Spontaneous intracerebral haemorrhage associated with early-onset cerebral amyloid angiopathy and Alzheimer's disease neuropathological changes five decades after cadaveric dura mater graft.

Cerebral amyloid angiopathy (CAA) is a small vessel disease, causing spontaneous intracerebral hemorrhage (ICH) in the elderly. It is strongly associated with Alzheimer disease (AD), as most CAA patients show deposition of Aß-i.e. the basic component of parenchymal Alzheimer amyloid deposits-in the cerebral vessels. Iatrogenic early-onset CAA has been recently identified in patients with a history of traumatic brain injury or other cerebral as well as extra-cerebral lesions that led to neurosurgery or other medical procedures as intravascular embolization by cadaveric dura mater extracts many years before the first ICH event. In those patients, a transmission of Aß seeds from neurosurgical instruments or from cadaveric dura mater exposure was suggested. We report a 51-year-old woman with unremarkable family history who presented abruptly with aphasia and right hemiparesis. A cerebral left lobar haemorrhagic stroke was documented by neuroimaging. Accurate anamnesis revealed a neurosurgical procedure with cadaveric dura mater graft at the age of 2 years for an arachnoid cyst. The neuropathological examination of the cerebral parietal biopsy showed severe amyloid angiopathy in many leptomeningeal and cortical vessels, as well as abundant parenchymal Aß deposits, neurofibrillary tangles and neuropil threads. The mechanism involved in the human-to-human transmission of the Aß proteinopathy remains to be clarified. In our patient the cadaver derived dura used for grafting is a very strong candidate as the source of the transmission. A systematic monitoring of individuals who have had neurosurgical procedures in early life, especially those involving cadaveric dural grafts, is required to determine the ratio of those affected by CAA many years later and unaffected. Moreover, our report confirms that in addition to vascular and parenchymal Aß pathology, neurofibrillary changes indistinguishable from AD may develop in specific conditions with long latency period from the neurosurgical or embolization procedure.

Cerebrospinal Fluid EV Concentration and Size Are Altered in Alzheimer's Disease and Dementia with Lewy Bodies.

Alzheimer's disease (AD), dementia with Lewy bodies (DLB) and frontotemporal dementia (FTD) represent the three major neurodegenerative dementias characterized by abnormal brain protein accumulation. In this study, we investigated extracellular vesicles (EVs) and neurotrophic factors in the cerebrospinal fluid (CSF) of 120 subjects: 36 with AD, 30 with DLB, 34 with FTD and 20 controls. Specifically, CSF EVs were analyzed by Nanoparticle Tracking Analysis and neurotrophic factors were measured with ELISA. We found higher EV concentration and lower EV size in AD and DLB groups compared to the controls. Classification tree analysis demonstrated EV size as the best parameter able to discriminate the patients from the controls (96.7% vs. 3.3%, respectively). The diagnostic performance of the EV concentration/size ratio resulted in a fair discrimination level with an area under the curve of 0.74. Moreover, the EV concentration/size ratio was associated with the p-Tau181/Aß42 ratio in AD patients. In addition, we described altered levels of cystatin C and progranulin in the DLB and AD groups. We did not find any correlation between neurotrophic factors and EV parameters. In conclusion, the results of this study suggest a common involvement of the endosomal pathway in neurodegenerative dementias, giving important insight into the molecular mechanisms underlying these pathologies.

Plasma Extracellular Vesicle Size and Concentration Are Altered in Alzheimer's Disease, Dementia With Lewy Bodies, and Frontotemporal Dementia.

