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2.
Gynecol Oncol ; 181: 1-7, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38096673

RESUMO

OBJECTIVE: To describe the participation of racial and ethnic minority groups (REMGs) in gynecologic oncology trials. METHODS: Gynecologic oncology studies registered on ClinicalTrials.gov between 2007 and 2020 were identified. Trials with published results were analyzed based on reporting of race/ethnicity in relation to disease site and trial characteristics. Expected enrollment by race/ethnicity was calculated and compared to actual enrollment, adjusted for 2010 US Census population data. RESULTS: 2146 gynecologic oncology trials were identified. Of published trials (n = 252), 99 (39.3%) reported race/ethnicity data. Recent trials were more likely to report these data (36% from 2007 to 2009; 51% 2013-2015; and 53% from 2016 to 2018, p = 0.01). Of all trials, ovarian cancer trials were least likely to report race/ethnicity data (32.1% vs 39.3%, p = 0.011). Population-adjusted under-enrollment for Blacks was 7-fold in ovarian cancer, Latinx 10-fold for ovarian and 6-fold in uterine cancer trials, Asians 2.5-fold in uterine cancer trials, and American Indian and Alaska Native individuals 6-fold in ovarian trials. Trials for most disease sites have enrolled more REMGs in recent years - REMGs made up 19.6% of trial participants in 2007-2009 compared to 38.1% in 2016-2018 (p < 0.0001). CONCLUSION: Less than half of trials that published results reported race/ethnicity data. Available data reveals that enrollment of REMGs is significantly below expected rates based on national census data. These disparities persisted even after additionally adjusting for population size. Despite improvement in recent years, additional recruitment of REMGs is needed to achieve more representative and equitable participation in gynecologic cancer clinical trials.


Assuntos
Neoplasias dos Genitais Femininos , Neoplasias Ovarianas , Neoplasias Uterinas , Humanos , Feminino , Estados Unidos , Neoplasias dos Genitais Femininos/terapia , Etnicidade , Minorias Étnicas e Raciais , Grupos Minoritários , Neoplasias Ovarianas/terapia , Neoplasias Uterinas/terapia
3.
Ann Plast Surg ; 90(5S Suppl 3): S287-S294, 2023 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-37227408

RESUMO

BACKGROUND: Clinical trials form the backbone of evidence-based medicine. ClinicalTrials.gov is the world's largest clinical trial registry, and the state of clinical trials in plastic and reconstructive surgery (PRS) within that database has not been comprehensively studied. To that end, we explored the distribution of therapeutic areas that are under investigation, impact of funding on study design and data reporting, and trends in research patterns of all PRS interventional clinical trials registered with ClinicalTrials.gov. METHODS: Using the ClinicalTrials.gov database, we identified and extracted all clinical trials relevant to PRS that were submitted between 2007 and 2020. Studies were classified based on anatomic locations, therapeutic categories, and specialty topics. Cox proportional hazard was used to calculate adjusted hazard ratios (HRs) for early discontinuation and results reporting. RESULTS: A total of 3224 trials that included 372,095 participants were identified. The PRS trials grew at an annual rate of 7.9%. The therapeutic classes most represented were wound healing (41.3%) and cosmetics (18.1%). Funding for PRS clinical trials is largely provided through academic institutions (72.7%), while industry and US government constituted a minority. Industry-funded studies were more likely to be discontinued early than those funded by academics (HR, 1.89) or government (HR, 1.92) and to be nonblinded and nonrandomized. Academic-funded studies were the least likely to report results data within 3 years of trial completion (odds ratio, 0.87). CONCLUSIONS: A gulf exists in the representation of different PRS specialties among clinical trials. We highlight the role of funding source in trial design and data reporting to identify a potential source of financial waste and to stress the need for continued appropriate oversight.


