Peripheral leukocyte count and risk of bleeding in patients with non-valvular atrial fibrillation taking dabigatran: a real-world study / 中华医学杂志(英文版)

BACKGROUND@#The association between peripheral leukocyte count and bleeding events in nonvalvular atrial fibrillation (NVAF) patients treated with dabigatran remains unclear. This study aimed to explore the association between leukocyte count and bleeding events after excluding other confounders in NVAF patients taking dabigatran.@*METHODS@#A total of 851 NVAF patients treated with dabigatran (110 mg bid) were recruited from 12 centers in China from February 2015 to December 2017. Follow-up was completed by May 2018. The exposure and outcome variables were leukocyte count measured at baseline and the number of bleeding events within the subsequent 6 months. Multivariate Cox proportional hazards models were constructed to analyze independent associations, and a Cox proportional hazards regression with cubic spline functions and smooth curve fitting (penalized spline method) was used to address nonlinearity between leukocyte count and bleeding. The inflection point was calculated using a recursive algorithm, and then a two-piecewise Cox proportional hazards model for both sides of the inflection point was constructed.@*RESULTS@#During 6-month follow-up, 87 participants occurred bleeding events. For every 1 × 10/L increase in leukocyte count, the risk of bleeding increased by 11% (hazard ratio [HR]: 1.11, 95% confidence interval [CI]: 0.99-1.25). The smooth curve showed nonlinear relationship between leukocyte count and bleeding events. The inflection point of the leukocyte count was 6.75 × 10/L. For leukocyte counts < 6.75 × 10/L, the HR (95% CI) was 0.88 (0.69-1.13), and for leukocyte counts ≥ 6.75 × 10/L, the HR (95% CI) was 1.28 (1.09-1.51).@*CONCLUSION@#This study found a J-shaped association between baseline leukocyte count and risk of bleeding in NVAF patients treated with dabigatran.@*CLINICAL TRIAL REGISTRATION@#NCT02414035, https://clinicaltrials.gov.

Peripheral leukocyte count and risk of bleeding in patients with non-valvular atrial fibrillation taking dabigatran: a real-world study / 中华医学杂志(英文版)

Background@#The association between peripheral leukocyte count and bleeding events in nonvalvular atrial fibrillation (NVAF) patients treated with dabigatran remains unclear. This study aimed to explore the association between leukocyte count and bleeding events after excluding other confounders in NVAF patients taking dabigatran.@*Methods@#A total of 851 NVAF patients treated with dabigatran (110 mg bid) were recruited from 12 centers in China from February 2015 to December 2017. Follow-up was completed by May 2018. The exposure and outcome variables were leukocyte count measured at baseline and the number of bleeding events within the subsequent 6 months. Multivariate Cox proportional hazards models were constructed to analyze independent associations, and a Cox proportional hazards regression with cubic spline functions and smooth curve fitting (penalized spline method) was used to address nonlinearity between leukocyte count and bleeding. The inflection point was calculated using a recursive algorithm, and then a two-piecewise Cox proportional hazards model for both sides of the inflection point was constructed.@*Results@#During 6-month follow-up, 87 participants occurred bleeding events. For every 1 × 109/L increase in leukocyte count, the risk of bleeding increased by 11% (hazard ratio [HR]: 1.11, 95% confidence interval [CI]: 0.99–1.25). The smooth curve showed nonlinear relationship between leukocyte count and bleeding events. The inflection point of the leukocyte count was 6.75 × 109/L. For leukocyte counts < 6.75 × 109/L, the HR (95% CI) was 0.88 (0.69–1.13), and for leukocyte counts ≥ 6.75 × 109/L, the HR (95% CI) was 1.28 (1.09–1.51).@*Conclusion@#This study found a J-shaped association between baseline leukocyte count and risk of bleeding in NVAF patients treated with dabigatran.@*Clinical trial registration@#NCT02414035, https://clinicaltrials.gov.

