Buntanetap, a Novel Translational Inhibitor of Multiple Neurotoxic Proteins, Proves to Be Safe and Promising in Both Alzheimer's and Parkinson's Patients.

BACKGROUND: Previously we reported the clinical safety and pharmacological activity of buntanetap (known as Posiphen or ANVS401) in healthy volunteers and mild cognitive impaired (MCI) patients (21). The data supported continued clinical evaluation of buntanetap for treating Alzheimer's Disease (AD). Neurodegenerative diseases such as AD and Parkinson's disease (PD) share several pathological manifestations, including increased levels of multiple neurotoxic protein aggregates. Therefore, a treatment strategy that targets toxic species common to both disorders can potentially provide better clinical outcomes than attacking one neurotoxic protein alone. To test this hypothesis, we recently completed a clinical study in early AD and early PD participants and report the data here. OBJECTIVES: We evaluated safety, pharmacokinetics, biomarkers, and efficacy of buntanetap in treating early AD and PD patients. DESIGN: Double-blind, placebo-controlled, multi-center study. SETTING: 13 sites in the US participated in this clinical trial. The registration number is NCT04524351 at ClinicalTrials.gov. PARTICIPANTS: 14 early AD patients and 54 early PD patients. INTERVENTION: AD patients were given either 80mg buntanetap or placebo QD. PD patients were given 5mg, 10mg, 20mg, 40mg, 80mg buntanetap or placebo QD. MEASUREMENTS: Primary endpoint is safety and tolerability; secondary endpoint is pharmacokinetics of buntanetap in plasma; exploratory endpoints are 1) biomarkers in cerebrospinal fluid (CSF) in both AD and PD patients 2) psychometric tests specific for AD (ADAS-Cogs and WAIS coding test) or PD (MDS-UPDRS and WAIS coding test). RESULTS: Buntanetap was safe and well tolerated. Biomarker data indicated a trend in lowering levels of neurotoxic proteins and inflammatory factors and improving axonal integrity and synaptic function in both AD and PD cohorts. Psychometric tests showed statistically significant improvements in ADAS-Cog11 and WAIS coding in AD patients and MDS-UPDRS and WAIS coding in PD patients. CONCLUSIONS: Buntanetap is well tolerated and safe at doses up to 80mg QD in both AD and PD patients. Cmax and AUC increase with dose without evidence for a plateau up to 80mg QD. The drug shows promising evidence in exploratory biomarker and efficacy measures. Further evaluation of buntanetap in larger, longer-term clinical trials for the treatment of AD and PD are warranted.

The cathepsin B inhibitor z-FA-CMK induces cell death in leukemic T cells via oxidative stress.

The cathepsin B inhibitor benzyloxycarbonyl-phenylalanine-alanine-chloromethyl ketone (z-FA-CMK) was recently found to induce apoptosis at low concentrations in Jurkat T cells, while at higher concentrations, the cells die of necrosis. In the present study, we showed that z-FA-CMK readily depletes intracellular glutathione (GSH) with a concomitant increase in reactive oxygen species (ROS) generation. The toxicity of z-FA-CMK in Jurkat T cells was completely abrogated by N-acetylcysteine (NAC), suggesting that the toxicity mediated by z-FA-CMK is due to oxidative stress. We found that L-buthionine sulfoximine (BSO) which depletes intracellular GSH through the inhibition of GSH biosynthesis in Jurkat T cells did not promote ROS increase or induce cell death. However, NAC was still able to block z-FA-CMK toxicity in Jurkat T cells in the presence of BSO, indicating that the protective effect of NAC does not involve GSH biosynthesis. This is further corroborated by the protective effect of the non-metabolically active D-cysteine on z-FA-CMK toxicity. Furthermore, in BSO-treated cells, z-FA-CMK-induced ROS increased which remains unchanged, suggesting that the depletion of GSH and increase in ROS generation mediated by z-FA-CMK may be two separate events. Collectively, our results demonstrated that z-FA-CMK toxicity is mediated by oxidative stress through the increase in ROS generation.

The cathepsin B inhibitor, z-FA-CMK is toxic and readily induced cell death in human T lymphocytes.

