Transplantation of autologous epidermal melanocyte-keratinocyte cells suspension for cell therapy of vitiligo: A clinical evaluation and biometric assessment.

INTRODUCTION: Among several surgical treatments, the use of transplantation of epidermal cultured melanocytes or melanocytes-keratinocytes cell suspension has gained many researchers and dermatologists' attention as a new technique for the treatment of vitiligo. The present study aimed to transplant autologous epidermal melanocytes-keratinocytes cell suspension for the treatment of vitiligo. METHODS: In this study, 15 volunteer patients aged between 18 and 45 years old were studied. The autologous melanocytes-keratinocytes cell suspension was then transplanted to the region after dermabrasion. The included patients were evaluated by VisioFace, MPA9, and Skin Scanner-DUB once before and 1, 2, and 6 months after the transplantation, while the extents of stainability and changes in the transplanted region were recorded. RESULTS: The color contrast between the lesion and normal skin significantly decreased after 1, 2, and 6 months of the melanocytes transplantation compared with the pre-procedure (13.8 ± 0.45 before vs. 12.9 ± 0.43, 12.2 ± 0.45, and 10.2 ± 0.34 at months 1, 2, and 6, p < 0.001). Furthermore, melanin index significantly increased six months after cell transplantation compared to the pretreatment (168.3 ± 4.22 vs. 130.5 ± 3.98, p < 0.001). CONCLUSION: Transplantation of melanocytes cells with dermabrasion can be effective on vitiligo improvement, so it is recommended.

Noninvasive Optical Assessment of Implanted Engineered Tissues Correlates with Cytokine Secretion.

Fluorescence lifetime sensing has been shown to noninvasively characterize the preimplantation health and viability of engineered tissue constructs. However, current practices to monitor postimplantation construct integration are either qualitative (visual assessment) or destructive (tissue histology). We employed label-free fluorescence lifetime spectroscopy for quantitative, noninvasive optical assessment of engineered tissue constructs that were implanted into a murine model. The portable system was designed to be suitable for intravital measurements and included a handheld probe to precisely and rapidly acquire data at multiple sites per construct. Our model tissue constructs were manufactured from primary human cells to simulate patient variability based on a standard protocol, and half of the manufactured constructs were stressed to create a range of health states. Secreted amounts of three cytokines that relate to cellular viability were measured in vitro to assess preimplantation construct health: interleukin-8 (IL-8), human ß-defensin 1 (hBD-1), and vascular endothelial growth factor (VEGF). Preimplantation cytokine secretion ranged from 1.5 to 33.5 pg/mL for IL-8, from 3.4 to 195.0 pg/mL for hBD-1, and from 0.1 to 154.3 pg/mL for VEGF. In vivo optical sensing assessed constructs at 1 and 3 weeks postimplantation. We found that at 1 week postimplantation, in vivo optical parameters correlated with in vitro preimplantation secretion levels of all three cytokines (p < 0.05). This correlation was not observed in optical measurements at 3 weeks postimplantation when histology showed that the constructs had re-epithelialized, independent of preimplantation health state, supporting the lack of a correlation. These results suggest that clinical optical diagnostic tools based on label-free fluorescence lifetime sensing of endogenous tissue fluorophores could noninvasively monitor postimplantation integration of engineered tissues.

Assessment of replication rates of human keratinocytes in engineered skin substitutes grafted to athymic mice.

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.

Quality of life evaluation in wounds: validation of the Freiburg Life Quality Assessment-wound module, a disease-specific instrument.

Many patients with chronic wounds suffer not only directly from their wounds but also from high financial, social and psychological impairments, significantly reducing their quality of life. In order to provide an instrument both applicable to different patient populations and sensitive to areas of impact specific to certain skin diseases, the modular instrument 'Freiburg Life Quality Assessment' has been developed. Each disease-specific version of the instrument consists of a core module of generic items and items specific for a distinct skin disease. Objective of the study was to assess reliability, sensitivity to change, and validity of the module for chronic ulcers. The instrument was implemented in a longitudinal observational study on vacuum-seal therapy (n = 175), in a cross-sectional observational study involving patients with chronic leg ulcers (n = 384) and in a randomised clinical trial on keratinocyte transplantation (n = 198). The instrument showed good internal consistency (Cronbach's alpha ≥0·85). There were minor floor effects ≤4·3%, but no ceiling effects. Retest-reliability and convergent validity with the EuroQol quality of life questionnaire (EQ-5D) (visual analogue scale) were satisfactory. Change scores correlated with change in other quality-of-life instruments (r = 0·59-0·61), but not with change in wound status.

Assessment of optimal transduction of primary human skin keratinocytes by viral vectors.

