Differentiation of human adipose-derived stem cells into cardiomyocyte-like cells in fibrin scaffold by a histone deacetylase inhibitor

Contractile and Genetic Characterization of Cardiac Constructs Engineered from Human Induced Pluripotent Stem Cells: Modeling of Tuberous Sclerosis Complex and the Effects of Rapamycin

The implementation of three-dimensional tissue engineering concurrently with stem cell technology holds great promise for in vitro research in pharmacology and toxicology and modeling cardiac diseases, particularly for rare genetic and pediatric diseases for which animal models, immortal cell lines, and biopsy samples are unavailable. It also allows for a rapid assessment of phenotype-genotype relationships and tissue response to pharmacological manipulation. Mutations in the TSC1 and TSC2 genes lead to dysfunctional mTOR signaling and cause tuberous sclerosis complex (TSC), a genetic disorder that affects multiple organ systems, principally the brain, heart, skin, and kidneys. Here we differentiated healthy (CC3) and tuberous sclerosis (TSP8-15) human induced pluripotent stem cells (hiPSCs) into cardiomyocytes to create engineered cardiac tissue constructs (ECTCs). We investigated and compared their mechano-elastic properties and gene expression and assessed the effects of rapamycin, a potent inhibitor of the mechanistic target of rapamycin (mTOR). The TSP8-15 ECTCs had increased chronotropy compared to healthy ECTCs. Rapamycin induced positive inotropic and chronotropic effects (i.e., increased contractility and beating frequency, respectively) in the CC3 ECTCs but did not cause significant changes in the TSP8-15 ECTCs. A differential gene expression analysis revealed 926 up- and 439 down-regulated genes in the TSP8-15 ECTCs compared to their healthy counterparts. The application of rapamycin initiated the differential expression of 101 and 31 genes in the CC3 and TSP8-15 ECTCs, respectively. A gene ontology analysis showed that in the CC3 ECTCs, the positive inotropic and chronotropic effects of rapamycin correlated with positively regulated biological processes, which were primarily related to the metabolism of lipids and fatty and amino acids, and with negatively regulated processes, which were predominantly associated with cell proliferation and muscle and tissue development. In conclusion, this study describes for the first time an in vitro TSC cardiac tissue model, illustrates the response of normal and TSC ECTCs to rapamycin, and provides new insights into the mechanisms of TSC.

Cardiac patches made of brown adipose-derived stem cell sheets and conductive electrospun nanofibers restore infarcted heart for ischemic myocardial infarction

Cell sheet engineering has been proven to be a promising strategy for cardiac remodeling post-myocardial infarction. However, insufficient mechanical strength and low cell retention lead to limited therapeutic efficiency. The thickness and area of artificial cardiac patches also affect their therapeutic efficiency. Cardiac patches prepared by combining cell sheets with electrospun nanofibers, which can be transplanted and sutured to the surface of the infarcted heart, promise to solve this problem. Here, we fabricated a novel cardiac patch by stacking brown adipose-derived stem cells (BADSCs) sheet layer by layer, and then they were combined with multi-walled carbon nanotubes (CNTs)-containing electrospun polycaprolactone/silk fibroin nanofibers (CPSN). The results demonstrated that BADSCs tended to generate myocardium-like structures seeded on CPSN. Compared with BADSCs suspension-containing electrospun nanofibers, the transplantation of the CPSN-BADSCs sheets (CNBS) cardiac patches exhibited accelerated angiogenesis and decreased inflammation in a rat myocardial infarction model. In addition, the CNBS cardiac patches could regulate macrophage polarization and promote gap junction remodeling, thus restoring cardiac functions. Overall, the hybrid cardiac patches made of electrospun nanofibers and cell sheets provide a novel solution to cardiac remodeling after ischemic myocardial infarction.

Mesenchymal stem cells in ischemic tissue regeneration

Diseases caused by ischemia are one of the leading causes of death in the world. Current therapies for treating acute myocardial infarction, ischemic stroke, and critical limb ischemia do not complete recovery. Regenerative therapies opens new therapeutic strategy in the treatment of ischemic disorders. Mesenchymal stem cells (MSCs) are the most promising option in the field of cell-based therapies, due to their secretory and immunomodulatory abilities, that contribute to ease inflammation and promote the regeneration of damaged tissues. This review presents the current knowledge of the mechanisms of action of MSCs and their therapeutic effects in the treatment of ischemic diseases, described on the basis of data from in vitro experiments and preclinical animal studies, and also summarize the effects of using these cells in clinical trial settings. Since the obtained therapeutic benefits are not always satisfactory, approaches aimed at enhancing the effect of MSCs in regenerative therapies are presented at the end.