Alzheimer's disease (AD), frontotemporal dementia (FTD), and dementia with Lewy bodies (DLB) are the three major neurodegenerative dementias. In this study, we provide evidence that an alteration in extracellular vesicles (EVs) release is common across the three most common neurodegenerative dementias, AD, DLB, and FTD. Specifically, we analyzed plasma EVs in three groups of patients affected by AD, DLB, and FTD, and we found a significant reduction in EVs concentration and larger EVs size in all patient groups. We then investigated whether the loss of neurotrophic factors is also a common pathogenic mechanism among FTD, DLB, and AD, and if levels of neurotrophic factors might affect EVs release. Plasma levels of progranulin and cystatin C (CysC) were partially altered; however, taking together all variables significantly associated with the diagnostic groups only EVs size and concentration were able to distinguish patients from controls. The diagnostic performance of these two EVs parameters together (ratio) was high, with a sensitivity of 83.3% and a specificity of 86.7%, able to distinguish patients from controls but not to differentiate the different forms of dementias. Among the candidate neurotrophic factors, only CysC levels were associated with EVs concentration. Our study suggests that an alteration in the intercellular communication mediated by EVs might be a common molecular pathway underlying neurodegenerative dementias. The identification of shared disease mechanisms is of pivotal importance to develop treatments to delay disease progression. To this aim, further studies investigating plasma EVs size and concentration as early biomarkers of dementia are required.

Machine Learning Profiling of Alzheimer's Disease Patients Based on Current Cerebrospinal Fluid Markers and Iron Content in Biofluids.

Alzheimer's disease (AD) is the most common form of dementia, characterized by a complex etiology that makes therapeutic strategies still not effective. A true understanding of key pathological mechanisms and new biomarkers are needed, to identify alternative disease-modifying therapies counteracting the disease progression. Iron is an essential element for brain metabolism and its imbalance is implicated in neurodegeneration, due to its potential neurotoxic effect. However, the role of iron in different stages of dementia is not clearly established. This study aimed to investigate the potential impact of iron both in cerebrospinal fluid (CSF) and in serum to improve early diagnosis and the related therapeutic possibility. In addition to standard clinical method to detect iron in serum, a precise quantification of total iron in CSF was performed using graphite-furnace atomic absorption spectrometry in patients affected by AD, mild cognitive impairment, frontotemporal dementia, and non-demented neurological controls. The application of machine learning techniques, such as clustering analysis and multiclassification algorithms, showed a new potential stratification of patients exploiting iron-related data. The results support the involvement of iron dysregulation and its potential interaction with biomarkers (Tau protein and Amyloid-beta) in the pathophysiology and progression of dementia.

Rac1 activation links tau hyperphosphorylation and Aß dysmetabolism in Alzheimer's disease.

One of the earliest pathological features characterizing Alzheimer's disease (AD) is the loss of dendritic spines. Among the many factors potentially mediating this loss of neuronal connectivity, the contribution of Rho-GTPases is of particular interest. This family of proteins has been known for years as a key regulator of actin cytoskeleton remodeling. More recent insights have indicated how its complex signaling might be triggered also in pathological conditions. Here, we showed that the Rho-GTPase family member Rac1 levels decreased in the frontal cortex of AD patients compared to non-demented controls. Also, Rac1 increased in plasma samples of AD patients with Mini-Mental State Examination < 18 compared to age-matched non demented controls. The use of different constitutively active peptides allowed us to investigate in vitro Rac1 specific signaling. Its activation increased the processing of amyloid precursor protein and induced the translocation of SET from the nucleus to the cytoplasm, resulting in tau hyperphosphorylation at residue pT181. Notably, Rac1 was abnormally activated in the hippocampus of 6-week-old 3xTg-AD mice. However, the total protein levels decreased at 7-months. A rescue strategy based on the intranasal administration of Rac1 active peptide at 6.5 months prevented dendritic spine loss. This data suggests the intriguing possibility of a dual role of Rac1 according to the different stages of the pathology. In an initial stage, Rac1 deregulation might represent a triggering co-factor due to the direct effect on Aß and tau. However, at a later stage of the pathology, it might represent a potential therapeutic target due to the beneficial effect on spine dynamics.

How to Monitor the Neuroimmune Biological Response in Patients Affected by Immune Alteration-Related Systemic Diseases.

