Platelet-Rich Plasma Increases Growth and Motility of Adipose Tissue-Derived Mesenchymal Stem Cells and Controls Adipocyte Secretory Function

PHAT Lips and PHAT Face: Platelet Hybridized Adipose Therapy for Superficial Musculoaponeurotic System and Dermal Rejuvenation

Platelet-rich plasma has been increasingly used for facial rejuvenation in conjunction with other modalities such as microneedling or on its own. Nanofat grafting to the face has also been utilized for skin quality improvements. Our group previously described the novel combined Platelet Hybridized Adipose Transplant (PHAT) technique for hair restoration. In this series, we describe our experience with the PHAT technique for lip and facial rejuvenation to improve the quality of facial skin and superficial musculoaponeurotic system, and enhancing surgical results.

The Effectiveness and Safety of Autologous Platelet Concentrates as Hemostatic Agents after Tooth Extraction in Patients on Anticoagulant Therapy: A Systematic Review of Randomized, Controlled Trials

One of the common challenges in oral surgery is dealing with patients who are taking oral anticoagulant/antiaggregant drugs. Several local hemostatic agents have been proposed as an alternative to conventional suturing. Among these, autologous platelet concentrates (APCs) have been widely used to decrease the risk of hemorrhage after dental extraction. Nevertheless, there is a lack of consensus regarding the superiority of any one specific hemostatic agent over the others. This systematic review is aimed at evaluating the effectiveness of APCs as hemostatic agents after tooth extraction in patients on anticoagulant therapy. A literature search was conducted of articles published before March 2023 on PubMed, Scopus, and the Cochrane Central Register of Controlled Trials (CENTRAL). Studies on the use of APCs in patients undergoing dental extractions and being treated with anticoagulant drugs were included. Only randomized, controlled trials (RCTs) published up to March 2023 were included; the outcomes assessed were the time to hemostasis, the presence of post-operative bleeding and pain, and the effectiveness of wound healing. The risk of bias for each RCT was assessed by using the 'risk of bias' tool (RoB 1.0). The research revealed 6 RCTs. The findings indicated that patients on anticoagulant therapy who received APCs without discontinuing their medication experienced a decreased post-operative bleeding, a shorter hemostasis time, reduced pain, and accelerated wound healing. However, due to the high/unclear risk of bias of the studies included, no definitive conclusions can be drawn on the superiority of APCs as hemostatic agents over other similar products. Additional studies are required to validate these findings.

Human Platelet-Rich Plasma Regulates Canine Mesenchymal Stem Cell Migration through Aquaporins

Platelet products are commonly used in regenerative medicine due to their effects on the acceleration and promotion of wound healing, reduction of bleeding, synthesis of new connective tissue, and revascularization. Furthermore, a novel approach for the treatment of damaged tissues, following trauma or other pathological damages, is represented by the use of mesenchymal stem cells (MSCs). In dogs, both platelet-rich plasma (PRP) and MSCs have been suggested to be promising options for subacute skin wounds. However, the collection of canine PRP is not always feasible. In this study, we investigated the effect of human PRP (hPRP) on canine MSCs (cMSCs). We isolated cMSCs and observed that hPRP did not modify the expression levels of the primary class of major histocompatibility complex genes. However, hPRP was able to increase cMSC viability and migration by at least 1.5-fold. hPRP treatment enhanced both Aquaporin (AQP) 1 and AQP5 protein levels, and their inhibition by tetraethylammonium chloride led to a reduction of PRP-induced migration of cMSCs. In conclusion, we have provided evidence that hPRP supports cMSC survival and may promote cell migration, at least through AQP activation. Thus, hPRP may be useful in canine tissue regeneration and repair, placing as a promising tool for veterinary therapeutic approaches.

Platelet-Derived Mitochondria Attenuate 5-FU-Induced Injury to Bone-Associated Mesenchymal Stem Cells

Background

Myelosuppression is a common condition during chemotherapy. Bone-associated mesenchymal stem cells (BA-MSCs) play an essential role in the composition of the hematopoietic microenvironment and support hematopoietic activity. However, chemotherapy-induced damage to BA-MSCs is rarely studied. Recent studies have shown that platelets promote the wound-healing capability of MSCs by mitochondrial transfer. Therefore, this study is aimed at investigating the chemotherapy-induced damage to BA-MSCs and the therapeutic effect of platelet-derived mitochondria. Material/Methods. We established in vivo and in vitro BA-MSC chemotherapy injury models using the chemotherapy agent 5-fluorouracil (5-FU). Changes in the mitochondrial dynamics were detected by transmission electron microscopy, and the expression of mitochondrial fusion and fission genes was analyzed by qRT-PCR. In addition, mitochondrial functions were also explored by flow cytometry and luminometer. Platelet-derived mitochondria were incubated with 5-FU-damaged BA-MSCs to repair the injury, and BA-MSC functional changes were examined to assess the therapy efficacy. The mechanism of treatment was explored by studying the expression of mitochondrial fission and fusion genes and hematopoietic regulatory factor genes in BA-MSCs.

Results

Stimulation with 5-FU increased the apoptosis and suppressed cell cycle progression of BA-MSCs both in vivo and in vitro. In addition, 5-FU chemotherapy inhibited the hematopoietic regulatory ability and disrupted the mitochondrial dynamics and functions of BA-MSCs. The mitochondrial membrane potential and ATP content of 5-FU-injured BA-MSCs were decreased. Interestingly, when platelet-derived mitochondria were transferred to BA-MSCs, the 5-FU-induced apoptosis was alleviated, and the hematopoietic regulatory ability of 5-FU-injured BA-MSCs was effectively improved by upregulating the expression of mitochondrial fusion genes and hematopoietic regulatory factor genes.

Conclusion

BA-MSCs were severely damaged by 5-FU chemotherapy both in vivo and in vitro. Meanwhile, platelet-derived mitochondria could attenuate the 5-FU-induced injury to BA-MSCs, which provides future research directions for exploring the treatment strategies for chemotherapy-injured BA-MSCs and establishes a research basis for related fields.

Autologous Adipose-Derived Tissue Stromal Vascular Fraction (AD-tSVF) for Knee Osteoarthritis

Adipose tissue contains adult mesenchymal stem cells that may modulate the metabolism when applied to other tissues. Stromal vascular fraction (SVF) can be isolated from adipose tissue mechanically and/or enzymatically. SVF was recently used to decrease the pain and improve the function of knee osteoarthritis (OA) patients. Primary and/or secondary OA causes inflammation and degeneration in joints, and regenerative approaches that may modify the natural course of the disease are limited. SVF may modulate inflammation and initiate regeneration in joint tissues by initiating a paracrine effect. Chemokines released from SVF may slow down degeneration and stimulate regeneration in joints. In this review, we overviewed articular joint cartilage structures and functions, OA, and macro-, micro-, and nano-fat isolation techniques. Mechanic and enzymatic SVF processing techniques were summarized. Clinical outcomes of adipose tissue derived tissue SVF (AD-tSVF) were evaluated. Medical devices that can mechanically isolate AD-tSVF were listed, and publications referring to such devices were summarized. Recent review manuscripts were also systematically evaluated and included. Transferring adipose tissues and cells has its roots in plastic, reconstructive, and aesthetic surgery. Micro- and nano-fat is also transferred to other organs and tissues to stimulate regeneration as it contains regenerative cells. Minimal manipulation of the adipose tissue is recently preferred to isolate the regenerative cells without disrupting them from their natural environment. The number of patients in the follow-up studies are recently increasing. The duration of follow up is also increasing with favorable outcomes from the short- to mid-term. There are however variations for mean age and the severity of knee OA patients between studies. Positive outcomes are related to the higher number of cells in the AD-tSVF. Repetition of injections and concomitant treatments such as combining the AD-tSVF with platelet rich plasma or hyaluronan are not solidified. Good results were obtained when combined with arthroscopic debridement and micro- or nano-fracture techniques for small-sized cartilage defects. The optimum pressure applied to the tissues and cells during filtration and purification of the AD-tSVF is not specified yet. Quantitative monitoring of articular joint cartilage regeneration by ultrasound, MR, and synovial fluid analysis as well as with second-look arthroscopy could improve our current knowledge on AD-tSVF treatment in knee OA. AD-tSVF isolation techniques and technologies have the potential to improve knee OA treatment. The duration of centrifugation, filtration, washing, and purification should however be standardized. Using gravity-only for isolation and filtration could be a reasonable approach to avoid possible complications of other methodologies.