The cathepsin B inhibitor, benzyloxycarbonyl-phenylalanine-alanine-chloromethylketone (z-FA-CMK) was found to be toxic and readily induced cell death in the human T cell line, Jurkat, whereas two other analogs benzyloxycarbonyl-phenylalanine-alanine-fluoromethylketone (z-FA-FMK) and benzyloxycarbonyl-phenylalanine-alanine-diazomethylketone (z-FA-DMK) were not toxic. The toxicity of z-FA-CMK requires not only the CMK group, but also the presence of alanine in the P1 position and the benzyloxycarbonyl group at the N-terminal. Dose-response studies showed that lower concentrations of z-FA-CMK induced apoptosis in Jurkat T cells whereas higher concentrations induced necrosis. In z-FA-CMK-induced apoptosis, both initiator caspases (-8 and -9) and effector caspases (-3, -6 and -7) were processed to their respective subunits in Jurkat T cells. However, only the pro-form of the initiator caspases were reduced in z-FA-CMK-induced necrosis and no respective subunits were apparent. The caspase inihibitor benzyloxycarbonyl-valine-alanine-aspartic acid-(O-methyl)-fluoromehylketone (z-VAD-FMK) inhibits apoptosis and caspase processing in Jurkat T cells treated with low concentration of z-FA-CMK but has no effect on z-FA-CMK-induced necrosis and the loss of initiator caspases. This suggests that the loss of initiator caspases in Jurkat T cells during z-FA-CMK-induced necrosis is not a caspase-dependent process. Taken together, we have demonstrated that z-FA-CMK is toxic to Jurkat T cells and induces apoptosis at low concentrations, while at higher concentrations the cells die of necrosis.

Cognitive deficits in children with gelastic seizures and hypothalamic hamartoma.

OBJECTIVE: To characterize the cognitive deficits in children with gelastic seizures and hypothalamic hamartoma and investigate the relationship of seizure severity to cognitive abilities. METHODS: Eight children with gelastic seizures and hypothalamic hamartoma completed a neuropsychological battery of standardized and age-normed tests, including the Woodcock-Johnson Psycho-Educational Battery-Revised: Tests of Cognitive Ability, Peabody Picture Vocabulary Test-III, and initial-letter word fluency measure. RESULTS: All children displayed cognitive deficits, ranging from mild to severe. Gelastic/complex partial seizure severity was correlated with broad cognitive ability standard scores (r = -0.79; r2 = 0.63; (F[1,6] = 10.28; p = 0.018]. Frequency of gelastic/complex partial seizures was also correlated with broad cognitive ability standard scores (r = -0.72; r2 = 0.52; F[1,6] = 6.44; p = 0.044). Significant intracognitive standard score differences were found, with relative weaknesses in long-term retrieval (mean = 64.1; SD = 13.3) and processing speed (mean = 67.7; SD = 21.6) and a relative strength in visual processing (mean = 97.6; SD = 12.8). Performance in visual processing differed from performance in long-term retrieval (p = 0.009) and processing speed (p = 0.029). CONCLUSION: These findings are consistent with cognitive functions and affective/emotional states associated with conduction pathways of the hypothalamus involving cortical association areas and amygdala and hippocampal formation. These abnormalities can account for the prominent deficit found in integrating information in the processing of memories.

Aggression and psychiatric comorbidity in children with hypothalamic hamartomas and their unaffected siblings.

