Plasma cTnI Research Articles

Precise safety pharmacology studies of lapatinib for onco-cardiology assessed using in vivo canine models

Cancer chemotherapies have improved prognosis in cancer patients, resulting in a large and rapidly increasing number of cancer survivors. “Onco-cardiology” or “cardio-oncology” is a new discipline for addressing the unanticipated cardiac side effects of newly developed cancer drugs. Lapatinib, a tyrosine kinase inhibitor suppressing the epidermal growth factor receptor and ErbB2, has been used in advanced or metastatic breast cancer treatment. Reportedly, lapatinib has induced cardiovascular adverse events including QT-interval prolongation and heart failure. However, they have not been predicted by preclinical studies. Hence, a new method to assess the tyrosine kinase inhibitor-induced adverse effects needs to be established. Here, we intravenously administered lapatinib to halothane-anaesthetised dogs, evaluating cardiohemodynamic, electrophysiological, and echocardiographic profiles for pharmacological safety assessments. We intravenously administered lapatinib to chronic atrioventricular block beagle dogs to assess its proarrhythmic potential. The therapeutic concentration of lapatinib significantly increased total peripheral vascular resistance, QT, QTc, monophasic action potential (MAP)90(sinus), MAP90(CL400), effective refractory period, and plasma concentration of cardiac troponin I (cTnI), suggesting that lapatinib prolonged the ventricular repolarization without inducing lethal ventricular arrhythmia. Careful monitoring of plasma cTnI concentration and an electrocardiogram could be supportive biomarkers, predicting the onset of lapatinib-induced cardiovascular adverse events.

The Therapeutic Effects of Quercetin in a Canine Model of Low-dose Lipopolysaccharide-Induced Sepsis Compared with Hydrocortisone

BACKGROUND: Canine low-dose sepsis model provides a reliable setting to study innovative drugs. Li- popolysaccharides (LPS), a major constituent of bacterial outer membrane, have been demonstrated to play a critical role in the initiation of pathogenesis. Lipopolysaccharide-induced sepsis has been extensively studied in laboratory animals; but its importance has mainly remained unknown in dogs. OBJECTIVES: The aim of the present survey was to examine the effectiveness of quercetin, along with hydrocortisone on clinical and hematological alterations, and organ failure (liver and heart) in low-dose lipo- polysaccharide-induced canine sepsis model. METHODS: For this purpose, fifteen clinically healthy mixed dogs were randomly divided into three equal groups. Lipopolysaccharide (0.1 μg/kg, IV) was injected to dogs in group A (control). Group B was similar to group A, but quercetin bolus (2 mg/kg, IV, once) was injected 40 minutes after LPS injection. Group C was similar to group B; however, hydrocortisone bolus (2 mg/kg, IV, once) was administered instead of quercetin. Serum levels of glucose, total protein, albumin, alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), creatine kinase isoenzyme muscle/brain (CK-MB), lactate dehydrogenase (LDH) and cardiac troponin I (cTn-I) concentration were measured by commercial kits. RESULTS: In control group, red blood cells (RBCs), hemoglobin (Hb), and hematocrit (HCT) significant- ly decreased and serum activities of AST, ALP, LDH, CK-MB, and plasma cTn-I significantly increased (P<0.05). RBCs, Hb, and HCT significantly increased in quercetin group, compared with hydrocortisone and control groups (P<0.05). Quercetin group significantly decreased LDH, CK-MB, and cTn-I compared with hydrocortisone and control groups (P<0.05). Quercetin significantly decreased AST in comparison to control group and ALP in comparison to hydrocortisone group, also (P<0.05). CONCLUSIONS: These results suggest that quercetin protects RBCs in the early stages of sepsis and de- creases organs dysfunction (heart and liver), therefore it has a positive influence on sepsis and may be more effective than routine corticosteroid (hydrocortisone) therapy.

Effect of Ginkgo biloba Leaf Extract (EGb 761) on Changes in Haematological Parameters and Erythrocyte Osmotic Fragility in Hypotonic and Chlorpyrifos Exposed Rats