The clinical management of patients affected by systemic diseases, including cancer and autoimmune diseases, is generally founded on the evaluation of the only markers related to the single disease rather than the biological immuno-inflammatory response of patients, despite the fundamental role of cytokine network in the pathogenesis of cancer and autoimmunity is well known. Cancer progression has appeared to be associated with a progressive decline in the blood levels of the main antitumor cytokines, including IL-2 and IL-12, in association with an increase in those of inflammatory cytokines, including IL-6, TNF-alpha, and IL-1-beta, and immunosuppressive cytokines, namely TGF-beta and IL-10. On the other hand, the severity of the autoimmune diseases has been proven to be greater in the presence of high blood levels of IL-17, TNF-alpha, IL-6, IL-1-beta, IFN-gamma, and IL-18, in association with low levels of TGF-beta and IL-10. However, because of excessive cost and complexity of analyzing the data regarding the secretion of the single cytokines, the relation between lymphocyte-induced immune activation and monocyte-macrophage-mediated immunosuppression has been recently proven to be expressed by the simple lymphocyte-to-monocyte ratio (LMR). The evidence of low LMR values has appeared to correlate with a poor prognosis in cancer and with a disease control in the autoimmune diseases. Moreover, since the in vivo immunoinflammatory response is physiologically under a neuroendocrine modulation, for the evaluation of patient biological response it would be necessary to investigate the function of at least the two main neuroendocrine structures involved in the neuroendocrine modulation of the immune responses, consisting of the hypothalamic-pituitary-adrenal axis and the pineal gland, since the lack of physiological circadian rhythm of cortisol and pineal hormone melatonin has appeared to be associated with a worse prognosis in the human systemic diseases.

Molecular subtypes of Alzheimer's disease.

Protein misfolding and aggregation is a central feature of several neurodegenerative disorders including Alzheimer's disease (AD), in which assemblies of amyloid ß (Aß) peptides accumulate in the brain in the form of parenchymal and/or vascular amyloid. A widely accepted concept is that AD is characterized by distinct clinical and neuropathological phenotypes. Recent studies revealed that Aß assemblies might have structural differences among AD brains and that such pleomorphic assemblies can correlate with distinct disease phenotypes. We found that in both sporadic and inherited forms of AD, amyloid aggregates differ in the biochemical composition of Aß species. These differences affect the physicochemical properties of Aß assemblies including aggregation kinetics, resistance to degradation by proteases and seeding ability. Aß-amyloidosis can be induced and propagated in animal models by inoculation of brain extracts containing aggregated Aß. We found that brain homogenates from AD patients with different molecular profiles of Aß are able to induce distinct patterns of Aß-amyloidosis when injected into mice. Overall these data suggest that the assembly of mixtures of Aß peptides into different Aß seeds leads to the formation of distinct subtypes of amyloid having distinctive physicochemical and biological properties which result in the generation of distinct AD molecular subgroups.

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

We developed a novel therapeutic strategy for Alzheimer's disease (AD) exploiting the properties of a natural variant of Amyloid-ß (Aß) carrying the A2V substitution, which protects heterozygous carriers from AD by its ability to interact with wild-type Aß, hindering conformational changes and assembly thereof. As prototypic compound we designed a six-mer mutated peptide (Aß1-6A2V), linked to the HIV-related TAT protein, which is widely used for brain delivery and cell membrane penetration of drugs. The resulting molecule [Aß1-6A2VTAT(D)] revealed strong anti-amyloidogenic effects in vitro and protected human neuroblastoma cells from Aß toxicity. Preclinical studies in AD mouse models showed that short-term treatment with Aß1-6A2VTAT(D) inhibits Aß 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 AßA2V-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 Aß1-6A2VTAT(D) was likely due to the TAT intrinsic attitude to increase Aß production, avidly bind amyloid and boost its seeding activity, warning against the use of the TAT carrier in the design of AD therapeutics.

Hereditary and sporadic beta-amyloidoses.

