Amyloidosis-the Diagnosis and Treatment of an Underdiagnosed Disease

AL type renal amyloidosis with cardiac involvement: A case report and literature review

RATIONALE

Systemic amyloidosis refers to a spectrum of diseases characterized by extracellular deposition of amyloids, with commonrenal involvement; however, simultaneous involvement of cardiac amyloidosis remains rare. The purpose of this report was to enhance the understanding of the diagnosis and treatment of light chain (AL)-type renal amyloidosis with cardiovascular involvement, reduce misdiagnosis and missed diagnosis, and enable timely and effective treatment for such patients.

PATIENT CONCERNS

A 74-year-old male patient was admitted to our hospital because of recurrent edema for over 1 year and aggravated recurrence with decreased urine for 1 month. Pathological examination of the renal biopsy specimen showed homogeneous nonstructural material deposition in the glomerular mesangial area.

DIAGNOSES

This patient was diagnosed with lightchain (AL)-type renal amyloidosis with cardiac involvement.

INTERVENTIONS

Treatment with daretomumab (DARA) 800mg plus cyclophosphamide 0.4g, bortezomib 1.6mg and dexamethasone 20mg (D-VCD regimen). Interventions, such as intermittent diuresis, anticoagulation, and electrolyte imbalance, were administered.

OUTCOMES

After 2 courses of chemotherapy, edema was relieved, urine protein was reduced, and symptoms improved. Chemotherapy was continued in accordance with the regimen described above.

LESSONS

Due to the rarity and nonspecific symptoms, missed diagnosis and misdiagnosis of AL-type renal amyloidosis remain common. Among patients with a confirmed diagnosis, in addition to considering the pathological changes in the kidney, consideration of the presence of amyloidosis in other organs, such as cardiac involvement, is also necessary.

Mass Spectrometry-Based Proteomics in Clinical Diagnosis of Amyloidosis and Multiple Myeloma: A Review (2012-2024)

Proteomics is nowadays increasingly becoming part of the routine clinical practice of diagnostic laboratories, especially due to the advent of advanced mass spectrometry techniques. This review focuses on the application of proteomic analysis in the identification of pathological conditions in a hospital setting, with a particular focus on the analysis of protein biomarkers. In particular, the main purpose of the review is to highlight the challenges associated with the identification of specific disease-causing proteins, given their complex nature and the variety of posttranslational modifications (PTMs) they can undergo. PTMs, such as phosphorylation and glycosylation, play critical roles in protein function but can also lead to diseases if dysregulated. Proteomics plays an important role especially in various medical fields ranging from cardiology, internal medicine to hemato-oncology emphasizing the interdisciplinary nature of this field. Traditional methods such as electrophoretic or immunochemical methods have been mainstay in protein detection; however, these techniques are limited in terms of specificity and sensitivity. Examples include the diagnosis of multiple myeloma and the detection of its specific protein or amyloidosis, which relies heavily on these conventional methods, which sometimes lead to false positives or inadequate disease monitoring. Mass spectrometry in this respect emerges as a superior alternative, providing high sensitivity and specificity in the detection and quantification of specific protein sequences. This technique is particularly beneficial for monitoring minimal residual disease (MRD) in the diagnosis of multiple myeloma where traditional methods fall short. Furthermore mass spectrometry can provide precise typing of amyloid proteins, which is crucial for the appropriate treatment of amyloidosis. This review summarizes the opportunities for proteomic determination using mass spectrometry between 2012 and 2024, highlighting the transformative potential of mass spectrometry in clinical proteomics and encouraging its wider use in diagnostic laboratories.

Demographic and regional trends in systemic and cardiovascular amyloidosis-related mortality among older adults in the United States from 1999 to 2020

