Single-Stranded DNA-Binding Protein 1 Abrogates Cardiac Fibroblast Proliferation and Collagen Expression Induced by Angiotensin II.

Angiotensin II (Ang II), an effective component of renin-angiotensin system, plays a pivotal role in cardiac fibrosis, which may further contribute to heart failure. Single-stranded DNA-binding protein 1 (SSBP1), a DNA damage response protein, regulates both mitochondrial function and extracellular matrix remodeling. In this study, we aim to investigate the role of SSBP1 in cardiac fibrosis that is induced by Ang II. We infused C57BL/6J mice with vehicle or Ang II and valsartan using implanted osmotic mini-pumps. Moreover, heart function was examined by echocardiography and cardiac fibrosis was analyzed via picrosirus red staining. The expression of COL1A1, COL3A1, SSBP1, p53, Nox1, and Nox4 was analyzed via qRT-PCR and/or immunoblots. The SSBP1 expression was manipulated via SSBP1 shRNA and pcDNA3.1/SSBP1 plasmids, while the p53 expression was enhanced via AdCMV-p53 infection. The exposure to Ang II increased the mouse heart weight, systolic blood pressure, interventricular septal thickness diastolic (IVSTD) and left ventricular end posterior wall dimension diastolic (LVPWD), which were counteracted by valsartan. While cardiac fibrosis was induced with Ang II treatment, it was relieved using valsartan. Furthermore, Ang II treatment caused mitochondrial dysfunction, oxidative stress, and down-regulated SSBP1 expression. The knockdown of SSBP1 increased cardiac fibroblast proliferation, collagen expression, and decreased p53 expression, which was impeded via SSBP1 overexpression. Moreover, the forced expression of p53 abated the fibroblast proliferation and collagen expression that was induced by Ang II. To summarize, SSBP1 was down-regulated by Ang II and implicated in cardiac fibroblast proliferation and collagen expression partly via the p53 protein.

Increased serum 2-oxoglutarate associated with high myocardial energy expenditure and poor prognosis in chronic heart failure patients.

Myocardial energy expenditure (MEE) and 2-oxoglutarate are elevated in chronic heart failure (CHF) patients compared with healthy controls. To explore whether 2-oxoglutarate could reflect the levels of MEE and predict the prognosis of CHF, 219 CHF patients and 66 healthy controls were enrolled. 2-Oxoglutarate was assayed with Liquid Chromatography-Mass Spectrometry/Mass Spectrometry (LC/MS/MS). CHF patients were divided into 4 groups according to interquartile range of MEE and followed for death or recurrent hospital admission due to CHF for the mean follow-up time 6.64±0.16months. 2-Oxoglutarate was increased in CHF patients compared with controls (P<0.01) and correlated with estimated glomerular filtration rate (r=0.142, P=0.036), age (r=-0.269, P<0.01) and MEE levels (r=0.307, P<0.01) in a multiple linear correlation analysis in CHF patients. Furthermore, 2-oxoglutarate (OR=3.470, 95% CI=1.557 to 7.730, P=0.002), N-terminal pro-B-type natriuretic peptide (OR=4.013, 95% CI=1.553 to 10.365, P=0.004), age (OR=1.611, 95% CI=1.136 to 2.283, P=0.007) and left ventricular ejection fraction (OR=7.272, 95% CI=3.110 to 17.000, P<0.001) were independently associated with MEE on multiple logistic regression analysis. Kaplan-Meier event curves showed that high 2-oxoglutarate levels were associated with adverse outcomes (Log Rank, Chi(2)=4.026, P=0.045). This study showed that serum 2-oxoglutarate is associated with MEE levels, which can be used as potential biomarkers for MEE, and it can reflect the clinical severity and short-term outcome of CHF.

Effect of ß3-adrenergic receptor on atrial L-type Ca(2+) current in rats with chronic heart failure.

