Recent studies have demonstrated that perivascular adipose tissue (PVAT) releases vascular relaxation factor(s). In this study, we examined if PVAT releases other vasoactive factors in response to ...perivascular nerve activation by electrical field stimulation (EFS).
In Wistar-Kyoto rats, rings of superior mesenteric artery (MA) with intact PVAT (PVAT (+)) showed a greater contractile response to EFS than rings with PVAT removed (PVAT (-)). Superoxide dismutase (SOD) reduced the contractile response to EFS more in PVAT (+) MA than in PVAT (-) MA. Inhibitors of NAD(P)H oxidase and cyclooxygenase exerted a greater inhibition on EFS-induced contraction in PVAT (+) MA than in PVAT (-) MA. Inhibitors of tyrosine kinase (tyrphostin A25) and MAPK/ERK (U 0126) attenuated EFS-induced contraction in PVAT (+) MA in a concentration-related manner, while inactive forms of these inhibitors (tyrphostin A1 and U 0124) did not inhibit the response. Exogenous superoxide augmented the contractile response to EFS and to phenylephrine in PVAT (-) MA, and this augmentation was blunted by inhibition of tyrosine kinase and MAPK/ERK. EFS increased superoxide generation in isolated PVAT and PVAT (+)/(-) MA, which was attenuated by NAD(P)H oxidase inhibition. RT-PCR showed the mRNA expression of p(67phox) subunit of NAD(P)H oxidase and immunohistochemical staining confirmed its localization in the adipocytes of PVAT.
These results show that PVAT enhances the arterial contractile response to perivascular nerve stimulation through the production of superoxide mediated by NAD(P)H oxidase, and that this enhancement involves activation of tyrosine kinase and MAPK/ERK pathway.
Microarray profiling of 15 adjacent normal/tumor-matched esophageal squamous cell carcinoma (ESCC) specimens identified 40 up-regulated and 95 down-regulated genes. Verification of the microarray ...measurement by quantitative real-time reverse transcription PCR in the same set of samples as well as an additional 15 normal/tumor-matched samples revealed >95% consistency. These signatures can also be used to classify a recently reported ESCC microarray dataset. Moreover, these molecular signatures were used as templates to elucidate their corresponding protein-protein interaction (PPI) networks using the PPI databases, POINT and POINeT. As a result, 18 genes, of which six were not disclosed in the initial expression profile analysis, were found to be able to serve as the minimal discriminators for distinguishing ESCC tumors from normal specimens. Of these discriminators, ten (BGN, COL1A1, COL1A2, MMP9, CD44, FN1, TGFBI, PXN, SPARC and VWF) were associated with tumor metastasis and formed a highly interactive network with the first four molecules as 'hubs'. Our study not only reveals how novel insights can be obtained from gene expression profiling, but also highlights a group of highly interacting genes associated with metastasis in ESCC.