BACKGROUND: Canine low-dose sepsis model provides a reliable setting to study innovative drugs. Lipopolysaccharides (LPS), a major constituent of bacterial outer membrane, have been demonstrated to play a critical role in the initiation of pathogenesis. Lipopolysaccharide-induced sepsis has been extensively studied in laboratory animals; but its importance has mainly remained unknown in dogs. OBJECTIVES: The aim of the present survey was to examine the effectiveness of quercetin, along with hydrocortisone on clinical and hematological alterations, and organ failure (liver and heart) in low-dose lipopolysaccharide-induced canine sepsis model. METHODS: For this purpose, fifteen clinically healthy mixed dogs were randomly divided into three equal groups. Lipopolysaccharide (0.1 μg/kg, IV) was injected to dogs in group A (control). Group B was similar to group A, but quercetin bolus (2 mg/kg, IV, once) was injected 40 minutes after LPS injection. Group C was similar to group B; however, hydrocortisone bolus (2 mg/kg, IV, once) was administered instead of quercetin. Serum levels of glucose, total protein, albumin, alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), creatine kinase isoenzyme muscle/brain (CK-MB), lactate dehydrogenase (LDH) and cardiac troponin I (cTn-I) concentration were measured by commercial kits. RESULTS: In control group, red blood cells (RBCs), hemoglobin (Hb), and hematocrit (HCT) significantly decreased and serum activities of AST, ALP, LDH, CK-MB, and plasma cTn-I significantly increased (p <0.05). RBCs, Hb, and HCT significantly increased in quercetin group, compared with hydrocortisone and control groups (p <0.05). Quercetin group significantly decreased LDH, CK-MB, and cTn-I compared with hydrocortisone and control groups (p <0.05). Quercetin significantly decreased AST in comparison to control group and ALP in comparison to hydrocortisone group, also (p <0.05). CONCLUSIONS: These results suggest that quercetin protects RBCs in the early stages of sepsis and decreases organs dysfunction (heart and liver), therefore it has a positive influence on sepsis and may be more effective than routine corticosteroid (hydrocortisone) therapy.

Circadian sensitivity to the cardiac glycoside oleandrin is associated with diurnal intestinal P-glycoprotein expression

The cardiac glycoside oleandrin is a main active constituent of the botanical anti-cancer drug candidate PBI-05204, an extract of Nerium oleander. Here, we aimed to determine the circadian sensitivity of mice to oleandrin, and to investigate the role of intestinal P-gp in generating rhythmic drug toxicity. Toxicity and pharmacokinetic experiments were performed with wild-type, Bmal1iKO (intestine-specific Bmal1 knockout) and Bmal1fl/fl (control littermates of Bmal1iKO) mice. The cardiac toxicity (reflected by plasma CK-MB, LDH and cTn-I levels) varied significantly with the times of drug dosing in wild-type mice (a lower toxicity at ZT10 and more severe at ZT2/22). Dosing at ZT2 generated a higher drug exposure than ZT10, supporting a lower toxicity at ZT10. Intracellular accumulation of oleandrin (2.5–10 μM) was reduced in MDCKⅡ-MDR1 than in parental cells. MDR1 overexpression decreased the cell sensitivity to oleandrin toxicity. The net flux ratio (MDCKⅡ-MDR1 versus parental cells) was 2.9 for oleandrin. These data indicated oleandrin as a P-gp substrate. Both mdr1a mRNA and P-gp protein oscillated with the times of the day in small intestine of Bmal1fl/fl mice. Intestinal ablation of Bmal1 down-regulated mdr1a mRNA and P-gp protein, and abrogated their rhythms. Likewise, Bmal1 silencing led to down-regulated mdr1a mRNA and to a loss of its rhythmicity in serum-shocked CT26 cells. Based on luciferase reporter assays, Bmal1 regulated rhythmic mdr1a transcription through the clock output genes Hlf and E4bp4. Intestinal ablation of Bmal1 exacerbated oleandrin toxicity and enhanced drug exposure. Moreover, time dependency of toxicity and drug exposure were lost in Bmal1iKO mice. In conclusion, diurnal intestinal P-gp is a critical factor influencing daily oleandrin exposure and toxicity. Our findings have implications in minimizing oleandrin (and possibly Nerium oleander) toxicity and improving drug efficacy via dosing time optimization.

Ticagrelor Reduces Ischemia-Reperfusion Injury Through the NF-κB-Dependent Pathway in Rats.

We recently showed that ticagrelor reduced myocardial ischemia-reperfusion injury (IRI) and downregulated galectin-3 in the ischemic myocardium. This study tested the hypothesis that ticagrelor could reduce IRI through the NF-κB pathway. Rats were randomly divided into sham-operated group, placebo group (gastric administration of saline after IRI), ticagrelor group (gastric administration of ticagrelor after left anterior descending artery ligation), dextran sodium sulfate (DSS) group (DSS was added to drinking water 7 days before IRI), and DSS + ticagrelor group (DSS was added to drinking water 7 days before IRI and gastric administration of ticagrelor after left anterior descending artery ligation). Ticagrelor significantly reduced the infarct size and plasma cTnI at 3 and 7 days after IRI, significantly downregulated protein and mRNA expressions of NF-κB and galectin-3, and mRNA expressions of IL-6 and TNF-α in the ischemic area at 24 hours, 3 and 7 days after IRI. Ticagrelor also significantly decreased plasma high-sensitivity C-reactive protein and NT-proBNP levels at 24 hours and 3 days after IRI. Furthermore, pretreatment with DSS blocked the beneficial effects of ticagrelor. Our study indicates that the cardioprotective effect of ticagrelor might be partly mediated by inhibiting the NF-κB pathway in this rat model of IRI.

