-
Orphanet Journal of Rare Diseases May 2024There are novel medications approved for the treatment of hereditary transthyretin amyloidosis (ATTRv), classified as transthyretin (TTR) stabilizers or gene silencers....
BACKGROUND
There are novel medications approved for the treatment of hereditary transthyretin amyloidosis (ATTRv), classified as transthyretin (TTR) stabilizers or gene silencers. While many patients may be on both classes of medications, there is no data available on the safety and efficacy of combination therapy.
OBJECTIVES
To describe ATTRv patient and TTR-targeted therapy characteristics in a US cohort, and compare outcomes with combination therapy versus monotherapy.
METHODS
We performed a retrospective cohort study with electronic health record data of patients with ATTRv seen at a single institution between January 2018 and December 2022. We collected data on symptomatology, gene mutation, disease severity, ATTRv treatment, hospitalizations, and mortality.
RESULTS
One hundred sixty-two patients with ATTRv were identified. The average age at diagnosis was 65 years. 86 patients (53%) had the V122I variant. 119 patients were symptomatic, of whom 103 were started on ATTRv-specific treatment. 41 patients (40%) had cardiomyopathy only, and 53 (51%) had a mixed phenotype of cardiomyopathy and neuropathy. 38 patients (37%) received therapy with both a gene silencer and protein stabilizer. 9 patients (15%) in the monotherapy group had two or more cardiac hospitalizations after starting treatment, compared to 3 patients (9%) on combination therapy (p=0.26). The adjusted hazard ratio of all-cause mortality for the patients on combination therapy compared to monotherapy was 0.37 (0.08-1.8, p=0.21).
CONCLUSIONS
While the efficacy is unproven, over one-third of patients with ATTRv are on both a stabilizer and a silencer. There were no safety issues for combination therapy. There was a trend towards improved hospitalizations and survival in patients in the combination group but this was not statistically significant. Larger studies with longer follow-up are necessary to determine benefit of combination therapy.
Topics: Humans; Amyloid Neuropathies, Familial; Male; Female; Retrospective Studies; Aged; Middle Aged; Cohort Studies; Prealbumin; Aged, 80 and over; Adult
PubMed: 38720335
DOI: 10.1186/s13023-024-03198-7 -
Journal of Muscle Research and Cell... May 2024In skeletal muscle, Na,K-ATPase (NKA), a heterodimeric (α/β) P-type ATPase, has an essential role in maintenance of Na and K homeostasis, excitability, and...
In skeletal muscle, Na,K-ATPase (NKA), a heterodimeric (α/β) P-type ATPase, has an essential role in maintenance of Na and K homeostasis, excitability, and contractility. AMP-activated protein kinase (AMPK), an energy sensor, increases the membrane abundance and activity of NKA in L6 myotubes, but its potential role in regulation of NKA content in skeletal muscle, which determines maximum capacity for Na and K transport, has not been clearly delineated. We examined whether energy stress and/or AMPK affect expression of NKA subunits in rat L6 and primary human myotubes. Energy stress, induced by glucose deprivation, increased protein content of NKAα1 and NKAα2 in L6 myotubes, while decreasing the content of NKAα1 in human myotubes. Pharmacological AMPK activators (AICAR, A-769662, and diflunisal) modulated expression of NKA subunits, but their effects only partially mimicked those that occurred in response to glucose deprivation, indicating that AMPK does not mediate all effects of energy stress on NKA expression. Gene silencing of AMPKα1/α2 increased protein levels of NKAα1 in L6 myotubes and NKAα1 mRNA levels in human myotubes, while decreasing NKAα2 protein levels in L6 myotubes. Collectively, our results suggest a role for energy stress and AMPK in modulation of NKA expression in skeletal muscle. However, their modulatory effects were not conserved between L6 myotubes and primary human myotubes, which suggests that coupling between energy stress, AMPK, and regulation of NKA expression in vitro depends on skeletal muscle cell model.
PubMed: 38709429
DOI: 10.1007/s10974-024-09673-9 -
Molecular Pharmaceutics May 2024The molecular structures of nonsteroidal anti-inflammatory drugs (NSAIDs) vary, but most contain a carboxylic acid functional group (RCOOH). This functional group is...
