Evaluation of Human Skin-Derived Stem Cell Characteristics After Non-Invasive Quantum Dot Labeling.

BACKGROUND/AIMS: The use of skin-derived stem cells and stem cells of other origins in regenerative medicine requires knowledge of stem cell fate after transplantation. In order to achieve non-invasive long-term imaging and tracking of transplanted stem cells in preclinical studies, a non-toxic, efficient labeling technique that does not alter stem cell characteristics must be used. Our aim was to investigate a method for such a long-term cell-compatible cell tracer using nanoparticles. METHODS: Nanotechnology, in particular the use of quantum dots (QDs), offers great advantages for this crucial requirement. In this study, we used nanocrystals coated with a specific target peptide that enables delivery into the cytoplasm of cells, resulting in an intense and stable fluorescent labeling. We analyzed the influence of biocompatible CdSe/ZnS-QDs on epidermal stem cells (EpiSCs) isolated from adult human skin. Thereby we analyzed on QD loading, cell proliferation including QD transfer to descendent daughter cells as well as the influence on the differentiation potential of stem cells after QD labeling. RESULTS: FACS analysis revealed a dose-dependent QD incorporation into the cells. Thereby, a high initial concentration of nanocrystals resulted in a more stable long-term labeling. QD labeled cells showed normal viability and unchanged ability to proliferate. The spread of QDs during cell division was monitored by time lapse microscopy and two modes of QD distribution could be observed. Daughter cells either received an equal amount of QDs after cell division, which led to a homogenously faded fluorescence signal, or there was an uneven transmission of QDs, which led to unchanged labeling of one cell and a complete loss of the fluorescence signal of the other cell. The spontaneous differentiation potential remained unaffected after QD exposure, since skin-derived EpiSCs showed an unchanged protein and gene expression profile. CONCLUSION: In summary, we can conclude that QDs offer a successful, non-invasive and efficient labeling technique for EpiSCs, which makes their in vitro and in vivo use in skin regeneration and wound healing models traceable. Nevertheless, the uneven transmission of QDs should not be disregarded and the extent and frequency should be investigated in further studies.

ROBOTONT - Open-source and ROS-supported omnidirectional mobile robot for education and research.

In order to achieve visionary concepts such as Society 5.0 and Industry 5.0, there is a growing need for people who are able to create innovative robotic technologies. Training students to become such skilled professionals requires transitioning from often toy-like educational platforms with significant hardware limitations to costly research robots with full ROS (Robot Operating System) support. To aid in this transition, we propose Robotont - an open-source omnidirectional mobile robot platform with both physical hardware and a digital twin. Robotont enables robotics education with professional tools as well as provides researchers with a capable mobility platform for validating and demonstrating scientific results. Robotont has successfully been used for university teaching, professional education, and online courses about ROS and robotics.

Establishment of a Robust and Simple Corneal Organ Culture Model to Monitor Wound Healing.

The use of in vitro systems to investigate the process of corneal wound healing offers the opportunity to reduce animal pain inflicted during in vivo experimentation. This study aimed to establish an easy-to-handle ex vivo organ culture model with porcine corneas for the evaluation and modulation of epithelial wound healing. Cultured free-floating cornea disks with a punch defect were observed by stereomicroscopic photo documentation. We analysed the effects of different cell culture media and investigated the impact of different wound sizes as well as the role of the limbus. Modulation of the wound healing process was carried out with the cytostatic agent Mitomycin C. The wound area calculation revealed that after three days over 90% of the lesion was healed. As analysed with TUNEL and lactate dehydrogenase assay, the culture conditions were cell protecting and preserved the viability of the corneal tissue. Wound healing rates differ dependent on the culture medium used. Mitomycin C hampered wound healing in a concentration-dependent manner. The porcine cornea ex vivo culture ideally mimics the in vivo situation and allows investigations of cellular behaviour in the course of wound healing. The effect of substances can be studied, as we have documented for a mitosis inhibitor. This model might aid in toxicological studies as well as in the evaluation of drug efficacy and could offer a platform for therapeutic approaches based on regenerative medicine.

Nestin+ progenitor cells isolated from adult human sweat gland stroma promote reepithelialisation and may stimulate angiogenesis in wounded human skin ex vivo.

