AIM To investigate the effects of iptakalim hydrochloride(Ipt) on potassium currents in cardiomyocytes derived from guinea pig and on the specific binding of glibenclamide (Gli) with sulfonylurea receptor(SUR_ 2A ) of ATP-sensitive potassium channel (K_ ATP ) in cardiac membranes derived from Wistar rats. The effects of Ipt on the association and dissociation kinetic processes of Gli binding with SUR_ 2A of K_ ATP in cardiac preparations were also determined. METHODS The effects of Ipt on potassium currents in cardiomyocytes were observed by using patch clamp technique(whole cell recording) after application of the drug in the bath. The experiments of the ass ociation and dissociation kinetic processes of K_ ATP blocker [ 3H]Gli binding with cardiac membranes were used. RESULTS (1)The potassium current-voltage curves (I-U curves) of cardiomyocytes derived from guinea pig were upward shifted by Ipt at the concentrations of 1 and 100 ?mol?L -1 . Within 5 minutes after application of the drug, the current amplitude increased to 124.9%?9.5%(n=5)and 151.6%?11.2%(n=7)of initial current amplitude respectively(P

Objective To investigate the correlation between asymmetric dimethylarginine (AD-MA) and endothelial dysfunction in patients with uremia.Methods Uremic patients who did not receive hemodialysis were defined as A group (n =40) ; uremic patients who had received hemodialysis were divided into B group (n =45) ;healthy people were defined as C group (n =20) ;and chronic kidney disease (stage 2 ～ 4) patients were defined as D group (n =20).The diameter of intima-media thickness,and endothelium-dependent or independent dilation (EDD or EID) of radial artery in right forearm were detected with diasonography.The levels of ADMA were determined by high-performance liquid chromatography.Results Compared to C group,the levels of ADMA in A,B and D groups were significantly increased [C:(0.78 ±0.19) μmol/L,A:(1.51 ±0.16) μ mol/L,B:(1.13 ±0.14) μmol/L,D:(0.92 ±0.11) μmol/L; P ＜0.05].Compared to A group,the levels of ADMA were significantly decreased in B group (P ＜0.05).EDD and EID were decreased significantly in A,B and D groups compared to C group [EDD:C:(13.52±1.73)％ vs A:(7.32 ±0.54)％,B:(9.02 ±0.86)％,D:(10.13 ±1.25)％,P ＜0.05;EID:C:(14.45±1.85)％ vsA:(10.37 ±1.51)％,B:(9.54±1.39)％,D:(11.17±1.56)％,P ＜0.05].EDD in B group was significantly lower than A group (P ＜0.05).In group A,a negative correlation was found between EDD and the level of ADMA (r =-0.81,P =0.020).Conclusions ADMA level was significantly increased in uremic patients.A close correlation existed between ADMA and endothelial dysfunction of radial artery.

OBJECTIVETo investigate the effects of non-neuronal muscarinic receptors (NNMR) stimulation on atherosclerosis and endothelial cells activation.

METHODSAtherosclerosis model was established in ApoE-/- mice by a high fat diet for 7 weeks. During the experimental periods, animals were received a low (7 mg/kg/d) or a high (21 mg/kg/d) dose of arecoline by gavage. At the termination of the treatments, serum total cholesterol and NO levels were measured, and the aorta morphology was analyzed by hematoxylin and eosin staining. The gene expression of monocyte chemoattractant protein-1 (MCP-1) and adhesion molecules in the thoracic aortas was determined by RT-PCR, and the MCP-1 protein expression and NF-κB activity were detected by Western blot analysis. NO production, MCP-1 secretion in cultured rat aortic endothelial cells (RAECs), and monocyte-endothelium adhesion assay were also performed after arecoline treatments.

RESULTSArecoline efficiently decreased atherosclerotic plaque areas, increased serum nitric oxide (NO) content, suppressed the mRNA and protein expression of MCP-1, and modulated the IκB-α degradation and P65 phosphorylation in the aortae of ApoE-/- mice. Furthermore, arecoline promoted NO production and suppressed MCP-1 secretion in cultured RAECs after ox-LDL exposure, and either atropine or NG-nitro-L-arginine methylester could abrogate these effects. Arecoline also significantly inhibited the adherence of U937 monocytes to the ox-LDL injured human umbilical vein endothelial cells, which could be abolished by atropine.

CONCLUSIONOur results indicate that arecoline attenuates the progression of atherosclerosis and inhibits endothelial cells activation and adherence by stimulating endothelial NNMR. These effects, at least in part, are due to its modulation on NF-κB activity.