OBJECTIVES: To investigate the effect of selective ß3-adrenoreceptor agonist BRL-37344 on L-type Ca(2+) current (Ica,L) and mRNA expression of L-type Ca(2+) channel α2δ-2 (Cacna2d2) in rats with chronic heart failure (CHF). METHODS: Twenty-four male Wistar rats were divided into normal control (n=6) and CHF group (n=18), which were further divided into CHF control and BRL group (0.4nmol/kg, IV, twice weekly for four weeks). Echocardiography was performed to assess the structure and function of the left atrium (LA). RESULTS: The LA in the BRL group (4.4 ± 0.2mm) was larger than in the normal control (3.5 ± 0.3mm, P<0.01) or CHF control (4.0 ± 0.2mm, P<0.05) group. The LA ejection fraction in the BRL group (36.2 ± 4.2%) was lower than in the normal control (58.0 ± 3.1%, P<0.01) or CHF control group (42.3 ± 4.8%, P<0.05). There was no difference in Ica,L density between the BRL group and CHF control group (8.3 ± 1.7 vs. 8.2 ± 2.6 pA/pF, P>0.05), which was higher than in the normal control group (6.0 ± 1.8 pA/pF, P<0.01). There was no difference in the mRNA expression of α2δ-2 (Cacna2d2) between the BRL group and CHF control group (0.264 ± 0.005 vs. 0.243 ± 0.017, P>0.05), which was also higher than in the normal control group (0.137 ± 0.013, P<0.01). CONCLUSION: ß3-Adrenoreceptor stimulation with BRL-37344 was associated with an increase in LA diameter and a decrease in LA function in chronic heart failure. These structural and function changes were not related to Ica,L or L-type Ca(2+) channel α2δ-2 (Cacna2d2) subunit in the LA myocytes.

Associations of MMP1, 3, 9 and TIMP3 genes polymorphism with isolated systolic hypertension in Chinese Han population.

BACKGROUND AND AIMS: Large artery stiffness and endothelial dysfunction are the predominant characteristic of isolated systolic hypertension. Recently studies have revealed MMP1, 3, 9 and TIMP3 Genes polymorphism were associated with arterial stiffness, but the relationship with isolated systolic hypertension were not further studied. This study was to investigate the associations of MMP1,3,9 and TIMP3 Genes polymorphism with isolated systolic hypertension. METHODS: We identified the genotype of the genes in 503 patients with isolated systolic hypertension, 481 essential hypertension patients with elevated diastolic blood pressure and 244 age-matched normotensive controls for 5 SNPs and detected the brachial-ankle pulse wave velocity, flow-mediated dilatation, endothelin-1 and nitric oxide among the participants. RESULTS: Multinomial logistic analyses showed that the 5A allele of rs3025058(5A/6A) in MMP3 and the T allele of rs3918242(C-1562T) in MMP9 were significantly associated with isolated systolic hypertension after adjusted by age, triglyceride, low-density lipoprotein (P<0.001, Pcorr<0.003; P=0.009, Pcorr=0.027). The 5A/G/C and 6A/A/T haplotypes were significantly associated with isolated systolic hypertension (Permutation p=0.0258; Permutation p=0.000002). In addition, the brachial-ankle pulse wave velocity of different genotypes for the 5A/6A and C-1562T polymorphisms was significantly highest in 5A or T homozygotes (P<0.01), however, the flow-mediated dilatation and nitric oxide were markedly lowest in 5A or T homozygotes (P<0.01). CONCLUSION: MMP3 and MMP9 genes variant seem to contribute to the development of isolated systolic hypertension by affecting arterial stiffness and endothelial function.

[Radiofrequency ablation for verapamil-sensitive ventricular tachycardia].

OBJECTIVE: To assess the efficacy and safety of radiofrequency catheter ablation for verapamil-sensitive ventricular tachycardia (VT). METHODS: A total of 18 patients with a diagnosis of verapamil-sensitive VT were enrolled in this study. Radiofrequency catheter ablation was administered after underwent examinations on admission to rule out structural heart disease. the ablation catheter was placed around the left posterior intermediate septum and left anteroseptal in the left ventricular to searching for the Purkinje potential (P potential). When the Purkinje potential preceded the surface QRS by ≥ 20 ms, it was considered as an ideal target for ablation. Ablation at 25 - 35 W, 60°C was often carried out at the point where the Purkinje potential was earliest. After ablation, perform programmed stimulation to measured the effects. The patients received routine postoperative treatment and care. And the follow-up period was 3 - 6 months after discharge. RESULTS: 17 patients diagnosed as ventricular raise from left posterior fascicle and 1 patient raise from left anterior fascicle were got to the radiofrequency end point and failed to elicit ventricular tachycardia again. In this patients, the Purkinje potential advanced to the starting point of QRS 20 ms were recognized as ideal point of radiofrequency. The length as the Purkinje potential advanced to the starting point of QRS are (24.0 ± 3.5) ms. the more length, the less times of radiofrequency. No postoperative complications were noted except for 2 patients who had mild hematoma at the site of puncture. During the follow-up period, 2 patients were found to have relapsed (recurrence rate = 11.1%) and showed transient resistance to verapamil. The remaining patients had no previous history of tachycardia. CONCLUSION: With a low recurrence rate, radiofrequency ablation is a safe and efficacious cure for verapamil-sensitive VT. Despite some efficacies in the treatment of VT.