Irbesartan ameliorate inflammatory responses, and apoptosis induced by myocardial ischemia/reperfusion in male rats

Myocardial ischemia–reperfusion (I-R) represents a clinically relevant problem associated with thrombolysis, angioplasty and coronary bypass surgery. This study was undertaken to investigate the potential role of Irbesartan in amelioration of myocardial I/R injury induced by ligation of coronary artery (LAD) in a rat model. We are pretreated the animals with Irbesartan 3mg/kg i.p. 30 minutes before ligation of LAD. At the end of experiment (2 h of reperfusion), blood samples were collected from the heart for measurement of plasma level of cardiac troponin I (cTn-I). Compared with the sham group, levels of myocardial TNF-α, IL-1β, IL-6, MCP-1, MIP-1 alpha, and plasma cTn-I were increased (P&lt;0.05). Histologically, all rats in control group showed significant cardiac injury after I-R. Furthermore, rats in control group showed significant apoptosis. Irbesartan significantly counteract the increased in myocardium level of TNF-α, IL-1B, IL-6, MCP-1, MIP-1 alpha, plasma cTn-I and apoptotosis (P&lt;0.05). Histological analysis revealed that Irbesartan markedly reduced the severity of heart injury in the rats underwent LAD ligation procedure. We concluded that Irbesartan may ameliorate myocardial I/R injury in rats via interfering with inflammatory reactions and apoptosis which induced by I/R injury.

Head-to-head comparison of plasma cTnI concentration values measured with three high-sensitivity methods in a large Italian population of healthy volunteers and patients admitted to emergency department with acute coronary syndrome: A multi-center study

BackgroundThe study aim is to compare cTnI values measured with three high-sensitivity (hs) methods in apparently healthy volunteers and patients admitted to emergency department (ED) with acute coronary syndrome enrolled in a large multicentre study. MethodsHeparinized plasma samples were collected from 1511 apparently healthy subjects from 8 Italian clinical institutions (mean age: 51.5 years, SD: 14.1 years, range: 18–65 years, F/M ratio:0.95). All volunteers denied chronic or acute diseases and had normal values of routine laboratory tests. Moreover, 1322 heparinized plasma sample were also collected by 9 Italian clinical institutions from patients admitted to ED with clinical symptoms typical of acute coronary syndrome. The reference study laboratory assayed all plasma samples with three hs-methods: Architect hs-cTnI, Access hs-cTnI and ADVIA Centaur XPT methods. Principal Component Analysis (PCA) was also used to analyze the between-method differences among hs-cTnI assays. ResultsOn average, a between-method difference of 31.2% CV was found among the results of hs-cTnI immunoassays. ADVIA Centaur XPT method measured higher cTnI values than Architect and Access methods. Moreover, 99th percentile URL values depended not only on age and sex of reference population, but also on the statistical approach used for calculation (robust non-parametric vs bootstrap). ConclusionsDue to differences in concentrations and reference values, clinicians should be advised that plasma samples of the same patient should be measured for cTnI assay in the same laboratory. Specific clinical studies are needed to establish the most appropriate statistical approach to calculate the 99th percentile URL values for hs-cTnI methods.