Comparative culture of human corneal endothelial cells following treatment with human platelet lysate/fibrin hydrogel versus Y-27632 ROCK inhibitor: in vitro and ex vivo study

PURPOSE

The advancement of tissue engineering and cell therapy research has resulted in innovative therapeutic options for patients with corneal endothelial diseases. The aim of this study was to compare the potential effect of using human platelet lysate (HPL)/Fibrin hydrogel versus using a Y-27632 ROCK inhibitor, on the culture of human corneal endothelial cells (HCECs) under in vitro and ex vivo conditions.

METHODS

HCECs were isolated from human donors and treated separately with HPL/Fibrin hydrogel, a Y-27632 ROCK inhibitor, and fetal bovine serum (FBS). MTT viability assay and cell counting were performed on the treated cells. Subsequently, we prepared ex vivo models of human corneal endothelial dysfunction and incubated them with DiI-labeled-HCECs. Specular and fluorescence microscopy were then performed on each of the ex vivo models.

RESULTS

In comparison, similar viability results were achieved in the cells treated with HPL/Fibrin hydrogel versus those treated with the Y-27632 ROCK inhibitor, but both treatments showed higher viability than the control group (FBS). More importantly, based on the specular and fluorescence microscopic results, the HPL/Fibrin hydrogel and the Y-27632 ROCK inhibitor treatments showed similar inducible effects on the attachment of the cells to the Descemet membranes of the ex vivo models.

CONCLUSION

HPL/Fibrin hydrogel and Y-27632 ROCK inhibitor have similar inducible effects on the viability and attachment of the HCECs. A definite advantage of treating cells with HPL/Fibrin hydrogel is that it serves as a xeno-free and biocompatible material which can have autologous applications in future usage by clinics.

Potential of a novel scaffold composed of human platelet lysate and fibrin for human corneal endothelial cells

Cell-based therapies have been emerged to find innovative solutions for corneal endothelial dysfunction. The aim of this study is to investigate the suitability of a blended scaffold containing human platelet lysate (HPL) and fibrin not only for cultivating human corneal endothelial cells (HCECs) but also for serving as a scaffold for the respected cells. We isolated HCECs from human donors and encapsulated the cells with three concentrations of HPL/Fibrin scaffold, namely HPL/Fibrin 1, HPL/Fibrin 2 and HPL/Fibrin 3, by adding 28.9, 57.8 and 86.7 mg/dl of fibrinogen to HPL to obtain a final percentage of 10, 20 and 30 % of fibrinogen, respectively. SEM imaging and swelling test were done to characterize the scaffolds. Cell viability assay and cell counting were performed on the cells. HCECs were characterized by morphology and immunocytochemistry. SEM imaging on freeze-dried scaffolds showed higher porosity of HPL/Fibrin 1 and HPL/Fibrin 2 than HPL/Fibrin 3, but larger pores were observed only in HPL/Fibrin 1. Cellular attachment and morphology on HPL/Fibrin 1 were appropriate by SEM imaging. A higher swelling rate was observed in HPL/Fibrin 1. After 3 and 5 days, higher numbers of cells were observed specifically in HPL/Fibrin 1. A higher expression of Na+/K+-ATPase, ZO-1 and vimentin proteins was detected in the HPL/Fibrin 1-cultured HCECs as compared with control (no scaffold). HPL/Fibrin can be used as a suitable scaffold for HCECs while preserving the cells viability. Further investigations are necessitated to approve the beneficial effects of the suggested scaffold for delivering and transplantation of cultivated HCECs into the anterior chamber of the eye.

Cardiac Differentiation of Mesenchymal Stem Cells: Impact of Biological and Chemical Inducers

Cardiovascular disorders (CVDs) are the leading cause of global death, widely occurs due to irreparable loss of the functional cardiomyocytes. Stem cell-based therapeutic approaches, particularly the use of Mesenchymal Stem Cells (MSCs) is an emerging strategy to regenerate myocardium and thereby improving the cardiac function after myocardial infarction (MI). Most of the current approaches often employ the use of various biological and chemical factors as cues to trigger and modulate the differentiation of MSCs into the cardiac lineage. However, the recent advanced methods of using specific epigenetic modifiers and exosomes to manipulate the epigenome and molecular pathways of MSCs to modify the cardiac gene expression yield better profiled cardiomyocyte like cells in vitro. Hitherto, the role of cardiac specific inducers triggering cardiac differentiation at the cellular and molecular level is not well understood. Therefore, the current review highlights the impact and recent trends in employing biological and chemical inducers on cardiac differentiation of MSCs. Thereby, deciphering the interactions between the cellular microenvironment and the cardiac inducers will help us to understand cardiomyogenesis of MSCs. Additionally, the review also provides an insight on skeptical roles of the cell free biological factors and extracellular scaffold assisted mode for manipulation of native and transplanted stem cells towards translational cardiac research.

