Monitoring the interactions between POPG phospholipid bilayer and amyloid-forming protein human cystatin C. Does the bilayer influence the oligomeric state and structure of the protein?

A biological membrane is a structure characteristic for various cells and organelles present in almost all living organisms. Even though, it is one of the most common structures in organisms, where it serves crucial functions, a phospholipid bilayer may also take part in pathological processes leading to severe diseases. Research indicates that biological membranes have a profound impact on the pathological processes of oligomerization of amyloid-forming proteins. These processes are a hallmark of amyloid diseases, a group of pathological states involving, e.g., Parkinson's or Alzheimer's disease. Even though amyloidogenic diseases reap the harvest in modern societies, especially in elderly patients, the mechanisms governing the amyloid deposition are not clearly described. Therefore, the presented study focuses on the description of interactions between a model biological membrane (POPG) and one of amyloid forming proteins - human cystatin C. For the purpose of the study molecular dynamics simulations were applied to confirm interactions between the protein and POPG membrane. Next the NMR techniques were used to verify how the data obtained in solution compared to MD simulations and determine fragments of the protein responsible for interactions with POPG. Finally, circular dichroism was used to monitor the changes in secondary structure of the protein and size exclusion chromatography was used to monitor its oligomerization process. Obtained data indicates that the protein interacts with POPG submerging itself into the bilayer with the AS region. However, the presence of POPG bilayer does not significantly affect the structure or oligomerization process of human cystatin C.

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.

Atomic Insights into Amyloid-Induced Membrane Damage.

Amphipathic peptides can cause biological membranes to leak either by dissolving their lipid content via a detergent-like mechanism or by forming pores on the membrane surface. These modes of membrane damage have been related to the toxicity of amyloid peptides and to the activity of antimicrobial peptides. Here, we perform the first all-atom simulations in which membrane-bound amphipathic peptides self-assemble into ß-sheets that subsequently either form stable pores inside the bilayer or drag lipids out of the membrane surface. An analysis of these simulations shows that the acyl tail of lipids interact strongly with non-polar side chains of peptides deposited on the membrane. These strong interactions enable lipids to be dragged out of the bilayer by oligomeric structures accounting for detergent-like damage. They also disturb the orientation of lipid tails in the vicinity of peptides. These distortions are minimized around pore structures. We also show that membrane-bound ß-sheets become twisted with one of their extremities partially penetrating the lipid bilayer. This allows peptides on opposite leaflets to interact and form a long transmembrane ß-sheet, which initiates poration. In simulations, where peptides are deposited on a single leaflet, the twist in ß-sheets allows them to penetrate the membrane and form pores. In addition, our simulations show that fibril-like structures produce little damage to lipid membranes, as non-polar side chains in these structures are unavailable to interact with the acyl tail of lipids.

The localization of amyloid precursor protein to ependymal cilia in vertebrates and its role in ciliogenesis and brain development in zebrafish.

Amyloid precursor protein (APP) is expressed in many tissues in human, mice and in zebrafish. In zebrafish, there are two orthologues, Appa and Appb. Interestingly, some cellular processes associated with APP overlap with cilia-mediated functions. Whereas the localization of APP to primary cilia of in vitro-cultured cells has been reported, we addressed the presence of APP in motile and in non-motile sensory cilia and its potential implication for ciliogenesis using zebrafish, mouse, and human samples. We report that Appa and Appb are expressed by ciliated cells and become localized at the membrane of cilia in the olfactory epithelium, otic vesicle and in the brain ventricles of zebrafish embryos. App in ependymal cilia persisted in adult zebrafish and was also detected in mouse and human brain. Finally, we found morphologically abnormal ependymal cilia and smaller brain ventricles in appa-/-appb-/- mutant zebrafish. Our findings demonstrate an evolutionary conserved localisation of APP to cilia and suggest a role of App in ciliogenesis and cilia-related functions.

Combined Subcutaneous Fat Aspirate and Skin Tru-Cut Biopsy for Amyloid Screening in Patients with Suspected Systemic Amyloidosis.