SCN5A mutation in patients with Brugada electrocardiographic pattern induced by fever / 中华心血管病杂志

<p><b>OBJECTIVE</b>To explore the relationship between SCN5A, SCN1b, SCN3b and GPD1L genotypes and the risk of malignant arrhythmia in patients with Brugada electrocardiographic pattern induced by fever.</p><p><b>METHODS</b>The clinical data and peripheral blood of patients with Brugada electrocardiographic pattern induced by fever were collected. Patients with depolarization abnormality associated with hypertension, coronary heart disease, drugs and other factors were excluded. The direct DNA sequencing was used to screen the mutation of candidate gene SCN5A, SCN1b, SCN3b and GPD1L. If gene variation was found, mutation or polymorphism was then determined by comparison with 200 control individuals. The relationship between genotype and phenotype as well as the risk of malignant arrhythmia were analyzed.</p><p><b>RESULTS</b>Five eligible patients with fever-induced Brugada ECG pattern were included in this study. TypeI Brugada ECG was presented in all five patients in fibrile state and disappeared in normothermia. No sudden cardiac death (SCD) occurred and no ventricular arrhythmia was presented in Holter monitor during the 3 to 5 years follow-up period. Six gene variants were found including a novel missense mutation of base C to T, named Arg965 Cys (R965C), which located in 965 codon of the 17 exon in SCN5A, and five SCN5A polymorphisms including A29A (c.87A>G), R1193Q (c.3578G>A), D1819D (c.5457T>C), exon11 -24G>A, exon23 +4A>G.</p><p><b>CONCLUSION</b>SCN5A mutation is related to fever-induced Brugada ECG pattern. However, individuals with Brugada ECG pattern induced by fever bear low risk of malignant arrhythmia and SCD during fibrile state and follow up in this small patient cohort.</p>

Remote postconditioning induced by brief pulmonary ischemia and reperfusion attenuates myocardial reperfusion injury in rabbits / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>The lung is one of the most important organs that are sensitive to ischemia. We hypothesized that remote postconditioning (RPostC) induced by brief occlusion and reperfusion of the pulmonary artery could attenuate myocardial reperfusion injury.</p><p><b>METHODS</b>Thirty rabbits were randomized into three groups. Group ischemia-reperfusion (IR) (n = 10) were anesthetized rabbits subjected to 30-minute occlusion of the left anterior descending coronary artery followed by 180-minute reperfusion. Group RPostC (n = 10) had the left pulmonary artery blocked for five minutes followed by a 5-minute reperfusion, and the left anterior descending coronary artery (LAD) occluded for 30 minutes with a 180-minute reperfusion. Group L-N(w)-nitro-L-arginine methylester (L-NAME) + RPostC (n = 10) had the left pulmonary artery blocked for five minutes followed by a 5-minute reperfusion and intravenous infusion of L-NAME (10 mg/kg), and the LAD occluded for 30 minutes with a 180-minute reperfusion. Blood samples were taken for levels of creatine kinase (CK), superoxide dismutase (SOD) and malondialdehyde (MDA) at three different time points. At the end of the experiment, tissue samples of the infarcted region were harvested to calculate the cardiomyocyte apoptosis index (AI) by TUNEL. A piece of left and right lung tissue was harvested to evaluate the damage to the lung.</p><p><b>RESULTS</b>After reperfusion for 180 minutes, the concentration of CK was lower in group RPostC, (4.79 ± 0.27) U/ml, than that in group IR, (6.23 ± 0.55) U/ml (P < 0.01), and group L-NAME + RPsotC, (5.86 ± 0.42) U/ml (P < 0.01). The concentration of MDA was lower in group RPostC, (6.06 ± 0.36) nmol/ml, than that in group IR, (11.41 ± 0.91) nmol/ml (P < 0.01), and group L-NAME + RPostC, (11.06 ± 0.62) nmol/ml (P < 0.01). The activity of SOD was higher in group RPostC, (242.34 ± 25.02) U/ml, than that in group IR, (148.05 ± 18.24) U/ml (P < 0.01), and group L-NAME + RPostC, (160.66 ± 9.55) U/ml (P < 0.01). The apoptosis index was lower in group RPostC, (14.25 ± 5.20)%, than that in group IR, (35.77 ± 10.09)% (P < 0.01), and group L-NAME + RPostC, (30.37 ± 7.76)% (P < 0.01). No significant difference caused by pulmonary ischemia was found in the lung tissue among the three groups.</p><p><b>CONCLUSIONS</b>RPostC may attenuate myocardial ischemia-reperfusion injury connected to the activity of endothelial nitric oxide synthase. Brief pulmonary ischemia may not be harmful to lungs.</p>

