Mesenchymal Cells Research Articles

Significance of exosomes in osteosarcoma research: a systematic review and meta-analysis of a singular clinical investigation

BackgroundOsteosarcoma is the most prevalent among primary bone malignancies, and its standard intervention involves neoadjuvant chemotherapy - surgical adjuvant chemotherapy (MAP regimen) with adriamycin, cisplatin, and high-dose methotrexate. Early-stage osteosarcoma can be effectively treated with surgical resection along with chemotherapy or radiotherapy. However, as the cancer progresses, the efficacy of chemo- and radiotherapy decreases, and the associated problems increase. The current understanding of osteosarcoma development, diagnosis, and treatment does not meet clinical demands. More recently, there has been a significant increase in exosome-associated osteosarcoma research, potentially opening up novel possibilities for osteosarcoma research.PurposeWe comprehensively evaluated and analyzed the advancement of preclinical research related to exosome-osteosarcoma. We aimed to establish a practical, theoretical foundation for future research initiatives.Study designThe selected design was a systematic review and meta-analysis.MethodsScientific databases, such as PubMed, Embase, The Cochrane Library, and Web of Science, were extensively screened for exosome and osteosarcoma articles. Two highly trained investigators separately reviewed the literature, extracted relevant information, and assessed study quality. Subsequently, we conducted a meta-analysis using Review Manager 5.4.ResultsIn total, 25 animal-based randomized controlled trials (RCTs) were selected for analysis. Among them, 13 studies provided strong evidence of cellular exosomes regulating osteosarcoma development from bone marrow mesenchymal stem cells, osteosarcoma cells, and macrophages. In addition, 12 studies demonstrated the therapeutic potential of exosomes in managing osteosarcoma, among which 7 studies transplanted transfected exosomes directly into animals as drugs, and five studies employed exosomes as drug carriers, which were next transplanted into animals.ConclusionBased on our meta-analysis, macrophages strongly modulate osteosarcoma development, and engineered exosomes provide the most effective exosome-based osteosarcoma treatment.

Preclinical safety and efficacy evaluation of the intrathecal transplantation of GMP-grade human umbilical cord mesenchymal stem cells for ischemic stroke

Intrathecal administration of human umbilical cord mesenchymal stem cells may be a promising approach for the treatment of stroke, but its safety, effectiveness, and mechanism remain to be elucidated. In this study, good manufacturing practice–grade human umbilical cord mesenchymal stem cells (5 × 105 and 1 × 106 cells) and saline were administered by cerebellomedullary cistern injection 72 hours after stroke induced by middle cerebral artery occlusion in rats. The results showed (1) no significant difference in mortality or general conditions among the three groups. There was no abnormal differentiation or tumor formation in various organs of rats in any group. (2) Compared with saline-treated animals, those treated with human umbilical cord mesenchymal stem cells showed significant functional recovery and reduced infarct volume, with no significant differences between different human umbilical cord mesenchymal stem cell doses. (3) Human umbilical cord mesenchymal stem cells were found in the ischemic brain after 14 and 28 days of follow-up, and the number of positive cells significantly decreased over time. (4) Neuronal nuclei expression in the human umbilical cord mesenchymal stem cell group was greater than that in the saline group, while glial fibrillary acidic protein and ionized calcium binding adaptor molecule 1 expression levels decreased. (5) Human umbilical cord mesenchymal stem cell treatment increased the number of CD31+ microvessels and doublecortin-positive cells after ischemic stroke. Human umbilical cord mesenchymal stem cells also upregulated the expression of CD31+/Ki67+. (6) At 14 days after intrathecal administration, brain-derived neurotrophic factor expression in the peri-infarct area and the concentrations of brain-derived neurotrophic factor in the cerebrospinal fluid in both human umbilical cord mesenchymal stem cell groups were significantly greater than those in the saline group and persisted until the 28th day. Taken together, these results indicate that the intrathecal administration of human umbilical cord mesenchymal stem cells via cerebellomedullary cistern injection is safe and effective for the treatment of ischemic stroke in rats. The mechanisms may include alleviating the local inflammatory response in the peri-infarct region, promoting neurogenesis and angiogenesis, and enhancing the production of neurotrophic factors.