Screening for systemic amyloidosis is typically carried out with abdominal fat aspirates with varying reported sensitivities. Fat aspirates are preferred for use in primary screening instead of organ biopsies as they are less invasive and thereby minimize the potential risk of complications. At Odense Amyloidosis Center, we performed a prospective study on whether the combined use of fat aspirate and tru-cut skin biopsy could increase the diagnostic sensitivity. Both fat aspirates and skin biopsies were screened with Congo Red staining, and positive biopsies were subsequently subtyped using immunoelectron microscopy and mass spectrometry. Seventy-six patients were included. In total, 24 patients had systemic amyloidosis (11 AL, 12 wtATTR, 1 AA), and 6 patients had localized amyloidosis. Combined fat aspirate and skin biopsy were Congo Red-positive in 15 patients (overall sensitivity (OS) 62.5%). Fat aspirates were positive in 14 patients (OS 58.3%), and the skin biopsy was positive in 5 patients (OS 20.8%). In only one patient did the skin biopsy add extra diagnostic information. The sensitivity differed between AL and ATTR amyloidosis-81.8% and 41.7%, respectively. Using skin biopsy as the only screening method is not recommended.

MALDI mass spectrometry imaging unravels organ and amyloid-type specific peptide signatures in pulmonary and gastrointestinal amyloidosis.

PURPOSE: Amyloidosis is a disease group caused by pathological aggregation and deposition of peptides in diverse tissue sites. Recently, matrix-assisted laser desorption/ionization mass spectrometry imaging coupled with ion mobility separation (MALDI-IMS MSI) was introduced as a novel tool to identify and classify amyloidosis using single sections from formalin-fixed and paraffin-embedded cardiac biopsies. Here, we tested the hypothesis that MALDI-IMS MSI can be applied to lung and gastrointestinal specimens. EXPERIMENTAL DESIGN: Forty six lung and 65 gastrointestinal biopsy and resection specimens with different types of amyloid were subjected to MALDI-IMS MSI. Ninety three specimens included tissue areas without amyloid as internal negative controls. Nine cases without amyloid served as additional negative controls. RESULTS: Utilizing a peptide filter method and 21 known amyloid specific tryptic peptides we confirmed the applicability of a universal peptide signature with a sensitivity of 100% and a specificity of 100% for the detection of amyloid deposits in the lung and gastrointestinal tract. Additionally, the frequencies of individual m/z-values of the 21 tryptic marker peptides showed organ- and tissue-type specific differences. CONCLUSIONS AND CLINICAL RELEVANCE: MALDI-IMS MSI adds a valuable analytical approach to diagnose and classify amyloid and the detection frequency of individual tryptic peptides is organ-/tissue-type specific.

Amyloid PET Imaging in Self-Identified Non-Hispanic Black Participants of the Anti-Amyloid in Asymptomatic Alzheimer's Disease (A4) Study.

OBJECTIVE: To examine whether amyloid PET in cognitively normal (CN) individuals screened for the Anti-Amyloid in Asymptomatic Alzheimer's Disease (A4) study differed across self-identified non-Hispanic White and Black (NHW and NHB) groups. METHODS: We examined 3,689 NHW and 144 NHB participants who passed initial screening for the A4 study and underwent amyloid PET. The effect of race on amyloid PET was examined using logistic (dichotomous groups) and linear (continuous values) regression controlling for age, sex, and number of APOE ε4 and APOE ε2 alleles. Associations between amyloid and genetically determined ancestry (reflecting African, South Asian, East Asian, American, and European populations) were tested within the NHB group. Potential interactions with APOE were assessed. RESULTS: NHB participants had lower rates of amyloid positivity and lower continuous amyloid levels compared to NHW participants. This race effect on amyloid was strongest in the APOE ε4 group. Within NHB participants, those with a lower percentage of African ancestry had higher amyloid. A greater proportion of NHB participants did not pass initial screening compared to NHW participants, suggesting potential sources of bias related to race in the A4 PET data. CONCLUSION: Reduced amyloid was observed in self-identified NHB participants who passed initial eligibility criteria for the A4 study. This work stresses the importance of investigating AD biomarkers in ancestrally diverse samples as well as the need for careful consideration regarding study eligibility criteria in AD prevention trials.

