Plasma CK-MB Research Articles

Integrated Microbiome and Metabolome Analysis Reveals Correlations Between Gut Microbiota Components and Metabolic Profiles in Mice With Mitoxantrone-Induced Cardiotoxicity.

Mitoxantrone (MTX) is largely restricted in clinical usage due to its significant cardiotoxicity. Multiple studies have shown that an imbalance in the gut-heart axis plays an important role in the development of cardiovascular disease (CVD). We aim to explore the possible correlations between gut microbiota (GM) compositions and cardiometabolic (CM) disorder in MTX-triggered cardiotoxicity mice. MTX cumulative dose of 6 mg/kg was administered to healthy Kunming male mice to trigger cardiotoxicity, with 1 mg/kg twice weekly for a duration of 3weeks. Plasma CK-MB and LDH levels were determined, and the heart tissue histopathology was assessed, followed by utilizing an integrated liquid chromatography-mass spectrometry (LC-MS)-based heart metabolomics study alongside the 16S ribosomal RNA (rRNA) sequencing method to assess MTX impact on GM and CM profiles in mice, establishing associations between GM and CM profiles through the Pearson correlation coefficient calculation. MTX caused CK-MB and LDH level elevations and cardiotoxicity in our mouse model. MTX primarily affected the processes of protein digestion and absorption, mineral absorption, membrane transport, production of aminoacyl-transfer RNA (tRNA), metabolism of nucleotides, lipids, and amino acids, as well as autophagy. Additionally, MTX increased Romboutsia, Enterococcus, and Turicibacter abundances and lowered norank_f__Muribaculaceae, Alistipes, Odoribacter, norank_f__Lachnospiraceae, norank_f__Ruminococcaceae, norank_f__Oscillospiraceae, unclassified_f__Ruminococcaceae, NK4A214_group, Colidextribacter, norank_f__norank_o__Clostridia_vadinBB60_group, Rikenella, and Anaerotruncus abundances. The correlation analyses showcased variations in the abundance of diverse flora, such as Romboutsia, Enterococcus, Turicibacter, and norank_f__Muribaculaceae, which were related to MTX-induced cardiac injury. Our study supports the claim that MTX provokes cardiotoxicity by modifying CM and GM profiles. Our results offer new possibilities for controlling MTX-triggered cardiotoxicity.

Evaluation of Serum Levels of CK-MB in Heart Transplant Patients and Their Relationship with Graft Rejection Grades

Background: Heart transplant rejection is a multifactorial phenomenon routinely assessed using endomyocardial biopsy. Recently, efforts have been made to identify less invasive and cost-effective biomarkers for predicting graft rejection. Objectives: This study evaluated serum CK-MB levels in heart transplant patients and examined their relationship with the grading of graft rejection. Methods: In a prospective cohort study, 92 biopsy specimens from heart transplant patients were analyzed at Tehran's Rajaie Cardiovascular Medical and Research Center during 2022. Rejection grades, plasma CK-MB levels, and their relationship were investigated. Results: The mean age (standard deviation) of the patients was 36.70 (9.59) years, with 60.9% being male. Regarding graft rejection grades, 16.3% were grade 0R, 46.7% had Quilty effect (QE), 32.6% were grade 1R, and 4.3% were grade 2R. The mean (standard deviation) serum CK-MB levels for grades 0R, QE, 1R, and 2R were 17.14 (16.46), 12.39 (7.52), 26.77 (22.97), and 29.50 (7.94) ng/L, respectively (P = 0.046). The sensitivity of CK-MB for detecting grade 1R and 2R graft rejection was 56.7% and 75%, respectively, while its specificity for detecting grade 0R was 80%. A significant correlation was observed between increased serum CK-MB levels and transplant rejection grades (P < 0.001). Most cases of grade 0R had negative CK-MB serum levels (< 24 IU/L), with a higher frequency of positive CK-MB in grade 1R compared to grade 0R and in grade 2R compared to grade 1R. Conclusions: While elevated serum CK-MB levels in heart transplant patients may indicate graft rejection, the inconsistency of CK-MB levels with graft rejection grades suggests that endomyocardial biopsy and histopathological examination remain the gold standard for determining graft rejection grades.