Although there are many classes of drugs, including cardiac glycosides, sympathomimetic inotropes, β-adrenergic antagonists, angiotensin-converting enzyme inhibitors (ACE inhibitors) and ...spironolactone
etc. used for the treatment of heart failure, the morbidity and mortality rates of patients after these treatments are not ameliorated. Chronic administration of Sympathomimetic inotropes also increased the arrhythmogenic effects. Consequently, improvement of treatment for heart failure remains a major medical challenge for the coming years. In this present experiment, the novel Na
+–K
+ ATPase inhibitor AT-11 was characterized for its inotropic and toxic properties. Comparing AT-11 with ouabain, we found that AT-11 concentration-dependently increased contractility in guinea pig heart preparations, and the safety index of AT-11 was better than ouabain
in vitro. In the
in vivo study, AT-11 was also safer than ouabain at the equieffective dose. Moreover, AT-11 slowed heart rate more than ouabain did. This may be due to a larger AT-11-induced increase in vagal reflex than with ouabain and an indirect decrease in sympathetic tone to prevent Ca
2+ overload.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
In Langendorff-perfused adult rat heart with constant pressure at 80 mmHg, we found doxazosin, an α
1
adrenoceptor blocker, at 10 μM prolonged PR interval and induced occasional arrhythmia followed ...by complete inhibition of the sinus rhythm, whereas bunazosin, another α
1
-blocker, at same concentration did not. The results of voltage-clamp study showed that, at the concentration of 10 μM, doxazosin inhibited
I
Na
,
I
(Ca,L)
,
I
to
, and
I
ss without changing
I
k1
but bunazosin only inhibited
I
(Ca,L)
about 30%. Doxazosin also caused markedly negative shift of the
I
Na
inactivation curve. In current-clamp study, doxazosin prolonged action potential duration in association with the decreased action potential amplitude and upstroke velocity, whereas bunazosin did not. We hypothesize that doxazosin-induced arrhythmia may result from the heterogeneous or different level of
I
(Ca,L)
blockade of AV nodal tissue. In conclusion, the present study suggests that bunazosin is safer than doxazosin for long-term treatment in view of electrophysiological effect. However, the underlying mechanism of doxazosin induced nodal arrhythmia is still needed to be determined.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Quinazoline-based compounds such as prazosin and its congeners including doxazosin, bunazosin, and terazosin are widely used as antihypertensive agents. However, there were many clinical observations ...showing that using these agents may result in higher risk of cardiovascular accidents in recent years. In this study, we compared the effects of four α-adrenoceptor antagonists: prazosin, doxazosin, bunazosin, and terazosin on occlusion–reperfusion injury. Langendorff-perfused rat hearts were pretreated with these four antagonists, and then the left main coronary artery was occluded. After 30 min occlusion, the hearts were reperfused for 2 h and the infarct sizes were measured. Two of the compounds studied, prazosin and doxazosin, apparently increased infarct size, CK-MB, and LDH activities after 2 h reperfusion. In contrast, bunazosin decreased infarct size and those biochemical indicators of cellular damage compared to control hearts. Although infarct size after reperfusion was differently changed by these four α-adrenoceptor antagonists, TUNEL-positive nuclei and caspase-3 protein expressions of all the groups were not significantly different. We supposed that the different effects of these four agents on infarct size came from the difference in necrosis rather than apoptosis.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
BackgroundMyocardial scarring after infarction (MI) can create areas of slowed conduction, which can lead to re-excitation of the heart, or re-entry. Reentrant arrhythmia is one of the ...electrophysiological mechanisms responsible for ventricular tachycardia after acute myocardial infarction (AMI). Since the sodium channel (Nav1.5) is a major contributor to cardiac electrical conduction, the objective of this study was to evaluate the effect of cell substrate stiffness on the kinetics of the Nav1.5.MethodsMI was created by permanent ligation of the left anterior descending artery in rats. After 7 days, hearts were decellularized and grossed into 1 mm rings for measuring stiffness by using an atomic force microscope. The hearts had an elastic modulus of 263.33±76.8 kPa at scar, and 27.26±3.97 kPa at a remote area (n=3). The surface of polydimethylsiloxane (PDMS) gels was tuned to match the stiffness of decellularized infarcted rat hearts (17.04±2.02 kPa, 110.56±8.70 kPa and 328.4±45.72 kPa, respectively, n=3). Human embryonic kidney 293 (HEK-293) cells were induced to stably express human Nav1.5. HEK-293 and human pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) were separately cultured on the PDMS substrate that mimicked stiffness of infarcted rat hearts for 24 h. Sodium channel currents (INa) and action potentials (APs) were recorded by patch clamp techniques.ResultsAs substrate stiffness increased, HEK-293 voltage dependent activation of Nav1.5 (INa) shifted significantly towards more positive voltage (Vhalf-28.42±5.12 mV, -33.47±6.98 mV, -19.84±5.24 mV, respectively, p<0.01 in one-way ANOVA, n=12), and the transition from closed-state into inactivation was faster (tau48.47±4.60ms, 40.67±8.07ms, 81.20±9.54ms, p<0.05, n=12). However, the current density, the steady-state inactivation curve and the recovery time were comparable between different PDMS. In iPSC-CMs, the slope of AP upstroke was decreased when stiffness was increased (30.00±1.38V/s, 23.91±0.65V/s, 20.93±0.34V/s, p<0.05, n=15).ConclusionIncreased substrate stiffness, similar to myocardial scar, alters the kinetics of Nav1.5 and affects the depolarization of cardiomyocytes, which likely contributes to slow conduction after MI.
