Dysfunction of the autonomic nervous system as a possible explanation of non-dipping phenomenon in insulin-resistant obese subjects

Carotid atherosclerosis and the association between nocturnal blood pressure dipping and cardiovascular events

The impact of a nondipping blood pressure (BP) pattern, defined as (awake systolic BP - sleep systolic BP)/awake systolic BP < 0.1, on cardiovascular events in populations with different degrees of carotid atherosclerosis is uncertain. The authors hypothesized that a nondipping BP pattern would show differential predictive power for cardiovascular events, including total cardiovascular death, sudden death, nonfatal cardiovascular events, and nonfatal stroke, between populations with and without carotid atherosclerosis. To test this hypothesis, the authors analyzed 493 patients (mean age 67.9 years, 47.5% men) from the J-HOP (Japan Morning Surge-Home Blood Pressure) study for whom ambulatory BP monitoring and carotid intima-media thickness data were available. Twenty-nine cardiovascular events occurred during follow-up (1867 person-years). A nondipping BP pattern was independently associated with cardiovascular events in the population without carotid atherosclerosis, defined as carotid intima-media thickness < 1.1 mm after adjustment for other cardiovascular risk factors including age, sex, diabetes mellitus, chronic kidney disease, and 24-hour systolic BP (hazard ratio, 8.15; 95% confidence interval, 1.76-37.78 [P < .01]). This association was not found in the population with carotid intima-media thickness ≥ 1.1 mm. Therefore, in the hypertensive population without carotid atherosclerosis, physicians should consider ambulatory BP monitoring to determine the nocturnal BP pattern as an alternative approach to assessing cardiovascular events.

Chemoreceptors, baroreceptors, and autonomic deregulation in children with obstructive sleep apnea

Obstructive sleep apnea (OSA) is highly prevalent sleep disorder of breathing in both adults and children that is fraught with substantial cardiovascular morbidities, the latter being attributable to a complex interplay between intermittent hypoxia (IH), episodic hypercapnia, recurrent large intra-thoracic pressure swings, and sleep disruption. Alterations in autonomic nervous system function could underlie the perturbations in cardiovascular, neurocognitive, immune, endocrine and metabolic functions that affect many of the patients suffering from OSA. Although these issues have received substantial attention in adults, the same has thus far failed to occur in children, creating a quasi misperception that children are protected. Here, we provide a critical overview of the evidence supporting the presence of autonomic nervous system (ANS) perturbations in children with OSA, draw some parallel assessments to known mechanisms in rodents and adult humans, particularly, peripheral and central chemoreceptor and baroreceptor pathways, and suggest future research directions.