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2.
ACR Open Rheumatol ; 2021 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-33605563

RESUMO

OBJECTIVE: The increase in cardiovascular events (CVEs) in systemic lupus erythematosus (SLE) is not fully explained by traditional risk factors. We previously identified four biomarkers (proinflammatory high-density lipoprotein, leptin, soluble TNF-like weak inducer of apoptosis (sTWEAK), and homocysteine) that we combined with age and diabetes to create the predictors of risk for elevated flares, damage progression, and increased cardiovascular diseasein patients with SLE (PREDICTS) risk profile. PREDICTS more accurately identified patients with SLE at risk for progression of subclinical atherosclerosis than any individual variable. We examined whether PREDICTS can also identify patients with SLE at risk for future CVEs. METHODS: A total of 342 patients with SLE and 155 matched control subjects participated in this longitudinal prospective study. A high PREDICTS score was defined as three or more predictors or diabetes + one or more predictor. The biomarkers were measured at baseline using published methods. All major adverse CVEs (MACEs) were confirmed by medical record review. RESULTS: During 116 months of follow-up, 5% of patients with SLE died, 12% had a cerebrovascular event, and 5% had a cardiac event. Overall, 20% of patients with lupus experienced any new MACE compared with 5% of control subjects (P < 0.0001). More patients with SLE with a new MACE had high PREDICTS score at baseline (77%) versus patients with no new events (34%) (P < 0.0001). High baseline PREDICTS score also associated with cerebrovascular (P < 0.0001) and cardiac events (P < 0.0001) in SLE. Using Cox regression, a baseline high PREDICTS score associated with a 3.7-fold increased hazard ratio (HR) for a new MACE (P < 0.0001) in SLE. Hypertension (HR = 2.1; P = 0.006) was also a risk. CONCLUSION: A high PREDICTS score and hypertension confer increased risk for new MACEs in patients with SLE.

3.
Artigo em Inglês | MEDLINE | ID: mdl-33547784

RESUMO

OBJECTIVES: Atacicept reduced SLE disease activity in the Phase IIb ADDRESS II study, particularly in patients with high disease activity (HDA; SLEDAI-2K ≥10) at screening. We assessed long-term safety and efficacy of atacicept in the long-term extension (LTE) of ADDRESS II. METHODS: In the 24-week, randomised, double-blind, placebo-controlled ADDRESS II study, patients received weekly atacicept (75 or 150 mg) or placebo. Atacicept was continued at the same dose in atacicept-treated patients in the LTE; placebo-treated patients switched to atacicept 150 mg. Long-term safety was the primary end point. Secondary endpoints included SLE responder index (SRI)-4 and SRI-6 response rates and flares. RESULTS: 253 patients entered the ADDRESS II LTE; 88 received atacicept 150 mg, 82 atacicept 75 mg and 83 placebo/atacicept 150 mg. Median active treatment duration in the LTE was 83.8 weeks. Frequencies of treatment-emergent adverse events (TEAEs) were similar across groups (90.4-93.2%). 12.5%, 14.6% and 21.7% of patients in the atacicept 150 mg, atacicept 75 mg and placebo/atacicept 150 mg groups reported serious TEAEs during the treatment period. The proportions of patients with TEAEs leading to discontinuation were 5.7%, 4.9% and 10.8%, respectively. SRI-4 and SRI-6 response rates were maintained with atacicept in the modified intent-to-treat and HDA populations and those on continuous 150 mg had a reduced risk of first severe flare and longer time to first severe flare vs those who initially received placebo. CONCLUSION: Long-term treatment with atacicept 150 mg in SLE patients had an acceptable safety profile, with durable efficacy. CLINICAL TRIAL REGISTRATION NUMBER: NCT02070978.