Diagnosis of amyloid beyond Congo red.

PURPOSE OF REVIEW: Amyloidoses are a group of rare and heterogeneous diseases in which abnormally folded proteins deposit in tissues and lead to organ damage. A brief review of advances in the diagnosis of extracerebral systemic amyloidoses in the context of recent advances in their clinical management is provided. RECENT FINDINGS: Although steady progress in the treatment of AL and AA has evolved over many years, significant advances in the treatment of ATTR, transthyretin-derived amyloidosis, have been achieved only recently. This coincides with the emergence of nontissue diagnosis of cardiac ATTR in both the hereditary and wild-type settings. The latter is emerging as possibly the most prevalent type of systemic amyloidosis.Available treatments are amyloid protein type dependent and, hence, following amyloid detection, amyloid protein typing is necessary. Although mass spectrometry has emerged as the preferred method of amyloid typing, careful application of immune methods is still clinically useful but caution and experience, as well as awareness of the limitations of each method, are necessary in their interpretation. SUMMARY: Despite significant advances in the treatment of the systemic amyloidoses, outcomes remain poor, primarily due to delays in diagnosis. Precise diagnosis of the amyloid protein type is critical for treatment selection.

Mass spectrometry-based absolute quantification of amyloid proteins in pathology tissue specimens: Merits and limitations.

To clarify the significance of quantitative analyses of amyloid proteins in clinical practice and in research relating to systemic amyloidoses, we applied mass spectrometry-based quantification by isotope-labeled cell-free products (MS-QBIC) to formalin-fixed, paraffin-embedded (FFPE) tissues. The technique was applied to amyloid tissues collected by laser microdissection of Congo red-stained lesions of FFPE specimens. Twelve of 13 amyloid precursor proteins were successfully quantified, including serum amyloid A (SAA), transthyretin (TTR), immunoglobulin kappa light chain (IGK), immunoglobulin lambda light chain (IGL), beta-2-microglobulin (B2M), apolipoprotein (Apo) A1, Apo A4, Apo E, lysozyme, Apo A2, gelsolin, and fibrinogen alpha chain; leukocyte cell-derived chemotaxin-2 was not detected. The quantification of SAA, TTR, IGK, IGL, and B2M confirmed the responsible proteins, even when the immunohistochemical results were not decisive. Considerable amounts of Apo A1, Apo A4, and Apo E were deposited in parallel amounts with the responsible proteins. Quantification of amyloid protein by MS-QBIC is feasible and useful for the classification of and research on systemic amyloidoses.

Towards an improved early diagnosis of neurodegenerative diseases: the emerging role of in vitro conversion assays for protein amyloids.

Tissue accumulation of abnormal aggregates of amyloidogenic proteins such as prion protein, α-synuclein, and tau represents the hallmark of most common neurodegenerative disorders and precedes the onset of symptoms by years. As a consequence, the sensitive and specific detection of abnormal forms of these proteins in patients' accessible tissues or fluids as biomarkers may have a significant impact on the clinical diagnosis of these disorders. By exploiting seeded polymerization propagation mechanisms to obtain cell-free reactions that allow highly amplified detection of these amyloid proteins, novel emerging in vitro techniques, such as the real-time quaking-induced conversion assay (RT-QuIC) have paved the way towards this important goal. Given its high accuracy in identifying misfolded forms of prion protein from Creutzfeldt-Jakob disease (CJD) CSF, RT-QuIC has already been included in the diagnostic criteria for the clinical diagnosis of sporadic CJD, the most common human prion disease. By showing that this assay may also accurately discriminate between Lewy body disorders and other forms of parkinsonisms or dementias, more recent studies strongly suggested that CSF RT-QuIC can also be successfully applied to synucleinopathies. Finally, preliminary encouraging data also suggested that CSF RT-QuIC might also work for tau protein, and accurately distinguish between 3R- and 4R tauopathies, including Pick's disease, progressive supranuclear palsy, and corticobasal degeneration. Here we will review the state of the art of cell-free aggregation assays, their current diagnostic value and putative limitations, and the future perspectives for their expanded use in clinical practice.

