Causes of AA amyloidosis: a systematic review

Understanding alpha-synuclein aggregation propensity in animals and humans

Alpha-synuclein (α-syn) aggregation plays a critical role in the pathogenicity of Parkinson's Disease (PD). This study aims to evaluate the aggregation propensity of α-syn fragment peptides designed using the variability found in humans and animals. Thioflavin T (ThT) and transmission electron microscopy (TEM) were used to validate the formation of fibrils to identify important amino acid residues. Human α-syn fragments 51-75, 37-61, 62-86, 76-100, and 116-140 demonstrate a significantly higher tendency to aggregate compared to fragments 1-25, 26-50, and 91-115. All species analyzed of the α-syn 37-61 and 62-86 regions were shown to form fibrils on both ThT and TEM. The α-syn 37-61 and 62-86 fragment regions exhibited a high susceptibility to aggregation, with fibril formation observed in all species. The A53T mutation in several α-syn 37-61 fragments may enhance their propensity for aggregation, suggesting a correlation between this mutation and the capacity for fibril formation. Furthermore, the presence of the non-amyloid-β component (NAC) region, specifically in α-syn 62-86, was consistently observed in several fragments that displayed fibril formation, indicating a potential correlation between the NAC region and the process of fibril formation in α-syn. Finally, the combination of a high quantity of valine and a low quantity of acidic amino acids in these fragments may serve as indicators of α-syn fibril formation.

2024 Update on Classification, Etiology, and Typing of Renal Amyloidosis: A Review

Amyloidosis is a protein folding disease that causes organ injuries and even death. In humans, 42 proteins are now known to cause amyloidosis. Some proteins become amyloidogenic as a result of a pathogenic variant as seen in hereditary amyloidoses. In acquired forms of amyloidosis, the proteins form amyloid in their wild-type state. Four types (serum amyloid A, transthyretin, apolipoprotein A-IV, and β2-macroglobulin) of amyloid can occur either as acquired or as a mutant. Iatrogenic amyloid from injected protein medications have also been reported and AIL1RAP (anakinra) has been recently found to involve the kidney. Finally, the mechanism of how leukocyte cell-derived chemotaxin 2 (ALECT2) forms amyloid remains unknown. This article reviews the amyloids that involve the kidney and how they are typed.

bDMARD can prevent the progression of AA amyloidosis to end-stage renal disease

INTRODUCTION

AA amyloidosis (AA) can be the consequence of any chronic inflammatory disease. AA is associated with chronic inflammatory diseases (cid+AA), autoinflammatory syndromes (auto+AA) or AA of unknown origin or idiopathic AA (idio+AA). The major organ manifestation is renal AA that can progress to end-stage renal disease (ESRD) and multiple organ failure.

MATERIALS AND METHODS

This study is a monocentric retrospective analysis of the renal outcome and survival of patients with cid+AA (n=34), auto+AA (n=24) and idio+AA (n=25) who were treated with cytokine-inhibiting biological disease-modifying antirheumatic drugs (bDMARDs).

RESULTS

83 patients with renal AA were identified and followed for a mean observational period of 4.82 years. C reactive protein (CRP), serum amyloid alpha and proteinuria were significantly reduced with bDMARD therapy. Progression to ESRD was prevented in 60% (cid+AA), 88% (auto+AA) and 81% (idio+AA) of patients. Tocilizumab was given to 34 patients with cid+AA and idio+AA and was more effective in reducing CRP and progression to ESRD and death compared with other bDMARDs.

CONCLUSIONS

bDMARDs reduce systemic inflammation in various diseases, leading to a reduction of proteinuria and prevention of ESRD. Importantly, tocilizumab was more effective than other bDMARDs in controlling systemic inflammation in patients with chronic inflammatory diseases and idiopathic AA, leading to better renal and overall survival.

Amyloidosis and Amyloidogenesis: One Name, Many Diseases

Amyloidosis is a heterogenous group of disorders, caused by the deposition of insoluble fibrils derived from misfolded proteins in the extracellular space of various organs. These proteins have an unstable structure that causes them to misfold, aggregate, and deposit as amyloid fibrils with the pathognomonic histologic property of green birefringence when viewed under cross-polarized light after staining with Congo red. Amyloid fibrils are insoluble and degradation-resistant; resistance to catabolism results in progressive tissue amyloid accumulation. The outcome of this process is organ disfunction independently from the type of deposited protein, however there can be organ that are specifically targeted from certain proteins.

A case of pulmonary transthyretin amyloidosis with concurrent mycobacterial tuberculosis infection

Amyloidosis is a pathological deposition disease that causes a spectrum of organ dysfunction. Pulmonary involvement is generally associated with immunoglobulin light chain type (AL) amyloid. Transthyretin (ATTR) amyloid build up in the lung is thought to be a senile disease observed usually as a finding at autopsy. We describe a case of pulmonary ATTR amyloidosis with concurrent mycobacterial tuberculosis infection.

Deactivation of the Unfolded Protein Response Aggravated Renal AA Amyloidosis in HSF1 Deficiency Mice

Systemic amyloid A (AA) amyloidosis, which is considered the second most common form of systemic amyloidosis usually takes place several years prior to the occurrence of chronic inflammation, generally involving the kidney. Activated HSF1, which alleviated unfolded protein response (UPR) or enhanced HSR, is the potential therapeutic target of many diseases. However, the effect of HSF1 on AA amyloidosis remains unclear. This study focused on evaluating effect of HSF1 on AA amyloidosis based on HSF1 knockout mice. As a result, aggravated amyloid deposits and renal dysfunction have been found in HSF1 knockout mice. In progressive AA amyloidosis, HSF1 deficiency enhances serum amyloid A production might to lead to severe AA amyloid deposition in mice, which may be related to deactivated unfolded protein response as well as enhanced inflammation. Thus, HSF1 plays a significant role on UPR related pathway impacting AA amyloid deposition, which can mitigate amyloidogenic proteins from aggregation pathologically and is the possible way for intervening with the pathology of systemic amyloid disorder. In conclusion, HSF1 could not only serve as a new target for AA amyloidosis treatment in the future, but HSF1 knockout mice also can be considered as a valuable novel animal model for renal AA amyloidosis.

Accelerating protein aggregation and amyloid fibrillation for rapid inhibitor screening

The accumulation and deposition of amyloid fibrils, also known as amyloidosis, in tissues and organs of patients has been found to be linked to numerous devastating neurodegenerative diseases. The aggregation of proteins to form amyloid fibrils, however, is a slow pathogenic process, and is a major issue for the evaluation of the effectiveness of inhibitors in new drug discovery and screening. Here, we used microdroplet reaction technology to accelerate the amyloid fibrillation process, monitored the process to shed light on the fundamental mechanism of amyloid self-assembly, and demonstrated the value of the technology in the rapid screening of potential inhibitor drugs. Proteins in microdroplets accelerated to form fibrils in milliseconds, enabling an entire cycle of inhibitor screening for Aβ40 within 3 minutes. The technology would be of broad interest to drug discovery and therapeutic design to develop treatments for diseases associated with protein aggregation and fibrillation.

