Changes of OX40 ligand expression in patients with acute coronary syndromes

AIM: To investigate the changes of OX40 ligand expression on monocytes and serum soluble OX40 ligand in patients with acute coronary syndromes (ACS).METHODS: The present study included healthy controls (n=30), patients with stable angina (SA, n=40) and patients with ACS, including unstable angina (UA, n=50) and acute myocardial infarction (AMI, n=30). The expression of OX40L on platelets was analyzed with flow cytometry and serum level of soluble OX40L (sOX40L) was determined with ELISA.RESULTS: The expression of OX40L on monocytes and serum level of sOX40L were significantly higher in patients with UA and AMI compared to healthy controls and patients with SA. In patients with AMI, sOX40L levels showed no significant increase when compared to patients with UA, while AMI patients had a peak level of sOX40L at 24 h after AMI. Percutaneous transluminal coronary angioplasty (PTCA) induced a marked rise in sOX40L levels in all patients. However, OX40L expression on monocytes showed no difference between patients with PTCA, before and after operation.CONCLUSION: The expression of OX40L may participate the mechanism of ACS and represent a marker for the activity of coronary disease.     

Inhibitory effect of high-dose Xuezhikang on inflammatory response induced by percutaneous coronary intervention in patients with unstable angina

AIM: To study the inhibitory effect of high-dose Xuezhikang,administered before percutaneous coronary intervention (PCI) on inflammatory response induced by PCI in patients with unstable angina (UA).METHODS: All patients with UA in class Ⅲ and ⅡB according to Braunwald classification were considered for inclusion in the present study.Finally,196 patients received Xuezhikang treatment 72 h before coronary angiography and successfully performed PCI with elevated C-reactive protein (CRP) level (>3 mg/L) were randomised to 2 groups: 1.2 g/d of Xuezhikang as group A,or 2.4 g/d of Xuezhikang as group B.The levels of CRP were measured at baseline,after 3 days of therapy (before procedure) and 48 hours after PCI.The patients were followed-up for 6 months for major adverse coronary events and left ventricular ejection fraction.RESULTS: There was no significant difference in the mean CRP level among the two randomized groups (P>0.05),however,after three days of pharmacological treatment,there was significantly reduced CRP content in group A ［(5.44±1.57） mg/L vs （4.04±1.54） mg/L,P<0.05］ and in group B ［(5.42±1.36） mg/L vs （3.60±1.14） mg/L,P<0.05］ compared with admission.Measurements performed 48 hours after the procedure revealed a marked CRP level increase in group A (up to 9.22 mg/L±5.03 mg/L) and an obvious increase in groups B (up to 4.97 mg/L±1.75 mg/L,P<0.05) compared with pre-procedure.The serum level of CRP in B group was distinctly lower than that in A group before (P<0.05) and after the procedure (P<0.05),respectively.Major adverse coronary events during the 6-month clinical follow-up occurred less in group A than that in group B ［21/104 (20.2%) vs 9/92 (9.8%); patients,P<0.05］.Follow-up echocardiography revealed lower left ventricular ejection fraction in group A than that in group B (55.41%±10.93% vs 59.30%±9.99%,P<0.05).CONCLUSION: High-dose Xuezhikang therapy,administered before PCI,has better inhibition effect than low-dose on inflammatory response induced by PCI in patients with UA.Attenuation of inflammatory response may be crucial for the reduction of coronary events following invasive coronary interventions.     

Complement activation in acute coronary syndromes

AIM: To evaluate complement activation in patients with all forms of acute coronary syndromes (ACS) and to examine the relationship between the degree of complement activation and myocardial injury.METHODS: The subjects were divided into 2 groups: 110 ACS patients (group ACS) and 18 healthy persons (group control).One hundred and ten patients with ACS were divided into 3 sub-group: 51 patients with ST-segment elevated myocardial infarction (STEMI),28 patients with non-ST-segment elevated myocardial infarction (NSTEMI) and 31 patients with unstable angina (UA).Complement 3 (C₃),complement 4 (C₄),troponin T (TnT) as well as creatine kinase MB (CK-MB) were evaluated.RESULTS: Plasma C₃ and C₄ peak levels were significantly higher in patients with STEMI ［(1 525±302)mg/L and (423±123) mg/L］ and NSTEMI ［(1 516±289)mg/L and (396±68) mg/L］ than those in patients with UA ［(1 275±172)mg/L and (356±91) mg/L］ and the control subjects ［(1 072±196)mg/L and (182±73) mg/L］ (P<0.01 for all).Also,C₃ and C₄ serum levels in patients with UA were significantly higher than those in control subjects (P<0.01 for all).At one-week follow-up,plasma levels of C₃ and C₄ were significantly different among various days in patients with ACS (P<0.01).Plasma C₃ and C₄ levels in ACS showed a relationship with peak creatine kinase MB (CK-MB) and troponin T (TnT) levels (P<0.01).CONCLUSION: Plasma C₃ and C₄ levels are elevated in ACS in present study.The relationship between C₃,C₄ levels and ACS suggests that the complement activation is related to necrosis within the myocardium.     