Animals ; Aorta ; cytology ; Apolipoproteins E ; Arecoline ; pharmacology ; Atherosclerosis ; physiopathology ; prevention & control ; Cell Adhesion Molecules ; metabolism ; Chemokine CCL2 ; metabolism ; Cholesterol ; blood ; Disease Progression ; Endothelial Cells ; cytology ; drug effects ; Endothelium, Vascular ; Human Umbilical Vein Endothelial Cells ; cytology ; Humans ; I-kappa B Proteins ; metabolism ; Lipoproteins, LDL ; Mice ; Mice, Knockout ; Monocytes ; cytology ; NF-KappaB Inhibitor alpha ; Nitric Oxide ; blood ; Nitroarginine ; pharmacology ; Rats ; Receptors, Muscarinic ; physiology ; Transcription Factor RelA ; metabolism

OBJECTIVEOver the last few decades, diabetic cardiomyopathy has been identified as a significant contributor in cardiac morbidity. However, the mechanisms of diabetic cardiomyopathy have not been clarified.

METHODSIn the present study, a diabetic rat model was induced by the intraperitoneal injection of streptozotocin. The myocardial CD147 expression and extent of glycosylation, as well as thematrixmetalloproteinases(MMPs) expression and activity, were observed in the diabetic and synchronous rats.

RESULTSThe results showed that CD147 located on sarcolemma of cardiomyocytes. The myocardial CD147 expression and glycosylation were significantly increased in the diabetic rats as compared with the control. Expression of MMP-2 protein, MMP-2 and MMP-9 activity were also increased in left ventricular myocardium in the diabetic rats. Tamoxifen only inhibited the enhanced expression of myocardial CD147 in the diabetic rats, but not in synchronous control rats. Tamoxifen inhibited glycosylation of myocardial CD147 in both diabetic and control rats. The inhibition of tamoxifen on CD147 glycosylation was stronger than on the expression in the myocardium. The extent of myocardial CD147glycosylation was positively related toMMP-2 and MMP-9 activity. Tamoxifen induced an inhibition of myocardial MMP-2 and MMP-9 activity in the control and diabetic rats.

CONCLUSIONThese results indicate that myocardial CD147 expression, especially the extent of glycosylation, regulates MMP-2 and MMP-9 activity, then accelerates cardiac pathological remodeling inducing diabetic cardiomyopathy. Tamoxifen inhibits myocardial CD147 glycosylation and further depress the activity of MMPs. Therefore, tamoxifen may protect the diabetic rats against diabetic myocardium.

Animals ; Basigin ; metabolism ; Diabetes Mellitus, Experimental ; complications ; Diabetic Cardiomyopathies ; drug therapy ; Glycosylation ; Heart ; drug effects ; Matrix Metalloproteinase 2 ; metabolism ; Matrix Metalloproteinase 9 ; metabolism ; Myocardium ; metabolism ; Myocytes, Cardiac ; cytology ; Rats ; Sarcolemma ; metabolism ; Tamoxifen ; pharmacology

OBJECTIVEHigh altitue pulmonary edema (HAPE) impacts seriously people's health at high altitude. Screening of susceptibility genes for HAPE will be used for the evaluation and protection of susceptible people.

METHODSWe performed a genome-wide association study (GWAS) using Affymetrix SNP array 6.0 in 23 HAPE patients and 17 healthy controls. GO and Pathway analysis softwares were used to analyze and draw gene network.

RESULTSThirty-nine SNPs were found to be significantly different between case and control groups (P < 10(-4)). GO and Pathway analysis of 27 genes around the 39 SNPs indicated that these genes mainly participate in the regulating of cell proliferation, regulation of nitrogen compound metabolic process and G-protein coupled receptor protein signaling pathway and so on.

CONCLUSIONIt suggests that these SNPs and genes found in this study may be associated with the susceptibility of HAPE.

Adult ; Altitude Sickness ; genetics ; Asian Continental Ancestry Group ; genetics ; Case-Control Studies ; Genetic Predisposition to Disease ; Genome-Wide Association Study ; Humans ; Hypertension, Pulmonary ; genetics ; Polymorphism, Single Nucleotide ; Young Adult

