Age protects from harmful effects produced by chronic intermittent hypoxia.
J Physiol
; 594(6): 1773-90, 2016 Mar 15.
Article
em En
| MEDLINE
| ID: mdl-26752660
ABSTRACT
Obstructive sleep apnoea (OSA) affects an estimated 37% of the adult population, the frequency doubling at ages >6065 years. As it evolves, OSA becomes frequently associated with cardiovascular, metabolic and neuropsychiatric pathologies defining OSA syndrome (OSAS). Exposing experimental animals to chronic intermittent hypoxia (CIH) can be used as a model of the recurrent hypoxic and O2 desaturation patterns observed in OSA patients. CIH is an important OSA event triggering associated pathologies; CIH induces carotid body (CB)-driven exaggerated sympathetic tone and overproduction of reactive oxygen species, related to the pathogenic mechanisms of associated pathologies observed in OSAS. Aiming to discover why OSAS is clinically less conspicuous in aged patients, the present study compares CIH effects in young (34 months) and aged (2224 months) rats. To define potential distinctive patterns of these pathogenic mechanisms, mean arterial blood pressure as the final CIH outcome was measured. In young rats, CIH augmented CB sensory responses to hypoxia, decreased hypoxic ventilation and augmented sympathetic activity (plasma catecholamine levels and renal artery content and synthesis rate). An increased brainstem integration of CB sensory input as a trigger of sympathetic activity is suggested. CIH also caused an oxidative status decreasing aconitase/fumarase ratio and superoxide dismutase activity. In aged animals, CIH minimally affected CB responses, ventilation and sympathetic-related parameters leaving redox status unaltered. In young animals, CIH caused hypertension and in aged animals, whose baseline blood pressure was augmented, CIH did not augment it further. Plausible mechanisms of the differences and potential significance of these findings for the diagnosis and therapy of OSAS are discussed.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Envelhecimento
/
Corpo Carotídeo
/
Apneia Obstrutiva do Sono
/
Hipóxia
Tipo de estudo:
Etiology_studies
/
Prognostic_studies
Limite:
Animals
Idioma:
En
Ano de publicação:
2016
Tipo de documento:
Article