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Pulmonary fibrosis, a debilitating lung disorder characterised by excessive fibrous tissue accumulation in lung parenchyma, compromises respiratory function leading to a life‐threatening respiratory failure. While its origins are multifaceted and poorly understood, the urokinase system, including urokinase‐type plasminogen activator (uPA) and its receptor (uPAR), plays a significant role in regulating fibrotic response, extracellular matrix remodelling, and tissue repair. Mesenchymal stem/stromal cells (MSCs) hold promise in regenerative medicine for treating pulmonary fibrosis. Our study aimed to investigate the potential of MSCs to inhibit pulmonary fibrosis as well as the contribution of uPAR expression to this effect. We found that intravenous MSC administration significantly reduced lung fibrosis in the bleomycin‐induced pulmonary fibrosis model in mice as revealed by MRI and histological evaluations. Notably, administering the MSCs isolated from adipose tissue of uPAR knockout mice (Plaur‐/‐ MSCs) attenuated lung fibrosis to a lesser extent as compared to WT MSCs. Collagen deposition, a hallmark of fibrosis, was markedly reduced in lungs treated with WT MSCs versus Plaur‐/‐ MSCs. Along with that, endogenous uPA levels were affected differently; after Plaur‐/‐ MSCs were administered, the uPA content was specifically decreased within the blood vessels. Our findings support the potential of MSC treatment in attenuating pulmonary fibrosis. We provide evidence that the observed anti‐fibrotic effect depends on uPAR expression in MSCs, suggesting that uPAR might counteract the uPA accumulation in lungs. [ABSTRACT FROM AUTHOR]

The influence of a disperse medium (paraffin oil) on the pore size distribution in Ca3(PO4)2-based ceramic materials designed for bioresorbable implants is studied. The pore size is found to affect the mechanical properties of such materials. The use of photocurable emulsions for the preparation of ceramic materials with a porosity higher than 50% is shown to be promising. The possibility of controlling the pore size distribution is demonstrated. The pore size decreases from 275 to 100 μm as the emulsifier content in the emulsion increases from 0.035 to 0.25 wt %. The uniaxial ultimate compressive strength of the ceramics with a relative density of 52% and an average pore size of 250 μm is 2.87 MPa. [ABSTRACT FROM AUTHOR]

The possibility of obtaining highly porous hydrogel composite materials for biomedical applications based on tricalcium phosphate in a polyethylene glycol diacrylate matrix, aimed at repairing bone defects, has been studied. The effect of different content of inorganic filler particles exerted on the mechanical characteristics of highly porous hydrogel composites β-Ca3(PO4)2/polyethylene glycol diacrylate has been studied. It is demonstrated that the preparation of highly porous composite materials with specified elastic properties is quite possible. The viscoelastic properties of the obtained materials are shown to depend on the preset pore size. Varying the tricalcium phosphate fraction in the highly porous hydrogel material makes it possible to control the relative stiffness of the composite. [ABSTRACT FROM AUTHOR]

The effect of the pore size of macroporous ceramic materials based on β-Ca3(PO4)2 on their biological activity was studied. The formation conditions of macroporous ceramics with a porosity of >50% and a specified pore size were determined. The effect of components of the light-curing emulsion on the pore size in the final macroporous ceramics was studied. The biocompatibility of β-Ca3(PO4)2-based macroporous ceramics was demonstrated in in vitro biomedical assays. The effect of pore size of macroporous ceramic materials on mesenchymal stromal cell proliferation and viability was established. [ABSTRACT FROM AUTHOR]

Regeneration is a fundamental process attributed to the functions of adult stem cells. In the last decades, delivery of suspended adult stem cells is widely adopted in regenerative medicine as a leading means of cell therapy. However, adult stem cells cannot complete the task of human body regeneration effectively by themselves as far as they need a receptive microenvironment (the niche) to engraft and perform properly. Understanding the mechanisms underlying mammalian regeneration leads us to an assumption that improved outcomes of cell therapy require a specific microenvironment that is generated in damaged areas prior to stem cell delivery. To a certain extent, it may be achieved by the delivery of mesenchymal stromal cells (MSCs), not in dispersed form, but rather in self-organized cell sheets (CS) – tissue-like structures comprised of viable cells and microenvironment components: extracellular matrix and soluble factors deposited in the matrix. In this review, we highlight the potential role of MSCs as regeneration organizers and speculate that this function emerges in CS. This concept shifts our understanding of the therapeutic mechanism underlying a widely known CS-based delivery method for regenerative medicine. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the representation and localization of FAP-positive activated stromal cells depending on the severity of fibrotic changes in tissues of patients with a confirmed diagnosis of COVID-19., Material and Methods: 20 autopsy observations of patients who died from COVID-19 were studied. Immunohistochemical studies were performed using antibodies to CD90, FAP and aSMA and a dual imaging system. The severity of fibrosis in lung tissue was assessed according to the R.Hubner scale (2008)., Results: FAP-positive cells are detected in the lungs, kidneys, liver and myocardium, while only in the lungs FAP expression is associated with fibrotic tissue areas. FAP expression of varying intensity was observed in capillaries, alveolar and bronchial epithelium, as well as in fibrotic nodules in the lungs, where it partially colocalizes with the key myofibroblast marker aSMA. CD90-positive stromal cells were also predominantly found in fibrotic foci., Conclusion: The results obtained allow us to clarify the localization of activated stromal precursors in human tissues during injury and suggest an important role of FAP in the formation of fibrotic foci and the progression of fibrotic changes in tissues, primarily the lungs, which makes it a promising pharmaceutical target for the treatment of diseases associated with the development of fibrosis.

The study aims to assess the role of EU biomedical research infrastructures in the fight against the COVID-19 pandemic and to analyze their response to the challenges associated with the spread of the new pathogen., Materials and Methods: We analyzed the materials of the Seventh Framework Program for Research and Technological Development (FP7, 2007-2013) of the EU and the Eighth Framework Program "Horizon 2020" (FP8, 2014-2020), official reports of the European Strategic Forum on Research Infrastructures, expert reports, as well as documents of the European Commission, the COVID-19 Data Portal, and other relevant sources of information., Results: The analysis revealed that the mechanisms created within the united European research community provided for a flexible response to the emerging threat of COVID-19 as soon as January-May 2020. In particular, information channels were established to timely analyze the research results and coordinate the efforts in the fight against COVID-19. The biomedical infrastructures created in the EU and proved successful earlier have now been mobilized to search for ways of preventing and treating COVID-19. These mechanisms facilitated communication and data exchange between various research institutions and thus laid the ground for new achievements in this area., Conclusion: The decisions taken to combat the COVID-19 pandemic have convincingly illustrated that the EU research infrastructures, integrated into a united ecosystem, are highly adaptable and flexible, which allows to realign priorities in a short time and to create instruments that enable scientists to respond to new challenges., Competing Interests: Conflict of interest. There are no conflicts of interest associated with this study.