Amiloidose renal familiar em cães da raça Shar-Pei / Family renal amyloidosis in Shar-Pei dogs / Amiloidosis renal familiar en perros Shar-Pei

A amiloidose renal familiar é uma doença incomum em cães, que afeta os rins e está associada ao acúmulo anormal de proteínas amiloides, com capacidade de promover danos orgânicos progressivos com comprometimento de funcionalidade. Caracterizada pela presença de conteúdo proteináceo glomerular, a amiloidose frequentemente está associada a quadros de falência renal, com presença de sinais clínicos variados, sendo uma condição grave e complexa. O presente artigo tem como objetivo descrever os achados clínico-laboratoriais, de imagem e histopatológicos de amiloidose familiar em dois cães da raça Shar-pei. Os animais apresentavam parentesco direto e evidenciavam sinais de cansaço, prostração e emagrecimento progressivo. As evidências clínico-laboratoriais e ultrassonográficas sugeriram a presença de glomerulonefropatia, sendo essa confirmada por exame histopatológico. Os dois cães, diante da gravidade do quadro, foram a óbito. A análise histopatológica evidenciou deposição de material proteináceo fibrilar na região glomerular e tubular, bem como infiltrado linfoplasmocítico, característicos de amiloidose renal. É essencial lembrar que a amiloidose renal familiar em cães é uma doença complexa e que as origens devem ser investigadas. O tratamento é desafiador, diante da inexistência de um manejo terapêutico definido para a doença, sendo este muitas vezes ineficaz. A empatia e o cuidado no manejo dessa condição podem ajudar a melhorar a qualidade de vida do paciente e fornecer conforto ao proprietário durante esse processo desafiador.

Family renal amyloidosis is an uncommon disease in dogs, which affects the kidneys and is associated with abnormal accumulation of amyloid proteins, capable of promoting progressive organic damage with impairment of functionality. Characterized by the presence of glomerular proteinaceous content, amyloidosis is often associated with renal failure, with the presence of varied clinical signs, being a serious and complex condition. This article aims to describe the clinical, laboratory, imaging and histopathological findings of familial amyloidosis in two Shar-pei dogs. The animals were directly related and evidenced signs of tiredness, prostration and progressive weight loss. Clinical, laboratory and ultrasonographic evidence suggested the presence of glomerulonephropathy, which was confirmed by histopathological examination. The two dogs, given the severity of the condition, died. Histopathological analysis showed deposition of fibrillar proteinaceous material in the glomerular and tubular region, as well as lymphoplasmocytic infiltrate, characteristic of renal amyloidosis. It is essential to remember that family renal amyloidosis in dogs is a complex disease and that the origins must be investigated. The treatment is challenging, given the lack of a defined therapeutic management for the disease, which is often ineffective. Empathy and care in managing this condition can help improve the patient's quality of life and provide comfort to the owner during this challenging process.

La amiloidosis renal familiar es una enfermedad poco común en perros, que afecta a los riñones y se asocia con la acumulación anormal de proteínas amiloides, con capacidad de promover daño orgánico progresivo con compromiso de la funcionalidad. Caracterizada por la presencia de contenido proteico glomerular, la amiloidosis suele asociarse a insuficiencia renal, con la presencia de signos clínicos variados, siendo una afección grave y compleja. El presente artículo tiene como objetivo describir los hallazgos clínico-laboratorios, imagenológicos e histopatológicos de la amiloidosis familiar en dos perros Sharpei. Los animales estaban directamente emparentados y presentaban signos de cansancio, postración y pérdida progresiva de peso. Los datos clínico-laboratorios y ecográficos sugirieron la presencia de glomerulonefropatía, la cual fue confirmada mediante examen histopatológico. Los dos perros, dada la gravedad del cuadro, fallecieron. El análisis histopatológico mostró depósito de material proteico fibrilar en la región glomerular y tubular, así como infiltrado linfoplasmocitario, característico de la amiloidosis renal. Es fundamental recordar que la amiloidosis renal familiar en perros es una enfermedad compleja y que es necesario investigar sus orígenes. El tratamiento es un desafío, dada la falta de un manejo terapéutico definido para la enfermedad, que muchas veces resulta ineficaz. La empatía y el cuidado en el manejo de esta afección pueden ayudar a mejorar la calidad de vida del paciente y brindar comodidad al propietario durante este desafiante proceso.