Characteristics and course of patients with AA amyloidosis: single centre experience with 174 patients from Turkey

OBJECTIVES

This study aimed to evaluate the clinical, laboratory and genetic characteristics and outcomes of patients with AA amyloidosis.

METHODS

Patients followed up in a tertiary referral centre in Turkey with the diagnosis of inflammatory rheumatic diseases and immunohistologically proven AA amyloidosis were included in the study and retrospectively analysed.

RESULTS

Among 184 patients with the diagnosis of AA amyloidosis, 174 (83 female, 91 male) were included in the analysis. The most common cause of AA amyloidosis was FMF (78.7%), and 91% of FMF-AA amyloidosis patients were carrying the p.M694V variant (74.1% homozygous). AA amyloidosis was identified earlier in patients with homozygous or compound heterozygous MEFV exon 10 variants compared with the heterozygous patients (27, 30 and 41 years, respectively). Patients with an estimated glomerular filtration rate <60 ml/min at admission had a higher frequency of progression to end-stage renal disease (P < 0.001). The overall mortality rate was 15.3% and it increased gradually in association with the amyloid burden (10% in patients with renal, 15% in renal + gastrointestinal and 43% in those with additional cardiac involvement). Renal findings responded completely to treatment in 31% of the patients, a partial response was observed in 4%, a stable course in 23.6% and progression in 38.5%. Amyloid storm was identified in nine patients and was found to be associated with increased mortality within 1 year.

CONCLUSION

FMF patients still constitute the majority of AA amyloidosis patients in Turkey. The MEFV genotype and associated inflammatory load may affect the age of onset of AA amyloidosis, and earlier diagnosis and stricter follow-up and treatment may delay progression of the disease.

AA amyloidosis With Ig-Dominant Staining and Diagnostically Unusual Features

Introduction

Although serum amyloid A (AA) amyloid may occasionally show nonspecific staining by immunofluorescence (IF), the correct diagnosis can usually be determined by integrating pathologic features and clinical scenario, and using AA amyloid immunohistochemistry (IHC) and/or mass spectrometry. A recent mass spectrometry-based study described false-positive Ig IF staining in a subset of AA amyloid cases.

Methods

We sought to delineate clinicopathologic features of AA amyloid with Ig-dominant staining by using a retrospective review.

Results

AA amyloid with Ig-dominant staining was identified in 10 patients from 5 institutions, representing 1.2% to 4% of AA amyloid kidney biopsies. Evidence of a monoclonal protein was documented in 0% to 2.7% of patients with AA amyloid screened for inclusion, but 30% of those with Ig-dominant staining. The patient population had equal sex distribution and presented at median age of 68.5 years with nephrotic proteinuria and kidney impairment. Etiologies of AA amyloid included injection drug use (30%), autoimmune disease (20%), and chronic infection (10%); 40% had no identified clinical association. On biopsy, heavy chain (co)dominant staining by IF (in 80%), discordant distribution in Ig staining (in 20%), tubulointerstitial nephritis (in 30%), and/or crescents (in 10%) were present. Two of 3 patients with paraproteinemia had concordant heavy and/or light chain dominant staining within the AA amyloid. Two cases were initially misdiagnosed as Ig-associated amyloidosis.

Conclusion

We describe the morphologic spectrum of AA amyloidosis with Ig-dominant staining which may have clinical, laboratory, and pathologic overlap with amyloid light chain (AL), amyloid heavy chain, and heavy and light chain (AHL) amyloidosis.

A rare case of hydatid cyst-associated AA amyloidosis and literature review of hydatid cyst-associated nephropathy

Hydatid disease is an infective picture caused by echinococcus, which progresses with cysts in various organs, especially in the liver. Renal involvement is an unusual location in the course of the disease. Although mostly asymptomatic renal cysts are seen, rarely glomerular or tubular associated nephropathy develops. In addition, the development of amyloidosis has been shown previously in patients with untreated chronic hydatid cysts. We wanted to bring a 27-year-old female patient with a 10-year history of hydatid cyst and AA amyloidosis to the literature. In addition, in our literature review for hydatid disease-associated nephropathies, we brought together data from 12 studies involving a total of 21 cases. Of these cases, 3 were membranous glomerulonephritis (MGN), 5 were, membranoproliferative glomerulonephritis (MPGN), 1 was minimally change disease (MCD), 5 were AA amyloidosis (including our case), 3 were immunoglobulin A nephropathy (IgAN), 1 was tubulointerstitial nephritis (TIN), 1 was chronic kidney disease (CKD), 1 was TIN with mesangioproliferative glomerulonephritis (MesPGN), 1 was TIN with IgAN, 1 was MPGN with immunoglobulin M nephropathy (IgMN). In this way, we wanted to shed light on the relationship between Echinococcus and nephropathy. In this way, we wanted to emphasise the necessity of doing renal examinations in the follow-up of hydatid cyst patients.

Human lysozyme inhibits the fibrillation of serum amyloid a protein from systemic AA amyloidosis

BACKGROUND

Systemic AA amyloidosis is a world-wide occurring protein misfolding disease in humans and animals that arises from the formation of amyloid fibrils from serum amyloid A (SAA) protein and their deposition in multiple organs.

OBJECTIVE

To identify new agents that prevent fibril formation from SAA protein and to determine their mode of action.

MATERIALS AND METHODS

We used a cell model for the formation of amyloid deposits from SAA protein to screen a library of peptides and small proteins, which were purified from human hemofiltrate. To clarify the inhibitory mechanism the obtained inhibitors were characterised in cell-free fibril formation assays and other biochemical methods.

RESULTS

We identified lysozyme as an inhibitor of SAA fibril formation. Lysozyme antagonised fibril formation both in the cell model as well as in cell-free fibril formation assays. The protein binds SAA with a dissociation constant of 16.5 ± 0.6 µM, while the binding site on SAA is formed by segments of positively charged amino acids.

CONCLUSION

Our data imply that lysozyme acts in a chaperone-like fashion and prevents the aggregation of SAA protein through direct, physical interactions.

Localized Amyloid A amyloidsis of ureter: A case report

Amyloidosis of the ureter is a rare disease, distinguishing it from a neoplasm is difficult. A 64-year-old Japanese woman suffered from macrohematuria and left side hydronephrosis with ultrasound in 2014. Retrograde pyelography revealed no ureter tumor at that time. The patient had macrohematuria, left side hydronephrosis, and ureteral stenosis in the left ureter on retrograde pyelography. She was suspected of having a ureter tumor when she was 71 years old in 2021. The patient underwent ureteroscopy with biopsy. Pathological specimens contained the amyloid A component, based on immunohistochemistry staining. We diagnosed the patient with amyloid A amyloidosis of the ureter.