Despite therapy advancements, amyloidosis mortality rates for older adults (aged ≥ 65) are rising. This study analyzes trends in amyloidosis-related mortality among older adults in the U.S. We conducted a cross-sectional analysis of death certificates from the CDC WONDER database for amyloidosis-related deaths from 1999 to 2020. Age-adjusted mortality rates (AAMRs) per 100,000 persons and annual percent change (APC) were calculated by age, race/ethnicity, urban-rural classification, and region. From 1999 to 2020, AAMR for amyloidosis in older adults (aged ≥ 65) in the U.S. increased from 2.7 to 5.6. Men consistently had higher AAMRs than women (men: 3.7 vs. women: 2.2 in 1999; men: 8.5 vs. women: 3.5 in 2020). In 2020, Non-Hispanic Blacks had the highest AAMR at 11.8, with an APC of 19.8 (95% CI 10.5-25.5). Regional differences were notable, with AAMRs highest in the Northeast (6.9) and lowest in the South (4.2). Large metropolitan areas had a higher AAMR (6.3) than non-metropolitan areas (4.6). Cardiac amyloidosis accounted for 68.8% of deaths, with AAMR rising from 1.7 to 4.2. There has been a significant increase in AAMRs for amyloidosis in the U.S. from 1999 to 2020, particularly among males, Non-Hispanic Blacks, and those in large metropolitan and Northeast areas. These findings stress the need for enhanced prevention and treatment strategies for older adults.

Global patterns of amyloid typing: results of a survey by the International Society of Amyloidosis (ISA)

BACKGROUND

Accurate tissue typing in amyloidosis is essential to provide appropriate therapy for individual patients.

OBJECTIVE

To get a real-life overview of typing strategies worldwide.

METHODS

The International Society of Amyloidosis (ISA) performed an online questionnaire survey among ISA members. We prepared questionnaire sheets for referral institutions (Category 1; C1), institutions performing amyloid typing for internal requests only (C2), and institutions outsourcing amyloid typing to referral institutions (C3), respectively.

RESULTS

Seventy-six institutions participated in this survey, including C1 (n = 33), C2 (n = 20) and C3 (n = 23) institutions. Multiple typing methods were available across the responding institutions, including immunohistochemistry (85% of C1/C2 institutions), immunofluorescence microscopy (43%), genetic analysis (77%) and mass spectrometric analysis (42%). Commercial antibodies were used worldwide for immunohistochemistry. C1 institutions in Europe and Asia also used various in-house antibodies. Ninety-three percent of institutions performed genetic analysis of TTR gene, followed by APOA1 (43%), FGA, GSN, LYZ (33%) and APOA2 (31%). Hierarchical referral flows of mass spectrometric analysis, immunohistochemistry and genetic analysis were observed regionally and internationally. Globalization and centralization of referral flows were more prominent for mass spectrometric analysis.

CONCLUSION

These data provide an assessment of the current state, enabling improvement in capabilities of amyloid typing worldwide and enhancing regional/international networks.

Exploring the Utility of Carpal Tunnel Biopsy in Amyloidosis: A Current Perspective

Recent literature has emphasized the role of hand surgeons in screening patients with carpal tunnel syndrome (CTS) for amyloidosis by performing a carpal tunnel synovial biopsy during open carpal tunnel release (CTR). This has led to misconceptions about the diagnostic utility of synovial biopsy and the clinical evaluation of suspected amyloidosis. Controversy over carpal tunnel biopsy is exacerbated by minimally invasive advances in CTR procedures. This current perspective aims to determine the role of carpal tunnel synovial biopsy in amyloidosis and provide an update for hand surgeons regarding the nuances of amyloidosis. We conclude that carpal tunnel synovial biopsy should not be performed without CTS symptoms but only in patients meeting criteria for open CTR such as in those with severe symptoms which have failed nonoperative treatment and minimally invasive procedures are contraindicated. A screening approach for amyloidosis is proposed in patients presenting with CTS symptoms. Despite advances in the understanding, treatment, and diagnosis of amyloidosis, there remains a need for accurate, specific, and sensitive diagnostic tests.

Neutrophils enhance the clearance of systemic amyloid deposits in a murine amyloidoma model

Introduction

Amyloid-specific antibodies have been shown to opsonize and enhance amyloid clearance in systemic amyloidosis mouse models. However, the immunological mechanisms by which amyloid is removed have not been clearly defined. Previous reports from preclinical in vivo studies suggest polymorphonuclear cells (i.e., neutrophils) can affect amyloid removal. Therefore, we sought to analyze how neutrophils may contribute to the clearance of human AL amyloid extracts, using a murine amyloidoma model.

Methods

Immunocompromised nude mice injected subcutaneously with patient-derived AL amyloid extract (generating a localized "amyloidoma") were used to circumvent confounding factors contributed by the adaptive immune system and served as the model system. Two representative AL amyloid extracts were used, ALλ(CLA), which is refractory to clearance, and ALκ(TAL), which is readily cleared in mice. Neutrophil recruitment to the amyloid masses, cellular activation, and propensity to engulf amyloid were assessed.

