Effect of hydrogen sulfide on H₂O₂-stimulated primary neonatal rat cardiomyocytes / 中华心血管病杂志

<p><b>OBJECTIVE</b>To investigate the effects of hydrogen sulfide (H2S) on H2O2-stimulated primary neonatal rat cardiomyocytes and related mechanism.</p><p><b>METHODS</b>Primary neonatal rat cardiomyocytes were treated with various concentrations of H2O2 (10, 100, 1000 µmol/L) for 24 h to establish the oxidative stress-induced cell injury model after 3 days' conventional culture. In addition, different concentrations of NaHS (1, 10, 100 µmol/L) were added to cardiomyocytes in the absence and presence of 100 µmol/L H2O2 for 24 h. The viability of cardiomyocytes was measured by MTT assay. The SOD vitality was measured by xanthine oxidase method and MDA content was determined by thiobarbituric acid colorimetric method. LDH activity was measured by chemical colorimetric method. The percentage of apoptotic cells was assessed by flow cytometry (FCM). The mitochondrial membrane potential (MMP) was analyzed by rhodamine 123 (Rh123) staining and photofluorography. The level of reactive oxygen species (ROS) in cardiomyocytes was measured by DCFH-DA staining and photofluorography.</p><p><b>RESULTS</b>Cell viability and SOD vitality were significantly reduced while MDA content and LDH activity were significantly increased with increasing H2O2 concentrations. These effects could be partly reduced by cotreatment with H2O2 in a concentration-dependent manner (all P < 0.05). Compared with control group, the DCF fluorescence intensity significantly increased in the 100 µmol/L H2O2 group (P = 0.003), which could be attenuated by NaHS in a dose-dependent manner. Compared with control group, the MMP significantly decreased in the 100 µmol/L H2O2 group (P = 0.000), which could be partly reversed by cotreatment with NaHS in a dose-dependent manner. Moreover, H2O2 treatment also significantly reduced 100 µmol/L H2O2 induced apoptosis in a dose-dependent manner.</p><p><b>CONCLUSION</b>H2S protects primary neonatal rat cardiomyocytes against H2O2-induced oxidative stress injury through inhibition of H2O2 induced overproduction of ROS, dissipation of MMP and apoptosis.</p>

Physiological testosterone retards cardiomyocyte aging in Tfm mice via androgen receptor-independent pathway / 中国医学科学杂志(英文版)

<p><b>OBJECTIVE</b>To determine whether testosterone modulates markers of cardiomyocytes aging via its classic androgen receptor (AR)-dependent pathway or conversion to estradiol.</p><p><b>METHODS</b>Male littermates and testicular feminized (Tfm) mice were randomly separated into 4 experimental groups littermate controls (n=8), Tfm mice (n=7), testosterone-treated Tfm mice (n=8), and Tfm mice treated with testosterone in combination with the aromatase inhibitor anastrazole (n=7). Cardiomyocytes were isolated from mouse left ventricles, the activity of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), and the amount of malondialdehyde (MDA) were measured using colorimetry method, and expression of p16(INK4α) and retinoblastoma (Rb) proteins were detected by Western blotting.</p><p><b>RESULTS</b>The SOD and GSH-Px enzyme activities of cardiomyocytes were decreased, and the MDA levels and the expression of p16(INK4α) and Rb proteins were increased in Tfm mice compared with control mice. An increase was observed in the activities of SOD and GSH-Px enzyme as well as a decrease in MDA levels and the expression of p16(INK4α) and Rb proteins in the testosterone-treated Tfm mice. After co-treatment with anastrazole in Tfm mice, these improvement were partly inhibited.</p><p><b>CONCLUSION</b>Physiological testosterone replacement can delay cardiomyocyte aging in Tfm mice, an effect that is independent of the AR pathway and in part conversion to estradiol.</p>

Effects of policosanol combined with simvastatin on serum lipids and sex hormones in male patients with hyperlipidemia / 中华心血管病杂志

