The FGF-23/klotho axis and its relationship with phosphorus, calcium, vitamin D, PTH, aldosterone, severity of disease, and outcome in hospitalised foals.

The research article studies the relationship between FGF-23 or fibroblast growth factor-23 and klotho with various elements such as phosphorus, calcium, and vitamin D, as well as their impacts on the severity of the disease and mortality in hospitalized foals.

Objective and Methodology

• The research aimed to measure the serum FGF-23 and klotho concentrations in foals and determine their associations with various serum factors such as phosphorus, total calcium (TCa), Vitamin D metabolites, parathyroid hormone (PTH), and aldosterone concentrations. It also looked at their relationship with disease severity and mortality in hospitalized foals.
• The study employed a prospective, multi-centre, cross-sectional methodology. A total of 91 foals, 72 hours or less old, were classified as hospitalized (81 in number, including 58 septic and 23 sick non-septic [SNS]) and healthy (10 foals).
• Blood samples were collected upon admission, and hormone concentrations were determined using immunoassays.

Results and Findings

• The result showed that serum FGF-23, PTH, phosphorus, and aldosterone concentrations were higher while klotho, 25(OH)D, 1,25(OH) D, and TCa concentrations were lower in septic and SNS compared to healthy foals.
• In hospitalized and septic foals, increased FGF-23 and aldosterone concentrations were associated with high phosphorus and PTH but not with TCa and vitamin D metabolite concentrations.
• Hospitalized foals with the highest FGF-23 and lowest klotho concentrations were more likely to die, highlighting their potential as markers of disease severity and likelihood of mortality.

Conclusions

• Imbalances in the FGF-23/klotho axis may contribute to mineral dyshomeostasis and disease progression in critically ill foals.
• A combination of elevated FGF-23 and reduced klotho with high phosphorus and PTH concentrations suggests FGF-23 resistance, which could be detrimental to the health of the foals.
• The study also found indication of the influence aldosterone may have over phosphorus and PTH dynamics in hospitalized foals.
• The researchers recommend routine measurement of phosphorus concentrations in sick foals for early detection and effective treatment.