Platelet Lysate Activates Human Subcutaneous Adipose Tissue Cells by Promoting Cell Proliferation and Their Paracrine Activity Toward Epidermal Keratinocytes

HUC-MSCs combined with platelet lysate treat diabetic chronic cutaneous ulcers in Bama miniature pig

Human umbilical cord mesenchymal stem cells (HUC-MSCs) and platelet lysate (PL) shows potential of wound healing. However, MSCs in combination with PL for wound healing is still lacking. In this study, we presented high glucose cultured wound related cells to mimic diabetic chronic ulcers (DCU) cells, wound healing indicators and the TGFβ/Smad signaling pathway were detected by PL cultured HUC-MSC supernatant (MSC-Sp) in vitro. In vivo study, diabetes was induced in pigs feeding a high-energy diet and multiple injections of streptozotocin (125 mg/kg). Chronic wounds were created on both sides of the backs of seven pigs by surgical creation and foreign body compression for eight weeks before treatment. The wounds were treated with saline control (N = 11), PL (N = 11), HUC- MSCs (N = 18, 6 × 106/mL/cm2), and PL + HUC-MSCs (N = 18, 6 × 106/mL/cm2) respectively. Tissue samples were collected to observe new collagen, neovascularization, wound healing factors, and the TGFβ/Smad signaling pathway. The resulting PL-cultured MSC-Sp promoted the proliferation of keratinocytes, fibroblasts, and vascular endothelial cells and inhibited the TGFβ1/TGFβ3 ratio, upregulated VEGF-α and PDGF-BB production by keratinocytes and fibroblasts, and downregulated the expression of CD86, IL-6, and TNF-α in RAW264.7 cells. PL + HUC-MSCs had the best wound healing rate in vivo, and promoted collagen formation, neovascularization, and inflammation, regulated the balance between IL-6/TGFβ1 and IL-6/Arg-1 and upregulated the expression of VEGF-α and TGFβ1. In summary, PL + HUC-MSCs had a better wound healing effect than HUC-MSCs or PL treatment alone by regulating the IL-6/Arg-1 and IL-6/TGFβ1 balance and upregulating TGFβ1, VEGF-α, Col1, and α-SMA.

Perilesional injections of human platelet lysate versus platelet poor plasma for the treatment of diabetic foot ulcers: A double-blinded prospective clinical trial

Diabetic foot ulcer (DFU) is a major cause of morbidity, non-traumatic lower limb amputation in diabetic patients and a high-cost burden on the healthcare system. New therapeutic products are increasingly tested. Platelet-rich plasma (PRP) and human platelet lysate (hPL) are reported to be useful. This trial was conducted to test whether the healing effect of hPL in chronic DFU was due to plasma or platelet lysates in a prospective double-blind design. Autologous PRP was obtained from citrated blood, lysed, and used as drug 1 (active product). The platelet-poor plasma (PPP) was used as a drug 2 (placebo). Ten patients were enrolled in arm 1 and 9 in arm 2. The drugs were injected perilesionally every 2 weeks for a total of sixinjections. Adverse events were recorded until Week 14. The DFUs were scored per the Texas and Wegner systems. No patient showed any major adverse events. Some reported local pain post-injection. Wound healing was achieved in the hPL group in 9/10 of patients at a mean of 35.1 days. In the PPP group, no patient had healed by Day 84. The difference was statistically significant at P < 0.00001. We conclude that autologous hPL is safe and highly effective in healing chronic DFU and is superior to autologous PPP.

Quality Control Optimization for Minimizing Security Risks Associated with Mesenchymal Stromal Cell-Based Product Development

Mesenchymal stromal cells (MSCs) have been considered a therapeutic strategy in regenerative medicine because of their regenerative and immunomodulatory properties. The translation of MSC-based products has some challenges, such as regulatory and scientific issues. Quality control should be standardized and optimized to guarantee the reproducibility, safety, and efficacy of MSC-based products to be administered to patients. The aim of this study was to develop MSC-based products for use in clinical practice. Quality control assays include cell characterization, cell viability, immunogenicity, and cell differentiation; safety tests such as procoagulant tissue factor (TF), microbiological, mycoplasma, endotoxin, genomic stability, and tumorigenicity tests; and potency tests. The results confirm that the cells express MSC markers; an average cell viability of 96.9%; a low expression of HLA-DR and costimulatory molecules; differentiation potential; a high expression of TF/CD142; an absence of pathogenic microorganisms; negative endotoxins; an absence of chromosomal abnormalities; an absence of genotoxicity and tumorigenicity; and T-lymphocyte proliferation inhibition potential. This study shows the relevance of standardizing the manufacturing process and quality controls to reduce variability due to the heterogeneity between donors. The results might also be useful for the implementation and optimization of new analytical techniques and automated methods to improve safety, which are the major concerns related to MSC-based therapy.

