The recent pandemic situation transpired due to coronavirus novel strain SARS-CoV-2 has become a global concern. This human coronavirus (HCov-19) has put the world on high alert as the numbers of confirmed cases are continuously increasing. The world is now fighting against this deadly virus and is leaving no stone unturned to find effective treatments through testing of various available drugs, including those effective against flu, malaria, etc. With an urgent need for the development of potential strategies, two recent studies from China using Mesenchymal Stem Cells (MSCs) to treat COVID-19 pneumonia have shed some light on a potential cure for the COVID-19 infected patients. However, MSCs, despite being used in various other clinical trials have always been questioned for their tendency to aggregate or form clumps in the injured or disease microenvironment. It has also been reported in various studies that exosomes secreted by these MSCs, contribute towards the cell's biological and therapeutic efficacy. There have been reports evaluating the safety and feasibility of these exosomes in various lung diseases, thereby proposing them as a cell-free therapeutic agent. Also, attractive features like cell targeting, low-immunogenicity, safety, and high biocompatibility distinguish these exosomes from other synthetic nano-vesicles and thus potentiate their role as a drug delivery nano-platform. Building upon these observations, herein, efforts are made to give an overview of stem cell-derived exosomes as an appealing therapeutic agent and drug delivery nano-carrier. In this review, we briefly recapitulate the recent evidence and developments in understanding exosomes as a promising candidate for novel nano-intervention in the current pandemic scenario. Furthermore, this review will highlight and discuss mechanistic role of exosomes to combat severe lung pathological conditions. We have also attempted to dwell into the nano-formulation of exosomes for its better applicability, storage, and stability thereby conferring them as off the shelf therapeutic.
Mesenchymal Stem Cells (MSCs) derived Extracellular Vesicles (EVs) have emerged as an effective candidate for amelioration of liver fibrosis. However, the effect and the mechanisms of MSC-EVs in liver repair remains elusive. In this study, we have evaluated the differential regenerative efficacy of EVs derived from two different human tissue-specific MSCs (Adipose tissue; AD-MSC and Wharton's Jelly; WJ-MSC), in a murine model of chronic liver fibrosis. Mouse model of chronic liver injury was induced by carbon tetrachloride (CCl 4 ) injection, followed by administration of EVs via the tail vein. Both quantitative and qualitative assessment was done to evaluate the hepatic regenerative potential of tissue specific MSC-extracellular vesicles. EVs, regardless of their MSC source, were found to be effective in alleviating chronic liver fibrosis, as demonstrated by macroscopic alterations in the liver. According to the findings of the comprehensive study, there were subtle variations in the tissue specific MSCs-EVs mediated approaches. A greater anti-fibrotic impact was demonstrated by AD-MSC derived EVs through extracellular matrix alteration and hepatocyte proliferation. WJ-MSC EVs, on the other hand, have an anti-inflammatory effect, as evidenced by alterations in the expression of pro-and anti-inflammatory cytokines. Furthermore, cargo profiling of these EVs revealed differences in the miRNA and protein expression, as well as the pathways that they were associated.
Keratinized regions were found to occur in the rostral cap, adhesive pad and horny jaw sheaths associated with the lips of Garra lamta, which inhabits fast flowing turbulent hill streams. In these structures, the surface epithelial cells were modified into characteristic keratinized spine-like or columnar tooth-like unculi, which would provide firm anchorage for the fish on the substratum and assist the fish in browsing or scraping food materials from it. # 2004 The Fisheries Society of the British Isles
The surface architecture of the structures associated with the lips of a hill stream fish Garra lamta was examined by scanning electron microscopy. In this teleost, the lips are inconspicuous and associated with prominent horny jaw sheaths. Furthermore, the upper and lower lips are associated with a greatly enlarged rostral cap and an adhesive pad, respectively. The rostral cap has a proximal mucogenic region and a distal keratinized region. The adhesive pad is differentiated into central mucogenic and peripheral keratinized regions. At the mucogenic regions of the rostral cap and the adhesive pad, the surface of the epithelial cells is characterised by well developed microridges, which reflect their high secretory activity. The mucus may lubricate the surface and protect the epithelia from abrasions at these regions, which are likely to be subjected to wear and tear during frequent friction and adhesion of the fish to the substrate. Taste buds may help the fish to locate food and trigger a 'pick-up' reflex. The epithelial cells at the surface of the keratinized regions of the rostral cap and the adhesive pad are modified as clusters of spine like unculi, which may assist the fish in its firm anchorage to the substrate. The epithelial cells at the surface of the horny jaw sheaths are modified as polygonal unculi, each appears much like a tooth that has a characteristic sharp edge at the margin. These may be regarded as an adaptation to browsing or scraping food materials from the substrate.
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