Assuntos
Procedimentos de Cirurgia Plástica , Cirurgia Plástica , Humanos , Sistema de Registros , Projetos de Pesquisa
4.
Oncologist ; 28(6): 510-519, 2023 06 02.
Artigo em Inglês | MEDLINE | ID: mdl-36848266

RESUMO

BACKGROUND: Female underrepresentation in oncology clinical trials can result in outcome disparities. We evaluated female participant representation in US oncology trials by intervention type, cancer site, and funding. MATERIALS AND METHODS: Data were extracted from the publicly available Aggregate Analysis of ClinicalTrials.gov database. Initially, 270,172 studies were identified. Following the exclusion of trials using Medical Subject Heading terms, manual review, those with incomplete status, non-US location, sex-specific organ cancers, or lacking participant sex data, 1650 trials consisting of 240,776 participants remained. The primary outcome was participation to prevalence ratio (PPR): percent females among trial participants divided by percent females in the disease population per US Surveillance, Epidemiology, and End Results Program data. PPRs of 0.8-1.2 reflect proportional female representation. RESULTS: Females represented 46.9% of participants (95% CI, 45.4-48.4); mean PPR for all trials was 0.912. Females were underrepresented in surgical (PPR 0.74) and other invasive (PPR 0.69) oncology trials. Among cancer sites, females were underrepresented in bladder (odds ratio [OR] 0.48, 95% CI 0.26-0.91, P = .02), head/neck (OR 0.44, 95% CI 0.29-0.68, P < .01), stomach (OR 0.40, 95% CI 0.23-0.70, P < .01), and esophageal (OR 0.40 95% CI 0.22-0.74, P < .01) trials. Hematologic (OR 1.78, 95% CI 1.09-1.82, P < .01) and pancreatic (OR 2.18, 95% CI 1.46-3.26, P < .01) trials had higher odds of proportional female representation. Industry-funded trials had greater odds of proportional female representation (OR 1.41, 95% CI 1.09-1.82, P = .01) than US government and academic-funded trials. CONCLUSIONS: Stakeholders should look to hematologic, pancreatic, and industry-funded cancer trials as exemplars of female participant representation and consider female representation when interpreting trial results.


Assuntos
Neoplasias , Masculino , Humanos , Feminino , Estados Unidos/epidemiologia , Neoplasias/epidemiologia , Neoplasias/terapia , Oncologia , Razão de Chances , Bases de Dados Factuais , Prevalência
5.
JAMA Surg ; 158(2): 181-190, 2023 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-36542396

RESUMO

Importance: Clinical trials guide evidence-based obstetrics and gynecology (OB-GYN) but often enroll nonrepresentative participants. Objective: To characterize race and ethnicity reporting and representation in US OB-GYN clinical trials and their subsequent publications and to analyze the association of subspecialty and funding with diverse representation. Design and Setting: Cross-sectional analysis of all OB-GYN studies registered on ClinicalTrials.gov (2007-2020) and publications from PubMed and Google Scholar (2007-2021). Analyses included logistic regression controlling for year, subspecialty, phase, funding, and site number. Data from 332 417 studies were downloaded. Studies with a noninterventional design, with a registration date before October 1, 2007, without relevance to OB-GYN, with no reported results, and with no US-based study site were excluded. Exposures: OB-GYN subspecialty and funder. Main Outcomes and Measures: Reporting of race and ethnicity data and racial and ethnic representation (the proportion of enrollees of American Indian or Alaskan Native, Asian, Black, Latinx, or White identity and odds of representation above US Census estimates by race and ethnicity). Results: Among trials with ClinicalTrials.gov results (1287 trials with 591 196 participants) and publications (1147 trials with 821 111 participants), 662 (50.9%) and 856 (74.6%) reported race and ethnicity data, respectively. Among publications, gynecology studies were significantly less likely to report race and ethnicity than obstetrics (adjusted odds ratio [aOR], 0.54; 95% CI, 0.38-0.75). Reproductive endocrinology and infertility trials had the lowest odds of reporting race and ethnicity (aOR, 0.14; 95% CI, 0.07-0.27; reference category, obstetrics). Obstetrics and family planning demonstrated the most diverse clinical trial cohorts. Compared with obstetric trials, gynecologic oncology had the lowest odds of Black representation (ClinicalTrials.gov: aOR, 0.04; 95% CI, 0.02-0.09; publications: aOR, 0.06; 95% CI, 0.03-0.11) and Latinx representation (ClinicalTrials.gov: aOR, 0.05; 95% CI, 0.02-0.14; publications: aOR, 0.23; 95% CI, 0.10-0.48), followed by urogynecology and reproductive endocrinology and infertility. Urogynecology (ClinicalTrials.gov: aOR, 0.15; 95% CI, 0.05-0.39; publications: aOR, 0.24; 95% CI, 0.09-0.58) had the lowest odds of Asian representation. Conclusions and Relevance: Race and ethnicity reporting and representation in OB-GYN trials are suboptimal. Obstetrics and family planning trials demonstrate improved representation is achievable. Nonetheless, all subspecialties should strive for more equitably representative research.


