A human skin equivalent burn model to study the effect of a nanocrystalline silver dressing on wound healing.

In this study, a deep burn wound model was established using a 3D human skin equivalent (HSE) model and this was compared to native skin. HSEs were constructed from dermis derived from abdominoplasty/breast surgery and this dermal template was seeded with primary keratinocytes and fibroblasts. The HSE model was structurally similar to native skin with a stratified and differentiated epidermis. A contact burn (60 °C, 80 °C, 90 °C) was applied with a modified soldering iron and wounds were observed at day 1 and 7 after burn. The HSEs demonstrated re-growth with keratinocyte proliferation and formation of a neo-epidermis after burn injury, whereas the ex vivo native skin did not. To assess the suitability of the 3D HSE model for penetration and toxicity studies, a nanocrystalline silver dressing was applied to the model for 7 days, with and without burn injury. The effect of silver on skin re-growth and its penetration and subcellular localization was assessed in HSEs histologically and with laser ablation-inductively coupled plasma mass spectrometry (LA-ICPMS). The silver treatment delayed or reduced skin re-growth, and silver particles were detected on the top of the epidermis, and within the papillary dermis. This novel in vitro 3D multicellular deep burn wound model is effective for studying the pathology and treatment of burn wound injury and is suitable for penetration and toxicity studies of wound healing treatments.

A systematic review on cell-seeded tissue engineering of penile corpora.

Tissue engineering of corporal tissue is a new development in otherwise untreatable erectile dysfunction and in urethral reconstructions to treat hypospadias or severe urethral stricture disease. Multiple complications can arise with the current treatments, whereas engineered tissue, if well vascularized and existing of autologous cells, may lead to better results. The aim of this review was to provide an overview of literature on cell-seeded-based tissue engineering of corporal penile tissue. A literature search was performed following the PRISMA guidelines. Papers describing cell-seeded tissue engineering of corporal tissue were included. Studies using different techniques, such as intracavernous injection were excluded. Fifteen articles were included in the review. Twelve of these studies described engineering of the corpus cavernosum in animal models. Two articles were found on engineering of animal corpus spongiosum and one article on engineering of the human glans. Both synthetic scaffolds and biological scaffolds were used. The advantage of a biological, acellular scaffold was that the native, complex architecture of corporal tissue was maintained. Most studies used endothelial and smooth muscle cells from corporal origin, but stem cells were also investigated. Furthermore, dynamic culturing achieved an improved cell content and functionality. This review has summarized the developments in tissue engineering of corpus cavernosum and spongiosum tissue. Functional tissue has been developed in animal studies with the use of seeded cells on scaffolds. This knowledge will form a basis for the development of tissue engineering of corporal tissue for clinical applications.

Measurement of thromboxane and prostacyclin in valvulotomized human saphenous veins.

The present study was done to determine the effect of the modified Hall valvulotome technique on endothelial injury by measuring TxB2 and 6-keto PGF1alpha, the stable metabolites of thromboxane and prostacyclin, respectively. It was hypothesized that increased levels of these cyclooxygenase products would be an excellent indicator of vascular endothelial injury in the presence of the modified Hall valvulotome. Eight segments of human distal saphenous veins were obtained, each measuring approximately 4 cm in length, with diameters of approximately 2 to 3 mm. From these original vein segments, two groups of smaller vein segments were examined, with each group consisting of eight segments, each segment measuring 2 cm in length. The first group of vein segments was designated as the control group, and the second group of vessels had a modified Hall valvulotome (2.5 mm size) inserted into each segment to simulate valvulotomy. After this procedure, all vein segments were analyzed for levels of thromboxane and prostacyclin by a standard radioimmunoassay procedure. Results from the present study indicate that the modified Hall valvulotome technique in human saphenous veins does not significantly increase the levels of the cyclooxygenase metabolites thromboxane and prostacyclin relative to control conditions. However, the ratio of TxB2 formation 6-keto PGF1alpha production was increased in the valvulotomized vessel segments, indicating possible platelet release of thromboxane. Therefore, even though there was increased thromboxane production relative to prostacyclin levels in the modified Hall valvulotome technique, it still appears that this type of valvulotomy is relatively noninsulting to the endothelial cell lining.