The Effect of Blood-Derived Products on the Chondrogenic and Osteogenic Differentiation Potential of Adipose-Derived Mesenchymal Stem Cells Originated from Three Different Locations

Phloridzin functionalized gelatin-based scaffold for bone tissue engineering

Polyphenol-functionalized biomaterials are significant in the field of bone tissue engineering (BTE) due to their antioxidant, anti-inflammatory, and osteoinductive properties. In this study, a gelatin (Gel)-based scaffold was functionalized with phloridzin (Ph), the primary polyphenol in apple by-products, to investigate its influence on physicochemical and morphological, properties of the scaffold for BTE application. A preliminary assessment of the biological properties of the functionalized scaffold was also undertaken. The Ph-functionalized scaffold (Gel/Ph) exhibited a porous structure with high porosity (71.3 ± 0.3 %), a pore size of 206.5 ± 1.7 μm, and a radical scavenging activity exceeding 70 %. This scaffold with Young's modulus of 10.8 MPa was determined to support cell proliferation and exhibited cytocompatibility with mesenchymal stem cells (MSCs). Incorporating hydroxyapatite nanoparticle (HA) in the Gel/Ph scaffold stimulated the osteogenic differentiation of key osteogenic genes, including Runx2, ALPL, COL1A1, and OSX ultimately promoting mineralization. This research highlights the promising potential of utilizing polyphenolic compounds derived from fruit waste to functionalize scaffolds for BTE applications.

[Blood Products and Stem Cells in Osteoarthritis Therapy]

The principle of regenerative medicine in the treatment of osteoarthritis pursues a functional restoration of cartilage tissue instead of just repairing cartilage defects. The use of blood products is intended to inhibit chronic inflammatory processes and promote tissue regeneration. Intraarticular injection of autologous platelet-rich plasma (PRP) is a prominent procedure. Clinical evidence supports PRP injection over hyaluronic acid or glucocorticoid injection. Comparability of studies is difficult due to missing standardisation of production procedures, dosing and donor variability. In particular, whether presence of residual leukocytes is required or should be avoided is an open debate. In contrast, stem cell therapies in osteoarthritis therapy are often based on mesenchymal stem cells (MSC) from adipose tissue or bone marrow aspirate. Different sources of MSC might render the cells more suitable for application in a given context. Nevertheless, it became evident that their secretome rather than the cells themselves are responsible for observed regenerative processes. Research on the mechanisms of action have focused on growth factors. However, an overlooked component of blood products called extracellular vesicles (EV) came to the center of attention, which are also released by MSC as intercellular signal carriers. EV cargo molecules such as miRNAs open up new dimensions in the investigation and explanation of clinically observed anti-inflammatory and regenerative effects.

Culture of Hoffa fat pad mesenchymal stem/stromal cells on microcarrier suspension in vertical wheel bioreactor for extracellular vesicle production

BACKGROUND

Mesenchymal stromal cells (MSCs) are increasingly employed in regenerative medicine approaches for their immunomodulatory and anti-inflammatory properties, which are encoded in their secretome including extracellular vesicles (EVs). The Hoffa fat pad (HFP) located infrapatellarly harbours MSCs that could assist in tissue homeostasis in osteoarthritic joints. Intraarticular injection therapies based on blood products could modulate the populations of released HFP-MSC-EVs in a quantitative manner.

METHODS

To obtain amounts of HFP-MSC-derived EVs that allow pre-clinical evaluation, suitable EV production systems need to be developed. This work investigates the release of EVs from primary HFP-MSCs cultivated in a 3D environment using microcarrier suspension culture in a vertical wheel bioreactor in comparison to conventional 2D culture. To simulate an intraarticular blood product therapy, cultures were treated with citrate-anticoagulated platelet-rich plasma (CPRP) or hyperacute serum (hypACT) before EV collection. HFP-MSC-EVs are enriched via ultrafiltration and characterised via Western Blot, nanoparticle tracking analysis in scatter as well as fluorescence mode. EV potency was determined via RT-qPCR analysing the expression of type II and X collagen (COL2 and COL10), as well as inducible nitric oxide synthase (iNOS) in primary OA chondrocytes.

