Acute Cardiac Dysfunction Research Articles

Modeling Cardiac Dysfunction Following Traumatic Hemorrhage Injury: Impact on Myocardial Integrity.

Cardiac dysfunction (CD) importantly contributes to mortality in trauma patients, who survive their initial injuries following successful hemostatic resuscitation. This poor outcome has been correlated with elevated biomarkers of myocardial injury, but the pathophysiology triggering this CD remains unknown. We investigated the pathophysiology of acute CD after trauma using a mouse model of trauma hemorrhage shock (THS)-induced CD with echocardiographic guidance of fluid resuscitation, to assess the THS impact on myocardial integrity and function. Mice were subjected to trauma (soft tissue and bone fracture) and different degrees of hemorrhage severity (pressure controlled ~MABP < 35 mmHg or <65 mmHg) for 1 h, to characterize the acute impact on cardiac function. In a second study, mice were subjected to trauma and hemorrhage (MABP < 35 mmHg) for 1 h, then underwent two echocardiographic-guided resuscitations to baseline stroke volume at 60 and 120 min, and were monitored up to 180 min to study the longer impact of THS following resuscitation. Naïve and sham animals were used as controls. At 60 min post-THS injury, animals showed a lower cardiac output (CO) and stroke volume (SV) and an early rise of heart fatty acid-binding protein (H-FABP = 167 ± 38 ng/ml; 90% increase from shams, 3.54 ± 3.06 ng/ml), when subjected to severe hemorrhage and injury. Despite resuscitation, these animals maintained lower CO (6 ml/min vs. 23 ml/min), lower SV (10 μl vs. 46 μl; both ~75% decreased), and higher H-FABP (levels (340 ± 115 ng/ml vs. 10.3 ± 0.2 ng/ml; all THS vs. shams, P < 0.001) at 180 min post-THS injury. Histopathological and flow-cytometry analysis of the heart confirmed an influx of circulatory leukocytes, compared to non-injured hearts. Myocardial injury was supported by an increase of troponin I and h-FABP and the widespread ultrastructural disorganization of the morphology of sarcomeres and mitochondria. DNA fragmentation and chromatin condensation driven by leakage of apoptosis-inducing factor (AIF) may suggest a mitochondria-driven progressive cell death. THS modeling in the mouse results in cardiomyocyte damage and reduced myocardial function, which mimics the cardiac dysfunction seen in trauma patients. This CD model may, therefore, provide further understanding to the mechanisms underlying CD and act as a tool for developing cardioprotective therapeutics to improve survival after injury.

Immune response mediates the cardiac damage after subarachnoid hemorrhage

Cardiac dysfunction is a common adverse effect of subarachnoid hemorrhage (SAH). Autopsy of SAH patients shows immunocyte infiltration into the heart. In this study, a SAH model of endovascular perforation was performed in adult male mice in order to test whether SAH causes cardiac dysfunction in non-primary cardiac disease young adult male mice and whether immune response mediates SAH induced cardiac and neurological deficit. Splenectomy was performed on a subpopulation of mice one week prior to induction of the SAH. Neurological functional tests, transthoracic Doppler echocardiography, immunofluorescent staining, and flow cytometry were performed to investigate neurological and cardiac function and immune/inflammatory effects of SAH in mice with or without splenectomy. We found that SAH significantly induces ventricular fibrillation and cardiac dysfunction identified by significantly reduced left ventricular ejection fraction, left ventricular fractional shortening, decreased heart rate, as well as increased macrophage and neutrophil infiltration into heart and inflammatory factor expression in the heart compared to sham control mice. SAH also induces neurological deficit, increases astrocyte and microglial activity, and inflammatory cell infiltration into brain as well as up-regulates inflammatory factor expression in the brain tissue. Splenectomy not only significantly improves neurological function, but also reduces cardiac dysfunction compared to SAH alone mice. Splenectomy in SAH mice significantly reduces inflammatory cell infiltration, and decreases NADPH oxidase-2 and macrophage chemokine protein-1 expression in heart and brain when compared to non-splenectomy SAH mice. Our data suggest that, SAH induces acute cardiac dysfunction in non-primary cardiac disease mice. Secondary immune response may play an important role in mediating brain-heart damage after SAH.

Takotsubo Cardiomyopathy-Acute Cardiac Dysfunction Associated With Neurological and Psychiatric Disorders.