[Value of Doppler echocardiography derived myocardial energy expenditure measurements in chronic heart failure patients].

OBJECTIVE: To evaluate the relationship between myocardial energy expenditure (MEE) level and cardiac function in chronic heart failure (CHF) patients. METHODS: A total of 99 CHF patients were divided into 3 groups according to the LVEF (HFNEF > or = 50%, n = 37; HFREF1 35.1% - 49.9%, n = 30; HFREF2 < or = 35%, n = 32) or the New York Heart Association (NYHA II, n = 26; III, n = 42; IV, n = 31) criteria. Thirty patients with cardiovascular disease and without CHF served as controls. Routine examinations including serum CRP (ELISA) and plasma NT-proBNP (chemiluminescence sandwich ELISA) were made on the next morning after admission; echocardiography was performed on the third day after admission. LVMW, LVMWI, RWT, LVIDd, LA, LV, LVEF, LVFS, E/A, EDT, IVRT, Tei index and MEE were measured or calculated. RESULTS: MEE was significantly higher in HFREF patients than in controls (P < 0.01) and similar between HFNEF patients and controls (P > 0.05). MEE increased in proportion to decrease of LVEF and increase of NYHA grades in CHF patients (all P < 0.05). Bivariate analysis confirmed that MEE was significant correlated with LVMW, LVMWI, RWT, LVIDd, LA, LV, LVEF (r = -0.540, P < 0.01), LVFS (r = -0.454, P < 0.01), E/A, EDT, IVRT, Tei index, NYHA grades, CRP and NT-proBNP. CONCLUSION: MEE derived from standard echocardiographic measurements is an effective indicator for myocardial bioenergetics and significantly correlated with cardiac function in CHF patients, especially in CHF patients with reduced LVEF.

[Early repolarization syndrome and recurrent syncope in two Chinese pedigrees].

OBJECTIVE: to investigate the clinical characteristics in two families with early repolarization syndrome (ERS) and recurrent syncope. METHOD: all family members including the probands were screened with routine clinical examination, electrocardiography, echocardiography, Holter recording, chest x-ray, head-up tilt test and blood biochemistry. RESULTS: there was no clinical evidence of organic heart disease in all members from the two families. Proband 1 showed recurrent syncope, ERS and repeated torsade de pointes ventricular tachycardia and ventricular fibrillation were documented with resting ECG. ERS was detected in one brother, one nephew and one son from him and all were free of cardiac events including syncope, cardiac arrest and sudden cardiac death. Proband 2 showed recurrent syncope, ERS and ST segment arched upward elevation in V(1)-V(3) were documented by ECG. His father suffered sudden cardiac death at the age of 65 and asymptomatic ERS was detected in one of his nephew. CONCLUSIONS: ERS is not always linked with benign clinical course and can sometimes lead to repeated syncope, torsade de pointes ventricular tachycardia and ventricular fibrillation. Pedigree research is of importance for ERS.

[Effects of a new houttuyfonate derivative on proliferation of NIH3T3 cell and expression of syndecan-4 induced by tumor necrosis factor alpha].