Cerebral amyloidoses are chronic, progressive neurodegenerative diseases that are caused by the aggregation and deposition of misfolded proteins in the central nervous system, and lead to cognitive deficits, stroke, and focal neurological dysfunction including cerebellar and extrapyramidal signs. Among them, beta-amyloidoses are a heterogenous set of conditions characterised by the deposition of beta-amyloid protein in brain parenchyma and/or vessel walls that lead to the development of two main clinico-pathological entities: Alzheimer's disease and cerebral amyloid angiopathy, which may be sporadic or familial, and may also co-exist in the same patient. The aim of this review is to describe the most important differences in the pathways leading to parenchymal and cerebrovascular beta-amyloidoses, and the main clinical, neuropathological and biochemical characteristics of the two conditions. It also discusses the phenotypes associated with a series of familial and sporadic beta-amyloidoses in more detail in order to highlight the clinical and neuropathological features that may help to distinguish the different forms of disease.

APP mutations in the Aß coding region are associated with abundant cerebral deposition of Aß38.

Aß is the main component of amyloid deposits in Alzheimer disease (AD) and its aggregation into oligomers, protofibrils and fibrils is considered a seminal event in the pathogenesis of AD. Aß with C-terminus at residue 42 is the most abundant species in parenchymal deposits, whereas Aß with C-terminus at residue 40 predominates in the amyloid of the walls of large vessels. Aß peptides with other C-termini have not yet been thoroughly investigated. We analysed Aß38 in the brains of patients with Aß deposition linked to sporadic and familial AD, hereditary cerebral haemorrhage with amyloidosis, or Down syndrome. Immunohistochemistry, confocal microscopy, immunoelectron microscopy, immunoprecipitation and the electrophoresis separation of low molecular weight aggregates revealed that Aß38 accumulates consistently in the brains of patients carrying APP mutations in the Aß coding region, but was not detected in the patients with APP mutations outside the Aß domain, in the patients with presenilin mutations or in subjects with Down syndrome. In the patients with sporadic AD, Aß38 was absent in the senile plaques, but it was detected only in the vessel walls of a small subset of patients with severe cerebral amyloid angiopathy. Our results suggest that APP mutations in the Aß coding region favour Aß38 accumulation in the brain and that the molecular mechanisms of Aß deposition in these patients may be different from those active in patients with familial AD associated with other genetic defects and sporadic AD.

Psychoneuroendocrine modulation of regulatory T lymphocyte system: in vivo and in vitro effects of the pineal immunomodulating hormone melatonin.

BACKGROUND: At present, it is known that cancer-related immunosuppression would mainly depend on an immunosuppressive action mediated by a subtype of CD4+ lymphocytes, the so-called regulatory T lymphocytes (T-reg), which are identified as CD4+CD25+ cells. Moreover, it has been shown that anticancer immunity is under psychoneuroendocrine regulation, mainly mediated by the pineal hormone melatonin (MLT). This study was performed to investigate the in vivo and in vitro effects of MLT on T-reg generation. MATERIALS AND METHODS: We evaluated the in vivo effects of MLT (20 mg/daily orally in the evening) in 20 patients with untreatable metastatic solid tumor and the in vitro effects of MLT incubation (at 10 and 100 pg/ml) of pure lymphocyte cultures on T-reg cell count. RESULTS: MLT induced a statistically significant decline in mean T-reg cell numbers in patients who achieved disease control, whereas no effect was seen in those who had progressed. In contrast, no in vitro effect of MLT incubation was apparent. CONCLUSION: This preliminary study would suggest that MLT may exert in vivo an inhibitory action on T-reg cell generation in cancer patients which is associated with a control of the neoplastic progression, whereas no direct effect was seen in vitro on lymphocyte differentiation. This finding would suggest that MLT may counteract T-reg cell generation in vivo by inhibiting macrophage activity which is involved in stimulating T-reg cell production.

Hereditary cerebral hemorrhage with amyloidosis associated with the E693K mutation of APP.

