Beclin 1 knockdown retards re-endothelialization and exacerbates neointimal formation via a crosstalk between autophagy and apoptosis.

OBJECTIVE: Endothelial regeneration is an essential process for the prevention of excessive neointimal formation following endothelial denudation. Beclin 1, a mammalian autophagy gene, is a link between autophagy and apoptosis. We hypothesized that the interference of Beclin 1 can influence re-endothelialization and ultimately affect neointimal formation by regulating autophagy and apoptosis. METHODS: A rat carotid injury model of endothelial denudation was used, and small interfering RNA of Beclin 1 was perivascularly administered. Neointima was evaluated by morphological analysis. von Willebrand factor, Beclin 1, LC3, autophagic substrate p62 and caspase-3 levels were detected by immunofluorescence or Western blotting. Terminal deoxynucleotidyl transferase-mediated digoxigenin-dUTP-biotin nick-end labeling assay was performed to evaluate apoptosis. RESULTS: Carotid injury induced an upregulation of Beclin 1 protein which was down regulated by more than 50% with small RNA interference. Beclin 1 knockdown significantly retarded re-endothelialization 7 days after injury and subsequently augmented neointima by more than 2 folds at 14 and 21 days. Autophagy and apoptosis were detected to reveal the regulatory effect of Beclin 1. The injury-activated autophagy, shown by the increased levels of punctate LC3 and LC3II as well as decreased p62 expression, was significantly inhibited by Beclin 1 knockdown. Meanwhile, the apoptotic endothelial cell number was increased and caspase-3 was up-regulated, though the expression of truncated BID was not significantly influenced. CONCLUSION: Beclin 1 knockdown exacerbated neointimal formation after rat carotid injury, associated with retarded re-endothelialization due to enhanced apoptosis, while simultaneously prohibiting autophagic activation. The data suggested an essential role of Beclin 1 as a regulator between autophagy and apoptosis in the setting of neointimal formation.

Stroke-prone renovascular hypertensive rat as an animal model for stroke studies: from artery to brain.

High blood pressure is a main risk factor for both initial and recurrent stroke. Compared to the post stroke situation in normotension, the brain lesion is larger in hypertension, and the treatments may not be as effective. Thus, the results from healthy individuals may not be directly applied to the hypertensive. In fact, the high prevalence of hypertension in stroke patients and its devastating effect urge the necessity to integrate arterial hypertension in the study of stroke in order to better mimic the clinical situations. The first step to do so is to have an appropriate hypertensive animal model for stroke studies. Stroke-prone renovascular hypertensive rat (RHRSP) introduced in 1998, is an animal model with acquired hypertension independent of genetic deficiency. The blood pressure begins to increase during the first week after constriction of bilateral renal arteries, and becomes sustained since around the 3rd month. Because the morphological and physiological changes of cerebral arteries are similar to those in hypertensive patients, the rats represent a higher than 60% incidence of spontaneous stroke. The animal model has several advantages: one hundred percent development of hypertension without gene modification, high similarity to human hypertension in cerebrovascular pathology and physiology, and easy establishment with low cost. Thus, the model has been extensively used in the investigation of ischemic stroke, and has been shown as a reliable animal model. This paper reviewed the features of RHRSP and its applications in the treatment and prevention of stroke, as well as the investigations of secondary lesions postischemic stroke.

[Response to thymectomy and analysis of influencing factors in the treatment of children with myasthenia gravis].

