Systemic AA amyloidosis: epidemiology, diagnosis, and management

Immunohistochemical typing of amyloid in fixed paraffin-embedded samples by an automatic procedure: Comparison with immunofluorescence data on fresh-frozen tissue

Amyloidosis comprises a spectrum of disorders characterized by the extracellular deposition of amorphous material, originating from an abnormal serum protein. The typing of amyloid into its many variants represents a pivotal step for a correct patient management. Several methods are currently used, including mass spectrometry, immunofluorescence, immunohistochemistry, and immunogold labeling. The aim of the present study was to investigate the accuracy and reliability of immunohistochemistry by means of a recently developed amyloid antibody panel applicable on fixed paraffin-embedded tissues in an automated platform. Patients with clinically and pathologically proven amyloidosis were divided into two cohorts: a pilot one, which included selected amyloidosis cases from 2009 to 2018, and a retrospective one (comprising all consecutive amyloidosis cases analyzed between November 2018 and May 2020). The above-referred panel of antibodies for amyloid classification was tested in all cases using an automated immunohistochemistry platform. When fresh-frozen material was available, immunofluorescence was also performed. Among 130 patients, a total of 143 samples from different organs was investigated. They corresponded to 51 patients from the pilot cohort and 79 ones from the retrospective cohort. In 82 cases (63%), fresh-frozen tissue was tested by immunofluorescence, serving to define amyloid subtype only in 30 of them (36.6%). On the contrary, the automated immunohistochemistry procedure using the above-referred new antibodies allowed to establish the amyloid type in all 130 cases (100%). These included: ALλ (n = 60, 46.2%), ATTR (n = 29, 22.3%), AA (n = 19, 14.6%), ALκ (n = 18, 13.8%), ALys (n = 2, 1.5%), and Aβ₂M amyloidosis (n = 2, 1.5%). The present immunohistochemistry antibody panel represents a sensitive, reliable, fast, and low-cost method for amyloid typing. Since immunohistochemistry is available in most pathology laboratories, it may become the new gold standard for amyloidosis classification, either used alone or combined with mass spectrometry in selected cases.

The risk, predictors, and outcomes of amyloidosis in ankylosing spondylitis: a longitudinal population-based cohort study

OBJECTIVE

The risk of amyloidosis during the course of ankylosing spondylitis (AS) is yet to be firmly established. We aimed to evaluate the risk, predictors, and prognostic outcomes of amyloidosis among patients with AS.

METHODS

A population-based cohort study was conducted comparing AS patients (n = 5,911) with age-, sex- and ethnicity-matched control subjects (n = 29 007) with regard to incident cases of amyloidosis. Hazard ratios (HRs) and odds ratios (ORs) were estimated by Cox regression and logistic regression analyses, respectively.

RESULTS

The incidence rate of amyloidosis was 2.15 (95% CI, 1.09-2.82) and 0.35 (95% CI, 0.16-0.66) per 10 000 person-years among patients with AS and controls, respectively. The risk of incident amyloidosis was >6-folds higher among patients with AS relative to control subjects (adjusted HR, 6.16; 95% CI, 2.43-15.62; p< 0.001). A higher comorbidity burden (OR, 1.36; 95% CI, 1.08-1.73; p= 0.010) was found to predict an increased susceptibility to amyloidosis in AS patients. Compared with other patients with AS, those with AS and comorbid amyloidosis had a 14-fold increased risk of end-stage renal disease necessitating dialysis (adjusted HR, 14.7; 95% CI, 2.0-107.2; p= 0.008), but comparable risk of all-cause mortality (adjusted HR, 2.16; 95% CI, 0.69-6.71; p= 0.174).

CONCLUSIONS

Patients with AS are at an increased risk of amyloidosis. AS-associated amyloidosis is associated with an elevated risk of dialysis dependence. Awareness of the burden and consequences of this complication may be of help for rheumatologists managing patients with AS.

Emerging role of metabolomics in protein conformational disorders

Introduction: Metabolomics focuses on interactions among different metabolites associated with various cellular functions in cells, tissues, and organs. In recent years, metabolomics has emerged as a powerful tool to identify perturbed metabolites, pathways influenced by the environment, for protein conformational diseases (PCDs) and also offers wide clinical application.Area Covered: This review provides a brief overview of recent advances in metabolomics as applied to identify metabolic variations in PCDs, such as Alzheimer's disease, Parkinson's disease, Huntington's disease, prion disease, and cardiac amyloidosis. The 'PubMed' and 'Google Scholar' database search methods have been used to screen the published reports with key search terms: metabolomics, biomarkers, and protein conformational disorders.Expert opinion: Metabolomics is the large-scale study of metabolites and is deemed to overwhelm other omics. It plays a crucial role in finding variations in diseases due to protein conformational changes. However, many PCDs are yet to be identified. Metabolomics is still an emerging field; there is a need for new high-resolution analytical techniques and more studies need to be carried out to generate new information.

Localized plantar amyloidosis: case report and review of the literature

Amyloidosis may be hereditary or acquired and the deposits can be focal, localized, or systemic in distribution. A discrete mass of amyloid deposition is called an amyloidoma and is the least common presentation. Soft tissue amyloidoma in an extremity is exceedingly rare. Amyloidomas can mimic malignant neoplasms both clinically and radiologically. We report a case of an amyloidoma in the foot, which has not been previously described. Clinical history, pathology, and immunohistochemistry and appearance by MRI are described. Knowledge of this atypical lesion, in its various forms, is important for experts in musculoskeletal radiology, pathology, surgery, and oncology to appreciate as it can prevent confusion with more sinister disease processes such as malignancy. Early recognition can help guide appropriate management in a timely fashion.