Prediction value of plasma histone in prognosis of sepsis patients

To explore the value of plasma histones in predicting the prognosis of sepsis patients. The patients with sepsis admitted to intensive care unit (ICU) of Subei People's Hospital of Jiangsu Province Affiliated to Yangzhou University from May 2016 to June 2018 were enrolled as the research subjects, and healthy volunteers were selected as healthy control at the same period. The plasma levels of histones, cardiac troponin I (cTnI), N-terminal pro-brain natriuretic peptide (NT-proBNP), sequential organ failure assessment (SOFA) score, lactate (Lac), procalcitonin (PCT) on admission 24 hours, and use of vasoconstrictor agents, the length of ICU stay and ICU mortality were recorded. The patients were divided into survival group and death group according to the prognosis, and the differences of each index between the two groups were compared. Multivariate binary Logistic regression analysis was carried out to identify the independent risk factors of death. The correlation between histone and the levels of cTnI, NT-proBNP, PCT and Lac was analyzed. The value of plasma histone, cTnI, NT-proBNP, PCT and Lac in predicting the prognosis of patients was analyzed by receiver operating characteristic (ROC) curve. According to the threshold value of histone in predicting prognosis, the patients were divided into two groups, and the differences of various indicators between the two groups were compared. (1) A total of 93 sepsis patients were included, with 29 cases of ICU death, and the mortality was 31.2%. (2) Compared with the healthy control group, histones, cTnI, NT-proBNP were significant increased, besides, histones, cTnI in the death group were further increased compared with the survival group; in addition, SOFA, proportion of vasoconstrictor use were also significant higher than those in the survival group [histones (mg/L): 0.33 (0.28,0.45) vs. 0.22 (0.17,0.29), cTnI (μg/L): 0.25±0.13 vs. 0.20±0.08, SOFA: 11 (8, 12) vs. 9 (8, 11), the rate of vasopressor use: 93.1% (27/29) vs. 68.8% (44/64), all P < 0.05]. Statistically significant indicators between the two groups were included in multivariate binary Logistic regression analysis. The result showed that the independent risk factors affecting the prognosis of patients were the rate of vasopressor use [odds ratio (OR) = 5.277, P = 0.043] and the level of histone (OR = 79.244, P = 0.036). (3) The plasma histone level were positively correlated with cTnI (r = 0.577, P = 0.000), SOFA (r = 0.469, P = 0.000), NT-proBNP (r = 0.349, P = 0.001) and Lac (r = 0.357, P = 0.000), while there was no significant correlation between histone and PCT (r = 0.133, P = 0.205). (4) ROC curve analysis showed that the area under ROC curve (AUC) of histone predicting prognosis was 0.769 (P = 0.000); when the cut-off point was 0.30 mg/L, the sensitivity and specificity were 72.4% and 81.2% respectively. The AUC of SOFA score was 0.653 (P = 0.018), and the sensitivity and specificity were 58.6% and 70.3% respectively when the cut-off point was 10.50; while cTnI, NT-proBNP, Lac and PCT had little value in predicting the prognosis of patients. (5) Compared with the group with histone level lower than 0.3 mg/L, the group with histones level greater than 0.3 mg/L had higher SOFA score, more doses of vasopressor, higher cTnI, NT-proBNP, Lac and PCT levels, and higher ICU mortality [SOFA: 11 (10, 12) vs. 9 (8, 10), use of vasopressor: 84.8% (28/33) vs. 76.7% (46/60), cTnI (μg/L): 0.28 (0.19, 0.32) vs. 0.18 (0.12, 0.22), NT-proBNP (ng/L): 3 624.0 (2 800.0, 5 260.0) vs. 2 512.0 (1 361.8, 3 590.8), Lac (mmol/L): 2.25 (1.85, 3.50) vs. 1.60 (1.25, 2.35), PCT (μg/L): 2.10 (1.30, 4.03) vs. 1.60 (1.26, 2.33), ICU mortality: 48.5% (16/33) vs. 21.7% (13/60), all P < 0.05], while no statistical difference in the length of ICU stay was found. The independent risk factors for ICU mortality of sepsis patients were high histone level and the use of vasopressor. Plasma histone can be regarded as an indicator in predicting the prognosis of patients with sepsis.

Plasma miR-22-5p, miR-132-5p, and miR-150-3p Are Associated with Acute Myocardial Infarction.

Circulating microRNAs (miRNAs) are potential biomarkers for cardiovascular diseases. Our study aimed to determine whether miR-22-5p, miR-132-5p, and miR-150-3p represent novel biomarkers for acute myocardial infarction (AMI). Plasma samples were isolated from 35 AMI patients and 55 matched controls. Total RNA was extracted, and quantitative real-time PCR and ELISA were performed to investigate the expressions of miRNAs and cardiac troponin I (cTnI), respectively. We found that plasma levels of miR-22-5p and miR-150-3p were significantly higher during the early stage of AMI and their expression levels peaked earlier than cTnI. Conversely, circulating miR-132-5p was sustained at a low level during the early phase of AMI. All three circulating miRNAs were correlated with plasma cTnI levels. A receiver operating characteristic (ROC) analysis suggested that each single miRNA had considerable diagnostic efficacy for AMI. Moreover, combining the three miRNAs improved their diagnostic efficacy. Furthermore, neither heparin nor medications for coronary heart disease (CHD) affected plasma levels of miR-22-5p and miR-132-5p, but circulating miR-150-3p was downregulated by medications for CHD. We concluded that plasma miR-22-5p, miR-132-5p, and miR-150-3p may serve as candidate diagnostic biomarkers for early diagnosis of AMI. Moreover, a panel consisting of these three miRNAs may achieve a higher diagnostic value.

Correlations of Changes in Brain Natriuretic Peptide (BNP) and Cardiac Troponin I (cTnI) with Levels of C-Reactive Protein (CRP) and TNF-α in Pediatric Patients with Sepsis.

BackgroundThis study investigated the changes in plasma brain natriuretic peptide (BNP) and cardiac troponin I (cTnI) levels in pediatric patients with sepsis, and explored their relationships with serum inflammatory factors in pediatric patients.Material/MethodsA total of 120 pediatric patients with sepsis admitted to and treated at our hospital from 2013 to 2017 were divided into 4 groups: a systemic inflammatory response syndrome (SIRS) group (n=28), a sepsis group (n=35), a severe sepsis group (n=27), and a septic shock group (n=30). Plasma BNP, cTnI, and creatine kinase-MB (CK-MB) levels in pediatric patients in the 4 groups were measured, and the correlations of BNP and cTnI with plasma inflammatory factors C-reactive protein (CRP) and tumor necrosis factor-alpha (TNF-α) were investigated.ResultsThe plasma BNP and cTnI levels in pediatric patients with sepsis were significantly higher than those in the SIRS group (p<0.05). After hospitalization and treatment, levels of BNP and cTnI in pediatric patients were decreased. The concentrations of BNP and cTnI were correlated with CRP level (r=0.88 and 0.88, respectively). The associations (r value) of BNP and cTnI with TNF-α levels were 0.35 and 0.48, respectively.ConclusionsThe levels of plasma BNP and cTnI are associated with the severity of sepsis in pediatric patients, and were positively correlated with CRP and TNF-α levels, which provides a novel strategy for the early diagnosis and evaluation of sepsis in pediatric patients.