Results

Immunophenotyping of amyloidomas from animals implanted with 2 mg of either ALλ or ALκ revealed that more neutrophils were recruited to ALκ amyloid masses as compared to the ALλ material, which was generally devoid of neutrophils. Ex vivo analyses indicated neutrophils do not efficiently phagocytose amyloid directly. However, histological evaluation of the ALκ amyloidoma revealed the abundant presence of neutrophil extracellular traps, which were absent in the ALλ amyloidomas. Using neutrophil depletion experiments in mice, we determined that mice devoid of neutrophils cleared the human amyloid lesions less efficiently. Moreover, mice devoid of neutrophils also had significantly reduced intra-amyloid expression of inflammatory cytokines.

Discussion

Neutrophils may not directly mediate amyloid clearance through phagocytosis; however, these cells can be stimulated by the amyloid and may function to facilitate phagocytosis and amyloid clearance by professional phagocytes (e.g., macrophages).

Liver stiffness as a prognostic parameter and tool for risk stratification in advanced cardiac transthyretin amyloidosis

BACKGROUND

In light of increasing therapeutic options, risk stratification of advanced cardiac transthyretin amyloidosis (ATTR-CA) is gaining clinical importance to avoid ineffective treatments. Liver stiffness as a marker of hypervolemia and hepatic congestion might predict mortality in advanced ATTR-CA and allow to identify patients at highest risk.

METHODS

Proven ATTR-CA patients underwent repeated vibration-controlled transient elastography (VTCE) and standardized serial workup within the local amyloidosis cohort study AmyKoS. Spearman correlation analyses and Cox regressions were performed to evaluate the prognostic value.

RESULTS

41 patients with ATTR-CA were included with median age of 76.6 (55.1-89.1) years, of which 90.2% were male and > 92% wild-type ATTR-CA. In total, 85 VCTE examinations were performed. Median follow-up was 43.7 (2.4-75.6) months; 26.8% of the patients died. At the first clinical evaluation, median left ventricular (LV) absolute global longitudinal strain (GLS) was 11.4 (5.2-19.0) % and median liver stiffness was 6.3 (2.4-22.9) kPa, both significantly correlated with mortality. NT-proBNP possessed statistically significant predictive power in ATTR-CA with more preserved LV function (absolute GLS ≥ 10), whereas stiffness seemed to be more discriminative for ATTR-CA with absolute GLS < 10. The use of alternative congestion surrogates such as liver vein dilation and tricuspid regurgitation peak velocity (tr-vmax) showed congruent results.

CONCLUSION

Liver stiffness shows prognostic value regarding all-cause mortality and allows risk stratification in advanced ATTR-CA, particularly in those with markedly impaired longitudinal LV function. These results are transferable to other congestion surrogates.

Incremental prognostic utility of congestion markers in cardiac transthyretin amyloidosis

BACKGROUND/AIMS

Congestion is prognostically relevant in cardiac transthyretin amyloidosis (ATTR-CA), but whether congestion has an incremental prognostic value beyond the well-established, congestion-sensitive NT-proBNP is unknown. Therefore, we aimed to comparatively evaluate the prognostic utility of several congestion surrogates over NT-proBNP.

METHODS

We estimated hazard ratios by Cox proportional hazards regressions with time-varying covariates from a panel data set of the local amyloidosis cohort study AmyKoS. Different models were compared by using chi(χ)2-statistics measuring overall model significance.

RESULTS/CONCLUSION

131 ATTR-CA patients (wild-type 84.0%, hereditary 6.9%, without genetic testing 9.2%; median age 78.7 (quartiles 73.3, 82.1) years; 85.5% male) with 566 observations across a median follow-up of 38.2 (30.6; 48.2) months were analyzed. 83.2% received disease-modifying treatment; 20.6% participated concurrently in placebo-controlled gene silencer trials. Information on congestion improved biomarker-driven risk stratification and identified patients at the highest risk. Echocardiographic congestion markers performed better than clinical findings and daily diuretic use/dosage. Relevant adjusters were daily diuretic dosage, disease-modifying treatment, eGFR, and right atrial volume. NT-proBNP and the tricuspid regurgitation peak velocity (tr-vmax) provided an easy-to-use stratification with overall model performance similar to NAC and Mayo staging systems. Further analyses are necessary for validation and to identify the optimal cut points of the congestion markers.

