MO480FGF-23 AND LOW BIRTH WEIGHT: IS THERE ANY ASSOCIATION?

Abstract

Abstract Background and Aims According to Barker’s theory and Brenner’s hypothesis, persons were born with low birth weight (LBW) have a higher risk of CKD due to low nephron number. Also, it is well known that mineral-bone disorder (MBD) is one of the most serious complications of CKD. Views on the pathogenesis of CKD-MBD have changed considerably since Fibroblast growth factor 23 (FGF-23) was discovered. It is thought that FGF-23 increases as the nephron mass reduces. Therefore, we aimed to determine if there is an association between LBW and FGF-23. Method We conducted a cross-sectional study on 56 children with CKD stages 1-4. There were approximately equal numbers of participants in each stage. The mean age was 8.9 ±4.9 years old. We measured the concentration of FGF-23 (C-terminal) in serum by a sandwich enzyme-linked immunosorbent assay (ELISA) kit (Biomedica Medizinprodukte GmbH, Austria). The exclusion criteria: tubulopathy, active inflammatory, infectious, oncological and bone diseases, renal transplant, as well as taking steroids, calcium, and vitamin D. The informed consent was obtained from the parents. The study was conducted in accordance with the Declaration of Helsinki and approved by the Local Ethical Committee. FGF-23 concentration more than 1.5 pmol/l was considered as abnormal. Statistical analysis was performed using GraphPad Prism 9.0.0 (San Diego, USA) Results Mineral-bone disorder was diagnosed as CKD complication in 20 (35.7%) children. LBW was revealed in 14 (25%) patients. The median (IQR) eGFR among patients with normal birth weight was 65.23 (31.23-84.73) ml/min/1.73m2, among LBW – 68.93 (24.59-98.9) ml/min/1.73m2, so there were no differences in kidney function between the two groups (p=0.64). The median (IQR) level of serum FGF-23 in patients with normal birth weight was 1.75 (0.68- 2.5) pmol/l, in LBW children was 1.85 (0.78 -3.1) pmol/l. Analysis of serum level of FGF-23 in relation to weight at birth revealed no statistical differences in patients with LBW and those with normal birth weight (p=0.719), and the Spearman rank correlation was insignificant as well (r=-0.08, p=0.560). Conclusion FGF-23 is an important biomarker of CKD-MBD. FGF-23 does not depend on the birth weight although LBW is considered as a risk factor for CKD. However, further investigations and studies in this area are needed to make the right conclusions regarding the association between this bone biomarker and birth weight.