Nocturnal thoracoabdominal asynchrony in house dust mite-sensitive nonhuman primates

XiaoJia Wang, Shaun Reece, Stephen Olmstead, Robert L Wardle, Michael R Van Scott

Department of Physiology, East Carolina University, Greenville, North Carolina, USA

Abstract: Nocturnal bronchoconstriction is a common symptom of asthma in humans, but is poorly documented in animal models. Thoracoabdominal asynchrony (TAA) is a noninvasive clinical indication of airway obstruction. In this study, respiratory inductive plethysmography (RIP) was used to document nocturnal TAA in house dust mite (HDM)-sensitive Cynomolgus macaques. Dynamic compliance (C_dyn) and lung resistance (R_L) measured in anesthetized ­animals at rest and following exposure to HDM allergen, methacholine, and albuterol were highly ­correlated with three RIP parameters associated with TAA, ie, phase angle of the rib cage and abdomen waveforms (PhAng), baseline effort phase relation (eBPRL) and effort phase relation (ePhRL). Twenty-one allergic subjects were challenged with HDM early in the morning, and eBPRL and ePhRL were monitored for 20 hours after provocation. Fifteen of the allergic subjects exhibited gradual increases in eBPRL and ePhRL between midnight and 6 am, with peak activity at 4 am. However, as in humans, this nocturnal response was highly variable both between subjects and within subjects over time. The results document that TAA in this nonhuman primate model of asthma is highly correlated with C_dyn and R_L, and demonstrate that animals exhibiting acute responses to allergen exposure during the day also exhibit nocturnal TAA.

Keywords: nocturnal asthma, late phase asthmatic response, respiratory inductive plethysmography