Multipotent Cells Research Articles

The role of mitochondrial transfer in the suppression of CD8+ T cell responses by Mesenchymal stem cells

Background. CD8+ Cytotoxic T lymphocytes play a key role in the pathogenesis of autoimmune diseases and clinical conditions such as graft versus host disease and graft rejection. Mesenchymal Stromal Cells (MSCs) are multipotent cells with tissue repair and immunomodulatory capabilities. Since they are able to suppress multiple pathogenic immune responses, MSCs have been proposed as a cellular therapy for the treatment of immune-mediated diseases. However, the mechanisms underlying their immunosuppressive properties are not yet fully understood. MSCs have the remarkable ability to sense tissue injury and inflammation and respond by donating their own mitochondria to neighboring cells. Whether mitochondrial transfer has any role in the repression of CD8+ responses is unknown.Methods and results. We have utilized CD8+ T cells from Clone 4 TCR transgenic mice that differentiate into effector cells upon activation in vitro and in vivo to address this question. Allogeneic bone marrow derived MSCs, co-cultured with activated Clone 4 CD8+ T cells, decreased their expansion, the production of the effector cytokine IFNγ and their diabetogenic potential in vivo. Notably, we found that during this interaction leading to suppression, MSCs transferred mitochondria to CD8+ T cells as evidenced by FACS and confocal microscopy. Transfer of MSC mitochondria to Clone 4 CD8+ T cells also resulted in decreased expansion and production of IFNγ upon activation. These effects overlapped and were additive with those of prostaglandin E2 secreted by MSCs. Furthermore, preventing mitochondrial transfer in co-cultures diminished the ability of MSCs to inhibit IFNγ production. Finally, we demonstrated that both MSCs and MSC mitochondria downregulated T-bet and Eomes expression, key transcription factors for CTL differentiation, on activated CD8+ T cells.Conclusion. In this report we showed that MSCs are able to interact with CD8+ T cells and transfer them their mitochondria. Mitochondrial transfer contributed to the global suppressive effect of MSCs on CD8+ T cell activation by downregulating T-bet and Eomes expression resulting in impaired IFNγ production of activated CD8+ T cells.

The novel secretome ST266 activates Akt and protects against oxidative stress-mediated injury in human RPE and Müller cells

Oxidative stress-mediated retinal pigment epithelial (RPE) cell damage is associated with age-related macular degeneration (AMD). ST266 is the biological secretome produced by a novel population of amnion-derived multipotent progenitor cells. Herein, we investigated the effect of ST266 on RPE cell injury induced by hydroquinone (HQ), a cigarette smoke related oxidant, hydrogen peroxide (H2O2) and all-trans retinal (atRal), a pro-oxidant component of the retinoid cycle. We additionally investigated its effect on Müller cell injury induced by H2O2.Cultured human RPE cells were pre-treated for 1 hour in the presence or absence of MK-2206, a protein kinase B (Akt) inhibitor, then treated with varying concentrations of HQ, H2O2, or atRal for 1.5 hours. Cultured human Müller cells (MIO-M1) were pre-treated for 1 hour in the presence or absence of MK-2206, then treated with varying concentrations of H2O2 for 1.5 hours. Media were then replaced with STM100 (control media into which the ST266 secretome proteins were collected) or ST266 at various times. Cell viability was determined with WST-1 reagent. Mitochondrial membrane potential (Δψm) was quantified by a fluorescence plate reader. The protein phosphorylation levels of Akt, glycogen synthase kinase 3 beta (GSK-3β), and p70 ribosomal S6 kinase (p70S6K) were measured by Western blot.ST266 significantly improved RPE and MIO-M1 cell viability that was reduced by oxidant exposure and improved oxidant-disrupted Δψm. In both cell types, ST266 induced phosphorylation of Akt, GSK-3β, and p70S6K. MK-2206 significantly eliminated ST266-mediated protein phosphorylation of Akt, GSK-3β, and p70S6K and abolished the ST266-protective effect on cell viability. In conclusion, ST266 activates Akt, protects against oxidative stress-mediated cell injury in an Akt-dependent manner, and improves Δψm, suggesting a potential role for ST266 therapy in treating retinal diseases such as AMD.

