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Proceedings of the National Academy of... Jul 2018Transthyretin (TTR) is a globular tetrameric transport protein in plasma. Nearly 140 single amino acid substitutions in TTR cause life-threatening amyloid disease. We...
Transthyretin (TTR) is a globular tetrameric transport protein in plasma. Nearly 140 single amino acid substitutions in TTR cause life-threatening amyloid disease. We report a one-of-a-kind pathological variant featuring a Glu51, Ser52 duplication mutation (Glu51_Ser52dup). The proband, heterozygous for the mutation, exhibited an unusually aggressive amyloidosis that was refractory to treatment with the small-molecule drug diflunisal. To understand the poor treatment response and expand therapeutic options, we explored the structure and stability of recombinant Glu51_Ser52dup. The duplication did not alter the protein secondary or tertiary structure but decreased the stability of the TTR monomer and tetramer. Diflunisal, which bound with near-micromolar affinity, partially restored tetramer stability. The duplication had no significant effect on the free energy and enthalpy of diflunisal binding, and hence on the drug-protein interactions. However, the duplication induced tryptic digestion of TTR at near-physiological conditions, releasing a C-terminal fragment 49-129 that formed amyloid fibrils under conditions in which the full-length protein did not. Such C-terminal fragments, along with the full-length TTR, comprise amyloid deposits in vivo. Bioinformatics and structural analyses suggested that increased disorder in the surface loop, which contains the Glu51_Ser52dup duplication, not only helped generate amyloid-forming fragments but also decreased structural protection in the amyloidogenic residue segment 25-34, promoting misfolding of the full-length protein. Our studies of a unique duplication mutation explain its diflunisal-resistant nature, identify misfolding pathways for amyloidogenic TTR variants, and provide therapeutic targets to inhibit amyloid fibril formation by variant TTR.
Topics: Amyloid; Amyloid Neuropathies, Familial; Diflunisal; Drug Resistance; Female; Humans; Male; Models, Molecular; Mutation; Prealbumin; Protein Structure, Secondary
PubMed: 29941560
DOI: 10.1073/pnas.1802977115 -
International Journal of Molecular... Mar 2023One the main research goals of bioinorganic chemists is the synthesis of novel coordination compounds possessing biological potency. Within this context, three novel...
One the main research goals of bioinorganic chemists is the synthesis of novel coordination compounds possessing biological potency. Within this context, three novel iron(III) complexes with the non-steroidal anti-inflammatory drugs diflunisal and diclofenac in the presence or absence of the nitrogen donors 1,10-phenanthroline or pyridine were isolated and characterized by diverse techniques. The complexes were evaluated for their ability to scavenge in vitro free radicals such as hydroxyl, 1,1-diphenyl-2-picrylhydrazyl and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radicals, revealing their selective potency towards hydroxyl radicals. The in vitro inhibitory activity of the complexes towards the enzymes acetylcholinesterase and butyrylcholinesterase was evaluated, and their potential to achieve neuroprotection appeared promising. The interaction of the complexes with calf-thymus DNA was examined in vitro, revealing their ability to intercalate in-between DNA nucleobases. The affinity of the complexes for serum albumins was evaluated in vitro and revealed their tight and reversible binding.
Topics: Antioxidants; Ferric Compounds; Cholinergic Antagonists; Butyrylcholinesterase; Acetylcholinesterase; Coordination Complexes; Anti-Inflammatory Agents, Non-Steroidal; DNA
PubMed: 37047364
DOI: 10.3390/ijms24076391 -
Heart Failure Reviews Mar 2015Transthyretin-cardiac amyloidoses (ATTR-CA) are an underdiagnosed but increasingly recognized cause of heart failure. Extracellular deposition of fibrillary proteins... (Review)
Review
Transthyretin-cardiac amyloidoses (ATTR-CA) are an underdiagnosed but increasingly recognized cause of heart failure. Extracellular deposition of fibrillary proteins into tissues due to a variety of inherited transthyretin mutations in ATTRm or due to advanced age in ATTRwt eventually leads to organ failure. In the heart, amyloid deposition causes diastolic dysfunction, restrictive cardiomyopathy with progressive loss of systolic function, arrhythmias, and heart failure. While traditional treatments have consisted of conventional heart failure management and supportive care for systemic symptoms, numerous disease-modifying therapies have emerged over the past decade. From organ transplantation to transthyretin stabilizers (diflunisal, tafamidis, AG-1), TTR silencers (ALN-ATTR02, ISIS-TTR(Rx)), and degraders of amyloid fibrils (doxycycline/TUDCA), the potential for effective transthyretin amyloid therapy is greater now than ever before. In light of these multiple agents under investigation in human clinical trials, clinicians should be familiar with the systemic cardiac amyloidoses, their differing pathophysiology, natural histories, and unique treatment strategies.
