Cell transplantation for treatment of left-ventricular dysfunction due to ischemic heart failure: from bench to bedside

PD-L1 and AKT Overexpressing Adipose-Derived Mesenchymal Stem Cells Enhance Myocardial Protection by Upregulating CD25+ T Cells in Acute Myocardial Infarction Rat Model

This study explores the synergistic impact of Programmed Death Ligand 1 (PD-L1) and Protein Kinase B (Akt) overexpression in adipose-derived mesenchymal stem cells (AdMSCs) for ameliorating cardiac dysfunction after myocardial infarction (MI). Post-MI adult Wistar rats were allocated into four groups: sham, MI, ADMSC treatment, and ADMSCs overexpressed with PD-L1 and Akt (AdMSC-PDL1-Akt) treatment. MI was induced via left anterior descending coronary artery ligation, followed by intramyocardial AdMSC injections. Over four weeks, cardiac functionality and structural integrity were assessed using pressure-volume analysis, infarct size measurement, and immunohistochemistry. AdMSC-PDL1-Akt exhibited enhanced resistance to reactive oxygen species (ROS) in vitro and ameliorated MI-induced contractile dysfunction in vivo by improving the end-systolic pressure-volume relationship and preload-recruitable stroke work, together with attenuating infarct size. Molecular analyses revealed substantial mitigation in caspase3 and nuclear factor-κB upregulation in MI hearts within the AdMSC-PDL1-Akt group. Mechanistically, AdMSC-PDL1-Akt fostered the differentiation of normal T cells into CD25+ regulatory T cells in vitro, aligning with in vivo upregulation of CD25 in AdMSC-PDL1-Akt-treated rats. Collectively, PD-L1 and Akt overexpression in AdMSCs bolsters resistance to ROS-mediated apoptosis in vitro and enhances myocardial protective efficacy against MI-induced dysfunction, potentially via T-cell modulation, underscoring a promising therapeutic strategy for myocardial ischemic injuries.

Mesenchymal stem cells seeded onto nanofiber scaffold for myocardial regeneration

Cardiac disease is the leading cause of mortality and disability worldwide. We investigated the role of undifferentiated adipose tissue-derived mesenchymal stem cells (ADMSC) alone and ADMSC seeded onto the electro-spun nanofibers (NF) for reconstructing damaged cardiac tissue in isoprenaline-induced myocardial infarction (MI) in rats. ADMSC were sorted by morphological appearance and by detection of cluster of differentiation (CD) surface antigens. The therapeutic potential of ADMSC for treating MI was evaluated by electrocardiogram (ECG), biochemical analysis, molecular genetic analysis and histological examination. Treatment of MI-challenged rats with ADMSC improved ECG findings, which were corroborated by significant decreases in serum lactate dehydrogenase (LDH) and creatine kinase-MB (CK-MB) enzyme activities together with reduced serum troponin T (cTnT) and connexin 43 (Cx43) levels. MI model rats treated with ADMSC exhibited a significant increase in serum alpha sarcomeric actin (Actn) and GATA binding protein 4 (GATA4), and NK2 homeobox 5 (NKX2.5) gene expression was decreased following treatment with ADMSC. ADMSC also ameliorated damage to cardiac tissue. The effects of ADMSC seeded onto NF were superior to those of ADMSC alone. ADMSC may be useful for mitigation of MI.

Stromal vascular fraction technologies and clinical applications

Introduction: The heterogeneous pool of cells found in the stromal vascular fraction of adipose tissue (SVF) and the purified mesenchymal stromal/stem cells (ASCs) isolated from this pool have increasingly been used as therapeutic tools in regenerative medicine.Areas covered: As SVF and ASCs are different, and should be used in different manners according to various clinical and biological indications, we reviewed the current literature, and focused on the clinical use of SVF to appraise the main medical fields for development. Both enzymatic digestion and mechanical disruption have been used to obtain SVF for non-homologous use. The safety and/or benefits of SVF have been examined in 71 clinical studies in various contexts, mainly musculoskeletal conditions, wound healing, urogenital, and cardiovascular and respiratory diseases. The use of SVF as a therapy remains experimental, with few clinical trials.Expert opinion: SVF provides a cellular and molecular microenvironment for regulation of ASC' activities under different clinical conditions. SVF may enhance angiogenesis and neovascularization in wound healing, urogenital and cardiovascular diseases. In joint conditions, therapeutic benefits may rely on paracrine immune-modulatory and anti-inflammatory mechanisms. Novel point of care methods are emerging to refine SVF in ways that meet the regulatory requirements for minimal manipulation.