Effects of hydroxyapatite-coated nonwoven polyethylene/polypropylene fabric on non-mesodermal lineage-specific differentiation of human adipose-derived stem cells

Objective

Compared to other stem cells, the multipotency of human adipose-derived mesenchymal stem cells (ASCs) is limited. Effective approaches that trigger or enhance lineage-specific transdifferentiation are highly envisaged in the improvement of ASCs-based cell therapies. Using Immunofluorescence assays and the secretion of cardiac troponin T (cTnT) protein, we studied the impact of two substrates: Hydroxyapatite (HAp)-coated nonwoven polyethylene (PET)/polypropylene (PP) fabric and glass surfaces, representing 3 dimensional (D) and 2 D environments respectively, on the induction of cardiomyocytes – a non-mesodermal cell type from ASCs for 1–5 weeks.

Results

ASCs were successfully isolated from human adipose tissue under cGMP conditions. Within 1–3 weeks, expression of cTnT in the induced 3D cultures was overall significantly higher (P < 0.021) than that in the induced 2D cultures or controls (P < 0.0009). Remarkably, after 3 weeks of culture, cTnT secretion in the induced 3D cultures gradually declined, nearly reaching levels observed in the 2D cultures. The results show that HAp-coated nonwoven PE/PP fabric could enhance lineage-specific differentiation of ASCs toward cardiac-like cells. However, the fabric might suppress growth of the transformed cells. These preliminary findings encourage further interest in validating the fabric’s potential in improving ASCs transdifferentiation.

Construction of vascularized tissue-engineered bone with polylysine-modified coral hydroxyapatite and a double cell-sheet complex to repair a large radius bone defect in rabbits

In this study, the potential of vascularized tissue-engineered bone constructed by a double cell-sheet (DCS) complex and polylysine (PLL)-modified coralline hydroxyapatite (CHA) to repair large radius bone defects was investigated in rabbits. Firstly, the DCS complex was obtained after rabbit adipose-derived mesenchymal stem cell (ADSC) culture was induced. Secondly, PLL-CHA composite scaffolds with different concentrations of PLL were prepared by the soaking and vacuum freeze-drying methods, and then the scaffolds were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, compression performance testing and cytocompatibility evaluation. Thirdly, DCS-PLL-CHA vascularized tissue-engineered bone was constructed in vitro and transplanted into a large radius bone defect model in rabbits. Finally, the potential of the DCS-PLL-CHA vascularized tissue-engineered bone to repair the large bone defect was evaluated through general observations, laser speckle imaging, scanning electron microscopy (SEM), histological staining, radiography observations and RT-PCR. The in vitro experimental results showed that the DCS complex provided a very large cell reserve, which carried a large number of osteoblasts and vascular endothelial cells that were induced in vitro. When the DCS complex was combined with the PLL-CHA scaffold in vitro, the effects of PLL on cell adhesion, proliferation and differentiation led to a situation similar to the chemotaxis of the body, making the combined complex more conducive to graft cellularization than the DCS complex alone. The in vivo experiments showed blood supply on the surface of the callus in each group, and the amount of blood perfusion on the surface of the defect area was almost equal among the groups. At 12 weeks, the surface of the DCS-PLL-CHA group was completely wrapped by bone tissue and osteoids, the cortical bone image was basically continuous, and the medullary cavity was mainly perforated. A large amount of well-arranged lamellar bone was formed, a small amount of undegraded CHA exhibited a linear pattern, and a large amount of bone filling could be seen in the pores. At 12 weeks, the expression levels of BGLAP, SPP1 and VEGF were similar in each group, but PECAM1 expression was higher in the DCS-PLL-CHA group than in the autogenous bone group and CHA group. The results showed that PLL could effectively promote the adhesion, proliferation and differentiation of ADSCs and that DCS-PLL-CHA vascularized tissue-engineered bone has potential for bone regeneration and bone reconstruction and can be used to repair large bone defects. STATEMENT OF SIGNIFICANCE: 1. PLL-CHA composite scaffolds with different concentrations of PLL were prepared by the soaking and vacuum freeze-drying methods. 2. The vascularized tissue-engineered bone was constructed by the double cell sheet (DCS) complex combined with PLL-CHA scaffolds. 3. The DCS-PLL-CHA vascularized tissue-engineered bone has potential for bone regeneration and bone reconstruction and can be used to repair large bone defects.