Diagnostic amyloid proteomics: experience of the UK National Amyloidosis Centre.

Systemic amyloidosis is a serious disease which is caused when normal circulating proteins misfold and aggregate extracellularly as insoluble fibrillary deposits throughout the body. This commonly results in cardiac, renal and neurological damage. The tissue target, progression and outcome of the disease depends on the type of protein forming the fibril deposit, and its correct identification is central to determining therapy. Proteomics is now used routinely in our centre to type amyloid; over the past 7 years we have examined over 2000 clinical samples. Proteomics results are linked directly to our patient database using a simple algorithm to automatically highlight the most likely amyloidogenic protein. Whilst the approach has proved very successful, we have encountered a number of challenges, including poor sample recovery, limited enzymatic digestion, the presence of multiple amyloidogenic proteins and the identification of pathogenic variants. Our proteomics procedures and approaches to resolving difficult issues are outlined.

Detection of Alzheimer Disease Pathology in Patients Using Biochemical Biomarkers: Prospects and Challenges for Use in Clinical Practice.

BACKGROUND: Thirty-four years ago, amyloid-ß 1-42 peptide was identified in amyloid plaques from brain tissue obtained from patients with Alzheimer disease (AD) and Down syndrome. This finding led to development of immunoassays for this marker of amyloid plaque burden in cerebrospinal fluid (CSF) approximately 10 years later. Subsequently, research immunoassays were developed for total τ protein and τ phosphorylated at the threonine 181 position. Subsequent studies documented the clinical utility of these biomarkers of amyloid plaque burden or τ tangle pathology in cohorts of living patients. CONTENT: We describe the following: (a) clinical utility of AD biomarkers; (b) measurement challenges, including development of mass spectrometry-based reference methods and automated immunoassays; (c) development of "appropriate use criteria" (AUC) guidelines for safe/appropriate use of CSF testing for diagnosis of AD developed by neurologists, a neuroethicist, and laboratorians; (d) a framework, sponsored by the National Institute of Aging-Alzheimer's Association (NIA-AA), that defines AD on the basis of CSF and imaging methods for detecting amyloid plaque burden, τ tangle pathology, and neurodegeneration. This framework's purpose was investigative but has important implications for future clinical practice; (e) recognition of copathologies in AD patients and challenges for developing methods to detect these in living patients. SUMMARY: The field can expect availability of validated research tools for detection of AD pathology that support clinical treatment trials of disease-modifying agents and, ultimately, use in clinical practice. Validated methods are becoming available for CSF testing; emergence of validated methods for AD biomarkers in plasma can be expected in the next few years.

Interrogating Amyloid Aggregates using Fluorescent Probes.

Amyloids are a broad class of proteins and peptides that can misfold and assemble into long unbranched fibrils with a cross-ß conformation. These misfolding and aggregation events are associated with the onset of a variety of human diseases, among them, Alzheimer's disease, Parkinson's disease, and Huntington disease. Our understanding of amyloids has been greatly supported by fluorescent molecular probes, such as thioflavin-T, which shows an increase in fluorescence emission upon binding to fibrillar aggregates. Since the first application of thioflavin-T in amyloid studies nearly 30 years ago, many probes have emerged exhibiting a variety of responses to amyloids, such as intensity changes, shifts in fluorescence maxima, and variations in lifetimes, among many others. These probes have shed light on a variety of topics including the kinetics of amyloid aggregation, the effectiveness of amyloid aggregation inhibitors, the elucidation of binding sites in amyloid structures, and the staining of amyloids aggregates in vitro, ex vivo, and in vivo. In this Review, we discuss the design, properties, and application of photoactive probes used to study amyloid aggregation, as well as the challenges faced by current probes and techniques, and the novel approaches that are emerging to address these challenges.

Conformational Evolution of Molecular Signatures during Amyloidogenic Protein Aggregation.

