Role of nitric oxide in young patients with vasovagal syncope

Abstract

Baseline plasma levels of NOx were significantly lower in HUT(+) patients than in controls. However, since the expected increase in NOx values during HUT-induced syncope was not observed, the possible role of NO in vasovagal hypotension is uncertain.

Are serum nitric oxide metabolites associated with fasting insulin among Iranian adults? (Tehran Lipid and Glucose Study)

“…In the current study, we found an inverse correlation between insulin sensitivity and NO concentration in women, diabetics, and the total population, a finding in line with previous reports (1,9,13). Bøtker et al and Siervo et al found an inverse correlation between insulin sensitivity and NO synthesis (26,27), although, in line with our results in men, Tessari et al (2013), studying 26 subjects, showed that NO synthesis was not correlated with insulin sensitivity (25).…”

“…There is a hypothesis that insulin, besides its stimulatory effects on NO production, also increases NOx removal (1,9,12). Increased circulating NO have been reported in insulin-resistant (IR) subjects (1,6,9,13), although there are some reports that NO synthesis is reduced in the IR state (12,14,15). In both normotensive and hypertensive individuals, insulin-sensitive (IS) subjects had lower NOx levels than IR (6,16).…”

Nitric oxide synthase inhibition restores orthostatic tolerance in young vasovagal syncope patients

“…Increased NO has been reported in postural tachycardia syndrome and VVS,35–37 but results are controversial due to methodological issues 36…”

Endothelial function in vasovagal syncope

“…Some studies have reported significantly higher FMD and higher plasma NO concentration in young people with vasovagal syndrome than in healthy subjects [12,13]. Augmented endothelial function and abnormal vasodilation of peripheral arteries play an important role in the development of VVS in young subjects.…”

“…Patients with VVS showed marked and sustained EID, in the presence of a normal FMD. Children with postural orthostatic tachycardia syndrome have also been shown to have augmented FMD and abnormal vascular endothelial function, which may play an important role in syncope induction [4,[12][13][14]. Studies by Wnuk and colleagues in our department indicated that increased FMD or EID, associated with abnormal endothelial function in the regulation of vascular wall tension after tilting of patients with VVS, are strong predictors of reflex syncope (submitted).…”