Evaluation of the efficacy of platelet-rich plasma in delivering BMSCs into 3D porous scaffolds

Study of platelet-rich fibrin promoting endothelial cell differentiation and angiogenesis induced by transplantation of adipose-derived stem cells

Diabetic patients are characterized by long wound healing time, and adipose stem cells (ADSCs) can secrete growth factors to promote angiogenesis and improve diabetic wound healing. In this research, we attempted to interrogate the impact of platelet-rich fibrin (PRF) on ADSCs in diabetic wound healing. ADSCs were harvested from human adipose tissues and identified through flow cytometry. After pretreatment with cultured medium supplemented with different concentrations of PRF (2.5%, 5%, and 7.5%), proliferation and differentiation capacity of ADSCs were assessed by CCK-8 assay, qRT-PCR and immunofluorescence (IF), respectively. Tube formation assay measured angiogenesis. Western blot analysis analyzed expression of endothelial markers and the extracellular signal-regulated kinase (ERK) and serine/threonine kinase (Akt) pathways in PRF-induced ADSCs. The CCK-8 experiment indicated that PRF enhanced proliferation of ADSCs in dose-dependent manner, relative to normal control group. The expression of endothelial markers and the capacity of tube formation were significantly promoted by 7.5% PRF. The release of growth factors containing vascular endothelial grow factor (VEGF) and insulin-like growth factor-1 (IGF-1) from PRF was increased with the extension of detection time. When the receptors of VEGF or/and IGF-1 were neutralized, ADSCs differentiation into endothelial cells were obviously inhibited. Additionally, PRF stimulated ERK and Akt pathways, and the inhibitors of ERK and Akt attenuated PRF-induced differentiation of ADSCs into endothelial cells. In conclusion, PRF promoted endothelial cell differentiation and angiogenesis induced by ADSCs in diabetic wound healing, which appears to give guidance for treating patients.

Mesenchymal Stem Cell Studies in the Goat Model for Biomedical Research—A Review of the Scientific Literature

Simple Summary

This review article aims to compile the works published in the scientific literature, over the last two decades, that use the goat as an animal model in preclinical studies using stem cells, alone or associated with biomaterials, for the treatment of injury or disease in divers organ systems. These preclinical studies are performed prior to human clinical trials for the implementation of new medical or surgical therapies in clinical practice. Thus, it appears that, in the area of tissue engineering and regenerative medicine, the caprine model is particularly used in studies using stem cells in the musculoskeletal system but, although in a more limited way, also in the field of dermatology, ophthalmology, dentistry, pneumology, cardiology, and urology. It appears that the goat represents a particularly useful animal model for studies related to the locomotor system because of its size, and also because they have a more active behavior than sheep, being more similar to the human species in this aspect. Additionally, the goat knee anatomy and the thickness of the cartilage that covers this joint are closer to that of humans than that of other large animal models commonly used in orthopedic research.

Abstract

Mesenchymal stem cells (MSCs) are multipotent cells, defined by their ability to self-renew, while maintaining the capacity to differentiate into different cellular lineages, presumably from their own germinal layer. MSCs therapy is based on its anti-inflammatory, immunomodulatory, and regenerative potential. Firstly, they can differentiate into the target cell type, allowing them to regenerate the damaged area. Secondly, they have a great immunomodulatory capacity through paracrine effects (by secreting several cytokines and growth factors to adjacent cells) and by cell-to-cell contact, leading to vascularization, cellular proliferation in wounded tissues, and reducing inflammation. Currently, MSCs are being widely investigated for numerous tissue engineering and regenerative medicine applications. Appropriate animal models are crucial for the development and evaluation of regenerative medicine-based treatments and eventual treatments for debilitating diseases with the hope of application in upcoming human clinical trials. Here, we summarize the latest research focused on studying the biological and therapeutic potential of MSCs in the goat model, namely in the fields of orthopedics, dermatology, ophthalmology, dentistry, pneumology, cardiology, and urology fields.

