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Skin Microcirculation (skin + microcirculation)

Distribution by Scientific Domains

Medical Sciences	100%

Selected Abstracts

Orthogonal polarization technique in the assessment of human skin microcirculation

INTERNATIONAL JOURNAL OF DERMATOLOGY, Issue 5 2008
Omar Lupi MD
Background The "gold standard" for the study of the in vivo microcirculation is intravital microscopy. The recently developed method of orthogonal polarization of light [orthogonal polarization spectral (OPS) imaging] allows for the in vivo transcutaneous evaluation of the microcirculation without the need for invasive surgical procedures. Methods The application of polarized light originating from a 100 W halogen tungsten lamp is able to penetrate tissues at a depth of up to 3 mm, and generates reissued light from this depth. The evaluation of this depolarized light, from a deeper origin, may be carried out separately from the light reflected by the more superficial layers of the tissue under study because this light retains photon polarization, whereas the former light undergoes real depolarization. Results The process of validation of the OPS technique, when compared with intravital microscopy, the "gold standard" for the in vivo observation of the microcirculation, has shown that it is as effective and reliable as the gold standard, reaching the same resolution level in the visualization of blood vessels, but without the need for invasive surgical procedures. Conclusions The OPS technique is a very promising tool for dermatologists and researchers, especially in the study of vasculitis, chronic venous insufficiency, and skin tumors. [source]

Acetylcholine-Induced Vasodilation and Reactive Hyperemia Are Not Affected by Acute Cyclo-Oxygenase Inhibition in Human Skin

MICROCIRCULATION, Issue 4 2004
Anne Dalle-Ave
Objective: To examine whether prostaglandins are involved in endothelium-dependent vasodilatory responses of the skin microcirculation. Methods: Twenty-three young male volunteers were studied on 2 different days 1,3 weeks apart. On each experimental day the forearm skin blood flow response to iontophoretically applied acetylcholine (Ach, an endothelium-dependent vasodilator) was determined with laser Doppler imaging following the intravenous administration of either the cyclo-oxygenase inhibitor lysine acetylsalicylate (L-AS), 900 mg, or the oral intake of indomethacin, 75 mg. Acetylcholine was iontophoresed both in presence and in absence of surface anesthesia. In some subjects, the effects of L-AS on skin reactive hyperemia were also assessed. Results: Acute cyclo-oxygenase inhibition with either drug influenced neither the skin blood flow response to 4 different doses of Ach (0.28, 1.4, 7, and 14 mC/cm2) nor reactive hyperemia. The peak vasodilatory response to Ach was significantly increased by skin anesthesia, regardless of whether the subjects received the cyclo-oxygenase inhibitor or not. For example, the mean response (± SD) to the largest dose of Ach (tested in 6 subjects, expressed in perfusion units) were as follows: in absence of anesthesia: L-AS 339 ± 105, placebo 344 ± 68; with anesthesia: L-AS 453 ± 76, placebo 452 ± 65 (p < .01 for effect of anesthesia). Conclusions: These data give no support for a contribution of prostaglandins to acetylcholine-induced vasodilation or to reactive hyperemia in the skin microcirculation. In this vascular bed, local anesthesia seems to amplify acetylcholine-induced vasodilation via a prostaglandin-independent mechanism. [source]

Non-invasive assessment of endothelial function , relation between vasodilatory responses in skin microcirculation and brachial artery

CLINICAL PHYSIOLOGY AND FUNCTIONAL IMAGING, Issue 6 2004
Jimmy Hansell
Summary Objective:, To compare different non-invasive methods for determination of human endothelial function in peripheral circulation. Design:, Observational, cross-sectional study in 39 healthy subjects (21 females, age 17,56 years). Setting:, Vascular research laboratory at university hospital. Methods:, Laser Doppler (LD) flowmetry was used to compare skin microvascular perfusion changes during postocclusive reactive hyperaemia with those induced by iontophoretic administration of acetylcholine (ACh), an endothelial-dependent vasodilator. LD measurements were compared with ultrasonographic measurements of postocclusive flow-mediated dilatation (FMD) in the brachial artery (n = 21). Results:, Local ACh induced a larger and more sustained skin perfusion increase than reactive hyperaemia after 4 min of regional arterial occlusion (P<0·001). A significant correlation was found between the magnitude of ACh-induced vasodilatation and peak reactive hyperaemia, both in absolute (r = 0·62, P<0·001) and relative terms (r = 0·58, P<0·001). A correlation was also found between brachial artery FMD and the magnitude of ACh-induced skin perfusion increase (r = 0·43, P<0·05) but not between FMD and reactive hyperaemia. Conclusion:, Endothelial function, an early marker of cardiovascular risk, can be non-invasively assessed and graded by LD and FMD-measurements and despite inherent differences, both methods do correlate. [source]

The influence of local heating on skin microcirculation in pressure ulcers, monitored by a combined laser Doppler and transcutaneous oxygen tension probe

CLINICAL PHYSIOLOGY AND FUNCTIONAL IMAGING, Issue 6 2000
Vivianne Schubert
In a prospective, controlled study the skin microcirculation and transcutaneous oxygen tension were evaluated in 28 elderly patients (85 ± 0·8 years) with grade 2 and 3 pressure ulcer. Laser Doppler fluxmetry and transcutaneous oxymetry techniques were used together in a combined probe to simultaneously evaluate the influence of heat stress at 44°C, at the same time and in the same area of the ulcer edge. Total skin microcirculation was already increased at rest before heating, and increased even more during a fast and then a more gradually heat-induced hyperaemia response compared with undamaged skin. The increase showed a biphasic manner. On the other hand, the oxygen diffusibility from the capillaries to the skin surface was significantly reduced, compared with undamaged skin. One hypothesis may be that in ageing skin the main part of the increased skin microcirculation in a pressure ulcer were passing through thermoregulatory vessels in subpapillary tissue layers. Interactions between the increased blood flow and metabolic activity at the ulcer edge might be oxygen-consuming, leading to reduced oxygen content passing through the capillaries and contributing to tissue ischaemia. Disturbances of the local skin microcirculation and tissue oxygenation will influence the ulcer healing rate and may affect the healing progress. [source]