Effects of atorvastatin on nitric oxide,endothelin-1 and myocardial function in a rabbit model of acute myocardial infarction and reperfusion

AIM: To evaluate the effects of atorvastatin on nitric oxide(NO), endothelin-1(ET-1)and myocardial no-reflow in a rabbit model of acute myocardial infarction and reperfusion(AMI/R). METHODS: Twenty-four rabbits were randomized into 3 groups: 8 in AMI/R group, 8 in atorvastatin-treated group(5 mg·kg-1·d-1)and 8 in sham-operated group. Animals in the former two groups were subjected to 60 min of coronary occlusion followed by 120 min of reperfusion. Data on haemodynamics were collected. NO in blood sample, and in normal, and in infarcted reflow and no-reflow myocardium were evaluated respectively by nitrate reductase method. The levels of ET-1 in blood sample, and in normal, infarcted reflow and no-reflow myocardium were determined by radioimmunoassay. RESULTS: (1)Compared to the baselines, the heart rate(HR), systolic blood pressure(SBP), diastolic blood pressure(DBP), left ventricular systolic pressure(LVSP), maximal rate of increase and decline in left ventricular pressure(±dp/dtmax)and cardiac output(CO)in AMI/R and atorvastatin-treated groups were significantly declined, whereas left ventricular end-diastolic pressure(LVEDP)was increased after 60 min of coronary occlusion and 120 min of reperfusion(P<0.05 or P<0.01). However, in atorvastatin-treated group, LVSP, LVEDP, ±dp/dtmax and CO at the time point of 120 min of reperfusion recovered more significantly than those at the time point of 60 min of coronary occlusion(P<0.01), which was more significant than those in AMI/R group(P<0.05 or P<0.01). Compared to AMI/R group, the SBP and DBP were significantly heigher in atorvastatin-treated group(P<0.01).(2)In atorvastatin-treated group, the levels of ET-1 in blood sample were significantly lower than those in AMI/R group(P<0.01), and the levels of NO were significantly higher(P<0.01). Moreover, the levels of NO or ET-1 in infarcted reflow myocardium were significantly lower than that in AMI/R group(P<0.05 or P<0.01).(3)Atorvastatin could ameliorate myocardial function. CONCLUSION: Atorvastatin is effective in increasing NO and reducing ET-1 in blood plasma and local myocardium, and in protection of endothelial cells. Atorvastatin also has a beneficial effect on improving left ventricular function during acute myocardial infarction and reperfusion in rabbits.     

Effect of different PRA serum levels from patients with β-thalassemia on the proliferation and differentiation potential of the hematopoietic stem cells /progenitor cells of cord blood

