Nanomaterials for Cardiac Tissue Engineering Application

In recent years, the emerging cardiac tissue engineering provides a new therapeutic method for heart diseases. And in the tissue engineering, the scaffold material which can mimic the structure of the extracellular matrix properly is a key factor. The rapid expansion of nano-scaffolds during the past ten years has led to new perspectives and advances in biomedical research as well as in clinical practice. Here we search articles published in recent years extensively on cardiac tissue engineering scaffold materials and nanotechnology. And we review the traditional scaffold materials and the advances of the nano-scaffolds in cardiac tissue engineering. A thorough understanding of the nano-scaffolds would enable us to better exploit technologies to research the ideal scaffold material, and promote the cardiac tissue engineering using in the clinical practice as soon as possible.

A multi-axis robot-based bioprinting system supporting natural cell function preservation and cardiac tissue fabrication

Despite the recent advances in artificial tissue and organ engineering,how to generate large size viable and functional complex organs still remains as a grand challenge for regenerative medicine.Three-dimensional bioprinting has demonstrated its advantages as one of the major methods in fabricating simple tissues,yet it still faces difficulties to generate vasculatures and preserve cell functions in complex organ production.Here,we overcome the limitations of conventional bioprinting systems by converting a six degree-of-freedom robotic arm into a bioprinter,therefore enables cell printing on 3D complex-shaped vascular scaffolds from all directions.We also developed an oil bath-based cell printing method to better preserve cell natural functions after printing.Together with a self-designed bioreactor and a repeated print-and-culture strategy,our bioprinting system is capable to generate vascularized,contractible,and long-term survived cardiac tissues.Such bioprinting strategy mimics the in vivo organ development process and presents a promising solution for in vitro fabrication of complex organs.

From waste of marine culture to natural patch in cardiac tissue engineering

Sea squirt,as a highly invasive species and main biofouling source in marine aquaculture,has seriously threatened the biodiversity and aquaculture economy.On the other hand,a conductive biomaterial with excellent biocompatibility,and appropriate mechanical property from renewable resources is urgently required for tissue engineering patches.To meet these targets,we presented a novel and robust strategy for sustainable development aiming at the marine pollution via recycling and upgrading the waste biomass-sea squirts and serving as a renewable resource for functional bio-scaffold patch in tissue engineering.We firstly demonstrated that the tunic cellulose derived natural self-conductive scaffolds successfully served as functional cardiac patches,which significantly promote the maturation and spontaneous contraction of cardiomyocytes both in vitro and enhance cardiac function of MI rats in vivo.We believe this novel,feasible and“Trash to Treasure”strategy to gain cardiac patches via recycling the waste biomass must be promising and beneficial for marine environmental bio-pollution issue and sustainable development considering the large-scale consumption potential for tissue engineering and other applications.

Cardiac tissue-derived extracellular matrix scaffolds for myocardial repair:advantages and challenges

Decellularized extracellular matrix(dECM)derived from myocardium has been widely explored as a nature scaffold for cardiac tissue engineering applications.Cardiac dECM offers many unique advantages such as preservation of organ-specific ECM microstructure and composition,demonstration of tissue-mimetic mechanical properties and retention of biochemical cues in favor of subsequent recellularization.However,current processes of dECM decellularization and recellularization still face many challenges including the need for balance between cell removal and extracellular matrix preservation,efficient recellularization of dECM for obtaining homogenous cell distribution,tailoring material properties of dECM for enhancing bioactivity and prevascularization of thick dECM.This review summarizes the recent progresses of using dECM scaffold for cardiac repair and discusses its major advantages and challenges for producing biomimetic cardiac patch.

Conductive nanomaterials for cardiac tissues engineering

Myocardial infarction(MI)is a worldwide disease with high incidence and high fatality rate.In the past decade,a lot of research work based on the method of cardiac tissues engineering has received wide attention from re-searchers and has been demonstrated to have important application prospects in the treatment of MI.To make engineered cardiac tissue(ECTs)simulate the characteristics of the natural myocardial microenvironment better,the unique electrophysiological characteristics of myocardial tissue should be considered.Therefore,conductive nanomaterials are adopted to construct ECTs to make up for the lack of traditional scaffold materials.In this arti-cle,the research progresses of conductive nanomaterials application in the field of cardiac tissue engineering are summarized,and two treatment strategies of cardiac patch construction and injectable materials for MI treatment are discussed respectively.Related research work provided reference for the study of cardiac tissue engineering based conductive nanomaterials.

