IM02 - Pilot Evaluation of Inflammatory Markers in Aging Dogs

Abstract: Background: In people, plasma inflammatory markers tumor necrosis factor-α (TNF-α), interluken-6 (IL-6), and C-reactive protein (CRP) increase with age and are predictors of mortality.

Objectives: To characterize the effects of age, sex, weight, and body condition score (BCS) on serum S100A12, N-methylhistamine (NMH), CRP , interleukins (ILs)-2,6,8, and TNF-α concentrations in healthy companion dogs

Animals: 49 healthy dogs enrolled in the Dog Aging Project (DAP) Pack with banked serum samples

Methods: Dogs were determined to be healthy on the basis of a lack of owner-reported diseases, review of electronic medical records, and normal bloodwork. Serum ILs and TNF-α concentrations were measured using a multiple electrochemiluminescence immunoassay validated in dogs. Serum S100A12 and NMH concentrations were determined using sandwich ELISA tests and gas chromatography-mass spectrometry, respectively. BCS was assigned by a single observer reviewing owner-provided photographs. Association of inflammatory markers with age, sex, weight, and BCS was evaluated by linear regression.

Results: There was no effect of BCS on any inflammatory measure. Positive associations were identified between age and several cytokines: IL-2 (P = .0191), IL-6 (P = .0005), IL-8 (P = .0059), and TNF-α (P = .00067), and between female sex and NMH (P=.0168). A negative association was identified between IL-8 and weight, with smaller dogs having higher concentrations than large dogs (P = .0078).

Conclusions and clinical importance: Association of cytokines (IL-2, IL-6, IL-8, and TNF-α) with age and IL-8 with dog size warrant further evaluation in a larger population.