Data mining: Biological and temporal factors associated with blood cardiac troponin I concentration in a Chinese population

BackgroundCardiac troponin is the cornerstone biomarker for the diagnosis of acute myocardial infarction. The aims of this study were to evaluate the association of biological and temporal factors with plasma cardiac troponin I (cTnI) concentration in a large group of Chinese outpatients and to explore which factor (sex, age, time of blood sampling, and season of the year) had the largest influence on plasma cTnI levels. MethodsAnalytical data with outpatient cTnI results were downloaded from the laboratory information system from January 1, 2012 to September 20, 2018. All cTnI measurements were performed with a Siemens Dimension EXL automatic chemiluminescence immunoassay analyzer. A statistical method was used to strictly exclude outliers. A total of 86,381 outpatients were enrolled in the study. ResultsIn individuals over 60 years old, cTnI levels gradually increased with age in both males and females. cTnI reached its highest levels in individuals over 80 years old (0.030 μg/L in males and 0.027 μg/L in females). In individuals over 70 years old, cTnI levels were significantly higher in males than in females (P < .05). cTnI concentration varied between individuals with different times of blood sampling. In both men and women, cTnI concentrations reached a maximum at 05:00 (0.030 μg/L and 0.026 μg/L, respectively) and peaked again at 20:00 (0.029 μg/L and 0.023 μg/L, respectively). Additionally, there were significant differences in cTnI levels between the four seasons of the year (P < .05). In winter, cTnI levels were usually higher than in spring. Linear regression analysis showed that the factor “age ≥ 80” had the greatest impact on cTnI levels. ConclusionPlasma cTnI levels were significantly influenced by sex, age, time of blood sampling, and season of the year. Thus, in order to avoid incorrect identification of cTnI values as abnormal, a cTnI reference interval should be established, taking into consideration the sex and age of the individual, the time of day of blood sampling, and the season of the year.

Protective effect of insulin on myocardial ischemia-reperfusion injury in diabetic rats based on PI3K/Akt signaling pathway

Objective To study the effect of insulin on phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt) signaling pathway in diabetic rats with myocardial ischemia reperfusion injury. Methods Diabetic rats were induced by high-sugar and high-fat diet plus intraperitoneal injection of streptozotocin (40 mg/kg). They were randomly divided into diabetic sham group (group A), diabetes ischemic reperfusion group (group B), diabetes ischemic reperfusion insulin treatment group (group C) and diabetic ischemia reperfusion+ insulin Wortmaninn (PI3K inhibitors) group (group D), 10 in each group. Myocardial ischemia reperfusion model in diabetic rats: heart was exposed between the third and fourth ribs of the left chest, 2 mm from the lower edge of the left atrial ear, and 5-0 sterile suture was used to ligate the anteri-or descending coronary artery (LAD) and the great cardiac vein for 30 min, and then the perfusion was resumed for 120 min.Wortmannin (15 μg/kg) was given through femoral vein 20 min before ligation in group D, and the same amount of normal saline was given in the other 3 groups.Insulin (2 U/kg) was injected subcutaneously in group C and D 10 min before ligation, and the same amount of normal saline was injected subcutaneously in group A and group B. Plasma creatine kinase MB (CK-MB)and troponin I (cTnI) levels were measured in arterial blood after 120 min of reperfusion, and PI3K and Akt expression in myocardial tissue were detected by Western blot. Results Compared with the group A, the plasma levels of cTnI and CK-MB increased and the expressions of PI3K and phosphorylated protein kinase B (p-Akt) in myocardium decreased in the group B (P<0.05). After insulin treatment, the plasma cTnI [(0.89±0.26)μg/L], CK-MB [(9.24±3.16)μg/L] in the myocardial tissue of the group C decreased, while the expression of PI3K (0.341 8±0.03 1) and p-Akt (0.673 1±0.028) in the myocardial tissue increased (P<0.05). After insulin+ Wortmaninn administration, the plasma cTnI [(1.16±0.29)μg/L] and CK-MB [(12.57±3.01)μg/L] in the group D increased , while the expression of PI3K (0.292 7±0.036) and p-Akt (0.531 4±0.030) in the myocardial tissue decreased, with statistically significant difference (P<0.05). Conclusions Insulin can reduce serum CK-MB and cTnI levels in diabetic rats with myocardial ischemia reperfusion injury, possibly by activating PI3K/Akt signal transduction pathway, inhibiting myocardial enzyme release, and improving myocardial ischemia reperfusion injury in diabetic rats to play a protective role in myocardial cells. Key words: 1-phosphatidylinositol 3-kinase; Protein kinases; Insulin; Diabetes mellitus; Reperfusion injury; Rats

Changes in Autophagy Levels in Rat Myocardium During Exercise Preconditioning-Initiated Cardioprotective Effects.