Feasibility of MALDI-MSI-Based Proteomics Using Bouin-Fixed Pathology Samples: Untapping the Goldmine of Nephropathology Archives

The application of innovative spatial proteomics techniques, such as those based upon matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) technology, has the potential to impact research in the field of nephropathology. Notwithstanding, the possibility to apply this technology in more routine diagnostic contexts remains limited by the alternative fixatives employed by this ultraspecialized diagnostic field, where most nephropathology laboratories worldwide use bouin-fixed paraffin-embedded (BFPE) samples. Here, the feasibility of performing MALDI-MSI on BFPE renal tissue is explored, evaluating variability within the trypsin-digested proteome as a result of different preanalytical conditions and comparing them with the more standardized formalin-fixed paraffin-embedded (FFPE) counterparts. A large proportion of the features (270, 68.9%) was detected in both BFPE and FFPE renal samples, demonstrating only limited variability in signal intensity (10.22-10.06%). Samples processed with either fixative were able to discriminate the principal parenchyma regions along with diverse renal substructures, such as glomeruli, tubules, and vessels. This was observed when performing an additional "stress test", showing comparable results in both BFPE and FFPE samples when the distribution of several amyloid fingerprint proteins was mapped. These results suggest the utility of BFPE tissue specimens in MSI-based nephropathology research, further widening their application in this field.

Immunoglobulin light chain amyloidosis: 2024 update on diagnosis, prognosis, and treatment

DISEASE OVERVIEW

Immunoglobulin light chain amyloidosis is a clonal, nonproliferative plasma cell disorder in which fragments of immunoglobulin light or heavy chain are deposited in tissues. Clinical features depend on organs involved but can include heart failure with preserved ejection fraction, nephrotic syndrome, hepatic dysfunction, peripheral/autonomic neuropathy, and "atypical smoldering multiple myeloma or MGUS."

DIAGNOSIS

Tissue biopsy stained with Congo red demonstrating amyloid deposits with apple-green birefringence is required for the diagnosis of AL amyloidosis. Organ biopsy is not required in 85% of patients. Verification that amyloid is composed of immunoglobulin light chains is mandatory. The gold standard is laser capture mass spectroscopy.

PROGNOSIS

N-terminal pro-brain natriuretic peptide (NT-proBNP or BNP), serum troponin T(or I), and difference between involved and uninvolved immunoglobulin free light chain values are used to classify patients into four stages; 5-year survivals are 82%, 62%, 34%, and 20%, respectively.

THERAPY

All patients with a systemic amyloid syndrome require therapy to prevent deposition of amyloid in other organs and prevent progressive organ failure. Current first-line therapy with the best outcome is daratumumab, bortezomib, cyclophosphamide, and dexamethasone. The goal of therapy is a ≥VGPR. In patients failing to achieve this depth of response options for consolidation include pomalidomide, stem cell transplantation, venetoclax, and bendamustine.

FUTURE CHALLENGES

Delayed diagnosis remains a major obstacle to initiating effective therapy prior to the development of end-stage organ failure. Trials of antibodies to deplete deposited fibrils are underway.

Occupational practice in patients with hereditary transthyretin amyloidosis, a qualitative study

BACKGROUND

Hereditary transthyretin amyloidosis (ATTRv) is a rare genetic disease that negatively affects patients' quality of life through the involvement of various organs and tissues. Despite a large amount of research on medical and psychosocial interventions, the impact of occupational therapy (OT) on patients with ATTRv is not well understood.

OBJECTIVE

The aim of this study was to develop an OT programme to improve the daily functioning and quality of life of patients with ATTRv.

METHODS

Fourteen patients with ATTRv were interviewed. Together they developed short- and medium-term occupational goals. Patients received the OT intervention for six months. Outcomes were measured using scores for activities of daily living and psychological well-being.

RESULTS

The study found that OT can have a positive impact as a complementary intervention to medical and other psychosocial treatments. Of the 14 patients, 12 maintained the same scores in activities of daily living. Two deteriorated and eight improved their psychological scores.

CONCLUSION

This study highlights the need for further research in this area and the importance of OT in the management of patients with ATTRv. Early intervention is of paramount importance and further research is needed to evaluate the long-term effects of OT interventions in patients with ATTRv.

