Bull R, Ansell G, Stanton A W, Levick J R, Mortimer P S
Department of Physiological Medicine, St. George's Hospital Medical School, London, UK.
Int J Microcirc Clin Exp. 1995 Mar-Apr;15(2):65-74. doi: 10.1159/000178952.
Skin just proximal to the medial malleolus ('gaiter' zone) is the usual site for venous ulceration in later life, whereas shin and dorsum of the foot are generally unaffected. We studied the microcirculation of these regions in 6 healthy young adults to see whether any premorbid, constitutional differences in microvascular physiology or anatomy exist between local leg sites even in normal subjects. Capillary density was assessed by capillaroscopy (native and fluorescein) and local flow by laser Doppler fluxmetry, in supine and upright positions and during reactive hyperaemia. Supine capillary densities in supramedial malleolar skin (SMMS) averaged 31038 mm(-2) (fluorescein and native count means, respectively) and was not statistically significantly different from those in the dorsum of the foot (36.0-36.2 mm(-2) or shin 30-51 mm(-2)). Dependency did not alter the counts significantly, but the fluorescein transport time from antecubital vein to capillary increased by 16-69% (SMMS 40%). In the supine position, red cell flux in SMMS was only 42-43% of the flux in skin over the shin and dorsum of the foot (p<0.04, 2-way analysis of variance) and cumulative reactive hyperaemia in SMMS was also less marked. Basal flux and reactive hyperaemia at all sites fell to closely similar levels in dependency (veni-arteriolar response). In relative terms, however, the posturally induced vasoconstriction was weaker in SMMS (flux reduction by 29% of supine value) than at other sites (reductions 61-61% of supine value). The results showed that even in young healthy legs the cutaneous microcirculation is not physiologically homogeneous, raising the possibility that constitutional factors might influence the siting of overt pathology if chronic venous insufficiency develops in later life.
内踝近端的皮肤（“绑腿”区）是晚年静脉溃疡的常见部位，而小腿前部和足背通常不受影响。我们研究了6名健康年轻成年人这些区域的微循环，以确定即使在正常受试者中，局部腿部位置之间在微血管生理或解剖学上是否存在任何病前体质差异。通过毛细血管镜检查（自然状态和荧光素状态）评估毛细血管密度，并通过激光多普勒血流仪在仰卧位和直立位以及反应性充血期间评估局部血流。内踝上内侧皮肤（SMMS）的仰卧位毛细血管密度平均为31.0±3.8mm⁻²（分别为荧光素和自然状态计数的平均值），与足背（36.0 - 36.2mm⁻²）或小腿前部（30 - 51mm⁻²）相比，差异无统计学意义。体位改变对计数影响不显著，但荧光素从前臂静脉到毛细血管的运输时间增加了16% - 69%（SMMS为40%）。在仰卧位时，SMMS中的红细胞通量仅为小腿前部和足背皮肤通量的42% - 43%（p<0.04，双向方差分析），SMMS中的累积反应性充血也不太明显。在体位改变时（静脉 - 小动脉反应），所有部位的基础通量和反应性充血均降至非常相似的水平。然而，相对而言，SMMS中体位诱导的血管收缩较弱（通量降低至仰卧位值的29%），而其他部位（降低至仰卧位值的61% - 69%）。结果表明，即使在年轻健康的腿部，皮肤微循环在生理上也不均匀，这增加了如果晚年发生慢性静脉功能不全，体质因素可能影响明显病理部位的可能性。