Takotsubo cardiomyopathy (TTC) is an acute and reversible cardiac wall motion abnormality of the left myocardium. Although many studies focused on etiology, diagnostic and treatment of TTC, precise clinical guidelines on TTC are not available. Research revealed emotional and physical triggering factors of TTC and emphasized the association of TTC with psychiatric and particularly acute neurological disorders. Similar clinical presentation of acute coronary syndrome (ACS) and TTC patients, makes an anamnestic screening for TTC risk factors necessary. In psychiatric anamnesis affective disorders and chronic anxiety disorders are presumably for TTC. Subarachnoid hemorrhages and status epilepticus are typical acute neurological associated with a higher risk for TTC. Moreover, magnetic resonance imaging (MRI) studies reveled brain alterations of the limbic system and reduced connectivity of central autonomic nervous system structures. Diagnosis of TTC is made by elevation of cardiac enzymes, electrocardiogram (ECG) and visualization of myocardial wall motion. Major differential diagnoses like acute coronary syndrome and myocarditis are hereby in synopsis with anamnesis with respect of possible emotional and physical triggering factors of TTC ruled out. In most cases the TTC typical wall motion abnormalities resolve in weeks and therapy is only necessary in hemodynamic instable patients and if rare complications, like cardiac wall ruptures occur. Recently, the two-parted International expert consensus document on Takotsubo syndrome was published, providing a detailed characterization of TTC and allows clinicians to understand this cardiac dysfunction with a multidisciplinary view.

Cardiac dysfunction in exacerbations of chronic obstructive pulmonary disease is often not detected by electrocardiogram and chest radiographs.

Cardiac dysfunction is common in exacerbations of chronic obstructive pulmonary disease (COPD), even in patients without clinically suspected cardiac disorders. To investigate associations between electrocardiogram (ECG) and chest radiograph abnormalities and biochemical evidence of cardiac dysfunction (N-terminal pro-B-type natriuretic peptide and troponin T) in patients hospitalised with exacerbations of COPD at Waikato Hospital. Independent examiners, blinded to NT-proBNP and troponin T levels, assessed ECG for tachycardia, atrial fibrillation, ventricular hypertrophy and ischaemic changes in 389 patients and chest radiographs for signs of heart failure in 350 patients. Associations between electrocardiographic and radiographic abnormalities with at least moderate interrater agreement and cardiac biomarkers were analysed. High NT-proBNP values (>220 pmol/L) were associated with atrial fibrillation (22 vs 6%), right ventricular hypertrophy (24 vs 15%), left ventricular hypertrophy (15 vs 4%), ischaemia (59 vs 33%) and cardiomegaly (42 vs 20%). High troponin T values (>0.03ug/L or high-sensitivity >50 ng/L) were associated with tachycardia (65 vs 41%), right ventricular hypertrophy (26 vs 15%) and ischaemia (60 vs 36%). None of the electrocardiographic or radiographic abnormalities was sensitive or specific for cardiac biomarker abnormalities. Ischaemia on ECG was the best indicator for raised NT-proBNP (sensitivity 59%, specificity 67%). Tachycardia and ischaemia were the best indicators of raised troponin T (sensitivity 65 and 60%, specificity 59 and 64% respectively). ECG and chest radiograph abnormalities have poor sensitivity and specificity for diagnosing acute cardiac dysfunction in exacerbations of COPD. Cardiac biomarkers provide additional diagnostic information about acute cardiac dysfunction in exacerbations of COPD.

Three Cases of Cardiac Arrest with Massive Flecainide Intoxication Treated with Extracorporeal Assistance

Flecainide acetate is a Vaughan Williams class 1C anti-arrhythmic agent. Overdose causes severe cardiac and neurologic disturbances and carries a risk of fatality. No antidote is currently available.We present three cases of massive flecainide intoxication in which the patients were kept alive by extracorporeal circulation. Extracorporeal support in cases of flecainide intoxication is the only approach that can alleviate acute cardiac dysfunction, preserve blood flow to vital organs, and maintain liver metabolism and renal excretion of the toxin, while waiting for the improvement of cardiac function. Furthermore, clinical practice highlights that age, duration of CPR, PH, and lactate levels should not be a hindrance to decision-making, and demonstrates the positive, long-term neurologic and cardiologic outcomes that can be achieved with the use of extracorporeal assistance in the setting of severe flecainide intoxication.

