Adipose-Derived Mesenchymal Stem Cells in the Use of Cartilage Tissue Engineering: The Need for a Rapid Isolation Procedure

Fabrication of a Novel 3D Extrusion Bioink Containing Processed Human Articular Cartilage Matrix for Cartilage Tissue Engineering

Cartilage damage presents a significant clinical challenge due to its intrinsic avascular nature which limits self-repair. Addressing this, our study focuses on an alginate-based bioink, integrating human articular cartilage, for cartilage tissue engineering. This novel bioink was formulated by encapsulating C20A4 human articular chondrocytes in sodium alginate, polyvinyl alcohol, gum arabic, and cartilage extracellular matrix powder sourced from allograft femoral condyle shavings. Using a 3D bioprinter, constructs were biofabricated and cross-linked, followed by culture in standard medium. Evaluations were conducted on cellular viability and gene expression at various stages. Results indicated that the printed constructs maintained a porous structure conducive to cell growth. Cellular viability was 87% post printing, which decreased to 76% after seven days, and significantly recovered to 86% by day 14. There was also a notable upregulation of chondrogenic genes, COL2A1 (p = 0.008) and SOX9 (p = 0.021), suggesting an enhancement in cartilage formation. This study concludes that the innovative bioink shows promise for cartilage regeneration, demonstrating substantial viability and gene expression conducive to repair and suggesting its potential for future therapeutic applications in cartilage repair.

Comparative Analysis of Stromal Vascular Fraction and Alternative Mechanisms in Bone Fracture Stimulation to Bridge the Gap between Nature and Technological Advancement: A Systematic Review

BACKGROUND

Various stimulation methods, including electrical, ultrasound, mechanical, and biological interventions, are explored, each leveraging intricate cellular and molecular dynamics to expedite healing. The advent of stromal vascular fraction (SVF) marks a significant stride, offering multifarious benefits in bone healing, from enhanced bone formation to optimal vascular integration, drawing a harmonious balance between innate mechanisms and scientific advancements.

METHODS

This systematic review was conducted focusing on literature from 2016 to 2023 and encompassing various bone healing stimulation mechanisms like SVF, electrical, ultrasound, and mechanical stimulation. The extracted data underwent meticulous synthesis and analysis, emphasizing comparative evaluations of mechanisms, applications, and outcomes of each intervention.

RESULTS

The reviewed studies reveal the potential of SVF in bone fracture healing, with its regenerative and anti-inflammatory effects. The purification of SVF is crucial for safe therapeutic use. Characterization involves flow cytometry and microscopy. Studies show SVF's efficacy in bone regeneration, versatility in various contexts, and potential for clinical use. SVF appears superior to electrical, ultrasound, and mechanical stimulation, with low complications.

CONCLUSIONS

This review compares bone healing methods, including SVF. It provides valuable insights into SVF's potential for bone regeneration. However, due to limited human studies and potential bias, cautious interpretation is necessary. Further research is essential to validate these findings and determine the optimal SVF applications in bone healing.

Analyzing the Clinical Potential of Stromal Vascular Fraction: A Comprehensive Literature Review

Background: Regenerative medicine is evolving with discoveries like the stromal vascular fraction (SVF), a diverse cell group from adipose tissue with therapeutic promise. Originating from fat cell metabolism studies in the 1960s, SVF's versatility was recognized after demonstrating multipotency. Comprising of cells like pericytes, smooth muscle cells, and, notably, adipose-derived stem cells (ADSCs), SVF offers tissue regeneration and repair through the differentiation and secretion of growth factors. Its therapeutic efficacy is due to these cells' synergistic action, prompting extensive research. Methods: This review analyzed the relevant literature on SVF, covering its composition, action mechanisms, clinical applications, and future directions. An extensive literature search from January 2018 to June 2023 was conducted across databases like PubMed, Embase, etc., using specific keywords. Results: The systematic literature search yielded a total of 473 articles. Sixteen articles met the inclusion criteria and were included in the review. This rigorous methodology provides a framework for a thorough and systematic analysis of the existing literature on SVF, offering robust insights into the potential of this important cell population in regenerative medicine. Conclusions: Our review reveals the potential of SVF, a heterogeneous cell mixture, as a powerful tool in regenerative medicine. SVF has demonstrated therapeutic efficacy and safety across disciplines, improving pain, tissue regeneration, graft survival, and wound healing while exhibiting immunomodulatory and anti-inflammatory properties.

Stromal Vascular Fraction Therapy for Knee Osteoarthritis: A Systematic Review

Background and Objectives: Knee osteoarthritis (OA) is a widespread joint disease, set to increase due to aging and rising obesity. Beyond cartilage degeneration, OA involves the entire joint, including the synovial fluid, bones, and surrounding muscles. Existing treatments, such as NSAIDs and corticosteroid injections, mainly alleviate symptoms but can have complications. Joint replacement surgeries are definitive but carry surgical risks and are not suitable for all. Stromal vascular fraction (SVF) therapy is a regenerative approach using cells from a patient's adipose tissue. SVF addresses as degenerative and inflammatory aspects, with potential for cartilage formation and tissue regeneration. Unlike traditional treatments, SVF may reverse OA changes. Being autologous, it reduces immunogenic risks. Materials and Methods: A systematic search was undertaken across PubMed, Medline, and Scopus for relevant studies published from 2017 to 2023. Keywords included "SVF", "Knee Osteoarthritis", and "Regenerative Medicine". Results: This systematic search yielded a total of 172 articles. After the removal of duplicates and an initial title and abstract screening, 94 full-text articles were assessed for eligibility. Of these, 22 studies met the inclusion criteria and were subsequently included in this review. Conclusions: This review of SVF therapy for knee OA suggests its potential therapeutic benefits. Most studies confirmed its safety and efficacy, and showed improved clinical outcomes and minimal adverse events. However, differences in study designs and sizes require a careful interpretation of the results. While evidence supports SVF's positive effects, understanding methodological limitations is key. Incorporating SVF is promising, but the approach should prioritize patient safety and rigorous research.

