Molecular Mechanism and Potential Clinical Value of Lysophosphatidic Acid in Vascular Endothelial Cells / 中国生物化学与分子生物学报

The vascular system constitutes the largest surface of the human body. Vascular endothelial cells are a layer of flat epithelial cells covering the inner wall of blood vessels and have a variety of biolog-

Influence of electroacupuncture on ghrelin and the phosphoinositide 3-kinase/protein kinase B/endothelial nitric oxide synthase signaling pathway in spontaneously hypertensive rats / 中西医结合学报

OBJECTIVE@#To investigate the influence of electroacupuncture (EA) on ghrelin and the phosphoinositide 3-kinase/protein kinase B/endothelial nitric oxide synthase (PI3K/Akt/eNOS) signaling pathway in spontaneously hypertensive rats (SHRs).@*METHODS@#Eight Wistar-Kyoto rats were used as the healthy blood pressure (BP) control (normal group), and 32 SHRs were randomized into model group, EA group, EA plus ghrelin group (EA + G group), and EA plus PF04628935 group (a potent ghrelin receptor blocker; EA + P group) using a random number table. Rats in the normal group and model group did not receive treatment, but were immobilized for 20 min per day, 5 times a week, for 4 continuous weeks. SHRs in the EA group, EA + G group and EA + P group were immobilized and given EA treatment in 20 min sessions, 5 times per week, for 4 weeks. Additionally, 1 h before EA, SHRs in the EA + G group and EA + P group were intraperitoneally injected with ghrelin or PF04628935, respectively, for 4 weeks. The tail-cuff method was used to measure BP. After the 4-week intervention, the rats were sacrificed by cervical dislocation, and pathological morphology of the abdominal aorta was observed using hematoxylin-eosin (HE) staining. Enzyme-linked immunosorbent assay (ELISA) was used to detect the levels of ghrelin, nitric oxide (NO), endothelin-1 (ET-1) and thromboxane A2 (TXA2) in the serum. Isolated thoracic aortic ring experiment was performed to evaluate vasorelaxation. Western blot was used to measure the expression of PI3K, Akt, phosphorylated Akt (p-Akt) and eNOS proteins in the abdominal aorta. Further, quantitative real-time polymerase chain reaction (qRT-PCR) was conducted to measure the relative levels of mRNA expression for PI3K, Akt and eNOS in the abdominal aorta.@*RESULTS@#EA significantly reduced the systolic BP (SBP) and diastolic BP (DBP) (P < 0.05). HE staining showed that EA improved the morphology of the vascular endothelium to some extent. Results of ELISA indicated that higher concentrations of ghrelin and NO, and lower concentrations of ET-1 and TXA2 were presented in the EA group (P < 0.05). The isolated thoracic aortic ring experiment demonstrated that the vasodilation capacity of the thoracic aorta increased in the EA group. Results of Western blot and qRT-PCR showed that EA increased the abundance of PI3K, p-Akt/Akt and eNOS proteins, as well as expression levels of PI3K, Akt and eNOS mRNAs (P < 0.05). In the EA + G group, SBP and DBP decreased (P < 0.05), ghrelin concentrations increased (P < 0.05), and the concentrations of ET-1 and TXA2 decreased (P < 0.05), relative to the EA group. In addition, the levels of PI3K and eNOS proteins, the p-Akt/Akt ratio, and the expression of PI3K, Akt and eNOS mRNAs increased significantly in the EA + G group (P < 0.05), while PF04628935 reversed these effects.@*CONCLUSION@#EA effectively reduced BP and protected the vascular endothelium, and these effects may be linked to promoting the release of ghrelin and activation of the PI3K/Akt/eNOS signaling pathway.