Therapeutic effects of biological treatments on AA amyloidosis associated with inflammatory bowel disease: a case report and literature review

AA amyloidosis is a rare and significant complication of long-term inflammation that can be caused by a variety of disorders, including inflammatory bowel disease, and is linked to an increased risk of morbidity and mortality. To date, there has been no effective direct treatment, and treatment aims at treating the underlying condition with potent immunosuppression to limit inflammatory activity and, as a result, switch off amyloidogenesis. Theoretically, biological treatment can control AA amyloidosis by inducing and maintaining inflammatory bowel disease remission and inhibiting the synthesis of Serum Amyloid A, which is an acute phase reactant and precursor protein of AA amyloidosis that accumulates in the organs. We report the first case of ustekinumab's therapeutic effect after infliximab's loss of response in AA amyloidosis associated with Crohn's disease. We also conducted a literature review of the therapeutic effect of biological treatment on AA amyloidosis.

Intestinal Reactive Amyloid A (AA) Amyloidosis in a Patient With Multiple Myeloma: A Case Report and Literature Review

Amyloidosis is a rare group of disorders characterized by the extracellular deposition of misfolded protein aggregates that interfere with the function of the tissue affected. In some patients, the presenting symptom of monoclonal gammopathies, such as multiple myeloma, can be a gastrointestinal bleed with a further report of amyloidosis in gastrointestinal samples. In all the cases the pathology report is read as AL (light chain) amyloidosis. We present a case of a 57-year-old male patient with no medical history who debuted with gastrointestinal bleeding. A colonoscopy revealed a colonic ulcer with a pathologic diagnosis of amyloid A (AA) amyloidosis. Further investigation led to the finding of multiple myeloma (MM) with no evidence of systemic amyloidosis. Although there is little evidence in the literature of the association or even causative relationship between multiple myeloma and AA amyloidosis, our case highlights the importance of searching for an underlying monoclonal gammopathy like MM in a patient with a confirmed diagnosis of AA amyloidosis.

Secondary amyloidosis with concomitant gastric GIST and gastric adenocarcinoma - A case report

Secondary amyloidosis is a well-established entity and has been described in association with chronic inflammatory conditions such as rheumatoid arthritis, ankylosing spondylitis, bronchiectasis, tuberculosis, etc., It has also been reported in association with neoplasms such as Hodgkin's lymphoma, Waldenstrom's macroglobulinemia, renal cell carcinoma, lung carcinoma, etc. However, only a few case reports documenting the association of amyloidosis with gastrointestinal tumor (GIST) and gastric adenocarcinoma are available in the literature. Hereby, we report a case of a 74-year-old male who presented with colicky abdominal pain and vomiting. Ultrasonography revealed a common bile duct (CBD) stone and a small extra-luminal gastric mass. Endoscopic retrograde cholangiopancreatography (ERCP) was performed to remove the CBD stone which revealed an incidental finding of gastric ulcer. A biopsy was taken from the gastric ulcer which on histopathological examination was confirmed as adenocarcinoma leading onto total gastrectomy. During total gastrectomy, an inadvertent injury to the spleen led to simultaneous splenectomy. Multiple samples from the gastric ulcer, the extra-luminal gastric mass, and the spleen were subjected to histopathological examination. Gastric ulcer was confirmed as adenocarcinoma, gastric extra-luminal mass was confirmed as GIST, and splenic examination revealed widespread deposition of amyloid which on Congo-red stain imparted an apple-green birefringence on polarizing microscopy. To the best of our knowledge, this is the first-ever case of such an association where gastric adenocarcinoma occurred with concomitant gastric GIST and secondary amyloidosis of the spleen.

Cardiac Amyloidosis in the Setting of a Sarcomatous Pericardial Mass

Cardiac amyloidosis is a significantly underdiagnosed disease but should be suspected in anyone with restrictive heart physiology. Here, we present a case of a sarcomatous pericardial mass confounding the patient's progressive diastolic heart failure. Amyloidosis was eventually discovered by piecing together serial transthoracic echocardiogram, functional MRI, and technetium-99m (99mTc) pyrophosphate scintigraphy findings along with a negative lab workup. The presence of the sarcomatous pericardial mass raised the question of whether it played a role in the onset and progression of amyloidosis, but nonetheless, the presence of both diseases rendered multifaceted challenges regarding our patient's care. Anyone suspected to have amyloidosis should receive appropriate testing for a definitive diagnosis to catch the disease process and offer early treatment, as exciting research is emerging showing transthyretin stabilizers to have a reduction in all-cause mortality.

Simulations of Amyloid-Forming Peptides in the Crystal State

There still is little treatment available for amyloid diseases, despite their significant impact on individuals and the social and economic implications for society. One reason for this is that the physical nature of amyloid formation is not understood sufficiently well. Therefore, fundamental research at the molecular level remains necessary to support the development of therapeutics. A few structures of short peptides from amyloid-forming proteins have been determined. These can in principle be used as scaffolds for designing aggregation inhibitors. Attempts to this end have often used the tools of computational chemistry, in particular molecular simulation. However, few simulation studies of these peptides in the crystal state have been presented so far. Hence, to validate the capability of common force fields (AMBER19SB, CHARMM36m, and OPLS-AA/M) to yield insight into the dynamics and structural stability of amyloid peptide aggregates, we have performed molecular dynamics simulations of twelve different peptide crystals at two different temperatures. From the simulations, we evaluate the hydrogen bonding patterns, the isotropic B-factors, the change in energy, the Ramachandran plots, and the unit cell parameters and compare the results with the crystal structures. Most crystals are stable in the simulations but for all force fields there is at least one that deviates from the experimental crystal, suggesting more work is needed on these models.

Proteomic Identification and Clinicopathologic Characterization of Splenic Amyloidosis

The spleen is a commonly encountered specimen in surgical pathology. However, little is known about the incidence, morphologic pattern, and clinical features of spleens involved by amyloidosis. We retrospectively identified 69 spleen amyloid cases typed using a proteomics-based method between 2008 and 2020. The frequency of amyloid types, clinicopathologic features, and distribution of amyloid deposits were assessed. Four amyloid types were detected: immunoglobulin light chain (AL) (N=30; 43.5%); leukocyte chemotactic factor 2 amyloidosis (ALECT2) (N=30; 43.5%); amyloid A (AA) (N=8; 11.6%); and fibrinogen alpha (AFib) (N=1; 1.4%). The splenic amyloid showed 5 distinct distribution patterns: (1) diffuse pattern, exhibited by most AL cases; (2) red pulp pattern, exhibited by most ALECT2 cases; (3) multinodular pattern, seen in subsets of AA and AL-kappa cases; (4) mass-forming pattern, seen in the AFib case; and (5) vascular only, seen in a subset of AA cases. Atraumatic splenic rupture was the most common reason for splenectomy in AL cases, while most ALECT2 spleens were removed incidentally during an unrelated abdominal surgery. Splenomegaly was significantly more common in AA spleens than in AL or ALECT2 spleens and was often the reason for splenectomy in this group. In conclusion, splenic amyloid may be underrecognized as it is often an incidental finding. Although, as expected, many of the spleens were involved by AL amyloidosis, ALECT2 emerged as another common spleen amyloid type. Although the spleen amyloid types exhibited characteristic distribution patterns, proteomics-based typing is warranted as some morphologic overlap still exists. Awareness of ALECT2 as a major spleen amyloid type is important for appropriate diagnostic workup and patient management.