The primary object of this fundamental research was to survey the synergistic cardiovascular effects of iptakalim, a novel ATP-sensitive potassium channel (K(ATP)) opener, and clinical first-line antihypertensive drugs, such as calcium antagonists, thiazide diuretics and β receptor blockers by a 2 x 2 factorial-design experiment. It would provide a theoretical basis for the development of new combined antihypertensive therapy program after iptakalim is applied to the clinic. Amlodipine besylate, hydrochlorothiazide and propranolol were chosen as clinical first-line antihypertensive drugs. Blood pressure, heart rate (HR) and cardiac functions were observed in anesthetized normal rats by an eight-channel physiological recorder. The results showed that iptakalim monotherapy in a low dose could produce significant antihypertensive effect. There was no interaction between iptakalim and amlodipine on the maximal changes of systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial blood pressure (MABP), the left ventricular systolic pressure (LVSP), and the left ventricular end-diastolic pressure (LVEDP) (P > 0.05). However, the effects of combination iptakalim/amlodipine on the maximal changes of SBP, DBP, MABP, LVSP and LVEDP were more obvious than those of iptakalim or amlodipine monotherapy. And there was strong positive interaction between iptakalim and amlodipine on the maximal changes of HR (P>0.05). According to the maximal changes of DBP, MABP, LVSP and LVEDP (P < 0.05) of combination iptakalim with hydrochlorothiazide, there was strong positive interaction between them. But there was no interaction between iptakalim and hydrochlorothiazide on the maximal drop of SBP and HR (P > 0.05). According to the maximal drops of DBP, MABP of combination iptakalim with propranolol, there was strong positive interaction between them (P < 0.05). But there was no interaction between iptakalim and propranolol on the maximal changes of SBP, LVSP, LVEDP and HR (P > 0.05). In conclusion, it was the first time to study the effects of amlodipine, hydrochlorothiazide or propranolol, which had different mechanisms of action from iptakalim, on cardiovascular effects of iptakalim in anesthetized normal rats. This study proved that the combination of iptakalim with hydrochlorothiazide or propranolol respectively had significant synergism on lowering blood pressure, while the combination of iptakalim/amlodipine had additive action on lowering blood pressure. Meanwhile the antihypertensive effect was explicit, stable and long-lasting. Iptakalim thus appears suitable for the clinical treatment of hypertensive people who need two or more kinds of antihypertensive agents.
Amlodipine ; pharmacology ; Animals ; Antihypertensive Agents ; pharmacology ; Blood Pressure ; drug effects ; Drug Synergism ; Heart Rate ; Hydrochlorothiazide ; pharmacology ; Hypertension ; Propranolol ; pharmacology ; Propylamines ; pharmacology ; Rats

Objective To explore the protection of valsartan combined with simvastatin on kidney in early diabetic nephropathy rats. Methods Diabetic nephropathy rats model were induced by streptozocin (STZ) ,the experimental rats were randomly divided into 5 groups: control (group C), diabetic nephropathy (group D) ,diabetes treated with valsartan (group X) ,diabetes treated with simvastatin (group Z) ,and diabetes treated with combined valsartan and simvastatin ( group L). Blood glucose (BG), HbA1c, blood cholesterol ( TC), trigalloylglycerol ( TG ), blood ureanitrogen ( BUN ), serum creatinine (SCr) , urinary albumin excretion rate (UAER) were measured, and the podocyte ultrastructure was observed by transmission electronic microscopy. Results The levels of BG, HbA1c,TC,TG and UAER in group D increased significantly compared togroup C(BG:[20.3 ±3.2]mmol/L vs [6.1 -±0. 4]mmol/L;HbA1c:[7.18 ±0.47]% vs [3.37 ±0. 15]% ;TC: [2. 69 ±0. 35] mmol/L vs [1.28 ±0. 24] mmol/L;TG: [3.09 ±0. 37] mmol/L vs [1.18 ±0. 25]mmol/L) (P ＜ 0. 05 ). Creatinine clearance rates (Ccr) in group D ( [0. 89 ± 0. 19] ml/min ) decreased significantly compared to group C( [1.27 ±0. 33] ml/min) ,as well as group X,Z and L( Ps ＜ 0. 05 ). UAER in group D was significantly higher than that in group C ( [19. 87 ±3. 85] μg/24 h vs [3. 67 ± 1.01] μg/24 h) (P ＜ 0. 05 ), as well as group X, Z and L ( P ＜ 0. 05 ), and the improvement in group L was particularly significant ( P ＜ 0. 05 ). The projections of podocyte in group D severely syncretized, there were slightly improvement in group X, Z and L compared to group D, and the improvement in group L was remarkable. Conclusion The treatment with valsartan, simvastatin and their combination will effectively protect the kidney in early diabetic nephropathy rats,and the effect of using the combination therapy is much better.

OBJECTIVETo construct T vectors based on Xcm I recognition site and optimize the PCR fragments for its ligation.

METHODSWe firstly cloned the human histone H4 cDNA containing one Xcm I recognition site at both its 5' and 3' end into pCDNA 3.0 vector and then generated T vector with pCDNA 3.0 backbone by cutting the recombinant plasmid with Xcm I. To increase the ligation efficiency, the primers were firstly phosphorylated before DNA fragments amplification and then the PCR products were treated with Taq DNA polymerase and dATP after PCR amplification. Two DNA fragments with the length of 312 bp and 1 329 bp were ligated to it and the ligation mixture was transformed into E. coli DH5α competent cells and the positive rates of the transformants were evaluated by PCR and DNA agarose gel electrophoresis.