Inhibition of Caspase-1-dependent pyroptosis alleviates myocardial ischemia/reperfusion injury during cardiopulmonary bypass (CPB) in type 2 diabetic rats

Cardiovascular complications pose a significant burden in type 2 diabetes mellitus (T2DM), driven by the intricate interplay of chronic hyperglycemia, insulin resistance, and lipid metabolism disturbances. Myocardial ischemia/reperfusion (MI/R) injury during cardiopulmonary bypass (CPB) exacerbates cardiac vulnerability. This study aims to probe the role of Caspase-1-dependent pyroptosis in global ischemia/reperfusion injury among T2DM rats undergoing CPB, elucidating the mechanisms underlying heightened myocardial injury in T2DM. This study established a rat model of T2DM and compared Mean arterial pressure (MAP), heart rate (HR), and hematocrit (Hct) between T2DM and normal rats. Myocardial cell morphology, infarction area, mitochondrial ROS and caspase-1 levels, NLRP3, pro-caspase-1, caspase-1 p10, GSDMD expressions, plasma CK-MB, cTnI, IL-1β, and IL-18 levels were assessed after reperfusion in both T2DM and normal rats. The role of Caspase-1-dependent pyroptosis in myocardial ischemia/reperfusion injury during CPB in T2DM rats was examined using the caspase-1 inhibitor VX-765 and the ROS scavenger NAC. T2DM rats demonstrated impaired glucose tolerance but stable hemodynamics during CPB, while showing heightened vulnerability to MI/R injury. This was marked by substantial lipid deposition, disrupted myocardial fibers, and intensified cellular apoptosis. The activation of caspase-1-mediated pyroptosis and increased reactive oxygen species (ROS) production further contributed to tissue damage and the ensuing inflammatory response. Notably, myocardial injury was mitigated by inhibiting caspase-1 through VX-765, which also attenuated the inflammatory cascade. Likewise, NAC treatment reduced oxidative stress and partially suppressed ROS-mediated caspase-1 activation, resulting in diminished myocardial injury. This study proved that Caspase-1-dependent pyroptosis significantly contributes to the inflammation and injury stemming from global MI/R in T2DM rats under CPB, which correlate with the surplus ROS generated by oxidative stress during reperfusion.

Integrating serum pharmacochemistry and network pharmacology to explore the molecular mechanisms of Acanthopanax senticosus (Rupr. & Maxim.) Harms on attenuating doxorubicin-induced myocardial injury

Ethnopharmacological relevanceAcanthopanax senticosus (Rupr. & Maxim.) Harms (AS), also known as Eleutherococcus senticosus (Rupr. & Maxim.) Maxim. or Siberian ginseng, has a rich history of use as an adaptogen, a substance believed to increase the body's resistance to stress, fatigue, and infectious diseases. As a traditional Chinese medicine, AS is popular for its cardioprotective effects which can protect the cardiovascular system from hazardous conditions. Doxorubicin (DOX), on the other hand, is a first-line chemotherapeutic agent against a variety of cancers, including breast cancer, lung cancer, gastric cancer, and leukemia, etc. Despite its effectiveness, the clinical use of DOX is limited by its side effects, the most serious of which is cardiotoxicity. Considering AS could be applied as an adjuvant to anticancer agents, the combination of AS and DOX might exert synergistic effects on certain malignancies with mitigated cardiotoxicity. Given this, it is necessary and meaningful to confirm whether AS would neutralize the DOX-induced cardiotoxicity and its underlying molecular mechanisms. Aim of the studyThis paper aims to validate the cardioprotective effects of AS against DOX-induced myocardial injury (MI) while deciphering the molecular mechanisms underlying such effects. Materials and methodsFirstly, the cardioprotective effects of AS against DOX-induced MI were confirmed both in vitro and in vivo. Secondly, serum pharmacochemistry and network pharmacology were orchestrated to explore the in vivo active compounds of AS and predict their ways of functioning in the treatment of DOX-induced MI. Finally, the predicted mechanisms were validated by Western blot analysis during in vivo experiments. ResultsThe results demonstrated that AS possessed excellent antioxidative ability, and could alleviate the apoptosis of H9C2 cells and the damage to mitochondria induced by DOX. In vivo experiments indicated that AS could restore the conduction abnormalities and ameliorate histopathological changes according to the electrocardiogram and cardiac morphology. Meanwhile, it markedly downregulated the inflammatory factors (TNF-α, IL-6, and IL-1β), decreased plasma ALT, AST, LDH, CK, CK-MB, and MDA levels, as well as increased SOD and GSH levels compared to the model group, which collectively substantiate the effectiveness of AS. Afterward, 14 compounds were identified from different batches of AS-dosed serum and selected for mechanism prediction through HPLC-HRMS analysis and network pharmacology. Consequently, the MAPKs and caspase cascade were confirmed as primary targets among which the interplay between the JNK/Caspase 3 feedback loop and the phosphorylation of ERK1/2 were highlighted. ConclusionsIn conclusion, the integrated approach employed in this paper illuminated the molecular mechanism of AS against DOX-induced MI, whilst providing a valuable strategy to elucidate the therapeutic effects of complicated TCM systems more reliably and efficiently.

