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Biophysical Chemistry Jun 2024Human islet amyloid polypeptide (hIAPP) forms amyloid deposits that contribute to β-cell death in pancreatic islets and are considered a hallmark of Type II diabetes...
Human islet amyloid polypeptide (hIAPP) forms amyloid deposits that contribute to β-cell death in pancreatic islets and are considered a hallmark of Type II diabetes Mellitus (T2DM). Evidence suggests that the early oligomers of hIAPP formed during the aggregation process are the primary pathological agent in islet amyloid induced β-cell death. The self-assembly mechanism of hIAPP, however, remains elusive, largely due to limitations in conventional biophysical techniques for probing the distribution or capturing detailed structures of the early, structurally dynamic oligomers. The advent of Ion-mobility Mass Spectrometry (IM-MS) has enabled the characterisation of hIAPP early oligomers in the gas phase, paving the way towards a deeper understanding of the oligomerisation mechanism and the correlation of structural information with the cytotoxicity of the oligomers. The sensitivity and the rapid structural characterisation provided by IM-MS also show promise in screening hIAPP inhibitors, categorising their modes of inhibition through "spectral fingerprints". This review delves into the application of IM-MS to the dissection of the complex steps of hIAPP oligomerisation, examining the inhibitory influence of metal ions, and exploring the characterisation of hetero-oligomerisation with different hIAPP variants. We highlight the potential of IM-MS as a tool for the high-throughput screening of hIAPP inhibitors, and for providing insights into their modes of action. Finally, we discuss advances afforded by recent advancements in tandem IM-MS and the combination of gas phase spectroscopy with IM-MS, which promise to deliver a more sensitive and higher-resolution structural portrait of hIAPP oligomers. Such information may help facilitate a new era of targeted therapeutic strategies for islet amyloidosis in T2DM.
PubMed: 38941872
DOI: 10.1016/j.bpc.2024.107285 -
The Journal of Hand Surgery Jun 2024Our purpose was to compare differences in the incidence of amyloid deposition in tenosynovium (TS) versus transverse carpal ligament (TCL) biopsies obtained during open...
PURPOSE
Our purpose was to compare differences in the incidence of amyloid deposition in tenosynovium (TS) versus transverse carpal ligament (TCL) biopsies obtained during open carpal tunnel release. We hypothesized that the incidence of amyloid would be similar between TCL and TS when obtaining both specimens from the same patient.
METHODS
All primary, elective open carpal tunnel release cases that underwent biopsy for amyloid between January 2022 and September 2023 were reviewed. Tenosynovial and TCL specimens were independently evaluated by a pathologist to assess for amyloid. Demographic data were collected, and incidence of amyloid deposition was compared between the two samples. Agreement statistics, sensitivity, and specificity were calculated for TCL, using TS as the reference standard.
RESULTS
A total of 196 cases met either Tier 1 (n=180) or Tier 2 (n=16) biopsy criteria. Forty-eight cases were excluded for missed biopsies or laboratory processing errors, leaving 148 cases available for analysis. Amyloid deposition was present in 31 out of 148 (21%) TS specimens and 33 out of 148 (22%) TCL specimens. Overall, the results of the TS biopsy agreed with TCL biopsy in 138 out of 148 cases (93%). In the 10 cases for which the results of the TCL and TS biopsy differed, six cases had (+) TCL and (-) TS, and four cases had amyloid deposition in TS without evidence of deposition in the TCL. Sensitivity and specificity values for the TCL specimen were 87% and 95%, respectively. Positive and negative predictive values were 82% and 97%, respectively.
CONCLUSIONS
For cases of open carpal tunnel release undergoing biopsy, amyloid deposition was noted in 21% of TS specimens and 22% of TCL specimens. Results of TS and TCL biopsies obtained from the same patient agreed in 93% of cases. Single-source biopsy for amyloid represents a reasonable diagnostic approach. Future cost analyses should be performed to determine whether the addition of two biopsy sources to improve diagnostic accuracy is justified.
TYPE OF STUDY/LEVEL OF EVIDENCE
Prognostic II.
