Addition of mesenchymal stem cells enhances the therapeutic effects of skeletal myoblast cell-sheet transplantation in a rat ischemic cardiomyopathy model

The fate of adipose tissue and adipose-derived stem cells in allograft

Utilizing adipose tissue and adipose-derived stem cells (ADSCs) turned into a promising field of allograft in recent years. The therapeutic potential of adipose tissue and ADSCs is governed by their molecular secretions, ability to sustain multi-differentiation and self-renewal which are pivotal in reconstructive, genetic diseases, and cosmetic goals. However, revisiting the existing functional capacity of adipose tissue and ADSCs and their intricate relationship with allograft is crucial to figure out the remarkable question of safety to use in allograft due to the growing evidence of interactions between tumor microenvironment and ADSCs. For instance, the molecular secretions of adipose tissue and ADSCs induce angiogenesis, create growth factors, and control the inflammatory response; it has now been well determined. Though the existing preclinical allograft studies gave positive feedback, ADSCs and adipose tissue are attracted by some factors of tumor stroma. Moreover, allorecognition is pivotal to allograft rejection which is carried out by costimulation in a complement-dependent way and leads to the destruction of the donor cells. However, extensive preclinical trials of adipose tissue and ADSCs in allograft at molecular level are still limited. Hence, comprehensive immunomodulatory analysis could ensure the successful allograft of adipose tissue and ADSCs avoiding the oncological risk.

Angiogenic stem cell delivery platform to augment post-infarction neovasculature and reverse ventricular remodeling

Many cell-based therapies are challenged by the poor localization of introduced cells and the use of biomaterial scaffolds with questionable biocompatibility or bio-functionality. Endothelial progenitor cells (EPCs), a popular cell type used in cell-based therapies due to their robust angiogenic potential, are limited in their therapeutic capacity to develop into mature vasculature. Here, we demonstrate a joint delivery of human-derived endothelial progenitor cells (EPC) and smooth muscle cells (SMC) as a scaffold-free, bi-level cell sheet platform to improve ventricular remodeling and function in an athymic rat model of myocardial infarction. The transplanted bi-level cell sheet on the ischemic heart provides a biomimetic microenvironment and improved cell-cell communication, enhancing cell engraftment and angiogenesis, thereby improving ventricular remodeling. Notably, the increased density of vessel-like structures and upregulation of biological adhesion and vasculature developmental genes, such as Cxcl12 and Notch3, particularly in the ischemic border zone myocardium, were observed following cell sheet transplantation. We provide compelling evidence that this SMC-EPC bi-level cell sheet construct can be a promising therapy to repair ischemic cardiomyopathy.

Electrospun Fiber-Coated Human Amniotic Membrane: A Potential Angioinductive Scaffold for Ischemic Tissue Repair

Cardiac patch implantation helps maximize the paracrine function of grafted cells and serves as a reservoir of soluble proangiogenic factors required for the neovascularization of infarcted hearts. We have previously fabricated a cardiac patch, EF-HAM, composed of a human amniotic membrane (HAM) coated with aligned PLGA electrospun fibers (EF). In this study, we aimed to evaluate the biocompatibility and angiogenic effects of EF-HAM scaffolds with varying fiber thicknesses on the paracrine behavior of skeletal muscle cells (SkM). Conditioned media (CM) obtained from SkM-seeded HAM and EF-HAM scaffolds were subjected to multiplex analysis of angiogenic factors and tested on HUVECs for endothelial cell viability, migration, and tube formation analyses. All three different groups of EF-HAM scaffolds demonstrated excellent biocompatibility with SkM. CM derived from SkM-seeded EF-HAM 7 min scaffolds contained significantly elevated levels of proangiogenic factors, including angiopoietin-1, IL-8, and VEGF-C compared to plain CM, which was obtained from SkM cultured on the plain surface. CM obtained from all SkM-seeded EF-HAM scaffolds significantly increased the viability of HUVECs compared to plain CM after five days of culture. However, only EF-HAM 7 min CM induced a higher migration capacity in HUVECs and formed a longer and more elaborate capillary-like network on Matrigel compared with plain CM. Surface roughness and wettability of EF-HAM 7 min scaffolds might have influenced the proportion of skeletal myoblasts and fibroblasts growing on the scaffolds and subsequently potentiated the angiogenic paracrine function of SkM. This study demonstrated the angioinductive properties of EF-HAM composite scaffold and its potential applications in the repair and regeneration of ischemic tissues.

Adipose Tissue-Derived Mesenchymal Stem Cells

The long-held belief about adipose tissue was that it was relatively inert in terms of biological activity. It was believed that its primary role was energy storage; however, that was shattered with the discovery of adipokines. Scientists interested in regenerative medicine then reported that adipose tissue is rich in adult stromal/stem cells. Following these initial reports, adipose stem cells (ASCs) rapidly garnered interest for use as potential cellular therapies. The primary advantages of ASCs compared to other mesenchymal stem cells (MSCs) include the abundance of the tissue source for isolation, the ease of methodologies for tissue collection and cell isolation, and their therapeutic potential. Studies conducted both in vitro and in vivo have demonstrated that ASCs are multipotent, possessing the ability to differentiate into cells of mesodermal origins, including adipocytes, chondrocytes, osteoblast and others. Moreover, ASCs produce a broad array of cytokines, growth factors, nucleic acids (miRNAs), and other macromolecules into the surrounding milieu by secretion or in the context of microvesicles. The secretome of ASCs has been shown to alter tissue biology, stimulate tissue-resident stem cells, change immune cell activity, and mediate therapeutic outcomes. The quality of ASCs is subject to donor-to-donor variation driven by age, body mass index, disease status and possibly gender and ethnicity. This review discusses adipose stromal/stem cell action mechanisms and their potential utility as cellular therapeutics.

