Evaluation of TGFβ1, CCL2 and CXCL8 blood levels in healthy dogs from seven breeds differently predisposed to canine idiopathic pulmonary fibrosis ?

Canine idiopathic pulmonary fibrosis (CIPF) is a spontaneously occurring progressive lung disease sharing several features with human IPF. Amongst terrier breeds, the West Highland white terrier (WHWT) is particularly prone to CIPF. We hypothesized that higher circulating levels of pro-fibrotic proteins, or cytokines potentially involved in IPF pathogenesis, could serve as predisposing factors for CIPF development in the WHWT breed. Therefore, we collected serum samples from 103 healthy dogs of different breeds, including 18 WHWT, 14 Scottish terriers (ST), 16 Jack Russell terriers (JRT), 15 Maltese (M), 14 King Charles Spaniels (KCS), 12 Labradors (L) and 14 Belgian Shepherds (BS) considered as highly (WHWT),  mildly (ST, JRT, M,) or not (KCS, L, BS) -CIPF predisposed breeds. Serum levels of transforming growth factor beta-1 (TGFβ1), serotonin (5HT) and chemokines CCL2 and CXCL8 were measured by ELISA and compared between groups with a global linear model. CXCL8 serum levels were significantly higher in healthy WHWT compared to each of the other groups of healthy dogs. For TGFβ1, highest concentrations were found in the WHWT breed and the difference in comparison to other breeds was significant only with the JRT, KCS, L and BS breeds. For CCL2 and 5HT serum levels, no relevant inter-breed differences were observed. In conclusion, both CXCL8 and TGFβ1 basal blood levels might be related to the breed predisposition of the WHWT for CIPF, although such observations require further investigations.