<p><b>OBJECTIVE</b>To evaluate the effects and safety of policosanol combined with simvastatin on serum lipids and sex hormones in male patients with hyperlipidemia.</p><p><b>METHODS</b>This randomized, single-blinded, placebo-controlled study included 120 male patients with hyperlipidemia. Patients were divided randomly into treatment group(n = 60) and control group(n = 60). Patients in the treatment group were administrated with simvastatin (40 mg/d) plus policosanol (20 mg/d),and those in the control group were treated with simvastatin (40 mg/d) plus placebo (20 mg/d). The values of total cholesterol(TC), triglyceride(TG), high density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol(LDL-C), testosterone(T) and estradiol (E2) were assessed before and after 16 weeks treatment.Drug-induced adverse effects were observed.</p><p><b>RESULTS</b>Baseline characteristics were similar between groups. TC,TG, LDL-C were (5.74 ± 0.99) , (1.62 ± 0.69), (3.60 ± 0.56) mmol/L in the treatment group at baseline and significantly reduced after 16 weeks treatment (4.57 ± 0.58), (1.54 ± 0.55), (2.68 ± 0.38) mmol/L (all P < 0.05). TC, LDL-C were (5.99 ± 0.93) , (3.76 ± 0.42) mmol/L in the control group at baseline and significantly reduced after 16 weeks treatment (5.03 ± 0.59) , (2.98 ± 0.28) mmol/L (all P < 0.05) while TG remained unchanged post 16 weeks therapy in the control group. Simvastatin plus policosanol achieved a significantly greater reduction in LDL-C and TC than simvastatin plus placebo (P < 0.05). HDL-C,T and E2 were similar before and after 16 weeks treatments in both groups (P > 0.05) .The adverse reactions were similar between the two groups, most of them were mild and happened at the beginning of drug therapy and could be well tolerated.</p><p><b>CONCLUSION</b>Simvastatin/policosanol produces greater decreases in TC, LDL-C than simvastatin/placebo without resulting more side effects and changes on sex hormones.</p>

Effect of physiological doses of testosterone on mitochondrial DNA deletion in castrated mice / 南方医科大学学报

<p><b>OBJECTIVE</b>To evaluate the effect of physiological doses of testosterone on mitochondrial DNA (mtDNA) deletion in the aortic vascular wall of castrated C57BL/6J mice.</p><p><b>METHOD</b>Twenty-four male C57BL/6J mice were randomized into normal control group (n=8), castrated+placebo group (castrated group, n=8), and castrated+physiological doses (1 mg/kg every 3 days) of testosterone group (n=8). The mice were fed normally for 3 months along with 8 mice with natural aging (18 months old), after which blood samples were obtained from all the groups for measurement of testosterone concentrations. The aortic mtDNA was extracted to analyze the deleted fragments using nested PCR, and fragments with deletions were purified and identified by sequence analysis.</p><p><b>RESULTS</b>Compared with the normal control group, the castrated group showed a significantly higher optical density ratio of the deletions [(18.1713 ∓ 2.4317)% vs (36.8475 ∓ 3.3365)%], but no significant difference was found between the castrated and natural ageing group [(42.3075 ∓ 3.6556)%]. The castrated+testosterone showed a lowered optical density ratio of (23.6488 ∓ 2.7634)% as compared with the castrated and natural ageing group, but a similar one with the normal control group. Sequence analysis identified 4 different types of deletions in the aging aorta at 3713, 3864, 4236, and 4415 bp, and the presence of direct repeats was confirmed to flank the deletions.</p><p><b>CONCLUSIONS</b>Multiple mtDNA deletions occur in ageing mice at a higher rate than in young mice. Testosterone deficiency is associated with increased aortic mtDNA deletions, which can be decreased by physiological doses of testosterone.</p>

Effects of simvastatin on plasma SOD, MDA and 8-iso-PGF2α in patients with stable angina / 南方医科大学学报

