Systematic Mendelian Randomization Exploring Druggable Genes for Hemorrhagic Strokes.

Patients with hemorrhagic stroke have high rates of morbidity and mortality, and drugs for prevention are very limited. Mendelian randomization (MR) analysis can increase the success rate of drug development by providing genetic evidence. Previous MR analyses only analyzed the role of individual drug target genes in hemorrhagic stroke; therefore, we used MR analysis to systematically explore the druggable genes for hemorrhagic stroke. We sequentially performed summary-data-based MR analysis and two-sample MR analysis to assess the associations of all genes within the database with intracranial aneurysm, intracerebral hemorrhage, and their subtypes. Validated genes were further analyzed by colocalization. Only genes that were positive in all three analyses and were druggable were considered desirable genes. We also explored the mediators of genes affecting hemorrhagic stroke incidence. Finally, the associations of druggable genes with other cardiovascular diseases were analyzed to assess potential side effects. We identified 56 genes that significantly affected hemorrhagic stroke incidence. Moreover, TNFSF12, SLC22A4, SPARC, KL, RELT, and ADORA3 were found to be druggable. The inhibition of TNFSF12, SLC22A4, and SPARC can reduce the risk of intracranial aneurysm, subarachnoid hemorrhage, and intracerebral hemorrhage. Gene-induced hypertension may be a potential mechanism by which these genes cause hemorrhagic stroke. We also found that blocking these genes may cause side effects, such as ischemic stroke and its subtypes. Our study revealed that six druggable genes were associated with hemorrhagic stroke, and the inhibition of TNFSF12, SLC22A4, and SPARC had preventive effects against hemorrhagic strokes.

Clinical outcomes and predictive model of platelet reactivity to clopidogrel after acute ischemic vascular events.

BACKGROUND: High on-treatment platelet reactivity (HTPR) has been suggested as a risk factor for patients with ischemic vascular disease. We explored a predictive model of platelet reactivity to clopidogrel and the relationship with clinical outcomes. METHODS: A total of 441 patients were included. Platelet reactivity was measured by light transmittance aggregometry after receiving dual antiplatelet therapy. HTPR was defined by the consensus cutoff of maximal platelet aggregation >46% by light transmittance aggregometry. CYP2C19 loss-of-function polymorphisms were identified by DNA microarray analysis. The data were compared by binary logistic regression to find the risk factors. The primary endpoint was major adverse clinical events (MACEs), and patients were followed for a median time of 29 months. Survival curves were constructed with Kaplan-Meier estimates and compared by log-rank tests between the patients with HTPR and non-HTPR. RESULTS: The rate of HTPR was 17.2%. Logistic regression identified the following predictors of HTPR: age, therapy regimen, body mass index, diabetes history, CYP2C192, or CYP2C193 variant. The area under the curve of receiver operating characteristic for the HTPR predictive model was 0.793 (95% confidence interval: 0.738-0.848). Kaplan-Meier analysis showed that patients with HTPR had a higher incidence of MACE than those with non-HTPR (21.1% vs. 9.9%; χ = 7.572, P = 0.010). CONCLUSIONS: Our results suggest that advanced age, higher body mass index, treatment with regular dual antiplatelet therapy, diabetes, and CYP2C192 or CYP2C193 carriers are significantly associated with HTPR to clopidogrel. The predictive model of HTPR has useful discrimination and good calibration and may predict long-term MACE.

Analysis of the Expression of Angioarchitecture-related Factors in Patients with Cerebral Arteriovenous Malformation.

BACKGROUND: Cerebral arteriovenous malformation (cAVM) is a type of vascular malformation associated with vascular remodeling, hemodynamic imbalance, and inflammation. We detected four angioarchitecture-related cytokines to make a better understanding of the potential aberrant signaling in the pathogenesis of cAVM and found useful proteins in predicting the risk of cerebral hemorrhage. METHODS: Immunohistochemical analysis was conducted on specimens from twenty patients with cAVM diagnosed via magnetic resonance imaging and digital subtraction angiography and twenty primary epilepsy controls using antibodies against vascular endothelial growth factor receptor-2 (VEGFR-2), matrix metalloproteinase-9 (MMP-9), vascular cell adhesion molecule (VCAM-1), and endothelial nitric oxide synthase (eNOS). Western blotting and real-time fluorescent quantitative polymerase chain reaction (PCR) were performed to determine protein and mRNA expression levels. Student's t-test was used for statistical analysis. RESULTS: VEGFR-2, MMP-9, VCAM-1, and eNOS expression levels increased in patients with cAVM compared with those in normal cerebral vascular tissue, as determined by immunohistochemical analysis. In addition, Western blotting and real-time PCR showed that the protein and mRNA expression levels of VEGFR-2, MMP-9, VCAM-1, and eNOS were higher in the cAVM group than in the control group, all the differences mentioned were statistically significant (P < 0.05). CONCLUSIONS: VEGFR-2, MMP-9, VCAM-1, and eNOS are upregulated in patients with cAVM and might play important roles in angiogenesis, vascular remodeling, and migration in patients with cAVM. MMP-9, VEGFR-2, VCAM-1, and eNOS might be potential excellent group proteins in predicting the risk of cerebral hemorrhage at arteriovenous malformation.

