Natural history and outcome in systemic AA amyloidosis

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.

Advancing Transthyretin Amyloidosis Drug Development in an Evolving Treatment Landscape: Amyloidosis Forum Meeting Proceedings

INTRODUCTION

Hereditary transthyretin amyloidosis (ATTRv, also referred to as hATTR; ORPHA 271861) and wild-type ATTR amyloidosis (ATTRwt; ORPHA 330001) are rare, progressive, systemic protein misfolding disorders with heterogeneous clinical presentations. ATTRv and ATTRwt amyloidosis are characterized by the deposition of amyloid fibrils in multiple organs including the heart, nerves, eyes, and soft tissues. The management of ATTR amyloidosis is complex because of its multisystemic nature and progression despite available treatment options. Morbidity is high and there are many unmet medical needs for patients. While contemporary ATTR amyloidosis cohorts are diagnosed earlier, have lower risk disease and lower mortality compared with the previous era, these advances coupled with the emergence of effective disease-modifying therapies have confounded the design of future prospective clinical trials and interpretation of historical control data.

MAIN BODY

The Amyloidosis Forum is a public-private partnership between the US Food and Drug Administration Center for Drug Evaluation and Research and the nonprofit Amyloidosis Research Consortium ( www.arci.org ). This article summarizes proceedings from the 21 June 2023 Amyloidosis Forum on advancing drug development in ATTR amyloidosis in an evolving treatment landscape. The Forum focused on elements of clinical trial design to address these challenges and discussed their strengths and weaknesses from multiple stakeholder perspectives (i.e., patient, sponsor, statistician, clinician, and regulatory authorities).

CONCLUSION

Given rapid evolution of natural history in ATTR amyloidosis, the utility of historical control data is limited. Leveraging contemporary real-world data is essential for clinical trial design. Evidence generation from clinical trials should address clinically relevant questions. Key factors in successful trial design must be informed by up-to-date data on natural history, prognostic factors, clinically meaningful thresholds, and sharing available clinical trial data. The Amyloidosis Forum includes the community of patients with ATTR amyloidosis, the physicians who treat them, and the sponsors and regulators who collectively stand ready to support further studies in order to develop novel effective therapies.

Gastrointestinal amyloidosis in a 50-year-old patient with miliary tuberculosis: A case report

This case highlights the importance of considering tuberculosis as an underlying cause of gastrointestinal amyloidosis, even in patients previously treated for the infection. Clinicians should maintain a high index of suspicion for atypical presentations of amyloidosis, especially in individuals with chronic inflammation, enabling early diagnosis and tailored management for improved patient outcomes.

Abstract

Gastrointestinal amyloidosis is a rare condition often associated with chronic inflammation. We present a unique case of a 50-year-old female with a history of miliary tuberculosis who developed gastrointestinal amyloidosis. The patient exhibited chronic loose stools, weight loss, abdominal pain, and urinary incontinence symptoms. Diagnostic workup revealed characteristic findings of amyloidosis on biopsy. Despite treatment for tuberculosis, her symptoms persisted, highlighting the challenging nature of managing this condition. This case underscores the importance of considering tuberculosis as a potential cause of secondary amyloidosis in patients with ongoing symptoms of inflammation and infection. Early recognition and tailored management are crucial in optimizing patient outcomes.

Development and Validation of Staging Systems for AA Amyloidosis

Key Points

Background

The kidney is involved in almost 100% of cases of AA amyloidosis, a rare disease caused by persistent inflammation with long overall survival but frequent progression to kidney failure. Identification of patients with advanced disease at diagnosis is difficult, given the absence of validated staging systems.

Methods

Patients with newly diagnosed AA amyloidosis from the Pavia (n=233, testing cohort) and Heidelberg (n=243, validation cohort) centers were included in this study. Cutoffs of continuous variables were determined by receiver operating characteristic analysis predicting death or dialysis at 24 months. Prognostic factors included in staging systems were identified by multivariable models in the testing cohort.

Results

Age ≥65 years, eGFR <45 ml/min per 1.73 m2, and elevated natriuretic peptides (type-B natriuretic peptide >130 ng/L and/or N-terminal type-B natriuretic peptide >1000 ng/L) were associated with overall survival and included in the staging system (all with simplified coefficients 1). Mean 36-month overall survival was lower with higher staging system scores (score 0–1: 92%; score 2: 72%; score 3: 32%). These results were confirmed in the validation cohort. For kidney failure, variables selected to enter in the staging system model were proteinuria >3 g/24 hour and eGFR <35 ml/min per 1.73 m2 (both with simplified coefficients 1). The 36-month cumulative incidence of kidney failure was higher with higher staging system scores (score 0: 0%; score 1: 24%; score 2: 51%). Again, similar results were obtained in validation cohort.

Conclusions

We identified and validated biomarker-based staging systems for overall survival and kidney failure in AA amyloidosis.

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.

Successful Pregnancy Outcome in a Patient with Juvenile Idiopathic Arthritis in Adulthood, Amyloid A Amyloidosis, and Chronic Kidney Disease Using Tocilizumab with Strict Blood Pressure Control

Pregnancies with chronic kidney disease (CKD) and high disease activity in rheumatic diseases are high-risk events with adverse outcomes for both the mother and fetus. We herein report a 35-year-old woman with juvenile idiopathic arthritis (JIA), amyloid A (AA) amyloidosis related to JIA, and CKD stage G4A2 who wished to have children. She achieved a successful pregnancy, even in the presence of these multiple risk factors, using tocilizumab to control the disease activity of JIA and AA amyloidosis, along with antihypertensive drugs to control her blood pressure before and during pregnancy.

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.

A case of AA amyloidosis complicated by proliferating pilomatricoma and a review of the literature

Although AA amyloidosis is primarily caused by inflammatory conditions, associations between AA amyloidosis and solid cancers have occasionally been described. Herein, we report the case of a 48-year-old man in whom resection of a proliferating pilomatricoma with deposition of AA amyloid resulted in remission of concomitant AA gastrointestinal amyloidosis. A rapidly growing, giant, reddish, ulcerated tumor measuring 16 × 13 cm in size was identified on the upper left arm on a visit to our hospital. Gastrointestinal AA amyloidosis was diagnosed from colorectal mucosal biopsy at the same time, and weight loss and profuse diarrhea were clinically evident. As treatment, the tumor was resected with a 10-mm surgical margin. Histologically, the tumor predominantly comprised a lobular proliferation of basophilic cells peripherally, filled with eosinophilic, cornified material and shadow cells with mitoses observed in basophilic cells. Specimens revealed eosinophilic, homogeneous deposits around tumor nests, which were confirmed as amyloid deposits by positive staining with Congo red stain. These deposits were immunohistochemically positive on staining with anti-serum amyloid A antibody. Collectively, proliferating pilomatricoma with AA amyloidosis was diagnosed. After tumor resection, chronic diarrhea resolved and no amyloid deposition was apparent in colorectal biopsy. It is important to remember that if amyloid deposition is present in a tumor, aggressive tumor excision may alleviate systemic amyloidosis.