Two cases of secondary AA amyloidosis involving the skin and chronic kidney infection with a nephrotic syndrome in a high-income country

We present two French cases of amyloid-associated (AA) amyloidosis secondary to chronic infections. Patient 1, a 51-year-old heroin addict, was hospitalised for chest pain and anasarca. During hospitalisation, a nephrotic syndrome with an inflammatory condition was discovered along with a chronic skin ulcer on his arm. Salivary gland and kidney biopsies confirmed the diagnosis of AA amyloidosis. Renal function quickly declined and haemodialysis was initiated 6 months later. Patient 2, a 55-year-old woman, was hospitalised for obstructive pyelonephritis secondary to coraliform lithiasis. Renal insufficiency with an impure nephrotic syndrome was found. After nephrectomy due to chronic pyelonephritis and an atrophic cortex on the abdominal scan, the histology revealed AA amyloidosis. Despite treatment with ACE inhibitors and control of inflammation, the nephrotic syndrome persisted with rapid decline of the kidney function.

Renal transplant outcomes in amyloidosis

BACKGROUND

Outcomes after renal transplantation have traditionally been poor in systemic amyloid A (AA) amyloidosis and systemic light chain (AL) amyloidosis, with high mortality and frequent recurrent disease. We sought to compare outcomes with matched transplant recipients with autosomal dominant polycystic kidney disease (ADPKD) and diabetic nephropathy (DN), and identify factors predictive of outcomes.

METHODS

We performed a retrospective cohort study of 51 systemic AL and 48 systemic AA amyloidosis patients undergoing renal transplantation. Matched groups were generated by propensity score matching. Patient and death-censored allograft survival were compared via Kaplan-Meier survival analyses, and assessment of clinicopathological features predicting outcomes via Cox proportional hazard analyses.

RESULTS

One-, 5- and 10-year death-censored unadjusted graft survival was, respectively, 94, 91 and 78% for AA amyloidosis, and 98, 93 and 93% for AL amyloidosis; median patient survival was 13.1 and 7.9 years, respectively. Patient survival in AL and AA amyloidosis was comparable to DN, but poorer than ADPKD [hazard ratio (HR) = 3.12 and 3.09, respectively; P < 0.001]. Death-censored allograft survival was comparable between all groups. In AL amyloidosis, mortality was predicted by interventricular septum at end diastole (IVSd) thickness >12 mm (HR = 26.58; P = 0.03), while survival was predicted by haematologic response (very good partial or complete response; HR = 0.07; P = 0.018). In AA amyloidosis, recurrent amyloid was associated with elevated serum amyloid A concentration but not with outcomes.

CONCLUSIONS

Renal transplantation outcomes for selected patients with AA and AL amyloidosis are comparable to those with DN. In AL amyloidosis, IVSd thickness and achievement of deep haematologic response pre-transplant profoundly impact patient survival.

Secondary Amyloidosis Presenting as Ischemic Proctitis

A 49-year-old man presented with abdominal pain and rectal bleeding for two days associated with a 50-pound unintentional weight loss. History was notable for hypertension, chronic kidney disease, obesity, gout, and acute cholecystitis status post cholecystectomy. Computed tomography (CT) of the abdomen and pelvis showed rectal wall thickening. Colonoscopy showed proctitis with superficial ulcerations. In the setting of renal insufficiency, malabsorption, and low-voltage QRS complexes on electrocardiogram (ECG), amyloidosis was considered in the differential diagnosis. Rectal and renal biopsies with subsequent retrospective staining of gallbladder tissue confirmed amyloid deposition. Gastrointestinal involvement of amyloidosis is relatively uncommon. Particularly, amyloid deposition in the gallbladder and rectum is very rare. The development of AA amyloidosis in our patient may have been related to gout, obesity, and the presence of a heterozygous complex variant for the MEFV (familial Mediterranean fever) gene. Awareness of this atypical presentation of amyloidosis is important, as additional staining of biopsy samples is necessary, and diagnosis allows for directed treatment.

Amyloidosis in the Bulbar Conjunctiva Following Transconjunctival Ptosis Surgery

ABSTRACT

A 52-year-old woman presented with persistent eye irritation following her third transconjunctival ptosis surgery. Examination revealed a yellow-pink nodular lesion in the bulbar conjunctiva. Excision biopsy and histopathology showed granulation tissue. However, the tumor recurred 1 month postoperatively. Repeat biopsy and histopathology revealed amyloid deposits. Systemic work-up showed no other lesion. A retained suture found in the upper fornix was also removed. No tumor recurrence has since been noted over the 7-month follow-up period. This report aims to highlight a case of bulbar conjunctival amyloidosis that developed as a complication following multiple transconjunctival eyelid surgeries.

Laryngotracheobronchial amyloidosis: A case report

Primary laryngotracheobronchial amyloidosis is a rare pulmonary disease that can cause endobronchial stenosis. This disease has never previously been reported in Vietnam. We aimed to report a laryngotracheobronchial amyloidosis case in a 43-year-old female, which may be the first reported case in Vietnam. The patient had a 4-year history of progressive hoarseness, dyspnea, and hemoptysis. Multiple bronchial biopsies combined with detailed clinical information suggested an amyloidosis disease. Red congo staining was positive in bronchial samples, and a further workup found positive red congo staining in subcutaneous fatty tissue biopsy samples. Tracheostomy was performed due to severe dyspnea related to laryngeal stenosis. A multidisciplinary consultation was held, and chemotherapy with melphalan and dexamethasone were prescribed due to the systemic effects of the disease. After 2 cycles of chemotherapy, the patient showed improvement in dyspnea and cough. Due to the inexperience of both the clinicians and pathologists, this case was diagnosed quite late. In the future, if this diagnosis is considered in the differential diagnosis, an earlier diagnosis and better treatment outcome can be reached.