[Giant tongue leading to dysphagia in light chain amyloidosis patient]

Introduction

Macroglossia as a clinical manifestation of systemic amyloidosis is a rare condition, occurring in less than 9% of all types of amyloidosis. The aim of this report is to present the diagnostic approach of a patient with macroglossia, providing a systematic approach and considering relevant diagnostic possibilities during their evaluation.

Clinical case

We present the case of a 60-year-old man who presented with a progressively enlarging giant tongue for six months, causing dysphagia and reduced oral opening. A tongue biopsy was taken, which histopathologically exhibited homogenous eosinophilic amyloid-like material. Congo red staining showed amyloid material with red dye under light microscopy and apple-green birefringence under polarized light. Bone marrow biopsy showed 30% plasma cells, allowing for a definitive diagnosis of soft tissue amyloidosis. Although it is a benign lesion, localized amyloidosis should be differentiated from systemic forms.

Conclusions

The approach of patients with macroglossia is complex due to the diagnostic possibilities, from endocrinological causes, neoplastic, and even by deposit; Being an isolated sign in a patient is a challenge in its approach, because the involvement of the airway is the main complication to avoid in these patients.

Patient Journey Toward a Diagnosis of Light Chain Amyloidosis in a National Sample: Cross-Sectional Web-Based Study

BACKGROUND

Systemic light chain (AL) amyloidosis is a rare and multisystem disease associated with increased morbidity and a poor prognosis. Delayed diagnoses are common due to the heterogeneity of the symptoms. However, real-world insights from Chinese patients with AL amyloidosis have not been investigated.

OBJECTIVE

This study aimed to describe the journey to an AL amyloidosis diagnosis and to build an in-depth understanding of the diagnostic process from the perspective of both clinicians and patients to obtain a correct and timely diagnosis.

METHODS

Publicly available disease-related content from social media platforms between January 2008 and April 2021 was searched. After performing data collection steps with a machine model, a series of disease-related posts were extracted. Natural language processing was used to identify the relevance of variables, followed by further manual evaluation and analysis.

RESULTS

A total of 2204 valid posts related to AL amyloidosis were included in this study, of which 1968 were posted on haodf.com. Of these posts, 1284 were posted by men (median age 57, IQR 46-67 years); 1459 posts mentioned renal-related symptoms, followed by heart (n=833), liver (n=491), and stomach (n=368) symptoms. Furthermore, 1502 posts mentioned symptoms related to 2 or more organs. Symptoms for AL amyloidosis most frequently mentioned by suspected patients were nonspecific weakness (n=252), edema (n=196), hypertrophy (n=168), and swelling (n=140). Multiple physician visits were common, and nephrologists (n=265) and hematologists (n=214) were the most frequently visited specialists by suspected patients for initial consultation. Additionally, interhospital referrals were also commonly seen, centralizing in tertiary hospitals.

CONCLUSIONS

Chinese patients with AL amyloidosis experienced referrals during their journey toward accurate diagnosis. Increasing awareness of the disease and early referral to a specialized center with expertise may reduce delayed diagnosis and improve patient management.

Differential Diagnosis and Therapeutic Advances in Multiple Myeloma: A Review Article

Multiple myeloma (MM) is a hematologic malignancy characterized by the abnormal clonal proliferation of plasma cells that may result in focal bone lesions, renal failure, anemia, and/or hypercalcemia. Recently, the diagnosis and treatment of MM have evolved due to a better understanding of disease pathophysiology, improved risk stratification, and new treatments. The incorporation of new drugs, including proteasome inhibitors, immunomodulatory drugs, anti-CD38 antibodies and high-dose chemotherapy followed by hematopoietic stem cell transplantation, has resulted in a significant improvement in patient outcomes and QoL. In this review, we summarize differential diagnoses and therapeutic advances in MM.

Diagnosis and referral of patients with AL amyloidosis in Portugal: results from a Delphi panel