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.

Systemic Amyloidosis and Kidney Transplantation: An Update

Amyloidosis is a heterogeneous disorder characterized by abnormal protein aggregate deposition that often leads to kidney involvement and end-stage kidney disease. With advancements in diagnostic techniques and treatment options, the prevalence of patients with amyloidosis requiring chronic dialysis has increased. Kidney transplantation is a promising avenue for extending survival and enhancing quality of life in these patients. However, the complex and heterogeneous nature of amyloidosis presents challenges in determining optimal referral timing for transplantation and managing post-transplantation course. This review focuses on recent developments and outcomes of kidney transplantation for amyloidosis-related end-stage kidney disease. This review also aims to guide clinical decision-making and improve management of patients with amyloidosis-associated kidney disease, offering insights into optimizing patient selection and post-transplant care for favorable outcomes.

Myocardial Calcification: An Unusual Complication of Remote Trauma With Coidentified Amyloidosis

We present the heart of a 38-year-old man with paraplegia due to a remote traumatic spinal cord injury. In the 20 years following his injury, he experienced chronic decubitus ulcers, osteomyelitis, neurogenic bladder, malnutrition, and urinary tract infections. He was admitted to the hospital with septic shock secondary to multiple decubitus ulcers and osteomyelitis and expired after a two-month hospitalization. At autopsy, there was marked replacement of left ventricle and interventricular septal myocardium by gritty, firm, yellow-white tissue. Microscopic examination demonstrated a remote infarct with marked dystrophic calcification and unexpected amyloid deposition. This example demonstrates the extraordinary extent to which dystrophic calcifications can replace myocardium and highlights multiple potential etiologies of myocardial calcifications. Of note, this is the first report documenting myocardial calcification as a complication of remote, non-iatrogenic trauma. The role of the amyloidosis in the development of calcification is unclear, but a contributory effect cannot be excluded.

Correlation of 99mTc-DPD bone scintigraphy with histological amyloid load in patients with ATTR cardiac amyloidosis

BACKGROUND

The significance of measuring 99mTc-labelled-3,3-diphosphono-1,2-propanodicarboxylic acid (99mTc-DPD) in transthyretin (ATTR) cardiac amyloidosis has not been adequately studied. This single-centre observational study evaluated the correlation between 99mTc-DPD scintigraphy and histological amyloid load in endomyocardial biopsy (EMB).

METHODS

Twenty-eight patients with biopsy-proven ATTR amyloidosis and concomitantly available 99mTc-DPD scintigraphy were included. Visual Perugini scoring, and (semi-)quantitative analysis of cardiac 99mTc-DPD uptake by planar whole-body imaging and single photon emission computed tomography (SPECT/CT) using regions of interest (ROI) were performed. From this, heart-to-whole-body ratio (H/WB) and heart-to-contralateral-chest ratio (H/CL) were calculated. The histological amyloid load was quantified using two different staining methods.

RESULTS

Increased cardiac tracer uptake was documented in all patients (planar: ROImean 129 ± 37 cps; SPECT/CT: ROImean 369 ± 142 cps). Histological amyloid load (19 ± 13%) significantly correlated with Perugini score (r = 0.69, p < .001) as well as with cardiac 99mTc-DPD uptake (planar: r = 0.64, p < .001; H/WB: r = 0.50, p = .014; SPECT/CT: r = 0.53, p = .008; H/CL: r = 0.43, p = .037) (results are shown for correlations with Congo Red-staining).

CONCLUSION

In ATTR, cardiac 99mTc-DPD uptake significantly correlated with histological amyloid load in EMB. Further studies are needed to implement thresholds in cardiac 99mTc-DPD uptake measurements for risk stratification and guidance of therapy.

Kidney Transplantation in Patients With AA Amyloidosis: Outcomes in a French Multicenter Cohort

RATIONALE & OBJECTIVE

Outcomes of kidney transplantation for patients with renal AA amyloidosis are uncertain, with reports of poor survival and high rates of disease recurrence. However, the data are inconclusive and mostly based on studies from the early 2000s and earlier.

STUDY DESIGN

Retrospective multicenter cohort study.

SETTING & PARTICIPANTS

We searched the French national transplant database to identify all patients with renal AA amyloidosis who underwent kidney transplantation between 2008 and 2018.

EXPOSURES

Age, cause of amyloidosis, use of biotherapies, and C-reactive protein levels.

OUTCOMES

Outcomes were all-cause mortality and allograft loss. We also reported amyloidosis allograft recurrence, occurrence of acute rejection episodes, as well as infectious, cardiovascular, and neoplastic disease events.

ANALYTICAL APPROACH

Kaplan-Meier estimator for mortality and cumulative incidence function method for allograft loss. Factors associated with patient and allograft survival were investigated using a Cox proportional hazards model and a cause-specific hazards model, respectively.

RESULTS

86 patients who received kidney transplants for AA amyloidosis at 26 French centers were included. The median age was 49.4 years (IQR, 39.7-61.1). The main cause of amyloidosis was familial Mediterranean fever (37 cases; 43%). 16 (18.6%) patients received biotherapy after transplantation. Patient survival rates were 94.0% (95% CI, 89.1-99.2) at 1 year and 85.5% (77.8-94.0) at 5 years after transplantation. Cumulative incidences of allograft loss were 10.5% (4.0-17.0) at 1 year and 13.0% (5.8-20.1) at 5 years after transplantation. Histologically proven AA amyloidosis recurrence occurred in 5 transplants (5.8%). An infection requiring hospitalization developed in 55.8% of cases, and there was a 27.9% incidence of acute allograft rejection. Multivariable analysis showed that C-reactive protein concentration at the time of transplantation was associated with patient survival (HR, 1.01; 95% CI, 1.00-1.02; P=0.01) and allograft survival (HR, 1.68; 95% CI, 1.10-2.57; P=0.02).

LIMITATIONS

The study lacked a control group, and the effect of biotherapies on transplantation outcomes could not be explored.

CONCLUSIONS

This relatively contemporary cohort of patients who received a kidney transplant for AA amyloidosis experienced favorable rates of survival and lower recurrence rates than previously reported. These data support the practice of treating these patients with kidney transplantation for end-stage kidney disease.

PLAIN-LANGUAGE SUMMARY

AA amyloidosis is a severe and rare disease. Kidney involvement is frequent and leads to end-stage kidney disease. Because of the involvement of other organs, these patients are often frail, which has raised concerns about their suitability for kidney transplantation. We reviewed all patients with AA amyloidosis nephropathy who underwent kidney transplantation in France in the recent era (2008-2018) and found that the outcomes after kidney transplantation were favorable, with 85.5% of patients still alive 5 years after transplantation, a survival rate that is comparable to the outcomes of patients receiving a transplant for other forms of kidney diseases. Recurrence of amyloidosis in the transplanted kidney was infrequent (5.8%). These data support the practice of kidney transplantation for patients with AA amyloidosis who experience kidney failure.