Abstract 4147630: Towards transplantation of hearts from donation after circulatory death - stem cell derived therapy for ameliorating donor organ damage

The use of heart transplantation (HTx), a key life-saving therapy for end-stage heart failure, is limited by the shortage of acceptable donor hearts. Although donation after circulatory death (DCD) offers a potentially promising resource for clinical transplantation, its adoption for HTx is concerned by warm ischemic damage during the death process. Mesenchymal stem cell (MSC)-derived paracrine action has been proved to mediate cardioprotection. Based on our previous study showing that MSC conditioned media (MSC CM) and MSC-exosomes (MSC Exo) confer improved donor heart preservation during cold ischemic storage, we aimed to test the effect of MSC CM and MSC Exo on ex vivo recovery of ischemia-damaged myocardium and on promoting the implanted DCD heart function using an in vivo murine heterotopic heart transplantation model. Methods: Donor hearts from adult male C57BL/6 mice with 0, 30’ or 50’ in vivo warm ischemia (WI) were divided into (n=5-7/group): 1) no WI; 2) 30’-WI; 3) 50’-WI; 4) no WI+4h cold storage at 0-4°C (no WI+CS); 5) 30’-WI+CS; 6) 50’-WI+CS; 7) 50’-WI+CS+vehicle; 8) 50’-WI+CS+MSC CM; and 9) 50’-WI+CS+MSC Exo. The CM and Exo were obtained from cultivation of human bone marrow-MSCs in serum-free media for 72h and was added into preservation solution. Donor hearts were implanted into C57BL/6 male recipients using cervical heterotopic heart transplantation. At 24h post-surgery, left ventricular (LV) function was detected in transplanted hearts. Abdominal artery pressure was measured in recipients to validate technical reproducibility of the HTx model. Mitochondrial structure was detected by electron microscopy on the fixed human LV (hDCD&hDBD). Results: WI significantly impaired LV function in transplanted DCD hearts vs. no-WI (Fig. A, B). Intriguingly, markedly improved graft function was observed in MSC CM- or Exo-treated DCD hearts vs. vehicle (Fig. C). Short and disrupted cristae in mitochondria were noticed in hDCD vs. hDBD (Fig. D). Conclusions: Our results represent the initial evidence that MSC secretome (CM&Exo) mediates ex vivo cardiac repair in DCD hearts and validate an approach on MSC derived therapy to rescue marginal DCD donor hearts and improve post-transplant graft function.

Antineoplastic therapy affects the in vitro phenotype and functionality of healthy human bone marrow-derived mesenchymal stromal cells.

While antineoplastic therapies aim to specifically target cancer cells, they may also exert adverse effects on healthy tissues, like healthy hematopoietic stem and progenitor cells (HSPC), leading to hematotoxicity as a common side effect. Mesenchymal stromal cells (MSC) are a major component of the bone marrow (BM) microenvironment, regulating normal hematopoiesis, while their susceptibility to anticancer therapies and contribution to therapy-related hematotoxicity remains largely unexplored. To address this, we investigated the effects of etoposide, temozolomide, 5-azacitidine, and venetoclax on healthy BM-derived MSC functionality. Doses below therapeutic effects of etoposide (0.1-0.25µM) inhibited cellular growth and induced cellular senescence in healthy MSC, accompanied by an increased mRNA expression of CDKN1A, decreased trilineage differentiation capacity, and insufficient hematopoietic support. Pharmacological doses of 5-azacitidine (2.5µM) shifted MSC differentiation capacity by inhibiting osteogenic capacity but enhancing the chondrogenic lineage, as demonstrated by histochemical staining and on mRNA level. At the highest clinically relevant dose, neither venetoclax (40nM) nor temozolomide (100µM) exerted any effects on MSC but clearly inhibited cellular growth of cancer cell lines and primary healthy HSPC, pointing to damage to hematopoietic cells as a major driver of hematotoxicity of these two compounds. Our findings show that besides HSPC, also MSC are sensitive to certain antineoplastic agents, resulting in molecular and functional alterations that may contribute to therapy-related myelosuppression. Understanding these interactions could be helpful for the development of strategies to preserve BM MSC functionality during different kinds of anticancer therapies.