RP001 hydrochloride improves neurological outcome after subarachnoid hemorrhage

Subarachnoid hemorrhage (SAH) results in neurological damage, acute cardiac damage and has a high mortality rate. Immunoresponse in the acute phase after SAH plays a key role in mediating vasospasm, edema, inflammation and neuronal damage. The S1P/S1PR pathway impacts multiple cellular functions, exerts anti-inflammatory and anti-apoptotic effects, promotes remyelination, and improves outcome in several central nervous system (CNS) diseases. RP001 hydrochloride is a novel S1PR agonist, which sequesters lymphocytes within their secondary tissues and prevents infiltration of immune cells into the CNS thereby reducing immune response. In this study, we investigated whether RP001 attenuates neuronal injury after SAH by reducing inflammation. S1PRs, specifically S1PR1, 3 not only exerts anti-inflammatory effects, but also decreases heart rate and induces atrioventricular conduction abnormalities. Therefore, we also tested whether RP001 treatment of SAH regulates cardiac functional outcome. Male adult C57BL/6 mice were subjected to SAH, and neurological function tests, echocardiography, and immunohistochemical analysis were performed. SAH induces neurological deficits and acute cardiac dysfunction compared to sham control mice. Treatment of SAH with a low-dose of RP001 induces better neurological outcome and cardiac function compared to a high-dose of RP001. Low-dose-RP001 treatment significantly decreases apoptosis, white matter damage, blood brain barrier permeability, microglial/astrocyte activation, macrophage chemokine protein-1, matrix metalloproteinase-9 and NADPH oxidase-2 expression in the brain compared to SAH control mice. Our findings indicate that low-dose of RP001 alleviates neurological damage after SAH, in part by decreasing neuroinflammation.

Cardiorenal status using amino-terminal pro–brain natriuretic peptide and cystatin C on cardiac resynchronization therapy outcomes: From the BIOCRT Study

Cardiorenal syndrome comprises a heterogeneous group of disorders characterized by acute or chronic cardiac and renal dysfunction. The purpose of this study was to determine the effect of cardiorenal status using a dual-marker strategy with amino-terminal pro-brain natriuretic peptide (NT-proBNP) and cystatin C on cardiac resynchronization therapy (CRT) outcomes. In 92 patients (age 66 ± 13 years; 80% male; left ventricular ejection fraction 26% ± 7%), NT-proBNP and cystatin C levels were measured at CRT implantation and at 1 month. NT-proBNP >1000 pg/mL and cystatin C >1 mg/L were considered high. Baseline cardiorenal patients were defined as having high NT-proBNP and cystatin C. At 1 month, CRT patients were categorized as (1) irreversible cardiorenal if cystatin C was persistently high; (2) progressive cardiorenal with transition from low to high cystatin C; (3) reversible cardiorenal with transition from high to low cystatin C; and (4) "normal" with stable low cystatin C. Outcomes were 6-month clinical and echocardiographic CRT response and 2 -year major adverse cardiovascular event (MACE). Compared to patients with low NT-proBNP and cystatin C, cardiorenal patients had >9-fold increase risk of CRT nonresponse (odds ratio uncompensated 9.0; compensated 36.4; both P ≤.004) and >6-fold risk of MACE (hazard ratio uncompensated 8.5; P=.005). Compared to "normal" and reversible patients (referent), irreversible patients had a 9-fold increase for CRT nonresponse (odds ratio 9.1; P <.001) and had >4-fold risk of MACE (adjusted hazard ratio 5.1; P <.001). Irreversible patients were most likely echocardiographic CRT nonresponders. Cardiorenal status by NT-proBNP and cystatin C can identify high-risk CRT patients, and those with both elevated concentrations have worse prognosis.

