Adipose-derived and bone marrow mesenchymal stem cells: a donor-matched comparison

Amelioration of female menopausal syndrome by intravenous administration of autologous menstrual blood-derived stem cells

Introduction

Menopausal syndrome is characterized by a wide range of physical and psychological symptoms in women aged 40s-50s as a result of hormonal fluctuations and age-related decline. Various treatments have been used to manage the symptoms, including hormone replacement therapy, but no effective causal therapies have yet been identified. Regenerative medicine has gained considerable attention as a promising approach to age-related problems, and mesenchymal stem cell therapies have been extensively studied. Recently, menstrual blood has emerged as a novel cell source of stem cells, called menstrual blood-derived stem cells (MenSCs), due to its non-invasive, regular and consistent collection from women. In this study, we have investigated the therapeutic potential of intravenous administration of autologous MenSCs on female menopausal syndromes.

Methods

Menstrual blood was collected from 15 patients aged 30s-60s with ovarian dysfunction using a menstrual cup, and MenSCs were isolated, cultured and expanded. Patients received either 3 × 107 cells or 1 × 108 cells intravenously 1 to 5 times at intervals of more than 1 month. Patient-reported symptoms were assessed using the Simplified Menopausal Index at pre-treatment and after 1, 3, 6, and 12 months, and safety assessments were performed. Serum estradiol and follicle-stimulating hormone levels were also measured by immunoassay.

Results

Almost all patients who received MenSCs experienced a sharp reduction in menopausal symptoms, including vasomotor, neuropsychiatric, and motor symptoms, one month after the first administration, and these symptoms remained low for 6 months. The Simplified Menopausal Index score was significantly reduced after treatment. The reducing potency of 1 × 108 MenSCs was greater than that of 3 × 107 MenSCs. Patients who received a higher number of MenSCs showed an increasing trend in estradiol levels and a decreasing trend in follicle-stimulating hormone levels. When MenSCs were administered to postmenopausal patients, this trend was more pronounced. Overall, no apparent serious adverse events were observed during these treatments.

Conclusions

The present results suggest that the administration of MenSCs improved menopausal symptoms and regulated hormonal balance without any serious adverse events. This is the first report on the promising therapeutic potential of cell-based therapy using autologous MenSCs for female menopausal syndrome.

Bone marrow mesenchymal stem cells (BMSCs)-derived exosomal METTL3 regulates the m6A methylation of SMAD5 to promote osteogenic differentiation of osteoblasts

BACKGROUND

Methyltransferase-like 3 (METTL3) is implicated in human diseases, including osteoporosis (OP). In this study, we aimed to explore the functions and mechanisms of METTL3 in OP using bone marrow mesenchymal stem cells (BMSCs).

METHODS

The identification of BMSCs-derived exosomes was conducted by transmission electron microscope (TEM), Nanoparticle Tracking Analysis (NTA) and western blot. The osteogenic differentiation of osteoblasts (hFOB1.19) was analyzed by Alizarin red staining assay, Alkaline phosphatase (ALP) staining assay and western blot. The relationship between METTL3 and SMAD family member 5 (SMAD5) was analyzed by Methylated RNA Immunoprecipitation (MeRIP) assay and dual-luciferase reporter assay.

RESULTS

BMSCs-derived exosomes (BMSC-Exos) promoted the osteogenic differentiation and elevated METTL3 expression in hFOB1.19 cells. Exosomal METTL3 knockdown repressed the osteogenic differentiation in hFOB1.19 cells. METTL3 could stabilize and regulate SMAD5 expression by N6-methyladenosine (m6A) modification. Moreover, SMAD5 overexpression restored exosomal METTL3 knockdown-mediated effect on the osteogenic differentiation in hFOB1.19 cells.

CONCLUSION

BMSCs-derived exosomal METTL3 mediated the m6A methylation of SMAD5 to facilitate osteogenic differentiation of hFOB1.19 cells.

[Exosome derived from human adipose-derived mesenchymal stem cells prevented bone loss induced by estrogen deficiency]

OBJECTIVE

To investigate the effect of human adipose-derived mesenchymal stem cells (hASCs) exosomes on osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) extracted from osteoporotic mice, and to evaluate the effect of hASCs exosomes on preventing bone loss induced by estrogen deficiency.

METHODS

hASCs exosomes were extracted by ultracentrifugation. The osteoporotic mice were established by bilateral ovariectomy (OVX). BMSCs were isolated from osteo-porotic mice and cultured for further analysis. In the experimental group, these BMSCs were exposed to an osteogenic induction medium supplemented with hASCs exosomes to evaluate their potential effects on osteogenesis. In contrast, the control group was treated with the same osteogenic induction medium, but without the addition of hASCs exosomes, to serve as a baseline comparison for the study. To comprehensively assess the osteogenic differentiation of BMSCs influenced by hASCs exosomes, alkaline phosphatase (ALP) staining, ALP activity quantitative analysis and quantitative reverse transcription polymerase chain reaction (qPCR) were performed. These evaluations provided critical insights into the role of hASCs exosomes in promoting osteoblast differentiation and bone formation in osteoporotic conditions. The fluorescence labeled hASCs exosomes were injected via the tail vein to observe the biodistribution of exosomes. Two weeks after OVX, the mice were divided into three groups: The experimental group consisted of estrogen-deficient mice receiving hASCs exosome injections; the negative control group consisted of estrogen-deficient mice receiving phosphate-buffered saline (PBS) injections; and the positive control group consisted of mice that underwent Sham surgery and received PBS injections.The injections were administered once every 3 days, for a total of 8 injections. Afterward, the femurs were collected from the mice, and micro-computed tomography (micro-CT) was performed to measure bone mineral density and conduct bone morphometric analysis.

RESULTS

hASCs exosomes were successfully extracted using ultracentrifugation. After the induction by hASCs exosomes, ALP staining and ALP activity in the BMSCs extracted from osteoporotic mice were significantly enhanced, the expression of osteogenesis related genes in BMSCs were significantly up-regulated. More trabecular bone and higher bone mineral density were observed in estrogen-deficient mice injected with hASCs exosomes compared with estrogen-deficient mice injected with PBS, and there was no significant decrease in bone mineral density compared with the Sham operation group.

CONCLUSION

hASCs exosomes promoted the osteogenic differentiation of BMSCs extracted from osteoporotic mice. hASCs exosomes prevented bone loss induced by estrogen deficiency.

Decellularized Porcine Aorta as a Scaffold for Human Induced Pluripotent Stem Cell-Derived Mesenchymal Stem Cells in Tissue Engineering

Tissue engineering has been an integral part of regenerative medicine. Functional biomimetic structures were assembled by combining appropriate scaffolds with specific cells. The decellularization of animal tissue preserved the natural biochemical components and structural properties of the extracellular matrix (ECM) of specific organs, thereby providing a suitable niche for tissue-specific cell differentiation and growth. In this study, the extracellular matrix (ECM) of the porcine aorta was obtained through trypsin-based decellularization. The resulting porcine aortic ECM retained a favorable collagen composition, exhibited no cytotoxicity, and demonstrated chemophilic properties for mesenchymal stem cells. Human adipose-derived mesenchymal stem cells (hADSCs) and human induced pluripotent stem cell-derived mesenchymal stem cells (hiMSCs) were transplanted onto the decellularized porcine aortic ECM, where successful differentiation into a mature cartilage layer was observed. These findings suggested that the porcine aortic ECM could serve as a potential scaffold with tubular and linear structures for tissue engineering applications. Functional human iMSCs (induced-mesenchymal stem cells) were generated from human iPSCs (induced-pluripotent stem cells) and analyzed for differences compared to primary MSCs via RNA-seq. The hiMSCs were applied to decellularized porcine aortic ECM (extracellular matrix), demonstrating chondrogenic differentiation and confirming the usability of xenogeneic ECM.

Engineered 3D mesenchymal stem cell aggregates with multifunctional prowess for bone regeneration: Current status and future prospects

BACKGROUND

Impaired efficacy of in vitro expanded mesenchymal stem cells (MSCs) is a universal and thorny situation, which cast a shadow on further clinical translation of exogenous MSCs. Moreover, the relatively lengthy healing process, host metabolic heterogeneity and the sophisticated cell recognition and crosstalk pose rigorous challenges towards MSC-based bone regeneration strategies. Three-dimensional (3D) cell aggregates facilitate more robust intercellular communications and cell-extracellular matrix (ECM) interactions, providing a better mimicry of microarchitectures and biochemical milieus in vivo, which is conducive for stemness maintenance and downstream bone formation.

AIM OF REVIEW

This review enunciates the phenotypic features of MSCs in aggregates, which deepens the knowledge of the MSC fate determination in 3D microenvironment. By summarizing current empowerment methods and biomaterial-combined techniques for establishing functionalized MSC aggregates, this review aims to spark innovative and promising solutions for exalting the translational value of MSCs and improve their therapeutic applications in bone tissue repair.

KEY SCIENTIFIC CONCEPTS OF REVIEW

3D aggregates optimize regenerative behaviors of in vitro cultured MSCs including cell adhesion, viability, proliferation, pluripotency and immunoregulation capacity, etc. Biomaterials hybridization endows MSC aggregates with tailored mechanical and biological properties, which offers more possibilities in adapting various clinical scenarios.

