TREM2 variants in neurodegenerative disorders in the Polish population. Homozygosity and compound heterozygosity in FTD patients

Activation of the TREM2 receptor on microglia stimulates phagocytosis and decreases the microglial proinflammatory response. Mutations in exon 2 of the TREM2 gene have been reported to be associated with various neurodegenerative diseases characterized by chronic inflammation. The aim of our study was to evaluate exon 2 of TREM2 gene variants as a putative genetic risk factor for Alzheimer's disease (AD), frontotemporal dementia (FTD), and amyotrophic lateral sclerosis (ALS) in the Polish population. The results were interpreted using previously published data, especially highlighting differences in the prevalence of the variants among Caucasian subpopulations across different geographic regions. The DNA sequence of exon 2 of TREM2 was analyzed in 811 subjects (274 AD, 135 FTD, 194 ALS patients, and 208 neurologically healthy controls). Nine heterozygous variants were detected, including two novel ones: p.G29 = and c.41-2_3insA, found respectively in a control and an ALS patient. Additionally, we identified one homozygous and two compound heterozygous FTD patients. We confirm previous data that homozygous and compound heterozygous TREM2 mutations can be causative for FTD.

Association between Cerebrospinal Fluid Biomarkers for Alzheimer's Disease, APOE Genotypes and Auditory Verbal Learning Task in Subjective Cognitive Decline, Mild Cognitive Impairment, and Alzheimer's Disease

In the course of Alzheimer's disease (AD), early pathological changes in the brain start decades before any clinical manifestation. The concentration levels of AD cerebrospinal fluid (CSF) biomarkers, such as amyloid-β1-42 (Aβ1-42), total tau (T-tau), and phosphorylated tau (P-tau), may reflect a cerebral pathology facilitating an early diagnosis of the disease and predicting a cognitive deterioration. The aim of this study was to estimate the prevalence of AD CSF biomarkers in those individuals with a subjective cognitive decline (SCD), a mild cognitive impairment (MCI), and Alzheimer's dementia (AD-D), together with the relationships between the biomarkers, an APOE ɛ4 presence, and a verbal episodic memory performance. We included 252 patients from the memory clinic with a diagnosis of SCD (n = 85), MCI (n = 87), and AD-D (n = 80). A verbal episodic memory performance level was assessed and was based on a delayed recall trial from the 10-word list of an auditory verbal learning task (AVLT). We found that the patients with more severe cognitive impairments had significantly lower levels of Aβ1-42 and higher levels of T-tau and P-tau. This pattern was also typical for the APOE ɛ4 carriers, who had lower levels of Aβ1-42 than the noncarriers in the AD-D and MCI groups. The levels of T-tau and P-tau were significantly higher in the APOE ɛ4 carriers than in the noncarriers, but only in the MCI patients. The AVLT performance in the whole study samples was predicted by age, Aβ1-42, and the T-tau CSF biomarkers, but not by the APOE genotyping.

Fahr Syndrome - an Important Piece of a Puzzle in the Differential Diagnosis of Many Diseases

Fahr syndrome is a rare neurodegenerative disorder characterized by symmetrical, bilateral calcifications in the basal ganglia, nucleus gyrus and cerebral cortex. The continuous advancement as well as widespread use of brain imaging have contributed to the increasing detection rates of such changes. Nevertheless, their etiology is understood only partially and the methods of causative treatment are limited. Due to various symptoms, Fahr syndrome may resemble diseases from the field of neurology, psychiatry, cardiology and even urology. This article provides an up-to-date review of the literature concerning Fahr syndrome in terms of clinical practice.

Predicting the conversion of mild cognitive impairment to Alzheimer's disease based on the volumetric measurements of the selected brain structures in magnetic resonance imaging

INTRODUCTION

Mild cognitive impairment (MCI) is defined as abnormal cognitive state, but does not meet the criteria for the diagnosis of dementia. According to the new guidelines Alzheimer's disease (AD) involves not only dementia's phase but also predementia phase which is asymptomatic and pathological process in the brain is already present. For this reason it is very important to determine the suitability of markers which should be positive before onset of the first symptoms. One of these biomarkers is a structural magnetic resonance imaging with hippocampal volumetric assessment. The aim of this study was to investigate the usefulness of structural brain magnetic resonance imaging with volumetric assessment of the hippocampus and entorhinal cortex, posterior cingulate gyrus, parahippocampal gyrus, temporal gyri: superior, medial and inferior, to predict the conversion of MCI to AD.

MATERIAL AND METHODS

Magnetic resonance imaging of brain was performed at the baseline visit in 101 patients diagnosed with MCI. Clinic follow-ups were scheduled after 6.12 and 24 months.

RESULTS

Amongst 101 patients with MCI, 17 (16.8%) converted into AD within two years of observation. All measured volumes were lower in converters than non-converters. Discriminant analysis was conducted and sensitivity for MCI conversion to AD was 64.7%, specificity 96.4%. 91% of patients were correctly classified (converter or non-converter).

CONCLUSIONS

Volumetric measurements may help clinicians to predict MCI conversion to AD but due to low sensitivity it cannot be use separately. The study group requires further observation.

A comprehensive study on the contents and leaching of trace elements from fly-ash originating from Polish hard coal by NAA and AAS methods

In order to assess the environmental risks associated with the emission of fly-ash into the atmosphere and its storage on waste heaps, the trace element contents of fly-ashes from burning Polish hard coal were determined by a newly developed INAA method. Leaching of trace elements from the fly-ash by water and H2SO4 solution (pH approximately 2.5) simulating acid rain, respectively, was studied using AAS and spectrophotometric methods. Analogous experiments were done with neutron-irradiated fly-ash, following the composition of the eluate gamma-spectrometrically. The new fine fly-ash (CTA-FFA-1) candidate reference material was prepared, and the certification was undertaken on the basis of an international intercomparison run. Preliminary evaluation of results shows that at least 38 elements will be certified and, in addition, the "information values" for at least 12 elements will be given.