Homocysteinylation of low-density lipoproteins (LDL) from subjects with Type 1 diabetes: effect on oxidative damage of human endothelial cells.

BACKGROUND: Homocysteine (Hcy) is an independent risk factor for cardiovascular disease (CVD). Individuals with Type 1 and Type 2 diabetes are more susceptible to the effects of homocysteine than non-diabetic subjects. The interaction between homocysteine-thiolactone (Hcy-thiolactone), a reactive product of Hcy, and low-density lipoproteins (LDL) induces the formation of homocystamide-LDL adducts (Hcy-LDL) and it has been suggested that homocysteinylation could increase atherogenicity of lipoproteins. AIM: The aim of the study was to compare the effect of in vitro homocysteinylation of LDL isolated from healthy control subjects (C-LDL) and from Type 1 diabetic patients (DM-LDL) and to investigate the effect of homocysteinylated LDL (Hcy-C-LDL and Hcy-DM-LDL) on peroxynitrite production of endothelial cells. METHODS: The in vitro homocysteinylation of LDL isolated from control (n = 12) and DM subjects (n = 12) was carried out by incubating lipoproteins with Hcy-thiolactone. The reaction was verified by quantifying the increase in sulphydryl groups (-SH groups) in Hcy-LDL with respect to control LDL. Control and homocysteinylated LDL were incubated with human aortic endothelial cells (HAEC) in culture. Peroxynitrite production in cells treated in different experimental conditions was assayed by a fluorimetric method. RESULTS: The increase in -SH groups after incubation with homocysteine was greater in LDL from diabetic subjects compared with LDL from control subjects (P < 0.001). In addition, peroxynitrite production from HAEC incubated with Hcy-LDL from diabetic patients was greater than after incubation with Hcy-LDL from control subjects and untreated LDL from diabetic patients (P < 0.001). CONCLUSIONS: These results show that LDL from diabetic patients is more susceptible to in vitro homocysteinylation than LDL from non-diabetic individuals and demonstrate that the compositional changes in Hcy-LDL from diabetic subjects have cytotoxic effects on human endothelial cells.     

冠心病患者血清同型半胱氨酸与叶酸、维生素B12水平的变化

目的 探讨冠心病患者血清同型半胱氨酸(HCY)与叶酸、维生素B12浓度的变化及其相关性。方法 选择84例经冠状动脉造影术证实为冠心病的患者，应用荧光偏振免疫分析法(FPIA)测定血清HCY浓度，离子捕获免疫分析法(ICIA)测定血清叶酸浓度，非均相微粒子酶免疫分析法（MEIA)测定血清维生素B12浓度。结果 冠心病患者血清HCY浓度增高，与正常对照组比较有显著性意义(P＜0．001)，而叶酸、维生素B12浓度则降低，与正常对照组比较有显著性意义(P＜0．001)，以上两种变化呈负相关(P＜0．001)。结论 同型半胱氨酸血症是冠心病的新的独立危险因素，叶酸、维生素B12缺乏可能是诱发高HCY的重要因素。     

同型半胱氨酸对胚胎海马神经元细胞的影响

目的 观察同型半胱氨酸(homocysteine，HCY)对海马神经元细胞分化和增殖的作用机理。方法 采用大鼠胚胎海马神经元细胞进行体外培养。观察不同浓度的HCY(0．01、0．1、1．0、10．0、100．0)mmol／L对细胞分化和增殖的影响。结果 随着剂量的增加．同型半胱氨酸对胚胎海马神经元细胞分化和增殖具有抑制作用，并用流式细胞术分析证明对脂质过氧化(LPO)的影响而使得神经元蛋白质含量增高。结论 同型半胱氨酸可抑制胚胎海马神经元细胞分化和增殖的影响，HCY可能在导致神经管畸形的过程起着重要作用。     

Thrombophilic risk factors and unusual clinical features in three Italian CADASIL patients

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a genetically transmitted cerebrovascular disease. Typically, the first clinical manifestation is migraine and the full clinical spectrum of the disease with recurrent strokes of the subcortical type, cognitive, and mood disorders is seen during the fourth and fifth decades of life. Vascular risk factors are usually absent in CADASIL patients and the diagnosis of the disease is particularly suspected in young adults with cerebrovascular events of unknown cause, diffuse leukoencephalopathy on computed tomography or magnetic resonance imaging, and a history of cerebrovascular diseases or dementia in many family members. We describe three Italian CADASIL patients who presented to medical attention for cerebrovascular events occurred after the age of 55 and had, in addition to hypertension and hyperlipidemia, thrombophilic risk factors such as hyperhomocysteinemia, elevated levels of lipoprotein(a), and antiphospholipid antibodies. Symptoms possibly related to cortical involvement, such as dysphasia and visual field deficits, were reported by two of these patients. We conclude that a diagnosis of CADASIL should not be disregarded in patients with vascular risk factors and presenting with symptoms not immediately referable to subcortical damage at ages more advanced than commonly reported.     

