The need for proven disease-specific treatments for the novel pandemic coronavirus SARS-CoV-2 necessitates a worldwide search for therapeutic options. Since the SARS-CoV-2 virus shares extensive ...homology with SARS-CoV and MERS-CoV, effective therapies for SARS-CoV and MERS-CoV may also have therapeutic potential for the current COVID-19 outbreak. To identify therapeutics that might be repositioned for treatment of the SARS-CoV-2 disease COVID-19, we strategically reviewed the literature to identify existing therapeutics with evidence of efficacy for the treatment of the three coronaviruses that cause severe respiratory illness (SARS-CoV, MERS-CoV, and SARS-CoV-2). Mechanistic and in vitro analyses suggest multiple promising therapeutic options with potential for repurposing to treat patients with COVID-19. Therapeutics with particularly high potential efficacy for repurposing include camostat mesylate, remdesivir, favipiravir, tocilizumab, baricitinib, convalescent plasma, and humanized monoclonal antibodies. Camostat mesylate has shown therapeutic potential, likely by preventing viral entry into epithelial cells. In early research, the targeted antivirals remdesivir and favipiravir appear to benefit patients by decreasing viral replication; clinical trials suggest that remdesivir speeds recovery from COVID-19. Tocilizumab and baricitinib appear to improve mortality by preventing a severe cytokine storm. Convalescent plasma and humanized monoclonal antibodies offer passive immunity and decreased recovery time. This review highlights potential therapeutic options that may be repurposed to treat COVID-19 and suggests opportunities for further research.
The use of opioids to treat pain can increase the risk of long-term opioid dependency and is associated with negative patient outcomes. The objective of this study was to present the initial results ...following the implementation of Emergency-Department Alternatives to Opioids (ED-ALTO), a program that encourages the use of non-narcotic medications and procedures to treat pain in the Emergency Department (ED). We used a pre- and post-implementation study design to compare in-ED opioid utilization, as well as ED-ALTO medication and procedure use in the year before and after the program's implementation. After ED-ALTO's implementation, there was a decrease in opioid utilization in the ED and an increase in ED-ALTO medication use. Additionally, there was an increase in ED-ALTO procedure utilization and the complexity of conditions treated with ED-ALTO procedures, including the use of regional nerve blocks for shoulder dislocations and hip and rib fractures. In 8 of the 12 months following ED-ALTO's implementation, a lower proportion of patients receiving ED-ALTO procedures received an opioid, and the opioid dosage was lower compared to patients with the same diagnoses who received standard care. The continued expansion of ED-ALTO programs across the US may serve as a mechanism to reduce opioid utilization and safely and successfully treat pain in ED settings.
Ubiquitin-mediated protein degradation is necessary for both increased ventricular mass and survival signaling for compensated hypertrophy in pressure-overloaded (PO) myocardium. Another molecular ...keystone involved in the hypertrophic growth process is the mammalian target of rapamycin (mTOR), which forms two distinct functional complexes: mTORC1 that activates p70S6 kinase-1 to enhance protein synthesis and mTORC2 that activates Akt to promote cell survival. Independent studies in animal models show that rapamycin treatment that alters mTOR complexes also reduces hypertrophic growth and increases lifespan by an unknown mechanism. We tested whether the ubiquitin-mediated regulation of growth and survival in hypertrophic myocardium is linked to the mTOR pathway. For in vivo studies, right ventricle PO in rats was conducted by pulmonary artery banding; the normally loaded left ventricle served as an internal control. Rapamycin (0.75 mg/kg per day) or vehicle alone was administered intraperitoneally for 3 days or 2 wk. Immunoblot and immunofluorescence imaging showed that the level of ubiquitylated proteins in cardiomyocytes that increased following 48 h of PO was enhanced by rapamycin. Rapamycin pretreatment also significantly increased PO-induced Akt phosphorylation at S473, a finding confirmed in cardiomyocytes in vitro to be downstream of mTORC2. Analysis of prosurvival signaling in vivo showed that rapamycin increased PO-induced degradation of phosphorylated inhibitor of κB, enhanced expression of cellular inhibitor of apoptosis protein 1, and decreased active caspase-3. Long-term rapamycin treatment in 2-wk PO myocardium blunted hypertrophy, improved contractile function, and reduced caspase-3 and calpain activation. These data indicate potential cardioprotective benefits of rapamycin in PO hypertrophy.