Characterization of Migratory Cells From Bioengineered Bovine Cartilage in a 3D Co-culture Model

BACKGROUND

Chondrocyte migration in native cartilage is limited and has been implicated as one of the reasons for the poor integration of native implants. Through use of an in vitro integration model, it has previously been shown that cells from bioengineered cartilage can migrate into the native host cartilage during integration. Platelet-rich plasma (PRP) treatment further enhanced integration of bioengineered cartilage to native cartilage in vitro. However, it is not known how PRP treatment of the bioengineered construct promotes this.

HYPOTHESIS

PRP supports cell migration from bioengineered cartilage and these migratory cells have the ability to accumulate cartilage-like matrix.

STUDY DESIGN

Controlled laboratory study.

METHODS

Osteochondral-like constructs were generated by culturing primary bovine chondrocytes on the top surface of a porous bone substitute biomaterial composed of calcium polyphosphate. After 1 week in culture, the constructs were submerged in PRP and placed adjacent, but 2 mm distant, to a native bovine osteochondral plug in a co-culture model for 2 weeks. Cell migration was monitored using phase-contrast imaging. Cell phenotype was determined by evaluating the gene expression of matrix metalloprotease 13 (MMP-13), Ki67, and cartilage matrix molecules using quantitative polymerase chain reaction. When tissue formed, it was assessed by histology, immunohistochemistry, and quantification of matrix content.

RESULTS

PRP treatment resulted in the formation of a fiber network connecting the bioengineered cartilage and native osteochondral plug. Cells from both the bioengineered cartilage and the native osteochondral tissue migrated onto the PRP fibers and formed a tissue bridge after 2 weeks of culture. Migratory cells on the tissue bridge expressed higher levels of collagen types II and I (COL2, COL1), Ki67 and MMP-13 mRNA compared with nonmigratory cells in the bioengineered cartilage. Ki67 and MMP-13-positive cells were found on the edges of the tissue bridge. The tissue bridge accumulated COL1 and COL2 and aggrecan and contained comparable collagen and glycosaminoglycan content to the bioengineered cartilage matrix. The tissue bridge did not reliably develop in the absence of cells from the native osteochondral plug.

CONCLUSION

Bioengineered cartilage formed by bovine chondrocytes contains cells that can migrate on PRP fibers and form cartilaginous tissue.

CLINICAL RELEVANCE

Migratory cells from bioengineered cartilage may promote cartilage integration. Further studies are required to determine the role of migratory cells in integration in vivo.

Nanofat: A therapeutic paradigm in regenerative medicine

Adipose tissue is a compact and well-organized tissue containing a heterogeneous cellular population of progenitor cells, including mesenchymal stromal cells. Due to its availability and accessibility, adipose tissue is considered a “stem cell depot.” Adipose tissue products possess anti-inflammatory, anti-fibrotic, anti-apoptotic, and immunomodulatory effects. Nanofat, being a compact bundle of stem cells with regenerative and tissue remodeling potential, has potential in translational and regenerative medicine. Considering the wide range of applicability of its reconstructive and regenerative potential, the applications of nanofat can be used in various disciplines. Nanofat behaves on the line of adipose tissue-derived mesenchymal stromal cells. At the site of injury, these stromal cells initiate a site-specific reparative response comprised of remodeling of the extracellular matrix, enhanced and sustained angiogenesis, and immune system modulation. These properties of stromal cells provide a platform for the usage of regenerative medicine principles in curbing various diseases. Details about nanofat, including various preparation methods, characterization, delivery methods, evidence on practical applications, and ethical concerns are included in this review. However, appropriate guidelines and preparation protocols for its optimal use in a wide range of clinical applications have yet to be standardized.

Effect of biomolecules derived from human platelet-rich plasma on the ex vivo expansion of human adipose-derived mesenchymal stem cells for clinical applications

Mesenchymal stem cells are a tool in cell therapies but demand a large cell number per treatment, for that, suitable culture media is required which contains fetal bovine serum (FBS). However, for cell-based therapy applications, the use of FBS is problematic. Several alternatives to FBS have been explored, including human derivatives from platelet-rich plasma (hD-PRP). Although various studies have evaluated the impact of hD-PRP on MSC proliferation and differentiation, few of them have assessed their influence on processes, such as metabolism and gene expression. Here, we cultured human adipose-derived MSCs (hAD-MSCs) in media supplemented with either 10% hD-PRP (hD-PRP-SM) or 10% FBS (FBS-SM) in order to characterize them and evaluate the effect of hD-PRP on cell metabolism, gene expression of associated regenerative factors, as well as chromosome stability during cell expansion. We found that hAD-MSCs cultured in hD-PRP-SM have a greater cell elongation but express similar surface markers; in addition, hD-PRP-SM promoted a significant osteogenic differentiation in the absence of differentiation medium and increased the growth rate, maintaining chromosomal stability. In terms of cell metabolic profile, hAD-MSC behavior did not reveal any differences between both culture conditions. Conversely, significant differences in collagen I and angiopoietin 2 expression were observed between both conditions. The present results suggest that hD-PRP may influence hAD-MSC behavior.

Translational products of adipose tissue-derived mesenchymal stem cells: Bench to bedside applications

With developments in the field of tissue engineering and regenerative medicine, the use of biological products for the treatment of various disorders has come into the limelight among researchers and clinicians. Among all the available biological tissues, research and exploration of adipose tissue have become more robust. Adipose tissue engineering aims to develop by-products and their substitutes for their regenerative and immunomodulatory potential. The use of biodegradable scaffolds along with adipose tissue products has a major role in cellular growth, proliferation, and differentiation. Adipose tissue, apart from being the powerhouse of energy storage, also functions as the largest endocrine organ, with the release of various adipokines. The progenitor cells among the heterogeneous population in the adipose tissue are of paramount importance as they determine the capacity of regeneration of these tissues. The results of adipose-derived stem-cell assisted fat grafting to provide numerous growth factors and adipokines that improve vasculogenesis, fat graft integration, and survival within the recipient tissue and promote the regeneration of tissue are promising. Adipose tissue gives rise to various by-products upon processing. This article highlights the significance and the usage of various adipose tissue by-products, their individual characteristics, and their clinical applications.

