Phosphorylated PKM2 regulates endothelium-dependent vasodilation in diabetes / 中南大学学报(医学版)

OBJECTIVES@#Endothelium-dependent vasodilation dysfunction is the pathological basis of diabetic macroangiopathy. The utilization and adaptation of endothelial cells to high glucose determine the functional status of endothelial cells. Glycolysis pathway is the major energy source for endothelial cells. Abnormal glycolysis plays an important role in endothelium-dependent vasodilation dysfunction induced by high glucose. Pyruvate kinase isozyme type M2 (PKM2) is one of key enzymes in glycolysis pathway, phosphorylation of PKM2 can reduce the activity of pyruvate kinase and affect the glycolysis process of glucose. TEPP-46 can stabilize PKM2 in its tetramer form, reducing its dimer formation and phosphorylation. Using TEPP-46 as a tool drug to inhibit PKM2 phosphorylation, this study aims to explore the impact and potential mechanism of phosphorylated PKM2 (p-PKM2) on endothelial dependent vasodilation function in high glucose, and to provide a theoretical basis for finding new intervention targets for diabetic macroangiopathy.@*METHODS@#The mice were divided into 3 groups: a wild-type (WT) group (a control group, C57BL/6 mice) and a db/db group (a diabetic group, db/db mice), which were treated with the sodium carboxymethyl cellulose solution (solvent) by gavage once a day, and a TEPP-46 group (a treatment group, db/db mice+TEPP-46), which was gavaged with TEPP-46 (30 mg/kg) and sodium carboxymethyl cellulose solution once a day. After 12 weeks of treatment, the levels of p-PKM2 and PKM2 protein in thoracic aortas, plasma nitric oxide (NO) level and endothelium-dependent vasodilation function of thoracic aortas were detected. High glucose (30 mmol/L) with or without TEPP-46 (10 μmol/L), mannitol incubating human umbilical vein endothelial cells (HUVECs) for 72 hours, respectively. The level of NO in supernatant, the content of NO in cells, and the levels of p-PKM2 and PKM2 protein were detected. Finally, the effect of TEPP-46 on endothelial nitric oxide synthase (eNOS) phosphorylation was detected at the cellular and animal levels.@*RESULTS@#Compared with the control group, the levels of p-PKM2 in thoracic aortas of the diabetic group increased (P<0.05). The responsiveness of thoracic aortas in the diabetic group to acetylcholine (ACh) was 47% lower than that in the control group (P<0.05), and that in TEPP-46 treatment group was 28% higher than that in the diabetic group (P<0.05), while there was no statistically significant difference in the responsiveness of thoracic aortas to sodium nitroprusside (SNP). Compared with the control group, the plasma NO level of mice decreased in the diabetic group, while compared with the diabetic group, the phosphorylation of PKM2 in thoracic aortas decreased and the plasma NO level increased in the TEPP-46 group (both P<0.05). High glucose instead of mannitol induced the increase of PKM2 phosphorylation in HUVECs and reduced the level of NO in supernatant (both P<0.05). HUVECs incubated with TEPP-46 and high glucose reversed the reduction of NO production and secretion induced by high glucose while inhibiting PKM2 phosphorylation (both P<0.05). At the cellular and animal levels, TEPP-46 reversed the decrease of eNOS (ser1177) phosphorylation induced by high glucose (both P<0.05).@*CONCLUSIONS@#p-PKM2 may be involved in the process of endothelium-dependent vasodilation dysfunction in Type 2 diabetes by inhibiting p-eNOS (ser1177)/NO pathway.

Application of fingertip photoplethysmogram assessment of endothelial function in screening coronary heart disease patients / 吉林大学学报(医学版)

