Asymmetric dimethylarginine, a biomarker of cardiovascular complications in diabetes mellitus

Cardiovascular(CV) complications are an essential causal element of prospect in diabetes mellitus(DM), with carotid atherosclerosis being a common risk factor for prospective crisis of coronary artery diseases and/or cerebral infarction in DM subjects. From another point of view, asymmetric dimethylarginine(ADMA) has been established as an inhibitor of endogenous nitric oxide synthesis and the relationship between ADMA and arteriosclerosis has been reported. In our study with 87 type 2 DM(T2DM) patients, we have examined whether ADMA and other CV risk factors are the useful predictors of DMCV complications. After the measurement of the respective CV risk factors, we have followed the enrolled T2 DM patients for 5 years. We have finally analyzed 77 patients. DMCV complications developed in 15 cases newly within 5 years, and 4 cases recurred. The concentrations of ADMA in plasma were markedly more elevated in 19 DM patients with CV complications than in 58 DM patients without CV complications. Urinary albumin(U-Alb), mean intimal-medial thickness(IMT) and ankle brachial index(ABI) were also higher in patients with CV complications. Multiple regression analyses showed that U-Alb had an influence on the high level of ADMA(standardized β = 6.59, P = 0.00014) independently of age, systolic BP, fibrinogen, mean IMT, plaque score, and ABI. The review indicates what is presently known regarding plasma ADMA that might be a new and meaningful biomarker of CV complications in DM subjects.

Liver plays a central role in asymmetric dimethylargininemediated organ injury

Asymmetric-dimethylarginine(ADMA) competes with L-arginine for each of the three isoforms of nitric oxide synthase:endothelial;neuronal;inducible.ADMA is synthesized by protein methyltransferases followed by proteolytic degradation.ADMA is metabolized to citrulline and dimethylamine,by dimethylarginine dimethylaminohydrolase(DDAH) and enters cells through cationic amino-acid transporters extensively expressed in the liver.The liver plays a crucial role in ADMA metabolism by DDAH-1 and,as has been recently demonstrated,it is also responsible for ADMA biliary excretion.A correlation has been demonstrated between plasma ADMA levels and the degree of hepatic dysfunction in patients suffering from liver diseases with varying aetiologies:plasma ADMA levels are increased in patients with liver cirrhosis,alcoholic hepatitis and acute liver failure.The mechanism by which liver dysfunction results in raised ADMA concentrations is probably due to impaired activity of DDAH due to severe inflammation,oxidative stress,and direct damage to DDAH.High plasma ADMA levels are also relevant as they are associated with the onset of multiorgan failure(MOF).Increased plasma concentration of ADMA was identified as an independent risk factor for MOF in critically-ill patients causing enhanced Intensive Care Unit mortality:a significant reduction in nitric oxide synthesis,leading to malperfusion in various organs,eventually culminating in multi organs dysfunction.

Effects of asymmetric dimethylarginine on renal arteries in portal hypertension and cirrhosis

AIM To evaluate the effects of asymmetric dimethylarginine(ADMA) in renal arteries from portal hypertensive and cirrhotic rats.METHODS Rat renal arteries from Sham(n = 15), pre-hepatic portal hypertension(PPVL; n = 15) and bile duct ligation and excision-induced cirrhosis(BDL; n = 15) were precontracted with norepinephrine, and additional contractions were induced with ADMA(10-6-10-3 mol/L), an endogenous inhibitor of nitric oxide(NO) synthase. Concentration-response curves to acetylcholine(1 × 10-9^(-3) × 10^(-6) mol/L) were determined in precontractedrenal artery segments with norepinephrine in the absence and in the presence of ADMA. Kidneys were collected to determine the protein expression and activity of dimethylarginine dimethylaminohydrolase(DDAH), an enzyme that catabolizes ADMA. RESULTS In renal arteries precontracted with norepinephrine, ADMA caused endothelium-dependent contractions. The pD 2 values to ADMA were similar in the Sham and PPVL groups(4.20 ± 0.08 and 4.11 ± 0.09, P > 0.05, respectively), but were lower than those of the BDL group(4.79 ± 0.16, P < 0.05). Acetylcholine-induced endothelium-dependent relaxation that did not differ, in terms of p D2 and maximal relaxation, among the 3 groups studied. Treatment with ADMA(3 × 10^(-4) mol/L) inhibited acetylcholine-induced relaxation in the 3 groups, but the inhibition was higher(P < 0.05) in the BDL group compared with that for the Sham and PPVL groups. The m RNA and protein expression of DDAH-1 were similar in kidneys from the three groups. Conversely, DDAH-2 expression was increased(P < 0.05) in PPVL and further enhanced(P < 0.05) in the BDL group. However, renal DDAH activity was significantly decreased in the BDL group. CONCLUSION Cirrhosis increased the inhibitory effect of ADMA on basal- and induced-release of NO in renal arteries, and decreased DDAH activity in the kidney.