OBJECTIVE: To investigate the effect of a new houttuyfonate derivative (NHD) on proliferation of NIH3T3 cell and expression of Syndecan-4 induced by TNF-alpha in vitro. METHODS: NIH3T3 cells were cultured and exposed to TNF-alpha or NHD respectively, and then cotreated with TNF-alpha and NHD. All the groups were cultured for 24 hour in vitro, in addition to the untreated control group established for comparison. The ratio of proliferation of NIH3T3 cell was determined by non-radioactive MTS/PMS assay and the expression of Syndecan-4 was evaluated by western blot using anti-Syndecan-4 antibody. RESULTS: Statistical analysis showed that, compared with the control group, NHD had no effect on VSMCs growth, but significantly inhibited NIH3T3 cell proliferation while induced by TNF-alpha. It also showed that compared with control group, NHD had no effect on the expression of Syndecan-4, but significantly inhibited its expression while induced by TNF-alpha (P < 0.05). CONCLUSIONS: NHD can inhibit the proliferation of NIH3T3 cell and the expression of syndecan-4 protein induced by TNF-alpha in vitro.

Safe trajectory for an occipital condyle screw: A computer simulation study.

OBJECTIVE: The purpose of this study was to evaluate the feasibility of posterior occipital condyle screw (OCS) placement analysis of the safe trajectory area for screw insertion. METHODS: Computed tomographic angiography scans of patients (46 males and 27 females) with normal occipitocervical structures were obtained consecutively. Vertebral artery (VA)-occiput distance <4.0 mm was defined as "unfeasible" for OCS fixation, and occipital-atlas angulation was measured to assess the feasibility of screw placement. Next, the placement of 3.5 mm diameter OCS was simulated, the probability of breach of structures surrounding occipital condyles was calculated, and placement parameters were analyzed. RESULTS: OCS placement was feasible in 91.1% (133/146) of occipital condyles, and the feasible probability also presented a significant sex-related difference: The probability was higher for males than for females (95.7% vs. 83.3%, p < 0.05). The incidence of anatomical structures injured under screw placement limitation was 18.8% (VA), 81.2% (hypoglossal canal), 59.4% (occipital-atlas joint), and 40.6% (occiput bone surface). There were no significant differences between the left and right condyles in relation to the measured parameters (p > 0.05). The screw range of motion was significantly smaller in females than in males (p < 0.05). The feasibility of OCS placement and OCS range of motion were significantly greater in the kyphosis group (>5°) than in the other two groups (p < 0.05). CONCLUSION: OCS placement is a feasible technique for occipital-cervical fusion. The male group and occipitocervical region kyphosis group had a wider available space for OCS placement. Tangent angulation may be useful for the accurate and safe placement of an OCS.

Modified Broström Repair With and Without Augmentation Using Suture Tape for Chronic Lateral Ankle Instability.

OBJECTIVE: To compare the clinical and radiological outcome between the modified Broström repair with augmentation using suture tape (MBA) and the modified Broström repair (MB) for patients with chronic lateral ankle instability. METHODS: A retrospective study was performed in Ningbo No. 6 Hospital. The study included 53 patients who underwent surgical treatment from March 2014 to July 2016 and were followed for 2 years. A total of 25 patients underwent modified Broström repair with augmentation using suture tape, and 28 patients were treated with modified Broström repair. Patients were evaluated using the American Orthopedic Foot and Ankle Scale (AOFAS) hindfoot scale, the Foot and Ankle Ability Measure (FAAM) score, range of motion (ROM), and the visual analogue scale (VAS). The talar tilt angle (TTA) and anterior talar translation (ATT) were used to evaluate the mechanical stability. All radiological outcomes were measured by two orthopaedic surgeons, with the measurements repeated 3 days later. RESULTS: The mean age of the patients was 26.6 ± 17.8 years in the MBA group and 28.1 ± 19.4 years in the MB group, and no statistical difference in preoperative data was found between two groups. There were significant differences before and after the operation within the groups. Both groups achieved satisfactory outcomes, and significant improvements (VAS, FAAM, AOFAS, TTA, and ATT) were observed between the 1-year follow-up and final follow-up (P < 0.05). The MBA group showed significant improvement in the FAAM Sport (87.1 ± 5.4 vs 78.2 ± 12.0, P = 0.001) and total scores (93.1 ± 2.3 vs 90.5 ± 5.1, P = 0.027) at the final follow-up compared with the MB group, and for the other outcomes, there were no significant differences between the two groups. CONCLUSION: The modified Broström repair with augmentation using suture tap for chronic lateral ankle instability achieves a better outcome; however, further research is necessary.

[Effects of flavone from leaves of Diospyros kaki on expression of apoptosis signal-regulating kinase 1 and rat vascular smooth muscle cells proliferation by tumor necrosis factor alpha in vitro].