Abstract 4137935: Adipogenesis in Bone Marrow Niche under Cardiac Stress Worsens Cardiac Function

Background: We have recently reported that repetitive cardiac decompensation with multimorbidity often experienced by patients with heart failure (HF) is attributed to epigenetic modifications of hematopoietic stem cells (HSCs) in the bone marrow (BM). HF reprogrammed HSCs differentiation and altered tissue macrophage homeostasis. These findings demonstrate that the BM can carry an innate immune memory of cardiac stress that may exacerbate HF and predispose other organs to pathology. Aims: Because the stemness of HSCs is mainly regulated by mesenchymal stromal cells (MSCs) in the BM niche, we investigated phenotypic alterations of MSCs under cardiac stress. Methods&Results: Transcriptome analysis of MSCs showed preferential differentiation toward adipocytes in murine pressure overload models. In vitro assays and histological BM sections also support this finding. Furthermore, single-cell RNA sequencing of MSCs demonstrated that the percentage of adipocyte-primed MSCs increased in proportion to the severity of cardiac dysfunction, and also correlated with the frequency of myeloid-lineage progenitor cells. To investigate the influence of adipo-lineage MSCs on HSCs, we conducted BM transplantation supplemented with MSCs from control or HF mice. Recipient mice transplanted with HF-MSCs showed significant increases in myeloid-biased multipotent progenitors in BM and myeloid cells in peripheral blood. Additionally, the number of proinflammatory cardiac macrophages was significantly increased in the HF-MSCs group, promoting cardiac fibrosis and dysfunction. Conclusions: Our results demonstrated that the BM niche could perceive cardiac stress in the form of adipocytic skewing of MSCs in the setting of HF, which changed the differentiation behavior in HSCs and ultimately led to further deterioration of cardiac function through the impaired differentiation of circulating monocytes into cardiac macrophages. Therefore, suppressing the adipocytic differentiation of MSCs could have a novel therapeutic potential to avoid repeated HF events.

Regenerative capacity of dental mesenchymal stem cells: a systematic review

Background: Oral mesenchymal cells already have wide clinical applications based on their tissue regenerative abilities. The purpose of this study is to present the picture of scientific research on the application of mesenchymal cells. Methods: This review study presents data processing of selected articles on clinical application of oral mesenchymal cells as a future of technology with relatively reduced cost. As inclusion criteria, there are articles that evaluated the regenerative abilities of cells prior to their oral origin. The exclusion criteria are mainly laboratory procedural techniques of manipulation with mesenchymal cells. From 735 articles screened for retrieval, 148 articles were found. After application of exclusion criteria, it was reached in total, about 38 selected articles were analyzed based on combinations of keywords on the PubMed page. These articles were classified based on concrete positive results and evasive results of studies on the role, mechanism of action, and field of application of oral mesenchymal cells. Results: The selection ratio of mesenchymal cells of pulpal origin or of periodontium origin is based on the first type of cells. Regardless of the fact that the trend of their application is again in the oral cavity, in a smaller percentage they tend to be applied for tissue regeneration in other organs. Discussion: There is a lack of “in vivo” type studies. The trend of articles is about review-type studies on the field of application of oral mesenchymal cells. Articles, where the field of application of mesenchymal cells is beyond the oral cavity for the purpose of application in regenerative medicine, occupy a reduced percentage. There are significant differences between differentiating abilities depending on the source from which these cells are taken from the oral cavity. This ability can be modeled by using growth factors, cytokines, bioactive substances, or local anesthetics.

Biocompatibility and antibacterial properties of medical stainless steel and titanium modified by alumina and hafnia films prepared by atomic layer deposition.

New methods for producing surfaces with suitable biocompatible properties are desirable due to increasing demands for biomedical devices. Stainless steel 316 L and cp- titanium specimens were coated with thin films of alumina and hafnia deposited using the atomic layer deposition method at two temperatures, 180 and 260 °C. The morphology of the films was analysed using scanning electron microscopy, and their surface energies were determined based on drop contact angle measurements. Biocompatibility assays performed using mesenchymal stem cells were evaluated by incubating the specimens and then exposing their extracts to the cells or directly seeding cells on the specimen surfaces. No detrimental effect was noticed for any of the specimens. Antibacterial properties were tested by directly incubating the specimens with the bacteria Staphylococcus aureus. Overall, our data show that all prepared films were biocompatible. Alumina films deposited on cp-titanium at 260 °C outperform the other prepared and tested surfaces regarding antiadhesive properties, which could be related to their low surface energy.