Efficacy and Long-Term Outcomes of Intra-Articular Autologous Micro-Fragmented Adipose Tissue in Individuals with Glenohumeral Osteoarthritis: A 36-Month Follow-Up Study

BACKGROUND

Glenohumeral osteoarthritis (GOA) is associated with disabling shoulder pain that affects everyday life. Its management comprises various treatment approaches, both conservative and surgical. Regenerative medicine has gained a major role in the conservative treatment of osteoarthritis. Intra-articular injection of adipose-derived mesenchymal stem cells (ADMSCs) is a widely used regenerative medicine approach. The aim of this retrospective study was to report the safety and clinical outcomes of intra-articular injection of ADMSCs in patients with GOA over 36-months.

METHODS

This retrospective observational study involved patients with chronic shoulder pain resistant to standard conservative treatment and a diagnosis of concentric GOA, who received an intra-articular injection of autologous micro-fragmented adipose tissue (μFAT). The values of the Constant-Murley score (CMS), the visual analog scale (VAS), and the simple shoulder test (SST), collected at baseline and at 12, 24, and 36 months, were analyzed to assess treatment efficacy. The single assessment numeric evaluation (SANE) was used to rate patient satisfaction. The Friedman test was used to compare observations of CMS, VAS, and SST values repeated on the same subjects. The significance threshold was set at 0.05.

RESULTS

The participants were 65 patients with a mean age of 54.19 years and a nearly equal gender distribution. Most had mild concentric GOA classified as Samilson-Prieto grade 1. The mean follow-up duration was 44.25 months. The postoperative clinical scores showed significant improvement. At 36 months, the CMS was 84.60, the VAS score was 3.34, and the SST score was 10.15 (all p < 0.0001). The SANE score at 36 months indicated that 54 patients (83.08%) were completely satisfied with the treatment.

CONCLUSION

ADMSC treatment exerted favorable effects on the clinical outcomes of patients with GOA, providing pain relief and improving shoulder function. Our data support its use as a conservative treatment option for osteoarthritis.

The protective effects of hyperoxic pre-treatment in human-derived adipose tissue mesenchymal stem cells against in vitro oxidative stress and a rat model of renal ischaemia-reperfusion

Objective: Improvement of cell survival is essential for achieving better clinical outcomes in stem cell therapy. We investigated the effects of hyperoxic pre-treatment (HP) on the viability of human adipose stromal stem cells (ASCs).Materials and Methods: MTT and Western blot tests were used to assess cell viability and the expression of apoptosis-related proteins, respectively. For the in-vivo trial, the rats were subjected to renal ischaemia-reperfusion (IR).Results: The results showed that HP could significantly increase the viability of ASCs and decrease apoptotic markers (Bax/BCL-2 ratio and Caspase-3) compared with control cells. There were some additional effects with regard to the improvement of renal structure and function in the animal model. However, the difference between the treated and non-treated transplanted ASCs failed to reach significance.Conclusion: These results suggested that HP could increase the survival of ASCs against oxidative stress-induced damages in the in-vitro condition, but this strategy was not highly effective in renal IR.

Auricular cartilage regeneration using different types of mesenchymal stem cells in rabbits

BACKGROUND

Cartilaginous disorders comprise a wide range of diseases that affect normal joint movement, ear and nose shape; and they have great social and economic impact. Mesenchymal stem cells (MSCs) provide a promising regeneration alternative for treatment of degenerative cartilaginous disorders. This study aimed to compare therapeutic potential of different types of laser activated MSCs to promote auricular cartilage regeneration. Twelve adult rabbit allocated equally in four groups, all animals received a surgical mid auricular cartilage defect in one ear; Group I (Positive control) injected sub-perichondrially with phosphate-buffered saline (PBS), Group II (ADMSC-transplanted group) injected adipose-derived MSCs (ADMSCs), Group III (BMMSCs-transplanted group) received bone marrow-derived MSCs (BMMSCs), and Group IV (EMSC-transplanted group) received ear MSCs (EMSCs) in the defected ear. The auricular defect was analyzed morphologically, histopathologically and immunohistochemically after 4 weeks. In addition, a quantitative real-time polymerase chain reaction was used to examine expression of the collagen type II (Col II) and aggrecan as cartilage growth factors.

RESULTS

The auricles of all treatments appeared completely healed with smooth surfaces and similar tissue color. Histopathologically, defective areas of control positive group, ADMSCs and EMSCs treated groups experienced a small area of immature cartilage. While BMMSCs treated group exhibited typical features of new cartilage formation with mature chondrocytes inside their lacunae and dense extracellular matrix (ECM). In addition, BMMSC treated group showed a positive reaction to Masson's trichrome and orcein stains. In contrary, control positive, ADMSC and EMSC groups revealed faint staining with Masson's trichrome and Orcein. Immunohistochemically, there was an intense positive S100 expression in BMMSCs (with a significant increase of area percentage + 21.89 (P < 0.05), a moderate reaction in EMSCs (with an area percentage + 17.97, and a mild reaction in the control group and ADMSCs (area percentages + 8.02 and + 11.37, respectively). The expression of relative col II and aggrecan was substantially highest in BMMSCs (± 0.91 and ± 0.89, respectively). While, Control positive, ADMSCs and EMSCs groups recorded (± 0.41: ± 0.21, ± 0.6: ± 0.44, ± 0.61: ± 0.63) respectively.

CONCLUSION

BMMSCs showed the highest chondrogenic potential compared to ADMSCs and EMSCs and should be considered the first choice in treatment of cartilaginous degenerative disorders.

Within or Without You? A Perspective Comparing In Situ and Ex Situ Tissue Engineering Strategies for Articular Cartilage Repair

Human articular cartilage has a poor ability to self-repair, meaning small injuries often lead to osteoarthritis, a painful and debilitating condition which is a major contributor to the global burden of disease. Existing clinical strategies generally do not regenerate hyaline type cartilage, motivating research toward tissue engineering solutions. Prospective cartilage tissue engineering therapies can be placed into two broad categories: i) Ex situ strategies, where cartilage tissue constructs are engineered in the lab prior to implantation and ii) in situ strategies, where cells and/or a bioscaffold are delivered to the defect site to stimulate chondral repair directly. While commonalities exist between these two approaches, the core point of distinction-whether chondrogenesis primarily occurs "within" or "without" (outside) the body-can dictate many aspects of the treatment. This difference influences decisions around cell selection, the biomaterials formulation and the surgical implantation procedure, the processes of tissue integration and maturation, as well as, the prospects for regulatory clearance and clinical translation. Here, ex situ and in situ cartilage engineering strategies are compared: Highlighting their respective challenges, opportunities, and prospects on their translational pathways toward long term human cartilage repair.