To observe the effects of simvastatin on plasma superoxide dismutase (SOD), malonaldehyde (MDA) and 8-iso-prostaglandin F2α (8-iso-PGF2α) as well as uric acid (UA) and serum lipids in patients with stable angina. METHODS Eighty-five patients with stable angina were divided into 4 groups, including hyperlipemia treatment group (HLT), hyperlipemia control group (HLC), normolipemia treatment group (NLT), and normolipemia control group (NLC). All the patients received routine treatment according to the guideline of CHD treatment, and those in the treatment groups were given Simvastatin (40 mg) every night, whereas those in the control group received placebo for 3 months. Before and after the treatments, the levels of plasma 8-iso-PGF2α were measured by enzyme-linked immunosorbent assay, and the plasma levels of SOD and MDA were detected by colorimetric method. LDL, HDL, TC, TG, and UA were also measured biochemically. RESULTS Compared with the control group, both of the treatment groups showed significantly increased levels of SOD and decreased MDA, 8-iso-PGF2α, UA and plasma lipids after the treatments (P<0.05). CONCLUSION In patients with coronary heart disease, simvastatins can decrease plasma lipids, inhibit lipid peroxidations, and promote the clearance of free radicals, thereby alleviating the oxidative stress.

Effect of a new arginine analog on isoproterenal-induced Ca2+ transients in cultured rat cardiac myocytes / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effects of a novel tripeptide analog of arginine on isoproterenol (ISO), a beta-adrenergic receptor agonist, induced the change in concentration transient cytosolic free calcium in cultured neonatal rat cardiac myocytes (CMs).</p><p><b>METHODS</b>The expression of inducible nitric oxide synthase (iNOS) was induced in cultured neonatal rat CMs by stimulation with lipopolysaccharide (LPS) and interleukin-6 (IL-6) for 24 h, and quantitatively measured using Western blotting. The CMs were incubated in the presence of the new arginine analog for 6 h and the changes of fluorescence signal of free calcium in response to isoproterenol (ISO) treatment were measured under laser scanning confocal microscope.</p><p><b>RESULTS</b>Incubation of the CMs for 24 h in the presence of IL-6 and LPS resulted in significantly increased nitric oxide (NO) production, and also in increased iNOS protein accumulation in the cells. Specific inhibition of iNOS by the new arginine analog substantially inhibited NO production and increased the peak value of ISO-induced Ca2+ transient.</p><p><b>CONCLUSION</b>The new arginine analog strongly inhibits IL-6 and LPS-induced NO production and increases beta-adrenergic responsiveness in cultured neonatal rat CMs.</p>

Relationship between dehydroepiandrosterone and arteriosclerosis in premenopausal and postmenopausal women / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the correlation between dehydroepiandrosterone and arteriosclerosis in premenopausal and postmenopausal women.</p><p><b>METHODS</b>Forty premenopausal and 40 postmenopausal women were examined for serum concentrations of dehydroepiandrosterone and intima-media thickness of the carotid artery, and the serum concentrations of lipids, estrogen, endothelin, and E-selectin were also measured.</p><p><b>RESULTS</b>Compared with premenopausal women, the mean intima-media thickness was increased but dehydroepiandrosterone and estrogen levels were decreased in postmenopausal women. A significant inverse correlation was detected between the intima-media thicknesses and dehydroepiandrosterone level. The postmenopausal women had decreased antioxidation and elevated low-density lipoprotein level.</p><p><b>CONCLUSION</b>Arteriosclerosis is more likely to occur in women with low dehydroepiandrosterone level which causes decreased antioxidation and elevation of blood lipid levels.</p>

