Characterization of microvessels in the human forehead dermis using intravascular dual perfusion and immunofluorescence staining.

Skin microcirculation provides essential insights in clinical practice. However, the specific characteristics and distribution patterns of dermal microarterioles and microvenules remain insufficiently explored. This study aimed to analyze their structural differences and distribution in the human forehead skin using an innovative intravascular dual perfusion technique combined with immunofluorescence staining to distinguish microvessel types within the dermis. Using two post-mortem cadaver specimens, lead oxide-gelatin perfusion was applied to label microarterioles, and latex was used for microvenules. Tissue sections underwent hematoxylin and eosin and immunofluorescence staining, with cluster of differentiation 31 (CD31) serving as a general vascular marker and monocarboxylate transporter 1 (MCT1) as a venule-specific marker. The analysis revealed significant structural differences between dermal layers: vessels in the deep dermis had larger diameters and thicker walls than those in the superficial layer, while microvessel density was higher in the superficial dermis. These findings demonstrate distinct patterns and significant differences in microvessel distribution between the superficial and deep dermal layers, reflecting their layer-specific functional demands. Furthermore, MCT1 was identified as a specific marker for microvenules, and a novel method combining CD31 and MCT1 immunofluorescent staining was introduced to differentiate dermal microarterioles from microvenules. These results offer valuable implications for surgical planning, skin grafting, and diagnostics related to microcirculation.