title: Analysis of blood and lymph vascularization patterns in tissue-engineered human dermo-epidermal skin analogs of different pigmentation.
abstract: OBJECTIVE
  Bioengineered dermo-epidermal skin analogs containing melanocytes represent a promising approach to cover large skin defects including restoration of the patient's own skin color. So far, little is known about the development of blood and lymphatic vessels in pigmented skin analogs after transplantation. In this experimental study, we analyzed the advancement and differences of host blood and lymphatic vessel ingrowth into light- and dark-pigmented human tissue-engineered skin analogs in a rat model.
  
  
  METHODS
  Keratinocytes, melanocytes, and fibroblasts from light- and dark-pigmented skin biopsies were isolated, cultured, and expanded. For each donor, melanocytes and keratinocytes were seeded in ratios of 1:1, 1:5, and 1:10 onto fibroblast-containing collagen gels. The skin analogs were subsequently transplanted onto full-thickness wounds of immuno-incompetent rats and quantitatively analyzed for vascular and lymphatic vessel density after 8 and 15 weeks.
  
  
  RESULTS
  The skin analogs revealed a significant difference in vascularization patterns between light- and dark-pigmented constructs after 8 weeks, with a higher amount of blood vessels in light compared to dark skin. In contrast, no obvious difference could be detected within the light- and dark-pigmented group when varying melanocyte/keratinocyte ratios were used. However, after 15 weeks, the aforementioned difference in blood vessel density between light and dark constructs could no longer be detected. Regarding lymphatic vessels, light and dark analogs showed similar vessel density after 8 and 15 weeks, while there were generally less lymphatic than blood vessels.
  
  
  CONCLUSIONS
  These data suggest that, at least during early skin maturation, keratinocytes, melanocytes, and fibroblasts from different skin color types used to construct pigmented dermo-epidermal skin analogs have distinct influences on the host tissue after transplantation. We speculate that different VEGF expression patterns might be involved in this disparate revascularization pattern observed.
authors.affiliation: University Children's Hospital Zurich, Tissue Biology Research Unit, Zurich, Switzerland.
authors.forename: Agnieszka S
authors.initials: AS
authors.lastname: Klar
authors.forename: Sophie
authors.initials: S
authors.lastname: Böttcher-Haberzeth
authors.forename: Thomas
authors.initials: T
authors.lastname: Biedermann
authors.forename: Clemens
authors.initials: C
authors.lastname: Schiestl
authors.forename: Ernst
authors.initials: E
authors.lastname: Reichmann
authors.forename: Martin
authors.initials: M
authors.lastname: Meuli
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D020405:Dermis / Q000098:blood supply; D004817:Epidermis; D005260:Female; D005347:Fibroblasts / Q000637:transplantation; D052816:Foreskin; D006801:Humans; D015603:Keratinocytes / Q000637:transplantation; D042601:Lymphatic Vessels / Q000098:blood supply*; D008297:Male; D008544:Melanocytes / Q000637:transplantation; D023421:Models, Animal; D051381:Rats; D012867:Skin / Q000098:blood supply*; D012880:Skin Pigmentation / Q000502:physiology*; D016038:Skin Transplantation / Q000379:methods*; D023822:Tissue Engineering / Q000379:methods*; D014947:Wounds and Injuries / Q000601:surgery