Direct implantation versus platelet-rich fibrin-embedded adipose-derived mesenchymal stem cells in treating rat acute myocardial infarction

BACKGROUND

This study tested whether adipose-derived mesenchymal stem cells (ADMSC) embedded in platelet-rich fibrin (PRF) scaffold is superior to direct ADMSC implantation in improving left ventricular (LV) performance and reducing LV remodeling in a rat acute myocardial infarction (AMI) model of left anterior descending coronary artery (LAD) ligation.

METHODS

Twenty-eight male adult Sprague Dawley rats equally divided into group 1 [sham control], group 2 (AMI only), group 3 (AMI+direct ADMSC implantation), and group 4 (AMI+PRF-embedded autologous ADMSC) were sacrificed on day 42 after AMI.

RESULTS

LV systolic and diastolic dimensions and volumes, and infarct/fibrotic areas were highest in group 2, lowest in group 1 and significantly higher in group 3 than in group 4, whereas LV performance and LV fractional shortening exhibited a reversed pattern (p<0.005). Protein expressions of inflammation (oxidative stress, IL-1β, MMP-9), apoptosis (mitochondrial Bax, cleaved PARP), fibrosis (Smad3, TGF-β), and pressure-overload biomarkers (BNP, MHC-β) displayed a pattern similar to that of LV dimensions, whereas anti-inflammatory (IL-10), anti-apoptotic (Bcl-2), and anti-fibrotic (Smad1/5, BMP-2) indices showed a pattern similar to that of LV performance among the four groups (all p<0.05). Angiogenesis biomarkers at protein (CXCR4, SDF-1α, VEGF), cellular (CD31+, CXCR4+, SDF-1α+), and immunohistochemical (small vessels) levels, and cardiac stem cell markers (C-kit+, Sca-1+) in infarct myocardium were highest in group 4, lowest in group 1, and significantly higher in group 3 than in group 2 (all p<0.005).

CONCLUSION

PRF-embedded ADMSC is superior to direct ADMSC implantation in preserving LV function and attenuating LV remodeling.

Mid-term effect of stem cells combined with transmyocardial degradable stent on swine model of acute myocardial infarction

BACKGROUND

We aimed to confirm the mid-term results of the new method combined with bone marrow-derived mesenchymal stem cells (MSCs) transplantation and transmyocardial drilling revascularization (TMDR) with degradable stent incorporated with basic fibroblast growth factor and heparin.

METHODS

The miniswine underwent acute myocardial infarction by ligation of the left anterior descending coronary artery. Transmyocardial channels with 3.5 mm diameter (TMDR) were made by mechanical drilling in the infarction territory and basic fibroblast growth factor stents were implanted into the channels. Animals were randomly divided into the following four groups (n=6 in each): control; II: MSCs implantation; III: TMDR+stent implantation; IV: TMDR+stent implantation+MSCs implantation. Three months postoperatively, ECG-gated single photon emission computed tomography, histopathological examination, and reverse transcription-polymerase chain reaction were carried out.

RESULTS

Left ventricular ejection fraction and myocardial perfusion were significantly improved in group IV than that in other groups (P<0.05). Compared with other groups, vessel density was augmented and cell apoptosis was reduced in group IV (P<0.01). Reverse transcription-polymerase chain reaction results showed that the expression levels of von Willebrand factor, transforming growth factor-beta3, vascular endothelial growth factor, and interleukin-1beta were much higher in group IV than that in other groups (P<0.05).

CONCLUSION

Three months after operation, MSCs transplantation combined with TMDR and degradable stent significantly improved cardiac function, enhanced neovascular density, reduced infarcted size, improved ventricular remodeling, and reduced cardiac myocyte apoptosis, and therefore provides strong information for clinical trial.

Global transcriptional analysis for biomarker discovery and validation in cellular therapies

Potency testing is an important part of the evaluation of cellular therapy products. Potency assays are quantitative measures of a product-specific biologic activity that is linked to a relevant biologic property and, ideally, a product's in vivo mechanism of action. Both in vivo and in vitro assays can be used for potency testing. Since there is often a limited period of time between the completion of production and the release from the laboratory for administration to the patient, in vitro assays such as flow cytometry, ELISA, and cytotoxicity are typically used. Better potency assays are needed to assess the complex and multiple functions of cellular therapy products, some of which are not well understood. Gene expression profiling using microarray technology has been widely and effectively used to assess changes of cells in response to stimuli and to classify cancers. Preliminary studies have shown that the expression of non-coding microRNA (miRNA), which plays an important role in cellular development, differentiation, metabolism, and signal transduction, can distinguish between different types of stem cells and leukocytes. Both gene and miRNA expression profiling have the potential to be important tools for testing the potency of cellular therapies. Potency testing, the complexities associated with potency testing of cellular therapies, and the potential role of gene and miRNA expression microarrays in potency testing of cellular therapies are discussed.