Clinical features and outcomes of patients with the cardio-renal syndrome admitting to a surgical intensive care unit

To investigate the clinical features and risk factors on outcomes of patients with cardio-renal syndrome (CRS) in surgical intensive care unit (SICU). The clinical data of the patients admitted to SICU of Peking University People's Hospital from January 1st 2017 to December 31st 2017 were analyzed retrospectively, including gender, age, severity of the disease, underlying diseases, type of CRS, precipitating factors of CRS, cardiac and renal function [cardiac troponin I (cTnI), B-type natriuretic peptide (BNP), serum creatinine (SCr), glomerular filtration rate (eGFR)], outcomes [secondary outcomes, duration of mechanical ventilation, the length of ICU stay, the length of hospital stay, 28-day mortality and hospital mortality]. Patients were grouped according to CRS classification or hospitalization prognosis, the clinical features within different CRS types were analyzed, and risk factors on outcomes of the CRS patients were analysed by Logistic regression. 86 (7.3%) of the 1 172 patients during the study period had CRS. (1) CRS clinical features: CRS 1-5 type patients accounted for 24.4% (21 cases), 1.2% (1 case), 20.9% (18 cases), 1.2% (1 case) and 52.3% (45 cases) respectively, CRS type 1, 3 and 5 were the main types (i.e. acute cardiac and renal dysfunction), while type 5 CRS was the highest (i.e. organ dysfunction caused by simultaneous involvement of cardiac and renal functions secondary to systemic diseases was the most common). Baseline BNP (Z = 11.365, P = 0.023), SCr peak (Z = 13.405, P = 0.009) and baseline eGFR (F = 2.648, P = 0.037) were significantly different within the CRS 5 types. The basic cardiac function of type 1 CRS patients was significantly worse than that of type 3 and type 5 CRS patients [baseline BNP (μg/L): 434.2 (187.0, 1 252.0) vs. 154.9 (66.4, 272.5), 268.5 (124.1, 486.6), both P < 0.05]. The basic renal function of type 3 CRS patients was significantly worse than that of type 5 CRS patients [baseline eGFR (mL/min): 71.0±30.3 vs. 88.3±29.0, P < 0.05]. The severity of acute kidney injury (AKI) in type 3 CRS patients was significantly higher than that in type 1 and type 5 CRS patients [SCr peak (μmol/L): 285.0 (171.5, 420.6) vs. 143.0 (99.5, 213.5), 189.0 (105.5, 280.5), both P < 0.01]. There were no significant differences in gender, age, department, acute physiology and chronic health evaluation II (APACHE II), intraoperative blood loss, basic cTnI and SCr levels, BNP peak, AKI staging and prognostic indicators among patients with various types of CRS. (2) Death risk analysis: 43 (50%) of the 86 CRS patients died during the hospital stay. Compared with the survival patients, CRS death patients were older [years old: 72 (57, 80) vs. 62 (50, 73)] and had higher APACHE II score [22 (17, 29) vs. 18 (15, 21)], with higher proportion of cerebrovascular disease (9.3% vs. 0). Regarding to precipitating factors of CRS, sepsis/septic shock (41.9% vs. 18.6%) and surgery stress (9.3% vs. 0) were remarkably increased in death patients. Death patients had higher cTnI and SCr peak [cTnI peak (μg/L): 1.155 (0.192, 5.125) vs. 0.122 (0.045, 0.610), SCr peak (μmol/L): 208 (143, 295) vs. 146 (101, 289)] and also high proportion of AKI stage 3 (41.9% vs. 20.9%), higher rate of secondary infection (67.4% vs. 30.2%), prolonged duration of mechanical ventilation and the length of ICU stay [hours: 179 (61, 470) vs. 37 (7, 134); days: 10 (4, 24) vs. 5 (2, 11)], with statistically significant differences (all P < 0.05). Logistic regression analysis showed that the elderly [odds ratio (OR) = 1.053, 95% confidence interval (95%CI) = 1.003-1.094, P = 0.010], high APACHE II score (OR = 1.165, 95%CI = 1.057-1.285, P = 0.002), sepsis/septic shock (OR = 4.561, 95%CI = 1.351-15.391, P = 0.014) and AKI stage 3 (OR = 5.468, 95%CI = 1.457-20.530, P = 0.012) were independent risk factors for hospital death in CRS patients. Surgical ICU patients with CRS are characterized by acute cardiac and renal dysfunction. CRS type 5 is the most common and has a high fatality rate. Age, severity of illness, sepsis/septic shock and AKI stage 3 are independent risk factors of death.

Cardiac Biomarkers: What Is and What Can Be.