3D bioprinting of stem cell-laden cardiac patch: A promising alternative for myocardial repair

Stem cell-laden three-dimensional (3D) bioprinted cardiac patches offer an alternative and promising therapeutic and regenerative approach for ischemic cardiomyopathy by reversing scar formation and promoting myocardial regeneration. Numerous studies have reported using either multipotent or pluripotent stem cells or their combination for 3D bioprinting of a cardiac patch with the sole aim of restoring cardiac function by faithfully rejuvenating the cardiomyocytes and associated vasculatures that are lost to myocardial infarction. While many studies have demonstrated success in mimicking cardiomyocytes' behavior, improving cardiac function and providing new hope for regenerating heart post-myocardial infarction, some others have reported contradicting data in apparent ways. Nonetheless, all investigators in the field are speed racing toward determining a potential strategy to effectively treat losses due to myocardial infarction. This review discusses various types of candidate stem cells that possess cardiac regenerative potential, elucidating their applications and limitations. We also brief the challenges of and an update on the implementation of the state-of-the-art 3D bioprinting approach to fabricate cardiac patches and highlight different strategies to implement vascularization and augment cardiac functional properties with respect to electrophysiological similarities to native tissue.

Three-Dimensional Multilayered Microstructure Using Needle Array Bioprinting System

Tissue engineering is an essential component of developing effective regenerative therapies. In this study, we introduce a promising method to create scaffold-free three-dimensional (3D) tissue engineered multilayered microstructures from cultured cells using the "3D tissue fabrication system" (Regenova^®; Cyfuse, Tokyo, Japan). This technique utilizes the adhesive nature of cells. When cells are cultured in nonadhesive wells, they tend to aggregate and form a spheroidal structure. The advantage of this approach is that cellular components can be mixed into one spheroid, thereby promoting the formation of extracellular matrices, such as collagen and elastin. This system enables one to create a predesigned 3D structure composed of cultured cells. We found that the advantages of this system to be (1) the length, size, and shape of the structure that were designable and highly reproducible because of the computer controlled robotics system, (2) the graftable structure could be created within a reasonable period (8 days), and (3) the constructed tissue did not contain any foreign material, which may avoid the potential issues of contamination, biotoxicity, and allergy. The utilization of this robotic system enabled the creation of a 3D multilayered microstructure made of cell-based spheres with a satisfactory mechanical properties and abundant extracellular matrix during a short period of time. These results suggest that this new technology will represent a promising, attractive, and practical strategy in the field of tissue engineering. Impact statement The utilization of the "three dimensional tissue fabrication system" enabled the creation of a three-dimensional (3D) multilayered microstructure made of cell-based spheres with a satisfactory mechanical properties and abundant extracellular matrix during a short period of time. These results suggest that this new technology will represent a promising, attractive, and practical strategy in the field of tissue engineering.

Current Status and Limitations of Myocardial Infarction Large Animal Models in Cardiovascular Translational Research

Establishing an appropriate disease model that mimics the complexities of human cardiovascular disease is critical for evaluating the clinical efficacy and translation success. The multifaceted and complex nature of human ischemic heart disease is difficult to recapitulate in animal models. This difficulty is often compounded by the methodological biases introduced in animal studies. Considerable variations across animal species, modifications made in surgical procedures, and inadequate randomization, sample size calculation, blinding, and heterogeneity of animal models used often produce preclinical cardiovascular research that looks promising but is irreproducible and not translatable. Moreover, many published papers are not transparent enough for other investigators to verify the feasibility of the studies and the therapeutics' efficacy. Unfortunately, successful translation of these innovative therapies in such a closed and biased research is difficult. This review discusses some challenges in current preclinical myocardial infarction research, focusing on the following three major inhibitors for its successful translation: Inappropriate disease model, frequent modifications to surgical procedures, and insufficient reporting transparency.

Autologous transplantation of multilayered fibroblast sheets prevents postoperative pancreatic fistula by regulating fibrosis and angiogenesis

INTRODUCTION

Postoperative pancreatic fistula (POPF) is a serious complication after gastrointestinal or pancreatic surgery. Despite intensive investigations, the occurrence has not significantly decreased in the past decades. The aims of this study were to clarify the pathophysiology of POPF and establish the preventive measures using multilayered fibroblast sheets.

METHODS

We developed a pancreatic fistula (PF) model of rat with transection of the splenic duct and surrounding pancreatic parenchyma. Multilayered fibroblast sheets prepared from tails were autologously transplanted to this model. The preventive effect was biochemically and histologically evaluated by measuring the ascitic levels of pancreatic enzymes and conducting immunohistochemistry and real-time polymerase chain reaction analyses of pancreatic tissue. Findings were compared to those obtained with acellular materials simply sealing the wound.

RESULTS

In the PF model, the ascitic levels of pancreatic enzymes were transiently up-regulated. Inflammation and necrosis were histologically observed in a wide range. Islets were damaged even in remote areas. Transplantation of multilayered fibroblast sheets dramatically reduced the ascitic leakage of enzymes, suppressed inflammation, and broadly preserved the islets. Compared with acellular materials, these sheets offered superior prevention of cellular activity through the spaciotemporal regulation of fibrosis and angiogenesis. Notably, the leakage hole appeared to have been plugged with the fibrotic matrix, which might have been the most crucial mechanism minimizing pancreatic damage.

CONCLUSIONS

The autologous transplantation of multilayered fibroblast sheets significantly prevented PF and protected the pancreas, underscoring the potential utility of this approach for POPF prevention.