Effect of Activated Platelet-Rich Plasma on Chondrogenic Differentiation of Rabbit Bone Marrow-Derived Mesenchymal Stem Cells

We aimed to evaluate the effect of activated platelet-rich plasma (PRP) on proliferation and chondrogenic differentiation of bone marrow-derived mesenchymal stem cells (BMSCs). Six mature male rabbits were included in this study. PRP was obtained by two-step centrifugation from whole blood, and it was activated using CaCl₂ solution. BMSCs were isolated and proliferated from bone marrow of rabbits and characterized by flow cytometry. Passage 3 BMSCs were cultured in high-glucose Dulbecco's modified Eagle's medium (HG-DMEM) with the four different compositions for consecutive 7 days, including 10% fetal bovine serum, 5% PRP, 10% PRP, and 15% PRP. Cell counting assays were performed to evaluate the cell proliferation of BMSCs. BMSCs (5 × 10⁵ cells/well in 6-well plates) were induced in four conditions for 21 days to chondrogenic differentiation evaluation, including commercial chondrogenic medium (control), 5% PRP (HG-DMEM+5% PRP), 10% PRP (HG-DMEM+10% PRP), and 15% PRP (HG-DMEM+15% PRP). The gene expression levels of ACAN, COL2A1, and SOX9 in pellets were detected. Morphological and pathological assessments were performed by the blind observer. After purifying, the percentages of cells with CD105(+)/CD34(-) and CD44(+)/CD45(-) were 96.5% and 92.9%, respectively. The proliferation of BMSCs was enhanced in all groups, and 10% PRP revealed more significant outcome than the others from day 5. The levels of ACAN, COL2A1, and SOX9 were lower in the three PRP groups than control group, but the levels of ACAN and SOX9 were higher in 10% PRP group than 5% and 15% PRP groups. Histological examinations showed that 10% PRP-treated pellets had more regular appearance, larger size, and abundant extracellular matrix than 5% or 10% PRP groups, but still inferior to commercial chondrogenic medium. In conclusion, our results show that PRP may enhance the proliferation of rabbit BMSCs. However, PRP have limited effect on chondrogenic differentiation in comparison with commercial chondrogenic medium in pellets culture.

Education Technology in Orthodontics and Paediatric Dentistry during the COVID-19 Pandemic: A Systematic Review

Over the last decade, medical education changed from traditional teaching methods to telematic and networking scholar and e-learning approach. The objective of the present systematic review was to evaluate the effectiveness and teachers/student's acceptability of e-learning applied to the field of orthodontics and paediatric dentistry. A database search of the literature was conducted on PubMed and Embase databases from January 2005 to May 2021. A total of 172 articles were identified by the electronic search, while a total of 32 papers were selected for qualitative analysis. Overall, 19 articles investigated the effectiveness of e-learning, and no difference of acceptability was reported between e-learning and traditional methods for a wide part of the articles selected. A total of 25 papers provided a satisfaction questionnaire for learners and all were positive in their attitude towards e-learning. The results showed that e-learning is an effective method of instruction, complementing the traditional teaching methods, and learners had a positive attitude and perception. The evidence of the present study reported a high level of acceptability and knowledge level of e-learning techniques, compared to frontal lecture methods, in the fields of orthodontics and paediatric dentistry.

The 15-Months Clinical Experience of SARS-CoV-2: A Literature Review of Therapies and Adjuvants

BACKGROUND

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the virus responsible for the coronavirus disease of 2019 (COVID-19) that emerged in December 2019 in Wuhan, China, and rapidly spread worldwide, with a daily increase in confirmed cases and infection-related deaths. The World Health Organization declared a pandemic on the 11th of March 2020. COVID-19 presents flu-like symptoms that become severe in high-risk medically compromised subjects. The aim of this study was to perform an updated overview of the treatments and adjuvant protocols for COVID-19.

METHODS

A systematic literature search of databases was performed (MEDLINE PubMed, Google Scholar, UpToDate, Embase, and Web of Science) using the keywords: "COVID-19", "2019-nCoV", "coronavirus" and "SARS-CoV-2" (date range: 1 January 2019 to 31st October 2020), focused on clinical features and treatments.

RESULTS

The main treatments retrieved were antivirals, antimalarials, convalescent plasma, immunomodulators, corticosteroids, anticoagulants, and mesenchymal stem cells. Most of the described treatments may provide benefits to COVID-19 subjects, but no one protocol has definitively proven its efficacy.

CONCLUSIONS

While many efforts are being spent worldwide in research aimed at identifying early diagnostic methods and evidence-based effective treatments, mass vaccination is thought to be the best option against this disease in the near future.

Effects of Xenogen Mesenchymal Stem Cells and Cryo-Platelet Gel on Intractable Wound Healing in Animal

BACKGROUND

Today, the effects of growth factors and mesenchymal stem cells (MSCs) in promoting wound healing have been confirmed.

OBJECTIVE

This study aimed to investigate the effect of MSCs and platelet cryogel on wound healing.

METHODS

40 male Wistar rats were randomly divided into five groups (n=8). The control group just dressed, the second group received platelet cryogel, the third group received platelet cryogel containing MSCs, the fourth group received plasma, and the fifth group received plasma plus MSCs. The biopsy was obtained from the wounds in 2, 4, 6, and 8 days of the treatment. Then pathological evaluation was conducted. Finally, qRT-PCR was performed to determine angiogenesis.

RESULTS

The intervention groups had faster wound healing and lower wound area than the control group (p<0.05). The highest wound healing rate and the smallest wound area were observed in the group after receiving platelet cryogel plus MSCs. Angiogenesis, fibrosis, myoepithelial and epithelialization in the pathologic examination using H & E staining were not significantly different between the groups. The expression of Ang-1 in the intervention groups was higher than the control group and the highest expression was observed in the platelet cryogel plus MSCs, followed by the platelet cryogel group. The expression of VEGF in the plasma plus MSCs was higher than in the other groups.

CONCLUSION

Further studies require to determine the effects of combined use of platelet cryogel plus MSCs on other types of wounds and evaluate mechanisms involved in wound healing like collagenases and inflammatory factors.

Overview of current adipose-derived stem cell (ADSCs) processing involved in therapeutic advancements: flow chart and regulation updates before and after COVID-19

Adipose-derived stem cells (ADSCs) have raised big interest in therapeutic applications in regenerative medicine and appear to fulfill the criteria for a successful cell therapy. Their low immunogenicity and their ability to self-renew, to differentiate into different tissue-specific progenitors, to migrate into damaged sites, and to act through autocrine and paracrine pathways have been altogether testified as the main mechanisms whereby cell repair and regeneration occur. The absence of standardization protocols in cell management within laboratories or facilities added to the new technologies improved at patient's bedside and the discrepancies in cell outcomes and engraftment increase the limitations on their widespread use by balancing their real benefit versus the patient safety and security. Also, comparisons across pooled patients are particularly difficult in the fact that multiple medical devices are used and there is absence of harmonized assessment assays despite meeting regulations agencies and efficient GMP protocols. Moreover, the emergence of the COVID-19 breakdown added to the complexity of implementing standardization. Cell- and tissue-based therapies are completely dependent on the biological manifestations and parameters associated to and induced by this virus where the scope is still unknown. The initial flow chart identified for stem cell therapies should be reformulated and updated to overcome patient infection and avoid significant variability, thus enabling more patient safety and therapeutic efficiency. The aim of this work is to highlight the major guidelines and differences in ADSC processing meeting the current good manufacturing practices (cGMP) and the cellular therapy-related policies. Specific insights on standardization of ADSCs proceeding at different check points are also presented as a setup for the cord blood and bone marrow.