OBJECTIVETetanus antitoxin (TAT) is an effective antitetanus medicine, but may sometimes cause adverse drug reactions such as rapid-onset anaphylactic shock and late-onset cutaneous adverse drug ...reactions, including exanthematous drug eruptions (EDE). Human leukocyte antigen (HLA) class I alleles are strongly associated with different types of cutaneous adverse drug reactions. This study aimed to assess whether there is an association between TAT-induced EDE and HLA-A, HLA-B, and HLA-C alleles in the Chinese Han population.
PATIENTS AND METHODSWe carried out an association study in 15 patients with TAT-induced EDE and two groups of general Han Chinese patients. Allele-level genotypes of the HLA-A, HLA-B, and HLA-C genes of each patient were determined using the PCR-sequence-specific oligonucleotides method.
RESULTSThe carrier frequency of HLA serotype A2 was significantly higher in the TAT-induced EDE patients than in the general Han Chinese subjects from the human major histocompatibility complex database n=283, odds ratio (OR)=6.93; P=0.0061. Particularly, the carrier frequency of three A2 alleles, including HLA-A*02:01, HLA-A*02:06, and HLA-A*02:07, is significantly higher than that of the control group (OR=14.40; P=2.4×10). Furthermore, HLA-B*39:01 was in complete linkage disequilibrium with HLA-A*02:06 in the case patients. Consequently, the distribution of the HLA-A*02:06/-B*39:01 haplotype was also significantly different in the cases and the controls (OR=105.00; P=0.0024).
CONCLUSIONThe HLA-A*02:06/-B*39:01 haplotype is a potential genetic marker for the TAT-induced EDE. Furthermore, the HLA-A2 serotype, especially three alleles A*02:01, A*02:06, and A*02:07, was identified to be associated with the TAT-induced EDE in the Han Chinese population for the first time.
Ventricular arrhythmogenesis is a key cause of sudden cardiac death following myocardial infarction (MI). Accumulating data show that ischemia, sympathetic activation, and inflammation contribute to ...arrhythmogenesis. However, the role and mechanisms of abnormal mechanical stress in ventricular arrhythmia following MI remain undefined. We aimed to examine the impact of increased mechanical stress and identify the role of the key sensor Piezo1 in ventricular arrhythmogenesis in MI. Concomitant with increased ventricular pressure, Piezo1, as a newly recognized mechano-sensitive cation channel, was the most up-regulated mechanosensor in the myocardium of patients with advanced heart failure. Piezo1 was mainly located at the intercalated discs and T-tubules of cardiomyocytes, which are responsible for intracellular calcium homeostasis and intercellular communication. Cardiomyocyte-conditional Piezo1 knockout mice (Piezo1
) exhibited preserved cardiac function after MI. Piezo1
mice also displayed a dramatically decreased mortality in response to the programmed electrical stimulation after MI with a markedly reduced incidence of ventricular tachycardia. In contrast, activation of Piezo1 in mouse myocardium increased the electrical instability as indicated by prolonged QT interval and sagging ST segment. Mechanistically, Piezo1 impaired intracellular calcium cycling dynamics by mediating the intracellular Ca
overload and increasing the activation of Ca
-modulated signaling, CaMKII, and calpain, which led to the enhancement of phosphorylation of RyR2 and further increment of Ca
leaking, finally provoking cardiac arrhythmias. Furthermore, in human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs), Piezo1 activation remarkably triggered cellular arrhythmogenic remodeling by significantly shortening the duration of the action potential, inducing early afterdepolarization, and enhancing triggered activity.This study uncovered a proarrhythmic role of Piezo1 during cardiac remodeling, which is achieved by regulating Ca
handling, implying a promising therapeutic target in sudden cardiac death and heart failure.