The role of autophagy in the cardioprotection conferred by ischemic preconditioning (IPC) has been well described. This study aimed to investigate the changes in autophagy levels during the cardioprotective effects initiated by exercise preconditioning (EP).Rats were randomly divided into 4 groups: group C (control), group EP, group EE (exhaustive exercise), and group EP + EE (EP pretreatment at 0.5 hours before EE). The EP protocol included 4 periods of 10 minutes of treadmill running each at 30 m/minute with intervening 10 minute periods of rest. Hematoxylin-basic fuchsin-picric acid (HBFP) staining and plasma levels of cardiac troponin I (cTnI) were used to evaluate the ischemia-hypoxia injury in rat myocardium. Alteration levels in several autophagy proteins in the left ventricular myocardium were analyzed by Western blot. The phasic alterations of autophagy levels during EP-initiated cardioprotective phase were also examined.Compared with group C, the ischemia-hypoxia positive areas and IOD value in HBFP-staining and cTnI plasma levels increased significantly in group EE. Compared with group EE, the ischemia-hypoxia injury was markedly attenuated in group EP + EE. Compared with group C, the LC3-II/LC3-I ratio, a marker of autophagosome formation, was reduced in group EE, but the LC3-II/LC3-I ratio remained unaltered in group EP + EE. Furthermore, the LC3-II/LC3-I ratio increased significantly at 2 hours during the cardioprotective phase after EP.These results suggest that the activated autophagy level during the EP-initiated cardioprotective phase may be partly involved in the cardioprotective effects by maintaining a normal autophagy basal level during the subsequent exhaustive exercise in rat myocardium.

Sample matrix and high-sensitivity cardiac troponin I assays.

Background Manufacturers of high-sensitivity cardiac troponin (hs-cTn) assays have restricted use of what sample types or matrices are acceptable to use for measurement. Our goal was to evaluate the comparability of the Siemens ADVIA Centaur hs-cTnI assay across different matrices and under different storage conditions. Methods Three different QC-plasma matrices were evaluated for imprecision <10 ng/L. Passing-Bablok regression and difference plots were determined for cTnI concentrations spanning the reference interval (limit of quantification to male 99th-percentile: 2.5 ng/L to <60 ng/L) between serum and lithium heparin plasma, lithium heparin and EDTA plasma and between the Siemens and Abbott hs-cTnI assays. Stability at room temperature (RT) and 2-8 °C was also assessed across the three matrices. Results Over 16-weeks the SDs were ≤1.0 ng/L for QCs ranging from 5.0 to 8.3 ng/L. Across the reference interval there was excellent agreement between lithium heparin plasma and serum for the Siemens hs-cTnI assay (slope=0.98/intercept=-0.1), however, cTnI concentrations were proportionally lower in EDTA as compared to lithium heparin plasma (slope=0.90, 95% CI: 0.88-0.92). In lithium heparin plasma the Siemens hs-cTnI concentrations were higher than the Abbott hs-cTnI concentrations (slope=1.26/intercept=-0.2). Stability of cTnI in lithium heparin plasma as compared in serum and EDTA plasma appeared more labile, with decreases ≥20% in concentrations evident as early as 1-day in storage at RT. Conclusions There is excellent agreement in concentrations between lithium heparin plasma and serum with the Siemens ADVIA Centaur hs-cTnI assay; however, cTnI concentrations in EDTA plasma are lower. Reference intervals and clinical studies in EDTA plasma for the Centaur hs-cTnI assay are required before clinical use.

The effects of N-acetylcysteine on cisplatin induced cardiotoxicity.

Recent studies reported that oxidative stress is an important mechanism that contributes to cisplatin induced cardiotoxicity. In the present study, the effects of N-acetylcysteine (NAC), which is an antioxidant, on cisplatin induced cardiotoxicity were investigated in a rat model. Thirty two rats were separated into 4 equal groups: Control, NAC-250, CP (cisplatin), CP+NAC. Rats in the experimental groups were treated with a single dose of cisplatin intraperitoneally (ip) (10 mg/kg) and NAC (ip, 250 mg/kg) for 3 consecutive days. At the end of the experiment, cardiotoxicity was determined from plasma CK-MB, LDH, cTnI and cardiac myosin light chain-1 (CMLC-1) levels. In the tissue samples, total oxidant capacity (TOC), total antioxidant capacity (TAC), lipid hydroperoxide (ROOH) and thiol levels were measured. The hearts were also analyzed histopathologically. It was determined that cisplatin increased the tissue TOC, ROOH levels and decreased TAC and thiol levels. NAC administration after cisplatin treatment was observed to have ameliorated histological and functional changes in heart. In conclusion, the results of this experimental study suggested that oxidative stress had a serious effect on cisplatin cardiotoxicity, and NAC could be used as a therapeutic agent in addition to standard cisplatin treatment protocols (Tab. 3, Fig. 1, Ref. 35).