Progress of prokineticin 2 in cardiovascular diseases / 中国药理学通报

Cardiovascular diseases are characterized by cardiac and vascular dysfunction. Prokineticin 2 ( PK2 ) is a newly found secretory peptide which plays a key role in the physiology homeostasis via prokineticin receptor 1 and 2 ( PKR1 and 2). Furthermore, PK2/PKR1 signaling pathway plays an important role in protecting cardiovascular diseases. Here we discuss the effect of PK2/PKR1 signaling in myocardial infarction, conges-tive heart failure and vascular endothelial dysfunction.

Effect of high glucose on endothelial function / 中国生化药物杂志

Objective To investigate effect of high glucose on the function of endothelial and the underlying mechanisms in human umbilical vascular endothelial cells (HUVECs).Methods The experiment was divided into 4 groups: normal group (NG), low dose group (LG), middle dose group (MG) and high dose group ( HG) .The concentration of glucose in the culture medium was 5.5, 10, 20, 30 mmol/L in the 4 groups, respectively.The HUVECs was cultured for 0, 24, 48 h.At different time point, the cell viability were measured by MTT.The secretary content of nitric oxide (NO) in the supernatant were detected using test kit.The extraction of protein were extracted for Western blot analysis to detect the expression of endothelial nitric oxide synthase (eNOS).ResuIts Compared with normal group at same time point (cultured for 24 h), the cell viability and the content of NO were significantly decreased in LG, MG(P<0.05).The expression of eNOS in HG were markedly reduced (P<0.01).Compared with normal group at same time point (cultured for 48 h), the cell viability decreased significantly in HG (P <0.05).The expression of eNOS were markedly decreased 11.91, 25.72 and 34.50% in LG, MG and HG, respectively.A rising trend of cell viability were found in NG, LG and MG, but a descending trend were found in HG within 48 h.ConcIusion The cell viability were significantly affected by high glucose.The endothelial dysfunction induced by high glucose may be associated with the reduction of eNOS and NO production.

Expression Profile of Neuro-Endocrine-Immune Network in Rats with Vascular Endothelial Dysfunction

This study was to determine the correlation between endothelial function and neuro-endocrine-immune (NEI) network through observing the changes of NEI network under the different endothelial dysfunction models. Three endothelial dysfunction models were established in male Wistar rats after exposure to homocysteine (Hcy), high fat diet (HFD) and Hcy+HFD. The results showed that there was endothelial dysfunction in all three models with varying degrees. However, the expression of NEI network was totally different. Interestingly, treatment with simvastatin was able to improve vascular endothelial function and restored the imbalance of the NEI network, observed in the Hcy+HFD group. The results indicated that NEI network may have a strong association with endothelial function, and this relationship can be used to distinguish different risk factors and evaluate drug effects.

Role of oxLDL/LOX-1 system and NF-κB pathway in early diabetic vascular endothelial dysfunction / 中华内分泌代谢杂志

Diabetic rat model was established by peritoneal injection of streptozocin.At the end of 2 weeks,oxidized low-density lipoprotein (oxLDL) level in diabetic rats was raised [ ( 2.87 ± 0.40 vs 2.27 ± 0.36 ) μg/dl,P＜0.05 ] and endothelium-dependent relaxation was sluggish compared with normal rats.At the end of 6 weeks,oxLDL level continued to increase [ 4.32 ±0.66 ) μg/dl,P＜0.01] and endothelium-dependent maximum relaxation ( Rmax ) was decreased obviously ( P ＜0.01 ).Meanwhile,the protein and mRNA expressions of lectin-like oxidized lowdensity lipoprotein receptor-1 ( LOX-1 ),NF-kB,and ICAM-1 on vessel wall of diabetic rats were higher than those in normal rats,and LOX-1 mRNA was positively correlated with the levels of oxLDL,NF-kB,and ICAM-1 mRNA,while negatively correlated with Rmax,indicating that OxLDL/LOX-1 system may cause early endothelial dysfunction in diabetes via activating NF-kB and up-regulating ICAM-1 expression.