4.
Artigo em Inglês | MEDLINE | ID: mdl-33555325

RESUMO

OBJECTIVES: Vitamin D (25(OH)D) deficiency and metabolic syndrome (MetS) may both contribute to increased cardiovascular risk in systemic lupus erythematosus (SLE). We aimed to examine the association of demographic factors, SLE phenotype, therapy and vitamin D levels with MetS and insulin resistance. METHODS: The Systemic Lupus International Collaborating Clinics (SLICC) enrolled patients recently diagnosed with SLE (<15 months) from 33 centres across 11 countries from 2000. Clinical, laboratory and therapeutic data were collected. Vitamin D level was defined according to tertiles based on distribution across this cohort, which were set at T1 (10-36 nmol/l), T2 (37-60 nmol/l) and T3 (61-174 nmol/l). MetS was defined according to the 2009 consensus statement from the International Diabetes Federation. Insulin resistance was determined using the HOMA-IR model. Linear and logistic regressions were used to assess the association of variables with vitamin D levels. RESULTS: Of the 1847 patients, 1163 (63%) had vitamin D measured and 398 (34.2%) subjects were in the lowest 25(OH)D tertile. MetS was present in 286 of 860 (33%) patients whose status could be determined. Patients with lower 25(OH)D were more likely to have MetS and higher HOMA-IR. The MetS components, hypertension, hypertriglyceridemia and decreased HDL were all significantly associated with lower 25(OH)D. Increased average glucocorticoid exposure was associated with higher insulin resistance. CONCLUSIONS: MetS and insulin resistance are associated with lower vitamin D in patients with SLE. Further studies could determine whether vitamin D repletion confers better control of these cardiovascular risk factors and improve long-term outcomes in SLE.

5.
ACR Open Rheumatol ; 2021 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-33538130

RESUMO

OBJECTIVE: To evaluate the usefulness of biomarkers to predict the evolution of patients suspected of systemic lupus erythematosus (SLE), designated as probable SLE (pSLE), into classifiable SLE according to the American College of Rheumatology (ACR) classification criteria. METHODS: Patients suspected of SLE were enrolled by lupus experts if they fulfilled three ACR criteria for SLE and were followed for approximately 1-3 years to evaluate transition into ACR-classifiable SLE. Individual cell-bound complement activation products (CB-CAPs), serum complement proteins (C3 and C4), and autoantibodies were measured by flow cytometry, turbidimetry, and enzyme-linked immunosorbent assay, respectively. Blood levels of hydroxychloroquine (HCQ) were measured by mass spectrometry. A multianalyte assay panel (MAP), which includes CB-CAPs, was also evaluated. A MAP of greater than 0.8 reflected the optimal cutoff for transition to SLE. Time to fulfillment of ACR criteria was evaluated by Kaplan-Meier analysis and Cox proportional hazards model. RESULTS: Of the 92 patients with pSLE enrolled, 74 had one or two follow-up visits 9-35 months after enrollment for a total of 128 follow-up visits. Overall, 28 patients with pSLE (30.4%) transitioned to ACR-classifiable SLE, including 16 (57%) in the first year and 12 (43%) afterwards. A MAP score of greater than 0.8 at enrollment predicted transition to classifiable SLE during the follow-up period (hazard ratio = 2.72; P = 0.012), whereas individual biomarkers or fulfillment of Systemic Lupus International Collaborating Clinics criteria did not. HCQ therapy was not associated with the prevention of transition to SLE. CONCLUSION: Approximately one-third of patients with pSLE transitioned within the study period. MAP of greater than 0.8 predicted disease evolution into classifiable SLE.

6.
Cell Death Differ ; 2020 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-33323945

RESUMO

Alterations in the metabolism of iron and its accumulation in the substantia nigra pars compacta accompany the pathogenesis of Parkinson's disease (PD). Changes in iron homeostasis also occur during aging, which constitutes a PD major risk factor. As such, mitigation of iron overload via chelation strategies has been considered a plausible disease modifying approach. Iron chelation, however, is imperfect because of general undesired side effects and lack of specificity; more effective approaches would rely on targeting distinctive pathways responsible for iron overload in brain regions relevant to PD and, in particular, the substantia nigra. We have previously demonstrated that the Transferrin/Transferrin Receptor 2 (TfR2) iron import mechanism functions in nigral dopaminergic neurons, is perturbed in PD models and patients, and therefore constitutes a potential therapeutic target to halt iron accumulation. To validate this hypothesis, we generated mice with targeted deletion of TfR2 in dopaminergic neurons. In these animals, we modeled PD with multiple approaches, based either on neurotoxin exposure or alpha-synuclein proteotoxic mechanisms. We found that TfR2 deletion can provide neuroprotection against dopaminergic degeneration, and against PD- and aging-related iron overload. The effects, however, were significantly more pronounced in females rather than in males. Our data indicate that the TfR2 iron import pathway represents an amenable strategy to hamper PD progression. Data also suggest, however, that therapeutic strategies targeting TfR2 should consider a potential sexual dimorphism in neuroprotective response.