Adipose stromal cells in the human rotator cuff are resistant to fibrotic microenvironmental cues

Rotator cuff tears are the most common upper extremity orthopaedic injury, causing degenerative changes within the bone, tendon, joint capsule, bursa and muscle. These degenerative changes are linked to poor rehabilitative and surgical outcomes, which has launched investigations into co-therapeutic biologics. Specifically, mesenchymal stem cells (MSCs) have shown promise in mitigating degenerative changes in animal models of rotator cuff tears, but reports of their impact on clinical outcomes remain mixed. Here we describe an alternative source of MSCs in the human shoulder, adipose stromal cells (ASCs) from the subacromial fat (SAF) pad. Compared to the gold-standard subcutaneous (SQ) fat, we show that SAF ASCs are less sensitive to chemical and mechanical fibrotic cues, (1) retaining smaller cell area with reduced actin stress fibre alignment across a range of physiological and pathological stiffnesses, (2) having reduced traction forces and extracellular matrix production, and (3) having reduced myofibroblastic conversion in response to cytokine challenge. Furthermore, we show that SAF ASCs enhance fusion of primary human myoblasts via paracrine signalling. Despite a fibrotic signature in SAF from rotator cuffs with tendon tears, SAF ASCs sourced from torn rotator cuffs were equally effective at resisting fibroblastic conversion and promoting myogenesis as those from intact rotator cuffs, further supporting autologous clinical use of these cells. In conclusion, this study describes human SAF ASCs as an alternative, and potentially superior, cell source for rotator cuff therapies. KEY POINTS: Adipose tissue within the rotator cuff is a novel and understudied source of therapeutic adipose stromal cells. Here, we detail the impact rotator cuff tears have on adipose tissue within the shoulder, its resident adipose stromal cells, and make a comparison of shoulder adipose stromal cells to subcutaneous adipose stromal cells. Rotator cuff tears cause fibrosis of rotator cuff adipose tissue; this fibrosis does not impact downstream adipose stromal cell morphology or pro-myogenic signaling. Rotator cuff adipose stromal cells resist fibrotic microenvironmental cues and have enhanced pro-myogenic paracrine signaling compared with traditional subcutaneous adipose stromal cells. Rotator cuff adipose stromal cells represent a new cell type that can be impactful in advancing rotator cuff therapies.

Electrical Phenotyping of Aged Human Mesenchymal Stem Cells Using Dielectrophoresis

Human mesenchymal stem cells (hMSCs) are widely used in regenerative medicine, but large-scale in vitro expansion alters their function, impacting proliferation and differentiation potential. Currently, a predictive marker to assess these changes is lacking. Here, we used dielectrophoresis (DEP) to characterize the electrical phenotype of hMSCs derived from bone marrow (BM), adipose tissue (AT), and umbilical cord (UC) as they aged in vitro from passage 4 (P4) to passage 9 (P9). The electrical phenotype was defined by the DEP spectra, membrane capacitance, and cytoplasm conductivity. Cell morphology and size, growth characteristics, adipogenic differentiation potential, and osteogenic differentiation potential were assessed alongside label-free biomarker membrane capacitance and cytoplasm conductivity. Differentiation was confirmed by histological staining and RT-qPCR. All hMSCs exhibited typical morphology, though cell size varied, with UC-hMSCs displaying the largest variability across all size metrics. Growth analysis revealed that UC-hMSCs proliferated the fastest. The electrical phenotype varied with cell source and in vitro age, with high passage hMSCs showing noticeable shifts in DEP spectra, membrane capacitance, and cytoplasm conductivity. Correlation analysis revealed that population doubling level (PDL) correlated with membrane capacitance and cytoplasm conductivity, indicating PDL as a more precise marker of in vitro aging than passage number. Additionally, we demonstrate that membrane capacitance correlates with the osteogenic marker COL1A1 and that cytoplasm conductivity correlates with the adipogenic markers ADIPOQ and FABP4, suggesting that DEP-derived electrical properties serve as label-free biomarkers of differentiation potential. While DEP has previously been applied to BM-hMSCs and AT-hMSCs, and more recently to UC-hMSCs, few studies have provided a direct comparison across all three sources or tracked changes across continuous expansion. These findings underscore the utility of DEP as a label-free approach for assessing hMSC aging and function, offering practical applications for optimizing stem cell expansion and stem cell banking in clinical settings.

Physiologically-Modeled Dynamic Stimulation and Growth Factors Induce Differentiation of Mesenchymal Stem Cells to a Vascular Endothelial Cell Phenotype

OBJECTIVE

Mesenchymal stem cells (MSCs) represent an attractive option as an endothelial cell (EC) source for regenerative medicine therapies. However, the differentiation of MSCs toward an ECs phenotype can be regulated by a complex and dynamic microenvironment, including specific growth factors as well as local mechanical cues. The objective of this work was to evaluate whether Physiologically-modeled dynamic stimulation (PMDS) characterized by continuous variability in pulse frequencies mimicking the dynamic temporal range of cardiac function would enhance MSC differentiation toward ECs compared to a constant frequency stimulation.

METHODS

Mesenchymal stem cells were grown in a complex growth factor cocktail versus standard culture media to initiate the endothelial differentiation process, then subsequently exposed to PMDS that vary in duration and constant flow (CF) at a fixed 10 dynes/cm2 shear stress and 1.3 Hz frequency.

RESULTS

Both PMDS and media type strongly influence cell differentiation and function. Cells were shown to significantly upregulate eNOS activity and displayed lower TNF-a induced leukocyte adhesion compared to cells cultured under CF, consistent with a more quiescent ECs phenotype that regulates anti-inflammatory and anti-thrombotic states.

CONCLUSION

These findings suggest that the dynamic microenvironment created by perfusion, in contrast to constant frequency, combined with growth factors, enhances MSCs differentiation toward a vascular endothelial-like phenotype.

Variant-to-function approaches for adipose tissue: Insights into cardiometabolic disorders

Genome-wide association studies (GWASs) have identified thousands of genetic loci associated with cardiometabolic disorders. However, the functional interpretation of these loci remains a daunting challenge. This is particularly true for adipose tissue, a critical organ in systemic metabolism and the pathogenesis of various cardiometabolic diseases. We discuss how variant-to-function (V2F) approaches are used to elucidate the mechanisms by which GWAS loci increase the risk of cardiometabolic disorders by directly influencing adipose tissue. We outline GWAS traits most likely to harbor adipose-related variants and summarize tools to pinpoint the putative causal variants, genes, and cell types for the associated loci. We explain how large-scale perturbation experiments, coupled with imaging and multi-omics, can be used to screen variants' effects on cellular phenotypes and how these phenotypes can be tied to physiological mechanisms. Lastly, we discuss the challenges and opportunities that lie ahead for V2F research and propose a roadmap for future studies.

Non-coding RNA in cartilage regeneration: regulatory mechanism and therapeutic strategies

The pathogenesis of cartilage injury and degeneration is exceptionally complex. In addition to being associated with osteoarthritis and trauma, factors such as age, gender, obesity, inflammation, and apoptosis of chondrocytes are also considered significant influencing factors. Due to the lack of direct blood supply, lymphatic circulation, and neural innervation, coupled with low metabolic activity, the self-repair capability of cartilage after injury is extremely limited, making its treatment quite challenging. Recent research indicated that ncRNA, a class of RNA transcribed from the genome that does not encode proteins, played a crucial regulatory role in various disease processes. Particularly noteworthy is its positive regulatory role in cartilage regeneration, achieved through the modulation of the inflammatory microenvironment, promotion of chondrocyte proliferation, inhibition of chondrocyte degradation, and facilitation of the recruitment and differentiation of bone marrow mesenchymal stem cells into chondrocytes. In the earlier phase, we conducted a review and outlook on therapeutic strategies for the regeneration of articular cartilage injuries. This article specifically focuses on summarizing the regulatory roles and research advancements of ncRNA in cartilage regeneration, as well as its contributions to the clinical application of gene therapy for cartilage defects.

Immunomodulatory effects of mesenchymal stem cell therapy in chronic kidney disease: a literature review

Chronic kidney disease (CKD) has been a growing public medical concern in recent years which calls for effective interventions. Mesenchymal stem cells (MSCs) have garnered increased interest in past decades due to their potential to repair and regenerate damaged tissues. Many clinical trials have highlighted the safety and effectiveness of kidney disease with this novel cell therapy. MSC infusion can improve renal function indices such as glomerular filtration rate, urine protein, serum creatinine, and blood urea nitrogen, while inhibiting immune response by increasing regulatory T cells. The therapeutic mechanisms may be primarily attributed to a function combined with immunomodulation, anti-inflammation, anti-fibrosis, promoting angiogenesis, anti-oxidation, anti-apoptosis, or tissue healing produced by cell secretsome. However, CKD is a broad concept due to many pathological etiologies including diabetes, hypertension, heart disease, immunological damage, a family history of renal failure, and so on. Furthermore, the therapeutic efficacy of MSCs may be influenced by different cell sources, injection methods, medication dosage, or homing proportion. As a result, it is timely and essential to access recent advancements in the MSC application on CKD.

The Regenerative Marriage Between High-Density Platelet-Rich Plasma and Adipose Tissue

The use of autologous biological preparations (ABPs) and their combinations fills the void in healthcare treatment options that exists between surgical procedures, like plastic reconstructive, cosmetic, and orthopedic surgeries; non-surgical musculoskeletal biological procedures; and current pharmaceutical treatments. ABPs, including high-density platelet-rich plasma (HD-PRP), bone marrow aspirate concentrates (BMACs), and adipose tissue preparations, with their unique stromal vascular fractions (SVFs), can play important roles in tissue regeneration and repair processes. They can be easily and safely prepared at the point of care. Healthcare professionals can employ ABPs to mimic the classical wound healing cascade, initiate the angiogenesis cascade, and induce tissue regenerative pathways, aiming to restore the integrity and function of damaged tissues. In this review, we will address combining autologous HD-PRP with adipose tissue, in particular the tissue stromal vascular fraction (t-SVF), as we believe that this biocellular combination demonstrates a synergistic effect, where the HD-PRP constituents enhance the regenerative potential of t-SVF and its adipose-derived mesenchymal stem cells (AD-MSCs) and pericytes, leading to improved functional tissue repair, tissue regeneration, and wound healing in variety of clinical applications. We will address some relevant platelet bio-physiological aspects, since these properties contribute to the synergistic effects of combining HD-PRP with t-SVF, promoting overall better outcomes in chronic inflammatory conditions, soft tissue repair, and tissue rejuvenation.