Asymmetric dimethylarginine:A novel biomarker of gastric mucosal injury?

Nitric oxide(NO),a multifunctional endogenous gas molecule,is metabolized from L-arginine by enzymatic reaction in the presence of nitric oxide synthase.NO,an important gas signaling molecule,is a gastric mucosa protective factor that contributes significantly to maintain normal gastric mucosa integrity.NO increases gastric mucosa blood flow,regulates the secretion of mucus and bicarbonate,and inhibits the secretion of gastric juice.Asymmetric dimethylarginine(ADMA) has been identified as the major endogenous inhibitor of nitric oxide synthase.The function of ADMA is to decrease NO production via inhibiting nitric oxide synthase activity.Besides inhibiting NO synthesis,ADMA also directly induces oxidative stress and cell apoptosis,and participates in inflammation reaction.Its systemic accumulation was observed in conjunction with several cardiovascular and metabolic diseases.ADMA also mediates gastric ulcer injury induced by ethanol,stress,helicobacter pylori and indomethacin.The mechanism of ADMA directly producing adverse effect in gastric mucosa is incompletely understood.It is widely accepted that NO bioavailability decrease is the majority reason.Promotion of apoptosis and aggravation of inflammation may be other important mechanisms of ADMA-induced gastric injury.ADMA might be a novel clinical and experimental biomarker related to gastric mucosa disorder.Although therapeutic tool targeting to ADMA is available in multiple cardiovascular diseases,it is unknown in gastrointestinal disease.The strategy to inhibit ADMA is beneficial to gastric ulcer induced by ethanol in rats.Thus,ADMA might be a candidate of therapeutic target in gastric mucosa damage.

Transjugular intrahepatic portosystemic shunt-placement increases arginine/asymmetric dimethylarginine ratio in cirrhotic patients

AIM:To analyze the change of dimethylarginine plasma levels in cirrhotic patients receiving transjugular intrahepatic portosystemic shunt(TIPS).METHODS:To determine arginine,asymmetric dimethylarginine(ADMA),symmetric dimethylarginine(SDMA),and nitric oxide(NO) plasma levels,blood samples were collected from the superior cava,hepatic,and portal vein just before,directly after,and 3 mo after TIPS-placement.RESULTS:A significant increase in the arginine/ADMA ratio after TIPS placement was shown.Moreover,TIPS placement enhanced renal function and thereby decreased systemic SDMA levels.In patients with renal dysfunction before TIPS placement,both the arginine/ADMA ratio and creatinine clearance rate increased significantly,while this was not the case in patients with normal renal function before TIPS placement.Hepatic function did not change significantly after TIPS placement and no significant decline in ADMA plasma levels was measured.CONCLUSION:The increase of the arginine/ADMA ratio after TIPS placement suggests an increase in intracellular NO bioavailability.In addition,this study suggests that TIPS placement does not alter dimethylarginine dimethylaminohydrolase(DDAH) activity and confirms the major role of the liver as an ADMA clearing organ.