MITRAL STENOSIS PRESENTATION REVEALING ALARGE LEFT ATRIAL MYXOMA

Introduction: Cardiac myxoma (CM) is the most frequent benign primary cardiac tumor. Around 75% of myxomas originate in the left atrium 20% arise from the right atrium while the remaining 5% are born from both the atria and the ventricle. Atrial myxomas can result in many symptoms: heart failure, systemic or pulmonary embolism, arrhythmias, and conductive disorders, or also constitutional symptoms (such as fever, and weight loss). It largely relies on the tumors size, location, and architecture. It can obstruct the blood flow, mimicking mitral stenosis. The surgical management is the cornerstone of this entity. Case Report: A 63-year-old female with a past medical history of diabetes and arterial hypertension was admitted to our department for palpitations and acute heart failure symptoms.The physical examination revealed an irregular pulse with a tachycardia of 150 bpm. The blood pressure was at 118/80 mmHg. It also revealed lower limb edema, lung crackles, and ascites with a mitral stenosis murmur. EKG showed atrial fibrillation at 150HR . Transthoracic echocardiography found dilated atriums with a large mass in the left atrium causing mitral pseudo stenosis . Discussion: Myxomas are primary cardiac tumors that originate from multipotent mesenchymal cells. They can occur at any age but mostly between 30 and 60 years. The incidence of myxoma in women is 2 to 4 times higher than in men. Clinically, atrial myxomas vary from asymptomatic especially with small tumor size, to non-specific symptoms (dyspnea, lower limb and pulmonary oedema, angina, syncope, and palpitation) and constitutional symptoms such as fever, fatigue, and weight loss. The diagnosis of atrial myxoma based on its presentation is challenging. echocardiography is usually the modality of choice which helps identify the location of the mass whether itÂ’s intra or pericardial, its size, attachment and mobility. Furthermore, it differentiates atrial myxoma from any thrombus or vegetation. Once a presumptive diagnosis of myxoma has been made on imaging studies, prompt resection is required because of the risk of embolization or cardiovascular complications, including sudden death. Conclusion: Myxoma continues to be a significant challenge for emergency physicians due to its non-specific symptoms and overlap with other conditions. The discrepancy between mild symptoms and the serious consequences the condition carries, necessitates high index of suspicion and thorough investigation to timely diagnose it among a long list of differentials.

CXCR4 signaling determines the fate of hematopoietic multipotent progenitors by stimulating mTOR activity and mitochondrial metabolism

Both cell-intrinsic and niche-derived, cell-extrinsic cues drive the specification of hematopoietic multipotent progenitors (MPPs) in the bone marrow, which comprise multipotent MPP1 cells and lineage-restricted MPP2, MPP3, and MPP4 subsets. Patients with WHIM syndrome, a rare congenital immunodeficiency caused by mutations that prevent desensitization of the chemokine receptor CXCR4, have an excess of myeloid cells in the bone marrow. Here, we investigated the effects of increased CXCR4 signaling on the localization and fate of MPPs. Knock-in mice bearing a WHIM syndrome–associated CXCR4 mutation ( CXCR4 1013 ) phenocopied the myeloid skewing of bone marrow in patients. Whereas MPP4 cells in wild-type mice differentiated into lymphoid cells, MPP4s in CXCR4 1013 knock-in mice differentiated into myeloid cells. This myeloid rewiring of MPP4s in CXCR4 1013 knock-in mice was associated with enhanced signaling mediated by the kinase mTOR and increased oxidative phosphorylation (OXPHOS). MPP4s also localized further from arterioles in the bone marrow of knock-in mice compared with wild-type mice, suggesting that the loss of extrinsic cues from the perivascular niche may also contribute to their myeloid skewing. Chronic treatment with the CXCR4 antagonist AMD3100 or the mTOR inhibitor rapamycin restored the lymphoid potential of MPP4s in knock-in mice. Thus, CXCR4 desensitization drives the lymphoid potential of MPP4 cells by dampening the mTOR-dependent metabolic changes that promote myeloid differentiation.