The molecular structures of nonsteroidal anti-inflammatory drugs (NSAIDs) vary, but most contain a carboxylic acid functional group (RCOOH). This functional group is known to be related to the mechanism of cyclooxygenase inhibition and also causes side effects, such as gastrointestinal bleeding. This study proposes a new role for RCOOH in NSAIDs: facilitating the interaction at the binding site II of serum albumins. We used bovine serum albumin (BSA) as a model to investigate the interactions with ligands at site II. Using dansyl-proline (DP) as a fluorescent site II marker, we demonstrated that only negatively charged NSAIDs such as ibuprofen (IBP), naproxen (NPX), diflunisal (DFS), and ketoprofen (KTP) can efficiently displace DP from the albumin binding site. We confirmed the importance of RCOO by neutralizing IBP and NPX through esterification, which reduced the displacement of DP. The competition was also monitored by stopped-flow experiments. While IBP and NPX displaced DP in less than 1 s, the ester derivatives were ineffective. We also observed a higher affinity of negatively charged NSAIDs using DFS as a probe and ultrafiltration experiments. Molecular docking simulations showed an essential salt bridge between the positively charged residues Arg409 and Lys413 with RCOO-, consistent with the experimental findings. We performed a ligand dissociation pathway and corresponding energy analysis by applying molecular dynamics. The dissociation of NPX showed a higher free energy barrier than its ester. Apart from BSA, we conducted some experimental studies with human serum albumin, and similar results were obtained, suggesting a general effect for other mammalian serum albumins. Our findings support that the RCOOH moiety affects not only the mechanism of action and side effects but also the pharmacokinetics of NSAIDs.
Topics: Animals; Cattle; Humans; Anti-Inflammatory Agents, Non-Steroidal; Binding Sites; Carboxylic Acids; Diflunisal; Ibuprofen; Ketoprofen; Ligands; Molecular Docking Simulation; Naproxen; Protein Binding; Serum Albumin, Bovine
PubMed: 38574292
DOI: 10.1021/acs.molpharmaceut.4c00044 -
American Journal of Kidney Diseases :... Mar 2024Hereditary transthyretin amyloidosis (ATTRv) is a rare, progressive, and life-threatening disease caused by misfolded transthyretin (TTR) proteins that aggregate as... (Review)
Review
Hereditary transthyretin amyloidosis (ATTRv) is a rare, progressive, and life-threatening disease caused by misfolded transthyretin (TTR) proteins that aggregate as abnormal amyloid fibrils and accumulate throughout the body. The kidney is one of the main organs affected in amyloid light chain (AL) amyloidosis and ATTRv amyloidosis. The most common clinical presentation is proteinuria, which consists mainly of albumin; this is the first step in the natural history of ATTRv nephropathy. Not all TTR mutations are equal in terms of ATTRv kidney involvement. Kidney involvement in ATTRv itself is difficult to define, given the numerous associated confounding factors. There are several treatments available to treat ATTRv, including orthotopic liver transplant (OLT), which is the classic treatment for ATTRv. However, we should be careful regarding the use of calcineurin inhibitors in the setting of OLT because these can be nephrotoxic. New treatments for amyloidosis may have an impact on kidney function, including drugs that target specific pathways involved in the disease. Tafamidis and diflunisal, which are TTR stabilizers, patisiran (RNA interference agent), and inotersen (antisense oligonucleotide inhibitor) have been shown to reduce TTR amyloid. Tafamidis and patisiran are medications that have reduced the progression of kidney disease in amyloidosis, but inotersen and diflunisal may damage kidney function.
PubMed: 38484868
DOI: 10.1053/j.ajkd.2024.01.527 -
Drug and Chemical Toxicology Mar 2024In this study, the toxic and teratogenic effects of three commercial drugs and their active ingredients on embryos before and after ozonation were evaluated using the...
In this study, the toxic and teratogenic effects of three commercial drugs and their active ingredients on embryos before and after ozonation were evaluated using the Frog Embryos Teratogenesis Assay- (FETAX). First, the median lethal concentration (LC) and, if data were available, the median effective concentration, teratogenic index and minimum growth inhibitory concentration were determined for each drug substance without ozonation. Then, the active substance amounts of three selected nominal concentrations (LC/2, LC, and LC×2) of each test substance before ozonation were measured by HPLC analysis and the toxicity of these substances was evaluated after 2, 3, 4, and 5 h of ozonation. In addition, degradation products that may occur during ozonation were evaluated by LC-MS analysis. The 96-h LCs of Dolphin-diflunisal, Dichloron-diclofenac sodium, and Apranax-naproxen drug-active substance pairs were determined to be 22.3 and 11.1, 25.7 and 18.7, and 47.8 mg active substance/L and 45.3 mg/L, respectively. According to the FETAX test results, the Dolphin-diflunisal drug-active ingredient pair did not cause growth retardation in exposed embryos. Dichloron-diclofenac sodium and Apranax-naproxen drug-active ingredient pairs were both teratogenic and growth inhibitory. In the second stage of the study, in which the effectiveness of ozonation in eliminating the toxic effects of drugs is evaluated, it is seen that ozonation is partially successful in eliminating the toxic effects of Dolphin-diflunisal and Dichloron-diclofenac sodium pairs, but insufficient for eliminating the effects of the Apranax-naproxen pair.