Paracrine effects of cell transplantation: modifying ventricular remodeling in the failing heart

Structural ventricular remodeling determines the clinical progression of heart failure and has emerged as an important target for the development of novel medical and surgical therapeutic strategies. Cell transplantation is an innovative biologic therapy that may restore myocardial structure and function in failing hearts. With current forms of cell transplant therapy, true myocardial regeneration has been limited. However, cell transplantation can predictably limit maladaptive ventricular remodeling through multiple synergistic paracrine mechanisms. Some of the paracrine factors released by transplanted cells have been defined. These paracrine signals may provide beneficial effects by stimulating angiogenesis, limiting matrix disruption, and preventing apoptosis. In addition, cell transplantation may induce mobilization and homing of endogenous repair cells to injured myocardium through paracrine signals. Paracrine mediators released from transplanted cells work through multiple, diverse, and interrelated molecular pathways resulting in synergistic effects on the remodeling process. Although true myocardial regeneration remains the ultimate goal of cell therapy, the anti-remodeling abilities of cell transplantation can be harnessed to complement our contemporary surgical approaches for patients with myocardial injury at risk of congestive heart failure.

Allogenic mesenchymal stem cell transplantation has a therapeutic effect in acute myocardial infarction in rats

The goal of the study was to examine if allogenic mesenchymal stem cell (MSC) transplantation is a useful therapy for acute myocardial infarction (AMI). Buffer (control; group C, n=41), MSCs of male ACI rats (allogenic; group A, n=38, 5 x 10(6)), or MSCs of male LEW rats (syngenic; group S, n=40, 5 x 10(6)) were injected into the scar 15 min after myocardial infarction in female LEW rats. After 28 days, fractional left ventricular shortening significantly increased in groups A (21.3+/-1.7%, P=0.0467) and S (23.2+/-1.9%, P=0.0140), compared to group C (17.1+/-0.9%). Fibrosis in groups A and S was significantly lower. Quantitative PCR of the male-specific sry gene showed disappearance of donor cells within 28 days (5195+/-1975 cells). Secretion of vascular endothelial growth factor (VEGF) by MSCs was enhanced under hypoxic conditions in vitro. In groups A and S, the plasma VEGF concentration, VEGF level, and capillary density in recipient hearts increased after 28 days. Flow cytometry revealed the absence of B7 signal molecules on MSCs. A mixed lymphocyte reaction showed that ACI MSCs failed to stimulate proliferation of LEW lymphocytes. After 1 day after cell transplantation, transient increases in interleukin-1 beta and monocyte chemoattractant protein-1 in recipient hearts were enhanced in group A, with macrophage infiltration at the injection site. T cells remained at the level of normal tissue in all groups. We conclude that allogenic MSC transplantation therapy is useful for AMI. The donor MSCs disappear rapidly, but become a trigger of VEGF paracrine effect, without induction of immune rejection.

Potency analysis of cellular therapies: the emerging role of molecular assays

Potency testing is an important part of the evaluation of cellular therapy products. Potency assays are quantitative measures of a product-specific biological activity that is linked to a relevant biological property and, ideally, a product's in vivo mechanism of action. Both in vivo and in vitro assays can be used for potency testing. Since there is often a limited period of time between the completion of production and the release from the laboratory for administration to the patient, in vitro assays such are flow cytometry, ELISA, and cytotoxicity are typically used. Better potency assays are needed to assess the complex and multiple functions of cellular therapy products, some of which are not well understood. Gene expression profiling using microarray technology has been widely and effectively used to assess changes of cells in response to stimuli and to classify cancers. Preliminary studies have shown that the expression of noncoding microRNA which play an important role in cellular development, differentiation, metabolism and signal transduction can distinguish different types of stem cells and leukocytes. Both gene and microRNA expression profiling have the potential to be important tools for testing the potency of cellular therapies. Potency testing, the complexities associated with potency testing of cellular therapies, and the potential role of gene and microRNA expression microarrays in potency testing of cellular therapies is discussed.