[Expression of TGFbeta1 and its type I receptors ALK1 and ALK5 mRNA in brain arteriovenous malformation].

OBJECTIVE: To explore the expression of transforming growth factor beta1 (TGFbeta1) and its type I receptors activin-like kinase 1 (ALK1) and ALK5 mRNA in the development of brain arteriovenous malformation (BAVM). METHODS: The mRNA expressions of TGFbeta1, ALK1and ALK5 were detected with semiquantitative RT-PCR in patients with BAVM. RESULTS: The expressions of TGFbeta1 and ALK5 mRNA increased significantly in BAVM, and their relative expression quantity were 0.777-/+0.047 and 0.585-/+0.074, respectively. However, ALK1 mRNA expression declined significantlies with a relative expression of 0.173-/+0.044 in comparison with the control group (0.720-/+0.098, P<0.01). CONCLUSION: The balance of TGFbeta1 and its type I receptors ALK1 and ALK5 mRNA expressions may play important role in the development of BAVM.

[Evaluation of cerebral vasospasm resulting from subarachnoid hemorrhage with 1H-magnetic resonance spectroscopy].

OBJECTIVE: To assess the value of (1)H-magnetic resonance spectroscopy ((1)H-MRS) in evaluating cerebral vasospasm resulting from subarachnoid hemorrhage (SAH). METHODS: Six dogs were subjected to autologous non-heparinized blood injection via cisternal puncture twice at one-day interval to establish models of SAH, and another 6 received injections with normal saline in an identical manner. (1)H-MRS scan was performed on the 3rd, 7th and 14th days after the injections to measure the changes of N-acetylaspartate (NAA), creatine (Cr) and choline (Cho). After the (1)H-MRS scan, all the dogs underwent brain digital subtraction angiography (DSA) for determining the basilar artery diameter. RESULTS: DSA results on day 3 presented development of obvious vasospasm of the basilar artery, which was most evident on day 7 and recovered obviously on day 14. (1)H-MRS results demonstrated obvious changes of NAA, Cho and Cr on days 3 and 7 in SAH model group, and NAA declined to the lowest level on day 3 followed by gradual ascending till reaching the normal level on day 14. Cho decreased slightly on day 3, then increased and reached the peak level on day 7 and then decreased. Cr rose steadily from day 3 to 14, but since day 7, the rise slowed down obviously and Cr maintain a level not significantly different from that on day 14 (P>0.05). The functional results of (1)H-MRS were consistent with the DSA results. CONCLUSION: (1)H-MRS can be used to monitor the development of cerebral vasospasm resulting from SAH as a good evaluation method for functional imaging.

[Digital subtraction angiography and preoperative embolization for meningiomas].

OBJECTIVE: To investigate the diagnostic value of digital subtraction angiography (DSA) and the clinical efficacy of preoperative embolization for miningiomas. METHODS: Fifty-eight patients with meningioma were examined by DSA, and preoperative embolization was performed in patients whose miningiomas were supplied predominantly by the external carotid artery (ECA). RESULTS: In 43 patients, the meningiomas was exclusively or predominantly supplied by ECA, and the feeding arteries were embolized with particles of 250-350 microm through catherization of ECA. The blood supply of the tumor in 31 patients was completely blocked, and partial occlusion through embolization was performed in 12 patients. No complications in relation to the embolization occurred. Fifty-three patients underwent total removal of the meningiomas and the others had partial removal 1-7 days following DSA and embolization, with tumor-associated intraoperative hemorrhage of 600 ml on average. CONCLUSION: DSA has important diagnostic value for meningiomas, and preoperative embolization can be safe and effective to reduce bleeding, shorten the operation time and prevent postoperative complications.

[Mechanism of Ca2+ on the hyperthermia-induced apoptosis of rat hippocampal neurons in vitro].