Objective:To investigate the application of photoplethysmogram in analyzing the fingertip pulse amplitude volume (PAV)to evaluate the endothelial function in diagnosing coronary heart disease,and to clarify its relationship with the risk factors of cardiovascular diseases.Methods:Total 409 patients with chest pain accepted coronary angiography (CAG)were selected and diveded into positive group (CAG+)(n=288)and negative group (CAG-) (n = 121)according to angiographic results.Fingertip photoplethysmogram was used to analyze the fingertip PAV by the way of applying endothelial function diagnostic after reactive ischemia,and the relationship between the PAV value and the risk factors of coronary heart diseases was analyzed,and the critical reference value of prediction index of coronary heart disease was determined.The risk factors such as age,gender,serum total cholesterol (TC ), low density lipoprotein (LDL ), high density lipoprotein (HDL ), non-HDL, serum triglyceride (TG),hypertension,diabetes,smoking,family history of coronary heart disease,body mass index (BMI)of the subjects in various groups were analyzed,and the relationship between the risk factors of coronary heart disease and PAV was analyzed by Logistic regression analysis.Results:The PAV of patients in CAG+group was significantly lower than that in CAG-group (P <0.01).The peak point of PAV was<1.37,if PAV<1.37 was used to predict the coronary heart disease,the predictive sensitivity,the specificity,the positive prediction and the negative prediction were 74.65%,44.63%, 76.24%, and 42.52%.The Logistic regression analysis showed that PAV was negatively associated with hypertension,smoking history,TG (OR= 1.476,OR=2.002, OR = 1.844;P < 0.01 ). Conclusion: PAV is associated with coronary heart disease and its risk factors (hypertension,smoking history,TG),and PAV=1.37 can be used as the peak point to predict the coronary heart disease.

Effect of different doses of rosuvastatin on brachial artery endothelium-dependent vasodilation and carotid intima-media thickness in patients with coronary heart disease / 中国生化药物杂志

Objective To investigate effect of different doses of rosuvastatin on brachial artery endothelium-dependent vasodilation and carotid intima-media thickness in patients with coronary heart disease.Methods 92 patients with coronary heart disease in our hospital were admitted and divided into four groups according to randomly digital method, including 23 cases in control group were treated with lipid nitrate, antiplatelet aggregation, anticoagulant, lowering blood sugar, blood pressure control and other of conventional therapy;23 cases in group A, on the basis of conventional therapy, were treated with rosuvastatin 5 mg/d, orally, once daily;23 cases in group B were treated with rosuvastatin 10 mg/d, orally, once daily based on the conventional therapy;23 cases in group C were treated with rosuvastatin 20 mg/d, orally, once daily based on conventional treatment, each group was treated for 8 weeks.Brachial artery endothelium-dependent vasodilation (FMD) and carotid intima-media thickness (IMT) of patients before and after treatment were collected by color ultrasonic doppler, while observed lipid levels changes of 4 groups.Results Control group was treated for eight weeks, FMD, ITM, blood lipid levels and each index values were not significantly changed, the difference was not statistically significant;After treatment, total cholesterol ( TC) , low-density lipoprotein cholesterol C ( LDL-C) of A, B, C groups were significantly better than that before treatment, the difference was statistically significant (P<0.05), and decrease amplitude with dose of rosuvastatin increased became grearer, but the total cholesterol (TC), high density lipoprotein cholesterol C( HDL-C) there was no significant difference compared with before treatment; Compared with before treatment, ITM of A, B, C groups decreased, and the difference was statistically significant (P<0.05), decrease amplitude with dose of rosuvastatin increased became greater.Conclusion Rosuvastatin can significantly improve brachial artery endothelium-dependent vasodilation and carotid intima-media thickness in patients with coronary heart disease, and there is a clear dose-response relationship, which may be associated with rosuvastatin decrease total cholesterol and low-density lipoprotein cholesterol C in patients with coronary heart disease.It has guide significance to clinical.

Scutellarin attenuates endothelium-dependent aasodilation impairment induced by hypoxia reoxygenation, through regulating the PKG signaling pathway in rat coronary artery / 中国天然药物

Scutellarin (SCU), a flavonoid from a traditional Chinese medicinal plant. Our previous study has demonstrated that SCU relaxes mouse aortic arteries mainly in an endothelium-depend-ent manner. In the present study, we investigated the vasoprotective effects of SCU against HR-induced endothelial dysfunction (ED) in isolated rat CA and the possible mechanisms involving cyclic guanosine monophosphate (cGMP) dependent protein kinase (PKG). The isolated endothelium-intact and endothelium-denuded rat CA rings were treated with HR injury. Evaluation of endothelium-dependent and -independent vasodilation relaxation of the CA rings were performed using wire myography and the protein expressions were assayed by Western blotting. SCU (10-1 000 μmol·L(-1)) could relax the endothelium-intact CA rings but not endothelium-denuded ones. In the intact CA rings, the PKG inhibitor, Rp-8-Br-cGMPS (PKGI-rp, 4 μmol·L(-1)), significantly blocked SCU (10-1 000 μmol·L(-1))-induced relaxation. The NO synthase (NOS) inhibitor, NO-nitro-L-arginine methylester (L-NAME, 100 μmol·L(-1)), did not significantly change the effects of SCU (10-1 000 μmol·L(-1)). HR treatment significantly impaired ACh-induced relaxation, which was reversed by pre-incubation with SCU (500 μmol·L(-1)), while HR treatment did not altered NTG-induced vasodilation. PKGI-rp (4 μmol·L(-1)) blocked the protective effects of SCU in HR-treated CA rings. Additionally, HR treatment reduced phosphorylated vasodilator-stimulated phosphoprotein (p-VASP, phosphorylated product of PKG), which was reversed by SCU pre-incubation, suggesting that SCU activated PKG phosphorylation against HR injury. SCU induces CA vasodilation in an endothelium-dependent manner to and repairs HR-induced impairment via activation of PKG signaling pathway.