Determination of Asymmetric Dimethylarginine and Symmetric Dimethylarginine in Biological Samples of Mice Using LC/MS/MS

Herein, we present a novel method of asymmetric dimethylarginine (ADMA) and symmetric dimethylarginine (SDMA) determination within biological samples using protein precipitation and LC/MS/MS. Chromatographic separation of ADMA and SDMA was successfully performed using a silica column with optimized elution, or mobile phase, of 10 mM ammonium acetate buffer H2O/methanol/acetonitrile (20/30/45, v/v) at pH 4. The calibration ranges were 0.50 – 50.0 μg●mL-1, and good linearities were obtained for all compounds ( γ > 0.99). The intra- and inter-assay accuracies with recoveries and precisions at three concentration levels (i.e. 1.00, 5.00 and 25.0 μg●mL-1) were better than 86.9% and 7.36%, respectively. The analytical performance of the method was evaluated by determination of compounds in plasma, urine and tissues from male BALBc/J mice. For the first time, we were able to characterize the distribution of ADMA, SDMA and ADMA/SDMA in plasma, urine, brain, heart, kidneys, liver, lungs, pancreas and spleen. Additionally, we demonstrated that the ADMA/SDMA ratio in the brain was approximately 10-fold lower than all the other biological samples. Only 10 μL of plasma, 1 μL of urine and about 25 mg of tissues were required. These results suggest that the developed methodology was useful in ADMA and SDMA determination within biological samples.

Plasma Asymmetric Dimethylarginine Levels in Neonates with Bronchopulmonary Dysplasia Associated with Pulmonary Hypertension

Background: Bronchopulmonary dysplasia (BPD) continues to be an important problem in neonates especially premature infants despite improved facilities of care, monitoring and treatment. Pulmonary hypertension (PH) is a major complicating factor and key cause of mortality in this population. Altered vascular and alveolar growth particularly in canalicular and early saccular stages of lung development following mechanical ventilation and oxygen therapy result in arrest of the lung development leading to BPD with PH. Early recognition of PH in infants with these risk factors is important for optimal management. We tested the hypothesis that asymmetric dimethylarginine, would be greater in infants with bronchopulmonary dysplasia associated pulmonary hypertension than in infants with BPD alone. The Aim: The aim of the current study was to measure the Asymmetric dimethylarginine (ADMA) levels, arginine levels & the plasma arginine-to-ADMA ratio in newborn infants with broncho-pulmonary dysplasia, to evaluate echocardiographic parameters among neonates with bronchopulmonary dysplasia, to correlate between plasma ADMA & arginine-to-ADMA ratio and echocardiographic (ECHO) parameters in those patients and to compare full term & preterm neonates with bronchopulmonary dysplasia as regard to plasma ADMA level. Methods: A case-control study was carried out of ninety (90) newborns selected from those admitted to Neonatal Intensive Care Unit at Maternity & Children Hospital and Alzhraa University hospital during the period from October 2015 to March 2018. Neonates were divided into 2 groups: Patient with BPD with PH (cases group): It included 45 neonates with BPD & PH, 35 preterm neonates and 10 full term neonates. Patient with BPD only (Control group): It included 45 neonates with BPD without PH. These 45 neonates were divided as 22 preterm neonates and 23 full term neonates. Laboratory work was done in Alzhraa University hospital. Asymmetric dimethylarginine (ADMA) levels & arginine levels were measured using competitive enzyme linked immune-assay (ELISA). Results: Patients with both BPD and PH had greater plasma levels of ADMA than patients with BPD alone (P value 0.000). ADMA level > 186 ng/dl can predict development of PH in patient with BPD with sensitivity 100% and specify 100%. Preterm neonates with BPD had greater level of ADMA than full term neonates (P value 0.002). There was no statically significance difference between level of ADMA if withdrawn before or after 28 days of age (range of age at time of sampling in our study was 23 - 40 days) (P value 0.878), even ADMA level increased above the cut point early in the disease before we screened some cases by ECHO. There was no statically significance difference between level of arginine in cases and control groups with P value 0.530. The plasma arginine-to-ADMA ratio was lower in cases than in controls suggesting a greater likelihood of inhibition of nitric oxide production in patients with both BPD and PH than in patients with BPD alone (P value 0.000). ADMA level can predict severity of pulmonary hypertension in patient with BPD, as it was positively correlated with the grade of pulmonary hypertension (P value 0.006). ADMA level is higher in neonates with BPD and PH who died than those who survived;it can predict death in neonates with BPD &PH at cut off point > 643 ng/dl. Conclusion: ADMA increased in newborn infants with BPD, who developed PH. ADMA may have diagnostic and prognostic values. ADMA level was higher in preterm neonates than full term neonates and its level was correlated positively with severity of PH. ADMA levels were significant higher in infants with BPD with PH who died later than those who survived. There was no statically significance difference between levels of ADMA, whether it was drawn before or after 28 days of age (range 23 - 40 days). Echocardiographic screening and ADMA measurement could help in prevention of PH, diagnosis and early treatment of newborn infants suffering from BPD.