Current approaches to the diagnosis and management of amyloidosis

Amyloidosis is a collection of diseases caused by the misfolding of proteins that aggregate into insoluble amyloid fibrils and deposit in tissues. While these fibrils may aggregate to form insignificant localised deposits, they can also accumulate in multiple organs to the extent that amyloidosis can be an immediately life-threatening disease, requiring urgent treatment. Recent advances in diagnostic techniques and therapies are dramatically changing the disease landscape and patient prognosis. Delays in diagnosis and treatment remain the greatest challenge, necessitating physician awareness of the common clinical presentations that suggest amyloidosis. The most common types are transthyretin (ATTR) amyloidosis followed by immunoglobulin light-chain (AL) amyloidosis. While systemic AL amyloidosis was previously considered a death sentence with no effective therapies, significant improvement in patient survival has occurred over the past 2 decades, driven by greater understanding of the disease process, risk-adapted adoption of myeloma therapies such as proteosome inhibitors (bortezomib) and monoclonal antibodies (daratumumab) and improved supportive care. ATTR amyloidosis is an underdiagnosed cause of heart failure. Technetium scintigraphy has made noninvasive diagnosis much easier, and ATTR is now recognised as the most common type of amyloidosis because of the increased identification of age-related ATTR. There are emerging ATTR treatments that slow disease progression, decrease patient hospitalisations and improve patient quality of life and survival. This review aims to update physicians on recent developments in amyloidosis diagnosis and management and to provide a diagnostic and treatment framework to improve the management of patients with all forms of amyloidosis.

Current Understanding of Systemic Amyloidosis and Underlying Disease Mechanisms

Amyloidosis is a group of diverse disorders caused by misfolded proteins that aggregate into insoluble fibrils and ultimately cause organ damage. In medical practice, amyloidosis classification is based on the amyloid precursor protein type, of which amyloid immunoglobulin light chain, amyloid transthyretin, amyloid leukocyte chemotactic factor 2, and amyloid derived from serum amyloid A protein are the most common. Distinct mechanisms appear to be predominantly operational in the pathogenesis of particular types of amyloidosis, including increased protein precursor synthesis, somatic or germ line mutations, and inherent instability in the precursor protein in its wild form. An increased supply of misfolded proteins and/or a decreased capacity of the protein quality control systems can result in an imbalance that leads to increased circulation of misfolded proteins. Although the detection of mature fibrils is the basis for diagnosis of amyloidosis, a growing body of evidence has implicated the prefibrillar species as proteotoxic and key contributors to the development of the disease.

The relation between C-reactive protein and serum amyloid A in patients with autoinflammatory diseases

BACKGROUND

Autoinflammatory diseases are rare disorders of the innate immune system characterized by fever and other signs of inflammation. A feared complication of autoinflammatory diseases is the development of AA amyloidosis. AA amyloidosis is caused by extracellular deposition of soluble serum amyloid A (SAA) proteins as insoluble amyloid fibrils leading to organ damage. Prolonged high levels of SAA are a prerequisite to develop AA amyloidosis. Since measurement of SAA is relatively expensive and sometimes unavailable, C-reactive protein (CRP) is often used as a surrogacy marker to test for inflammation.

OBJECTIVE

The aim of this research is to evaluate the possible relation between CRP and SAA.

METHODS

A retrospective cohort of patients with autoinflammatory diseases (n = 99) where SAA and CRP blood testing was performed in the period between 2015 and 2021 in the University Medical Centre in Groningen was used to investigate the correlation between CRP and SAA.

RESULTS

CRP and SAA have a high correlation (rho = 0.755, p < 0.001). A CRP value below 0.45 mg/L results in 100% sensitivity for SAA below 4 mg/L. CRP below 5 mg/L is a good predictor of SAA below 4 mg/L with 85.4% sensitivity and 83.6% specificity. Only prednisone and erythrocyte sedimentation rate (ESR) significantly influence the relation between CRP and log₁₀SAA.

CONCLUSION

There was a significant correlation between CRP and SAA in our retrospective cohort. CRP levels below 5 mg/L proved to be highly predictive of SAA levels below 4 mg/L. This may not be true for patients on steroids.

A comprehensive mini-review on amyloidogenesis of different SARS-CoV-2 proteins and its effect on amyloid formation in various host proteins

Amyloidogenesis is the inherent ability of proteins to change their conformation from native state to cross β-sheet rich fibrillar structures called amyloids which result in a wide range of diseases like Parkinson's disease, Alzheimer's disease, Finnish familial amyloidosis, ATTR amyloidosis, British and Danish dementia, etc. COVID-19, on the other hand is seen to have many similarities in symptoms with other amyloidogenic diseases and the overlap of these morbidities and symptoms led to the proposition whether SARS-CoV-2 proteins are undergoing amyloidogenesis and whether it is resulting in or aggravating amyloidogenesis of any human host protein. Thus the SARS-CoV-2 proteins in infected cells, i.e., Spike (S) protein, Nucleocapsid (N) protein, and Envelope (E) protein were tested via different machinery and amyloidogenesis in them were proven. In this review, we will analyze the pathway of amyloid formation in S-protein, N-protein, E-protein along with the effect that SARS-CoV-2 is creating on various host proteins leading to the unexpected onset of many morbidities like COVID-induced Acute Respiratory Distress Syndrome (ARDS), Parkinsonism in young COVID patients, formation of fibrin microthrombi in heart, etc., and their future implications.