Assuntos
Ginecologia , Equidade em Saúde , Infertilidade , Gravidez , Feminino , Humanos , Etnicidade , Estudos Transversais
6.
Obstet Gynecol ; 139(5): 821-831, 2022 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-35576341

RESUMO

OBJECTIVE: To characterize gynecology clinical trials over time, compare gynecology subspecialties, and analyze factors associated with early discontinuation, results reporting, and publication. METHODS: We conducted a cross-sectional analysis of all gynecology trials registered on ClinicalTrials.gov between 2007 and 2020 and their resulting publications. Trials were analyzed with descriptive, multivariable logistic, and Cox regression analyses. Primary exposure variables were trial funding and subspecialty. The three primary outcomes included early discontinuation, results reporting to ClinicalTrials.gov, and publication in a peer-reviewed journal indexed on PubMed. RESULTS: Of 223,690 trials registered on ClinicalTrials.gov between October 2007 and March 2020, only 3.7% focused on gynecology (n=8,174, approximately 3,759,086 participants). Subspecialties included reproductive endocrinology and infertility (n=1,428, 17.5%), gynecologic oncology (n=2,063, 25.2%), urogynecology (n=1,118, 13.7%), family planning (n=648, 7.9%), and other benign gynecology (n=2,917, 35.7%). Only 42.0% of completed trials disseminated results through results reporting and publication. Of all funding types, industry-funded trials were the most likely to be discontinued early (P<.001). Academic-funded trials were the least likely to report results (adjusted odds ratio [aOR] 0.38, 95% CI 0.30-0.50) but the most likely to publish (aOR 1.62, 95% CI 1.24-2.12). The number of reproductive endocrinology and infertility trials increased the most of any subspecialty between 2007 and 2020 (6.4% growth rate). Reproductive endocrinology and infertility and family planning trials were the most likely to be stopped early (reproductive endocrinology and infertility: adjusted hazard ratio [aHR] 2.08, 95% CI 1.59-2.71; family planning: aHR 1.55 95% CI 1.06-2.25). When completed, reproductive endocrinology and infertility trials were the least likely to report results (aOR 0.58, 95% CI 0.38-0.88). No significant differences were seen between subspecialties with respect to publication. CONCLUSION: Gynecology trials comprise only 3.7% of all clinical trials. The paucity of gynecology clinical trials aligns with decades of female underrepresentation in research. When completed, gynecology trials have poor dissemination. Our findings raise concern about bias in the performance, reporting, and publication of gynecology clinical trials.


Assuntos
Ginecologia , Infertilidade , Estudos Transversais , Feminino , Humanos , Razão de Chances , Relatório de Pesquisa
7.
Nat Med ; 28(2): 353-362, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-35027754

RESUMO

Severe immune-related adverse events (irAEs) occur in up to 60% of patients with melanoma treated with immune checkpoint inhibitors (ICIs). However, it is unknown whether a common baseline immunological state precedes irAE development. Here we applied mass cytometry by time of flight, single-cell RNA sequencing, single-cell V(D)J sequencing, bulk RNA sequencing and bulk T cell receptor (TCR) sequencing to study peripheral blood samples from patients with melanoma treated with anti-PD-1 monotherapy or anti-PD-1 and anti-CTLA-4 combination ICIs. By analyzing 93 pre- and early on-ICI blood samples and 3 patient cohorts (n = 27, 26 and 18), we found that 2 pretreatment factors in circulation-activated CD4 memory T cell abundance and TCR diversity-are associated with severe irAE development regardless of organ system involvement. We also explored on-treatment changes in TCR clonality among patients receiving combination therapy and linked our findings to the severity and timing of irAE onset. These results demonstrate circulating T cell characteristics associated with ICI-induced toxicity, with implications for improved diagnostics and clinical management.