AIM: To probe the effect of different panel reactive antibody(PRA) serum levels from patients with β-thalassemia on the proliferation and differentiation potential of the hematopoietic stem /progenitor cell of cord blood.METHODS: 1×105 mononuclear cells (MNCs) isolated from umbilical cord blood were incubated with different PRA serum levels (0 μL,50 μL,100 μL) respectively and complement,inoculated into the methylcellulose cultural system.The proliferation and differentiation potential of the hematopoietic stem /progenitor cell of cord blood by the colony formation assay were detected on day 7 and day 14,respectively.RESULTS: After culture of 7 days,the total colonies and CFU-GM were 88.20±9.41,79.00±11.39 in group A and 88.60±9.12,79.20±10.44 in group B,which were significantly higher than those of 20.60±7.39,15.20±4.66 in group C and those of 4.00±2.05,1.40±0.51 in group D (P<0.01).Meanwhile compared with group A and group E,no significant difference was found (P>0.05).After culture for 14 days,the total colonies and CFU-GM were 216.00±31.10,117.40±24.80 in group A and 213.20±31.06,116.00±19.75 in group B,which were significantly higher than those of 97.80±14.43,32.80±8.10 in group C and those of 31.40±13.41,8.40±4.30 in group D (P<0.01).The CFU-GEMMs were 45.60±8.51 in group A and 42.60±7.03 in group B,which were significantly higher than those of 20.80±6.96 in group C and those of 7.80±6.06 in group D (P<0.05).The BFU-MK was 12.80±4.42 in group A and 11.00±2.74 in group B respectively,which were significantly higher than that of 1.00±0.55 in group D (P<0.05).The CFU-E in group B 17.20±4.03 was significantly higher than that of 5.60±2.87 in group D (P<0.05).Meanwhile compared with group A and group E,no significant difference was found (P>0.05).By the Kendall test,there were negative correlations between the level of PRA serum and the total colonies,CFU-GM on day 7,the total colonies,CFU-GM,CFU-GEMM,BFU-E,BFU-MK on day 14 (tau-b=-0.793,-0.849,-0.808,-0.804,-0.645,-0.674,-0.624,P<0.01).There was a negative correlation between the level of PRA serum and CFU-MK on day 14 (tau-b=-0.466，P<0.05).CONCLUSION: PRA sera inhibit the colony in the colony cultures of the hematopoietic stem cells/progenitor cells in cord blood.The inhibition depends on the level of PRA sera.The higher the level of PRA sera,the stronger the inhibition is observed in our study.     

Retarding effect of simvastatin on artery remodeling induced by high-salt and high-fat diet in rats

AIM: To investigate the effect of simvastatin intervention on the changes of blood pressure, serum lipid fluctuation and aortic configuration induced by high-sodium and high-fat diet in rats. METHODS: Sixty adult male SD rats were randomly divided into 5 groups (n=12): control (N)group, high salt (S)group, high fat (F) group, high salt+ high fat (SF) group and high salt+high fat + simvastatin (T) group. After fed for 16 weeks, the rats were subject to determine blood pressures and serum concentrations of triglycerides (TG),total cholesterol(TC) and soluble CD40 ligand (sCD40L). The expression of CD40/CD40L in the root of ascending aorta was detected by immunohistochemical method. The thickness of intima media in the ascending aorta as well as the ratio of lumen area/total vascular area were measured and calculated after HE staining. RESULTS: In S group, F group and SF group, systolic blood pressure was significantly higher than that in N group (P<0.01). Systolic blood pressure in T group were slightly higher than that in N group with statistical significance and significantly lower than that in SF group. The serum concentrations of TG and TC in F group and SF group were significantly higher than those in N group and T group (P<0.01), and no significant difference among S group, N group and T group was observed. In S group, F group and SF group, the serum concentrations of sCD40L were higher than that in N group and T group (P<0.05), meanwhile that in SF group was also higher than that in S group and F group (P<0.05). However, no significant difference of sCD40L concentration between S group and F group as well as N group and T group was observed. The expression of CD40/CD40L in the ascending aorta in S group, F group and SF group was higher than that in N group and T group (P<0.05), and that in SF group was also higher than that in S group and F group (P<0.05).No significant difference of CD40/CD40L expression between S group and F group as well as N group and T group was observed. The thickness of intima media in S group, F group and SF group was significantly thicker than that in N group (P<0.01), and no significant difference of the intima media thickness between T group and N group was observed. The ratio of lumen area/total vascular area in S group, F group and SF group was smaller than that in N group (P<0.05), and no significant difference of the ratio between T group and N group was found. CONCLUSION: Feeding high-fat and high-salt diet leads to blood pressure elevation, induces atherosclerosis, increases serum concentration of sCD40L and enhances the expression of CD40/CD40L in arterial tissues. The combination of the stimuli has stronger effect than a single factor. Statins protect the arterial tissues against atherosclerosis by decreasing the level of serum sCD40L and inhibiting the arterial expression of CD40/CD40L.     