Revisiting misfolding propensity of serum amyloid A1: Special focus on the signal peptide region

AA amyloidosis is the result of overproduction and aberrant processing of acute-phase serum amyloid A1 (SAA1) by hepatocytes. Proteolytic cleavage of SAA1 is believed to play a central role in AA amyloid formation. The SAA1 protein undergoes a cleavage of 18 residues consisting of the signal peptide at the N-terminal region. To better understand the mechanism behind systemic amyloidosis in the SAA1 protein, we studied the misfolding propensity of the signal peptide region. We first examined the signal peptide amino acid SAA derived from different animal species. A library of 16 peptides was designed to evaluate the propensity of aggregation. The amyloidogenic potential of each SAA1 signal peptide homolog was assessed using in silico Tango program, thioflavin T (ThT) fluorescence, transmission electron microscopy (TEM), and seeding with misfolded human SAA1 signal peptide. After 7 days of incubation, most of the SAA1 signal peptide fragments had the propensity to form fibrils at a concentration of 100 μM in 50 mM Tris buffer at 37 °C by TEM. All peptides were able to generate fibrils at a higher concentration, i.e 500 μM in 25 mM Tris buffer with 50% HFIP, by ThT. All SAA1 signal synthetic peptides designed from the different animal species had the propensity to misfold and form fibrils, particularly in species with low occurrence of systemic amyloidosis. The human SAA1 signal peptide region was capable to seed the SAA1 1–25 and 32–47 peptide regions. Characterizing fibrillar conformations are relevant for seeding intact and/or fragmented SAA, which may contribute, to the mechanism of protein misfolding. This research signifies the importance of the signal peptide region and its possible contribution to the misfolding of aggregation-prone proteins.

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Serum amyloid A1 (SAA1) signal peptide synthetic fragments have the propensity to form fibrils.

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SAA1 signal peptide, 1–25, and 51–75 regions are prone-to-aggregate.

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Human SAA1 signal peptide is capable to seeds human SAA1 1–25 and 32–47 fragments.

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SAA1 signal peptide fibrils may have a role in seeding intact and/or fragmented SAA1.

Serum Amyloid A Protein–Associated Kidney Disease: Presentation, Diagnosis, and Management

Serum amyloid A protein (AA) amyloidosis, also known as secondary amyloidosis, is a known consequence of chronic inflammation and results from several conditions including inflammatory arthritis, periodic fever syndromes, and chronic infection. AA amyloidosis can lead to multiorgan dysfunction, including changes in glomerular filtration rate and proteinuria. Definitive diagnosis requires tissue biopsy, and management of AA amyloid kidney disease is primarily focused on treating the underlying inflammatory condition to stabilize glomerular filtration rate, reduce proteinuria, and slow potential progression to kidney failure. In this narrative review, we describe the causes, pathophysiology, presentation, and pathologic diagnosis of AA amyloid kidney disease using an illustrative case of biopsy-proven AA amyloid kidney disease in a patient with long-standing rheumatoid arthritis who had a favorable response to interleukin 6 inhibition. We conclude the review with a description of established and more novel therapies for AA amyloidosis including published cases of use of tocilizumab (an interleukin 6 inhibitor) in biopsy-proven AA amyloid kidney disease.

Re-Definition of the Epidemiology of Cardiac Amyloidosis

The epidemiology of cardiac amyloidosis (CA), traditionally considered a rare and incurable disease, has changed drastically over the last ten years, particularly due to the advances in diagnostic methods and therapeutic options in the field of transthyretin CA (ATTR-CA). On the one hand, the possibility of employing cardiac scintigraphy with bone tracers to diagnose ATTR-CA without a biopsy has unveiled the real prevalence of the disease; on the other, the emergence of effective treatments, such as tafamidis, has rendered an early and accurate diagnosis critical. Interestingly, the following subgroups of patients have been found to have a higher prevalence of CA: elderly subjects > 75 years, patients with cardiac hypertrophy hospitalized for heart failure with preserved ejection fraction, subjects operated on for bilateral carpal tunnel syndrome, patients with cardiac hypertrophy not explained by concomitant factors and individuals with aortic valve stenosis. Many studies investigating the prevalence of CA in these particular populations have contributed to rewriting the epidemiology of the disease, increasing the awareness of the medical community for a previously underappreciated condition. In this review, we summarized the latest evidence on the epidemiology of CA according to the different clinical settings typically associated with the disease.

Local Insulin-Derived Amyloidosis Model Confronted with Silymarin: Histological Insights and Gene Expression of MMP, TNF-α, and IL-6

Amyloidosis is a heterogeneous group of protein deposition diseases associated with the presence of amyloid fibrils in tissues. Analogs of insulin that are used for treating diabetic patients (including regular insulin) can form amyloid fibrils, both in vitro and in vivo as reported in patients. The main purpose of this study was the induction of localized insulin-generated amyloidosis and the observation of silymarin effects on this process. In order to obtain amyloid structures, regular insulin was incubated at 37 °C for 24 h. Congo red absorbance and transmission electron microscopy images validated the formation of amyloid fibrils. Those fibrils were then injected subcutaneously into rats once per day for 6, 12 or 18 consecutive days in the presence or absence of silymarin, and caused development of firm waxy masses. These masses were excised and stained with Hematoxylin and Eosin, Congo red and Thioflavin S. Histological examination showed adipose cells and connective tissue in which amyloid deposition was visible. Amyloids decreased in the presence of silymarin, and the same effect was observed when silymarin was added to normal insulin and injected subsequently. Furthermore, plasma concentrations of MMP2, TNF-α, and IL-6 inflammatory factors were measured, and their gene expression was locally assessed in the masses by immunohistochemistry. All three factors increased in the amyloidosis state, while silymarin had an attenuating effect on their plasma levels and gene expression. In conclusion, we believe that silymarin could be effective in counteracting insulin-generated local amyloidosis.

Stress-responsive regulation of extracellular proteostasis

Genetic, environmental, and aging-related insults can promote the misfolding and subsequent aggregation of secreted proteins implicated in the pathogenesis of numerous diseases. This has led to considerable interest in understanding the molecular mechanisms responsible for regulating proteostasis in extracellular environments such as the blood and cerebrospinal fluid (CSF). Extracellular proteostasis is largely dictated by biological pathways comprising chaperones, folding enzymes, and degradation factors localized to the ER and extracellular space. These pathways limit the accumulation of nonnative, potentially aggregation-prone proteins in extracellular environments. Many reviews discuss the molecular mechanisms by which these pathways impact the conformational integrity of the secreted proteome. Here, we instead focus on describing the stress-responsive mechanisms responsible for adapting ER and extracellular proteostasis pathways to protect the secreted proteome from pathologic insults that challenge these environments. Further, we highlight new strategies to identify stress-responsive pathways involved in regulating extracellular proteostasis and describe the pathologic and therapeutic implications for these pathways in human disease.