Serum amyloid A concentrations, COVID-19 severity and mortality: An updated systematic review and meta-analysis

BACKGROUND AND OBJECTIVES

An excessive inflammatory response in patients with coronavirus disease 2019 (COVID-19) is associated with high disease severity and mortality. Specific acute phase reactants might be useful for risk stratification. A systematic review and meta-analysis was conducted of studies on serum amyloid A (SAA) in patients with COVID-19.

METHODS

The PubMed, Web of Science, and Scopus databases were searched, covering the period January 2020 to December 2020, for studies reporting SAA concentrations, COVID-19 severity, and survival status.

RESULTS

Nineteen studies involving 5617 COVID-19 patients were included in the meta-analysis. Pooled results showed that SAA concentrations were significantly higher in patients with severe disease and non-survivors (standard mean difference (SMD) 1.20, 95% confidence interval 0.91-1.49, P < 0.001). Extreme between-study heterogeneity was observed (I² = 92.4%, P < 0.001). In the sensitivity analysis, the effect size was not significantly affected when each study was removed in turn (range 1.10-1.29). The Begg test (P = 0.030), but not the Egger test (P = 0.385), revealed the presence of publication bias. Pooled SMD values were significantly and positively associated with sex (t = 2.20, P = 0.047) and aspartate aminotransferase (t = 3.44, P = 0.014).

CONCLUSIONS

SAA concentrations were significantly and positively associated with higher COVID-19 severity and mortality. This acute phase reactant might assist with risk stratification and monitoring in this group.

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.

Gout and AA-Amyloidosis: A Case-Based Review

Background:

AA-amyloidosis complicates many chronic infections and inflammatory diseases, including rheumatoid arthritis, ankylosing spondylitis, and psoriatic arthritis, but its relationship to gout is extremely rare. As it is unknown definitely what the pathophysiological connections between gout and amyloidosis are, treatment issues of the diseases are open for discussion.

Aim:

To establish a link between gout and AA-amyloidosis, and to improve the quality of treatment in patients suffering from gout and AA-amyloidosis.

Methods:

We reviewed the English-language literature sources, searching not only for rare cases of the combination of gout and AA amyloidosis, but also detailed descriptions of the medical treatments for the two pathologies.

Results:

By July 2020, we had identified 14 cases describing AA amyloidosis in patients with gout. Most of those patients had been suffering tophaceous gout for at least 10 years, and were prescribed various methods of treatment; however, not all patients took colchicine regularly. In some cases, therapy with allopurinol and colchicine was effective against attacks of gouty arthritis, although amyloidogenic inflammation was not controlled sufficiently. However, there were no cases that described in detail the successful treatment of both diseases. Besides those 14 patients described in literature, we examined one more patient with amyloidosis that is secondary to gout, in whom the protein of amyloid A (AA) had affected the kidneys, intestines, and adrenal glands. The patient has been successfully treated with the combination of canakinumab, prednisone, colchicine and allopurinol.

Conclusion:

Clinicians should be aware that patients may have atypical combinations of diseases like gout and amyloidosis. The obtained results help to explain some pathogenic processes associated with AA-amyloidosis. Further research is necessary to confirm the effectiveness of different treatment options such as lifestyle biologic agents or other medicines with anti-inflammatory properties.

AA Amyloidosis Secondary to Primary Immune Deficiency: About 40 Cases Including 2 New French Cases and a Systematic Literature Review

BACKGROUND

Primary immune deficiencies (PIDs) are a heterogeneous group of disorders resulting from defects in immune system. They lead to increased susceptibility to infections and immune dysregulation. The resulting chronic inflammation can induce long-term complications, including AA amyloidosis (AAA).

OBJECTIVES

To present the French cases of PID-related AAA and perform a systematic literature review to determine its main features and predisposing factors.

METHODS

A systematic literature review was performed by searching MEDLINE up until 2019. New French cases were identified with the help of the Reference Center for Auto-Inflammatory Diseases and AA Amyloidosis and the Reference Center for Hereditary Immune Deficiencies.

RESULTS

Forty patients were identified including 2 new French cases. PIDs were varied: immunoglobulin deficits (n = 30), chronic granulomatous disease (n = 3), hyper-IgM syndrome (n = 3), hereditary complete C4 deficiency (n = 1), leucocyte adhesion deficiency type 1 (n = 1), hyper-IgE syndrome (n = 1), and Chediak-Higashi syndrome (n = 1). The mean age at PID diagnosis was 22.2 ± 16.02 years. Renal involvement was the most common manifestation of AAA (80%). Infections were extremely heterogeneous; bacterial infection with pulmonary involvement was the most frequent. Bronchiectasis was particularly common (52.5%). The delay between the first symptoms of PID and AAA diagnosis was 16.18 ± 7 years. Thirteen concomitant diagnoses were made. Twenty patients died during follow-up.

CONCLUSION

AAA is a rare life-threatening complication of PID, especially in cases of long diagnostic and therapeutic delays. Bronchiectasis should be considered as a warning sign of chronic inflammation and increased risk of AAA.