Light chain amyloidosis (AL) is a complex disorder defined by the extracellular deposition of insoluble amyloid fibrils formed by intact or fragmented immunoglobulin light chains, leading to cell dysfunction, rapid organ deterioration, and, ultimately, death. Although the clinical presentation of AL is directly connected to organ involvement, signs and symptoms of AL are frequently nonspecific, misinterpreted, and late recognized. Thus, an early diagnosis combined with effective therapies to cease disease progression and rescue organ function is essential. The aim of this study was to assess the knowledge and characterize the current clinical practice regarding AL diagnosis and referral among Portuguese physicians. A Delphi-like panel (one round only) with a group of national experts from different medical specialties (cardiology, hematology, internal medicine, nephrology, and neurology) was carried out online, in which 30 statements were classified using a 4-point Likert scale. For each statement, the consensus level was set at 70% for "fully agree/disagree" and the majority level was defined as >70% in agreement or disagreement. Although the results suggest the existence of adequate general knowledge of AL amyloidosis, they also disclosed the necessity to raise awareness for this disease. Overall, this Delphi panel revealed a high lack of consensus regarding the diagnosis and early management of patients with AL among different specialties despite the qualified majority obtained in 26 statements. An optimized strategy for AL early diagnosis, transversal to several medical fields, is urgently needed. Moreover, referral centers with access to diagnostic technology and a network of diverse specialties should be established to foster an early diagnosis and better disease approach to boost the possibility of a better outcome for patients with AL.

Membranous nephropathy with systemic light-chain amyloidosis of remission after rituximab therapy: A case report

BACKGROUND

About 70%-80% of patients with primary membranous nephropathy (MN) have phospholipase A2 receptor (PLA2R) in renal tissue. Systemic light-chain (AL) amyloidosis is the most common type of amyloidosis. MN complicated with amyloidosis is rare.

CASE SUMMARY

A 48-year-old Chinese male presented with nephrotic syndrome, positive serum PLA2R antibody, and positive serum and urine IgG-lambda type M-protein, with a normal ratio of serum-free light-chain level. The patient was diagnosed with MN accompanied by AL amyloidosis. He was treated with rituximab with glucocorticoids and CyBorD regimen of chemotherapy. After 21 mo of follow-up, the patient achieved complete remission regarding nephrotic syndrome without adverse effects of chemotherapy.

CONCLUSION

We report a case of PLA2R-related MN complicated with primary AL amyloidosis only with renal involvement and successfully treated with rituximab, glucocorticoids and chemotherapy.

Extensive Amyloid Purpura: An Unusual Presentation of Myeloma-associated Light Chain Amyloidosis

Abstract is missing (Short communication)

Need for Early Recognition of Amyloidosis in Cases of Unexplained Heart Failure: A Case Report

Amyloidosis is a plasma cell dyscrasia that leads to the excessive production and deposition of mutant protein fragments in various organs. Cardiac amyloidosis is often implicated in two main subtypes: transthyretin (ATTR) and light chain (AL). While both subtypes increase the risk of restrictive cardiomyopathy, cardiogenic shock, and arrhythmias, poorer outcomes are seen in those with cardiac infiltration secondary to AL amyloidosis. Prognosis depends on the timing of diagnosis and the extent of the disease burden prior to recognition and treatment. The following case report describes a young patient who was admitted to the intensive care unit (ICU) for concerns of decompensated heart failure of unknown etiology, later determined to be due to amyloidosis. We describe her clinical course prior to and during hospital admission, along with the proposed physiologic factors that may have contributed to her poor outcome.

An objective assessment in newly diagnosed multiple myeloma to avoid treatment complications and strengthen therapy adherence

In heterogeneous multiple myeloma (MM) patients treatment decisions are challenging. The hypothesis was that adaptation of treatment intensity (dose reduction [DR] vs. none) according to an objective risk score (revised-myeloma comorbidity index [R-MCI]) rather than physician judgement alone may improve therapy efficacy and avoid toxicities. We performed this study in 250 consecutive MM patients who underwent a prospective fitness assessment at our center, after having received induction protocols based on physicians' judgement. DR, serious adverse events (SAE), response, progression-free survival (PFS) and overall survival (OS) were compared in fitness (fit, intermediate-fit, frail), age (<60, ≥70 years [y]) and therapy intensity subgroups at baseline and follow-up. Fit and <60 y patients were mostly treated with full intensity, whereas frail and ≥70 y patients usually received DR. Hematological and non-hematological SAE were more frequently seen in frail versus ≥70 y patients. Dose adaptations were mainly necessary in frail patients. OS and PFS were similar in fit and intermediate-fit but significantly worse in frail patients (P=0.0245/P<0.0001), whereas in age-based subgroups, OS and PFS differences did not reach significance (P=0.1362/P=0.0569). Non-hematological SAE were another negative predictor for impaired OS and PFS (P=0.0054/P=0.0021). In the follow-up performed at a median of 11 months after the first fitness assessment, the R-MCI improved or remained stable in 90% versus deteriorated in only 10% of patients. In conclusion, separation by R-MCI/frailty-defined subgroups was superior to age-based subgroups and can be used to improve tailored treatment. Fitter patients benefit from intensive therapies, whereas frail patients bear a need for initial DR.