RESULTS

Blood product supplementation elevated HFP-MSC metabolic activity as determined via XTT assay over the course of 14 days. 3D culture resulted in a roughly 100-fold EV yield compared to 2D culture and elevated number of EVs released per cell. Total protein content correlated with the EV concentration. While typical EV marker proteins such as CD9, CD63 or Alix were detected in total protein extracts, CD9 and CD73 colocalised on individual EVs highlighting their cell origin. The type of blood product treatment did not affect the size or concentration of EVs obtained from HFP-MSCs. Assessing potency of 3D culture EVs in comparison to 2D EVs revealed superior biological activity with regard to inhibition of inflammation, inhibition of chondrocyte hypertrophy and induction of cartilage-specific ECM production.

CONCLUSIONS

HFP-MSCs proliferate in presence of human blood products indicating that animal serum in culture media can be avoided in the future. The culture of HFP-MSCs in the employed bioreactor was successfully used to generate quantities of EVs that could allow evaluation of HFP-MSC-EV-mediated effects in pre-clinical settings. In addition, EV potency of 3D EVs is superior to EVs obtained in conventional 2D culture flasks.

Effects of Blood-Derived Products on Cellular Senescence and Inflammatory Response: A Study on Skin Rejuvenation

Blood-derived products, such as citrate platelet-rich plasma (CPRP) and hyperacute serum (HAS), are recognized for their rich growth factor content. When human dermal fibroblast (HDF) cells are exposed to combined mitogenic and DNA-damaging stimuli, it can lead to an increased burden of senescent cells and a modified senescence-associated secretory phenotype. In this study, the senescent state was comprehensively assessed through various methods, including phosphorylated histone H2AX (γH2AX) staining, p21 and p16 q-PCR, p21-western blot, growth curves, and senescence-associated ß-galactosidase staining. Two primary treatments with blood products were administered, one early (immediately after etoposide) and the other late (11 days after etoposide treatment). The effects of the blood product treatment were evaluated by measuring interleukin 6 and 8 (IL-6 and IL-8) levels, as well as collagen 1 (COL1) and p21 mRNA expression. Additionally, 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT) assays, cell size measurements, viability assays, and cell number calculations were conducted. The results revealed that cells treated with hyperacute serum in the early treatment phase exhibited the lowest observed IL-6 and IL-8 levels. In contrast, a clear inflammatory response for IL-8 was observed in cells treated with hyperacute serum and citrate platelet-rich plasma during the late treatment. Furthermore, an upregulation of COL1 expression was observed in the early treatment, while cells in the late treatment group remained unaffected. Notably, citrate platelet-rich plasma-treated cells showed a decrease in COL1 expression. Overall, the treatment with blood products appears to have slightly positive effects on skin rejuvenation.

Hyperacute Serum and Knee Osteoarthritis

The knees are the most frequently affected weight-bearing joints in osteoarthritis (OA), impacting millions of people globally. With increasing life spans and obesity rates, the prevalence of knee OA will further mount, leading to a significant increase in the economic burden. The usual treatment modalities utilized to manage knee OA have shortcomings. Over the last decade, the field of regenerative medicine involving the use of biologics, such as autologous peripheral blood-derived orthobiologics, including hyperacute serum (HS), has evolved and shown potential for managing knee OA. In this manuscript, we qualitatively present the in vitro, pre-clinical, clinical, and ongoing studies investigating the applications of HS in the context of knee OA. Seven in vitro studies and one clinical study fit the scope of our manuscript. The results demonstrated that the administration of HS is potentially safe and efficacious in terms of increasing the viability of osteoarthritic chondrocytes, reducing pain and inflammation, and improving function in patients with knee OA. However, due to insufficient literature, pre-clinical studies to better understand the mechanism of action are required. In addition, adequately powered, multi-center, non-randomized, and randomized controlled trials with longer follow-up are warranted to establish the safety and efficacy of HS for the management of knee OA and to justify its clinical use.

Infra-patellar fat pad-derived mesenchymal stem cells maintain their chondrogenic differentiation potential after arthroscopic harvest with blood-product supplementation

PURPOSE

Mesenchymal stem cells/medicinal signaling cells (MSCs) possess therapeutic potential and are used in regenerative orthopaedics. The infra-patellar fat pad (IFP) is partially resected during knee arthroscopy (KASC) and contains MSCs. Heat, irrigation, and mechanical stress during KASC may decrease MSC's therapeutic potential. This study assessed MSCs' regenerative potential after arthroscopic IFP harvest and potential effects of two blood products (BP) (platelet-rich plasma (PRP), hyperacute serum (HAS)) on MSCs' viability and chondrogenic differentiation capacity.

