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1.
J Foot Ankle Surg ; 59(3): 479-483, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32354504

RESUMO

Current nationwide epidemiological data regarding ankle fractures are scarce. Such information is important towards better quantifying the mortality associated with such injuries, financial impact, as well as the implementation of preventative measures. This study evaluated the epidemiology of ankle fractures that occurred during a 5-year period. Specifically, we evaluated demographics, mechanism of injury, and disposition. The National Electronic Injury Surveillance System was queried to identify all patients with ankle fractures that presented to US hospital emergency departments between 2012 and 2016. Census data were used to determine the incidence rates of ankle fractures in terms of age, sex, and race. There was an estimated total of 673,214 ankle fractures that occurred during this period, with an incidence rate of 4.22/10,000 person-years. The mean age of patients with an ankle fracture was 37 ± 22.86 (SD) years; 23.5% of ankle fractures occurred in patients aged 10 to 19 years (7.56/10,000 person-years). In addition, 44% of ankle fractures occurred in men (3.81/10,000 person-years), whereas 56% occurred in women (4.63/10,000 person-years). Data on race/ethnicity were available for 71% of the subjects, with incidence rates of 2.85/10,000 person-years for whites, 3.01/10,000 person-years for blacks, and 4.08/10,000 person-years for others. The most common mechanism of injury was falls (54.83%), followed by sports (20.76%), exercise (16.84%), jumping (4.42%), trauma (2.84%), and other (0.30%). For disposition, 81.84% of patients were treated and released, 1.43% were transferred, 16.01% were admitted, 0.59% were held for observation, and 0.13% left against medical advice. The highest incidence of ankle fractures in men occurred in the 10-to-19-years age group, but women were more commonly affected in all other age groups.


Assuntos
Fraturas do Tornozelo/epidemiologia , Acidentes por Quedas/estatística & dados numéricos , Adolescente , Adulto , Distribuição por Idade , Idoso , Idoso de 80 Anos ou mais , Fraturas do Tornozelo/diagnóstico , Fraturas do Tornozelo/terapia , Traumatismos em Atletas/diagnóstico , Traumatismos em Atletas/epidemiologia , Traumatismos em Atletas/terapia , Criança , Pré-Escolar , Serviço Hospitalar de Emergência/estatística & dados numéricos , Feminino , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Fatores de Risco , Distribuição por Sexo , Estados Unidos/epidemiologia , Adulto Jovem
2.
Foot Ankle Int ; 43(3): 371-377, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-34549617

RESUMO

BACKGROUND: Total ankle arthroplasty (TAA) is an increasingly popular option for the operative treatment of ankle arthritis. The Cadence TAA entered clinical use in 2016 and was designed to address common failure modes of prior systems. We report early complications and radiographic and clinical outcomes of this total ankle system at a minimum of 2 years of follow-up. METHODS: We performed a retrospective review of a consecutive cohort of patients undergoing primary Cadence TAA by a single surgeon from 2016 to 2017. Complications and reoperations were documented using the American Orthopaedic Foot & Ankle Society (AOFAS) TAA reoperation coding system. Patients completed the Foot and Ankle Ability Measure (FAAM) Activities of Daily Living (ADL) and Sport subscales, SF-12 Mental (MCS) and Physical (PCS) Component Summaries, and visual analog scale (VAS) pain rating (0-100). Radiographic evaluation was performed to assess postoperative range of motion (ROM) of the sole of the foot relative to the long axis of the tibia, alignment, and implant complications. RESULTS: Fifty-eight patients with a mean age of 63.3 years and mean body mass index of 31.9 kg/m2 were included. Twelve of 58 patients (20.7%) underwent an additional procedure(s) within 2 years, including 3 (5.2%) who required removal of one or both components, 2 for infection and 1 for osteolysis. Forty-three patients were followed for a minimum of 2 years with radiographic imaging; 1 patient's (2.3%) radiographs had signs of peri-implant osteolysis, with no cases demonstrating loosening or subsidence. FAAM-ADL, FAAM-Sport, SF-12 PCS, and VAS pain scores all improved at a mean of 27.4 months postoperatively, with mean score changes (± SD) of 16.3 (± 22.0), 25.3 (± 24.5), 6.0 (± 11.1), and -32.3 (± 39.8), respectively. Radiographic analysis revealed that average coronal alignment improved from 6.9 degrees from neutral preoperatively to 2.3 degrees postoperatively. The average ROM of the foot relative to the tibia was 36.5 degrees total arc of motion based on lateral radiographs. CONCLUSION: Early experience with this 2-component total ankle replacement was associated with a high component retention rate, improved coronal plane alignment, good postoperative ROM, radiographically stable implants, and improved patient function. LEVEL OF EVIDENCE: Level IV, case series.