Superaligned carbon nanotubes guide oriented cell growth and promote electrophysiological homogeneity for synthetic cardiac tissues

With the support by the National Natural Science Foundation of China,the research team led by Professor Li Yigang(李毅刚)at Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine and Professor Peng Huisheng(彭慧胜)at Fudan University presented a new type of

Tissue Extracts From Infarcted Myocardium of Rats in Promoting the Differentiation of Bone Marrow Stromal Cells Into Cardiomyocyte-like Cells

Objective To investigate whether cardiac tissue extracts from rats could mimic the cardiac microenvironment and act as a natural inducer in promoting the differentiation of bone marrow stromal cells （BMSCs） into cardiomyocytes. Methods Three kinds of tissue extract or cell lysate [infarcted myocardial tissue extract （IMTE）, normal myocardial tissue extract （NMTE） and cultured neonatal myocardial lysate （NML）] were employed to induce BMSCs into cardiomyocyte-like cells. The cells were harvested at each time point for reverse transcription-polymerase chain reaction （RT-PCR） detection, immunocytochemical analysis, and transmission electron microscopy. Results After a 7-day induction, BMSCs were enlarged and polygonal in morphology. Myofilaments, striated sarcomeres, Z-lines, and more mitochondia were observed under transmission electron microscope. Elevated expression levels of cardiac-specific genes and proteins were also confirmed by RT-PCR and immunocytochemistry. Moreover, IMTE showed a greater capacity of differentiating BMSCs into cardiomyocyte-like cells. Conclusions Cardiac tissue extracts, especially IMTE, can effectively differentiate BMSCs into cardiomyocyte-like cells.

Generation of ring-shaped human iPSC-derived functional heart microtissues in a M?bius strip configuration

Although human-induced pluripotent stem cell-derived cardiomyocytes(hi PSC-CMs) have been used for disease modeling and drug discovery, clinically relevant three-dimensional(3D) functional myocardial microtissues are lacking. Here, we developed a novel ring-shaped cardiac microtissue comprised of chamber-specific tissues to achieve a geometrically non-orientable ventricular myocardial band, similar to a M?bius loop. The ring-shaped cardiac tissue was constructed of hi PSC-CMs and human cardiac fibroblasts(h CFs) through a facile cellular self-assembly approach. It exhibited basic anatomical structure,positive cardiac troponin T(c Tn T) immunostaining, regular calcium transients, and cardiac-like mechanical strength. The cardiac rings can be self-assembled and scaled up into various sizes with outstanding stability, suggesting their potential for precise therapy, pathophysiological investigation, and large-scale drug screening.

Alterations in Low-Z Elements Distribution in Heart Tissue after Treatments to Breast Cancer Using LEXRF Technique

Data from Global Cancer Statistics show that breast cancer (BC) is the most common type of cancer among women, leading the number of deaths caused by cancer. The developments in diagnosis and treatment techniques for the BC, including chemotherapy and/or radiotherapy, increased the survival rates for this type of cancer. One late complication induced by BC treatment is the cardiotoxicity. This term comprises different cardiotoxic side effects, which include blood pressure alterations, myocardial ischemia, congestive heart failure and other damages. This study aimed to evaluate the cardiac alterations induced by radiotherapy and chemotherapy, simulating a treatment for BC in Wistar rats. It is, therefore, important to understand the mechanisms involved in the cardiotoxicity, in order to prevent women from this late effect, when they undergo BC treatments. The major interests in this work are in Low atomic weight elements as Sodium, because it is strongly related to cardiomyocyte contraction;Magnesium, because it is important in the cardiac metabolism;and Iron, because BC treatment induced cardiotoxicity can be associated to the oxidative stress. Changes that occur in unhealthy tissues in case to cardiovascular damages can be better understood when elemental compounds and structures of healthy tissues are known. Low Energy X-ray Fluorescence (LEXRF) technique was used to obtain elemental maps of low Z-elements providing a semi-quantitative analysis of the tissues evaluated under different conditions. Through the technique LEXRF we obtained elemental and absorption maps. The results showed more damages when associating chemotherapy and radiotherapy in comparison to myocardium healthy. Those images taken together with light microscopy, X-ray absorption and phase contrast images, satisfactorily characterize the cardiac tissue for the first time in the literature, from the structural and morphological points of view. LEXRF was carried out at TwinMic beamline in the ELETTRA Synchrotron Fa-cility, at the beamline TwinMic, in Trieste, Italy.