Combined use of platelet-rich plasma and adipose tissue-derived mesenchymal stem cells shows a synergistic effect in experimental spinal cord injury

Spinal cord injury (SCI) as a crippling disability causes tissue degeneration via neuron loss and fiber disruption. Some researchers have tried to reverse or minimize these changes. Platelet-rich plasma (PRP) is a biological product derived from peripheral blood containing a variety of growth factors. PRP has been extensively used in regenerative medicine. On the other hand, via secreting neuroprotective growth factors, mesenchymal stem cells (MSCs) have shown a promising potential in repairing central nervous system deficits. This study investigated the therapeutic effect of the combined use of MSCs and PRP in a rat model of SCI. We used real time-PCR method for evaluation of Bcl-2, Bax and caspase 3 expressions, TUNEL test for apoptotic cell death assessment, and neurofilament NF200 immunohistochemistry for examination of axonal regeneration. The results showed that co-treatment with MSCs and PRP efficiently alleviated the evaluated categories. Significant differences were observed in expression of Bcl-2 and caspase3, but not Bax, apoptotic index and the number of NF200 positive axons (for all P ≤ 0.01) between co-treatment animals compared with those treated with only MSCs or PRP. In conclusion, this study showed that combination of MSCs and PRP synergistically promotes their therapeutic effects in the SCI.

Evaluation of the Effect of Plasma from Patients with Trophic Ulcers on the Function of Dermal Fibroblasts, Mesenchymal Stem Cells, and Endothelial Cells

We studied the effect of platelet lysate and platelet-poor plasma from patients with trophic ulcers with and without type 2 diabetes mellitus on proliferation, migration, and apoptosis of human dermal fibroblast, mesenchymal stem cells, and endothelial cells. It is shown that plasma obtained from patients with type 2 diabetes mellitus produced inhibitory effects.

Use of platelet-rich plasma and modified nanofat grafting in infected ulcers: Technical refinements to improve regenerative and antimicrobial potential

Background

Surgical reconstruction of chronic wounds is often infeasible due to infection, comorbidities, or poor viability of local tissues. The aim of this study was to describe the authors’ technique for improving the regenerative and antimicrobial potential of a combination of modified nanofat and platelet-rich plasma (PRP) in nonhealing infected wounds.

Methods

Fourteen patients met the inclusion criteria. Fat tissue was harvested from the lower abdomen following infiltration of a solution of 1,000 mL of NaCl solution, 225 mg of ropivacaine, and 1 mg of epinephrine. Aspiration was performed using a 3-mm cannula with 1-mm holes. The obtained solution was decanted and mechanically emulsified, but was not filtered. Non-activated leukocyte-rich PRP (naLR-PRP) was added to the solution before injection. Patients underwent three sessions of injection of 8-mL naLR-PRP performed at 2-week intervals.

Results

Thirteen of 14 patients completed the follow-up. Complete healing was achieved in seven patients (53.8%). Four patients (30.8%) showed improvement, with a mean ulcer width reduction of 57.5%±13.8%. Clinical improvements in perilesional skin quality were reported in all patients, with reduced erythema, increased thickness, and increased pliability. An overall wound depth reduction of 76.6%±40.8% was found. Pain was fully alleviated in all patients who underwent re-epithelization. A mean pain reduction of 42%±33.3% (as indicated by visual analog scale score) was found in non-re-epithelized patients at a 3-month follow-up.

Conclusions

The discussed technique facilitated improvement of both the regenerative and the antimicrobial potential of fat grafting. It proved effective in surgically-untreatable infected chronic wounds unresponsive to conventional therapies.

Effects of Platelet-Rich Plasma on Proliferation, Viability, and Odontogenic Differentiation of Neural Crest Stem-Like Cells Derived from Human Dental Apical Papilla

Objective

This study is aimed at evaluating the effects of platelet-rich plasma (PRP) on proliferation, viability, and odontogenic differentiation of neural crest stem-like cells (NCSCs) derived from human dental apical papilla.

Materials and Methods

Cells from apical papillae were obtained and then induced to form neural spheres. The expression of NCSC markers p75NTR and HNK-1 in neural sphere cells was detected by immunofluorescence staining. Human PRP was prepared by a 2-step centrifugation method and activated by CaCl₂ and thrombin. The concentrations of PDGF-BB and TGF-β1 in whole blood and PRP were measured by an ELISA kit. PRP in five different concentrations (0%, 2.5%, 5%, 10%, and 25%) was applied to culture NCSCs. On the 1^st, 3^rd, 5^th, and 7^th days, cell proliferation was evaluated by CCK8. Cell viability was tested by a live/dead staining kit. mRNA and protein expression of DSPP and BMP4 were analyzed by RT-qPCR and western blot, respectively. Statistical analysis was performed by a one-way analysis of variance (ANOVA) test or t-test.

Results

Dental apical papilla cells formed neural spheres, from which cells displayed positive expression of p75NTR and HNK-1. The concentrations of PDGF-BB and TGF-β1 in PRP were about 3.5-fold higher than those in whole blood. 5% and 10% PRP significantly promoted proliferation of NCSCs, while 25% and 50% PRP inhibited cell proliferation from Day 3 to Day 7. Low-concentration (2.5%, 5%, and 10%) PRP slightly improved viability of NCSCs on Day 7. On the other hand, high-concentration (25% and 50%) PRP significantly inhibited viability of NCSCs from Day 3 to Day 7. RT-qPCR and western blot results indicated that 10% PRP could promote odontogenic differentiation of NCSCs on Day 7. mRNA and protein expression of DSPP and BMP4 were significantly upregulated in the 10% PRP group compared to those in the control group (P < 0.05).

Conclusions

PRP is a simply acquirable blood derivative which contains high concentration of growth factors like PDGF-BB and TGF-β1. PRP in a proper concentration could promote proliferation, viability, and odontogenic differentiation of NCSCs derived from human dental apical papilla.

Platelet-rich plasma counteracts detrimental effect of high-glucose concentrations on mesenchymal stem cells from Bichat fat pad

Diabetic patients display increased risk of periodontitis and failure in bone augmentation procedures. Mesenchymal stem cells (MSCs) and platelet-rich plasma (PRP) represent a relevant advantage in tissue repair process and regenerative medicine. We isolated MSCs from Bichat's buccal fat pad (BFP) and measured the effects of glucose and PRP on cell number and osteogenic differentiation potential. Cells were cultured in the presence of 5.5-mM glucose (low glucose [LG]) or 25-mM glucose (high glucose [HG]). BFP-MSC number was significantly lower when cells were cultured in HG compared with those in LG. Following osteogenic differentiation procedures, calcium accumulation, alkaline phosphatase activity, and expression of osteogenic markers were significantly lower in HG compared with LG. Exposure of BFP-MSC to PRP significantly increased cell number and osteogenic differentiation potential, reaching comparable levels in LG and in HG. Thus, high-glucose concentrations impair BFP-MSC growth and osteogenic differentiation. However, these detrimental effects are largely counteracted by PRP.