Assuntos
Artroplastia de Substituição do Tornozelo , Atividades Cotidianas , Tornozelo/cirurgia , Articulação do Tornozelo/diagnóstico por imagem , Articulação do Tornozelo/cirurgia , Artroplastia de Substituição do Tornozelo/métodos , Humanos , Pessoa de Meia-Idade , Amplitude de Movimento Articular , Estudos Retrospectivos , Resultado do Tratamento
3.
Foot Ankle Int ; 42(12): 1517-1524, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34293952

RESUMO

BACKGROUND: It is currently unclear how injury to the spring ligament (SL) affects the preoperative presentation of adult acquired flatfoot deformity (AAFD) or the outcome of operative reconstruction. The purposes of this study were to assess the preoperative features and pre- or postoperative function of patients who underwent direct operative repair of an SL tear compared to those without a tear. METHODS: 86 patients undergoing operative correction of grade 2B AAFD by a single fellowship-trained foot and ankle orthopaedic surgeon were reviewed at an average follow-up of 45.9 months. There were 35 feet found to have an SL tear that underwent concomitant debridement and direct repair of the SL. Patient charts were reviewed for demographic information, preoperative visual analog scale (VAS) pain level, and their Foot and Ankle Ability Measure (FAAM) activities of daily living (ADL) and sports subscales. Preoperative radiographic parameters were assessed. Patient outcomes of VAS pain, FAAM-ADL, and FAAM-Sports were collected and compared between groups. RESULTS: Those with an SL tear had significantly lower FAAM-ADL and sports scores, with higher VAS pain scores preoperatively. Patient age, talonavicular uncoverage percentage, and talonavicular angle were found to be associated with spring ligament degeneration. At final follow-up, patients demonstrated a significant improvement in all outcome parameters, with no statistical difference found with patient satisfaction, final postoperative VAS pain, FAAM-ADL, or FAAM-Sports in those requiring a repair of their SL as compared to the control group. CONCLUSION: Increasing patient age, increasing talonavicular uncoverage percentage, and decreasing talonavicular angle are all independently associated with increased likelihood of patients with AAFD having an SL tear. At follow-up for operative treatment of grade 2B AAFD flatfoot with our approach, we found no clinical outcomes difference between those without SL tears and those with SL tears treated with concomitant SL debridement and repair. LEVEL OF EVIDENCE: Level III, retrospective cohort study.


Assuntos
Pé Chato , Deformidades Adquiridas do Pé , Atividades Cotidianas , Adulto , Pé Chato/diagnóstico por imagem , Pé Chato/cirurgia , Humanos , Ligamentos Articulares/cirurgia , Estudos Retrospectivos
4.
Cureus ; 13(7): e16391, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34408944

RESUMO

INTRODUCTION: With no current "gold standard" fixation strategy for syndesmotic injuries and differences in preferred preoperative and intraoperative diagnostic techniques and criteria, methods of reduction, fixation constructs, and postoperative management, the goals of this study were to determine how orthopaedic surgeons currently manage ankle fractures with concomitant syndesmotic disruption, as well as to identify surgeon demographics predictive of syndesmotic management techniques. METHODS: This study was conducted as a web-based survey of foot and ankle fellowship-trained surgeons, Orthopaedic Trauma Association (OTA) members, and Canadian Orthopaedic Association (COA) members. The survey, sent and completed via the HIPAA-compliant Research Electronic Data Capture (REDCap) system, consisted of 18 questions: 6 surgeon demographic questions and 12 specific syndesmotic management questions regarding perioperative protocols and syndesmotic fixation construct techniques. RESULTS: One hundred and ten orthopaedic surgeons completed our survey. Years of practice and type of fellowship were found to be the variables that influenced perioperative syndesmotic management strategies the most, while a number of fractures operated on per year, country of practice, and practice setting also influenced management decisions. Additionally, 59% (65/110) surgeons indicated that the way they have managed syndesmotic injuries has changed at some point in their career, while 33% (36/110) specified that they could foresee themselves changing their management of these injuries in the future. CONCLUSIONS: There was significant variability among responders in preoperative and intraoperative assessment technique, fixation construct, screw removal protocol, and postoperative weightbearing protocol. This study raises awareness of differences in and factors predictive of management strategies and should be used for further discussion when determining a potential gold standard for the management of these complex injuries.