OBJECTIVE: To report the clinical, genetic, neuroimaging, and neuropathologic studies of patients with the hereditary cerebral hemorrhage with amyloidosis linked to the APP E693K mutation. DESIGN: Case series. Clinical details and laboratory results were collected by direct evaluation and previous medical records. DNA analysis was carried out in several affected subjects and healthy individuals. Neuropathologic examination was performed in 2 subjects. SETTING: Southern Lombardy, Italy. Patients Individuals with and without amyloidosis in 4 unrelated Italian families (N = 37). Main Outcome Measure Genotype-phenotype relationship. RESULTS: The affected individuals presented with recurrent headache and multiple strokes, followed by epilepsy and cognitive decline in most of them. The disease was inherited with an autosomal dominant trait and segregated with the APP E693K mutation. Neuroimaging demonstrated small to large hematomas, subarachnoid bleeding, scars with hemosiderin deposits, small infarcts, and leukoaraiosis. Amyloid-beta immunoreactivity was detected in the wall of leptomeningeal and parenchymal vessels and in the neuropil, whereas phosphorylated tau, neurofibrillary changes, and neuritic plaques were absent. CONCLUSIONS: These findings expand the number of APP mutations linked to hereditary cerebral hemorrhage with amyloidosis, reinforcing the link between this phenotype and codon 693 of APP.

Synchronization of cortisol circadian rhythm by the pineal hormone melatonin in untreatable metastatic solid tumor patients and its possible prognostic significance on tumor progression.

BACKGROUND: Cancer progression has been associated with neuroendocrine alterations involved in the control of the circadian rhythms, particularly those of cortisol. Moreover, the evidence of an altered cortisol rhythm may predict a poor prognosis in cancer patients. Finally, cancer progression has been proven to be associated with alterations in the pineal gland, which plays a fundamental role in the control of circadian biological rhythms. On this basis, a study was planned to evaluate the effects of a chronic treatment with the pineal hormone melatonin (MLT) in advanced cancer patients with altered cortisol circadian rhythm. PATIENTS AND METHODS: The study included 14 untreatable metastatic cancer patients showing alterations of cortisol rhythm. They were treated by MLT at 20 mg/day orally, in the evening, for 3 consecutive months. RESULTS: a normalization of cortisol rhythm was achieved in 4/14 (29%) patients. Moreover, stable disease (SD) was obtained in 6/14 (43%) patients under MLT therapy, whereas the other 8 patients had progressive disease (PD). Finally, the percentage of cortisol rhythm normalization achieved in patients with SD was significantly higher than that observed in patients with PD. CONCLUSION: These results show that MLT may normalize cortisol rhythm in advanced cancer patients and this effect appears to be associated with SD, thus confirming the negative prognostic significance of cortisol rhythm alterations in cancer.

Revelation of a new mitochondrial DNA mutation (G12147A) in a MELAS/MERFF phenotype.

BACKGROUND: A 26-year-old man presented at onset with the syndrome of mitochondrial encephalomyopathy, lactic acidosis, and strokelike episodes (MELAS) and later with a phenotype for MELAS and myoclonic epilepsy and ragged red fiber disease (MELAS/MERRF). OBJECTIVE: To identify the possible defects in the mitochondrial genome in blood and muscle samples of the patient. DESIGN: Case study of a patient clinically exhibiting strokelike episodes and then epilepsy with myoclonic features, ataxia, and dementia. SETTING: Research unit of a university hospital. MAIN OUTCOME MEASURES: Electromyographic, morphologic, and biochemical studies of muscle and molecular analysis of blood and muscle to investigate mitochondrial DNA (mtDNA) size and quantity. RESULTS: Morphologically, we found abnormal mitochondrial proliferation with several cytochrome-c oxidase (COX)-negative fibers in muscle biopsy specimens; the analysis of serial sections showed a decreased immunoreactivity for the mtDNA-encoded subunits COXII and, partially, COXI. Biochemically, we found a partial and isolated COX deficiency. The complete mtDNA sequence analysis identified 3 sequence changes, 2 of which were reported polymorphisms. The remaining change, a G12147A transition in the transfer RNA(His) gene, appeared to be the likely pathogenic mutation. CONCLUSIONS: Our data propose that the G12147A change, the first mutation in the transfer RNA(His) gene associated with an overlapped MELAS/MERFF phenotype, is the cause of the encephalomyopathy in this patient interfering with the overall mitochondrial protein synthesis.