Effects of high-flux hemodialysis on fibroblast growth factor-23 and its clinical significance / 中华肾脏病杂志

Objective To investigate the effects of high-flux hemodialysis (HFD) on fibroblast growth factor-23 (FGF-23) levels in maintenance hemodialysis (MHD) patients and its clinical significance.Methods Sixty uremia patients were divided into HFD group and hemodialysis (HD)group and observed for 12 months.Flow mediated dilation (FMD),cardiac ultrasonography,levels of FGF-23,serum phosphorus,serum calcium,25-(OH)D3,parathyroid hormone (PTH),homocysteine (Hcy) and interleukin-6 (IL-6) were tested in all patients before and after treatment.The correlation of above indexes were analyzed.Results No statistical difference were found in primary disease,age and duration of dialysis in two groups.The levels of FGF-23 [(56.07±26.63) vs (85.53±40.54) ng/L,P ＜0.01],IL-6 [(3.37±2.48) vs (5.59±2.53) ng/L,P ＜ 0.05] and Hcy [(21.13±6.95) vs (29.40±11.66) μmol/L,P ＜ 0.05] decreased and FMD,25-(OH)D3 [(27.3± 10.26) vs (23.15± 10.73) μg/L,P ＜ 0.05] increased significantly after the treatment of HFD.There were no significant changes in the HD group.The baseline FMD was negatively correlated with FGF-23 (r =-0.413,P ＜ 0.05) and Hcy (r =-0.301,P ＜0.05).The baseline LVMI was correlated with FGF-23 (r =0.464 P ＜ 0.05).After one year's trearmeat of HFD,the changes of FMD(/△ FMD) was negatively correlated with the changes of FGF-23 (/△ FGF-23)(r =-0.347,P ＜ 0.05).Conclusions HFD can improve FMD and decrease FGF-23 levels.The improvement of FMD may be related to the decreased level of FGF-23.The effect of FGF-23 on FMD should be independent of serum phosphate.

Comparison of Endothelium-Dependent Vasodilation According to the Presence of Diabetes in Coronary Artery Disease

BACKGROUND AND OBJECTIVES: The purpose of this study is to evaluate endothelium dependent vasodilation in the diabetic patients suffering with coronary artery disease (CAD). SUBJECTS AND METHODS: 43 patients who presented with typical chest pain and who underwent coronary angiography were enrolled in this study. They were classified into diabetic patients with CAD (n=13), non-diabetic patients with CAD (n=13), diabetic patients without CAD (n=7), and non-diabetic patients without CAD (n=10), according to the presence of CAD and diabetes mellitus. Endothelium-dependent vasodilation of the brachial artery was measured in all the subjects by performing 7.5 MHz high-resolution ultrasound sonography. RESULTS: The endothelium-dependent vasodilation in the diabetic patients with CAD was 1.30+/-2.13% and it was 5.72+/-3.70% in the non-diabetic patients with CAD. There was a significant difference between the two groups (p=0.001). The endothelium-dependent vasodilation in diabetic patients without CAD was 2.28+/-1.88% and it was 10.70+/-10.19% in the non-diabetic patients without CAD. There was a significant difference between the two groups (p=0.029). The endothelium-dependent vasodilations in the diabetic group was 2.28+/-1.88% and it was 10.70+/-10.19% in the non-diabetic group for all the patients. There was a significant difference between the two groups (p=0.029). There was correlation between the endothelium-dependent vasodilation and the fasting blood sugar. There was negative correlation between the endothelium-dependent vasodilation and the fasting blood sugar (FBS) in the patients with CAD (r=-0.59, p=0.002). However, there was no correlation between the endothelium-dependent vasodilation and the FBS in the patients without CAD (r=-0.327, p=0.201). There was negative correlation between the endothelium-dependent vasodilation and the FBS in all subjects (r=-0.352, p=0.021). CONCLUSION: The endothelium-dependent vasodilation was decreased in the diabetic patients with CAD as compared to the non-diabetic patients with CAD. There was also was negative correlation between the endothelium-dependent vasodilation and the FBS in the patients with CAD.