血清ADMA、IL-6、内毒素及乳酸在新生儿败血症所致感染性休克中的表达及临床意义

目的探讨血清不对称二甲基精氨酸(ADMA)、白细胞介素-6(IL-6)、内毒素及乳酸在新生儿败血症所致感染性休克中的表达及临床意义。方法选取我院收治的58例新生儿败血症所致感染性休克患儿为休克组,62例新生儿败血症未发生感染性休克患儿为败血症组,60例无感染新生儿为对照组。检测所有研究对象血清中的ADMA、IL-6、内毒素及乳酸水平。比较三组研究对象的ADMA、IL-6、内毒素及乳酸水平;分析ADMA、IL-6、内毒素及乳酸水平对新生儿败血症所致感染性休克患儿的诊断价值;分析ADMA水平与IL-6、内毒素及乳酸水平的关系;分析ADMA、IL-6、内毒素及乳酸水平与休克组预后的关系。结果休克组的ADMA、IL-6、内毒素及乳酸水平均高于败血症组及对照组(P<0.05);败血症组的ADMA、IL-6、内毒素水平均高于对照组(P<0.05);败血症组和对照组的乳酸水平无显著差异(P>0.05)。受试者工作特征曲线(ROC)结果显示,ADMA、IL-6、内毒素及乳酸诊断新生儿败血症所致感染性休克的曲线下面积(AUC)分别为0.93、0.89、0.89、0.92。Pearson相关性分析结果显示,ADMA水平与IL-6、内毒素及乳酸水平呈正相关(P<0.05)。ADMA、IL-6、内毒素及乳酸高水平与新生儿败血症所致感染性休克预后不良有关。结论血清ADMA、IL-6、内毒素及乳酸在新生儿败血症所致感染性休克中表达水平较高,可作为该疾病诊断的生物标志物并预测预后。

孕早期及孕中期血清PP-13和ADMA对子痫前期孕妇分娩方式的预测价值

目的分析孕早期、孕中期血清半乳糖凝集素-13(PP-13)、非对称性二甲基精氨酸(ADMA)对子痫前期孕妇分娩方式的预测价值。方法回顾性收集2020年1月至2022年12月在该院产科分娩的120例孕妇的临床资料,其中子痫前期孕妇76例,按照子痫前期严重程度分为轻度组52例、重度组24例,另选取同期正常孕妇44例作为对照组,采用酶联免疫吸附试验(ELISA)检测PP-13和ADMA水平。比较3组研究对象PP-13、ADMA水平,比较不同分娩方式孕妇PP-13、ADMA水平,绘制受试者工作特征(ROC)曲线分析PP-13、ADMA预测子痫前期孕妇分娩方式的效能。结果孕早期及孕中期PP-13水平均为重度组<轻度组<对照组,且任意两组间比较,差异均有统计学意义(P<0.05);而孕早期及孕中期ADMA水平均为重度组>轻度组>对照组,且任意两组间比较,差异有统计学意义(P<0.05)。剖宫产比例为重度组>轻度组>对照组,自然分娩比例及阴道助产比例为重度组<轻度组<对照组,且任意两组间比较,差异均有统计学意义(P<0.05)。自然分娩孕妇孕早期、孕中期PP-13水平均高于其他分娩方式孕妇,ADMA水平均低于其他分娩方式孕妇,差异均有统计学意义(P<0.05)。ROC曲线分析显示,孕早期PP-13、孕早期ADMA、孕中期PP-13、孕中期ADMA预测子痫前期孕妇自然分娩的曲线下面积(AUC)分别为0.806、0.963、0.781、0.673。结论孕早期PP-13、孕早期ADMA、孕中期PP-13可能可以用于子痫前期孕妇分娩方式的预测。