5.
Foot Ankle Spec ; 14(3): 219-225, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32174166

RESUMO

Background. Despite the absence of complications and a restoration of normal hallux alignment, some patients have suboptimal outcomes from hallux valgus correction surgery. One risk factor for persistent pain may be the presence of arthritic changes at the metatarsal head articulation with the sesamoids, an area not easily assessed with standard radiographs unless dedicated sesamoid views are obtained. In this study, we prospectively evaluated the metatarsal head for degenerative changes during hallux valgus correction surgery and identified preoperative risk factors associated with these changes. Methods. We prospectively evaluated 200 feet in 196 patients who underwent hallux valgus surgery intraoperatively for the pattern and severity of arthritic changes at the metatarsal head. Mann-Whitney U testing was implemented to compare differences in arthritic scores between preoperative deformity groups. The Spearman correlation test was used to determine the association between age and preoperative deformity with the severity of degenerative changes. Results. More than half of all feet assessed had severe arthritic changes at the plantar medial aspect of the metatarsal head and 40% of feet at the plantar lateral aspect. Age and intermetatarsal angle were found to be positively correlated with arthritis in this area. Conclusion. Our prospective study has demonstrated the high prevalence of arthritic changes at the metatarsal head sesamoid articulation and the positive influence of age and severity of deformity on metatarsal head arthritic changes seen during hallux valgus correction surgery. Furthermore, these arthritic changes were found to have no significant influence on preoperative functional and pain levels.Levels of Evidence: Level IV: Case series.


Assuntos
Artrite/epidemiologia , Artrite/etiologia , Hallux Valgus/cirurgia , Ossos do Metatarso , Articulação Metatarsofalângica , Ossos Sesamoides , Fatores Etários , Artrite/patologia , Feminino , Hallux Valgus/complicações , Humanos , Achados Incidentais , Masculino , Ossos do Metatarso/patologia , Articulação Metatarsofalângica/patologia , Pessoa de Meia-Idade , Osteotomia/métodos , Prevalência , Estudos Prospectivos , Ossos Sesamoides/patologia , Índice de Gravidade de Doença
6.
Foot Ankle Spec ; 13(4): 315-323, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31347393

RESUMO

Background: Tibiotalocalcaneal (TTC) arthrodesis implementing adjunctive allografts is a method of limb salvage for patients with complex hindfoot osseous deficits, though outcome results are limited. The purposes of this study were to assess functional and radiographic outcomes after TTC arthrodesis with femoral head allograft and retrospectively identify prognostic factors. Methods: The authors reviewed 24 TTC arthrodesis procedures with bulk femoral head allografts performed by a single surgeon from 2004 to 2016. Radiographic union at the ankle and subtalar joints along with stability of the allograft were assessed. Patients who had clinically successful arthrodeses were contacted to score the Foot and Ankle Ability Measure-Activities of Daily Living (FAAM-ADL) questionnaire, Visual Analog Scale (VAS) for pain, and Short Form-12 (SF-12) at a mean of 58.0 months (range, 28-102) postoperatively. Results: Complete radiographic union of involved joints was achieved in 15 patients (63%) and in 75% (36/48) of all joints; 21 ankles (88%) were assessed to be radiographically stable at final follow-up. Three patients (13%) underwent revision arthrodesis at a mean of 18.9 months postoperatively, and 21 patients (88%) did not require additional surgery as of final follow-up. Patients significantly improved to a mean FAAM-ADL score of 71.5 from 36.3 (P < .001). The mean VAS for pain significantly improved from 77.2 to 32.9 (P < .001). Male sex (P = .08) and a lateral operative approach (P = .03) both resulted in worse outcomes. Conclusion: Use of a femoral head allograft with TTC arthrodesis can offer improved functional scores and sustained radiographic outcomes.Level of Evidence: Level IV: Case series.


