Amyloid-β₄₂ is associated with cognitive impairment in healthy elderly and subjective cognitive impairment

The aim of this study was to predict cognitive performance on the basis of the cerebrospinal fluid (CSF) biomarkers total tau (T-tau) and amyloid-β?? (Aβ??) in controls and patients at various impairment levels. Previous studies have found an association of CSF T-tau levels with cognitive symptoms, but it has been difficult to relate Aβ to cognition, and it has thus been hypothesized that Aβ reaches a plateau level prior to cognitive symptoms. A comprehensive battery of neuropsychological tests was subjected to factor analysis to yield aggregated cognitive domains. Linear regression models were performed for the total sample of the Gothenburg MCI study (n = 435) and for each level of impairment. Aβ?? and T-tau accounted for a significant proportion of performance in all cognitive domains in the total sample. In controls (n = 60) and patients with subjective cognitive impairment (n = 105), Aβ?? predicted a significant proportion of semantic and working memory performance. For patients with mild cognitive impairment (n = 170), T-tau had the most pronounced impact across cognitive domains, and more specifically on episodic memory, visuospatial, and speed/executive performance. For patients with dementia (n = 100), the most pronounced impacts of Aβ?? were found in episodic memory and visuospatial functioning, while T-tau was substantially associated with episodic memory. Our results suggest that cognition is related to CSF biomarkers regardless of impairment level. Aβ?? is associated with cognitive functions from a potentially early to a later disease phase, and T-tau is more indicative of performance in a later disease phase.     

Apolipoprotein E ε4 is not associated with cognitive impairment in patients with idiopathic REM sleep behavior disorder

We analyzed 136 patients (age, 67.5 ± 6.9 years; men, 59.6%) with idiopathic rapid eye movement sleep behavior disorder (iRBD). The results of the neuropsychological tests were not significantly different between APOE ε4 carriers and noncarriers, suggesting that the APOE ε4 allele was not associated with cognitive impairment in iRBD.     

Adrenergic α2A receptor gene is not associated with methylphenidate response in adults with ADHD

Adrenergic α2A receptor gene (ADRA2A) is one of the most promising candidate genes for ADHD pharmacogenetics. Thus far, three studies have investigated the association between the ADRA2A −1291 C>G polymorphism and the therapeutic response to methylphenidate (MPH) in children with ADHD, all of them with positive results. The aim of this study is to investigate, for the first time, the association between three ADRA2A polymorphisms (−1291 C>G, −262 G>A, and 1780 C>T) and the response to MPH in adults with ADHD. The sample comprises 165 Brazilians of European descent evaluated in the adult ADHD outpatient clinic of the Hospital de Clínicas de Porto Alegre. The diagnostic procedures followed the DSM-IV criteria. Drug response was assessed by both categorical and dimensional approaches, through the scales Swanson, Nolan, and Pelham Rating scale version IV and the Clinical Global Impression-Severity Scale, applied at the beginning and after the 30th day of treatment. We found no evidence of association between the three ADRA2A polymorphisms and the therapeutic response to MPH treatment. Our findings do not support a significant role for the ADRA2A gene in ADHD pharmacogenetics, at least among adult patients.     

IL-4Rα deletion disrupts psychomotor performance and reference memory in mice while sparing behavioural phenotype associated with spatial learning

Contribution of immune mediators, interleukin-4 and interferon gamma to cognitive functioning is receiving increasing attention. However, the fundamental question about how heterodimeric interleukin-4 receptor alpha– and interferon gamma– producing myeloid cells converge to influence hippocampal–dependent spatial memory tasks through immunomodulation of multisensory inputs from other brain areas remains unexplored. Here, we show that mice lacking interleukin-4 receptor alpha are able to successfully learn spatial tasks, while reference memory is impaired. Moreover, the absence of interleukin-4 receptor alpha leads to simultaneous increase in proportions of CD11b + myeloid cells in the hippocampus and thalamus, but not the brainstem during acquisition. Interleukin-4 receptor alpha deletion significantly decreased expression of myeloid cell–derived interferon gamma in the thalamus during the acquisition phase and simultaneously increased brain-derived neurotrophic factor production in the thalamus and brainstem of trained mice. We provide evidence that interleukin-4 receptor alpha is essential for cognitive performance while training–induced alterations in interferon gamma activity and brain-derived neurotrophic factor signalling may contribute to neuromodulation of learned tasks and consequently affect systems–level memory encoding and consolidation.     

