Biomarker Commons

Understanding epileptogenesis in calcified neurocysticercosis with perfusion MRI.

Neurology. 2012 Feb 28;78(9):618-25

Authors: Gupta RK, Awasthi R, Rathore RK, Verma A, Sahoo P, Paliwal VK, Prasad KN, Pandey CM, Narayana PA

Abstract
OBJECTIVES: Calcified cysticercus larva with perilesional abnormality is thought to be responsible for seizures in patients with neurocysticercosis (NCC). However, it is not well understood why some calcified cysts are associated with seizures even without perilesional abnormality.
METHODS: The study group consists of 30 subjects from an ongoing survey for disease burden estimation of a swine farming community who had a single calcified lesion without any perilesional abnormality with or without presentation of seizures. Each group consisted of 15 patients with calcified cysts and was labeled as asymptomatic and symptomatic. We performed dynamic contrast-enhanced (DCE) MRI on all these subjects and determined serum matrix metalloproteinase-9 (MMP-9) levels and MMP-9 gene polymorphisms.
RESULTS: DCE-MRI-derived rate transfer constant (k(ep)) and serum MMP-9 levels showed significant differences between symptomatic and asymptomatic subjects. We observed an increase in the MMP-9 levels, k(ep), and the volume transfer coefficient (k(trans)) in these lesions. We also observed a significant increase in MMP-9 (R279Q) gene polymorphism in symptomatic subjects compared with asymptomatic and control subjects.
CONCLUSIONS: Perilesional inflammation, which varies from symptomatic to asymptomatic subjects, can be quantified using DCE-MRI in calcified cysticercosis and may help distinguish these 2 groups with similar imaging findings. The observed increase in k(ep) with serum MMP-9 levels suggests that the former may serve as a biomarker of MMP-9 levels in these subjects. The significant MMP-9 (R279Q) gene polymorphism in symptomatic subjects might explain the differences in the observed DCE-MRI indices between symptomatic and asymptomatic subjects.

PMID: 22302547 [PubMed - indexed for MEDLINE]

High-frequency oscillations as a new biomarker in epilepsy.

Ann Neurol. 2012 Feb;71(2):169-78

Authors: Zijlmans M, Jiruska P, Zelmann R, Leijten FS, Jefferys JG, Gotman J

Abstract
The discovery that electroencephalography (EEG) contains useful information at frequencies above the traditional 80Hz limit has had a profound impact on our understanding of brain function. In epilepsy, high-frequency oscillations (HFOs, >80Hz) have proven particularly important and useful. This literature review describes the morphology, clinical meaning, and pathophysiology of epileptic HFOs. To record HFOs, the intracranial EEG needs to be sampled at least at 2,000Hz. The oscillatory events can be visualized by applying a high-pass filter and increasing the time and amplitude scales, or EEG time-frequency maps can show the amount of high-frequency activity. HFOs appear excellent markers for the epileptogenic zone. In patients with focal epilepsy who can benefit from surgery, invasive EEG is often required to identify the epileptic cortex, but current information is sometimes inadequate. Removal of brain tissue generating HFOs has been related to better postsurgical outcome than removing the seizure onset zone, indicating that HFOs may mark cortex that needs to be removed to achieve seizure control. The pathophysiology of epileptic HFOs is challenging, probably involving populations of neurons firing asynchronously. They differ from physiological HFOs in not being paced by rhythmic inhibitory activity and in their possible origin from population spikes. Their link to the epileptogenic zone argues that their study will teach us much about the pathophysiology of epileptogenesis and ictogenesis. HFOs show promise for improving surgical outcome and accelerating intracranial EEG investigations. Their potential needs to be assessed by future research.

PMID: 22367988 [PubMed - indexed for MEDLINE]

Homozygous c.14576G>A variant of RNF213 predicts early-onset and severe form of moyamoya disease.