Activation of BK Channel Contributes to PL-Induced Mesenchymal Stem Cell Migration

Due to their capacity to proliferate, migrate, and differentiate, mesenchymal stem cells (MSCs) are considered to be good candidates for regenerative medicine applications. The mechanisms underlying proliferation and differentiation of MSCs have been studied. However, much less is known about the mechanisms regulating the migration of MSCs. Platelet lysate (PL), a supplement used to promote cell expansion, has been shown to promote MSCs migration; however, the underlying mechanism are unknown. Here, by using adipose-derived rat MSCs (rMSCs) and the scratch assay in the absence and presence of various BK channels modulators, we evaluated the role of BK channels in mediating the PL-stimulated migration of rMSCs. We found that 5% PL increased rMSCs migration, and this effect was blocked by the addition of the BK channel selective antagonist Iberiotoxin (IBTX). In the absence of PL, the BK channel agonist NS1619, stimulated rMSCs migration to similar level as 5% PL. Addition of both NS1619 and 5% PL resulted in an increase in rMSCs migration, that was higher than when either one was added individually. From whole-cell recordings, it was found that the addition of 5% PL increased the magnitude of BK current density. By using Western blot and flow cytometry, it was found that PL did not affect the expression of BK channels. Together, our results indicate that as shown in other cell types, activation of BK channels by themselves also promote rMSC migration, and show that activation of BK channels contribute to the observed PL-induced increase in migration of rMSC.

Plasma rich in growth factor gel as an autologous filler for facial volume restoration

BACKGROUND

Skin aging is characterized by moderate to severe wrinkles, laxity, roughness, and volume loss as a result of cutaneous atrophy and connective tissue degradation. Plasma rich in growth factor gel (PRGF-gel) is a novel formulation obtained from the patient's own blood that has demonstrated optimal biomechanical and bioactive properties for soft tissue restoration.

OBJECTIVES

Following a retrospective design, the clinical safety and efficacy of PRGF-gel for facial volume restoration and skin rejuvenation were evaluated.

METHODS

Twenty women clinically diagnosed for aged skin symptoms were treated with PRGF-gel. Participants received an individualized regimen depending on their therapeutic needs. At the end of the follow-up periods, clinical performance analysis was evaluated by standardized macrophotographs along with clinical and patient surveys based on Likert's scales.

RESULTS

Based on their initial expectations, patients referred to be highly satisfied after PRGF-gel treatment in terms of fine line amelioration, wrinkle reduction, and sagging improvement (overall satisfaction of 8/10). Pre/post-photograph clinical evaluation showed an improvement of 2.5/3 and patients presented a noticeable face rejuvenation due to the soft tissue augmentation effect which was translated into surface texture softening and tone recovery.

CONCLUSIONS

Although additional randomized clinical trials should be carried out, this study provides preliminary data supporting the use of PRGF-gel for facial volume restoration.

The Role of Platelet Concentrates in Facial Fat Grafting

Autologous fat grafting is increasingly being used as a method for the repair of facial soft tissue defects and facial rejuvenation, given its low risk of adverse effects and high efficacy. However, the unpredictability of graft retention is a limitation of this procedure. In addition, there is no standard procedure to date for autologous fat grafting. Different methods have been developed to increase the retention of grafted fat. For instance, platelet concentrates have been used to directly deliver bioactive factors to grafted fat. Platelet concentrates also provide incidental therapeutic benefits by enhancing the persistence of fat grafted in the face via the release of growth factors and cytokines. In this review, we describe current strategies for improving the survival of facial fat grafts, mainly focusing on the application of growth factors/cytokines and platelet concentrates to fat grafting.

Platelet-Rich Plasma Improves the Wound Healing Potential of Mesenchymal Stem Cells through Paracrine and Metabolism Alterations

Chronic and acute nonhealing wounds represent a major public health problem, and replacement of cutaneous lesions by the newly regenerated skin is challenging. Mesenchymal stem cells (MSC) and platelet-rich plasma (PRP) were separately tested in the attempt to regenerate the lost skin. However, these treatments often remained inefficient to achieve complete wound healing. Additional studies suggested that PRP could be used in combination with MSC to improve the cell therapy efficacy for tissue repair. However, systematic studies related to the effects of PRP on MSC properties and their ability to rebuild skin barrier are lacking. We evaluated in a mouse exhibiting 4 full-thickness wounds, the skin repair ability of a treatment combining human adipose-derived MSC and human PRP by comparison to treatment with saline solution, PRP alone, or MSC alone. Wound healing in these animals was measured at day 3, day 7, and day 10. In addition, we examined in vitro and in vivo whether PRP alters in MSC their proangiogenic properties, their survival, and their proliferation. We showed that PRP improved the efficacy of engrafted MSC to replace lost skin in mice by accelerating the wound healing processes and ameliorating the elasticity of the newly regenerated skin. In addition, we found that PRP treatment stimulated in vitro, in a dose-dependent manner, the proangiogenic potential of MSC through enhanced secretion of soluble factors like VEGF and SDF-1. Moreover, PRP treatment ameliorated the survival and activated the proliferation of in vitro cultured MSC and that these effects were accompanied by an alteration of the MSC energetic metabolism including oxygen consumption rate and mitochondrial ATP production. Similar observations were found in vivo following combined administration of PRP and MSC into mouse wounds. In conclusion, our study strengthens that the use of PRP in combination with MSC might be a safe alternative to aid wound healing.

Plasma-Alginate Composite Material Provides Improved Mechanical Support for Stem Cell Growth and Delivery

Blood plasma-based products have been recently utilized in different tissue engineering applications, ranging from soft tissue repair to bone regeneration. Plasma contains fibrinogen which can be converted to an insoluble fibrin-laden gel in the presence of activated thrombin. In tissue engineering, these plasma-based materials can serve either as a three-dimensional scaffold to deliver therapeutic cells in vivo or as a growth factor-rich supply for tissue regeneration. Unfortunately, plasma-based materials are often mechanically weak and easily deformed, thus limiting their usability in harsh clinical settings. Simpler methods to create sturdier plasma-based materials are therefore needed. To this end, we hypothesized that combining alginate with plasma can create a composite plasma material with improved mechanical properties. Incorporating alginate into plasma produced composite gels with increasing bulk stiffness, as measured by rheology. Specifically, the plasma-alginate composite (PAC) gels with an alginate concentration of 2.86 mg/mL were 10-fold stiffer than pure plasma gels (11 vs 112 Pa). Interestingly, gel lysis rates were unchanged despite increasing alginate concentration (lysis time approximately 50 min). Adipose-derived stem cells cultured in the stiffer PAC gels expressed stemness markers (THY1, ENG, NT5E) at levels comparable to those in the pure plasma gels. Similarly, proangiogenic factor secretion was also constant across all gel conditions. In sum, we envision this PAC gel system will extend the use of plasma gel-based therapies into more rigorous clinical applications.

A Preliminary Clinical Trial Comparing Split Treatments to the Face and Hand With Autologous Fat Grafting and Platelet-Rich Plasma (PRP): A 3D, IRB-Approved Study

BACKGROUND

Numerous methodologies have been suggested to enhance fat graft survival, but few long-term studies are available.

OBJECTIVES

The authors of this institutional review board-approved study investigated the safety and efficacy of utilizing platelet-rich plasma (PRP).

METHODS

Each of 10 patients received equal volumes of syringe-harvested, centrifuged fat to opposing midfaces with a lateral submuscular aponeurotic system-plication or no face lift and hands that were combined with equal volumes of either concentrated PRP or normal saline. Comparable assessments of fat retention/baseline values by 3D Vectra Analysis, VISIA, and Cortex facial skin analyses were performed. Clinical results were judged on a visual analogue scale.