7.
Artigo em Inglês | MEDLINE | ID: mdl-33152181

RESUMO

OBJECTIVE: The Systemic Lupus International Collaborating Clinics (SLICC) frailty index (FI) predicts mortality and damage accrual in SLE, but its association with hospitalizations has not been described. We estimated the association of baseline SLICC-FI values with future hospitalizations in the SLICC inception cohort. METHODS: Baseline SLICC-FI scores were calculated. The number and duration of inpatient hospitalizations during follow-up were recorded. Negative binomial regression was used to estimate the association between baseline SLICC-FI values and the rate of hospitalizations per patient-year of follow-up. Linear regression was used to estimate the association of baseline SLICC-FI scores with the proportion of follow-up time spent in hospital. Multivariable models were adjusted for relevant baseline characteristics. RESULTS: The 1549 SLE patients eligible for this analysis were mostly female (88.7%) with mean (SD) age 35.7 (13.3) years and median (IQR) disease duration 1.2 (0.9-1.5) years at baseline. Mean (SD) baseline SLICC-FI was 0.17 (0.08). During mean (SD) follow-up of 7.2 (3.7) years, 614 patients (39.6%) experienced 1570 hospitalizations. Higher baseline SLICC-FI values (per 0.05 increment) were associated with more frequent hospitalizations during follow-up (Incidence Rate Ratio 1.21; 95%CI 1.13-1.30), adjusting for baseline age, sex, corticosteroid use, immunosuppressive use, ethnicity/location, SLE disease activity index 2000 (SLEDAI-2K), SLICC/ACR damage index (SDI), and disease duration. Among patients with ≥1 hospitalization, higher baseline SLICC-FI values predicted a greater proportion of follow-up time spent hospitalized (Relative Rate 1.09; 95%CI 1.02-1.16). CONCLUSION: The SLICC-FI predicts future hospitalizations among incident SLE patients, further supporting the SLICC-FI as a valid health measure in SLE.

8.
Front Immunol ; 11: 554725, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33072095

RESUMO

Systemic Lupus Erythematosus (SLE) is a chronic inflammatory autoimmune disease in which type I interferons (IFN) play a key role. The IFN response can be triggered when oxidized DNA engages the cytosolic DNA sensing platform cGAS-STING, but the repair mechanisms that modulate this process and govern disease progression are unclear. To gain insight into this biology, we interrogated the role of oxyguanine glycosylase 1 (OGG1), which repairs oxidized guanine 8-Oxo-2'-deoxyguanosine (8-OH-dG), in the pristane-induced mouse model of SLE. Ogg1 -/- mice showed increased influx of Ly6Chi monocytes into the peritoneal cavity and enhanced IFN-driven gene expression in response to short-term exposure to pristane. Loss of Ogg1 was associated with increased auto-antibodies (anti-dsDNA and anti-RNP), higher total IgG, and expression of interferon stimulated genes (ISG) to longer exposure to pristane, accompanied by aggravated skin pathology such as hair loss, thicker epidermis, and increased deposition of IgG in skin lesions. Supporting a role for type I IFNs in this model, skin lesions of Ogg1 -/- mice had significantly higher expression of type I IFN genes (Isg15, Irf9, and Ifnb). In keeping with loss of Ogg1 resulting in dysregulated IFN responses, enhanced basal and cGAMP-dependent Ifnb expression was observed in BMDMs from Ogg1 -/- mice. Use of the STING inhibitor, H151, reduced both basal and cGAMP-driven increases, indicating that OGG1 regulates Ifnb expression through the cGAS-STING pathway. Finally, in support for a role for OGG1 in the pathology of cutaneous disease, reduced OGG1 expression in monocytes associated with skin involvement in SLE patients and the expression of OGG1 was significantly lower in lesional skin compared with non-lesional skin in patients with Discoid Lupus. Taken together, these data support an important role for OGG1 in protecting against IFN production and SLE skin disease.