Bioprinting of mesenchymal stem cells in low concentration gelatin methacryloyl/alginate blends without ionic crosslinking of alginate

Bioprinting allows for the fabrication of tissue-like constructs by precise architecture and positioning of the bioactive hydrogels with living cells. This study was performed to determine the effect of very low concentrations of alginate (0.1, 0.3, and 0.5% w/v) on bioprinting of bone marrow mesenchymal stem cells (BMSC) in gelatin methacryloyl (GelMA; 5% w/v)/alginate blend. Furthermore, while GelMA was photocrosslinked in all bioprinted constructs, the effect of crosslinking alginate with calcium chloride on the physical and biological characteristics of the constructs was investigated. The inclusion of low-concentration alginate improved the viscosity and printability of the formulation as well as the compressive modulus of the hydrogels, particularly when ionically crosslinked with calcium chloride, compared with the group in that alginate was not crosslinked. However, the stability and degradability of 3D printed scaffolds that were only photocrosslinked were comparable to those that were additionally crosslinked with calcium chloride. Noteworthily, ionic crosslinking of alginate deteriorated the viability of BMSC. Morphology and growth of BMSC were improved by adding a low alginate concentration; however, ionic crosslinking of alginate affected these factors adversely. The findings of this study underscore the significance of carefully evaluating the crosslinking strategy used in conjunction with cell-laden GelMA/alginate hydrogel to achieve balanced physical and biological properties as well as less complicated post-bioprinting processing.

Emerging Role of Mesenchymal Stromal Cell and Exosome Therapies in Treating Cognitive Impairment

Cognitive aging, characterized by the gradual decline in cognitive functions such as memory, attention, and problem-solving, significantly impacts daily life. This decline is often accelerated by neurodegenerative diseases, particularly Alzheimer's Disease (AD) and Parkinson's Disease (PD). AD is marked by the accumulation of amyloid-beta plaques and tau tangles, whereas PD involves the degeneration of dopaminergic neurons. Both conditions lead to severe cognitive impairment, greatly diminishing the quality of life for affected individuals. Recent advancements in regenerative medicine have highlighted mesenchymal stromal cells (MSCs) and their derived exosomes as promising therapeutic options. MSCs possess regenerative, neuroprotective, and immunomodulatory properties, which can promote neurogenesis, reduce inflammation, and support neuronal health. Exosomes, nanosized vesicles derived from MSCs, provide an efficient means for delivering bioactive molecules across the blood-brain barrier, targeting the underlying pathologies of AD and PD. While these therapies hold great promise, challenges such as variability in MSC sources, optimal dosing, and effective delivery methods need to be addressed for clinical application. The development of robust protocols, along with rigorous clinical trials, is crucial for validating the safety and efficacy of MSC and exosome therapies. Future research should focus on overcoming these barriers, optimizing treatment strategies, and exploring the integration of MSC and exosome therapies with lifestyle interventions. By addressing these challenges, MSC- and exosome-based therapies could offer transformative solutions for improving outcomes and enhancing the quality of life for individuals affected by cognitive aging and neurodegenerative diseases.

Donor tissue type alters the effects of mesenchymal stem cells on human osteoarthritic chondrocytes and their metabolomic profiles

Early post-traumatic osteoarthritis due to sports injuries is not rare and cell-based therapies are currently used in the treatment. Infrapatellar fat pad (IPFP), synovium (Sy) and subcutaneous adipose (S) tissues were obtained for analysis and MSC isolation. Osteoarthritic (OACs) and normal chondrocytes were co-cultured with MSCs for days seven and 14. Tumour necrosis factor alpha (TNFα), cartilage oligomeric matrix protein (COMP) and matrix metalloproteinase-3 (MMP-3) levels were analysed in the supernatants. Untargeted metabolomic analyses were performed in the collected tissues and co-culture media of the experiment groups. TNFα concentrations were lower in IPFP-MSC and Sy-MSC had lower than OACs on day 14. Likewise, MMP-3 decreased in the same groups on day seven and day 14 (p = 0.036). Metabolomic analysis showed distinct profiles in the tissues and metabolic changes in the co-culture media. The extracellular environment of MSCs derived from the IPFP, Sy and S have distinct features and effects on OACs.

Mesenchymal stem cells and their extracellular vesicle therapy for neurological disorders: traumatic brain injury and beyond

Traumatic brain injury (TBI) is a complex condition involving mechanisms that lead to brain dysfunction and nerve damage, resulting in significant morbidity and mortality globally. Affecting ~50 million people annually, TBI's impact includes a high death rate, exceeding that of heart disease and cancer. Complications arising from TBI encompass concussion, cerebral hemorrhage, tumors, encephalitis, delayed apoptosis, and necrosis. Current treatment methods, such as pharmacotherapy with dihydropyridines, high-pressure oxygen therapy, behavioral therapy, and non-invasive brain stimulation, have shown limited efficacy. A comprehensive understanding of vascular components is essential for developing new treatments to improve blood vessel-related brain damage. Recently, mesenchymal stem cells (MSCs) have shown promising results in repairing and mitigating brain damage. Studies indicate that MSCs can promote neurogenesis and angiogenesis through various mechanisms, including releasing bioactive molecules and extracellular vesicles (EVs), which help reduce neuroinflammation. In research, the distinctive characteristics of MSCs have positioned them as highly desirable cell sources. Extensive investigations have been conducted on the regulatory properties of MSCs and their manipulation, tagging, and transportation techniques for brain-related applications. This review explores the progress and prospects of MSC therapy in TBI, focusing on mechanisms of action, therapeutic benefits, and the challenges and potential limitations of using MSCs in treating neurological disorders.

Small extracellular vesicles derived from sequential stimulation of canine adipose-derived mesenchymal stem cells enhance anti-inflammatory activity

BACKGROUND

Small extracellular vesicles (sEVs) derived from mesenchymal stem cells (MSCs) are recognized for their therapeutic potential in immune modulation and tissue repair, especially in veterinary medicine. This study introduces an innovative sequential stimulation (IVES) technique, involving low-oxygen gas mixture preconditioning using in vitro fertilization gas (IVFG) and direct current electrical stimulation (ES20), to enhance the anti-inflammatory properties of sEVs from canine adipose-derived MSCs (cAD-MSCs). Initial steps involved isolation and comprehensive characterization of cAD-MSCs, including morphology, gene expression, and differentiation potentials, alongside validation of the electrical stimulation protocol. IVFG, ES20, and IVES were applied simultaneously with a control condition. Stimulated cAD-MSCs were evaluated for morphological changes, cell viability, and gene expressions. Conditioned media were collected and purified for sEV isolation on Day1, Day2, and Day3. To validate the efficacy of IVES for sEV production, various analyses were conducted, including microscopic examination, surface marker assessment, zeta-potential measurement, protein quantification, nanoparticle tracking analysis, and determination of anti-inflammatory activity.

RESULTS

We found that IVES demonstrated non-cytotoxicity and induced crucial genotypic changes associated with sEV production in cAD-MSCs. Interestingly, IVFG influenced cellular adaptation, while ES20 induced hypoxia activation. By merging these stimulations, IVES enhanced sEV stability and quality profiles. The cAD-MSC-derived sEVs exhibited anti-inflammatory activity in lipopolysaccharide-induced RAW264.7 macrophages, emphasizing their improved effectiveness without cytotoxicity or immunogenicity. These effects were consistent across day 3 collection, indicating the establishment of an effective protocol for sEV production.

CONCLUSIONS

This research established an innovative sequential stimulation method with positive impact on sEV characteristics including stability, quality, and anti-inflammatory activity. This study not only contributes to the enhancement of sEV production but also sheds light on their functional aspects for therapeutic interventions.

Effects of Magnesium-Doped Hydroxyapatite Nanoparticles on Bioink Formulation for Bone Tissue Engineering

Bioprinting of nanohydroxyapatite (nHA)-based bioinks has attracted considerable interest in bone tissue engineering. However, the role and relevance of the physicochemical properties of nHA incorporated in a bioink, particularly in terms of its printability and the biological behavior of bioprinted cells, remain largely unexplored. In this study, two bioinspired nHAs with different chemical compositions, crystallinity, and morphologies were synthesized and characterized: a more crystalline, needle-like Mg2+-doped nHA (N-HA) and a more amorphous, rounded Mg2+- and CO32--doped nHA (R-HA). To investigate the effects of the different compositions and morphologies of these nanoparticles on the bioprinting of human bone marrow stromal cells (hBMSCs), gelatin and gelatin methacryloyl (GelMA) were selected as the bioink backbone. The addition of 1% (w/w) of these bioceramic nanoparticles significantly improved the printability of GelMA in terms of extrudability, buildability, and filament spreading. The biological potential of the bioinks was evaluated by examining the hBMSC viability, metabolic activity, and osteogenic differentiation over 21 days. Both nHAs showed high cell viability, with N-HA showing a significant increase in metabolic activity under nonosteogenic conditions and R-HA showing a notable increase with osteogenic stimulation. These results suggest that the two nHAs interact differently with their environment, highlighting the importance of both the chemistry and morphology in bioink performance. In addition, osteogenic differentiation further highlighted how the physicochemical properties of nHAs influence osteogenic markers at both the RNA and protein levels. Clearly, tailoring the physicochemical properties of hydroxyapatite nanoparticles is critical to developing more biomimetic bioinks with great potential for advancing bone bioprinting applications.

