This article discusses parameters relevant for successful translation of research on different cell sources into clinically applicable cell therapies: the influence of the intervertebral disc microenvironment on the cell phenotype, issues associated with cell culture and technical preparation of cell products, as well as discussing current regulatory requirements. There are advantages and disadvantages of each proposed cell type, but no strong evidence to favour any one particular cell source at the moment.

Several preventive measures have been applied to limit the COVID-19 pandemic, including successful the development and introduction of vaccines. The aim of this study was to investigate adherence to preventive measures and vaccination intentions among nursing students in three European countries and the factors associated with vaccination intention and advising vaccination. A cross-sectional study using convenience/snow-ball sampling strategy was performed in Slovenia, Poland, and Serbia between 12 February and 5 March 2021. Data from 872 eligible respondents were analyzed (mean age 23.5 ± 6.5 years, 89% female). Higher adherence to preventive behavior was declared by those working in healthcare (p < 0.001), engaged in COVID-19 departments (p < 0.001), had not had the disease yet (p < 0.001), and had children (p = 0.01). Those groups also expressed higher vaccination intention and advised vaccination to others. Higher vaccination intention and advising vaccination were mostly associated with belief in benefits of vaccine, trust in institutions, perceived effectiveness of vaccine, influence of social environment, protection of patients and perceived health care professionals’ duty. Fear of side effects and general refusal of vaccines are the main reasons for vaccination hesitancy. The results of the study indicate how higher education institutions can support the development of appropriate professional attitudes and behaviors among nursing students.

IntroductionThe first large outbreak of SARS-CoV-2 in Europe occurred in Northern Italy in February 2020. The relatively fast spread of the infection to Slovenia was expected, and preventive measures for its suppression were widely discussed.MethodsAn online questionnaire was designed to evaluate adherence to preventive measures and the extent to which the taking of preventive measures was associated with people’s anxiety level, psychological burden, their perceived vulnerability to disease, germ aversion and a number of demographic characteristics in the early stage of Covid-19 spread. The survey was active for 24 hours (13–14 March 2020). There were 12,307 responses and 7,764 questionnaires were completed in full.ResultsHigher preventive behaviour was found in individuals who experienced greater psychological distress, were more anxious, and expressed greater perceived infectability and germ aversion. Greater compliance with preventive behaviour was found among women, those sharing a household with people aged over 65, the elderly and those who knew somebody who had been infected. These groups also showed higher anxiety levels, which appeared to be significantly increased in general as a result of the specific situation. Quarantine was evaluated as the most efficient preventive measure, and was respected relatively strictly even before it became an officially announced protective measure.ConclusionThis research reveals a strong association between preventive behaviour and anxiety. Anxiety, together with social distancing, may affect physical and psychological health in the population in the long term. Other aspects of public health might therefore be influenced by the measures currently being enforced to prevent the spread of SARS-CoV-2.

Auricular cartilage is an attractive potential source of cells for many tissue engineering applications. However, there are several requirements that have to be fulfilled in order to develop a suitable tissue engineered implant. Animal experiments serve as important tools for validating novel concepts of cartilage regeneration; therefore rabbit auricular chondrocytes were studied. Various parameters including isolation procedures, passage number, rate of proliferation and gene expression profile for major extracellular matrix components were evaluated in order to assess the potential use of elastic chondrocytes for tissue engineering. Chondrocytes were isolated from rabbit ear cartilage and grown in monolayer cultures over four passages. Yields of harvested cells and proliferation were analysed from the digestion step to the fourth passage, and changes in phenotype were monitored. The proliferation capacity of cell cultures decreased during cultivation and was accompanied by enlargement of cells, this phenomenon being especially evident in the third and fourth passages. The expression of cartilage specific genes for collagen type II, aggrecan and cartilage non-specific collagen type I was determined. The mRNA levels for all three genes were obviously lower in the primo culture than immediately after isolation. During subsequent cultivation the expression of collagen type II decreased further, while there were only slight changes in expression of aggrecan and collagen type I. This study provides a valuable basis for testing of different tissue engineering applications in rabbit model, where auricular chondrocytes are considered as cell source.

A scaffold made of equine collagen type I based material has been assessed for its use in the preparation of tissue-engineered cartilage implants with human articular chondrocytes. Improvements of cell-seeding efficiency and specific gene expression were studied by combining solid scaffold with fibrin glue or human blood plasma. Following 3 weeks of static culture, mRNA expression levels of collagen type I, collagen type II, aggrecan and versican were analyzed by real-time quantitative PCR and compared to those in native cartilage and monolayer cell cultures. Constructs prepared with fibrin glue or plasma showed higher cell seeding efficiencies than those prepared without gel. Chondrocytes seeded directly onto a collagen scaffold appeared fibroblastic in shape while those encapsulated in fibrin gel were spherical. The presence of fibrin glue positively influences on mRNA levels of collagen type II and aggrecan, while blood plasma enhanced only the level of collagen type II expression. Levels of collagen type I and versican decreased in presence of fibrin glue. In orthopaedics, the combination of solid collagen fleece with fibrin gel for implant preparation is seen to be preferred over solid material or even cells in a suspension, since fibrin gel improves seeding capacity of the scaffold, supports equal distribution of cells and stimulates higher chondrogenic phenotype expression.

The ability to enhance bone regeneration by implanting autologous osteoblasts in combination with an appropriate scaffold would be of great clinical interest. The aim of our study was to compare the growth and differentiation of alveolar bone cells in tissue-engineered constructs and in monolayer cultures, as the basis for developing procedures for routine preparation of bone-like tissue constructs. Alveolar bone tissue was obtained from four human donors and explant cultures of the cells were established. Expanded cells were seeded on macroporous hydroxyapatite granules, and cultured in medium supplemented with osteogenic differentiation factors for up to 3 weeks. Control monolayer cultures were established in parallel, and cultured in media with or without osteogenic supplements. Cell proliferation, alkaline phosphatase (AP) activity and gene expression of AP, osteopontin and osteocalcin were determined under different culture conditions at weekly intervals. Cells in tissue constructs exhibited growth patterns similar to those in control monolayer cultures: enhanced proliferation was noted during the first 2 weeks of cultivation, followed by a decrease in cell numbers. AP activity at 3 weeks was higher in all cultures in osteogenic medium than in control medium. Gene expression levels were stable in monolayer cultures in both types of media whereas, in tissue constructs, they exhibited patterns of osteogenic differentiation. Light and scanning electron microscopy examination of the cell-seeded constructs showed uniform cell distribution, as well as cell attachment and growth into the interior region of the hydroxyapatite granules. Our results show that bone-like constructs with viable cells exhibiting differentiated phenotype can be prepared by cultivation of alveolar-bone cells on the tested hydroxyapatite granules.

Most studies of long-term chondrocytes survival were for tissue banks. They showed a gradual reduction in the viable chondrocytes percentage as a function of time and ambient temperature, but the samples were harvested under optimal conditions. The aim of our study was to determine the most reliable combination of cartilage source and assay for the in vitro postmortem chondrocyte viability analysis in the conditions that imitate a dead body. Osteochondral cylinders were procured from femoral condyles and talar trochleas of three male donors and stored in the cell culture media at 4 ± 2°C and 23 ± 2°C. The samples were analyzed by a cell viability analyzer and a confocal laser scanning microscope (CLSM) initially 24-36 h after death and then in 4-week intervals. The results reconfirmed the significant influence of time (p = 0.0002), but not of the temperature (p = 0.237). The largest reproducibility was presented for the knee joint and the CLSM.

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