Abstract 258: Pitx2 Promotes Murine Myocardial Regeneration after Myocardial Injury

2014 ◽  
Vol 115 (suppl_1) ◽  
Author(s):  
GE TAO ◽  
Elzbieta Klysik ◽  
Yuka Morikawa ◽  
James F Martin
Keyword(s):  
Myocardial Infarction ◽  
Stem Cells ◽  
Myocardial Injury ◽  
De Novo ◽  
The United States ◽  
Myocardial Regeneration ◽  
Mouse Heart ◽  
Specific Cell ◽  
Regulation Of Transcription ◽  
Regenerative Therapy

Myocardial infarction is the leading cause of morbidity and mortality in the United States. Compromised myocardial function, due to the lack of self-renewal capacity in mature hearts, is a major reason for heart failure. Available therapies can only ameliorate, but not reverse the loss of functional myocardium. With heart transplantation as the only available cure, design of an effective regenerative therapy has become imperative for cardiovascular research. To repopulate the heart with de novo cardiomyocytes, most attempts have been based on the transplantation of cardiac, non-cardiac stem cells or their derivatives, however a more profound knowledge of stem cells is required for achieving significant progress. Meanwhile, triggering endogenous regenerative capacity is a compelling strategy for cardiac repair. It has been reported that proliferation of pre-existing cardiomyocytes strongly contributes to regeneration. Thus, efforts have been made to reintroduce mature cardiomyocytes into mitotic cycle. The mechanisms underlying the proliferation of cardiomyocytes during development and their homeostasis during adulthood are not fully understood, but likely require tight regulation of transcription factors in specific cell types. We have previously shown that the mouse Hippo kinase cascade is a major heart-size control pathway during development. In addition, activation of Yap, a transcriptional cofactor inhibited by Hippo, by genetically disrupting Hippo signaling is sufficient to induce juvenile and adult myocardial regeneration after surgery-induced myocardial infarction. Here we identified the paired-like homeodomain transcription factor 2 (pitx2) as a potential downstream target and cofactor of Yap in mouse heart. Our data indicates that Pitx2 expression is induced by myocardial injury, and is required for neonatal myocardial regeneration in a postnatal day 1 (P1) apex resection model. Further studies show that over-expression of pitx2 in adult cardiomyocytes is sufficient to promote the restoration of myocardial structure and function after myocardial infarction. Together, we show that pitx2 is a new manipulator of myocardial regeneration and could serve as a novel therapeutic target in cardiac regenerative therapy.

Abstract 350: Assessment of Clinicians’ Attitudes and Knowledge About Cardiac Troponin Testing

2020 ◽  
Vol 13 (Suppl_1) ◽  
Author(s):  
Sandeep Jain ◽  
Andrew Hammes ◽  
Eric Rudofker ◽  
Karen Ream ◽  
Andrew E Levy
Keyword(s):  
Myocardial Infarction ◽  
Cardiac Troponin ◽  
Myocardial Injury ◽  
The United States ◽  
Advanced Practice ◽  
Attitudes And Knowledge ◽  
Universal Definition ◽  
Definition Of ◽  
Attending Physicians