Aggregation is a pathological hallmark of proteinopathies such as Alzheimer's disease and results in the deposition of ß-sheet-rich amyloidogenic protein aggregates. Such proteinopathies can be classified by the identity of one or more aggregated proteins, with recent evidence also suggesting that distinct molecular conformers (strains) of the same protein can be observed in different diseases, as well is in subtypes of the same disease. Therefore, methods for the quantification of pathological changes in protein conformation are central to understanding and treating proteinopathies. In this work, the evolution of Raman spectroscopic molecular signatures of three conformationally distinct proteins, bovine serum albumin (α-helical-rich), ß2-microglobulin (ß-sheet-rich), and tau (natively disordered), was assessed during aggregation into oligomers and fibrils. The morphological evolution was tracked using atomic force microscopy and corresponding conformational changes were assessed by their Raman signatures acquired in both wet and dried conditions. A deconvolution model was developed which allowed us to quantify the conformation of the nonregular protein tau, as well as for the oligomeric and fibrillar species of each of the proteins. Principle component analysis of the fingerprint region allowed further identification of the distinguishing spectral features and unsupervised distinction. While an increase in ß-sheet is seen on aggregation, crucially, however, each protein also retains a significant proportion of its native monomeric structure after aggregation. Thus, spectral analysis of each aggregated species, oligomeric, as well as fibrillar, for each protein resulted in a unique and quantitative "conformational fingerprint". This approach allowed us to provide the first differential detection of both oligomers and fibrils of the three different amyloidogenic proteins, including tau, whose aggregates have never before been interrogated using spontaneous Raman spectroscopy. Quantitative "conformational fingerprinting" by Raman spectroscopy thus demonstrates its huge potential and utility in understanding proteinopathic disease mechanisms and for providing strain-specific early diagnostic markers and targets for disease-modifying therapies.

A new approach for the separation, characterization and testing of potential prionoid protein aggregates through hollow-fiber flow field-flow fractionation and multi-angle light scattering.

Protein misfolding and aggregation are the common mechanisms in a variety of aggregation-dependent diseases. The compromised proteins often assemble into toxic, accumulating amyloid-like structures of various lengths and their toxicity can also be transferred both in vivo and in vitro a prion-like behavior. The characterization of protein interactions, degradation and conformational dynamics in biological systems still represents an analytical challenge in the prion-like protein comprehension. In our work, we investigated the nature of a transferable cytotoxic agent, presumably a misfolded protein, through the coupling of a multi-detector, non-destructive separation platform based on hollow-fiber flow field-flow fractionation with imaging and downstream in vitro tests. After purification with ion exchange chromatography, the transferable cytotoxic agentwas analyzed with Atomic Force Microscopy and statistical analysis, showing that the concentration of protein dimers and low n-oligomer forms was higher in the cytotoxic sample than in the control preparation. To assess whether the presence of these species was the actual toxic and/or self-propagating factor, we employed HF5 fractionation, with UV and Multi-Angle Light Scattering detection, to define proteins molar mass distribution and abundance, and fractionate the sample into size-homogeneous fractions. These fractions were then tested individually in vitro to investigate the direct correlation with cytotoxicity. Only the later-eluted fraction, which contains high-molar mass aggregates, proved to be toxic onto cell cultures. Moreover, it was observed that the selective transfer of toxicity also occurs for one lower-mass fraction, suggesting that two different mechanisms, acute and later induced toxicity, are in place. These results strongly encourage the efficacy of this platform to enable the identification of protein toxicants.

Lower respiratory tract amyloidosis: Presentation, survival and prognostic factors. A multicenter consecutive case series.