OBJECTIVE: To study the mechanism of Ca(2+) on the apoptosis induced by hyperthermia in neonate rat hippocampal neurons to provide the applicative evidence of dantrolene for preventing brain injuries. METHODS: Dantrolene, Ca(2+) specific blocking agent, was used in the hyperthermia-induced apoptosis of primary hippocampal neurons in vitro to observe its effect on the apoptosis, fluorescent intensity, and dynamic change of Ca(2+) by flowcytometry and laser confocal microscopy. RESULTS: The rate of apoptosis was decreased significantly after hyperthermia treatment by dantrolene sodium. The intracellular Ca(2+) fluorescent intensity in 42 degrees C treatment group (107.35 +/- 6.0) was significantly lower than that in control group (159.12 +/- 33.8). The concentration of Ca(2+) began to decrease 20 approximately 25 s after adding dantrolene sodium, and reached the lowest level about 50 s later, and then kept lower than the basal level. CONCLUSION: Dantrolene sodium has an important protective effect on hippocampal neurons apoptosis induced by hyperthermia and may have some applicative value of preventing heat-induced brain injury.

[Changes in Ca2+ concentration mediated by N-methyl-D-aspartate receptor in PO/AH neurons of anoxic SD rats].

OBJECTIVE: To study the changes of Ca2+ concentration mediated by N-methyl-D-aspartate (NMDA) receptor in the neurons in the preoptic area/anterior hypothalamus (PO/AH) of anoxic SD rats by investigating the properties of NMDA receptor. METHODS: The effects of NMDA receptor agonist NMDA and antagonist vaproic acid (VPA) on the [Ca2+]i in PO/AH neurons were observed in SD rats with anoxia. RESULTS: Under normal condition, the fluorescencet ratio was 0.95, which increased obviously in response to treatment with NMDA at 40 s and reached the peak value, 2.054, after 25 s with an increment of (109+/-52) %. After the addition of the agonist, the peak value reached 3.783 in 30 s and maintained the high level. The concentration of Ca2+ increased by (286+/-91) % after the treatment with NMDA. While in the anoxia group, the concentration of Ca2+ decreased by (103+/-45)% after the addition of VPA. CONCLUSIONS: The increase in the concentration of Ca2+ results predominantly from the opening of NMDA receptor channel which allows Ca2+ influx. VPA may decrease the activity of NMDA receptor to reduce the Ca2+ concentration for the protection of the neurons against anoxia.

[Effects of combined stress on rabbit serum and gastroduodenal mucosa motilin and its mechanism].

OBJECTIVE: To study the effects of heat exposure and trauma stress on the level of motilin (MTL) in plasma and the distribution of MTL gastroduodenal mucosa and its mechanism in rabbits. METHODS: The rabbits were randomly divided into four groups, control group, trauma group (23 centigrade degree), heat exposure group (38 centigrade degree) and heat exposure combined trauma group. The MTL was measured by radioimmunoassay (RIA). The rabbit model of heat exposure with trauma was established. The levels of the MTL were measured at 0, 0.5, 1, 1.5 and 2 hours during experiment. RESULTS: In control group, the concentration of MTL was highest in gastric corpus, and then were gastric fundus, pylorus and Duodenal mucous membrane. The concentration of MTL was higher in plasma than that in tissues. After heat exposure and trauma, the concentration of MTL decreased in tissues and increased in plasma. CONCLUSION: The concentration of MTL was different in different parts of gastroduodenal mucosa. The heat exposure and trauma stress may result in the converse changes of the level of MTL in plasma and tissues. The mechanism might be that the destroyed Mo cells released MTL and increasing level of bombesin stimulated by stress induced the release of MTL.

[Effect of hyperthermia combined with trauma on serum nitric oxide and mean arterial pressure in rabbits].

OBJECTIVE: To study the early change of serum nitric oxide (NO) after acute heat exposure with trauma and the effect of NO on mean arterial pressure (MAP), thus to provide theoretical basis for studying the mechanism of NO effect in acute stress. METHODS: The rabbit model of acute heat exposure combined with trauma was established. The animals were divided into four groups, including control, trauma, hyperthermia and hyperthermia combined with trauma. The levels of NO were measured at different time points: 0 h, 1 h, 2 h and MAP was monitored throughout the whole experiment. RESULTS: The concentration of NO declined at first and then increased at 1 h or so after acute heat exposure and trauma. The levels of NO in hyperthermia with trauma group at 1 h, 2 h were (42.75 +/- 8.24), (59.54 +/- 9.05) micro mol/L respectively (P < 0.05), while those in control group were (56.63 +/- 3.79) and (55.22 +/- 7.15) micro mol/L, the difference at 1h between two groups was significant (P < 0.05). Under the circumstance of hyperthermia and trauma, the level of MAP declined to the lowest point at 60 - 70 min and then showed a transient rise, after that, the level declined rapidly. CONCLUSIONS: At the early stage of acute heat exposure and trauma, the concentration of serum NO declined at first and then increased, and had certain relationship with the change of MAP.