Berberine encapsulated in exosomes derived from platelet-rich plasma promotes chondrogenic differentiation of the Bone Marrow Mesenchymal Stem Cells via the Wnt/β-catenin pathway

Cartilage regenerative medicine, wherein the stem cells from adults exert a crucial role, has high potential in the treatment of defective articular cartilage. Recently, Bone marrow mesenchymal stem cells (BMSCs) are being increasingly recognized as an alternative source of adult stem cells, which are capable of differentiating into several cell types (e.g., adipocytes, chondrocytes, and osteoblasts). However, their proliferative properties and tendency to dedifferentiate restrict their use in clinical settings. Recently, a possible bioactive material PRP-exos (exosomes derived from platelet-rich plasma), has emerged, which can effectively facilitate the differentiation and proliferation of cells. Recent studies have reported that berberine (Ber), known to have anti-inflammatory properties, plays a role in osteogenesis. Since biological molecules are used in combinations, we attempted to assess the effect of Exos-Ber (PRP-exos in combination with Ber) on the chondrogenic differentiation of BMSCs in vitro. In this study, Exos-Ber was observed to promote the proliferation of BMSCs and cause their chondrogenic differentiation in vitro. Additionally, Exos-Ber could promote the migration of BMSCs and increase the protein expression of the chondrogenic genes (Collagen II, SOX9, Aggrecan). After treatment with Exos-Ber, significant induction of β-catenin expression was observed, which could be repressed successfully by adding β-catenin inhibitor XAV-939. Interestingly, the repression of the Wnt/β-catenin axis also resulted in reduced gene expression levels of Collagen II, SOX9, and Aggrecan. These observations indicated that Exos-Ber facilitated the differentiation of chondrogenic BMSCs by modulating the Wnt/β-catenin axis, which offers innovative insights into the reconstruction of cartilage.

Functionalising Collagen-Based Scaffolds With Platelet-Rich Plasma for Enhanced Skin Wound Healing Potential

Porous collagen-glycosaminoglycan (collagen-GAG) scaffolds have shown promising clinical results for wound healing; however, these scaffolds do not replace the dermal and epidermal layer simultaneously and rely on local endogenous signaling to direct healing. Functionalizing collagen-GAG scaffolds with signaling factors, and/or additional matrix molecules, could help overcome these challenges. An ideal candidate for this is platelet-rich plasma (PRP) as it is a natural reservoir of growth factors, can be activated to form a fibrin gel, and is available intraoperatively. We tested the factors released from PRP (PRPr) and found that at specific concentrations, PRPr enhanced cell proliferation and migration and induced angiogenesis to a greater extent than fetal bovine serum (FBS) controls. This motivated us to develop a strategy to successfully incorporate PRP homogeneously within the pores of the collagen-GAG scaffolds. The composite scaffold released key growth factors for wound healing (FGF, TGFβ) and vascularization (VEGF, PDGF) for up to 14 days. In addition, the composite scaffold had enhanced mechanical properties (when compared to PRP gel alone), while providing a continuous upper surface of extracellular matrix (ECM) for keratinocyte seeding. The levels of the factors released from the composite scaffold were sufficient to sustain proliferation of key cells involved in wound healing, including human endothelial cells, mesenchymal stromal cells, fibroblasts, and keratinocytes; even in the absence of FBS supplementation. In functional in vitro and in vivo vascularization assays, our composite scaffold demonstrated increased angiogenic and vascularization potential, which is known to lead to enhanced wound healing. Upon pro-inflammatory induction, macrophages released lower levels of the pro-inflammatory marker MIP-1α when treated with PRPr; and released higher levels of the anti-inflammatory marker IL1-ra upon both pro- and anti-inflammatory induction when treated with the composite scaffold. Finally, our composite scaffold supported a co-culture system of human fibroblasts and keratinocytes that resulted in an epidermal-like layer, with keratinocytes constrained to the surface of the scaffold; by contrast, keratinocytes were observed infiltrating the PRP-free scaffold. This novel composite scaffold has the potential for rapid translation to the clinic by isolating PRP from a patient intraoperatively and combining it with regulatory approved scaffolds to enhance wound repair.

Platelet Metabolism and Other Targeted Drugs; Potential Impact on Immunotherapy

The role of platelets in cancer progression has been well recognized in the field of cancer biology. Emerging studies are elaborating further the additional roles and added extent that platelets play in promoting tumorigenesis. Platelets release factors that support tumor growth and also form heterotypic aggregates with tumor cells, which can provide an immune-evasive advantage. Their most critical role may be the inhibition of immune cell function that can negatively impact the body’s ability in preventing tumor establishment and growth. This review summarizes the importance of platelets in tumor progression, therapeutic response, survival, and finally the notion of immunotherapy modulation being likely to benefit from the inclusion of platelet inhibitors.

Differentiation of Human Scalp Adipose-Derived Mesenchymal Stem Cells into Mature Neural Cells on Electrospun Nanofibrous Scaffolds for Nerve Tissue Engineering Applications

Objective

This study aimed to isolate and culture SADS cells, investigate their neurogenic capacity and evaluate their application for nerve tissue engineering.