Tissue Engineering 3D-Printed Scaffold Using Allograft/Alginate/Gelatin Hydrogels Coated With Platelet-Rich Fibrin or Adipose Stromal Vascular Fraction Induces Osteogenesis In Vitro

Incorporating autologous patient-derived products has become imperative to enhance the continually improving outcomes in bone tissue engineering. With this objective in mind, this study aimed to evaluate the osteogenic potential of 3D-printed allograft-alginate-gelatin scaffolds coated with stromal vascular fraction (SVF) and platelet-rich fibrin (PRF). The primary goal was to develop a tissue-engineered construct capable of facilitating efficient bone regeneration through the utilization of biomaterials with advantageous properties and patient-derived products. To achieve this goal, 3D-printed gelatin, allograft, and alginate scaffolds were utilized, along with stem cells derived from the buccal fat pad and human-derived components (PRF, SVF). Cells were seeded onto scaffolds, both with and without SVF/PRF, and subjected to comprehensive assessments including adhesion, proliferation, differentiation (gene expression and protein secretion levels), penetration, and gene expression analysis over 14 days. The data was reported as mean ± standard deviation (SD). Two-way or one-way analysis of variance (ANOVA) was performed, followed by a Tukey post hoc test for multiple comparisons. Statistical significance was determined as a p value below 0.05. The scaffolds demonstrated structural integrity, and the addition of PRF coatings significantly enhanced cellular adhesion, proliferation, and differentiation compared to other groups. Gene expression analysis showed increased expression of osteogenic and angiogenic markers in the PRF-coated scaffolds. These findings highlight the promising role of PRF-coated scaffolds in promoting osteogenesis and facilitating bone tissue regeneration. This study emphasizes the development of patient-specific tissue-engineered constructs as a valuable approach for effective bone regeneration.

Alterations in the transcriptome and microRNAs of adipose-derived mesenchymal stem cells from different sites in rats during aging

Aging is an intricate and gradual process characterized by tissue and cellular dysfunction. Adipose-derived mesenchymal stem cells (ADMSCs) experience a functional decline as part of systemic aging. However, the alterations in ADMSCs across various anatomical sites throughout an individual's lifespan remain unclear. To shed light on these changes, we collected white adipose tissue and brown adipose tissue samples from the epididymis, perirenal, inguinal, and scapular regions of young, adult, and aged rats and subsequently isolated ADMSCs for RNA sequencing. As aging progressed, we observed a reduction in the number of ADMSCs at all anatomical sites. Marker genes of ADMSCs from different sites were identified. Aging triggered notable activation of inflammatory and immune responses while diminishing the ADMSC differentiation capacity and ability to maintain a normal tissue morphology. Furthermore, miR-195-5p and miR-497-3p, which promoted cell senescence and apoptosis while inhibiting proliferation and differentiation, were positively correlated with aging. These findings increase our understanding of ADMSC senescence and underscore the unique physiological changes and functions of ADMSCs across different anatomical sites during aging.NEW & NOTEWORTHY Dynamic changes in mRNAs and miRNAs of ADMSCs during aging are shown. As aging progressed, we observed a reduction in the number of ADMSCs at all anatomical sites. Aging leads to the activation of inflammatory and cellular dysfunction. miR-195-5p and miR-497-3p are positively correlated with aging, which promoted cell senescence and apoptosis while inhibiting proliferation and differentiation. ADMSCs associated with different anatomical sites have site-specific markers.

Impact of Porosity and Stiffness of 3D Printed Polycaprolactone Scaffolds on Osteogenic Differentiation of Human Mesenchymal Stromal Cells and Activation of Dendritic Cells

Despite the potential of extrusion-based printing of thermoplastic polymers in bone tissue engineering, the inherent nonporous stiff nature of the printed filaments may elicit immune responses that influence bone regeneration. In this study, bone scaffolds made of polycaprolactone (PCL) filaments with different internal microporosity and stiffness was 3D-printed. It was achieved by combining three fabrication techniques, salt leaching and 3D printing at either low or high temperatures (LT/HT) with or without nonsolvent induced phase separation (NIPS). Printing PCL at HT resulted in stiff scaffolds (modulus of elasticity (E): 403 ± 19 MPa and strain: 6.6 ± 0.1%), while NIPS-based printing at LT produced less stiff and highly flexible scaffolds (E: 53 ± 10 MPa and strain: 435 ± 105%). Moreover, the introduction of porosity by salt leaching in the printed filaments significantly changed the mechanical properties and degradation rate of the scaffolds. Furthermore, this study aimed to show how these variations influence proliferation and osteogenic differentiation of human bone marrow-derived mesenchymal stromal cells (hBMSC) and the maturation and activation of human monocyte-derived dendritic cells (Mo-DC). The cytocompatibility of the printed scaffolds was confirmed by live-dead imaging, metabolic activity measurement, and the continuous proliferation of hBMSC over 14 days. While all scaffolds facilitated the expression of osteogenic markers (RUNX2 and Collagen I) from hBMSC as detected through immunofluorescence staining, the variation in porosity and stiffness notably influenced the early and late mineralization. Furthermore, the flexible LT scaffolds, with porosity induced by NIPS and salt leaching, stimulated Mo-DC to adopt a pro-inflammatory phenotype marked by a significant increase in the expression of IL1B and TNF genes, alongside decreased expression of anti-inflammatory markers, IL10 and TGF1B. Altogether, the results of the current study demonstrate the importance of tailoring porosity and stiffness of PCL scaffolds to direct their biological performance toward a more immune-mediated bone healing process.

Rabbit visceral adipose stromal cell reveals phenotype and genotype characteristics of adult mesenchymal stem cell

Background

As an excellent model for many animal and human diseases, rabbits are the third-most used mammal model after mice and rats. A plethora of studies on the exploration of rabbit mesenchymal stem cells still face discrepancies, especially in the standardization of phenotype and genotype characteristics to support reproducibility in both biomedical and translational research.

Aim

This study is aimed to evaluate the characterization and differentiation potential of visceral rabbit adipose-derived mesenchymal stem cells (Rab-ADMSC).

Methods

Visceral adipose tissue was obtained from three healthy male White New Zealand rabbits. Cells were further processed and cultivated aseptically. Phenotype and genotype assessments, including morphological observation, proliferation capacity, population doubling time, stemness- and senescence-related genes determination, a set panel of mesenchymal stem/stromal cell (MSC) surface markers evaluation, and multilineage differentiation, were performed in this study.

Results

Visceral Rab-ADMSC exhibited fibroblast-like shape morphology and had a plastic adherent ability, expressed stemness- (NANOG, SOX2) and senescence-related (TP53, CDKN1A) markers. Visceral Rab-ADMSC performs high expression of CD9, moderate expression of CD44 and CD49f, dimly expression of CD105, CD90, and CD73, and negative expression of CD13 and CD133 as well as CD45 as a hematopoietic stem cell marker. Despite these discrepancies, visceral Rab-ADMSC maintained its ability to differentiate into osteocytes, adipocytes, and chondrocytes.

Conclusion

To recapitulate, visceral Rab-ADMSC reveals the phenotype and genotype characteristics of adult mesenchymal stem cells. The study emphasizes how variations in tissue sources, culture conditions, and techniques can affect the reproducibility and validity of MSC obtained from different specific anatomical depots and species. Thus, the utilization of rabbit MSC as an animal model in biomedical and translational studies should be done with full caution to avoid data misinterpretation.

An In Vivo Assessment of Different Mesenchymal Stromal Cell Tissue Types and Their Differentiation State on a Shape Memory Polymer Scaffold for Bone Regeneration

A combined biomaterial and cell-based solution to heal critical size bone defects in the craniomaxillofacial area is a promising alternative therapeutic option to improve upon autografting, the current gold standard. A shape memory polymer (SMP) scaffold, composed of biodegradable poly(ε-caprolactone) and coated with bioactive polydopamine, was evaluated with mesenchymal stromal cells (MSCs) derived from adipose (ADSC), bone marrow (BMSC), or umbilical cord (UCSC) tissue in their undifferentiated state or pre-differentiated toward osteoblasts for bone healing in a rat calvarial defect model. Pre-differentiating ADSCs and UCSCs resulted in higher new bone volume fraction (15.69% ± 1.64%) compared to empty (i.e., untreated) defects and scaffold-only (i.e., unseeded) groups (4.41% ± 1.11%). Notably, only differentiated UCSCs exhibited a significant increase in new bone volume, surpassing both undifferentiated UCSCs and unseeded scaffolds. Further, differentiated ADSCs and UCSCs had significantly higher trabecular numbers than their undifferentiated counterparts, unseeded scaffolds, and untreated defects. Although the mineral density regenerated within the unseeded scaffold surpassed that achieved with cell seeding, the connectivity of this bone was diminished, as the regenerated tissue confined itself to the spherical morphology of the scaffold pores. The SMP scaffold alone, with undifferentiated BMSCs, with undifferentiated and differentiated ADSCs, and differentiated UCSCs (29.72 ± 1.49 N) demonstrated significant osseointegration compared to empty defects (14.34 ± 2.21 N) after 12 weeks of healing when assessed by mechanical push-out testing. Based on these results and tissue availability to obtain the cells, pre-differentiated ADSCs and UCSCs emerge as particularly promising candidates when paired with the SMP scaffold for repairing critical size bone defects in the craniofacial skeleton.

