BACKGROUND: Hyperhomocysteinemia is a new independent risk factor for coronary heart disease (CHD), but its association with cerebrovascular diseases is still controversial. The level of fasting plasma total homocysteine (plasma tHcy) alone is not enough to reveal the effect of hyperhomocysteinemia on cerebral infarction (CI).OBJECTIVE: To explore the association of hyperhomocysteinemia with folacin and vitamin B12 and with CI in young and middle-aged people, as well as the role of methionine loading test in the diagnosis of latent hyperhomocysteinemia.DESIGN: A case-control study, Spearman correlation analysis.PARTICIPANTS: A total of 85 patients were hospitalized within 2 days after the onset of CI at the Department of Neurology, the General Navy Hospital of Chinese PLA, from 2000 to 2003. There were 63 males and 22females aged 29-55 years old with the mean age of (48.74±5.05) years.There were 48 cases of lacunar CI and 37 cases of arterial thrombotic CI.Meanwhile, 44 normal controls, 30 males and 14 females aged 29-55 years old with the mean age of (47.75±6.71), were recruited from the department staff and those who came to the hospital for routine health examination.METHODS: Fasting vein blood of 6 mL was collected from the patients on the 1st day of hospitalization, and 2 mL of the blood was used for detecting the level of fasting plasma tHcy using high efficiency liquid chromatography. Methionine of 0.1 g/kg was taken orally by patients immediately after blood sampling; 4 hours later, the level of loading plasma tHcy was also determined. The remaining 4 mL was used for detecting the level of serum folacin and vitamine B12 with bioradiation assay.MAIN OUTCOME MEASURES: ① The level of fasting and loading plasma tHcy in CI group and control group. ② Incidence of hyperhomocysteinemia in CI group and control group [Hyperhomocysteinemia was confirmed if hyperhomocysteine was higher than 95% of the upper limit of fasting plasma tHcy or 4-hour loading plasma tHey of normal control group, that is, fasting plasma tHcy ＞17.26 μnol/L in males and ＞14.17 μnol/L in females; and loading plasma tHcy should be ＞ 44.57 μmol/L in males and ＞ 40.02 μmol/L in females. ③ The level of serum folacin and vitamine B12 in CI group and control group. ④ Single factor analysis of fasting plasma tHcy and related risk factors.RESULTS: Totally 85 CI patients and 44 normal controls were recruited in this study and all data were statistically analyzed. ① The level of fasting and loading plasma tHcy in CI group and control group: Both fasting and loading plasma tHcy was significantly higher in CI group than in control group [(22.49±9.80), (13.08±2.33) μmol/L; (48.07±11.20), (37.23±3.48)μmol/L, (t=8.409, 8.187, P ＜ 0.01)]. ② Incidence of hyperhomocysteinemia: The incidence was obviously higher in CI group than in control group [68% (58/85), (9%, 4/44), X2=40.628, P ＜ 0.01]. Totally 35 patients (41%, 35/85) had higher fasting plasma tHcy than that of normal controls, and 23 (27%, 23/85) had higher loading plasma tHcy than that of normal controls. ③ The level of serum folacin and vitamine B12 in CI group and control group: They were [(5.73±2.52), (7.14±2.20) μg/L] in CI group,significantly lower than control group [(473.47±190.19), (576.70±212.05) rng/L,(t =3.151, 2.809, P ＜ 0.01)]. ④ Single factor analysis of plasma tHcy with related risk factors: Fasting and loading plasma tHcy was found obviously associated with sex, and folacin and vitamine B12 level (r = -0.306 to 0.488, P ＜ 0.01), but not with other risk factors and neurological deficit scores (r = 0.021-0.173, P ＞ 0.05). Moreover, only plasma tHcy level was proved to have significant positive correlation with fasting blood glucose (r=0.186, P ＜ 0.05).CONCLUSION: Hyperhomooysteinemia is an independent risk factor for CI in young and middle-aged people. Methionine loading test is an essential means for detecting latent hyperhomocysteinemia. Insufficiency of folacin and vitamine B12, two important nutrition factors, may lead to hyperhomocysteinemia and indirectly result in CI.