Assuntos
Artrodese/métodos , Calcâneo/cirurgia , Cabeça do Fêmur/transplante , Recuperação de Função Fisiológica , Tálus/cirurgia , Tíbia/cirurgia , Idoso , Aloenxertos , Calcâneo/diagnóstico por imagem , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Tálus/diagnóstico por imagem , Tíbia/diagnóstico por imagem , Fatores de Tempo , Resultado do Tratamento
7.
Cureus ; 12(4): e7712, 2020 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-32431990

RESUMO

Introduction Orthopaedic surgeons choose to manage communication with their patients outside of official visits and interactions in a variety of ways, with some choosing to provide their personal cell phone number in order to provide patients with direct accessibility. The objective of this prospective study is to explore to what extent patients utilize the cell phone numbers of orthopaedic surgeons in the immediate period after it is provided to them. Methods Seven fellowship-trained orthopaedic surgeons from five different subspecialties in a single private, multi-site group each provided his/her personal cell phone number to 30 consecutive patients. The surgeon's phone number was written down on a business card, and the surgeons themselves provided the card to the patient. Phone calls and voice mail messages received in the 30 days following the patient receiving the phone number were recorded, and the reasons for these calls were categorized as being "appropriate" (e.g. acute postoperative issues, unclear instructions) or "inappropriate" (e.g. administrative issues, medication refills, advanced imaging-related inquires). Results Two-hundred seven patients with an average age of 51.5 years were provided cell phone numbers. During the 30 days following administration of cell phone numbers to each patient, 21 patients (10.1%) made calls to their surgeons, for an average of 0.15 calls per patient. Six patients (2.9%) called their surgeons more than once. Seventeen calls (54.8%) were deemed appropriate, while 14 calls (45.2%) were inappropriate. Logistic regression analysis did not reveal patient age, sex, type of visit, or surgeon subspecialty to be independently associated with calling. Conclusion Our study has demonstrated a low rate of patient utilization of surgeon cell phone number when provided to them. If surgeons choose to provide their cell phone number to patients, we recommend specifying appropriate reasons to call in order to maximize the effectiveness of this communication method.

8.
J Orthop ; 22: 225-230, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32425422

RESUMO

PURPOSE: To assess the success rate and complications of the surgical interventions used to manage chronic syndesmosis injuries. METHODS: Multiple online databases were queried to identify studies reporting operative intervention for chronic syndesmosis injuries. RESULTS: Modalities of operative fixation include suture-button fixation, arthroscopy and debridement, as well as arthrodesis. The use of operative treatment is effective; however, more direct comparison studies are necessary to evaluate the efficacy of each treatment. CONCLUSION: Various operative procedures have been used for the management of chronic syndesmotic injuries but further prospective studies are necessary to determine the type of treatment that should be indicated.

9.
Foot Ankle Int ; 40(4): 402-407, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30565478

RESUMO

BACKGROUND:: Lateral column lengthening and plantarflexion dorsal opening wedge osteotomy of the medial cuneiform are 2 commonly used procedures to address the deformity seen in severe flexible pes planovalgus deformity. Traditionally, iliac crest allograft or autograft has been used to fill the osteotomy sites. Porous metallic wedges can be used as an alternative to avoid the concerns associated with both autograft and allograft. METHODS:: We performed a retrospective review of patients who had corrective osteotomies utilizing metallic wedges to address flexible pes planovalgus with at least 2 years of follow-up data. Preoperative radiographic measurements (anteroposterior [AP] and talo-first metatarsal angle, calcaneal pitch, talocalcaneal angle, and talonavicular uncoverage angle) and functional scores (visual analog scale [VAS] pain, Foot and Ankle Ability Measure [FAAM] Activities of Daily Living [ADL], FAAM Sports) were compared to postoperative radiographic measurements and functional scores. RESULTS:: There were statistically significant improvements in all radiographic parameters and functional scores. Two nonunions were seen, one of which healed with revision surgery while the other was asymptomatic. At the time of last radiographic follow-up, there were no recurrences of deformity or collapse. CONCLUSION:: Porous metallic wedges offer an attractive alternative to autograft and/or allograft in the setting of corrective osteotomies for severe flexible pes planovalgus. Patients who underwent corrective osteotomies using these wedges demonstrated reliable, effective, and stable radiographic correction as well as significant improvements in function and pain. LEVEL OF EVIDENCE:: Level IV, case series.