Castration induces antiapoptotic effects during myocardial regional ischemia reperfusion

Restoration of blood flow to ischemic myocardium results in the ischemia reperfusion (I/R) injury. This study was undertaken to investigate the potential role of endogenous testosterone in the regional ischemia reperfusion and apoptosis of the male rat hearts. Rats underwent surgical ligation of LAD and subjected to ischemia for 25 min and reperfusion for 40 min, and 2nd underwent surgical castration, left 3wks for recovery, then underwent surgical LAD ligation. Blood samples were collected from the heart for measurement of plasma level of cardiac troponin I (cTn-I). The hearts were harvested, and divided into 3 sections, the 1st for the measurement of cardiac apoptosis level, the 2nd homogenized for measurement of tissue (TNF-α, IL1-β, ICAM-1) and the 3rdwas fixed in 10% formalin for histological examination. Compared with the sham group, levels of tissue TNF-α &amp; IL-1β, ICAM-1 and apoptosis; plasma cTn-I were increased (P&lt;0.05) in the control group, all control group rats showed significant myocardial injury (P&lt;0.05) compared with the sham group. Castration significantly counteracts the increase in myocardial levels of TNF-α, IL-1, ICAM-1, plasma cTn-I and apoptosis (P&lt;0.05). Histological analysis revealed that castration markedly reduced (P&lt;0.05) the severity of the heart injury in the rats underwent the regional ischemia-reperfusion procedure. This study reveals that surgical castration may ameliorate regional I/R injury and apoptosis in the ischemic heart in rats.

Central nervous regulatory mechanism of myocardial ischemia-reperfusion injury in rats: excitability of neurons in hypothalamic paraventricular nucleus

Objective To evaluate the relationship between excitability of neurons in hypothalamic paraventricular nucleus(PVN) and central nervous regulatory mechanism of myocardial ischemia-reperfusion(I/R) injury in rats. Methods Clean-grade healthy adult male Sprague-Dawley rats, in which PVN catheters were successfully implanted, aged 6-8 weeks, weighing 260-300 g, were divided into 4 groups(n=6 each) using a random number table method: sham operation group(S group), myocardial I/R group(I/R group), γ-aminobutyric acid group(GABA group) and L-glutamic acid group(L-Glu group). Myocardial ischemia was induced by occlusion of the left anterior descending coronary artery for 30 min followed by 120-min reperfusion. Normal saline 2.4 μl/h was infused for 50 min via the PVN catheter starting from 10 min before ischemia in S and I/R groups. GABA 30 μmol/L and L-glutamic acid 30 μmol/L were infused for 50 min via the PVN catheter at a rate of 2.4 μl/h starting from 10 min before ischemia in GABA and L-Glu groups. The heart rate(HR) and mean arterial pressure(MAP) were recorded at 10 min before ischemia(T0), beginning of ischemia(T1), 30 min of ischemia(T2) and 120 min of reperfusion(T3). Rate-pressure product(RPP) was calculated. Blood samples were collected at T3 for determination of plasma cardiac troponin I(cTnI) concentrations by chemiluminescence assay. Rats were then sacrificed and myocardial specimens were obtained for measurement of myocardial infarct size(IS) and area at risk(AAS), and IS/AAR percentage was calculated. PVN tissues were taken to detect the expression of c-fos by Western blot. Results No myocardial infarction was found in group S, and myocardial infarction was marked in the other three groups. Compared with group S, the plasma cTnI concentrations were significantly increased, and the expression of c-fos in PVN was up-regulated in I/R, GABA and L-Glu groups(P<0.05), and MAP, HR and RPP were significantly decreased at T1-3 in I/R and GABA groups and at T3 in group L-Glu(P<0.05). Compared with group I/R, IS and IS/AAR percentage were significantly decreased, the plasma cTnI concentrations were decreased, the expression of c-fos in PVN was down-regulated, and HR, MAP and RPP were decreased at T1, 2 in group GABA, and IS and IS/AAR percentage were significantly increased, the plasma cTnI concentrations were increased, the expression of c-fos in PVN was up-regulated, and HR, MAP and RPP were increased at T1, 2 in group L-Glu(P<0.05). Conclusion Excitability of neurons in hypothalamic PVN is involved in central nervous regulatory mechanism of myocardial I/R injury in rats: decreased excitability can attenuate myocardial I/R injury and increased excitability aggravates myocardial I/R injury. Key words: Paraventricular hypothalamic nucleus; Neurons; Myocardial reperfusion injury