Characterization of Hippo Signaling Components in the Early Dorsal Pancreatic Bud.

YAP1 expression in the early mouse pancreatic anlagen is low until approximately E11.5, when it becomes localized to cell nuclei in multipotent progenitor cells. At E14.5, we find nuclear YAP1 in ductal cells.YAP1 is not expressed in early and midgestation endocrine cells. By contrast, TAZ is expressed in first transition endocrine cells.Hippo regulators MERLIN and LATS1/2 kinases are robustly expressed in the early pancreatic bud by E10.5. Both MERLIN and LATS1/2 exhibit strong apical localization in epithelial cells at nascent microlumens. Using in vitro models of de novo pancreas lumen formation, we show that YAP1 nuclear localization is high in early phases of lumen formation and gradually decreases as lumens matures.

Molecular and Cellular Mechanisms of the Therapeutic Effect of Mesenchymal Stem Cells and Extracellular Vesicles in Corneal Regeneration

The cornea is a vital component of the visual system, and its integrity is crucial for optimal vision. Damage to the cornea resulting from trauma, infection, or disease can lead to blindness. Corneal regeneration using mesenchymal stem cells (MSCs) and MSC-derived extracellular vesicles (MSC-EVs) offers a promising alternative to corneal transplantation. MSCs are multipotent stromal cells that can differentiate into various cell types, including corneal cells. They can also secrete a variety of anti-inflammatory cytokines and several growth factors, promoting wound healing and tissue reconstruction. This review summarizes the current understanding of the molecular and cellular mechanisms by which MSCs and MSC-EVs contribute to corneal regeneration. It discusses the potential of MSCs and MSC-EV for treating various corneal diseases, including corneal epithelial defects, dry eye disease, and keratoconus. The review also highlights finalized human clinical trials investigating the safety and efficacy of MSC-based therapy in corneal regeneration. The therapeutic potential of MSCs and MSC-EVs for corneal regeneration is promising; however, further research is needed to optimize their clinical application.

Topology-defined bioactive properties of porous Ti-6Al-4V scaffolds produced by laser powder bed fusion

The effect of the design of additively printed Ti porous structures on their bioactive properties is elucidated by in vitro testing. 3D-printed scaffolds with pores defined by several bioinspired triply periodic minimal surfaces as well as by a strut model have been engineered. Cell proliferation, angiogenesis and osteogenesis have been studied with the help of multipotent mesenchymal stromal cells. The elementary unit size and pore design can notably modify bioactive properties of porous structures. The models providing maximal bioactive activity of developed scaffolds are discussed.

SMYD1 modulates the proliferation of multipotent cardiac progenitor cells derived from human pluripotent stem cells during myocardial differentiation through GSK3β/β-catenin&ERK signaling.

The histone-lysine N-methyltransferase SMYD1, which is specific to striated muscle, plays a crucial role in regulating early heart development. Its deficiency has been linked to the occurrence of congenital heart disease. Nevertheless, the precise mechanism by which SMYD1 deficiency contributes to congenital heart disease remains unclear. We established a SMYD1 knockout pluripotent stem cell line and a doxycycline-inducible SMYD1 expression pluripotent stem cell line to investigate the functions of SMYD1 utilizing an in vitro-directed myocardial differentiation model. Cardiomyocytes lacking SMYD1 displayed drastically diminished differentiation efficiency, concomitant with heightened proliferation capacityof cardiac progenitor cells during the early cardiac differentiation stage. These cellular phenotypes were confirmed through experiments inducing the re-expression of SMYD1. Transcriptome sequencing and small molecule inhibitor intervention suggested that the GSK3β/β-catenin&ERK signaling pathway was involved in the proliferation of cardiac progenitor cells. Chromatin immunoprecipitation demonstrated that SMYD1 acted as a transcriptional activator of GSK3β through histone H3 lysine 4 trimethylation. Additionally, dual-luciferase analyses indicated that SMYD1 could interact with the promoter region of GSK3β, thereby augmenting its transcriptional activity. Moreover, administering insulin and Insulin-like growth factor 1 can enhance the efficacy of myocardial differentiation in SMYD1 knockout cells. Our research indicated that the participation of SMYD1 in the GSK3β/β-catenin&ERK signaling cascade modulated the proliferation of cardiac progenitor cells during myocardial differentiation. This process was partly reliant on the transcription of GSK3β. Our research provided a novel insight into the genetic modification effect of SMYD1 during early myocardial differentiation. The findings were essential to the molecular mechanism and potential interventions for congenital heart disease.