Assuntos
Inibidores de Checkpoint Imunológico , Melanoma , Humanos , Inibidores de Checkpoint Imunológico/efeitos adversos , Melanoma/tratamento farmacológico , Estudos Retrospectivos , Linfócitos T
9.
JAMA Netw Open ; 4(6): e2113749, 2021 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-34143192

RESUMO

Importance: Although female representation has increased in clinical trials, little is known about how clinical trial representation compares with burden of disease or is associated with clinical trial features, including disease category. Objective: To describe the rate of sex reporting (ie, the presence of clinical trial data according to sex), compare the female burden of disease with the female proportion of clinical trial enrollees, and investigate the associations of disease category and clinical trial features with the female proportion of clinical trial enrollees. Design, Setting, and Participants: This cross-sectional study included descriptive analyses and logistic and generalized linear regression analyses with a logit link. Data were downloaded from the Aggregate Analysis of ClinicalTrials.gov database for all studies registered between March 1, 2000, and March 9, 2020. Enrollment was compared with data from the 2016 Global Burden of Disease database. Of 328 452 clinical trials, 70 095 were excluded because they had noninterventional designs, 167 936 because they had recruitment sites outside the US, 69 084 because they had no reported results, 1003 because they received primary funding from the US military, and 314 because they had unclear sex categories. A total of 20 020 interventional studies enrolling approximately 5.11 million participants met inclusion criteria and were divided into those with and without data on participant sex. Exposures: The primary exposure variable was clinical trial disease category. Secondary exposure variables included funding, study design, and study phase. Main Outcomes and Measures: Sex reporting and female proportion of participants in clinical trials. Results: Among 20 020 clinical trials from 2000 to 2020, 19 866 studies (99.2%) reported sex, and 154 studies (0.8%) did not. Clinical trials in the fields of oncology (46% of disability-adjusted life-years [DALYs]; 43% of participants), neurology (56% of DALYs; 53% of participants), immunology (49% of DALYs; 46% of participants), and nephrology (45% of DALYs; 42% of participants) had the lowest female representation relative to corresponding DALYs. Male participants were underrepresented in 8 disease categories, with the greatest disparity in clinical trials of musculoskeletal disease and trauma (11.3% difference between representation and proportion of DALYs). Clinical trials of preventive interventions were associated with greater female enrollment (adjusted relative difference, 8.48%; 95% CI, 3.77%-13.00%). Clinical trials in cardiology (adjusted relative difference, -18.68%; 95% CI, -22.87% to -14.47%) and pediatrics (adjusted relative difference, -20.47%; 95% CI, -25.77% to -15.16%) had the greatest negative association with female enrollment. Conclusions and Relevance: In this study, sex differences in clinical trials varied by clinical trial disease category, with male and female participants underrepresented in different medical fields. Although sex equity has progressed, these findings suggest that sex bias in clinical trials persists within medical fields, with negative consequences for the health of all individuals.


Assuntos
Efeitos Psicossociais da Doença , Sujeitos da Pesquisa/estatística & dados numéricos , Adulto , Estudos Transversais , Feminino , Humanos , Modelos Logísticos , Fatores Sexuais , Estados Unidos
10.
Adv Radiat Oncol ; 6(2): 100644, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33732962

RESUMO

PURPOSE: Postoperative stereotactic radiosurgery (SRS) is associated with up to 30% risk of subsequent leptomeningeal disease (LMD). Radiographic patterns of LMD (classical sugarcoating [cLMD] vs. nodular [nLMD]) in this setting has been shown to be prognostic. However, the association of these findings with neurologic death (ND) is not well described. METHODS AND MATERIALS: The records for patients with brain metastases who underwent surgical resection and adjunctive SRS to 1 lesion (SRS to other intact lesions was allowed) and subsequently developed LMD were combined from 7 tertiary care centers. Salvage radiation therapy (RT) for LMD was categorized according to use of whole-brain versus focal cranial RT. RESULTS: The study cohort included 125 patients with known cause of death. The ND rate in these patients was 79%, and the rate in patients who underwent LMD salvage treatment (n = 107) was 76%. Univariate logistic regression demonstrated radiographic pattern of LMD (cLMD vs. nLMD, odds ratio: 2.9; P = .04) and second LMD failure after salvage treatment (odds ratio: 3.9; P = .02) as significantly associated with ND. The ND rate was 86% for cLMD versus 68% for nLMD. Whole-brain RT was used in 95% of patients with cLMD and 52% with nLMD. In the nLMD cohort (n = 58), there was no difference in ND rate based on type of salvage RT (whole-brain RT: 67% vs. focal cranial RT: 68%, P = .92). CONCLUSIONS: LMD after surgery and SRS for brain metastases is a clinically significant event with high rates of ND. Classical LMD pattern (vs. nodular) and second LMD failure after salvage treatment were significantly associated with a higher risk of ND. Patients with nLMD treated with salvage focal cranial RT did not have higher ND rates compared with WBRT. Methods to decrease LMD and the subsequent high risk of ND in this setting warrant further investigation.