OBJECTIVE: To evaluate the efficacy of thymectomy and relevant influencing factors in the treatment of children with myasthenia gravis through a long-term follow-up. METHODS: The clinical records of 59 patients undergoing expanded thymectomy for the treatment of myasthenia gravis (MG) between January 2003 and August 2009 were reviewed retrospectively. Their postoperative outcomes were categorized into complete stable remission (CSR), pharmacological remission (PR), improvement, no change and deterioration (including mortality). RESULTS: During a median follow-up period of 35 months, none of them died or deteriorated clinically among 53 patients with a postoperative follow-up. The overall remission rate was 69.8% and the effective rate 90.6%. No symptomatic relapse occurred among 16 patients in CSR. None of the ocular patients progressed to generalized MG while 16 thymectomized generalized MG developed from ocular MG. Both univariate and logistic regression analyses revealed that the preoperative duration of illness influenced the surgical curative effect (P < 0.05). Survival analysis indicated that the rates of overall remission were 56% or 88% at 24 months and 42% or 75% at 48 months among ocular MG and generalized MG respectively. According to Log-rank analysis, no difference in remission existed between two types of MG. CONCLUSION: Thymectomy is an effective and safe treatment in selected MG children, especially in those with a shorter illness duration.

Marine cyclotripeptide X-13 promotes angiogenesis in zebrafish and human endothelial cells via PI3K/Akt/eNOS signaling pathways.

Cyclotripeptide X-13 is a core of novel marine compound xyloallenoide A isolated from mangrove fungus Xylaria sp. (no. 2508). We found that X-13 dose-dependently induced angiogenesis in zebrafish embryos and in human endothelial cells, which was accompanied by increased phosphorylation of eNOS and Akt and NO release. Inhibition of PI3K/Akt/eNOS by LY294002 or L-NAME suppressed X-13-induced angiogenesis. The present work demonstrates that X-13 promotes angiogenesis via PI3K/Akt/eNOS pathways.

A method of evaluating the lower limit of cerebral autoregulation and its correlation with blood pressure by transcranial Doppler in rats.

The aim of present study was to validate the assessment of lower limit of cerebral autoregulation (LLCA) as derived from mean artery blood pressure (MABP) and cerebral zero flow pressure (ZFP) by means of transcranial Doppler (TCD) and to determine the accurate relationship between LLCA and MABP in stroke-prone renovascular hypertensive rats (RHRSP). We studied two groups of rats: RHRSP and normal controls. Blood flow velocity of middle cerebral artery was monitored by TCD and arterial blood pressure was recorded in right femoral artery to compute the ZFP. The value of LLCA was determined as the difference between MABP and ZFP and validated by the value determined by blood withdrawal-induced cerebral autoregulation. In normal rats, the LLCA derived from the new method was 69.8 ± 8.7 mm Hg, from the change of blood velocity was 69.4 ± 9.8 mmHg and from blood volume flow after blood withdrawal was 68.8 ± 9.7 mmHg. In the RHRSP group, the corresponding values of LLCA were 109.1 ± 17.2 mm Hg, 110.0 ± 18.0 mm Hg and 109.0 ± 19.3 mm Hg, respectively. In each group, there was no statistically significant difference among the three values. LLCA in RHRSP began to increase 6 weeks after hypertension-induced operation, significantly higher than controls (p < 0.05), and stabilized at 110 mm Hg, 10 weeks after operation. The increase of LLCA was positively correlated with MABP, following an "S" curve, demonstrating that the change of LLCA was more obvious in the middle range of MABP in RHRSP (R(2) = 0.8848, p < 0.05). In conclusion, TCD is a valid and noninvasive method for determination of LLCA compared with the classic method in rats. Our data demonstrated that the change of LLCA may be correlated with MABP, following an "S" curve relationship.

dl-3n-Butylphthalide promotes angiogenesis via the extracellular signal-regulated kinase 1/2 and phosphatidylinositol 3-kinase/Akt-endothelial nitric oxide synthase signaling pathways.