Cardiac biomarkers are of great importance in the timely, accurate diagnosis and management of acute coronary syndrome as well as the prognosis. Diagnosis in the golden period is of utmost importance to institute therapy at the earliest and possibly reverse the myocardial damage. Cardiac biomarkers are also a powerful tool for triaging. Among the many biomarkers, the earliest examined were the myocardial enzymes, several myocardial proteins, peptides, and many other molecules. The latest addition to the repertoire is the microRNAs, which are stable molecules detectable in circulation. About four groups are found to be involved in regulation of circulatory system, and some show promise as specific and early markers of acute coronary syndrome and cardiac dysfunction. As in other fields of medicine, personalized precise treatment may be possible with the use of microRNAs. However, as of now, a multipronged approach, involving different markers of which troponins are necessary, seems to be the best way forward.

Induced pluripotent stem cell-derived endothelial progenitor cells attenuate ischemic acute kidney injury and cardiac dysfunction

BackgroundRenal ischemia–reperfusion (I/R) injury is a major cause of acute kidney injury (AKI), which is associated with high morbidity and mortality. AKI is a serious and costly medical condition. Effective therapy for AKI is an unmet clinical need, and molecular mechanisms underlying the interactions between an injured kidney and distant organs remain unclear. Therefore, novel therapeutic strategies should be developed.MethodsWe directed the differentiation of human induced pluripotent stem (iPS) cells into endothelial progenitor cells (iEPCs), which were then applied for treating mouse AKI. The mouse model of AKI was induced by I/R injury.ResultsWe discovered that intravenously infused iEPCs were recruited to the injured kidney, expressed the mature endothelial cell marker CD31, and replaced injured endothelial cells. Moreover, infused iEPCs produced abundant proangiogenic proteins, which entered into circulation. In AKI mice, blood urea nitrogen and plasma creatinine levels increased 2 days after I/R injury and reduced after the infusion of iEPCs. Tubular injury, cell apoptosis, and peritubular capillary rarefaction in injured kidneys were attenuated accordingly. In the AKI mice, iEPC therapy also ameliorated apoptosis of cardiomyocytes and cardiac dysfunction, as indicated by echocardiography. The therapy also ameliorated an increase in serum brain natriuretic peptide. Regarding the relevant mechanisms, indoxyl sulfate and interleukin-1β synergistically induced apoptosis of cardiomyocytes. Systemic iEPC therapy downregulated the proapoptotic protein caspase-3 and upregulated the anti-apoptotic protein Bcl-2 in the hearts of the AKI mice, possibly through the reduction of indoxyl sulfate and interleukin-1β.ConclusionsTherapy using human iPS cell-derived iEPCs provided a protective effect against ischemic AKI and remote cardiac dysfunction through the repair of endothelial cells and the attenuation of cardiomyocyte apoptosis.

Autonomic aspects of sudden unexpected death in epilepsy (SUDEP).

Sudden unexpected death in epilepsy (SUDEP) is a major cause of epilepsy-related mortality. SUDEP is highly linked to seizures, with most deaths occurring after convulsive seizures in sleep. In most cases of SUDEP, convulsive seizures appear to directly trigger catastrophic cardiorespiratory dysfunction leading to death. In the last few decades, many pathophysiological mechanisms have been proposed to explain the sequence of events leading to death. Patients with epilepsy often have underlying autonomic dysfunction, as measured by heart rate variability and other testing modalities. Additionally, seizures often trigger acute cardiac and respiratory dysfunction. While sinus tachycardia is the most common cardiac finding during seizures, asystole and malignant tachyarrhythmias may also occur. Seizures can also lead to respiratory dysfunction, including central ictal and obstructive apnea related to laryngospasm. Available data suggest that there could be underlying autonomic dysfunction, potentially related to genetic, medication, and other factors that might predispose individuals to sudden catastrophic cardio-respiratory dysfunction in the setting of a seizure, resulting in SUDEP. Further exploration of this possible link is needed. Patients with medically refractory epilepsy are at the highest risk, and adequate management via medical therapy to control convulsive seizures, or surgical intervention may decrease the SUDEP risk. Recently, many automated seizure detection systems have been developed to detect convulsive seizures, which may enable caregivers to more closely monitor individuals with epilepsy. Improved identification of seizures may be important for patients with refractory epilepsy as close supervision and timely intervention after a seizure could potentially reduce the risk of SUDEP.