METHODS

IFP was arthroscopically harvested, isolated, and counted (n = 5). Flow cytometry was used to assess cell viability via staining with annexin V/7-AAD and stemness markers via staining for CD90, CD73, and CD105. MSCs were incubated with blood products, and metabolic activity was determined via an XTT assay. Deposition of cartilage extracellular matrix was determined in histologic sections of chondrogenically differentiated 3D pellet cultures via staining with Alcian Blue. Expression of cartilage-specific genes (SOX9, MMP3/13, ACAN, COL1/2) was analyzed via quantitative PCR.

RESULTS

MSC isolation from IFP yielded 2.66*106 ± 1.49*106 viable cells from 2.7 (0.748) g of tissue. MSC markers (CD 90/105/73) were successfully detected and annexin V staining showed 81.5% viable cells. XTT showed increased metabolic activity. Within the BP groups, this increase was significant (days 0-14, p < 0.05). PCR showed expression of cartilage-specific genes in each group. COL2 (p < 0.01) as well as ACAN (p < 0.001) expression levels were significantly higher in the HAS group. Histology showed successful differentiation.

CONCLUSION

Arthroscopic harvest of IFP-MSCs yields sufficient cells with maintained regenerative potential and viability. Blood products further enhance MSCs' viability.

Isolation and Cultivation of Adipose-Derived Mesenchymal Stem Cells Originating from the Infrapatellar Fat Pad Differentiated with Blood Products: Method and Protocol

Adipose-derived mesenchymal stem cells (ASCs) are a promising source for clinical application in regenerative orthopedics. ASCs derived from the infra-patellar fat pad (IFP)-a distinct adipose structure in the knee-show superior regenerative potential compared to subcutaneous-fat-derived cells. Furthermore, it has been shown that blood products enhance ASCs' viability. A major challenge for clinical translation of both ASCs and blood products is the low comparability of obtained data due to non-standardized harvesting, isolation and preparation methods. The aim of this method-paper is to provide reproducible protocols to help standardize basic research in the field to build a sound basis for clinical translation with an emphasize on practicability. The presented protocols include (i) ASC isolation from the IFP, (ii) blood product preparation and (iii) ASC incubation with blood products.

Albumin as a Biomaterial and Therapeutic Agent in Regenerative Medicine

Albumin is a constitutional plasma protein, with well-known biological functions, e.g., a nutrient for stem cells in culture. However, albumin is underutilized as a biomaterial in regenerative medicine. This review summarizes the advanced therapeutic uses of albumin, focusing on novel compositions that take advantage of the excellent regenerative potential of this protein. Albumin coating can be used for enhancing the biocompatibility of various types of implants, such as bone grafts or sutures. Albumin is mainly known as an anti-attachment protein; however, using it on implantable surfaces is just the opposite: it enhances stem cell adhesion and proliferation. The anticoagulant, antimicrobial and anti-inflammatory properties of albumin allow fine-tuning of the biological reaction to implantable tissue-engineering constructs. Another potential use is combining albumin with natural or synthetic materials that results in novel composites suitable for cardiac, neural, hard and soft tissue engineering. Recent advances in materials have made it possible to electrospin the globular albumin protein, opening up new possibilities for albumin-based scaffolds for cell therapy. Several described technologies have already entered the clinical phase, making good use of the excellent biological, but also regulatory, manufacturing and clinical features of serum albumin.

Early Transfusion of Convalescent Plasma Improves the Clinical Outcome in Severe SARS-CoV2 Infection

INTRODUCTION

Plasma harvested from convalescent COVID-19 patients (CCP) has been applied as first-line therapy in the early phase of the SARS-CoV2 pandemic through clinical studies using various protocols.

METHODS

We present data from a cohort of 267 hospitalized severe COVID-19 patients who received CCP. No transfusion-related complications were reported, indicating the overall safety of CCP therapy.

RESULTS

Patients who eventually died from COVID-19 received CCP significantly later (3.95 versus 5.22 days after hospital admission) and had higher interleukin 6 (IL-6) levels (28.9 pg/ml versus 102.5 pg/ml) than those who survived. In addition, CCP transfusion caused a significant reduction in the overall inflammatory status of the patients regardless of the severity of disease or outcome, as evidenced by decreasing C-reactive protein, IL6 and ferritin levels.

CONCLUSION

We conclude that CCP transfusion is a safe and effective supplementary treatment modality for hospitalized COVID-19 patients characterized by better expected outcome if applied as early as possible. We also observed that IL-6 may be a suitable laboratory parameter for patient selection and monitoring of CCP therapy effectiveness.