C1q、Lp-PLA2、ADMA对原发性高血压患者心血管事件发生风险的评估价值

目的 分析补体1q(C1q)、脂蛋白相关磷脂酶A2(Lp-PLA2)、非对称二甲基精氨酸(ADMA)对原发性高血压患者心血管事件发生风险的评估价值。方法 2021年1月至2023年2月新郑华信民生医院收治的156例原发性高血压并发心血管事件患者纳入研究组,另择同期168例原发性高血压未并发心血管事件患者纳入对照组。分析两组临床特征、常规生化指标、血清C1q、Lp-PLA2、ADMA水平,通过多因素分析法分析原发性高血压患者发生心血管事件的危险因素,绘制受试者工作特征(ROC)曲线分析相关指标对原发性高血压患者发生心血管事件的评估价值。结果 多因素logistic分析结果显示,体重指数(BMI)升高、合并糖尿病、高血压分级3级、血清Lp-PLA2及ADMA水平升高为原发性高血压患者发生心血管事件的危险因素(OR=1.988、2.063、2.020、2.083、2.326,P<0.05);血清C1q水平升高为原发性高血压患者发生心血管事件的保护因素(OR=0.534,P<0.05)。将原发性高血压患者发生心血管事件纳入阳性,未发生心血管事件纳入阴性,绘制ROC曲线分析C1q、Lp-PLA2、ADMA单独及联合检测对原发性高血压患者发生心血管事件的评估价值,曲线下面积(AUC)为0.785、0.852、0.781、0.916,敏感度为75.00%、79.49%、69.23%、89.74%,特异度为67.86%、79.76%、78.57%、81.55%,联合检测均最高。结论 原发性高血压患者心血管事件发生的危险因素包括BMI升高、合并糖尿病、高血压分级3级、血清C1q水平降低、Lp-PLA2、ADMA水平升高,C1q、Lp-PLA2及ADMA联合检测对原发性高血压患者心血管事件发生风险的评估价值较高,可为临床干预方案的选择提供依据。

虎杖苷对ADMA作用的正常兔主动脉血管条内皮功能的影响(英文)

目的 研究虎杖苷 (PD)与非对称性二甲基精氨酸 (ADMA)对正常兔主动脉血管条内皮功能的影响及PD与 ADMA之间的相互作用。方法 通过绘制主动脉条在 ADMA与 PD分别作用和共同作用时对苯肾上腺素(PE)的收缩量 -效曲线 ,计算并比较 Emax和 Kd值。结果 正常主动脉条对 ADMA无反应 ,PD或 ADMA预处理后亦不影响其对 PE的收缩反应。但 PD使受 ADMA预处理的主动脉条对 PE的收缩反应呈剂量依赖性减弱 ,并引起 K d值增大、Emax减小。结论 ADMA或 PD单独作用并不影响正常主动脉条的收缩功能及 PE对 α-受体的亲和力和 Emax;但在 ADMA存在时 ,PD能非竞争性拮抗主动脉条对 PE的收缩反应。