Topics: Amyloid Neuropathies, Familial; Benzoxazoles; Biomarkers; Cardiomyopathies; Cyclooxygenase Inhibitors; Defibrillators, Implantable; Diflunisal; Doxycycline; Heart Failure; Humans; Oligonucleotides, Antisense; Organ Transplantation; Pacemaker, Artificial; RNA, Small Interfering
PubMed: 25408161
DOI: 10.1007/s10741-014-9462-7 -
Annals of the Rheumatic Diseases Apr 1982Thirty-seven patients with chronic back pain were entered into a randomised, 3-way, double-blind, cross-over comparison of naproxen sodium 550 mg twice daily, diflunisal... (Clinical Trial)
Clinical Trial Comparative Study Randomized Controlled Trial
Thirty-seven patients with chronic back pain were entered into a randomised, 3-way, double-blind, cross-over comparison of naproxen sodium 550 mg twice daily, diflunisal 500 mg twice daily, and placebo. Each treatment was given for 14 days after a preadmission wash-out week during which only paracetamol was allowed. Patients were assessed on admission and at the end of each treatment with respect to global pain, night pain, pain on movement, and pain on standing. Both visual analogue scales and simple descriptive scales were used to measure pain. Side effects were elicited by a nonleading question. Both methods of pain measurement gave similar results and were highly correlated. Naproxen sodium was superior to placebo in relieving global pain and depending on the method of measurement, in relieving night pain and pain on movement. Diflunisal showed no significant differences from placebo. Side effects were similar on all 3 treatments. The final preference of the patients was significantly in favour of the active treatments.
Topics: Adult; Aged; Back Pain; Clinical Trials as Topic; Diflunisal; Double-Blind Method; Female; Humans; Male; Middle Aged; Naproxen; Random Allocation; Salicylates
PubMed: 6462116
DOI: 10.1136/ard.41.2.129 -
International Journal of Cardiology.... Dec 2015Mutated transthyretin-associated (ATTRm) amyloidosis with heart failure is associated with decreased longitudinal left ventricular (LV) myocardial contraction, as...
Left ventricular deformation and torsion assessed by speckle-tracking echocardiography in patients with mutated transthyretin-associated cardiac amyloidosis and the effect of diflunisal on myocardial function.
BACKGROUND
Mutated transthyretin-associated (ATTRm) amyloidosis with heart failure is associated with decreased longitudinal left ventricular (LV) myocardial contraction, as measured by strain Doppler echocardiography. We sought to clarify whether speckle-tracking echocardiography (STE) would provide useful information in patients with ATTRm cardiac amyloidosis.
METHODS
One hundred twenty-three consecutive patients with ATTRm amyloidosis were divided into 3 groups. Group 1 had no evidence of cardiac involvement (n = 47), group 2 had heart involvement but no congestive heart failure (CHF) and/or serum brain natriuretic peptide (BNP) levels < 100 pg/mL (n = 35), and group 3 had heart involvement and CHF and/or serum BNP levels ≥ 100 pg/mL (n = 41). All patients underwent standard 2-dimensional (2D), Doppler echo, and STE.
RESULTS
By standard 2D and Doppler echo, differences in parameters were only apparent between group 3 and groups 1 and 2. Global circumferential strains by STE at each LV level and LV torsion were different between group 1 and groups 2 and 3, but not between group 2 and group 3. In contrast, global longitudinal LV strain showed significant intergroup differences (- 17.3 ± 2.3%, - 13.3 ± 2.3%, - 9.9 ± 3.3% for groups 1 to 3, respectively, < 0.0001). Radial strain also showed significant intergroup differences for each basal LV segment. Among 41 patients who could have been followed up after 1 year, 34 patients with diflunisal treatment had shown improvement in apical rotation and torsion without deterioration in multidirectional strains.
CONCLUSION
ATTRm cardiac amyloidosis is characterized by progressive impairment in longitudinal and basal LV radial function when global circumferential shortening and torsion remain unchanged.