NADPH oxidase activity does not affect cellular cholesterol loading in vascular smooth muscle cells / 生理学报

Reactive oxygen species generated by NADPH oxidase enhance aortic vascular smooth muscle cell proliferation and migration which play an important role in the pathophysiology of atherosclerosis. We investigated the role of NADPH oxidase in the cellular cholesterol metabolism in vascular smooth muscle cells using p47phox-deficient cells. Wild-type and p47phox knockout vascular smooth muscle cells were loaded with cholesterol for 72 h by using 10 mg/L cholesterol:methyl-beta-cyclodextrin complexes and then incubated with or without 0.3 mg/L thrombin for 10 min. Foam cell formation was determined by accumulation of intracellular cholesterol, oil Red O-stained lipid droplets. After cholesterol loading, cellular lipid droplets raised sharply, cellular cholesterol increased from (31.4+/-2.0) to (61.0+/-2.1) mg/g protein (P<0.05) in wild-type cells, and from (29.8+/-2.5) to (51.3+/-3.1) mg/g protein (P<0.05) in p47phox deficient cells, but the difference between the two cell types was not significant. Immunostaining showed decreased levels of smooth muscle alpha-actin and increased levels of macrophage marker Mac-2 in both wild-type and p47phox deficient vascular smooth muscle cells. One of the macrophage-related inflammation genes, monocyte chemoattractant protein-1 (MCP-1) expression did not change in both two cell types detected by immunostaining. Although additional incubating with thrombin, another macrophage-related inflammation gene, vascular cell adhesion molecule-1 (VCAM-1) expression was similar in all groups analyzed by real-time RT-PCR. However, the expression of ATP-binding cassette transporter A1 (ABCA1), acyl-coenzyme A:cholesterol acyltransferase 1 (ACAT1), the key proteins in cellular cholesterol metabolism, were similarly increased (P<0.05) in both two cell types as determined by quantitative real-time RT-PCR and Western blot, and it was not related to the state of oxidative stress. Interestingly, the expression of adipophilin, the lipid droplet related protein, had the similar results with ABCA1 and ACAT1, but, in wild-type cells, its expression also increased merely incubating with thrombin as determined by quantitative real-time RT-PCR. Together, these results suggest that p47phox-dependent NADPH oxidase is not involved in transdifferentitation of vascular smooth muscle cells into macrophage-like state after cholesterol loading. Deleting p47phox gene does not affect the cellular cholesterol metabolism in vascular smooth muscle cells.

Effect of puerarin on ADMA-DDAH system in human umbilical vein endothelial cells cultured with oxidized free radical / 中国中西医结合杂志

<p><b>OBJECTIVE</b>To observe the effects of puerarin on activity of dimethylarginine dimethylaminohydrolase (DDAH) in human umbilical vein endothelial cells (HUVECs) cultured with oxidized free radical (OFR), to explore the effect of puerarin on metabolic mechanism of asymmetric dimethylarginine (ADMA).</p><p><b>METHODS</b>HUVECs of the 3rd - 6th passage cultured with modified Jaffe's method were divided into 4 groups, the blank control group cultured with DMEM medium, the OFR group cultured with DMEM medium containing 0.1 mmol of OFR per liter, the puerarin group 1 and 2 cultured with DMEM medium containing 0.1 mmol of OFR per liter as well as 0.5 mg/ml and 1.0 mg/ml of puerarin respectively. After being incubated for 24 h, activity of nitric oxide synthase (NOS), contents of nitric oxide (NO), ADMA, endothelin (ET), and L-citrulline (L-cit) in the supernate were measured, and DDAH protein expression in the lysate was detected by Western blotting.</p><p><b>RESULTS</b>Compared with those in the blank control group, ADMA and ET contents were higher, while the levels of NO and L-cit and the activity of NOS were lower markedly, but the DDAH expression changed insignificantly in the OFR group. These abnormalities were restored significantly in the puerarin groups.</p><p><b>CONCLUSION</b>The increase of ADMA in OFR injured HUVECs was correlated with the reduction of DDAH activity and irrelevant to DDAH expression. Puerarin could promote ADMA metabolism through increasing DDAH activity, and improve NOS activity, thus to reduce the impairing of OFR on endothelial function.</p>