Protein Aggregation and Self Assembly in Health and Disease

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Self-attachment of proteins leading to the formation of highly insoluble protein oligomers and aggregates has become an important focus of research owing to its diverse implications in pathophysiology and diseases. This has become a more frequent phenomenon in most neurological and neurodegenerative diseases as well as in dementia. In recent years such event of protein aggregation has linked to other disease conditions, disorders or adverse health conditions. Interestingly, aggregation of protein also plays role in development, growth or metabolism. Most often physiological proteins are initially bio-synthesised in native or nascent geometrical forms or conformations but later they undergo specific folding pattern and thereby acquire a stable configuration that is biologically relevant and active. It is highly important that these proteins remain in their biologically active configuration in order to exert their functional properties. Any alteration or change to this structural configuration can be detrimental to their specific functions and may cause pathological consequences leading to the onset of diseases or disorders. Several factors such as the action of chaperones, binding partners, physiological metal ions, pH level, temperature, ionic strength, interfacial exposure (solid-liquid, liquid-liquid, gas-liquid), mutation and post translational modification, chemical changes, interaction with small molecules such as lipids, hormones, etc. and solvent environment have been either identified or proposed as important factors in conferring the ultimate status of protein structure and configuration. Among many misfolding protein conformations, self-assembly or aggregation is the most significant. It leads to the formation of highly oligomeric self-aggregates that precipitate and interfere with many biochemical processes with serious pathological consequences. The most common implication of protein aggregation leading to the formation of deposits / plaques of various morphological types is the onset of neurological and neurodegenerative diseases that include Alzheimer’s, Parkinson’s, Huntington, ALS (Amyotrophic Lateral Sclerosis), CJD (Creutzfeldt Jakob Dementia), Prion diseases, Amyloidosis and other forms of dementia. However increasingly studies revealed that protein aggregation may also be associated with other diseases such as cancer, type 2 diabetes, renal, corneal and cardiovascular diseases. Protein aggregation diseases are now considered as part of “Proteinopathy” which refers to conditions where proteins become structurally abnormal or fail to fold into stable normal configurations. In this review, we reflect on various aspects of protein self-aggregation, potential underlying causes, mechanism, role of secondary structures, pathological consequences and possible intervention strategies as reported in published literatures.

Vitreous involvement as initial presentation of hereditary transthyretin amyloidosis related to the rare TTR Ile107Met (p.Ile127Met) pathogenic variant

BACKGROUND

Hereditary transthyretin amyloidosis (ATTR) is a multisystemic disease with autosomal dominant inheritance, characterized by the deposition of amyloid-insoluble proteins. We describe a case of vitreous amyloidosis as the initial presentation of ATTRv amyloidosis resulting from the rare Ile107Met (p.Ile127Met) pathogenic variant.

MATERIALS AND METHODS

Ophthalmic examination, multimodal imaging, vitreous biopsy, and genetic testing were performed to confirm the diagnosis.

RESULTS

A 44-year-old woman presented with blurred vision and floaters in both eyes (OU) for 1 year. The vitreous showed numerous strand-like opacities that were predominant in the anterior vitreous of OU. After a systemic workup and excluding malignancy, vitreous amyloidosis was suspected. Pars plana vitrectomy (PPV) of the left eye (OS) was performed, and a vitreous sample was obtained for histopathology. Homogeneous eosinophilic granular and filamentous deposits that showed an orange-red color with Congo red special stain were observed in the vitreous material, confirming vitreous amyloidosis. A PPV for the right eye (OD) was performed, and her vision at discharge was 20/20 OU. Systemic evaluation discarded neurologic or other systemic manifestations; however, there was familiar involvement in three generations with neurologic symptomatology, confirming an autosomal dominant inheritance pattern. Molecular analysis of the TTR gene showed a likely pathogenic variant Ile107Met (p.Ile127Met).

CONCLUSIONS

The present report describes a patient with ATTRv amyloidosis with initial vitreous involvement and the pathogenic variant Ile107Met (p.Ile127Met). It is important to consider vitreous amyloidosis as part of the non-malignant, non-infectious uveitis masquerade syndromes.

SAA fibrils involved in AA amyloidosis are similar in bulk and by single particle reconstitution: A MAS solid-state NMR study

AA amyloidosis is one of the most prevalent forms of systemic amyloidosis and affects both humans and other vertebrates. In this study, we compare MAS solid-state NMR data with a recent cryo-EM study of fibrils involving full-length murine SAA1.1. We address the question whether the specific requirements for the reconstitution of an amyloid fibril structure by cryo-EM can potentially yield a bias towards a particular fibril polymorph. We employ fibril seeds extracted from in to vivo material to imprint the fibril structure onto the biochemically produced protein. Sequential assignments yield the secondary structure elements in the fibril state. Long-range DARR and PAR experiments confirm largely the topology observed in the ex-vivo cryo-EM study. We find that the β-sheets identified in the NMR experiments are similar to the β-sheets found in the cryo-EM study, with the exception of amino acids 33–42. These residues cannot be assigned by solid-state NMR, while they adopt a stable β-sheet in the cryo-EM structure. We suggest that the differences between MAS solid-state NMR and cryo-EM data are a consequence of a second conformer involving residues 33–42. Moreover, we were able to characterize the dynamic C-terminal tail of SAA in the fibril state. The C-terminus is flexible, remains detached from the fibrils, and does not affect the SAA fibril structure as confirmed further by molecular dynamics simulations. As the C-terminus can potentially interact with other cellular components, binding to cellular targets can affect its accessibility for protease digestion.

AA amyloidosis complicating monoclonal gammopathies, an unusual feature validating the concept of "monoclonal gammopathy of inflammatory significance"?

INTRODUCTION

AL amyloidosis is caused by the proliferation of an immunoglobulin-secreting B cell clone. AA amyloidosis is a rare complication of chronic inflammation. However, some patients present with diseases combining monoclonal immunoglobulin production and chronic inflammation. The aim of this work was to describe cases of AA amyloidosis associated with monoclonal gammopathies.

PATIENTS AND METHODS

We reviewed all patients reported in French national amyloid centres presenting with AA amyloidosis and monoclonal gammopathy and performed a literature review. The quality of AA amyloidosis diagnosis and the causal relationship with monoclonal gammopathy were assessed.

RESULTS

In total, four patients from our centres and eight from the literature fulfilled the inclusion criteria. The haematological disorders presenting with monoclonal gammopathy were as follows: Waldenström macroglobulinaemia (n = 8), Schnitzler syndrome (n = 2), multiple myeloma (n = 1) and monoclonal gammopathy of undetermined significance (n = 1). Treatment strategies varied among the cases, with the treatment of the haematological disorder in 4 and anti-inflammatory treatment in 2.

CONCLUSION

Monoclonal gammopathies might be a rare and poorly known cause of AA amyloidosis. Such monoclonal gammopathies could be named "monoclonal gammopathies of inflammatory significance."

Serum Amyloid A Is Present in Human Saccular Intracranial Aneurysm Walls and Associates With Aneurysm Rupture

Saccular intracranial aneurysm (sIA) rupture leads to a disabling subarachnoid hemorrhage. Chronic inflammation and lipid accumulation in the sIA wall contribute to wall degenerative remodeling that precedes its rupture. A better understanding of the pathobiological process is essential for improved future treatment of patients carrying sIAs. Serum amyloid A (SAA) is an acute-phase protein produced in response to acute and chronic inflammation and tissue damage. Here, we studied the presence and the potential role of SAA in 36 intraoperatively resected sIAs (16 unruptured and 20 ruptured), that had previously been studied by histology and immunohistochemistry. SAA was present in all sIAs, but the extent of immunopositivity varied greatly. SAA immunopositivity correlated with wall degeneration (p = 0.028) and rupture (p = 0.004), with numbers of CD163-positive and CD68-positive macrophages and CD3-positive T lymphocytes (all p < 0.001), and with the expression of myeloperoxidase, matrix metalloproteinase-9, prostaglandin E-2 receptor, and cyclo-oxygenase 2 in the sIA wall. Moreover, SAA positivity correlated with the accumulation of apolipoproteins A-1 and B-100. In conclusion, SAA occurs in the sIA wall and, as an inflammation-related factor, may contribute to the development of a rupture-prone sIA.