Study of the biological characteristics of human umbilical cord mesenchymal stem cells after long-time cryopreservation

Human umbilical cord mesenchymal stem cells (hUC-MSCs) have considerable potential in cell therapy. Cryopreservation represents the gold standard in cell storage, but its effect on hUC-MSCs is still not well understood. The aim of this study was to investigate the effect of one year of cryopreservation and thawing on the biological characteristics of hUC-MSCs from the same donors. Fresh hUC-MSCs were cryopreserved in commercial freezing medium (serum-free CellBanker 2) at passage 2. After one year of cryopreservation, the hUC-MSCs were thawed and subcultured to passage 4. The comparison was performed in terms of followings: cell count, viability, morphology, proliferation capacity, differentiation potential and chromosomal stability. The total cell count and viability of hUC-MSCs before and after one year of cryopreservation were 1 × 107 and 96.34% and 0.943 × 107 and 93.81%, respectively. Cryopreserved and fresh hUC-MSCs displayed a similar cell doubling times, expressed the markers CD73, CD90, CD105 and were negative for the markers CD34, CD45, and HLA-DR. Karyotypes were found to be normal after one year of cryopreservation. The trilineage differentiation properties were maintained after cryopreservation. However, when compared to freshly isolated hUC-MSCs from the same donor, cryopreserved hUC-MSCs exhibited decreased expression of osteogenesis- and chondrogenesis-related genes including Runx2, Sox9, and Col1a1, and increased expression of adipogenesis-related genes. These results demonstrated that cryopreservation did not affect cell morphology, surface marker expression, cell viability, proliferative capacity, or chromosomal stability. However, the osteogenic and chondrogenic differentiation capacities of cryopreserved hUC-MSCs were slightly reduced compared with those of fresh cells from the same donor.

Adipose-Derived Stem Cell Conditioned Medium and Wound Healing: A Systematic Review

Adipose-derived stem cells (ASCs) have been growing in popularity for their potential in wound healing and tissue engineering. Stem cell therapies are limited in application, with the need to maintain cell viability and function as well as safety concerns. It has been increasingly reported that the effects of ASCs are predominantly attributable to the paracrine effects of the secreted factors, which can be collected in conditioned medium (CM). The goal of this systematic review is to investigate the effects on wound healing of CM collected from ASC culture. Original articles relevant to ASC-CM and wound healing (in vitro: dermal fibroblast, epidermal keratinocytes and their equivalent cell lines; in vivo: full-thickness wound models) were included. The agreement level of selections between two investigators were calculated by the kappa scores. And the information concerning to the publications, CM preparation and its application and effects were extracted and reported in a systematic way and summarized in tables. In total, 121 publications were initially identified through a search of the PubMed/MEDLINE database with a specific search algorithm, and 36 articles were ultimately included after two screenings. Nineteen were in vitro studies that met the search criteria and 17 were in vivo studies with or without in vitro data. In summary, based on the included articles, treatment with ASC conditioned medium (ASC-CM), to a large extent, resulted in positive effects on wound healing in vitro and in vivo. Modulation of the culture conditions of ASCs producing the CM, including hypoxic conditions, alternative substrates, medium supplementation, as well as genetic modification of cells, favorably promoted the effects of ASC-CM. Finally, a discussion of the future perspectives and therapeutic potential of ASC-CM, which also addresses the limitations of the field, is presented. A limitation of the evidence is the inconsistency in CM preparation methods among included articles. In conclusion, ASC-CM is a promising novel cell-free therapy for wound healing in regenerative medicine and warrants further exploration.