We have previously demonstrated that dl-3n-butylphthalide (NBP) has a potential angiogenic activity. In this study, we investigated the angiogenic effect of NBP and the molecular mechanisms underlying NBP-mediated angiogenesis. Zebrafish embryos and human umbilical vein endothelial cells were treated with various doses of NBP and several signaling pathway inhibitors. NBP induced ectopic subintestinal vessel production in zebrafish embryos and induced invasion, migration, and endothelial cell tube formation of human umbilical vein endothelial cells in a dose-dependent manner. These NBP-induced angiogenic effects were partially suppressed by SU5402, a fibroblast growth factor receptor 1 inhibitor; U0126, an extracellular signal-regulated kinase 1/2 (ERK1/2) inhibitor; LY294002, a phosphatidylinositol 3-kinase inhibitor; 1L6-hydroxymethyl-chiro-inositol-2-(R)-2-O-methyl-3-O-octadecyl-sn-glycerocarbonate, an Akt inhibitor; cavtratin, an endothelial nitric oxide synthase (eNOS) inhibitor and completely inhibited by a combination of U0126 and LY294002. NBP enhanced phosphorylation of ERK1/2 and fibroblast growth factor receptor 2 expression, which were inhibited by U0126. NBP increased the phosphorylation of Akt and eNOS at serine 1177, which was blocked by LY294002. NBP-stimulated nitric oxide production, which was reduced by LY294002. Our data demonstrated that (1) NBP promoted angiogenesis and (2) the angiogenic effects of NBP were mediated by the ERK1/2 and phosphatidylinositol 3-kinase/Akt-eNOS signaling pathways. Our findings suggest that NBP could be a novel agent for therapeutic angiogenesis in ischemic diseases.

A retrospective review of 15 patients with familial myasthenia gravis over a period of 25 years.

We observed, during a 25-year period, 15 patients from 6 families with autoimmune myasthenia gravis (all Chinese Han from Guangdong Province) referred to our department. Their mean onset age was 13.4 years (range 2-25 years) with 10 patients with juvenile onset. The female:male ratio was 3:2. Acetylcholine receptors antibody titers were increased in 11 patients (range 1.62-19.8 nmol/L). Thymectomy was performed in six patients, who received corticosteroids /immune inhibitor plus pyridostigmine treatments after surgery. The other patients were placed on therapy with azathioprine, cyclophosphamide, corticosteroids and acetylcholinesterase inhibitors. All patients responded well to immunosuppressants, and psychiatric symptoms were observed only in one patient who received a high dose of corticosteroids. Patients with generalized type in the same family had different presentations with variable prognosis. HLA-A 0207 was found in 9 patients (9/15), HLA-B 4601 in 11 patients (11/15), and HLA-DRB1 0901 in 12 patients (12/15). When compared to familial autoimmune myasthenia gravis in other countries, we observed peculiar characteristics of Chinese populations, such as the within-family consistency was only found in families with ocular MG type (50% of all MG families), while the pathogenetic conditions and the prognoses of the generalized MG patients may differ greatly within the same family. These findings may shed new light on the genetic predisposition and the origin of immune abnormalities of MG patients.

[Correlation study between Chinese myasthenia gravis patients from Guangdong province and the polymorphism of HLA immunogene].

OBJECTIVE: To explore the correlation between Chinese myasthenia gravis (MG) patients from Guangdong province and the polymorphism of HLA immunogene. METHODS: The genotypes of HLA-A, B and DRB1 alleles in 104 MG patients and 121 healthy blood donors were detected by PCR-SBT (polymerase chain reaction-sequencing-based typing). RESULTS: (1) There were 15 alleles at A locus, 32 at B locus and 23 at DRB1 locus in MG group. (2) The frequency of HLA-A*02:07(P = 0.000, RR = 3.715), -B*46:01(P = 0.000, RR = 5.698), -DRB1*04:03(P = 0.033, RR = 6.312), -DRB1*09:01(P = 0.000, RR = 5.884) in MG patients was higher than that in healthy controls. (3) There were positive associations of HLA-DRB1*09:01(P = 0.000, RR = 1.349) with juvenile-onset ocular MG. CONCLUSION: There is susceptibility association of HLA-A*02:07, -B*46:01, -DRB1*04:03, -DRB1*09:01 with Chinese MG patients from Guangdong province. There is a close genetic and immunological correlation between HLA alleles and the pathogenesis of MG. It has directional significance in the race and region incidence study, clinical classification, differential diagnosis, treatment and prognosis of MG.

[Therapeutic efficacy and safety of tacrolimus for intractable myasthenia gravis: a report of 36 patients].