Ultrasound enhances microbubble-mediated gene transfection without affecting the cytoskeletons of endothelial cells / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effect of therapeutic ultrasound on enhancing albumin microbubble-mediated gene delivery and evaluate the cytoskeletal damages in endothelial cells (ECs).</p><p><b>METHODS</b>The ECs cultured in 6-well plates were transfected with the plasmid eGFP in the presence or absence of the microbubbles at different concentrations, followed by ultrasound exposure for 30 to 180 s at 2 MHz, with the mechanical index (MI) of 0.5-1.8. The gene transfection efficiency was evaluated by observing the green fluorescence of the cells, and the cytoskeletal damage was assessed using immunofluorescence staining 24 to 48 h after ultrasound exposure.</p><p><b>RESULTS</b>Within the MI range of ultrasound exposure between 0.50 and 1.00, the gene transfection efficiency was positively correlated to MI (P<0.001), and further increment of the MI failed to further increase the transfection efficiency. The duration of ultrasound exposure, within the range of 30-90 s, was also positively correlated to the gene transfection efficiency and microtubule fluorescence intensity(P<0.001), and prolonged exposure did not further enhance the effects. Variation of the MI and ultrasound exposure time within the above ranges did not cause significant changes in the florescence intensity of the microfilaments (P>0.05).</p><p><b>CONCLUSION</b>Albumin microbubbles in the presence of ultrasound exposure can substantially enhance the gene transfection efficiency due to therapeutic ultrasound-mediated microbubble destruction without causing obvious damage of the cytoskeletons, and allows safe and efficient nonviral gene delivery in gene therapy.</p>

Protective effects of estrogen on mitochondria in human umbilical vascular endothelial cells / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the protective effects of estrogen on the mitochondria in human umbilical vascular endothelial cells (HUVECs).</p><p><b>METHODS</b>HUVECs were exposed to H2O2 at 250 micromol/L for 4 h with or without pretreatment with 17-estradiol (E2) and ICI182780. Complex IV activity of the cells was measured with chromometry, and 2, 7-dichlorofluorescein diacetate (DCFH-DA) was used to determine intracellular reactive oxygen species (ROS). Intracellular adenosine triphosphate (ATP) level was quantified with a luciferin- and luciferase-based assay.</p><p><b>RESULTS</b>Compared to the blank control group, H2O2 caused a decrease in complex IV activity, intracellular ATP level, and the cell viability, but elevated intracellular ROS. E2 pretreatment of cells significantly attenuated these effects of H2O2 exposure. ICI182780 administered prior to E2 pretreatment antagonized the protective effects of E2 against H2O2 exposure.</p><p><b>CONCLUSION</b>E2 offers mitochondrial protective effects on HUVECs, which is mediated by the estrogen receptors.</p>

Levels of C-reactive protein and antibodies against oxidized low-density lipoprotein in patients with different types of coronary heart disease / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the relation of the levels of C-reactive protein (CRP) and antibodies against oxidized low-density lipoprotein (anti-oxLDL) to with acute coronary syndrome (ACS).</p><p><b>METHODS</b>The levels of CRP, anti-oxLDL and anti-LDL were measured and compared in 96 subjects including 26 with acute myocardial infarction (AMI), 29 with unstable angina pectoris (UAP), 20 with stable angina pectoris (SAP) and 21 control subjects to evaluate the relationship between CRP and anti-oxLDL.</p><p><b>RESULTS</b>Both CRP and anti-oxLDL levels in patients with ACS, including AMI and UAP, were significantly higher than those in SAP patients and the control subjects (P<0.05), but the level of anti-LDL showed no significant difference between the groups (P>0.05). There was significant positive correlation between the levels of CRP and anti-oxLDL (P<0.001).</p><p><b>CONCLUSION</b>The specific immune response to oxLDL may play an important role in the instability of plaque and the occurrence of ACS, and anti-oxLDL level may serve as an important specific marker for the instability of plaque.</p>

A new synthetic tripeptide inhibits L-arginine transport in macrophages / 南方医科大学学报

