Combined therapy with human cord blood cell transplantation and basic fibroblast growth factor delivery for treatment of myocardial infarction

Biomimetic electrical stimulation induces rat bone marrow mesenchymal stem cells to differentiate into cardiomyocyte-like cells via TGF-beta 1 in vitro

Electrical conductance is one of the factors of the microenvironment of cardiomyocytes, and electrical stimulation (ES) has been shown to modulate the differentiation of bone marrow-derived mesenchymal stem cells (BMSCs) toward a cardiomyogenic fate. Transforming growth factor-beta 1 (TGF-β1) stimulates the cardiomyogenic marker expression in BMSCs. Herein, we promoted the differentiation of BMSCs into cardiomyocyte-like cells using ES to confirm if TGF-β1 mediates this event in vitro. ES increased protein levels of TGF-β1 in BMSCs, and this effect was better than that observed with 5-azacytidine (5-Aza). The effect of ES on promoting cardiomyogenic marker expression in BMSCs was enhanced by TGF-β1. Furthermore, the protein expression levels of Connexin43 (Cx43) and Alpha-actinin 2 (ACTN2) induced by ES in BMSCs were significantly decreased by pirfenidone. These results show that ES promotes cardiomyocyte-like cells differentiation in rat BMSCs and is possibly mediated by TGF-β1 in vitro.

Alginate–marine collagen–agarose composite hydrogels as matrices for biomimetic 3D cell spheroid formation

We report a novel, customizable, transparent, biocompatible, functional, easy-to-produce, efficient and cost-effective AmCA scaffold for 3D cell culture.

Janus-like role of fibroblast growth factor 2 in arteriosclerotic coronary artery disease: atherogenesis and angiogenesis

Angiogenic stimulation is a promising new strategy for treating patients with arteriosclerotic coronary artery disease. This strategy aims to ameliorate cardiac function by improving myocardial perfusion and lowering the risk of myocardial infarction. However, angiogenesis may contribute to the growth of atherosclerotic lesions. Atherogenesis is also a potential side effect of angiogenic therapy. Early clinical trials were performed using fibroblast growth factor 2 (FGF2) protein, which enhances the formation of new collateral vessels to reduce ischaemic symptoms. Conversely, angiogenic stimulation by FGF2 is a dilemma because it could cause negative angiogenic effects, such as atherosclerosis. Thus far, clinical trials in patients with recombinant FGF2 protein therapy have not yet yielded undisputable beneficial effects. Future trials should determine whether an improvement can be obtained in patients with coronary artery disease using a combination of FGF2 and other growth factors or a combination of the FGF2 gene and stem cell therapy. This review summarises the multiple roles of FGF2 in the progression of atherosclerosis, its effect on pro-angiogenesis and improvement of cardiac function in coronary artery disease, and the potentially unfavourable effect of angiogenesis on the prevention and treatment of atherogenesis.

Transplantation of cord blood mesenchymal stem cells as spheroids enhances vascularization

Despite promising results from the therapeutic use of stem cells for treating ischemic diseases, the poor survival of cells transplanted into ischemic regions is one of the major problems that undermine the efficacy of stem cell therapy. Cord blood mononuclear cells (CBMNCs) are an alternative source of mesenchymal stem cells (MSCs) without disadvantages, such as the painful and invasive harvesting procedure, of MSCs derived from bone marrow or adipose tissue. In the present study, we investigated whether the angiogenic efficacy of cord blood mesenchymal stem cells (CBMSCs) can be enhanced by grafting as spheroids in a mouse hindlimb ischemia model. Human CBMSC (hCBMSC) spheroids were prepared by using the hanging-drop method. Mouse hindlimb ischemia was induced by excising the femoral artery and its branches. After surgery, the animals were divided into no-treatment, dissociated hCBMSC, and spheroid hCBMSC groups (n=8 per group) and received corresponding hCBMSC treatments. After surgery, the ischemic hindlimbs were monitored for 4 weeks, and then, the ischemic hindlimb muscles were harvested for histological analysis. Apoptotic signaling, angiogenesis-related signal pathways, and blood vessel formation were investigated in vitro and/or in vivo. The transplantation of hCBMSCs as spheroids into mouse ischemic hindlimbs significantly improved the survival of the transplanted cells by suppressing apoptotic signaling while activating antiapoptotic signaling. Furthermore, the transplantation of hCBMSCs as spheroids significantly increased the number of microvessels and smooth muscle α-actin-positive vessels in the ischemic limbs of mice, and attenuated limb loss and necrosis. Human CBMNC can be considered an alternative source of MSC, and spheroid-based hCBMSC delivery can be considered a simple and effective strategy for enhancing the therapeutic efficacy of hCBMSCs.

Comparison of Various Niches for Endothelial Progenitor Cell Therapy on Ischemic Myocardial Repair

Objective—

Comparative studies are lacking that show the effects of different microenvironments on the activity of engrafted stem cells after myocardial infarction (MI). Here, we analyzed the temporal and spatial variations of angiogenesis, collateralization, and the expression of Akt-related signals after MI to test whether the effects of endothelial progenitor cells (EPCs) were different.

