Search

In the course of neurodegenerative disorders there are several mechanisms that may counteract the pathological process, mitigating the clinical manifestations of the disease. Usually referred as cognitive reserve hypothesis, this theoretical framework posits that individuals with enriched cognitive status (i.e. with higher educational and occupational levels and higher individual social achievement) may cope better with the occurrence of cognitive decline by a more efficient recruitment of neural networks sustaining higher-level functions. Cognitive reserve was initially studied in Alzheimers disease, but this concept has been soon after extended also to other neurodegenerative disorders, such as Frontotemporal Dementia, Parkinsons disease, and Huntingtons disease, suggesting a general applicability of cortical plasticity phenomena in contrasting neurodegeneration. The neural underpinnings of these dynamic compensatory mechanisms open the possibility for strategic interventions based on environmental approaches. In this continuously growing field, the aim of the present review is to explore new acquisitions, derived from basic research and clinical grounds, on cognitive reserve mechanisms and the potential application as novel therapeutic targets in neurodegenerative diseases.

Frontotemporal Lobar Degeneration (FTLD) is characterized by behavioral changes, executive dysfunctions, and language impairment, sustained by different neuropathological patterns. The collective efforts of clinical, pathological and genetic studies have recently opened new insights into the underpinnings of pathological mechanisms of this complex disorder. Different types of inclusions define the new conceptual framework for FTLD classification. Up to now, Tau (FTLDTau-positive), TAR DNA-binding protein (TDP43, FTLD Tau-negative TDP43-positive) have been recognized as the most frequent neuropathological hallmarks of FTLD. In some clinical cases, monogenic forms are identified, mainly due to Microtubule Associated Protein (MAPT) or Granulin (GRN) mutations. No treatments for FTLD are available yet, and off-label medications studies testing potential modifying treatments on the basis of neuropathological positive, inhibitors of Tau kinases or manipulation of Tau-processing haploinsuffciency associated with GRN mutations, has been counteracted into pathological processing of TDP-43 and other key-molecules involved and their consequent translocation from nucleus to cytoplasm, and growing number of potential therapeutic targets. In this continuously new findings on molecular targets and modifying therapies in FTLD.

Frontotemporal Lobar Degeneration (FTLD) is a genetically and pathologically heterogeneous disorder characterized by behavioral change, executive dysfunction and language impairment associated with frontal and temporal lobe degeneration. Three major clinical subtypes have been identified so far, namely behaviour variant Frontotemporal dementia (bvFTD), Semantic Dementia (SD) and Progressive Non-Fluent Aphasia (PNFA). FTLD might also overlap with atypical parkinsonisms or motor neuron disease. Several pathogenetic mutations have been associated with specific pathological and clinical correlates. FTLD associated with either Microtuble Associated Protein Tau (MAPT) or Progranulin (PGRN) mutations is recognised as the most common form of autosomal dominant inherited disorder. However, monogenic mutations account for only about one third of all FTLD cases. Several studies have evaluated the contribution of genetic background in non-monogenic forms of FTLD, with the attempt to establish its role in increasing disease risk and in modulating clinical phenotypes. Specific MAPT and PGRN polymorphisms have been demonstrated to affect disease onset, clinical features and prognosis of FTLD, and genetic variations within other genes appear to play a role in influencing disease risk and clinical expression of FTLD. The aim of the present review is to discuss the impact and the role of genetic background in non-monogenic forms of FTLD, to highlight new potential pathogenetic and therapeutic targets.

It is becoming increasingly clearer that the clinical manifestations of Alzheimers disease (AD) are not only associated with regional grey matter (GM) damage, but also with abnormal integration between cortical brain regions by disconnection mechanism. This concept comes from the evidence that white matter (WM) damage (as assessed by diffusion MR imaging) can be observed in patients with AD since the early clinical stages, and it correlates with clinical measures of cognitive disability. In this perspective, several functional imaging studies, based on PET and resting state fMRI, have provided evidence that brain hypometabolism/disconnection may precede the occurrence of GM atrophy in certain regions of AD brains, such as the cingulate cortex. The cingulum represents the most prominent WM tract of the limbic system, being directly connected to the medial temporal lobe structures. Therefore, this structure likely contributes to changes in functional connectivity observed within the so called default-mode network of AD patients, and its damage is likely to play a remarkable role in the conversion from mild cognitive impairment (MCI) to dementia. Nowadays, the combination of several neuroimaging techniques that provide both, measures of regional GM loss and measures of functional and structural connectivity offer the opportunity to investigate in vivo the pathophysiological changes of brain tissue modifications across the clinical evolution of AD. This paper reviews the main MR based methods of investigation of brain tissue involvement in patients with AD and MCI, and the role they have played in clarifying the differential contribution of GM damage and brain disconnection to AD pathophysiology. This subject seems to be relevant for both, speculative aspects of neurology and application to clinical trials.