葛根素对氧自由基培养的脐静脉内皮细胞ADMA-DDAH系统的影响

目的观察葛根素对氧自由基(oxidized free radical,OFR)培养的人脐静脉内皮细胞(human um-bilical vein endothelial cells,HUVECs)二甲基精氨酸-二甲基赖氨酸水解酶(di methylarginine di methy-laminohydrolase,DDAH)活性及表达的影响,以探讨葛根素对不对称二甲精氨酸(ADMA)代谢机制的影响。方法采用改良的Jaffe法培养原代HUVECs,取生长良好的3～6代HUVECs用于实验,分为(1)空白对照组:加DMEM培养液;(2)OFR组:加入OFR0.1mmol/L;(3)葛根素Ⅰ组:加0.1mmol/L OFR及0.5mg/ml葛根素;(4)葛根素Ⅱ组:加0.1mmol/L OFR和1.0mg/ml葛根素。共孵24h后,检测上清液中NO、NOS活性、ET、ADMA含量、L-胍氨酸(L-cit)浓度,采用Western blotting测定细胞裂解液中DDAH的蛋白表达。结果OFR条件培养下,内皮细胞的代谢产物ADMA、ET含量均较空白对照组高,而NO及NOS的活性减少;反应DDAH酶活性的L-cit浓度显著降低,而DDAH的表达无明显变化。葛根素干预后,ADMA、ET含量较OFR组降低,NOS活性及NO增加,L-cit浓度明显升高。结论OFR培养下,内皮损伤ADMA的增加与DDAH的活性减弱有关,而与DDAH的表达无关。葛根素通过增加DDAH活性促进ADMA代谢,使NOS活性增加,抑制OFR对内皮功能的损伤。

氯沙坦保护ox-LDL诱导的内皮细胞损伤与ADMA的关系

目的：探讨氯沙坦对氧化型低密度脂蛋白（ox-LDL）诱导的内皮细胞损伤的保护作用及其与内源性一氧化氮合酶抑制物非对称性二甲基精氨酸（ADMA）的关系。方法：用ox-LDL（100mg／L）孵育人脐静脉内皮细胞株HUVEC12 24h或用10^-8～10^-6mmol／L的氯沙坦预孵育HUVEC12 30min后再与ox-LDL共孵育24h，测定培养液中乳酸脱氢酶（LDH）活性、一氧化氮（NO）、肿瘤坏死因子-α（TNF-α）、ADMA含量和细胞内二甲基精氨酸二甲胺水解酶（DDAH）活性。结果ox-LDL孵育HUVEC12细胞24h后细胞培养液中LDH活性、TNF-α和ADMA含量明显增加（P〈0．05），同时NO含量下降和细胞DDAH酶活性受到抑制（P〈0．05）；氯沙坦（10^-8～10^-6mmoL／L）可显著减轻ox-LDL诱导的LDH活性、TNF-α和ADMA含量的增加以及NO含量的降低（P〈0．05），并呈浓度依赖性的增加DDAH活性（P〈0.05）。结论：氯沙坦对ox-LDL诱导的血管内皮细胞损伤具有保护作用，该作用可能与增加DDAH活性，降低ADMA浓度有关。

氯沙坦通过降低ADMA水平诱导血管内皮保护作用

目的本实验拟观察在培养的人脐静脉内皮细胞,氯沙坦对血管紧张素Ⅱ（AngⅡ）诱导的血管内皮活化的保护作用是否与降低非对称二甲基精氨酸（ADMA）水平有关。方法用不同浓度的AngⅡ（10^-9-10^-6mol.L^-1）孵育不同时间（6-48 h）,并加入不同浓度的氯沙坦（1、3、10μmol.L^-1）预处理1 h,检测细胞培养上清液中的ADMA、一氧化氮（NO）、肿瘤坏死因子（TNF-α）水平,细胞中蛋白甲基转移酶（PRMT）蛋白表达、二甲基精氨酸二甲胺水解酶（DDAH）和活化蛋白（AP-1）活性。结果AngⅡ呈浓度和时间依赖性增加PRMT的表达,AngⅡ（10^-6mol.L^-1,24 h）显著增加培养液中ADMA、TNF-α水平,减少NO的生成,降低细胞DDAH活性,增加细胞AP-1活性。氯沙坦可拮抗AngⅡ所致的上述效应。结论这些结果提示氯沙坦诱导的血管内皮细胞保护作用可能与降低ADMA水平有关。