Neurology. 2012 Mar 13;78(11):803-10

Authors: Miyatake S, Miyake N, Touho H, Nishimura-Tadaki A, Kondo Y, Okada I, Tsurusaki Y, Doi H, Sakai H, Saitsu H, Shimojima K, Yamamoto T, Higurashi M, Kawahara N, Kawauchi H, Nagasaka K, Okamoto N, Mori T, Koyano S, Kuroiwa Y, Taguri M, Morita S, Matsubara Y, Kure S, Matsumoto N

Abstract
OBJECTIVE: RNF213 was recently reported as a susceptibility gene for moyamoya disease (MMD). Our aim was to clarify the correlation between the RNF213 genotype and MMD phenotype.
METHODS: The entire coding region of the RNF213 gene was sequenced in 204 patients with MMD, and corresponding variants were checked in 62 pairs of parents, 13 mothers and 4 fathers of the patients, and 283 normal controls. Clinical information was collected. Genotype-phenotype correlations were statistically analyzed.
RESULTS: The c.14576G>A variant was identified in 95.1% of patients with familial MMD, 79.2% of patients with sporadic MMD, and 1.8% of controls, thus confirming its association with MMD, with an odds ratio of 259 and p < 0.001 for either heterozygotes or homozygotes. Homozygous c.14576G>A was observed in 15 patients but not in the controls and unaffected parents. The incidence rate for homozygotes was calculated to be >78%. Homozygotes had a significantly earlier age at onset compared with heterozygotes or wild types (median age at onset 3, 7, and 8 years, respectively). Of homozygotes, 60% were diagnosed with MMD before age 4, and all had infarctions as the first symptom. Infarctions at initial presentation and involvement of posterior cerebral arteries, both known as poor prognostic factors for MMD, were of significantly higher frequency in homozygotes than in heterozygotes and wild types. Variants other than c.14576G>A were not associated with clinical phenotypes.
CONCLUSIONS: The homozygous c.14576G>A variant in RNF213 could be a good DNA biomarker for predicting the severe type of MMD, for which early medical/surgical intervention is recommended, and may provide a better monitoring and prevention strategy.

PMID: 22377813 [PubMed - indexed for MEDLINE]

Predisposition to epilepsy in fragile X syndrome: does the Val66Met polymorphism in the BDNF gene play a role?

Epilepsy Behav. 2011 Nov;22(3):581-3

Authors: Tondo M, Poo P, Naudó M, Ferrando T, Genovés J, Molero M, Martorell L

Abstract
Epilepsy is detected in about 23% of patients with fragile X syndrome (FXS). Absence or reduced levels of the fragile X mental retardation protein (FMRP), a global regulator of translation in neurons and an important factor in synaptic plasticity, produce the observed epileptic patterns. The brain-derived neurotrophic factor (BDNF) gene is a specific regulator of synaptic plasticity, and disturbances in its function cause dendrite abnormalities similar to those observed in FXS. A putative reciprocal regulation of FMRP and BDNF has been hypothesized. The Val66Met polymorphism in the BDNF gene may be involved in the alteration of normal secretion of the mature peptide and may modulate the epileptic phenotype observed in some patients with FXS. We investigated the relationship of this Met66 allele to the prevalence of epilepsy in 77 patients with FXS. No association was observed between this polymorphism and epilepsy in our group of patients. Therefore, it should not be considered a biomarker for developing epilepsy in patients with FXS.

PMID: 21890420 [PubMed - indexed for MEDLINE]

Gelsolin in cerebrospinal fluid as a potential biomarker of epilepsy.

Neurochem Res. 2011 Dec;36(12):2250-8

Authors: Peng X, Zhang X, Wang L, Zhu Q, Luo J, Wang W, Wang X

Abstract
Gelsolin is an actin regulatory protein that generally distributed in a wide variety of body tissues, especially the brain tissues and cerebrospinal fluid. In this study we found that lumbar CSF-gelsolin concentrations markedly decreased in epileptic patients by enzyme linked immunosorbent assay. In order to help judge the result, we determined gelsolin expression in temporal lobe tissues of patients with temporal lobe epilepsy using double-label immunofluorescence to location and using western blot to quantitation. Then we observed that gelsolin was co-expressed with microtubule-associated protein-2 in axons and cytoplasms of neurons and gelsolin protein level was also down-regulated in temporal lobe tissues of epileptic patients. Our findings suggested that CSF-gelsolin level might reflect the alteration of gelsolin in brain tissue of epileptic patients and CSF-gelsolin seems to be a potential biomarker for epilepsy.