Systemic Amyloid A Amyloidosis Secondary to Xanthogranulomatous Pyelonephritis

The combination of systemic amyloid A (AA) amyloidosis and xanthogranulomatous pyelonephritis (XGP) resulting from a chronic urinary tract infection is extremely rare. We herein report a case of systemic AA amyloidosis secondary to XGP for which clinical remission developed after nephrectomy. To our knowledge, this is the first case report describing the clinical improvement of systemic AA amyloidosis secondary to XGP after nephrectomy in Japan. Clinicians should be aware of this uncommon combination and search for amyloid depositions in cases of XGP.

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.

Anakinra-Associated Systemic Amyloidosis

OBJECTIVE

To describe a 41-year-old woman with a history of neonatal onset multisystem inflammatory disease, on treatment with daily subcutaneous injections of 600 mg of recombinant interleukin-1 receptor antagonist (IL-1Ra) protein, anakinra, since the age of 28, who presented with golf-ball size nodules at the anakinra injection sites, early satiety, new onset nephrotic syndrome in the context of normal markers of systemic inflammation.

METHODS

Clinical history and histologic evaluation of biopsies of skin, gastric mucosa, and kidney with Congo-red staining and proteomic evaluation of microdissected Congo red-positive amyloid deposits by liquid chromatography-tandem mass spectrometry.

RESULTS

The skin, stomach, and kidney biopsies all showed the presence of Congo red-positive amyloid deposits. Mass spectrometry-based proteomics demonstrated that the amyloid deposits in all sites were of AIL1RAP (IL-1Ra protein)-type. These were characterized by high spectral counts of the amyloid signature proteins (apolipoprotein AIV, apolipoprotein E, and serum amyloid P-component) and the amyloidogenic IL-1Ra protein, which were present in Congo red-positive areas and absent in Congo red-negative areas. The amino acid sequence identified by mass spectrometry confirmed that the amyloid precursor protein was recombinant IL-1Ra (anakinra) and not endogenous wild-type IL-1Ra.

CONCLUSION

This is the first report of iatrogenic systemic amyloidosis due to an injectable protein drug, which was caused by recombinant IL1Ra (anakinra).

Ankylosing spondylitis status and risk of secondary systemic amyloidosis: A two-sample mendelian randomization study

OBJECTIVES

There is still controversy regarding the causal relationship between ankylosing spondylitis (AS) and secondary systemic amyloidosis (SSA). This study utilized aggregated data from genome-wide association studies (GWAS) on population cohorts to investigate whether a causal relationship exists between AS and SSA.

METHODS

The genetic causal relationship between AS status and SSA was analyzed utilizing a two-sample Mendelian randomization (TSMR). The analyses were conducted using the weighted mode method (WM2), inverse variance weighted method (IVW), simple mode (SM), weighted median method (WM1), and Mendelian randomization Egger regression (MR-Egger). Among these methods, the primary results were based on the IVW approach. The association was evaluated using the odds ratio (OR) along with a 95% confidence interval (95% CI).

RESULTS

The IVW analysis revealed a positive causal relationship between AS status and SSA (OR = 1.411, 95 % CI = 1.069, 1.862, P = 0.015). Meanwhile, the WM1 (OR = 1.394, 95 % CI = 1.115, 1.742, P = 0.004) and WM2 (OR = 1.393, 95 % CI = 1.112, 1.743, P = 0.045) methods also identified a positive causal relationship between AS status and SSA. The MR-Egger method did not identify a causal relationship between AS and SSA (OR = 1.175, 95 % CI = 0.888, 1.555, P = 0.342). The SM results demonstrated that the observed genotypes did not exhibit statistically significant differences between AS and SSA (OR = 1.184, 95 % CI = 0.416, 3.366, P = 0.767). The results of the MR-Egger regression suggested that the results were unaffected by bias caused by genetic pleiotropy (Intercept = 0.283, SE = 0.134, P = 0.126). Cochran's Q test did not reveal any significant heterogeneity (Q = 1.759, P = 0.624). The "leave-one-out" analysis further confirmed that the absence of any single SNP did not impact the robustness of our results.

CONCLUSION

This study revealed a positive causal relationship between AS status and the occurrence of SSA, providing new insights into the genetic analysis of SSA.

Investigation of serum amyloid a within animal species focusing on the 1-25 amino acid region

AA amyloidosis, characterized by the misfolding of serum amyloid A (SAA) protein, is the most common amyloid protein disorder across multiple species. SAA is a positive-acute phase protein synthesized by the liver in response to inflammation or stress, and it normally associates with high-density lipoprotein at its N-terminus. In this study, we focused on the 1-25 amino acid (aa) region of the complete 104 aa SAA sequence to examine the aggregation propensity of AA amyloid. A library comprising eight peptides from different species was assembled for analysis. To access the aggregation propensity of each peptide region, a bioinformatic study was conducted using the algorithm TANGO. Congo red (CR) binding assays, Thioflavin T (ThT) assays, and transmission electron microscopy (TEM) were utilized to evaluate whether the synthesized peptides formed amyloid-like fibrils. All synthetic SAA 1-25 congeners resulted in amyloid-like fibrils formation (per CR and/or ThT staining and TEM detection) at the exception of the ferret SAA1-25 fragment, which generated plaque-like materials by TEM. Ten residues were preserved among SAA 1-25 congeners resulting in amyloid-like fibrils, i.e. F6, E9, A10, G13, D16, M17, A20, Y21, D23, and M24. Amino acid residues highlighted by this study may have a role in increasing the propensity for amyloid-like fibril formation. This study put an emphasis on region 1-25 in the mechanism of SAA1 misfolding.

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.

Post COVID-19 AA amyloidosis of the kidneys with rapidly progressive renal failure

Coronavirus disease 2019 (COVID-19) pandemic has taken the world by a storm, posing a gruelling challenge to the medical fraternity globally. Besides its very high infectivityinfectivity, significant organ dysfunction occurs in critically ill COVID-19 patients, leading to severe morbidity and mortality. Pulmonary involvement is the leading cause of death in these patients to be followed by the cardiovascular involvement. Kidney involvement due to COVID-19 is becoming more discernible with AKI adversely affecting the outcome. Besides AKI, a few cases of collapsing FSGS in genetically vulnerable patients and thrombotic microangiopathies have been reported as well. We report a case of AA amyloidosis of the kidney with a rapidly progressive renal failure and congestive heart failure with preserved left ventricular functions, which complicated a moderate COVID-19 pneumonia providing some clues to a possible association of this novel virus disease with this complication, which needs to be confirmed in future studies.