甲基莲心碱对LPC诱导内皮细胞损伤的保护作用及与ADMA的关系

目的:观察甲基莲心碱对溶血性磷脂酰胆碱(lysophosphatidylcholine,LPC)诱导血管内皮细胞损伤的保护作用及其与非对称性二甲基精氨酸(asymmetric dimethylarginine,ADMA)的关系。方法:10 mg.L-1的LPC孵育人脐静脉内皮细胞株(HUVEC-12)24 h或0.1,1.0,10.0μmol.L-1甲基莲心碱预处理HUVEC-12细胞1 h,再予LPC孵育细胞24 h,收集细胞上清液测定一氧化氮(NO)、丙二醛(MDA),ADMA含量和收集细胞测定细胞内活性氧(ROS)水平。结果:LPC孵育HUVEC-12细胞24 h后细胞上清液中MDA,ADMA含量及细胞内ROS水平显著性增加(P<0.05),细胞上清液中NO含量显著性降低(P<0.05);0.1,1.0,10.0μmol.L-1的甲基莲心碱预处理组ROS水平,MDA,ADMA含量显著降低,NO含量显著性升高(P<0.05)。结论:甲基莲心碱对LPC诱导的血管内皮细胞损伤有保护作用,该作用可能与其降低ADMA水平有关。

十两茶提取物抗高脂诱导家兔动脉粥样硬化形成涉及调节ADMA/NO通路

目的:观察十两茶提取物对高脂诱导家兔动脉粥样硬化的影响。方法:家兔高脂饲料喂养4周后,分别灌胃给予不同剂量的十两茶提取物(25、50和100mg/kg),共4周。实验结束后,颈动脉取血检测红细胞变形能力,测定血脂、NO、非对称二甲基精氨酸(ADMA)和丙二醛(MDA)含量;分离胸主动脉检测脂质斑块面积和血管内皮依赖性舒张功能。结果:十两茶提取物能剂量依赖性地降低高脂饲养家兔血清总胆固醇和低密度脂蛋白水平,同时显著减少主动脉粥样斑块面积和改善血管内皮舒张功能及红细胞变形能力。十两茶提取物显著降低血清MDA和ADMA含量和增加NO水平,且呈剂量依赖性。结论:十两茶提取物具有抗动脉粥样硬化作用,其机制与抑制脂质过氧化、调节ADMA/NO系统,改善血管内皮功能和红细胞变形能力有关。

酒精对大鼠血清NOS活性及ADMA含量的影响

目的研究不同浓度的酒精对大鼠血清中NOS活性及其内源性抑制物ADMA含量的影响。方法动物实验选用SD大鼠(雄性、56只、体重约250 g)灌胃给予不同剂量饮用酒处理组(红星二锅头,1 ml/100 g),每天一次,连续2个月,建立酒精摄入的动物实验模型。实验分为7组(n=8)。(1)对照组,(2)低、中、高三个剂量的饮用酒组(红星二锅头,14 V/V2、8 V/V5、6 V/V),(3)高脂饮食组,(4)高脂饮食联合中剂量饮用酒组(28 V/V):灌胃给予红星二锅头的同时,给予高脂饲料,(5)维生素E保护组,在(4)组基础上,每天给予维生素E(100 mg/kg,灌酒前1 h灌胃给予)。2个月后,按常规取动物血清,测定MDA、NO的含量与NOS(包括iNOS、eNOS、总NOS)的活性及ADMA含量。结果与对照组相比,酒精、高脂饮食、酒精联合高脂饮食能显著升高MDA、NO、ADMA含量,降低eNOS活性,升高iNOS活性;维生素E能扭转上述生物学效应。结论酒精能增加脂质过氧化产物,影响NOS活性,干扰NO代谢。其机制可能与内源性一氧化氮合酶抑制物ADMA水平有关。维生素E对其损伤有一定的保护作用。

AGXT2与ADMA代谢及心脑血管疾病的研究进展

心脑血管疾病严重威胁人类健康,有效预防和治疗心脑血管疾病是当代医学研究的重点。非对称性二甲基精氨酸(asymmetric dimethylarginine,ADMA)和对称性二甲基精氨酸(symmetric dimethylarginine,SDMA)是心脑血管疾病或心脑血管事件独立的预测因子。丙氨酸-乙醛酸转氨酶2(alanine-glyoxylate aminotransferase 2,AGXT2)是内源性ADMA的水解酶之一,其表达缺失或活性降低可影响体内ADMA的水平,而AGXT2的多个单核苷酸多态性与体内SDMA的水平明显相关。深入研究AGXT2在心脑血管疾病发生发展中的作用对以AGXT2为靶点开发新型心脑血管保护药物具有重要意义。该文就AGXT2参与ADMA的代谢及其与心脑血管疾病的最新研究进展进行综述。

