Cardiac Amyloidosis Associated with Apolipoprotein A-IV Deposition Diagnosed by Mass Spectrometry-Based Proteomic Analysis

Small Bowel Perforation in Roux-en-Y Gastric Bypass (RYGB) Secondary to Apolipoprotein A-IV (AApoA-IV) Type Amyloidosis

BACKGROUND

ApoA-IV amyloidosis is a rare disease that involves the deposition of ApoA-IV protein aggregates in tissues. It commonly presents as cardiac or renal disease, but can, in rare cases, cause small bowel perforation.

METHODS

This study describes a case of ApoA-IV type amyloidosis causing small bowel perforation after conversion of a sleeve gastrectomy (SG) into a RYGB in a Crohn's disease (CD) and rheumatoid arthritis (RA) patient. It also considers the indications for bariatric and anti-reflux surgery in the setting of co-morbid inflammatory bowel disease (IBD), gastro-oesophageal reflux disease (GORD), and obesity.

RESULTS

Obesity can reduce the efficacy of IBD medications and drives a pro-inflammatory state that may worsen IBD, however IBD patients present an operative challenge due to risk of more intestinal adhesions, potential intolerance to intestinal bypass, and risk of affecting options for future bowel resections if required. SG is often chosen over RYGB for CD patients due to limited short-term complications. However, when considering co-morbid GORD, the long-term risk of medication resistant GORD, erosive oesophagitis, and Barrett's oesophagus with SG is significant, especially given that SG is an irreversible procedure.

CONCLUSION

There is growing evidence that bariatric surgery in IBD patients is both safe and effective, however the decision to perform bariatric surgery in an IBD patient involves consideration of the intricate interplay between obesity and IBD.

Amyloid-forming property of the N-terminal 1-70 residues of human apolipoprotein A-IV

Apolipoprotein A-IV (apoA-IV), the largest member of the exchangeable apolipoprotein family, is a common constituent of amyloid deposits in renal and cardiac amyloidosis. In this study, we characterized the aggregation propensity of the apoA-IV N-terminal fragment to form amyloid fibrils using a variety of biophysical techniques. Thioflavin T fluorescence assay, circular dichroism measurement, and microscopic observations revealed that the N-terminal 1-70 amino acid fragment of apoA-IV readily forms amyloid fibrils by a transition from a random coil to a β-sheet-rich structure. Sequence-based analysis indicated that residues 7-16 and 38-42 are the major aggregation-prone segments within the N-terminal 1-70 residues of apoA-IV. Consistent with this, deletion of these residues strongly inhibited the β-transition and fibril formation of apoA-IV 1-70. Kinetic and thermodynamic analyses of fibril formation by the apoA-IV 1-70 fragment demonstrated that primary nucleation is the dominant step in fibril formation, for which the activation energy barrier is entirely entropic. In addition, we found that the presence of heparin, a representative glycosaminoglycan, accelerated fibril formation kinetics and enhanced the yield of apoA-IV 1-70 fibrils, and the positively charged residues K58-K59 play a critical role in heparin interaction. Overall, our results suggest that the strong amyloid-forming propensity of the N-terminal fragment of apoA-IV may play a key role in amyloid deposition associated with apoA-IV amyloidosis.

Identification of apolipoprotein E-derived amyloid within cholesterol granulomas of leopard geckos (Eublepharis macularius)

Apolipoprotein E (ApoE) is involved in cholesterol transport among cells and also plays an important role in amyloid formation, co-depositing with amyloid fibrils in various types of amyloidosis. Although the in vivo amyloidogenicity of ApoE has not been previously demonstrated, this study provides evidence of ApoE amyloidogenicity in leopard geckos (Eublepharis macularius), belonging to the class Reptilia. Histologically, amyloid deposits were localized within cholesterol granulomas and exhibited positive Congo red staining, with yellow to green birefringence under polarized light. On mass spectrometry-based proteomic analysis, ApoE was detected as a dominant component of amyloid; of the full length of the 274 amino acid residues, peptides derived from Leu185-Arg230 were frequently detected with non-tryptic truncations. Immunohistochemistry with anti-leopard gecko ApoE antibody showed positive reactions of amyloid deposits. These results show that ApoE is an amyloid precursor protein within the cholesterol granulomas of leopard geckos. Although further investigations are needed, the C-terminal region of ApoE involved in amyloid formation is a lipid-binding region, and there should be a relationship between amyloidogenesis and the development of cholesterol granulomas in leopard geckos. This study provides novel insights into the pathogenesis of ApoE-related diseases.