Changes in plasma neurotension level of patients with coronary heart disease and its clinical significance

AIM: To investigate the plasma neurotensin(NT) concentration in patients with coronary heart disease: acute myocardial infarction(AMI),unstable angina(UA),stable angina pectoris(SAP), old myocardial infarction (OMI), and to study the relationship between the plasma NT level and the myocardial ischemia . METHODS:The plasma NT concentration of 30 patients with AMI,32 pat ients with UA,35 patients with SAP,31 pat ients with OMI and 32 normal controls were determined by radioimmunoassay(RIA). RESULTS: The plasma NT level in patients with AMI(24 h),in patients with UA when angina attacked is significantly higher than that of healthy controls. The plasma NT level in patients with SAP, in patients with OMI is not significantly different from that of healthy controls. The NT level of patients with UA when angina attacked is significantly higher than that after 2 weeks treatment (P＜0.01). The NT level of AMI patients rose from early period and reached peak value at 24 h .It began to decline at 48h,and restored to normal level at 72h. CONCLUSION: When acute myocardial ischemia occured in patients with coronary heart disease, the plasma NT level was elevated. This suggests NT may have participated in the pathophysiological course of myocardial ischemia.     

Influence of leptin on intestinal function and its protective effect on hepa tic and renal functions after sepsis

AIM: To detect the effect of sepsis on hepatic,renal functions and corresponding enzymes in intestine of mice,and to explore the role of leptin in acute inflammation.METHODS: A mice model of sepsis was made by cecum ligation and perforation,and 96-well spectrophotometry was used to detecte the levels of alanine aminotransferase (ALT),uric acid (UA) and activities of myeloperoxidase (MPO),glutathin-S-transferase (GST),xanthine oxidase (XOD),superoxide dismutase (SOD) in serum and intestinal homogenized fluids,respectively.Hematoxylin-eosin staining was used simultaneously to check the histopathologic changes of intestine.RESULTS: Compared with sham group (330.12 μmol/L±94.15 μmol/L),serum UA level (521.92 μmol/L±91.86 μmol/L) at 6 h after sepsis was significantly higher.12 h after sepsis,both serum ALT (83.55 U/L±40.44 U/L) and UA (474.03 μmol/L±75.22 μmol/L) were significantly higher than those in sham group (66.23 U/L±16.80 U/L and 320.95 μmol/L±99.14 μmol/L,respectively).12 h after leptin injection (0.1 mg/kg,ip) or indomethacin injection (2 mg/kg,ip),the serum ALT and UA levels significantly decreased (vs sepsis group,P<0.05).Moreover,the activities of MPO,GST,XOD and SOD in intestine were changed at different degrees.CONCLUSION: During the process of sepsis,trace dose of leptin injected peritoneally significantly improves and stabilizes the hepatic and renal functions.The mechanisms may be related with those intestinal enzymes associated with metabolism of free radicals,mercapto group and purine.Indomethacin exerts a similar role as leptin though at much higher dose.     

Effects of Retinervus luffae fructus on mRNA expression of low-density lipoprotein receptor in hyperlipidemia mice

AIM: To observe the effects of Retinervus luffae fructus (RLF) on mRNA expression of low-density lipoprotein receptor (LDL-R) in hyperlipidemia mice. METHODS: Mice were fed with high fat diet to induce a hyperlipidemia model. By using xuezikang, a Chinese medicine, as a positive control, the effect of RLF on serum total cholesterol (TC) and level of low density lipoprotein cholesterol (LDL-C) in mice were observed. The liver total RNA was extracted by Trizol method. The LDL-R mRNA expression was determined by RT-PCR. RESULTS: (1) The levels of TC ［(5.71±0.82) mmol/L］ and LDL-C ［(3.99±1.12) mmol/L］ in hyperlipidemia (HPL) group were higher than those in control (P<0.01). The levels of TC ［(3.65±0.28) mmol/L］ and LDL-C ［(2.74±0.54) mmol/L］ in RLF treatment group, and the levels of TC ［(3.94±0.65) mmol/L］ and LDL-C ［(3.00±0.23) mmol/L］ in positive control (PC) group were lower than those in HPL group (P<0.01). (2) The level of hepatic LDL-R mRNA expression was lower in HPL group than that in control group (P<0.01). Compared to HPL group, significant increases in hepatic LDL-R mRNA expression in RLF treatment group and PC group (P<0.01) were observed. CONCLUSION: Retinervus Luffae Fructus exerts obviously lipid-lowering effect and enhances the hepatic LDL-R mRNA expression in experimental hyperlipidemia mice.     