Long-term outcomes of autologous skeletal myoblast cell-sheet transplantation for end-stage ischemic cardiomyopathy

We evaluated the cardiac function recovery following skeletal myoblast cell-sheet transplantation and the long-term outcomes after applying this treatment in 23 patients with ischemic cardiomyopathy. We defined patients as “responders” when their left ventricular ejection fraction remained unchanged or improved at 6 months after treatment. At 6 months, 16 (69.6%) patients were defined as responders, and the average increase in left ventricular ejection fraction was 4.9%. The responders achieved greater improvement degrees in left ventricular and hemodynamic function parameters, and they presented improved exercise capacity. During the follow-up period (56 ± 28 months), there were four deaths and the overall 5-year survival rate was 95%. Although the responders showed higher freedom from mortality and/or heart failure admission (5-year, 81% versus 0%; p = 0.0002), both groups presented an excellent 5-year survival rate (5-year, 93% versus 100%; p = 0.297) that was higher than that predicted using the Seattle Heart Failure Model. The stepwise logistic regression analysis showed that the preoperative estimated glomerular filtration rate and the left ventricular end-systolic volume index were independently associated with the recovery progress. Approximately 70% of patients with “no-option” ischemic cardiomyopathy responded well to the cell-sheet transplantation. Preoperative renal and left ventricular function might predict the patients’ response to this treatment.

Multilayered Human Skeletal Muscle Myoblast Sheets Promote the Healing Process After Colonic Anastomosis in Rats

Colorectal anastomotic leakage is one of the most feared and fatal complications of colorectal surgery. To date, no external coating material that can prevent anastomotic leakage has been developed. As myoblasts possess anti-inflammatory capacity and improve wound healing, we developed a multilayered human skeletal muscle myoblast (HSMM) sheet by periodic exposure to supraphysiological hydrostatic pressure during repeated cell seeding. We assessed whether the application of an HSMM sheet can promote the healing process after colonic anastomosis. Partial colectomy and insufficient suturing were employed to create a high-risk colo-colonic anastomosis model in 60 nude rats. Rats were divided into a control group (n = 30) and an HSMM sheet group (n = 30). Macroscopic findings, anastomotic bursting pressure, and histology at the colonic anastomotic site were evaluated on postoperative day (POD) 3, 5, 7, 14, and 28. The application of an HSMM sheet significantly suppressed abscess formation at the anastomotic site compared to the control group on POD3 and 5. The anastomotic bursting pressure in the HSMM sheet group was higher than that in the control group on POD3 and 5. Inflammatory cell infiltration in the HSMM sheet group was significantly suppressed compared to that in the control group throughout the time course. Collagen deposition in the HSMM sheet group on POD3 was significantly abundant compared to that in the control group. Regeneration of the mucosa at the colonic anastomotic site was promoted in the HSMM sheet group compared to that in the control group on POD14 and 28. Immunohistochemical analysis demonstrated that surviving cells in the HSMM sheet gradually decreased with postoperative time and none were detected on POD14. These results suggest that the application of a multilayered HSMM sheet may prevent postoperative colonic anastomotic leakage.

Cell biobank as a necessary infrastructure for the development and implementation of mesenchymal stem cell-based therapy in the treatment of anthracycline-induced cardiotoxicity. Literature review and own data

Cardiovascular diseases, along with cancer, are the leading causes of death worldwide. Although modern pharmacological treatment of various cardiomyopathies can slow the development of myocardial dysfunction, they have limited effectiveness in patients with end-stage disease. Many researchers believe that heart transplantation is the only radical treatment in this case. However, the lack of donors and the high 

operation cost require careful selection of surgical candidates. With the introduction of molecular and cell biology into medical practice, today, stem cell therapy can become an alternative method of nonsurgical restoration of myocardial functions. The most studied and attractive is the use of mesenchymal stem cells (MSCs). MSCs differ from hematopoietic stem cells used as support for hematopoiesis in high-dose chemotherapy by the following features: pronounced trophic effect, immune tolerance, the ability to suppress alloreactivity and autoimmune disorders. An important stage in the implementation of cell therapy is the creation of a cell biobank of MSCs. In A.F.Tsyb Medical Radiological Research Center, this work has been carried out since1984. Asignificant number of experimental studies have been carried out, confirming the possibility of clinical implementation of this approach. A method for obtaining stable cultures of MSCs and cardiomyoblasts from bone marrow cells was developed and approvals were obtained. Experimental studies of cell therapy are also being conducted to overcome anthracycline-induced cardiotoxicity in cancer patients.

This article is devoted to practical application of MSC-based therapy, in particular, in cancer patients with cardiotoxicity, as well as to the issues of creating a cell biobank for treatment with MSCs.

Collagen-Supplemented Incubation Rapidly Augments Mechanical Property of Fibroblast Cell Sheets

Cell sheet technology using UpCell™ (Thermo Fisher Scientific, Roskilde, Denmark) plates is a modern tool that enables the rapid creation of single-layered cells without using extracellular matrix (ECM) enzymatic digestion. Although this technique has the advantage of maintaining a sheet of cells without needing artificial scaffolds, these cell sheets remain extremely fragile. Collagen, the most abundant ECM component, is an attractive candidate for modulating tissue mechanical properties given its tunable property. In this study, we demonstrated rapid mechanical property augmentation of human dermal fibroblast cell sheets after incubation with bovine type I collagen for 24 h on UpCell plates. We showed that treatment with collagen resulted in increased collagen I incorporation within the cell sheet without affecting cell morphology, cell type, or cell sheet quality. Atomic force microscopy measurements for controls, and cell sheets that received 50 and 100 μg/mL collagen I treatments revealed an average Young's modulus of their respective intercellular regions: 6.6 ± 1.0, 14.4 ± 6.6, and 19.8 ± 3.8 kPa during the loading condition, and 10.3 ± 4.7, 11.7 ± 2.2, and 18.1 ± 3.4 kPa during the unloading condition. This methodology of rapid mechanical property augmentation of a cell sheet has a potential impact on cell sheet technology by improving the ease of construct manipulation, enabling new translational tissue engineering applications.

