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1.
J Pediatr Orthop ; 2024 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-38803000

RESUMO

BACKGROUND: The long-term prognosis of baseball and softball players diagnosed with Little League elbow (LLE) and Little League shoulder (LLS) is unknown. Many of these athletes are potentially at risk of developing future shoulder and elbow injuries that may require surgical intervention. This study's purpose is to retrospectively assess 5-year patient-reported outcomes and career progression of a series of youth baseball and softball players diagnosed with LLE and LLS. METHODS: This institutional review board-approved, single-center, retrospective study evaluated 5-year outcomes of a cohort of youth baseball and softball players diagnosed with LLE and LLS between 2013 and 2017. Demographic and clinical data was recorded including age, gender, primary position, and months played per year. A standardized phone survey was obtained approximately 5 years post-treatment to assess upper extremity function, career progression, and pain recurrence. RESULTS: Sixty-one patients (44 LLE, 17 LLS) met the inclusion criteria and participated in a standardized phone survey. The mean age at the time of diagnosis was 13.2 years and all but one of the athletes were male. On average, about 80% (34/44 LLE, 15/17 LLS) played baseball 9 months or more per year. After diagnosis and nonoperative management, more than 80% (37/44 LLE, 14/17 LLS) were able to return to competition, but up to 40% of players changed positions (9/44 LLE, 7/17 LLS). Five years later, less than half (21/44 LLE, 8/17 LLS) were playing baseball actively. The recurrence rate was >20% (9/42 LLE, 6/17 LLS) with a mean time of recurrence of 8.8 months. Patients who experienced symptom recurrence were less likely to play baseball 5 years later and had lower patient-reported outcomes. CONCLUSIONS: A diagnosis of LLE and LLS in early adolescence can be a setback for a young athlete. Fortunately, most athletes will be able to return to competition with ∼50% still competing at 5 years. Very few will progress to future arm surgery, but recurrence rates are relatively high, and these athletes are less likely to participate in their sport 5 years later. LEVEL OF EVIDENCE: Level IV-Retrospective cohort study.

2.
Foot Ankle Orthop ; 8(3): 24730114231200482, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37786608

RESUMO

Background: The modified Lapidus (ML) is a powerful procedure for correction of hallux valgus (HV) with emerging techniques. Studies considering patient-reported outcomes, radiographic measures, complications, and implant costs are currently limited. Methods: Retrospective cohort with prospectively collected Patient Reported Outcome Information System Physical Function (PROMIS-PF) Computerized Adaptive Test (CAT) scores, radiographic parameters (intermetatarsal angle, IMA; hallux valgus angle, HVA; and tibial sesamoid position, TSP), complications, and total operative time and implant costs were reviewed from 2014 to 2019. Results: Seventy-three feet (68 patients) underwent bunion correction by ML with lag-screw fixation. Median age was 55.8 years (IQR 45.6, 53.9), 4 of 73 (5.5%) were male, 11 of 73 (15.1%) were smokers, and 15 of 73 (20.6%) were diabetic (median HbA1c 6.4% [IQR 6.0, 7.4], none insulin dependent, 5 of 15 with neuropathy). Complications included 6 of 73 (8.2%) wound issues resolved with topical or oral treatment, 9 of 73 (12.3%) painful or broken hardware requiring hardware removal. Two of 73 (2.7%) had persistent pain despite union. One of 73 (1.4%) was overcorrected and required first MTP arthrodesis. Of 3 nonunions (2.7%), 1 resolved with corrected hypothyroidism, 1 was asymptomatic and required no treatment, 1 had a hallux valgus recurrence and sought revision surgery elsewhere. Preoperative radiographic angles were HVA 35 degrees, IMA 14 degrees which improved at final postoperative follow up to HVA 10 degrees, IMA 6 degrees. Tibial sesamoid position improved from 6.05 ± 1.00 to 2.22 ± 1.38. Thirty-two patients had preoperative and 42 had 1-year postoperative outcomes. PROMIS-PF (51% collection rate) was 43 (IQR 37,52) preoperatively, 37 (31, 39) at 6 weeks, 46 (42, 51) at 3 months, and 49 (41, 53) at >360 days postoperatively. The drop in PROMIS-PF between preoperative and 6 weeks and the rise from 6 weeks to 3 months were statistically significant. Pre- and postoperative PROMIS-PF scores were not significantly different. Implant cost averaged US$146. Discussion/Conclusion: We report low complication rates and costs with high patient postoperative functional and radiographic outcomes. PROMIS-PF decreased acutely postoperatively but recovered and maintained high levels by 3 months postoperatively. Level of Evidence: Level IV, case series.