Association between TNF-α promoter -308A/G polymorphism and tardive dyskinesiain Chinese Han patients with schizophrenia

Objective

Previous studies have indicated that the immune may be involved in the pathogenesis of tardive dyskinesia (TD). Some genetic polymorphisms in the human leukocyte antigen (HLA) I and II regions have been associated with TD, and the tumor necrosis factor-α (TNF-α) gene is located in the HLA III region. TNF-α levels in the striatum significantly increased in haloperidol-induced TD in rats. The TNF-α gene −308A/G single nucleotide polymorphism (SNP) has been shown to directly influence TNF-α expression. The genetic association between the TNF-α gene −308A/G SNP and TD is unclear. The present study investigated whether this variation is associated with clinical phenotypes and TD in schizophrenia in a genetically homogeneous northern Chinese Han population.

Methods

We genotyped the TNF-α gene −308A/G SNP in patients with schizophrenia with TD (n = 350) and without TD (n = 410). The Abnormal Involuntary Movement Scale (AIMS) and Positive and Negative Syndrome Scale (PANSS) were used to assess the severity of TD and psychopathology of schizophrenia, respectively.

Results

The allele and genotype frequencies did not significantly differ between patients with schizophrenia with and without TD (p > 0.05). No significant difference was found in the total AIMS score between the genotypes (p > 0.05). However, the PANSS negative symptom subscore was associated with risk for TD (p = 0.004), and a significant difference was found in total AIMS score between the genotypes in TD patients (p = 0.013).

Conclusion

The TNF-α gene −308A/G polymorphism does not appear to play a major role in the susceptibility to TD in patients with schizophrenia in a northern Chinese Han population. However this polymorphism may play a role in the TD severity.     

Altered visual–spatial attention to task-irrelevant information is associated with falls risk in older adults

Executive cognitive functions play a critical role in falls risk—a pressing health care issue in seniors. In particular, intact attentional processing is integral for safe mobility and navigation. However, the specific contribution of impaired visual–spatial attention in falls remains unclear. In this study, we examined the association between visual–spatial attention to task-irrelevant stimuli and falls risk in community-dwelling older adults. Participants completed a visual target discrimination task at fixation while task-irrelevant probes were presented in both visual fields. We assessed attention to left and right peripheral probes using event-related potentials (ERPs). Falls risk was determined using the valid and reliable Physiological Profile Assessment (PPA). We found a significantly positive association between reduced attentional facilitation, as measured by the N1 ERP component, and falls risk. This relationship was specific to probes presented in the left visual field and measured at ipsilateral electrode sites. Our results suggest that fallers exhibit reduced attention to the left side of visual space and provide evidence that impaired right hemispheric function and/or structure may contribute to falls.     

REM sleep without atonia is associated with increased rigidity in patients with mild to moderate Parkinson’s disease

ObjectiveIncreased muscle activity during rapid eye movement (REM) sleep (i.e. REM sleep without atonia) is common in people with Parkinson’s disease (PD). This study tested the hypotheses that people with PD and REM sleep without atonia (RSWA) would present with more severe and symmetric rigidity compared to individuals with PD without RSWA and age-matched controls.MethodsSixty-one individuals participated in this study (41 PD, 20 controls). An overnight sleep study was used to classify participants with PD as having either elevated (PD-RSWA+) or normal muscle activity (PD-RSWA−) during REM sleep. Quantitative measures of rigidity were obtained using a robotic manipulandum that passively pronated and supinated the forearm.ResultsQuantitative measures of forearm rigidity were significantly higher in the PD-RSWA+ group compared to the control group. Rigidity was significantly more asymmetric between limbs in the PD-RSWA− group compared with controls, while there was no significant difference in symmetry between the control and PD-RSWA+ groups.ConclusionIn people with mild to moderate PD, RSWA is associated with an increased and more symmetric presentation of upper limb rigidity.SignificanceDysfunction of brainstem systems that control muscle tone during REM sleep may contribute to increased rigidity during wakefulness in people with PD.     

Cognitive impairment in Parkinson's disease is associated with Default Mode Network subsystem connectivity and cerebrospinal fluid Aβ