Role and therapeutic effects of skeletal muscle-derived non-myogenic cells in a rat myocardial infarction model

Background

Transplantation of skeletal myoblast sheets is a promising strategy for the treatment of heart failure, and its therapeutic effects have already been proven in both animal disease models and clinical trials. Myoblast sheets reportedly demonstrate their therapeutic effects by producing many paracrine factors. Although the quality of processed cells for transplantation can be evaluated by the positive ratio of CD56, a myoblast marker, it is unclear which cell populations from isolated cells produce paracrine factors that have an impact on therapeutic effects, and whether these therapeutic effects are closely correlated with CD56-positive cells isolated from the skeletal muscle is also unclear. Therefore, we hypothesized that CD56-negative cells as well as CD56-positive cells isolated from the skeletal muscle produce paracrine factors and have therapeutic effects in skeletal muscle-derived cell sheet therapy for heart failure.

Methods

Cell surface and intracellular markers of CD56-negative non-myogenic cells (NMCs) and CD56-positive myoblasts were evaluated. We also analyzed cytokine expression, tube formation ability, and stem cell mobilization in both cell populations. Finally, we assessed the therapeutic effects of the cell populations in a rat myocardial infarction model.

Results

Analysis of cell surface and intracellular markers revealed that CD56-negative NMCs expressed fibroblast markers and a higher level of mesenchymal cell markers, such as CD49b and CD140a, than myoblasts. Both NMCs and myoblasts expressed various cytokines in vitro with different expression patterns. In addition, NMCs induced tube formation (control vs. myoblasts vs. NMCs: 100 ± 11.2 vs. 142 ± 8.3 vs. 198 ± 7.4%) and stem cell mobilization (control vs. myoblasts vs. NMCs: 100 ± 6.8 vs. 210 ± 22.9 vs. 351 ± 36.0%) to a higher degree in vitro than did myoblasts. The effect of NMCs and myoblasts on the improvement of cardiac function and suppression of myocardial fibrosis in rat myocardial infarction model was comparable.

Conclusion

These results indicate that NMCs exhibit therapeutic effects in skeletal muscle-derived cell sheet therapy for heart failure. Thus, accurate parameters correlating with therapeutic effects need to be further explored.

[Construction of three-dimensional dermoid tissue based on cell sheets technology in vitro]

Objective

To explore a new strategy for constructing three-dimensional dermoid tissue in vitro by using cell sheets technology.

Methods

Rabbit bone marrow mesenchymal stem cells (rBMSCs) were isolated from bone marrow of New Zealand white rabbits and cultured by whole bone marrow adherent method. Human dermal fibroblasts (HDFs) were cultured and passaged in vitro. The 2nd generation rBMSCs and the 3rd generation HDFs were cultured in a culture dish for 2 weeks with cell sheets conditioned medium respectively to obtain a monolayer cell sheets. Human umbilical vein endothelial cells (HUVECs) were inoculated on rBMSCs sheet to construct pre-vascularized cell sheet. During the culture period, the morphological changes of the cell sheet were observed under an inverted phase contrast microscope. At 1, 3, 7, and 14 days, HE staining and CD31 immunofluorescence staining were performed to observe the cell distribution and microvascular network formation. The rBMSCs sheet was used as control. The pre-vascularized cell sheet (experimental group) and rBMSCs sheet (control group) cultured for 7 days were placed in the middle of two HDFs sheets, respectively, to prepare three-dimensional dermoid tissues. After 24 hours of culture, CD31 immunofluorescence staining and collagen type Ⅰ and collagen type Ⅲ immunohistochemical stainings were performed to evaluate cell distribution and collagen expression.

Results

HDFs and rBMSCs sheets were successfully prepared after 2 weeks of cell culture. After inoculation of HUVECs on rBMSCs sheet for 3 days, HUVECs could be seen to rearrange on rBMSCs sheet and forming vacuoles. The reticular structure was visible at 7 days and more obvious at 14 days. The formation of vacuoles between the cell sheets was observed by HE staining, and the vacuoles became more and more obvious, the thickness of the membranes increased significantly with time. CD31 immunofluorescence staining showed the microvascular lumen formation. However, only the thickness of rBMSCs sheet increasing was observed, with no changes in cell morphology or cavitation structure. The three-dimensional dermoid tissue observation showed that the endothelial cells in the experimental group were positive expressions, and the rBMSCs, HDFs, and HUVECs cells were arranged neatly. The endothelial cells were negative expressions and randomly arranged in the control group. The collagen type Ⅰ and collagen type Ⅲ were positive expression in the experimental group and the control group. But compared with control group, experimental group presented a "honeycomb" network connection, where the matrix was distributed regularly, and cells were arranged tightly. The difference in the expression of collagen type Ⅰ and collagen type Ⅲ between the experimental group and the control group was not significant ( P>0.05).

Conclusion

Three-dimensional dermoid tissue is successfully constructed by using cell sheet technology. The cell matrix distribution of the pre-vascularized cell sheet constructed by HUVECs and rBMSCs sheet is relatively regular, which has the potential to form tissue engineered dermis.

Transplanted human multipotent stromal cells reduce acute tongue fibrosis in rats

Background

Tongue fibrosis resulting from head and neck cancer, surgery, radiation, chemotherapy, or a combination thereof devastates one's quality of life. Therapeutic options are limited. Here we investigate human bone marrow-derived multipotent stromal cells (MSC) as a novel injectable treatment for post-injury tongue fibrosis.

Methods

MSCs were grown in culture. Eighteen athymic rats underwent unilateral partial glossectomy. After two weeks for scar formation, a single injection was performed in the tongue scar. Three treatment groups were studied: low and high concentration MSC, and control media injection. Tongues were harvested for evaluation at three weeks post-treatment.