The role and regulatory mechanism of HIF-1α in myocardial injury in rats undergoing cardiopulmonary bypass

Background Hypoxia-inducible factor-1alpha (HIF-1α) is a transcription factor implicated in physiological and pathological responses to hypoxia. The present study aims to investigate the effect and mechanism of HIF-1α on cardiopulmonary bypass (CPB)-related myocardial injury, thereby conferring a theoretical basis for the clinical treatment of myocardial injury in CPB. Methods An experimental model of CPB was established in rats by surgery. Adenovirus-packaged overexpression vectors and antiagomiRNA were used to overexpress HIF-1α and NR4A1 or inhibit miR-124-3p expression in rat myocardial tissues, respectively. qRT-PCR and Western blot detected HIF-1α, miR-124-3p, and NR4A1 expression in myocardial tissues. The rat cardiac function was monitored through an echocardiogram. The rat plasma at different stages of CPB was collected, followed by the detection of IL-6, cTnT, CK-MB, and IL-1β. TUNEL staining measured apoptosis in myocardial tissues. ChIP assay analysed the enrichment of HIF-1α on the miR-124-3p promoter. The binding relationships between HIF-1α and miR-124-3p promoter sequence and between miR-124-3p and NR4A1 3'UTR sequence were confirmed by dual-luciferase reporter assay. Results HIF-1α expression had no significant change after CPB modelling. Overexpression of HIF-1α improved the cardiac function of CPB rats, decreased plasma IL-6, cTnT, CK-MB, and IL-1β levels, and reduced TUNEL-positive myocardial cells. HIF-1α was enriched on the miR-124-3p promoter and promoted miR-124-3p expression. miR-124-3p bound to NR4A1 3'UTR sequence and targeted NR4A1 expression. Inhibition of miR-124-3p or overexpression of NR4A1 partially reversed the ameliorative effect of HIF-1α overexpression on myocardial injury in CPB rats. Conclusion Overexpression of HIF-1α can improve myocardial injury in CPB rats via the miR-124-3p/NR4A1 axis.

D-Limonene complexed with cyclodextrin attenuates cardiac arrhythmias in an experimental model of doxorubicin-induced cardiotoxicity: Possible involvement of calcium/calmodulin-dependent protein kinase type II

BackgroundArrhythmias are one manifestation of the cardiotoxicity that results from doxorubicin (Doxo) administration. Although cardiotoxicity is an anticipated outcome in anticancer therapies, there is still a lack of treatment options available for its effective management. This study sought to evaluate the possible cardioprotective effect of complex d-limonene (DL) plus hydroxypropyl-β-cyclodextrin (HβDL) during treatment with Doxo, focusing on the arrhythmic feature. MethodsCardiotoxicity was induced in Swiss mice with Doxo 20 mg/kg, with 10 mg/kg of HβDL being administered 30 min before the Doxo. Plasma CK-MB and LDH levels were analyzed. Cellular excitability and susceptibility to cardiac and cardiomyocyte arrhythmias were evaluated using in vivo (pharmacological cardiac stress) and in vitro (burst pacing) ECG protocols. Ca2+ dynamics were also investigated. The expression of CaMKII and its activation by phosphorylation and oxidation were evaluated by western blot, and molecular docking was used to analyze the possible interaction between DL and CaMKII. ResultsElectrocardiograms showed that administration of 10 mg/kg of HβDL prevented Doxo-induced widening of the QRS complex and QT interval. HβDL also prevented cardiomyocyte electrophysiological changes that trigger cellular arrhythmias, such as increases in action potential duration and variability; decreased the occurrence of delayed afterdepolarizations (DADs) and triggered activities (TAs), and reduced the incidence of arrhythmia in vivo. Ca2+ waves and CaMKII overactivation caused by phosphorylation and oxidation were also decreased. In the in silico study, DL showed potential inhibitory interaction with CaMKII. ConclusionOur results show that 10 mg/kg of βDL protects the heart against Doxo-induced cardiotoxicity arrhythmias, and that this is probably due to its inhibitory effect on CaMKII hyperactivation.

