C-terminal telopeptide of type I collagen, Osteocalcin, Alkaline Phosphatase, and Parathyroid Hormone in Healthy and Hospitalized Foals

Abstract Hypocalcemia is a common finding in critically ill equine patients. Parathyroid hormone (PTH) helps to maintain calcium homeostasis in hypocalcemic patients by promoting renal calcium reabsorption and bone resorption. Increased serum PTH concentrations have been reported in critically ill people and animals, including horses and foals. It is unknown whether increased secretion of PTH is associated with markers of bone turnover in hospitalized foals. The goals of this study were to measure markers of bone resorption (C-terminal telopeptide of type I collagen [CTX-I]) and bone formation (osteocalcin [OCN]; alkaline phosphatase [ALP]) and to determine their association with PTH concentrations, disease severity and mortality in hospitalized foals. This prospective, multicenter, cross-sectional study was conducted on 75 newborn foals ≤ 3 days old divided into hospitalized (n = 65; 41 septic; 24 sick non-septic [SNS]) and healthy (n = 10) groups. Blood samples were collected on admission to measure serum CTX-I, OCN, and PTH concentrations and ALP activity. Data were analyzed by non-parametric methods and univariate logistic regression. Serum CTX-I and PTH concentrations were significantly higher, while OCN concentrations were lower in septic compared to healthy foals (P 12.4 pmol/L were more likely to die (OR = 1.5; 95% CI = 1.1-4.16; P