Neurological, psychiatric, and sleep investigations after treatment of anti-leucine-rich glioma-inactivated protein 1 (LGI1) encephalitis in Spain: a prospective cohort study.

BACKGROUND: Anti-leucine-rich glioma-inactivated protein 1 (LGI1) encephalitis is an autoimmune disorder that can be treated with immunotherapy, but the symptoms that remain after treatment have not been well described. We aimed to characterise the clinical features of patients with anti-LGI1 encephalitis for 1 year starting within the first year after initial immunotherapy. METHODS: For this prospective cohort study, we recruited patients with anti-LGI1 encephalitis as soon as possible after they had received conventional immunotherapy for initial symptoms; patients were recruited from 21 hospitals in Spain. Patients were excluded if they had an interval of more than 1 year since initial immunotherapy, had pre-existing neurodegenerative or psychiatric disorders, or were unable to travel to Hospital Clínic de Barcelona (Barcelona, Spain). Patients visited Hospital Clínic de Barcelona on three occasions-the first at study entry (visit 1), the second 6 months later (visit 2), and the third 12 months after the initial visit (visit 3). They underwent neuropsychiatric and videopolysomnography assessments at each visit. Healthy participants who were matched for age and sex and recruited from Hospital Clínic de Barcelona underwent the same investigations at study entry and at 12 months. Cross-sectional comparisons of clinical features between groups were done with conditional logistic regression, and binary logistic regression was used to assess associations between cognitive outcomes at 12 months and clinical features before initial immunotherapy and at study entry. FINDINGS: Between May 1, 2019, and Sept 30, 2022, 42 participants agreed to be included in this study. 24 (57%) participants had anti-LGI1 encephalitis (mean age 63 years [SD 12]; 13 [54%] were female and 11 [46%] were male) and 18 (43%) were healthy individuals (mean age 62 years [10]; 11 [61%] were female and seven [39%] were male). At visit 1 (median 88 days [IQR 67-155] from initiation of immunotherapy), all 24 patients had one or more symptoms; 20 (83%) patients had cognitive deficits, 20 (83%) had psychiatric symptoms, 14 (58%) had insomnia, 12 (50%) had rapid eye movement (REM)-sleep behaviour disorder, nine (38%) had faciobrachial dystonic seizures, and seven (29%) had focal onset seizures. Faciobrachial dystonic seizures were unnoticed in four (17%) of 24 patients and focal onset seizures were unnoticed in five (21%) patients. At visit 1, videopolysomnography showed that 19 (79%) patients, but no healthy participants, had disrupted sleep structure (p=0·013); 15 (63%) patients and four (22%) healthy participants had excessive fragmentary myoclonus (p=0·039), and nine (38%) patients, but no healthy participants, had myokymic discharges (p=0·0051). These clinical and videopolysomnographic features led to additional immunotherapy in 15 (63%) of 24 patients, which resulted in improvement of these features in all 15 individuals. However, at visit 3, 13 (65%) of 20 patients continued to have cognitive deficits. Persistent cognitive deficits at visit 3 were associated with no use of rituximab before visit 1 (odds ratio [OR] 4·0, 95% CI 1·5-10·7; p=0·0015), REM sleep without atonia at visit 1 (2·2, 1·2-4·2; p=0·043), and presence of LGI1 antibodies in serum at visit 1 (11·0, 1·1-106·4; p=0·038). INTERPRETATION: Unsuspected but ongoing clinical and videopolysomnography alterations are common in patients with anti-LGI1 encephalitis during the first year or more after initial immunotherapy. Recognising these alterations is important as they are treatable, can be used as outcome measures in clinical trials, and might influence cognitive outcome. FUNDING: Fundació La Caixa.

Leveraging large multi-center cohorts of Alzheimer disease endophenotypes to understand the role of Klotho heterozygosity on disease risk.

