In Vitro Cytocompatibility Analysis and Comparison of Different Hyaluronic Acid Fillers for Minimally Invasive Esthetics.

BACKGROUND/AIM: To overcome the natural visual consequences of the physiological aging process, the use of biodegradable fillers made of hyaluronic acid or sodium carboxymethyl cellulose is increasingly popular in modern esthetic medicine. Clinicians can choose from a wide range of fillers with variable compositions and rheological properties, and therefore with different application areas and injection depths. The aim of this study was to analyze and compare the most commonly used fillers for facial augmentation regarding their in vitro biocompatibility and to find potential correlations to their rheological properties. MATERIALS AND METHODS: In the present study, direct and indirect in vitro cytotoxicity analysis according to DIN EN ISO 10993-5 were performed on 39 different filler materials for facial augmentation. RESULTS: All fillers analyzed in this study overall showed satisfactory results in the direct and indirect cytocompatibility tests. While no material was outside the threshold values in the 2,3-bis-(2-methoxy-4-nitro-5-sulphenyl)-(2H)-tetrazolium-5-carboxanilide (XTT) cell viability and bromodeoxyuridine (BrdU) cell proliferation assays or in the live-dead staining, only 7 out of the 39 fillers reached the required values in the lactate dehydrogenase assay. CONCLUSION: All biodegradable fillers examined in this study were found to be sufficiently cytocompatible. Although the qualitative analysis of the test results showed differences between the fillers, no concrete correlation between test performance and composition or manufacturer of the fillers was found. Future efforts are required to provide clinicians with even better support in choosing the right filler for optimal outcome and patient satisfaction.

Republication: In Vitro and Ex Vivo Analysis of Collagen Foams for Soft and Hard Tissue Regeneration.

BACKGROUND/AIM: The aim of this study was the conception, production, material analysis and cytocompatibility analysis of a new collagen foam for medical applications. MATERIALS AND METHODS: After the innovative production of various collagen sponges from bovine sources, the foams were analyzed ex vivo in terms of their structure (including pore size) and in vitro in terms of cytocompatibility according to EN ISO 10993-5/-12. In vitro, the collagen foams were compared with the established biomaterials cerabone and Jason membrane. Materials cerabone and Jason membrane. RESULTS: Collagen foams with different compositions were successfully produced from bovine sources. Ex vivo, the foams showed a stable and long-lasting primary structure quality with a bubble area of 1,000 to 2,000 µm2 In vitro, all foams showed sufficient cytocompatibility. CONCLUSION: Collagen sponges represent a promising material for hard and soft tissue regeneration. Future studies could focus on integrating and investigating different additives in the foams.

In Vitro Analysis of the Cytocompatibility of a Novel Porcine Aortic Patch for Vascular Reconstruction.

BACKGROUND/AIM: Cardiovascular diseases are one of the most common causes of morbidity and mortality in the world. In the case of severe arteriosclerotic damage, surgical treatment is necessary. Although the use of autologous vessels is still considered to be the gold standard, sufficient autologous vessels for transplantation are lacking. MATERIALS AND METHODS: In the present study, histological examination and in vitro cytotoxicity analysis according to DIN EN ISO 10993-5 were performed on a newly developed porcine vascular graft from a decellularized aorta. A conventional bovine graft was used as control. RESULTS: The ex vivo-histological analysis revealed the effectiveness of a new purification process on the microstructure and the removal of xenogeneic antigen-bearing structures in the new vessels. Furthermore, cell viability and cytotoxicity assays revealed full cytocompatibility. CONCLUSION: The novel graft shows no structural damage and gets completely decellularized by the purification process. Superior cytocompatibility, compared with the bovine-derived vascular graft, was demonstrated.

Heat Development During Medical Drilling: Influencing Factors and Examination Methods - Overview and First Results.

In many medical disciplines, the process of drilling into the bone plays a crucial role for the implantation or fixation of implants or reconstruction plates. During the bone drilling process, heat is generated on the drill head and within the surrounding tissue. As a result, the increased temperature can lead to thermal damage and related necrosis of the (bone) tissue. This tissue damage is dependent on different drilling parameters and can have important influence on the following tissue healing cascade and finally on implant surveillance. In this context, the present short review elucidates the current state of scientific knowledge with regard to the heat-triggering factors during the bony drilling process and how these factors can be better understood and prevented, now and in the future, through new research approaches. External and internal influencing factors during the drilling process are distinguished and methods to examine the temperature changes are compared. This mini-review further demonstrates first preliminary results of the inflammatory tissue reactions to inadequate drilling processes. Furthermore, possible solutions of new standardized ex vivo-measurement methods to better understand the factors influencing the development of heat and to reduce animal experiments are herein discussed.