IntroductionTo identify clinically implementable biomarkers of cognitive impairment in Parkinson's Disease (PD) derived from resting state-functional MRI (rs-fMRI) and CSF protein analysis.MethodsIn this single-center longitudinal cohort study, we analyzed rs-fMRI and CSF biomarkers from 50 PD patients (23 cognitively normal, 18 mild cognitive impairment, 9 dementia) and 19 controls, who completed comprehensive neuropsychological testing. A subgroup of participants returned for follow-up cognitive assessments three years later. From rs-fMRI, we studied the connectivity within two distinct Default Mode Network subsystems: left-to-right hippocampus (LHC-RHC) and medial prefrontal cortex-to-posterior cingulate cortex (mPFC-PCC). We used regression analyses to determine whether imaging (LHC-RHC, mPFC-PCC), clinical (CSF Aβ-42:40, disease duration), and demographic (age, sex, education) variables were associated with global and domain-specific cognitive impairments.ResultsLHC-RHC (F_3,67 = 3.41,p=0.023) and CSF Aβ-42:40 (χ²(3) = 8.77,p = 0.033) were reduced across more cognitively impaired PD groups. Notably, LHC-RHC connectivity was significantly associated with all global and domain-specific cognitive impairments (attention/executive, episodic memory, visuospatial, and language) at the baseline visit. In an exploratory longitudinal analysis, mPFC-PCC was associated with future global and episodic memory impairment.ConclusionWe used biomarker techniques that are readily available in clinical and research facilities to shed light on the pathophysiologic basis of cognitive impairment in PD. Our findings suggest that there is a functionally distinct role of the hippocampal subsystem within the DMN resting state network, and that intrinsic connectivity between the hippocampi is critically related to a broad range of cognitive functions in PD.     

Gene polymorphism at position –308 of the tumor necrosis factor α promotor is not associated with disease progression in multiple sclerosis patients

Tumor necrosis factor-α (TNFα) is a pluripotent proinflammatory cytokine and is thought to play an important role in the inflammatory process of multiple sclerosis (MS). A G→A transition in the TNFα promotor at position –308 (TNF2 allele) has been shown to be associated with increased TNFα production. This study was designed to detect wether the TNF2 allele is associated with disease progression in MS. We examined the TNFα–308 polymorphism with an allelic discrimination PCR to detect the G→A transition in the genomic DNA of 283 MS patients from Germany and in 72 patients with amyotrophic lateral sclerosis (ALS) and 66 with stroke from the same genetic background who served as controls. Disease severity was defined by the progression index (PI) and by progression to the important clinical landmarks of Extended Disability Status Score (EDSS) 3.5 and 6. In addition, we evaluated the TNFα mRNA expression in whole blood with quantitative PCR. No differences were found between the presence of the TNF2 allele in MS, ALS, or stroke patients. Among the MS patients the TNF2 allele was not associated with a certain disease course. No association was found between the accumulation of neurological deficits and progression to clinical landmarks. Although MS patients with the TNF2 allele tended to progress more rapidly from EDSS 3.5 to EDSS 6 this difference was nonsignificant (P = 0.2). Nevertheless, we observed significantly higher TNFα mRNA expression in blood cells of stable patients carrying the TNF2-allele in comparison to the group with the wild type (P = 0.024). To examine the effect of genetic background we examined the DNA of 60 MS patients and 20 healthy controls in a Cypriot population of Greek origin. There was a significantly lower frequency of the TNF2 allele in the Cyprus population than in Germans (P = 0.01). No significant differences were found between the frequencies of the TNF2 allele in Cypriot MS patients and controls. Although the TNF2 allele is associated with higher TNFα mRNA baseline levels, our data indicate that this allele appears not to contribute to MS susceptibility or severity. In addition our data demonstrate that the TNFα–308 polymorphism is segregated differentially in two European populations of different genetic origin. Received: 30 November 1998 Received in revised form: 8 April 1999 Accepted: 13 May 1999     

A proinflammatory diet is associated with inflammatory gene expression among healthy,non-obese adults: Can social ties protect against the risks?

The Western diet, characterized by high intake of saturated fat, sugar, and salt, is associated with elevated inflammation and chronic disease risk. Few studies have investigated molecular mechanisms linking diet and inflammation; however, a small number of randomized controlled trials suggest that consuming an anti-inflammatory diet (i.e., a primarily plant-based diet rich in monounsaturated fat and lean protein) decreases proinflammatory gene expression. The current study investigated the association between everyday diet and proinflammatory gene expression, as well as the extent to which central adiposity and social involvement modulate risk. Participants were healthy middle-aged and older adults (N = 105) who completed a food frequency questionnaire and reported how many close social roles they have. Anthropometric measurements and blood samples also were collected; gene expression data were analyzed from LPS-stimulated peripheral blood mononuclear cells for interleukin (IL)-6, IL-1β, and tumor necrosis factor (TNF)-α. The inflammatory potential of each participant’s diet was calculated using the Dietary Inflammatory Index (DII®). Participants with higher DII® scores, indicating a more proinflammatory diet, had greater IL-6 (b = −0.02, SE = 0.008, p = .01), IL-1β (b = −0.01, SE = 0.006, p = .03), and TNF-α (b = −0.01, SE = 0.005, p = .04) gene expression if they had a smaller sagittal abdominal diameter (SAD); effects were not seen among those with higher SADs. Social involvement served a protective role, such that participants with smaller SADs had greater IL-6 (b = 0.01, SE = 0.004, p = .049) and IL-1β (b = 0.01, SE = 0.003, p = .045) gene expression only if they had less social involvement; there was no effect of diet on gene expression among those who reported greater social participation. Results are the first to demonstrate a link between self-reported diet and proinflammatory gene expression. Importantly, the effect of diet on gene expression depended upon both body fat composition and social participation, both of which have previously been linked directly with proinflammatory gene expression and inflammation.     

