scholarly journals Monitoring contractility in single cardiomyocytes and whole hearts with bio-integrated microlasers

2019 ◽  
Author(s):  
Marcel Schubert ◽  
Lewis Woolfson ◽  
Isla RM Barnard ◽  
Andrew Morton ◽  
Becky Casement ◽  
...  
Keyword(s):  
Stem Cell ◽  
Single Molecule ◽  
Muscle Activation ◽  
Cardiac Tissue ◽  
Frequency Comb ◽  
Cardiac Cells ◽  
Optical Recording ◽  
Cardiac Contraction

AbstractCardiac regeneration and stem cell therapies depend critically on the ability to locally resolve the contractile properties of heart tissue1,2. Current regeneration approaches explore the growth of cardiac tissue in vitro and the injection of stem cell-derived cardiomyocytes3–6 (CMs) but scientists struggle with low engraftment rates and marginal mechanical improvements, leaving the estimated 26 million patients suffering from heart failure worldwide without effective therapy7–9. One impediment to further progress is the limited ability to functionally monitor injected cells as currently available techniques and probes lack speed and sensitivity as well as single cell specificity. Here, we introduce microscopic whispering gallery mode (WGM) lasers into beating cardiomyocytes to realize all-optical recording of transient cardiac contraction profiles with cellular resolution. The brilliant emission and high spectral sensitivity of microlasers to local changes in refractive index enable long-term tracking of individual cardiac cells, monitoring of drug administration, and accurate measurements of organ scale contractility in live zebrafish. Our study reveals changes in sarcomeric protein density as underlying factor to cardiac contraction which is of fundamental importance for understanding the mechano-biology of cardiac muscle activation. The ability to non-invasively assess functional properties of transplanted cells and engineered cardiac tissue will stimulate the development of novel translational approaches and the in vivo monitoring of physiological parameters more broadly. Likewise, the use of implanted microlasers as cardiac sensors is poised to inspire the adaptation of the most advanced optical tools known to the microresonator community, like quantum-enhanced single-molecule biosensing or frequency comb spectroscopy10.

scholarly journals Recapitulating Cardiac Structure and Function In Vitro from Simple to Complex Engineering

Micromachines ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 386
Author(s):  
Ana Santos ◽  
Yongjun Jang ◽  
Inwoo Son ◽  
Jongseong Kim ◽  
Yongdoo Park
Keyword(s):  
Tissue Engineering ◽  
Extracellular Matrix ◽  
Computational Modeling ◽  
Cardiac Tissue ◽  
Cardiac Development ◽  
Heart Tissue ◽  
Cardiac Tissue Engineering ◽  
Cardiac Cells

Cardiac tissue engineering aims to generate in vivo-like functional tissue for the study of cardiac development, homeostasis, and regeneration. Since the heart is composed of various types of cells and extracellular matrix with a specific microenvironment, the fabrication of cardiac tissue in vitro requires integrating technologies of cardiac cells, biomaterials, fabrication, and computational modeling to model the complexity of heart tissue. Here, we review the recent progress of engineering techniques from simple to complex for fabricating matured cardiac tissue in vitro. Advancements in cardiomyocytes, extracellular matrix, geometry, and computational modeling will be discussed based on a technology perspective and their use for preparation of functional cardiac tissue. Since the heart is a very complex system at multiscale levels, an understanding of each technique and their interactions would be highly beneficial to the development of a fully functional heart in cardiac tissue engineering.

scholarly journals “Empowering” Cardiac Cells via Stem Cell Derived Mitochondrial Transplantation- Does Age Matter?

2021 ◽  
Vol 22 (4) ◽  
pp. 1824
Author(s):  
Matthias Mietsch ◽  
Rabea Hinkel
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Treatment Strategies ◽  
Cardiac Cells ◽  
Aging Effects ◽  
Beneficial Effects ◽  
Micro Rnas ◽  
New Treatment

With cardiovascular diseases affecting millions of patients, new treatment strategies are urgently needed. The use of stem cell based approaches has been investigated during the last decades and promising effects have been achieved. However, the beneficial effect of stem cells has been found to being partly due to paracrine functions by alterations of their microenvironment and so an interesting field of research, the “stem- less” approaches has emerged over the last years using or altering the microenvironment, for example, via deletion of senescent cells, application of micro RNAs or by modifying the cellular energy metabolism via targeting mitochondria. Using autologous muscle-derived mitochondria for transplantations into the affected tissues has resulted in promising reports of improvements of cardiac functions in vitro and in vivo. However, since the targeted treatment group represents mainly elderly or otherwise sick patients, it is unclear whether and to what extent autologous mitochondria would exert their beneficial effects in these cases. Stem cells might represent better sources for mitochondria and could enhance the effect of mitochondrial transplantations. Therefore in this review we aim to provide an overview on aging effects of stem cells and mitochondria which might be important for mitochondrial transplantation and to give an overview on the current state in this field together with considerations worthwhile for further investigations.

