ABSTRACT
Objective: Large-conductance calcium-activated potassium (BKCa) channel modulates vascular smooth muscle tone. In the present study, we tested the hypothesis that salt, one of the factors which significantly influence blood pressure (BP), can regulate BKCa activity and then elevate blood pressure. Methods: Male Sprague-Dawley rats aged 6 weeks were randomized into high salt diet group (HS) and control group, fed with high salt diet (containing 5% NaCl) and standard rat chow (containing 0.4% NaCl) respectively for 16 weeks. Tail systolic blood pressure (SBP), body weight (BW) and 24-hour urinary output were tested every 4 weeks. Content of urinary Na+ was detected using flame spectrophotometrical method. At the end of 16 weeks, all the rats were killed, the mesenteric arteries were obtained, and single mesenteric smooth muscle cells were isolated at once. The resting membrane potential (Em), the total potassium currents and the currents after perfusion with TEA solution of the cells were all recorded by whole cell patch clamp. The transcriptions of BKCa channel α and β1 subunits in mesenteric arterial vascular smooth muscle cells (VSMC) of each group were calculated by real-time RT-PCR. Results: There was no difference in SBP and BW at each stage between control group and HS group; the urinary Na+ level in HS animals was elevated significantly after 4 weeks. The negative values of Em in HS group VSMCs were reduced compared with those in the control group. Transcriptions of β1 subunit of BKCa channels were decreased in HS group, but α subunit transcriptions did not differ between the two groups. Whole cell potassium currents did not differ between HS and control groups, but BK Ca currents of HS group VSMCs were lower than those of control group ones. Conclusion: Even without elevating SBP, salt-loading can still modulate the expression and activity of BKCa channel in the mesenteric arterial VSMC and elevate vascular tone.
ABSTRACT
<p><b>OBJECTIVE</b>To study the clinical significance of serum matrix metalloproteinase-8 (MMP-8) concentration variation in patients with acute coronary syndrome (ACS).</p><p><b>METHODS</b>Enzyme-linked immunosorbent assay (ELISA) was employed to detect serum MMP-8 content in 80 ACS patients, including 43 with acute myocardial infarction (AMI), and 37 with unstable angina pectoris (UAP), as well as in 43 with stable angina pectoris (SAP) cases and 37 control subjects. The risk factors for atherosclerosis pertaining to age, sex, hypertension, body mass index, smoking, family history, diabetes, hyperlipidemia, etc. were evaluated statistically in each case.</p><p><b>RESULTS</b>Serum MMP-8 concentration was significantly higher in ACS group than in SAP and control groups (Plt;0.01). In ASC group, serum MMP-8 was much higher in AMI patients than in those with UAP (Plt;0.01), but similar between UAP and SAP groups (P>0.05). Logistic regression analysis identified serum MMP-8 concentration as the possible indicator of ACS (B=4.493, P=0.000), and particularly AMI (B=9.961, P=0.000). Linear correlation and linear regression analysis revealed that only neutrophils were associated with serum MMP-8 concentration variation (r=0.274, P=0.001).</p><p><b>CONCLUSIONS</b>Serum MMP-8 concentration is closely associated with ACS, particularly AMI, and may serve as an indicator for predicting ACS and AMI. Neutrophils may be connected with the variation of serum MMP-8 concentration, but not as the major factor.</p>
Subject(s)
Female , Humans , Male , Acute Coronary Syndrome , Blood , Diagnosis , Angina Pectoris , Blood , Diagnosis , Biomarkers , Blood , Enzyme-Linked Immunosorbent Assay , Logistic Models , Matrix Metalloproteinase 8 , Blood , Myocardial Infarction , Blood , DiagnosisABSTRACT
OBJECTIVE@#To detect the levels of index related to inflammation such as soluble CD40 ligand (sCD40L), neutrophil collagenase-8 (MMP-8), and pregnancy associated plasma protein-A (PAPP-A) , lipid peroxidation and autoimmune indexes such as oxidized low density lipoprotein (ox-LDL) and its antibody (ox-LDL Ab) in patients with coronary heart disease, and to investigate its relationship with acute coronary syndrome (ACS).@*METHODS@#Contents of sCD40L, MMP-8, PAPP-A, ox-LDL and ox-LDL Ab in the peripheral blood were measured by enzyme-linked immunosorbent assay from 109 patients with coronary heart disease including 36 acute myocardial infarction (AMI), 38 unstable angina pectoris (UAP), and 35 stable angina pectoris (SAP) and 36 controls without coronary heart disease.@*RESULTS@#The levels of each index in the peripheral blood of ACS patients (including AMI and UAP) were higher than those of SAP patients and controls (P 0.05). The levels of each index of SAP patients, except PAPP-A, were all higher than those of controls (P <0.05). All the indexes were helpful in diagnosis of ACS. The area under the ROC curve of each index is between 0.7 and 0.9.@*CONCLUSION@#The increase of sCD40L, MMP-8, PAPP-A, ox-LDL and ox-LDL Ab levels in peripheral blood may be related to the pathogenesis of ACS, and can be used as potential markers of unstable atherosclerosis plaque.