Connective tissue growth factor (CTGF) is a fibrogenic cytokine that promotes fibrosis in various organs. In the heart, both cardiomyocytes (CM) and cardiac fibroblasts have been reported as a source ...of CTGF expression, aiding cardiac fibrosis. Although the mammalian target of rapamycin (mTOR) forms 2 distinct complexes, mTORC1 and mTORC2, and plays a central role in integrating biochemical signals for protein synthesis and cellular homeostasis, we explored its role in CTGF expression in adult feline CM. CM were stimulated with 10 μM phenylephrine (PE), 200 nM angiotensin (Ang), or 100 nM insulin for 24 hours. PE and Ang, but not insulin, caused an increase in CTGF mRNA expression with the highest expression observed with PE. Inhibition of mTOR with torin1 but not rapamycin significantly enhanced PE-stimulated CTGF expression. Furthermore, silencing of raptor and rictor using shRNA adenoviral vectors to suppress mTORC1 and mTORC2, respectively, or blocking phosphatidylinositol 3-kinase (PI3K) signaling with LY294002 (LY) or Akt signaling by dominant-negative Akt expression caused a substantial increase in PE-stimulated CTGF expression as measured by both mRNA and secreted protein levels. However, studies with dominant-negative delta isoform of protein kinase C demonstrate that delta isoform of protein kinase C is required for both agonist-induced CTGF expression and mTORC2/Akt-mediated CTGF suppression. Finally, PE-stimulated CTGF expression was accompanied with a corresponding increase in Smad3 phosphorylation and pretreatment of cells with SIS3, a Smad3 specific inhibitor, partially blocked the PE-stimulated CTGF expression. Therefore, a PI3K/mTOR/Akt axis plays a suppressive role on agonist-stimulated CTGF expression where the loss of this mechanism could be a contributing factor for the onset of cardiac fibrosis in the hypertrophying myocardium.
Our earlier work showed that mammalian target of rapamycin (mTOR) is essential to the development of various hypertrophic responses, including cardiomyocyte survival. mTOR forms two independent ...complexes, mTORC1 and mTORC2, by associating with common and distinct cellular proteins. Both complexes are sensitive to a pharmacological inhibitor, torin1, although only mTORC1 is inhibited by rapamycin. Since mTORC2 is known to mediate the activation of a prosurvival kinase, Akt, we analyzed whether mTORC2 directly mediates Akt activation or whether it requires the participation of another prosurvival kinase, PKCε (epsilon isoform of protein kinase-C). Our studies reveal that treatment of adult feline cardiomyocytes in vitro with insulin results in Akt phosphorylation at S473 for its activation which could be augmented with rapamycin but blocked by torin1. Silencing the expression of Rictor (rapamycin-insensitive companion of mTOR), an mTORC2 component, with a sh-RNA in cardiomyocytes lowers both insulin-stimulated Akt and PKCε phosphorylation. Furthermore, phosphorylation of PKCε and Akt at the critical S729 and S473 sites respectively was blocked by torin1 or Rictor knockdown but not by rapamycin, indicating that the phosphorylation at these specific sites occurs downstream of mTORC2. Additionally, expression of DN-PKCε significantly lowered the insulin-stimulated Akt S473 phosphorylation, indicating an upstream role for PKCε in the Akt activation. Biochemical analyses also revealed that PKCε was part of Rictor but not Raptor (a binding partner and component of mTORC1). Together, these studies demonstrate that mTORC2 mediates prosurvival signaling in adult cardiomyocytes where PKCε functions downstream of mTORC2 leading to Akt activation.