Abstract 291: In Vitro Matured Human Embryonic Stem Cell-derived Cardiomyocytes Form Grafts With Enhanced Structure and Improved Electromechanical Integration in Injured Hearts

2020 ◽  
Vol 127 (Suppl_1) ◽  
Author(s):  
Wahiba Dhahri ◽  
Tamilla Sadikov Valdman ◽  
Beiping Qiang ◽  
Hassan Masoudpour ◽  
Eylul Ceylan ◽  
...  
Keyword(s):  
Stem Cell ◽  
Embryonic Stem Cell ◽  
Heart Development ◽  
Human Embryonic Stem Cell ◽  
Ex Vivo ◽  
Embryonic Stem ◽  
Cardiac Contraction ◽  
Structural And Functional Properties

Human embryonic stem cell-derived cardiomyocytes (hESC-CMs) have tremendous promise for application in cardiac repair, but their immature phenotype greatly limits their translational potential. The present study was designed to two hypotheses: 1) that previously reported methods to promote the maturation of hESC-CMs by culture on soft polydimethylsiloxane (PDMS) substrates can be upscaled to the quantities required for transplantation studies; and 2) that PDMS-matured hESC-CMs will stably engraft in injured hearts and form graft myocardium with enhanced structural and functional properties. First, we cultured hESC-CMs on either PDMS or tissue culture plastic (TCP) for 20 and 40 days, then phenotyped the resultant populations. All hESC-CMs were engineered to express the fluorescent voltage-sensitive protein ASAP1 to facilitate in vitro and in vivo electrophysiological studies. Relative to their counterparts on TCP, hESC-CMs on PDMS at both time-points exhibited increased cardiac gene expression as well as a more mature structural and electrophysiological phenotype in vitro. Single-cell transcriptomics confirmed enrichment of cardiac maturation markers including gene pathways involved in cardiac contraction, extracellular matrix organization, sarcomerogenesis, and adult heart development in PDMS versus TCP cultures. Next, we transplanted day 20 or 40 TCP vs PDMS ASAP1+ hESC-CMs into injured guinea pig hearts. Recipient hearts were later analyzed by ex vivo optical voltage mapping studies and histology. While CMs from both substrates showed similar capacity for engraftment, grafts formed with PDMS-matured myocytes had more mature structural properties including enhanced alignment, sarcomere lengths and maturation marker expression. Most importantly, graft formed with PDMS-matured myocytes showed improved electrophysiological properties including better host-graft electromechanical integration and more rapid and uniform propagation. We conclude that large quantities of matured hESC-CMs can indeed be economically produced by these methods. Moreover, PDMS-matured myocytes form large intramyocardial grafts with enhanced cardiac structure and electrical function, thereby establishing that maturation prior to transplantation meaningfully improves outcomes in vivo.

Effects of tertiary and quaternary derivatives of aminomethylenedioxyindenes on some experimental arrhythmias

1982 ◽  
Vol 60 (12) ◽  
pp. 1636-1642 ◽  
Author(s):  
Joseph J. Lynch ◽  
Ralf G. Rahwan ◽  
Richard J. Brumbaugh ◽  
Donald T. Witiak
Keyword(s):  
Cardiac Tissue ◽  
Metabolic Activation ◽  
Antiarrhythmic Activity ◽  
Cardiac Cells ◽  
Electrophysiological Properties ◽  
Calcium Dependent ◽  
Derivatives Of ◽  
Antiarrhythmic Effects

The 2-n-propyl- and 2-n-butyl-3-dimethylamino-5, 6-methylenedioxyindene hydrochlorides are intracellular calcium antagonists with coronary dilating and antiarrhythmic effects against ouabain- and calcium-induced arrhythmias. In the present study, pretreatment with these tertiary methylenedioxyindenes afforded significant protection against the calcium-dependent arrhythmias induced by chloroform in mice. On the other hand, their antiarrhythmic activity against aconitine- and metha-choline-induced arrhythmias in rats (in which calcium does not play a primary etiological role) was suggestive but not impressive. The quaternary derivative, 2-n-butyl-5, 6-methylenedioxy-3-trimethylammonium iodide, which was synthesized with the expectation of being devoid of antiarrhythmic activity owing to its exclusion from the intracellular compartment, unexpectedly demonstrated greater antiarrhythmic potency than the tertiary analogues against calcium-induced arrhythmias in rats and chloroform-induced arrhythmias in mice. Like the tertiary methylenedioxyindenes, the protective activity of the quaternary analogue against arrhythmias induced by aconitine or by methacholine in rats was suggestive but not impressive. Because of the relative inactivity of the quaternary methylenedioxyindene in vitro, it is proposed that its in vivo activity may be due either to metabolic activation or to concentration in cardiac tissue in sufficient quantity to allow diffusion into cardiac cells down a concentration gradient or to alter membrane electrophysiological properties to the extent of exerting antiarrhythmic activity.