Transcription factor KROX20 marks epithelial stem cells for hair follicle formation.

Epidermal stem cells control homeostasis and regeneration of skin and hair. In the hair follicle (HF) bulge of mammals, populations of slow-cycling stem cells regenerate the HF during cyclical rounds of anagen (growth), telogen (quiescence), and catagen (regression). Multipotent epidermal cells are also present in the HF above the bulge area, contributing to the formation and maintenance of sebaceous gland and upper and middle portions of the HF. Here, we report that the transcription factor Krox20 is enriched in an epidermal stem cell population located in the upper/ middle HF. Expression analyses and lineage tracing using inducible Krox20-CreERT showed that Krox20-lineage cells migrate out of this HF region and contribute to the formation of bulge in the HF, serving as ancestors of bulge stem cells. In vivo depletion of these cells arrests HF morphogenesis. This study identifies a novel marker for an epidermal stem cell population that is indispensable for hair homeostasis.

Comparison of the Effects of Microfracture, Soft Callus Implantation, and Matrix-Supported Chondrocyte Implantation in an Experimental Osteochondral Defect Model in Rats

Background: The treatment of cartilage defects remains challenging due to the avascular nature of cartilage. Aim: This study investigates the therapeutic effect of soft callus in osteochondral defects and explores the ability of multipotent and pluripotent cells within the callus to form fibrous or hyaline cartilage in the defective area. Methods: Twenty-one rats were divided into three equal groups: Group 1 received only microfracture (MF), group 2 received microfracture with autologous chondrocyte implantation (MF+ACI), and group 3 received microfracture with soft callus implantation (MF+SCI). All rats underwent diaphyseal fracture in their left tibias, which was stabilized with a Kirshner wire. One week later, osteochondral defects were created in the right knees of all rats. For group 1, microfracture alone was applied to initiate healing in the defects. In group 2, heterologous chondrocytes, previously harvested from the lateral condyle of a rat’s left femur and cultivated in a laboratory environment, were implanted into the microfracture site. In group 3, soft callus tissue obtained from the left tibial fracture was compressed and implanted into the defective area. All groups were sacrificed at the 6th week, and the healing status of the osteochondral defect areas was histopathologically evaluated. Results: Macroscopic examination at the end of the study revealed comparable ICRS-1 scores for MF+ACI (group 2) (11.28 ± 1.25) and MF+SCI (group 3) (11.14 ± 0.37), while MF alone (group 1) (4.28 ± 1.25) showed significantly lower results. Microscopic examination yielded similar outcomes. Regarding histological scores, ICRS-2 scores for MF (group 1) (35.30 ± 1.13), MF+ACI (group 2) (47.09 ± 1.63), and MF+SCI (group 3) (43.97 ± 1.49) were statistically significantly lower. Conclusion: Defects treated with soft callus implantation demonstrated comparable outcomes to the widely used and gold-standard autologous chondrocyte implantation. When compared to microfracture alone, better macroscopic and microscopic results were achieved with soft callus implantation.