•Akt phosphorylation at S473 and its augmentation by rapamycin require mTORC2.•Phosphorylation of PKCε and Akt are lost following Rictor knockdown.•DN-PKCε expression blocks Akt phosphorylation.•PKCε and Akt are in complex with Rictor.•PKCε is downstream of mTORC2 and mediates Akt activation in adult cardiomyocytes.
Abstract Activation of both mTOR and its downstream target, S6K1 (p70 S6 kinase) have been implicated to affect cardiac hypertrophy. Our earlier work, in a feline model of 1–48 h pressure overload, ...demonstrated that mTOR/S6K1 activation occurred primarily through a PKC/c-Raf pathway. To further delineate the role of specific PKC isoforms on mTOR/S6K1 activation, we utilized primary cultures of adult feline cardiomyocytes in vitro and stimulated with endothelin-1 (ET-1), phenylephrine (PE), TPA, or insulin. All agonist treatments resulted in S2248 phosphorylation of mTOR and T389 and S421/T424 phosphorylation of S6K1, however only ET-1 and TPA-stimulated mTOR/S6K1 activation was abolished with infection of a dominant negative adenoviral c-Raf (DN-Raf) construct. Expression of DN-PKCε blocked ET-1-stimulated mTOR S2448 and S6K1 S421/T424 and T389 phosphorylation but had no effect on insulin-stimulated S6K1 phosphorylation. Expression of DN-PKCδ or pretreatment of cardiomyocytes with rottlerin, a PKCδ specific inhibitor, blocked both ET-1 and insulin stimulated mTOR S2448 and S6K1 T389 phosphorylation. However, treatment with Gö6976, a specific classical PKC (cPKC) inhibitor did not affect mTOR/S6K1 activation. These data indicate that: (i) PKCε is required for ET-1-stimulated T421/S424 phosphorylation of S6K1, (ii) both PKCε and PKCδ are required for ET-1-stimulated mTOR S2448 and S6K1 T389 phosphorylation, (iii) PKCδ is also required for insulin-stimulated mTOR S2448 and S6K1 T389 phosphorylation. Together, these data delineate both distinct and combinatorial roles of specific PKC isoforms on mTOR and S6K1 activation in adult cardiac myocytes following hypertrophic stimulation.
We estimated the seroprevalence of both acute and chronic HIV infection by using a random sample of emergency department (ED) patients from a region of the United States with low-to-moderate HIV ...prevalence.
This cross-sectional seroprevalence study consecutively enrolled patients aged 18 to 64 years within randomly selected sampling blocks in a Midwestern urban ED in a region of lower HIV prevalence in 2008 to 2009. Participants were compensated for providing a blood sample and health information. After de-identification, we assayed samples for HIV antibody and nucleic acid.
There were 926 participants who consented and enrolled. Overall, prevalence of undiagnosed HIV was 0.76% (95% confidence interval CI = 0.30%, 1.56%). Three participants (0.32%; 95% CI = 0.09%, 0.86%) were nucleic acid-positive but antibody-negative and 4 (0.43%; 95% CI = 0.15%, 1.02%) were antibody-positive.
Even when the absolute prevalence is low, a considerable proportion of undetected HIV cases in an ED population are acute. Identification of acute HIV in ED settings should receive increased priority.
Simulation technology has successfully improved patient safety and care quality through training and assessment of individuals, teams, and health care systems. Emergency medicine (EM) continues to be ...a leader and pioneer of simulation, including administration of simulation‐based fellowships and training programs. However, EM simulation–based research has been limited by low rates of publication and poor methodologic rigor. The Society for Academic Emergency Medicine (SAEM) Simulation Academy is leading efforts to improve the quality of scholarship generated by the EM simulation community and to foster successful research careers for future generations of EM simulationists. Through a needs assessment survey of our membership and a year‐long consensus‐based approach, we identified two main clusters of barriers to simulation‐based research: lack of protected time and dedicated resources and limited training and mentorship. As a result, we generated four position statements with implications for education, training, and research in EM simulation and as a call to action for the academic EM community. Recommendations include expansion of funding opportunities for simulation‐based research, creation of multi‐institutional simulation collaboratives, and development of mentorship and training pathways that promote rigor in design and methodology within EM simulation scholarship.