The spectrum of pulmonary amyloidosis

Amyloidosis is a disease caused by misfolded proteins that deposit in the extracellular matrix as fibrils, resulting in the dysfunction of the involved organ. The lung is a common target of Amyloidosis, but pulmonary amyloidosis is uncommonly diagnosed since it is rarely symptomatic. Diagnosis of pulmonary amyloidosis is usually made in the setting of systemic amyloidosis, however in cases of localized pulmonary disease, surgical or transbronchial tissue biopsy might be indicated. Pulmonary amyloidosis can be present in a variety of discrete entities. Diffuse Alveolar septal amyloidosis is the most common type and is usually associated with systemic AL amyloidosis. Depending on the degree of the interstitial involvement, it may affect alveolar gas exchange and cause respiratory symptoms. Localized pulmonary Amyloidosis can present as Nodular, Cystic or Tracheobronchial Amyloidosis which may cause symptoms of airway obstruction and large airway stenosis. Pleural effusions, mediastinal lymphadenopathy and pulmonary hypertension has also been reported. Treatment of all types of pulmonary amyloidosis depends on the type of precursor protein, organ involvement and distribution of the disease. Most of the cases are asymptomatic and require only close monitoring. Diffuse alveolar septal amyloidosis treatment follows the treatment of underlying systemic amyloidosis. Tracheobronchial amyloidosis is usually treated with bronchoscopic interventions including debulking and stenting or with external beam radiation. Long-term prognosis of pulmonary amyloidosis usually depends on the type of lung involvement and other organ function.

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.

Patisiran Treatment in Patients with Transthyretin Cardiac Amyloidosis

BACKGROUND

Transthyretin amyloidosis, also called ATTR amyloidosis, is associated with accumulation of ATTR amyloid deposits in the heart and commonly manifests as progressive cardiomyopathy. Patisiran, an RNA interference therapeutic agent, inhibits the production of hepatic transthyretin.

METHODS

In this phase 3, double-blind, randomized trial, we assigned patients with hereditary, also known as variant, or wild-type ATTR cardiac amyloidosis, in a 1:1 ratio, to receive patisiran (0.3 mg per kilogram of body weight) or placebo once every 3 weeks for 12 months. A hierarchical procedure was used to test the primary and three secondary end points. The primary end point was the change from baseline in the distance covered on the 6-minute walk test at 12 months. The first secondary end point was the change from baseline to month 12 in the Kansas City Cardiomyopathy Questionnaire-Overall Summary (KCCQ-OS) score (with higher scores indicating better health status). The second secondary end point was a composite of death from any cause, cardiovascular events, and change from baseline in the 6-minute walk test distance over 12 months. The third secondary end point was a composite of death from any cause, hospitalizations for any cause, and urgent heart failure visits over 12 months.

RESULTS

A total of 360 patients were randomly assigned to receive patisiran (181 patients) or placebo (179 patients). At month 12, the decline in the 6-minute walk distance was lower in the patisiran group than in the placebo group (Hodges-Lehmann estimate of median difference, 14.69 m; 95% confidence interval [CI], 0.69 to 28.69; P = 0.02); the KCCQ-OS score increased in the patisiran group and declined in the placebo group (least-squares mean difference, 3.7 points; 95% CI, 0.2 to 7.2; P = 0.04). Significant benefits were not observed for the second secondary end point. Infusion-related reactions, arthralgia, and muscle spasms occurred more often among patients in the patisiran group than among those in the placebo group.

CONCLUSIONS

In this trial, administration of patisiran over a period of 12 months resulted in preserved functional capacity in patients with ATTR cardiac amyloidosis. (Funded by Alnylam Pharmaceuticals; APOLLO-B ClinicalTrials.gov number, NCT03997383.).

Treat-to-target strategies for the management of familial Mediterranean Fever in children

BACKGROUND

The objective of this initiative was to develop a treat-to-target (T2T) approach for the management of patients with Familial Mediterranean Fever (FMF), including the definition of a complex treatment target, and establish strategies that improve patient care and long-term outcome.

METHODS

An initial set of statements as well as a flow chart visualising the proposed concept was developed. To adapt the preliminary statements to the current state of knowledge, a systematic literature search was performed and the modified statements were subject to a Delphi approach. To ensure the applicability of the statements in daily practice, an online survey was conducted among paediatric rheumatologists in Germany. In addition, data from the national AID-NET registry were analysed with respect to therapeutic response.

RESULTS

This T2T initiative yielded a total of 26 statements guiding FMF management with respect to diagnosis, treatment targets, treatment strategies and monitoring. The online survey identified cut-off values for inflammatory markers indicating treatment intensification and appropriate measures in case of colchicine intolerance or non-adherence. The analysis of data derived from the national AID-NET showed that colchicine therapy was successfully terminated in 61% of patients (27 out of 44) with heterozygous MEFV mutations. Multidimensional treatment targets incorporating objective and subjective reported outcome measures were developed. These provide the basis for stratifying patients into the following treatment paths: continue colchicine, persisting attacks / inflammation, colchicine intolerance, persisting arthritis, colchicine reduction and adjustment/reduction of biologics.

CONCLUSIONS

The proposed consensus treatment plan for the management of FMF incorporates multidimensional targets allowing transparent treatment decisions, which will promote personalised disease management and increase adherence to therapy.

Unicentric Castleman's disease associated with malignant cardiac Amyloid-A amyloidosis: a case report

Background

Unicentric Castleman's disease (UCD), a lymphoproliferative disorder characterized by enlargement of the lymph nodes, is a rare cause of Amyloid-A amyloidosis. While patients usually present with impaired kidney function and proteinuria, heart involvement is neither common nor the main cause of signs and symptoms.

Case summary

We present a patient who was admitted to the hospital for impaired exercise capacity. Diagnostic work-up revealed severe left ventricular hypertrophy suggestive of cardiac amyloidosis. Although Congo red staining of endomyocardial biopsies was initially negative, subsequent immunohistochemical staining against serum amyloid A finally confirmed the diagnosis of cardiac amyloidosis. 18F-fluorodeoxyglucose positron emission tomography/computed tomography revealed a tumour located in dorsal of the duodenum. Fine-needle aspiration biopsy of the tumour was suggestive but could not confirm the presence of UCD beyond reasonable doubt. Rapid worsening of heart failure symptoms warranted urgent surgical tumourectomy, which resulted in immediate post-operative lowering of serum amyloid protein. However, post-operative cardiogenic shock could not be stabilized even with veno-arterial extracorporeal membrane oxygenation, and the patient eventually died. The UCD of the hyaline vascular (HV) subtype was confirmed by pathologic work-up of the excised tumour.

Discussion

This case report presents for the first time a patient with malignant cardiac Amyloid-A amyloidosis caused by unicentric Castleman's disease of the HV subtype. Since the disease progresses swiftly, rapid diagnosis is essential for potential curative treatment.

