Juan Pablo Romero

Cannabinoid CB1 and CB2 Receptors and Fatty Acid Amide Hydrolase Are Specific Markers of Plaque Cell Subtypes in Human Multiple Sclerosis

Increasing evidence supports the idea of a beneficial effect of cannabinoid compounds for the treatment of multiple sclerosis (MS). However, most experimental data come from animal models of MS. We investigated the status of cannabinoid CB1 and CB2 receptors and fatty acid amide hydrolase (FAAH) enzyme in brain tissue samples obtained from MS patients. Areas of demyelination were identified and classified as active, chronic, and inactive plaques. CB1 and CB2 receptors and FAAH densities and cellular sites of expression were examined using immunohistochemistry and immunofluorescence. In MS samples, cannabinoid CB1 receptors were expressed by cortical neurons, oligodendrocytes, and also oligodendrocyte precursor cells, demonstrated using double immunofluorescence with antibodies against the CB1 receptor with antibodies against type 2 microtubule-associated protein, myelin basic protein, and the platelet-derived growth factor receptor-α, respectively. CB1 receptors were also present in macrophages and infiltrated T-lymphocytes. Conversely, CB2 receptors were present in T-lymphocytes, astrocytes, and perivascular and reactive microglia (major histocompatibility complex class-II positive) in MS plaques. Specifically, CB2-positive microglial cells were evenly distributed within active plaques but were located in the periphery of chronic active plaques. FAAH expression was restricted to neurons and hypertrophic astrocytes. As seen for other neuroinflammatory conditions, selective glial expression of cannabinoid CB1 and CB2 receptors and FAAH enzyme is induced in MS, thus supporting a role for the endocannabinoid system in the pathogenesis and/or evolution of this disease.

Cannabinoid CB2 receptor agonists protect the striatum against malonate toxicity: relevance for Huntington's disease.

Cannabinoid agonists might serve as neuroprotective agents in neurodegenerative disorders. Here, we examined this hypothesis in a rat model of Huntingtons disease (HD) generated by intrastriatal injection of the mitochondrial complex II inhibitor malonate. Our results showed that only compounds able to activate CB2 receptors were capable of protecting striatal projection neurons from malonate‐induced death. That CB2 receptor agonists are neuroprotective was confirmed by using the selective CB2 receptor antagonist, SR144528, and by the observation that mice deficient in CB2 receptor were more sensitive to malonate than wild‐type animals. CB2 receptors are scarce in the striatum in healthy conditions, but they are markedly upregulated after the lesion with malonate. Studies of double immunostaining revealed a significant presence of CB2 receptors in cells labeled with the marker of reactive microglia OX‐42, and also in cells labeled with GFAP (a marker of astrocytes). We further showed that the activation of CB2 receptors significantly reduced the levels of tumor necrosis factor‐α (TNF‐α) that had been increased by the lesion with malonate. In summary, our results demonstrate that stimulation of CB2 receptors protect the striatum against malonate toxicity, likely through a mechanism involving glial cells, in particular reactive microglial cells in which CB2 receptors would be upregulated in response to the lesion. Activation of these receptors would reduce the generation of proinflammatory molecules like TNF‐α. Altogether, our results support the hypothesis that CB2 receptors could constitute a therapeutic target to slowdown neurodegeneration in HD.

Circulating Tumor Cells: Clinically Relevant Molecular Access Based on a Novel CTC Flow Cell

Background Contemporary cancer diagnostics are becoming increasing reliant upon sophisticated new molecular methods for analyzing genetic information. Limiting the scope of these new technologies is the lack of adequate solid tumor tissue samples. Patients may present with tumors that are not accessible to biopsy or adequate for longitudinal monitoring. One attractive alternate source is cancer cells in the peripheral blood. These rare circulating tumor cells (CTC) require enrichment and isolation before molecular analysis can be performed. Current CTC platforms lack either the throughput or reliability to use in a clinical setting or they provide CTC samples at purities that restrict molecular access by limiting the molecular tools available. Methodology/Principal Findings Recent advances in magetophoresis and microfluidics have been employed to produce an automated platform called LiquidBiopsy®. This platform uses high throughput sheath flow microfluidics for the positive selection of CTC populations. Furthermore the platform quantitatively isolates cells useful for molecular methods such as detection of mutations. CTC recovery was characterized and validated with an accuracy (<20% error) and a precision (CV<25%) down to at least 9 CTC/ml. Using anti-EpCAM antibodies as the capture agent, the platform recovers 78% of MCF7 cells within the linear range. Non specific recovery of background cells is independent of target cell density and averages 55 cells/mL. 10% purity can be achieved with as low as 6 CTCs/mL and better than 1% purity can be achieved with 1 CTC/mL. Conclusions/Significance The LiquidBiopsy platform is an automated validated platform that provides high throughput molecular access to the CTC population. It can be validated and integrated into the lab flow enabling CTC enumeration as well as recovery of consistently high purity samples for molecular analysis such as quantitative PCR and Next Generation Sequencing. This tool opens the way for clinically relevant genetic profiling of CTCs.