Diagnosis and treatment of cardiac amyloidosis: position statement of the German Cardiac Society (DGK)

Systemic forms of amyloidosis affecting the heart are mostly light-chain (AL) and transthyretin (ATTR) amyloidoses. The latter is caused by deposition of misfolded transthyretin, either in wild-type (ATTRwt) or mutant (ATTRv) conformation. For diagnostics, specific serum biomarkers and modern non-invasive imaging techniques, such as cardiovascular magnetic resonance imaging (CMR) and scintigraphic methods, are available today. These imaging techniques do not only complement conventional echocardiography, but also allow for accurate assessment of the extent of cardiac involvement, in addition to diagnosing cardiac amyloidosis. Endomyocardial biopsy still plays a major role in the histopathological diagnosis and subtyping of cardiac amyloidosis. The main objective of the diagnostic algorithm outlined in this position statement is to detect cardiac amyloidosis as reliably and early as possible, to accurately determine its extent, and to reliably identify the underlying subtype of amyloidosis, thereby enabling subsequent targeted treatment.

Gastrointestinal amyloidosis: A focused review

Amyloidosis, a heterogenous group of disorders, is characterized by the extracellular deposition of autologous, insoluble, fibrillar misfolded proteins. These extracellular proteins deposit in tissues aggregated in ß-pleated sheets arranged in an antiparallel fashion and cause distortion to the tissue architecture and function. In the current literature, about 60 heterogeneous amyloidogenic proteins have been identified, out of which 27 have been associated with human disease. Classified as a rare disease, amyloidosis is known to have a wide range of possible etiologies and clinical manifestations. The exact incidence and prevalence of the disease is currently unknown. In both systemic and localized amyloidosis, there is infiltration of the abnormal proteins in the layers of the gastrointestinal (GI) tract or the liver parenchyma. The gold standard test for establishing a diagnosis is tissue biopsy followed by Congo Red staining and apple-green birefringence of the Congo Red-stained deposits under polarized light. However, not all patients may have a positive tissue confirmation of the disease. In these cases additional workup and referral to a gastroenterologist may be warranted. Along with symptomatic management, the treatment for GI amyloidosis consists of observation or localized surgical excision in patients with localized disease, and treatment of the underlying pathology in cases of systemic amyloidosis. In this review of the literature, we describe the subtypes of amyloidosis, with a primary focus on the epidemiology, pathogenesis, clinical features, diagnosis and treatment strategies available for GI amyloidosis.

Stability of Human Serum Amyloid A Fibrils

In systemic amyloidosis, serum amyloid A (SAA) fibril deposits cause widespread damages to tissues and organs that eventually may lead to death. A therapeutically intervention therefore has either to dissolve these fibrils or inhibit their formation. However, only recently has the human SAA fibril structure been resolved at a resolution that is sufficient for development of drug candidates. Here, we use molecular dynamic simulations to probe the factors that modulate the stability of this fibril model. Our simulations suggest that fibril formation starts with the stacking of two misfolded monomers into metastable dimers, with the stacking depending on the N-terminal amyloidogenic regions of different chains forming anchors. The resulting dimers pack in a second step into a 2-fold two-layer tetramer that is stable enough to nucleate fibril formation. The stability of the initial dimers is enhanced under acidic conditions by a strong salt bridge and side-chain hydrogen bond network in the C-terminal cavity (residues 23-51) but is not affected by the presence of the disordered C-terminal tail.

Tailoring biologic therapy for real-world rheumatoid arthritis patients

Introduction: The cornerstone of rheumatoid arthritis (RA) therapy relies on the treat-to-target strategy, which aims at dampening inflammation as soon as possible in order to achieve persistent low disease activity or, ideally, remission, according to validated disease activity measures. Traditional disease-modifying antirheumatic drugs (DMARDs) may be chosen in monotherapy or in combination as first-line therapy; in case of an unsatisfactory response after a 3-6-month trial, biologic therapy may be commenced.Areas covered: Real-life RA patients may present with concomitant comorbidities/complications or be in peculiar physiological states which raise more than one question as to which biotherapy may be more well suited considering the whole clinical picture. Therefore, a thorough literature search was performed to identify the most appropriate biologic therapy in each setting considered in this review.Expert opinion: Here we provide suggestions for the use of biologic drugs having a predictable better outcome in specific real-world conditions, so as to ideally profile the patient to the best of the current knowledge.

Malabsorption Syndrome due to Intestinal Amyloidosis as Presentation of Renal Cell Carcinoma

Renal cell carcinoma accounts for approximately 3% of adult malignancies. Designated in the literature as "the great masquerader," the great diversity of clinical manifestations is associated with the several paraneoplastic syndromes that potentially accompany it. Paraneoplastic amyloidosis is described in about 3-8% of cases, only exceptionally as an initial manifestation, with uncommon gastrointestinal involvement. A rare case of malabsorption by intestinal amyloidosis is presented as initial manifestation of renal cell carcinoma, emphasizing the need for early recognition of these paraneoplastic conditions.