Assuntos
Calcâneo/cirurgia , Pé Chato/cirurgia , Osteotomia , Implantação de Prótese , Ossos do Tarso/cirurgia , Calcâneo/diagnóstico por imagem , Calcâneo/patologia , Feminino , Pé Chato/diagnóstico por imagem , Pé Chato/patologia , Humanos , Masculino , Pessoa de Meia-Idade , Medição da Dor , Porosidade , Próteses e Implantes , Radiografia , Estudos Retrospectivos , Inquéritos e Questionários , Ossos do Tarso/diagnóstico por imagem , Ossos do Tarso/patologia , Titânio
10.
Clin Podiatr Med Surg ; 35(1): 77-83, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29156169

RESUMO

Total ankle arthroplasty is an increasingly popular procedure to address tibiotalar joint arthritis. Implant design and the rationale behind it have changed throughout the years. Newer generation implants allow for minimal resection of bone and use fixed-bearing technology. Long-term follow-up multicenter studies will determine the lifetime of these devices and their effectiveness in addressing pain and improving function for patients with endstage tibiotalar arthritis.


Assuntos
Articulação do Tornozelo/cirurgia , Artrite/cirurgia , Artroplastia de Substituição do Tornozelo/métodos , Humanos , Prótese Articular , Desenho de Prótese
11.
J Orthop Surg (Hong Kong) ; 25(1): 2309499016684724, 2017 01.
Artigo em Inglês | MEDLINE | ID: mdl-28176601

RESUMO

We evaluated the risks and success rates of the three major techniques for compartment syndrome fasciotomy closure by reviewing all literature published to date. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, we systematically evaluated the Medline (PubMed) database until July 2015, utilizing the Boolean search sting "compartment syndrome OR fasciotomy closure." Two authors independently assessed all studies published in the literature to ensure validity of extracted data. The data was compiled into an electronic spreadsheet, and the wound closure rate with each technique was assessed utilizing a proportion random model effect. Success was defined as all wounds that could be closed without skin grafting, amputation, or death. The highest success rate was observed for dynamic dermatotraction and gradual suture approximation, whereas vacuum-assisted closure had the lowest complication rate.


Assuntos
Síndromes Compartimentais/cirurgia , Fasciotomia , Técnicas de Fechamento de Ferimentos , Humanos
12.
A A Case Rep ; 8(4): 81-85, 2017 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-28045723

RESUMO

A 52-year-old woman, ASA II (American Society of Anesthesia classification II) scheduled for cholecystectomy in an ambulatory center, exhibited a wide-complex tachycardia with ectopy on the monitor after induction with propofol and succinylcholine. Blood pressure remained stable; amiodarone was administered for presumed ventricular tachycardia. A 12-lead electrocardiogram (ECG) showed a new left bundle branch block (LBBB) at 98 beats per minute (bpm), which resolved when the heart rate slowed. Surgery was postponed, and both the LBBB and ectopy recurred frequently during the next 24 hours in the intensive care unit, particularly at heart rates >90 bpm. Troponins were normal, and the patient was diagnosed with a rate-dependent LBBB and cleared for surgery.


Assuntos
Procedimentos Cirúrgicos Ambulatórios/tendências , Bloqueio de Ramo/diagnóstico , Bloqueio de Ramo/fisiopatologia , Frequência Cardíaca , Bloqueio de Ramo/cirurgia , Eletrocardiografia/tendências , Feminino , Frequência Cardíaca/fisiologia , Humanos , Pessoa de Meia-Idade
13.
J Clin Orthop Trauma ; 7(Suppl 1): 92-98, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-28018083

RESUMO

While bisphosphonates have been shown to be effective in reducing the incidence of typical osteoporotic fractures, long-term bisphosphonate may be associated with atypical femoral fractures. We report a case of a bisphosphonate-related impending atypical femoral fracture which progressed despite prophylactic cephalomedullary nailing. The fracture healed without further surgical intervention after correcting the patient's bone metabolic profile and stopping the possible offending factors. Although prophylactic fixation of these fractures is recommended, our case and relevant literature review demonstrate that a simple fixation without optimizing other possible predisposing factors may not prevent progression of these fractures.