Long-term social isolation stress exacerbates sex-specific neurodegeneration markers in a natural model of Alzheimer's disease.

Social interactions have a significant impact on health in humans and animal models. Social isolation initiates a cascade of stress-related physiological disorders and stands as a significant risk factor for a wide spectrum of morbidity and mortality. Indeed, social isolation stress (SIS) is indicative of cognitive decline and risk to neurodegenerative conditions, including Alzheimer's disease (AD). This study aimed to evaluate the impact of chronic, long-term SIS on the propensity to develop hallmarks of AD in young degus (Octodon degus), a long-lived animal model that mimics sporadic AD naturally. We examined inflammatory factors, bioenergetic status, reactive oxygen species (ROS), oxidative stress, antioxidants, abnormal proteins, tau protein, and amyloid-ß (Aß) levels in the hippocampus of female and male degus that were socially isolated from post-natal and post-weaning until adulthood. Additionally, we explored the effect of re-socialization following chronic isolation on these protein profiles. Our results showed that SIS promotes a pro-inflammatory scenario more severe in males, a response that was partially mitigated by a period of re-socialization. In addition, ATP levels, ROS, and markers of oxidative stress are severely affected in female degus, where a period of re-socialization fails to restore them as it does in males. In females, these effects might be linked to antioxidant enzymes like catalase, which experience a decline across all SIS treatments without recovery during re-socialization. Although in males, a previous enzyme in antioxidant pathway diminishes in all treatments, catalase rebounds during re-socialization. Notably, males have less mature neurons after chronic isolation, whereas phosphorylated tau and all detectable forms of Aß increased in both sexes, persisting even post re-socialization. Collectively, these findings suggest that long-term SIS may render males more susceptible to inflammatory states, while females are predisposed to oxidative states. In both scenarios, the accumulation of tau and Aß proteins increase the individual susceptibility to early-onset neurodegenerative conditions such as AD.

Synaptic Mitochondria: An Early Target of Amyloid-ß and Tau in Alzheimer's Disease.

Alzheimer's disease (AD) is characterized by cognitive impairment and the presence of neurofibrillary tangles and senile plaques in the brain. Neurofibrillary tangles are composed of hyperphosphorylated tau, while senile plaques are formed by amyloid-ß (Aß) peptide. The amyloid hypothesis proposes that Aß accumulation is primarily responsible for the neurotoxicity in AD. Multiple Aß-mediated toxicity mechanisms have been proposed including mitochondrial dysfunction. However, it is unclear if it precedes Aß accumulation or if is a consequence of it. Aß promotes mitochondrial failure. However, amyloid ß precursor protein (AßPP) could be cleaved in the mitochondria producing Aß peptide. Mitochondrial-produced Aß could interact with newly formed ones or with Aß that enter the mitochondria, which may induce its oligomerization and contribute to further mitochondrial alterations, resulting in a vicious cycle. Another explanation for AD is the tau hypothesis, in which modified tau trigger toxic effects in neurons. Tau induces mitochondrial dysfunction by indirect and apparently by direct mechanisms. In neurons mitochondria are classified as non-synaptic or synaptic according to their localization, where synaptic mitochondrial function is fundamental supporting neurotransmission and hippocampal memory formation. Here, we focus on synaptic mitochondria as a primary target for Aß toxicity and/or formation, generating toxicity at the synapse and contributing to synaptic and memory impairment in AD. We also hypothesize that phospho-tau accumulates in mitochondria and triggers dysfunction. Finally, we discuss that synaptic mitochondrial dysfunction occur in aging and correlates with age-related memory loss. Therefore, synaptic mitochondrial dysfunction could be a predisposing factor for AD or an early marker of its onset.

