Allogenic platelet-rich plasma for treating cartilage injury: A systematic review of the evidence on the basic sciences for potential future applications.

It is apparent that whilst many reports are available regarding Platelet-Rich-Plasma (PRP), the larger majority of these have been mainly focused on autologous sources, and for good reason. Issues relating to allogenic source have been consciously avoided owing to concerns of cross infectivity and immune rejection. However, this topic today is now revisited and is of interest since progress over the year have demonstrated its safety, efficacy and its abundance of supply. The present systematic review was thus conducted to elucidate advances made in this area, with the aim to provide a wider and deeper understanding of studies relevant to the application of allogenic PRP in cartilage repair. Literature search was conducted systematically using Medline, ProQuest, Web of Science, Cochrane Central Register of Controlled Trials, and snowballing searching strategy to identify relevant studies using topic-specific keywords in various combinations including "allogenic, platelet, rich, plasma" OR "allogeneic, platelet, rich, plasma" OR "allogenic platelet-rich plasma" OR "allogeneic platelet-rich plasma" OR "allogenic platelet rich plasma" OR "allogeneic platelet rich plasma AND cartilage OR chondrocytes OR synoviocytes OR stem cells. Studies that used allogenic PRP in an attempt to facilitate cartilage repair were included. The risk of bias was assessed by the SYRCLE's checklist. Of 206 studies identified, 12 were found eligible. Only those studies that are clearly related and specific to allogenic PRP were included. Of these, nine investigated the efficacy of allogenic PRP in animal models, while three articles employed an in vitro model. Allogenic PRP promotes cell proliferation, cartilage matrix production and anti-inflammatory effects in vitro. The in vivo studies reported histological evidence of significant acceleration of cartilage repair in treated animals. Despite several conflicting findings, all studies agreed that allogenic PRP is safe and potentially efficacious for cartilage repair, with the advantages of allogenic sources apparent.

Warthin-Starry Staining for the Detection of Helicobacter pylori in Gastric Biopsies.

BACKGROUND: Warthin-Starry (WS) staining is an ancillary stain used in the detection of Helicobacter sp., spirochaete and other microorganisms in tissue sections. The present study aimed to determine the validity of WS stain in the confirmation of H. pylori diagnosis in gastric biopsies in comparison with anti-H. pylori immunohistochemistry (IHC) staining. METHODS: This study involved 104 cases of gastric biopsies that were previously subjected to WS staining. All cases involved retrieval of formalin-fixed paraffin-embedded (FFPE) gastric biopsies that were re-cut, subjected to anti-H. pylori IHC staining and reviewed blindly by a pathologist. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of WS as compared to IHC were calculated. RESULTS: In this study, WS stain was less sensitive in detecting H. pylori. The sensitivity, specificity, PPV and NPV for WS stain were 50.0%, 92.4%, 79.2% and 76.3%, respectively. CONCLUSIONS: The sensitivity of WS stain in the histopathology laboratory was lower than that described previously. Several external factors that might influence the results were identified. However, sufficient information on patients' history of treatment and medication would be required for the diagnosis or confirmation of the presence of H. pylori in gastric biopsies by WS staining.

Comparing the Therapeutic Potential of Stem Cells and their Secretory Products in Regenerative Medicine.

Cell therapy involves the transplantation of human cells to replace or repair the damaged tissues and modulate the mechanisms underlying disease initiation and progression in the body. Nowadays, many different types of cell-based therapy are developed and used to treat a variety of diseases. In the past decade, cell-free therapy has emerged as a novel approach in regenerative medicine after the discovery that the transplanted cells exerted their therapeutic effect mainly through the secretion of paracrine factors. More and more evidence showed that stem cell-derived secretome, i.e., growth factors, cytokines, and extracellular vesicles, can repair the injured tissues as effectively as the cells. This finding has spurred a new idea to employ secretome in regenerative medicine. Despite that, will cell-free therapy slowly replace cell therapy in the future? Or are these two modes of treatment still needed to address different diseases and conditions? This review provides an indepth discussion about the values of stem cells and secretome in regenerative medicine. In addition, the safety, efficacy, advantages, and disadvantages of using these two modes of treatment in regenerative medicine are also critically reviewed.

Collagen-coated polylactic-glycolic acid (PLGA) seeded with neural-differentiated human mesenchymal stem cells as a potential nerve conduit.

BACKGROUND: Autologous nerve grafts to bridge nerve gaps pose various drawbacks. Nerve tissue engineering to promote nerve regeneration using artificial neural conduits has emerged as a promising alternative. OBJECTIVES: To develop an artificial nerve conduit using collagen-coated polylactic-glycolic acid (PLGA) and to analyse the survivability and propagating ability of the neuro-differentiated human mesenchymal stem cells in this conduit. MATERIAL AND METHODS: The PLGA conduit was constructed by dip-molding method and coated with collagen by immersing the conduit in collagen bath. The ultra structure of the conduits were examined before they were seeded with neural-differentiated human mesenchymal stem cells (nMSC) and implanted sub-muscularly on nude mice thighs. The non-collagen-coated PLGA conduit seeded with nMSC and non-seeded non-collagen-coated PLGA conduit were also implanted for comparison purposes. The survivability and propagation ability of nMSC was studied by histological and immunohistochemical analysis. RESULTS: The collagen-coated conduits had a smooth inner wall and a highly porous outer wall. Conduits coated with collagen and seeded with nMSCs produced the most number of cells after 3 weeks. The best conduit based on the number of cells contained within it after 3 weeks was the collagen-coated PLGA conduit seeded with neuro-transdifferentiated cells. The collagen-coated PLGA conduit found to be suitable for attachment, survival and proliferation of the nMSC. Minimal cell infiltration was found in the implanted conduits where nearly all of the cells found in the cell seeded conduits are non-mouse origin and have neural cell markers, which exhibit the biocompatibility of the conduits. CONCLUSIONS: The collagen-coated PLGA conduit is biocompatible, non-cytotoxic and suitable for use as artificial nerve conduits.

Neural-differentiated mesenchymal stem cells incorporated into muscle stuffed vein scaffold forms a stable living nerve conduit.

Autologous nerve grafts to bridge nerve gaps have donor site morbidity and possible neuroma formation resulting in development of various methods of bridging nerve gaps without using autologous nerve grafts. We have fabricated an acellular muscle stuffed vein seeded with differentiated mesenchymal stem cells (MSCs) as a substitute for nerve autografts. Human vein and muscle were both decellularized by liquid nitrogen immersion with subsequent hydrolysis in hydrochloric acid. Human MSCs were subjected to a series of treatments with a reducing agent, retinoic acid, and a combination of trophic factors. The differentiated MSCs were seeded on the surface of acellular muscle tissue and then stuffed into the vein. Our study showed that 35-75% of the cells expressed neural markers such as S100b, glial fibrillary acidic protein (GFAP), p75 NGF receptor, and Nestin after differentiation. Histological and ultra structural analyses of muscle stuffed veins showed attachment of cells onto the surface of the acellular muscle and penetration of the cells into the hydrolyzed fraction of muscle fibers. We implanted these muscle stuffed veins into athymic mice and at 8 weeks post-implantation, the acellular muscle tissue had fully degraded and replaced with new matrix produced by the seeded cells. The vein was still intact and no inflammatory reactions were observed proving the biocompatibility and biodegradability of the conduit. In conclusion, we have successfully formed a stable living nerve conduit which may serve as a substitute for autologous nerves.