14.
J Long Term Eff Med Implants ; 26(2): 161-165, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-28094740

RESUMO

Injuries involving the distal tibiofibular syndesmosis can lead to critical destabilization of the ankle mortise. Although specific indications for operative fixation remain unclear, accurate reduction of the syndesmosis has been correlated with the best functional outcomes. The purpose of this study was to evaluate the maximum torque and rotation to failure after fixation with a novel construct. Seven pairs (14 ankles) of embalmed cadaveric lower legs, disarticulated at the knee, were obtained. Each pair was randomly assigned to receive either two TightRopes (Arthrex) or a plate-and-screw construct with one TightRope. All samples were mechanically tested in torsion to determine peak torque, torsional stiffness, and the maximum rotation angle at which failure occurred. Differences between the groups were compared using paired Student's t test. The maximum torque to failure after fixation was not significantly different between the two TightRopes (28.8 N*m; range, 7.3-49.7 N*m) and the one TightRope group (29.5 N*m; range, 9.2-44.9 N*m; p = 0.92). The maximum rotation to fracture after fixation was not significantly different between the two TightRopes (33.3 degrees; range, 21.6-57.0 degrees) and one TightRope group (38.6 degrees; range, 23.0-73.9 degrees). All specimens failed with the fracture of the fibula at the level of the inferior syndesmotic screw. The similar load to failure of the two TightRope and the one TightRope and plate-and-screw plate suggested similar stiffness between the two constructs. The addition of the plate may improve distribution of forces at the level of syndesmosis, reducing stress risers and decreasing the risk of failure, as demonstrated by a lower rotation to failure of the one TightRope with plate-and-screw construct. In addition, this construct is not likely to not be associated with any substantial cost increase. Further clinical studies may further elucidate the role of plate and/or TightRope augmentation to syndesmosis fixation.


Assuntos
Traumatismos do Tornozelo/cirurgia , Placas Ósseas , Parafusos Ósseos , Fraturas Ósseas/cirurgia , Fenômenos Biomecânicos , Cadáver , Fíbula , Fixação Interna de Fraturas , Humanos , Distribuição Aleatória
15.
PLoS One ; 8(2): e56949, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23437279

RESUMO

The Hypoxia-inducible Factor (HIF) family of transcriptional regulators coordinates the expression of dozens of genes in response to oxygen deprivation. Mammalian development occurs in a hypoxic environment and HIF-null mice therefore die in utero due to multiple embryonic and placental defects. Mouse embryonic stem cells do not differentiate into placental cells; therefore, trophoblast stem cells (TSCs) are used to study mouse placental development. Consistent with a requirement for HIF activity during placental development in utero, TSCs derived from HIF-null mice exhibit severe differentiation defects and fail to form trophoblast giant cells (TGCs) in vitro. Interestingly, differentiating TSCs induce HIF activity independent of oxygen tension via unclear mechanisms. Here, we show that altering the extracellular matrix (ECM) composition upon which TSCs are cultured changes their differentiation potential from TGCs to multinucleated syncytiotropholasts (SynTs) and blocks oxygen-independent HIF induction. We further find that modulation of Mitogen Activated Protein Kinase Kinase-1/2 (MAP2K1/2, MEK-1/2) signaling by ECM composition is responsible for this effect. In the absence of ECM-dependent cues, hypoxia-signaling pathways activate this MAPK cascade to drive HIF induction and redirect TSC fate along the TGC lineage. In addition, we show that integrity of the microtubule and actin cytoskeleton is critical for TGC fate determination. HIF-2α ensures TSC cytoskeletal integrity and promotes invasive TGC formation by interacting with c-MYC to induce non-canonical expression of Lim domain kinase 1-an enzyme that regulates microtubule and actin stability, as well as cell invasion. Thus, we find that HIF can integrate positional and metabolic cues from within the TSC niche to regulate placental development by modulating the cellular cytoskeleton via non-canonical gene expression.


Assuntos
Citoesqueleto/metabolismo , Matriz Extracelular/metabolismo , Fator 1 Induzível por Hipóxia/metabolismo , Quinases Lim/metabolismo , Células-Tronco/citologia , Células-Tronco/metabolismo , Trofoblastos/citologia , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Diferenciação Celular/genética , Feminino , Humanos , Fator 1 Induzível por Hipóxia/genética , Quinases Lim/genética , MAP Quinase Quinase 1/metabolismo , MAP Quinase Quinase 2/metabolismo , Camundongos , Modelos Biológicos , Consumo de Oxigênio , Gravidez , Estabilidade Proteica , Transdução de Sinais
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