OBJECTIVE: To examine the efficacies and adverse events of low-dose tacrolimus in intractable myasthenia gravis (MG) patients during a long-term follow-up. METHODS: Tacrolimus was administered at 0.1 mg×kg(-1)×d(-1) to 36 generalized or ocular MG patients at our department from November 2008 to December 2010. The efficacies of tacrolimus were assessed by the myasthenia gravis activities of daily living (MG-ADL) profile and the classification of Myasthenia Gravis Foundation of America (MGFA). And the adverse events of tacrolimus were monitored in each patient. RESULTS: (1) All patients were followed up for 7 - 23 months. Adverse events occurred in 6 patients (16.67%). (2) The myasthenic symptoms improved up to the levels of MG-ADL and MGFA in 24 patients (66.67%). There was notable statistical significance in the comparison of clinical status at pre- and post-treatment (P = 0.000). (3) The efficacies in patients with generalized MG were better than those with ocular MG (P = 0.032). (4) The average blood trough levels of tacrolimus were lower than the recommended maintenance range from other countries in 24 effective patients. CONCLUSION: The administration of tacrolimus induces symptomatic improvements in MG patients especially in generalized type. And the adverse events should be closely monitored.

[Roles of Bacillus Calmette-Guérin with immunological memory in the pathogenesis of myasthenia gravis].

OBJECTIVE: To explore the roles of immunological memory in the pathogenesis of myasthenia gravis (MG) by Bacillus Calmette-Guérin (BCG). METHODS: For this randomized comparative clinical trial, 58 newly diagnosed MG patients and 32 age-and-gender-matched healthy controls were analyzed by purified protein derivative (PPD) test. The results were observed after 72 hours. peripheral blood mononuclear cell (PBMC) was collected from the MG patients before and after extended thymectomy and cultured with BCG. After a 72-hour incubation, the level of interferon gamma (IFN-γ) was detected by enzyme-linked immunosorbent assay (ELISA). RESULTS: In PPD test, the MG patients did not show a markedly higher positive percentage [48.3% (28/58) vs 65.6% (21/32), P = 0.114]. The pre-thymectomy PBMC had a higher level of IFN-γ than the control group: (650 ± 312) pg/ml vs (346 ± 153) pg/ml. After extended thymectomy, the level of IFN-γ returned to normal: (219 ± 113) pg/ml. The P value is 0.003, 0.001. CONCLUSION: The impairment of immunological memory, may be an important pathogenic cause of relapse in the MG patients.

[Analysis of prognostic factors and efficacy of plasmapheresis in the treatment of myasthenia crisis].

OBJECTIVE: To examine the prognostic factors and efficacy of myasthenia gravis (MG) in crisis on plasmapheresis and detect the reasons for ineffective plasmapheresis. METHODS: The investigators analyzed a total of 69 MG patients in crisis on plasmapheresis by case control study. Gender, age at onset of myasthenic symptoms, duration between the onset of crisis and plasmapheresis, pre-therapeutic use of glucocorticoids, pulmonary infections, other complications, nutritional status, history of thymectomy in 48 hours before crisis, thymic pathology, combined intravenous immunoglobulin (IVIG) and total sessions of plasmapheresis were measured retrospectively. RESULTS: Univariate analysis showed that pulmonary infections (P = 0.000, OR = 29.250), history of thymectomy in 48 hours before crisis (P = 0.046, OR = 0.267), combined intravenous immunoglobulin (P = 0.003, OR = 0.136) and total sessions of plasmapheresis (P = 0.022, OR = 0.498) were all influencing factors of plasmapheresis. However the analysis of multivariate logistic regression revealed that pulmonary infections (P = 0.000, OR = 23.600) was an independent risk factor and combined intravenous immunoglobulin (P = 0.047, OR = 0.192) was an independent protection factor of plasmapheresis. CONCLUSION: Plasmapheresis is ineffective in MG crisis with pulmonary infections. Control of pulmonary infections and combined intravenous immunoglobulin can improve the response to plasmapheresis in patients with MG crisis.

Relationship between cerebral hypoxic tissue volume and prognosis after stroke.

