Changes in lung mechanics and reactivity with age after viral bronchiolitis in beagle puppies

Abstract

We measured changes with growth in lung function and airway reactivity after acute canine parainfluenza virus type 2 (CPI2, n = 5), canine adenovirus type 2 (CAV2, n = 7), and sequential CAV2-CPI2 (n = 6) infections or no infection (controls, n = 6) in beagle puppies (age approximately 79 days). In the CPI2 and CAV2 groups, a lower respiratory illness developed by day 3 postinfection with clinical recovery by day 14. In the CAV2-CPI2 group, puppies were inoculated initially with CAV2 and 12 days later with CPI2. In this group, illness persisted until day 14 after infection with CPI2. Lung resistance (RL), dynamic (Cdyn) and static (Cst) lung compliance, functional residual capacity (FRC), and responsiveness to aerosolized histamine were measured before infection and at periodic intervals until 239 +/- 43 days of age. Lung function data were analyzed using a longitudinal random effects model. In all groups, FRC, Cst, and Cdyn increased with age. In all infected groups, the regression slopes for Cdyn were steeper than in controls. RL decreased linearly with age without group slope differences. Histamine reactivity increased with age, but there were no differences in slope among groups. Lung pathological studies showed areas of obliterative bronchiolitis and chronic small airways inflammation particularly in the CAV2 and CAV2-CPI2 groups. Thus, viral bronchiolitis produces chronic small airways inflammation in beagle puppies and alters the changes in lung function occurring with growth. Histamine reactivity increases with age and is not modified by viral infection.

Changes in lung mechanics and histamine responsiveness after sequential canine adenovirus 2 and canine parainfluenza 2 virus infection in beagle puppies

“…This observation is consistent with our previous study indicating that effects on subsequent lung growth are the same in CAV2-CP12 puppies as in CP12 or CAVZ infected puppies alone. 25 We have recently demonstrated that over a period of approximately 239 days, airway res nsiveness to histamine gradually increased with age.2qowever, we do not believe that the increased histamine responsiveness noted in the CAV2-CP12 group can be explained by our previous observation. First, the disparity in age at the time of CP12 infection in the CAV2-CP12 and CP12 groups was only 14 days which is too short a time to distinguish any age related differences in airway responsiveness.…”

Bronchiolitis Obliterans Organizing Pneumonia in Swine Associated with Porcine Circovirus Type 2 Infection

“…To date, several etiologies have also implicated in the pathogenesis of animal BOOP. Experimentally infected dogs with adenovirus [42][43][44], Mycoplasma [45], or cattle clinical infected bovine respiratory syncytial virus pneumonia occasionally develop BOOP [46]. Accidental intra-airway exposure of dog with a noninfectious agent oleic acid also induced BOOP [47].…”

Aging of the Normal Lung

“…Quan et al (1990) showed a decrease in lung resistance in the first year of life, while dynamic compliance, static compliance, and specific conductance all increased with age. Robinson and Gillespie (1973) did not show any evidence for a change in lung compliance between dogs aged less than 500 days and dogs aged more than 3000 days, although their data were highly variable.…”

“…Data on the changes in lung volume with age in dogs are entirely from in vivo studies (Mauderly, 1974;Robinson and Gillespie, 1973;Quan et al, 1990). All of these studies describe an increase in lung volume with age.…”

“…All of these studies describe an increase in lung volume with age. Quan et al (1990) studied lung volume and function in beagles aged w2e11 months of age. These authors found a linear association between age and FRC over this age range.…”