Combining Biocompatible and Biodegradable Scaffolds and Cold Atmospheric Plasma for Chronic Wound Regeneration.

Skin regeneration is a quite complex process. Epidermal differentiation alone takes about 30 days and is highly regulated. Wounds, especially chronic wounds, affect 2% to 3% of the elderly population and comprise a heterogeneous group of diseases. The prevailing reasons to develop skin wounds include venous and/or arterial circulatory disorders, diabetes, or constant pressure to the skin (decubitus). The hallmarks of modern wound treatment include debridement of dead tissue, disinfection, wound dressings that keep the wound moist but still allow air exchange, and compression bandages. Despite all these efforts there is still a huge treatment resistance and wounds will not heal. This calls for new and more efficient treatment options in combination with novel biocompatible skin scaffolds. Cold atmospheric pressure plasma (CAP) is such an innovative addition to the treatment armamentarium. In one CAP application, antimicrobial effects, wound acidification, enhanced microcirculations and cell stimulation can be achieved. It is evident that CAP treatment, in combination with novel bioengineered, biocompatible and biodegradable electrospun scaffolds, has the potential of fostering wound healing by promoting remodeling and epithelialization along such temporarily applied skin replacement scaffolds.

In Vitro and Ex Vivo Analysis of Collagen Foams for Soft and Hard Tissue Regeneration.

BACKGROUND/AIM: The aim of this study was the conception, production, material analysis and cytocompatibility analysis of a new collagen foam for medical applications. MATERIALS AND METHODS: After the innovative production of various collagen sponges from bovine sources, the foams were analyzed ex vivo in terms of their structure (including pore size) and in vitro in terms of cytocompatibility according to EN ISO 10993-5/-12. In vitro, the collagen foams were compared with the established soft and hard tissue materials cerabone and Jason membrane (both botiss biomaterials GmbH, Zossen, Germany). RESULTS: Collagen foams with different compositions were successfully produced from bovine sources. Ex vivo, the foams showed a stable and long-lasting primary structure quality with a bubble area of 1,000 to 2,000 µm2 In vitro, all foams showed sufficient cytocompatibility. CONCLUSION: Collagen sponges represent a promising material for hard and soft tissue regeneration. Future studies could focus on integrating and investigating different additives in the foams.

Ex Vivo and In Vivo Analysis of a Novel Porcine Aortic Patch for Vascular Reconstruction.

(1) Background: The aim of the present study was the biocompatibility analysis of a novel xenogeneic vascular graft material (PAP) based on native collagen won from porcine aorta using the subcutaneous implantation model up to 120 days post implantationem. As a control, an already commercially available collagen-based vessel graft (XenoSure®) based on bovine pericardium was used. Another focus was to analyze the (ultra-) structure and the purification effort. (2) Methods: Established methodologies such as the histological material analysis and the conduct of the subcutaneous implantation model in Wistar rats were applied. Moreover, established methods combining histological, immunohistochemical, and histomorphometrical procedures were applied to analyze the tissue reactions to the vessel graft materials, including the induction of pro- and anti-inflammatory macrophages to test the immune response. (3) Results: The results showed that the PAP implants induced a special cellular infiltration and host tissue integration based on its three different parts based on the different layers of the donor tissue. Thereby, these material parts induced a vascularization pattern that branches to all parts of the graft and altogether a balanced immune tissue reaction in contrast to the control material. (4) Conclusions: PAP implants seemed to be advantageous in many aspects: (i) cellular infiltration and host tissue integration, (ii) vascularization pattern that branches to all parts of the graft, and (iii) balanced immune tissue reaction that can result in less scar tissue and enhanced integrative healing patterns. Moreover, the unique trans-implant vascularization can provide unprecedented anti-infection properties that can avoid material-related bacterial infections.

3D Printing for Soft Tissue Regeneration and Applications in Medicine.

The use of additive manufacturing (AM) technologies is a relatively young research area in modern medicine. This technology offers a fast and effective way of producing implants, tissues, or entire organs individually adapted to the needs of a patient. Today, a large number of different 3D printing technologies with individual application areas are available. This review is intended to provide a general overview of these various printing technologies and their function for medical use. For this purpose, the design and functionality of the different applications are presented and their individual strengths and weaknesses are explained. Where possible, previous studies using the respective technologies in the field of tissue engineering are briefly summarized.