BACKGROUND/AIMS: Between 50 and 70% of stroke survivors suffer from severe disabilities such as paralysis and aphasia. Poor stroke outcome is a reflection of our incomplete understanding of the underlying mechanisms, and hence the capacity to implement appropriate treatment(s). We evaluated hypoxic tissue after stroke and patient condition severity and prognosis. METHODS: Hypoxic tissue volume was quantified within 14 days after stroke. Patients were classified as hypoxic positive or negative. Patients were evaluated at imaging and 21 days later. Prognosis was assessed at 30 and 90 days. RESULTS: Significant improvement was shown in hypoxia-positive (vs. hypoxia-negative) patients (p < 0.05). There were significant positive relationships between the volume of hypoxic tissue and the improvement in specialized test scores at 90 days (p < 0.05 for both). Presence of hypoxic tissue within 14 days after cerebral stroke was related to recovery at 3 weeks and prognosis at 90 days. CONCLUSIONS: The assessment of hypoxic tissue volume after stroke may be useful in predicting patient recovery.

Enhanced angiogenesis with dl-3n-butylphthalide treatment after focal cerebral ischemia in RHRSP.

Appropriate restoration of blood flow via angiogenesis is critical for the recovery from ischemic stroke. Previously, we reported that treatment with dl-3n-butylphthalide (NBP) increases the number of local potent cerebral microvessels. However, the underlying mechanism remained unclear. The present study was conducted to test whether NBP enhances post-ischemic cerebral angiogenesis via vascular endothelial growth factor (VEGF) and hypoxia induced factor-1 alpha (HIF-1 alpha). Stroke-prone renovascular hypertensive rats (RHRSP) were used to create middle cerebral artery occlusion (MCAO) model. NBP was given 80 mg/kg per d for 10 consecutive days, starting 12, 24, 48 and 72 h respectively after MCAO. Neurological function was assessed daily and infarct volume as well as the expressions of CD31, VEGF, HIF-1 alpha and bFGF was detected 13 days after MCAO. The administration of NBP starting within 24 h after MCAO enhanced recovery of neurobehavioral function, reduced infarct volume, increased the quantity of CD31 positive vessels, and up-regulated expressions of VEGF and HIF-1 alpha. These findings suggest that treatment with NBP within 24 h post-ischemic stroke rescues brain tissue by enhancing angiogenesis associated with up-regulation of VEGF and HIF-1 alpha expressions.

[Expression of regulatory T cells in thymus of myasthenia gravis patients].

OBJECTIVE: To investigate the in situ expression of regulatory T cells (Tregs) in thymus and its significance for myasthenia gravis (MG). METHODS: Thirty nine MG patients who had not accepted immunosuppressive therapy before thymectomy were recruited as study group and 19 patients undergoing cardiosurgery as control. There was no significant statistical difference in age and gender between the two groups (P > 0.05). The location and proportion of Tregs in thymus were analyzed using indirect immunofluorescence double labeling immunohistochemistry and image analysis software. RESULTS: (1) Tregs were all located in medulla zone of thymus in control and MG groups. (2) Cells of germinal center had a high expression of CD25 and a low expression of CD4. It indicates that a majority of germinal center cells were B cells. (3) There were fewer Tregs around germinal center. (4) There was no statistical significant difference in absolute number of Tregs between the two groups (P > 0.05). But the proportion of Tregs was higher in control group (P < 0.05). CONCLUSION: The proportion of thymus Tregs decreases in MG so as to weaken the function of immuno-regulation and suppression. This is probably a precipitating factor of MG.

[Mediation of cellular immune response by TP5 in pathogenesis of myasthenia gravis].