9.
Lupus Sci Med ; 7(1)2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-33037080

RESUMO

OBJECTIVE: To characterise the molecular pathways impacted by the pharmacologic effects of the Janus kinase (JAK) 1 and JAK2 inhibitor baricitinib in SLE. METHODS: In a phase II, 24-week, randomised, placebo-controlled, double-blind study (JAHH), RNA was isolated from whole blood in 274 patients and analysed using Affymetrix HTA2.0 array. Serum cytokines were measured using ultrasensitive quantitative assays. RESULTS: Gene expression profiling demonstrated an elevation of STAT1, STAT2 and multiple interferon (IFN) responsive genes at baseline in patients with SLE. Statistical and gene network analyses demonstrated that baricitinib treatment reduced the mRNA expression of functionally interconnected genes involved in SLE including STAT1-target, STAT2-target and STAT4-target genes and multiple IFN responsive genes. At baseline, serum cytokines IFN-α, IFN-γ, interleukin (IL)-12p40 and IL-6 were measurable and elevated above healthy controls. Treatment with baricitinib significantly decreased serum IL-12p40 and IL-6 cytokine levels at week 12, which persisted through week 24. CONCLUSION: Baricitinib treatment induced significant reduction in the RNA expression of a network of genes associated with the JAK/STAT pathway, cytokine signalling and SLE pathogenesis. Baricitinib consistently reduced serum levels of two key cytokines implicated in SLE pathogenesis, IL-12p40 and IL-6.

10.
J Clin Rheumatol ; 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-33065630

RESUMO

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease that may affect every organ. The multiple pathogenic mechanisms and heterogeneous phenotypes of SLE present unique challenges in the management of this complex disease. This article discusses new SLE therapies from the last 10 years. We will address new information in the realms of lifestyle interventions, antimalarials, nonsteroidal anti-inflammatory drugs, glucocorticoids, immunosuppressive disease modifying antirheumatic drugs, biological therapies, and other modalities as they pertain to SLE.

11.
Artigo em Inglês | MEDLINE | ID: mdl-32813314

RESUMO

OBJECTIVE: To assess cancer risk factors in incident SLE. METHODS: Clinical variables and cancer outcomes were assessed annually among incident SLE patients. Multivariate hazard regression models (over-all risk, and most common cancers) included demographics and time-dependent medications (corticosteroids, antimalarial drugs, immunosuppressants), smoking, and adjusted mean SLE Disease Activity Index-2K. RESULTS: Among 1668 patients (average 9 years follow-up), 65 cancers occurred: 15 breast, 10 non-melanoma skin, seven lung, six hematological, six prostate, five melanoma, three cervical, three renal, two each gastric, head and neck, and thyroid, and one each rectal, sarcoma, thymoma, and uterine cancers. Half of cancers (including all lung cancers) occurred in past/current smokers, versus one-third of patients without cancer. Multivariate analyses indicated over-all cancer risk was related primarily to male sex and older age at SLE diagnosis. In addition, smoking was associated with lung cancer. For breast cancer risk, age was positively and anti-malarial drugs were negatively associated. Anti-malarial drugs and higher disease activity were also negatively associated with non-melanoma skin cancer (NMSC) risk, whereas age and cyclophosphamide were positively associated. Disease activity was associated positively with hematologic and negatively with NMSC risk. CONCLUSIONS: Smoking is a key modifiable risk factor, especially for lung cancer, in SLE. Immunosuppressive medications were not clearly associated with higher risk except for cyclophosphamide and NMSC. Antimalarials were negatively associated with breast cancer and NMSC risk. SLE activity was associated positively with hematologic cancer and negatively with NMSC. Since the absolute number of cancers was small, additional follow-up will help consolidate these findings.

12.
Biosci Rep ; 40(8)2020 08 28.
Artigo em Inglês | MEDLINE | ID: mdl-32766721

RESUMO

Exome sequencing has identified the glyceronephosphate O-acyltransferase (GNPAT) gene as a genetic modifier of iron overload in hereditary hemochromatosis (HH). Subjects with HFE (Homeostatic Iron Regulator) p.C282Y mutations and the GNPAT p.D519G variant had more iron loading compared with subjects without the GNPAT variant. In response to an oral iron challenge, women with GNPAT polymorphisms loaded more iron as compared with women without polymorphisms, reinforcing a role for GNPAT in iron homeostasis. The aim of the present study was to develop and characterize an animal model of disease to further our understanding of genetic modifiers, and in particular the role of GNPAT in iron homeostasis. We generated an Hfe/Gnpat mouse model reminiscent of the patients previously studied and studied these mice for up to 26 weeks. We also examined the effect of dietary iron loading on mice with reduced Gnpat expression. Gnpat heterozygosity in Hfe knockout mice does not play a role in systemic iron homeostasis; Gnpat+/- mice fed a high-iron diet, however, had lower hepatic hepcidin (HAMP) mRNA expression, whereas they have significantly higher serum iron levels and transferrin saturation compared with wildtype (WT) littermates on a similar diet. These results reinforce an independent role of GNPAT in systemic iron homeostasis, reproducing in an animal model, the observations in women with GNPAT polymorphisms subjected to an iron tolerance test.