<p><b>OBJECTIVE</b>To observe the effect of a new synthetic tripeptide [Arg(NO(3))- Lys(OCH(3))- Arg(NO(3))] on L-arginine/NO pathway in the macrophage cell strain RAW246.7.</p><p><b>METHODS</b>The cultured macrophages exposed to lipopolysaccharide (LPS, 1 microg/L) treatment were randomly divided into 3 groups (n=6) and treated with distilled water, 1x10(-4) mol/L tripeptide and 1x10(-4) mol/L L-arginine, NG-monomethyl-L-arginine (L-NMMA) for 24 h, respectively. The macrophages were incubated for 24 h with LPS (1 microg/L) and in the presence of different concentrations of L-arginine (0 to 2 mmol/L), or in normal culture medium (containing 0.5 mmol/L L-arginine) for 24 h with LPS (1 microg/L) and in the presence of tripeptide of 0 to 10x10(-4) mol/L. The changes of [(3)H]-L-arginine transport and NO production from the macrophages were measured.</p><p><b>RESULT</b>NO release from macrophages incubated in the LPS-containing culture medium was 50 folds, and [(3)H]-L-arginine uptake 2.7 folds that in cells in normal culture medium. Tripeptide (1x10(-4) mol/L) inhibited [(3)H]-L-arginine transport and NO production by 67% and 71% respectively. The effect of tripeptide was stronger than L-NMMA (P<0.05). Extracellular L-arginine caused a concentration-dependent increase in nitrite production, which reached the maximum at concentrations above 0.5 mmol/L Km for nitrite production of 0.162+/-0.015 mmol/L and Vmax of 91.2+/-2.3 micromol/(24h.10(6) cells). L-arginine transport and NO production were inhibited by tripeptide, but their dose-dependent pattern of changes was different with EC50 of 0.21x10(-4) mol/L and 1.27x10(-4) mol/L, respectively.</p><p><b>CONCLUSIONS</b>Activation of macrophages with LPS induces nitrite accumulation in the culture medium, which is dependent on the presence of extracellular L-arginine. The tripeptide induces dysfunction of L-arginine/NO pathway in macrophages, potently inhibits L-arginine transport and competitively combine the active sites of nitric oxide synthase.</p>

Highly selective inhibition of inducible nitric oxide synthase in vitro by a tripeptide as a new arginine analog / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the inhibitory effect of a tripeptide, a new arginine analog, on nitric oxide (NO) production and inducible nitric oxide synthase (iNOS).</p><p><b>METHODS</b>Macrophages challenged with lipopolysaccharide were cultured to test the inhibitory effect of the arginine analog of different concentrations on iNOS. Primarily cultured human umbilical vein endothelial cells (HUVECs) treated with insulin were used to test the effect of the analog on endothelial NOS (eNOS).</p><p><b>RESULTS</b>The new arginine analog significantly inhibited NO production in the macrophages in a dose-dependent manner, but had little effect on insulin-stimulated NO production in HUVECs. The new analog could significantly suppress iNOS activity, but had no significant inhibitory effect on constitutive NOS activity or eNOS activity. Western blot analysis showed that the new analog did not significantly affect the protein expression of iNOS.</p><p><b>CONCLUSION</b>The new analog is a NOS inhibitor with high selectivity on iNOS.</p>

Association of peripheral blood estradiol, progesterone and testosterone levels with irritable bowel syndrome / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the relation of peripheral blood estradiol, progesterone and testosterone levels with irritable bowel syndrome (IBS).</p><p><b>METHODS</b>Forty-eight patients with IBS identified according to Rome II diagnostic criteria and 30 healthy subjects as controls were analyzed for peripheral blood sex hormone levels by radioimmunoassay and corresponding software.</p><p><b>RESULTS</b>In male patients with IBS, blood testosterone level was significantly lower than that of the control group (P<0.05), but blood estradiol and progesterone showed no significant differences between the two groups (P>0.05). In the female patients, blood estradiol level was significantly lower than that of the control group (P<0.05), whereas blood progesterone and testosterone levels had no significant differences between the two groups (P>0.05).</p><p><b>CONCLUSION</b>Peripheral blood testosterone level in male IBS patients and estradiol level in female patients are lower than those of healthy subjects, suggesting that IBS might be associated with blood sex hormone disorder.</p>