Clinical features and underlying causes of cerebral venous thrombosis in Japanese patients

Protein S-Leu17Pro disrupts the hydrophobicity of its signal peptide causing a proteasome-dependent degradation

INTRODUCTION

Protein S is a vitamin K-dependent glycoprotein with important anticoagulant, fibrinolytic, anti-inflammatory, anti-apoptotic, and cytoprotective functions. Congenital protein S deficiency is an autosomal dominant thrombophilia due to protein S gene (PROS1) variations. Our group identified a variation in PROS1 that translates into protein S deficiency: c.50 T > C (p.Leu17Pro). Here, we investigated the mechanisms by which this variation results in protein S deficiency.

MATERIALS AND METHODS

The effect of L17P substitution on protein S signal peptide was predicted by in silico (a computational prediction technique) analysis of hydrophobicity and signal peptide cleavage. Recombinant protein S was overexpressed in HEK293 and COS-7 cells. Intracellular kinetics and extracellular secretion of recombinant protein S-L17P were analyzed by western blotting and immunocytochemistry.

RESULTS

In silico hydrophobicity analysis showed that protein S-L17P had disrupted hydrophobic status in the h-region of its signal peptide. Under normal culture conditions, recombinant protein S -L17P was not detected in either transfectant cell lysates or medium. Upon treatment with a proteasome inhibitor, recombinant protein S-L17P was clearly detected in the cell lysate, but not in the culture medium. Recombinant protein S-L17P did not undergo post-translational modification with N-glycosylation, suggesting that the nascent polypeptide of recombinant protein S-L17P is not transported to the endoplasmic reticulum lumen, but is mislocalized to the cytosol.

CONCLUSION

PROS1-L17P variation translates into protein S deficiency. Protein S-L17P causes its cytosolic mislocalization resulting in its proteasome-dependent degradation.

Seizure in cerebral venous and sinus thrombosis

Many conflicting issues exist about seizure in the setting of cerebral venous and sinus thrombosis (CVST). In this article we aimed to address the existing data regarding incidence, characteristics, predictors, treatment, and prognosis of acute and late seizures in patients with CVST and to prepare more practical information for clinicians. PubMed, Embase, Web of science and Cochrane databases were searched within 1966–2016 using relevant keywords. A total of 63 papers met the inclusion criteria. Seizures are classified as acute symptomatic seizures (ASS; first 14 days) and post‐CVST epilepsy (PCE; after 14 days). The incidence had been reported in a wide range of 6.9–76% for ASS and 4–16% for PCE. Focal and generalized seizures were observed with different predominance. ASS commonly occurred in patients with loss of consciousness, focal neurological deficits, supratentorial lesions and thrombosis in superior sagittal sinus, straight sinus, and cortical veins. PCE had been predisposed by occurrence of ASS, motor deficit, and supratentorial lesions, particularly hemorrhage. Most experts believe that primary prophylaxis with antiepileptic drugs in the acute phase is not indicated. However, the initiation of prophylaxis after the first seizure in patients with supratentorial lesions or focal neurological deficit should be recommended. The quality of current evidence is low and most conclusions are based on expert opinions. More accurate reports of seizure semiology, detailed antiepileptic treatment plans, and outcomes are necessary to answer the existing questions.

Congenital Thrombophilia in Patients With Superior Mesenteric Venous Thrombosis or Portal Vein Thrombosis

We explored the relationship between abdominal vein thromboses, including portal vein thrombosis (PVT) and superior mesenteric vein thrombosis (SMVT), and thrombophilia. The frequency of thrombophilia, such as antithrombin (AT), protein C (PC), or protein S (PS) gene mutations, was examined in 21 patients with PVT, 6 patients with SMVT, and 6 patients with both PVT and SMVT. Low levels of AT, PC, or PS were frequently detected in patients with PVT or mesenteric vein thrombosis, and 4 mutations in the PS gene, 3 mutations in the PC gene, and 2 mutations in AT the gene were detected. Protein S Tokushima was detected in 3 of 4 patients with a PS gene mutation and was associated with 2 other PS gene mutations. The onset of PVT or SMVT was almost idiopathic in patients with congenital thrombophilia. Both PVT and SMVT were frequently caused by an AT, a PC, or a PS mutation, and the onset of these thromboses due to thrombophilia was frequently idiopathic.