Results

Dense fibrosis was achieved in control animals at five weeks. High concentration MSC reduced cross sectional scar burden (P = .007) and pathologic score for inflammation and fibrosis.

Conclusion

This study establishes the feasibility of a novel rodent tongue fibrosis model, and begins to assess the utility of human MSCs to reduce scar burden.

Level of Evidence

N/a.

Maturation of Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes by Soluble Factors from Human Mesenchymal Stem Cells

In this study, we proposed that the functionality or phenotype of differentiated cardiomyocytes derived from human induced pluripotent stem cells (iPSC-CMs) might be modified by co-culture with mesenchymal stem cells (MSCs), resulting in an improved therapeutic potential for failing myocardial tissues. Structural, motility, electrophysiological, and metabolic analyses revealed that iPSC-CMs co-cultured with MSCs displayed aligned myofibrils with A-, H-, and I-bands that could contract and relax quickly, indicating the promotion of differentiation and the establishment of the iPSC-CM structural framework, and showed clear gap junctions and an electric pacing of >2 Hz, indicating enhanced cell-cell interactions. In addition, soluble factors excreted by MSCs, including several cytokines and exosomes, enhanced cardiomyocyte-specific marker production, produced more energy under normal and stressed conditions, and reduced reactive oxygen species production by iPSC-CMs under stressed condition. Notably, gene ontology and pathway analysis revealed that microRNAs and proteins in the exosomes impacted the functionality and maturation of iPSC-CMs. Furthermore, cell sheets consisting of a mixture of iPSC-CMs and MSCs showed longer survival and enhanced therapeutic effects compared with those consisting of iPSC-CMs alone. This may lead to a new type of iPSC-based cardiomyogenesis therapy for patients with heart failure.

Transplantation of Adipose Tissue-Derived Stem Cell Sheet to Reduce Leakage After Partial Colectomy in A Rat Model

Anastomotic leakage is a disastrous complication after colorectal surgery. Although current methods for leakage prevention have different levels of clinical efficacy, they are until now imperfect solutions. Stem cell therapy using ASC sheets could provide a solution to this problem. ASCs are considered as promising candidates for promoting tissue healing because of their trophic and immunomodulatory properties. Here, we provide methods to produce high-density ASC sheets, that are transplanted onto a colorectal anastomosis in a rat model to reduce the leakage. ASCs formed cell sheets in thermo-responsive culture dishes that could be easily detached. On the day of the transplantation, a partial colectomy with a 5-suture colorectal anastomosis was performed. Animals were immediately transplanted with 1 ASC sheet per rat. ASC sheets adhered spontaneously to the anastomosis without any glue, suture, or any biomaterial. Animal groups were sacrificed 3 and 7 days postoperatively. Compared to transplanted animals, the incidence of anastomotic abscesses and leakage was higher in control animals. In our model, the transplantation of ASC sheets after colorectal anastomosis was successful and associated with a lower leakage rate.

Bioengineered tissue solutions for repair, correction and reconstruction in cardiovascular surgery

The treatment of cardiac alterations is still nowadays a dramatic issue in the cardiosurgical practice. Synthetic materials applied in this surgery have failed in their long-term therapeutic efficacy due to low biocompatibility and compliance, especially when used in contractile sites. In order to overcome these treatment pitfalls, novel solutions have been developed based on biological tissues. Patches in pericardium, small intestinal submucosa, as well as engineered tissues of myocardium, heart valves and blood vessels have undergone a large preclinical investigation in regenerative medicine studies. Clinical translation has been started or reached by several of these new bioengineered treatment alternatives. This review will describe the preclinical and clinical experiences realized so far with the application of biological tissues in cardiovascular surgery. It will depict the progressive steps realized in the evolution of this research, as well as it will point out the challenges yet to face in order to generate the ideal biomaterial for cardiovascular repair, corrective and reconstructive surgery.

Layered smooth muscle cell-endothelial progenitor cell sheets derived from the bone marrow augment postinfarction ventricular function

OBJECTIVE

The angiogenic potential of endothelial progenitor cells (EPCs) may be limited by the absence of their natural biologic foundation, namely smooth muscle pericytes. We hypothesized that joint delivery of EPCs and smooth muscle cells (SMCs) in a novel, totally bone marrow-derived cell sheet will mimic the native architecture of a mature blood vessel and act as an angiogenic construct to limit post infarction ventricular remodeling.

METHODS

Primary EPCs and mesenchymal stem cells were isolated from bone marrow of Wistar rats. Mesenchymal stem cells were transdifferentiated into SMCs by culture on fibronectin-coated culture dishes. Confluent SMCs topped with confluent EPCs were detached from an Upcell dish to create a SMC-EPC bi-level cell sheet. A rodent model of ischemic cardiomyopathy was then created by ligating the left anterior descending artery. Rats were randomized into 3 groups: cell sheet transplantation (n = 9), no treatment (n = 12), or sham surgery control (n = 7).

RESULTS

Four weeks postinfarction, mature vessel density tended to increase in cell sheet-treated animals compared with controls. Cell sheet therapy significantly attenuated the extent of cardiac fibrosis compared with that of the untreated group (untreated vs cell sheet, 198 degrees [interquartile range (IQR), 151-246 degrees] vs 103 degrees [IQR, 92-113 degrees], P = .04). Furthermore, EPC-SMC cell sheet transplantation attenuated myocardial dysfunction, as evidenced by an increase in left ventricular ejection fraction (untreated vs cell sheet vs sham, 33.5% [IQR, 27.8%-35.7%] vs 45.9% [IQR, 43.6%-48.4%] vs 59.3% [IQR, 58.8%-63.5%], P = .001) and decreases in left ventricular dimensions.