Renal amyloidosis: an update on diagnosis and pathogenesis

Amyloidosis is a diverse group of protein conformational disorder which is caused by accumulation and deposition of insoluble protein fibrils in vital tissues or organs, instigating organ dysfunction. Renal amyloidosis is characterized by the acellular Congo red-positive pathologic deposition of amyloid fibrils within glomeruli and/or the interstitium. It is generally composed of serum amyloid A-related protein or an immunoglobulin light chain; other rare forms lysozyme, gelsolin, fibrinogen alpha chain, transthyretin, apolipoproteins AI/AII/AIV/CII/CIII; and the recently identified form ALECT2. This disease typically manifests with heavy proteinuria, nephrotic syndrome, and finally progression to end-stage renal failure. Early diagnosis of renal amyloidosis is arduous as its symptoms appear in later stages with prominent amyloid deposition. The identification of the correct type of amyloidosis is quite troublesome as it can be confused with another related form. Therefore, the exact typing of amyloid is essential for prognosis, treatment, and correct management of renal amyloidosis. The emanation of new techniques of proteomic analysis, for instance, mass spectroscopy/laser microdissection, has provided greater accuracy in amyloid typing. This in-depth review emphasizes on the clinical features, renal pathological findings, and diagnosis of the AL and non-AL forms of renal amyloidosis.

Gastric AA amyloidosis secondary to chronic infection presenting with hematemesis: a case report

AA amyloidosis, previously known as secondary amyloidosis, has been associated with multiple chronic inflammatory conditions, including various autoimmune diseases and rarely chronic infection. Hereby, we present a case of AA amyloidosis secondary to chronic infection which initially presented with nausea and hematemesis. Endoscopic biopsies revealed diffuse AA amyloid deposition in the stomach, but not the esophagus. AA Amyloidosis presumably compromised gastric motility, promoted reflux related esophageal ulcers and erosions, and caused his cardiac and renal insufficiency. Therefore, endoscopic biopsies could be practical investigation to identify AA amyloidosis in the setting of chronic inflammatory diseases, especially with multi-organ involvement.

Amyloid Proteins and Peripheral Neuropathy

Painful peripheral neuropathy affects millions of people worldwide. Peripheral neuropathy develops in patients with various diseases, including rare familial or acquired amyloid polyneuropathies, as well as some common diseases, including type 2 diabetes mellitus and several chronic inflammatory diseases. Intriguingly, these diseases share a histopathological feature-deposits of amyloid-forming proteins in tissues. Amyloid-forming proteins may cause tissue dysregulation and damage, including damage to nerves, and may be a common cause of neuropathy in these, and potentially other, diseases. Here, we will discuss how amyloid proteins contribute to peripheral neuropathy by reviewing the current understanding of pathogenic mechanisms in known inherited and acquired (usually rare) amyloid neuropathies. In addition, we will discuss the potential role of amyloid proteins in peripheral neuropathy in some common diseases, which are not (yet) considered as amyloid neuropathies. We conclude that there are many similarities in the molecular and cell biological defects caused by aggregation of the various amyloid proteins in these different diseases and propose a common pathogenic pathway for "peripheral amyloid neuropathies".

The diagnostic challenges of cardiac amyloidosis: A practical approach to the two main types

Systemic amyloidosis of the immunoglobulin light-chain (AL) or transthyretin type (ATTR) is a multisystem protein deposition disease that often involves the heart. Delays in diagnosis are very common and can have detrimental consequences on patient outcomes. Because both major types can now be distinguished quickly and treated effectively, clear approaches are required. There have been advances in radioisotope scintigraphy, monoclonal protein testing and mass spectrometry for typing that need coordinated application. We have entered an era in which rapid diagnosis and ready therapy will save lives, therefore we must develop coherent approaches to this multisystem disease. The prognosis for AL has improved significantly with the incorporation of novel agents such as proteasome inhibitors, immunomodulators and monoclonal antibodies against plasma cells. Multiple independent studies have demonstrated the efficacy of these agents in AL, though tolerability can become an issue with dose reductions required in many cases. Median overall survival for patients achieving complete responses after stem cell transplant and consolidation exceeds a decade. The prognosis for ATTR, both age-related wild-type (ATTRwt) and hereditary due to variants of transthyretin (ATTRv), has improved as well due to the availability of the stabilizer tafamidis and the RNA-interference agents patisiran and inotersen. In both AL and ATTR, with elimination or suppression of the pathologic amyloid-forming protein, symptomatic involvement of the heart, kidneys and peripheral nervous system can improve as well. In this review, we present the current state of diagnosing and treating the two major types of systemic amyloidosis, emphasizing the coherent clinical application of the new tools and treatments. Implementation of the approaches we provide will enable rapid identification of amyloid type and rational selection of therapy.

Soluble tumour necrosis factor-alpha receptor improved the function, hypertrophy, and granular sparkling appearance of the left ventricular myocardium in systemic amyloid A amyloidosis: a case report

Background

About 7% of amyloid A (AA) amyloidosis cases are accompanied by heart disease. Although several studies have recently reported that specific biologicals improved renal function in AA amyloidosis, little evidence is available regarding heart disease in AA amyloidosis.

Case summary

A 57-year-old woman with rheumatoid arthritis presented with sudden worsening of renal function. Echocardiography revealed granular sparkling appearance in the ventricular septum and posterior wall (PW). Echocardiography indicated left ventricular (LV) diastolic dysfunction. Global longitudinal strain (GLS) exhibited an apical sparing pattern. Cardiac biopsy demonstrated amyloid A deposition on immunostaining. Soluble tumour necrosis factor-alpha receptor etanercept therapy was initiated. Four years later, echocardiography showed improved diastolic function, including E/A and E/e’, and decreased wall thickness in both the interventricular septum and PW of the left ventricle. Granular sparkling appearance had diminished. Moreover, the LV dysfunction improved on GLS. Five years later, the medication was gradually losing effect and the patient had worsening pain in the joints; moreover, articular destruction was observed on radiography. The patient was switched to abatacept therapy. Echocardiography showed recurrence of LV hypertrophy and electrocardiogram showed down-sloped ST depression in V4–6 leads.