In the United States, the positive predictive value (PPV) of cardiac troponin for type 1 myocardial infarction is substantially lower than in Europe (15% vs. 50%). Further, even with publication of the 4 th Universal Definition of Myocardial Infarction, recent studies have shown that inaccurate classification of myocardial injury is common among clinicians in the United States. These findings are at least partly attributable to clinicians’ knowledge and attitudes about cardiac troponin testing; a survey of these parameters has never been conducted. Clinicians at the University of Colorado completed a brief 8-question multiple-choice survey related to troponin use, definitions of myocardial infarction and clinical assessment of elevated troponin levels. The survey was distributed via secure email and administered electronically using the Qualtrics™ platform. Responses were anonymous, completion was estimated to take 3 minutes and a lottery award system was used as an incentive for participation. Respondents included trainees, advanced practice providers and attending physicians from internal medicine, emergency medicine and medical subspecialties. We plan to obtain a total of 300 responses with descriptive findings of preliminary results included below. The survey was completed by 114 clinicians: 37 interns (32%), 45 residents (39%), 9 advanced practice providers (8%), 11 fellows (10%), and 12 attending physicians (11%). Regarding indications for troponin testing, 93% (106/114) indicated that they “usually” or “always” check troponin levels in patients with chest pain. More interestingly, 46% (52/112) reported checking troponin on “undifferentiated patients” at least half the time. For troponin interpretation, 97% (110/114) of participants identified that troponin levels alone cannot rule in or rule out coronary artery disease. In contrast, only 36% (41/114) and 55% (63/114), respectively, identified the NPV and PPV of a contemporary troponin assay for type 1 MI. Further, only 50% (57/114) of respondents identified that the likelihood of type 1 MI increases as troponin levels increase. Three brief clinical vignettes revealed that, while 78% (89/114) and 74% (45/61) of participants, respectively, identified type 1 MI and type 2 MI presentations, only 40% (21/53) of respondents correctly identified a vignette for non-ischemic myocardial injury. Concordant with this finding, 54% (61/114) of clinicians correctly identified the 4 th Universal Definition of Myocardial Infarction. These preliminary findings highlight important facets of clinician attitudes and knowledge about troponin testing that help explain the poor PPV for troponin and diagnostic misclassification observed among U.S. clinicians. These results could help guide curricular and clinical decision support interventions designed to improve the use and interpretation of cardiac troponin testing.

scholarly journals Analyzing Impetus of Regenerative Cellular Therapeutics in Myocardial Infarction

2020 ◽  
Vol 9 (5) ◽  
pp. 1277 ◽  
Author(s):  
Ming-Long Chang ◽  
Yu-Jui Chiu ◽  
Jian-Sing Li ◽  
Khoot-Peng Cheah ◽  
Hsiu-Hu Lin
Keyword(s):  
Myocardial Infarction ◽  
Stem Cells ◽  
Cardiac Fibroblasts ◽  
Cell Lineage ◽  
Specific Cell ◽  
Paracrine Factors ◽  
Differentiation Potential ◽  
Cell Based Therapy ◽  
Organ Specific ◽  
Made In

Both vasculature and myocardium in the heart are excessively damaged following myocardial infarction (MI), hence therapeutic strategies for treating MI hearts should concurrently aim for true cardiac repair by introducing new cardiomyocytes to replace lost or injured ones. Of them, mesenchymal stem cells (MSCs) have long been considered a promising candidate for cell-based therapy due to their unspecialized, proliferative differentiation potential to specific cell lineage and, most importantly, their capacity of secreting beneficial paracrine factors which further promote neovascularization, angiogenesis, and cell survival. As a consequence, the differentiated MSCs could multiply and replace the damaged tissues to and turn into tissue- or organ-specific cells with specialized functions. These cells are also known to release potent anti-fibrotic factors including matrix metalloproteinases, which inhibit the proliferation of cardiac fibroblasts, thereby attenuating fibrosis. To achieve the highest possible therapeutic efficacy of stem cells, the other interventions, including hydrogels, electrical stimulations, or platelet-derived biomaterials, have been supplemented, which have resulted in a narrow to broad range of outcomes. Therefore, this article comprehensively analyzed the progress made in stem cells and combinatorial therapies to rescue infarcted myocardium.

CXCR4+ CD45− Tissue-Committed Stem Cells (TCSC) for Myocardium Reside in the Bone Marrow, Are Mobilized into the Peripheral Blood during Myocardial Infarction, and “Home” to Infarcted Myocardium in CXCR4-SDF-1 and HGF/SF-c-Met Dependent Manner.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 2131-2131
Author(s):  
Magda Kucia ◽  
Buddhadeb Dawn ◽  
Yiru Guo ◽  
Greg Hunt ◽  
Marcin Wysoczynski ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Stem Cells ◽  
Bone Marrow ◽  
Peripheral Blood ◽  
Cardiac Differentiation ◽  
Specific Cell ◽  
Dependent Manner ◽  
Older Individuals ◽  
Hematopoietic Stem ◽  
Infarcted Myocardium