OBJECTIVE: To observe the effects of flavone from leaves of Diospyros kaki on expression of apoptosis signal-regulating kinase 1 (ASK1) and rat vascular smooth muscle cells (VSMCs) proliferation by tumor necrosis factor alpha in vitro. METHODS: Rat aortic VSMCs were cultured in vitro and treated with tumor necrosis factor alpha (TNF-alpha) and flavone from leaves of Diospyros kaki, respectively, and were observed in comparison with the control group. The ratio of cell proliferation was determined by non-radioactive MTS/PES as-say. The expression of ASK1 protein was evaluated by the immunoblotting technique using anti-ASKL antibody. RESULTS: The ratio of cell proliferation was 0.817 +/- 0.074 in the control group, and was 1.865 +/- 0.093 in TNF-alpha20 ng/ml group. It was shown that TNF-alpha significantly induced rat VSMCs proliferation (P < 0.05). The ratio of cell proliferatioh was 0.905 +/- 0.044 in flavone from leaves of Diospyros kaki group corresponding to concentration of 50 microg/ml. It was shown that flavone from leaves of Diospyros kaki alone had no effect on rat VSMCs proliferation (p > 0.05). With TNF-alpha stimulation, flavone from leaves of Diospyros kaki significantly inhibited rat expression of ASK1 protein enhanced by TNF-alpha was significantly inhibited rat-VSMNCs proliferation (1.247 +/- 0.061 vs. 1.865 +/- 0.093, p < 0.05). The expression of ASK1 protein enhanced by TNF-alpha was significantly inhibited by flavone from leaves of Diospyros kaki in VSMCs. CONCLUSION: Flavone from leaves of Diospyros kaki can significantly inhibit expression of ASK1 protein stimulated by TNF-alpha of rat VSMcs in vitro.

Characterization of the Myocarditis during the worst outbreak of dengue infection in China.

Myocarditis is a common complication of severe dengue infection. However, data about prevalence and characterization of myocarditis in dengue are still lacking. In 2014, the worst outbreak of dengue in the last two decades in China occurred. In this study, we described the clinical and laboratory diagnostic features of dengue with myocarditis. Totally, 1782 diagnosed dengue patients were admitted from August to October, 2014, all of whom were subjected to electrocardiogram, ultrasound cardiogram, and cardiac enzyme test. About 201 cases of dengue patients were diagnosed with myocarditis and the prevalence of myocarditis in hospitalized dengue was 11.28%. The prevalence of myocarditis in nonsevere dengue with warning signs and severe dengue [NSD(WS+)/SD] and nonsevere dengue without warning signs [NSD(WS-)] was 46.66% and 9.72%, respectively. The NSD(WS+)/SD patients with myocarditis presented with higher incidence of cardiac symptoms, supraventricular tachycardia (14.29% vs. 0%, P < 0.001), atrial fibrillation (25.71% vs. 10.24%, P = 0.019) and heart failure compared with NSD (WS-) patients with myocarditis. About 150 cases of dengue patients without myocarditis in the same period of time in department of Cardiology were recruited as control group. The proportion of NSD(WS+)/SD in dengue patients with and without myocarditis was 17.41% and 2.53%, respectively. Dengue patients with myocarditis experienced longer hospital stay than those without myocarditis (7.17 ±â€Š4.64 vs. 5.98 ±â€Š2.69, P = 0.008). There was no difference between patients with and without myocarditis in the proportion of symptoms, auxiliary methods abnormality, arrhythmia, and heart failure on the discharge day. Our study demonstrates the prevalence of myocarditis in worst outbreak of dengue in China was 11.28% and the incidence of myocarditis increased with the severity of dengue. The NSD(WS+)/SD patients with myocarditis presented with higher incidence of cardiac complication compared with NSD (WS-) patients with myocarditis. The prognosis of dengue patients with and without myocarditis had no significant difference even if myocarditis patients experienced longer hospital stay.

[Transient cytosolic free calcium changes in cultured neonatal rat cardiac myocytes in response to advanced glycation end-product treatment].