P2X7R-NEK7-NLRP3 Inflammasome Activation: A Novel Therapeutic Pathway of Qishen Granule in the Treatment of Acute Myocardial Ischemia.

BackgroundAcute myocardial ischemia (AMI) is a common heart disease with increasing morbidity and mortality year by year. Persistent and sterile inflammatory infiltration of myocardial tissue is an important factor triggering of acute myocardial ischemia secondary to acute myocardial infarction, and NLRP3 inflammasome activation is an important part of sterile inflammatory response after acute myocardial ischemia. Previous studies have shown that Qishen granule (QSG) can significantly inhibit the inflammatory injury of myocardial tissue caused by ischemia, but its effect and specific mechanism of inhibiting the activation of NLRP3 inflammasome have not been reported. This study was to investigate the specific mechanism of QSG inhibiting inflammation after AMI, and to validate the possible targets.MethodsThe myocardial ischemia model in mice was established by ligation of the left anterior descending coronary artery. Echocardiography was used to evaluate the cardiac function of the mice. Plasma CK-MB and cTnl were detected by ELISA to evaluate the degree of myocardial injury. The extent of myocardial tissue inflammation in mice was assessed by HE staining and immunohistochemistry of IL-18, IL-1β. The expressions of NLRP3, ASC, Caspase-1, and CD86 were detected by immunofluorescence; detection of key pathway proteins P2X7R, NEK7, NLRP3, ASC, Caspase-1, and effector proteins IL-18, IL-1β by Western blot. In vitro experiments, ATP+LPS was used to construct a RAW264.7 macrophage NLRP3 inflammasome activation model. Immunofluorescence and Western blot analysis were performed to detect the expression of NLRP3 pathway activator and effector proteins. Plasmid-transfected P2X7R overexpression and immunoprecipitation assays were used to evaluate the QSG-regulated NLRP3 inflammasome activation pathway.ResultsQSG rescued cardiac function and further reduced inflammatory effects in mice by inhibiting NLRP3 inflammasome activation. In vitro, QSG inhibited LPS combined with ATP-induced NLRP3 inflammasome activation in RAW264.7 macrophages by downregulating the expression of NLRP3 inflammasome key pathway proteins. In addition, inhibition or overexpression of P2X7R in RAW264.7 macrophages and immunoprecipitated protein interactions further confirmed that QSG reduces macrophages inflammasome activation via the P2X7R-NEK7-NLRP3 pathway.ConclusionP2X7R-NEK7-NLRP3 inflammasome activation is a novel therapeutic mechanism of QSG in the treatment of acute myocardial ischemia.

Evaluation of doxorubicin-induced early multi-organ toxicity in male CD1 mice by biodistribution of 18F-FDG and 67Ga-citrate. Pilot study

The search for methods that identify early toxicity, induced by chemotherapy, is urgent. Changes in the biodistribution of radiopharmaceuticals could give information on early toxicity. Ten-week-old CD1 male mice were divided into four groups. Two groups were administered a weekly dose of 5 mg/kg of doxorubicin hydrochloride (DOX) for 5 weeks and the control groups were administered saline solution. One week after the end of treatment, the biodistribution of 18F-FDG and 67Ga-citrate were carried out, as was the quantification of plasma enzymes CK, CK-MB, LDH and AST. All enzymes were higher in the treated animals, but only significant (p < 0.05) in the case of CK-MB. 18F-FDG uptake increased in all organs of treated animals except retroperitoneal fat, being significant in spleen, brain, heart, liver, lung, kidney, and inguinal fat. 67Ga-citrate had a more complex pattern. The uptake in the DOX group was higher in spleen, lung, kidney, testes, and gonadal fat, it did not change in brain, heart, and liver, and it was lower in the rest of the organs. It only showed significant differences in lung and pancreas. A thorough discussion of the possible causes that produced the change in biodistributions of both radiopharmaceuticals is included. The pilot study showed that both radiopharmaceuticals could identify early multi-organ toxicity induced by DOX. Although 18F-FDG seems to be better, 67Ga-citrato should not be ruled out a priori. The detection of early toxicity would serve to adopt treatments that prevent its progression, thus improving patient’s quality of life.