Frontotemporal Lobar degeneration (FTLD) is one of the most important neurodegenerative conditions, affecting in the presenium, but more recently recognized also in aged population. The strong genetic background, along with autopsy determinations prompted the identification of the two major genes associated to the disease: MAPT gene, and Progranulin (PGRN) gene. In this review, we highlighted the milestones of these discoveries, and their implication for the development of future therapeuthical approaches.

Alzheimers disease (AD) is a neurodegenerative disorder characterized by progressive cognitive decline including loss of memory, orientation and reasoning. However, a relevant aspect of AD is the presence of a variety of behavioural and psychological symptoms in dementia (BPSD), beyond the well-known progressive cognitive impairment. Approximately 50 to 80 of patients diagnosed with AD present behavioural or psychiatric disturbances such as psychosis, depression, agitation, disinhibition, aggression, hyperactivity, and socially intrusive behaviours. These symptoms may be burdensome for physicians and caregivers and lead to earlier institutionalization and increased social and economic costs. In this view, recent literature has considered the likely genetic component of BPSD in AD, defining different clusters. Several studies have investigated whether the main recognised genetic risk factor for late-onset AD, namely the apolipoprotein E (APOE) gene, is associated with BPSD, with conflicting results. The involvement of dopamine- or serotonin- related pathways and associated genetic variabilities has been demonstrated as being interesting candidates for the neuropsychiatry manifestations of dementia. Moreover, genetic variations of neurotrophins, such as brain-derived neurotrophic factor (BDNF), have been related to depression susceptibility in AD. In the present review, we summarise the current literature on genetic risk factors to BPSD susceptibility in AD and discuss future possible treatment strategies.

In CSF, extended (55 kDa) and truncated (33 kDa) tau forms have been previously recognized, and the tau 33 kDa/55 kDa ratio has been found significantly reduced in progressive supranuclear palsy (PSP) vs in other neurodegenerative disorders. The aim of this study was to evaluate the diagnostic value of the CSF tau form ratio as a biomarker of PSP and to correlate the structural anatomic changes as measured by means of voxel-based morphometry (VBM) to CSF tau form ratio decrease.

Previous reports have shown that higher education is associated with more severe brain pathology in patients with Alzheimer disease (AD), suggesting that these individuals have a functional reserve provided by education, which masks the clinical expression of a higher degree of neurodegeneration. It is unknown if a similar reserve mechanism exists in patients with amnestic mild cognitive impairment (aMCI). The aim of this study was to assess the impact of education and occupation on brain glucose metabolism (rCMRglc) measured with FDG-PET in aMCI and in a very large sample of subjects with probable AD (pAD).

To investigate whether the combination of fluoro-2-deoxy-d-glucose (FDG) PET measures with the APOEgenotype would improve prediction of the conversion from mild cognitive impairment (MCI) to Alzheimer disease (AD).

Amyloid precursor protein (APP), ADAM 10, and -site-APP cleaving enzyme (BACE) alterations were evaluated in platelets of 31 patients with Alzheimer disease (AD) and 15 age-matched controls. A significant modification of these proteins and enzymes involved in the amyloid cascade was detected from the earliest clinically detectable disease stage. This observation suggests that AD is associated with an early metabolic derangement toward amyloidogenic pathways and supports the potential value of APP and secretase measurements for early diagnosis of AD.

An altered pattern of amyloid precursor protein (APP) forms consisting in a reduced ratio between the upper (130 kDa) and the lower (106 to 110 kDa) immunoreactivity bands has been described in platelets of patients with AD.

Este estudio comparó el rendimiento de las adquisiciones tempranas de 18F-florbetapir PET/TC con el de 18F-FDG PET/TC.