3.
J Pediatr Orthop ; 43(8): e619-e624, 2023 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-37311653

RESUMO

BACKGROUND: The purpose of this study was to evaluate the rate of residual acetabular dysplasia (RAD), defined as an acetabular index (AI) of >90th percentile of age and sex-matched controls, in a cohort of infants successfully treated with the Pavlik harness (PH). METHODS: We retrospectively studied typically developing infants at a single center, with at least 1 dislocated hip, that was successfully treated with a PH and had a minimum of 48 months follow-up. Hip dislocation was defined as <30% femoral head coverage at rest on pretreatment ultrasound or IHDI grade 3 or 4 on the pretreatment radiograph. RESULTS: Forty-six dislocated hips (41 infants) were studied (4 males and 37 females). Brace treatment was initiated at an average age of 1.8 months (range: 2 d to 9.3 mo) and was maintained for an average of 10.2 months (range: 2.3 to 24.9 mo). All hips achieved IHDI grade 1 reduction. Five of 46 hips (11%) had an AI >90th percentile at the conclusion of bracing. Average follow-up was 6.5 years (range: 4.0 to 15.2 y). We found a 30% incidence of RAD (14/46 hips) on final follow-up radiographs. Of these hips, 13/14 (93%) had AI <90th percentile at the end of brace treatment. Comparing children with and without RAD, there were no differences in age at the initial visit or brace initiation, total follow-up, femoral head coverage at the initial visit, alpha angle at the initial visit, or total time in the brace ( P > 0.09). CONCLUSION: In a single-center cohort of infants with dislocated hips treated successfully with a PH, we observed a 30% incidence of RAD at a minimum 4.0-year follow-up. Normal acetabular morphology at the end of brace treatment did not result in normal acetabular morphology at the final follow-up in 13/41 hips (32%). We recommend that surgeons should pay close attention to the year-over-year change in both the AI and AI percentile. LEVEL OF EVIDENCE: Level IV: case series.


Assuntos
Luxação Congênita de Quadril , Luxação do Quadril , Masculino , Lactente , Feminino , Criança , Humanos , Estudos Retrospectivos , Aparelhos Ortopédicos , Incidência , Resultado do Tratamento , Fatores de Tempo , Luxação Congênita de Quadril/diagnóstico por imagem , Luxação Congênita de Quadril/epidemiologia , Luxação Congênita de Quadril/terapia , Acetábulo/diagnóstico por imagem
4.
J Biomech ; 149: 111473, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36791514

RESUMO

The ability to efficiently and reproducibly generate subject-specific 3D models of bone and soft tissue is important to many areas of musculoskeletal research. However, methodologies requiring such models have largely been limited by lengthy manual segmentation times. Recently, machine learning, and more specifically, convolutional neural networks, have shown potential to alleviate this bottleneck in research throughput. Thus, the purpose of this work was to develop a modified version of the convolutional neural network architecture U-Net to automate segmentation of the tibia and femur from double echo steady state knee magnetic resonance (MR) images. Our model was trained on a dataset of over 4,000 MR images from 34 subjects, segmented by three experienced researchers, and reviewed by a musculoskeletal radiologist. For our validation and testing sets, we achieved dice coefficients of 0.985 and 0.984, respectively. As further testing, we applied our trained model to a prior study of tibial cartilage strain and recovery. In this analysis, across all subjects, there were no statistically significant differences in cartilage strain between the machine learning and ground truth bone models, with a mean difference of 0.2 ± 0.7 % (mean ± 95 % confidence interval). This difference is within the measurement resolution of previous cartilage strain studies from our lab using manual segmentation. In summary, we successfully trained, validated, and tested a machine learning model capable of segmenting MR images of the knee, achieving results that are comparable to trained human segmenters.