Discussion

This case indicates that etanercept can be effective for heart disease in AA amyloidosis. Of particular, interest is the improvement of granular sparkling appearance in addition to cardiac function improvement noted in this case.

Mesenteric Amyloidosis: Radiologic Imaging with Pathologic Correlation

Amyloidosis is a rare disease that is characterized by abnormal deposition of amyloid proteins in tissues, resulting in local, or systemic disease. When localized, it can present as an amyloidoma. We report a case of mesenteric amyloidosis in an 80-year-old male who was found to have an incidental mesenteric mass that was biopsy-proven to represent non-light chain amyloid tissue.

Cleavage, Downregulation, and Aggregation of Serum Amyloid A

Various diseases cause overexpression of the serum amyloid A (SAA) protein, which in some cases, but not in all cases, leads to amyloidosis as a secondary disease. Response to the overexpression involves dissociation of the SAA hexamer and subsequent cleavage of the released monomers, most commonly yielding fragments SAA_1-76 of the full-sized SAA_1-104. We report results from molecular dynamic simulations that probe the role of this cleavage for downregulating the activity and concentration of SAA. We propose a mechanism that relies on two elements. First, the probability to assemble into hexamers is lower for the fragments than it is for the full-sized protein. Second, unlike other fragments, SAA_1-76 can switch between two distinct configurations. The first kind is easy to proteolyse (allowing a fast reduction of the SAA concentration) but prone to aggregation, whereas the situation is opposite for the second kind. If the time scale for amyloid formation is longer than the one for proteolysis, the aggregation-prone species dominates. However, if environmental conditions such as low pH increases the risk of amyloid formation, the ensemble shifts toward the more protected form. We speculate that SAA amyloidosis is a failure of this switching mechanism leading to accumulation of the aggregation-prone species and subsequent amyloid formation.

Lacrimal Gland Amyloidosis in an Elderly Patient

Localized amyloidosis of the lacrimal gland is a rare disease. We report a case of transthyretin-positive localized amyloidosis of the lacrimal gland in a 74-year-old man with left lacrimal gland swelling. Biopsy of the left lacrimal gland showed extensive deposition of nonstructural eosinophilic material in the secretory gland and ducts, which stained positive with direct fast scarlet. Immunostaining was negative for amyloid A and positive for both globulin light chain (kappa, lambda) and transthyretin. It is necessary to consider the possibility of senile systemic amyloidosis, even if localized amyloidosis of the lacrimal gland is suspected.

Serum amyloid A-type amyloidosis of the kidney and immune complex-mediated glomerulopathy in the setting of hyperimmunoglobulin E (Job's) syndrome

Hyperimmunoglobulin E syndrome (HIES) is a rare immunodeficiency syndrome with characteristic features of pulmonary infections, eczema, recurrent skin abscesses and elevated serum IgE. We present a case of an HIES patient referred for nephrology consultation with elevated serum creatinine and nephrotic-range proteinuria. The subsequent kidney biopsy revealed AA-type amyloidosis and a separate and distinct inactive immune complex-mediated glomerulopathy with frequent glomerular capillary wall and mesangial polyclonal deposits. Potential kidney pathology in the setting of HIES has not been well described previously, and this case provides insight into associated renal comorbidities faced by patients with this rare syndrome.

Hiding in Plain Sight: Cardiac Amyloidosis, an Emerging Epidemic

Amyloidosis is a term used to describe a group of rare heterogeneous diseases that ultimately result in the deposition and accumulation of misfolded proteins. These misfolded proteins, known as amyloids, are associated with a variety of precursor proteins that have amyloidogenic potential. Ultimately, the specific type of amyloidosis is dependent on multiple factors including genetic variability of precursor proteins and the tissue or organ in which the amyloid accumulates. Several types of amyloid have a predilection for the heart and thus contribute to cardiac amyloidosis, a major cause of restrictive cardiomyopathy. Individuals with cardiac amyloidosis present clinically with heart failure with preserved ejection fraction. Although improved diagnostics and increased awareness of cardiac amyloidosis have led to a relative increase in diagnosis, cardiac amyloidosis remains an underrecognized and underdiagnosed cause of heart failure with preserved ejection fraction. It is essential to properly identify cases of cardiac amyloidosis and determine the pathology responsible for the formation of amyloid to appropriately provide management. This review aims to encourage physician awareness of cardiac amyloidosis by focusing on clinical presentation and the distinctions between types. Furthermore, epidemiology is central to understanding the affected demographics and sometimes hereditary nature of the disease. Improved understanding of cardiac amyloidosis will ideally lead to earlier diagnosis and interventions to improve patient outcomes.

Lactobacillus Endocarditis-Associated Glomerulonephritis Complicated by anti-Coagulant Nephropathy and Renal Amyloidosis

Kidney injury is a well-known sequelae of infectious endocarditis. Various types of kidney injury can be seen, including endocarditis-associated glomerulonephritis, and may affect nearly half of the patients with infectious endocarditis. Lactobacillus species are an infrequently documented cause of endocarditis. We present a case of Lactobacillus endocarditis-associated glomerulonephritis in a patient with a complex medical history including Lactobacillus infection of an artificial heart valve. To our knowledge, this is the first reported case of development of endocarditis-associated glomerulonephritis secondary to Lactobacillus species organisms. Furthermore, the patient's renal biopsy revealed several frequently overlooked concomitant findings including anti-coagulant nephropathy and renal amyloidosis.