scholarly journals Cyclophosphamide arrhythmogenicitytesting using human-induced pluripotent stem cell-derived cardiomyocytes

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
A. D. Podgurskaya ◽  
M. M. Slotvitsky ◽  
V. A. Tsvelaya ◽  
S. R. Frolova ◽  
S. G. Romanova ◽  
...  
Keyword(s):  
Stem Cell ◽  
Pluripotent Stem Cell ◽  
Cardiac Tissue ◽  
Capture Rate ◽  
Stimulus Frequency ◽  
Induced Pluripotent Stem Cell ◽  
Cellular Level ◽  
Induced Pluripotent

AbstractCyclophosphamide (CP) is an anticancer drug, an alkylating agent. Cardiotoxicity of CP is associated with one of its metabolites, acrolein, and clinical cardiotoxicity manifestations are described for cases of taking CP in high doses. Nevertheless, modern arrhythmogenicity prediction assays in vitro include evaluation of beat rhythm and rate as well as suppression of cardiac late markers after acute exposure to CP, but not its metabolites. The mechanism of CP side effects when taken at low doses (i.e., < 100 mg/kg), especially at the cellular level, remains unclear. In this study conduction properties and cytoskeleton structure of human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) obtained from a healthy donor under CP were evaluated. Arrhythmogenicity testing including characterization of 3 values: conduction velocity, maximum capture rate (MCR) measurements and number of occasions of re-entry on a standard linear obstacle was conducted and revealed MCR decrease of 25% ± 7% under CP. Also, conductivity area reduced by 34 ± 15%. No effect of CP on voltage-gated ion channels was found. Conduction changes (MCR and conductivity area decrease) are caused by exposure time-dependent alpha-actinin disruption detected both in hiPSC-CMs and neonatal ventricular cardiomyocytes in vitro. Deviation from the external stimulus frequency and appearance of non-conductive areas in cardiac tissue under CP is potentially arrhythmogenic and could develop arrhythmic effects in vivo.

scholarly journals The Future of Direct Cardiac Reprogramming: Any GMT Cocktail Variety?

2020 ◽  
Vol 21 (21) ◽  
pp. 7950
Author(s):  
Leyre López-Muneta ◽  
Josu Miranda-Arrubla ◽  
Xonia Carvajal-Vergara
Keyword(s):  
Transcription Factors ◽  
Cardiac Tissue ◽  
Sendai Virus ◽  
Direct Conversion ◽  
Myocardial Cell ◽  
Cardiac Cells ◽  
Human Cells ◽  
A Cell

Direct cardiac reprogramming has emerged as a novel therapeutic approach to treat and regenerate injured hearts through the direct conversion of fibroblasts into cardiac cells. Most studies have focused on the reprogramming of fibroblasts into induced cardiomyocytes (iCMs). The first study in which this technology was described, showed that at least a combination of three transcription factors, GATA4, MEF2C and TBX5 (GMT cocktail), was required for the reprogramming into iCMs in vitro using mouse cells. However, this was later demonstrated to be insufficient for the reprogramming of human cells and additional factors were required. Thereafter, most studies have focused on implementing reprogramming efficiency and obtaining fully reprogrammed and functional iCMs, by the incorporation of other transcription factors, microRNAs or small molecules to the original GMT cocktail. In this respect, great advances have been made in recent years. However, there is still no consensus on which of these GMT-based varieties is best, and robust and highly reproducible protocols are still urgently required, especially in the case of human cells. On the other hand, apart from CMs, other cells such as endothelial and smooth muscle cells to form new blood vessels will be fundamental for the correct reconstruction of damaged cardiac tissue. With this aim, several studies have centered on the direct reprogramming of fibroblasts into induced cardiac progenitor cells (iCPCs) able to give rise to all myocardial cell lineages. Especially interesting are reports in which multipotent and highly expandable mouse iCPCs have been obtained, suggesting that clinically relevant amounts of these cells could be created. However, as of yet, this has not been achieved with human iCPCs, and exactly what stage of maturity is appropriate for a cell therapy product remains an open question. Nonetheless, the major concern in regenerative medicine is the poor retention, survival, and engraftment of transplanted cells in the cardiac tissue. To circumvent this issue, several cell pre-conditioning approaches are currently being explored. As an alternative to cell injection, in vivo reprogramming may face fewer barriers for its translation to the clinic. This approach has achieved better results in terms of efficiency and iCMs maturity in mouse models, indicating that the heart environment can favor this process. In this context, in recent years some studies have focused on the development of safer delivery systems such as Sendai virus, Adenovirus, chemical cocktails or nanoparticles. This article provides an in-depth review of the in vitro and in vivo cardiac reprograming technology used in mouse and human cells to obtain iCMs and iCPCs, and discusses what challenges still lie ahead and what hurdles are to be overcome before results from this field can be transferred to the clinical settings.