Splanchnic Circulation and Intraabdominal Metabolism in Two Porcine Models of Low Cardiac Output

The impact of acute cardiac dysfunction on the gastrointestinal tract was investigated in anesthetized and instrumented pigs by sequential reductions of cardiac output (CO). Using a cardiac tamponade (n = 6) or partial inferior caval vein balloon inflation (n = 6), CO was controllably reduced for 1 h each to 75% (CO75%), 50% (CO50%), and 35% (CO35%) of the baseline value. Cardiac output in controls (n = 6) was not manipulated and maintained. Mean arterial pressure, superior mesenteric arterial blood flow, and intestinal mucosal perfusion started to decrease at CO50% in the intervention groups. The decrease in superior mesenteric arterial blood flow was non-linear and exaggerated at CO35%. Systemic, venous mesenteric, and intraperitoneal lactate concentrations increased in the intervention groups from CO50%. Global and mesenteric oxygen uptake decreased at CO35%. In conclusion, gastrointestinal metabolism became increasingly anaerobic when CO was reduced by 50%. Anaerobic gastrointestinal metabolism in low CO can be detected using intraperitoneal microdialysis.

Bromine inhalation mimics ischemia-reperfusion cardiomyocyte injury and calpain activation in rats.

Halogens are widely used, highly toxic chemicals that pose a potential threat to humans because of their abundance. Halogens such as bromine (Br2) cause severe pulmonary and systemic injuries; however, the mechanisms of their toxicity are largely unknown. Here, we demonstrated that Br2 and reactive brominated species produced in the lung and released in blood reach the heart and cause acute cardiac ultrastructural damage and dysfunction in rats. Br2-induced cardiac damage was demonstrated by acute (3-24 h) increases in circulating troponin I, heart-type fatty acid-binding protein, and NH2-terminal pro-brain natriuretic peptide. Transmission electron microscopy demonstrated acute (3-24 h) cardiac contraction band necrosis, disruption of z-disks, and mitochondrial swelling and disorganization. Echocardiography and hemodynamic analysis revealed left ventricular (LV) systolic and diastolic dysfunction at 7 days. Plasma and LV tissue had increased levels of brominated fatty acids. 2-Bromohexadecanal (Br-HDA) injected into the LV cavity of a normal rat caused acute LV enlargement with extensive disruption of the sarcomeric architecture and mitochondrial damage. There was extensive infiltration of neutrophils and increased myeloperoxidase levels in the hearts of Br2- or Br2 reactant-exposed rats. Increased bromination of sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA) and increased phosphalamban after Br2 inhalation decreased cardiac SERCA activity by 70%. SERCA inactivation was accompanied by increased Ca2+-sensitive LV calpain activity. The calpain-specific inhibitor MDL28170 administered within 1 h after exposure significantly decreased calpain activity and acute mortality. Bromine inhalation and formation of reactive brominated species caused acute cardiac injury and myocardial damage that can lead to heart failure. NEW & NOTEWORTHY The present study defines left ventricular systolic and diastolic dysfunction due to cardiac injury after bromine (Br2) inhalation. A calpain-dependent mechanism was identified as a potential mediator of cardiac ultrastructure damage. This study not only highlights the importance of monitoring acute cardiac symptoms in victims of Br2 exposure but also defines calpains as a potential target to treat Br2-induced toxicity.

Biomarkers for acute cardiorenal syndrome.

Cardiorenal syndromes are disorders of the heart and kidneys whereby dysfunction in one organ may lead to dysfunction in the other organ. Cardiorenal syndrome type I (CRS I) is defined as acute kidney injury caused by acute cardiac dysfunction such as acute decompensated heart failure and acute coronary syndrome. Traditional markers like serum creatinine may delay the diagnosis of acute kidney injury and provide limited information regarding the underlying pathophysiology in the setting of CRS I. Herein, we briefly review some emerging biomarkers, including brain natriuretic peptide, soluble ST2, angiopoietin, soluble thrombomodulin, neutrophil gelatinase-associated lipocalin, kidney injury molecule-1, cystatin C, interleukin-18 and calprotectin. These biomarkers may help early detecting, differential diagnosis, assessing disease severity and prognosis in patients with CRS I, therefore improve patient management and outcomes.