13.
Blood Cells Mol Dis ; 85: 102463, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32652459

RESUMO

Glyceronephosphate O-acyltransferase (GNPAT) p.D519G (rs11558492) was identified as a genetic modifier correlated with more severe iron overload in hemochromatosis through whole-exome sequencing of HFE p.C282Y homozygotes with extreme iron phenotypes. We studied the prevalence of p.D519G in HFE p.C282Y/p.H63D compound heterozygotes, a genotype associated with iron overload in some patients. Cases were Australian participants with elevated serum ferritin (SF) levels ≥300µg/L (males) and ≥200µg/L (females); subjects whose SF levels were below these cut-offs were designated as controls. Samples were genotyped for GNPAT p.D519G. We compared the allele frequency of the present subjects, with/without elevated SF, to p.D519G frequency in public datasets. GNPAT p.D519G was more prevalent in our cohort of p.C282Y/p.H63D compound heterozygotes with elevated SF (37%) than European public datasets: 1000G 21%, gnomAD 20% and ESP 21%. We conclude that GNPAT p.D519G is associated with elevated SF in Australian HFE p.C282Y/p.H63D compound heterozygotes.

14.
Arthritis Rheumatol ; 72(10): 1734-1740, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32515554

RESUMO

OBJECTIVE: In previous studies, atherosclerotic vascular events (AVEs) were shown to occur in ~10% of patients with systemic lupus erythematosus (SLE). We undertook this study to investigate the annual occurrence and potential risk factors for AVEs in a multinational, multiethnic inception cohort of patients with SLE. METHODS: A large 33-center cohort of SLE patients was followed up yearly between 1999 and 2017. AVEs were attributed to atherosclerosis based on SLE being inactive at the time of the AVE as well as typical atherosclerotic changes observed on imaging or pathology reports and/or evidence of atherosclerosis elsewhere. Analyses included descriptive statistics, rate of AVEs per 1,000 patient-years, and univariable and multivariable relative risk regression models. RESULTS: Of the 1,848 patients enrolled in the cohort, 1,710 had ≥1 follow-up visit after enrollment, for a total of 13,666 patient-years. Of these 1,710 patients, 3.6% had ≥1 AVEs attributed to atherosclerosis, for an event rate of 4.6 per 1,000 patient-years. In multivariable analyses, lower AVE rates were associated with antimalarial treatment (hazard ratio [HR] 0.54 [95% confidence interval (95% CI) 0.32-0.91]), while higher AVE rates were associated with any prior vascular event (HR 4.00 [95% CI 1.55-10.30]) and a body mass index of >40 kg/m2 (HR 2.74 [95% CI 1.04-7.18]). A prior AVE increased the risk of subsequent AVEs (HR 5.42 [95% CI 3.17-9.27], P < 0.001). CONCLUSION: The prevalence of AVEs and the rate of AVE accrual demonstrated in the present study is much lower than that seen in previously published data. This may be related to better control of both the disease activity and classic risk factors.