Human serum proteins bind to Sporothrix schenckii conidia with differential effects on phagocytosis.

Serum is an important source of proteins that interact with pathogens. Once bound to the cell surface, serum proteins can stimulate the innate immune system. The phagocytosis of Sporothrix schenckii conidia by human macrophages is activated through human serum opsonisation. In this study, we have attempted to characterise human blood serum proteins that bind to the cell wall of S. schenckii conidia. We systematically observed the same four proteins independent of the plasma donor: albumin, serum amyloid protein (SAP), α-1 antitrypsin (AAT), and transferrin were identified with the help of tandem mass spectrometry. Phagocytosis depended on the concentration of the SAP or α-1 antitrypsin that was used to opsonise the conidia; however, transferrin or albumin did not have any effect on conidia internalisation. The presence of mannose did not affect macrophage phagocytosis of the conidia opsonised with SAP or α-1 antitrypsin, which suggests that these proteins are not recognised by the mannose receptor.

Age-Dependent Decline in Synaptic Mitochondrial Function Is Exacerbated in Vulnerable Brain Regions of Female 3xTg-AD Mice.

Synaptic aging has been associated with neuronal circuit dysfunction and cognitive decline. Reduced mitochondrial function may be an early event that compromises synaptic integrity and neurotransmission in vulnerable brain regions during physiological and pathological aging. Thus, we aimed to measure mitochondrial function in synapses from three brain regions at two different ages in the 3xTg-AD mouse model and in wild mice. We found that aging is the main factor associated with the decline in synaptic mitochondrial function, particularly in synapses isolated from the cerebellum. Accumulation of toxic compounds, such as tau and Aß, that occurred in the 3xTg-AD mouse model seemed to participate in the worsening of this decline in the hippocampus. The changes in synaptic bioenergetics were also associated with increased activation of the mitochondrial fission protein Drp1. These results suggest the presence of altered mechanisms of synaptic mitochondrial dynamics and their quality control during aging and in the 3xTg-AD mouse model; they also point to bioenergetic restoration as a useful therapeutic strategy to preserve synaptic function during aging and at the early stages of Alzheimer's disease (AD).

Hemorrhagic stroke and COVID-19 infection: Coincidence or causality?

Amyloid Protein Precursor gene duplication is a rare cause of early-onset Alzheimer's disease that can be associated with Cerebral Amyloid Angiopathy. This condition predisposes cerebrovascular events, specifically, intracerebral hemorrhagic stroke. This report describes a case of first-time intracerebral hemorrhage in a patient with APP gene duplication during SARS-CoV-2 infection, a typically pro-thrombotic and pro-inflammatory condition, as a possible trigger for this condition.

Control of microbial biofilm formation as an approach for biomaterials synthesis.

The search for new biomaterials with superior mechanical properties is the focus in the area of materials science. A promising pathway is drawing inspiration from nature to design and develop materials with enhanced properties. In this work, a novel strategy to produce functionalized supramolecular bionanomaterials from the microbial biofilm is reported. Tuneable biofilms with specific characteristics were obtained by controlling the culture condition of the microorganism. When the exopolysaccharide (EPS) production was desired the tryptone was the best nutritional component for the EPS production into the biofilm. However, for the expression of a high amount of amyloid protein the combination of peptone and glucose was the best nutritional choice. Each biofilm obtained showed its owner rheology properties. These properties were altered by the addition of extracellular DNA, which increased the viscosity of the biofilm and induced a viscoelastic hydrogel behavior. Besides, as a proof of concept of bionanomaterial, a novel supramolecular polymeric hybrid EPS-Amyloid protein (EPAP) was obtained from the biofilm and it was tested as a new natural functionalized support for enzyme immobilization. The results suggest that this technology could be used as a new concept to obtain biomaterials from biofilms by controlling the nutritional conditions of a microorganism. Understanding environmental factors affecting biofilm formation will help the development of methods for controlling biofilm production and therefore obtaining new biomaterials.