AMPK/PGC1α activation by melatonin attenuates acute doxorubicin cardiotoxicity via alleviating mitochondrial oxidative damage and apoptosis

Doxorubicin (DOX) is a highly effective anticancer anthracycline drug, but its side effects at the level of the heart has limited its widespread clinical application. Melatonin is a documented potent antioxidant, nontoxic and cardioprotective agent, and it is involved in maintaining mitochondrial homeostasis and function. The present study established acute DOX-induced cardiotoxicity models in both H9c2 cells incubated with 1 μM DOX and C57BL/6 mice treated with DOX (20 mg/kg cumulative dose). Melatonin markedly alleviated the DOX-induced acute cardiac dysfunction and myocardial injury. Both in vivo and in vitro studies verified that melatonin inhibited DOX-induced mitochondrial dysfunction and morphological disorders, apoptosis, and oxidative stress via the activation of AMPK and upregulation of PGC1α with its downstream signaling (NRF1, TFAM and UCP2). These effects were reversed by the use of AMPK siRNA or PGC1α siRNA in H9c2 cells, and were also negated by the cotreatment with AMPK inhibitor Compound C in vivo. Moreover, PGC1α knockdown was without effect on the AMPK phosphorylation induced by melatonin in the DOX treated H9c2 cells. Therefore, AMPK/PGC1α pathway activation may represent a new mechanism for melatonin exerted protection against acute DOX cardiotoxicity through preservation of mitochondrial homeostasis and alleviation of oxidative stress and apoptosis.

Aldehyde dehydrogenase 2 activation ameliorates cyclophosphamide-induced acute cardiotoxicity via detoxification of toxic aldehydes and suppression of cardiac cell death

Cyclophosphamide (CY)-induced acute cardiotoxicity is a common side effect which is dose dependent. It is reported that up to 20% of patients received high dose of CY treatment suffered from acute cardiac dysfunction. However, the effective intervention strategies and related mechanisms are still largely unknown. We aimed to investigate the effects of aldehyde dehydrogenase 2 (ALDH2), an important endogenous cardioprotective enzyme, on CY-induced acute cardiotoxicity and the underlying mechanisms. It was found that ALDH2 knockout (KO) mice were more sensitive to CY-induced acute cardiotoxicity, presenting as higher serum levels of creatine kinase-MB isoform and lactate dehydrogenase, and significantly reduced myocardial contractility compared with C57BL/6 (WT) mice. In addition, cardiac cell death, especially necrosis, was obviously increased in ALDH2 KO mice compared with WT mice after CY treatment. Furthermore, accumulation of toxic aldehydes such as acrolein and 4-HNE and reactive oxygen species (ROS) in the myocardium were significantly elevated after CY in ALDH2 KO mice. Importantly, ALDH2 activation by Alda-1 pretreatment markedly attenuated CY-induced accumulation of toxic aldehydes, cardiac cell death and cardiac dysfunction, without affecting CY's anti-tumor efficacy. In conclusion, the cardioprotective effects of ALDH2 activation against CY-induced acute cardiotoxicity are exerted via reducing toxic aldehydes accumulation and potentially interrupting the acrolein-ROS-aldehydes vicious circles, and thus alleviates myocardial cell death, without antagonizing the anti-tumor efficacy of CY. Therefore, ALDH2 might be a promising prevention and treatment target for CY-induced acute cardiotoxicity.

Factors associated with unplanned extubation in children—An analysis of causes

In patients with aneurysmal subarachnoid hemorrhage (aSAH), acute cardiac dysfunction and triple-H-therapy, can lead to hypoxemia. Our aim was to assess impact of a protocoled fluid restrictive approach on hypoxemia in these patients.We included prospectively ICU patients with aSAH admitted within 24 h after the bleed. The study was divided into 2 phases. The first phase, from January to December 2012, was designated as control group (group C). The second phase, from February 2014 to January 2015, was designated as study group (group S). Between these periods, a protocoled fluid intake approach was implemented to maintain as low as possible the cumulative fluid balances.Effective fluid restriction was obtained: at day 3 cumulative fluid balances were respectively for group C and group S, 1559 ± 2402 ml and 759 ± 1855 ml (p = 0.04); and 2211 ± 4918 ml vs 529 ± 2806 ml (p = 0.04) at day 7. We observed reduction in proportion of hypoxemic patient in group S compared to group C, at day 3 (22% vs 40%, p = 0.047) and at day 7 (28% vs 57%, p = 0.007).Fluid restrictive management of patients with aSAH decreases number of hypoxemic patients at day 3 and day 7.