Comparison of posterior segment ocular parameters of Familial mediterranean fever with homozygous M694V mutation and carriers with heterozygous M694V mutation in children

PURPOSE

The aim of this study is to comparatively evaluate the posterior segment ocular parameters of Familial Mediterranean fever (FMF) patients, asymptomatic FMF carriers, and the healthy controls in the pediatric age group.

METHODS

The study included 30 FMF patients with homozygous M694V mutation in remission under colchicine therapy, 12 asymptomatic FMF carriers with heterozygous M694V mutation, and 41 age-sex-matched healthy controls. All patients underwent detailed eye examination, and peripapillary retinal nerve fiber layer (pRNFL) thickness, central macular thickness (CMT), subfoveal choroidal thickness (SCT), macular vascular densities, and foveal avascular zone (FAZ) areas were measured using swept-source optical coherence tomography angiography.

RESULTS

In this study, the mean pRNFL thickness was statistically significantly thinner (p = 0.010) in the FMF patients group compared to the FMF carriers group and the healthy control group, especially in the inferior quadrant of pRNFL (p = 0.042). The CMT in asymptomatic FMF carriers group was statistically significantly thicker than in FMF patients group (p = 0.037), especially the superior and inferior quadrants of macula were affected (p = 0.024; p = 0.020, respectively). In addition, this study showed that the changes of pRNFL thickness and CMT in pediatric patients with FMF were moderately correlated with the duration of diagnosis. There was no significant difference between the groups in terms of macular vascular densities and FAZ values.

CONCLUSION

FMF is a hereditary autoinflammatory disease that causes multi-organ involvement, and this study showed that posterior segment ocular parameters could be affected not only in FMF patients but also in asymptomatic FMF carriers.

Diagnostic Efficacy of Renal 2-D Shear Wave Elastography in Familial Mediterranean Fever Disease

ABSTRACT

The aims of this study were to evaluate the kidneys of patients with familial Mediterranean fever (FMF) noninvasively and quantitatively using 2-D shear wave elastography (SWE) and to reveal the diagnostic efficacy of SWE in FMF-induced renal involvement. Healthy controls, FMF patients, and FMF patients with proteinuria were included in the study, and differences in renal stiffness values between the groups were examined. In addition, a relationship between age, sex, height, weight, body mass index, serum erythrocyte sedimentation rate, C-reactive protein, glomerular filtration rate, and renal stiffness values was evaluated. A total of 120 subjects, including 60 controls, 41 FMF patients without proteinuria, and 19 FMF patients with proteinuria, were enrolled in the study. Renal stiffness values were found to be significantly higher in the group with FMF compared with the control group. In addition, the values in the proteinuria group were higher than both the control group and FMF patients without proteinuria ( P < 0.001). A significant positive correlation was found between the renal stiffness value and C-reactive protein. According to receiver operating characteristic analysis, the mean renal stiffness value was 7.905 kPa or greater to determine FMF-induced proteinuria. The current study shows that renal stiffness values were higher in FMF patients compared with the normal population and the values showed further increase in the presence of proteinuria, which indicates a more advanced stage of renal involvement of the disease. These findings reveal that SWE can be used as a noninvasive diagnostic tool in the diagnosis, follow-up, and evaluating the severity of FMF.

Pathological spectrum of hereditary transthyretin renal amyloidosis and clinicopathologic correlation: a French observational study

BACKGROUND

Cardiac and neurological involvements are the main clinical features of hereditary transthyretin (ATTRv) amyloidosis. Few data are available about ATTRv amyloid nephropathy (ATTRvN).

METHODS

We retrospectively included 30 patients with biopsy-proven ATTRvN [V30M (26/30) including two domino liver recipients, S77Y (2/30), V122I (1/30) and S50R (1/30) variants] from two French reference centers. We described the pathological features by comparing amyloid deposits distribution to patients with AL or AA amyloidosis, and sought to determine clinicopathological correlation with known disease-modifying factors such as TTR variant, gender and age at diagnosis.

RESULTS

In comparison with AL and AA amyloidosis, ATTRv patients had similar glomerular, arteriolar and arterial amyloid deposits, but more cortical and medullary tubulointerstitial (33%, 44%, 77%, P = .03) involvement. While the presence of glomerular deposits is associated with the range of proteinuria, some patients with abundant glomerular ATTRv amyloidosis had no significant proteinuria. V30M patients had more glomerular (100% and 25%, odds ratio = 114, 95% confidence interval 3.85-3395.00, P = .001) deposits, and higher estimated glomerular filtration rate [50 (interquartile range 44-82) and 27 (interquartile range 6-31) mL/min/1.73 m², P = .004] than non-V30M patients. We did not find difference in amyloid deposition according to gender or age at diagnosis.

CONCLUSION

ATTRvN affects all kidney compartments, but compared with AL/AA amyloidosis, ATTRvN seems to involve more frequently tubulointerstitial areas. V30M patients represents the dominant face of the disease with a higher risk of glomerular/arteriolar involvement. ATTRvN should thus be considered in patients, and potential relatives, with ATTRv amyloidosis and kidney dysfunction, regardless of proteinuria level.

Vector autoregression: Useful in rare diseases?-Predicting organ response patterns in a rare case of secondary AA amyloidosis

BACKGROUND

Statistical analyses of clinical data are a cornerstone in understanding pathomechanisms of disorders. In rare disorders, cross-sectional datasets of sufficient size are usually not available. Taking AA amyloidosis as an example of a life-threatening rare disorder resulting from of uncontrolled chronic inflammation, we propose techniques from time series analysis to predict organ response to treatment. The advantage of time-series analysis is that it solely relies on temporal variation and therefore allows analyzing organ response to treatment even when the cross-sectional dimension is small.

METHODS

The joint temporal interdependence of inflammatory activity and organ response was modelled multivariately using vector autoregression (VAR) based on a unique 4.5 year spanning data set of routine laboratory, imaging data (e.g., 18F-Florbetaben-PET/CT) and functional investigations of a 68-year-old patient with multi-organ involvement of AA amyloidosis due to ongoing inflammatory activity of a malignant paraganglioma in stable disease for >20 years and excellent response to tocilizumab).

RESULTS

VAR analysis showed that alterations in inflammatory activity forecasted alkaline phosphatase (AP). AP levels, but not inflammatory activity at the previous measurement time point predicted proteinuria.

CONCLUSION

We demonstrate the feasibility and value of time series analysis for obtaining clinically reliable information when the rarity of a disease prevents conventional prognostic modelling approaches. We illustrate the comparative utility of blood, functional and imaging markers to monitor the development and regression of AA amyloidosis.

