Acute Myocardial Infarction Reduces Respiration in Rat Cardiac Fibers, despite Adipose Tissue Mesenchymal Stromal Cell Transplant

Ghrelin promotes cardiomyocyte differentiation of adipose tissue‑derived mesenchymal stem cells by DDX17‑mediated regulation of the SFRP4/Wnt/β‑catenin axis

Adipose tissue‑derived mesenchymal stem cells (ADMSCs) differentiate into cardiomyocytes and may be an ideal cell source for myocardial regenerative medicine. Ghrelin is a gastric‑secreted peptide hormone involved in the multilineage differentiation of MSCs. To the best of our knowledge, however, the role and potential downstream regulatory mechanism of ghrelin in cardiomyocyte differentiation of ADMSCs is still unknown. The mRNA and protein levels were measured by reverse transcription‑quantitative PCR and western blotting. Immunofluorescence staining was used to show the expression and cellular localization of cardiomyocyte markers and β‑catenin. RNA sequencing was used to explore the differentially expressed genes (DEGs) that regulated by ghrelin. The present study found that ghrelin promoted cardiomyocyte differentiation of ADMSCs in a concentration‑dependent manner, as shown by increased levels of cardiomyocyte markers GATA binding protein 4, α‑myosin heavy chain (α‑MHC), ISL LIM homeobox 1, NK2 homeobox 5 and troponin T2, cardiac type. Ghrelin increased β‑catenin accumulation in nucleus and decreased the protein expression of secreted frizzled‑related protein 4 (SFRP4), an inhibitor of Wnt signaling. RNA sequencing was used to determine the DEGs regulated by ghrelin. Functional enrichment showed that DEGs were more enriched in cardiomyocyte differentiation‑associated terms and Wnt pathways. Dead‑box helicase 17 (DDX17), an upregulated DEG, showed enhanced mRNA and protein expression levels following ghrelin addition. Overexpression of DDX17 promoted protein expression of cardiac‑specific markers and β‑catenin and enhanced the fluorescence intensity of α‑MHC and β‑catenin. DDX17 upregulation inhibited protein expression of SFRP4. Rescue assay confirmed that the addition of SFRP4 partially reversed ghrelin‑enhanced protein levels of cardiac‑specific markers and the fluorescence intensity of α‑MHC. In conclusion, ghrelin promoted cardiomyocyte differentiation of ADMSCs by DDX17‑mediated regulation of the SFRP4/Wnt/β‑catenin axis.

Is mesenchymal stem cell effective for allergic rhinitis? A protocol for a systematic review and meta-analysis

INTRODUCTION

Allergic rhinitis (AR) is a kind of widespread but unrecognised inflammatory disorder of nasal mucosa, characterised by itching, sneezing, runny nose and nasal congestion. The efficacy of mesenchymal stem cells (MSCs) in the treatment of AR remains controversial. This protocol describes a systematic review and meta-analysis approach to assess the efficacy and safety of MSCs in the treatment of AR.

METHODS AND ANALYSIS

Eight databases (PubMed, Embase, Cochrane Library, Web of Science, China National Knowledge Infrastructure, Chinese Biomedical Literature Database, VIP and Wanfang) will be searched from the database inception to 1 December 2023. All randomised controlled trials related to MSCs for AR will be included. The primary outcomes will be therapeutic effect, serum IgE index and Visual Analogue Scale score for nasal symptoms. Risk of bias will be assessed using the Cochrane Collaboration's tool for assessing risk of bias. Article selection, data extraction and risk of bias assessment will be performed in duplicate by two independent reviewers.

ETHICS AND DISSEMINATION

Ethics approval is not required because individual patient data are not included. This protocol was registered in the international Prospective Register of Systematic Reviews on 22 January 2022. The systematic review and meta-analysis will be submitted for publication in a peer-reviewed journal. The findings will also be disseminated through conference presentations.

PROSPERO REGISTRATION NUMBER

CRD42022303146.

Safety, immunological effects and clinical response in a phase I trial of umbilical cord mesenchymal stromal cells in patients with treatment refractory SLE

BACKGROUND

Reports of clinical improvement following mesenchymal stromal cell (MSC) infusions in refractory lupus patients at a single centre in China led us to perform an explorative phase I trial of umbilical cord derived MSCs in patients refractory to 6 months of immunosuppressive therapy.