Stem cell therapy in the treatment of organic and dysfunctional endometrial pathology

BACKGROUND

Intrauterine adhesions caused by postpartum curettage, spontaneous abortions, interrupted pregnancies, endometrial ablations, infections and inflammations, can lead to a loss of endometrial function, with consequent hypomenorrhea and infertility in women of reproductive age. In a non-negligible percentage of cases, the available surgical methods and hormone therapy, with sequential administration of estrogen and progesterone, are ineffective. In fact, severe damage to the basal layer of the endometrium causes the loss of endometrial cell precursors and leads to the failure of regeneration of the functional layer to which the endometrium is cyclically exposed. Today, many researchers are evaluating the use of stem cells of different origins as a potential therapy to restore endometrial function.

METHODS

Our interest has been focused on adipose-derived stromal/stem cells (ADSCs) obtained by collecting subcutaneous adipose tissue and subsequently treating it with the MilliGraft^® method. This procedure produces a cell suspension, the stromal vascular fraction (SVF), which includes ADSCs and soluble factors such as proteins and extracellular vesicles (exosomes). The SVF thus obtained was characterized in its cellular composition and its functional factors. Our clinical protocol for the future use of adipose tissue in endometrial regeneration in its different phases is presented.

RESULTS

The data obtained, even though they still require further support and implementation, show the regenerative properties of SVF obtained from adipose tissue using a mechanical method.

CONCLUSIONS

These findings can contribute to the development of cell therapies using stem cells of different derivations which are increasingly being utilized in the treatment of endometrial lesions from adherent or dysfunctional pathologies.

Towards Clinical Translation of In Situ Cartilage Engineering Strategies: Optimizing the Critical Facets of a Cell-Laden Hydrogel Therapy

BACKGROUND

Articular cartilage repair using implantable photocrosslinkable hydrogels laden with chondrogenic cells, represents a promising in situ cartilage engineering approach for surgical treatment. The development of a surgical procedure requires a minimal viable product optimized for the clinical scenario. In our previous work we demonstrated how gelatin based photocrosslinkable hydrogels in combination with infrapatellar derived stem cells allow the production of neocartilage in vitro. In this study, we aim to optimize the critical facets of the in situ cartilage engineering therapy: the cell source, the cell isolation methodology, the cell expansion protocol, the cell number, and the delivery approach.

METHODS

We evaluated the impact of the critical facets of the cell-laden hydrogel therapy in vitro to define an optimized protocol that was then used in a rabbit model of cartilage repair. We performed cells counting and immunophenotype analyses, chondrogenic potential evaluation via immunostaining and gene expression, extrusion test analysis of the photocrosslinkable hydrogel, and clinical assessment of cartilage repair using macroscopic and microscopic scores.

RESULTS

We identified the adipose derived stem cells as the most chondrogenic cells source within the knee joint. We then devised a minimally manipulated stem cell isolation procedure that allows a chondrogenic population to be obtained in only 85 minutes. We found that cell expansion prior to chondrogenesis can be reduced to 5 days after the isolation procedure. We characterized that at least 5 million of cells/ml is needed in the photocrosslinkable hydrogel to successfully trigger the production of neocartilage. The maximum repairable defect was calculated based on the correlation between the number of cells retrievable with the rapid isolation followed by 5-day non-passaged expansion phase, and the minimum chondrogenic concentration in photocrosslinkable hydrogel. We next optimized the delivery parameters of the cell-laden hydrogel therapy. Finally, using the optimized procedure for in situ tissue engineering, we scored superior cartilage repair when compared to the gold standard microfracture approach.

CONCLUSION

This study demonstrates the possibility to repair a critical size articular cartilage defect by means of a surgical streamlined procedure with optimized conditions.

Stem Cells and Organs-on-chips: New Promising Technologies for Human Infertility Treatment

Having biological children remains an unattainable dream for most couples with reproductive failure or gonadal dysgenesis. The combination of stem cells with gene editing technology and organ-on-a-chip models provides a unique opportunity for infertile patients with impaired gametogenesis caused by congenital disorders in sex development or cancer survivors. But how will these technologies overcome human infertility? This review discusses the regenerative mechanisms, applications, and advantages of different types of stem cells for restoring gametogenesis in infertile patients, as well as major challenges that must be overcome before clinical application. The importance and limitations of in vitro generation of gametes from patient-specific human-induced pluripotent stem cells (hiPSCs) will be discussed in the context of human reproduction. The potential role of organ-on-a-chip models that can direct differentiation of hiPSC-derived primordial germ cell-like cells to gametes and other reproductive organoids is also explored. These rapidly evolving technologies provide prospects for improving fertility to individuals and couples who experience reproductive failure.

Fused Cells between Human-Adipose-Derived Mesenchymal Stem Cells and Monocytes Keep Stemness Properties and Acquire High Mobility

Human-adipose-derived mesenchymal stem cells (hADMSCs) are multipotent stem cells which have become of great interest in stem-cell therapy due to their less invasive isolation. However, they have limited migration and short lifespans. Therefore, understanding the mechanisms by which these cells could migrate is of critical importance for regenerative medicine. Methods: Looking for novel alternatives, herein, hADMSCs were isolated from adipose tissue and co-cultured with human monocytes ex vivo. Results: A new fused hybrid entity, a foam hybrid cell (FHC), which was CD90⁺CD14⁺, resulted from this co-culture and was observed to have enhanced motility, proliferation, immunomodulation properties, and maintained stemness features. Conclusions: Our study demonstrates the generation of a new hybrid cellular population that could provide migration advantages to MSCs, while at the same time maintaining stemness properties.