Autoinflammatory diseases and the kidney

The kidney represents an important target of systemic inflammation. Its involvement in monogenic and multifactorial autoinflammatory diseases (AIDs) vary from peculiar and relatively frequent manifestations to some rare but severe features that may end up requiring transplantation. The pathogenetic background is also very heterogeneous ranging from amyloidosis to non-amyloid related damage rooted in inflammasome activation. Kidney involvement in monogenic and polygenic AIDs may present as renal amyloidosis, IgA nephropathy, and more rarely as various forms of glomerulonephritis (GN), namely segmental glomerulosclerosis, collapsing glomerulopathy, fibrillar, or membranoproliferative GN. Vascular disorders such as thrombosis or renal aneurysms and pseudoaneurysms may be encountered in patients with Behcet's disease. Patients with AIDs should be routinely assessed for renal involvement. Screening with urinalysis, serum creatinine, 24-h urinary protein, microhematuria, and imaging studies should be carried out for early diagnosis. Awareness of drug-induced nephrotoxicity, drug-drug interactions as well as addressing the issue of proper renal adjustment of drug doses deserve a special mention and should always be considered when dealing with patients affected by AIDs. Finally, we will explore the role of IL-1 inhibitors in AIDs patients with renal involvement. Targeting IL-1 may indeed have the potential to successfully manage kidney disease and improve long-term prognosis of AIDs patients.

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.

Patisiran for the Treatment of Transthyretin-mediated Amyloidosis with Cardiomyopathy

Transthyretin (TTR) is a tetrameric protein, synthesized primarily by the liver, that acts as a physiological transport protein for retinol and thyroxine. TTR can misfold into pathogenic amyloid fibrils that deposit in the heart and nerves, causing a life-threatening transthyretin amyloidosis cardiomyopathy (ATTR-CM), and a progressive and debilitating polyneuropathy (ATTR-PN). Recent therapeutic advances have resulted in the development of drugs that reduce TTR production. Patisiran is a small interfering RNA that disrupts the complimentary mRNA and inhibits TTR synthesis, and is the first gene-silencing medication licensed for the treatment of ATTR amyloidosis. After encouraging results following the use of patisiran for the treatment of patients with ATTR-PN, there has been increasing interest in the use of patisiran for the treatment of ATTR-CM. Various studies have demonstrated improvements across a wide range of cardiac biomarkers following treatment with patisiran, and have changed the perception of ATTR-CM from being thought of as a terminal disease process, to now being regarded as a treatable disease. These successes represent a huge milestone and have the potential to revolutionize the landscape of treatment for ATTR-CM. However, the long-term safety of patisiran and how best to monitor cardiac response to treatment remain to be determined.

Amyloidosis and the Kidney: An Update

Various types of systemic amyloidosis can wreak havoc on the architecture and functioning of the kidneys. Amyloidosis should be suspected in patients with worsening kidney function, proteinuria, and multisystem involvement, but isolated kidney involvement also is possible. Confirming the amyloidosis type and specific organ dysfunction is of paramount importance to select the appropriately tailored treatment and aim for better survival while avoiding treatment-associated toxicities. Amyloid renal staging in light chain amyloidosis amyloidosis helps inform prognosis and risk for end-stage kidney disease. Biomarker-based staging systems and response assessment guide the therapeutic strategy and allow the timely identification of refractory or relapsing disease so that patients can be switched to salvage therapy. Kidney transplantation is a viable option for selected patients with amyloidosis. Because of the complex nature of the pathophysiology and treatment of amyloidosis, a multidisciplinary team-based approach should be used in the care of these patients.

Renal involvement in monogenic autoinflammatory diseases: A narrative review

Autoinflammatory diseases (AIDs) are mostly caused by dysfunctions in single genes encoding for proteins with a prominent role in the regulation of innate immunity, such as complement factors, inflammasome components, tumour necrosis factor (TNF)-α, and proteins belonging to type I-interferon (IFN) signalling pathways. Due to the deposition of amyloid A (AA) fibrils in the glomeruli, unprovoked inflammation in AIDs frequently affects renal health. In fact, secondary AA amyloidosis is the most common form of amyloidosis in children. It is caused by the extracellular deposition of fibrillar low-molecular weight protein subunits resulting from the degradation and accumulation of serum amyloid A (SAA) in numerous tissues and organs, primarily the kidneys. The molecular mechanisms underlying AA amyloidosis in AIDs are the elevated levels of SAA, produced by the liver in response to pro-inflammatory cytokines, and a genetic predisposition due to specific SAA isoforms. Despite the prevalence of amyloid kidney disease, non-amyloid kidney diseases may also be responsible for chronic renal damage in children with AIDs, albeit with distinct characteristics. Glomerular damage can result in various forms of glomerulonephritis with distinct histologic characteristics and a different underlying pathophysiology. This review aims to describe the potential renal implications in patients with inflammasomopathies, type-I interferonopathies, and other rare AIDs in an effort to improve the clinical course and quality of life in paediatric patients with renal involvement.

Hepatic Manifestations of Systemic Diseases

In addition to being the primary target of infections such as viral hepatitis, the liver may also be affected by systemic disease. These include bacterial, mycotic, and viral infections, as well as autoimmune and infiltrative diseases. These conditions generally manifest as abnormal liver biochemistries, often with a cholestatic profile, and may present with additional signs/symptoms such as jaundice and fever. A high index of suspicion and familiarity with potential causal entities is necessary to guide appropriate testing, diagnosis, and treatment.

Current Status of Radionuclide Imaging of Transthyretin Cardiac Amyloidosis

Cardiac single photon emission computed tomography using 99mTc-bone avid tracers allows for an accurate noninvasive diagnosis of transthyretin (ATTR) cardiac amyloidosis, a historically underdiagnosed disease. This imaging is recommended in select populations who demonstrate clinical and imaging features of infiltrative cardiomyopathy. It is imperative to concomitantly assess for light chain (AL) cardiac amyloidosis independent of radionuclide scintigraphy for timely management of AL amyloidosis, a deadly disease requiring urgent therapy. Clinical judgement is also key and in some select scenarios an endomyocardial biopsy may be needed even after a noninvasive evaluation.

Inflammation across the spectrum of hypertrophic cardiac phenotypes

The hypertrophic cardiomyopathy phenotype encompasses a heterogeneous spectrum of genetic and acquired diseases characterized by the presence of left ventricular hypertrophy in the absence of abnormal cardiac loading conditions. This "umbrella diagnosis" includes the "classic" hypertrophic cardiomyopathy (HCM), due to sarcomere protein gene mutations, and its phenocopies caused by intra- or extracellular deposits, such as Fabry disease (FD) and cardiac amyloidosis (CA). All these conditions share a wide phenotypic variability which results from the combination of genetic and environmental factors and whose pathogenic mediators are poorly understood so far. Accumulating evidence suggests that inflammation plays a critical role in a broad spectrum of cardiovascular conditions, including cardiomyopathies. Indeed, inflammation can trigger molecular pathways which contribute to cardiomyocyte hypertrophy and dysfunction, extracellular matrix accumulation, and microvascular dysfunction. Growing evidence suggests that systemic inflammation is a possible key pathophysiologic process potentially involved in the pathogenesis of cardiac disease progression, influencing the severity of the phenotype and clinical outcome, including heart failure. In this review, we summarize current knowledge regarding the prevalence, clinical significance, and potential therapeutic implications of inflammation in HCM and two of its most important phenocopies, FD and CA.