An Acellular, Self-Healed Trilayer Cryogel for Osteochondral Regeneration in Rabbits

Osteochondral regeneration remains formidable challenges despite significant advances in microsurgery. Herein, an acellular trilayer cryogel (TC) with injectability, tunable pore sizes (80-200 µm), and appropriate compressive modulus (10.8 kPa) is manufactured from self-healable hydrogel under different gelling times through Schiff reaction between chitosan and difunctionalized polyurethane (DFPU). Bioactive molecules (Y27632 and dexamethasone) are respectively loaded in the top and bottom layers to form the Y27632/dexamethasone-loaded trilayer cryogel (Y/DEX-TC). Mesenchymal stem cells (MSCs) seeded in Y/DEX-TC proliferated ≈350% in vitro and underwent chondrogenesis or osteogenesis in response to the respective release of Y or DEX in 14 days. Acupuncture is administered to animals in an attempt to modulate the innate regulatory system and mobilize endogenous MSCs for osteochondral defect regeneration. In vivo rabbit experiments using Y/DEX-TC combined with acupuncture successfully regulate SDF-1 and TGF-β1 levels, which possibly cause MSC migration toward Y/DEX-TC. The synergistic effect of cryogel and acupuncture on immunomodulation is verified with a ≈7.3-fold enhancement of the M2-/M1-macrophage population ratio by treatment of Y/DEX-TC combining acupuncture, significantly greater than ≈1.5-fold increase by acupuncture or ≈2.2-fold increase by Y/DEX-TC alone. This novel strategy using acellular drug-loaded cryogel and accessible acupuncture shows promise in treating osteochondral defects of joint damage.

FKBP5 Regulates the Osteogenesis of Human Adipose-derived Mesenchymal Stem Cells

OBJECTIVE

Human adipose-derived stem cells (ASCs) have shown considerable potential for tissue regeneration. FK506 binding protein (FKBP) 5 is a cochaperone of several proteins. The purpose of this work was to explore the function of FKBP5 in ASC osteogenesis.

METHODS

Lentivirus infection was used to overexpress or knock down FKBP5 in ASCs. To inhibit FKBP5, SAFit2, a specific inhibitor of FKBP5, was used. Next, the osteogenic capacity of ASCs was evaluated via alkaline phosphatase (ALP) staining, and extracellular calcium precipitation was detected via Alizarin red S staining. The binding proteins of FKBP5 were assessed via proteomics and validated via coimmunoprecipitation experiments.

RESULTS

Following osteogenic induction, FKBP5 expression increased at both the mRNA and protein levels. Interestingly, FKBP5 upregulation by lentivirus infection increased the ability of ASCs to differentiate into osteoblasts, as revealed by ALP staining, while ALP activity also increased. Moreover, increased extracellular calcium precipitation confirmed that FKBP5 overexpression promoted ASC osteogenesis into osteocytes. On the other hand, FKBP5 knockdown or functional suppression with SAFit2 decreased this process. Furthermore, the proteomics and coimmunoprecipitation data demonstrated that FKBP5 bound to a variety of proteins in ASCs. These proteins serve as the molecular chaperone base upon which the osteogenesis-regulating activity of FKBP5 rests.

CONCLUSION

Our study revealed that FKBP5 enhances the osteogenesis of ASCs, providing a feasible method for clinical bone tissue engineering applications.

Novel osteogenic peptide from bovine bone collagen hydrolysate: Targeted screening, molecular mechanism, and stability analysis

This study aimed to screen for a novel osteogenic peptide based on the calcium-sensing receptor (CaSR) and explore its molecular mechanism and gastrointestinal stability. In this study, a novel osteogenic peptide (Phe-Ser-Gly-Leu, FSGL) derived from bovine bone collagen hydrolysate was successfully screened by molecular docking and synthesised by solid phase peptide synthesis for further analysis. Cell experiments showed that FSGL significantly enhanced the osteogenic activity of MC3T3-E1 cells by acting on CaSR, including proliferation (152.53%), differentiation, and mineralization. Molecular docking and molecular dynamics further demonstrated that FSGL was a potential allosteric activator of CaSR, that turned on the activation switch of CaSR by closing the Venus flytrap (VFT) domain and driving the two protein chains in the VFT domain to easily form dimers. In addition, 96.03% of the novel osteogenic peptide FSGL was stable during gastrointestinal digestion. Therefore, FSGL showed substantial potential for enhancing the osteogenic activity of osteoblasts. This study provided new insights for the application of CaSR in the targeted screening of osteogenic peptides to improve bone health.

Influence of mesenchymal stem cells from different origins on the therapeutic effectiveness of systemic lupus erythematosus

Systemic Lupus Erythematosus (SLE) is a chronic autoimmune inflammatory disorder characterized by alterations in the balance between inflammatory and regulatory cytokines. Mesenchymal stem cells (MSCs), which are non-hematopoietic stem cells with multipotent differentiation potential, due to their immunomodulatory, tissue repair, low immunogenicity, and chemotactic properties, have garnered increasing interest in SLE treatment. Studies increasingly reveal the heterogeneous nature of MSC populations. With sources including dental pulp, adipose tissue, bone marrow, and umbilical cord, the therapeutic effects of MSCs on SLE vary depending on their origin. This review consolidates clinical research on MSCs from different sources in treating SLE and analyzes the possible causes underlying these variable outcomes. Additionally, it elucidates five potential factors impacting the outcomes of MSC therapy in SLE: the influence of the microenvironment on MSCs, the complexity and paradoxical aspects of MSC mechanisms in SLE treatment, the heterogeneity of MSCs, the in vivo differentiation potential and post-transplant survival rates of MSCs, and disparities in MSC preparation conditions.

Angelica sinensis polysaccharide facilitates chondrogenic differentiation of adipose-derived stem cells via MDK-PI3K/AKT signaling cascade

OBJECT

Adipose-derived mesenchymal stem cells (ADSCs) have received significant attention in the field of cartilage tissue repair. Angelica sinensis polysaccharide (ASP) can enhance both the proliferation and differentiation of mesenchymal stem cells. Therefore, we intend to explore the effect of ASP on chondrogenic differentiation of ADSCs in vitro, and elucidate the underlying mechanisms.

METHOD

ADSCs were treated with different concentrations of ASP to determine the optimal concentration. The chondrogenic differentiation of ADSCs was evaluated using Alcian blue staining, qRT-PCR, western blot, and IF staining. Transcriptome sequencing was performed to identify the expression profiles of ADSCs before and after ASP treatment, followed by bioinformatic analyses including differential expression analysis, enrichment analysis, and construction of PPI networks to identify differentially expressed genes (DEGs) associated with ASP and chondrogenic differentiation.

RESULT

Surface markers of isolated rat-derived ADSCs were identified by CD44+CD90+CD45-CD106-, and exhibited the capacity for lipogenic, osteogenic, and chondrogenic differentiation. With increasing concentration of ASP treatment, there was an upregulation in the activity and acidic mucosubstance of ADSCs. The levels of Aggrecan, COL2A1, and Sox9 showed an increase in ADSCs after 28 days of 80 µg/ml ASP treatment. Transcriptome sequencing revealed that ASP-associated DEGs regulate extracellular matrix synthesis, immune response, inflammatory response, and cell cycle, and are involved in the NF-κB, AGE-RAGE, and calcium pathways. Moreover, Edn1, Frzb, Mdk, Nog, and Sulf1 are hub genes in DEGs. Notably, ASP upregulated MDK levels in ADSCs, while knockdown of MDK mitigated ASP-induced elevations in acidic mucosubstance, chondrogenic differentiation-related markers (Aggrecan, COL2A1, and Sox9), and the activity of the PI3K/AKT pathway.

CONCLUSION

ASP enhances the proliferation and chondrogenic differentiation of ADSCs by activating the MDK-mediated PI3K/AKT pathway.

Donor Sex and Passage Conditions Influence MSC Osteogenic Response in Mineralized Collagen Scaffolds

Contemporary tissue engineering efforts often seek to use mesenchymal stem cells (MSCs) due to their multi-potent potential and ability to generate a pro-regenerative secretome. While many have reported the influence of matrix environment on MSC osteogenic response, few have investigated the effects of donor and sex. Here, a well-defined mineralized collagen scaffold is used to study the influence of passage number and donor-reported sex on MSC proliferation and osteogenic potential. A library of bone marrow and adipose tissue-derived stem cells from eight donors to examine donor viability in osteogenic capacity in mineralized collagen scaffolds is obtained. MSCs displayed reduced proliferative capacity as a function of passage duration. Further, MSCs showed significant sex-associated variability in osteogenic capacity. Notably, MSCs from male donors displayed significantly higher cell proliferation while MSCs from female donors displayed significantly higher osteogenic response via increased alkaline phosphate activity, osteoprotegerin release, and mineral formation in vitro. The study highlights the essentiality of including donor-reported sex as an experimental variable and reporting culture expansion in future studies of biomaterial regenerative potential.

Photo-Clickable Triazine-Trione Thermosets as Promising 3D Scaffolds for Tissue Engineering Applications

There is an overwhelming demand for new scaffolding materials for tissue engineering (TE) purposes. Polymeric scaffolds have been explored as TE materials; however, their high glass transition state (Tg) limits their applicability. In this study, a novel materials platform for fabricating TE scaffolds is proposed based on solvent-free two-component heterocyclic triazine-trione (TATO) formulations, which cure at room temperature via thiol-ene/yne photochemistry. Three ester-containing thermosets, TATO-1, TATO-2, and TATO-3, are used for the fabrication of TE scaffolds including rigid discs, elastic films, microporous sponges, and 3D printed objects. After 14 days' incubation the materials covered a wide range of properties, from the soft TATO-2 having a compression modulus of 19.3 MPa and a Tg of 30.4 °C to the hard TATO-3 having a compression modulus of 411 MPa and a Tg of 62.5 °C. All materials exhibit micro- and nano-surface morphologies suited for bone tissue engineering, and in vitro studies found them all to be cytocompatible, supporting fast cell proliferation while minimizing cell apoptosis and necrosis. Moreover, bone marrow-derived mesenchymal stem cells on the surface of the materials are successfully differentiated into osteoblasts, adipocytes, and neuronal cells, underlining the broad potential for the biofabrication of TATO materials for TE clinical applications.