Implantable 3D printed hydrogels with intrinsic channels for liver tissue engineering

This study presents the design, fabrication, and evaluation of a general platform for the creation of three-dimensional printed devices (3DPDs) for tissue engineering applications. As a demonstration, we modeled the liver with 3DPDs consisting of a pair of parallel millifluidic channels that function as portal-venous (PV) and hepatobiliary (HB) structures. Perfusion of medium or whole blood through the PV channel supports the hepatocyte-containing HB channel. Device computer-aided design was optimized for structural stability, after which 3DPDs were 3D printed in a polyethylene(glycol) diacrylate photoink by digital light processing and evaluated in vitro. The HB channels were subsequently seeded with hepatic cells suspended in a collagen hydrogel. Perfusion of 3DPDs in bioreactors enhanced the viability and function of rat hepatoma cells and were maintained over time, along with improved liver-specific functions. Similar results were observed with primary rat hepatocytes, including significant upregulation of cytochrome p450 activity. Additionally, coculture experiments involving primary rat hepatocytes, endothelial cells, and mesenchymal stem cells in 3DPDs showed enhanced viability, broad liver-specific gene expression, and histological features indicative of liver tissue architecture. In vivo implantation of 3DPDs in a rat renal shunt model demonstrated successful blood flow through the devices without clot formation and maintenance of cell viability. 3D printed designs can be scaled in 3D space, allowing for larger devices with increased cell mass. Overall, these findings highlight the potential of 3DPDs for clinical translation in hepatic support applications.

Unveiling three accessory spleens in one patient: a rare case report and literature review.

During embryogenesis, the spleen undergoes intricate developmental processes, originating from mesenchymal cells in the dorsal mesentery. An accessory spleen, a common anomaly found in autopsies and abdominal CT scans, can often be mistaken for different types of tumors. To the best of our knowledge, this is the first case in Syria documenting the occurrence of 3 accessory spleens in a patient who had previously undergone splenectomy. A 33-year-old male presented with right hypochondrium pain, sharp and radiating to the right flank, exacerbated by movement and large meals. Past medical history included mild Irritable Bowel Syndrome (IBS) and splenectomy due to a traumatic accident in childhood. On admission, vital signs were stable, with abdominal tenderness in the right upper quadrant. Laboratory investigations showed normal values. Ultrasound revealed a lobulated mass at the right adrenal gland (4.5 × 5cm) with an isoechoic to hypoechoic texture. Multi-slice computed tomography (MSCT) Scan showed multiple nodules in the right adrenal gland, regular in shape, exerting a compressive mass effect, and significant lymphadenopathy around the abdominal aorta. Elevated metanephrine levels raised suspicion of an extra-adrenal pheochromocytoma. Laparoscopic surgery was performed, revealing accessory spleens and normal adrenal tissue with no malignancy. Healthcare providers should consider accessory spleens as a differential diagnosis for masses near the adrenal glands. Multiple accessory spleens in the adrenal region can complicate cases. Accessory spleens in uncommon locations like the adrenal glands can be challenging to diagnose and manage.

The Bi-Steric Inhibitor RMC-5552 Reduces mTORC1 Signaling and Growth in Lymphangioleiomyomatosis.

Mutations in the Tuberous Sclerosis Complex (TSC) genes result in the hyperactivation of the mechanistic/mammalian target of rapamycin 1 (mTORC1) growth pathway in mesenchymal pulmonary cells. Rapamycin (SirolimusTM), a naturally occurring macrolide, is the only therapeutic approved for women with lymphangioleiomyomatosis (LAM), a progressive, destructive lung disease caused by TSC gene mutations and mTORC1 hyperactivation. However, on cessation of the drug, lung function decline continues. We demonstrated here that pulmonary LAM cancer stem-like cells (SLS) most highly expressed the eukaryotic translation initiation factor 4E (eIF4E)-dependent translation initiation genes. We also showed that the eukaryotic initiation factor 4E-binding protein 1 (4E-BP1) gene has the lowest expression in these cells, indicating that the 4E-BP1/eIF4E ratio in LAM SLS cells favors unrestrained eIF4E oncogenic mRNA translation. The bi-steric mTORC1-selective compound RMC-5552 prevented growth of LAM-associated fibroblasts (LAFs) and phosphorylation of proteins in the ribosomal protein S6K1/ribosomal protein S6 (S6K1/S6) and 4E-BP1/eIF4E translation mTORC1-driven pathways, whereas rapamycin only blocked the S6K/S6 axis. Rapamycin inhibition of LAF growth was rapidly reversed, but RMC-5552 inhibition was more durable. RMC-5552, through its potential to eradicate LAM cancer SLS cells, may have therapeutic benefit in LAM and other diseases with mTORC1 hyperactivity.

A novel electrochemiluminescent cytosensor using dual-target magnetic probe recognition and nanozymes-catalyzed cascade signal amplification for precise phenotypic enumeration of CTCs.

