The D2HG product of IDH1 may increase neuronal activity by mimicking the activity of glutamate on the NMDA receptor, and IDH1 gliomas are more likely to cause seizures in patients. This has rapid translational implications for the personalized management of tumor-associated epilepsy, as targeted IDH1 inhibitors may improve antiepileptic therapy in patients with IDH1 gliomas.

We examined the effects of fetal exposure to a wide range of di-(2-ethylhexyl) phthalate (DEHP) doses on fetal, neonatal, and adult testosterone production. Pregnant rats were administered DEHP from Gestational Day (GD) 14 to the day of parturition (Postnatal Day 0). Exposure to between 234 and 1250 mg/kg/day of DEHP resulted in increases in the absolute volumes of Leydig cells per adult testis. Despite this, adult serum testosterone levels were reduced significantly compared to those of controls at all DEHP doses. Organ cultures of testes from GD20 rats exposed in utero to DEHP showed dose-dependent reductions in basal testosterone production. Surprisingly, however, no significant effect of DEHP was found on hCG-induced testosterone production by GD20 testes, suggesting that the inhibition of basal steroidogenesis resulted from the alteration of molecular events upstream of the steroidogenic enzymes. Reduced fetal and adult testosterone production in response to in utero DEHP exposure appeared to be unrelated to changes in testosterone metabolism. In view of the DEHP-induced reductions in adult testosterone levels, a decrease in the expression of steroidogenesis-related genes was anticipated. Surprisingly, however, significant increases were seen in the expression of Cyp11a1, Cy17a1, Star, and Tspo transcripts, suggesting that decreased testosterone production after birth could not be explained by decreases in steroidogenic enzymes as seen at GD20. These changes may reflect an increased number of Leydig cells in adult testes exposed in utero to DEHP rather than increased gene expression in individual Leydig cells, but this remains uncertain. Taken together, these results demonstrate that in utero DEHP exposure exerts both short-term and long-lasting effects on testicular steroidogenesis that might involve distinct molecular targets in fetal and adult Leydig cells.

Mutant isocitrate dehydrogenase 1 (IDH1) is common in gliomas, and produces D-2-hydroxyglutarate (D-2-HG). The full effects of IDH1 mutations on glioma biology and tumor microenvironment are unknown. We analyzed a discovery cohort of 169 World Health Organization (WHO) grade II-IV gliomas, followed by a validation cohort of 148 cases, for IDH1 mutations, intratumoral microthrombi, and venous thromboemboli (VTE). 430 gliomas from The Cancer Genome Atlas were analyzed for mRNAs associated with coagulation, and 95 gliomas in a tissue microarray were assessed for Tissue Factor (TF) protein. In vitro and in vivo assays evaluated platelet aggregation and clotting time in the presence of mutant IDH1 or D-2-HG. VTE occurred in 26–30% of patients with wild-type IDH1 gliomas, but not in patients with mutant IDH1 gliomas (0%). IDH1 mutation status was the most powerful predictive marker for VTE, independent of variables such as GBM diagnosis and prolonged hospital stay. Microthrombi were far less common within mutant IDH1 gliomas regardless of WHO grade (85–90% in wild-type versus 2–6% in mutant), and were an independent predictor of IDH1 wild-type status. Among all 35 coagulation-associated genes, F3 mRNA, encoding TF, showed the strongest inverse relationship with IDH1 mutations. Mutant IDH1 gliomas had F3 gene promoter hypermethylation, with lower TF protein expression. D-2-HG rapidly inhibited platelet aggregation and blood clotting via a novel calcium-dependent, methylation-independent mechanism. Mutant IDH1 glioma engraftment in mice significantly prolonged bleeding time. Our data suggest that mutant IDH1 has potent antithrombotic activity within gliomas and throughout the peripheral circulation. These findings have implications for the pathologic evaluation of gliomas, the effect of altered isocitrate metabolism on tumor microenvironment, and risk assessment of glioma patients for VTE.

OBJECTIVECerebral venous sinus thrombosis (CVST) is a known complication of surgeries near the major dural venous sinuses. While the majority of CVSTs are asymptomatic, severe sinus thromboses can have devastating consequences. The objective of this study was to prospectively evaluate the true incidence and risk factors associated with postoperative CVST and comment on management strategies.METHODSA prospective study of 74 patients who underwent a retrosigmoid, translabyrinthine, or suboccipital approach for posterior fossa tumors, or a supratentorial craniotomy for parasagittal/falcine tumors, was performed. All patients underwent pre- and postoperative imaging to evaluate sinus patency. Demographic, clinical, and operative data were collected. Statistical analysis was performed to identify incidence and risk factors.RESULTSTwenty-four (32.4%) of 74 patients had postoperative MR venograms confirming CVST, and all were asymptomatic. No risk factors, including age (p = 0.352), BMI (p = 0.454), sex (p = 0.955), surgical approach (p = 0.909), length of surgery (p = 0.785), fluid balance (p = 0.943), mannitol use (p = 0.136), tumor type (p = 0.46, p = 0.321), or extent of resection (p = 0.253), were statistically correlated with thrombosis. All patients were treated conservatively, with only 1 patient receiving intravenous fluids. There were no instances of venous infarctions, hemorrhages, or neurological deficits. The rate of CSF leakage was significantly higher in the thrombosis group than in the nonthrombosis group (p = 0.01).CONCLUSIONSThis prospective study shows that the radiographic incidence of postoperative CVST is higher than that previously reported in retrospective studies. In the absence of symptoms, these thromboses can be treated conservatively. While no risk factors were identified, there may be an association between postoperative CVST and CSF leak.

Decreased cochlear CISS signal may indicate a tumor's association with the cochlear neurovascular bundle, influencing endolymph protein concentration and creating an inability to preserve hearing. This important MRI characteristic can influence planning, counseling, and patient selection for vestibular schwannoma treatment.