Assuntos
Aprendizado Profundo , Tíbia , Humanos , Tíbia/diagnóstico por imagem , Articulação do Joelho/diagnóstico por imagem , Cartilagem , Fêmur/diagnóstico por imagem , Imageamento por Ressonância Magnética/métodos , Processamento de Imagem Assistida por Computador/métodos
5.
J Arthroplasty ; 38(5): 798-805, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-36470363

RESUMO

BACKGROUND: Slipped capital femoral epiphysis (SCFE) causes degenerative changes warranting total hip arthroplasty (THA) in approximately 50% of patients by age 60 years. For severe SCFE, a reorienting intertrochanteric osteotomy (ITO) following in situ pinning (ISP) can decrease impingement with hip flexion, but by altering proximal femoral geometry, complicates subsequent conversion THA. We hypothesized that increasing implant survivorship would affect the most cost-effective treatment strategy (ISP followed by ITO [ISP + ITO] with later THA versus ISP alone [ISPa] with earlier THA) over a patient's lifetime. METHODS: A state-transition Markov model was constructed to analyze the cost-effectiveness of either ISPa or ISP + ITO over a 60-year time horizon for children who have severe, stable SCFE. Transition probabilities associated with implant and native hip survivorship, state utilities, and costs were derived from the literature. Sensitivity analyses assessed the model robustness. Incremental cost-effectiveness ratios (ICERs) were compared to a societal willingness to pay (WTP) of $100,000 per quality-adjusted life year (QALY). RESULTS: Over a 60-year horizon, ISPa was costlier ($291,836) than ISP + ITO ($75,227) but achieved overall better outcomes (51.4 QALYs ISPa versus 48.7 QALYs ISP + ITO), rendering ISPa cost-effective with an ICER of $80,980/QALY. Implant survivorship and time horizon were sensitive variables. CONCLUSION: Based upon current implant performance, ISPa with subsequent earlier THA is cost-effective when considering an individual's life expectancy and thereby deserves consideration in patients who have severe SCFE. Without clear level 1 clinical data, our economic model considers a difficult problem, while providing families and clinicians with a framework for understanding treatment options. LEVEL OF EVIDENCE: Economic and decision analysis, Level III.


Assuntos
Artroplastia de Quadril , Osteoartrite do Quadril , Escorregamento das Epífises Proximais do Fêmur , Criança , Humanos , Pessoa de Meia-Idade , Escorregamento das Epífises Proximais do Fêmur/cirurgia , Escorregamento das Epífises Proximais do Fêmur/complicações , Artroplastia de Quadril/efeitos adversos , Osteoartrite do Quadril/cirurgia , Análise Custo-Benefício , Resultado do Tratamento
6.
J Pediatr Orthop ; 42(9): 462-466, 2022 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-35973055

RESUMO

BACKGROUND: Patient-reported outcome measures are useful tools to quantify patients' pre-treatment and post-treatment symptoms. Historically used "legacy measures", such as the Scoliosis Research Society-22 revised questionnaire (SRS-22r), are often disease-specific and can be time-intensive. Recently developed Patient-Reported Outcomes Measurement Information System (PROMIS) computerized adaptive testing (CAT) measures may reduce administrative burdens and permit more efficient outcome collection within clinic workflows. In an era of medicine where payments are becoming tied to outcomes, we sought to assess the time to completion (TTC) of 8 pediatric PROMIS CAT measures and the SRS-22r in adolescents with idiopathic scoliosis. MATERIALS AND METHODS: Patients presenting to a large, urban tertiary referral hospital were prospectively enrolled into the study. Subjects were first-time survey respondents in various phases and types of treatment for adolescent idiopathic scoliosis. In total, 200 patients ranging from 10 to 17 years old completed 8 Pediatric PROMIS CATs and the SRS-22r. PROMIS CATs administered include Physical Activity, Mobility, Anxiety, Depressive symptoms, Peer Relationships, Physical Stress Experiences, Pain Behavior and Pain Interference. TTC was calculated using start and stop timestamps in the REDCap software. RESULTS: The mean (±SD) TTC for each PROMIS CAT was 1.1 (±0.9) minutes with physical activity, mobility, anxiety, depressive symptoms, peer relationships, physical stress experiences, pain behavior, and pain interference taking 1.2, 1.4, 1.0, 0.9, 1.2, 1.0, 1.0, and 1.2 minutes on average to complete, respectively. Mean TTC for the SRS-22r was 5.2 (±3.0) minutes. CONCLUSIONS: In this pediatric orthopaedic cohort, completion of 8 PROMIS CATs demonstrated minimal test-taker burden and time required for completion. These findings support rapid and easily integrable PROMIS CATs in clinical practice to aid in increased delivery of efficient, patient-centered care. LEVEL OF EVIDENCE: III, cross-sectional study.