Abstract only
Background:
Patients with systemic lupus erythematosus (SLE) are twice more likely to develop cardiovascular disease than the general population, even though their plasma LDL ...cholesterol (LDL-C) levels are usually not elevated. To delineate the mechanisms, we examined the chemical properties of their LDL.
Methods and Results:
LDL isolated from SLE patients (LDL-C, 105±33 mg/dL; n=24) exhibited greater mobility in agarose gel electrophoresis than LDL of healthy control subjects (LDL-C, 121±25 mg/dL; n=24), secondary to an increased distribution of L5 (2.30±1.3% vs. 0.7±0.3%;
P
<0.0001), the most electronegative subfraction of LDL identified by anion-exchange chromatography, in total LDL. CX3CL1 is a membrane-bound chemokine expressed in injured endothelial cells (ECs). CD16
+
monocytes are CX3CR1-expressing cells that recognize CX3CL1. Compared with control, SLE patients had a twofold (
P
<0.001) increase in CX3CL1 and a threefold (
P
<0.0001) increase in CD16
+
monocytes in the plasma. Moreover, there was a positive correlation between the CX3CL1 and L5 levels (R=0.45;
P
<0.018). MALDI/TOF mass spectrometry of the lipid extracted from SLE-LDL revealed a shift from phosphatidylcholines (PCs) to lyso-PCs (LPCs), including m/
z
496.33, 524.36, 537.01, 550.94, when compared with the lipid of control LDL (Figure). The shift was especially prominent in L5. Exposing human aortic ECs to L5 but not normal LDL resulted in a fivefold (
P
<0.0001) increase in CX3CL1 expression with concomitant apoptosis. These effects of L5 were significantly attenuated by blocking the platelet-activating receptor, confirming the role of phospholipids in L5’s bioactivity.
Conclusions:
The increased distribution of LPC-rich electronegative LDL, which induces CX3CL1-CX3CR1 interactions between vascular cells, may contribute to the increased cardiovascular disease prevalence in SLE in the absence of LDL-C elevation.
AIM： To assess acellular ostrich corneal matrix used as a scaffold to reconstruct a damaged cornea. METHODS： A hypertonic saline solution combined with a digestion method was used to decellularize ...the ostrich cornea. The microstructure of the acellular corneal matrix was observed by transmission electron microscopy （TEM） and hematoxylin and eosin （H＆E） staining. The mechanical properties were detected by a rheometer and a tension machine. The acellular corneal matrix was also transplanted into a rabbit cornea and cytokeratin 3 was used to check the immune phenotype, RESULTS： The microstructure and mechanical properties of the ostrich cornea were well preserved after the decellularization process, in vitro, the methyl thiazolyl tetrazoUum results revealed that extracts of the acellular ostrich corneas （AOCs） had no inhibitory effects on the proliferation of the corneal epithelial or endothelial cells or on the keratocytes, The rabbit lamellar keratoplasty showed that the transplanted AOCs were transparent and completely incorporated into the host cornea while corneal turbidity and graft dissolution occurred in the acellular porcine cornea （APC） transplantation, The phenotype of the reconstructed cornea was similar to a normal rabbit cornea with a high expression of cytokeratin 3 in the superficial epithelial cell layer, CONCLUSION： We first used AOCs as scaffolds to reconstruct damaged corneas. Compared with porcine corneas, the anatomical structures of ostrich corneas are closer to those of human corneas. In accordance with the principle that structure determines function, a xenograft lamellar keratoplasty also confirmed that the AOC transplantation generated a superior outcome compared to that of the APC graft.
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