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1.
J Gastrointest Surg ; 27(9): 1794-1803, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-37316761

RESUMO

BACKGROUND: Neoadjuvant tyrosine kinase inhibitor (TKI) therapy has reduced tumor burden and improved survival in both primary and recurrent gastrointestinal stromal tumors (GISTs). However, no clear guidelines exist on optimal patient selection for neoadjuvant therapy (NAT). Our aim was to analyze factors and outcomes associated with the therapeutic sequence of TKI therapy before and/or after surgery for gastric GISTs. METHODS: We performed a retrospective study of patients surgically treated for a gastric GIST utilizing the 2006-2018 National Cancer Database. We examined demographic, clinical, and pathological characteristics associated with NAT versus adjuvant therapy (AT) using logistic regression. RESULTS: Of the 3732 patients, 20.4% received NAT and 79.6% had AT. Among patients receiving therapy, NAT significantly increased over our study period (12% to 30.7%). A majority of the AT group received a partial gastrectomy (77.9%) compared with the NAT group who received more near-total/total gastrectomy or gastrectomy with en bloc resection (p < 0.001). In a multivariable model, patients were more likely to receive NAT when insured (private, aOR: 2.37, 95% CI: 1.31-4.29), treated at an academic/research program (aOR: 1.83, 95% CI: 1.49-2.56), had tumors located in the proximal stomach (aOR: 1.40, 95% CI: 1.06-1.86), tumor size > 10 cm (aOR: 1.88, 95% CI: 1.41-2.51), and received near-total/total gastrectomy (aOR: 1.81, 95% CI: 1.42-2.29). There were no differences in outcomes. CONCLUSION: NAT for gastric GIST has increased in utilization. NAT was used in patients with larger tumors and who underwent more extensive resection. Despite these factors, outcomes were similar to patients receiving only AT. More studies are required to determine the therapeutic sequence for gastric GISTs.


Assuntos
Tumores do Estroma Gastrointestinal , Neoplasias Gástricas , Humanos , Tumores do Estroma Gastrointestinal/tratamento farmacológico , Tumores do Estroma Gastrointestinal/cirurgia , Terapia Neoadjuvante , Estudos Retrospectivos , Recidiva Local de Neoplasia/cirurgia , Neoplasias Gástricas/cirurgia , Neoplasias Gástricas/patologia , Gastrectomia
2.
Surgery ; 172(2): 559-566, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35437162

RESUMO

BACKGROUND: Neuroendocrine tumors can cause ectopic Cushing syndrome, and most patients have metastatic disease at diagnosis. We identified risk factors for outcome, evaluated ectopic Cushing syndrome management, and explored the role of bilateral adrenalectomy in this population. METHODS: This was a retrospective study including patients with diagnosis of ectopic Cushing Syndrome secondary to neuroendocrine tumors with adrenocorticotropic hormone secretion treated at our quaternary referral center over a 40-year period (1980-2020). RESULTS: Seventy-six patients were included. Mean age at diagnosis was 46.3 ± 15.8 years. Most patients (N = 61, 80%) had metastases at ectopic Cushing syndrome diagnosis. Average follow-up was 2.9 ± 3.7 years (range, 4 months-17.2 years). Patients with neuroendocrine tumors before ectopic Cushing syndrome had more frequent metastatic disease and resistant ectopic Cushing syndrome. Patients with de novo hyperglycemia, poor neuroendocrine tumor differentiation, and metastatic disease had worse survival. Of those with nonmetastatic disease, 8 (53%) had ectopic Cushing syndrome resolution after neuroendocrine tumor resection, 3 (20%) were medically controlled, and 4 (27%) underwent bilateral adrenalectomy. In patients with metastatic neuroendocrine tumors, hypercortisolism was initially medically managed in 92%, 3% underwent immediate bilateral adrenalectomy, 2% had control after primary neuroendocrine tumor debulking, and 2% were lost to follow-up. Medical treatment resulted in hormonal control in 7 (13%) patients. Of the 49 patients with metastatic disease and medically resistant ectopic Cushing syndrome, 23 ultimately had bilateral adrenalectomy with ectopic Cushing syndrome cure in all. CONCLUSION: Patients with neuroendocrine tumors before ectopic Cushing syndrome development were more likely metastatic and had worse survival. De novo hyperglycemia and poor neuroendocrine tumor differentiation were predictive of worse prognosis. Medical control of hypercortisolism is difficult to achieve in patients with neuroendocrine tumors-ectopic Cushing syndrome. Well-selected patients may benefit from bilateral adrenalectomy early in the treatment algorithm, and multidisciplinary management is essential in this complex disease.


