Diagnosis of Senile Amyloidosis by Fine Needle Aspiration Biopsy and Cell Block from Abdominal Fat Pad

Background: Amyloidosis is menacingly increasing medical problem in aging population across globe. Its clinical presentation is varied. Its laboratory diagnosis often requires biopsy material. The fine needle aspiration cytology (FNAC, FNAB) offers dependable diagnostic alternative to cumbersome biopsy. Present protocol describes the FNAC of abdominal pad of fat as surrogate site for diagnosis of senile systemic amyloidosis avoiding biopsy other known sites. Aim: To study diagnostic accuracy of subcutaneous abdominal fat tissue fine needle aspiration cytology/biopsy for detecting systemic (senile) amyloidosis and its utility in clinical practice. Objectives: To diagnose systemic amyloidosis (senile) by fine needle aspiration cytology/biopsy of abdominal fat pad on crush smears of aspirates and cell blocks. To correlate the diagnosis of deposits of amyloid with the clinical manifestations in specific and non specific clinical manifestations of amyloidosis. To know the sensitivity and specificity of the diagnosis of amyloid deposition on fine needle aspiration cytology/biopsy of abdominal fat pad in comparison to the results of cell block preparations. Methodology: A prospective study carried out to compare results of FNAC of abdominal pad of fat with paraffin embedded cell block in diagnosis of amyloidosis in suspected cases of cases of senile systemic amyloidosis. Technical adopted methods to be used are regular tissue stains, congo red stain and polarized microscopy. Expected Results: It is expected that results of study will establish FNAC of abdominal pad of fat as dependable office diagnostic procedure that would avoid complicated biopsy procedures of gastrointestinal tissue, skin, bone marrow and others for senile systemic amyloidosis.

Transthyretin Misfolding, A Fatal Structural Pathogenesis Mechanism

Transthyretin (TTR) is an essential transporter of a thyroid hormone and a holo-retinol binding protein, found abundantly in human plasma and cerebrospinal fluid. In addition, this protein is infamous for its amyloidogenic propensity, causing various amyloidoses in humans, such as senile systemic amyloidosis, familial amyloid polyneuropathy, and familial amyloid cardiomyopathy. It has been known for over two decades that decreased stability of the native tetrameric conformation of TTR is the main cause of these diseases. Yet, mechanistic details on the amyloidogenic transformation of TTR were not clear until recent multidisciplinary investigations on various structural states of TTR. In this review, we discuss recent advancements in the structural understanding of TTR misfolding and amyloidosis processes. Special emphasis has been laid on the observations of novel structural features in various amyloidogenic species of TTR. In addition, proteolysis-induced fragmentation of TTR, a recently proposed mechanism facilitating TTR amyloidosis, has been discussed in light of its structural consequences and relevance to acknowledge the amyloidogenicity of TTR.

A serine protease secreted from Bacillus subtilis cleaves human plasma transthyretin to generate an amyloidogenic fragment

Aggregation of human wild-type transthyretin (hTTR), a homo-tetrameric plasma protein, leads to acquired senile systemic amyloidosis (SSA), recently recognised as a major cause of cardiomyopathies in 1–3% older adults. Fragmented hTTR is the standard composition of amyloid deposits in SSA, but the protease(s) responsible for amyloidogenic fragments generation in vivo is(are) still elusive. Here, we show that subtilisin secreted from Bacillus subtilis, a gut microbiota commensal bacterium, translocates across a simulated intestinal epithelium and cleaves hTTR both in solution and human plasma, generating the amyloidogenic fragment hTTR(59–127), which is also found in SSA amyloids in vivo. To the best of our knowledge, these findings highlight a novel pathogenic mechanism for SSA whereby increased permeability of the gut mucosa, as often occurs in elderly people, allows subtilisin (and perhaps other yet unidentified bacterial proteases) to reach the bloodstream and trigger generation of hTTR fragments, acting as seeding nuclei for preferential amyloid fibrils deposition in the heart.

