Tenascin-C is a Promising Marker of High Bone Turnover and Vascular Calcification in Prevalent Hemodialysis Patients

Abstract

Abstract Background and Aims Tenascin-C (TN-C) is an extracellular matrix glycoprotein associated with high cell turnover and vascular calcification and atherosclerosis. This study determines the frequency of Tenascin-C in uncontrolled parathyroid hormone state and its relation to vascular calcification. Method A cross sectional study included 90 prevalent hemodialysis patients divided into 2 equal groups: uncontrolled iPTH level >300 pg /ml and controlled iPTH (150-300 pg/ml) groups. Serum Tenascin-C was measured by ELISA and vascular calcification was assessed by simple vascular calcification score (adragao score): by Plain X ray on hands, pelvis & vascular access for all patients. Results The prevalence of Tenascin-C and vascular calcification in patient with uncontrolled PTH were 84.4% (38 patients), 46.7% (21 patients) respectively. Tenascin-C was positively correlated with PTH level (r 0.494 p < 0.001) in patients with high bone turnover. Tenascin-C was high in patients with uncontrolled PTH [median (IQR) 637 (4245)u/ml] compared with patients with controlled PTH [median (IQR) 211 (143) u/ml] P value <0.0001. According to Adragao calcification score, in uncontrolled PTH: 31.1% (14 patients) had score 1 and 15.6% (7 patients) score 2. In controlled iPTH all patients had score 0. Patients with vascular calcification had high Tenascin-C median [(IQR) 10697 (53974)] compared with patients without vascular calcification [median (IQR)7697 (18000) u/ml)] P value <0.001. Serum Tenascin-C can predict high bone turnover at cutoff value 7377 ng/ml with AUC 0.794, sensitivity 84.4% and specificity 60 % while predict vascular calcification at cut of value > 8859 ng/ml AUC 0.745, sensitivity 72.7 %, specificity 72.1 %. Patients who have elevated level of tenascin C had 10.3, 3.7 times the risk to have high bone turnover and vascular calcification than negative one respectively. Conclusion Tenascin-C appears to be a sensitive marker for assessment of high bone turnover and vascular calcification in Prevalent Hemodialysis Patients.