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Assessment of replication rates of human keratinocytes in engineered skin substitutes grafted to athymic mice
Author(s) -
Boyce Steven T.,
Rice Rachel K.,
Lynch Kaari A.,
Supp Andrew P.,
Swope Viki B.,
Kagan Richard J.,
Supp Dorothy M.
Publication year - 2012
Publication title -
wound repair and regeneration
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.847
H-Index - 109
eISSN - 1524-475X
pISSN - 1067-1927
DOI - 10.1111/j.1524-475x.2012.00807.x
Subject(s) - keratinocyte , in vivo , epidermis (zoology) , in vitro , basal (medicine) , phenotype , bromodeoxyuridine , mitosis , microbiology and biotechnology , wound healing , biology , skin grafting , cell , stem cell , human skin , andrology , immunology , cell growth , endocrinology , anatomy , medicine , biochemistry , gene , genetics , surgery , insulin
Stable closure of skin wounds with engineered skin substitutes ( ESS ) requires indefinite mitotic capacity to generate the epidermis. To evaluate whether keratinocytes in ESS exhibit the stem cell phenotype of label retention, ESS ( n = 6–9/group) were pulsed with 5‐bromo‐2'‐deoxyuridine (BrdU) in vitro, and after grafting to athymic mice ( n = 3–6/group). Pulse and immediate chase in vitro labeled virtually all basal keratinocytes at day 8, with label uptake decreasing until day 22. Label retention in serial chase decreased more rapidly from day 8 to day 22, with a reorganization of BrdU‐positive cells into clusters. Similarly, serial chase of labeled basal keratinocytes in vivo decreased sharply from day 20 to day 48 after grafting. Label uptake was assessed by immediate chases of basal keratinocytes, and decreased gradually to day 126, while total labeled cells remained relatively unchanged. These results demonstrate differential rates of label uptake and retention in basal keratinocytes of ESS in vitro and in vivo, and a proliferative phenotype with potential for long‐term replication in the absence of hair follicles. Regulation of a proliferative phenotype in keratinocytes of ESS may improve the biological homology of tissue‐engineered skin to natural skin, and contribute to more rapid and stable wound healing.