Effect of Tumor Suppressor Gene Kmt2c Heterozygous Deletion on Hematopoietic System in Mice

To explore the effect of heterozygous deletion of histone methyltransferase Kmt2c gene on the hematological system of mice. CRISPR/Cas9 technology was used to construct mice model of Kmt2c heterozygous deletion (Kmt2c+/-) and the changes of whole blood cell count in mice were continuously monitored by blood routine test. The clonal expansion ability of bone marrow cells was explored by colony formation assay in vitro and the proportion of primitive hematopoietic cells, including long-term hematopoietic stem cell (LT-HSC), short-term hematopoietic stem cell (ST-HSC), and multipotent progenitor cell in mutant mice was analyzed by flow cytometry. Kmt2c+/- mice model was successfully constructed, and the mRNA expression level of Kmt2c was 28% of that of C57BL/6J mice. The colony formation ability of bone marrow cells of Kmt2c+/- mice in vitro increased with the passage times, and the colony number in the fourth generation was significantly higher than that of control group (P <0.05). The proportions of LT-HSC and ST-HSC in the primitive hematopoietic cell population of Kmt2c+/- mice was 19.6%±3.3% and 28.9%±4.9%, respectively, which showed an increasing trend compared with 16.9%±2.6% and 18.9%±2.5% in control group, but the difference was not statistically significant (P >0.05). The white blood cell count of Kmt2c+/- mice gradually increased after 12 weeks of monitoring and reached (9.8±1.0)×109/L at the 14th week, which was significantly higher than (7.3±1.4)×109/L of control group (P < 0.05). The bone marrow cells of Kmt2c+/- mice have potential of clonal expansion.

Cytokine priming enhances the antifibrotic effects of human adipose derived mesenchymal stromal cells conditioned medium

BackgroundFibrosis is a pathological scarring process characterized by persistent myofibroblast activation with excessive accumulation of extracellular matrix (ECM). Fibrotic disorders represent an increasing burden of disease-associated morbidity and mortality worldwide for which there are limited therapeutic options. Reversing fibrosis requires the elimination of myofibroblasts, remodeling of the ECM, and regeneration of functional tissue. Multipotent mesenchymal stromal cells (MSC) have antifibrotic properties mediated by secreted factors present in their conditioned medium (MSC-CM). However, there are no standardized in vitro assays to predict the antifibrotic effects of human MSC. As a result, we lack evidence on the effect of cytokine priming on MSC’s antifibrotic effects. We hypothesize that the MSC-CM promotes fibrosis resolution in vitro and that this effect is enhanced following MSC cytokine priming.MethodsWe compared the antifibrotic effects of resting versus interferon gamma (IFN-γ) and tumor necrosis factor alpha (TNF-α) primed MSC-CM in four in vitro assays: prevention of fibroblast activation, myofibroblasts deactivation, ECM degradation and fibrosis resolution in lung explant cultures. Furthermore, we performed transcriptomic analysis of myofibroblasts treated or not with resting or primed MSC-CM and proteomic characterization of resting and primed MSC-CM.ResultsWe isolated MSC from adipose tissue of 8 donors, generated MSC-CM and tested each MSC-CM independently. We report that MSC-CM treatment prevented TGF-β induced fibroblast activation to a similar extent as nintedanib but, in contrast to nintedanib, MSC-CM reduced fibrogenic myofibroblasts (i.e. transcriptomic upregulation of apoptosis, senescence, and inflammatory pathways). These effects were larger when primed rather than resting MSC-CM were used. Priming increased the ability of MSC-CM to remodel the ECM, reducing its content of collagen I and fibronectin, and reduced the fibrotic load in TGF-β treated lung explant cultures. Priming increased the following antifibrotic proteins in MSC-CM: DKK1, MMP-1, MMP-3, follistatin and cathepsin S. Inhibition of DKK1 reduced the antifibrotic effects of MSC-CM.ConclusionsIn vitro, MSC-CM promote fibrosis resolution, an effect enhanced following MSC cytokine priming. Specifically, MSC-CM reduces fibrogenic myofibroblasts through apoptosis, senescence, and by enhancing ECM degradation. Future studies will establish the in vivo relevance of MSC priming to fibrosis resolution.