Assuntos
Cifose , Escoliose , Teste Adaptativo Computadorizado , Estudos Transversais , Humanos , Dor , Medidas de Resultados Relatados pelo Paciente , Qualidade de Vida , Escoliose/diagnóstico , Escoliose/terapia
7.
Cartilage ; 13(1_suppl): 1402S-1410S, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-33588577

RESUMO

OBJECTIVE: The primary aim was to determine differences in talocrural and subtalar joint (STJ) articular cartilage composition, using T1ρ magnetic resonance imaging (MRI) relaxation times, between limbs in individuals with unilateral chronic ankle instability (CAI) and compare with an uninjured control. Our secondary purpose was to determine the association between talocrural and STJ composition in limbs with and without CAI. DESIGN: T1ρ MRI relaxation times were collected on 15 CAI (11 females, 21.13 ± 1.81 years, body mass index [BMI] = 23.96 ± 2.74 kg/m2) and 15 uninjured control individuals (11 females, 21.07 ± 2.55 years, BMI = 24.59 ± 3.44 kg/m2). Talocrural cartilage was segmented manually to identify the overall talar dome. The SJT cartilage was segmented manually to identify the anterior, medial, and posterior regions of interest consistent with STJ anatomical articulations. For each segmented area, a T1ρ relaxation time mean and variability value was calculated. Greater T1ρ relaxation times were interpreted as decreased proteoglycan content. RESULTS: Individuals with CAI demonstrated a higher involved limb talocrural T1ρ mean and variability relative to their contralateral limb (P < 0.05) and the healthy control limb (P < 0.05). The CAI-involved limb also had a higher posterior STJ T1ρ mean relative to the healthy control limb (P < 0.05). In healthy controls (P < 0.05), but not the CAI-involved or contralateral limbs (p>0.05), talocrural and posterior STJ composition measures were positively associated. CONCLUSIONS: Individuals with CAI have lower proteoglycan content in both the talocrural and posterior STJ in their involved limbs relative to the contralateral and a healthy control limb. Cartilage composition findings may be consistent with the early development of posttraumatic osteoarthritis.


Assuntos
Articulação do Tornozelo/diagnóstico por imagem , Tornozelo , Instabilidade Articular/diagnóstico , Imageamento por Ressonância Magnética/métodos , Adolescente , Adulto , Estudos de Casos e Controles , Estudos Transversais , Feminino , Humanos
8.
Spine (Phila Pa 1976) ; 46(14): 950-957, 2021 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-33428363

RESUMO

STUDY DESIGN: Cost-effectiveness analysis. OBJECTIVE: To determine if bariatric surgery prior to posterior lumbar decompression and fusion (PLDF) for degenerative spondylolisthesis (DS) is a cost-effective strategy. SUMMARY OF BACKGROUND DATA: Obesity poses significant perioperative challenges for DS. Treated operatively, obese patients achieve worse outcomes relative to non-obese peers. Concomitantly, they fare better with surgery than with nonoperative measures. These competing facts create uncertainty in determining optimal treatment algorithms for obese patients with DS. The role of bariatric surgery merits investigation as a potentially cost-effective optimization strategy prior to PLDF. METHODS: We simulated a Markov model with two cohorts of obese individuals with DS. 10,000 patients with body mass index (BMI) more than or equal to 30 in both arms were candidates for both bariatric surgery and PLDF. Subjects were assigned either to (1) no weight loss intervention with immediate operative or nonoperative management ("traditional arm") or (2) bariatric surgery 2 years prior to entering the same management options ("combined protocol").Published costs, utilities, and transition probabilities from the literature were applied. A willingness to pay threshold of $100,000/QALY was used. Sensitivity analyses were run for all variables to assess the robustness of the model. RESULTS: Over a 10-year horizon, the combined protocol was dominant ($13,500 cheaper, 1.15 QALY more effective). Changes in utilities of operative and nonoperative treatments in non-obese patients, the obesity cost-multiplier, cost of bariatric surgery, and the probability of success of nonoperative treatment in obese patients led to decision changes. However, all thresholds occurred outside published bounds for these variables. CONCLUSION: The combined protocol was less costly and more effective than the traditional protocol. Results were robust with thresholds occurring outside published ranges. Bariatric surgery is a viable, cost-effective preoperative strategy in obese patients considering elective PLDF for DS.Level of Evidence: 3.