How to enhance MSCs therapeutic properties? An insight on potentiation methods

Mesenchymal stem/stromal cells (MSCs) have emerged as a promising tool in the field of regenerative medicine due to their unique therapeutic properties as they can differentiate into multiple cell types and exert paracrine effects. However, despite encouraging results obtained in preclinical studies, clinical trials have not achieved the same levels of efficacy. To improve the therapeutic properties of MSCs, several strategies have been explored. Therefore, in this review, the therapeutic properties of MSCs will be analyzed, and an update and overview of the most prominent approaches used to enhance their therapeutic capabilities will be provided. These approaches include using drugs, molecules, strategies based on biomaterials, and modification parameters in culture. The strategy described shows several common factors among those affected by these strategies that lead to an enhancement of the MSCs therapeutic properties such as the activation of the PI3K/AKT pathway and the increased expression of Heat Shock Proteins and Hypoxia-Inducible Factor. The combined effect of these elements shift MSCs towards a glycolytic state, suggesting this shift is essential for their enhancement.

Hyaluronic acid methacryloyl/chitosan methacryloyl/3-methacrylamidophenylboronic acid multifunctional hydrogel loading exosome for diabetic wound healing

The management of diabetic wounds presents a formidable challenge in clinical settings due to elevated glucose levels, drug-resistant bacterial infections, and a deficiency of bioactive molecules in the microenvironment. To address this challenge, a glucose-responsive Hyaluronic acid Methacryloyl (HAMA)-Chitosan Methacryloyl (CSMA)-3-Methacrylamidophenylboronic acid (MPBA) loading Exosome (H-C-M@Exo) multifunctional hydrogel has been developed to enhance diabetic wound healing in this study. The H-C-M@Exo hydrogel exhibits remarkable features, including high hydrophilicity, excellent pressure resistance, antibacterial properties, and good biocompatibility. It uniquely possesses the ability to sustain the release of exosomes in response to glucose fluctuations. The H-C-M@Exo hydrogel can effectively reduce inflammation, significantly promote rapid re-epithelization, facilitate favorable collagen deposition, and stimulate abundant angiogenesis at the wound sites. Furthermore, the hydrogel induces localized regulation of M2 macrophage polarization, synergistically promoting diabetic angiogenesis and wound healing. These findings suggest H-C-M@Exo hydrogel is a promising biomaterial for the treatment of chronic diabetic wounds.

Electrical signature of heterogeneous human mesenchymal stem cells

Human mesenchymal stem cells (hMSCs) have gained traction in transplantation therapy due to their immunomodulatory, paracrine, immune-evasive, and multipotent differentiation potential. The inherent heterogeneity of hMSCs poses a challenge for therapeutic treatments and necessitates the identification of robust biomarkers to ensure reproducibility in both in vivo and in vitro experiments. In this study, we utilized dielectrophoresis (DEP), a label-free electrokinetic phenomenon, to investigate the heterogeneity of hMSCs derived from bone marrow (BM) and adipose tissue (AD). The electrical properties of BM-hMSCs were compared to homogeneous mouse fibroblasts (NIH-3T3), human fibroblasts (WS1), and human embryonic kidney cells (HEK-293). The DEP profile of BM-hMSCs differed most from HEK-293 cells. We compared the DEP profiles of BM-hMSCs and AD-hMSCs and found that they have similar membrane capacitances, differing cytoplasm conductivity, and transient slopes. Inducing both populations to differentiate into adipocyte and osteoblast cells revealed that they behave differently in response to differentiation-inducing cytokines. Histology and reverse transcription-quantitative polymerase chain reaction (RT-qPCR) analyses of the differentiation-related genes revealed differences in heterogeneity between BM-hMSCs and AD-hMSCs. The differentiation profiles correlate well with the DEP profiles developed and indicate differences in the heterogeneity of BM-hMSCs and AD-hMSCs. Our results demonstrate that using DEP, membrane capacitance, cytoplasm conductivity, and transient slope can uniquely characterize the inherent heterogeneity of hMSCs to guide robust and reproducible stem cell transplantation therapies.

The role of cells and their derivatives in otorhinolaryngologic diseases treatment

Otolaryngology is an important specialty in the field of surgery that deals with the diagnosis and treatment of the ear, nose, throat, trachea, as well as related anatomical structures. Various otolaryngological disorders are difficult to treat using established pharmacological and surgical approaches. The advent of molecular and cellular therapies led to further progress in this respect. This article reviews the therapeutic strategies of using stem cells, immune cells, and chondrocytes in otorhinolaryngology. As the most widely recognized cell derivatives, exosomes were also systematically reviewed for their therapeutic potential in head and neck cancer, otitis media, and allergic rhinitis. Finally, we summarize the limitations of stem cells, chondrocytes, and exosomes, as well as possible solutions, and provide an outlook on the future direction of cell- and derivative-based therapies in otorhinolaryngology, to offer a theoretical foundation for the clinical translation of this therapeutic modality.

Mesenchymal stem cells derived from human adipose tissue exhibit significantly higher chondrogenic differentiation potential compared to those from rats

BACKGROUND

Osteoarthritis is a prevalent joint disease affecting both humans and animals. It is characterized by articular cartilage degeneration and joint surface eburnation. Currently, no effective pharmacological treatment is available to restore the original function and structure of defective cartilage.

OBJECTIVE

This study explores the potential of stem cell-based therapy in treating joint diseases involving cartilage degeneration, offering a promising avenue for future research and treatment. The primary aim was to compare the characteristics and, more importantly, the chondrogenic differentiation potential of human and rat adipose-derived mesenchymal stem cells (AD-MSCs).

METHODS

Rat adipose tissue was collected from Sprague Dawley rats, while human adipose tissue was obtained in the form of lipoaspirate. The mesenchymal stem cells (MSCs) were then harvested using collagenase enzyme and subcultured. We meticulously evaluated and compared the cell morphology, percentage of cell viability, population doubling time, metabolic proliferation, and chondrogenic differentiation potential of MSCs harvested from both sources. Chondrogenic differentiation was induced at passage 3 using the 3D pellet culture method and assessed through histological and molecular analysis.

RESULTS

The findings revealed that human and rat AD-MSCs were phenotypically identical, and an insignificant difference was found in cell morphology, percentage of cell viability, metabolic proliferation, and population doubling time. However, the chondrogenic differentiation potential of human AD-MSCs was evaluated as significantly higher than that of rat AD-MSCs.

CONCLUSION

The current study suggests that research regarding chondrogenic differentiation of rat AD-MSCs can be effectively translated to humans. This discovery is a significant contribution to the field of regenerative medicine and has the potential to advance our understanding of stem cell-based therapy for joint diseases.

Genetic deletion of ITIH5 leads to increased development of adipose tissue in mice

BACKGROUND

Adipocytokines play a pivotal role in maintaining adipose tissue homeostasis by regulating cellular metabolism, proliferation, differentiation, and secretory activity. These soluble factors are relevant components for healthy adipose tissue, while their deficiency is closely associated with the development of obesity and related metabolic diseases, e.g., chronic inflammation. In human adipose tissue, inter-α-trypsin inhibitor heavy chain 5 (ITIH5) is expressed in proportion to the development of adipose tissue, i.e., the individual's BMI. Thus, ITIH5 has been proposed to be an inert marker of human obesity. However, when applied to adipose stem cells in vitro, recombinant (r)ITIH5 protein inhibited proliferation and adipogenesis, suggesting that ITIH5 negatively affects the development of fat mass. We now tested the role of ITIH5 in vivo and compared ITIH5+/+ wildtype with ITIH5-/- knockout mice.

RESULTS

Genetic deletion of ITIH5 significantly increased adipose tissue mass relative to animal bodyweight (p < 0.05). Next, we characterized adipose stem cells (ASCs) from both genotypes in vitro. ITIH5-/- cells exhibited increased proliferation and adipogenic differentiation (p < 0.001), which could explain the increase in adipose tissue in vivo. Furthermore, ASCs from ITIH5-/- animals were more responsive to stimulation with inflammatory mediators, i.e., these cells released greater amounts of IL-6 and MCP-1 (p < 0.001). Importantly, the application of the rITIH5 protein reversed the observed knockout effects in ASCs.

CONCLUSIONS

Our data suggest that ITIH5 potently regulates adipose tissue development and homeostasis by modulating ASC biology in mice. In addition, the effect of the rITIH5 protein underscores its potential as a therapeutic agent to correct the adipose tissue dysregulation often associated with obesity and metabolic disorders.

Translational potential of mesenchymal stem cells in regenerative therapies for human diseases: challenges and opportunities

Advances in stem cell technology offer new possibilities for patients with untreated diseases and disorders. Stem cell-based therapy, which includes multipotent mesenchymal stem cells (MSCs), has recently become important in regenerative therapies. MSCs are multipotent progenitor cells that possess the ability to undergo in vitro self-renewal and differentiate into various mesenchymal lineages. MSCs have demonstrated promise in several areas, such as tissue regeneration, immunological modulation, anti-inflammatory qualities, and wound healing. Additionally, the development of specific guidelines and quality control methods that ultimately result in the therapeutic application of MSCs has been made easier by recent advancements in the study of MSC biology. This review discusses the latest clinical uses of MSCs obtained from the umbilical cord (UC), bone marrow (BM), or adipose tissue (AT) in treating various human diseases such as pulmonary dysfunctions, neurological disorders, endocrine/metabolic diseases, skin burns, cardiovascular conditions, and reproductive disorders. Additionally, this review offers comprehensive information regarding the clinical application of targeted therapies utilizing MSCs. It also presents and examines the concept of MSC tissue origin and its potential impact on the function of MSCs in downstream applications. The ultimate aim of this research is to facilitate translational research into clinical applications in regenerative therapies.