Paving the way to a neural fate – RNA signatures in naive and trans-differentiating mesenchymal stem cells

Mesenchymal Stem Cells (MSCs) derived from the embryonic mesoderm persist as a viable source of multipotent cells in adults and have a crucial role in tissue repair. One of the most promising aspects of MSCs is their ability to trans-differentiate into cell types outside of the mesodermal lineage, such as neurons. This characteristic positions MSCs as potential therapeutic tools for neurological disorders. However, the definition of a clear MSC signature is an ongoing topic of debate. Likewise, there is still a significant knowledge gap about functional alterations of MSCs during their transition to a neural fate. In this study, our focus is on the dynamic expression of RNA in MSCs as they undergo trans-differentiation compared to undifferentiated MSCs. To track and correlate changes in cellular signaling, we conducted high-throughput RNA expression profiling during the early time-course of human MSC neurogenic trans-differentiation. The expression of synapse maturation markers, including NLGN2 and NPTX1, increased during the first 24 h. The expression of neuron differentiation markers, such as GAP43 strongly increased during 48 h of trans-differentiation. Neural stem cell marker NES and neuron differentiation marker, including TUBB3 and ENO1, were highly expressed in mesenchymal stem cells and remained so during trans-differentiation. Pathways analyses revealed early changes in MSCs signaling that can be linked to the acquisition of neuronal features. Furthermore, we identified microRNAs (miRNAs) as potential drivers of the cellular trans-differentiation process. We also determined potential risk factors related to the neural trans-differentiation process. These factors include the persistence of stemness features and the expression of factors involved in neurofunctional abnormalities and tumorigenic processes. In conclusion, our findings contribute valuable insights into the intricate landscape of MSCs during neural trans-differentiation. These insights can pave the way for the development of safer treatments of neurological disorders.

Clonal dynamics and somatic evolution of haematopoiesis in mouse.

Haematopoietic stem cells maintain blood production throughout life. While extensively characterised using the laboratory mouse, little is known about how the population is sustained and evolves with age. We isolated stem cells and progenitors from young and old mice, identifying 221,890 somatic mutations genome-wide in 1845 single cell-derived colonies, and used phylogenetic analysis to infer the ontogeny and population dynamics of the stem cell pool. Mouse stem cells and progenitors accrue ~45 somatic mutations per year, a rate only about 2-fold greater than human progenitors despite the vastly different organismal sizes and lifespans. Phylogenetic patterns reveal that stem and multipotent progenitor cell pools are both established during embryogenesis, after which they independently self-renew in parallel over life. The stem cell pool grows steadily over the mouse lifespan to approximately 70,000 cells, self-renewing about every six weeks. Aged mice did not display the profound loss of stem cell clonal diversity characteristic of human haematopoietic ageing. However, targeted sequencing revealed small, expanded clones in the context of murine ageing, which were larger and more numerous following haematological perturbations and exhibited a selection landscape similar to humans. Our data illustrate both conserved features of population dynamics of blood and distinct patterns of age-associated somatic evolution in the short-lived mouse.

Regulation of Skeletal Development and Maintenance by Runx2 and Sp7.

