Longstanding Endobronchial Foreign Body

There are many circumstances in which the diagnosis of endobronchial inhalation of a foreign body (FB) can be missed. Generally, in such cases, within weeks or at most months from the event, clinical bronchopulmonary symptoms develop which allow a correct diagnosis to be made and significant complications to be avoided. We report the case of a patient in whom an endobronchial FB remained undiagnosed, because of lack of symptoms, for almost three years, and then caused signifiicant complications before being identified and removed. Problems related to diagnosis and therapy are discussed

Tackling amyloidogenesis in Alzheimer's disease with A2V variants of Amyloid-β

We developed a novel therapeutic strategy for Alzheimer’s disease (AD) exploiting the properties of a natural variant of Amyloid-β (Aβ) carrying the A2V substitution, which protects heterozygous carriers from AD by its ability to interact with wild-type Aβ, hindering conformational changes and assembly thereof. As prototypic compound we designed a six-mer mutated peptide (Aβ1-6A2V), linked to the HIV-related TAT protein, which is widely used for brain delivery and cell membrane penetration of drugs. The resulting molecule [Aβ1-6A2VTAT(D)] revealed strong anti-amyloidogenic effects in vitro and protected human neuroblastoma cells from Aβ toxicity. Preclinical studies in AD mouse models showed that short-term treatment with Aβ1-6A2VTAT(D) inhibits Aβ aggregation and cerebral amyloid deposition, but a long treatment schedule unexpectedly increases amyloid burden, although preventing cognitive deterioration. Our data support the view that the AβA2V-based strategy can be successfully used for the development of treatments for AD, as suggested by the natural protection against the disease in human A2V heterozygous carriers. The undesirable outcome of the prolonged treatment with Aβ1-6A2VTAT(D) was likely due to the TAT intrinsic attitude to increase Aβ production, avidly bind amyloid and boost its seeding activity, warning against the use of the TAT carrier in the design of AD therapeutics

PMCA-Based Detection of Prions in the Olfactory Mucosa of Patients With Sporadic Creutzfeldt–Jakob Disease

Sporadic Creutzfeldt-Jakob disease (sCJD) is a rare neurodegenerative disorder caused by the conformational conversion of the prion protein (PrPC) into an abnormally folded form, named prion (or PrPSc). The combination of the polymorphism at codon 129 of the PrP gene (coding either methionine or valine) with the biochemical feature of the proteinase-K resistant PrP (generating either PrPSc type 1 or 2) gives rise to different PrPSc strains, which cause variable phenotypes of sCJD. The definitive diagnosis of sCJD and its classification can be achieved only post-mortem after PrPSc identification and characterization in the brain. By exploiting the Real-Time Quaking-Induced Conversion (RT-QuIC) assay, traces of PrPSc were found in the olfactory mucosa (OM) of sCJD patients, thus demonstrating that PrPSc is not confined to the brain. Here, we have optimized another technique, named protein misfolding cyclic amplification (PMCA) for detecting PrPSc in OM samples of sCJD patients. OM samples were collected from 27 sCJD and 2 genetic CJD patients (E200K). Samples from 34 patients with other neurodegenerative disorders were included as controls. Brains were collected from 26 sCJD patients and 16 of them underwent OM collection. Brain and OM samples were subjected to PMCA using the brains of transgenic mice expressing human PrPC with methionine at codon 129 as reaction substrates. The amplified products were analyzed by Western blot after proteinase K digestion. Quantitative PMCA was performed to estimate PrPSc concentration in OM. PMCA enabled the detection of prions in OM samples with 79.3% sensitivity and 100% specificity. Except for a few cases, a predominant type 1 PrPSc was generated, regardless of the tissues analyzed. Notably, all amplified PrPSc were less resistant to PK compared to the original strain. In conclusion, although the optimized PMCA did not consent to recognize sCJD subtypes from the analysis of OM collected from living patients, it enabled us to estimate for the first time the amount of prions accumulating in this biological tissue. Further assay optimizations are needed to faithfully amplify peripheral prions whose recognition could lead to a better diagnosis and selection of patients for future clinical trials

The role of rho-gtpases in the aetiology of Alzheimer's disease

AIMS: The progression of Alzheimer’s disease (AD) is characterized by a wide synaptic and dendritic loss whose mechanisms are still unknown. We aimed at studying the potential role of Rho-GTPases, key regulator of spine dynamics, as biomarkers for AD and interacting partners of tau and beta-amyloid peptide (Abeta). METHOD: Rac1 and Cdc42 levels were measured by ELISA in the plasma of AD patients (n=101), age and sex-matched healthy controls (n=102) as well as in frontal cortex of autoptic brain samples. The 3xTgAD mouse model was used to correlate the alteration of Rho-GTPases in the brain to the progression of the disease. To investigate the molecular mechanisms connecting Rho-GTPases to Abeta and tau, mouse primary cortical neurons were treated with Rho-GTPase mutant proteins, Rac1 and Cdc42, and immunocytochemistry and pull down assays were performed. RESULTS: Rac1 was significantly increased in plasma of AD patients and significantly decreased in AD brain homogenates compared to controls. The underlined involvement of Rac1 was confirmed by the decreased levels of Rac1 in the cortex of 7 month old 3xTgAD. Rac1 deregulation affected Aß metabolism and tau regulators. CONCLUSION: Our data proposes a putative pathway in which Rac1 is able to affect the regulation of AD relevant proteins. Moreover, we show that Rac1 is increased in AD plasma suggesting its novel role as a biomarker for AD and as a promising therapeutic target

Good gene, bad gene : new APP variant may be both

APP mutations cause Alzheimer disease (AD) with virtually complete penetrance. We found a novel APP mutation (A673V) in the homozygous state in a patient with early-onset AD-type dementia and in his younger sister showing initial signs of cognitive decline. It is noteworthy that the heterozygous relatives were not affected, suggesting that this mutation is inherited as an autosomal recessive trait. Studies on molecular events for the recessive mutation in causing disease revealed a double synergistic effect: the A673V APP variant shifts APP processing towards the amyloidogenic pathway with increased production of A\u3b2 peptides and it markedly enhances the aggregation and fibrillogenic properties of both A\u3b21-40 and A\u3b21-42. However, co-incubation of mutated and wild-type (wt) A\u3b2 species resulted in inhibition of amyloidogenesis, consistent with the observation that heterozygous carriers do not develop the disease. The opposite effects of the A673V mutation in the homozygous and heterozygous state on amyloidogenesis account for the autosomal recessive pattern of inheritance, revealing a new scenario in AD genetics and pathogenesis. The anti-amyloidogenic properties of this novel human A\u3b2 variant may offer grounds for the development of therapeutic strategies for AD based on modified A\u3b2 peptides. Indeed, the interaction between mutated A\u3b21-6 and wt full-length A\u3b2 prevents amyloid fibril formation. The anti-amyloidogenic effect is further amplified by the use of a mutated six-mer peptide, constructed entirely from D-amino acids to increase the its stability in vivo. Here we reviewed the studies on pathogenic mechanisms associated with the A673V mutation and the first experimental steps toward the development of a novel disease-modifying therapy for AD. \ua9 2012 Elsevier Ltd