Roles of Cartilage-Resident Stem/Progenitor Cells in Cartilage Physiology, Development, Repair and Osteoarthritis

Osteoarthritis (OA) is a degenerative disease that causes irreversible destruction of articular cartilage for which there is no effective treatment at present. Although articular cartilage lacks intrinsic reparative capacity, numerous studies have confirmed the existence of cartilage-resident stem/progenitor cells (CSPCs) in the superficial zone (SFZ) of articular cartilage. CSPCs are characterized by the expression of mesenchymal stromal cell (MSC)-related surface markers, multilineage differentiation ability, colony formation ability, and migration ability in response to injury. In contrast to MSCs and chondrocytes, CSPCs exhibit extensive proliferative and chondrogenic potential with no signs of hypertrophic differentiation, highlighting them as suitable cell sources for cartilage repair. In this review, we focus on the organizational distribution, markers, cytological features and roles of CSPCs in cartilage development, homeostasis and repair, and the application potential of CSPCs in cartilage repair and OA therapies.

An update of current therapeutic approach for Intervertebral Disc Degeneration: A review article

Intervertebral disc degeneration is a natural process of aging. It can cause physical, psychological, and socioeconomic impact due to the decreasing function of the spine and pain manifestation. Conservative and surgical treatment to correct symptoms and structural anomalies does not fully recover the degenerated disc. Several therapeutic approaches have been developed to improve the clinical result and patient's quality of life. This paper aims to review previous studies that discussed potential novel approach in order to make effective degenerated disc restoration. We tried to briefly describe IVD, IDD, also review several promising current therapeutic approaches for degenerated disc treatment, including its relevance to the degeneration process and limitation to be applied in a clinical setting. There are generally four current therapeutic approaches that we reviewed; growth factors, small molecules, gene therapy, and stem cells. These new approaches aim to not only correct the symptoms but also restore and delay the degeneration process.

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Intervertebral Disc Degeneration.

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Current Therapeutic Approach.

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Stem Cell Therapy.

Mesenchymal Stem Cell-Based Therapy as a New Approach for the Treatment of Systemic Sclerosis

Systemic sclerosis (SSc) is an intractable autoimmune disease with unmet medical needs. Conventional immunosuppressive therapies have modest efficacy and obvious side effects. Targeted therapies with small molecules and antibodies remain under investigation in small pilot studies. The major breakthrough was the development of autologous haematopoietic stem cell transplantation (AHSCT) to treat refractory SSc with rapidly progressive internal organ involvement. However, AHSCT is contraindicated in patients with advanced visceral involvement. Mesenchymal stem cells (MSCs) which are characterized by immunosuppressive, antifibrotic and proangiogenic capabilities may be a promising alternative option for the treatment of SSc. Multiple preclinical and clinical studies on the use of MSCs to treat SSc are underway. However, there are several unresolved limitations and safety concerns of MSC transplantation, such as immune rejections and risks of tumour formation, respectively. Since the major therapeutic potential of MSCs has been ascribed to their paracrine signalling, the use of MSC-derived extracellular vesicles (EVs)/secretomes/exosomes as a "cell-free" therapy might be an alternative option to circumvent the limitations of MSC-based therapies. In the present review, we overview the current knowledge regarding the therapeutic efficacy of MSCs in SSc, focusing on progresses reported in preclinical and clinical studies using MSCs, as well as challenges and future directions of MSC transplantation as a treatment option for patients with SSc.

Three-Dimensional Printing Strategies for Irregularly Shaped Cartilage Tissue Engineering: Current State and Challenges

Although there have been remarkable advances in cartilage tissue engineering, construction of irregularly shaped cartilage, including auricular, nasal, tracheal, and meniscus cartilages, remains challenging because of the difficulty in reproducing its precise structure and specific function. Among the advanced fabrication methods, three-dimensional (3D) printing technology offers great potential for achieving shape imitation and bionic performance in cartilage tissue engineering. This review discusses requirements for 3D printing of various irregularly shaped cartilage tissues, as well as selection of appropriate printing materials and seed cells. Current advances in 3D printing of irregularly shaped cartilage are also highlighted. Finally, developments in various types of cartilage tissue are described. This review is intended to provide guidance for future research in tissue engineering of irregularly shaped cartilage.

Therapeutic Effect of Stem Cells on Male Infertility in a Rat Model: Histological, Molecular, Biochemical, and Functional Study

Methotrexate (MTX) is a folic acid antagonist, widely used as a chemotherapeutic and immunosuppressive drug, but it is toxic to reproductive systems. In recent years, the era of stem cell applications becomes a promising point as a possible therapeutic agent in male infertility. This study is aimed at evaluating the therapeutic effects of stem cells at histological, molecular, biochemical, and functional levels in a methotrexate-induced testicular damage model. Material and Methods. Thirty rats were divided randomly into three groups (ten rats each): group 1 (control): animals received an intraperitoneal injection of 2 ml phosphate-buffered saline per week for 4 weeks, group 2 (MTX-treated group): animals were intraperitoneally injected with methotrexate (8 mg/kg) once weekly for 4 weeks, and group 3 (ADMSC-treated group): methotrexate-treated animals received a single dose of 1 × 10⁶ stem cells/rat at the 5th week. At the 8th week, blood samples were collected for hormonal analysis; then, animals were sacrificed. The testes were dissected; the right testis was stained with hematoxylin and eosin. Random sections were taken from group 3 and examined with a fluorescent microscope. The left testis was divided into two specimens: the first was used for an electron microscope and the second was homogenized for molecular and biochemical assessments. Results. Group 2 showed significant histological changes, decreased free testosterone level, decrease in stem cell factor expression, and dysfunction of the oxidation state. The results revealed significant improvement of these parameters. Conclusion. Transplantation of adipose tissue-derived stem cells (ADMSCs) can improve the testicular damage histologically and functionally in a rat model.

Characterization of wild-type and STAT3 signaling-suppressed mesenchymal stem cells obtained from hemovac blood concentrates

Background

Venous blood drained from the knee joint after total knee arthroplasty (TKA) using a hemovac line is a potential source of bone marrow components, including stem cells, from the cutting surface of cancellous bones of the knee joint. However, the function of mesenchymal stem cells (MSCs) in patients with osteoarthritis (OA-MSCs) can be disrupted by inflammation of the joint. Further, to override the invasive nature of the currently used methods to obtain stem cells, their functional modification is necessary for therapeutic applications.