Common Factors of Alzheimer's Disease and Rheumatoid Arthritis-Pathomechanism and Treatment

The accumulation of amyloid plaques, or misfolded fragments of proteins, leads to the development of a condition known as amyloidosis, which is clinically recognized as a systemic disease. Amyloidosis plays a special role in the pathogenesis of neurodegenerative diseases such as Alzheimer's disease (AD), Parkinson's disease, and rheumatoid arthritis (RA). The occurrence of amyloidosis correlates with the aging process of the organism, and since nowadays, old age is determined by the comfort of functioning and the elimination of unpleasant disease symptoms in the elderly, exposure to this subject is justified. In Alzheimer's disease, amyloid plaques negatively affect glutaminergic and cholinergic transmission and loss of sympathetic protein, while in RA, amyloids stimulated by the activity of the immune system affect the degradation of the osteoarticular bond. The following monograph draws attention to the over-reactivity of the immune system in AD and RA, describes the functionality of the blood-brain barrier as an intermediary medium between RA and AD, and indicates the direction of research to date, focusing on determining the relationship and the cause-effect link between these disorders. The paper presents possible directions for the treatment of amyloidosis, with particular emphasis on innovative therapies.

Trends in amyloidosis in spondyloarthritis: results from the Spanish National Inpatient Registry over a 17-year period (1999-2015)-TREND-EspA study

Objective

To assess the incidence of amyloidosis and trends therein in patients with spondyloarthritis (SpA) over a long period (17 years).

Methods

An observational retrospective population-based matched cohort study was conducted. All the admissions of patients with SpA, including ankylosing spondylitis (AS), psoriatic arthritis (PsA), arthritis associated with inflammatory bowel disease (SpA-IBD) and reactive arthritis (ReA), reported between 1999 and 2015, were analysed and a control group matched by age, sex and year of admission was selected. Incidence rates for amyloidosis were calculated. Generalised linear models were used for trend analysis and unconditional logistic regression for calculating crude and adjusted ORs (AOR) to assess the association between amyloidosis and SpA.

Results

The study database contained data on 107 140 admissions in each group. Between 1999 and 2015, 792 patients in the SpA cohort (0.7% of all admissions) had a diagnosis of amyloidosis versus 68 in the non-SpA cohort (0.1%) (p<0.001). From 1999 to 2015, incidence rates of amyloidosis tended to decrease in the SpA cohort (−4.63%/year overall), while they increased in the Non-SpA cohort (+10.25%/year overall). We found strong associations of amyloidosis with all SpAs (AOR 10.4; 95% CI 8.2 to 13.3) and with each type studied (AORs 10.05 (7.84 to 12. 88) for AS, 9.5 (7.3 to 12.4) for PsA, 22.9 (16.6 to 31.7) for SpA-IBD and 10.1 (6.1 to 16.7) for ReA).

Conclusions

Incidence of amyloidosis among patients with SpA has strongly decreased in Spain. Amyloidosis is most strongly associated with SpA-IBD while the strength of association with PsA and ReA is similar to that with AS.

A mutation in the SAA1 promoter causes hereditary amyloid A amyloidosis

Amyloid A amyloidosis is a serious clinical condition resulting from the systemic deposition of amyloid A originating from serum amyloid A proteins with the kidneys being the most commonly and earliest affected organ. Previously described amyloid A amyloidosis is linked to increased production and deposition of serum amyloid A proteins secondary to inflammatory conditions arising from infectious, metabolic, or genetic causes. Here we describe a family with primary amyloid A amyloidosis due to a chr11:18287683 T>C (human genome version19) mutation in the SAA1 promoter linked to the amyloidogenic SAA1.1 haplotype. This condition leads to a doubling of the basal SAA1 promoter activity and sustained elevation of serum amyloid A levels that segregated in an autosomal dominant pattern in 12 genetically affected and in none of six genetically unaffected relatives, yielding a statistically significant logarithm of odds (LOD) score over 5. Affected individuals developed proteinuria, chronic kidney disease and systemic deposition of amyloid composed specifically of the SAA1.1 isoform. Tocilizumab (a monoclonal antibody against the interleukin-6 receptor) had a beneficial effect when prescribed early in the disease course. Idiopathic forms represent a significant and increasing proportion (15-20%) of all diagnosed cases of amyloid A amyloidosis. Thus, genetic screening of the SAA1 promoter should be pursued in individuals with amyloid A amyloidosis and no systemic inflammation, especially if there is a positive family history.

Survey of amyloidosis cases among different free-living wild and zoo animals

Amyloidosis comprises a range of protein-folding disorders characterised by a buildup of amyloid deposits in one or multiple organs. The pathogenesis and pathologic findings of amyloidosis can vary widely due to the nature of the precursor protein. In veterinary medicine, there are 10 proteins known to form amyloid deposits in various organs. This review aims to compare amyloidosis cases among different free-living wild and zoo animals focussing in part on the determination of the species particularly susceptible to the amyloid formation and specific prone-to-aggregate protein commonly involved. This review addresses the transmission of AA amyloidosis pertinent to institutions, such as zoos, housing multiple individuals and species in relatively close proximity. In addition, this review includes summarisation for definitive diagnosis of single or multiple cases of amyloidosis affecting free-living wild and zoo animals. Insights into the diversity, transmission, and pathogenesis of known amyloidogenic proteins and species prevalently affected may help to establish a preventive intervention and stimulate the discovery of new diagnostic and therapeutic strategies.

AA Amyloidosis in the Course of HIV Infection: A Report of 19 Cases Including 4 New French Cases and a Comprehensive Review of Literature

INTRODUCTION

HIV infection has been recently retained as an unclear cause of AA amyloidosis. Our aim was to investigate cases of AA amyloidosis associated with HIV infection to understand if it could be considered as a cause of AA amyloidosis.

METHODS

A comprehensive literature review was conducted as well as retrospective study from French cases collected from our national reference center for AA amyloidosis.

RESULTS

Altogether, 19 patients with AA amyloidosis and HIV infection were found with 68% of men and median age at amyloidosis diagnosis of 38 years (range 28-75 years). Clinical presentation was nephrotic syndrome in 94% (n = 17/18). Among patients with renal involvement and assessable outcome (n = 17), 11 (64.7%) progressed to chronic kidney disease, with 6 (35%) end-stage renal disease. Seventy-five percent of patients had uncontrolled HIV infection and 71.4% CD4 counts <400/mm3 at amyloidosis diagnosis. Repeated or chronic bacterial or fungal infection was found in 47% of cases and a history of parenteral drug use in 55% of patients. Three patients had no classical or at least no suspected AA amyloidosis cause found or reported.