Adipose-Derived Stromal/Stem Cell Culture: Effects of Different Concentrations of Human Platelet Lysate in Media

Adipose-derived stromal/stem cells (ASCs) are being tested as a possible treatment for a wide range of diseases to exploit the immunomodulatory and regenerative potential demonstrated in vitro. Pooled human platelet lysate (pHPL) has replaced fetal bovine serum (FBS) as the preferred growth supplement because of its xeno-free origin and improved cell proliferation. Much has been done toward reducing the concentration of pHPL required when expanding ASCs. However, little is known on how increasing the concentration of pHPL affects ASC potency, which could lead to changes with possible beneficial applications. This study investigated the effect of 5, 10, or 20% pHPL in culture media on ASC proliferation and phenotypic marker expression, including chemokine receptors CXCR2, CXCR3, CXCR4, and VLA-4. Adipogenic and osteogenic properties, as well as immunosuppressive properties, including the ability to induce indoleamine-pyrrole 2,3-dioxygenase 1 (IDO1) and suppress T cell proliferation, were also examined. We observed a significant increase in cell yield (approximately 2-fold) and a corresponding reduction in population doubling time and cell volume when doubling the concentration of pHPL in the growth media. ASCs maintained expression of phenotypic surface markers CD73, CD90, and CD105 and were negative for CD45 and CD31. The ability to induce IDO1 and suppress T cell proliferation was observed as well. Adipogenesis and osteogenesis, however, seem to be increased at higher concentrations of pHPL (20% > 10% > 5%), while expression of chemokine receptors CXCR2 and CXCR3 was lower. In conclusion, increasing the pHPL concentration to 20% could be used to optimize culture conditions when producing cells for clinical treatments and may even be used to enhance beneficial ASC properties depending on the desired therapeutic effect.

Influence of platelet storage time on human platelet lysates and platelet lysate-expanded mesenchymal stromal cells for bone tissue engineering

Background

Human platelet lysate (HPL) is emerging as the preferred xeno-free supplement for the expansion of mesenchymal stromal cells (MSCs) for bone tissue engineering (BTE) applications. Due to a growing demand, the need for standardization and scaling-up of HPL has been highlighted. However, the optimal storage time of the source material, i.e., outdated platelet concentrates (PCs), remains to be determined. The present study aimed to determine the optimal storage time of PCs in terms of the cytokine content and biological efficacy of HPL.

Methods

Donor-matched bone marrow (BMSCs) and adipose-derived MSCs (ASCs) expanded in HPL or fetal bovine serum (FBS) were characterized based on in vitro proliferation, immunophenotype, and multi-lineage differentiation. Osteogenic differentiation was assessed at early (gene expression), intermediate [alkaline phosphatase (ALP) activity], and terminal stages (mineralization). Using a multiplex immunoassay, the cytokine contents of HPLs produced from PCs stored for 1–9 months were screened and a preliminary threshold of 4 months was identified. Next, HPLs were produced from PCs stored for controlled durations of 0, 1, 2, 3, and 4 months, and their efficacy was compared in terms of cytokine content and BMSCs’ proliferation and osteogenic differentiation.

Results

BMSCs and ASCs in both HPL and FBS demonstrated a characteristic immunophenotype and multi-lineage differentiation; osteogenic differentiation of BMSCs and ASCs was significantly enhanced in HPL vs. FBS. Multiplex network analysis of HPL revealed several interacting growth factors, chemokines, and inflammatory cytokines. Notably, stem cell growth factor (SCGF) was detected in high concentrations. A majority of cytokines were elevated in HPLs produced from PCs stored for ≤ 4 months vs. > 4 months. However, no further differences in PC storage times between 0 and 4 months were identified in terms of HPLs’ cytokine content or their effects on the proliferation, ALP activity, and mineralization of BMSCs from multiple donors.

Conclusions

MSCs expanded in HPL demonstrate enhanced osteogenic differentiation, albeit with considerable donor variation. HPLs produced from outdated PCs stored for up to 4 months efficiently supported the proliferation and osteogenic differentiation of MSCs. These findings may facilitate the standardization and scaling-up of HPL from outdated PCs for BTE applications.