Methods

The effects of signal transducer and activator of transcription 3 (STAT3) signaling suppression on MSCs (iSTAT3-MSCs) were evaluated by comparative analyses of the characteristics of OA-MSCs and iSTAT3-MSCs from 20 patients who underwent TKA.

Results

OA-MSCs and iSTAT3-MSCs were adherent, with fibroblast-like appearance and high rates of expression of MSC-specific markers, including CD73, CD90, and CD105 (>90%). Both OA-MSCs and iSTAT3-MSCs were able to differentiate into osteogenic, adipogenic, and chondrogenic cells; however, iSTAT3-MSCs showed higher levels of osteogenic and chondrogenic differentiation markers than OA-MSCs. Additionally, the anti-inflammatory and chondroprotective cytokine levels were higher in iSTAT3-MSCs than in OA-MSCs.

Conclusions

These findings indicate that iSTAT3-MSCs after TKA are potentially effective for stem cell therapy in the context of bone and cartilage disorders.

The Effects of Mesenchymal Stem Cell on Colorectal Cancer

Colorectal cancer (CRC) is a common malignant tumor of the gastrointestinal tract with nonobvious early symptoms and late symptoms of anemia, weight loss, and other systemic symptoms. Its morbidity and fatality rate are next only to gastric cancer, esophageal cancer, and primary liver cancer among digestive malignancies. In addition to the conventional surgical intervention, other therapies such as radiotherapy and chemotherapy and new treatment methods such as biologics and microbiological products have been introduced. As a promising cell therapy, mesenchymal stem cell (MSC) has attracted extensive research attention. MSCs are early undifferentiated pluripotent stem cells, which have the common features of stem cells, including self-replication, self-division, self-renewal, and multidirectional differentiation. MSCs come from a wide range of sources and can be extracted from a variety of tissues such as the bone marrow, umbilical cord, and fat. Current studies have shown that MSCs have a variety of biological functions such as immune regulation, tissue damage repair, and therapeutic effects on tumors such as CRC. This review outlines the overview of MSCs and CRC and summarizes the role of MSC application in CRC.

Comparison of Pluripotency, Differentiation, and Mitochondrial Metabolism Capacity in Three-Dimensional Spheroid Formation of Dental Pulp-Derived Mesenchymal Stem Cells

Mesenchymal stem cells (MSCs) are valuable candidates in tissue engineering and stem cell-based therapy. Traditionally, MSCs derived from various tissues have been successfully expanded in vitro using adherent culture plates commonly called as monolayer two-dimensional (2D) cultures. Recently, many studies demonstrated that stemness and multilineage differentiation potential could be enhanced to greater extent when MSCs are cultured as suspended aggregates by means of three-dimensional (3D) culturing techniques. However, there are limited reports on changed mitochondrial metabolism on 3D spheroid formation of MSCs. Therefore, the present study was aimed at investigating the stemness, differentiation potential, and mitochondrial metabolism capacity of 3D dental pulp-derived MSC (DPSC) spheroids in comparison to monolayer cultured DPSCs. We isolated dental pulp-derived MSCs (DPSCs) and successfully developed a 3D culture system which facilitated the formation of MSC spheroids. The cell aggregation was observed after 2 hours, and spheroids were formed after 24 hours and remained in shape for 72 hours. After spheroid formation, the levels of pluripotent markers increased along with enhancement in adipogenic and osteogenic potential compared to 2D cultured control cells. However, decreased proliferative capacity, cell cycle arrest, and elevated apoptosis rate were observed with the time course of the 3D culture except for the initial 24-hour aggregation. Furthermore, oxygen consumption rates of living cells decreased with the time course of the aggregation except for the initial 24 hours. Overall, our study indicated that the short-term 3D culture of MSCs could be a suitable alternative to culture the cells.

Comparison of the Characteristics of Breast Milk-derived Stem Cells with the Stem Cells Derived from the Other Sources: A Comparative Review

Breast milk (BrM) not only supplies nutrition, but it also contains a diverse population of cells. It has been estimated that up to 6% of the cells in human milk possess the characteristics of mesenchymal stem cells (MSC). Available data also indicate that these cells are multipotent and capable of self-renewal and differentiation with other cells. In this review, we have compared different characteristics, such as CD markers, differentiation capacity, and morphology of stem cells, derived from human breast milk (hBr-MSC) with human bone marrow (hBMSC), Wharton's jelly (WJMSC), and human adipose tissue (hADMSC). Through the literature review, it was revealed that human breast milk-derived stem cells specifically express a group of cell surface markers, including CD14, CD31, CD45, and CD86. Importantly, a group of markers, CD13, CD29, CD44, CD105, CD106, CD146, and CD166, were identified, which were common in the four sources of stem cells. WJMSC, hBMSC, hADMSC, and hBr-MSC are potently able to differentiate into the mesoderm, ectoderm, and endoderm cell lineages. The ability of hBr-MSCs todifferentiate into the neural stem cells, neurons, adipocyte, hepatocyte, chondrocyte, osteocyte, and cardiomyocytes has made these cells a promising source of stem cells in regenerative medicine, while isolation of stem cells from the commonly used sources, such as bone marrow, requires invasive procedures. Although autologous breast milk-derived stem cells are an accessible source for women who are in the lactation period, breast milk can be considered as a source of stem cells with high differentiation potential without any ethical concern.

Quantification of Antibody Persistence for Cell Surface Protein Labeling

Introduction

Antibodies are an essential research tool for labeling surface proteins but can potentially influence the behavior of proteins and cells to which they bind. Because of this, researchers and clinicians are interested in the persistence of these antibodies, particularly for live-cell applications. We developed an easily adoptable method for researchers to characterize antibody removal timelines for any cell-antibody combination, with the benefit of studying broad, hypothesized mechanisms of antibody removal.

Methods

We developed a method using four experimental conditions to elucidate the contributions of possible factors influencing antibody removal: cell proliferation, internalization, permanent dissociation, and environmental perturbation. This method was tested on adipose-derived stem cells and a human lung fibroblast cell line with anti-CD44, CD90, and CD105 antibodies. The persistence of the primary antibody was probed using a fluorescent secondary antibody daily over 10 days. Relative contributions by the antibody removal mechanisms were quantified based on differences between the four culture conditions.