Lacrimal Gland Amyloidosis in an Elderly Patient

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

Senile Systemic Amyloidosis Presenting as Hematuria: A Rare Presentation and Review of Literature

Introduction. Senile systemic amyloidosis is a multisystem disease where wild-type insoluble transthyretin (ATTRwt) protein gets deposited in the tissues leading to organ dysfunction. Methodology. We present the case of a patient who presented with hematuria and bladder involvement by ATTRwt amyloidosis who ultimately died of multiorgan failure. Results. The patient was an 82-year-old white male with a history of ischemic cardiomyopathy (ejection fraction (EF): 20–25%), chronic atrial fibrillation, chronic kidney disease (CKD), and carpal tunnel syndrome who presented with acute hematuria, urinary retention, and progressive fatigue. He underwent cystoscopy and bladder biopsy which was positive on congo-red stain diagnostic for amyloidosis. Echocardiogram demonstrated worsening of EF to 10–15% and concentric left ventricle hypertrophy. MRI was not performed due to underlying CKD. His condition deteriorated during the hospital stay, and he developed cardiogenic shock and progressive liver dysfunction. Infectious workup was negative. Meanwhile, the biochemical investigations (serum protein electrophoresis, immunofixation, and urine kappa/lambda chains) ruled out plasma cell dyscrasias. Mass spectrometry analysis of the bladder biopsy specimen confirmed wild-type transthyretin (ATTRwt) amyloidosis consistent with senile systemic amyloidosis. Due to patients’ extremely poor prognosis, his family wished to focus on patient’s comfort-oriented measures only, and patient passed away shortly thereafter. Conclusion. Senile systemic amyloidosis can rarely present in an atypical fashion such as hematuria. The treatment options are limited in this disease process. Novel therapies are in the early phases of development. Concern also exists that in patients with multiple comorbidities, this entity is under recognized until the more advanced stages.

Phenome-wide association study of TTR and RBP4 genes in 361,194 individuals reveals novel insights in the genetics of hereditary and senile systemic amyloidoses

ABSTRACTTransthyretin (TTR) gene has a causal role in a hereditary form of amyloidosis (ATTRm) and is potentially involved in the risk of senile systemic amyloidosis (SSA). To understand the genetics of ATTRm and SSA, we conducted a phenome-wide association study of TTR gene in 361,194 participants of European descent testing coding and non-coding variants. Among the 382 clinically-relevant phenotypes tested, TTR non-coding variants were associated with 26 phenotypic traits after multiple testing correction. These included signs related to both ATTRm and SSA such as chronic ischaemic heart disease (rs140226130, p=2.00×10−6), heart failure (rs73956431, p=2.74×10−6), atrial fibrillation (rs10163755, p=4.63×10−6), dysphagia (rs2949506, p=3.95×10−6), intestine diseases (rs970866, p=7.14×10−6) and anxiety (rs554521234, p=8.85×10−6). Consistent results were observed for TTR disease-causing mutation Val122Ile (rs76992529) with respect to carpal tunnel syndrome (p=6.41×10−6) and mononeuropathies of upper limbs (p=1.22×10−5). Sex differences were also observed in line with ATTRm and SSA epidemiology. Additionally, we explored possible modifier genes related to TTR function, observing convergent associations of RBP4 variants with the clinical phenotypes associated with TTR locus. In conclusion, we provide novel insights regarding the molecular basis of ATTRm and SSA based on large-scale cohort, expanding our understanding of the phenotypic spectrum associated with TTR gene variation.

Amiloidosi da transtiretina (ATTR): l’altra faccia della medaglia

Transthyretin amyloidosis (ATTR) is becoming an emerging clinical entity, and is currently the most common form of systemic amyloidosis. ATTR consists of two distinct diseases depending on whether the amyloid fibrils derive from the intact molecule of TTR (ATTR wild-type or senile systemic amyloidosis) or from different mutations occurred in the TTR molecule gene (ATTRm). Total-body scintigraphy with diphosphonates has greatly improved the diagnosis in patients with isolated cardiac involvement for both ATTRm and ATTRwt, thus avoiding the need of endomiocardial biopsy in cases without serum and/or urinary monoclonal component (MC). Heart failure alone, or associated with peripheral and autonomic neuropathy, are the main clinical symptoms in these patients. Particular attention must be paid in order to exclude hypertrophic cardiomiopathy or light chain (AL) forms in patients with MC. Today, besides hepatic transplantation, which is almost reserved to patients with early Val30Met neuropathy, many new therapeutic alternatives can be offered to these patients. Tafamidis, a TTR-stabilizer that has recently proved to be effective in cardiac forms of both ATTRm and ATTRwt, is now ready for clinical use. In addition, drugs silencing the TTR messenger RNA should soon be available for treatment. The many therapeutic opportunities available today for ATTR, strenghten even more the need for an early diagnosis of the disease both in ATTRm and ATTRwt.