PubMed: 38465443
DOI: 10.1080/01480545.2024.2324325 -
Revista Espanola de Cardiologia... May 2024
Topics: Humans; Amyloid Neuropathies, Familial; Diflunisal; Male; Cardiomyopathies; Female; Aged; Treatment Outcome; Middle Aged
PubMed: 38325700
DOI: 10.1016/j.rec.2023.10.016 -
Molecules (Basel, Switzerland) Jan 2024The small-molecule iododiflunisal (IDIF) is a transthyretin (TTR) tetramer stabilizer and acts as a chaperone of the TTR-Amyloid beta interaction. Oral administration of...
The small-molecule iododiflunisal (IDIF) is a transthyretin (TTR) tetramer stabilizer and acts as a chaperone of the TTR-Amyloid beta interaction. Oral administration of IDIF improves Alzheimer's Disease (AD)-like pathology in mice, although the mechanism of action and pharmacokinetics remain unknown. Radiolabeling IDIF with positron or gamma emitters may aid in the in vivo evaluation of IDIF using non-invasive nuclear imaging techniques. In this work, we report an isotopic exchange reaction to obtain IDIF radiolabeled with F. [F/F]exchange reaction over IDIF in dimethyl sulfoxide at 160 °C resulted in the formation of [F]IDIF in 7 ± 3% radiochemical yield in a 20 min reaction time, with a final radiochemical purity of >99%. Biodistribution studies after intravenous administration of [F]IDIF in wild-type mice using positron emission tomography (PET) imaging showed capacity to cross the blood-brain barrier (ca. 1% of injected dose per gram of tissue in the brain at t > 10 min post administration), rapid accumulation in the liver, long circulation time, and progressive elimination via urine. Our results open opportunities for future studies in larger animal species or human subjects.
Topics: Humans; Animals; Mice; Pharmaceutical Preparations; Tissue Distribution; Alzheimer Disease; Prealbumin; Amyloid beta-Peptides; Excipients; Diflunisal
PubMed: 38257401
DOI: 10.3390/molecules29020488 -
The Journal of Physical Chemistry. B Nov 2023Understanding the interaction between the drug:carrier complex and protein is essential for the development of a new drug-delivery system. However, the majority of...
Understanding the interaction between the drug:carrier complex and protein is essential for the development of a new drug-delivery system. However, the majority of reports are based on an understanding of interactions between the drug and protein. Here, we present our findings on the interaction of the anti-inflammatory drug diflunisal with the drug carrier cyclodextrin (CD) and the protein lysozyme, utilizing steady-state and time-resolved fluorescence spectroscopy. Our findings reveal a different pattern of molecular interaction between the inclusion complex of β-CD (β-CD) or hydroxypropyl-β-CD (HP-β-CD) (as the host) and diflunisal (as the guest) in the presence of protein lysozyme. The quantum yield for the 1:2 guest:host complex is twice that of the 1:1 guest:host complex, indicating a more stable hydrophobic microenvironment created in the 1:2 complex. Consequently, the nonradiative decay pathway is significantly reduced. The interaction is characterized by ultrafast solvation dynamics and time-resolved fluorescence resonance energy transfer. The solvation dynamics of the lysozyme becomes 10% faster under the condition of binding with the drug, indicating a negligible change in the polar environment after binding. In addition, the fluorescence lifetime of diflunisal (acceptor) is increased by 50% in the presence of the lysozyme (donor), which indicates that the drug molecule is bound to the binding pocket on the surface of the protein, and the average distance between active tryptophan in the hydrophobic region and diflunisal is calculated to be approximately 50 Å. Excitation and emission matrix spectroscopy reveals that the tryptophan emission increases 3-5 times in the presence of both diflunisal and CD. This indicates that the tryptophan of lysozyme may be present in a more hydrophobic environment in the presence of both diflunisal and CD. Our observations on the interaction of diflunisal with β-CD and lysozyme are well supported by molecular dynamics simulation. Results from this study may have an impact on the development of a better drug-delivery system in the future. It also reveals a fundamental molecular mechanism of interaction of the drug-carrier complex with the protein.