CONCLUSIONS

AA Amyloidosis is a rare condition in HIV patients with common renal involvement and significant risk of progression to chronic renal insufficiency. Because of the frequency related to other inflammatory conditions in this population, HIV is probably not an independent risk factor for AA amyloidosis.

Infections and AA amyloidosis: An overview

BACKGROUND

Amyloidoses are a heterogeneous group of systemic diseases characterised by extracellular accumulation of insoluble amyloid fibrils derived from unfolded proteins. Inflammatory (AA) amyloidosis can complicate various inflammatory disorders that are associated with a sustained acute phase response and serum amyloid A (SAA) protein overproduction. Chronic infections were the first recognised cause of amyloidoses. However, with the better management of underlying diseases, the frequency of AA amyloidosis is decreasing.

PURPOSE

The aim of this overview was to discuss the several infections associated with AA amyloidosis and the relative frequency of infections as aetiological factors.

METHODS

A search of the literature was performed using the PubMed database using the MeSH terms "Amyloidosis" and "Infections," from inception to December 31st, 2019. Articles written in other languages than English or French were excluded.

RESULTS

The frequency of AA amyloidosis secondary to infections decreased from more than 50% to less than 20% after the 2000s, with a parallel increase in the frequency of AA amyloidosis secondary to inflammatory diseases and to an unknown cause.

CONCLUSION

Whereas new antibiotics have been developed and sanitary conditions are better, infections still represent 5%-30% of the causes of AA amyloidosis, including in developed countries. These data argue for better screening of chronic infections to prevent AA amyloidosis and the development of new strategies to manage recurrent infections.

Pulmonary amyloidosis mimicking interstitial lung disease and malignancy - A case series with a review of a pulmonary patterns

BACKGROUND

Amyloidosis is an uncommon condition, which results from accumulation of misfolded extracellular insoluble protein in tissues and organs of the body, causing its damage and dysfunction. Histologically, after staining with Congo red, the amyloid deposits show an apple-green birefringence under polarized light microscope. Amyloidosis can affect all organ systems and is classified into hereditary or acquired, localized or systemic. Respiratory involvement occurs in 50% of the patients with amyloidosis and it may take tracheobronchial, nodular parenchymal, diffuse alveolar septal and lymphatic forms.

METHODS

We report four cases of pulmonary amyloidosis. A female patient with localized form of tracheobronchial and nodular parenchymal pulmonary amyloidosis, which was initially misdiagnosed as sarcoidosis. A male patient who was referred to our department for further evaluation of multiple tumors in lungs accompanied by mediastinal lymphadenopathy, liver and peritoneal tumors. A male patient with suspect of lung malignancy. A male patient with diagnosed idiopathic pulmonary fibrosis and the possibility of malignancy.

RESULTS

All the diagnoses were established by demonstration of amyloid protein in tissue specimens obtained in transbronchial or open lung biopsies.

CONCLUSIONS

Due to its nonspecific clinical and radiological findings, amyloidosis can often mimic other diseases and should be considered as one of the differential diagnoses. In order to confirm the diagnosis, proving the presence of amyloid deposition with positive Congo red staining in respiratory specimen is mandatory.

Assessment of Healthcare Professionals' Knowledge and Understanding of the Risk of Blood Typing Interference with Daratumumab: A Survey of 12 European Countries

INTRODUCTION

Daratumumab, a monoclonal antibody targeting CD38, is approved to treat multiple myeloma. Red blood cells express low levels of CD38, which can result in a false-positive antibody screen in daratumumab-treated patients. Educational materials were developed to inform healthcare professionals (HCPs) and blood transfusion management department personnel (BTMDP) about this risk and recommended measures to mitigate that risk. Materials were distributed in European countries where daratumumab was commercially available. This post-authorization safety study was designed to evaluate whether HCPs and BTMDP understood the materials.

METHODS

An anonymous, cross-sectional, non-interventional, web-based survey was distributed in 12 European countries. Four key questions were identified, for which a correct answer from at least 80% of respondents was considered indicative of satisfactory effectiveness.

RESULTS

A total of 408 participants completed the questionnaires (62.3% (n = 254) HCPs and 37.7% (n = 154) BTMDP). Responses were consistent between groups. All respondents were aware of the educational materials (the first key question) and at least 80% correctly answered three of the four key questions. A key question regarding which blood typing test(s) daratumumab interferes with did not achieve satisfactory effectiveness (60% correct responses). In a weighted analysis, 79% of respondents correctly identified the recommended measures for daratumumab-treated patients requiring transfusion. This was attributed to an error in the survey's German translation; in a sensitivity analysis, 90% of participants correctly responded to this question.

CONCLUSIONS

Results suggest that participants were aware of the educational materials, the risk of daratumumab interference with blood testing, and recommended measures to mitigate that risk.

Likelihood of amyloid formation in COVID-19-induced ARDS

Severe coronavirus disease 2019 (COVID-19) infection leads to multifactorial acute respiratory distress syndrome (ARDS), with little therapeutic success. The pathophysiology associated with ARDS or post-ARDS is not yet well understood. We hypothesize that amyloid formation occurring due to protein homeostasis disruption can be one of the complications associated with COVID-19-induced-ARDS.

Differential levels of CHMP2B, LLPH, and SLC25A51 proteins in secondary renal amyloidosis

OBJECTIVES

Renal amyloidosis (RA) is a rare disease, typically manifested with proteinuria, nephrotic syndrome, and ultimately leads to renal failure. The present study aims to profile the proteomes of renal amyloidosis patient's serum and healthy controls, along with relative quantification to find out robust markers for RA.

METHODS

In this study, 12 RA patients and their corresponding age and gender-matched healthy controls were recruited from the Nephrology department of Max Super Specialty Hospital, New Delhi. We employed gel-based proteomic approach coupled with MALDI-TOF MS to compare protein expression patterns in RA patients and controls. Furthermore, validation of differential proteins (selected) was done using bio-layer interferometry.

RESULTS

Eleven proteins showed remarkably altered expression levels. Moreover, expression modulation of three proteins (LLPH, SLC25A51, and CHMP2B) was validated which corroborated with two-dimensional gel electrophoresis (2-DE) results showing significant upregulation (p < 0.05) in RA patients followed by ROC analysis which demonstrated the diagnostic potential of these proteins. A protein-protein master network was generated implicating the above identified proteins along with their interactors, fishing out the routes leading to amyloidosis.

CONCLUSION

This study indicates that the identified serum proteomic signatures could improve early diagnosis and lead to possible therapeutic targets in RA.