A rapid fabricated living dermal equivalent for skin tissue engineering: an in vivo evaluation in an acute wound model.

The encapsulation of both cells and a surgical mesh in a polymerizing collagen hydrogel followed by mechanical compression, after polymerization, results in the rapid formation of a living dermal equivalent (LDE) with physical properties suitable for in vivo application. It was found in the current study that the LDE supported the attachment, growth, and differentiation of keratinocytes, allowing for the formation of living skin equivalents (LSEs) with a monolayer epidermis (LSE-M) and a stratified epidermis (LSE-S). The utility of the LDE for the fabrication of living wound dressings was further evaluated by testing the safety and efficacy of the LSE-M and LSE-S in a lapine model of an acute full-thickness skin defect. It was found that the LSE-S significantly stimulated blood vessel formation and accelerated epidermal wound closure compared with controls. The LSE-M showed similar trends but these were not significant. These findings indicate the clinical usefulness of the LDE in the treatment of acute and possibly chronic wounds, such as venous and diabetic ulcerations. The 1-h fabrication time of the LDE is a significant reduction compared with that of dermal components of current FDA-approved dressings, such as Dermagraft, Apligraf, and OrCel, which require days to weeks of in vitro culture. It is therefore proposed that the presented method could reduce the high cost associated with the production of living, tissue-engineered dressings.

High-density collagen gel tubes as a matrix for primary human bladder smooth muscle cells.

Tissue-engineered grafts for the urinary tract are being investigated for the potential treatment of several urologic diseases. These grafts, predominantly tubular-shaped, usually require in vitro culture prior to implantation to allow cell engraftment on initially cell-free scaffolds. We have developed a method to produce tubular-shaped collagen scaffolds based on plastic compression. Our approach produces a ready cell-seeded graft that does not need further in vitro culture prior to implantation. The tubular collagen scaffolds were in particular investigated for their structural, mechanical and biological properties. The resulting construct showed an especially high collagen density, and was characterized by favorable mechanical properties assessed by axial extension and radial dilation. Young modulus in particular was greater than non-compressed collagen tubes. Seeding densities affected proliferation rate of primary human bladder smooth muscle cells. An optimal seeding density of 10(6) cells per construct resulted in a 25-fold increase in Alamar blue-based fluorescence after 2 wk in culture. These high-density collagen gel tubes, ready seeded with smooth muscle cells could be further seeded with urothelial cells, drastically shortening the production time of graft for urinary tract regeneration.

A classification system of radial polydactyly: inclusion of triphalangeal thumb and triplication.

PURPOSE: Radial polydactyly is a congenital anomaly with a wide range of manifestations. Current classifications do not have the capacity to classify all different types of radial polydactyly when combined with triphalangeal components. The objective of this study was to test an adjusted classification and nomenclature that allows classification of triphalangeal components and triplication in radial polydactyly. METHODS: Patients from 1993 to 2006 with radial polydactyly (N = 104), a total of 121 affected hands, were identified from the hospital database. All x-rays were carefully examined and classified according to the existing classifications for radial polydactyly and a modified classification. In the modified nomenclature, Wassel's level of duplication is preserved. Type VII and VIII are assigned for partial or complete duplication of the carpal bones according to Buck-Gramcko. Triplication and triphalangeal components can be assigned to each type of radial polydactyly by suffixes. Symphalangism, deviation, and hypoplasia can also be classified. Triplication on different levels of the thumb is classified by determining and including the different types of the original Wassel classification. RESULTS: Eighteen thumbs could not be classified according to existing classifications for radial polydactyly with triphalangeal components or triplication. Using the proposed classification, all patients could be classified. CONCLUSIONS: We propose a modified classification that is a practical and utilitarian scheme for nomenclature of radial polydactyly and that may assist comparison of treatment outcomes and individual cases. TYPE OF STUDY/LEVEL OF EVIDENCE: Diagnostic II.