Age-associated changes to pathogen-associated molecular pattern-induced inflammatory mediator production in dogs.

OBJECTIVE: To determine whether older dogs will have a more pronounced pro-inflammatory response and blunted anti-inflammatory response to pathogen-associated molecular patterns (PAMPs) compared with younger dogs.
DESIGN: Prospective.
SETTING: University teaching hospital. ANIMALS: Thirty-eight privately owned sexually altered dogs of various ages.
INTERVENTIONS: Blood was collected for HCT, WBC count, plasma biochemical analysis, and whole blood culture. Whole blood was stimulated with lipopolysaccharide (LPS) or, lipoteichoic acid or, peptidoglycan or, addition of phosphate-buffered saline. Tumor necrosis factor (TNF), interleukin (IL)-6, and IL-10 production from whole blood were compared among young, middle aged, and geriatric dogs.
MEASUREMENTS AND MAIN RESULTS: LPS, lipoteichoic acid, and peptidoglycan stimulated significant TNF, IL-6, and IL-10 production from canine whole blood compared with phosphate-buffered saline. Whole blood from geriatric dogs had a blunted IL-10 response to LPS stimulation and middle-aged dogs had increased LPS-induced TNF production compared with the other groups.
CONCLUSION: PAMPs from gram-positive and gram-negative bacteria stimulate TNF, IL-6, and IL-10 production from canine whole blood. The inflammatory mediator response to PAMPs from gram-negative bacteria alters with age and may be one factor contributing to mortality in geriatric dogs with sepsis. © Veterinary Emergency and Critical Care Society 2010.