Methods and Results—

After the induction of MI, pigs were selected that did not develop a collateral coronary circulation (R0) or developed a significant collateral coronary circulation (R2). Both sets were allocated randomly to 4 groups: phosphate-buffered saline (intramyocardial injection of phosphate-buffered saline), EPC transplantation, LY294002 (intramyocardial injection of an Akt inhibitor), and EPCs plus LY294002. Infarcted porcine hearts at different time points and under different collateralized conditions exhibited a variety of vascular microenvironments. At 14 days post-MI, angiogenesis and the expression of Akt-mediated angiogenic cytokines predominated in R2 porcine hearts. When grafted into this microenvironment, EPCs induced the greatest effects in impeding the development of heart failure, preserving left ventricular function and dimensions, and inhibiting infarct expansion. LY294002 significantly reduced these effects.

Conclusion—

These findings suggest that the microenvironment that coexists with collateralization and Akt-mediated angiogenesis appears to be more beneficial to cardiac repair induced by EPC therapy than other niches after MI.

Using polymeric materials to control stem cell behavior for tissue regeneration

Patients with organ failure often suffer from increased morbidity and decreased quality of life. Current strategies of treating organ failure have limitations, including shortage of donor organs, low efficiency of grafts, and immunological problems. Tissue engineering emerged about two decades ago as a strategy to restore organ function with a living, functional engineered substitute. However, the ability to engineer a functional organ is limited by a limited understanding of the interactions between materials and cells that are required to yield functional tissue equivalents. Polymeric materials are one of the most promising classes of materials for use in tissue engineering, due to their biodegradability, flexibility in processing and property design, and the potential to use polymer properties to control cell function. Stem cells offer potential in tissue engineering because of their unique capacity to self-renew and differentiate into neurogenic, osteogenic, chondrogenic, and myogenic lineages under appropriate stimuli from extracellular components. This review examines recent advances in stem cell-polymer interactions for tissue regeneration, specifically highlighting control of polymer properties to direct adhesion, proliferation, and differentiation of stem cells, and how biomaterials can be designed to provide some of the stimuli to cells that the natural extracellular matrix does.

Myocardial regeneration: Roles of stem cells and hydrogels

Heart failure remains the leading cause of morbidity and mortality. Recently, it was reported that the adult heart has intrinsic regenerative capabilities, prompting a great wave of research into applying cell-based therapies, especially with skeletal myoblasts and bone marrow-derived cells, to regenerate heart tissues. While the mechanism of action for the observed beneficial effects of bone marrow-derived cells remains unclear, new cell candidates are emerging, including embryonic stem (ES) and introduced pluripotent stem (iPS) cells, as well as cardiac stem cells (CSCs) from adult hearts. However, the very low engraftment efficiency and survival of implanted cells prevent cell therapy from turning into a clinical reality. Injectable hydrogel biomaterials based on hydrophilic, biocompatible polymers and peptides have great potential for addressing many of these issues by serving as cell/drug delivery vehicles and as a platform for cardiac tissue engineering. In this review, we will discuss the application of stem cells and hydrogels in myocardial regeneration.

In vitro cardiomyogenic differentiation of adipose-derived stromal cells using transforming growth factor-beta1

Transplanting stem cells differentiated towards a cardiac lineage can regenerate cardiac muscle tissues to treat myocardial infarction. In this study, we tested the hypothesis that transforming growth factor-beta1 (TGF-beta1) induces cardiomyogenic differentiation of adipose- derived stromal cells (ADSCs) in vitro. Rat ADSCs were cultured with TGF-beta1 (10 ng ml(-1)) for 2 weeks in vitro. ADSCs cultured without TGF-beta1 served as a control. The mRNA expression of cardiac-specific gene was induced by TGF-beta1, while the control culture did not show cardiac-specific gene expression. Immunocytochemical analyses showed that a small fraction of ADSCs cultured with TGF-beta1 for 2 weeks stained positively for cardiac myosin heavy chain (MHC) and alpha-sarcomeric actin. Flow cytometric analyses showed that the proportion of cells expressing cardiac MHC increased with TGF-beta1. However, no mesenchymal differentiation (e.g., osteogenic and adipogenic differentiation) was detected other than cardiomyogenic differentiation. These results showed that TGF-beta1 induce ADSC cardiomyogenic differentiation in vitro, which could be useful for myocardial infarction stem cell therapy.

Myocardial repair: from salvage to tissue reconstruction

Cardiac tissue reconstruction following myocardial infarction represents a major challenge in cardiovascular therapy, as current clinical approaches are limited in their ability to regenerate or replace damaged myocardium. Thus, different novel treatments have been introduced aimed at myocardial salvage and repair. Here, we present a review of recent advancements in cardiac cell, gene-based and tissue engineering therapies. Selected strategies in cell therapy and new tools for myocardial gene transfer are summarized. Finally, we consider novel approaches to myocardial tissue engineering as a platform for the integration of various modalities in an attempt to rejuvenate infarcted tissue in vivo.