Examining the Difficulties in Identifying and Handling Cardiac Amyloidosis; Acquiring Important Knowledge and Robust Treatment Methods

Systemic amyloidosis is a rare protein misfolding and deposition condition that causes slow organ failure. Each of the more than 15 exclusive sorts of systemic amyloidosis, which encourage amyloid production and tissue deposition, is introduced by a unique precursor protein. Amyloidosis can affect various organs, including the heart, kidneys, liver, nerves, gastrointestinal tract, lungs, muscles, skin, and soft tissues. It can either be acquired or hereditary. Insidious and doubtful signs often cause a put-off in diagnosis. In the closing decade, noteworthy progressions have been made in the identity, prediction, and handling of amyloidosis. Shotgun proteomics based on mass spectrometry has revolutionized amyloid typing and enabled the identification of novel amyloid forms. It is critical to correctly identify the precursor protein implicated in amyloidosis because the kind of protein influences the proper treatment strategy. Cardiac amyloidosis is a disorder characterized by the systemic accumulation of amyloid protein in the myocardium's extracellular space, which causes a variety of symptoms. The buildup of amyloid aggregates precipitates myocardial thickening and stiffening, culminating in diastolic dysfunction and, in due course, heart failure. We examine every kind of systemic amyloidosis in this text to offer practitioners beneficial equipment for diagnosing and treating those unusual diseases. This review presents a comprehensive analysis of cardiac amyloidosis and consolidates current methods for screening, diagnosis, evaluation, and treatment alternatives.

Stress Response Is the Main Trigger of Sporadic Amyloidoses

Amyloidoses are a group of diseases associated with the formation of pathological protein fibrils with cross-β structures. Approximately 5-10% of the cases of these diseases are determined by amyloidogenic mutations, as well as by transmission of infectious amyloids (prions) between organisms. The most common group of so-called sporadic amyloidoses is associated with abnormal aggregation of wild-type proteins. Some sporadic amyloidoses are known to be induced only against the background of certain pathologies, but in some cases the cause of amyloidosis is unclear. It is assumed that these diseases often occur by accident. Here we present facts and hypotheses about the association of sporadic amyloidoses with vascular pathologies, trauma, oxidative stress, cancer, metabolic diseases, chronic infections and COVID-19. Generalization of current data shows that all sporadic amyloidoses can be regarded as a secondary event occurring against the background of diseases provoking a cellular stress response. Various factors causing the stress response provoke protein overproduction, a local increase in the concentration or modifications, which contributes to amyloidogenesis. Progress in the treatment of vascular, metabolic and infectious diseases, as well as cancers, should lead to a significant reduction in the risk of sporadic amyloidoses.

A systemic apolipoprotein A-IV-associated amyloidosis confirmed by proteome analysis

Amyloidosis is induced by extracellular deposition of certain proteins. Thirty-six proteins have so far been identified as amyloidogenic proteins in humans. Although it is very important to determine the specific amyloid protein type for the choice of therapy for amyloidosis patient, it might be difficult to identify specific proteins from amyloid-deposited tissue. Apolipoprotein A-IV is known as an amyloid-associated protein, but there have been few reports of apolipoprotein A-IV amyloidosis. Here we report a case of systemic apolipoprotein A-IV-associated amyloidosis that was confirmed by proteome analysis using formalin-fixed paraffin-embedded tissue and an immunohistochemical technique.