PI3K/Akt signaling pathway mediates the protective effect of endomorphin-1 postconditioning against myocardial ischemia-reperfusion injury in rats

To investigate the role of PI3K/Akt signaling pathway in mediating the protective effect of endomorphin-1 against myocardial ischemia-reperfusion (IR) injury. Fifty SD male rats were randomly divided into sham operation group, myocardial IR group, endomorphin-1 post-treatment group (EM50 group), endomorphin-1+wortmannin (a PI3K/Akt signaling pathway inhibitor) treatment group (EM50+Wort group), and wortmannin treatment group (Wort group). Rat models of myocardial IR injury were established by ligation of the left anterior descending coronary artery for 30 min followed by reperfusion for 120 min. The heart rate and mean arterial pressure were monitored during the experiment. Plasma levels of LDH, CK-MB, cTnI, IL-6, TNF-α, SOD and MDA were measured after reperfusion. The mRNA expression of Bax and Bcl-2 was detected using RT-PCR, and the expression of apoptosis-related protein cleaved caspase-3, phosphorylated Akt protein and total Akt protein in myocardial tissue was detected using Western blotting. Myocardial IR injury significantly decreased heart rate and blood pressure of the rats in comparison with the sham operation (P < 0.05). Compared with those in the IR group, the rats in EM50 group showed significantly increased heart rate and blood pressure (P < 0.05) with decreased plasma LDH, CK-MB, cTnI, IL-6, TNF-α and MDA levels (P < 0.05), increased SOD activity (P < 0.05), increased expression of p-Akt protein and Bcl-2 mRNA (P < 0.05), and decreased expression of Bax mRNA and cleaved caspase-3 protein (P < 0.05). In EM50+Wort group, the heart rate and blood pressure were significantly lowered (P < 0.05), plasma LDH, CK-MB, cTnI, IL-6, TNF-α and MDA levels increased (P < 0.05), SOD activity decreased (P < 0.05), the expression of p-Akt protein and Bcl-2 mRNA was reduced (P < 0.05), and the expression of Bax mRNA and cleaved caspase-3 protein increased (P < 0.05) as compared with those in EM50 group. EM-1 postconditioning can regulate cardiac myocyte apoptosis and reduce myocardial IR injury in rats. The PI3K/Akt signaling pathway may play a role in mediating the myocardial protective effects of EM-1 postconditioning.

Atrial Arrhythmias in Patients with Severe COVID-19

The number of confirmed COVID-19 cases has increased drastically; however, information regarding the impact of this disease on the occurrence of arrhythmias is scarce. The aim of this study was to determine the impact of COVID-19 on arrhythmia occurrence. This prospective study included patients with COVID-19 treated at the Leishenshan Temporary Hospital of Wuhan City, China, from February 24 to April 5, 2020. Demographic, comorbidity, and arrhythmias data were collected from patients with COVID-19 (n = 84) and compared with control data from patients with bacterial pneumonia (n = 84) infection. Furthermore, comparisons were made between patients with severe and nonsevere COVID-19 and between older and younger patients. Compared with patients with bacterial pneumonia, those with COVID-19 had higher total, mean, and minimum heart rates (all P < 0.01). Patients with severe COVID-19 (severe and critical type diseases) developed more atrial arrhythmias compared with those with nonsevere symptoms. Plasma creatine kinase isoenzyme (CKMB) levels (P=0.01) were higher in the severe group than in the nonsevere group, and there were more deaths in the severe group than in the nonsevere group (6 (15%) vs. 3 (2.30%); P=0.05). Premature atrial contractions (PAC) and nonsustained atrial tachycardia (NSAT) were significantly positively correlated with plasma CKMB levels but not with high-sensitive cardiac troponin I or myoglobin levels. Our data demonstrate that COVID-19 patients have higher total, mean, and minimum heart rates compared with those with bacterial pneumonia. Patients with severe or critical disease had more frequent atrial arrhythmias (including PAC and AF) and higher CKMB levels and mortality than those with nonsevere symptoms.

Evaluation of plasmatic levels of CK-MB and C-Reactive Protein in brachicephalic dogs who have narin stenosis before and after diode laser rhinoplasty

To evaluate the protective effect of rhinoplasty with diode laser on the cardiovascular system and in the reduction of the inflammatory state, CK-MB and PCR measurements were performed before and 30 days after the surgical procedure. Rhinoplasty using the diode laser promoted a significant reduction in plasma CK-MB and PCR levels, 30 days after its completion. No association was found between the pre-surgical plasma concentration of CK-MB and CRP and the degree of stenosis of the nostrils, race, age, sex and weight of the animals. A significant reduction in CK-MB was observed in dogs with severe stenosis, French Bulldog, one year old and over four years old, male and between 10 and 20 kg. Animals with severe stenosis, of the Pug breed, weighing less than 10 kg and three years of age exhibited a significant decrease in serum CRP values ​​after surgery. As a result, the degree of stenosis of the nostrils, the breed, age, sex and weight of the animals did not influence the plasma concentration of NTpro-BNP, CK-MB and PCR in brachycephalic dogs. Rhinoplasty with diode laser has been shown to be effective in reducing the plasma concentration of the natriuretic peptide CK-MB and CRP in dogs with brachycephalic syndrome, showing that the procedure has a protective effect on the cardiovascular function of these animals and is also effective in reducing inflammatory biomarkers.