RESULTS

The average percent change in mean volume assessments at the fat/PRP sites from baseline values, as profiled by 3D Vectra Analysis, demonstrated a higher, but statistically nonsignificant value over 1 year than the percent value changes at the fat/normal saline sites in the opposing face or hand. Three independent evaluators were able to assess volume restorations to the malar fat pad, naso-jugal groove, and nasolabial fold as well as to intermetacarpal hollowness with reduction of visible veins and tendons in the anterior midface and hands with both treatments. No adverse events were observed over the year-long study. Perioperative edema, erythema, bruising, and tenderness lasted up to 1 to 2 weeks at most.

CONCLUSIONS

Autologous fat grafting continues to be a safe and effective adjunct in facial and hand aesthetic surgery. This study will require more patients and longer follow-up periods to determine whether PRP has a potential role to increase fat graft retention in aesthetic patients.

LEVEL OF EVIDENCE: 3

Chondrogenic effect of liquid and gelled platelet lysate on canine adipose-derived mesenchymal stromal cells

Osteoarthritis associated with hip dysplasia is one of the most common orthopedic abnormalities in dogs, with an incidence of up to 40% in some breeds. Tissue therapy of cartilage has received great attention, with use of mesenchymal stromal cells and different types of biomaterials. The present study aimed to evaluate the effect of platelet lysate (PL) on the proliferation and differentiation of canine adipose tissue-derived mesenchymal stromal cells (ASCs), in liquid culture or hydrogels. PL was prepared from blood collected from healthy dogs and submitted to freezing-thawing cycles, and hydrogel was formed with canine thrombin. The effect of PL on the proliferation and differentiation of canine ASCs was evaluated in liquid and hydrogel systems, with microscopy, quantification of dsDNA, histology and quantification of glycosaminoglycans. The addition of 5% or 10% PL to the culture medium induced a greater proliferation rate than the presence of 10% fetal bovine serum. The cultivation of ASCs in PL gel, with normal or chondrogenic medium, resulted in maintenance of proliferation level similar to the conventional 2D cultivation, and induction of chondrogenic differentiation, especially in the presence of the chondrogenesis induction medium.

Encapsulation of bone marrow-MSCs in PRP-derived fibrin microbeads and preliminary evaluation in a volumetric muscle loss injury rat model: modular muscle tissue engineering

Repair of volumetric muscle loss (VML) injuries is a complicated endeavour which necessitates the collaborative use of different regenerative approaches and technologies. Herein is proposed the development of fibrin-based microbeads (FMs) alone or as a bone marrow mesenchymal stem cell (MSC) encapsulation matrix for modular muscle engineering. FMs were generated through the ionotropic gelation of alginate and fibrinogen obtained from the platelet-rich plasma of whole blood, and then removing the alginate by citrate treatment. FMs were first characterized by FT-IR, SEM and water uptake tests. Then, the stability of FMs and the mitochondrial dehydrogenase activity of the MSCs encapsulated in FMs were evaluated under in vitro culture conditions. Eventually, the regenerative capacity of the cell-devoid and MSCs-encapsulated FMs was evaluated in a rat VML injury model involving 8 × 4×4 mm³-size bilateral defects in the biceps femoris muscles. The histochemical, immunohistochemical and semi-quantitative histomorphological scoring results retrieved at 30, 60 and 180 days demonstrated that the cell-devoid FMs supported muscle regeneration to a great extent. Moreover, MSCs-encapsulated FMs were more effective in shortening the regeneration period of the injured tissue of the rat VML, resulting in good myofibre orientation, while the Sham group resulted in incomplete repair with fibrotic scar tissue formations.

The use of fat grafting and platelet-rich plasma for wound healing: A review of the current evidence

Fat grafting is becoming a common procedure in regenerative medicine because of its high content of growth factors and adipose derived stem cells (ADSCs) and the ease of harvest, safety, and low cost. The high concentration of ADSCs found in fat has the potential to differentiate into a wide range of wound-healing cells including fibroblasts and keratinocytes as well as demonstrating proangiogenic qualities. This suggests that fat could play an important role in wound healing. However retention rates of fat grafts are highly variable due in part to inconsistent vascularisation of the transplanted fat. Furthermore, conditions such as diabetes, which have a high prevalence of chronic wounds, reduce the potency and regenerative potential of ADSCs. Platelet-rich plasma (PRP) is an autologous blood product rich in growth factors, cell adhesion molecules, and cytokines. It has been hypothesised that PRP may have a positive effect on the survival and retention of fat grafts because of improved proliferation and differentiations of ADSCs, reduced inflammation, and improved vascularisation. There is also increasing interest in a possible synergistic effect that PRP may have on the healing potential of fat, although the evidence for this is very limited. In this review, we evaluate the evidence in both in vitro and animal studies on the mechanistic relationship between fat and PRP and how this translates to a benefit in wound healing. We also discuss future directions for both research and clinical practice on how to enhance the regenerative potential of the combination of PRP and fat.

Optimization of the Platelet-Rich Plasma Concentration for Mesenchymal Stem Cell Applications

IMPACT STATEMENT

In the current study, we screened the effects of different concentrations of platelet-rich plasma (PRP) on the mesenchymal stem cell (MSC) proliferation and differentiation. Our data demonstrated that concentrated PRP exerted different effects on cell proliferation and on the osteogenic, adipogenic, and chondrogenic differentiation of human bone marrow-derived MSCs. Meanwhile, we optimized PRP concentrations for each of these lineage differentiation and MSC expansion and, thus, suggested several promising clinical strategies for different kinds of diseases. These findings may help explain the controversial effects of PRP on MSCs and improve the progress in precise applications of PRP-based regenerative strategies.

Platelet-Rich Plasma, Adipose Tissue, and Scar Modulation

Level of Evidence: 4.

Platelet-rich Plasma and Mesenchymal Stem Cells: Exciting, But … are we there Yet?

Joint conditions incapacitate free movement driving to a sedentary lifestyle, a major risk factor for chronic diseases. Regenerative procedures, involving the use of mesenchymal stem/stromal cells along with platelet-rich plasma (PRP), can help patients with these conditions. We describe the main characteristics of cellular products (bone marrow concentrate, stromal vascular fraction of adipose tissue, and mesenchymal stem/stromal cells derived from these tissues), and the potential benefits of combination with PRP in 3 scenarios: PRP lysates used during laboratory cell expansion; PRP to prime cellular products or the host tissue before cell implantation; PRP used as a vehicle for cell transplantation and to provide trophic signals. Clinical studies exploring the benefits of combination products are limited to case series and few controlled studies, involving either arthroscopy or percutaneous injections. Combination products are making their way to clinics but further experimental and clinical research is needed to establish protocols and indications.