OBJECTIVE: To evaluate the effects of TP5 upon the production of IFN-gamma and different T cell subsets by human peripheral blood mononuclear cells (PBMCs) from patients with myasthenia gravis (MG) and to provide experimental rationales for TP5 in clinical therapy of MG. METHODS: PBMCs were isolated from peripheral blood of MG individuals and cultured with anti-CD3. The level of IFN-gamma in culture supernatants was examined by ELISA. The subsets and frequency of IFN-gamma-producing cells were examined at a single-cell level by flow cytometry. RESULTS: After PBMCs stimulation with anti-CD3 and TP5 (300 microg/ml), the level of IFN-gamma expression was significantly inhibited (P(child) = 0.0001, P(adult) = 0.01); and the level of IFN-gamma expression from normal adult and child controls was also significantly inhibited (P(child) = 0.009, P(adult) = 0.0001). In addition, the inhibition of TP5 on the production of IFN-gamma by PBMCs from MG children was lower compared with normal child control. But as compared with normal adult control, the inhibition of TP5 showed no significant difference in MG adults (P(adult) = 0.481). TP5 inhibited the expression of IFN-gamma by CD8+ T cell and CD4+ T cell. CONCLUSION: TP5 can inhibit the response of cellular immune by decreasing the production of IFN-gamma in MG consequence display that the level of IFN-gamma significant decreased with the addition of TP5 and anti-CD3. But after considering the age, the level of IFN-gamma in MG children was no as much inhibited as normal child. TP5 inhibits the expression of IFN-gamma by CD8+ T and CD4+ T cells.

[Thymopentin 5 in treatment of relapse after extended thymectomy: a randomized comparative clinical trial of 135 patients with myasthenia gravis].

OBJECTIVE: To investigate the effect of thymopentin 5 (TP5) combined with immunosuppressive agents in treatment of relapse after extended thymectomy in patients with myasthenia gravis (MG). METHODS: One hundred thirty-five MG patients who were to undergo extended thymectomy, 62 adults and 73 children, were randomly assigned to 2 groups: non-TP5 group (n = 60) treated with intramuscular injection of prednisone + pyridostigmine daily for 3 months as a basic treatment, and TP5 group (n = 73), treated with prednisone + pyridostigmine + TP5 for 3 months. Follow-up was conducted for more than 1 year. RESULTS: The remission rates of children in the TP5 group at different time points were all markedly higher than those in the non-TP5 group, and the remission rates of children in the TP5 group during the period of 2 months to 2 years after thymectomy were all significantly higher (all P < 0.05). And the remission rates of the adults of the TP5 group during the period of 6 months to 2 years after thymectomy were all significantly higher than those of the non-TP5 group (all P < 0.05). In the pediatric cases the withdrawal rate of the TP5 group was significantly higher, and the relapse rate was significantly lower than those of the non-TP5 group. No side effect developed during the follow-up. CONCLUSION: TP5 is effective in reducing relapse and has a higher drug withdrawal rate, especially among children.

[Changes in endothelial cellular adhesion molecule mRNA expressions in the cerebral blood vessels of rats with prestroke condition caused by simulated cold wave].

OBJECTIVE: To study the changes in the mRNA expression of endothelial cellular adhesion molecules in the cerebral blood vessels in rats with prestroke condition caused by simulated cold wave. METHODS: Two-kidney two-clip renovascular hypertension was induced in 48 male SD rats, which were subsequently randomly assigned into cold wave exposure and non-exposed group (n=24). Each group was further divided into 4 sub-groups according to their systolic blood pressure, namely the sham-operated group with blood pressure (BP)<140 mmHg, mild hypertensive group with BP of 160-199 mmHg, moderate hypertensive group with BP of 200-219 mmHg, and severe hypertensive group with BP no less than 220 mmHg. Cold wave exposure was simulated by housing the rats in an artificial climate chamber with 3 cycles of 12 h light at 22 degrees celsius; and 12 h dark at 4 degrees celsius;. The non-exposed group was kept at 22 degrees celsius; throughout the experiment. After the exposure, the rats were sacrificed and the tissues of the frontal lobe were slice into 2.0-mm-thick coronal sections for real-time RT-PCR detection of vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1), and p-selectin mRNA expressions. The 5.0-microm-thick frozen sections from the bregma section underwent in situ hybridization of VCAM-1, ICAM-1, and p-selectin. The other sections were stained with HE to observe the infarct lesions, and the rats with cerebral infraction were excluded from the statistical analysis. RESULTS: In rats with cold wave exposure-induced prestroke condition and BP <220 mmHg, VCAM-1, ICAM-1, and p-selectin mRNA expressions all increased compared with those in the non-exposed group. In rats with BP>or=220 mmHg and cold exposure, the expressions all decreased to some extent compared with those in the non-exposed treatment. In the non-exposed rats, a positive correlation of BP to VCAM-1, ICAM-1, and p-selectin mRNA expressions were noted, and this correlation was also found in cold-wave-exposed rats with BP <220 mmHg; VCAM-1, ICAM-1, and p-selectin mRNA expressions decreased dramatically in the exposed rats with BP >or=220 mmHg compared with those in rats with BP <220 mmHg. CONCLUSION: Persistent and severe hypertension impairs the modulatory function of the cerebral vascular endothelia, which is a prerequisite for the stroke vulnerability. The modulatory function deteriorates as the BP further increases.