Total soy saponins improve the antioxidant capacity of the myocardium and exercise ability in exhausted rats

Purpose：The aim of the present study was to investigate the impact of total soy saponins（TS） on the myocardial antioxidant capacity in rats exercised to exhaustion.Methods：The one-time exhausted treadmill model was used.All rats were divided into 4 groups：the control group,the TS group,the exhausted group,and the TS exhausted group.The TS and TS exhausted groups were fed TS at a dosage of 20 mg/kg body weight,once a day,for 2 weeks.The exhausted group was given a placebo,and the control group was not given any treatment.The treadmill speed was set at 30 m/min,and the rats（exhausted and TS exhausted groups） were trained at this speed until exhausted.The rats were decapitated and anatomized immediately after exhausted.A 10% homogenate of the myocardial tissue was prepared.Results：TS significant y increased the exercise time by 20.62%（p〈0.05）.As compared with the control group,the enzyme activities for catalase（CAT）,glutathione peroxidase（GSH-Px）,and glutathione reductase（GR） were significant y enhanced in the TS group（p〈0.01）;GR and GSH-Px activity was significant y enhanced in the TS exhausted group（p〈0.01）;malondialdehyde（MDA） levels were significant y decreased in the TS exhausted group（p〈0.05）.As compared with the exhausted group,the GSH-Px activity was significant y enhanced in the TS exhausted group（p〈0.01）;CAT,GSH-Px,and GR activities were significant y enhanced in the TS group（p〈0.01）.As compared with the TS group,the CAT and GR activity in the TS exhausted group was significant y decreased（p〈0.01）.Conclusion：TS can improve the exercised rats＇ antioxidant activity in their cardiac muscle to varying degrees,decrease MDA and serum AST and LDH levels,increase the exercise time,and delay the occurrence of sports fatigue.

Combination of mesenchymal stem cells and three-dimensional collagen scaffold preserves ventricular remodeling in rat myocardial infarction model

BACKGROUND Cardiovascular diseases are the major cause of mortality worldwide.Regeneration of the damaged myocardium remains a challenge due to mechanical constraints and limited healing ability of the adult heart tissue.Cardiac tissue engineering using biomaterial scaffolds combined with stem cells and bioactive molecules could be a highly promising approach for cardiac repair.Use of biomaterials can provide suitable microenvironment to the cells and can solve cell engraftment problems associated with cell transplantation alone.Mesenchymal stem cells(MSCs)are potential candidates in cardiac tissue engineering because of their multilineage differentiation potential and ease of isolation.Use of DNA methyl transferase inhibitor,such as zebularine,in combination with three-dimensional(3D)scaffold can promote efficient MSC differentiation into cardiac lineage,as epigenetic modifications play a fundamental role in determining cell fate and lineage specific gene expression.AIM To investigate the role of collagen scaffold and zebularine in the differentiation of rat bone marrow(BM)-MSCs and their subsequent in vivo effects.METHODS MSCs were isolated from rat BM and characterized morphologically,immunophenotypically and by multilineage differentiation potential.MSCs were seeded in collagen scaffold and treated with 3μmol/L zebularine in three different ways.Cytotoxicity analysis was done and cardiac differentiation was analyzed at the gene and protein levels.Treated and untreated MSC-seeded scaffolds were transplanted in the rat myocardial infarction(MI)model and cardiac function was assessed by echocardiography.Cell tracking was performed by DiI dye labeling,while regeneration and neovascularization were evaluated by histological and immunohistochemical analysis,respectively.RESULTS MSCs were successfully isolated and seeded in collagen scaffold.Cytotoxicity analysis revealed that zebularine was not cytotoxic in any of the treatment groups.Cardiac differentiation analysis showed more pronounced results in the type 3 treatment group which was subsequently chosen for the transplantation in the in vivo MI model.Significant improvement in cardiac function was observed in the zebularine treated MSC-seeded scaffold group as compared to the MI control.Histological analysis also showed reduction in fibrotic scar,improvement in left ventricular wall thickness and preservation of ventricular remodeling in the zebularine treated MSC-seeded scaffold group.Immunohistochemical analysis revealed significant expression of cardiac proteins in DiI labeled transplanted cells and a significant increase in the number of blood vessels in the zebularine treated MSC-seeded collagen scaffold transplanted group.CONCLUSION Combination of 3D collagen scaffold and zebularine treatment enhances cardiac differentiation potential of MSCs,improves cell engraftment at the infarcted region,reduces infarct size and improves cardiac function.