OBJECTIVE: To investigate the effects of advanced glycation end-products (AGEs) on transient cytosolic free calcium in neonatal rat cardiac myocytes (CMs) cultured in vitro. METHODS: CMs cultured for 3 to 5 days in vitro were incubated with Ca(2+)-sensitive fluorescent indicator Fluo-3AM with light screening at 37 degrees celsius; with 5% CO(2) for 60 min. Changes of the fluorescence signal of free calcium caused by AGEs were measured under laser scanning confocal microscope (LSCM). RESULTS: Compared with the control cells, AGEs caused an increase in the concentration of cytosolic free calcium in a dose-dependent manner. CONCLUSION: AGEs may impair neonatal rat CMs by altering cytosolic free calcium concentration.

[Effects of captopril and losartan on expression of kidney aquaporin-2 mRNA and urine aquaporin-2 excretion in rats].

OBJECTIVE: To investigate effects of captopril and losartan on the expression of kidney aquaporin-2 (AQP2) mRNA and the excretion of urine AQP2 in rats. METHODS: Thirty healthy rats were randomized into 3 groups, namely the control group, captopril group and losartan group, respectively. Blood and urine samples were collected from the rats for detecting serum Na(+), urine volume and urine osmolality in the course of medication. Urine AQP2 concentration was measured by enzyme-linked immunosorbent assay (ELISA). Semi-quantitative RT-PCR was performed for measurement of kidney inner medullary AQP2 and vasopressin V(2) receptor mRNA. RESULTS: Urine volume was increased in rats of captopril and losartan groups as compared with that of the control group. However, urine osmolality was lower in captopril group than in the other two groups (P<0.05). RT-PCR revealed decreased quantity of the inner medullary AQP2 mRNA of the captopril group than that of the other two groups, but the quantity of V(2) receptor mRNA did not differ significantly between the 3 groups. Urine AQP2 concentration was significantly higher in captopril group than in the control (P<0.05) and losartan groups (P0<0.01). CONCLUSION: Captopril can reduce the expression of the kidney inner medullary AQP2 mRNA and accelerate the excretion of the urine AQP2 in normal rats.

[Quantitative evaluation of canine renal blood flow with contrast-enhanced ultrasound].

OBJECTIVE: To evaluate the accuracy of contrast-enhanced ultrasound (CEU) in renal blood flow quantification. METHODS: Regional renal perfusion was quantified with CEU in 10 dogs at the baseline level and after treatment with 3 doses of dopamine (3, 8 and 16 mg.kg(-1).min(-1)), and renal arterial flow (RAF) was measured with ultrasonic flow probes deployed directly on the renal artery simultaneously. Normalized RAF was calculated as RAF divided by renal weight (ml.min(-1).g(-1)). RESULTS: Compared with the baseline level, a progressive increase in RAF was induced by dopamine treatment at the doses of 3 and 8 mg.kg(-1).min(-1) (P<0.05), but at a higher dose of 16 mg.kg(-1).min(-1), the increment in RAF was reduced in comparison with that with the two lower doses (P<0.05). The same changes in cortical nutrient blood flow derived from CEU were observed. Significant positive correlation was found between normalized RAF and CEU-derived cortical nutrient blood flow (y=39.8x + 44.3, r=0.88, P<0.001). CONCLUSION: CEU can be used to accurately quantify renal blood flow in dogs.

[Effects of a novel recombinant polypeptide from the sea anemone Anthopleura sp. on left ventricular function in dogs with acute cardiac insufficiency].

OBJECTIVE: To observe the effects of recombinant hk2a, a novel neurotoxin from the sea anemone Anthopleura sp., on left ventricular function of dogs with acute cardiac insufficiency. METHODS: Canine models of acute cardiac insufficiency were established by rapid ventricular pacing, in which the left ventricular ejection fraction (LVEF) was measured by Acuson ultrasound systems (Sequoia 512) at 0, 5, 15, 30 and 60 min, respectively, after intravenous injection of 30 microg/kg recombinant hk2a. The response of the canine models to hk2a treatments was observed in comparison with that of the dogs treated with Cedilanid (as positive control) and saline (as negative control). RESULTS: Intravenous injection of recombinant hk2a caused an immediate and significant increase in LVEF in the canine models of acute cardiac insufficiency (P<0.05), and the effect maintained for more than 30 min without significant effect on heart rate. Recombinant hk2a possessed such merits as quicker onset and greater potency in comparison with Cedilanid. CONCLUSION: Recombinant hk2a may significantly increase LVEF of the dogs with acute cardiac insufficiency.