Chlorella sorokiniana and Chlorella minutissima exhibit antioxidant potentials, inhibit cholinesterases and modulate disaggregation of ß-amyloid fibrils

BACKGROUND: Microalgae are aquatic chlorophyll-containing organisms comprising unicellular microscopic forms, and their biomasses are potential sources of bioactive compounds, biofuels and food-based products. However, the neuroprotective effects of microalgal biomass have not been fully explored. In this study, biomass from two Chlorella species was characterized, and their antioxidant, anticholinesterase and anti-amyloidogenic activities were investigated. RESULTS: GC­MS analysis of the extracts revealed the presence of some phenols, sterols, steroids, fatty acids and terpenes. Ethanol extract of Chlorella sorokiniana (14.21 mg GAE/g) and dichloromethane extract of Chlorella minutissima (20.65 mg QE/g) had the highest total phenol and flavonoid contents, respectively. All the extracts scavenged 2,2-diphenyl-1-picrylhydrazyl, 2,2-azinobis (3-ethylbenzothiazoline-6-sulfonate) and hydroxyl radicals. The highest metal chelating activity of the extracts was observed in the ethanol extracts of C. minutissima (102.60 µg/mL) and C. sorokiniana (107.84 µg/mL). Furthermore, the cholinesterase inhibitory activities of the extracts showed that ethanol extract of C. sorokiniana (13.34 µg/mL) exhibited the highest acetylcholinesterase inhibitory activity, while dichloromethane extract of C. minutissima (11.78 µg/mL) showed the highest butyrylcholinesterase inhibitory activity. Incubation of the ß-amyloid protein increased the aggregation of amyloid fibrils after 96 h. However, ethanol extract of C. sorokiniana and C. minutissima inhibited further aggregation of Aß1­42 and caused disaggregation of matured protein fibrils compared to the control. This study reveals the modulatory effects of C. sorokiniana and C. minutissima extracts on some mediators of Alzheimer's disease and provides insights into their potential benefits as functional food, nutraceutics or therapeutic agent for the management of this neurodegenerative disease.

CSF Aß1-42, but not p-Tau181, Predicted Progression from Amnestic MCI to Alzheimer's Disease Dementia.

The purpose of the study was to determine whether Aß1-42 and p-Tau181 cerebral spinal fluid (CSF) levels can predict progression from amnestic mild cognitive impairment (aMCI) to Alzheimer's disease dementia (ADD) in a 3-year follow-up study. All participants were evaluated blindly by a behavioral neurologist and a neuropsychologist, and classified according to the Petersen criteria for aMCI and according to the Clinical Dementia Rating (CDR) scale. Individuals were also submitted to lumbar puncture at baseline. Levels of Aß1-42 and p-Tau181 were measured by immunoenzymatic assay. Values were adjusted for age and sex. Thirty-one of 33 (93.9%) participants completed follow-up. Approximately 39% of aMCI individuals progressed to ADD. The relative risk of developing ADD in those with Aß1-42 CSF levels lower than 618.5 pg/mL was 17.4 times higher than in those whose levels were higher than 618.5 pg/mL (P = 0.003). p-Tau181 alone did not predict progression to ADD (P = 0.101). The relative risk in those with a p-Tau181/Aß1-42 ratio higher than 0.135 was 5.7 times greater (P < 0.001). Aß1-42 and p-Tau181 explained 40.1% of the verbal memory test subscore of the Consortium to Establish a Registry for Alzheimer's Disease (ΔCERADs) variance (P = 0.008). Aß1-42 strongly predicted progression from aMCI to ADD. p-Tau181 alone, or its relation to Aß1-42, was inferior than Aß1-42 alone as a predictor of progression to ADD.

Tolfenamic Acid Prevents Amyloid ß-induced Olfactory Bulb Dysfunction In Vivo.