Evaluation of low serum vitamin B(12) in the non-anaemic pregnant patient

Low serum vitamin B(12) concentrations in pregnancy may not indicate true megaloblastic anaemia. In the present study we compared biochemical indices of vitamin B(12) deficiency (serum homocysteine and urine methylmalonic acid) in non-anaemic pregnant women with and without low serum vitamin B(12) concentrations. The groups were matched for age, parity and gestational age. No differences were found, and all values were within normal range. These results suggest that the measurement of low serum B(12) concentrations in pregnant women should be followed by analysis at the biochemical level before vitamin B(12) injections are started.     

The Effect of Omega-3 Fatty Acids on Thromboxane,Brain-Derived Neurotrophic Factor,Homocysteine, and Vitamin D in Depressive Children and Adolescents: Randomized Controlled Trial

In the DEPOXIN project, we have found that a high ratio of omega-6/omega-3 fatty acids (FA) is associated with worsening of depressive symptoms in children and adolescents with depressive disorder (DD) and that the 12-week omega-3 FA supplementation modulates DD symptoms. Here we present our results of the secondary outcomes: the levels of thromboxane (TXB), brain-derived neurotrophic factor (BDNF), homocysteine (HCy) and vitamin D. Fifty-eight patients were randomized into two arms. One group received a fish oil emulsion enriched with omega-3 FA, and the other received a sunflower oil emulsion containing omega-6 FA, for 12 weeks. Depressive symptoms were evaluated, using the Child’s Depressive Inventory (CDI). The patients with DD had elevated TXB levels and decreased vitamin D levels, as compared to healthy controls. Both CDI and omega-6/omega-3 ratio correlated positively with TXB and negatively with BDNF at baseline. Compared to the omega-6 FA group, the supplementation with omega-3 FA for 12 weeks significantly reduced plasma TXB (p = 0.024) and increased BDNF (p = 0.011) levels. No changes in HCy and vitamin D were observed. Our results demonstrate the possible role of TXB and BDNF in the pathophysiology of DD and the benefits of omega-3 FA supplementation. The study was registered with the ISRCTN registry (ISRCTN81655012).     

一种新的细胞凋亡相关基因——高同型半胱氨酸诱导基因HCY-2的功能初探

目的　探讨高同型半胱氨酸 (HCY)血症引起心血管病和出生性缺陷的作用机制。方法　采用诱导筛选方法克隆高同型半胱氨酸诱导基因 HCY- 2 ,以 Northern印迹分析检测 HCY- 2基因在大鼠不同组织中的表达 ,以免疫组化方法验证 HCY- 2蛋白在大鼠不同组织中的表达。结果　以诱导筛选方法从大鼠血管平滑肌细胞内克隆到一个新的全长 c DNA,即高同型半胱氨酸诱导基因 HCY- 2 ,它编码 142个氨基酸。Northern印迹分析和免疫组化检测表明 ,HCY- 2基因可在大鼠心、肾、脑、肝、肺等组织中广泛表达。在体外 ,将重组 HCY- 2基因转移至内皮细胞中 ,能够引起细胞凋亡和 DNA损伤 ;在体内 ,将 HCY- 2基因转移至鸡胚内 ,则诱发鸡胚细胞凋亡 ,并引起畸形。结论　 HCY- 2基因可能是一种新的凋亡基因 ,高同型半胱氨酸血症可能通过 HCY- 2基因诱发心血管病和出生性畸形。     

营养不良老年人与血浆同型半胱氨酸关系的研究

目的　探讨营养不良老年人治疗前后其体内同型半胱氨酸 (homocysteine ,HCY)的变化。方法　选 30例营养不良老年人患者 ,用维生素B6、维生素B12 和叶酸口服治疗 6周 ,分别检测治疗前后血浆HCY浓度。结果　治疗前 3d患者的HCY值与治疗 6周后检测的HCY值之间有显著性差异 ,P <0 .0 5。结论　营养不良的老年人通过积极的临床干预可以使血HCY回落。