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Journal of veterinary internal medicine2025; 39(2); e70012; doi: 10.1111/jvim.70012

Longitudinal Evaluation of Vitamin D, Parathyroid Hormone, Antimicrobial Peptides, and Immunomodulatory Genes in Hospitalized Foals.

Abstract: Information about the association of antimicrobial peptides with hypovitaminosis D in hospitalized foals is lacking. Objective: We aimed to longitudinally determine the association of serum concentrations of vitamin D metabolites, vitamin D binding protein (DBP), and parathyroid hormone (PTH) with antimicrobial peptides (β-defensin-1 and cathelicidin-1) and the mRNA expression of the vitamin D receptor (VDR), 1α-hydroxylase (CYP27B1), 24-hydroxylase (CYP24A1), toll-like receptor-4 (TLR-4), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), disease severity, and mortality in hospitalized foals. We hypothesized that hypovitaminosis D would be associated with decreased serum concentrations of antimicrobial peptides, disease severity, and mortality in hospitalized foals. Methods: One hundred nine foals ≤ 72 h of age divided into hospitalized (n = 83; 60 septic, 23 sick nonseptic [SNS]) and healthy (n = 26) foals. Methods: Blood samples were collected on admission (0), and 24, 48, and 72 h after admission from healthy and hospitalized foals. Data were analyzed by repeated measure methods. Results: Serum 25(OH)D, 1,25(OH)2D, DBP, β-defensin-1, and cathlicidin-1 concentrations were significantly lower, whereas PTH concentrations were higher in hospitalized compared to healthy foals at different times during hospitalization (p < 0.05). Septic foals had lower VDR and CYP27B1, but higher TLR-4, TNF-α, and IL-1β mRNA expression than in healthy foals (p < 0.05). Decreased serum 25(OH)D, β-defensin-1, and cathelicidin-1, and high PTH concentrations were associated with higher odds of death in hospitalized foals (p < 0.05). Conclusions: Decreased vitamin D metabolite concentrations and decreased antimicrobial peptide concentrations suggest that vitamin D has important immunomodulatory functions in newborn foals.
© 2025 The Author(s). Journal of Veterinary Internal Medicine published by Wiley Periodicals LLC on behalf of American College of Veterinary Internal Medicine.
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Publication Date: 2025-02-26 PubMed ID: 40008921PubMed Central: PMC11863360DOI: 10.1111/jvim.70012Google Scholar: Lookup
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Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

This study explores the connection between low vitamin D levels, antimicrobial peptides and disease severity in hospitalized newborn horses, also called foals. The researchers found that foals who exhibited low vitamin D levels and reduced antimicrobial peptides had increased chances of disease severity and mortality.

Research Objective and Hypothesis

  • The main objective of the study was to examine longitudinal changes in serum concentrations of vitamin D metabolites, vitamin D binding protein, parathyroid hormone and their association with antimicrobial peptides and expression of various genetic markers and disease severity and mortality in hospitalized foals.
  • The researchers hypothesized that low levels of vitamin D, known as hypovitaminosis D, would be connected with decreased serum concentrations of antimicrobial peptides – important part of immune response, disease severity, and increased mortality in hospitalized foals.

Methodology

  • The study was carried out on 109 foals around 72 hours old, the sample was divided into three groups: 83 hospitalized foals further grouped into 60 septic foals, 23 sick non-septic foals, and 26 healthy foals.
  • Blood samples were collected from the foals upon admission and 24, 48, and 72 hours following admission.
  • The data were analyzed using techniques to measure repeated outcomes at multiple time points.

Results

  • The analysis revealed that hospitalized foals had significantly lower concentrations of 25(OH)D (a vitamin D metabolite), 1,25(OH)D (another vitamin D metabolite), vitamin D binding protein, β-defensin-1 (an antimicrobial peptide), and cathlicidin-1 (another antimicrobial peptide) compared to healthy foals.
  • Parathyroid hormone concentrations were higher in hospitalized foals than healthy foals at various times during the hospitalization.
  • Further, septic foals demonstrated lower expression of vitamin D receptor and 1α-hydroxylase, but higher expression of toll-like receptor-4, tumor necrosis factor-α, and interleukin-1β genes than in healthy foals.
  • Decreased serum concentrations of 25(OH)D, β-defensin-1, cathelicidin-1, combined with high parathyroid hormone concentrations, were associated with higher chances of mortality in hospitalized foals.

Conclusion

  • Based on the results of the study, lower vitamin D levels (its metabolite concentrations) and decreased concentrations of antimicrobial peptides suggest that vitamin D has significant functions in modulating the immune responses in newborn foals.
  • From these findings, it is clear that maintaining adequate vitamin D levels could potentially contribute to improved health outcomes in hospitalized foals.

Cite This Article

APA
Kamr AM, Bartish C, Summers J, Horton J, Hostnik LD, Orr K, Browne N, Dembek KA, Saliba C, Gomez DE, Toribio RE. (2025). Longitudinal Evaluation of Vitamin D, Parathyroid Hormone, Antimicrobial Peptides, and Immunomodulatory Genes in Hospitalized Foals. J Vet Intern Med, 39(2), e70012. https://doi.org/10.1111/jvim.70012

Publication

Journal of veterinary internal medicine
ISSN: 1939-1676
NlmUniqueID: 8708660
Country: United States
Language: English
Volume: 39
Issue: 2
Pages: e70012

Researcher Affiliations

Kamr, Ahmed M
  • College of Veterinary Medicine, The Ohio State University, Columbus, Ohio, USA.
  • Faculty of Veterinary Medicine, University of Sadat City, Sadat City, Egypt.
Bartish, Celine
  • College of Veterinary Medicine, The Ohio State University, Columbus, Ohio, USA.
Summers, Jamie
  • College of Veterinary Medicine, The Ohio State University, Columbus, Ohio, USA.
Horton, Julia
  • College of Veterinary Medicine, The Ohio State University, Columbus, Ohio, USA.
Hostnik, Laura D
  • College of Veterinary Medicine, The Ohio State University, Columbus, Ohio, USA.
Orr, Kindra
  • Rood and Riddle Equine Hospital, Lexington, Kentucky, USA.
Browne, Nimet
  • Hagyard Equine Medical Institute, Lexington, Kentucky, USA.
Dembek, Katarzyna A
  • College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina, USA.
Saliba, Caroline
  • Rood and Riddle Equine Hospital, Lexington, Kentucky, USA.
Gomez, Diego E
  • Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada.
Toribio, Ramiro E
  • College of Veterinary Medicine, The Ohio State University, Columbus, Ohio, USA.

MeSH Terms

  • Animals
  • Horses
  • Vitamin D / blood
  • Horse Diseases / blood
  • Horse Diseases / mortality
  • Female
  • Male
  • Antimicrobial Peptides / blood
  • Parathyroid Hormone / blood
  • Longitudinal Studies
  • Cathelicidins / blood
  • Vitamin D-Binding Protein / blood
  • beta-Defensins / blood
  • Receptors, Calcitriol / genetics
  • Receptors, Calcitriol / metabolism
  • Vitamin D Deficiency / veterinary
  • Vitamin D Deficiency / blood
  • 25-Hydroxyvitamin D3 1-alpha-Hydroxylase / genetics
  • RNA, Messenger / metabolism
  • RNA, Messenger / genetics

Grant Funding

  • AWD-107270 / Grayson-Jockey Club Research Foundation
  • 520510 / The Ohio State University Equine Research Funds

Conflict of Interest Statement

Authors declare no off‐label use of antimicrobials. The authors declare no conflicts of interest.

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