Objective To study the value of methionine loading test (MLT) in the mild vascular cognitive impairment (VCI) after acute cerebral infarction.Methods The fasting plasma homocystine (Hcy) level and homocystine level after MLT were measured by high-performance liquid chromatography methods.We chose 240 patients with normal level of fasting plasma Hcy (normal group),159 patients with normal level of Hcy after MLT,81 patients with hyperhomocysteinemia after MLT (hyperhomocysteinemia group),and 112 patients with fasting hyperhomocysteinemia (fasting hyperhomocysteinemia group) in this study.The Montreal Cognitive Assessment (MoCA) and Mini-Mental State Examination (MMSE) were conducted in normal,hyperhomocysteinemia and fasting hyperhomocysteinemia groups on admission,at 7d,14 d,30 d after treatment.Results Logistic regression analysis showed that the increased level of Hcy might be an independent risk factor for VCI [OR:1.285,95％CI:1.038-1.265,P＜0.05].The scores of MMSE and MoCA were lower in patients with fasting hyperhomocysteinemia and patients with hyperhomocysteinemia after MLT than in patients with normal fasting plasma Hcy at 7 d,14 d and 30 d after treatment (P＜0.01 or 0.05),while the scores had no significant differences among the three group on admission (P＞0.05).There were no significant differences in MMSE and MoCA scores between patients with fasting hyperhomocysteinemia and patients with hyperhomocysteinemia after MLT on admission,7 d,14 d and 30 d after treatment (P＞0.05).Conclusions Hcy may be an independent risk factor for VCI.The MLT can discover the dormant vascular risk factors for VCI,which offers a valuable detection method for early intervention and prevention in the clinical medicine.

Objective To evaluate the effect of the plasma homocystine (Hcy) after methionine loading test (MLT) on the recurrence of ischemic vascular event,including cerebral infarction,transient ischemic attack (TIA),acute coronary syndrome,other vascularembolism,in cerebral infarction patients.Methods The fasting plasma homocystine (FHcy) and homocystine after MLT (PHcy) levels were measured by high-performance liquid chromatography.383 cerebral infarction patients with normal Hcy level were selected and divided into hyperhomocysteinemia after MLT (PHcy) group (n=135) and non-hyperhomocysteinemia after MLT (NPHcy) (n=248).Recurrence rates of ischemic vascular events within a 5-years follow-up period was observed.Results The levels of FHcy,PHcy and △Hcy (PHcy level subtracted FHcy level) were higher in males than in females in the two groups (all P＜0.05).The recurrence rates of cerebral infarction/TIA,acute coronary syndrome and other vascular embolism events were higher in PHcy group than in NPHcy group within the follow-up period (all P＜0.05).By forward stepwise logistic analysis,we found that the increased PHcy and △Hcy levels were the independent risk factors for recurrent ischemic vascular events [odds ratio (OR):0.509,2.107,95％ confidence interval (CI):0.286-0.904,1.185-3.745,both P＜0.05].Conclusions PHHcy may be an independent risk factor for recurrence ischemic vascular events in cerebral infarction.

Objective To explore the possible effect of the plasma homocysteine level on the risk of recurrent cerebral infarction patients by follow-up research in hope for finding a new theoretical evidence for the therapy and the prophylaxis of cerebral infarction.Methods We determined the free plasma total homocysteine(tHcy)of 151 patients with acute cerebral infarction and 52 age-and gender-matched healthy controls by high-performance liquid chromatography,then we divided the patients into hyperhomocysteinemia (Hhcy)group and no hyperhomocysteinemia(Nhhcy)group according to the outcome.Within a 5-years follow-up period,we observed the recurrence of cerebral infarction in the 2 groups.Results There was no statistical deference in common information between Hhcy and Nhhcy group.But the recurrence rate of the Hhcy group,being 44.26%,was significantly higher than 12.22%of Nhhcy group(P