Tissue engineering (TE) is a field of regenerative medicine that has been experiencing a special boom in recent years. Among various materials used as components of 3D scaffolds, naturally formed chitinous materials seem to be especially attractive because of their abundance, non-toxic and eco-friendly character. In this study, chitinous skeleton isolated from the marine sponge Aplysina fistularis (phylum: Porifera) was used for the first time as a support for the cultivation of murine fibroblasts (Balb/3T3), human dermal fibroblasts (NHDF), human keratinocyte (HaCaT), and human neuronal (SH-SY5Y) cells. Characterization techniques such as ATR FTIR, TGA, and μCT, clearly indicate that an interconnected macro-porous, thermostable, pure α-chitin scaffold was obtained after alkali–acid treatment of air-dried marine sponge. The biocompatibility of the naturally formed chitin scaffolds was confirmed by cell attachment and proliferation determined by various microscopic methods (e.g., SEM, TEM, digital microscopy) and specific staining. Our observations show that fibroblasts and keratinocytes form clusters on scaffolds that resemble a skin structure, including the occurrence of desmosomes in keratinocyte cells. The results obtained here suggest that the chitinous scaffold from the marine sponge A. fistularis is a promising biomaterial for future research about tissues regeneration.

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Background: Acute myocarditis often progresses to heart failure because there is no effective, etiology-targeted therapy of this disease. Simvastatin has been shown to be cardioprotective by decreasing matrix metalloproteinases’ (MMPs) activity. The study was designed to determine whether simvastatin inhibits MMPs activity, decreases the severity of inflammation and contractile dysfunction of the heart in experimental autoimmune myocarditis (EAM). Methods: Simvastatin (3 or 30 mg/kg/day) was given to experimental rats with EAM by gastric gavage for 21 days. Then transthoracic echocardiography was performed, MMPs activity and troponin I level were determined and tissue samples were assessed under a light and transmission electron microscope. Results: Hearts treated with simvastatin did not show left ventricular enlargement. As a result of EAM, there was an enhanced activation of MMP-9, which was significantly reduced in the high-dose simvastatin group compared to the low-dose group. It was accompanied by prevention of myofilaments degradation and reduction of severity of inflammation. Conclusions: The cardioprotective effects of simvastatin in the acute phase of EAM are, at least in part, due to its ability to decrease MMP-9 activity and subsequent decline in myofilaments degradation and suppression of inflammation. These effects were achieved in doses equivalent to therapeutic doses in humans.

IntroductIon Exosomes are currently considered as the new biomarkers of colorectal cancer (CRC). Tetraspanins (CD9, CD63) belong to the well -known exosome markers, but can also be found on other subtypes of extracellular vesicles (EVs).objEctIvEs The aim of this study was to estimate the expression level of exosome markers and EVs in CRC. PAtIEnts And mEthodsThe expression level of CD9 and CD63 antigens was evaluated by immunohistochemical staining in 109 patients diagnosed with CRC. Immunohistochemistry results were verified by nanoparticle tracking analysis (NTA), as well as the Western blot analysis and transmission electron microscopy. Exosomes isolation was performed on solid tissues. The immunohistochemical expression of both tetraspanins was compared with expression of cellular proliferation marker, Ki -67.rEsuLts A higher expression level of exosome markers was observed in CRC compared with the normal colonic mucosa. The NTA revealed higher concentrations of nanoparticles in CRC tissues than in controls. There was a strong positive correlation between exosome markers and the Ki -67 antigen. The expression levels of both tetraspanins were different for lymph node staging (N stage).concLusIons Exosome markers and EVs were more pronounced in the CRC samples compared with controls. Immunohistochemical evaluation of tetraspanins reflects the results obtained by the NTA. Exocytosis appears to play an important role in the pathogenesis of CRC. To the best of our knowledge, such analysis was carried out for the first time.

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