Assuntos
Cirurgia Bariátrica , Descompressão Cirúrgica , Obesidade , Fusão Vertebral , Espondilolistese , Cirurgia Bariátrica/efeitos adversos , Cirurgia Bariátrica/economia , Cirurgia Bariátrica/estatística & dados numéricos , Análise Custo-Benefício , Descompressão Cirúrgica/efeitos adversos , Descompressão Cirúrgica/economia , Descompressão Cirúrgica/estatística & dados numéricos , Humanos , Obesidade/complicações , Obesidade/epidemiologia , Obesidade/cirurgia , Fusão Vertebral/efeitos adversos , Fusão Vertebral/economia , Fusão Vertebral/estatística & dados numéricos , Espondilolistese/complicações , Espondilolistese/epidemiologia , Espondilolistese/cirurgia , Redução de Peso
9.
Sci Rep ; 9(1): 2283, 2019 02 19.
Artigo em Inglês | MEDLINE | ID: mdl-30783146

RESUMO

Cartilage metabolism-both the synthesis and breakdown of cartilage constituents and architecture-is influenced by its mechanical loading. Therefore, physical activity is often recommended to maintain cartilage health and to treat or slow the progression of osteoarthritis, a debilitating joint disease causing cartilage degeneration. However, the appropriate exercise frequency, intensity, and duration cannot be prescribed because direct in vivo evaluation of cartilage following exercise has not yet been performed. To address this gap in knowledge, we developed a cartilage stress test to measure the in vivo strain response of healthy human subjects' tibial cartilage to walking exercise. We varied both walk duration and speed in a dose-dependent manner to quantify how these variables affect cartilage strain. We found a nonlinear relationship between walk duration and in vivo compressive strain, with compressive strain initially increasing with increasing duration, then leveling off with longer durations. This work provides innovative measurements of cartilage creep behavior (which has been well-documented in vitro but not in vivo) during walking. This study showed that compressive strain increased with increasing walking speed for the speeds tested in this study (0.9-2.0 m/s). Furthermore, our data provide novel measurements of the in vivo strain response of tibial cartilage to various doses of walking as a mechanical stimulus, with maximal strains of 5.0% observed after 60 minutes of walking. These data describe physiological benchmarks for healthy articular cartilage behavior during walking and provide a much-needed baseline for studies investigating the effect of exercise on cartilage health.


Assuntos
Cartilagem Articular/fisiopatologia , Articulação do Joelho/fisiopatologia , Estresse Mecânico , Teste de Caminhada , Caminhada , Adulto , Feminino , Humanos , Masculino
10.
J Bone Joint Surg Am ; 99(24): e133, 2017 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-29257021

RESUMO

BACKGROUND: Femoroacetabular impingement (FAI) syndrome is an increasingly recognized source of hip pain and disability in young active adults. In order to confirm the diagnosis, providers often supplement physical examination maneuvers and radiographs with intra-articular hip injection, magnetic resonance imaging (MRI), or magnetic resonance arthrography (MRA). Since diagnostic imaging represents the fastest rising cost segment in U.S. health care, there is a need for value-driven diagnostic algorithms. The purpose of this study was to identify cost-effective diagnostic strategies for symptomatic FAI, comparing history and physical examination (H&P) alone (utilizing only radiographic imaging) with supplementation with injection, MRI, or MRA. METHODS: A simple-chain decision model run as a cost-utility analysis was constructed to assess the diagnostic value of the MRI, MRA, and injection that are added to the H&P and radiographs in diagnosing symptomatic FAI. Strategies were compared using the incremental cost-utility ratio (ICUR) with a willingness to pay (WTP) of $100,000/QALY (quality-adjusted life year). Direct costs were measured using the Humana database (PearlDiver). Diagnostic test accuracy, treatment outcome probabilities, and utilities were extracted from the literature. RESULTS: H&P with and without supplemental diagnostic injection was the most cost-effective. Adjunct injection was preferred in situations with a WTP of >$60,000/QALY, low examination sensitivity, and high FAI prevalence. With low disease prevalence and low examination sensitivity, as may occur in a general practitioner's office, H&P with injection was the most cost-effective strategy, whereas in the reciprocal scenario, H&P with injection was only favored at exceptionally high WTP (∼$990,000). CONCLUSIONS: H&P and radiographs with supplemental diagnostic injection are preferred over advanced imaging, even with reasonable deviations from published values of disease prevalence, test sensitivity, and test specificity. Providers with low examination sensitivity in situations with low disease prevalence may benefit most from including injection in their diagnostic strategy. Providers with high examination sensitivity in situations with high disease prevalence may not benefit from including injection in their diagnostic strategy. Providers should not routinely rely on advanced imaging to diagnose FAI syndrome, although advanced imaging may have a role in challenging clinical scenarios. LEVEL OF EVIDENCE: Economic and Decision Analysis Level IV. See Instructions for Authors for a complete description of levels of evidence.