Correlation between plasma myeloperoxidase and hs-troponin I, C-reactive protein and CKMB in acute coronary syndrome

Background: Acute coronary syndrome (ACS) is a group of clinical syndromes ranging from unstable angina pectoris to acute myocardial infarction (AMI) and death. Early prediction of ACS is frequently a challenging task. Myeloperoxidase is involved in oxidative stress and inflammation which plays an important role in the pathogenesis and course of ACS.Methods: The study was conducted in 30 male patients in the age group 20 - 80 years who were diagnosed as ACS and admitted to CCU. Twenty age matched normal subjects were taken as controls. Plasma MPO, hsTnI, hsCRP, CKMB, lipid parameters, urea, creatinine, glucose, AST and LDH were estimated in patients and control subjects.Results: Plasma MPO level was found to be 155.5±19.5 ng/ml and 62.4±11.8 in ACS patients and normal controls respectively and that of hsTnI was 133.3±10.1 ng/L and 20.7±1.8 ng/L, hsCRP to be 13.1±1.38 mg/L and 0.51±0.12 mg/L, CKMB to be 166.3±16.7 ng/dl and 12.8±1.51 ng/dl respectively. The values plasma of glucose, cholesterol, triglycerides, HDL-cholesterol, LDL-cholesterol, urea and creatinine were found to be slightly elevated in patients but, were not statistically significant when compared to controls. AST and LDH showed statistically significant increase in patients compared to controls. Direct linear correlation was observed between plasma MPO level and hsTnI, hsCRP and CKMB levels.Conclusions: Plasma MPO which is a predictor of early cardiovascular events and also severity of myocardial damage linearly correlates with the values of hsTnI, hsCRP and CKMB.

Circadian clock regulates metabolism and toxicity of Fuzi(lateral root of Aconitum carmichaeli Debx) in mice

BackgroundTherapeutic applications of Fuzi (lateral root of Aconitum carmichaeli Debx) are seriously concerned with its toxic effects. Strategies and approaches to reducing toxicity are of great interest. PurposeWe aimed to characterize the diurnal rhythm of Fuzi toxicity, and to determine the role of metabolism and pharmacokinetics in generating toxicity rhythmicity. MethodsToxicity was determined based on assessment of heart injury and animal survival after dosing mice with Fuzi decoction at different circadian time points. Circadian clock control of pharmacokinetics and toxicity was investigated using Bmal1-deficient (Bmal1−/−) mice. ResultsFuzi exhibited a diurnal rhythmicity in cardiotoxicity (reflected by plasma CK-MB and LDH levels). The highest level of toxicity was observed at ZT10 (5 PM), while the lowest level of toxicity occurred at ZT22 (5 AM). Also, a higher mortality rate was observed at ZT10 and lower mortality rates at other times of the day. ZT10 dosing of Fuzi generated higher systemic exposures of three toxic alkaloid ingredients aconitine (AC), hypaconitine (HA) and mesaconitine (MA) compared to ZT22. This was accompanied by reduced the formation of the metabolites (N-deethyl-AC, didemethyl-HA and 2‑hydroxyl‑MA) at ZT10. Bmal1 ablation resulted in an increased level of Fuzi toxicity at ZT22, while having no influences when drug was dosed at ZT10. As a consequence, circadian time-dependent toxicity of Fuzi was lost in Bmal1-deficient mice. In addition, Bmal1 ablation increased the plasma concentrations of AC, HA and MA in mice after oral gavage of Fuzi, and reduced formation of their metabolites (N-deethyl-AC, didemethyl-HA and 2‑hydroxyl‑MA). Moreover, Fuzi metabolism in wild-type liver microsomes was more extensive at ZT22 than at ZT10. Bmal1 ablation abrogated circadian time-dependency of hepatic Fuzi metabolism. ConclusionsFuzi chronotoxicity in mice was attributed to time-varying hepatic metabolism and systemic exposure regulated by circadian clock. The findings may have implications in reducing Fuzi toxicity with a chronotherapeutic approach.