The inability of surgical biopsy to monitor the dynamic evolution of cancer cells hampers its capacity to reflect real-time tumor heterogeneity. Circulating tumor cells (CTCs), as a crucial target in liquid biopsy, offer a novel approach for accurate monitoring of tumors. However, the rarity and complex phenotype resulting from epithelial-mesenchymal transition pose challenges for conventional methods such as CellSearch and immunohistochemistry, which have insufficient ability for simultaneous phenotyping and enumeration of CTCs. The enumeration of a single phenotype CTCs is insufficient for accurately assessing disease progression. Herein, we propose a strategy to address this issue by fabricating an electrochemiluminescence cytosensor via the integration of dual-target enrichment and nanozymes-catalyzed cascade signal amplification. The graphene oxide@hollow mesoporous Prussian blue/Pt (GO@HMPB/Pt) complex, possessing a large specific surface area and exceptional catalytic activity, is employed for loading a substantial amount of luminol as the signal probe. Dual-target magnetic PPy@Fe3O4/Au-antibody/aptamer is utilized for the magnetic capture of both epithelial and interstitial CTCs. Glutathione (GSH) can disrupt theAu-S bond on aptamer by a thiol exchange reaction and selectively releases a specific subset of phenotypic CTCs, thereby facilitating the efficient capture, accurate classification, and ultrasensitive detection of CTCs in peripheral blood. Using the epithelial MCF-7 and mesenchymal Hela cells as models, the ECL cytosensor demonstrates excellent performance in identifying cells spiked into whole blood. This study presents a novel approach for early detection of metastasis, tracking tumor recurrence, and monitoring therapeutic efficacy.

Abstract 4136901: Mechanosensitive channel protein Piezo1 synergizes with TLR4 to enhance osteogenic responses in human aortic valve interstitial cells

Background: Calcific aortic valve disease (CAVD), a common heart valve disease in the elderly, has a complex pathogenesis. Abnormal blood flow shear can be regarded as an important factor in the development of CAVD, and a key molecule that responds to mechanical stress is the mechanosensitive ion channel protein Piezo1; however, the role of Piezo1 in CAVD has not been clarified. Methods and results: We collected CAVD patients and their age- and sex-matched controls, and compared the differences in the protein expression levels of Piezo1 and TLR4 between the two using Western blot and other techniques, and found that the expression of Piezo1 and TLR4 proteins was elevated in the CAVD group. We gave LPS or Piezo1 agonist Yoda1 to stimulate aortic valve mesenchymal stromal cells, respectively, and the Western blot results showed that ALP and Runx2 expression were elevated after LPS and Yoda1 stimulation, and immunofluorescence and alizarin red staining showed similar results. Inhibition of TLR4 or Piezo1 attenuated the osteogenic differentiation of AVICs. Cellular immunofluorescence results showed that TLR4 could be transported from the Golgi to the cell membrane under Yoda stimulation, and Golgi-cell membrane transport of TLR4 was attenuated after Rab3b knockdown by siRNA. After first pre-stimulation with Yoda1 and then stimulation with LPS, Western blot and immunofluorescence results showed that the protein levels of ALP and Runx2 as well as NF-κB phosphorylation were to be significantly increased. Conclusion: Stimulation of Piezo1 and TLR4 can enhance the osteogenic response of AVICs. Stimulation of Piezo1 enhances the transport of TLR4 from the Golgi to the cell membrane via Rab3b, and Piezo1 synergistically enhances the osteogenic response of AVICs with TLR4, thus promoting the development of CAVD.

Mesenchymal Stem Cell Therapy to Reduce the Neurological Deficit of Chronic Ischemic Stroke Patients: A Systematic Review

Current ischemic and hemorrhagic stroke treatments are limited by a narrow golden period and lack of regenerative benefits, so stem cell therapy emerges as an ideal candidate for functional recovery in stroke patients. Stem cell therapy, still being studied, is expected to repair ischemic areas damaged by stroke to restore their physiological functions and reduce neurological deficits in chronic stroke patients. This study aimed to determine the therapeutic efficacy of MSCs in reducing neurological deficits in chronic ischemic stroke patients. We conducted a systematic review. We searched PubMed, Cochrane Library, Science Direct, and Springer Link from inception until December 2022 for cohort studies dealing with mesenchymal stem cell therapy for patients with ischemic stroke. The citation-searching method in this study collected 1,038 articles using the advanced searching method and 8 articles using the citation-searching method, bringing the total number of articles to 1,046. The exclusion criteria used were articles with systematic reviews and meta-analyses and articles that were not accessible in full text. Based on the results of a systematic review study conducted, the conclusion that can be drawn is that MSCs therapy has proven effective in reducing neurological deficits in chronic ischemic stroke patients in terms of the decreased NIHSS score.