CONCLUSIONS

The bone marrow-derived, spatially arranged SMC-EPC bi-level cell sheet is a novel, multilineage cellular therapy obtained from a translationally practical source. Interactions between SMCs and EPCs augment mature neovascularization, limit adverse remodeling, and improve ventricular function after myocardial infarction.

Mesenchymal stem cells and myoblast differentiation under HGF and IGF-1 stimulation for 3D skeletal muscle tissue engineering

Background

Volumetric muscle loss caused by trauma or after tumour surgery exceeds the natural regeneration capacity of skeletal muscle. Hence, the future goal of tissue engineering (TE) is the replacement and repair of lost muscle tissue by newly generating skeletal muscle combining different cell sources, such as myoblasts and mesenchymal stem cells (MSCs), within a three-dimensional matrix. Latest research showed that seeding skeletal muscle cells on aligned constructs enhance the formation of myotubes as well as cell alignment and may provide a further step towards the clinical application of engineered skeletal muscle.

In this study the myogenic differentiation potential of MSCs upon co-cultivation with myoblasts and under stimulation with hepatocyte growth factor (HGF) and insulin-like growth factor-1 (IGF-1) was evaluated. We further analysed the behaviour of MSC-myoblast co-cultures in different 3D matrices.

Results

Primary rat myoblasts and rat MSCs were mono- and co-cultivated for 2, 7 or 14 days. The effect of different concentrations of HGF and IGF-1 alone, as well as in combination, on myogenic differentiation was analysed using microscopy, multicolour flow cytometry and real-time PCR. Furthermore, the influence of different three-dimensional culture models, such as fibrin, fibrin-collagen-I gels and parallel aligned electrospun poly-ε-caprolacton collagen-I nanofibers, on myogenic differentiation was analysed. MSCs could be successfully differentiated into the myogenic lineage both in mono- and in co-cultures independent of HGF and IGF-1 stimulation by expressing desmin, myocyte enhancer factor 2, myosin heavy chain 2 and alpha-sarcomeric actinin. An increased expression of different myogenic key markers could be observed under HGF and IGF-1 stimulation. Even though, stimulation with HGF/IGF-1 does not seem essential for sufficient myogenic differentiation. Three-dimensional cultivation in fibrin-collagen-I gels induced higher levels of myogenic differentiation compared with two-dimensional experiments. Cultivation on poly-ε-caprolacton-collagen-I nanofibers induced parallel alignment of cells and positive expression of desmin.

Conclusions

In this study, we were able to myogenically differentiate MSC upon mono- and co-cultivation with myoblasts. The addition of HGF/IGF-1 might not be essential for achieving successful myogenic differentiation. Furthermore, with the development of a biocompatible nanofiber scaffold we established the basis for further experiments aiming at the generation of functional muscle tissue.

Electronic supplementary material

The online version of this article (doi:10.1186/s12860-017-0131-2) contains supplementary material, which is available to authorized users.

Endothelial differentiation of bone marrow mesenchyme stem cells applicable to hypoxia and increased migration through Akt and NFκB signals

BACKGROUND

Bone marrow mesenchymal stem cells (MSCs) and endothelial progenitor cells (EPCs) are used to repair hypoxic or ischemic tissue. However, the underlining mechanism of resistance in the hypoxic microenvironment and the efficacy of migration to the injured tissue are still unknown. The current study aims to understand the hypoxia resistance and migration ability of MSCs during differentiation toward endothelial lineages by biochemical and mechanical stimuli.

METHOD

MSCs were harvested from the bone marrow of 6-8-week-old Sprague-Dawley rats. The endothelial growth medium (EGM) was added to MSCs for 3 days to initiate endothelial differentiation. Laminar shear stress was used as the fluid mechanical stimulation.

RESULTS

Application of EGM facilitated the early endothelial lineage cells (eELCs) to express EPC markers. When treating the hypoxic mimetic desferrioxamine, both MSCs and eELCs showed resistance to hypoxia as compared with the occurrence of apoptosis in rat fibroblasts. The eELCs under hypoxia increased the wound closure and C-X-C chemokine receptor type 4 (CXCR4) gene expression. Although the shear stress promoted eELC maturation and aligned cells parallel to the flow direction, their migration ability was not superior to that of eELCs either under normoxia or hypoxia. The eELCs showed higher protein expressions of CXCR4, phosphorylated Akt (pAkt), and endogenous NFκB and IκBα than MSCs under both normoxia and hypoxia conditions. The potential migratory signals were discovered by inhibiting either Akt or NFκB using specific inhibitors and revealed decreases of wound closure and transmigration ability in eELCs.

CONCLUSION

The Akt and NFκB pathways are important to regulate the early endothelial differentiation and its migratory ability under a hypoxic microenvironment.

Isolation and trans-differentiation of mesenchymal stromal cells into smooth muscle cells: Utility and applicability for cell-sheet engineering

BACKGROUND

Bone marrow (BM)-derived mesenchymal stromal cells (MSCs) have shown potential to differentiate into various cell types, including smooth muscle cells (SMCs). The extracellular matrix (ECM) represents an appealing and readily available source of SMCs for use in tissue engineering. In this study, we hypothesized that the ECM could be used to induce MSC differentiation to SMCs for engineered cell-sheet construction.

METHODS

Primary MSCs were isolated from the BM of Wistar rats, transferred and cultured on dishes coated with 3 different types of ECM: collagen type IV (Col IV), fibronectin (FN), and laminin (LM). Primary MSCs were also included as a control. The proportions of SMC (a smooth muscle actin [aSMA] and SM22a) and MSC markers were examined with flow cytometry and Western blotting, and cell proliferation rates were also quantified.