Lower-respiratory-tract (LRT) amyloidosis has rarely been investigated. Our study presents characteristics, outcomes and survival of LRT amyloidosis. This multicenter retrospective study, from 1995 to 2017, included 73 patients with amyloidosis and LRT involvement. Respiratory patterns were: tracheobronchial (n = 17), nodular (n = 10), interstitial (n = 14) or composite (several respiratory involvements, n = 32). Interstitial and composite patterns were associated with multi-organ amyloidosis (n = 37, 80%) while tracheobronchial and nodular patterns were associated with organ-limited amyloidosis (n = 21, 78%). Amyloid light chain (AL) amyloidosis was diagnosed in 43 patients (59%), mainly of lambda type (n = 33, 77%). Smokers' proportion was higher in tracheobronchial (71%) and nodular (90%) patterns than in interstitial (14%) and composite (34%) patterns. The B-cell neoplasms involved 15 patients (21%), solid neoplasms 8 (11%), connective tissue diseases 8 (11%) and multiple myeloma 6 (8%). The B-cell and solid neoplasms were most prevalent in nodular pattern. Median follow-up was 4.4 years (2.2-8.9). Twenty-four patients died, mostly from respiratory infection. Survival at 1, 5, 10 years was respectively 88%, 70% and 54% for multi-organ amyloidosis, 96%, 89% and 69% for organ-limited amyloidosis (P = .125). Tracheobronchial and nodular patterns survival was better than in other respiratory patterns (P = .039). Death risk factors (multivariate analysis) were: cardiac localization (hazard-ratio [HR] 4.3 [95% confidence interval 1.6-11.5]; P = .004), age (HR 2.1 [1.2-3.7]; P = .008) and dyspnea at diagnosis (HR 4.0 [1.3-12.3]; P = .014). Various LRT amyloidosis patterns depend on smoking habits, organ-limited or multi-organ extension and comorbidities. They are associated with a different survival, which is also predicted by age, cardiac localization and dyspnea at presentation.

Neuroimaging Biomarkers for Alzheimer's Disease.

Currently, over five million Americans suffer with Alzheimer's disease (AD). In the absence of a cure, this number could increase to 13.8 million by 2050. A critical goal of biomedical research is to establish indicators of AD during the preclinical stage (i.e. biomarkers) allowing for early diagnosis and intervention. Numerous advances have been made in developing biomarkers for AD using neuroimaging approaches. These approaches offer tremendous versatility in terms of targeting distinct age-related and pathophysiological mechanisms such as structural decline (e.g. volumetry, cortical thinning), functional decline (e.g. fMRI activity, network correlations), connectivity decline (e.g. diffusion anisotropy), and pathological aggregates (e.g. amyloid and tau PET). In this review, we survey the state of the literature on neuroimaging approaches to developing novel biomarkers for the amnestic form of AD, with an emphasis on combining approaches into multimodal biomarkers. We also discuss emerging methods including imaging epigenetics, neuroinflammation, and synaptic integrity using PET tracers. Finally, we review the complementary information that neuroimaging biomarkers provide, which highlights the potential utility of composite biomarkers as suitable outcome measures for proof-of-concept clinical trials with experimental therapeutics.

Síndrome do túnel do carpo associada à amiloidose / Carpal tunnel syndrome associated with amyloidosis

Introdução: A amiloidose é caracterizada pela deposição de proteínas nos órgãos e tecidos, e tem sido associada à síndrome do túnel do carpo (STC) quando ocorre no punho. O objetivo é descrever uma série de casos de pacientes submetidos à cirurgia para STC associado à amiloidose. Métodos: O estudo incluiu 12 pacientes que se submeteram à cirurgia para tratar a STC cuja biópsia identificou amiloidose; o seguimento foi de cinco anos. Os pacientes foram avaliados por testes clínicos, eletroneuromiografia, imagens radiológicas e biópsia. Resultados: Todos os pacientes apresentaram queixas musculoesqueléticas, sintomas severos de compressão do nervo mediano, alterações nos testes neurofisiológicos. Realizou-se a cirurgia, sinovectomia e biópsia. No pós-operatório, cinco pacientes (41%) desenvolveram dor crônica e distrofia simpático-reflexa. Conclusão: Observou-se maior frequência de dor pós-operatória na amostra, o que revela a necessidade de atenção na abordagem e tratamento dessa associação.