Long sleep duration in elders without dementia increases risk of dementia mortality (NEDICES).

Objective: To determine in a population-based study whether long sleep duration was associated with increased risk of dementia mortality. Methods: In this prospective, population-based study of 3,857 people without dementia aged 65 years and older (NEDICES [Neurological Disorders in Central Spain]), participants reported their daily sleep duration. The average daily total sleep duration was grouped into 3 categories: ≤5 hours (short sleepers), 6–8 hours (reference category), and ≥9 hours (long sleepers). Community-dwelling elders were followed for a median of 12.5 years, after which the death certificates of those who died were examined. Results: A total of 1,822 (47.2%) of 3,857 participants died, including 201 (11.0%) deaths among short sleepers, 832 (45.7%) among long sleepers, and 789 (43.3%) among those participants in the reference category. Of 1,822 deceased participants, 92 (5.1%) had a dementia condition reported on the death certificate (49 [53.3%] were long sleepers, 36 [39.1%] reported sleeping between 6 and 8 hours, and 7 [7.6%] were short sleepers). In an unadjusted Cox model, risk of dementia-specific mortality was increased in long sleepers (hazard ratio for dementia mortality in long sleepers = 1.58, p = 0.04) when compared with the reference group. In a Cox model that adjusted for numerous demographic factors and comorbidities, the hazard ratio for dementia mortality in long sleepers was 1.63 (p = 0.03). Conclusions: Self-reported long sleep duration was associated with 58% increased risk of dementia-specific mortality in this cohort of elders without dementia. Future studies are required to confirm these findings.

Online Tremor Suppression Using Electromyography and Low-Level Electrical Stimulation

Tremor is one of the most prevalent movement disorders. There is a large proportion of patients (around 25%) in whom current treatments do not attain a significant tremor reduction. This paper proposes a tremor suppression strategy that detects tremor from the electromyographic signals of the muscles from which tremor originates and counteracts it by delivering electrical stimulation to the antagonist muscles in an out of phase manner. The detection was based on the iterative Hilbert transform and stimulation was delivered above the motor threshold (motor stimulation) and below the motor threshold (sensory stimulation). The system was tested on six patients with predominant wrist flexion/extension tremor (four with Parkinson disease and two with Essential tremor) and led to an average tremor reduction in the range of 46%-81% and 35%-48% across five patients when using the motor and sensory stimulation, respectively. In one patient, the system did not attenuate tremor. These results demonstrate that tremor attenuation might be achieved by delivering electrical stimulation below the motor threshold, preventing muscle fatigue and discomfort for the patients, which sets the basis for the development of an alternative treatment for tremor.

Altered Functional Connectivity in Essential Tremor: A Resting-State fMRI Study.

AbstractEssential tremor (ET) has been associated with a spectrum of clinical features, with both motor and nonmotor elements, including cognitive deficits. We employed resting-state functional magnetic resonance imaging (fMRI) to assess whether brain networks that might be involved in the pathogenesis of nonmotor manifestations associated with ET are altered, and the relationship between abnormal connectivity and ET severity and neuropsychological function.Resting-state fMRI data in 23 ET patients (12 women and 11 men) and 22 healthy controls (HC) (12 women and 10 men) were analyzed using independent component analysis, in combination with a “dual-regression” technique, to identify the group differences of resting-state networks (RSNs) (default mode network [DMN] and executive, frontoparietal, sensorimotor, cerebellar, auditory/language, and visual networks). All participants underwent a neuropsychological and neuroimaging session, where resting-state data were collected.Relative to HC, ET patients showed increased connectivity in RSNs involved in cognitive processes (DMN and frontoparietal networks) and decreased connectivity in the cerebellum and visual networks. Changes in network integrity were associated not only with ET severity (DMN) and ET duration (DMN and left frontoparietal network), but also with cognitive ability. Moreover, in at least 3 networks (DMN and frontoparietal networks), increased connectivity was associated with worse performance on different cognitive domains (attention, executive function, visuospatial ability, verbal memory, visual memory, and language) and depressive symptoms. Further, in the visual network, decreased connectivity was associated with worse performance on visuospatial ability.ET was associated with abnormal brain connectivity in major RSNs that might be involved in both motor and nonmotor symptoms. Our findings underscore the importance of examining RSNs in this population as a biomarker of disease.

Alzheimer's Disease is Associated with Decreased Risk of Cancer-Specific Mortality: A Prospective Study (NEDICES)

Previous studies have shown that Alzheimers disease (AD) is associated with a reduced risk of cancer. However, most studies exclude those with undiagnosed dementia. The only way to overcome this methodological issue is to examine all the participants or to screen the population for symptoms of dementia with a validated instrument and confirm any suspected dementia patients with a clinical examination (i.e., a two-phase investigation method). We used this methodology to estimate whether cancer-specific mortality is associated with AD and other types of dementia in a prospective population-based study (NEDICES) involving 5,278 elderly people. Community-dwelling subjects with and without dementia were identified and followed for a median of 12.5 years, after which the death certificates of those who deceased were examined. A total of 1,976 (47.1%) died, including 277 who had possible or probable AD and 126 with non-AD dementia. Cancer was reported significantly less often in those with possible or probable AD (5.8%) or non-AD dementia (6.3%) than in those without dementia (26.5%). In an unadjusted Cox model, hazard ratio (HR) of cancer-specific mortality in participants with AD = 0.45 (p = 0.002) and HR in participants with non-AD dementia = 0.62 (p = 0.179) when compared to the non-demented group. In a Cox model that adjusted for a variety of demographic factors and co-morbidities, HRs of cancer-specific mortality in participants with AD = 0.50 (p = 0.028) and 0.97 (p = 0.942) in non-AD dementia. This study provides further evidence of an inverse association between cancer and AD.