Promoting effect of hyperhomocysteinemia on vascular calcification in rats / 中国应用生理学杂志

<p><b>AIM</b>To explore the effect of hyperhomocysteinemia on vascular calcification and the underlying mechanism of it.</p><p><b>METHODS</b>Arterial calcification of Sprague-Dawley rats was induced by vitamin D3 plus nicotine. Hyperhomocysteinemia was established by feeding high methionine diet for six weeks and was assessed b y plasma total homocysteine (tHcy) level detected by HPLC method. Calcification was confirmed by von Kossa staining, measurement of calcium content, alkaline phosphatases (ALP) activity and osteocalcin (OC) concentration of vascular tissue. Lipid conjugated dienes formation were determined to reflecting the production of lipid peroxide.</p><p><b>RESULTS</b>The results showed that there were mass black granules deposited in aortic wall of the calcified rats by von Kossa staining. Calcium content, ALP activity, OC concentration in calcified rats increased by 8.09-fold, 45.57% and 2.81-fold compared with those of the control group (P < 0.01). Calcium content in calcified rats with high methionine diet increased by 34.29% compared with that of the calcified rats, while ALP activity and OC content decreased by 29.13% and 74.69% compared with that of the calcified rats. Lipid conjugated dienes formation in plasma of the rat with high methionine diet and of calcified rats with high methionine diet increased by 1.93 and 2.89-fold compared with those of the control group, respectively (P < 0.01), and in calcified rats with high methionine diet group was increased by 32.90% compared with that of high methionine diet group (P < 0.01).</p><p><b>CONCLUSION</b>Hyperhomocysteinemia could promote vascular calcification, which might be mediated through the production of lipid peroxide.</p>

Levels of adrenomedullin and proadrenomedullin N-terminal 20 peptide in myocardium and aorta of spontaneously hypertensive rats and Wistar-Kyoto rats / 生理学报

In this study, we observed the levels of adrenomedullin (ADM) and proadrenomedullin N-terminal 20 peptide (PAMP) in myocardium and aorta of spontaneously hypertensive rats (SHRs) in comparison with Wistar-kyoto (WKY) rats. Contents of ADM and PAMP were measured by radioimmunoassay (RIA) in plasma, myocardium and aorta. The amount of Pro-ADM mRNA of myocardium and aorta was determined by competitive quantitative reverse transcription polymerase chain reaction (RT-PCR). In SHRs the amounts of Pro-ADM mRNA of myocardium and aorta were 66.7% (P<0.01) and 73% (P<0.01) higher than those in WKY rat, respectively. In SHRs, the levels of ADM in plasma, myocardium and aorta were 29%, 76.7% and 79% (all P<0.01) higher than those in WKY rats, respectively. The level of PAMP in SHRs was increased by 42.5% in plasma (P<0.01), 47.2% in myocardium (P<0.0.1) and 27.3% in aorta (P<0.05) compared to WKY rats, respectively. In addition, the ratio of ADM content to PAMP content in SHRs group was increased compared with that in WKY group (2.0+/-0.25 vs 1.64+/-0.3 and 2.2+/-0.18 vs 1.56+/-0.28, in myocardium and aorta, respectively, P<0.01). These results suggest that ProADM gene expression is up-regulated and the increase in ADM and PAMP is different in SHRs. The significance of inconsistency of increase in ADM and PAMP in SHRs needs to be further investigated.