN signs over time. Steroids were the first drug in all pts, then hydroxychloroquine, AZA, CyA, and MMF while antiCD20 was applied to 3 pts. At study entry, the disease was controlled by hydroxychloroquine in 28/53, while in 25/53 with low dose prednisone, MMF or AZA; 1 pts developed renal failure and went on dialysis. All pts with GN were biopsied 6 mths from renal manifestations onset: 4 WHO IIA, 6 IIB, 10 III, 5 IV. 35 sex and age matched subjects acted as controls. Serum intact FGF23 levels were measured with an ELISA assay (Immunotopics Inc. San Clemente, CA, USA).

Results:

FGF23 serum levels resulted higher in JSLE pts than in controls (t-student:67.1±40SD vs 5±3.2SD pg/ml). By Mann-Whitney U Test; GN pts had FGF23 values higher than those without (45.3±20 vs 13,77±9.2 SD pg/ml; p=0.0001). By Ancova analysis pts with severe disease (WHO III-IV) had higher levels than patients with biopsies WHO IIA-IIB (52,5±21 and 58,5±15 pg/ml respectively vs 13.7±9 and 35±10 pg/ml p=0.004). No significant correlation was found among serum FGF23 levels, lipid profile and cardiac function. A trend characterized by an inverse correlation between FGF23 and HDL was found (r-0.07;p=n.s.).

Conclusion:

Serum FGF23 levels are higher in JSLE pts and seem to correlate with renal damage. FGF23 serum values should be a helpful biomarker for assessing the risk of renal damage, and helpful in pts with early kidney disease in whom FGF23 levels firstly increase. Data in a larger cohort of pts are needed to define the role of FGF23 in renal disease of JSLE pts.

To cite this abstract, please use the following information:
Falcini, Fernanda, Masi, Laura, Capannini, Serena, Franceschelli, Francesco, Leoncini, Gigliola, Denaro, Valentina, et al; Fibroblast Growth Factor (FGF23) Serum Levels in Juvenile Onset Systemic Lupus Erythematosus (JSLE): A Potential Link with Renal Involvement. [abstract]. Arthritis Rheum 2010;62 Suppl 10 :1155
DOI: 10.1002/art.28921

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