Materials and Methods

In this experimental study, SADS cells were isolated from human adipose tissue. After 7-day treatment of SADS cells with insulin, indomethacin and isobutylmethylxanthine, neurogenic differentiation of SADS cells was investigated. During this study, Poly (ε-caprolactone) (PCL) and PCL/gelatin nanofibrous scaffolds were fabricated using electrospinning and subsequently nanofibrous scaffolds were coated with platelet-rich plasma (PRP). SADS cells were also seeded on nanofibrous scaffolds and neurogentic differentiation of these cells on nanofibers was also evaluated. Effect of PRP on proliferation and differentiation of SADS cells on scaffolds was also studied.

Results

Our results showed that after 7-day treatment of SADS cells with insulin, indomethacin and isobutylmethylxanthine, SADS cells expressed markers characteristic of neural cells such as nestin and neuron specific nuclear protein (NEUN) (as early neuronal markers) as well as microtubule-associated protein 2 (MAP2) and neuronal microtubule-associated (TAU) (as mature neuronal markers) while mature astrocyte maker (GFAP) was not expressed. MTT assay and SEM results showed that incorporation of gelatin and PRP into the structure of nanofibrous scaffolds has a significant positive influence on the bioactivity of scaffolds. Our results also showed neurogentic differentiation of SADS cells on scaffolds.

Conclusion

Our results demonstrated that SADS cells have potential to differentiate into early and mature progenitor neurons, in vitro. PCL/gelatin/PRP was found to be a promising substrate for proliferation of SADS cells and differentiation of these cells into neural cells which make these scaffolds a candidate for further in vivo experiments and suggest their application for nerve tissue engineering.

Application of platelet-rich plasma with stem cells in bone and periodontal tissue engineering

Presently, there is a high paucity of bone grafts in the United States and worldwide. Regenerating bone is of prime concern due to the current demand of bone grafts and the increasing number of diseases causing bone loss. Autogenous bone is the present gold standard of bone regeneration. However, disadvantages like donor site morbidity and its decreased availability limit its use. Even allografts and synthetic grafting materials have their own limitations. As certain specific stem cells can be directed to differentiate into an osteoblastic lineage in the presence of growth factors (GFs), it makes stem cells the ideal agents for bone regeneration. Furthermore, platelet-rich plasma (PRP), which can be easily isolated from whole blood, is often used for bone regeneration, wound healing and bone defect repair. When stem cells are combined with PRP in the presence of GFs, they are able to promote osteogenesis. This review provides in-depth knowledge regarding the use of stem cells and PRP in vitro, in vivo and their application in clinical studies in the future.

The use of platelet-rich plasma in plastic surgery: a systematic review

OBJECTIVE

The study's aim was to evaluate the available evidence regarding the use of platelet-rich plasma in plastic and reconstructive surgery, through implementation of a systematic review of the literature.

DATA SOURCES

PubMed and The Cochrane Library were searched using MeSH terms: 'platelet rich plasma' and 'plastic surgery' for all publications up to July 2011. All English, German, French and Dutch papers were included. In addition, the reference lists of relevant articles were searched for potentially appropriate publications.

STUDY SELECTION

Included studies needed to report on topics related to plastic and reconstructive surgery, mentioning at least one clinical end point. Both in vivo and in vitro comparative studies, performed in humans or animals, were included. A total of 82 publications were found, of which 40 studies met the inclusion criteria and were relevant to be used in this systematic review.

DATA EXTRACTION

Data from retrieved studies were reviewed and tabulated according to year of publication, study design, human or animal studies, characteristics of the population, mode of application, outcomes and preparation method.

DATA SYNTHESIS

A total of 15 randomised controlled trials and 25 case-control studies were found. Thirty-six publications demonstrated favourable outcomes with the use of platelet-rich plasma. The included articles were divided into three topics related to plastic surgery: wound healing, fat grafting and bone grafting.

CONCLUSIONS

This systematic review describes a substantially beneficial effect of platelet-rich plasma for several indications, including a better wound healing rate, an increased survival rate of fat grafts and an enhancement of bone graft regeneration.