Bone marrow mesenchymal stem cell-derived exosomes improve cancer drug delivery in human cell lines and a mouse osteosarcoma model

IntroductionOsteosarcoma is the most common primary bone tumor. Patients require chemotherapy drugs with high-targeting ability and low off-target toxicity to improve their survival. Exosomes are biological vesicles that mediate long-distance communication between cells and naturally target their source sites. Exosomes derived from bone marrow mesenchymal stem cells (BMSCs) naturally target bone tumor sites, suggesting their potential as effective anti-tumor therapy vectors. In this study, we evaluated the potential of BMSC-derived exosomes in targeting osteosarcoma and serving as a carrier for doxorubicin (DOX).MethodsWe isolated exosomes from human BMSCs and synthesized hybrid exosomes (HEs) by fusing these exosomes with liposomes. These HEs were loaded with DOX to produce a novel drug, HE/DOX.ResultsWe confirmed the successful synthesis of HE/DOX using fluorescence spectroscopy and estimated its size to be 151.1 ± 10.2 nm. HEs expressed the known exosomal proteins ALIX, CD63, and TSG101. Under acidic conditions similar to those observed in the tumor microenvironment, the drug release from HE/DOX was enhanced. In osteosarcoma cell lines and in a mouse osteosarcoma model, HE/DOX exhibited stronger tumor-inhibitory effects than free DOX.ConclusionsOur study demonstrates that BMSC-derived exosomes could effectively target osteosarcoma. Furthermore, HEs can serve as effective carriers of DOX, enabling the treatment of osteosarcoma. These findings highlight a promising direction for tumor-targeted therapy.

Abstract 4138344: High fat diet induced the premature senescence of white adipose tissue through downregulating SIRT1 expression and promoting its S-nitroslyation modification

Background and Objectives: The dysfunction of subcutaneous white adipose tissue is one of the early manifestations of obesity, which was associated with accelerated cellular process in aging induced by high fat-diet. The premature senescence of adipose-derived mesenchymal stem cells (AMSCs) is the key factor contributing to the aging of subcutaneous white adipose tissue. However, the underlying mechanism was not clear. Here, we explored the role and mechanism of obesity on the aging of white adipose tissue and AMSCs, and evaluated the anti-aging effect of resveratrol on this process. Methods: Subcutaneous white adipose tissue in non-elderly obese individuals and mice fed with high fat-diet was obtained to detect the TG metabolism and premature senescence. Then the postprandial triglyceride-rich lipoproteins (TRL) after high-fat diet was extracted, and the role and mechanism of TRL on the senescence of AMSCs were explored. Finally, the anti-aging effect of resveratrol on the white adipose tissue and AMSCs was evaluated. Results: Postprandial TG metabolism was abnormal in non-elderly obese humans and mice, and high-fat diet remarkably aggravated white adipose tissue senescence in mice (Fig. 1). TRL induced the premature senescence of AMSCs, with the downregulation of of silent mating-type information regulation 2 homolog 1 (SIRT1) via protein kinase B/forkhead box protein O1 pathway. Besides, the S-nitrosylation of SIRT1 was increased which was regulated by ten-eleven translocation 1/S-nitrosoglutathione reductase pathway. Resveratrol, a SIRT1 agonist, inhibited the TRL-induced AMSCs senescence, resulting in the amelioration of white adipose tissue senescence in obese mice (Fig. 2). Conclusions: These findings established a new mechanism for high-fat diet-induced white adipose tissue senescence and provided a potential therapeutic strategy for high-fat diet induced white adipose tissue senescence and metabolic disorders.

Abstract 4129182: Transendocardial Stem Cell Therapy Improves Cardiac Parameters in Chronic Ischemic Heart Failure: A Meta-analysis of Randomized Controlled Trials