PubMed: 38934987
DOI: 10.1016/j.jhsa.2024.05.004 -
The New England Journal of Medicine Jun 2024
Review
Topics: Humans; Immunoglobulin Light-chain Amyloidosis; Immunoglobulin Light Chains; Amyloidosis; Male
PubMed: 38924733
DOI: 10.1056/NEJMra2304088 -
Annals of Neurology Jun 2024Amyloid neuropathy is caused by deposition of insoluble β-pleated amyloid sheets in the peripheral nervous system. It is most common in: (1) light-chain amyloidosis, a... (Review)
Review
Amyloid neuropathy is caused by deposition of insoluble β-pleated amyloid sheets in the peripheral nervous system. It is most common in: (1) light-chain amyloidosis, a clonal non-proliferative plasma cell disorder in which fragments of immunoglobulin, light or heavy chain, deposit in tissues, and (2) hereditary transthyretin (ATTRv) amyloidosis, a disorder caused by autosomal dominant mutations in the TTR gene resulting in mutated protein that has a higher tendency to misfold. Amyloid fibrils deposit in the endoneurium of peripheral nerves, often extensive in the dorsal root ganglia and sympathetic ganglia, leading to atrophy of Schwann cells in proximity to amyloid fibrils and blood-nerve barrier disruption. Clinically, amyloid neuropathy is manifested as a length-dependent sensory predominant neuropathy associated with generalized autonomic failure. Small unmyelinated nerves are involved early and prominently in early-onset Val30Met ATTRv, whereas other ATTRv and light-chain amyloidosis often present with large- and small-fiber involvement. Nerve conduction studies, quantitative sudomotor axon testing, and intraepidermal nerve fiber density are useful tools to evaluate denervation. Amyloid deposition can be demonstrated by tissue biopsy of the affected organ or surrogate site, as well as bone-avid radiotracer cardiac imaging. Treatment of light-chain amyloidosis has been revolutionized by monoclonal antibodies and stem cell transplantation with improved 5-year survival up to 77%. Novel gene therapy and transthyretin stabilizers have revolutionized treatment of ATTRv, improving the course of neuropathy (less change in the modified Neuropathy Impairment Score + 7 from baseline) and quality of life. With great progress in amyloidosis therapies, early diagnosis and presymptomatic testing for ATTRv family members has become paramount. ANN NEUROL 2024.
PubMed: 38923548
DOI: 10.1002/ana.26965 -
The Oncologist Jun 2024Daratumumab-hyaluronidase-fihj (Dara-SQ) is frequently used in the treatment of plasma cell disorders and is associated with improved outcomes. Dara-SQ was shown to be...
BACKGROUND
Daratumumab-hyaluronidase-fihj (Dara-SQ) is frequently used in the treatment of plasma cell disorders and is associated with improved outcomes. Dara-SQ was shown to be non-inferior to intravenous daratumumab (Dara-IV) in efficacy, safety, and associated with fewer administration-related reactions (ARRs). Despite the lower ARR risk with Dara-SQ, package labeling still recommends indefinite premedication. In this study, we investigated the safety of premedication discontinuation after one cycle of Dara-SQ.
MATERIALS AND METHODS
This pre-post interventional quality improvement study included all patients aged 18 years and older diagnosed with multiple myeloma or light chain (AL) amyloidosis who received at least one dose of Dara-SQ. Patients in Arm 1 received Dara-SQ per package labeling, while patients in Arm 2 had premedication omitted (excluding dexamethasone) after cycle 1. The primary endpoint was the incidence of ARR after cycle 1. Overall ARR rate and therapy time saved were also evaluated.
RESULTS
A total of 102 patients (63 in Arm 1 and 39 in Arm 2) were included. There were zero reactions in either arm after cycle 1 across 1479 Dara-SQ doses administered over a 30-month period with or without premedication omission. The overall ARR rate was 2.9% (3/102), which all occurred prior to premedication omission. Therapy timed saved from premedication omission was 194 hours in a 6-month period, equating to approximately $140 000 USD.
CONCLUSION
ARRs to Dara-SQ were rare, mild, and occurred during cycle 1 prior to premedication omission. Omission of noncorticosteroid premedication is safe, feasible, and carries substantial time and cost savings for patients and infusion centers.
PubMed: 38920281
DOI: 10.1093/oncolo/oyae158 -
Annals of the Academy of Medicine,... Nov 2023AL amyloidosis is the most common form of systemic amyloidosis. However, the non-specific nature of presenting symptoms requires the need for a heightened clinical... (Review)
Review
AL amyloidosis is the most common form of systemic amyloidosis. However, the non-specific nature of presenting symptoms requires the need for a heightened clinical suspicion to detect unexplained manifestations in the appropriate clinical setting. Early detection and treatment are crucial as the degree of cardiac involvement emerges as a primary prognostic predictor of survival in a patient with AL amyloidosis. Following the diagnosis of AL amyloidosis with appropriate tissue biopsies, prompt treatment with a bortezomib, cyclophosphamide and dexamethasone-based first-line induction with or without daratumumab should be initiated. The goal of treatment is to achieve the best haematologic response possible, ideally with involved free light chain <20 mg/L, as it offers the best chance of organ function improvement. Treatment should be changed if patients do not achieve a partial response within 2 cycles of treatment or very good partial response after 4 cycles or after autologous stem cell transplant, as achievement of profound and prolonged clonal responses translates to better organ response and long-term outcomes. Early involvement of multidisciplinary subspecialists such as renal physicians, cardiologists, neurologists, and gastroenterologists for optimal maintenance and support of involved organs is recommended for optimal management of patients with AL amyloidosis.