Topics: Diflunisal; Cyclodextrins; Tryptophan; Muramidase; Spectrometry, Fluorescence; 2-Hydroxypropyl-beta-cyclodextrin; Pharmaceutical Preparations
PubMed: 37917720
DOI: 10.1021/acs.jpcb.3c04295 -
Analytical Sciences : the International... Jan 2024NMR screening methods based on F spin-spin relaxation time (F-T) were applied to fluorinated compounds bound to human serum albumin. Diflunisal and fleroxacin (the...
NMR screening methods based on F spin-spin relaxation time (F-T) were applied to fluorinated compounds bound to human serum albumin. Diflunisal and fleroxacin (the fluorinated compounds) contain two and three fluorine atoms per molecule, respectively, and are suitable as the model system for F NMR analysis. It was shown that F-T was more sensitive in monitoring the binding affinity to the target protein than F spin-lattice relaxation time (F-T). The comparisons of F signal intensities acquired at different echo times using F-T pulse sequence were also shown to be an effective means of assessing complex formation for fluorinated compounds.
Topics: Humans; Magnetic Resonance Spectroscopy; Proteins; Fluorine; Serum Albumin, Human; Fleroxacin
PubMed: 37838626
DOI: 10.1007/s44211-023-00435-0 -
ESC Heart Failure Feb 2024We conducted a presentation on an 84-year-old male patient who has been diagnosed with TTRA81V (p. TTRA101V) hereditary transthyretin cardiac amyloidosis (hATTR-CM). In...
AIMS
We conducted a presentation on an 84-year-old male patient who has been diagnosed with TTRA81V (p. TTRA101V) hereditary transthyretin cardiac amyloidosis (hATTR-CM). In order to establish its pathogenicity, we extensively investigated the biochemical and biophysical properties of the condition.
METHODS AND RESULTS
Transthyretin amyloid cardiomyopathy (ATTR-CM) is an increasingly acknowledged progressive infiltrative cardiomyopathy that leads to heart failure and potentially fatal arrhythmias. Gaining a comprehensive understanding of the biochemical and biophysical characteristics of genetically mutated TTR proteins serves as the fundamental cornerstone for delivering precise medical care to individuals affected by ATTR. Laboratory assessments indicated a brain natriuretic peptide of 200.12 ng/L (normal range: 0-100 ng/L) and high-sensitivity cardiac troponin I of 0.189 μg/L (normal range: 0-0.1 μg/L). Echocardiography identified left atrial enlargement, symmetrical left ventricular hypertrophy (16 mm septal and 16 mm posterior wall), and a left ventricular ejection fraction of 56%. Cardiac-enhanced magnetic resonance imaging revealed subendocardial late gadolinium enhancement. Tc-99m-PYP nuclear scintigraphy confirmed grade 3 myocardial uptake, showing an increased heart-to-contralateral ratio (H/CL = 2.33). Genetic testing revealed a heterozygous missense mutation in the TTR gene (c.302C>T), resulting in an alanine-to-valine residue change (p. Ala81Val, following the first 20 residues of signal sequence nomenclature). Biochemical analysis of this variant displayed compromised kinetic stability in both the TTRA81V:WT (wild-type) heterozygote protein (half-life, t = 21 h) and the TTRA81V homozygote protein (t = 17.5 h). The kinetic stability fell between that of the TTRWT (t = 42 h) and the early-onset TTRL55P mutation (t = 4.4 h), indicating the patient's late-onset condition. Kinetic stabilizers (Tafamidis, Diflunisal, and AG10) all exhibited the capacity to inhibit TTRA81V acid- and mechanical force-induced fibril formation, albeit less effectively than with TTRWT. Chromatographic assessment of the patient's serum TTR tetramers indicated a slightly lower concentration (3.0 μM) before oral administration of Tafamidis compared with the normal range (3.6-7.2 μM).
CONCLUSIONS
We identified a patient with hATTR-CM who possesses a rare TTRA81V mutation solely associated with cardiac complications. The slightly reduced kinetic stability of this mutation indicates its late-onset nature and contributes to the gradual progression of the disease.
Topics: Male; Humans; Aged, 80 and over; Prealbumin; Contrast Media; Stroke Volume; Gadolinium; Ventricular Function, Left; Amyloid Neuropathies, Familial; Cardiomyopathies; Mutation
PubMed: 37827496
DOI: 10.1002/ehf2.14543