Abstract Several recent studies in animals as well as humans support the notion that bone marrow (BM)-derived cells participate in myocardial regeneration. However, this subject remains highly controversial and the identity of the specific cell type responsible for regeneration remains unknown. Recent work from our laboratory revealed that BM contains a highly mobile population of CXCR4+ cells that express mRNA for various markers of early tissue-committed stem cells (TCSC) and which are distinct from hematopoietic stem cells (HSC) (Leukemia2004:18;29–40). In the current study we investigated whether BM also contains a mobile pool of TCSC destined to differentiate into cardiomyocytes. Our data demonstrate that TCSC for cardiomyocytes (i) are present in significant amounts in BM harvested from young (1–2 month-old) while being barely detectable in older (1-year-old) mice; ii) reside in populations of murine BM-derived non-hematopoietic Sca-1+ CD45− cells and in population of human CXCR4+ CD34+ AC133+ CD45− BMMNC, iii) are mobilized from BM into peripheral blood (PB) during pharmacological mobilization or myocardial infarction; iv) the identified by us chemoattractants for these cells: stromal derived factor -1 (SDF-1), and hepatocyte growth factor/scatter factor (HGF/SF) are upregulated in infarcted myocardium, and v) blocking experiments with T140 (CXCR4 antagonist) and K252a (c-MET antagonist) confirmed that TCSC for cardiomyocytes are chemoattracted to the damaged myocardium in SDF-1-CXCR4 and SF/HGF-c-Met dependent manner. Thus, we conclude that the bone marrow is a potential source of TCSC for heart repair and since purified CD45+ HSC neither express cardiac markers nor differentiate in vitro into cardiomyocytes, we provide for the first time evidence that cardiac TCSC residing in bone marrow but not “plastic” HSC may account for cardiac differentiation of BM-derived cells. These observations provide rationale for further studies aimed at optimizing therapeutic cardiac regeneration by BM-derived non-hematopoietic cardiac TCSC. Finally, our observation that the number of marrow derived mobile/circulating cardiac TCSC is the highest in BM of young animals and decreases with age provides a novel insight into aging and may explain why the heart regeneration process becomes less effective in older individuals.

scholarly journals Role of Prokineticin Receptor-1 in Epicardial Progenitor Cells

2013 ◽  
Vol 1 (1) ◽  
pp. 20-31 ◽  
Author(s):  
Thu Nguyen ◽  
Adelin Gasser ◽  
Canan Nebigil
Keyword(s):  
Myocardial Infarction ◽  
Cell Fate ◽  
De Novo ◽  
Heart Function ◽  
Mouse Heart ◽  
Stem Cell Maintenance ◽  
Prokineticin 2 ◽  
Tm Domain ◽  
Definition Of

G protein-coupled receptors (GPCRs) form a large class of seven transmembrane (TM) domain receptors. The use of endogenous GPCR ligands to activate the stem cell maintenance or to direct cell differentiation would overcome many of the problems currently encountered in the use of stem cells, such as rapid in vitro differentiation and expansion or rejection in clinical applications. This review focuses on the definition of a new GPCR signaling pathway activated by peptide hormones, called “prokineticins”, in epicardium-derived cells (EPDCs). Signaling via prokineticin-2 and its receptor, PKR1, is required for cardiomyocyte survival during hypoxic stress. The binding of prokineticin-2 to PKR1 induces proliferation, migration and angiogenesis in endothelial cells. The expression of prokineticin and PKR1 increases during cardiac remodeling after myocardial infarction. Gain of function of PKR1 in the adult mouse heart revealed that cardiomyocyte-PKR1 signaling activates EPDCs in a paracrine fashion, thereby promoting de novo vasculogenesis. Transient PKR1 gene therapy after myocardial infarction in mice decreases mortality and improves heart function by promoting neovascularization, protecting cardiomyocytes and mobilizing WT1+ cells. Furthermore, PKR1 signaling promotes adult EPDC proliferation and differentiation to adopt endothelial and smooth muscle cell fate, for the induction of de novo vasculogenesis. PKR1 is expressed in the proepicardium and epicardial cells derived from mice kidneys. Loss of PKR1 causes deficits in EPDCs in the neonatal mice hearts and kidneys and impairs vascularization and heart and kidney function. Taken together, these data indicate a novel role for PKR1 in heart-kidney complex via EPDCs.