Sustained delivery of BMP-2 and platelet-rich plasma-released growth factors contributes to osteogenesis of human adipose-derived stem cells

Platelet-rich plasma (PRP) has a pool of multiple growth factors efficient at inducing the proliferation and osteogenic differentiation of human adipose-derived stem cells (hADSCs). Bone morphogenetic protein (BMP)-2 is a strong stimulator for the osteogenic differentiation of hADSCs. The purpose of this study was to verify the effect of PRP-released growth factors and microsphere-encapsulated BMP-2 on the proliferation and osteoblastic differentiation of hADSCs and to construct a novel tissue-engineered bone. The BMP-2-loaded microspheres and hADSCs were embedded in activated PRP gel. Another 5 composites (hADSCs/platelet-poor plasma [PPP]; hADSCs/PRP; hADSCs/BMP-2/PPP; hADSCs/BMP-2/PRP; and hADSCs/BMP-2+microspheres/PPP) were also constructed. The DNA content, alkaline phosphatase activity, mRNA expression of alkaline phosphatase, osteopontin, osteocalcin, and mineralization of hADSCs in each composite were compared. The DNA content was higher in all PRP-containing composites, meaning that PRP-released growth factors stimulated proliferation of hADSCs. Alkaline phosphatase increased in BMP-2/PRP and BMP-2+microspheres/PRP composites in the first 7 days, meaning that BMP-2 had a synergistic effect with PRP in the early differentiation of hADSCs. Osteopontin, osteocalcin, and mineralization assays were higher in BMP-2+microspheres/PRP composite than in the BMP-2/PRP composite up to 21 days, meaning that a continuous delivery of BMP-2 stimulates osteoblastic differentiation of hADSCs at the early stage and the final maturation stage. These results suggest that sustained delivery of BMP-2 in combination with PRP is better than a single administration of PRP or BMP-2 in the osteogenic differentiation of hADSCs.

Incorporating platelet-rich plasma into electrospun scaffolds for tissue engineering applications

Platelet-rich plasma (PRP) therapy has seen a recent spike in clinical interest due to the potential that the highly concentrated platelet solutions hold for stimulating tissue repair and regeneration. The aim of this study was to incorporate PRP into a number of electrospun materials to determine how growth factors are eluted from the structures, and what effect the presence of these factors has on enhancing electrospun scaffold bioactivity. PRP underwent a freeze-thaw-freeze process to lyse platelets, followed by lyophilization to create a powdered preparation rich in growth factors (PRGF), which was subsequently added to the electrospinning process. Release of protein from scaffolds over time was quantified, along with the quantification of human macrophage and adipose-derived stem cell (ADSC) chemotaxis and proliferation. Protein assays demonstrated a sustained release of protein from PRGF-containing scaffolds at up to 35 days in culture. Scaffold bioactivity was enhanced as ADSCs demonstrated increased proliferation in the presence of PRGF, whereas macrophages demonstrated increased chemotaxis to PRGF. In conclusion, the work performed in this study demonstrated that the incorporation of PRGF into electrospun structures has a significant positive influence on the bioactivity of the scaffolds, and may prove beneficial in a number of tissue engineering applications.

Perspectives and challenges in regenerative medicine using plasma rich in growth factors

Plasma rich in growth factors (PRGF-Endoret) is an endogenous therapeutic technology that is gaining interest in regenerative medicine due to its potential to stimulate and accelerate tissue healing and bone regeneration. This autologous biotechnology is designed for the in situ delivery of multiple cellular modulators and the formation of a fibrin scaffold, thereby providing different formulations that can be widely used in numerous medical and scientific fields including dentistry, oral implantology, orthopedics, ulcer treatment and tissue engineering among others. Here we discuss the important progress that has been accomplished in this field. Furthermore, a comprehensive outlook of the intriguing therapeutic applications of this technology is presented.

Uncultured marrow mononuclear cells delivered within fibrin glue hydrogels to porous scaffolds enhance bone regeneration within critical-sized rat cranial defects

For bone tissue engineering, the benefits of incorporating mesenchymal stem cells (MSCs) into porous scaffolds are well established. There is, however, little consensus on the effects of or need for MSC handling ex vivo. Culture and expansion of MSCs adds length and cost, and likely increases risk associated with treatment. We evaluated the effect of using uncultured bone marrow mononuclear cells (bmMNCs) encapsulated within fibrin glue hydrogels and seeded into porous scaffolds to regenerate bone over 12 weeks in an 8-mm-diameter, critical-sized rat cranial defect. A full factorial experimental design was used to evaluate bone formation within model poly(L-lactic acid) and corraline hydroxyapatite scaffolds with or without platelet-rich plasma (PRP) and bmMNCs. Mechanical push-out testing, microcomputed tomographical analyses, and histology were performed. PRP showed no benefit for bone formation. Cell-laden poly(L-lactic acid) scaffolds without PRP required significantly greater force to displace from surrounding tissues than control (cell-free) scaffolds, but no differences were observed during push-out testing of coral scaffolds. For bone volume formation as analyzed by microcomputed tomography, significant positive overall effects were observed with bmMNC incorporation. These data suggest that bmMNCs may provide therapeutic advantages in bone tissue engineering applications without the need for culture, expansion, and purification.