Platelet-Rich Plasma Does Not Inhibit Inflammation or Promote Regeneration in Human Osteoarthritic Chondrocytes In Vitro Despite Increased Proliferation

OBJECTIVE

The aims of the study were to assess the anti-inflammatory properties of platelet-rich plasma (PRP) and investigate its regenerative potential in osteoarthritic (OA) human chondrocytes. We hypothesized that PRP can modulate the inflammatory response and stimulate cartilage regeneration.

DESIGN

Primary human chondrocytes from OA knees were treated with manually prepared PRP, after which cell migration and proliferation were assessed. Next, tumor necrosis factor-α-stimulated chondrocytes were treated with a range of concentrations of PRP. Expression of genes involved in inflammation and chondrogenesis was determined by real-time polymerase chain reaction. In addition, chondrocytes were cultured in PRP gels and fibrin gels consisting of increasing concentrations of PRP. The production of cartilage extracellular matrix (ECM) was assessed. Deposition and release of glycosaminoglycans (GAG) and collagen was quantitatively determined and visualized by (immuno)histochemistry. Proliferation was assessed by quantitative measurement of DNA.

RESULTS

Both migration and the inflammatory response were altered by PRP, while proliferation was stimulated. Expression of chondrogenic markers COL2A1 and ACAN was downregulated by PRP, independent of PRP concentration. Chondrocytes cultured in PRP gel for 28 days proliferated significantly more when compared with chondrocytes cultured in fibrin gels. This effect was dose dependent. Significantly less GAGs and collagen were produced by chondrocytes cultured in PRP gels when compared with fibrin gels. This was qualitatively confirmed by histology.

CONCLUSIONS

PRP stimulated chondrocyte proliferation, but not migration. Also, production of cartilage ECM was strongly downregulated by PRP. Furthermore, PRP did not act anti-inflammatory on chondrocytes in an in vitro inflammation model.

Optimization of Lyophilized Hyperacute Serum (HAS) as a Regenerative Therapeutic in Osteoarthritis

Hyperacute serum (HAS) is a blood derivative product that promotes the proliferation of various cell types and controls inflammation in vitro. The aim of this study is to investigate the regenerative potential of different formulations of HAS, including lyophilized and hyaluronic acid combined versions, to obtain a stable and standardized therapeutic in osteoarthritis (OA), which may be able to overcome the variability limitations of platelet-rich plasma (PRP). Primary human osteoarthritic chondrocytes were used for testing cellular viability and gene expression of OA-related genes. Moreover, a co-culture of human explants of cartilage, bone and synovium under inflammatory conditions was used for investigating the inflammatory control capacities of the different therapeutics. In this study, one formulation of lyophilized HAS achieved the high cell viability rates of liquid HAS and PRP. Gene expression analysis showed that HAS induced higher Col1a1 expression than PRP. Cytokine quantification from supernatant fluids revealed that HAS treatment of inflamed co-cultures significantly reduced levels of IL-5, IL-15, IL-2, TNFα, IL-7 and IL-12. To conclude, lyophilized HAS is a stable and standardized therapeutic with high potential in joint regeneration.

Regenerative Potential of Blood-Derived Products in 3D Osteoarthritic Chondrocyte Culture System

Intra-articular injection of different types of blood-derived products is gaining popularity and clinical importance in the treatment of degenerative cartilage disorders such as osteoarthritis. The regenerative potential of two types of platelet-rich plasma (PRP), prepared in the presence of EDTA (EPRP) and citrate (CPRP) and an alternative blood product-hyperacute serum (hypACT) was evaluated using a 3D osteoarthritic chondrocyte pellet model by assessing the metabolic cell activity, cartilage-related gene expression and extracellular matrix deposition within the pellets. Chondrocyte viability was determined by XTT assay and it revealed no significant difference in metabolic activity of OA chondrocyte pellets after supplementation with different blood products. Nevertheless, the selection of blood products influenced the cartilage-related genes expression, ECM morphology and the tissue quality of pellets. Both PRP types had a different biological effect depending upon concentration and even though CPRP is widely used in clinics our assessment did not reveal good results in gene expression either tissue quality. HypACT supplementation resulted in superior cartilage-related genes expression together with tissue quality and seemed to be the most stable product since no remarkable changes were observed between the two different concentrations. All in all, for successful regenerative therapy, possible molecular mechanisms induced by blood-derived products should be always carefully investigated and adapted to the specific medical indications.

Reevolution of Tissue Regeneration: From Recent Advances in Adipose Stem Cells to Novel Therapeutic Approaches

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