Runx2 (runt related transcription factor 2) and Sp7 (Sp7 transcription factor 7) are crucial transcription factors for bone development. The cotranscription factor Cbfb (core binding factor beta), which enhances the DNA-binding capacity of Runx2 and stabilizes the Runx2 protein, is necessary for bone development. Runx2 is essential for chondrocyte maturation, and Sp7 is partly involved. Runx2 induces the commitment of multipotent mesenchymal cells to osteoblast lineage cells and enhances the proliferation of osteoprogenitors. Reciprocal regulation between Runx2 and the Hedgehog, fibroblast growth factor (Fgf), Wnt, and parathyroid hormone-like hormone (Pthlh) signaling pathways and Dlx5 (distal-less homeobox 5) plays an important role in these processes. The induction of Fgfr2 (Fgf receptor 2) and Fgfr3 expression by Runx2 is important for the proliferation of osteoblast lineage cells. Runx2 induces Sp7 expression, and Runx2+ osteoprogenitors become Runx2+Sp7+ preosteoblasts. Sp7 induces the differentiation of preosteoblasts into osteoblasts without enhancing their proliferation. In osteoblasts, Runx2 is required for bone formation by inducing the expression of major bone matrix protein genes, including Col1a1 (collagen type I alpha 1), Col1a2, Spp1 (secreted phosphoprotein 1), Ibsp (integrin binding sialoprotein), and Bglap (bone gamma carboxyglutamate protein)/Bglap2. Bglap/Bglap2 (osteocalcin) regulates the alignment of apatite crystals parallel to collagen fibrils but does not function as a hormone that regulates glucose metabolism, testosterone synthesis, and muscle mass. Sp7 is also involved in Co1a1 expression and regulates osteoblast/osteocyte process formation, which is necessary for the survival of osteocytes and the prevention of cortical porosity. SP7 mutations cause osteogenesis imperfecta in rare cases. Runx2 is an important pathogenic factor, while Runx1, Runx3, and Cbfb are protective factors in osteoarthritis development.

Effect of the dose, timing, and route of administration of mesenchymal stem cells on their regenerative capacity after myocardial infarction: A systematic review

Background The global rise in cases of acute myocardial infarction (AMI) poses a significant health challenge, which is why adult stem cells have gained great importance in recent years, due to their potential to promote the regeneration of the flowcardiac tissue, among which multipotent mesenchymal stromal cells (MSCs) stand out, thanks to their clinical usefulness. Objectives To evaluate the effect of the dose, timing, and route of administration of MSCs on their regenerative capacity after MI. Methods We searched for randomized clinical trials and experimental studies published up to April 25, 2024, in Medline (PubMed) and Scopus. Results Nine clinical studies were included in the qualitative assessment. The main routes of application were coronary, intramyocardially, epicardial topical and systemic venous perfusion, which could have clinical effectiveness with doses of 1x106 MSC/Kg,1 to 3 x 106, 4x106 and those greater than 0.5x106, respectively. The median number of viable cells administered was 2.4x106 (IQR: 1.6-2.4) in the PCI group versus 1.6x106 in the RCVI group (p=0.167). Median ex vivo retention was 2.55% in the RCVI group, 30 days after AMI, and 39.40% in the PCI group. At 4 and 12 months of follow-up, a better left ventricular end-to-end (LVEF) was observed in the group treated with ADSCs, at 4 (51.8% ±5.4% vs. 35.5% ±1.9%) and 8 weeks (52.1%± 3.4% versus 34.2% ±4.7%, p = 0.048). Conclusions The dosing, timing of administration, and routes of administration were important factors to assess the efficacy of the MSC.

Multifocal, multiphenotypic tumours arising from an MTOR mutation acquired in early embryogenesis.

Embryogenesis is a vulnerable time. Mutations in developmental cells can result in the wide dissemination of cells predisposed to disease within mature organs. We characterised the evolutionary history of four synchronous renal tumours from a 14-year-old girl using whole genome sequencing alongside single cell and bulk transcriptomic sequencing. Phylogenetic reconstruction timed the origin of all tumours to a multipotent embryonic cell committed to the right kidney, around 4 weeks post-conception. Biochemical and structural analysis of their shared MTOR mutation, absent from normal tissues, demonstrates enhanced protein flexibility, enabling a FAT domain hinge to dramatically increase activity of mTORC1 and mTORC2. Developmental mutations, not usually detected in traditional genetic screening, have vital clinical importance in guiding prognosis, targeted treatment, and family screening decisions for paediatric tumours.

Morphological Changes in Tissue When Using Polypropylene Implants with Adsorbed Multipotent Stromal Cells in Experiment.