Role of ADMA-DDAH axis in the vascular endothelial dysfunction induced by uric acid / 中华肾脏病杂志

Objective To observe the formation of asymmetric dimethylarginine (ADMA)and the expression of dimethylarginine dimethylaminohydrolase 2 (DDAH-2) of human umbilical vein endothelial cells (HUVECs) stimulated by uric acid (UA), and to explore the role of ADMADDAH axis in the vascular endothelial dysfunction induced by uric acid. Methods HUVECs were cultured in M199 medium supplemented with 10% FBS. Cells were exposed to different concentrations of UA (0, 60, 120 mg/L) for 6 h and 24 h. Under different concentrations and times, the level of ADMA in cell suspension was detected by high performance liquid chromatography (HPLC) technique; the gene and protein expressions of DDAH-2 were detected by RT-PCR and Western blotting; the fluorescence intensity of intracellular 2',7'-dichlorofluorescein (DCF) which represented the productions of ROS was detected by the flow cytometry (FCM). The activity of DDAH-2 in HUVCEs which were exposed to different concentrations of UA (0, 60, 120mg/L) or UA (120 mg/L) +NAC (10 mmol/L) for 24 h was estimated by directly measuring the amount of ADMA metabolized by the enzyme and the role of NAC in the activity was studied.Results The expression of ADMA induced by urid acid was dose-depent and higher at 24 h than that at 6 h in the same dosage (all P＜0.05). The dosage and stimulation time of UA did not have any influence on the expression of intracellular DDAH-2 (all P＞0.05). When HUVECs exposed to UA (120 mg/L) for 24 h, the production of intracellular ROS was significantly increased while the activity of DDAH-2 was decreasesd (all P＜0.05) as compared to 60 mg/L stimulation. This effect could be inhibited by the intervention of anti-oxidant NAC. Conclusions The high UA stimulation on HUVECs can increase the expression of intracellular ROS and inhibit the activity of DDAH-2 which increases the concentration of ADMA by decreasing the degradation of ADMA as well as the formation of NO. DDAH-ADMA axis may participate in the vascular endothelial dysfunction induced by UA.

Role of glucagon-like peptide-1 in vascular endothelial dysfunction.

The present study has been undertaken to investigate the effect of exendin-4 (a glucagon-like peptide-1 agonist) in diabetes mellitus (DM) and hyperhomocysteinemia (HHcy)-induced vascular endothelial dysfunction (VED). Streptozotocin (55 mg kg−1, iv, once) and methionine (1.7% w/w, po, 4 weeks) were administered to rats to produce DM (serum glucose >200 mg dl−1) and HHcy (serum homocysteine >10 μM) respectively. VED was assessed using isolated aortic ring preparation, microscopy of thoracic aorta, and serum nitrite/nitrate concentration. Serum TBARS concentration was estimated to assess oxidative stress. Atorvastatin has been employed as standard agent. Exendin-4 (1 μg kg−1, ip) and atorvastatin (30 mg kg−1, po) treatments significantly attenuated increase in serum glucose and homocysteine but their concentrations remained markedly higher than sham control value. Exendin-4 and atorvastatin treatments markedly prevented DM and HHcy-induced (i) attenuation of acetylcholine-induced endothelium-dependent relaxation, (ii) impairment of vascular endothelial lining, (iii) decrease in serum nitrite/nitrate concentration, and (iv) increase in serum TBARS. However, this ameliorative effect of exendin-4 has been prevented by L-NAME (25 mg kg-1, ip), an inhibitor of NOS. It may be concluded that exendin-4 may activate eNOS due to activation of GLP-1 and consequently reduce oxidative stress to improve vascular endothelial dysfunction.