15.
Lupus Sci Med ; 7(1)2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32371480

RESUMO

OBJECTIVES: To evaluate the association between lupus severity and cell-bound complement activation products (CB-CAPs) or low complement proteins C3 and C4. METHODS: All subjects (n=495) fulfilled the American College of Rheumatology (ACR) classification criteria for SLE. Abnormal CB-CAPs (erythrocyte-bound C4d or B-lymphocyte-bound C4d levels >99th percentile of healthy) and complement proteins C3 and C4 were determined using flow cytometry and turbidimetry, respectively. Lupus severity was estimated using the Lupus Severity Index (LSI). Statistical analysis consisted of multivariable linear regression and groups comparisons. RESULTS: Abnormal CB-CAPs were more prevalent than low complement values irrespective of LSI levels (62% vs 38%, respectively, p<0.0001). LSI was low (median 5.44, IQR: 4.77-6.93) in patients with no complement abnormality, intermediate in patients with abnormal CB-CAPs (median 6.09, IQR: 5.31-8.20) and high in the group presenting with both abnormal CB-CAPs and low C3 and/or C4 (median 7.85, IQR: 5.51-8.37). Odds of immunosuppressant use was higher in subjects with LSI ≥5.95 compared with subjects with LSI <5.95 (1.60 vs 0.53, p<0.0001 for both). Multivariable regression analysis revealed that higher LSI scores associated with abnormal CB-CAPs-but not low C3/C4-after adjusting for younger age, race and longer disease duration (p=0.0001), which were also independent predictors of disease severity (global R2=0.145). CONCLUSION: Abnormalities in complement activation as measured by CB-CAPs are associated with increased LSI.

16.
J Acoust Soc Am ; 147(4): 2271, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32359257

RESUMO

Personal audio refers to the generation of spatially distinct sound zones that allow individuals within a shared space to listen to their own audio material without affecting, or being affected, by others. Recent interest in such systems has focussed on their performance in public spaces where speech privacy is desirable. To achieve this goal, speech is focussed towards the target listener and a masking signal is focussed into the area where the target speech signal could otherwise be overheard. An effective masking signal must substantially reduce the intelligibility in this region without becoming an annoyance to those nearby. To assess these perceptual requirements, listening tests were carried out using two examples of loudspeaker arrays with different spatial aliasing characteristics, to determine the impacts of different masking signal spectra on speech intelligibility and subjective preference. The results of these tests were used, alongside objective and subjective metrics, to form a design specification for private personal audio systems.

17.
Artigo em Inglês | MEDLINE | ID: mdl-32433832

RESUMO

OBJECTIVE: The Systemic Lupus International Collaborating Clinics (SLICC) 2012 SLE classification criteria and the revised American College of Rheumatology (ACR) 1997 criteria are list-based, counting each SLE manifestation equally. We derived a classification rule based on giving variable weights to the SLICC criteria, and compared its performance to the revised ACR 1997, unweighted SLICC 2012 and the newly reported European League Against Rheumatism (EULAR)/ACR 2019 criteria. METHODS: The physician-rated patient scenarios used to develop the SLICC 2012 classification criteria were re-employed to devise a new weighted classification rule using multiple linear regression. The performance of the rule was evaluated on an independent set of expert-diagnosed patient scenarios and compared to the performance of the previously reported classification rules. RESULTS: Weighted SLICC criteria and the EULAR/ACR 2019 criteria had less sensitivity but better specificity compared to the list-based revised ACR 1997 and SLICC 2012 classification criteria. There were no statistically significant differences between any pair of rules with respect to overall agreement with the physician diagnosis. CONCLUSION: The two new weighted classification rules did not perform better than the existing list-based rules in terms of overall agreement on a dataset originally generated to assess the SLICC criteria. Given the added complexity of summing weights, researchers may prefer the unweighted SLICC criteria. However, the performance of a classification rule will always depend on the populations from which the cases and non-cases are derived, and whether the goal is to prioritize sensitivity or specificity.

18.
Hum Genet ; 139(8): 1065-1075, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32248359

RESUMO

Wilson disease (WD) is a genetic disorder of copper metabolism caused by variants in the copper transporting P-type ATPase gene ATP7B. Estimates for WD population prevalence vary with 1 in 30,000 generally quoted. However, some genetic studies have reported much higher prevalence rates. The aim of this study was to estimate the population prevalence of WD and the pathogenicity/penetrance of WD variants by determining the frequency of ATP7B variants in a genomic sequence database. A catalogue of WD-associated ATP7B variants was constructed, and then, frequency information for these was extracted from the gnomAD data set. Pathogenicity of variants was assessed by (a) comparing gnomAD allele frequencies against the number of reports for variants in the WD literature and (b) using variant effect prediction algorithms. 231 WD-associated ATP7B variants were identified in the gnomAD data set, giving an initial estimated population prevalence of around 1 in 2400. After exclusion of WD-associated ATP7B variants with predicted low penetrance, the revised estimate showed a prevalence of around 1 in 20,000, with higher rates in the Asian and Ashkenazi Jewish populations. Reanalysis of other recent genetic studies using our penetrance criteria also predicted lower population prevalences for WD in the UK and France than had been reported. Our results suggest that differences in variant penetrance can explain the discrepancy between reported epidemiological and genetic prevalences of WD. They also highlight the challenge in defining penetrance when assigning causality to some ATP7B variants.