METHODS

Six women with a SLEDAI >6, having failed standard of care therapy, received one intravenous infusion of 1×10⁶ MSCs/kg of body weight. They maintained their current immunosuppressives, but their physician was allowed to adjust corticosteroids initially for symptom management. The clinical endpoint was an SRI of 4 with no new British Isles Lupus Activity Guide (BILAG) As and no increase in Physician Global Assessment score of >0.3 with tapering of prednisone to 10 mg or less by 20 weeks.

RESULTS

Of six patients, five (83.3%; 95% CI 35.9% to 99.6%) achieved the clinical endpoint of an SRI of 4. Adverse events were minimal. Mechanistic studies revealed significant reductions in CD27IgD double negative B cells, switched memory B cells and activated naïve B cells, with increased transitional B cells in the five patients who met the endpoint. There was a trend towards decreased autoantibody levels in specific patients. Two patients had increases in their Helios+Treg cells, but no other significant T cell changes were noted. GARP-TGFβ complexes were significantly increased following the MSC infusions. The B cell changes and the GARP-TGFβ increases significantly correlated with changes in SLEDAI scores.

CONCLUSION

This phase 1 trial suggests that umbilical cord (UC) MSC infusions are very safe and may have efficacy in lupus. The B cell and GARP-TGFβ changes provide novel insight into mechanisms by which MSCs may impact disease.

TRIAL REGISTRATION NUMBER

NCT03171194.

MSC Pretreatment for Improved Transplantation Viability Results in Improved Ventricular Function in Infarcted Hearts

Many clinical studies utilizing MSCs (mesenchymal stem cells, mesenchymal stromal cells, or multipotential stromal cells) are underway in multiple clinical settings; however, the ideal approach to prepare these cells in vitro and to deliver them to injury sites in vivo with maximal effectiveness remains a challenge. Here, pretreating MSCs with agents that block the apoptotic pathways were compared with untreated MSCs. The treatment effects were evaluated in the myocardial infarct setting following direct injection, and physiological parameters were examined at 4 weeks post-infarct in a rat permanent ligation model. The prosurvival treated MSCs were detected in the hearts in greater abundance at 1 week and 4 weeks than the untreated MSCs. The untreated MSCs improved ejection fraction in infarcted hearts from 61% to 77% and the prosurvival treated MSCs further improved ejection fraction to 83% of normal. The untreated MSCs improved fractional shortening in the infarcted heart from 52% to 68%, and the prosurvival treated MSCs further improved fractional shortening to 77% of normal. Further improvements in survival of the MSC dose seems possible. Thus, pretreating MSCs for improved in vivo survival has implications for MSC-based cardiac therapies and in other indications where improved cell survival may improve effectiveness.

In Situ Maturated Early-Stage Human-Induced Pluripotent Stem Cell-Derived Cardiomyocytes Improve Cardiac Function by Enhancing Segmental Contraction in Infarcted Rats

The scant ability of cardiomyocytes to proliferate makes heart regeneration one of the biggest challenges of science. Current therapies do not contemplate heart re-muscularization. In this scenario, stem cell-based approaches have been proposed to overcome this lack of regeneration. We hypothesize that early-stage hiPSC-derived cardiomyocytes (hiPSC-CMs) could enhance the cardiac function of rats after myocardial infarction (MI). Animals were subjected to the permanent occlusion of the left ventricle (LV) anterior descending coronary artery (LAD). Seven days after MI, early-stage hiPSC-CMs were injected intramyocardially. Rats were subjected to echocardiography pre-and post-treatment. Thirty days after the injections were administered, treated rats displayed 6.2% human cardiac grafts, which were characterized molecularly. Left ventricle ejection fraction (LVEF) was improved by 7.8% in cell-injected rats, while placebo controls showed an 18.2% deterioration. Additionally, cell-treated rats displayed a 92% and 56% increase in radial and circumferential strains, respectively. Human cardiac grafts maturate in situ, preserving proliferation with 10% Ki67 and 3% PHH3 positive nuclei. Grafts were perfused by host vasculature with no evidence for immune rejection nor ectopic tissue formations. Our findings support the use of early-stage hiPSC-CMs as an alternative therapy to treat MI. The next steps of preclinical development include efficacy studies in large animals on the path to clinical-grade regenerative therapy targeting human patients.