scholarly journals Engineering Biomaterials to Guide Heart Cells for Matured Cardiac Tissue

Coatings ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 925
Author(s):  
Yongjun Jang ◽  
Yongdoo Park ◽  
Jongseong Kim
Keyword(s):  
Cardiac Tissue ◽  
Structural Integrity ◽  
Cardiac Cells ◽  
Heart Cells ◽  
Cardiac Tissues ◽  
Main Components ◽  
2D And 3D ◽  
Suitable Environment

The extracellular matrix (ECM) is needed to maintain the structural integrity of tissues and to mediate cellular dynamics. Its main components are fibrous proteins and glycosaminoglycans, which provide a suitable environment for biological functions. Thus, biomaterials with ECM-like properties have been extensively developed by modulating their key components and properties. In the field of cardiac tissue engineering, the use of biomaterials offers several advantages in that biophysical and biochemical cues can be designed to mediate cardiac cells, which is critical for maturation and regeneration. This suggests that understanding biomaterials and their use in vivo and in vitro is beneficial in terms of advancing cardiac engineering. The current review provides an overview of both natural and synthetic biomaterials and their use in cardiac engineering. In addition, we focus on different strategies to recapitulate the cardiac tissue in 2D and 3D approaches, which is an important step for the maturation of cardiac tissues toward regeneration of the adult heart.

MESENCHYMAL TNFR1 EXPRESSION PRESERVES THE COLONIC EPITHELIAL STEM CELL NICHE

2021 ◽  
Vol 27 (Supplement_1) ◽  
pp. S7-S8
Author(s):  
Safina Gadeock ◽  
Cambrian Liu ◽  
Brent Polk
Keyword(s):  
Stem Cell ◽  
Stem Cell Niche ◽  
Mesenchymal Cells ◽  
Epithelial Stem Cells ◽  
Epithelial Stem Cell ◽  
Long Term Treatment ◽  
Lgr5 Expression ◽  
Cell Niche

Abstract Tumor necrosis factor (TNF) is a highly expressed cytokine in inflammatory bowel disease (IBD). Although TNF can induce colonic epithelial dysfunction and apoptosis, recent studies suggest that TNF signalling promotes epithelial wound repair and stem cell function. Here we investigated the role of TNF receptor 1 (TNFR1) in mediating TNF’s effects on colonic epithelial stem cells, integral to mucosal healing in colitis. We demonstrate that Tnfr1-/- mice exhibit loss in Lgr5 expression (-52%, p&lt;0.02; N=6) compared to wildtype (WT) controls. However, the opposite result was found in vitro, wherein murine Tnfr1-/- colonoids demonstrated a significant increase in Lgr5 expression (66%, p&lt;0.007; N=6) compared to WT colonoids. Similarly, human colonoids treated with an anti-TNFR1 antibody also demonstrated an increase in Lgr5 expression, relative to IgG controls. To resolve the contradiction in the in vivo versus in vitro environment, we hypothesized that mesenchymal TNFR1 expression regulates the epithelial stem cell niche. To determine the relationships between these cell types, we co-cultured WT or Tnfr1-/- colonoids with WT or Tnfr1-/- colonic myofibroblasts (CMFs). We found that epithelial Lgr5 expression was significantly higher (by 52%, p&lt;0.05; N=3) when co-cultured with WT compared to TNFR1-/- myofibroblasts. The loss of TNFR1 expression in vivo increases the number of αSMA+ mesenchymal cells by nearly 56% (N=6) but considerably reduces the pericryptal PDGFRα+ cells, suggesting modifications in mesenchymal populations that contribute to the epithelial stem cell niche. Functionally, primary Tnfr1-/--CMFs displayed PI3k (p&lt;0.001; N=3) and MAPK (p&lt;0.01; N=3)-dependent increases in migration, proliferation, and differentiation, but RNA profiling demonstrated by diminished levels of stem cell niche factors, Rspo3 (-80%, p&lt;0.0001; N=6) and Wnt2b (-63%, p&lt;0.008; N=6) compared to WT-CMFs. Supplementation with 50ng recombinant Rspo3 for 5 d to Lgr5-GFP organoids co-cultured with TNFR1-/--CMFs restored Lgr5 expression to wildtype levels. Therefore, TNFR1-mediated TNF signalling in mesenchymal cells promotes their ability to support an epithelial stem cell niche. These results should motivate future studies of the stem cell niche in the context of long-term treatment with anti-TNF therapies.

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