A molecular basis for tetramer destabilization and aggregation of transthyretin Ala97Ser

Transthyretin (TTR)-related amyloidosis (ATTR) is a syndrome of diseases characterized by the extracellular deposition of fibrillar materials containing TTR variants. Ala97Ser (A97S) is the major mutation reported in Taiwanese ATTR patients. Here, we combine atomic resolution structural information together with the biochemical data to demonstrate that substitution of polar Ser for a small hydrophobic side chain of Ala at residue 97 of TTR largely influences the local packing density of the FG-loop, thus leading to the conformational instability of native tetramer, the increased monomeric species, and thus the enhanced amyloidogenicity of apo-A97S. Based on calorimetric studies, the tetramer destabilization of A97S can be substantially altered by interacting with native stabilizers via similarly energetic patterns compared to that of wild-type (WT) TTR; however, stabilizer binding partially rearranges the networks of hydrogen bonding in TTR variants while FG-loops of tetrameric A97S still remain relatively flexible. Moreover, TTR in complexed with holo-retinol binding protein 4 is slightly influenced by the structural and dynamic changes of FG-loop caused by A97S substitution with an approximately five-fold difference in binding affinity. Collectively, our findings suggest that the amyloidogenic A97S mutation destabilizes TTR by increasing the flexibility of the FG-loop in the monomer, thus modulating the rate of amyloid fibrillization.

Ethnic/racial differences in risk factors and clinical outcomes among patients with amyloidosis

BACKGROUND

Cardiac amyloidosis is caused by abnormal extracellular deposition of insoluble fibrils in cardiac tissue. It can be fatal when untreated and is often underdiagnosed. Understanding the ethnic/racial differences in risk factors is critical for early diagnosis and treatment to improve clinical outcomes.

METHODS

We performed a retrospective cross-sectional study utilizing the National Inpatient Sample database from 2015 to 2018 using ICD-10-CM codes. The primary variables of interest were race/ethnicity and amyloidosis subtypes, while the primary outcomes were in-hospital mortality, gastrointestinal bleeding, renal failure, and hospital length-of-stay.

RESULTS

Amyloidosis was reported in 0.17% of all hospitalizations (N  =  19,678,415). Of these, 0.09% were non-Hispanic whites, 0.04% were non-Hispanic blacks, and 0.02% were Hispanic. Hospitalizations with ATTR amyloidosis subtype were frequently observed in older individuals and males with coronary artery disease, whereas AL amyloidosis subtype was associated with non-Hispanic whites, congestive heart failure, and longer hospital length of stay. Renal failure was associated with non-Hispanic blacks (adjusted relative risk [RR]  =  1.31, p < 0.001), Hispanics (RR  =  1.08, p  =  0.028) and had an increased risk of mortality. Similarly, the hospital length of stay was longer with non-Hispanic blacks (RR  =  1.19, p < 0.001) and Hispanics (RR  =  1.05, p  =  0.03) compared to non-Hispanic whites. Hispanics had a reduced risk of mortality (RR  =  0.77, p  =  0.028) compared to non-Hispanic whites and non-Hispanic blacks, and no significant difference in mortality was seen between non-Hispanic whites and non-Hispanic blacks (RR  =  1.00, p  =  0.963).

CONCLUSIONS

Our findings highlight significant ethnic/racial differences in risk factors and outcomes among amyloidosis-related US hospitalizations that can possibly be used for early detection, treatment, and better clinical outcomes.

Isolated amyloidosis of the gastro-intestinal tract

Amyloidosis is a very rare condition, which, due to its rarity, is often missed or diagnosed in an advanced stage of the disease, causing significant morbidity and mortality. In this review we describe the existing types of amyloidosis focusing on the gastro-intestinal tract. Amyloidosis occurs when abnormal protein fibrils (amyloid) deposit in the muscularis mucosae. This can cause an array of symptoms ranging from (in order of occurrence): gastro-intestinal bleeding, heartburn, unintentional weight loss, early satiety, constipation, diarrhea, nausea, vomiting and fecal incontinence (1). Treatment is focused on the underlying condition (if any) causing the production and deposition of the abnormal fibrils, in combination of symptomatic treatment.

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.