Introduction: Despite recent advances in therapy, chronic ischemic heart failure remains a significant cause of morbidity and mortality worldwide. Stem cell (SC) therapy has recently emerged as a potential therapeutic approach, yet its efficacy remains debatable. We aimed to systematically review and meta-analyze the current evidence to evaluate its effectiveness. Methods: A comprehensive literature search was conducted across the following databases: PubMed, Embase, and Cochrane, from inspection to April 2024. We identified RCTs with a blinded study design, done on patients diagnosed with chronic ischemic HFrEF, and utilized mesenchymal stem cells as an intervention in comparison to placebo/sham intervention using percutaneous endomyocardial catheter systems. Meta-analysis was conducted using RevMan v5.4 to calculate the odds ratio (OR) at 95% confidence intervals (CI) and a p-value of 0.05. I 2 was indicated for the assessment of heterogeneity. Sensitivity analysis was done in case of heterogeneity between studies. Results: A total of twenty studies were included in our meta-analysis. The overall change in left ventricular end-systolic volume (LVESV) and stress SPECT significantly favored the stem cell group (pooled effect size -7.59, 95% CI [-12.28 to -2.89], P=0.002), and (pooled effect size -5.33, 95% CI [-6.73 to -3.93], P=0.00001), respectively. Initially, the change in left ventricular end-diastolic volume (LVEDV) did not favor either group. However, sensitivity analysis which excluded one study at a time, reduced heterogeneity (P=0.01, I 2 =54%) and showed a significant effect favoring the stem cell group (pooled effect size -3.87, 95% CI [-6.77 to -0.97], P=0.009). However, the overall changes in left ventricular ejection fraction (LVEF) did not favor either of the two groups (pooled effect size 0.08, 95% CI [-0.1 to 0.26], P=0.39). Similarly, the overall change in myocardial oxygen consumption (MVO2) did not favor either group (pooled effect size 0.66, 95% CI [-0.1 to 1.32], P=0.05). Conclusion: Transendocardial SC therapy demonstrates promising results by significantly improving specific cardiac parameters. While the therapy shows potential, particularly after sensitivity adjustments, its impact on other critical measures like LVEF and MVO2 remains inconclusive. These findings highlight the need for further investigation to fully understand and enhance the therapeutic potential of stem cell interventions in heart failure management.

High-Yield Bioproduction of Extracellular Vesicles from Stem Cell Spheroids via Millifluidic Vortex Transport.

Extracellular vesicles (EVs) are emerging as novel therapeutics, particularly in cancer and degenerative diseases. Nevertheless, from both market and clinical viewpoints, high-yield production methods using minimal cell materials are still needed. Herein, a millifluidic cross-slot chip is proposed to induce high-yield release of biologically active EVs from less than three million cells. Depending on the flow rate, a single vortex forms in the outlet channels, exposing transported cellular material to high viscous stresses. Importantly, the chip accommodates producer cells within their physiological environment, such as human mesenchymal stem cells (hMSCs) spheroids, while facilitating their visualization and individual tracking within the vortex. This precise control of viscous stresses at the spheroid level allows for the release of up to 30000 EVs per cell at a Reynolds number of ≈400, without compromising cellular integrity. Additionally, it reveals a threshold initiating EV production, providing evidence for a stress-dependent mechanism governing vesicle secretion. EVs mass-produced at high Reynolds displayed pro-angiogenic and wound healing capabilities, as confirmed by proteomic and cytometric analysis of their cargo. These distinct molecular signatures of these EVs, compared to those derived from monolayers, underscore the critical roles of the production method and the 3D cellular environment in EV generation.

Bilayer Scaffolds Synergize Immunomodulation and Rejuvenation via Layer-Specific Release of CK2.1 and the "Exercise Hormone" Lac-Phe for Enhanced Osteochondral Regeneration.

Repairing osteochondral defects necessitates the intricate reestablishment of the microenvironment. The cartilage layer consists of a porous gelatin methacryloyl hydrogel (PGelMA) covalently crosslinked with the chondroinductive peptide CK2.1 via a "linker" acrylate-PEG-N-hydroxysuccinimide (AC-PEG-NHS). This layer is optimized for remodeling the senescent microenvironment in the cartilage region, thereby establishing a regenerative microenvironment that supports chondrogenesis. For the bone layer, silk fibroin methacryloyl (SilMA) is coated onto a three dimensional (3D)-printed 45S5 bioactive glass scaffold (BG scaffold). The "exercise hormone" N-lactoyl-phenylalanine (Lac-Phe) is loaded onto the SilMA, endowing it with diversified functions to regulate the osteogenic microenvironment. Systematic analysis in vitro reveals that PGelMA-CK2.1 shifts the microenvironment from a pro-inflammatory into an anti-inflammatory condition, and alleviates cellular senescence, thus modifying the cartilage microenvironment to improve the recruitment, proliferation and chondral differentiation of bone marrow mesenchymal stem cells (BMSCs). The scaffold bone layer enhances microvascular endothelial cell proliferation, migration, and angiogenic activities, which, couple with increased BMSC recruitment and regulatory mechanisms directing BMSC differentiation, favor a shift in the "osteogenesis-adipogenesis" balance toward enhanced osteogenesis. In vivo, it is found that this biphasic biomimetic scaffold favors simultaneous dual tissue regeneration. This approach facilitates the development of bioactive regenerative scaffolds and holds great potential for clinical application.