OBJECTIVE: To assess aggression and psychiatric comorbidity in a sample of children with hypothalamic hamartomas and gelastic seizures and to assess psychiatric diagnoses in siblings of study subjects. METHOD: Children with a clinical history of gelastic seizures and hypothalamic hamartomas (n = 12; age range 3-14 years) had diagnoses confirmed by video-EEG and head magnetic resonance imaging. Structured interviews were administered, including the Diagnostic Interview for Children and Adolescents-Revised Parent Form (DICA-R-P), the Test of Broad Cognitive Abilities, and the Vitiello Aggression Scale. Parents were interviewed with the DICA-R-P about each subject and a sibling closest in age without seizures and hypothalamic hamartomas. Patients were seen from 1998 to 2000. RESULTS: Children with gelastic seizures and hypothalamic hamartomas displayed a statistically significant increase in comorbid psychiatric conditions, including oppositional defiant disorder (83.3%) and attention-deficit/hyperactivity disorder (75%). They also exhibited high rates of conduct disorder (33.3%), speech retardation/learning impairment (33.3%), and anxiety and mood disorders (16.7%). Significant rates of aggression were noted, with 58% of the seizure patients meeting criteria for the affective subtype of aggression and 30.5% having the predatory aggression subtype. Affective aggression was significantly more common (p < .05). Unaffected siblings demonstrated low rates of psychiatric pathology on semistructured parental interview and no aggression as measured by the Vitiello Aggression Scale. CONCLUSIONS: Children with hypothalamic hamartomas and gelastic seizures had high rates of psychiatric comorbidity and aggression. Parents reported that healthy siblings had very low rates of psychiatric pathology and aggression.

Postoperative changes in cerebral metabolism in temporal lobe epilepsy.

BACKGROUND: Fludeoxyglucose F 18 positron emission tomography ((18)F-FDG-PET) can detect focal metabolic abnormalities ipsilateral to the seizure focus in 80% of patients with temporal lobe epilepsy (TLE). Regions outside the epileptogenic zone can also be affected. We hypothesized that these remote regions might show altered metabolism, tending to return toward normal values, after surgery. DESIGN: Interictal preoperative and postoperative (18)F-FDG-PET metabolism were compared in patients with refractory TLE. Based on pathological findings, disease was classified in the following 3 groups: mesial temporal sclerosis, mass lesions, and no pathological diagnosis. Quantitative PET data analysis was performed using the region-of-interest template previously described. Global normalization was used to adjust for the effect of antiepileptic medication changes. Data were analyzed by Wilcoxon signed rank test and analysis of variance. SETTING: The Clinical Epilepsy Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health. PATIENTS: Twenty-two patients with refractory TLE. RESULTS: Preoperatively, in all groups, cerebral metabolic rate for glucose was decreased ipsilateral to the resection site in inferior lateral temporal, inferior mesial temporal, and inferior frontal areas and thalamus. Postoperatively, in all groups, cerebral metabolic rate for glucose increased in ipsilateral inferior frontal area and thalamus. In the mesial temporal sclerosis group, we found a statistically significant increase in the contralateral thalamus. CONCLUSION: Temporal lobe epilepsy is associated with extensive preoperative decreased metabolism in inferior lateral temporal, inferior mesial temporal, and inferior frontal areas and thalamus. Postoperatively, we found increased IF and thalamic metabolism. Seizures may have a reversible effect on brain areas connected with, but remote from, the epileptogenic cortex. Arch Neurol. 2000;57:1447-1452

Relationship of seizure frequency to hippocampus volume and metabolism in temporal lobe epilepsy.

PURPOSE: To examine the relationship between frequency of complex partial (CPS) and secondarily generalized tonic-clonic seizures (sGTCS) on hippocampal volume (HV) and temporal lobe metabolism. METHODS: We performed volumetric magnetic resonance imaging (MRI) and positron emission tomography with 18fluorodeoxyglucose (18FDG-PET) in 32 patients with epilepsy. Temporal lobe foci were localized by ictal video-EEG. RESULTS: We did not find any association between CPS frequency or lifetime number of sGTCS and HV or metabolism ipsilateral to electroencephalographic focus. CONCLUSION: The progress of metabolic or pathologic abnormalities of temporal lobe epilepsy may not be altered by adequate seizure control. The presence of an epileptic focus might be associated with progressive neuronal injury even in clinically well-controlled patients.

Intravascular lymphomatosis: contribution of cerebral MRI findings to diagnosis.

