Platelet-rich plasma and alignment enhance myogenin via ERK mitogen activated protein kinase signaling

Autologous Bioactive Compound Concentrated Growth Factor Ameliorates Fistula Healing of Anal Fistula in a Pig Model and Promotes Proliferation and Migration of Human Skin Fibroblasts via Regulating the MEK/ERK Pathway

Recent evidence suggested that autologous concentrated growth factor (CGF), a new bioactive compound from autologous blood is used widely as an ingenious biomaterial in tissue regeneration with anti-inflammatory properties. This study investigated whether CGF could be involved in the treatment of fistula healing in the anal fistula. For this purpose, the porcine anal fistula model was conducted using the rubber band ligation method and collected pig autogenic CGF to treat the fistulas. CGF treatment promoted fistula healing, which was reflected in the downregulation of inflammatory factors, upregulation of growth factors, and promoted epithelial-mesenchymal transition with increased collagen synthesis. Besides, 16S rRNA gene sequencing analysis of fistula tissues between the control and CGF groups showed that the microbial populations exhibiting significant differences were VadinCA02, Blastomonas, Deinococcus, Devosia, Sphingomonas, Rubrobacteria, and GW_34. CGF of volunteers were collected to process small interfering RNA- (siRNA-) ERK or siRNA-negative control transfected human skin fibroblasts (HSF). The results showed that CGF also promoted the proliferation and extracellular matrix-related functions in HSF, as well as activated the MEK/ERK pathway in vitro and in vivo. Finally, knockdown ERK reversed the effects of CGF in promoting wound healing in HSF. Collectively, our results suggest that the CGF as the bioactive compound from autologous blood exhibited great potential for repairing fistulas as well as promoting the proliferation and migration of human skin fibroblasts by triggering MEK/ERK signaling. These findings provided a fresh perspective for understanding the role of CGF in the management of fistulas.

Minimally invasive co-injection of modular micro-muscular and micro-vascular tissues improves in situ skeletal muscle regeneration

Various conventional treatment strategies for volumetric muscle loss (VML) are often hampered by the extreme donor site morbidity, the limited availability of quality muscle flaps, and complicated, as well as invasive surgical procedures. The conventional biomaterial-based scaffolding systems carrying myoblasts have been extensively investigated towards improving the regeneration of the injured muscle tissues, as well as their injectable forms. However, the applicability of such designed systems has been restricted due to the lack of available vascular networks. Considering these facts, here we present the development of a unique set of two minimally invasively injectable modular microtissues, consisting of mouse myoblast (C2C12)-laden poly(lactic-co-glycolic acid) porous microspheres (PLGA PMs), or the micro-muscles, and human umbilical vein endothelial cell (HUVEC)-laden poly(ethylene glycol) hollow microrods (PEG HMs), or the microvessels. Besides systematic in vitro investigations, the myogenic performance of these modular composite microtissues, when co-injected, was explored in vivo using a mouse VML model, which confirmed improved in situ muscle regeneration and remolding. Together, we believe that the construction of these injectable modular microtissues and their combination for minimally invasive therapy provides a promising method for in situ tissue healing.

Freeze-Drying of Platelet-Rich Plasma: The Quest for Standardization

The complex biology of platelets and their involvement in tissue repair and inflammation have inspired the development of platelet-rich plasma (PRP) therapies for a broad array of medical needs. However, clinical advances are hampered by the fact that PRP products, doses and treatment protocols are far from being standardized. Freeze-drying PRP (FD-PRP) preserves platelet function, cytokine concentration and functionality, and has been proposed as a consistent method for product standardization and fabrication of an off-the-shelf product with improved stability and readiness for future uses. Here, we present the current state of experimental and clinical FD-PRP research in the different medical areas in which PRP has potential to meet prevailing medical needs. A systematic search, according to PRISMA (Preferred Reported Items for Systematic Reviews and Meta-Analyses) guidelines, showed that research is mostly focused on wound healing, i.e., developing combination products for ulcer management. Injectable hydrogels are investigated for lumbar fusion and knee conditions. In dentistry, combination products permit slow kinetics of growth factor release and functionalized membranes for guided bone regeneration.

Influence of Platelet-Rich and Platelet-Poor Plasma on Endogenous Mechanisms of Skeletal Muscle Repair/Regeneration

The morpho-functional recovery of injured skeletal muscle still represents an unmet need. None of the therapeutic options so far adopted have proved to be resolutive. A current scientific challenge remains the identification of effective strategies improving the endogenous skeletal muscle regenerative program. Indeed, skeletal muscle tissue possesses an intrinsic remarkable regenerative capacity in response to injury, mainly thanks to the activity of a population of resident muscle progenitors called satellite cells, largely influenced by the dynamic interplay established with different molecular and cellular components of the surrounding niche/microenvironment. Other myogenic non-satellite cells, residing within muscle or recruited via circulation may contribute to post-natal muscle regeneration. Unfortunately, in the case of extended damage the tissue repair may become aberrant, giving rise to a maladaptive fibrotic scar or adipose tissue infiltration, mainly due to dysregulated activity of different muscle interstitial cells. In this context, plasma preparations, including Platelet-Rich Plasma (PRP) and more recently Platelet-Poor Plasma (PPP), have shown advantages and promising therapeutic perspectives. This review focuses on the contribution of these blood-derived products on repair/regeneration of damaged skeletal muscle, paying particular attention to the potential cellular targets and molecular mechanisms through which these products may exert their beneficial effects.