Introduction: Amyloidosis features protein deposition in the organs and tissues and has been associated with carpal tunnel syndrome (CTS) when it occurs in the wrist. The objective is to describe a case series of patients undergoing surgery for CTS associated with amyloidosis. Methods: The study included 12 patients who underwent surgery to treat CTS in whom amyloidosis was proven by biopsy; the follow-up period was 5 years. The patients were evaluated by clinical tests, electroneuromyography, radiological images, and biopsy. Results: All patients presented with musculoskeletal complaints, severe symptoms of median nerve compression, and changes on neurophysiological tests. Surgery, synovectomy, and biopsy were performed. In the postoperative period, five patients (41%) developed chronic pain and reflex sympathetic dystrophy. Conclusion: A higher frequency of postoperative pain was observed in the patients, demonstrating the need for caution in the approach and treatment of this association.

A Modern Primer on Light Chain Amyloidosis in 592 Patients With Mass Spectrometry-Verified Typing.

OBJECTIVE: To describe the clinical and laboratory characteristics of patients with meticulously typed light chain (AL) amyloidosis. PATIENTS AND METHODS: Patients (N=592) with biopsy-proven, mass spectrometry-confirmed AL amyloidosis diagnosed from January 1, 2008, through August 31, 2015, were included. RESULTS: The median patient age at diagnosis was 63 years. Thirty-four percent of patients (n=204) had isolated organ involvement, mostly heart (19% [n=115]) followed by kidney (9% [n=53]). In contrast, 25% (n=146) had more than 2 involved organs. Patients with isolated cardiac involvement had similar cardiac dysfunction compared with those with nonisolated cardiac amyloidosis. In contrast, isolated renal involvement was associated with increased proteinuria and higher estimated glomerular filtration rate compared with nonisolated renal amyloidosis. Serum and urine immunofixation electrophoresis results were positive in 80% and 88% of patients, respectively, with 94% of patients having at least 1 positive immunofixation electrophoresis result (serum or urine). The serum free light chain ratio was abnormal in 91% of patients. When all monoclonal protein studies were combined, only 1 patient (0.2%) had normal results. The 1- and 5-year survival rates were 65% and 46%, respectively. Survival of patients with cardiac amyloidosis was not influenced by the number of involved organs (1 vs >1 organ), emphasizing the prognostic significance of cardiac involvement. CONCLUSION: When mass spectrometry is used to definitively type amyloid, only a fraction of a percent of patients with AL have negative monoclonal protein studies, unlike historical reports. Patient characteristics and outcomes of accurately typed patients are described.

In Vivo and In Vitro Monitoring of Amyloid Aggregation via BSA@FGQDs Multimodal Probe.

Early detection of peptide aggregate intermediates is quite challenging because of their variable and complex nature as well as due to lack of reliable sensors for diagnosis. Herein, we report the detection of monomers and oligomers using specified fluorescence and a magnetic resonance imaging (MRI) multimodal probe based on bovine-serum-albumin-capped fluorine functionalized graphene quantum dots (BSA@FGQDs). This probe enables in vitro fluorescence-based monitoring of human islet amyloid polypeptide (hIAPP), insulin, and amyloid ß(1-42) (Aß42) monomers and oligomers during the fibrillogenesis dynamic. Up to 90% fluorescence quenching of BSA@FGQDs probe upon addition of amyloid monomers/oligomers was observed due to static quenching and nonradiative energy transfer. Moreover, the BSA@FGQDs probe shows 10 times higher signals in detecting amyloid intermediates and fibrils than that of conventional thioflavin dye. A negative Δ G° value (-36.21 kJ/mol) indicates spontaneous interaction of probe with the peptide. These interactions are hydrogen bonding and hydrophobic as proved by thermodynamic parameters. Visual binding clues of BSA@FGQDs with different morphological states of amyloid protein was achieved through electron microscopy. Furthermore, intravenous and intracranial injection of BSA@FGQDs probe in Alzheimer model mice brain enabled in vivo detection of amyloid plaques in live mice brain by 19F MRI through contrast enhancement. Our proposed probe not only effectively monitors in vitro fibrillation kinetics of number of amyloid proteins with higher sensitivity and specificity than thioflavin dye, but also, the presence of a 19F center makes BSA@FGQDs an effective probe as a noninvasive and nonradiative in vivo detection probe for amyloid plaques.