Reduction in Visceral Adiposity is Highly Related to Improvement in Vascular Endothelial Dysfunction among Obese Women: An Assessment of Endothelial Function by Radial Artery Pulse Wave Analysis

Because obesity is frequently complicated by other cardiovascular risk factors, the impact of a reduction in visceral adiposity on vascular endothelial dysfunction (VED) in obese patients is difficult to determine. In the present study, we evaluated the impact of a reduction in visceral adiposity on VED in obese women. Thirty-six premenopausal obese women (BMI > or = 25 kg/m2) without complications were enrolled in the study. VED was evaluated by determining the augmentation index (AIx) from radial artery pulse waves obtained by applanation tonometry. Changes in AIx in response to nitroglycerin- induced endothelium-independent vasodilatation (delta AIx-NTG) and in response to salbutamol administration (delta AIx-Salb) were determined before and after weight reduction. After a 12-week weight reduction program, the average weight loss was 7.96 +/- 3.47 kg, with losses of 21.88 +/- 20.39 cm2 in visceral fat areas (p 0.1) and an improvement in endothelial-dependent vasodilation following weight reduction (delta AIx-Salb: 10.03 +/- 6.49% before weight reduction vs. 19.33 +/- 9.28% after reduction, p < 0.001). A reduction in visceral adipose tissue was found to be most significantly related to an increase in delta AIx-Salb (beta=-0.57, p < 0.001). A reduction in visceral adiposity was significantly related to an improvement in VED. This finding suggests that reduction of visceral adiposity may be as important as the control of other major risk factors in the prevention of atherosclerosis in obese women.

The Predicting Factor of Vascular Endothelial Dysfunction in Healthy Premenopausal Obese Women

BACKGROUND: Vascular endothelial dysfunction (VED) plays a pivotal role in the pathogenesis of atherosclerosis and is associated with insulin resistance and with visceral obesity. Therefore, in this study the predicting factor of vascular endothelial dysfunction was investigated in healthy premenopausal obese women by pulse-wave analysis (PWA) combined with provocative pharmacological testing. METHODS: Thirty three obese women (BMI> or =25), aged 20~45 y and 25 age-matched control subjects (BMI; 18.5~22.9) were examined. All women were sedentary (<1 hr/wk of physical activity), non-smoker and were excluded if they had type 2 diabetes melitus, hypertension, hyperlipidemia, cardiovascular disease, or acute inflammatory disease and were studied in folicullar phase of the cycle, within the first week after cessation of menstrual bleeding. They underwent determination of anthropometric measurements, metabolic variables, adipose tissue regional distribution, and endothelial function by performing pulse-wave analysis (PWA) combined with provocative pharmacological testing. RESULTS: Augmentation Index (AIx) fell significantly after the administration of salbutamol, which causes endothelium-dependent vasodilatation, but response was significantly reduced in obese women compared with controls (10.28 6.72% vs 17.2 6.84%, P=0.0003). The change in after Nitroglycerin, which causes endothelium-independent vasodilatation, did not differ significantly (30.86 9.67% vs 30.6 10.11%, P=0.9172). In our obese subjects, visceral adipose tissue area was independently a significant predictor of vascular endothelial dysfunction (beta= 0.1381, P=0.0038, Adj-R2=0.348). CONCLUSION: Increased abdominal adiposity is a powerful independent predictor of VED in obese healthy women. Future studies of vascular endothelial function should account for the independent effects of abdominal fat.

Relationship between plasma osteoprotegerin and endothelium-dependent arterial dilation in type 2 diabetic patients / 中华内分泌代谢杂志

Objective To research the relationship between plasma osteoprotegerin (OPG) level and endothelium-dependent arterial dilation (EDAD) in type 2 diabetic patients.Methods The subjects included 40 newly diagnosed type 2 diabetic patients and 46 healthy subjects.Insulin therapy were then given to all diabetic patients for 6 months.Plasma OPG was measured by a sandwich ELISA method,and brachial artery diameter was determined by high resolution ultrasound at rest after reactive hyperemia and after sublingual glyceryl trinitrate (GTN).Results Plasma OPG level in diabetic patients before treatment was (3.44?0.52) ng/L,which was significantly higher than that in control (2.38?0.25 ) ng/L (P