Endothelium-targeted transgenic GTP-cyclohydrolase I overexpression inhibits neointima formation in mouse carotid artery.

1. Tetrahydrobiopterin (BH(4)) is an essential cofactor that maintains the normal function of endothelial nitric oxide (NO) synthase. Restenosis is a key complication after transluminal angioplasty. Guanosine 5'-triphosphate-cyclohydrolase I (GTPCH) is the first rate-limiting enzyme for de novo BH(4) synthesis. However, the role of GTPCH in restenosis is not fully understood. The present study tested the hypothesis that endothelial-targeted GTPCH overexpression retards neointimal formation, a hallmark of restenosis, in mouse carotid artery. 2. Transluminal wire injury was induced in the left carotid arteries of adult male wild-type C57BL/6 (WT) and endothelial GTPCH transgenic (Tg-GCH) mice. Re-endothelialization was confirmed with in vivo Evans blue staining. Endothelium-dependent and -independent relaxations were measured using isometric tension recording. Morphological analysis was performed 2 and 4 weeks after carotid injury to assess neointimal formation. Fluorescence-based high-performance liquid chromatography (HPLC) was used to determine GTPCH activity and BH(4) levels. Basal NO release following carotid injury was assessed by N(G)-nitro-L-arginine methyl ester-induced vascular contraction. 3. The endothelium was completely removed upon transluminal wire injury and full re-endothelialization was achieved at Day 10. Endothelium-dependent relaxation was impaired 10 days and 4 weeks after carotid injury, whereas endothelium-independent relaxation remained unaffected. Morphological analysis revealed that the endothelial-specific overexpression of GTPCH reduced neointimal formation and medial hypertrophy 2 and 4 weeks after carotid injury. Both arterial GTPCH enzyme activity and BH(4) levels were significantly elevated in Tg-GCH mice compared with WT mice and basal NO release of the injured carotid artery tended to increase in Tg-GCH mice. 4. These findings suggest that the endothelial overexpression of GTPCH increased endothelial BH(4) synthesis and played a preventive role in neointimal formation induced by endothelium denudation.

dl-3n-butylphthalide prevents stroke via improvement of cerebral microvessels in RHRSP.

The purpose of the study is to establish a model of cold-induced stroke in hypertensive rats, and to study the preventive effect of dl-3n-butylphthalide ( NBP ) on stroke. Stroke-prone renovascular hypertension(RHRSP) was created in Sprague-Dawley rats. The animals were assigned randomly to NBP, aspirin treated and vehicle control group, with administration of the medications for 7 days, and then subjected to cold treatment in an environmentally controlled chamber for 3 days to induce the occurrence of stroke. The incidence of stroke, the volume of the brain lesion, patency of the microvessels by FITC-dextran perfusion and the number of microvessels by immunohisochemical detection of vwF were investigated. Cold induced different types of stroke in RHRSP. The incidence of ischemic stroke and the volume of the infarct were decreased, and the perfused microvessels were increased with NBP pretreatment. Our data suggest that NBP prevents cold-induced ischemic stroke via improvement of cerebral microvessels.