PubMed: 28785698
DOI: 10.1016/j.ijcha.2015.07.010 -
Degenerative Neurological and... 2012Over the last decade, new medical treatment modalities have emerged based on increased insights into amyloid formation. With the increased possibilities for treatment of... (Review)
Review
Over the last decade, new medical treatment modalities have emerged based on increased insights into amyloid formation. With the increased possibilities for treatment of amyloidosis caused by transthyretin (TTR) amyloid deposits comes the need for diagnostic procedures for early diagnosis and better tools to follow disease progression. This is of particular importance in clinical trials evaluating the efficacy of new treatments. Until recently, the treatment of TTR amyloidosis (ATTR) was based solely on liver transplantation, a procedure that has halted disease progression in many patients. Liver transplantation has been especially effective in patients under the age of 50 years carrying the TTR V30M mutation, whereas the outcome of the procedure has been variable for others, particularly elderly male patients and those carrying a non-V30M mutation. This review concentrates on new insights derived from our center's experience with liver transplantation, how to implement this experience in evaluation of new treatment modalities for ATTR, and how to facilitate early diagnosis of neuropathy with easily available diagnostic tools. Attention has focused on manifestations of the disease that involve the heart and the peripheral nervous system; change in peripheral nerve function has been the primary endpoint in two controlled clinical trials, one finished and one ongoing. New insights into the amyloid formation process and the lessons learned from liver transplantation give the opportunity to design potentially effective treatment modalities for ATTR. It appears reasonable to suspect that a combination of different treatment modalities may be required to treat the disease, and that different treatment regimes will be designed according to the phenotype of the disease. For the patients and their relatives there is now a solid foundation for optimism, with prospects of several effective medical treatment possibilities within the coming decade.
PubMed: 30890882
DOI: 10.2147/DNND.S24652 -
International Journal of Nanomedicine 2021Rheumatoid arthritis is an autoimmune disorder that directly affects joints. However, other body organs including heart, eyes, skin, blood vessels and lungs may also be...
PURPOSE
Rheumatoid arthritis is an autoimmune disorder that directly affects joints. However, other body organs including heart, eyes, skin, blood vessels and lungs may also be affected. The purpose of this study was to design and evaluate a nanoemulgel formulation of diflunisal (DIF) and solubility enhanced diflunisal (DIF-IC) for enhanced topical anti-inflammatory activity.
METHODOLOGY
Nanoemulsion formulations of both DIF and DIF-IC were prepared and incorporated in three different gelling agents, namely carboxymethylcellulose sodium (CMC-Na), sodium alginate (Na-ALG) and xanthan gum (XG). All the formulations were evaluated in term of particle size, pH, conductivity, viscosity, zeta potential and in vitro drug release. The formulation 2 (NE2) of both DIF and DIF-IC which expressed optimum release and satisfactory physicochemical properties was incorporated with gelling agents to produce final nanoemulgel formulations. The optimized nanoemulgel formulation was subjected to three different in vivo anti-inflammatory models including carrageenan-induced paw edema model, histamine-induced paw edema model and formalin-induced paw edema model.
RESULTS
DIF-IC-loaded nanoemulgel formulations yielded significantly enhanced in vitro skin permeation than DIF-loaded nanoemulgel. The nanoemulgel formulation of DIF-IC formulated with XG produced improved in vivo anti-inflammatory activity.
CONCLUSION
It was recommended that DIF-IC-based nanoemulgel formulation prepared with XG could be a better option for effective topical treatment of inflammatory conditions.
Topics: Administration, Topical; Animals; Anti-Inflammatory Agents; Carrageenan; Diflunisal; Disease Models, Animal; Drug Compounding; Drug Delivery Systems; Drug Liberation; Edema; Electric Conductivity; Emulsions; Hydrogen-Ion Concentration; Male; Nanogels; Particle Size; Permeability; Phase Transition; Polyethylene Glycols; Polyethyleneimine; Rats; Skin; Skin Absorption; Solubility; Surface-Active Agents; Viscosity
PubMed: 33654396
DOI: 10.2147/IJN.S294653 -
Frontiers in Microbiology 2015Bacterial infection remains one of the leading causes of death worldwide, and the options for treating such infections are decreasing, due the rise of...
Bacterial infection remains one of the leading causes of death worldwide, and the options for treating such infections are decreasing, due the rise of antibiotic-resistant bacteria. The pharmaceutical industry has produced few new types of antibiotics in more than a decade. Researchers are taking several approaches toward developing new classes of antibiotics, including (1) focusing on new targets and processes, such as bacterial cell-cell communication that upregulates virulence; (2) designing inhibitors of bacterial resistance, such as blockers of multidrug efflux pumps; and (3) using alternative antimicrobials such as bacteriophages. In addition, the strategy of finding new uses for existing drugs is beginning to produce results: antibacterial properties have been discovered for existing anticancer, antifungal, anthelmintic, and anti-inflammatory drugs. In this review, we discuss the antimicrobial properties of gallium compounds, 5-fluorouracil, ciclopirox, diflunisal, and some other FDA-approved drugs and argue that their repurposing for the treatment of bacterial infections, including those that are multidrug resistant, is a feasible strategy.