Results

Greater than 90% of each antibody tested was no longer present on the surface of the two cell types after 5 days, with removal observed in as little as 1 day post-labeling. Anti-CD90 antibody was primarily removed by environmental perturbation, anti-CD105 antibody by internalization, and anti-CD44 antibody by a combination of all four factors.

Conclusions

Antibody removal mechanism depended on the specific antibody tested, while removal timelines for the same antibody depended more on cell type. This method should be broadly relevant to researchers interested in quantifying an initial timeframe for uninhibited use of antibody-labeled cells.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12195-021-00670-3.

Comparison of Osteogenic Differentiation Potential of Human Dental-Derived Stem Cells Isolated from Dental Pulp, Periodontal Ligament, Dental Follicle, and Alveolar Bone

Background

Mesenchymal stem cells (MSCs) have become promising candidates for regeneration medicine due to their multidifferentiation potential and immunomodulatory ability. Compared with classic MSCs derived from the bone marrow and fat, dental-derived MSCs show high plasticity, accessibility, and applicability. Therefore, they are considered alternative sources for regeneration medicine.

Methods

Four types of MSCs were isolated from the dental pulp, periodontal ligament, dental follicle, and alveolar bone of the same donor, and there were five different individuals. We analyzed their morphology, immunophenotype, proliferation rate, apoptosis, trilineage differentiation potential, and the gene expression during osteogenic differentiation.

Results

Our research demonstrated that DPSCs, PDLSCs, DFPCs and ABMMSCs exhibited similar morphology and immunophenotype. DFPCs showed a higher rate of proliferation and apoptosis. When cultured in the trilineage differentiation medium, all types of MSCs presented the differentiation potential of osteogenesis, adipogenesis, and chondrogenesis. Through staining and genetic analysis during osteogenic induction, ABMMSCs and PDLSCs showed the highest osteogenic ability, followed by DPSCs, and DFPCs were the lowest.

Conclusions

Overall, our results indicated that different dental-derived stem cells possessed different biological characteristics. For bone tissue engineering, ABMMSCs and PDLSCs can be used as optimal candidates of seed cells.

Glenohumeral Osteoarthritis: The Role for Orthobiologic Therapies: Platelet-Rich Plasma and Cell Therapies

The glenohumeral (GH) joint ranks third on the list of the large joints that are most commonly affected by osteoarthritis, after the knee and the hip. General nonsurgical modalities, including changes in daily activities, physical therapy, pharmacotherapy, and corticosteroid injections, constitute the mainstay of treatment. Most of these options, however, have shown moderate and short-term effectiveness. Arthroplasty techniques have proven to be successful for elderly patients. Nevertheless, replacement options are not optimal for younger patients because their functional demands are higher and prostheses have a finite life span. This has led to the search for new nonoperative treatment options to target this subgroup of patients. It has been suggested that orthobiologic therapies, including platelet-rich plasma (PRP) and cell therapies, present great promise and opportunity for the treatment of GH osteoarthritis. Despite the promising results that have been shown by cell therapies and PRP for treating degenerative joint conditions, additional studies are needed to provide more definitive conclusions.

[Research progress on effects of high glucose microenvironment on biological activity of adipose-derived stem cells]

Objective

To summarize the research progress of the effects of high glucose microenvironment on the biological activity of adipose-derived stem cells (ADSCs).

Methods

The literature on the high glucose microenvironment and ADSCs at home and abroad in recent years was reviewed, and the effects of high glucose microenvironment on the general characteristics, differentiation potential, angiogenesis, and nerve regeneration of ADSCs were summarized.

Results

The accumulation of advanced glycosylation end products (AGEs) in the high glucose microenvironment led to changes in the biological activities of ADSCs through various pathways, including cell surface markers, proliferation, migration, multi-lineage differentiation, secretory function, and tissue repair ability. The ability of ADSCs to promote angiogenesis and nerve regeneration in high glucose microenvironment is still controversial.

Conclusion

High glucose microenvironment can affect the biological activity of ADSCs, and the effect and mechanism of ADSCs on angiogenesis and nerve regeneration in high glucose microenvironment need to be further studied.

Review of Synthetic and Hybrid Scaffolds in Cartilage Tissue Engineering

Cartilage tissue is under extensive investigation in tissue engineering and regenerative medicine studies because of its limited regenerative potential. Currently, many scaffolds are undergoing scientific and clinical research. A key for appropriate scaffolding is the assurance of a temporary cellular environment that allows the cells to function as in native tissue. These scaffolds should meet the relevant requirements, including appropriate architecture and physicochemical and biological properties. This is necessary for proper cell growth, which is associated with the adequate regeneration of cartilage. This paper presents a review of the development of scaffolds from synthetic polymers and hybrid materials employed for the engineering of cartilage tissue and regenerative medicine. Initially, general information on articular cartilage and an overview of the clinical strategies for the treatment of cartilage defects are presented. Then, the requirements for scaffolds in regenerative medicine, materials intended for membranes, and methods for obtaining them are briefly described. We also describe the hybrid materials that combine the advantages of both synthetic and natural polymers, which provide better properties for the scaffold. The last part of the article is focused on scaffolds in cartilage tissue engineering that have been confirmed by undergoing preclinical and clinical tests.

Epidural fat mesenchymal stem cells: Important microenvironmental regulators in health, disease, and regeneration: Do EF-MSCs play a role in dural homeostasis/maintenance?

Mesenchymal stem cells (MSCs) are present in fat tissues throughout the body, yet little is known regarding their biological role within epidural fat. We hypothesize that debridement of epidural fat and/or subsequent loss of MSCs within this tissue, disrupts homeostasis in the vertebral environment resulting in increased inflammation, fibrosis, and decreased neovascularization leading to poorer functional outcomes post-injury/operatively. Clinically, epidural fat is commonly considered a space-filling tissue with limited functionality and therefore typically discarded during surgery. However, the presence of MSCs within epidural fat suggests that itis more biologically active than historically believed and may contribute to the regulation of homeostasis and regeneration in the dural environment. While the current literature supports our hypothesis, it will require additional experimentation to determine if epidural fat is an endogenous driver of repair and regeneration and if so, this tissue should be minimally perturbed from its original location in the spinal canal. Also see the video abstract here https://youtu.be/MIol_IWK1os.