BACKGROUND: Genetically modified keratinocytes generate transplantable self-renewing epithelia suitable for delivery of therapeutic polypeptides. However, the variety of viral vectors and experimental conditions currently used make fragmented or contradictory the information on the transduction efficiency of the human primary keratinocytes. To compare the suitability of the most currently used viral vectors for efficient gene transfer to human keratinocytes, we have performed a comparative study using a panel of recombinant constructs. METHODS: For each vector, the transduction efficiency and the persistence of the transgene expression were quantified by fluorescence microscopy and flow cytometry analysis of the infected cells. RESULTS: We show that: (1) canine and human adenoviral vectors achieve a highly efficient but transient transduction of both primary and immortalized keratinocytes; (2) the adenovirus-associated virus (AAV) vectors transduce immortalized keratinocytes, albeit with a short-lived gene expression (<4 days), but fail to infect primary keratinocytes; and (3) under appropriate conditions, the oncoretroviral and lentiviral vectors can permanently transduce up to 100% of primary keratinocytes, but the highly clonogenic keratinocytes are more efficiently targeted by lentiviral vectors. CONCLUSIONS: Therefore, AAV vectors are unsuitable to transduce primary keratinocytes, while human and canine adenoviral vectors appears to be appropriate to achieve short-term delivery of therapeutic products. Recombinant retroviruses provide sustained expression of the transgene, but the lentiviral vectors are the most suitable for ex vivo gene therapy because of their ability to transduce clonogenic primary keratinocytes.

Quantitative assessment of cell viability and apoptosis in cultured epidermal autografts: application to burn therapy.

Cultured epidermal autografts (CEA) have been used in the treatment of burns for almost two decades but the clinical results are still inconsistent. In a group of 37 patients with extensive burn wounds admitted to the University Hospital of Lausanne, CEA take ranged between 10 and 100% with a mean of 65%. To investigate CEA efficacy in burns, twelve CEA preparations were tested for their biological properties with particular emphasis on the balance between cell viability and apoptosis. Apoptosis was evaluated by in situ end-labeling (TUNEL), detection of DNA fragments in CEA extracts and analysis of caspase-3 activity. All CEA samples displayed a high cell viability (> 90%) and a low apoptosis rate (< 6%). However, several biological parameters including the activity of transglutaminase showed wide interindividual variability suggesting that CEA therapeutic efficacy could be partly determined by intrinsic biological factors.

Organotypical engineering of differentiated composite-skin equivalents of human keratinocytes in a collagen-GAG matrix (INTEGRA Artificial Skin) in a perfusion culture system.

BACKGROUND: The production of autologous composite skin equivalents for the treatment of full-thickness skin defects in burns is time consuming and costly because of laboratory procedures which have to be performed manually. In the present study keratinocytes were seeded into INTEGRA Artificial Skin and placed in a perfusion culture system in order to evaluate the possibility of producing composite grafts in an automated system with the aim of establishing a cost-effective method of industrial production. METHODS: Composite grafts of INTEGRA and human keratinocytes were raised in perfusion culture and grafted onto athymic mice to evaluate their potential to reconstitute a full-thickness skin substitute in vivo compared to grafts from standard stagnant cultures. RESULTS: Cultured composites from perfusion cultures showed no significant histological differences compared to those from stagnant cultures; however, a tendency of improved cell growth and a more surface-oriented localization was observed. Cell proliferation and surface-bound differentiation were not impaired by the use of carbonate-independent buffering (HEPES), which is necessary for perfusion culture. The composite grafts from perfusion culture exhibited identical wound adherence and complete healing and histologically represented a multi-layered, keratinizing human epidermis. CONCLUSION: Engineering of differentiated composite skin equivalents is possible in a perfusion culture system, which offers technical and procedural and possibly even biological advantages compared to standard stagnant culture methods. The development of automated perfusion culture systems for the production of composite grafts in sizes required clinically (scale-up) will be the next step in the cost-effective engineering of large-scale composite skin equivalents.

[Production of autologous keratinocytes for therapeutic purposes within a pharmaceutical company]. / Production de kératinocytes autologues à buts thérapeutiques au sein d'un établissement pharmaceutique.

Because biotechnologies are growing and are becoming key players in the pharmaceutical industry scene, Genévrier Laboratories inaugurated in January 1998, a new department especially designed for the production of cultured cells as therapeutic agents. Meeting clinician therapeutic needs by providing autologous keratinocytes and chondrocytes in the near future, represents the primary aim of the Biotechnology department. Concrete cell-based products are already being used for the treatment of burns and cutaneous chronic wounds such as the EPIBASE graft, which corresponds to an epidermis sheet composed of cultured autologous keratinocytes.

Assessment with the dermal torque meter of skin pliability after treatment of burns with cultured skin substitutes.