Transient cardiac dysfunction but elevated cardiac and kidney biomarkers 24\xa0h following an ultra-distance running event in Mexican Tarahumara

BackgroundThe Mexican Tarahumara are accustomed to running ultra-distance races. No data exist on the acute physiological changes following ultra-distance running and physiological-biomarker associations in this population. Thus, we aimed to investigate the acute impact (≤ 24 h) on functional and biochemical changes of the cardiac muscle and biochemical changes associated with kidney function following a 63-km ultra-distance race with an altitude difference of 1800 m in Mexican Tarahumara athletes.MethodsTen Tarahumara male athletes (mean ± SD age = 29.9 ± 6.6 years) volunteered to participate in the study. VO2max was assessed by a sub-maximal step test individually calibrated combining heart rate and accelerometry. Standard transthoracic echocardiography methodology and venipuncture blood tests were carried out at four time points: pre-race, immediately post-race, 6 h, and 24 h post-race.ResultsEstimated mean VO2max was 54.5 (± 8.8) mL O2 min−1 kg−1 and average physiological activity intensity was 746 (± 143) J min−1 kg −1 (~ 11.5 METs). When compared to pre-race values, significant changes in left ventricular ejection fraction (LVEF) and LV end-diastolic volume (− 15%, p < 0.001 for both parameters), cardiac output (39%, p < 0.001), and maximal longitudinal velocity (− 13%, p < 0.009) were seen post-race with LVEF also being decreased at < 6 h post-race (− 8%, p < 0.014). Plasma biomarkers mid-regional pro-atrial natriuretic peptide, copeptin-ultra sensitive, and high-sensitivity cardiac troponin T remained significantly elevated at 24 h post-race, and the two latter were inversely associated with LVEF (p < 0.04). Kidney dysfunction was indicated by increased post-race copeptin-ultra sensitive.ConclusionsThe athletes participating in this study had acute transient cardiac dysfunction as assessed by echocardiography but elevated cardiac and kidney biomarkers at 24 h following a 63-km race with extreme altitude variation.

Hemodynamic effects of IV sodium nitrite in hospitalized comatose survivors of out of hospital cardiac arrest

BackgroundPatients resuscitated from cardiac arrest have brain and cardiac injury. Recent animal studies suggest that the administration of sodium nitrite after resuscitation from 12min of asystole limits acute cardiac dysfunction and improves survival and neurologic outcomes. It has been hypothesized that low doses of IV sodium nitrite given during resuscitation of out of hospital cardiac arrest (OHCA) will improve survival. Low doses of sodium nitrite (e.g., 9.6mg of sodium nitrite) are safe in healthy individuals, however the effect of nitrite on blood pressure in resuscitated cardiac arrest patients is unknown. MethodsWe performed a single-center, pilot trial of low dose sodium nitrite (1 or 9.6mg dose) vs. placebo in hospitalized out-of-hospital cardiac arrest patient to determine whether nitrite administration reduced blood pressure and whether whole blood nitrite levels increased in response to nitrite administration. ResultsThis is the first reported study of sodium nitrite in cardiac arrest patients. Infusion of low doses of sodium nitrite in comatose survivors of OHCA (n=7) compared to placebo (n=4) had no significant effects on heart rate within 30min after infusion (70±20 vs. 78±3 beats per minute, p=0.18), systolic blood pressure (103±20 vs 108±15mmHg, p=0.3), or methemoglobin levels (0.92±0.33 vs. 0.70±0.26, p=0.45). Serum nitrite levels of 2–4μM were achieved within 15min of a 9.6mg nitrite infusion. ConclusionsLow dose sodium nitrite does not cause significant hemodynamic effect in patients with OHCA, which suggests that nitrite can be delivered safely in this critically ill patient population. Higher doses of sodium nitrite are necessary in order to achieve target serum level of 10μM.

P4477Pi3kgamma inhibition rescues mice from acute cardiac contractile dysfunction, acquired long QT syndrome (acLQTS) and sudden death caused by calcineurin inhibitors

P4477Pi3kgamma inhibition rescues mice from acute cardiac contractile dysfunction, acquired long QT syndrome (acLQTS) and sudden death caused by calcineurin inhibitors