Assuntos
Artrografia/métodos , Meios de Contraste , Análise Custo-Benefício , Impacto Femoroacetabular/diagnóstico por imagem , Imageamento por Ressonância Magnética/métodos , Adulto , Artrografia/economia , Estudos de Coortes , Técnicas de Apoio para a Decisão , Feminino , Impacto Femoroacetabular/fisiopatologia , Humanos , Injeções Intra-Articulares , Imageamento por Ressonância Magnética/economia , Masculino , Exame Físico/métodos , Sensibilidade e Especificidade , Índice de Gravidade de Doença , Adulto Jovem
11.
Prog Biomater ; 3(1): 20, 2014 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-29470669

RESUMO

Peripheral nerve regeneration can be enhanced by chemical and mechanical cues for neurite growth. Aligned and randomly oriented electrospun nanofibers of poly(ε-caprolactone) (PCL) or a blend of PCL and elastin were fabricated to test their potential to provide contact guidance to embryonic chick dorsal root ganglia for peripheral nerve regeneration. Scanning electron microscopy was used to analyze the fiber diameter. Fiber diameter was found to be significantly smaller when elastin was incorporated into the scaffold (934 ± 58 nm for PCL and 519 ± 36 nm for PCL:elastin). After 24 h in culture, there was preferential cell attachment and neurite extension along the fibers of the elastin-containing scaffolds (average neurite extension 173.4 ± 20.7 µm), indicating that the presence of elastin promotes neurite outgrowth on electrospun scaffolds.

12.
PLoS One ; 8(4): e60452, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23593222

RESUMO

To elucidate the regulation of glucocorticoid receptor (GR) signaling under pro-asthmatic conditions, cultured human airway smooth muscle (HASM) cells were treated with proinflammatory cytokines or GR ligands alone and in combination, and then examined for induced changes in ligand-dependent and -independent GR activation and downstream signaling events. Ligand stimulation with either cortisone or dexamethsone (DEX) acutely elicited GR translocation to the nucleus and, comparably, ligand-independent stimulation either with the Th2 cytokine, IL-13, or the pleiotropic cytokine combination, IL-1ß/TNFα, also acutely evoked GR translocation. The latter response was potentiated by combined exposure of cells to GR ligand and cytokine. Similarly, treatment with either DEX or IL-13 alone induced GR phosphorylation at its serine-211 residue (GR(Ser211)), denoting its activated state, and combined treatment with DEX+IL-13 elicited heightened and sustained GR(Ser211) phosphorylation. Interestingly, the above ligand-independent GR responses to IL-13 alone were not associated with downstream GR binding to its consensus DNA sequence or GR transactivation, whereas both DEX-induced GR:DNA binding and transcriptional activity were significantly heightened in the presence of IL-13, coupled to increased recruitment of the transcriptional co-factor, MED14. The stimulated GR signaling responses to DEX were prevented in IL-13-exposed cells wherein GR(Ser211) phosphorylation was suppressed either by transfection with specific serine phosphorylation-deficient mutant GRs or treatment with inhibitors of the MAPKs, ERK1/2 and JNK. Collectively, these novel data highlight a heretofore-unidentified homeostatic mechanism in HASM cells that involves pro-asthmatic cytokine-driven, MAPK-mediated, non-ligand-dependent GR activation that confers heightened glucocorticoid ligand-stimulated GR signaling. These findings raise the consideration that perturbations in this homeostatic cytokine-driven GR signaling mechanism may be responsible, at least in part, for the insensirtivity to glucocorticoid therapy that is commonly seen in individuals with severe asthma.