Human platelet lysate combined with mesenchymal stem cells pretreated with platelet lysate improved cardiac function in rats with myocardial infarction.

Myocardial infarction (MI) is a leading cause of heart failure, disability and mortality worldwide. In this study, the effects of intramyocardial injection of human platelet lysate (HPL), bone marrow mesenchymal stem cells pretreated with HPL (PMSCs), and PMSC lysate (lys), alone and in combination were investigated on MI-induced by LAD ligation in male Wistar rats. The experiment was carried out on sham, vehicle (Veh), HPL, PMSCs, PMSC lysate (PMSC lys), HPL + PMSCs, and HPL + PMSC lys groups. SBP, DBP, and ± dp/dt max were monitored by the PowerLab physiograph. The MSC characteristics and CD31, NKX2.5, and cardiac troponin I (cTnI) contents were determined by flow cytometry, immunohistochemistry, and immunofluorescence, respectively. SBP, DBP, and ± dp/dt max that decreased in the MI group were recovered by HPL, PMSC, PMSC lys, HPL + PMSC, and HPL + PMSC lys treatments. CD31 density was higher in all treated groups compared to the Veh group. CD31 density in the HPL + PMSCs and HPL + PMSC lys groups was higher than in the PMSCs group. The number of Dil+/NKX2.5 + and Dil+/cTnI + cells was higher in the HPL + PMSCs group compared to the PMSCs group. The HPL and PMSCs mitigates heart injuries and cardiac dysfunction after MI. HPL provides an appropriate environment for cardiomyocyte differentiation from PMSCs.

Abstract 4123639: Tumor Endothelial Marker 1 is Upregulated in Atrial Cardiac Fibroblasts in Atrial Fibrillation and Correlates With Atrial Fibrosis

Background: Tumor endothelial marker 1 (TEM1 or CD248) is a transmembrane protein found in activated mesenchymal cells during embryo development. Its expression level becomes very low or undetectable in adult tissue. Re-expression of TEM1 in fibroblasts has been reported in hepatic, renal, and pulmonary fibrosis. We evaluated atrial TEM1 expression in atrial fibrillation (AF) and its relation with atrial fibrosis. Methods and Results: All data were presented as mean±standard error. Left atrial (LA) tissues were collected from 30 patients (pts) (mean age 64.0±1.6 yrs, male 76.7%) with AF underwent cardiac surgery (mitral and/or tricuspid valve surgery 96.7%) and maze procedure with LA appendage excision. Immunofluorescence (IF) staining showed TEM1 expressed in atrial cardiac fibroblasts (CFs) in the LA tissue of AF pts, but not in normal LA tissue (US Biomax). Primary human CFs were directly isolated from the LA tissue. IF staining showed TEM1 expression in the isolated CFs from AF pts but not in normal human CFs (ScienCell). Western blot could detect TEM1 expression in the LA tissues of all 30 AF pts. Sirius Red staining was used to visualize collagen and atrial fibrosis was quantified using a pixel-based method (Adobe Photoshop) by calculating the total numbers of red pixels and the percentage (%) of red pixels to total pixels. Atrial fibrosis was increased in AF pts compared with normal control (total number of red pixels: 160740±13066 vs. 50863±6357, % of red pixels to total pixels: 11.4±0.8 vs. 3.8±0.2%, all p<0.001). There was a positive correlation between the expression level of TEM1 (ratio of TEM1/actin band density in western blot) with the severity of atrial fibrosis, including the total numbers of red pixels (r = 0.47, p = 0.01) and the % of red pixels to total pixels (r = 0.48, p = 0.01). TEM1 and galectin expression levels had positive correlation (r = 0.60, p < 0.01). There were no correlations of atrial TEM1 expression with the LA diameter and CHA2DS2-VASc score. In vitro study showed TEM1 knockdown in cultured CFs with siRNA reduced cell proliferation (scrambled- vs TEM1-siRNA, BrdU absorbance: 1.84±0.05 vs 1.50±0.07, p<0.05), increased starvation-induced cell apoptosis (cell death ELISA absorbance: 0.69±0.11 vs 2.88±0.05, p<0.05) and decreased cell migration. Conclusions: There is increased TEM1 expression in atrial CFs in AF and its expression level is associated with atrial fibrosis. TEM1 expression changes the cell behaviors of CFs.