scholarly journals Estradiol Synthesis and Release in Cultured Female Rat Bone Marrow Stem Cells

2013 ◽  
Vol 2013 ◽  
pp. 1-6
Author(s):  
Dalei Zhang ◽  
Bei Yang ◽  
Weiying Zou ◽  
Xiaying Lu ◽  
Mingdi Xiong ◽  
...  
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
De Novo ◽  
Autologous Transplantation ◽  
Cell Types ◽  
Culture Conditions ◽  
Bone Marrow Stem Cells ◽  
Specific Cell ◽  
Female Rat ◽  
Alternative Source

Bone marrow stem cells (BMSCs) have the capacity to differentiate into mature cell types of multiple tissues. Thus, they represent an alternative source for organ-specific cell replacement therapy in degenerative diseases. In this study, we demonstrated that female rat BMSCs could differentiate into steroidogenic cells with the capacity forde novosynthesis of Estradiol-17β(E2) under high glucose culture conditions with or without retinoic acid (RA). The cultured BMSCs could express the mRNA and protein for P450arom, the enzyme responsible for estrogen biosynthesis. Moreover, radioimmunoassay revealed that BMSCs cultured in the present culture system produced and secreted significant amounts of testosterone, androstenedione, and E2. In addition, RA promoted E2 secretion but did not affect the levels of androgen. These results indicate that BMSCs can synthesize and release E2 and may contribute to autologous transplantation therapy for estrogen deficiency.

Abstract 192: Histological and Functional Assessment of Human Placental Stem Cells in an Induced Myocardial Infarction in Rats

2012 ◽  
Vol 111 (suppl_1) ◽  
Author(s):  
Georges Makhoul ◽  
Yu-Ting Ma ◽  
Minh Duong ◽  
Ray C J Chiu ◽  
Renzo Cecere
Keyword(s):  
Myocardial Infarction ◽  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Troponin I ◽  
Cardiac Cells ◽  
Coronary Artery Ligation ◽  
Regenerative Therapy ◽  
Age Related ◽  
Group 1

Purpose: Human bone marrow mesenchymal stem cells (hbmMSCs) have been studied extensively for myocardial regenerative therapy. However, such cells require invasive procreation and suffer from donor age-related declining quality. Recently, a more abundant resource of young MSCs has been isolated from an otherwise discarded organ: the human placenta mesenchymal stem cells (hpMSCs). In this study, we wanted to examine the survival, differentiation, and functionality of xenogeneic hpMSCs when implanted into an induced myocardial rat infarction. Methods: To inspect their stemness,hpMSCs underwent an In Vitro cardiac cell differentiation in a DMEM medium containing 5 Azacytidine. Additionally, hpMSCs were tested in a myocardial infarction animal model. Female Lewis rats (40 animals) underwent left coronary artery ligation. Animals were divided into 4 groups. Group 1 was injected with hpMSCs in the peri-infarct region. Groups 2 and 3 received hbmMSCs and In Vitro differentiated hbmMSCs into cardiomyocytes respectively. Cell free medium was injected in group 4. Echocardiography was performed at baseline, day 4, weeks 3, 6, and 9 after ligation. Myocardial tissues were harvested and studied immunohistochemically for specific muscular and cardiac markers (Actin and Troponin I) on weeks 6 and 10. Results: In Vitro differentiation into cardiomyocyte lineage was achieved with the hpMSCs. HpMSCs were detected within rat myocardium by week 6 after their implantation. These cells stained positively for Actin and Troponin I. Preliminary echocardiographic data show cardiac functional increase in group 1. Whether hpMSCs can provide a superior effect than hbmMSCs or differentiated hbmMSCs is being investigated. Conclusions: In Vitro studies indicated that the hpMSCs can be differentiated into cardiac cells. When implanted into the rat infarcted myocardium, hpMSCs survived and were able to differentiate into cardiomyocytes. These cells appeared to increase cardiac function in an induced myocardial infarction rat model. With the advantages of easy availability and young age, hpMSCs could be more suitable for myocardial regenerative therapy.

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