Effects of hypertriglyceridemia and fenofibrate on CD40L expression in platelets

AIM: To observe the effects of hypertriglyceridemia and fenofibrate on CD40L expression in platelets in vitro and in vivo. METHODS: In vivo experiments, according to its own strict standards, 20 patients were respectively selected for hypertriglyceridemia group and control group, before and after treatment of fenofibrate for hypertriglyceridemia patients. The CD40 ligand positive rates of platelets by flow cytometry and plasma soluble CD40 ligand by ELISA were examined under the same conditions as control group. The CD40L and sCD40L in each group were compared. In in vitro experiments, all 6 objects plasma was chosen in the same condition except for triglyceridemia, after the co-incubation of these plasma with the same healthy platelets was performed and the interference with wy14643, the CD40 ligand positive rate of platelets by flow cytometry and total platelets CD40 ligand protein content by Western blotting were examined under the same conditions in all objects. The CD40L positive rate and total CD40L content in each group were compared, respectively. RESULTS: The platelet CD40L positive rate and plasma sCD40L concentration in hypertriglyceridemia group were significant higher than those in control group (P<0.01). Followed the TG concentration decreased, the platelet CD40L positive rate and plasma sCD40L concentration decreased after the treatment of fenofibrate, the same as the total platelets CD40L content which was significant higher in hypertriglyceridemia group than that in control group in vitro (P<0.05). No effect of wy14643 on the total CD40L content expression was observed in vitro. CONCLUSION: Hypertriglyceridemia plasma stimulates immune-activation of platelets both in vitro and in vivo. sCD40L may mainly come from CD40L on platelet membrane. PPARα activator of fenofibrate may inhibit the immune-activation of platelets by reducing the concentration of plasma TG, but PPARα activator WY14643 cant inhibit the expression of CD40L and CD40L in vitro.     

Correlation of serum uric acid level with carotid plaques and arterial stiffness in patients with essential hypertension

AIM：To study the correlation of serum uric acid (UA) level with carotid plaques and arterial stiffness in the patients with essential hypertension (EH), and to explore the predictive value of serum UA for evaluating EH preclinically. METHODS：A total of 92 patients with EH and 30 healthy individuals were enrolled. The value of UA and other indicators were detected. B-mode ultrasound examination was performed to measure the common carotid artery intima-media thickness (IMT) and the sites of plaque in the internal carotid-artery, external carotid artery and carotid bifurcations. Carotid-femoral arterial pulse wave velocity (CFPWV) was assessed by Complior atherosclerosis measurement instrument. RESULTS：The serum level of UA in the patients with EH was higher than that in control group ［(361.51±83.81） μmol/L vs (317.03±62.22) μmol/L, P<0.05］. The mean value and abnormal rate of IMT between hypertension group and control group were significant difference ［(0.69±0.14) mm vs (0.60±0.12) mm, 42.39% vs 10.00%, P<0.05］. In 92 EH patients, 45 cases had carotid plaques. These 45 cases were divided into 3 groups according to the plaque severity, among which the serum UA level had statistically significant differences ［(285.25±78.41） μmol/L, （341.19±63.99） μmol/L and （401.33±88.49） μmol/L, P< 0.05］. Compared with rigid plaque group (n=34), the serum UA level in soft plaque group (n=11) was significantly higher ［(389.00±69.45) μmol/L vs （323.03±72.71） μmol/L, P<0.05］. A stepwise multiple linear regression analysis demonstrated that age (r=0.414), systolic blood pressure (r=0.224), pulse pressure (r=0.270) and uric acid (r=0.219) were predisposed factors for higher CFPWV (P<0.05). CONCLUSION：UA is one of the risk factors causing hypertension. Serum UA level may reflect the severity and stability of carotid plaques. The increased arterial stiffness is closely related to the increased serum UA level in EH.     

Effects of pentoxifylline on ventricular remodeling and cardiac function of dilated cardiomyopathy rats

