C-terminal telopeptide of type I collagen, osteocalcin, alkaline phosphatase, and parathyroid hormone in healthy and hospitalized foals.

The research investigates the relationship between varying levels of certain bone-turnover markers and the health of newborn foals, revealing potential associations with disease severity and survival chances. Elevated bone resorption levels could potentially signify critical illnesses in foals.

Study Overview

• The study targeted to measure three markers of bone resorption (C-terminal telopeptide of type I collagen [CTX-I]) and bone formation (osteocalcin [OCN]; alkaline phosphatase [ALP]) with their connection to Parathyroid hormone (PTH) levels, health severity, and mortality in hospitalized foals.
• It was a prospective and multicenter study that involved 75 newborn foals, divided into hospitalized—comprising both septic and sick nonseptic—and healthy groups.
• Blood samples were collected on admission, and the serum CTX-I, OCN, PTH, and ALP activities measured. Statistical analysis was conducted using nonparametric methods and univariate logistic regression.

Key Findings

• Serum CTX-I and PTH concentrations were significantly higher in septic foals than in healthy ones, while OCN concentrations were lower.
• Serum ALP activity didn’t differ between the groups; however, it was lower in hospitalized and septic foals with lower OCN concentrations.
• The PTH concentrations in hospitalized foals significantly correlated with CTX-I concentrations and negatively associated with ALP activity.
• High CTX-I levels and low OCN concentrations associated with severe illness.
• Non-surviving hospitalized foals had significantly lower OCN concentrations than survivors, whereas CTX-I levels were not associated with survival.
• Hospitalized foals with PTH concentrations more than 12.4 pmol/L had a higher likelihood of dying.

Interpretation and Conclusions

• Elevated PTH and CTX-I levels, together with reduced OCN concentrations and ALP activity, suggest that bone resorption is increased during critical sickness in foals. This could either be a compensatory mechanism from the body to correct hypocalcemia or a response to systemic inflammation and metabolic imbalances.
• This enhanced bone resorption could negatively affect the skeletal development of the growing foal.
• Low OCN and high PTH concentrations were found to be predictors of non-survival in hospitalized foals, highlighting the potential use of these markers in prognosis and management of critically ill foals.