Assuntos
ATPases Transportadoras de Cobre/genética , Variação Genética/genética , Degeneração Hepatolenticular/genética , Cobre/metabolismo , Bases de Dados de Ácidos Nucleicos , Frequência do Gene , Degeneração Hepatolenticular/epidemiologia , Humanos , Penetrância , Prevalência
19.
Biosci Rep ; 40(5)2020 05 29.
Artigo em Inglês | MEDLINE | ID: mdl-32301493

RESUMO

Mutations in the only known iron exporter ferroportin (FPN) in humans are associated with the autosomal dominantly inherited iron overload disorder ferroportin disease or type IV hereditary hemochromatosis (HH). While our knowledge of the central role of FPN in iron homeostasis has grown in the last 20 years, there exist some questions surrounding the structure and membrane topology of FPN with conflicting data on whether this receptor acts as a monomer or a multimer. To investigate and determine if FPN dimerization occurs in cells, we used novel tools including a variety of different FPN constructs expressing different tagged versions of the protein, a novel antibody that only detects cell surface FPN and proximity ligation assays. The results of the present study suggest that both the carboxy- and amino-termini of the FPN protein are intracellular. We also show that exogenously transfected FPN forms dimers; these dimers can be formed between the wild-type and mutant FPN proteins. This is the first study to examine the intracellular dimerization of FPN protein. Using proximity ligation assays, we show intracellular localization of FPN dimers and the interaction between FPN and hepcidin proteins as well. These results have important implications in the field of iron metabolism and add to our knowledge about FPN membrane topology and physiology of iron transport. This will be of importance in understanding the clinical implications of FPN mutations and of interest to future research aimed at targeting FPN expression to modulate iron homeostasis.

20.
Rheumatology (Oxford) ; 59(10): 2930-2938, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32107560

RESUMO

OBJECTIVE: Low disease activity (LDA) and remission are emerging treat-to-target (T2T) endpoints in SLE. However, the rates at which these endpoints are met in patients with high disease activity (HDA) are unknown. Atacicept, which targets B lymphocyte stimulator and a proliferation-inducing ligand, improved disease outcomes in SLE patients with HDA (SLEDAI-2K ≥10) at baseline in the phase 2b ADDRESS II study. This is a post hoc analysis of T2T endpoints in these patients. METHODS: Patients received weekly atacicept (75 or 150 mg s.c.) or placebo for 24 weeks (1:1:1 randomization). Attainment of three T2T endpoints, LDA (SLEDAI-2K ≤ 2), Lupus Low Disease Activity State (LLDAS) and remission (clinical SLEDAI-2K = 0, prednisone-equivalent ≤5mg/day and Physician's Global Assessment <0.5), was assessed and compared with SLE Responder Index (SRI)-4 and SRI-6 response. RESULTS: Of 306 randomized patients, 158 (51.6%) had baseline HDA. At week 24, 37 (23.4%) HDA patients attained LDA, 25 (15.8%) LLDAS and 17 (10.8%) remission. Each of these endpoints was more stringent than SRI-4 (n = 87; 55.1%) and SRI-6 (n = 67; 42.4%). Compared with placebo (n = 52), at week 24, patients treated with atacicept 150 mg (n = 51) were more likely to attain LDA [odds ratio (OR) 3.82 (95% CI: 1.44, 10.15), P = 0.007], LLDAS [OR 5.03 (95% CI: 1.32, 19.06), P = 0.018] or remission [OR 3.98 (95% CI: 0.78, 20.15), P = 0.095]. CONCLUSION: At week 24, LDA, LLDAS and remission were more stringent than SRI-4 and SRI-6 response, were attainable in the HDA population and discriminated between treatment with atacicept 150 mg and placebo. These results suggest that T2T endpoints are robust outcome measures in SLE clinical trials and support further evaluation of atacicept in SLE. TRAIL REGISTRATION: ClinicalTrials.gov, http://clinicaltrials.gov, NCT01972568.

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