Lamc1 promotes osteogenic differentiation and inhibits adipogenic differentiation of bone marrow-derived mesenchymal stem cells

Bone marrow-derived mesenchymal stem cells (BMSCs) exhibit multi-lineage differentiation potential and robust proliferative capacity. The late stage of differentiation signifies the functional maturation and characterization of specific cell lineages, which is crucial for studying lineage-specific differentiation mechanisms. However, the molecular processes governing late-stage BMSC differentiation remain poorly understood. This study aimed to elucidate the key biological processes involved in late-stage BMSC differentiation. Publicly available transcriptomic data from human BMSCs were analyzed after approximately 14 days of osteogenic, adipogenic, and chondrogenic differentiation. Thirty-one differentially expressed genes (DEGs) associated with differentiation were identified. Pathway enrichment analysis indicated that the DEGs were involved in extracellular matrix (ECM)-receptor interactions, focal adhesion, and glycolipid biosynthesis, a ganglion series process. Subsequently, the target genes were validated using publicly available single-cell RNA-seq data from mouse BMSCs. Lamc1 exhibited predominant distribution in adipocytes and osteoblasts, primarily during the G2/M phase. Tln2 and Hexb were expressed in chondroblasts, osteoblasts, and adipocytes, while St3gal5 was abundantly distributed in stem cells. Cell communication analysis identified two receptors that interact with LAMCI. q-PCR results confirmed the upregulation of Lamc1, Tln2, Hexb, and St3gal5 during osteogenic differentiation and their downregulation during adipogenic differentiation. Knockdown of Lamc1 inhibited adipogenic and osteogenic differentiation. In conclusion, this study identified four genes, Lamc1, Tln2, Hexb, and St3gal5, that may play important roles in the late-stage differentiation of BMSCs. It elucidated their interactions and the pathways they influence, providing a foundation for further research on BMSC differentiation.

The Myofibroblast Fate of Therapeutic Mesenchymal Stromal Cells: Regeneration, Repair, or Despair?

Mesenchymal stromal cells (MSCs) can be isolated from various tissues of healthy or patient donors to be retransplanted in cell therapies. Because the number of MSCs obtained from biopsies is typically too low for direct clinical application, MSC expansion in cell culture is required. However, ex vivo amplification often reduces the desired MSC regenerative potential and enhances undesired traits, such as activation into fibrogenic myofibroblasts. Transiently activated myofibroblasts restore tissue integrity after organ injury by producing and contracting extracellular matrix into scar tissue. In contrast, persistent myofibroblasts cause excessive scarring-called fibrosis-that destroys organ function. In this review, we focus on the relevance and molecular mechanisms of myofibroblast activation upon contact with stiff cell culture plastic or recipient scar tissue, such as hypertrophic scars of large skin burns. We discuss cell mechanoperception mechanisms such as integrins and stretch-activated channels, mechanotransduction through the contractile actin cytoskeleton, and conversion of mechanical signals into transcriptional programs via mechanosensitive co-transcription factors, such as YAP, TAZ, and MRTF. We further elaborate how prolonged mechanical stress can create persistent myofibroblast memory by direct mechanotransduction to the nucleus that can evoke lasting epigenetic modifications at the DNA level, such as histone methylation and acetylation. We conclude by projecting how cell culture mechanics can be modulated to generate MSCs, which epigenetically protected against myofibroblast activation and transport desired regeneration potential to the recipient tissue environment in clinical therapies.

Extracellular Vesicles from Adipose Tissue-Derived Stromal Cells Stimulate Angiogenesis in a Scaffold-Dependent Fashion

BACKGROUND

The extracellular vesicles (EVs) secreted by adipose tissue-derived stromal cells (ASC) are microenvironment modulators in tissue regeneration by releasing their molecular cargo, including miRNAs. However, the influence of ASC-derived extracellular vesicles (ASC-EVs) on endothelial cells (ECs) and vascularisation is poorly understood. The present study aimed to determine the pro-angiogenic effects of ASC-EVs and explore their miRNA profile.

METHODS

EVs were isolated from normoxic and hypoxic cultured ASC conditioned culture medium. The miRNA expression profile was determined by miRseq, and EV markers were determined by Western blot and immunofluorescence staining. The uptake dynamics of fluorescently labelled EVs were monitored for 24 h. ASC-EVs' pro-angiogenic effect was assessed by sprouting ex vivo rat aorta rings in left ventricular-decellularized extracellular matrix (LV dECM) hydrogel or basement membrane hydrogel (Geltrex®).

RESULTS

ASC-EVs augmented vascular network formation by aorta rings. The vascular network topology and stability were influenced in a hydrogel scaffold-dependent fashion. The ASC-EVs were enriched for several miRNA families/clusters, including Let-7 and miR-23/27/24. The miRNA-1290 was the highest enriched non-clustered miRNA, accounting for almost 20% of all reads in hypoxia EVs.

CONCLUSION

Our study revealed that ASC-EVs augment in vitro and ex vivo vascularisation, likely due to the enriched pro-angiogenic miRNAs in EVs, particularly miR-1290. Our results show promise for regenerative and revascularisation therapies based on ASC-EV-loaded ECM hydrogels.

Mesenchymal Stromal Cells for the Enhancement of Surgical Flexor Tendon Repair in Animal Models: A Systematic Review and Meta-Analysis

Flexor tendon lacerations are primarily treated by surgical repair. Limited intrinsic healing ability means the repair site can remain weak. Furthermore, adhesion formation may reduce range of motion post-operatively. Mesenchymal stromal cells (MSCs) have been trialled for repair and regeneration of multiple musculoskeletal structures. Our goal was to determine the efficacy of MSCs in enhancing the biomechanical properties of surgically repaired flexor tendons. A PRISMA systematic review was conducted using four databases (PubMed, Ovid, Web of Science, and CINAHL) to identify studies using MSCs to augment surgical repair of flexor tendon injuries in animals compared to surgical repair alone. Nine studies were included, which investigated either bone marrow- or adipose-derived MSCs. Results of biomechanical testing were extracted and meta-analyses were performed regarding the maximum load, friction and properties relating to viscoelastic behaviour. There was no significant difference in maximum load at final follow-up. However, friction, a surrogate measure of adhesions, was significantly reduced following the application of MSCs (p = 0.04). Other properties showed variable results and dissipation of the therapeutic benefits of MSCs over time. In conclusion, MSCs reduce adhesion formation following tendon injury. This may result from their immunomodulatory function, dampening the inflammatory response. However, this may come at the cost of favourable healing which will restore the tendon's viscoelastic properties. The short duration of some improvements may reflect MSCs' limited survival or poor retention. Further investigation is needed to clarify the effect of MSC therapy and optimise its duration of action.

Role of Adipose-Derived Mesenchymal Stem Cells in Bone Regeneration

Bone regeneration involves multiple factors such as tissue interactions, an inflammatory response, and vessel formation. In the event of diseases, old age, lifestyle, or trauma, bone regeneration can be impaired which could result in a prolonged healing duration or requiring an external intervention for repair. Currently, bone grafts hold the golden standard for bone regeneration. However, several limitations hinder its clinical applications, e.g., donor site morbidity, an insufficient tissue volume, and uncertain post-operative outcomes. Bone tissue engineering, involving stem cells seeded onto scaffolds, has thus been a promising treatment alternative for bone regeneration. Adipose-derived mesenchymal stem cells (AD-MSCs) are known to hold therapeutic value for the treatment of various clinical conditions and have displayed feasibility and significant effectiveness due to their ease of isolation, non-invasive, abundance in quantity, and osteogenic capacity. Notably, in vitro studies showed AD-MSCs holding a high proliferation capacity, multi-differentiation potential through the release of a variety of factors, and extracellular vesicles, allowing them to repair damaged tissues. In vivo and clinical studies showed AD-MSCs favoring better vascularization and the integration of the scaffolds, while the presence of scaffolds has enhanced the osteogenesis potential of AD-MSCs, thus yielding optimal bone formation outcomes. Effective bone regeneration requires the interplay of both AD-MSCs and scaffolds (material, pore size) to improve the osteogenic and vasculogenic capacity. This review presents the advances and applications of AD-MSCs for bone regeneration and bone tissue engineering, focusing on the in vitro, in vivo, and clinical studies involving AD-MSCs for bone tissue engineering.

Stem Cells and Acellular Preparations in Bone Regeneration/Fracture Healing: Current Therapies and Future Directions

Bone/fracture healing is a complex process with different steps and four basic tissue layers being affected: cortical bone, periosteum, fascial tissue surrounding the fracture, and bone marrow. Stem cells and their derivatives, including embryonic stem cells, induced pluripotent stem cells, mesenchymal stem cells, hematopoietic stem cells, skeletal stem cells, and multipotent stem cells, can function to artificially introduce highly regenerative cells into decrepit biological tissues and augment the healing process at the tissue level. Stem cells are molecularly and functionally indistinguishable from standard human tissues. The widespread appeal of stem cell therapy lies in its potential benefits as a therapeutic technology that, if harnessed, can be applied in clinical settings. This review aims to establish the molecular pathophysiology of bone healing and the current stem cell interventions that disrupt or augment the bone healing process and, finally, considers the future direction/therapeutic options related to stem cells and bone healing.