RESULTS

Both FN and LM groups were able to induce differentiation of MSCs toward smooth muscle-like cell types, as evidenced by an increase in the proportion of SMC markers (aSMA; Col IV 42.3 ± 6.9%, FN 65.1 ± 6.5%, LM 59.3 ± 7.0%, Control 39.9 ± 3.1%; P = 0.02, SM22; Col IV 56.0 ± 7.7%, FN 74.2 ± 6.7%, LM 60.4 ± 8.7%, Control 44.9 ± 3.6%) and a decrease in that of MSC markers (CD105: Col IV 64.0 ± 5.2%, FN 57.6 ± 4.0%, LM 60.3 ± 7.0%, Control 85.3 ± 4.2%; P = 0.03). The LM group showed a decrease in overall cell proliferation, whereas FN and Col IV groups remained similar to control MSCs (Col IV, 9.0 ± 2.3%; FN, 9.8 ± 2.5%; LM, 4.3 ± 1.3%; Control, 9.8 ± 2.8%).

CONCLUSIONS

Our findings indicate that ECM selection can guide differentiation of MSCs into the SMC lineage. Fibronectin preserved cellular proliferative capacity while yielding the highest proportion of differentiated SMCs, suggesting that FN-coated materials may be facilitate smooth muscle tissue engineering.

Building A New Treatment For Heart Failure-Transplantation of Induced Pluripotent Stem Cell-derived Cells into the Heart

Advanced cardiac failure is a progressive intractable disease and is the main cause of mortality and morbidity worldwide. Since this pathology is represented by a definite decrease in cardiomyocyte number, supplementation of functional cardiomyocytes into the heart would hypothetically be an ideal therapeutic option. Recently, unlimited in vitro production of human functional cardiomyocytes was established by using induced pluripotent stem cell (iPSC) technology, which avoids the use of human embryos. A number of basic studies including ours have shown that transplantation of iPSC-derived cardiomyocytes (iPSC-CMs) into the damaged heart leads to recovery of cardiac function, thereby establishing “proof-of-concept” of this iPSC-transplantation therapy. However, considering clinical application of this therapy, its feasibility, safety, and therapeutic efficacy need to be further investigated in the pre-clinical stage. This review summarizes up-to-date important topics related to safety and efficacy of iPSC-CMs transplantation therapy for cardiac disease and discusses the prospects for this treatment in clinical studies.

The Mutual Interactions between Mesenchymal Stem Cells and Myoblasts in an Autologous Co-Culture Model

Both myoblasts and mesenchymal stem cells (MSC) take part in the muscle tissue regeneration and have been used as experimental cellular therapy in muscular disorders treatment. It is possible that co-transplantation approach could improve the efficacy of this treatment. However, the relations between those two cell types are not clearly defined. The aim of this study was to determine the reciprocal interactions between myoblasts and MSC in vitro in terms of the features important for the muscle regeneration process. Primary caprine muscle-derived cells (MDC) and bone marrow-derived MSC were analysed in autologous settings. We found that MSC contribute to myotubes formation by fusion with MDC when co-cultured directly, but do not acquire myogenic phenotype if exposed to MDC-derived soluble factors only. Experiments with exposure to hydrogen peroxide showed that MSC are significantly more resistant to oxidative stress than MDC, but a direct co-culture with MSC does not diminish the cytotoxic effect of H2O2 on MDC. Cell migration assay demonstrated that MSC possess significantly greater migration ability than MDC which is further enhanced by MDC-derived soluble factors, whereas the opposite effect was not found. MSC-derived soluble factors significantly enhanced the proliferation of MDC, whereas MDC inhibited the division rate of MSC. To conclude, presented results suggest that myogenic precursors and MSC support each other during muscle regeneration and therefore myoblasts-MSC co-transplantation could be an attractive approach in the treatment of muscular disorders.

Adipose stem cell sheets improved cardiac function in the rat myocardial infarction, but did not alter cardiac contractile responses to β-adrenergic stimulation

Adipose stem cells (ASCs) are a source of regenerative cells available for autologous transplantation to hearts. We compared protective actions of ASC sheets on rat myocardial infarction (MI) in comparison with those of skeletal myoblast cell sheets. Their effects on infarcted hearts were evaluated by biological, histochemical as well as physiological analyses. ASC sheets secreted higher concentrations of angiogenic factors (HGF, VEGF, and bFGF; P < 0.05) under normoxic and hypoxic conditions than those of myoblast cell sheets, associated with reduction of cell apoptosis (P < 0.05). Like myoblast cell sheets, ASC sheets improved cardiac function (P < 0.05) and decreased the plasma level of ANP (P < 0.05) in MI hearts. ASC sheets restored cardiac remodeling characterized by fibrosis, cardiac hypertrophy and impaired angiogenesis (P < 0.05), which was associated with increases in angiogenic factors (P < 0.05). In isolated perfused rat hearts, ASC sheets improved both systolic and diastolic functions, which was comparable to cardiac functions of myoblast cell sheets, while both cell sheets failed to restore cardiac contractile response to either isoproterenol, pimobendan or dibutyryl cAMP. These results indicated that ASC sheets improved cardiac function and remodeling of MI hearts mediated by their paracrine action and this improvement was comparable to those by myoblast cell sheets.