PubMed: 25914685
DOI: 10.3389/fmicb.2015.00282 -
Neurology and Therapy Dec 2020Little is known about the burden of hereditary transthyretin (ATTRv) amyloidosis, a genetic, progressive, and fatal disease caused by extracellular deposition of...
INTRODUCTION
Little is known about the burden of hereditary transthyretin (ATTRv) amyloidosis, a genetic, progressive, and fatal disease caused by extracellular deposition of transthyretin amyloid fibrils. The study's aim was to estimate costs and disease burden associated with ATTRv amyloidosis in a real-world setting.
METHODS
Using IBM MarketScan Commercial and Medicare Supplemental data, we identified patients at least 18 years of age with newly diagnosed ATTRv amyloidosis. Diagnosis required at least one medical claim with relevant diagnosis code (International Classification of Diseases, 9th Revision, Clinical Modification [ICD-9-CM] 277.30-.31, 277.39; ICD-10-CM E85.0-.4, E85.89, E85.9) between January 1, 2014 and December 31, 2016, and at least one additional criterion occurring during study period (2013-2017): at least 15 days diflunisal use without more than a 30-day gap; liver transplant; or claim with codes E85.1 or E85.2. First diagnosis date was study index. Continuous enrollment 1-year pre-index (baseline) and post-index (follow-up) was required. Patients with baseline amyloidosis diagnosis were excluded. Outcomes of interest were comorbidities and 1-year follow-up healthcare utilization and costs (also reported quarterly).
RESULTS
Among 185 qualifying patients, mean age was 59.2 years (standard deviation 15.2), 54.1% were female, and baseline Charlson comorbidity index was 2.2 (2.5). Neuropathy (30.3%), diabetes (27.0%), and cardiovascular-related comorbidities, including dyspnea (25.9%) and congestive heart failure (21.6%), were common during follow-up. Nearly a quarter of patients (24.9%) were hospitalized during follow-up. Most hospitalizations and emergency department visits occurred in the first quarter post-diagnosis (18.9%, 17.8%, respectively) and dropped in subsequent quarters. The annual mean total cost was $64,066, with inpatient services contributing the majority of the expenses ($34,461), followed by outpatient ($23,853), and then pharmacy ($5752). As with utilization, costs were highest in the first quarter post-diagnosis and dropped in subsequent quarters.
CONCLUSION
Patients newly diagnosed with ATTRv amyloidosis have substantial healthcare utilization and costs in the first year, primarily the initial months, post-diagnosis. Further research should examine later costs associated with disease progression and end-of-life care.
PubMed: 32451849
DOI: 10.1007/s40120-020-00194-4 -
The American Journal of Case Reports Nov 2016BACKGROUND Amyloidosis is a protein conformational disorder characterized by extracellular deposition of amyloid fibrils in extracellular tissue. Lung involvement is...
BACKGROUND Amyloidosis is a protein conformational disorder characterized by extracellular deposition of amyloid fibrils in extracellular tissue. Lung involvement is most commonly caused by secondary AL amyloidosis. The familial autosomal-dominant senile transthyretin (ATTR) disease manifests mainly as polyneuropathy and restrictive cardiomyopathy denoting the name familial amyloidotic polyneuropathy (FAP). Rarely, this form manifests with clinical and radiologically relevant respiratory tract symptoms and lung involvement. CASE REPORT A 51-year-old male former smoker presented with progressive lower-extremity weakness of several months' duration. He was ultimately diagnosed with chronic demyelinating polyneuropathy and treated with intravenous immunoglobulin therapy. Subsequently, he was admitted with heart failure symptoms and pulmonary infiltrates and his echocardiogram showed a 'myocardial speckled pattern', prompting an endomyocardial biopsy, which showed transthyretin amyloid deposition. He was started on diflunisal. Additionally, serial radiographic imaging of his chest over 3 different admissions for cough, dyspnea, hypoxemia, and lethargy demonstrated recurrent pulmonary infiltrates. A fiberoptic bronchoscopy with trans-bronchial biopsies revealed amyloid deposition in the lung tissue. CONCLUSIONS The clinical presentation of recurrent or persistent pulmonary symptoms and fleeting infiltrates on imaging in a patient with familial amyloidotic polyneuropathy is not common; when present, it should raise the suspicion of respiratory tract involvement.
Topics: Amyloidosis, Familial; Bronchoalveolar Lavage Fluid; Bronchoscopy; Diagnosis, Differential; Humans; Lung; Lung Diseases; Male; Middle Aged; Radiography, Thoracic; Tomography, X-Ray Computed
PubMed: 27872470
DOI: 10.12659/ajcr.900682