A Multicenter Study of 1144 Patients with Cerebral Venous Thrombosis: The VENOST Study

BACKGROUND

Based on a number of small observational studies, cerebral venous sinus thrombosis has diverse clinical and imaging features, risk factors, and variable outcome. In a large, multicenter cerebral venous thrombosis (VENOST) study, we sought to more precisely characterize the clinical characteristics of Caucasian patients.

METHODS

All data for the VENOST study were collected between the years 2000 and 2015 from the clinical follow-up files. Clinical and radiological characteristics, risk factors, and outcomes were compared in terms of age and sex distribution.

RESULTS

Among 1144 patients 68% were women, and in older age group (>50 years) male patients were more prevalent (16.6% versus 27.8%). The most frequent symptoms were headache (89.4%) and visual field defects (28.9%) in men, and headache (86.1%) and epileptic seizures (26.8%) in women. Gynecological factors comprised the largest group in women, in particular puerperium (18.3%). Prothrombotic conditions (26.4%), mainly methylenetetrahydrofolate reductase mutation (6.3%) and Factor V Leiden mutation (5.1%), were the most common etiologies in both genders. 8.1% of patients had infection-associated and 5.2% had malignancy-related etiology that was significantly higher in men and older age group. Parenchymal involvement constitutively hemorrhagic infarcts, malignancy, and older age was associated with higher Rankin score. Epileptic seizures had no effect on prognosis.

CONCLUSIONS

Clinical and radiological findings were consistent with previous larger studies but predisposing factors were different with a higher incidence of puerperium. Oral contraceptive use was not a prevalent risk factor in our cohort. Malignancy, older age, and hemorrhagic infarcts had worse outcome.

Cerebral venous sinus thrombosis in the patient with multiple sclerosis associated with congenital antithrombin deficiency

We report the case of a 25-year-old man with multiple sclerosis (MS) who had severe headache and unconsciousness. He suffered from optic neuritis that had started at age 6. From the age of 12 years, he had suffered from multiple sclerosis (MS) cerebral lesions that relapsed three times over for 5 years. At age 25, he showed a new lesion in the cerebellar cortex, suggesting an exacerbation of the MS. However, magnetic resonance imaging findings the next day showed cerebral venous sinus thrombosis. His laboratory findings showed low antithrombin activity. Genetic analysis revealed a single-base substitution (C>T) at the codon 359 (Arg to STOP) in the 5th exon portion of the antithrombin gene, heterozygote. In the literature review, 17 cases of multiple sclerosis associated with cerebral venous sinus thrombosis, which occurred after the lumbar puncture and the treatment with high-dose methylpredonisolone in 11 of these cases. In our case, antithrombin deficiency, hyperhomocystinemia, infection, and lumbar puncture were suggested as the risk factors.

Comparison of three different anti-Xa assays in major orthopedic surgery patients treated with fondaparinux

Anti-Xa assays are useful for monitoring the effects of selective anti-Xa drugs, such as fondaparinux, in the prophylaxis of deep vein thrombosis. In the present study, anti-Xa activity was measured using three different assays, Testzym(®) Heparin S, STA(®)-Liquid Anti-Xa and HemosIL(®) Liquid Heparin. Anti-Xa activity in each assay gradually increased from day one after administration to day eight, and still remained on day 15. Although there were significant differences in anti-Xa activity among the three assays, the activity showed significant correlation across assays. There were no significant differences in the anti-Xa activity between patients with and without DVT or between patients with and without massive bleeding on day one before and after administration, day four, day eight and day 15. Anti-Xa activity in each assay was weakly correlated with antithrombin (AT) activity. The AT activity in patients were significantly higher on days four, eight and 15 compared with day one before and after administration, suggesting that AT activity increases following the administration of fondaparinux. The three anti-Xa assay kits tested are useful for monitoring fondaparinux treatment in orthopedic surgery patients.