Platelet Lysate Induces in Human Osteoblasts Resumption of Cell Proliferation and Activation of Pathways Relevant for Revascularization and Regeneration of Damaged Bone

To understand the regenerative effect of platelet-released molecules in bone repair one should investigate the cascade of events involving the resident osteoblast population during the reconstructive process. Here the in vitro response of human osteoblasts to a platelet lysate (PL) stimulus is reported. Quiescent or very slow dividing osteoblasts showed a burst of proliferation after PL stimulation and returned to a none or very slow dividing condition when the PL was removed. PL stimulated osteoblasts maintained a differentiation capability in vitro and in vivo when tested in absence of PL. Since angiogenesis plays a crucial role in the bone healing process, we investigated in PL stimulated osteoblasts the activation of hypoxia-inducible factor 1-alpha (HIF-1α) and signal transducer and activator of transcription 3 (STAT3) pathways, involved in both angiogenesis and bone regeneration. We observed phosphorylation of STAT3 and a strong induction, nuclear translocation and DNA binding of HIF-1α. In agreement with the induction of HIF-1α an enhanced secretion of vascular endothelial growth factor (VEGF) occurred. The double effect of the PL on quiescent osteoblasts, i.e., resumption of proliferation and activation of pathways promoting both angiogenesis and bone formation, provides a rationale to the application of PL as therapeutic agent in post-traumatic bone repair.

Helium/Argon-Generated Cold Atmospheric Plasma Facilitates Cutaneous Wound Healing

Cold atmospheric plasma jet (CAPJ) or non-thermal plasma jet has been employed in various biomedical applications based on their functions in bactericidal activity and wound healing. However, the effect of CAPJ generated by a particular composition of gases on wound closure and the underlying mechanisms that regulate wound healing signals remain elusive. In the present study, we investigated the impact of helium (He)- or a gas mixture of He and argon (He/Ar)-generated CAPJ on cell proliferation, which is a pivotal step during the wound healing process. With careful treatment duration control, He/Ar-CAPJ effectively induced keratinocyte proliferation and migration mediated through the activation of epithelial-to-mesenchymal transition (EMT) and cell cycle progression, which was evidenced by a decrease in E-cadherin levels and increases in N-cadherin, cyclin D1, Ki-67, Cdk2, and p-ERK levels. Rat wound healing studies showed that He/Ar-CAPJ treatment facilitated granulation tissue formation and mitigated inflammation in cutaneous tissue, resulting in accelerated wound closure. These findings highlight the possibility that He/Ar-CAPJ can be developed as a therapeutic agent for enhancing wound healing.

Progenitor Cells Activated by Platelet Lysate in Human Articular Cartilage as a Tool for Future Cartilage Engineering and Reparative Strategies

Regenerative strategies for human articular cartilage are still challenging despite the presence of resident progenitor cell population. Today, many efforts in the field of regenerative medicine focus on the use of platelet derivatives due to their ability to reactivate endogenous mechanisms supporting tissue repair. While their use in orthopedics continues, mechanisms of action and efficacy need further characterization. We describe that the platelet lysate (PL) is able to activate chondro-progenitor cells in a terminally differentiated cartilage tissue. Primary cultures of human articular chondrocytes (ACs) and cartilage explants were set up from donor hip joint biopsies and were treated in vitro with PL. PL recruited a chondro-progenitors (CPCs)-enriched population from ex vivo cartilage culture, that showed high proliferation rate, clonogenicity and nestin expression. CPCs were positive for in vitro tri-lineage differentiation and formed hyaline cartilage-like tissue in vivo without hypertrophic fate. Moreover, the secretory profile of CPCs was analyzed, together with their migratory capabilities. Some CPC-features were also induced in PL-treated ACs compared to fetal bovine serum (FBS)-control ACs. PL treatment of human articular cartilage activates a stem cell niche responsive to injury. These facts can improve the PL therapeutic efficacy in cartilage applications.