11.
World Neurosurg ; 146: 80-84, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33130141

RESUMO

BACKGROUND: Radiation therapy for intracranial lesions is constrained by dose to neurologic organs at risk. CASE DESCRIPTION: We report 2 cases, a newly diagnosed chondrosarcoma and a previously irradiated meningioma, with tumors that abutted the optic chiasm following subtotal resection. Definitive radiotherapy would have required either undercoverage of the tumor or treatment of the chiasm with doses posing an unacceptable risk of blindness. Therefore, the patients underwent open surgery with placement of an abdominal fat autograft to provide space between the tumor and the optic structures at risk. Patients received definitive fractionated stereotactic radiotherapy. For each patient, we retrospectively compared the treated plan (with fat autograft) to a second plan generated using the pre-autograft imaging, maintaining similar tumor coverage. For the chondrosarcoma, the fat autograft reduced the optic chiasm maximum dose by 21% (70.4 Gy to 55.3 Gy). For the reirradiated peri-optic meningioma, the optic chiasm maximum dose was reduced by 10% (50.8 Gy to 45.9 Gy), the left optic nerve by 17% (48.9 Gy to 40.4 Gy), and the right optic nerve by 30% (32.3 Gy to 22.6 Gy). CONCLUSIONS: We demonstrate the utility of abdominal fat autograft placement to maximize coverage of tumor while minimizing dose to intracranial organs at risk.


Assuntos
Gordura Abdominal/transplante , Neoplasias Encefálicas/radioterapia , Quiasma Óptico/efeitos da radiação , Lesões por Radiação/prevenção & controle , Radiocirurgia/métodos , Adulto , Autoenxertos , Condrossarcoma/radioterapia , Feminino , Humanos , Masculino , Neoplasias Meníngeas/radioterapia , Meningioma/radioterapia , Recidiva Local de Neoplasia/radioterapia , Órgãos em Risco , Radiometria , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador/métodos
12.
Int J Radiat Oncol Biol Phys ; 106(3): 579-586, 2020 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-31605786

RESUMO

PURPOSE: For brain metastases, surgical resection with postoperative stereotactic radiosurgery is an emerging standard of care. Postoperative cavity stereotactic radiosurgery is associated with a specific, underrecognized pattern of intracranial recurrence, herein termed nodular leptomeningeal disease (nLMD), which is distinct from classical leptomeningeal disease. We hypothesized that there is poor consensus regarding the definition of LMD, and that a formal, self-guided training module will improve interrater reliability (IRR) and validity in diagnosing LMD. METHODS AND MATERIALS: Twenty-two physicians at 16 institutions, including 15 physicians with central nervous system expertise, completed a 2-phase survey that included magnetic resonance imaging and treatment information for 30 patients. In the "pretraining" phase, physicians labeled cases using 3 patterns of recurrence commonly reported in prospective studies: local recurrence (LR), distant parenchymal recurrence (DR), and LMD. After a self-directed training module, participating physicians completed the "posttraining" phase and relabeled the 30 cases using the 4 following labels: LR, DR, classical leptomeningeal disease, and nLMD. RESULTS: IRR increased 34% after training (Fleiss' Kappa K = 0.41 to K = 0.55, P < .001). IRR increased most among non-central nervous system specialists (+58%, P < .001). Before training, IRR was lowest for LMD (K = 0.33). After training, IRR increased across all recurrence subgroups and increased most for LMD (+67%). After training, ≥27% of cases initially labeled LR or DR were later recognized as nLMD. CONCLUSIONS: This study highlights the large degree of inconsistency among clinicians in recognizing nLMD. Our findings demonstrate that a brief self-guided training module distinguishing nLMD can significantly improve IRR across all patterns of recurrence, and particularly in nLMD. To optimize outcomes reporting, prospective trials in brain metastases should incorporate central imaging review and investigator training.