DBH*444G/A polymorphism of the dopamine-β-hydroxylase gene is associated with alcoholism but not with severe alcohol withdrawal symptoms

Summary. As the enzyme dopamine-β-hydroxylase (DβH) converts dopamine to norepinephrine and both transmitters seem to be involved in the pathology of alcoholism and severe alcohol withdrawal symptoms, the gene encoding DβH (DBH) was applied to explore the genetic background of alcoholism and severe withdrawal symptoms. 102 healthy control subjects and 208 alcoholics, including 97 patients with a history of mild withdrawal symptoms, 57 with a history of alcohol withdrawal seizure (AWS) and 82 with a history of delirium tremens (DT) were genotyped for the DBH^*444G/A polymorphism revealing a significantly elevated frequency of genotypes carrying the A-allele (p = 0.02; after Bonferroni adjustment for multiple tests) in alcoholics compared to healthy controls. Frequencies of alleles and genotypes of individuals with mild withdrawal symptoms did not differ significantly from those of patients with DT or AWS.     

Reduced production of IFN-γ and LT-α is associated with successful prednisone therapy in patients with acquired hemophilia A: a pilot study

Glucocorticoids (GC) are a standard treatment for acquired hemophilia A (AH). Although the optimal treatment regimen and duration of GC's is unknown, measurement of sub-clinical immune responses may help direct therapeutic decision making. To study the helpfulness of this approach, three male patients diagnosed with AH were treated with prednisone. The therapy resulted in inhibitor elimination in two out of the three individuals. During the treatment, peripheral mononuclear cells were isolated at different time points and stimulated in vitro. The expression of IFN-γ and LT-α were monitored at both the protein and the mRNA levels. The amount of IFN-γ and LT-α were markedly reduced by the time of inhibitor disappearance in the patients responding to GC therapy but remained high in the non-responder until cyclophosphamide was added. This study suggests that the secretion level of IFN-γ and/or LT-α could be a predictive marker of prednisone responsiveness.     

Cerebral arteriostenosis associated with elevated serum-immunoglobulin E level in young adults without risk factors for ischemic stroke: A possible manifestation of cerebral vasculitis?

We report a series of young adults with symptomatic cerebral arteriostenosis characterized by elevated serum immunoglobulin (Ig) E levels. All patients had no definite risk factors for cerebral vascular diseases. The clinical data of 26 young adults (age 18–50 years) with ischemic stroke, characterized only by increased serum IgE levels and without risk factors for cerebral vascular disease, were retrospectively reviewed. Arteriostenosis was surveyed and followed-up by digital subtraction angiography (DSA), and the stenosis rate was estimated using the warfarin–aspirin symptomatic intracranial disease technique. All patients were treated with corticosteroids according to the common strategy for vasculitis. There was no recurrent stroke during follow-up. The mean degree of stenosis before and after treatment was 69.3 ± 29.8% and 47.9 ± 45.1%, respectively. The difference of stenosis rates between initial and follow-up DSA evaluation was significant using a paired samples test (21.31 ± 26.88, 95% confidence interval [CI] 13.58–29.03, t = 5.55, p < 0.001). Kaplan–Meier survival analysis revealed that the 13-month cumulative improved lesion rate was 40.3 ± 8.7%. This remained the same at 18 months. The mean time to lesion improvement was 12.58 ± 0.96 months (95% CI 10.70–14.46) and median time was 13 ± 3.88 months (95% CI 5.39–20.61). To our knowledge, cerebral arteriostenosis with only elevated IgE serum levels has not been reported. Our data showed that corticosteroid treatment can achieve clinical and artery improvement. This suggests that the cerebral arteriostenosis seen in our study might be caused by some specific type of vessel inflammation.     

The CYP1A2 –163C>A polymorphism is associated with clozapine-induced generalized tonic-clonic seizures in Brazilian schizophrenia patients

We evaluated two polymorphisms at CYP1A2 (^?1C and ^?1F) in a sample of 108 European-derived patients with schizophrenia and their influence on the pro-convulsive effect of clozapine. We found the ^?1F/^?1F genotype to be significantly associated with seizures, and no relationship was observed with combinations of ^?1F and ^?1C alleles.