In response to an increased hemodynamic load, such as pressure or volume overload, cardiac hypertrophy ensues as an adaptive mechanism. Although hypertrophy initially maintains ventricular function, ...a yet undefined derailment in this process eventually leads to compromised function (decompensation) and eventually culminates in congestive heart failure (CHF). Therefore, determining the molecular signatures induced during compensatory growth is important to delineate specific mechanisms responsible for the transition into CHF. Compensatory growth involves multiple processes. At the cardiomyocyte level, one major event is increased protein turnover where enhanced protein synthesis is accompanied by increased removal of deleterious proteins. Many pathways that mediate protein turnover depend on a key molecule, mammalian target of rapamycin (mTOR). In pressure-overloaded myocardium, adrenergic receptors, growth factor receptors, and integrins are known to activate mTOR in a PI3K-dependent and/or independent manner with the involvement of specific PKC isoforms. mTOR, described as a sensor of a cell's nutrition and energy status, is uniquely positioned to activate pathways that regulate translation, cell size, and the ubiquitin-proteasome system (UPS) through rapamycin-sensitive and -insensitive signaling modules. The rapamycin-sensitive complex, known as mTOR complex 1 (mTORC1), consists of mTOR, rapamycin-sensitive adaptor protein of mTOR (Raptor) and mLST8 and promotes protein translation and cell size via molecules such as S6K1. The rapamycin-insensitive complex (mTORC2) consists of mTOR, mLST8, rapamycin-insensitive companion of mTOR (Rictor), mSin1 and Protor. mTORC2 regulates the actin cytoskeleton in addition to activating Akt (Protein kinase B) for the subsequent removal of proapoptotic factors via the UPS for cell survival. In this review, we discuss pathways and key targets of mTOR complexes that mediate growth and survival of hypertrophying cardiomyocytes and the therapeutic potential of mTOR inhibitor, rapamycin.
The present study was conducted to determine the magnitude and duration of ribosomal protein translation in response to pressure overload and determine if additional, paracrine events associated with ...mechanical transduction, such as integrin activation using a bioactive peptide ligand, RGD or endothelin stimulation lead to ribosomal protein translation. Polysome analysis of ventricular tissue samples obtained from an in vivo model of right-ventricular pressure overload (RVPO) showed a significant shift in the proportion of a 5′-terminal oligopyrimidine (5′-TOP) mRNA, rpL32, associated with the polysomal fraction when compared with non-5′-TOP mRNAs, β-actin and β-myosin heavy chain (β-MHC), in the early stages of the hypertrophic response (24–48 h). Furthermore, this increase in polysome-bound rpL32 mRNA was accompanied by the phosphorylation of mammalian target of rapamycin (mTOR), p70 S6 kinase (S6K1), and S6 ribosomal protein. In our in vitro studies, treatment of primary cultures of adult feline cardiomyocytes (cardiocytes) with 100 nM endothelin, 9 mM RGD, 100 nM insulin, or 100 nM TPA activated mTOR via distinct signaling pathways and resulted in an increased proportion of polysome-bound rpL32 mRNA. Pre-treatment of cardiocytes with the mTOR inhibitor rapamycin blocked the agonist-induced rpL32 mRNA mobilization to polysomes. These results show that mechanisms that regulate ribosomal biogenesis in the myocardium are dynamically sensitive to pressure overload. Furthermore, our in vitro studies indicate that distinct pathways are operational during the early course of hypertrophic growth and converge to activate mTOR resulting in the translational activation of 5′-TOP mRNA.
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