Gelatin-based hydrogels combined with electrical stimulation to modulate neonatal rat cardiomyocyte beating and promote maturation

Cardiovascular diseases are the leading cause of morbidity and mortality throughout the world underlining the importance of efficient treatments including disease modeling and drug discovery by cardiac tissue engineering.However,the predictive power of these applications is currently limited by the immature state of the cardiomyocytes.Here,we developed gelatin hydrogels chemically crosslinked by genipin,a biocompatible crosslinker,as cell culture scaffolds.Neonatal rat cardiomyocytes appear synchronous beatingwithin 2 days after seeding on hydrogels.Furthermore,we applied the electrical stimulation as a conditioning treatment to promote the maturation of cardiomyocytes cultured on the hydrogels.Our results show that electrical stimulation improves the organization of sarcomeres,establishment of gap junctions,calcium-handling capacity and propagation of pacing signals,thereby,increase the beating velocity of cardiomyocytes and responsiveness to external pacing.The above system can be applied in promoting physiological function maturation of engineered cardiac tissues,exhibiting promising applications in cardiac tissue engineering and drug screening.

Cardiac mechanostructure: Using mechanics and anisotropy as inspiration for developing epicardial therapies in treating myocardial infarction

The mechanical environment and anisotropic structure of the heart modulate cardiac function at the cellular,tissue and organ levels.During myocardial infarction(MI)and subsequent healing,however,this landscape changes significantly.In order to engineer cardiac biomaterials with the appropriate properties to enhance function after MI,the changes in the myocardium induced by MI must be clearly identified.In this review,we focus on the mechanical and structural properties of the healthy and infarcted myocardium in order to gain insight about the environment in which biomaterial-based cardiac therapies are expected to perform and the functional deficiencies caused by MI that the therapy must address.From this understanding,we discuss epicardial therapies for MI inspired by the mechanics and anisotropy of the heart focusing on passive devices,which feature a biomaterials approach,and active devices,which feature robotic and cellular components.Through this review,a detailed analysis is provided in order to inspire further development and translation of epicardial therapies for MI.

Local administration of porcine immunomodulatory,chemotactic and angiogenic extracellular vesicles using engineered cardiac scaffolds for myocardial infarction

The administration of extracellular vesicles(EV)from mesenchymal stromal cells(MSC)is a promising cell-free nanotherapy for tissue repair after myocardial infarction(MI).However,the optimal EV delivery strategy remains undetermined.Here,we designed a novel MSC-EV delivery,using 3D scaffolds engineered from decellularised cardiac tissue as a cell-free product for cardiac repair.EV from porcine cardiac adipose tissue-derived MSC(cATMSC)were purified by size exclusion chromatography(SEC),functionally analysed and loaded to scaffolds.cATMSC-EV markedly reduced polyclonal proliferation and pro-inflammatory cytokines production(IFNγ,TNFα,IL12p40)of allogeneic PBMC.Moreover,cATMSC-EV recruited outgrowth endothelial cells(OEC)and allogeneic MSC,and promoted angiogenesis.Fluorescently labelled cATMSC-EV were mixed with peptide hydrogel,and were successfully retained in decellularised scaffolds.Then,cATMSC-EV-embedded pericardial scaffolds were administered in vivo over the ischemic myocardium in a pig model of MI.Six days from implantation,the engineered scaffold efficiently integrated into the post-infarcted myocardium.cATMSC-EV were detected within the construct and MI core,and promoted an increase in vascular density and reduction in macrophage and T cell infiltration within the damaged myocardium.The confined administration of multifunctional MSC-EV within an engineered pericardial scaffold ensures local EV dosage and release,and generates a vascularised bioactive niche for cell recruitment,engraftment and modulation of short-term post-ischemic inflammation.