Intravascular lymphomatosis (IL) is a rare variant of non-Hodgkin's lymphoma with an unusual predilection for the central nervous system (CNS). Most cases are not diagnosed until postmortem because of variable clinical presentation and nonspecific laboratory findings. Neuroimaging findings vary widely and range from diffuse involvement of the deep white matter to infarct-like lesions. Cerebral magnetic resonance imaging (MRI) may show parenchymal and meningeal gadolinium enhancement. The authors describe brain MRI findings of linear, punctate, and patchy enhancement suggestive of CNS IL in two patients confirmed by brain biopsy/histologic studies. High index of clinical suspicion and careful interpretation of MRI (including gadolinium contrast studies) may contribute to premortem diagnosis and early intervention of this often-missed disease.

Retrospective analysis of surgical treatment outcomes for gelastic seizures: a review of the literature.

Gelastic seizures are known to be refractory to medical treatment and to date surgical therapy has yet to pinpoint the best treatment for these refractory seizures. There has been a multitude of case reports published on gelastic seizures and different surgical treatments, thus we performed a review of the literature on gelastic seizures and surgical treatments to elucidate the best surgical approaches for medically refractory gelastic seizures.

Bilateral hippocampal encephalitis caused by enteroviral infection.

Nonpolio enteroviral encephalitis usually presents as a diffuse, generalized encephalitis. Focal cerebral involvement by nonpolioviruses is uncommon, and neuroradiologic studies in these cases are usually normal. The authors present a case of a 5-year-old male with an acute encephalitic illness and bilateral lesions of the hippocampi on magnetic resonance imaging. Enteroviral nucleic acids were detected in the cerebrospinal fluid by the reverse transcription polymerase chain reaction. The findings suggest that enteroviral infection should be considered in the differential diagnosis of acute bilateral hippocampal encephalitis in patients in whom polymerase chain reaction fails to demonstrate the presence of herpes simplex virus.

The effect of vigabatrin (gamma-vinyl GABA) on cerebral blood flow and metabolism.

OBJECTIVE: To investigate the effect of vigabatrin (VGB; gamma-vinyl gamma-aminobutyric acid [GABA]), a selective irreversible GABA-transaminase inhibitor, on cerebral metabolic rate for glucose (CMRGlc) and cerebral blood flow (CBF) measured with 18F-fluorodeoxyglucose (FDG) PET and 15O water PET. BACKGROUND: Antiepileptic drugs (AEDs) reduce CMRGlc to varying degrees. Phenobarbital causes a mean decrease of 30 to 40%. Phenytoin, carbamazepine (CBZ), and valproate (VPA) cause milder reductions in CMRGlc. The combination of VPA with CBZ results in a greater decrease than either drug alone. The effect of novel AEDs on both CBF and CMRGlc has not been studied extensively. METHODS: Fourteen patients with refractory complex partial seizures on CBZ monotherapy for 4 weeks were included in the study. All patients had baseline 18F-FDG and 15O water PET studies followed by double-blind randomization to placebo (PLC) or VGB while on continuous CBZ treatment. PET scans were repeated after an interval of 2 months on target dose of VGB (50 mg/kg) or PLC. Quantitative PET data analysis was performed using a region of interest template. Significance was tested with the Wilcoxon rank sum test. RESULTS: No statistically significant difference in age, duration of epilepsy, or CBZ levels was observed in the two patient groups. VGB reduced global CMRGlc by 8.1+/-6.5% and global CBF by 13.1+/-10.4%. The change in CMRGlc was different in patients taking VGB compared with those on PLC (p < 0.04). VGB patients showed regional decreases in both CMRGlc and CBF, particularly in temporal lobes. CSF total GABA increased in the VGB patient group (1.48+/-1.06 versus 4.03+/-4.19 nm/mL). The increase differed from the PLC group (p < 0.03). We found a strong relation between decreased total CSF GABA and increased CMRGlc in the VGB patient group (R2 = 0.82, p < 0.01). CONCLUSIONS: Vigabatrin (VGB) causes mild reductions in both cerebral blood flow (CBF) and cerebral metabolic rate for glucose (CMRGlc) in contrast to other drugs such as barbiturates, which are direct agonists at the gamma-aminobutyric acid-benzodiazepine receptor complex. Conventional AEDs depress CBF and CMRGlc to a greater degree than does VGB. The relatively mild reduction could be due to pre- as well as postsynaptic effects or a use-dependent mechanism.