The Efficacy of Bone Marrow Stem Cell Therapy in Hip Osteoarthritis: A Scoping Review

Background

Hip osteoarthritis (HOA) is a prevalent degenerative joint disease with various treatment approaches. Biological agents, such as bone-marrow derived stem cells (BM-MSC) therapy, have recently been proposed as a treatment option in the management of HOA.

Purpose

We sought to further analyze the use of BM-MSC therapy by investigating the following questions. What is the standard preparation and practice? Does a dose response exist between stem cell therapy and clinical outcome? Does BM-MSC therapy alone produce effective clinical outcomes?

Methods

We conducted a scoping review using the Methodological Expectations of Cochrane Intervention Reviews Manual and the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines for scoping reviews. A comprehensive search of PubMed, Embase, Cochrane CENTRAL, Scopus, SPORTDiscus, Cumulative Index to Nursing and Allied Health Literature, and Web of Science Core Collection was performed in June 2023 of studies using exclusively BM-MSC injections for the treatment of HOA. Study characteristic, injection preparation and dosage, clinical outcome measures, and adverse effect data were extracted and interpreted by 3 reviewers.

Results

Seven studies with a total of 72 patients met the inclusion criteria. Clinical outcome following intra-articular injection of BM-MSCs was measured using the numerical pain scale, the Western Ontario and McMaster Universities Osteoarthritis Index, the visual analogue scale, and other scores, all of which showed reduction in pain and increase in functional ability across studies.

Conclusions

This scoping review found that the efficacy of BM-MSC therapy alone in the treatment of HOA appeared beneficial, improving clinical outcomes in each study. All 7 studies used "low-dose" injections with variable follow-up times; thus, a clear dose-response relationship cannot be drawn. Future studies using high doses and analyzing long-term effects of BM-MSC injections in HOA are needed.

Specific Features of the Functional Activity of Human Adipose Stromal Cells in the Structure of a Partial Skin-Equivalent

Mesenchymal adipose stromal cells (ASCs) are considered the most promising and accessible material for translational medicine. ASCs can be used independently or within the structure of scaffold-based constructs, as these not only ensure mechanical support, but can also optimize conditions for cell activity, as specific features of the scaffold structure have an impact on the vital activity of the cells. This manuscript presents a study of the secretion and accumulation that occur in a conditioned medium during the cultivation of human ASCs within the structure of such a partial skin-equivalent that is in contact with it. It is demonstrated that the ASCs retain their functional activity during cultivation both within this partial skin-equivalent structure and, separately, on plastic substrates: they proliferate and secrete various proteins that can then accumulate in the conditioned media. Our comparative study of changes in the conditioned media during cultivation of ASCs on plastic and within the partial skin-equivalent structure reveals the different dynamics of the release and accumulation of such secretory factors in the media under a variety of conditions of cell functioning. It is also demonstrated that the optimal markers for assessment of the ASCs' secretory functions in the studied partial skin-equivalent structure are the trophic factors VEGF-A, HGF, MCP, SDF-1α, IL-6 and IL-8. The results will help with the development of an algorithm for preclinical studies of this skin-equivalent in vitro and may be useful in studying various other complex constructs that include ASCs.

Correlation between Ca Release and Osteoconduction by 3D-Printed Hydroxyapatite-Based Templates

The application of hydroxyapatite (HA)-based templates is quite often seen in bone tissue engineering since that HA is an osteoconductive bioceramic material, which mimics the inorganic component of mineralized tissues. However, the reported osteoconductivity varies in vitro and in vivo, and the levels of calcium (Ca) release most favorable to osteoconduction have yet to be determined. In this study, HA-based templates were fabricated by melt-extrusion 3D-printing and characterized in order to determine a possible correlation between Ca release and osteoconduction. The HA-based templates were blended with poly(lactide-co-trimethylene carbonate) (PLATMC) at three different HA ratios: 10, 30, and 50%. The printability and physical properties of the HA templates were compared with those of pristine PLATMC. In vitro, osteoconductivity was assessed using seeded human bone marrow-derived mesenchymal stem cells. A mild rate of Ca release was observed for HA10 templates, which exhibited higher mineralized extracellular matrix (ECM) secretion than PLATMC at 14 and 21 days. In contrast, the high rate of Ca release exhibited by HA30 and HA50 templates was associated with reduced osteoconduction and impeded mineralized ECM secretion in vitro. Similar results were observed in vivo. In the calvarial defect model in rabbit, PLATMC and HA10 templates exhibited the highest amount of new bone formation, with obvious contact osteogenesis on their surfaces. In contrast, HA30 and HA50 exhibited distant osteogenesis and reduced amounts of new bone ingrowth. It is concluded that HA-based templates are osteoconductive only at low rates of Ca release.

Understanding molecular characteristics of extracellular vesicles derived from different types of mesenchymal stem cells for therapeutic translation

Mesenchymal stem cells (MSCs) have been studied for decades as candidates for cellular therapy, and their secretome, including secreted extracellular vesicles (EVs), has been identified to contribute significantly to regenerative and reparative functions. Emerging evidence has suggested that MSC-EVs alone, could be used as therapeutics that emulate the biological function of MSCs. However, just as with MSCs, MSC-EVs have been shown to vary in composition, depending on the tissue source of the MSCs as well as the protocols employed in culturing the MSCs and obtaining the EVs. Therefore, the importance of careful choice of cell sources and culture environments is receiving increasing attention. Many factors contribute to the therapeutic potential of MSC-EVs, including the source tissue, isolation technique, and culturing conditions. This review illustrates the molecular landscape of EVs derived from different types of MSC cells along with culture strategies. A thorough analysis of publicly available omic datasets was performed to advance the precision understanding of MSC-EVs with unique tissue source-dependent molecular characteristics. The tissue-specific protein and miRNA-driven Reactome ontology analysis was used to reveal distinct patterns of top Reactome ontology pathways across adipose, bone marrow, and umbilical MSC-EVs. Moreover, a meta-analysis assisted by an AI technique was used to analyze the published literature, providing insights into the therapeutic translation of MSC-EVs based on their source tissues.

Mesenchymal stromal cells derived from various tissues: Biological, clinical and cryopreservation aspects: Update from 2015 review

Mesenchymal stromal cells (MSCs) have become one of the most investigated and applied cells for cellular therapy and regenerative medicine. In this update of our review published in 2015, we show that studies continue to abound regarding the characterization of MSCs to distinguish them from other similar cell types, the discovery of new tissue sources of MSCs, and the confirmation of their properties and functions that render them suitable as a therapeutic. Because cryopreservation is widely recognized as the only technology that would enable the on-demand availability of MSCs, here we show that although the traditional method of cryopreserving cells by slow cooling in the presence of 10% dimethyl sulfoxide (Me2SO) continues to be used by many, several novel MSC cryopreservation approaches have emerged. As in our previous review, we conclude from these recent reports that viable and functional MSCs from diverse tissues can be recovered after cryopreservation using a variety of cryoprotectants, freezing protocols, storage temperatures, and periods of storage. We also show that for logistical reasons there are now more studies devoted to the cryopreservation of tissues from which MSCs are derived. A new topic included in this review covers the application in COVID-19 of MSCs arising from their immunomodulatory and antiviral properties. Due to the inherent heterogeneity in MSC populations from different sources there is still no standardized procedure for their isolation, identification, functional characterization, cryopreservation, and route of administration, and not likely to be a "one-size-fits-all" approach in their applications in cell-based therapy and regenerative medicine.

Recent advancements in cartilage tissue engineering innovation and translation

Articular cartilage was expected to be one of the first successfully engineered tissues, but today, cartilage repair products are few and they exhibit considerable limitations. For example, of the cell-based products that are available globally, only one is marketed for non-knee indications, none are indicated for severe osteoarthritis or rheumatoid arthritis, and only one is approved for marketing in the USA. However, advances in cartilage tissue engineering might now finally lead to the development of new cartilage repair products. To understand the potential in this field, it helps to consider the current landscape of tissue-engineered products for articular cartilage repair and particularly cell-based therapies. Advances relating to cell sources, bioactive stimuli and scaffold or scaffold-free approaches should now contribute to progress in therapeutic development. Engineering for an inflammatory environment is required because of the need for implants to withstand immune challenge within joints affected by osteoarthritis or rheumatoid arthritis. Bringing additional cartilage repair products to the market will require an understanding of the translational vector for their commercialization. Advances thus far can facilitate the future translation of engineered cartilage products to benefit the millions of patients who suffer from cartilage injuries and arthritides.

Comparison of different sources of mesenchymal stem cells: focus on inflammatory bowel disease

Inflammatory bowel disease (IBD) poses a significant challenge in modern medicine, with conventional treatments limited by efficacy and associated side effects, necessitating innovative therapeutic approaches. Mesenchymal stem cells (MSC) have emerged as promising candidates for IBD treatment due to their immunomodulatory properties and regenerative potential. This thesis aims to explore and compare various sources of MSC and evaluate their efficacy in treating IBD. This study comprehensively analyses MSC derived from multiple sources, including bone marrow, adipose tissue, umbilical cord, and other potential reservoirs. Core elements of this investigation include assessing differences in cell acquisition, immunomodulatory effects, and differentiation capabilities among these MSC sources, as well as comparing their clinical trial outcomes in IBD patients to their therapeutic efficacy in animal models. Through meticulous evaluation and comparative analysis, this thesis aims to elucidate disparities in the efficacy of different MSC sources for IBD treatment, thereby identifying the most promising therapeutic applications. The findings of this study are intended to advance our understanding of MSC biology and offer valuable insights for selecting the most effective MSC sources for personalized IBD therapy. Ultimately, this research endeavor will optimise therapeutic strategies for managing inflammatory bowel disease through the utilization of MSC.