Chitosan-Hydrogel Polymeric Scaffold Acts as an Independent Primary Inducer of Osteogenic Differentiation in Human Mesenchymal Stromal Cells

Regenerative medicine aims to restore damaged tissues and mainly takes advantage of human mesenchymal stromal cells (hMSCs), either alone or combined with three-dimensional scaffolds. The scaffold is generally considered a support, and its contribution to hMSC proliferation and differentiation is unknown or poorly investigated. The aim of this study was to evaluate the capability of an innovative three-dimensional gelatin–chitosan hybrid hydrogel scaffold (HC) to activate the osteogenic differentiation process in hMSCs. We seeded hMSCs from adipose tissue (AT-hMSCs) and bone marrow (BM-hMSCs) in highly performing HC of varying chitosan content in the presence of growing medium (GM) or osteogenic medium (OM) combined with Fetal Bovine Serum (FBS) or human platelet lysate (hPL). We primarily evaluated the viability and the proliferation of AT-hMSCs and BM-hMSCs under different conditions. Then, in order to analyse the activation of osteogenic differentiation, the osteopontin (OPN) transcript was absolutely quantified at day 21 by digital PCR. OPN was expressed under all conditions, in both BM-hMSCs and AT-hMSCs. Cells seeded in HC cultured with OM+hPL presented the highest OPN transcript levels, as expected. Interestingly, both BM-hMSCs and AT-hMSCs cultured with GM+FBS expressed OPN. In particular, BM-hMSCs cultured with GM+FBS expressed more OPN than those cultured with GM+hPL and OM+FBS; AT-hMSCs cultured with GM+FBS presented a lower expression of OPN when compared with those cultured with GM+hPL, but no significant difference was detected when compared with AT-hMSCs cultured with OM+FBS. No OPN expression was detected in negative controls. These results show the capability of HC to primarily and independently activate osteogenic differentiation pathways in hMCSs. Therefore, these scaffolds may be considered no more as a simple support, rather than active players in the differentiative and regenerative process.

Identifying the Therapeutic Significance of Mesenchymal Stem Cells

The pleiotropic behavior of mesenchymal stem cells (MSCs) has gained global attention due to their immense potential for immunosuppression and their therapeutic role in immune disorders. MSCs migrate towards inflamed microenvironments, produce anti-inflammatory cytokines and conceal themselves from the innate immune system. These signatures are the reason for the uprising in the sciences of cellular therapy in the last decades. Irrespective of their therapeutic role in immune disorders, some factors limit beneficial effects such as inconsistency of cell characteristics, erratic protocols, deviating dosages, and diverse transfusion patterns. Conclusive protocols for cell culture, differentiation, expansion, and cryopreservation of MSCs are of the utmost importance for a better understanding of MSCs in therapeutic applications. In this review, we address the immunomodulatory properties and immunosuppressive actions of MSCs. Also, we sum up the results of the enhancement, utilization, and therapeutic responses of MSCs in treating inflammatory diseases, metabolic disorders and diabetes.

Successful Use of Human AB Serum to Support the Expansion of Adipose Tissue-Derived Mesenchymal Stem/Stromal Cell in a Microcarrier-Based Platform

Mesenchymal stem/stromal cells (MSC) are promising candidates for cell-based therapies and for the promotion of tissue repair, hence the increase of clinical trials in a worldwide scale. In particular, adipose tissue-derived stem/stromal cells (AT MSC) present easy accessibility and a rather straightforward process of isolation, providing a clear advantage over other sources. The high demand of cell doses (millions of cells/kg), needed for infusion in clinical settings, requires a scalable and efficient manufacturing of AT MSC under xenogeneic(xeno)-free culture conditions. Here we describe the successful use of human AB serum [10%(v/v)] as a culture supplement, as well as coating substrate for the expansion of these cells in microcarriers using (i) a spinner flask and (ii) a 500-mL mini-bioreactor (Applikon^TM Biotechnology). Cells were characterized by immunophenotype and multilineage differentiation potential. Upon an initial cell adhesion in the spinner flask of 35 ± 2.5%, culture reached a maximal cell density of 2.6 ± 0.1 × 10⁵ at day 7, obtaining a 15 ± 1-fold increase. The implementation of the culture in the 500-mL mini-bioreactor presented an initial cell adhesion of 22 ± 5%, but it reached maximal cell density of 2.7 ± 0.4 × 10⁵ at day 7, obtaining a 27 ± 8-fold increase. Importantly, in both stirred systems, cells retained their immunophenotype and multilineage differentiation potential (osteo-, chondro- and adipogenic lineages). Overall, the scalability of this microcarrier-based system presented herein is of major importance for the purpose of achieving clinically meaningful cell numbers.

Recent Advance in Source, Property, Differentiation, and Applications of Infrapatellar Fat Pad Adipose-Derived Stem Cells

Infrapatellar fat pad (IPFP) can be easily obtained during knee surgery, which avoids the damage to patients for obtaining IPFP. Infrapatellar fat pad adipose-derived stem cells (IPFP-ASCs) are also called infrapatellar fat pad mesenchymal stem cells (IPFP-MSCs) because the morphology of IPFP-ASCs is similar to that of bone marrow mesenchymal stem cells (BM-MSCs). IPFP-ASCs are attracting more and more attention due to their characteristics suitable to regenerative medicine such as strong proliferation and differentiation, anti-inflammation, antiaging, secreting cytokines, multipotential capacity, and 3D culture. IPFP-ASCs can repair articular cartilage and relieve the pain caused by osteoarthritis, so most of IPFP-related review articles focus on osteoarthritis. This article reviews the anatomy and function of IPFP, as well as the discovery, amplification, multipotential capacity, and application of IPFP-ASCs in order to explain why IPFP-ASC is a superior stem cell source in regenerative medicine.