Assuntos
Neoplasias Encefálicas/diagnóstico por imagem , Carcinomatose Meníngea/diagnóstico por imagem , Recidiva Local de Neoplasia/diagnóstico por imagem , Neuroimagem/normas , Radiocirurgia , Autoaprendizagem como Assunto , Neoplasias Encefálicas/radioterapia , Neoplasias Encefálicas/secundário , Transtornos Cognitivos/prevenção & controle , Consenso , Diagnóstico Diferencial , Humanos , Imageamento por Ressonância Magnética , Carcinomatose Meníngea/radioterapia , Carcinomatose Meníngea/cirurgia , Neurologistas , Variações Dependentes do Observador , Cuidados Pós-Operatórios , Reprodutibilidade dos Testes , Terminologia como Assunto
13.
Neuro Oncol ; 21(8): 1049-1059, 2019 08 05.
Artigo em Inglês | MEDLINE | ID: mdl-30828727

RESUMO

BACKGROUND: Radiographic leptomeningeal disease (LMD) develops in up to 30% of patients following postoperative stereotactic radiosurgery (SRS) for brain metastases. However, the clinical relevancy of this finding and outcomes after various salvage treatments are not known. METHODS: Patients with brain metastases, of which 1 was resected and treated with adjunctive SRS, and who subsequently developed LMD were combined from 7 tertiary care centers. LMD pattern was categorized as nodular (nLMD) or classical ("sugarcoating," cLMD). RESULTS: The study cohort was 147 patients. Most patients (60%) were symptomatic at LMD presentation, with cLMD more likely to be symptomatic than nLMD (71% vs. 51%, P = 0.01). Salvage therapy was whole brain radiotherapy (WBRT) alone (47%), SRS (27%), craniospinal radiotherapy (RT) (10%), and other (16%), with 58% receiving a WBRT-containing regimen. WBRT was associated with lower second LMD recurrence compared with focal RT (40% vs 68%, P = 0.02). Patients with nLMD had longer median overall survival (OS) than those with cLMD (8.2 vs 3.3 mo, P < 0.001). On multivariable analysis for OS, pattern of initial LMD (nodular vs classical) was significant, but type of salvage RT (WBRT vs focal) was not. CONCLUSIONS: Nodular LMD is a distinct pattern of LMD associated with postoperative SRS that is less likely to be symptomatic and has better OS outcomes than classical "sugarcoating" LMD. Although focal RT demonstrated increased second LMD recurrence compared with WBRT, there was no associated OS detriment. Focal cranial RT for nLMD recurrence after surgery and SRS for brain metastases may be a reasonable alternative to WBRT.


Assuntos
Neoplasias Encefálicas , Neoplasias Meníngeas , Radiocirurgia , Neoplasias Encefálicas/radioterapia , Neoplasias Encefálicas/cirurgia , Irradiação Craniana , Humanos , Neoplasias Meníngeas/radioterapia , Neoplasias Meníngeas/cirurgia , Estudos Retrospectivos , Terapia de Salvação
14.
Physiol Rep ; 2(12)2014 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-25501423

RESUMO

Hypoxia causes an increase in pulmonary artery pressure. Gene expression controlled by the hypoxia-inducible factor (HIF) family of transcription factors plays an important role in the underlying pulmonary vascular responses. The hydroxylase enzymes that regulate HIF are highly sensitive to varying iron availability, and iron status modifies the pulmonary vascular response to hypoxia, possibly through its effects on HIF. Ascorbate (vitamin C) affects HIF hydroxylation in a similar manner to iron and may therefore have similar pulmonary effects. This study investigated the possible contribution of ascorbate availability to hypoxic pulmonary vasoconstriction in humans. Seven healthy volunteers undertook a randomized, controlled, double-blind, crossover protocol which studied the effects of high-dose intravenous ascorbic acid (total 6 g) on the pulmonary vascular response to 5 h of sustained hypoxia. Systolic pulmonary artery pressure (SPAP) was assessed during hypoxia by Doppler echocardiography. Results were compared with corresponding data from a similar study investigating the effect of intravenous iron, in which SPAP was measured in seven healthy volunteers during 8 h of sustained hypoxia. Consistent with other studies, iron supplementation profoundly inhibited hypoxic pulmonary vasoconstriction (P < 0.001). In contrast, supraphysiological supplementation of ascorbate did not affect the increase in pulmonary artery pressure induced by several hours of hypoxia (P = 0.61). We conclude that ascorbate does not interact with hypoxia and the pulmonary circulation in the same manner as iron. Whether the effects of iron are HIF-mediated remains unknown, and the extent to which ascorbate contributes to HIF hydroxylation in vivo is also unclear.

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