A Comparative Analysis of Multipotent Mesenchymal Stromal Cells derived from Different Sources, with a Focus on Neuroregenerative Potential

Multipotent mesenchymal stromal cells (MSCs) can be considered an accessible therapeutic tool for regenerative medicine. Here, we compared the growth kinetics, immunophenotypic and immunomodulatory properties, gene expression and secretome profile of MSCs derived from human adult bone marrow (BM-MSCs), adipose tissue (AT-MSCs) and Wharton’s jelly (WJ-MSCs) cultured in clinically-relevant conditions, with the focus on the neuroregenerative potential. All the cell types were positive for CD10/CD29/CD44/CD73/CD90/CD105/HLA-ABC and negative for CD14/CD45/CD235a/CD271/HLA-DR/VEGFR2 markers, but they differed in the expression of CD34/CD133/CD146/SSEA-4/MSCA-1/CD271/HLA-DR markers. BM-MSCs displayed the highest immunomodulatory activity compared to AT- and WJ-MSCs. On the other hand, BM-MSCs secreted the lower content and had the lower gene expression of neurotrophic growth factors compared to other cell lines, which may be caused by the higher sensitivity of BM-MSCs to nutrient limitations. Despite the differences in growth factor secretion, the MSC secretome derived from all cell sources had a pronounced neurotrophic potential to stimulate the neurite outgrowth of DRG-neurons and reduce the cell death of neural stem/progenitor cells after H₂O₂ treatment. Overall, our study provides important information for the transfer of basic MSC research towards clinical-grade manufacturing and therapeutic applications.

Hopes and Limits of Adipose-Derived Stem Cells (ADSCs) and Mesenchymal Stem Cells (MSCs) in Wound Healing

Adipose tissue derived stem cells (ADSCs) are mesenchymal stem cells identified within subcutaneous tissue at the base of the hair follicle (dermal papilla cells), in the dermal sheets (dermal sheet cells), in interfollicular dermis, and in the hypodermis tissue. These cells are expected to play a major role in regulating skin regeneration and aging-associated morphologic disgraces and structural deficits. ADSCs are known to proliferate and differentiate into skin cells to repair damaged or dead cells, but also act by an autocrine and paracrine pathway to activate cell regeneration and the healing process. During wound healing, ADSCs have a great ability in migration to be recruited rapidly into wounded sites added to their differentiation towards dermal fibroblasts (DF), endothelial cells, and keratinocytes. Additionally, ADSCs and DFs are the major sources of the extracellular matrix (ECM) proteins involved in maintaining skin structure and function. Their interactions with skin cells are involved in regulating skin homeostasis and during healing. The evidence suggests that their secretomes ensure: (i) The change in macrophages inflammatory phenotype implicated in the inflammatory phase, (ii) the formation of new blood vessels, thus promoting angiogenesis by increasing endothelial cell differentiation and cell migration, and (iii) the formation of granulation tissues, skin cells, and ECM production, whereby proliferation and remodeling phases occur. These characteristics would be beneficial to therapeutic strategies in wound healing and skin aging and have driven more insights in many clinical investigations. Additionally, it was recently presented as the tool key in the new free-cell therapy in regenerative medicine. Nevertheless, ADSCs fulfill the general accepted criteria for cell-based therapies, but still need further investigations into their efficiency, taking into consideration the host-environment and patient-associated factors.

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.

Platelet Lysate Inhibits NF-κB Activation and Induces Proliferation and an Alert State in Quiescent Human Umbilical Vein Endothelial Cells Retaining Their Differentiation Capability

Injured blood vessel repair and blood circulation re-establishment are crucial events for tissue repair. We investigated in primary cultures of human umbilical vein endothelial cells (HUVEC), the effects of platelet lysate (PL), a cocktail of factors released by activated platelets following blood vessel disruption and involved in the wound-healing process triggering. PL exerted a protective effect on HUVEC in an inflammatory milieu by inhibiting IL-1α-activated NF-κB pathway and by inducing the secretion of PGE₂, a pro-resolving molecule in the wound microenvironment. Moreover, PL enhanced HUVEC proliferation, without affecting their capability of forming tube-like structures on matrigel, and activated resting quiescent cells to re-enter cell cycle. In agreement with these findings, proliferation-related pathways Akt and ERK_1/2 were activated. The expression of the cell-cycle activator Cyclin D1 was also enhanced, as well as the expression of the High Mobility Group Box-1 (HMGB1), a protein of the alarmin group involved in tissue homeostasis, repair, and remodeling. These in vitro data suggest a possible in vivo contribution of PL to new vessel formation after a wound by activation of cells resident in vessel walls. Our biochemical study provides a rationale for the clinical use of PL in the treatment of wound healing-related pathologies.