Human articular cartilage repair: Sources and detection of cytotoxicity and genotoxicity in photo-crosslinkable hydrogel bioscaffolds

Three-dimensional biofabrication using photo-crosslinkable hydrogel bioscaffolds has the potential to revolutionize the need for transplants and implants in joints, with articular cartilage being an early target tissue. However, to successfully translate these approaches to clinical practice, several barriers must be overcome. In particular, the photo-crosslinking process may impact on cell viability and DNA integrity, and consequently on chondrogenic differentiation. In this review, we primarily explore the specific sources of cellular cytotoxicity and genotoxicity inherent to the photo-crosslinking reaction, the methods to analyze cell death, cell metabolism, and DNA damage within the bioscaffolds, and the possible strategies to overcome these detrimental effects.

A simple, efficient and economical method for isolating and culturing human umbilical cord blood‑derived mesenchymal stromal cells

Mesenchymal stromal cells (MSCs) hold broad therapeutic potential in various diseases, however, it is difficult to produce sufficient numbers of MSCs for clinical application, therefore, improved culture systems are required. The present study aimed to develop a novel method for isolating and culturing human umbilical cord blood‑derived mesenchymal stromal cells (hUCB‑MSCs). A sequential culture method was developed that uses two types of culture media to optimize the isolation and culture of hUCB‑MSCs. First, DMEM supplemented with mesenchymal stem cell growth supplement was used to improve the colony formation and primary culture success rates of hUCB‑MSCs. Then, after removing the heterogeneous cell population, ordinary DMEM was used from the fourth passage. This method obtained hUCB‑MSCs with high culture efficiency and at a greatly reduced cost. The optimal culture conditions were determined and the hUCB‑MSCs were phenotypically characterized after passaging. Taken together, this simple, efficient and economical method can produce a large number of high‑quality hUCB‑MSCs in <1 month, therefore facilitating the future clinical applications of hUCB‑MSCs.

Enrichment of CD146+ Adipose-Derived Stem Cells in Combination with Articular Cartilage Extracellular Matrix Scaffold Promotes Cartilage Regeneration

Heterogeneity of mesenchymal stem cells (MSCs) influences the cell therapy outcome and the application in tissue engineering. Also, the application of subpopulations of MSCs in cartilage regeneration remains poorly characterized. CD146+ MSCs are identified as the natural ancestors of MSCs and the expression of CD146 are indicative of greater pluripotency and self-renewal potential. Here, we sorted a CD146⁺ subpopulation from adipose-derived mesenchymal stem cells (ADSCs) for cartilage regeneration.

Methods: CD146⁺ ADSCs were sorted using magnetic activated cell sorting (MACS). Cell surface markers, viability, apoptosis and proliferation were evaluated in vitro. The molecular signatures were analyzed by mRNA and protein expression profiling. By intra-articular injections of cells in a rat osteochondral defect model, we assessed the role of the specific subpopulation in cartilage microenvironment. Finally, CD146⁺ ADSCs were combined with articular cartilage extracellular matrix (ACECM) scaffold for long term (3, 6 months) cartilage repair.

Results: The enriched CD146⁺ ADSCs showed a high expression of stem cell and pericyte markers, good viability, and immune characteristics to avoid allogeneic rejection. Gene and protein expression profiles revealed that the CD146⁺ ADSCs had different cellular functions especially in regulation inflammation. In a rat model, CD146⁺ ADSCs showed a better inflammation-modulating property in the early stage of intra-articular injections. Importantly, CD146⁺ ADSCs exhibited good biocompatibility with the ACECM scaffold and the CD146⁺ cell-scaffold composites produced less subcutaneous inflammation. The combination of CD146⁺ ADSCs with ACECM scaffold can promote better cartilage regeneration in the long term.

Conclusion: Our data elucidated the function of the CD146⁺ ADSC subpopulation, established their role in promoting cartilage repair, and highlighted the significance of cell subpopulations as a novel therapeutic for cartilage regeneration.

Protocols for Culturing and Imaging a Human Ex Vivo Osteochondral Model for Cartilage Biomanufacturing Applications

Cartilage defects and diseases remain major clinical issues in orthopaedics. Biomanufacturing is now a tangible option for the delivery of bioscaffolds capable of regenerating the deficient cartilage tissue. However, several limitations of in vitro and experimental animal models pose serious challenges to the translation of preclinical findings into clinical practice. Ex vivo models are of great value for translating in vitro tissue engineered approaches into clinically relevant conditions. Our aim is to obtain a viable human osteochondral (OC) model to test hydrogel-based materials for cartilage repair. Here we describe a detailed step-by-step framework for the generation of human OC plugs, their culture in a perfusion device and the processing procedures for histological and advanced microscopy imaging. Our ex vivo OC model fulfils the following requirements: the model is metabolically stable for a relevant culture period of 4 weeks in a perfusion bioreactor, the processing procedures allowed for the analysis of 3 different tissues or materials (cartilage, bone and hydrogel) without compromising their integrity. We determined a protocol and the settings for a non-linear microscopy technique on label free sections. Furthermore, we established a clearing protocol to perform light sheet-based observations on the cartilage layer without the need for tedious and destructive histological procedures. Finally, we showed that our OC system is a clinically relevant in terms of cartilage regeneration potential. In conclusion, this OC model represents a valuable preclinical ex vivo tool for studying cartilage therapies, such as hydrogel-based bioscaffolds, and we envision it will reduce the number of animals needed for in vivo testing.

Cartilage Tissue Engineering Using Stem Cells and Bioprinting Technology-Barriers to Clinical Translation

There is no long-term treatment strategy for young and active patients with cartilage defects. Early and effective joint preserving treatments in these patients are crucial in preventing the development of osteoarthritis. Tissue engineering over the past few decades has presented hope in overcoming the issues involved with current treatment strategies. Novel advances in 3D bioprinting technology have promoted more focus on efficient delivery of engineered tissue constructs. There have been promising in-vitro studies and several animal studies looking at 3D bioprinting of engineered cartilage tissue. However, to date there are still no human clinical trials using 3D printed engineered cartilage tissue. This review begins with discussion surrounding the difficulties with articular cartilage repair and the limitations of current clinical management options which have led to research in cartilage tissue engineering. Next, the major barriers in each of the 4 components of cartilage tissue engineering; cells, scaffolds, chemical, and physical stimulation will be reviewed. Strategies that may overcome these barriers will be discussed. Finally, we will discuss the barriers surrounding intraoperative delivery of engineered tissue constructs and possible solutions.