Topics: Humans; Immunoglobulin Light-chain Amyloidosis; Dexamethasone; Singapore; Bortezomib; Cyclophosphamide; Antineoplastic Combined Chemotherapy Protocols; Consensus; Antibodies, Monoclonal; Hematopoietic Stem Cell Transplantation; Stem Cell Transplantation
PubMed: 38920149
DOI: 10.47102/annals-acadmedsg.2023101 -
Annals of the Academy of Medicine,... Nov 2023
Topics: Humans; Immunoglobulin Light-chain Amyloidosis; Quality Improvement
PubMed: 38920144
DOI: 10.47102/annals-acadmedsg.2023370 -
European Heart Journal. Case Reports Jun 2024Previous literature suggests that patients with transthyretin amyloidosis (ATTR) experience a high burden of ventricular arrhythmias. Despite this evidence, optimal...
BACKGROUND
Previous literature suggests that patients with transthyretin amyloidosis (ATTR) experience a high burden of ventricular arrhythmias. Despite this evidence, optimal strategies for arrhythmia prevention and treatment remain subject to debate.
CASE SUMMARY
We report the case of a patient with hereditary ATTR cardiomyopathy who developed recurrent ventricular tachycardia prior to a decline in his left ventricular ejection fraction (LVEF). Although he ultimately received an intracardiac device (ICD) for secondary prevention of ventricular tachycardia, his clinical course begets the question of whether more aggressive arrhythmia prevention upfront could have prevented his global functional decline.
DISCUSSION
Given the advent of new disease-modifying therapies for ATTR, it is imperative to reconsider antiarrhythmic strategies in these patients. New decision tools are needed to decide what additional parameters (beyond LVEF ≤ 35%) may warrant ICD placement for primary prevention of ventricular arrhythmias in these patients.
PubMed: 38912115
DOI: 10.1093/ehjcr/ytae273 -
Journal of the American Heart... Jun 2024Cardiac amyloidosis (CA) is frequently found in older patients with aortic stenosis (AS). However, the prevalence of AS among patients with CA is unknown. The objective...
BACKGROUND
Cardiac amyloidosis (CA) is frequently found in older patients with aortic stenosis (AS). However, the prevalence of AS among patients with CA is unknown. The objective was to study the prevalence and prognostic impact of AS among patients with CA.
METHODS AND RESULTS
We conducted a retrospective analysis of a prospective registry comprising 976 patients with native aortic valves who were confirmed with wild type transthyretin amyloid (ATTRwt), hereditary variant transthyretin amyloid (ATTRv), or immunoglobulin light-chain (AL) CA. CA patients' echocardiograms were re-analyzed focusing on the aortic valve. Multivariable Cox regression analysis was performed to assess the mortality risk associated with moderate or greater AS in ATTRwt CA. The crude prevalence of AS among patients with CA was 26% in ATTRwt, 8% in ATTRv, and 5% in AL. Compared with population-based controls, all types of CA had higher age- and sex-standardized rate ratios (SRRs) of having any degree of AS (AL: SRR, 2.62; 95% Confidence Interval (CI) [1.09-3.64]; ATTRv: SRR, 3.41; 95%CI [1.64-4.60]; ATTRwt: SRR, 10.8; 95%CI [5.25-14.53]). Compared with hospital controls, only ATTRwt had a higher SRR of having any degree of AS (AL: SRR, 0.97, 95%CI [0.56-1.14]; ATTRv: SRR, 1.27; 95%CI [0.85-1.44]; ATTRwt: SRR, 4.01; 95%CI [2.71-4.54]). Among patients with ATTRwt, moderate or greater AS was not associated with increased all-cause death after multivariable adjustment (hazard ratio, 0.71; 95%CI [0.42-1.19]; =0.19).
CONCLUSIONS
Among patients with CA, ATTRwt but not ATTRv or AL is associated with a higher prevalence of patients with AS compared with hospital controls without CA, even after adjusting for age and sex. In our population, having moderate or greater AS was not associated with a worse outcome in patients with ATTRwt.
PubMed: 38904242
DOI: 10.1161/JAHA.124.034723 -
Respirology Case Reports Jun 2024Amyloidosis is a pathological deposition disease that causes a spectrum of organ dysfunction. Pulmonary involvement is generally associated with immunoglobulin light...
Amyloidosis is a pathological deposition disease that causes a spectrum of organ dysfunction. Pulmonary involvement is generally associated with immunoglobulin light chain type (AL) amyloid. Transthyretin (ATTR) amyloid build up in the lung is thought to be a senile disease observed usually as a finding at autopsy. We describe a case of pulmonary ATTR amyloidosis with concurrent mycobacterial tuberculosis infection.
PubMed: 38903946
DOI: 10.1002/rcr2.1418