PMID: 21786170 [PubMed - indexed for MEDLINE]

A comparison between detectors of high frequency oscillations.

Clin Neurophysiol. 2012 Jan;123(1):106-16

Authors: Zelmann R, Mari F, Jacobs J, Zijlmans M, Dubeau F, Gotman J

Abstract
OBJECTIVE: High frequency oscillations (HFOs) are a biomarker of epileptogenicity. Visual marking of HFOs is highly time-consuming and inevitably subjective, making automatic detection necessary. We compare four existing detectors on the same dataset.
METHODS: HFOs and baselines were identified by experienced reviewers in intracerebral EEGs from 20 patients. A new feature of our detector to deal with channels where baseline cannot be found is presented. The original and an optimal configuration are implemented. Receiver operator curves, false discovery rate, and channel ranking are used to evaluate performance.
RESULTS: All detectors improve performance with the optimal configuration. Our detector had higher sensitivity, lower false positives than the others, and similar false detections. The main difference in performance was in very active channels.
CONCLUSIONS: Each detector was developed for different recordings and with different aims. Our detector performed better in this dataset, but was developed on data similar to the test data. Moreover, optimizing on a particular data type improves performance in any detector.
SIGNIFICANCE: Automatic HFO detection is crucial to propel their clinical use as biomarkers of epileptogenic tissue. Comparing detectors on a single dataset is important to analyze their performance and to emphasize the issues involved in validation.

PMID: 21763191 [PubMed - indexed for MEDLINE]

Identification of a novel biomarker candidate, a 4.8-kDa peptide fragment from a neurosecretory protein VGF precursor, by proteomic analysis of cerebrospinal fluid from children with acute encephalopathy using SELDI-TOF-MS.

BMC Neurol. 2011;11:101

Authors: Asano T, Koizumi S, Takagi A, Hatori T, Kuwabara K, Fujino O, Fukunaga Y

Abstract
BACKGROUND: Acute encephalopathy includes rapid deterioration and has a poor prognosis. Early intervention is essential to prevent progression of the disease and subsequent neurologic complications. However, in the acute period, true encephalopathy cannot easily be differentiated from febrile seizures, especially febrile seizures of the complex type. Thus, an early diagnostic marker has been sought in order to enable early intervention. The purpose of this study was to identify a novel marker candidate protein differentially expressed in the cerebrospinal fluid (CSF) of children with encephalopathy using proteomic analysis.
METHODS: For detection of biomarkers, CSF samples were obtained from 13 children with acute encephalopathy and 42 children with febrile seizure. Mass spectral data were generated by surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF MS) technology, which is currently applied in many fields of biological and medical sciences. Diagnosis was made by at least two pediatric neurologists based on the clinical findings and routine examinations. All specimens were collected for diagnostic tests and the remaining portion of the specimens were used for the SELDI-TOF MS investigations.
RESULTS: In experiment 1, CSF from patients with febrile seizures (n = 28), patients with encephalopathy (n = 8) (including influenza encephalopathy (n = 3), encephalopathy due to rotavirus (n = 1), human herpes virus 6 (n = 1)) were used for the SELDI analysis. In experiment 2, SELDI analysis was performed on CSF from a second set of febrile seizure patients (n = 14) and encephalopathy patients (n = 5). We found that the peak with an m/z of 4810 contributed the most to the separation of the two groups. After purification and identification of the 4.8-kDa protein, a 4.8-kDa proteolytic peptide fragment from the neurosecretory protein VGF precursor (VGF4.8) was identified as a novel biomarker for encephalopathy.
CONCLUSIONS: Expression of VGF4.8 has been reported to be decreased in pathologically degenerative changes such as Alzheimer's disease, amyotrophic lateral sclerosis (ALS), frontotemporal dementia, and encephalopathy. Thus, the VGF4.8 peptide might be a novel marker for degenerative brain conditions.

PMID: 21838886 [PubMed - indexed for MEDLINE]