Two genetic variants in strong linkage disequilibrium (rs9536314 and rs9527025) in the Klotho (KL) gene, encoding a transmembrane protein, implicated in longevity and associated with brain resilience during normal aging, were recently shown to be associated with Alzheimer disease (AD) risk in cognitively normal participants who are APOE ε4 carriers. Specifically, the participants heterozygous for this variant (KL-SVHET+) showed lower risk of developing AD. Furthermore, a neuroprotective effect of KL-VSHET+ has been suggested against amyloid burden for cognitively normal participants, potentially mediated via the regulation of redox pathways. However, inconsistent associations and a smaller sample size of existing studies pose significant hurdles in drawing definitive conclusions. Here, we performed a well-powered association analysis between KL-VSHET+ and five different AD endophenotypes; brain amyloidosis measured by positron emission tomography (PET) scans (n = 5,541) or cerebrospinal fluid Aß42 levels (CSF; n = 5,093), as well as biomarkers associated with tau pathology: the CSF Tau (n = 5,127), phosphorylated Tau (pTau181; n = 4,778) and inflammation: CSF soluble triggering receptor expressed on myeloid cells 2 (sTREM2; n = 2,123) levels. Our results found nominally significant associations of KL-VSHET+ status with biomarkers for brain amyloidosis (e.g., CSF Aß positivity; odds ratio [OR] = 0.67 [95% CI, 0.55-0.78], ß = 0.72, p = 0.007) and tau pathology (e.g., biomarker positivity for CSF Tau; OR = 0.39 [95% CI, 0.19-0.77], ß = -0.94, p = 0.007, and pTau; OR = 0.50 [95% CI, 0.27-0.96], ß = -0.68, p = 0.04) in cognitively normal participants, 60-80 years old, who are APOE e4-carriers. Our work supports previous findings, suggesting that the KL-VSHET+ on an APOE ε4 genotype background may modulate Aß and tau pathology, thereby lowering the intensity of neurodegeneration and incidence of cognitive decline in older controls susceptible to AD.

Characteristics of subjective cognitive decline associated with amyloid positivity.

INTRODUCTION: The evidence for characteristics of persons with subjective cognitive decline (SCD) associated with amyloid positivity is limited. METHODS: In 1640 persons with SCD from 20 Amyloid Biomarker Study cohort, we investigated the associations of SCD-specific characteristics (informant confirmation, domain-specific complaints, concerns, feelings of worse performance) demographics, setting, apolipoprotein E gene (APOE) ε4 carriership, and neuropsychiatric symptoms with amyloid positivity. RESULTS: Between cohorts, amyloid positivity in 70-year-olds varied from 10% to 76%. Only older age, clinical setting, and APOE ε4 carriership showed univariate associations with increased amyloid positivity. After adjusting for these, lower education was also associated with increased amyloid positivity. Only within a research setting, informant-confirmed complaints, memory complaints, attention/concentration complaints, and no depressive symptoms were associated with increased amyloid positivity. Feelings of worse performance were associated with less amyloid positivity at younger ages and more at older ages. DISCUSSION: Next to age, setting, and APOE ε4 carriership, SCD-specific characteristics may facilitate the identification of amyloid-positive individuals.

The MS4A gene cluster is a key modulator of soluble TREM2 and Alzheimer's disease risk.