BACKGROUND: Amyloid beta inhibits olfactory bulb function. The mechanisms involved in this effect must include alterations in network excitability, inflammation and the activation of different transduction pathways. Thus, here we tested whether tolfenamic acid, a drug that modulates several of these pathological processes, could prevent amyloid beta-induced olfactory bulb dysfunction. OBJECTIVE: To test whether tolfenamic acid prevents amyloid beta-induced alterations in olfactory bulb network function, olfaction and GSK3ß activity. METHOD: The protective effects of tolfenamic acid against amyloid beta-induced population activity inhibition were tested in olfactory bulb slices from adult mice, while tolfenamic acid and amyloid beta were bath-applied. We also tested the effects of amyloid-beta in slices obtained from animals pre-treated chronically (21 days) with tolfenamic acid. The effects of amyloid beta micro-injected into the olfactory bulbs were also tested, after two weeks, on olfactory bulb population activity and olfaction in control and tolfenamic acid chronically treated animals. Olfaction was assessed with the odor-avoidance and the habituation/cross-habituation tests. GSK3ß activation was evaluated with Western-blot. RESULTS: Acute bath application of tolfenamic acid does not prevent amyloid beta-induced inhibition of olfactory bulb network activity in vitro. In contrast, chronic treatment with tolfenamic acid renders the olfactory bulb resistant to amyloid beta-induced network activity inhibition in vitro and in vivo, which correlates with the inhibition of GSK3ß activation and the protection against amyloid beta-induced olfactory dysfunction. CONCLUSION: Our data further support the use of tolfenamic acid to prevent amyloid beta-induced pathology and the early symptoms of Alzheimer Disease.

Leptin in Alzheimer's disease.

Alzheimer's disease (AD) is the most common cause of progressive dementia in the elderly population. AD is histologically characterized by accumulation of amyloid-ß protein (Aß) on extracellular plaques and deposition of hyperphosphorylated tau protein in intracellular neurofibrillary tangles. Several studies have shown that obesity may precede dementia and that lifestyle factors play a critical role in the onset of AD. Furthermore, accumulating evidence indicates that obesity is an independent risk factor for developing AD. In this scenario, the understanding of the role of adipose tissue in brain health is essential to clarify the establishment of demential processes. The objective of this work was to review studies regarding leptin, an anorexigenic peptide hormone synthesized in adipocytes, in the context of dementia. Some authors proposed that leptin evaluation might be a better predictor of dementia than traditional anthropometric measures. Leptin, once established as a biomarker, could enhance the understanding of late-onset AD risk over the life course, as well as the clinical progression of prodromal state to manifested AD. Other studies have proposed that leptin presents neuroprotective activities, which could be explained by inhibiting the amyloidogenic process, reducing the levels of tau protein phosphorylation and improving the cognitive function.

Mild cognitive impairment (part 2): biological markers for diagnosis and prediction of dementia in Alzheimer's disease

Objective: To present a critical review of publications reporting on the rationale and clinical implications of the use of biomarkers for the early diagnosis of Alzheimer's disease (AD). Methods: We conducted a systematic search of the PubMed and Web of Science electronic databases, limited to articles published in English between 1999 and 2012, and based on the following terms: mild cognitive impairment, Alzheimer's disease OR dementia, biomarkers. We retrieved 1,130 articles, of which 175 were reviews. Overall, 955 original articles were eligible. Results: The following points were considered relevant for the present review: a) rationale for biomarkers research in AD and mild cognitive impairment (MCI); b) usefulness of distinct biomarkers for the diagnosis and prediction of AD; c) the role of multimodality biomarkers for the diagnosis and prediction of AD; d) the role of biomarkers in clinical trials of patients with AD and MCI; and e) current limitations to the widespread use of biomarkers in research and clinical settings. Conclusion: Different biomarkers are useful for the early diagnosis and prediction of AD in at-risk subjects. Nonetheless, important methodological limitations need to be overcome for widespread use of biomarkers in research and clinical settings. .