Study of microvascular structure in keloid and hypertrophic scars: density of microvessels and the efficacy of three-dimensional vascular imaging.

We have investigated the blood vessels in keloids and hypertrophic scars, both morphologically and statistically. We also tried to construct three-dimensional images of blood vessels in a keloid and hypertrophic scar to clarify the vascular patterns. Keloids (n = 16) and hypertrophic scars (n = 12) were stained with haematoxylin and eosin, and immunostained with anti-CD31 antibody. The capillary density (number/1.0 mm(2)) and length of the major and minor axes were measured, and the major:minor axis ratio was calculated. Eighty serial sections were prepared from the preparations. Using image preparation software (Realia, INTAGE), the 80 input images were superimposed to construct a three-dimensional image of blood vessels in the tissue. We initially succeeded in constructing three-dimensional images of blood vessels in a keloid and hypertrophic scar. By statistical analysis of the vascular density and morphology, we clarified that there were fewer capillaries in keloids than in hypertrophic scars (p < 0.01), and that the vascular lumen was flattened. Capillaries in the central region of keloids tended to flat, compared with those in the marginal region. Three-dimensional images suggested that there was no microvascular communication in keloids; there was also an inadequate blood supply in keloid tissue. These findings may be a result of the growth of collagen and fibroblasts with keloid maturation.