The assessment of visco-elastic (V-E) properties in cutaneous scars is critical to reduction of impairment and restoration of function after grafting of excised burns. Cultured skin substitutes (CSS) that consist of autologous keratinocytes and fibroblasts attached to biopolymer substrates are alternatives for permanent closure of excised, full-thickness burns, but assessment of scarring has been subjective. V-E properties of CSS were measured with a Dia-Stron Dermal Torque Meter (DTM 310, Dia-Stron, Ltd, Broomall, Pa), which applies a constant torque (10 mNm) for a fixed interval (10 seconds) and measures rotational deformation and recovery. Parameters of skin deformation were measured in patients (n = 10) after grafting of CSS or meshed skin autograft. Native human skin (NHS) of healthy volunteers (n = 13) served as the control. Skin healed after treatment with CSS or autograft was evaluated for 1 year or longer after grafting. Elastic stretch (Ue), viscous stretch (Uv), total extensibility (Uf), elastic recovery (Ur), total recovery (Ua), and residual plasticity (R) were measured as degrees of rotation, were tested for significance (P < .05) by Student t test comparisons between treatment groups and controls, and were subjected to regression analysis. Assessment of burn scar with the Dermal Torque Meter detected time-dependent increases of all individual parameters of V-E properties for both CSS and autograft during the first year after grafting. At 1 year or later, no statistical differences were found between CSS and autograft for individual parameters, but Ue and Ur for autograft were significantly lower than for NHS. At 1 year or longer, autograft was significantly different from CSS or NHS, with a greater ratio of Uv to Ue, and both graft types had a lower ratio of Ur to Uf than NHS had. These results suggest that instrumental measurement of scar pliability may increase objectivity in assessment of patient recovery and establish an absolute scale for quantitative analysis of V-E properties in skin after grafting of conventional or alternative skin substitutes.

A simple human dermal model for assessment of in vitro attachment efficiency of stored cultured epithelial autografts.

This study investigated the effect of short-term storage on the viability and in vitro attachment efficiency of cultured epithelial autograft sheets. Four storage protocols were investigated: overnight at 37 degrees C in keratinocyte culture medium, overnight at 4 degrees C in phosphate-buffered saline solution, overnight at -80 degrees C in cryopreservation medium (containing 10% dimethyl sulphoxide), and 1 week at -80 degrees C in cryopreservation medium. Viability was assessed before and after storage by the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay. All the storage conditions significantly reduced viability compared with fresh sheets, and no significant decrease was seen when the sheets stored under the different protocols were compared with each other. The best viability obtained was 60% of that of the fresh sheets. The in vitro viability of these stored sheets was then compared with that of the fresh sheets by culturing them on deepidermized acellular allodermis and assessing the composites formed by light microscopy and the MTT assay. The fresh sheets attached and formed a histologically demonstrable composite with the dermal substrate, whereas none of the stored sheets formed demonstrable composites. The MTT assay demonstrated that composites formed with the stored sheets had less than 10% viability compared with composites formed with fresh sheets. It is concluded that under the conditions of storage examined, the viability of cultured epithelial autograft sheets was significantly reduced, but up to 60% of viability could be retained in some cases. However, the subsequent in vitro attachment and proliferation of such preserved sheets on allogeneic deepidermized dermis was poor compared with that of fresh cultured epithelial autograft sheets.

Skin replacements. The biotechnological quest for optimal wound closure.

Extensive skin loss from a variety of conditions is associated with significant functional morbidity and loss of life. In many patients, a limited number of donor sites available for harvesting autologous split-thickness skin grafts prevents early, effective, and permanent wound closure. In the past 25 years, significant biotechnological advancements have been made in defining the criteria and manufacturing ingredients in materials that could serve as skin replacements for permanent wound closure. The optimal skin replacement should have the functional and cosmetic properties of the dermis and the epidermis. It should provide rapid, functional wound coverage and barrier protection to microorganisms, normalize fluid flux and hypermetabolism, and provide long-term stability without contraction or hypertrophic scarring. In addition, the optimal skin replacement should be nontoxic, easily stored and used, and relatively cost-effective. This report will discuss the two major skin replacement designs available today, cultured keratinocyte grafts and bioartificial bilaminate systems, outline the advantages and disadvantages of each material, report the results of clinical trials for each, and speculate on the potential for each material to serve as a practical skin replacement.

Wound closure and outcome in extensively burned patients treated with cultured autologous keratinocytes.

Cultured autologous keratinocytes (CAK) have been heralded as a means to achieve more rapid closure of massive burn wounds. Despite the claimed benefits of this technology, we have failed to identify its positive impact on wound closure in extensively burned patients. Sixteen patients with a mean age of 29.7 years (range, 10-56 years) and a mean total body surface area burn of 68.2% (range, 42%-85%) underwent 22 applications of CAK supplied by a private laboratory. The keratinocyte grafts were applied to a mean of 15.9% of the body surface area (range, 4%-59%) at an average cost per patient of $43,705 (range, $9,800 to $161,000). The mean body surface area of definitive wound coverage by these grafts was 4.7% (range, 0%-18.6%). The mean length of hospitalization was 132 days (range, 50-275 days). The observed mortality was 12.5% (two patients). Our experience with this wound care approach has been assessed with respect to the extent of burn, the level of wound excision, and the site of CAK application.

Assessment of disinfectant topical agents in keratinocyte cell culture grafting technique in severely burned patients.

On the basis of previous experiences and of international literature data the authors emphasize the importance of making a "targeted" choice of the topical disinfectant in the therapy of burn wound infections. The objective of the investigation is to reach the highest rate of take of the autologous keratinocyte cultures in burn wounds.