Biomaterial property-controlled stem cell fates for cardiac regeneration

Myocardial infarction(MI)affects more than 8 million people in the United States alone.Due to the insufficient regeneration capacity of the native myocardium,one widely studied approach is cardiac tissue engineering,in which cells are delivered with or without biomaterials and/or regulatory factors to fully regenerate the cardiac functions.Specifically,in vitro cardiac tissue engineering focuses on using biomaterials as a reservoir for cells to attach,as well as a carrier of various regulatory factors such as growth factors and peptides,providing high cell retention and a proper microenvironment for cells to migrate,grow and differentiate within the scaffolds before implantation.Many studies have shown that the full establishment of a functional cardiac tissue in vitro requires synergistic actions between the seeded cells,the tissue culture condition,and the biochemical and biophysical environment provided by the biomaterials-based scaffolds.Proper electrical stimulation and mechanical stretch during the in vitro culture can induce the ordered orientation and differentiation of the seeded cells.On the other hand,the various scaffolds biochemical and biophysical properties such as polymer composition,ligand concentration,biodegradability,scaffold topography and mechanical properties can also have a significant effect on the cellular processes.

Ferroptosis is essential for diabetic cardiomyopathy and is prevented by sulforaphane via AMPK/NRF2 pathways

Herein,we define the role of ferroptosis in the pathogenesis of diabetic cardiomyopathy(DCM)by examining the expression of key regulators of ferroptosis in mice with DCM and a new ex vivo DCM model.Advanced glycation end-products(AGEs),an important pathogenic factor of DCM,were found to induce ferroptosis in engineered cardiac tissues(ECTs),as reflected through increased levels of Ptgs2 and lipid peroxides and decreased ferritin and SLC7 A11 levels.Typical morphological changes of ferroptosis in cardiomyocytes were observed using transmission electron microscopy.Inhibition of ferroptosis with ferrostatin-1 and deferoxamine prevented AGE-induced ECT remodeling and dysfunction.Ferroptosis was also evidenced in the heart of type 2 diabetic mice with DCM.Inhibition of ferroptosis by liproxstatin-1 prevented the development of diastolic dysfunction at 3 months after the onset of diabetes.Nuclear factor erythroid 2-related factor 2(NRF2)activated by sulforaphane inhibited cardiac cell ferroptosis in both AGE-treated ECTs and hearts of DCM mice by upregulating ferritin and SLC7 A11 levels.The protective effect of sulforaphane on ferroptosis was AMP-activated protein kinase(AMPK)-dependent.These findings suggest that ferroptosis plays an essential role in the pathogenesis of DCM;sulforaphane prevents ferroptosis and associated pathogenesis via AMPK-mediated NRF2 activation.This suggests a feasible therapeutic approach with sulforaphane to clinically prevent ferroptosis and DCM.

Carbon nanomaterials for cardiovascular theranostics:Promises and challenges

Cardiovascular diseases(CVDs)are the leading cause of death worldwide.Heart attack and stroke cause irreversible tissue damage.The currently available treatment options are limited to“damage-control”rather than tissue repair.The recent advances in nanomaterials have offered novel approaches to restore tissue function after injury.In particular,carbon nanomaterials(CNMs)have shown significant promise to bridge the gap in clinical translation of biomaterial based therapies.This family of carbon allotropes(including graphenes,carbon nanotubes and fullerenes)have unique physiochemical properties,including exceptional mechanical strength,electrical conductivity,chemical behaviour,thermal stability and optical properties.These intrinsic properties make CNMs ideal materials for use in cardiovascular theranostics.This review is focused on recent efforts in the diagnosis and treatment of heart diseases using graphenes and carbon nanotubes.The first section introduces currently available derivatives of graphenes and carbon nanotubes and discusses some of the key characteristics of these materials.The second section covers their application in drug delivery,biosensors,tissue engineering and immunomodulation with a focus on cardiovascular applications.The final section discusses current shortcomings and limitations of CNMs in cardiovascular applications and reviews ongoing efforts to address these concerns and to bring CNMs from bench to bedside.