Effect of Inflammatory Microenvironment on the Regenerative Capacity of Adipose-Derived Mesenchymal Stem Cells.

Adipose-derived mesenchymal stem cells are increasingly being used in regenerative medicine as cell therapy targets, including in the treatment of burns and ulcers. The regenerative potential of AD-MSCs and some of their immunological properties are known from in vitro studies; however, in clinical applications, cells are used in non-ideal conditions and can behave differently in inflammatory environments, affecting the efficacy and outcome of therapy. Our aim was to investigate and map the pathways that the inflammatory microenvironment can induce in these cells. High-throughput gene expression assays were performed on AD-MSCs activated with LPS and TNFα. Analysis of RNA-Seq data showed that control, LPS-treated and TNFα-treated samples exhibited distinct gene expression patterns. LPS treatment increased the expression of 926 genes and decreased the expression of 770 genes involved in cell division, DNA repair, the cell cycle, and several metabolic processes. TNFα treatment increased the expression of 174 genes and decreased the expression of 383 genes, which are related to cell division, the immune response, cell proliferation, and differentiation. We also map the biological pathways by further investigating the most altered genes using the Gene Ontology and KEGG databases. Secreted cytokines, which are important in the immunological response, were also examined at the protein level, and a functional assay was performed to assess wound healing. Activated AD-MSC increased the secretion of IL-6, IL-8 and CXCL-10, and also the closure of wounds. AD-MSCs presented accelerated wound healing under inflammation conditions, suggesting that we could use this cell in clinical application.

Herpes Simplex Virus Infection Alters the Immunological Properties of Adipose-Tissue-Derived Mesenchymal-Stem Cells.

The proper functioning of mesenchymal stem cells (MSCs) is of paramount importance for the homeostasis of the body. Inflammation and infection can alter the function of MSCs, which can also affect the regenerative potential and immunological status of tissues. It is not known whether human herpes simplex viruses 1 and 2 (HSV1 and HSV2), well-known human pathogens that can cause lifelong infections, can induce changes in MSCs. In non-healing ulcers, HSV infection is known to affect deeper tissue layers. In addition, HSV infection can recur after initially successful cell therapies. Our aim was to study the response of adipose-derived MSCs (ADMSCs) to HSV infection in vitro. After confirming the phenotype and differentiation capacity of the isolated cells, we infected the cells in vitro with HSV1-KOS, HSV1-532 and HSV2 virus strains. Twenty-four hours after infection, we examined the gene expression of the cells via RNA-seq and RT-PCR; detected secreted cytokines via protein array; and determined autophagy via Western blot, transmission electron microscopy (TEM) and fluorescence microscopy. Infection with different HSV strains resulted in different gene-expression patterns. In addition to the activation of pathways characteristic of viral infections, distinct non-immunological pathways (autophagy, tissue regeneration and differentiation) were also activated according to analyses with QIAGEN Ingenuity Pathway Analysis, Kyoto Encyclopedia of Genes and Genome and Genome Ontology Enrichment. Viral infections increased autophagy, as confirmed via TEM image analysis, and also increased levels of the microtubule-associated protein light chain 3 (LC3B) II protein. We identified significantly altered accumulation for 16 cytokines involved in tissue regeneration and inflammation. Our studies demonstrated that HSV infection can alter the viability and immunological status of ADMSCs, which may have implications for ADMSC-based cell therapies. Alterations in autophagy can affect numerous processes in MSCs, including the inhibition of tissue regeneration as well as pathological differentiation.

Toward better drug development: Three-dimensional bioprinting in toxicological research.

The importance of three-dimensional (3D) models in pharmacological tests and personalized therapies is significant. These models allow us to gain insight into the cell response during drug absorption, distribution, metabolism, and elimination in an organ-like system and are suitable for toxicological testing. In personalized and regenerative medicine, the precise characterization of artificial tissues or drug metabolism processes is more than crucial to gain the safest and the most effective treatment for the patients. Using these 3D cell cultures derived directly from patient, such as spheroids, organoids, and bioprinted structures, allows for testing drugs before administration to the patient. These methods allow us to select the most appropriate drug for the patient. Moreover, they provide chance for better recovery of patients, since time is not wasted during therapy switching. These models could be used in applied and basic research as well, because their response to treatments is quite similar to that of the native tissue. Furthermore, they may replace animal models in the future because these methods are cheaper and can avoid interspecies differences. This review puts a spotlight on this dynamically evolving area and its application in toxicological testing.

Tissue engineered skin products in research and therapeutic applications. / Mesterséges borszövetek a kutatásban és a gyógyításban.

Összefoglaló. A borpótlóknak mind a klinikumban, mind a gyógyszerkutatásokban kiemelt szerepük van. Ezek a kezdetleges mesterséges borszövetek segíthetik a bor regenerálódását, modellezhetik a fobb funkciókat, de megvannak a korlátaik is, mechanikailag sérülékenyek, és nem tartósak. A legtöbb borpótló vagy acelluláris, vagy csak egy-két sejttípust tartalmaz. Az eredeti borrel megegyezo szerkezetu, teljesen funkcionális mesterséges borszövet a mai napig nem létezik. A háromdimenziós szövetnyomtatás megoldást kínálhat erre a problémára is, hiszen a borszövet minden sejtes eleme felhasználható, megfelelo hidrogélek és biotinták segítségével pedig olyan komplex struktúrák hozhatók létre, amelyek képesek a bor teljes funkcionális repertoárját biztosítani. Ez nemcsak klinikai szempontból kiemelt jelentoségu, hanem a preklinikai kísérletek esetében kiválthatja az állatmodelleket és számos toxikológiai vizsgálatot is. Orv Hetil. 2022; 163(10): 375-385. Summary. Skin substitutes have a prominent role in therapeutic applications and drug research. These simple artificial skin tissues can support skin regeneration, in vitro they can model the main functions of the skin but they also have limitations such as being mechanically vulnerable and not durable enough. Most skin substitutes are either acellular or contain only one or two cell types. Fully functional artificial skin substitute with the same structure as the original skin has not been produced to this day. Three-dimensional tissue bioprinting can also offer a solution to this problem, as all cellular elements of skin tissue can be used, and with the help of appropriate hydrogels and bioinks, complex structures can be created that can provide a complete functional repertoire of the skin. It is important not just in the clinical therapeutic use, but it can also trigger the replacement of animal models and a number of toxicological studies in preclinical trials. Orv Hetil. 2022; 163(10): 375-385.