Changes of cardiac function in diabetic dogs

ObjectiveThis study aimed to evaluate cardiac function and compare the concentration of cardiac biomarkers including cardiac troponin I (cTnI), galectin-3 (Gal-3), and N-terminal pro B-type natriuretic peptides (NT-proBNP) in diabetic and control dogs. AnimalsThirty-nine dogs were included. The diabetic and control groups consisted of 19 and 20 dogs, respectively. MethodsPlasma cTnI, Gal-3, and NT-proBNP concentrations were measured in the diabetic and control groups. Echocardiography was performed in all dogs to evaluate cardiac structure and function. Echocardiographic values and cardiac biomarker concentrations between the two groups were compared with the Mann–Whitney U test. The p-value < 0.05 was considered statistical significance. ResultsNo evidence of cardiac structural changes was detected in diabetic dogs on two-dimensional echocardiography. The echocardiographic values of diabetic and control dogs were within reference intervals. Echocardiographic changes indicating diastolic dysfunction assessed by spectral flow Doppler echocardiography and tissue Doppler imaging were found in diabetic dogs (42.10%) compared with control dogs (10.00%; p = 0.022). Diabetic dogs with durations of diabetes mellitus > 1 year had an increased left ventricular wall thickness and echocardiographic changes suggesting diastolic dysfunction compared with those with duration of diabetes mellitus < 1 year. No evidence of systolic dysfunction was detected in diabetic dogs. No significant difference in plasma cTnI, Gal-3, and NT-proBNP concentrations was found between the two groups. ConclusionsEchocardiographic changes suggested that left ventricular diastolic dysfunction was detected in diabetic dogs without changes in the concentration of cardiac biomarkers including cTnI, Gal-3, and NT-proBNP compared with the age- and breed-matched control dogs.

Large-scale in silico identification of drugs exerting sex-specific effects in the heart

BackgroundMajor differences exist between men and women in both physiology and pathophysiology. Dissecting the underlying processes and contributing mechanisms of sex differences in health and disease represents a crucial step towards precision medicine. Considering the significant differences between men and women in the response to pharmacotherapies, our aim was to develop an in silico model able to predict sex-specific drug responses in a large-scale.MethodsFor this purpose, we focused on cardiovascular effects because of their high morbidity and mortality. Our model predicted several drugs (including acebutolol and tacrine) with significant differences in the heart between men and women. To validate the sex-specific drug responses identified by our model, acebutolol was selected to lower blood pressure in spontaneous hypertensive rats (SHR), tacrine was used to assess cardiac injury in mice and metformin as control for a non-sex-specific response.ResultsAs our model predicted, acebutolol exhibited a stronger decrease in heart rate and blood pressure in female than male SHRs. Tacrine lowered heart rate in male but not in female mice, induced higher plasma cTNI level and increased cardiac superoxide (DHE staining) generation in female than male mice, indicating stronger cardiac toxicity in female than male mice. To validate our model in humans, we employed two Chinese cohorts, which showed that among patients taking a beta-receptor blocker (metoprolol), women reached significantly lower diastolic blood pressure than men.ConclusionsWe conclude that our in silico model could be translated into clinical practice to predict sex-specific drug responses, thereby contributing towards a more appropriate medical care for both men and women.

Circulating Cardiac Troponin I Levels Measured by a Novel Highly Sensitive Assay in Acute Decompensated Heart Failure: Insights From the ASCEND-HF Trial

Circulating cardiac troponin levels (cTn), representative of myocardial injury, are commonly elevated in heart failure (HF) and related to adverse clinical events. However, whether cTn represents a spectrum of risk in HF is unclear. Baseline, 48-72-hour, and 30-day plasma cTnI was measured with the use of a new highly sensitive assay in 900 subjects with acute decompensated HF (ADHF) in ASCEND-HF. Multivariable models determined the relationship between cTnI and outcomes. The median (interquartile range) cTnI was 16.4 (9.3-31.6) ng/L at baseline, 14.1 (7.8-29.7) ng/L at 48-72 hours, and 11.6 (6.8-22.5) ng/L at 30 days. After additional adjustment for N-terminal pro-B-type natriuretic peptide (NT-proBNP) to established risk predictors, both baseline (odds ratio [OR] 1.25; P = .03) and 48-72-hour (OR 1.43; P = .001) cTnI were associated with higher risk for death or worsening HF before discharge. However, only cTnI at 30 days was associated with 180-day death (hazard ratio 1.25; P = .007). There were no curvilinear associations between changing cTnI and clinical outcomes. Circulating cTnI level was associated with clinical outcomes in ADHF, but these observations diminished with additional adjustment for NT-proBNP. Although they likely represent a spectrum of risk in ADHF, these findings question the implications of changing cTnI levels during treatment.