The combination of an aging population and an increasing prevalence of diseases associated with impaired-wound healing, including obesity, peripheral vascular disease and diabetes, is likely to result in a dramatic increase in the incidence and prevalence of chronic skin wounds. Indeed, systemic reviews are now not only trying to establish both the prevalence and the often under-estimated socio-economic costs of chronic skin wounds, but most importantly are addressing the impact that chronic wounds have on quality of life. Given the clear need for novel approaches to the management of chronic skin ulceration, ideally developed and tested in the human system in a manner that can be rapidly translated into clinical practice, we examined the effects of multipotent primary human nestin+ progenitor cells on human wound healing in an ex vivo model. Human sweat gland-derived nestin+ cells demonstrated the capacity to significantly promote two key wound healing parameters, i.e., both reepithelialisation and angiogenesis in experimentally wounded, organ-cultured human skin. The current data further support the use of full-thickness human skin wound-healing models ex vivo to pre-clinically test wound healing-promoting candidate agents. Whilst larger studies are required to substantiate a firm "proof-of-concept," our preliminary studies encourage further efforts to systemically determine the potential of cell-based regenerative medicine strategies in general, and the use of skin appendage-associated human nestin+ cells in particular, as novel treatment strategies for chronic skin ulceration.

Neuronal Differentiation Capability of Nasal Polyps of Chronic Rhinosinusitis.

Chronic rhinosinusitis with nasal polyps is considered a subgroup of chronic rhinosinusitis and a significant health problem, but the pathogenesis remains unclear to date. Therefore, we investigated the stemness to determine the role of stem cells in nasal polyps, with additional analysis of the neuronal differentiation potential of nasal polyp cells. We determined gene and protein expression profiles of stem cells in nasal polyp tissues, using whole genome microarray, quantitative real-time PCR (qPCR), immunohistochemistry, and flow cytometry. To evaluate the neuronal differentiation potential of nasal polyp cells, we used an efficient xenogeneic co-culture model with unsliced adult rat brain biopsies, followed by qPCR, immunohistochemistry, and growth factor antibody arrays. During gene expression analysis and immunohistochemistry, we were able to detect different stem cell markers, like Oct-4, Sox2, Klf4, c-Myc, ABCG2, Nanog, CD133, and Nestin, which confirmed the existence of stem cell like cells within nasal polyps. In addition, co-culture experiments give evidence for a guided differentiation into the neuronal lineage by overexpression of Nestin, Neurofilament, and GM-CSF. Our study demonstrated the expression of stem cell-related markers in nasal polyps. Furthermore, we characterized, for the first time, the stemness and neuronal differentiation potential of nasal polyp cells. These results gave new insights into the pathogenesis of nasal polyps and its therapeutic effectiveness could represent a promising strategy in the future.

Outcome quality assessment by surgical process compliance measures in laparoscopic surgery.

OBJECTIVE: The effective and efficient assessment, management, and evolution of surgical processes are intrinsic to excellent patient care. Hence, in addition to economic interests, the quality of the outcome is of great importance. Process benchmarking examines the compliance of an intraoperative surgical process to another process that is considered as best practice. The objective of this work is to assess the relationship between the course and the outcome of surgical processes of the study. MATERIALS AND METHODS: By assessing 450 skill practices on rapid prototyping models in minimally invasive surgery training, we extracted descriptions of surgical processes and examined the hypothesis that a significant relationship exists between the course of a surgical process and the quality of its outcome. RESULTS: The results showed a significant correlation with Person correlation coefficients >0.05 between the quality of process outcome and process compliance for simple and complex suturing tasks in the study. CONCLUSIONS: We conclude that high process compliance supports good quality outcomes and, therefore, excellent patient care. We also showed that a deviation from best training processes led to a decreased outcome quality. This is relevant for identifying requirements for surgical processes, for generating feedback for the surgeon with regard to human factors and for inducing changes in the workflow in order to improve the outcome quality.

LPS-Stimulated Human Skin-Derived Stem Cells Enhance Neo-Vascularization during Dermal Regeneration.

High numbers of adult stem cells are still required to improve the formation of new vessels in scaffolds to accelerate dermal regeneration. Recent data indicate a benefit for vascularization capacity by stimulating stem cells with lipopolysaccharide (LPS). In this study, stem cells derived from human skin (SDSC) were activated with LPS and seeded in a commercially available dermal substitute to examine vascularization in vivo. Besides, in vitro assays were performed to evaluate angiogenic factor release and tube formation ability. Results showed that LPS-activated SDSC significantly enhanced vascularization of the scaffolds, compared to unstimulated stem cells in vivo. Further, in vitro assays confirmed higher secretion rates of proangiogenic as well as proinflammatoric factors in the presence of LPS-activated SDSC. Our results suggest that combining activated stem cells and a dermal substitute is a promising option to enhance vascularization in scaffold-mediated dermal regeneration.