Natural course and determinants of short-term kidney function decline in hereditary transthyretin amyloidosis: a French observational study

Data regarding renal involvement in patients with hereditary transthyretin (ATTRv) amyloidosis are scarce and the natural course of chronic kidney disease (CKD) in this population remains unclear. This observational study, including adult patients diagnosed with ATTRv amyloidosis at the French Reference Centre for Cardiac Amyloidosis, investigated renal function outcome and its determinants. Multivariable logistic regression models identified factors associated with CKD at baseline. Determinants of the change in estimated glomerular filtration rate (eGFR) over 24 months of follow-up were assessed with a multivariable linear mixed-effects model. In total, 232 patients (78 women [34%], mean age: 64 years) with ATTRv amyloidosis were classified on the basis of their TTR variants: ATTRV122I (37%), ATTRV30M (29%), and other variants (34%). Median baseline eGFR was 78 ml/min/1.73 m². Seventy-two patients (31%) had an eGFR below 60 ml/min/1.73m² and 27/137 patients (20%) had significant proteinuria (urine protein/creatinine ratio ≥30 mg/mmol). Renal biopsy, performed in four cases, found typical Congo red-positive and TTR-labelled amyloid deposits in all cases. Older age (OR 1.07, p < .001) and a prior history of hypertension (OR 2.09, p = .04) were associated with a higher prevalence of CKD at baseline, whereas higher left ventricular global longitudinal strain (LVGLS) (OR 0.83, p < .001) was associated with a lower prevalence. The estimated change in eGFR was -7.12 [-9.61, -4.63] and -8.21 [-10.81, -5.60] ml/min/1.73 m² after 12 and 24 months of follow-up, respectively. eGFR decline was independently associated with older age ((67-74], coefficient= -14.35 mL/min/1.73 m², p < .01, >74, coefficient = -22.93 mL/min/1.73 m², p < .001, versus <56), ATTRV122I (coefficient = -17.17 mL/min/1.73m², p < .01, versus ATTRV30M) and LVGLS (coefficient = 1.22, p < .01). These data suggest that CKD is a common finding in patients with ATTRv amyloidosis, and that eGFR decline is rapid during the first year of evaluation. Older age, lower LVGLS and ATTRV122I were associated with a worse renal outcome. Further studies are now needed to evaluate effects of new targeted therapies on long term renal function.

Renal AA amyloidosis: presentation, diagnosis, and current therapeutic options: a review

Amyloid A amyloidosis is thought to be the second most common form of systemic amyloidosis behind amyloidosis secondary to monoclonal Ig. It is the result of deposition of insoluble fibrils in the extracellular space of tissues and organs derived from the precursor protein serum amyloid A, an acute phase reactant synthesized excessively in the setting of chronic inflammation. The kidney is the most frequent organ involved. Most patients present with proteinuria and kidney failure. The diagnosis is made through tissue biopsy with involvement of the glomeruli in most cases, but also often of the vessels and the tubulointerstitial compartment. The treatment usually targets the underlying etiology and consists increasingly of blocking the inflammatory cascade of cytokines with interleukin-1 inhibitors, interleukin-6 inhibitors, and tumor necrosis factor-α inhibitors to reduce serum amyloid A protein formation. This strategy has also shown efficacy in cases where an underlying etiology cannot be readily identified and has significantly improved the prognosis of this entity. In addition, there has been increased interest at developing effective therapies able to clear amyloid deposits from tissues, albeit with mitigated results so far.

Amyloid A amyloidosis on medullary sponge kidney in a 28-year-old male with gout: A case report and literature review

Amyloidosis is a large group of diseases that occur through misfolding of extracellular proteins that accumulate in tissues and organs. Gout is the most common inflammatory arthritis worldwide and starts with the crystallization of uric acid within the joints and soft tissues. Although gouty arthritis is accompanied by inflammation, AA amyloidosis is rarely seen in patients with gout. Here we present a case of AA amyloidosis on the medullary sponge kidney in a 28-year-old man with gout. Our case had been diagnosed with gout 3 years previously, and his older brother was also diagnosed with early-onset gout. As a result of the hyperuricemic nephropathy clinic and familial history, a whole gene sequence analysis was performed on the HPRT1 gene and UMOD gene, but no pathogenic changes were detected. Renal ultrasound revealed a bilateral medullary sponge kidney and amyloidosis was detected in the renal needle biopsy performed for the etiology of proteinuria. In our literature review, we found 16 cases in which gout was accompanied by AA amyloidosis. We present a 17th case and compare it with the other 16 cases.

French practical guidelines for the diagnosis and management of AA amyloidosis

AA amyloidosis is secondary to the deposit of excess insoluble Serum Amyloid A (SAA) protein fibrils. AA amyloidosis complicates chronic inflammatory diseases, especially chronic inflammatory rheumatisms such as rheumatoid arthritis and spondyloarthritis; chronic infections such as tuberculosis, bronchectasia, chronic inflammatory bowel diseases such as Crohn's disease; and auto-inflammatory diseases including familial Mediterranean fever. This work consists of the French guidelines for the diagnosis workup and treatment of AA amyloidosis. We estimate in France between 500 and 700 cases in the whole French population, affecting both men and women. The most frequent organ impaired is kidney which usually manifests by oedemas of the lower extremities, proteinuria, and/or renal failure. Patients are usually tired and can display digestive features anf thyroid goiter. The diagnosis of AA amyloidosis is based on detection of amyloid deposits on a biopsy using Congo Red staining with a characteristic green birefringence in polarized light. Immunohistochemical analysis with an antibody directed against Serum Amyloid A protein is essential to confirm the diagnosis of AA amyloidosis. Peripheral inflammatory biomarkers can be measured such as C Reactive protein and SAA. We propose an algorithm to guide the etiological diagnosis of AA amyloidosis. The treatement relies on the etiologic treatment of the undelying chronic inflammatory disease to decrease and/or normalize Serum Amyloid A protein concentration in order to stabilize amyloidosis. In case of renal failure, dialysis or even a kidney transplant can be porposed. Nowadays, there is currently no specific treatment for AA amyloidosis deposits which constitutes a therapeutic challenge for the future.

Long-term results of kidney transplantation in patients with familial mediterranean fever

INTRODUCTION

Long-term kidney transplantation (KT) results in patients with familial Mediterranean fever (FMF)-related amyloidosis are not well studied. This study reviewed the long-term survival outcomes of FMF patients who underwent KT.

METHODS

We compared the outcomes of 31 patients who underwent (KT) for biopsy-proven amyloidosis secondary to FMF with 31 control patients (five with diabetes mellitus and 26 with nondiabetic kidney disease) undergoing KT between 1994 and 2021 at Başkent University Hospital. All data were recorded retrospectively from patients' files.

