|| Checking for direct PDF access through Ovid
The aim of our study was to assess the effects of acute and chronic smoking on skin microvascular properties of young healthy subjects.An observational study, using a totally non-invasive approach, employing continuous palmar microvascular flow (laser Doppler) and arterial pressure measurements, to compute estimates of microvascular resistive (Z0) and oscillatory (impedance, i.e. ZC) properties. Measures were obtained at baseline and after iontophoretic administration of acetylcholine (ACh), an endothelium-dependent vasodilator and of sodium nitroprusside (NP), an endothelium-independent vasodilator.A total of 20 healthy male subjects (nine habitual smokers and 11 non-smokers; aged 27 ± 1 and 29 ± 2 years, respectively) in resting conditions and during administration of ACh and of NP (in two different days), before and after smoking one cigarette were evaluated.Smokers showed significant lower baseline Z0 and ZC than non-smokers. In non-smokers, ACh and NP iontophoresis induced a significant decrease of both Z0 and ZC, before and after smoking one cigarette (P< 0.02). Conversely, in smokers, both Z0 and ZC were not affected by ACh iontophoresis before acute smoking, while, after smoking, a significant decrease of both Z0 and ZC (P< 0.02) was detected after ACh challenge. In smokers, both Z0 and ZC were not affected by NP iontophoresis, either before or after smoking a cigarette.Smokers appeared characterized by a complex disruption of peripheral microcirculatory regulation, including inappropriate resting vasodilation, impaired endothelium-dependent and independent vasodilation, paradoxical recovery of endothelium-dependent vasodilation in response to acute smoking.