Pattern of renal amyloidosis in South Africa

Background

Kidney disease is a serious manifestation of systemic amyloidosis and a major cause of morbidity and mortality. Tuberculosis (TB) occurs up to 27 times more commonly in human immunodeficiency virus (HIV) infected patients and is also an important cause of renal amyloid; there are however no reports of renal amyloidosis in South Africa in the HIV era.

Methods

This was a retrospective record review of cases of amyloidosis diagnosed on renal biopsies at our tertiary referral hospital between January 1985 and December 2016.

Results

Forty-six cases of amyloidosis were identified over the study period. The calculated biopsy prevalence was 1.38 per 100 non-transplant renal biopsies (95% Confidence Interval 1.02–1.86). AL amyloidosis was identified in 26 (57%) cases and AA in 20 (43%). The median age at presentation was 51 years and 52% of cases were female. Patients with AA amyloidosis were significantly younger compared to their AL counterparts (age 42 years vs. 58 years, p = < 0.001) and were all significantly non-white. The main clinical presentation was nephrotic syndrome (85%) and 52% of cases also had a serum creatinine value of greater than 120 μmol/L. Of the 20 cases of AA amyloidosis, 12 (60%) were associated with tuberculosis. HIV infection was noted in only two (10%) of the 20 AA cases. Median survival after diagnosis was 2 months.

Conclusion

Amyloidosis is a rare cause of kidney disease and typically presents with nephrotic syndrome. A similar number of AA and AL types were observed, and outcomes are worse in cases of AA amyloid. While TB remains the major underlying disease in this type, HIV infection was infrequent in cases of AA renal amyloidosis.

An Organ System-Based Approach to Differential Diagnosis of Amyloid Type in Surgical Pathology

CONTEXT.—

Amyloidosis is an uncommon but important entity. A protein-based classification of amyloidosis defines the underlying disease process, directing clinical management and providing prognostic information. However, in routine surgical pathology there often is no attempt to classify amyloid other than staining to determine light chain-associated amyloidosis. Systemic and localized amyloidosis vary with respect to frequency of organ involvement by different amyloid types, and most amyloid proteins have commercial antibodies available for identification.

OBJECTIVE.—

To provide a guide for the likelihood of amyloid type by organ system.

DATA SOURCES.—

Literature review based on PubMed searches containing the word amyloid, specifically addressing the prevalence and significance of amyloid proteins in each organ system other than the brain, and the authors' practice experience.

CONCLUSIONS.—

In patients with amyloidosis, determination of the responsible protein is critical for appropriate patient care. In large subspecialty practices and reference laboratories with experience in using and analyzing relevant immunohistochemistry, most amyloid proteins can be identified with an organ-specific algorithm. Referring to an organ-based algorithm may be helpful in providing clinicians with a more specific differential diagnosis regarding amyloid type to help guide clinical evaluation and treatment. When the protein cannot be characterized, mass spectrometry can be performed to definitively classify the amyloid type.

Morphological and primary structural consistency of fibrils from different AA patients (common variant)

Aims: To test the hypothesis that the fibril morphology and the fibril protein primary structure are conserved across different patients suffering from the common variant of systemic Amyloid A (AA) amyloidosis. Methods: Amyloid fibrils were extracted from the renal tissue of four patients. The fibril morphology was analysed in negatively stained samples with transmission electron microscopy (TEM). The fibril protein identity and fragment length were determined by using mass spectrometry. Results: The fibrils show a consistent morphology in all four patients and exhibit an average width of ∼9.6 nm and an average pitch of ∼112 nm. All fibrils are composed of polypeptide chains that can be assigned to human serum amyloid A (SAA) 1.1 protein. All fragments lack the N-terminal arginine residue and are C-terminally truncated. Differences exist concerning the exact C-terminal cleavage site. The most prominent cleavage site occurs at residues 64-67. Conclusions: Our data demonstrate that AA amyloid fibrils are consistent at the level of the protein primary structure and fibril morphology in the four analysed patients.

Yellow subconjunctival deposits

In this case report, we present a healthy man who was referred for removal of subconjunctival yellow lesions found during a routine eye examination. In histopathological examination, an amyloidosis was found. There were no remnants or new lesions during 1-year follow-up. There was no systemic involvement. Conjunctival amyloidosis is a rare diagnosis that often is overlooked. Failure to recognise conjunctival amyloidosis might lead to late diagnosis of systemic amyloidosis. This case may rise the awareness to this rare diagnosis.

Chronic Oral Exposure to Synthetic Amorphous Silica (NM-200) Results in Renal and Liver Lesions in Mice

Introduction

Silicon dioxide, produced as synthetic amorphous silica (SAS), is made of nanoparticles (NPs), either present as such or as agglomerates and aggregates, and is widely used in many types of food processes and products as an additive. To assess whether repeated, long-term exposure to SAS NPs may result in adverse effects, mice were exposed for 18 months via drinking water to NM-200, one of the reference nanostructured silica used for applications related to food, at 4.8 mg NM-200/kg body weight per day, a dose relevant to the estimated dietary exposure to SAS in humans.

Methods

The experiment focused on the kidney and liver as target organs and was carried out in parallel using 3 mouse lines (wild type and transgenic) differing for the expression of α-synuclein, that is, murine and human mutated (A53T). Sensitive determination of silicon revealed higher contents in liver and kidneys of NM-200–exposed mice compared with unexposed aged-matched controls.

Results

Histological abnormalities, such as vacuolization of tubular epithelial cells, were detected in all kidneys, as well as inflammatory responses that were also detected in livers of exposed animals. Less frequent but more deleterious, amyloidosis lesions were observed in glomeruli, associated with perivascular amyloid accumulation in liver.