Soluble triggering receptor expressed on myeloid cells 2 (sTREM2) in cerebrospinal fluid (CSF) has been associated with Alzheimer's disease (AD). TREM2 plays a critical role in microglial activation, survival, and phagocytosis; however, the pathophysiological role of sTREM2 in AD is not well understood. Understanding the role of sTREM2 in AD may reveal new pathological mechanisms and lead to the identification of therapeutic targets. We performed a genome-wide association study (GWAS) to identify genetic modifiers of CSF sTREM2 obtained from the Alzheimer's Disease Neuroimaging Initiative. Common variants in the membrane-spanning 4-domains subfamily A (MS4A) gene region were associated with CSF sTREM2 concentrations (rs1582763; P = 1.15 × 10-15); this was replicated in independent datasets. The variants associated with increased CSF sTREM2 concentrations were associated with reduced AD risk and delayed age at onset of disease. The single-nucleotide polymorphism rs1582763 modified expression of the MS4A4A and MS4A6A genes in multiple tissues, suggesting that one or both of these genes are important for modulating sTREM2 production. Using human macrophages as a proxy for microglia, we found that MS4A4A and TREM2 colocalized on lipid rafts at the plasma membrane, that sTREM2 increased with MS4A4A overexpression, and that silencing of MS4A4A reduced sTREM2 production. These genetic, molecular, and cellular findings suggest that MS4A4A modulates sTREM2. These findings also provide a mechanistic explanation for the original GWAS signal in the MS4A locus for AD risk and indicate that TREM2 may be involved in AD pathogenesis not only in TREM2 risk-variant carriers but also in those with sporadic disease.

Primary fatty amides in plasma associated with brain amyloid burden, hippocampal volume, and memory in the European Medical Information Framework for Alzheimer's Disease biomarker discovery cohort.

INTRODUCTION: A critical and as-yet unmet need in Alzheimer's disease (AD) is the discovery of peripheral small molecule biomarkers. Given that brain pathology precedes clinical symptom onset, we set out to test whether metabolites in blood associated with pathology as indexed by cerebrospinal fluid (CSF) AD biomarkers. METHODS: This study analyzed 593 plasma samples selected from the European Medical Information Framework for Alzheimer's Disease Multimodal Biomarker Discovery study, of individuals who were cognitively healthy (n = 242), had mild cognitive impairment (n = 236), or had AD-type dementia (n = 115). Logistic regressions were carried out between plasma metabolites (n = 883) and CSF markers, magnetic resonance imaging, cognition, and clinical diagnosis. RESULTS: Eight metabolites were associated with amyloid ß and one with t-tau in CSF, these were primary fatty acid amides (PFAMs), lipokines, and amino acids. From these, PFAMs, glutamate, and aspartate also associated with hippocampal volume and memory. DISCUSSION: PFAMs have been found increased and associated with amyloid ß burden in CSF and clinical measures.

Altered Blood Gene Expression of Tumor-Related Genes (PRKCB, BECN1, and CDKN2A) in Alzheimer's Disease.

Alzheimer's disease (AD) is the most common of the neurodegenerative diseases. Recent diagnostic criteria have defined a preclinical disease phase during which neuropathological substrates are thought to be present in the brain. There is an urgent need to find measurable alterations in this phase as well as a good peripheral biomarker in the blood. We selected a cohort of 100 subjects (controls = 47; preclinical AD = 11; patients with AD = 42) and analyzed whole blood expression of 20 genes by quantitative polymerase chain reaction. The selected genes belonged to calcium signaling, senescence and autophagy, and mitochondria/oxidative stress pathways. Additionally, two genes associated with an increased risk of developing AD (clusterin (CLU) and bridging integrator 1 (BIN1)) were also analyzed. We detected significantly different gene expressions of BECN1 and PRKCB between the control and the AD groups and of CDKN2A between the control and the preclinical AD groups. Notably, these three genes are also considered tumor suppressor (CDKN2A and BECN1) or tumor promoter (PRKCB) genes. Gene-gene expression Pearson correlations were computed separately for controls and patients with AD. The significant correlations (p < 0.001) were represented in a network analysis with Cytoscape tool, which suggested an uncoupling of mitochondria-related genes in AD group. Whole blood is emerging as a valuable tissue in the study of the physiopathology of AD.

Increased glutamate/glutamine compounds in the brains of patients with fibromyalgia: a magnetic resonance spectroscopy study.