A Tissue-Engineered Chondrocyte Cell Sheet Induces Extracellular Matrix Modification to Enhance Ventricular Biomechanics and Attenuate Myocardial Stiffness in Ischemic Cardiomyopathy

There exists a substantial body of work describing cardiac support devices to mechanically support the left ventricle (LV); however, these devices lack biological effects. To remedy this, we implemented a cell sheet engineering approach utilizing chondrocytes, which in their natural environment produce a relatively elastic extracellular matrix (ECM) for a cushioning effect. Therefore, we hypothesized that a chondrocyte cell sheet applied to infarcted and borderzone myocardium will biologically enhance the ventricular ECM and increase elasticity to augment cardiac function in a model of ischemic cardiomyopathy (ICM). Primary articular cartilage chondrocytes of Wistar rats were isolated and cultured on temperature-responsive culture dishes to generate cell sheets. A rodent ICM model was created by ligating the left anterior descending coronary artery. Rats were divided into two groups: cell sheet transplantation (1.0 × 10(7) cells/dish) and no treatment. The cell sheet was placed onto the surface of the heart covering the infarct and borderzone areas. At 4 weeks following treatment, the decreased fibrotic extension and increased elastic microfiber networks in the infarct and borderzone areas correlated with this technology's potential to stimulate ECM formation. The enhanced ventricular elasticity was further confirmed by the axial stretch test, which revealed that the cell sheet tended to attenuate tensile modulus, a parameter of stiffness. This translated to increased wall thickness in the infarct area, decreased LV volume, wall stress, mass, and improvement of LV function. Thus, the chondrocyte cell sheet strengthens the ventricular biomechanical properties by inducing the formation of elastic microfiber networks in ICM, resulting in attenuated myocardial stiffness and improved myocardial function.

A bioengineered hydrogel system enables targeted and sustained intramyocardial delivery of neuregulin, activating the cardiomyocyte cell cycle and enhancing ventricular function in a murine model of ischemic cardiomyopathy

BACKGROUND

Neuregulin-1β (NRG) is a member of the epidermal growth factor family possessing a critical role in cardiomyocyte development and proliferation. Systemic administration of NRG demonstrated efficacy in cardiomyopathy animal models, leading to clinical trials using daily NRG infusions. This approach is hindered by requiring daily infusions and off-target exposure. Therefore, this study aimed to encapsulate NRG in a hydrogel to be directly delivered to the myocardium, accomplishing sustained localized NRG delivery.

METHODS AND RESULTS

NRG was encapsulated in hydrogel, and release over 14 days was confirmed by ELISA in vitro. Sprague-Dawley rats were used for cardiomyocyte isolation. Cells were stimulated by PBS, NRG, hydrogel, or NRG-hydrogel (NRG-HG) and evaluated for proliferation. Cardiomyocytes demonstrated EdU (5-ethynyl-2'-deoxyuridine) and phosphorylated histone H3 positivity in the NRG-HG group only. For in vivo studies, 2-month-old mice (n=60) underwent left anterior descending coronary artery ligation and were randomized to the 4 treatment groups mentioned. Only NRG-HG-treated mice demonstrated phosphorylated histone H3 and Ki67 positivity along with decreased caspase-3 activity compared with all controls. NRG was detected in myocardium 6 days after injection without evidence of off-target exposure in NRG-HG animals. At 2 weeks, the NRG-HG group exhibited enhanced left ventricular ejection fraction, decreased left ventricular area, and augmented borderzone thickness.

CONCLUSIONS

Targeted and sustained delivery of NRG directly to the myocardial borderzone augments cardiomyocyte mitotic activity, decreases apoptosis, and greatly enhances left ventricular function in a model of ischemic cardiomyopathy. This novel approach to NRG administration avoids off-target exposure and represents a clinically translatable strategy in myocardial regenerative therapeutics.

Myocardial transfection of hypoxia-inducible factor-1α and co-transplantation of mesenchymal stem cells enhance cardiac repair in rats with experimental myocardial infarction

Introduction

Mesenchymal stem cells (MSCs) have potential for the treatment of myocardial infarction. However, several meta-analyses revealed that the outcome of stem cell transplantation is dissatisfactory. A series of studies demonstrated that the combination of cell and gene therapy was a promising strategy to enhance therapeutic efficiency. The aim of this research is to investigate whether and how the combination of overexpression of hypoxia-inducible factor-1α (HIF-1α) and co-transplantation of mesenchymal stem cells can enhance cardiac repair in myocardial infarction.

Methods

We investigated the therapeutic effects of myocardial transfection of HIF-1α and co-transplantation of MSCs on cardiac repair in myocardial infarction by using myocardial transfection of HIF-1α via an adenoviral vector. Myocardial infarction was produced by coronary ligation in Sprague-Dawley (SD) rats. Animals were divided randomly into six groups: (1) HIF-1α + MSCs group: Ad-HIF-1α (6 × 10⁹ plate forming unit) and MSCs (1 × 10⁶) were intramyocardially injected into the border zone simultaneously; (2) HIF-1α group: Ad-HIF-1α (6 × 10⁹ plate forming unit) was injected into the border zone; (3) HIF-1α-MSCs group: Ad-HIF-1α transfected MSCs (1 × 10⁶) were injected into the border zone; (4) MSCs group: MSCs (1 × 10⁶) were injected into the border zone; (5) Control group: same volume of DMEM was injected; (6) SHAM group. Cardiac performance was then quantified by echocardiography as well as molecular and pathologic analysis of heart samples in the peri-infarcted region and the infarcted region at serial time points. The survival and engraftment of transplanted MSCs were also assessed.

Results

Myocardial transfection of HIF-1α combined with MSC transplantation in the peri-infarcted region improved cardiac function four weeks after myocardial infarction. Significant increases in vascular endothelial growth factor (VEGF) and stromal cell-derived factor-1α (SDF-1α) expression, angiogenesis and MSC engraftment, as well as decreased cardiomyocyte apoptosis in peri-infarcted regions in the hearts of the HIF-1α + MSCs group were detected compared to the MSCs group and Control group.

Conclusions

These findings suggest that myocardial transfection of HIF-1α and co-transplantation of mesenchymal stem cells enhance cardiac repair in myocardial infarction, indicating the feasibility and preliminary safety of a combination of myocardial transfection of HIF-1α and MSC transplantation to treat myocardial infarction.