Publications by authors named "Marisa Sepulveda"

MicroRNA-150 (miR-150) is conserved between rodents and humans, is significantly downregulated during heart failure (HF), and correlates with patient outcomes. We previously reported that miR-150 is protective during myocardial infarction (MI) in part by decreasing cardiomyocyte (CM) apoptosis and that proapoptotic small proline-rich protein 1a (Sprr1a) is a direct CM target of miR-150. We also showed that Sprr1a knockdown in mice improves cardiac dysfunction and fibrosis post-MI and that Sprr1a is upregulated in pathological mouse cardiac fibroblasts (CFs) from ischemic myocardium.

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Student-run free clinics (SRFCs) serve as an important public safety-net for un- and under-insured patients. Few studies have investigated their financial impact or return of investment to the community. The aim of this study was to estimate the financial impact of the Indiana University Student Outreach Clinic (IUSOC) using national market values of medical visits and lab services in 2021.

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Noncoding RNAs (ncRNAs) play fundamental roles in cardiac development and cardiovascular diseases (CVDs), which are a major cause of morbidity and mortality. With advances in RNA sequencing technology, the focus of recent research has transitioned from studies of specific candidates to whole transcriptome analyses. Thanks to these types of studies, new ncRNAs have been identified for their implication in cardiac development and CVDs.

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The β-adrenergic receptor (βAR) is found primarily in hearts (mainly in cardiomyocytes [CMs]) and β-arrestin-mediated βAR signaling elicits cardioprotection through CM survival. We showed that microRNA-150 (miR-150) is upregulated by β-arrestin-mediated βAR signaling and that CM miR-150 inhibits maladaptive remodeling post-myocardial infarction. Here, we investigate whether miR-150 rescues cardiac dysfunction in mice bearing CM-specific abrogation of β-arrestin-mediated βAR signaling.

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Background: MicroRNA-150 (miR-150) plays a protective role in heart failure (HF). Long noncoding RNA, myocardial infarction-associated transcript (MIAT) regulates miR-150 function in vitro by direct interaction. Concurrent with miR-150 downregulation, MIAT is upregulated in failing hearts, and gain-of-function single-nucleotide polymorphisms in MIAT are associated with increased risk of myocardial infarction (MI) in humans.

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Cardiovascular diseases (CVDs) represent the foremost cause of mortality in the United States and worldwide. It is estimated that CVDs account for approximately 17.8 million deaths each year.

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MicroRNA-150 (miR-150) is downregulated in patients with multiple cardiovascular diseases and in diverse mouse models of heart failure (HF). miR-150 is significantly associated with HF severity and outcome in humans. We previously reported that miR-150 is activated by β-blocker carvedilol (Carv) and plays a protective role in the heart using a systemic miR-150 KO mouse model.

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Sepsis is associated with cardiac dysfunction, which is at least in part due to cardiomyocyte apoptosis. However, the underlying mechanisms are far from being understood. Using the colon ascendens stent peritonitis mouse model of sepsis (CASP), we examined the subcellular mechanisms that mediate sepsis-induced apoptosis.

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Article Synopsis
  • - Hypothyroidism causes changes in heart electrical activity that can lead to dangerous heart rhythms (arrhythmias), particularly influenced by high levels of thyrotropin (TSH), which is linked to worse health outcomes.
  • - Researchers created two rat models to study the effects of low and high TSH levels on the heart, using methods like electrocardiograms and measuring ionic currents in heart cells.
  • - While both hypothyroidism models showed increased calcium currents, only the primary hypothyroidism model (high TSH) had notable heart rhythm issues; TSH treatment also altered heart cell activity and decreased important potassium currents in myocytes.
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Background: It has been shown that carvedilol and its non β-blocking analog, VK-II-86, inhibit spontaneous Ca release from the sarcoplasmic reticulum (SR). The aim of this study is to determine whether carvedilol and VK-II-86 suppress ouabain-induced arrhythmogenic Ca waves and apoptosis in cardiac myocytes.

Methods and results: Rat cardiac myocytes were exposed to toxic doses of ouabain (50 µmol/L).

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Hemodynamic collapse and myocardial dysfunction are among the major causes of death in severe sepsis. The purpose of this study was to assess the role played by toll-like receptor 4 and by the NLRP3 inflammasome in the cardiac dysfunction that occurs after high-grade polymicrobial sepsis. We performed the colon ascendens stent peritonitis (CASP) surgery in Tlr4, Nlrp3, and caspase-1 mice.

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The force-frequency relationship (FFR) is an important intrinsic regulatory mechanism of cardiac contractility. However, a decrease (negative FFR) or no effect (flat FFR) on contractile force in response to an elevation of heart rate is present in the normal rat or in human heart failure. Reactive oxygen species (ROS) can act as intracellular signaling molecules activating diverse kinases as calcium-calmodulin-dependent protein kinase II (CaMKII) and p-38 MAP kinase (p-38K).

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Diabetes mellitus (DM) encompasses a multitude of secondary disorders, including heart disease. One of the most frequent and potentially life threatening disorders of DM-induced heart disease is ventricular tachycardia (VT). Here we show that toll-like receptor 2 (TLR2) and NLRP3 inflammasome activation in cardiac macrophages mediate the production of IL-1β in DM mice.

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Objectives: Sepsis is associated with cardiac contractile dysfunction attributed to alterations in Ca handling. We examined the subcellular mechanisms involved in sarcoplasmic reticulum Ca loss that mediate altered Ca handling and contractile dysfunction associated with sepsis.

Design: Randomized controlled trial.

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Tachycardia promotes cell death and cardiac remodeling, leading to congestive heart failure. However, the underlying mechanism of tachycardia- or rapid pacing (RP)-induced cell death remains unknown. Myocyte loss by apoptosis is recognized as a critical factor in the progression to heart failure and simulation of tachycardia by RP has been shown to increase the intracellular levels of at least two potentially proapoptotic molecules, Ca(2+) and reactive oxygen species (ROS).

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Background: Digitalis-induced Na(+) accumulation results in an increase in Ca(2+)(i) via the Na(+)/Ca(2+) exchanger, leading to enhanced sarcoplasmic reticulum (SR) Ca(2+) load, responsible for the positive inotropic and toxic arrhythmogenic effects of glycosides. A digitalis-induced increase in Ca(2+)(i) could also activate calcium-calmodulin kinase II (CaMKII), which has been shown to have proarrhythmic effects. Here, we investigate whether CaMKII underlies digitalis-induced arrhythmias and the subcellular mechanisms involved.

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