RESULTS

THE MEDIAN AGE (QUARTILE DEVIATION: QD) at the time of KT in the FMF and control group were 31 (6.7) and 33 (11), respectively. The median follow-up period (QD) after KT was 108 (57) months in the FMF and 132 (72) months in the control group. In the FMF group, graft and patient survivals were 71% and 84% at 5 years and 45% and 48% at 10 years, respectively. In the control group, graft and patient survivals were 79% and 100% at 5 years and 63% and 71% at 10 years, respectively. Patient survival in the FMF group at 5 years was significantly lower than in the control group (p = .045). There was no statistically significant difference between the FMF and control groups in terms of graft and patient survival, and serum creatinine levels at 10 years. All patients were given triple immunosuppressive treatment with cyclosporine, mycophenolate mofetil, and prednisolone. Three patients received anakinra and one received canakinumab in addition to colchicine treatment. One FMF patient also underwent heart transplantation due to AA amyloidosis. Of the FMF patients, 11 died during follow-up.

CONCLUSION

We have found that the long-term outcome of KT in patients with FMF amyloidosis is numerically worse but not statistically different from the control group. However, short- and long-term complications still need to be resolved.

Case report: Rapid development of amyloid A amyloidosis in temporal arteritis with SAA1.3 allele; An unusual case of intestinal amyloidosis secondary to temporal arteritis

Temporal arteritis (TA) is a large-vessel vasculitis mostly seen in older patients. Amyloid A (AA) amyloidosis secondary to a chronic inflammation induces multiple organ dysfunctions, including a dysfunction of the gastrointestinal tract. Herein, we present a case of TA complicated by AA amyloidosis that was resistant to oral and intravenous steroids. An 80-year-old man with a history of new-onset headache, jaw claudication, and distended temporal arteries was referred to our department. On admission, the patient presented with tenderness and a subcutaneous temporal nodule in both temple arteries. Ultrasonography of the nodule revealed an anechoic perivascular halo surrounding the right temporal artery. Following the diagnosis of TA, high-dose prednisolone therapy was initiated. However, the patient presented with recurrent abdominal pain and refractory diarrhea. Due to the unclear origin of refractory diarrhea, an extensive workup, including biopsy of the duodenal mucosa, was performed. Endoscopy revealed chronic inflammation in the duodenum. Immunohistochemical analysis of duodenal mucosal biopsy samples revealed AA amyloid deposition resulting in the diagnosis of AA amyloidosis. After tocilizumab (TCZ) administration, refractory diarrhea reduced; however, the patient died of intestinal perforation 1 month after the start of TCZ administration. Gastrointestinal involvement was the main clinical manifestation of AA amyloidosis in the present case. This case highlights the importance of bowel biopsy screening for amyloid deposition in patients with unexplained gastrointestinal tract symptoms, even in a recent onset of large-vessel vasculitis. In the present case, the carriage of the SAA1.3 allele likely contributed to the rare association of AA amyloidosis with TA.

Systemic AA Amyloidosis Secondary to Metastatic Renal Cell Carcinoma in a Hemodialysis Patient with Intractable Diarrhea

We describe an autopsied case of systemic AA amyloidosis secondary to metastatic renal cell carcinoma presenting intractable diarrhea. Severe diarrhea was the major symptom for the diagnosis of AA amyloidosis. No renal symptoms which are common in AA amyloidosis secondary to renal cell carcinoma were shown because hemodialysis following bilateral nephrectomy had already been started 9 years before. Treatment against metastatic tumors as a solution of AA amyloidosis could not be performed because of bad performance status and the patient died 5 months after the diagnosis. Autopsy findings revealed that AA amyloid deposition was seen in multi-organs including the intestine. The metastatic tumors were histologically compatible as metastasis of renal cell carcinoma. There was no other cause of chronic inflammation such as inflammatory arthritis. We concluded that chronic inflammation provoked by the metastatic tumors of renal cell carcinoma was a major cause of systemic AA amyloidosis. Intestinal AA amyloidosis with malabsorption was the cause of death. Clinicians should keep it in mind that solid organ malignancy can be a cause of AA amyloidosis and renal cell carcinoma is the most common carcinomatous cause. This case is particularly instructive in that progression of amyloidosis may be missed in hemodialysis patients with anuria and that gastrointestinal symptoms can be the primary indicators of systemic amyloidosis. Endoscopic examination including biopsy is important for the diagnosis and early treatment of amyloidosis.

Frequency of AA amyloidosis has decreased in Behçet's syndrome: a retrospective study with long-term follow-up and a systematic review

OBJECTIVE

A decline in the frequency of AA amyloidosis secondary to RA and infectious diseases has been reported. We aimed to determine the change in the frequency of AA amyloidosis in our Behçet's syndrome (BS) patients and to summarize the clinical characteristics of and outcomes for our patients, and also those identified by a systematic review.

METHODS

We identified patients with amyloidosis in our BS cohort (as well as their clinical and laboratory features, treatment, and outcome) through a chart review. The primary end points were end-stage renal disease and death. The prevalence of AA amyloidosis was estimated separately for patients registered during 1976-2000 and those registered during 2001-2017, in order to determine whether there was any change in the frequency. We searched PubMed and EMBASE for reports on BS patients with AA amyloidosis. Risk of bias was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) tool.

RESULTS

The prevalence of AA amyloidosis was 0.62% (24/3820) in the earlier cohort and declined to 0.054% (3/5590) in the recent cohort. The systematic review revealed 82 cases in 42 publications. The main features of patients were male predominance and a high frequency of vascular involvement. One-third of patients died within 6 months after diagnosis of amyloidosis.

CONCLUSION

The frequency of AA amyloidosis has decreased in patients with BS, which is similar to the decrease observed for AA amyloidosis due to other inflammatory and infectious causes. However, AA amyloidosis is a rare, but potentially fatal complication of BS.

Macrophages in the reticuloendothelial system inhibit early induction stages of mouse apolipoprotein A-II amyloidosis

Amyloidosis refers to a group of degenerative diseases that are characterized by the deposition of misfolded protein fibrils in various organs. Deposited amyloid may be removed by a phagocyte-dependent innate immune system; however, the precise mechanisms during disease progression remain unclear. We herein investigated the properties of macrophages that contribute to amyloid degradation and disease progression using inducible apolipoprotein A-II amyloidosis model mice. Intravenously injected AApoAII amyloid was efficiently engulfed by reticuloendothelial macrophages in the liver and spleen and disappeared by 24 h. While cultured murine macrophages degraded AApoAII via the endosomal-lysosomal pathway, AApoAII fibrils reduced cell viability and phagocytic capacity. Furthermore, the depletion of reticuloendothelial macrophages before the induction of AApoAII markedly increased hepatic and splenic AApoAII deposition. These results highlight the physiological role of reticuloendothelial macrophages in the early stages of pathogenesis and suggest the maintenance of phagocytic integrity as a therapeutic strategy to inhibit disease progression.

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.