The effect of sodium valproate on differentiation of human adipose-derived stem cells into cardiomyocyte-like cells in two-dimensional culture and fibrin scaffold conditions

Differentiation of mesenchymal stem cells (MSCs) into cardiomyocytes is a complex phenomenon, and attempts to find an effective inducing agent are still ongoing. We studied the effect of fibrin scaffold and sodium valproate (VPA, as a histone deacetylase inhibitor) on the differentiation of human adipose-derived stem cells (hADSCs) into cardiomyocyte-like cells. The cells were cultured in culture flask (2D) and in fibrin scaffold (3D), fabricated of human plasma fibrinogen, with and without VPA (1 mM). QRT-PCR, Western blot, and immunochemistry assays were used to evaluate the expression of cardiac markers at gene and protein levels. High levels of CD44, CD90, CD73, and CD105 were expressed on the surface of hADSCs. Treated encapsulated hADSCs (3D) presented significantly higher mRNA expression of HAND1 (1.54-fold), HAND2 (1.59-fold), cTnI (1.76-fold), MLC2v (1.4-fold), Cx43 (1.38-fold), βMHC (1.34-fold), GATA4 (1.48-fold), and NKX2.5 (1.66-fold) in comparison to 2D conditions at four weeks after induction. The protein expressions of NKX2.5 (0.78 vs 0.65), cTnI (1.04 vs 0.81), and Cx43 (1.11 vs 1.08) were observed in the differentiated cells both in 3D and 2D groups, while control cells were absolutely negative for these proteins. The frequency of cTnI and Cx43-positive cells was significantly higher in 3D (24.2 ± 15 and 12 ± 3%) than 2D conditions (19.8 ± 3 and 10 ± 2%). Overall, the results showed that VPA can increase cardiomyogenesis in hADSCs and that fibrin scaffold enhances the inductive effect of VPA. Results of this study may improve cell-based protocols for implementation of more successful cardiac repair strategies.

Improved Efficiency of Cardiomyocyte-Like Cell Differentiation from Rat Adipose Tissue-Derived Mesenchymal Stem Cells with a Directed Differentiation Protocol

Cell-based therapy has become a resource for the treatment of cardiovascular diseases; however, there are some conundrums to achieve. In vitro cardiomyocyte generation could be a solution for scaling options in clinical applications. Variability on cardiac differentiation in previously reported studies from adipose tissue-derived mesenchymal stem cells (ASCs) and the lack of measuring of the cardiomyocyte differentiation efficiency motivate the present study. Here, we improved the ASC-derived cardiomyocyte-like cell differentiation efficiency with a directed cardiomyocyte differentiation protocol: BMP-4 + VEGF (days 0-4) followed by a methylcellulose-based medium with cytokines (IL-6 and IL-3) (days 5-21). Cultures treated with the directed cardiomyocyte differentiation protocol showed cardiac-like cells and “rosette-like structures” from day 7. The percentage of cardiac troponin T- (cTnT-) positive cells was evaluated by flow cytometry to assess the cardiomyocyte differentiation efficiency in a quantitative manner. ASCs treated with the directed cardiomyocyte differentiation protocol obtained a differentiation efficiency of up to 44.03% (39.96%±3.78) at day 15 without any enrichment step. Also, at day 21 we observed by immunofluorescence the positive expression of early, late, and cardiac maturation differentiation markers (Gata-4, cTnT, cardiac myosin heavy chain (MyH), and the sarcoplasmic/endoplasmic reticulum Ca²⁺ ATPase (SERCa2)) in cultures treated with the directed cardiomyocyte differentiation protocol. Unlike other protocols, the use of critical factors of embryonic cardiomyogenesis coupled with a methylcellulose-based medium containing previously reported cardiogenic cytokines (IL-6 and IL-3) seems to be favorable for in vitro cardiomyocyte generation. This novel efficient culture protocol makes ASC-derived cardiac differentiation more efficient. Further investigation is needed to identify an ASC-derived cardiomyocyte surface marker for cardiac enrichment.