[Regulation of cyclin-dependent kinase inhibitors by mitogen-activated protein kinase in angiotensin II-stimulated vascular smooth muscle cell hypertrophy].

OBJECTIVE: To investigate the role of mitogen-activated protein kinase (MAPK) in the regulation of cyclin-dependent kinase inhibitors (CDKI) in the process of vascular smooth muscle cell (VSMC) hypertrophy induced by angiotensin II stimulation. METHODS: The medial layer of male SD rat aorta was isolated for VSMC culture. After cultured in serum-free medium to arrest the cell growth, VSMCs were stimulated with angiotensin II (1x10(-6) mol/L) or/and phorbol myristate acetate (PMA, 20 nmol/L), with the cells cultured in serum-free medium serving as control. MAPK activity of the cells was assayed 90 min after stimulation with immunoprecipitation test, and the expression levels of CDKI p27, p57 and p21 were determined by Western blotting 6 and 24 h after stimulation respectively. RESULTS: Compared with the control level, MAPK activity of the VSMCs was up-regulated by 238% by treatment with angiotensin II alone which, however, did not inhibit p27 expression or induce VSMC proliferation. Costimulation with angiotensin II and PMA slightly inhibited p27 expression but VSMC proliferation was still not observed. CONCLUSION: MAPK pathway is an important channel for extracellular proliferative and hypertrophic signal transduction into the nucleus of VSMCs.

[Effects of advanced glycation end-products on cell cycle distribution and apoptosis in neonatal rat cardiac myocytes].

OBJECTIVE: To investigate the effects of advanced glycation end-products (AGEs) on cell cycle distribution and apoptosis in neonatal rat cardiac myocytes (CMs) cultured in vitro. METHODS: CMs already cultured for 3 to 5 d in vitro were continuously cultured with DMEM supplemented with 1% or 10% fetal bovine serum for 24 h, prior to exposure to AGE-modified human serum albumin (AGE-HSA, at 50 and 100 microg/ml) for 12, 24 and 48 h. Cells cultured in the same manner but without AGE-HSA treatment served as the control group. All cells were collected and analyzed by flow cytometry for cell cycle distribution and cell apoptosis, and the number of apoptotic body/nucleus of CMs was determined by in situ cell death detection kit (fluorescein). RESULTS: AGEs had no obvious effects on cell cycle distribution in CMs, but could increase the number of apoptotic body/nucleus of CMs in a time-dependent manner to up to 0.55 and 1.23 times at 24 and 48 h respectively, as compared with the number at 12 h in control cells. AGEs at 50 and 100 microg/ml increased the number of apoptotic body/nucleus of CMs to various degrees at different time points: 0.74 and 1.21 times respectively at 12 h; 1.15 and 1.78 times at 24 h; 0.83 and 1.19 times at 48 h. The average number of apoptotic body/nucleus of the cells treated with 100 microg/ml AGEs at 12, 24, 48 h were 0.27, 0.29, 0.20 times respectively that of the cells with 50 microg/ml AGEs treatment. CONCLUSIONS: AGEs do not affect the distribution of cell cycle but can impair neonatal rat CMs by increasing their apoptosis rate.

Recombinant Lapemis hardwickii phospholipase A2 inhibits rat vascular smooth muscle cell proliferation stimulated by advanced glycation end products.

OBJECTIVE: To observe the effects of recombinant Lapemis hardwickii phospholipase A(2) (rPLA(2)) on vascular smooth muscle cell (VSMC) proliferation stimulated by advanced glycation end products (AGEs). METHODS: Rat aortic VSMCs were cultured in vitro and stimulated with AGEs of different concentrations prior to co-treatment with rPLA(2) and AGEs. The response of the VSMCs to these treatments was observed in comparison with that of the control group. Non-radioactive MTS/PES assay was adopted for the quantification of the cell proliferation ratio. RESULTS: Compared with the control group, AGEs significantly stimulated VSMCs proliferation (P < 0.05), but even with AGEs stimulation, rPLA(2) inhibited the growth of VSMCs (0.753+/-0.098 vs 1.100+/-0.226, P < 0.05). CONCLUSION: rPLA(2) can significantly inhibit the proliferation of VSMCs stimulated by AGEs.