NF-κB介导ADMA上调大鼠腹腔巨噬细胞LOX-1的表达

目的探讨非对称性二甲基精氨酸(ADMA)上调大鼠腹腔巨噬细胞的氧化低密度脂蛋白受体-1(LOX-1)表达是否受核因子-κB(NF-κB)的调控。方法分离培养大鼠腹腔巨噬细胞。实验分组:正常对照组,以含10%胎牛血清(FBS)DMEM培养液与巨噬细胞共孵育;氧化型低密度脂蛋白(oxLDL)组,在培养液中加oxLDL(50 mg/L);A+O组,在培养液中加ADMA(15μmol/L)和oxLDL(50 mg/L);P+A+O组,在培养液中加吡咯烷二硫代氨基甲酸盐(PDTC,25μmol/L)、ADMA(15μmol/L)o、xLDL(50 mg/L)。以实时荧光定量PCR(Real-time PCR)和Western blot分别检测LOX-1 mRNA和蛋白表达,以电泳迁移率变动分析(EMSA)和增强化学发光法(ECL)检测NF-κB活性。结果 oxLDL组与A+O组LOX-1 mRNA和蛋白表达比对照组明显增强,以A+O组尤为明显(均P<0.05);P+A+O组LOX-1mRNA和蛋白表达较A+O组降低(P<0.05)。与对照组相比,oxLDL组与A+O组NF-κB活性明显增强,以A+O组尤为明显(均P<0.05);P+A+O组NF-κB活性较A+O组降低(P<0.05)。相关分析:NF-κB活性与LOX-1 mRNA和蛋白表达量呈正相关(均为r=0.82,P<0.05)。结论 ADMA可能通过NF-κB途径增强LOX-1表达而促进巨噬细胞转化为泡沫细胞,促进动脉粥样硬化的发生发展。

ADMA/NOS/NO/cGMP通路系统在子痫前期患者母胎界面的表达及意义

目的:探讨ADMA/NOS/NO/c GMP通路系统在子痫前期患者母胎界面的表达及意义。方法:分别选取重度子痫前期、轻度子痫前期、妊娠期高血压患者各20例,另选同期行剖宫产的单胎初产健康妊娠妇女20例作为对照。检测并比较各组胎盘组织NO和c GMP水平、总NOS活性,免疫组化SP法检测胎盘组织e NOS和i NOS表达。高效液相色谱法检测各组脐静脉内皮细胞(Human umbilical vein endothelial cells,HUVECs)内ADMA水平。结果:重度、轻度子痫前期组胎盘组织NO水平分别为(7.6±3.6)μmol/g、(11.4±4.3)μmol/g,均显著低于对照组(均P<0.05);重度、轻度子痫前期组胎盘组织c GMP水平分别为(3.26±0.31)pmol/g、(4.53±0.42)pmol/g,均显著低于对照组(均P<0.05),且4组胎盘组织c GMP水平与NO水平呈正相关关系(r=0.672);重度、轻度子痫前期组胎盘组织总NOS活性分别为(10.4±3.0)、(14.8±1.6)U/mg蛋白质,显著低于对照组(均P<0.05),4组胎盘组织总NOS活性与NO水平呈正相关关系(r=0.785);重度、轻度子痫前期组胎盘组织e NOS表达显著低于对照组(均P<0.05),重度子痫前期组i NOS表达显著高于对照组(P<0.05);重度子痫前期、轻度子痫前期及妊娠期高血压3组HUVECs内ADMA水平均显著高于对照组(均P<0.05),且4组患者HUVECs内ADMA水平与胎盘组织NO水平呈负相关关系(r=-0.582)。结论:ADMA/NOS/NO/c GMP通路系统可能在子痫前期的发病中起重要作用。