Assuntos
Citocinas/farmacologia , Músculo Liso/efeitos dos fármacos , Músculo Liso/metabolismo , Receptores de Glucocorticoides/metabolismo , Sistema Respiratório/efeitos dos fármacos , Sistema Respiratório/metabolismo , Transdução de Sinais/efeitos dos fármacos , Asma/genética , Asma/metabolismo , Núcleo Celular/metabolismo , Células Cultivadas , Ativação Enzimática/efeitos dos fármacos , Humanos , Ligantes , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Mutação , Fosforilação/efeitos dos fármacos , Ligação Proteica , Transporte Proteico/efeitos dos fármacos , Receptores de Glucocorticoides/genética , Elementos de Resposta , Ativação Transcricional
13.
Am J Physiol Lung Cell Mol Physiol ; 303(5): L382-90, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22773690

RESUMO

Endogenous glucocorticoid (GC) activation is regulated by the intracellular GC-activating and -inactivating enzymes 11ß-hydroxysteroid dehydrogenase (11ß-HSD)1 and 11ß-HSD2, respectively, that catalyze interconversion of inert cortisone and its bioactive metabolite cortisol. Because endogenous GCs are critically implicated in suppressing the asthmatic state, this study examined the roles of the 11ß-HSD enzymes in regulating GC activation and bronchoprotection during proasthmatic stimulation. Airway hyperresponsiveness to methacholine and inflammation were assessed in rabbits following inhalation of the proasthmatic/proinflammatory cytokine IL-13 with and without pretreatment with the 11ß-HSD inhibitor carbenoxolone (CBX). Additionally, IL-13-induced changes in 11ß-HSD isozyme expression and GC metabolism were examined in epithelium-intact and -denuded tracheal segments and peripheral lung tissues. Finally, the effects of pretreatment with CBX or 11ß-HSD2-targeted siRNAs were investigated with respect to cortisol prevention of IL-13-induced airway constrictor hyperresponsiveness and eotaxin-3 production by airway epithelial cells. IL-13-exposed rabbits exhibited airway hyperresponsiveness, inflammation, and elevated bronchoalveolar lung fluid levels of eotaxin-3. These responses were inhibited by pretreatment with CBX, suggesting a permissive proasthmatic role for 11ß-HSD2. Supporting this concept, extended studies demonstrated that 1) IL-13-treated tracheal epithelium and peripheral lung tissues exhibit upregulated 11ß-HSD2 activity, 2) the latter impairs cortisone-induced cortisol accumulation and the ability of administered cortisol to prevent both IL-13-induced heightened airway contractility and eotaxin-3 release from epithelial cells, and 3) these proasthmatic responses are prevented by cortisol administration in the presence of 11ß-HSD2 inhibition. Collectively, these data demonstrate that the proasthmatic effects of IL-13 are enabled by impaired endogenous GC activation in the lung that is attributed to upregulation of 11ß-HSD2 in the pulmonary epithelium.


Assuntos
Asma/metabolismo , Glucocorticoides/metabolismo , Interleucina-13/fisiologia , Pulmão/metabolismo , 11-beta-Hidroxiesteroide Desidrogenase Tipo 1/antagonistas & inibidores , 11-beta-Hidroxiesteroide Desidrogenase Tipo 1/genética , 11-beta-Hidroxiesteroide Desidrogenase Tipo 1/metabolismo , 11-beta-Hidroxiesteroide Desidrogenase Tipo 2/antagonistas & inibidores , 11-beta-Hidroxiesteroide Desidrogenase Tipo 2/genética , 11-beta-Hidroxiesteroide Desidrogenase Tipo 2/metabolismo , Animais , Asma/enzimologia , Asma/patologia , Broncoconstritores/farmacologia , Carbenoxolona/farmacologia , Quimiocinas CC/genética , Quimiocinas CC/metabolismo , Cortisona/metabolismo , Expressão Gênica , Hidrocortisona/metabolismo , Interleucina-13/administração & dosagem , Isoenzimas/antagonistas & inibidores , Isoenzimas/genética , Isoenzimas/metabolismo , Pulmão/enzimologia , Pulmão/patologia , Cloreto de Metacolina/farmacologia , Músculo Liso/enzimologia , Músculo Liso/metabolismo , Pneumonia/enzimologia , Pneumonia/metabolismo , Coelhos , Mucosa Respiratória/enzimologia , Mucosa Respiratória/metabolismo , Traqueia/patologia
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