The Effect of Hexanoyl Glycol Chitosan on the Proliferation of Human Mesenchymal Stem Cells

Adipose-derived mesenchymal stem cells (AD-MSCs) have been studied as desirable cell sources for regenerative medicine and therapeutic application. However, it has still remained a challenge to obtain enough adequate and healthy cells in large quantities. To overcome this limitation, various biomaterials have been used to promote expansion of MSCs in vitro. Recently, hexanoyl glycol chitosan (HGC) was introduced as a new biomaterial for various biomedical applications, in particular 3D cell culture, because of its biodegradability, biocompatibility, and other promising biofunctional properties. In this study, the effect of HGC on the proliferation of AD-MSCs was examined in vitro, and its synergistic effect with basic fibroblast growth factor (bFGF), which has been widely used to promote proliferation of cells, was evaluated. We found that the presence of HGC increased the proliferative capacity of AD-MSCs during long-term culture, even at low concentrations of bFGF. Furthermore, it suppressed the expression of senescence-related genes and improved the mitochondrial functionality. Taken all together, these findings suggest that the HGC demonstrate a potential for sustained growth of AD-MSCs in vitro.

Biological Therapies in Regenerative Sports Medicine

Regenerative medicine seeks to harness the potential of cell biology for tissue replacement therapies, which will restore lost tissue functionality. Controlling and enhancing tissue healing is not just a matter of cells, but also of molecules and mechanical forces. We first describe the main biological technologies to boost musculoskeletal healing, including bone marrow and subcutaneous fat-derived regenerative products, as well as platelet-rich plasma and conditioned media. We provide some information describing possible mechanisms of action. We performed a literature search up to January 2016 searching for clinical outcomes following the use of cell therapies for sports conditions, tendons, and joints. The safety and efficacy of cell therapies for tendon conditions was examined in nine studies involving undifferentiated and differentiated (skin fibroblasts, tenocytes) cells. A total of 54 studies investigated the effects of mesenchymal stem-cell (MSC) products for joint conditions including anterior cruciate ligament, meniscus, and chondral lesions as well as osteoarthritis. In 22 studies, cellular products were injected intra-articularly, whereas in 32 studies MSC products were implanted during surgical/arthroscopic procedures. The heterogeneity of clinical conditions, cellular products, and approaches for delivery/implantation make comparability difficult. MSC products appear safe in the short- and mid-term, but studies with a long follow-up are scarce. Although the current number of randomized clinical studies is low, stem-cell products may have therapeutic potential. However, these regenerative technologies still need to be optimized.

The effect of mesenchymal stem cells combined with platelet-rich plasma on skin wound healing

INTRODUCTION

Mesenchymal stem cells (MSCs) are multipotent stem cells that have the potential of proliferation, high self-renewal, and the potential of multilineage differentiation. The differentiation potential of the MSCs in vivo and in vitro has caused these cells to be regarded as potentially appropriate tools for wound healing. After the burn, trauma or removal of the tumor of wide wounds is developed. Although standard treatment for skin wounds is primary healing or skin grafting, they are not always practical mainly because of limited autologous skin grafting.

EVIDENCE ACQUISITIONS

Directory of Open Access Journals (DOAJ), Google Scholar, PubMed (NLM), LISTA (EBSCO), and Web of Science have been searched.

EVIDENCE SYNTHESIS

For clinical use of the MSCs in wound healing, two key issues should be taken into account: First, engineering biocompatible scaffolds clinical use of which leads to the least amount of side effects without any immunologic response and secondly, use of stem cells secretions with the least amount of clinical complications despite their high capability of healing damage.

CONCLUSION

In light of the MSCs' high capability of proliferation and multilineage differentiation as well as their significant role in modulating immunity, these cells can be used in combination with tissue engineering techniques. Moreover, the MSCs' secretions can be used in cell therapy to heal many types of wounds. The combination of MSCs and PRP aids wound healing which could potentially be used to promote wound healing.

The Effects of Hyperacute Serum on Adipogenesis and Cell Proliferation of Mesenchymal Stromal Cells

Fat tissue, due to its high concentration of stem cells, has a role in aesthetic medicine and reconstructive surgery. However, poor survival of the transplanted cells still limits the usefulness of this material in regenerative medicine. Several studies indicated that platelet-rich plasma (PRP) may improve adipose tissue viability due to its growth factor content. This study aimed at investigating the effects of PRP and hyperacute serum (HAS) on the adipogenic lineage in vitro. PRP was prepared by using two centrifugation steps in the presence of anticoagulants, and HAS was isolated from activated platelet-rich fibrin within 10 min of blood drawing to prevent the propagation of inflammatory cascades. Metabolic activity and proliferation rate of human bone marrow-derived mesenchymal stem cells (hMSCs) cultivated in media supplemented with three types of serum additives (fetal calf serum [FCS], human PRP, or HAS) was determined by using a tetrazolium assay. Adipogenesis was evaluated in standard and pro-adipogenic media and tested by oil red staining, triglyceride content, and expression of specific genes. Adipogenic regulators in the sera were measured by multiplex ELISA assays. We observed that proliferation of hMSCs was supported by both FCS and HAS in a time-dependent manner, but surprisingly, PRP had a much weaker effect (change in proliferation rate after 5 days relative to metabolic activity on day 0-FCS: 5.4-fold change, HAS: 5.8-fold change, serum free 1.9-fold change, PRP: 3.0-fold change, p < 0.05). Lipogenesis was only observed in groups with adipogenic differentiation medium, with HAS showing a significantly stronger effect than PRP. This was confirmed by intensive accumulation of lysochrome dye in lipid droplets, higher triglyceride concentration, and elevated expression of specific adipogenic genes. Measurement of lipogenic proteins in the sera revealed that both PRP and HAS are abundant in them; however, PRP also contains anti-adipogenic factors, which explains its weaker and less reliable effect. The results of this study suggest that HAS provides more robust support than PRP in hMSCs proliferation as well as lipogenic differentiation, indicating that it may be a better adjuvant in fat grafting procedures.

Different Immune Signature in Youths Experiencing Antipsychotic-Induced Weight Gain Compared to Untreated Obese Patients

OBJECTIVES

To assess cytokine and chemokine levels in youth experiencing antipsychotic-induced weight gain (AIWG) compared to obese patients, hypothesizing a different "immune signature" between the two kinds of obesity.

METHODS

We compared a group of youth experiencing AIWG (N 19, mean age 159 months, mean body mass index [BMI] z-score 1.81) and an age-, gender-, and BMI-matched group of untreated obese patients (N 19, mean age 147 months, mean BMI z-score 2) for a wide range of cytokines and chemokines by using a multiplex ELISA test.

RESULTS

Platelet-derived growth factor (PDGF), interleukin (IL)1-β, IL4, IL8, IL9, IL12, IL 17, eotaxin, FGF, GMCSF, IP10, MIP1b, and vascular-endothelial growth factor (VEGF) were significantly lower in the AIWG group, whereas IL13 and RANTES were significantly higher. Controlling for age, sex, and BMI, PDGF, IL4, IL8, IL13, IL17, eotaxin, fibroblast growth factor (FGF), granulocyte-macrophage colony-stimulating factor (GMCSF), IP10, MIP1b, and VEGF remain significantly different.

CONCLUSION

A clearly different pattern of cytokines distinguishes the two kinds of obesity, suggesting a different immune signature. Interestingly, most of the cytokines and chemokines bearing proinflammatory effects resulted decreased in the AIWG group, whereas IL-13, which holds an immune-modulatory effect, resulted increased.

