A new approach to the production of a biovital skin graft based on human acellular dermal matrix produced in-house, in vitro revitalized internally by human fibroblasts and keratinocytes on the surface

An organotypic model of oral mucosa cells for the biological assessment of 3D printed resins for interim restorations

STATEMENT OF PROBLEM

Three-dimensionally (3D) printed resins have become popular as a new class of materials for making interim restorations. However, little is known about how the fabrication parameters can influence biological compatibility with oral tissues.

PURPOSE

The purpose of this in vitro study was to evaluate the effect of the postpolymerization time on the cytotoxicity of resins for printing interim restorations by using a 3D organotypic model of the oral mucosa.

MATERIAL AND METHODS

Cylindrical specimens were prepared with conventional acrylic resin (AR), computer-aided design and computer-aided manufacture (CAD-CAM) resin (CC), composite resin (CR), and 2 resins for 3D printing (3DP) marketed as being biocompatible. The 3DPs were submitted to postpolymerization in an ultraviolet (UV) light chamber for 1, 10, or 20 minutes (90 W, 405 nm). Standard specimens of the materials were incubated for 1, 3, and 7 days in close contact with an organotypic model of keratinocytes (NOK-Si) in coculture with gingival fibroblasts (HGF) in a 3D collagen matrix, or directly with 3D HGF cultures. Then, the viability (Live/Dead n=2) and metabolism (Alamar Blue n=6) of the cells were assessed. Spectral scanning of the culture medium was performed to detect released components (n=6) and assessed statistically with ANOVA and the Tukey post hoc test (α=.05).

RESULTS

Severe reduction of metabolism (>70%) and viability of keratinocytes occurred for 3DP resin postpolymerized for 1 minute in all periods of analysis in a time-dependent manner. The decrease in cell metabolism and viability was moderate for the 3D culture of HGFs in both experimental models, correlated with the intense presence of resin components in the culture medium. The resins postpolymerized for 10 and 20 minutes promoted a mild-moderate cytotoxic effect in the period of 1 day, similar to AR. However, recovery of cell viability occurred at the 7-day incubation period. The 3DP resins submitted to postpolymerization for 20 minutes showed a pattern similar to that of CR and CC at the end of the experiment.

CONCLUSIONS

The cytotoxic potential of the tested 3DP resins on oral mucosa cells was influenced by postprinting processing, which seemed to have been related with the quantity of residual components leached.

The urgent need to achieve an optimal strategic stock of human allogeneic skin graft materials in case of a mass disaster in Poland

A burn is a sudden injury which immediate or long-term consequences may be life-threatening for the patient. A mass disaster event may involve large numbers of severely burned patients. Patients of this type typically have a limited area of healthy, unburned skin from which an autologous split thickness skin graft could be collected. In a clinical situation of this type, it is necessary to use a particular skin substitute. Non-viable allogeneic human skin graft materials might be considered as the most suitable skin substitutes in the treatment of such patients. At present, Poland does not have a sufficient supply of human allogeneic skin graft materials to meet the needs arising from a sudden and unforeseen mass disaster. This study involved an analysis of selected mass disasters. From this an estimate was made from a verified casualty profile of the necessary minimum stock of human allogeneic skin graft materials. An insufficient amount of skin results from an inadequate number of skin donors, which in turn results from the current tissue donation system. Therefore, a proposal has been made for the organizational, legal and systemic changes required to improve the situation in Polish transplantology, with particular emphasis on skin donation. In order to achieve a strategic stock of human skin grafts, a tissue collecting transplantation team should be organized. The rights and obligations of the non-physician transplant team member should be extended. Proposals have been made for awareness campaigns (adverts, posters etc.) and educational schemes (educational video, lectures during transplant coordinator training, etc.). Finally, a proposal has been made for possible methods to deal with the logistic management of the allogeneic skin stock. The required, essential stock of human allogeneic skin in the event of a mass disaster has been estimated at 600,000 cm2.

A Survey of 1000 Respondents on the Polish Population's Knowledge and Attitudes about Tissue/Organ Donation and Transplantation in Times of Allogeneic Tissue Shortage

Tissue-engineered human allogeneic skin grafts retrieved from a deceased donor play an important role in the therapy of extensive and deeply burned patients. However, there is a vital deficit of allogeneic skin donors, and the reserves of human allogeneic skin grafts are not sufficient. The goal of this work was to analyze the level of knowledge and attitudes of Polish society in the field of transplantation, with particular emphasis on allogeneic skin transplantation. The study used a self-made questionnaire comprised of 23 questions. 1000 respondents took part in this research. The respondents were a diverse group in terms of age, sex, education, and place of residence. The obtained results show a general positive attitude of the respondents towards the idea of transplantology. However, people with lower education presented a more negative attitude towards the donation of tissues and organs. Additionally younger people were not able to clearly declare readiness for organ procurement. What is more data analysis revealed certain gaps in more detailed knowledge and surprising attitudes. In that respect, the lack of awareness about the criteria for determining brain death could be mentioned. There was also a lack of acceptance for skin procurement in specific population groups. It can therefore be concluded that a key role in the success of the idea of transplantation in Poland is the broad and systematic education of the society.

Influence of electron beam irradiation on extracellular matrix of the human allogeneic skin grafts

The nonviable allogeneic human skin grafts might be considered as the most suitable skin substitutes in the treatment of extensive and deep burns. However, in accordance to biological security such grafts require the final sterilization prior to clinical application. The aim of the study was to verify the influence of electron beam irradiation of three selected doses: 18, 25, and 35 kGy on the extracellular matrix of human skin. Prior to sterilization, the microbiological tests were conducted and revealed contamination in all examined cases. Individual groups were subjected to single electron beam radiation sterilization at proposed doses and then subjected to microbiological tests again. The results of microbiological testing performed for all irradiation doses used were negative. Only in the control group was a growth of microorganisms observed. The FTIR spectrometry tests were conducted followed by the histological evaluation and mechanical tests. In addition, cost analysis of radiation sterilization of individual doses was performed. The results of spectroscopic analysis, mechanical tests, and histological staining showed no significant changes in composition and characteristics of tested tissues after their irradiation, in comparison to control samples. The cost analysis has shown that irradiation with 18 kGy is the most cost-effective and 35 kGy is the least favorable. However, according to biological risk reduction, the recommended sterilization dose is 35 kGy, despite the higher price compared to the other doses tested.