Transfer of tumour necrosis factor-α via colostrum to foals

Tumor necrosis factor-α is transferred to equine neonates via colostrum but is not associated with their health status

We followed the hypothesis that equine neonates with reduced transfer of tumor necrosis factor-α (TNFα) are at increased risk of neonatal infection. We investigated TNFα concentrations in colostrum of healthy mares and blood of their neonates in a non-hospitalized population of Warmblood mares where delivery, neonatal adaptation and health was closely monitored by veterinarians. Concentration of TNFα and IgG was determined in colostrum respective milk and in neonatal blood collected immediately after delivery and 18 h thereafter in 97 foals that were assigned to groups failure of passive transfer (FPT; n = 31) and control (CON; n = 66) based on serum IgG concentration at 18 h of age. Foal health was assessed repeatedly during the first 24 h of life. Statistical analysis was done with p < 0.05 indicating significance. There were no significant differences between foal groups FPT and CON regarding age and parity of dams, gestation length (FPT 343 ± 10, CON 340 ± 8 days) and foal sex. Concentrations of TNFα in colostrum at birth and in foals at 18 h varied but did not differ between groups (colostrum FPT 6.1 ± 9.1, CON 9.9 ± 31.5 ng/ml; foal FPT 2.3 ± 5.9, CON 2.4 ± 5.3 ng/ml; n.s.). There was an increase in the mean serum TNFα concentration until 18 h in foals (n.s. between groups). Results of the present study confirm previous findings of TNFα transfer from the mare to the neonate via colostrum but do not suggest that transfer of TNFα via colostrum is important for protection of the neonate against infectious diseases.

Effect of plasma transfusion on serum amyloid A concentration in healthy neonatal foals and foals with failure of transfer of passive immunity

BACKGROUND

Anecdotal evidence suggests plasma transfusions increase serum amyloid A (SAA) concentrations in healthy neonatal foals making this marker of inflammation inappropriate for therapeutic decision making in such animals.

HYPOTHESIS/OBJECTIVES

Administration of hyperimmune fresh frozen plasma (FFP) increases SAA concentration in healthy foals and in foals with failure of transfer of passive immunity (FTPI).

ANIMALS

Eighty-six healthy foals.

METHODS

Prospective cohort study. Foals <24 hours of age receiving plasma transfusion for treatment of FTPI (serum immunoglobulin G [IgG] concentrations <8 g/L; n = 17) or as a preventative measure for Rhodococcus equi infection (IgG >8 g/L; n = 33) were enrolled. A healthy nontransfused group of foals (IgG >8 g/L; n = 21) also was included. Serum amyloid A concentration was determined before (t0h) and after (t24h) administration of FFP. Changes in blood SAA concentration were assessed using linear regression models.

RESULTS

No statistical differences were found in SAA concentration at t0h or t24h among the 3 groups (P > .05, for all comparisons). The variation in SAA concentration before (t0h) and after (t24h) plasma transfusion showed that administration of FFP was not associated with the changes in SAA concentration (P > .05). An association between SAA concentration at t0h and at 24 hours (P < .05) was identified, where foals with higher SAA concentration at t0h also had higher SAA concentration at t24h.

CONCLUSIONS AND CLINICAL IMPORTANCE

Administration of FFP to newborn foals was not associated with changes in SAA concentration.

Cytokine levels in colostrum and in foals' serum pre- and post-suckling

The purpose of this study is to investigate the presence of IL-4, IL-8, IL-13 and IFN-γ in equine colostrum and in foals' serum. Samples were obtained from 14 mares and their healthy foals. Soon after parturition, 10ml of colostrum was collected, filtered, centrifuged and frozen until assayed. Blood samples were obtained from each foal at birth (TO) and again after 24h (T24), after which they were frozen until assayed. Serum IgG was measured at 24h of age with an immunoturbidimetric quantitative method. Cytokine concentration was determined using commercially available ELISA tests. Statistical analyses revealed a significant difference in serum concentration of IL-4 at T0 and at T24 (p<0.05) and a significant correlation between the serum IL-4 at T24 and colostral IL-4. These results suggest the absorption of IL-4 from colostrum. The presence of IL-8 in the pre-suckle foal's serum may be due to an endogenous production. With the exception of two samples, there was no IL-13 detected in the foals' serum at birth and remained undetectable in 8/14 samples after 24h. This cytokine was also undetectable in four colostrum samples, where its concentration showed a wide range and a high standard deviation. IFN-γ was present in both the colostrum and in the foals serum at birth.

Maternal T-lymphocytes in equine colostrum express a primarily inflammatory phenotype

The purpose of this study was to characterize maternal immune cells in colostrum of mares. Cell phenotypes and cytokine secretion from mare peripheral blood mononuclear cells (PBMC) and cells from colostrum were analyzed by flow cytometry and by multiplex cytokine analysis. Equine colostral leukocytes were composed of mainly CD8(+) and CD4(+) lymphocytes. CD8(+) cells were significantly enriched in colostrum compared to PBMC (n=35). Colostral T-cells (n=13) responded to stimulation with PMA/ionomycin with a significantly higher magnitude of IL-17 (p=0.037) and similar IFN-γ concentrations (p=0.305), while IL-4 (p=0.0002) and IL-10 (p=0.0002) production was decreased compared to PBMC. CD4(+) and CD8(+) T-cells in colostrum produced IFN-γ (n=4). The findings show that colostrum T-cells can produce all four cytokines investigated here but most cells are polarized toward IL-17 and IFN-γ production and an inflammatory phenotype. Maternal T-cells likely migrate to the colostrum in a selective manner and may have specific roles in neonatal immune development.

Equine colostral carbohydrates reduce lipopolysaccharide-induced inflammatory responses in equine peripheral blood mononuclear cells

REASONS FOR PERFORMING STUDY

Increasing evidence suggests that reactions to lipopolysaccharide (LPS), particularly in the gut, can be partly or completely mitigated by colostrum- and milk-derived oligosaccharides. Confirmation of this hypothesis could lead to the development of new therapeutic concepts.

OBJECTIVES

To demonstrate the influence of equine colostral carbohydrates on the inflammatory response in an in vitro model with equine peripheral blood mononuclear cells (PBMCs).

METHODS

Carbohydrates were extracted from mare colostrum, and then evaluated for their influence on LPS-induced inflammatory responses in PBMCs isolated from the same mares, mRNA expression of tumour necrosis factor-alpha, interleukin-6 and interleukin-10 was measured as well as the protein levels of tumour necrosis factor-alpha (TNF-alpha) and interleukin-10 (IL-10).

RESULTS

Equine colostral carbohydrates significantly reduced LPS-induced TNF-alpha protein at both times measured and significantly reduced LPS-induced TNF-alpha, IL-6 and IL-10 mRNA expression by PBMCs. Moreover, cell viability significantly increased in the presence of high concentrations of colostral carbohydrates.

CONCLUSIONS

Carbohydrates derived from equine colostrum reduce LPS-induced inflammatory responses of equine PBMCs.

POTENTIAL RELEVANCE

Colostrum and milk-derived carbohydrates are promising candidates for new concepts in preventive and regenerative medicine.