RESULTSOur results showed that the T vector produced by our method could ligate to the target DNA fragments with high efficiency. Besides, the phosphorylation state of the primers used for PCR amplification is also an important factor determining the cloning efficiency. What's more, as for longer DNA fragments, retreatment with Taq DNA polymerase and dATP after PCR amplification and purification could improve the ligation efficiency significantly.

CONCLUSIONOur protocol may overcome the dependence on blue/white screening to get positive clones and provide a potent way to generate T vectors and ligate them to the target PCR fragment.

Cloning, Molecular ; DNA, Complementary ; genetics ; Escherichia coli ; genetics ; Genetic Vectors ; Histones ; genetics ; Humans ; Polymerase Chain Reaction ; methods

OBJECTIVEHigh altitude pulmonary edema (HAPE), a life-threatening disease, has no biological markers used for the routine prevention, diagnosis and treatment. The aim of this study was to identify serum proteins differentially expressed in patients with HAPE for discovering essential biomarkers.

METHODSA complete serum proteomic analysis was performed on 10 HAPE patients and on 10 high altitude and 11 sea level healthy people as control using two-dimensional gel electrophoresis, followed by matrix-assisted laser desorption/ionization mass spectrometry and peptide mass fingerprinting. Finally, two most significantly changed proteins were validated by enzyme-linked immunosorbent assay (ELISA).

RESULTSEight protein spots stained with differential intensity, respresenting 5 distinct proteins were identified in patients compared with healthy controls through analysis of these composite gels. Among them, four proteins, namely alpha 1-antitrypsin(alpha1-AT), Haptoglobin(Hp), apolipoprotein A-1 (apoA-1) and Complement C3 increased remarkably, while one protein, apolipoprotein A-IV (apoA-IV) decreased significantly. The variation of alpha1-AT and Haptoglobin, as detected by ELISA, was consistent with the results from proteomic analysis.

CONCLUSIONSIt is well known that Hp, alpha1-AT and complement C3 are associated with inflammation and apoA-1 and apoA-IV play important roles in lipid absorption, transport and metabolism. Therefore, the significant expression changes of Hp, alpha1-AT and complement C3 and apoA-1 and apoA-IV between HAPE patients and their corresponding healthy controls highlight the role of inflammatory response system and lipid metabolism system in the pathophysiology of HAPE.

Altitude ; Biomarkers ; blood ; Blood Proteins ; metabolism ; Case-Control Studies ; Electrophoresis, Gel, Two-Dimensional ; Enzyme-Linked Immunosorbent Assay ; Humans ; Peptide Mapping ; Proteome ; Pulmonary Edema ; blood ; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization

OBJECTIVETo study the effects of iptakalim (Ipt), an ATP-sensitive potassium channel opener, on cardiac remodeling induced by isoproterenol (ISO) in Wistar rats.

METHODSISO was given subcutaneously (85 mg/(kg x d), sc, 7 days) to induce cardiac remodeling in rats. The rats in Ipt treated group were administrated with Ipt 3 mg/kg (po) after ISO injection. After treated with Ipt for 6 weeks, the hemodynamic parameters were tested by an eight channel physiological recorder (RM-6000). Then the heart weight was weighed and the cardiac remodeling index was calculated. HE stain and Masson's stain were employed to perform histological analysis, the hydroxyproline(Hyp) content in cardiac tissue was detected by colorimetric method, radioimmunoassay was used to measure the plasma levels of endothelin-1 (ET-1) and prostacyclin (PGI2).

RESULTSSix weeks after ISO injection, the cardiac functions of model group were damaged markedly compared with those of normal group. The characteristics of ventricular remodeling in model group included that the heart weight index, myocyte cross-sectional area, myocardial fibrosis, and the hydroxyproline content in cardiac tissue were all increased significantly. The plasma level of ET-1 was increased, while the plasma level of PGI2 was decreased significantly. These changes could be reversed by Ipt treatment (3 mg/(kg x d) for 6 weeks).

CONCLUSIONIpt can reverse cardiac remodeling induced by isoproterenol in rats. The endothelial protective effect regulating effects of Ipt on the balance between the ET-1 and PGI2 system may be involved in its mechanisms.

Animals ; Endothelin-1 ; blood ; Hemodynamics ; Hydroxyproline ; metabolism ; Isoproterenol ; pharmacology ; KATP Channels ; drug effects ; Male ; Myocardium ; metabolism ; Propylamines ; pharmacology ; Prostaglandins I ; blood ; Rats ; Rats, Wistar ; Ventricular Remodeling ; drug effects