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.

The IRE1 signaling pathway is involved in the protective effect of low-dose LPS on myocardial ischemia-reperfusion injury

AimThe IRE1 signaling pathway is implicated in I/R injury. However, little is known about the involvement of this pathway in low-dose LPS treatment of myocardial I/R injury. Thus, an attempt was made to determine the relationship between the IRE1 pathway and I/R injury using rats or in vitro H9C2 cell myocardial I/R injury models. Main methodsSprague-Dawley rats and cultured H9C2 cells were pretreated with low-dose LPS and subjected to myocardial I/R injury models. Key findingsLow-dose LPS did not affect normal rat or cellular function. Compared with the I/R group, treatment with LPS attenuated myocardial apoptosis, decreased plasma LDH and CK-MB activities, reduced myocardium infarct size, and downregulated caspase-3 expression. Moreover, the protein or mRNA expression levels of the IRE1 signaling pathway-related proteins Grp78, IRE1, p-ASK1, ASK1, p-JNK, and JNK were notably increased during I/R injury but significantly decreased by low-dose LPS treatment both in rats and in H9C2 cells. SignificanceLow-dose LPS exhibited therapeutic effects in myocardial I/R injury. Most importantly, the cardioprotective mechanism of low-dose LPS may be associated with the IRE1 signaling pathway.

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).

Cardiometabolic efficacy and toxicological evaluation of a pharmacological galanin receptor agonist

The goal of this study was to examine effects of a novel galanin receptor agonist GalR1-3 [bAla14, His15]-galanine 2-15 (G), obtained by automatic solid-phase synthesis, on the metabolic state of the area at risk and the size of acute myocardial infarction (MI) in rats in vivo and evaluate its toxicity in BALB /c mice. In anesthetized rats, regional ischemia was simulated by coronary artery occlusion and then coronary blood flow was restored. The peptide G was administered intravenously (i.v.) with a bolus after a period of regional ischemia in the dose range of 0.25-3.0 mg/kg. The sizes of MI and the activities of creatine kinase-MB (СK-MB) and lactate dehydrogenase (LDH) in blood plasma were estimated. The effect of administration of the optimal dose of G (1.0 mg/kg) on myocardial content of adenine nucleotides (AN), phosphocreatine (PCr), creatine (Cr) and lactate was studied. I.v. administration of G to rats at a dose of 1.0 mg/kg slightly affected hemodynamic parameters, but reduced MI size by 40% and decreased plasma LDH and CK-MB activity by the end of reperfusion compared to control. These effects were accompanied by a significant improvement in energy state of area at risk (AAR) - an increase in myocardial content of ATP, åAN, PCr and åCr, and combined with a decrease in myocardial lactate level compared with the control. Toxicity of peptide G was studied with a single intraperitoneal injection of 0.5-3.0% solution of the peptide substance to mice. The absence of signs of intoxication and death of animals after G injection in the maximum possible dose did not allow determining the value of the average lethal dose. The results indicate therapeutic potential of the peptide G for preventing myocardial ischemia and reperfusion injury and feasibility for further study of its pharmacological properties and mechanisms of action.

Effects of regular exercise plus food restriction on left ventricular pathological remodeling in heart failure‑induced rats.

Cardiac remodeling is the main pathophysiological process leading to heart failure. Exercise and food restriction have been shown to exert some profound physiological benefits. This study investigated the effects of exercise plus food restriction (FR) on rat left ventricular remodeling. Fifty male rats were randomly divided into 5 groups. 1) Sham (saline injection), 2) ISO (isoproterenol injection), 3) FR+ ISO (8 weeks with 60 % food restriction and then isoproterenol injection), 4) E+ISO (run-in period of 4 weeks on treadmill and then isoproterenol injection), and 5) FR+E+ISO. Serum levels of creatine kinase, nitric oxide, gene expression of microtubule-associated protein 1 light chain 3-I and II, Beclin-1, Bax and Bcl2 and TUNEL staining were investigated. ISO increased the plasma CK-MB level, gene expression of Bax and TUNEL‑positive cells in left ventricle and at the same time, decreased the serum level of NO. Regular exercise plus food restriction enhanced the expression of LC3B-II, Beclin-1, Bcl2 genes and elevated LC3B-II / LC3B-Ι, while decreasing the gene expression of Bax and TUNEL‑positive cells in the left ventricle. Our results propose that exercise plus food restriction is more effective than either therapy alone for possibly preserving cardiac internal defenses against heart failure consequences and remodeling (Tab. 2, Fig. 3, Ref. 20).