The subcutaneous tissue of rats after implantation of polypropylene materials with adsorbed bone marrow-derived mesenchymal multipotent stromal cells (MMSCs) was studied using light microscopy. Inflammation in response to implantation was mild, and the foreign material was encapsulated into a thin strip of dense fibrous connective tissue with multinucleated macrophages. By 1 year after introduction of the monofilament and 6 and 12 months after implantation of the mesh product, some threads were deformed, broken, and had sharp edges. Small fragments of foreign material appeared in the adjacent tissues surrounded by their own relatively thick acellular capsule. As a result of preliminary adsorption of MMSCs on polypropylene, the thickness of the connective tissue capsule decreased, its vascularization increased, and the severity of inflammatory infiltration decreased. However, all effects of MMSCs adsorption in rats were transient and disappeared within 1 week.

Quality Assessment of Long-Term Cryopreserved Human Bone-Derived Marrow Mesenchymal Stromal Cell Samples: Experience from the Texas Heart Institute Biorepository and Biospecimen Profiling Core.

In biomedical research, biorepositories are pivotal resources that safeguard and supply clinical samples for scientific investigators. Proper long-term cryopreservation conditions are essential to maintain biospecimen quality. In this study, we analyzed the efficacy of sample cryopreservation at the Texas Heart Institute Biorepository and Biospecimen Profiling Core (THI-BRC). Our assessments included a thorough review of internal processes, quality reports, and both internal and external audit outcomes. We examined the integrity of human bone marrow-derived multipotent mesenchymal stromal cells (BM-MSCs) that were cryopreserved for over 5 years. These samples originated from randomly selected clinical trial participants or commercially sourced cell lines. Parameters such as cell viability, DNA and RNA integrity, population doubling time, sterility, and BM-MSC-specific attributes such as surface antigen expression and differentiation potential were studied. BM-MSC samples cryopreserved for ∼6 months served as our control. Our results demonstrated that the 5-year cryopreserved samples maintained their integrity compared with the shorter-term stored control samples. Moreover, THI-BRC has met accreditation agency standards and has not received any repeated deficiencies over 7 years. Collectively, our findings affirm that THI-BRC's biospecimen storage protocols align with accepted standards as confirmed by the quality assessment of long-term stored clinical samples.

Efficacy and Safety of Bone Marrow Derived Stem Cell Therapy for Ischemic Stroke: Evidence from Network Meta-analysis.

Several types of stem cells are available for the treatment of stroke patients. However, the optimal type of stem cell remains unclear. To analyze the effects of bone marrow-derived stem cell therapy in patients with ischemic stroke by integrating all available direct and indirect evidence in network meta-analyses. We searched several databases to identify randomized clinical trials comparing clinical outcomes of bone marrow-derived stem cell therapy vs. conventional treatment in stroke patients. Pooled relative risks (RRs) and mean differences (MDs) were reported. The surface under the cumulative ranking (SUCRA) was used to rank the probabilities of each agent regarding different outcomes. Overall, 11 trials with 576 patients were eligible for analysis. Three different therapies, including mesenchymal stem cells (MSCs), mononuclear stem cells (MNCs), and multipotent adult progenitor cells (MAPCs), were assessed. The direct analysis demonstrated that stem cell therapy was associated with significantly reduced all-cause mortality rates (RR 0.55, 95% CI 0.33 to 0.93; I2=0%). Network analysis demonstrated MSCs ranked first in reducing mortality (RR 0.42, 95% CrI 0.15 to 0.86) and improving modified Rankin Scale score (MD -0.59 95% CI -1.09 to -0.09), with SUCRA values 80%, and 98%, respectively. Subgroup analysis showed intravenous transplantation was superior to conventional therapy in reducing all-cause mortality (RR 0.53, 95% CrI 0.29 to 0.88). Using stem cell transplantation was associated with reduced risk of death and improved functional outcomes in patients with ischemic stroke. Additional large trials are warranted to provide more conclusive evidence.