AIM: To explore the effects of pentoxifylline (PTX) on ventricular remodeling and cardiac function in dilated cardiomyopathy (DCM) rats.METHODS: Lewis rats were randomly allocated to a myocin-induced dilated cardiomyopathy (DCM) group receiving saline (n=10), a DCM group receiving PTX (PTX group; 25 mg·kg^-1·d^-1, ip, for 30 days, n=10) or healthy control group (n=10). The levels of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and IL-10 in the blood plasma were analyzed by ELISA. The extent of fibrosis was estimated using Massons staining and immunohistochemistry analyses. Cardiac structure and function were measured by echocardiography.RESULTS: PTX decreased plasma levels of TNF-α and IL-6, and increased IL-10 level in DCM animals compared with DCM group ［TNF-α: (7.21±0.24) μg/L vs (19.30±1.31) μg/L, P<0.01; IL-6: (119.60±36.58) ng/L vs (189.50±13.25) ng/L, P<0.05; IL-10: (41.26±3.27) μg/L vs (32.45±4.32) μg/L, P<0.05］. Collagen volume fraction (CVF), perivascular collagen area (PVCA) and collagen Ⅰ/Ⅲ ratio were lower in PTX group than those in DCM group ［CVF: (16.45±3.01)% vs (23.33±4.43)%, P<0.05; PVCA: 4.58±2.10 vs 13.74±4.29, P<0.05; Ⅰ/Ⅲ ratio: 2.84±0.67 vs 4.22±0.54, P<0.01］. Left ventricular end-diastolic dimension reduced ［(6.11±0.51) mm vs (6.46±0.28) mm, P<0.05］ and left ventricular ejection fraction elevated ［(77.29±5.20)% vs (62.73±10.11)%, P<0.01］ by PTX compared with DCM.CONCLUSION: PTX modulates plasma levels of inflammatory cytokines, delays the ventricle remodeling and improves the heart function in DCM rats.     

Serum sCD44s and sCD44v6 levels in breast cancer patients

AIM: To explore the clinical significance of detecting sCD44s and sCD44v6 in breast carcinoma. METHODS: Levels of serum soluble CD44 standard (sCD44s) and CD44 variant 6(sCD44v6) were detected by ELISA in 38 cases of breast cancer, 15 cases of benign breast diseases and 40 normal controls. RESULTS: The serum levels of sCD44s and sCD44v6 were significantly higher in patients with breast cancer than those with benign disease or normal controls. The serum concentrations of sCD44s and sCD44v6 in patients with stage Ⅲ, Ⅳ were significantly higher than those in patients with stageⅠ, Ⅱ(P＜0.01) .The level of sCD44v6 decreased markedly after one week operation and even more decreased after two weeks operation. The level of sCD44s was decreased significantly after two weeks operation. CONCLUSION: Serum levels of sCD44s and sCD44v6 may be a useful marker in the diagnosis and treatment of breast cancer. The changes in the levels of serum sCD44s and sCD44v6 may be the result of tumor burden, hence implicated in the prognosis of cancer patients.     

Prevention of isinglass on the chronic atrophic gastritis in rats and its mechanism

AIM: To evaluate the effect of isinglass on chronic atrophic gastritis(CAG) in rats and its mechanism. METHODS: An animal model of CAG in accordance with the previous experience of combined administration of 60% ethanol, 20 mmol/L sodium deoxycholate and 0.1% ammonia water was established in SD rats. Isinglass was used as preventive therapy while we were establishing CAG rat model. Finally all the rats were executed and pathologic changes of the gastric mucosa were studied by gross appearance and microscopy and serum epidermal growth factor (EFG) and growth hormone(GH) contents were tested. RESULTS: In each isinglass prevention group, inflammation grade of gastric antrum was less than that in model group (P<0.01) while the mean ratio of the thickness of gastric mucosal gland and muscularis mucosa (L1/L2), the number of gastric glands in 1 mm lengths of mucosal layer in longitudinal sections were much better than those in model group (P<0.01).They were very close to normal control group (P>0.05). The expression of proliferating cell nuclear antigen (PCNA) in gastric mucosa and serum EFG level were higher than those in model group (P<0.01, P<0.05), but serum GH content showed no different between isinglass prevention group and model group. CONCLUSION: Isinglass preventes the gastric mucosal atrophy in the CAG model. Its mechanism may be related to the effects of decreasing the gastric mucosal damage， promoting the cell proliferation and increasing of internal EFG secretion.     

Effect of hypoxia on persistent sodium current in ventricular myocytes from 3-week infarcted rat heart

AIM: To investigate the effect of hypoxia on persistent sodium current (INap) in single ventricular myocyte isolated from acute myocardial infarction (AMI) heart of rats and to study the mechanisms of cardiac arrhythmias that occur after AMI. METHODS: AMI model was induced by ligating the left anterior descending coronary artery in rats. The whole-cell patch clamp technique was used to record the current in epicardial myocytes in infarcted region from rats at 3 week after AMI. RESULTS: In normoxic conditions, the current density of INap in cardiomyocytes of fake operation (FO) and AMI hearts was 0.144±0.022 pA/pF (n=9), 0.121±0.013 pA/pF (n=9，P<0.01)， respectively, which was blocked by tetrodotoxin (TTX). The amplitude of INap was gradually increased with the prolongation of hypoxia time, but the increase in extent of INap in FO cells was significant bigger than that in AMI cells. The INap was blocked by 1 mmol/L glutathione. CONCLUSIONS: After AMI, the amplitude of INaP in infarcted and noninfarcted myocardium showed differences both in normoxic and hypoxic conditions, which increased dispersion of repolarization. This may be one of the reasons of reentrant ventricular arrhythmias that occur after AMI.     