Under Reporting of Dementia Deaths on Death Certificates: A Systematic Review of Population-based Cohort Studies

The purpose of this review is to assess the extent to which dementia is omitted as a cause of death from the death certificates of patients with dementia. A systematic literature search was performed to identify population-based cohort studies in which all participants were examined or screened for symptoms of dementia with a validated instrument followed by confirmation of any suspected cases with a clinical examination (two-phase investigation). Data were extracted in a standardized manner and assessed through the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) initiative. Seven studies met the selection criteria. These were from the Americas (5 articles: 2 from Canada, 2 from the US, and 1 from Brazil) and Europe (2 articles: 1 from the UK and 1 from Spain). Each met at least 83% of the STROBE criteria. The reporting of dementia on death certificates was poor in these 7 studies, ranging from 7.2%-41.8%. Respiratory or circulatory-related problems were the most frequently reported causes of death among people who were demented but who were not reported as demented on death certificates. The use of death certificates for studying dementia grossly underestimates the occurrence of dementia in the population. The poor reporting of dementia on these certificates suggests a lack of awareness of the importance of dementia as a cause of death among medical personnel. There is an urgent need to provide better education on the importance of codification of dementia on death certificates in order to minimize errors in epidemiological studies on dementia.

Faster cognitive decline in elders without dementia and decreased risk of cancer mortality NEDICES Study

Objective: To assess whether faster cognitive decline in elders without dementia is associated with decreased risk of cancer mortality. Methods: In this population-based, prospective study of 2,627 people without dementia aged 65 years and older (Neurological Disorders in Central Spain), a 37-item version of the Mini-Mental State Examination (37-MMSE) was administered at 2 visits (baseline and follow-up, approximately 3 years later). We divided change in 37-MMSE into tertiles (lower tertile ≥2 point improvement in score, higher tertile ≥2 point decline in score). Community-dwelling elders were followed for a median of 12.9 years, after which the death certificates of those who died were examined. Results: A total of 1,003 (38.2%) died, including 339 (33.8%) deaths among participants who were in the higher tertile of 37-MMSE change and 664 (66.2%) deaths among those in the remaining tertiles. Cancer was reported significantly less often in those in the higher tertile of MMSE change (20.6%) than in those in the remaining tertiles (28.6%): in an unadjusted Cox model, hazard ratio for cancer mortality in participants within the higher tertile = 0.75 (p = 0.04) compared with the participants within the remaining tertiles. In a Cox model that adjusted for a variety of demographic factors and comorbidities, hazard ratio for cancer mortality in participants within the higher tertile = 0.70 (p = 0.01). Conclusion: In this population-based, prospective study of community-dwelling elders without dementia, faster cognitive decline was associated with a decreased risk of cancer mortality. Further studies are required to elucidate this inverse association in elders without dementia.

Cognitive and neuropsychiatric features of orthostatic tremor: A case–control comparison

INTRODUCTION Evidence suggests that the cerebellum could play a role in the pathophysiology of orthostatic tremor. The link between orthostatic tremor and the cerebellum is of interest, especially in light of the role the cerebellum plays in cognition, and it raises the possibility that orthostatic tremor patients could have cognitive deficits consistent with cerebellar dysfunction. Our aim was to examine whether orthostatic tremor patients had cognitive deficits and distinct personality profiles when compared with matched controls. METHODS Sixteen consecutive orthostatic tremor patients (65.7 ± 13.3 years) and 32 healthy matched controls underwent a neuropsychological battery and the Personality Assessment Inventory. In linear regression models, the dependent variable was each one of the neuropsychological test scores or the Personality Assessment Inventory subscales and the independent variable was orthostatic tremor vs. RESULTS Adjusted for age in years, sex, years of education, comorbidity index, current smoker, and depressive symptoms, diagnosis (orthostatic tremor vs. healthy control) was associated with poor performance on tests of executive function, visuospatial ability, verbal memory, visual memory, and language tests, and on a number of the Personality Assessment Inventory subscales (somatic concerns, anxiety related disorders, depression, and antisocial features). Older-onset OT (>60 years) patients had poorer scores on cognitive and personality testing compared with their younger-onset OT counterparts. CONCLUSION Orthostatic tremor patients have deficits in specific aspects of neuropsychological functioning, particularly those thought to rely on the integrity of the prefrontal cortex, which suggests involvement of frontocerebellar circuits. Cognitive impairment and personality disturbances could be disease-associated nonmotor manifestations of orthostatic tremor.