OBJECTIVE: Fibromyalgia (FM) has been defined as a systemic disorder that is clinically characterized by pain, cognitive deficit, and the presence of associated psychopathology, all of which are suggestive of a primary brain dysfunction. This study was undertaken to identify the nature of this cerebral dysfunction by assessing the brain metabolite patterns in patients with FM through magnetic resonance spectroscopy (MRS) techniques. METHODS: A cohort of 28 female patients with FM and a control group of 24 healthy women of the same age were studied. MRS techniques were used to study brain metabolites in the amygdala, thalami, and prefrontal cortex of these women. RESULTS: In comparison with healthy controls, patients with FM showed higher levels of glutamate/glutamine (Glx) compounds (mean +/- SD 11.9 +/- 1.6 arbitrary units [AU] versus 13.4 +/- 1.7 AU in controls and patients, respectively; t = 2.517, 35 df, corrected P = 0.03) and a higher Glx:creatine ratio (mean +/- SD 2.1 +/- 0.4 versus 2.4 +/- 1.4, respectively; t = 2.373, 35 df, corrected P = 0.04) in the right amygdala. In FM patients with increased levels of pain intensity, greater fatigue, and more symptoms of depression, inositol levels in the right amygdala and right thalamus were significantly higher. CONCLUSION: The distinctive metabolic features found in the right amygdala of patients with FM suggest the possible existence of a neural dysfunction in emotional processing. The results appear to extend previous findings regarding the dysfunction in pain processing observed in patients with FM.

Isolated frontal disequilibrium as presenting form of anti-Hu paraneoplastic encephalomyelitis.

Anti-Hu encephalomyelitis is one of the most frequent paraneoplastic syndromes, classically presenting with diffuse neurological involvement. We report a 69-year-old man presenting with a three-month isolated, progressive gait disorder with normal neurological examination, except for loss of balance and gait failure reminding frontal disequilibrium, only accompanied by a very mild rigidity of his right foot. MRI of the brain showed hyperintensities in both amygdale and left putamen. EMG study showed no abnormal continuous spontaneous fiber activity. Because of fast progression and MRI findings, anti-Hu antibodies were tested, resulting positive. Mediastinal biopsy of two adenopathies detected by body-PET, confirmed an oat-cell carcinoma. The patient received oral steroids and oncological therapy. One year later, the tumor is in remission. His gait and abnormal posture of right leg are normal. Only mild residual hyperintensities persist on follow-up MRI. A paraneoplastic syndrome should be considered in the differential diagnosis of subacute, fast progressive gait disorders.

Effects of pallidotomy and bilateral subthalamic stimulation on cognitive function in Parkinson disease. A controlled comparative study.

Unilateral pallidotomy and bilateral subthalamic deep brain stimulation (STN-DBS) for Parkinson's disease (PD) have demonstrated a positive effect on motor functions. However, further studies are needed of the unintended cognitive effects accompanying these new surgical procedures. We studied the consequences of unilateral pallidotomy and STN-DBS on cognitive function in a controlled comparative design. Sixteen consecutive PD patients were assessed before and 6 months after unilateral pallidotomy (n = 8) and bilateral STN-DBS (n = 8). The same assessments were performed in a control group of eight non-operated matched PD patients recruited from surgery candidates who refused operation. The neuropsychological battery consisted of test measuring memory, attention, arithmetic, problem solving and language, as well as visuospatial, executive and premotor functions. An analysis of variance (factors time and treatment) was applied. No statistically significant differences were found in the presurgical evaluation of clinical and demographic data for the three treatment groups. The controlled comparison between presurgical and postsurgical performance revealed no significant changes in the cognitive domains tested in the pallidotomy group. The STN-DBS group showed a selective significant worsening of semantic verbal fluency (p = 0.005). This controlled comparative study suggests that neither unilateral pallidotomy nor bilateral STN-DBS have global adverse cognitive consequences, but bilateral STN-DBS may cause a selective decrease in verbal fluency.