Effect of transmyocardial laser revascularization on myocardial lactatic metabolism and mitochondria of myocardial cells

AIM: We studied the therapeutic effect and mechanism of transmyocardial laser revascularization (TMLR) for the acute myocardial ischemia (AMI). METHODS: 18 dogs were divided randomly and evenly into the control group, the AMI group and the TMLR group. A continuous wave Nd: YAG laser was used for TMLR. Concentration of lactate in artery and coronary sinus (A.Lat and CS.Lat), myocardial metabolic rate of lactate acid (MLR) and myocardial lactate extraction (MLE) were measured before the left anterior descending coronary artery (LAD) ligation and 60 min after the LAD ligation. Myocardial biopsy was made 4 h after the LAD ligation to quantitatively observe the shape and number of mitochondria in myocardial cells by a electric microscope. RESULTS: 60 min after the LAD ligation, CS.Lat were (7.63±4.27) mmol/L in the AMI and (5.78±3.98) mmol/L in the TMLR, respectively (P<0.05); MLR were (0.03±0.01) mmol·100 g^-1 myocardium·min^-1 in the AMI and (0.06±0.02) mmol·100 g^-1 myocardium·min^-1 in the TMLR, respectively (P<0.05); MLE were (12.04±3.04) in the AMI and (21.84±8.49)% in the TMLR, respectively (P<0.05). The volume density of mitochondria were (27.51±7.93)% in the AMI and (31.26±3.85)% in the TMLR, respectively (P>0.05). The area density of mitochondria were (1.25±0.18) μm^-1 in the AMI and (1.64±0.28) μm^-1 in the TMLR, respectively (P<0.01). The number density of mitochondria were (0.10±0.03) μm^-3 in the AMI and (0.18±0.05) μm^-3 in the TMLR, respectively (P<0.01). The average volume of mitochondria were (5.27±2.85) μm³ in the AMI and (2.80±0.54) μm³ in the TMLR, respectively (P<0.05). The average diameter of mitochondria were (2.06±0.36) μm in the AMI and (1.78±0.12)μm in the TMLR, respectively (P＜0.05). CONCLUSION: The study suggests that TMLR may effectively improve myocardial lactatic metabolism and protect the myocardial cells from ischemic injury in dogs with the AMI.     

Effect of mycophenolic acid on T lymphocyte proliferation and cytokine expression in vitro

AIM: To investigate the effect of mycophenolic acid (MPA) alone or in combination with anti B7-1 mAb on proliferation of T lymphocytes and the possible mechanisms. METHODS: The proliferation of T lymphocytes was detected by BrdU incorporation method. The expressions of IL-2, IFN-γ and IL-10 in mRNA and protein levels were detected by RT-PCR and ELISA, respectively. RESULTS: (1) MPA markedly inhibited the T lymphocyte proliferation as compared with control (P<0.01). (2) MPA significantly inhibited the levels of IL-2 and IFN-γ (42.73 ng/L±14.64 ng/L vs 99.70 ng/L±9.15 ng/L, P<0.01; 7.87 ng/L±4.22 ng/L vs 82.42 ng/L±25.55 ng/L, P<0.05), and significantly increased content of IL-10 compared with control (770.95 ng/L±126.85 ng/L vs 545.71 ng/L±22.45 ng/L, P<0.05). MPA in combination with anti B7-1 mAb obviously enhanced the content of IL-10 compared with MPA alone (941.90 ng/L±56.61 ng/L vs 770.95 ng/L±126.85 ng/L, P<0.05). (3) The expression levels of IL-2 and IFN-γ mRNA in the MPA group were obviously lower than those in control (0.74±0.10 vs 1.17±0.15, 0.52±0.05 vs 0.75±0.12, P<0.01). MPA in combination with anti-B7-1 mAb showed a statistically significant increase in IL-10 mRNA expression (1.28±0.06 vs 0.84±0.09, P<0.01) as compared with MPA alone. CONCLUSION: MPA induces the changes of cytokine expressive spectrum and the Th1 and Th2 shift might be involved in the immunosuppressive effect. The combination of MPA with anti B7-1 mAb might have a synergic effect.     