Effects of Dexmedetomidine Postconditioning on Myocardial Ischemia/Reperfusion Injury in Diabetic Rats: Role of the PI3K/Akt-Dependent Signaling Pathway.

Objective The present study was designed to determine whether dexmedetomidine (DEX) exerts cardioprotection against myocardial I/R injury in diabetic hearts and the mechanisms involved. Methods A total of 30 diabetic rats induced by high-glucose-fat diet and streptozotocin (STZ) were randomly assigned to five groups: diabetic sham-operated group (DM-S), diabetic I/R group (DM-I/R), diabetic DEX group (DM-D), diabetic DEX + Wort group (DM-DW), and diabetic Wort group (DM-W). Another 12 age-matched male normal SD rats were randomly divided into two groups: sham-operated group (S) and I/R group (I/R). All rats were subjected to 30 min myocardial ischemia followed by 120 min reperfusion except sham groups. Plasmas were collected to measure the malondialdehyde (MDA), creatine kinase isoenzymes (CK-MB), and lactate dehydrogenase (LDH) levels and superoxide dismutase (SOD) activity at the end of reperfusion. Pathologic changes in myocardial tissues were observed by H-E staining. The total and phosphorylated form of Akt and GSK-3β protein expressions were measured by western blot. The ratio of Bcl-2/Bax at mRNA level was detected by reverse transcription-polymerase chain reaction (RT-PCR). Results DEX significantly reduced plasma CK-MB, MDA concentration, and LDH level and increased SOD activity caused by I/R. The phosphorylation of Akt and GSK-3β was increased, Bcl-2 mRNA and the Bcl-2/Bax ratio was increased, and Bax mRNA was decreased in the DEX group as compared to the I/R group, while posttreatment with Wort attenuated the effects induced by DEX. Conclusion The results of this study suggest that DEX postconditioning may increase the phosphorylation of GSK-3β by activating the PI3K/Akt signaling pathway and may inhibit apoptosis and oxidative stress of the myocardium, thus exerting protective effects in diabetic rat hearts suffering from I/R injury.

Octreotide protects doxorubicin-induced cardiac toxicity via regulating oxidative stress.

To explore the role of octreotide in doxorubicin-induced (DOX) cardiac toxicity in rats, and to investigate its underlying mechanism. A total of 24 male Sprague Dawley (SD) rats were randomly assigned into 3 groups, including: the control group (NS group), the DOX-induced cardiac toxicity group (DOX group) and the OCT pretreatment + DOX-induced cardiac toxicity group (OCT group). Each group had 8 experimental SD rats. Electrocardiogram was performed in each rat before and after animal procedure, respectively. The serum and heart samples of each rat were collected 10 days after the surgical procedure. Cardiomyocyte apoptosis in the myocardial ischemic area of rats was determined by hematoxylin and eosin (HE) staining and Terminal Deoxynucleotidyl Transferase dUTP Nick-end Labeling (TUNEL) staining. DOX-induced oxidative stress was evaluated by detecting the activities of SOD (superoxide dismutase), MDA (malondialdehyde), GSH (glutathione), T-AOC (total antioxidant capacity) and CAT (catalase). The expression levels of nuclear factor E2 related factor-2 (Nrf2), heme oxygenase-1 (HO-1) and quinone oxidoreductase 1 (NQO1) were detected by Western blot and immunohistochemistry. Compared with the NS group, heart rate and voltage of QRS wave were both significantly reduced in the DOX group, whereas Q-T interval was significantly prolonged (p < 0.05). Arrhythmia was even found in some rats of the DOX group. However, rats in the OCT group had significantly higher heart rate and voltage of QRS wave, as well as shorter Q-T interval when compared with those of the DOX group (p < 0.05). The levels of plasma CK-MB and LDH were remarkably lower in the OCT group than those of the DOX group. The activities of SOD, GSH, CAT and T-AOC in cardiac homogenate of the OCT group were higher than those of the DOX group. However, MDA activity and ROS level in cardiac homogenate were remarkably reduced in the OCT group when compared with those of the DOX group (p < 0.05). Cardiac pathological lesions were alleviated by OCT pretreatment. Moreover, the expression levels of Nrf2, HO-1 and NQO1 were significantly upregulated in the OCT group than those of the DOX group. Octreotide improves the anti-oxidant capacity of cardiomyocytes via activating the Nrf2 pathway, thereby protecting doxorubicin-induced cardiac toxicity in rats.