Conclusion

These histological findings, in conjunction with the observation of detectable deposition of silica, highlight that chronic oral intake of SAS may pose a health risk to humans and need to be examined further.

Assessment of Mean Platelet Volume in Patients with AA Amyloidosis and AA Amyloidosis Secondary to Familial Mediterranean Fever: A Retrospective Chart - Review Study

Background

Amyloidosis is a protein-misfolding disease characterized by the deposition of aggregated proteins in the form of abnormal fibrils that disrupt tissue structure, ultimately causing disease. Amyloidosis is very frequent in untreated familial Mediterranean fever (FMF) patients and it is the most important feature that determines the prognosis of FMF disease. The mean platelet volume (MPV) in FMF has been previously studied. However, whether MPV level in FMF patients is lower or higher compared to healthy controls remains a topic of ongoing debate. In this study, we aimed to investigate MPV values and to assess the correlation between MPV and proteinuria in patients with AA amyloidosis and AA amyloidosis secondary to familial Mediterranean fever (AA-FMF) through a retrospective chart-review.

Material/Methods

This study was carried out on 27 patients with AA amyloidosis, 36 patients with AA amyloidosis secondary to FMF (a total of 63 patients with AA), and 29 healthy controls. There was no statistically significant difference between the AA patients and the control group (p=0.06) or between the AA-FMF group and the control group in terms of MPV values (p=0.12).

Results

We found a statistically significant negative correlation between MPV and thrombocyte count in all groups (p<0.05 for all groups), but there was no correlation between MPV and proteinuria levels in AA patients (p=0.091).

Conclusions

While similar results also exist, these findings are contrary to the majority of previous studies. Therefore, further controlled clinical prospective trials are necessary to address this inconsistency.

Mucocutaneous manifestations in systemic amyloidosis A retrospective analytical study in a tertiary care center

BACKGROUND

The mucocutaneous clinical profile of patients with amyloidosis in Latin America has been scarcely reported.

OBJECTIVE

To describe clinical characteristics of skin and mucosal manifestations in systemic amyloidosis in a tertiary care center in Mexico City.

METHODS

A cross sectional, retrospective analytical study was performed in patients with systemic amyloidosis over a 15-year period. Statistical analysis was done.

RESULTS

A total of 98 patients were included (53 [54%] men; overall median age = 49 years old). Acquired systemic immunoglobulin light chain amyloidosis (AL) was the most common (49%) type, followed by (24.5%) wild-type transthyretin amyloidosis (H-TTR) (24.5%), undetermined cases (21%), and reactive systemic amyloidosis (AA) (6.1%). There were mucocutaneous manifestations in 34.7% of cases, mostly multiple myeloma-related AL (ALMM). Head and neck was the most often affected site (38.2%), and purpuric macules were the most common morphology (44.1%). Mucocutaneous affectation was predominantly observed in AL (50.0%) compared to other types (20.0%) of amyloidosis (P = 0.01). Likewise, involvement of organs was also significantly different among the diverse amyloidosis types (P < 0.05). The most frequent comorbidities were hypertension (18.3%) and hypothyroidism (18.3%).

CONCLUSION

The clinical spectrum of manifestations in amyloidosis is wide. Involvement of skin and mucosa in amyloidosis is common; significant differences were observed concerning distribution of mucocutaneous amyloid manifestations among the different types of amyloidosis.

Epidemiology of AL amyloidosis: a real-world study using US claims data

Amyloid light-chain (AL) amyloidosis is a rare disease caused by extracellular deposition of misfolded immunoglobulin light chains. This study aimed to provide an up-to-date estimate of prevalence and incidence of AL amyloidosis in the United States. Using claims databases from years 2007 to 2015, adults ≥18 years old with AL amyloidosis were included if they had (1) at least 1 inpatient or 2 outpatient claims consistent with AL amyloidosis and (2) received 1 AL-specific treatment. Prevalence was calculated as the number of AL patients divided by the number of enrollees on June 30th of each calendar year. Incidence was calculated as the number of patients with AL who were disease-free and enrolled with a health plan for 1 year prior, divided by the number of enrollees with enrollment from July 1st of the previous year to June 30th of each calendar year. The prevalence of AL amyloidosis increased significantly between 2007 and 2015, from 15.5 cases per million in 2007 to 40.5 in 2015, an annual percentage change (APC) of 12% (P < .001). The incidence ranged from 9.7 to 14.0 cases per million person-years (APC, 3%; P = .114) with no statistically significant increase. There was an increase in AL amyloidosis prevalence over a 9-year period coupled with stable incidence rates. Although there is no diagnosis code specific to AL amyloidosis and no validated method for identifying this condition using claims data, extrapolating from our data, there are at least 12 000 adults in the United States living with AL amyloidosis, and the number seems likely to rise.

An Unusual Case of Acute Cholecystitis with Amyloidosis: A Case Report and Literature Review

We present an extremely rare case of amyloid A (AA) deposition in the gallbladder and review the literature on similar cases. The patient was a 76-year-old man who had been diagnosed with mild bronchiectasis three years previously, who was admitted to the hospital with right upper quadrant pain and fever. Computed tomography revealed swelling and wall thickening of the gallbladder with a small gallstone. The patient was diagnosed with acute cholecystitis and cholelithiasis and underwent open cholecystectomy. A postoperative histological examination revealed extensive AA deposition in the gallbladder wall. Thus, the definitive diagnosis was acute cholecystitis with AA amyloidosis.