Effects of spermine on myocardial ischemia/ reperfusion injury in rats

AIM: To observe the effect of exogenous spermine (low concentration) on myocardial ischemia/reperfusion injury in rats.METHODS: 40 Wistar rats were randomly divided into 4 groups: sham- operation group (Sham), ischemic reperfusion group (I/R), spermine group (Sp) and natural saline group (NS). The model of ischemic/reperfusion injury was established by ligating rat coronary artery. In Sp group, spermine (0.5 mmol/L, 2 mL/kg) was injected slowly into rat vein. During the process, we recorded the electrocardiogram and the LV functional parameters, assayed the levels of SOD, LDH, NO and MDA in serum, and examined the ultrastructure of the myocardium. RESULTS: In I/R group, the incidence of arrhythmia was 90%, myocardial ultrastructure was injured seriously, values of LVSP and ±dp/dtmax decreased, levels of LDH, NO and MDA increased while SOD activity decreased (P<0.05 or P<0.01, compared with Sham group). Compared with I/R and NS group, all those indexes in Sp group changed significantly (P<0.05 or P<0.01). CONCLUSION: Exogenous spermine alleviates myocardial ischemia/ reperfusion injury in rats. The mechanism may be related to its antioxidant effect and relieving the injury caused by oxygen free radical.     

Protective effect of Tongxinluo on mini-swine model of acute myocardial infarction and reperfusion damaged by oxidative stress

AIM: To assess the degree of oxidative damage during acute myocardial infarction and reperfusion, and to clarify the protective effect of Tongxinluo in mini-swine model. METHODS: Thirty mini-swines were randomized into 5 study groups: sham group, model group, low dose (0.05 g·kg-1·d-1), medium dose (0.2 g·kg-1·d-1) and high dose (0.5 g·kg-1·d-1) of Tongxinluo groups (pretreated with Tongxinluo for 3 d). Animals except in sham group were subjected to 3 h of coronary occlusion followed by 1 h of reperfusion. Concentrations of total antioxidative capability (T-AOC), total superoxide dismutase (T-SOD), reduced glutathione (GSH) and malondialdehyde (MDA) in blood sample and the myocardium were measured. RESULTS: (1) T-AOC, T-SOD and GSH in serum significantly decreased (all P<0.05), while MDA significantly increased (P<0.01) at 3 h after AMI in comparison with those at baseline. Compared to those at 3 h after AMI, the contents of T-AOC, T-SOD and GSH at 1 h after reperfusion significantly decreased (all P<0.01), accompanied by increase of MDA (P<0.01). (2) Compared to those in normal area, levels of T-AOC, T-SOD and GSH in reperfusion myocardium decreased significantly (all P<0.01) and MDA increased significantly (P<0.01). T-AOC, T-SOD and GSH in no-reflow myocardium further decreased (all P<0.01) and MDA increased (P<0.01) as compared to those in reperfusion myocardium. (3) Compared to model group, medium dose of Tongxinluo increased the contents of T-AOC and T-SOD and reduced MDA production in serum at 3 h after AMI (all P<0.05), while medium dose of Tongxinluo increased T-SOD level at 1 h after reperfusion (P<0.05). High dose of Tongxinluo increased the levels of T-AOC and T-SOD and decreased MDA content in serum at 3 h after AMI and 1 h after reperfusion (all P<0.05). (4) The medium dose of Tongxinluo increased T-AOC content (P<0.05) and reduced MDA (P<0.05) in reperfusion myocardium, while high dose of Tongxinluo increased T-AOC, T-SOD and GSH (all P<0.05), reduced MDA (P<0.01) in reperfusion myocardium, and also increased T-AOC, T-SOD (all P<0.05), reduced MDA (P<0.01) in no-reflow area as compared to those in model group. CONCLUSION: Impairment of antioxidant defense system in vivo and imbalance of redox homeostasis in myocardium region might play an important role in the pathogenesis of no-reflow after myocardial acute infarction following reperfusion. Tongxinluo protects myocardium from reperfusion injury by improving antioxidant defense and attenuating oxidative damage.