#5547 serum periostin in kidney transplant recipients as a novel biomarker predicting renal function loss

Abstract Background and Aims Experimental studies have shown periostin is expressed throughout organogenesis, particularly within the kidney interstitium. Periostin is enhanced in different tissues of patients with nephropathy and has been considered as a candidate biomarker of kidney injury. Method Retrospective analysis of electronic medical record of one hundred and five kidney transplant recipients (KTRs) was performed. Only patients under sequential ambulatory care, with a history of at least 2 years post-transplant were included. Median (IQR) follow-up and time post-transplant was 4.42 (2.65, 4.58) and 4.29 (3.04, 8.07) years, respectively. Additionally, thirty-two health volunteers (HV) were enrolled. Biochemical testing was performed using commercially-available immunoassays. Results Median [IQR] serum periostin was significantly lower in KTRs as compared with HV (959 [732, 1204] vs. 1176 [997, 1408]; P<0.01). Higher serum periostin was observed in male patients (7.01 [6.84, 7.22] vs. 6.79 [6.64, 7.07], P<0.05) and a significant relationship was noted for interleukin 6 (IL6; r=0.24, P=0.01) and baseline estimated glomerular filtration (eGFR) (r=0.20, P=0.04). Patient age (P=0.60), body-mass index P=0.08), cardiovascular disease (P=0.31), diabetes (P=0.45), current smoker status (P=0.27), nor anemia (P=0.23) were not associated with serum periostin. In a generalized additive model adjusted for baseline renal function and IL-6, serum periostin showed a signficant nonlinear association (P=0.04) with eGFR change over follow-up. Conclusion Previous studies reported an association between periostin expression and the severity of histological injury within the kidney in both inflammatory and non-inflammatory conditions. Serum periostin may be a potential marker aiding in prediction of renal function in KTRs.