White cell and platelet content affects the release of bioactive factors in different blood-derived scaffolds

Platelet-derived factors are biomaterials that might accelerate healing process in oral, maxillofacial, and several other applications. Release of specific factors by platelet concentrates is critical to achieving a successful outcome. Here, we have shown that platelet-rich fibrin (PRF) clots were beneficial sources of leukocytes, which may directly affect the release of chemokines and growth factors. When compared with the standard leukocyte-PRF (L-PRF), the experimental low-force modified procedure [defined as advanced-PRF (A-PRF)] entrapped the same content of viable leukocytes, released a similar amount of inflammatory cytokines, but secreted 3-, 1.6-, 3-, and 1.2-fold higher levels of Eotaxin, CCL5, platelet-derived growth factor (PDGF) and vascular endothelial growth factor (VEGF), respectively. A leukocyte-free scaffold, such as plasma rich in growth factors (PRGF), released only platelet-specific factors and, in particular, the F3 fraction, the richest in growth factors, secreted higher amount of CCL5 and PDGF compared to F1 and F2 fractions. In conclusion, different procedures and leukocyte content affect cytokine, chemokines, and growth factor release from platelet derivatives, which may be helpful in different clinical settings.

Platelet-rich plasma respectively reduces and promotes adipogenic and myofibroblastic differentiation of human adipose-derived stromal cells via the TGFβ signalling pathway

Autologous fat grafting is a gold standard therapy for soft tissue defects, but is hampered by unpredictable postoperative outcomes. Fat graft enrichment with adipose-derived stromal cell (ASCs) was recently reported to enhance graft survival. Platelet-rich plasma (PRP) has also emerged as a biologic scaffold that promotes fat graft viability. Combined ASC/PRP fat grafting enrichment is thus a promising new regenerative medicine approach. The effects of PRP on ASC proliferation are well documented, but the impact of PRP on ASC differentiation has yet to be investigated in depth to further elucidate the PRP clinical effects. Here we analyzed the human ASC fate upon PRP treatment. PRP was found to sharply reduce the potential of ASCs to undergo differentiation into adipocytes. Interestingly, the PRP anti-adipogenic effect was accompanied by the generation of myofibroblast-like cells. Among the various factors released from PRP, TGFβ pathway activators played a critical role in both the anti-adipogenic and pro-myofibroblastic PRP effects. Overall, these data suggest that PRP participates in maintaining a pool of ASCs and in the repair process by promoting ASC differentiation into myofibroblast-like cells. TGFβ may provide an important target pathway to improve PRP clinical outcomes.

Analysis of migration rate and chemotaxis of human adipose-derived mesenchymal stem cells in response to LPS and LTA in vitro

Mesenchymal stem cells (MSC) are able to stimulate the regeneration of injured tissue. Since bacterial infections are common complications in wound healing, bacterial pathogens and their components come into direct contact with MSC. The interaction with bacterial structures influences the proliferation, differentiation and migratory activity of the MSC, which might be of relevance during regeneration. Studies on MSC migration in response to bacterial components have shown different results depending on the cell type. Here, we analyzed the migration rate and chemotaxis of human adipose-derived MSC (adMSC) in response to the basic cell-wall components lipopolysaccharide (LPS) of Gram-negative bacteria and lipoteichoic acid (LTA) of Gram-positive bacteria in vitro. To this end, we used transwell and scratch assays, as well as a specific chemotaxis assay combined with live-cell imaging. We found no significant influence of LPS or LTA on the migration rate of adMSC in transwell or scratch assays. Furthermore, in the µ-slide chemotaxis assay, the stimulation with LPS did not exert any chemotactic effect on adMSC.

Platelet-Rich Blood Derivatives for Stem Cell-Based Tissue Engineering and Regeneration

Platelet rich blood derivatives have been widely used in different fields of medicine and stem cell based tissue engineering. They represent natural cocktails of autologous growth factor, which could provide an alternative for recombinant protein based approaches. Platelet rich blood derivatives, such as platelet rich plasma, have consistently shown to potentiate stem cell proliferation, migration, and differentiation. Here, we review the spectrum of platelet rich blood derivatives, discuss their current applications in tissue engineering and regenerative medicine, reflect on their effect on stem cells, and highlight current translational challenges.

Adipose tissue-derived mesenchymal stem cells and platelet-rich plasma: stem cell transplantation methods that enhance stemness

Because of their ease of isolation and relative abundance, adipose-derived mesenchymal stem cells (ASCs) are a particularly attractive autologous cell source for various therapeutic purposes. ASCs retain a high proliferation capacity in vitro and have the ability to undergo extensive differentiation into multiple cell lineages. Moreover, ASCs secrete a wide range of growth factors that can stimulate tissue regeneration. Therefore, the clinical use of ASCs is feasible. However, the potential of ASCs differs depending on the donor's medical condition, including diseases such as diabetes. Recent studies demonstrated that ASCs from diabetic donors exhibit reduced proliferative potential and a smaller proportion of stem cell marker-positive cells. Therefore, to ensure the success of regenerative medicine, tissue engineering methods must be improved by the incorporation of factors that increase the proliferation and differentiation of stem/progenitor cells when autologous cells are used. Platelet-rich plasma (PRP), which contains high levels of diverse growth factors that can stimulate stem cell proliferation and cell differentiation in the context of tissue regeneration, has recently been identified as a biological material that could be applied to tissue regeneration. Thus, co-transplantation of ASCs and PRP represents a promising novel approach for cell therapy in regenerative medicine. In this review, we describe the potential benefits of adding PRP to ASCs and preclinical and clinical studies of this approach in various medical fields. We also discuss the mechanisms of PRP action and future cell-based therapies using co-transplantation of ASCs and PRP.

A dose response analysis of a specific bone marrow concentrate treatment protocol for knee osteoarthritis

Background

Prior studies describing the treatment of symptomatic knee osteoarthritis with injections of bone marrow concentrate have provided encouraging results. The relationship between the cellular dose contained within the bone marrow concentrate and efficacy of the treatment, however, is unclear. In the present study we describe clinical outcomes for symptomatic knee osteoarthritis in relation to higher and lower cell concentrations contained within a bone marrow concentrate treatment protocol.

Methods

Data from an ongoing patient registry was culled to identify 373 patients that received bone marrow concentrate injections for the treatment of 424 osteoarthritic knee joints. The clinical scales for these patients were assessed at baseline and then tracked post-procedure at 1, 3, 6 and 12 months, and annually thereafter. Tracked outcomes included the numeric pain scale; a lower extremity functional questionnaire; an International Knee Documentation Committee scale; and a subjective improvement rating scale. Using pain and functional outcome measures, a receiver operating characteristic analysis was used to define an optimal clinical outcome threshold at which bone marrow nucleated cell count could be divided into either a lower or higher cell count group within a treatment protocol.

Results

The lower and higher cell count groups were defined using a threshold of 4 × 10⁸ cells. There were 224 and 185 knee joints treated in the lower (≤4 × 10⁸) and higher (>4 × 10⁸) cell count groups respectively. Most joints were diagnosed with early stage knee osteoarthritis. Both the lower and higher cell count groups demonstrated significant positive results with the treatment for all of the pain and functional metrics. The higher cell count group reported lower post treatment numeric pain scale values, in comparison with the lower cell count group (1.6 vs. 3.2; P < 0.001). No significant differences were detected for the other metrics, however.

Conclusions

Improved function and reduced pain was observed in patients treated with a bone marrow concentrate protocol regardless of cellular dose; however, patients receiving a higher concentration of cells reported a better pain outcome in comparison with the lower dose group. These preliminary findings suggest that cell dose may be an important factor governing clinical outcomes in autologous bone marrow concentrate treatment of knee osteoarthritis. Further studies using a larger patient population may help elucidate these findings.