Comparison of the lag time to initiation of flow-mediated vasodilation to endothelium-dependent vasodilation in early diagnosis of endothelial dysfunction

BACKGROUND: Endothelial dysfunction is an early event in atherogenesis. The conventional non-invasive methods, measuring flow mediated vasodilation at 1 minute after hyperemic condition, had some limitation. The purpose of this study is to evaluate the usefulness of initial reaction time(IRT) after hyperemic condtion as a new parameter of endothelial function. METHOD: Flow-mediated, endothelium-dependent vasodilation (FMD), endothelium-independent vasodilation (EID) and IRT were measured in 12 young diabetic patients(6 male and 6 female, mean age 26.3) and 12 age-matched healthy controls (6 male and 6 female, mean age 25.6), For the measurement of brachial arterial diameter, 7.5MHz ultrasound was used and for the continous monitoring of arterial diameter, specially designed fixing device was applied to the all subjects. RESULT: There were no significant difference in BMI (body mass index), mean age and blood pressure between normal control and young diabetic group. The FMD of young diabetic patients was lower than that of age-matched healthy controls (diabetic patients: 6.32.1%, healthy control: 8.92.7%, p<0.05). There was no significant difference in EID between normal control and young diabetic group. The IRT of FMD was significantly shorter in healthy control group than in young diabetic group (healthy control: 20.42.8 sec, diabetic group: 29.55.4 sec, p<0.0001). But IRT of EID showed no significant difference between normal control and young diabetic group. The IRT of FMD showed a significant negative correlation with FMD (r=-0.74, p<0.001) and HDL cholesterol level(r=-0.68, p<0.0001). CONCLUSION: These findings strongly suggest that IRT can also be used for early diagnosis of endothelial dysfunction.

Changes of plasma ox-LDL and endothelium-dependent vasodilation in patients with acute coronary syndrome / 中国实用内科杂志

Objective To explore the relationship of the plasma ox-LDL level and endothelium flow mediated vasodilation(FMD)in acute coronary syndrome patients(ACS).Methods From March to October 2004,in the Department of Cardiology,the Fourth PLA Hospital,51 patients with ACS were divided into 2 groups:AMI group(22patients)and UAP group(29 patients).20 subjects with normal coronary angiograms served as the control group.Nitrir oxide(NO)and plasma ox-LDL was measured by spectrophotometer and Sandwich ELISE method,respectively.The brachial arterial hyperemia-induced flow mediated vasodilation(FMD)and sublingual nitroglycerin(NTG)mediated vasodilation were measured by high resolution ultrasound.Results (1)The FMD in ACS group was significantly decreased compared with the control group[(7.2?1.42)、(7.6?1.12)vs(15.46?1.2),P0.05).(2)The No in ACS group was sigificantly lower than that in control group;the NO in AMI group was even lower[(48.46?12.44)、(60.42?10.30)vs(94.72?12.34)?mol/L,P1,which meant ox-LDL was a risk factor;the OR of FMD was

Effect of tissue kallikrein gene treatment on blood pressure in type 2 diabetic rats and its mechanism / 中国病理生理杂志

AIM: To study the effect of tissue kallikrein gene (HK) treatment on blood pressure in type 2 diabetic rats and its mechanism. METHODS: Male Wistar rats were injected with low dose streptozotocin and fed with diets enriched in fat and sugar to form type 2 diabetic model. Recombinant adeno-associated viral vectors (rAAV)-mediated HK gene (HK group) or LacZ gene (LacZ group) was introduced to the diabetic rats. The systolic blood pressure was measured every 2 weeks. The acetylcholine (Ach)-dependent vasodilation response, the synthesis of nitric oxide (NO), the expression of endothelin-1 (ET-1) and endothelin-A receptor (ET_A-R) in the aorta were detected. RESULTS: (1) Systolic blood pressure was significantly higher in diabetic rats than that in normal control rats. In HK group, systolic blood pressure was significantly reduced within 2 weeks after injection with rAAV?HK, reached near normal levels at 4 weeks and kept until the experiments ended (16 weeks). (2) In LacZ group, Ach-dependent vasodilation response of isolated aorta was markedly decreased than that in HK group (P