Assuntos
Síndrome de ACTH Ectópico , Síndrome de Cushing , Hiperglicemia , Tumores Neuroendócrinos , Síndrome de ACTH Ectópico/complicações , Síndrome de ACTH Ectópico/diagnóstico , Adrenalectomia/efeitos adversos , Hormônio Adrenocorticotrópico , Síndrome de Cushing/diagnóstico , Síndrome de Cushing/etiologia , Síndrome de Cushing/cirurgia , Humanos , Hiperglicemia/complicações , Tumores Neuroendócrinos/complicações , Tumores Neuroendócrinos/cirurgia , Estudos Retrospectivos
3.
Lab Invest ; 102(6): 658-666, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35228656

RESUMO

Undifferentiated pleomorphic sarcoma (UPS) and malignant peripheral nerve sheath tumor (MPNST) are aggressive soft tissue sarcomas that do not respond well to current treatment modalities. The limited availability of UPS and MPNST cell lines makes it challenging to identify potential therapeutic targets in a laboratory setting. Understanding the urgent need for improved treatments for these tumors and the limited cellular models available, we generated additional cell lines to study these rare cancers. Patient-derived tumors were used to establish 4 new UPS models, including one radiation-associated UPS-UPS271.1, UPS511, UPS0103, and RIS620, one unclassified spindle cell sarcoma-USC060.1, and 3 new models of MPNST-MPNST007, MPNST3813E, and MPNST4970. This study examined the utility of the new cell lines as sarcoma models by assessing their tumorigenic potential and mutation status for known sarcoma-related genes. All the cell lines formed colonies and migrated in vitro. The in vivo tumorigenic potential of the cell lines and corresponding xenografts was determined by subcutaneous injection or xenograft re-passaging into immunocompromised mice. USC060.1 and UPS511 cells formed tumors in mice upon subcutaneous injection. UPS0103 and RIS620 tumor implants formed tumors in vivo, as did MPNST007 and MPNST3813E tumor implants. Targeted sequencing analysis of a panel of genes frequently mutated in sarcomas identified TP53, RB1, and ATRX mutations in a subset of the cell lines. These new cellular models provide the scientific community with powerful tools for detailed studies of tumorigenesis and for investigating novel therapies for UPS and MPNST.


Assuntos
Neurofibrossarcoma , Sarcoma , Neoplasias de Tecidos Moles , Animais , Humanos , Camundongos , Modelos Teóricos , Mutação , Neurofibrossarcoma/genética , Sarcoma/genética , Sarcoma/patologia , Neoplasias de Tecidos Moles/genética
4.
Surgery ; 171(5): 1240-1246, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-34952716

RESUMO

BACKGROUND: Postoperative hypoparathyroidism from inadequate parathyroid hormone is of concern after multigland resections in multiple endocrine neoplasia type 1-related primary hyperparathyroidism. We evaluated risk factors, long-term outcomes, and roles of autotransplantation and cryopreservation in postoperative hypoparathyroidism in multiple endocrine neoplasia type 1. METHODS: Retrospective cohort study of patients with multiple endocrine neoplasia type 1 and parathyroidectomy who were evaluated at MD Anderson from 1990 to 2020. RESULTS: We included 206 patients. Median follow-up after the last operation (index 65%, reoperation 35%) was 8 years. Index parathyroidectomy was subtotal in 47%, less than subtotal in 42%, and total in 12%; hypoparathyroidism was more frequent after total parathyroidectomy. Forty-seven patients (23%) had hypoparathyroidism ≥6 months; odds were significantly higher when cumulative ≥4 glands were resected (odds ratio 6 [2.96-12.24]) or when immediate postoperative parathyroid hormone was <15 pg/mL (odds ratio 13.10 [3.61-47.47]). After median 26 months postoperatively, 30% recovered parathyroid function spontaneously; this was less likely when ≥4 glands were resected (odds ratio 0.19 [0.05-0.72]). None of the 4 patients who were aparathyroid (parathyroid hormone undetectable or ≤3 pg/mL) at 6 months postoperatively recovered parathyroid function. Immediate autotransplantation success rate was 72%. Cryopreservation was performed in 96 operations with delayed autotransplantation in 10 patients (10% utilization), of whom 5 recovered parathyroid function (time to recovery 12-93 months). CONCLUSION: Odds of prolonged hypoparathyroidism are higher when cumulative ≥4 glands are resected or postoperative parathyroid hormone is <15 pg/mL. Spontaneous recovery occurred but was less likely when ≥4 glands were resected or patients were aparathyroid at 6 months postoperatively. Cryopreservation should be sparingly used, but there is value in select high-risk patients such as reoperative parathyroidectomy/cervical surgery.


Assuntos
Hipoparatireoidismo , Neoplasia Endócrina Múltipla Tipo 1 , Humanos , Hipoparatireoidismo/etiologia , Hipoparatireoidismo/prevenção & controle , Neoplasia Endócrina Múltipla Tipo 1/complicações , Neoplasia Endócrina Múltipla Tipo 1/cirurgia , Recidiva Local de Neoplasia/cirurgia , Glândulas Paratireoides/transplante , Hormônio Paratireóideo , Paratireoidectomia/efeitos adversos , Estudos Retrospectivos , Fatores de Risco , Transplante Autólogo/efeitos adversos
5.
Acta Neuropathol ; 142(3): 565-590, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34283254

RESUMO

Malignant peripheral nerve sheath tumors (MPNSTs) are soft tissue sarcomas that frequently harbor genetic alterations in polycomb repressor complex 2 (PRC2) components-SUZ12 and EED. Here, we show that PRC2 loss confers a dedifferentiated early neural-crest phenotype which is exclusive to PRC2-mutant MPNSTs and not a feature of neurofibromas. Neural crest phenotype in PRC2 mutant MPNSTs was validated via cross-species comparative analysis using spontaneous and transgenic MPNST models. Systematic chromatin state profiling of the MPNST cells showed extensive epigenomic reprogramming or chromatin states associated with PRC2 loss and identified gains of active enhancer states/super-enhancers on early neural crest regulators in PRC2-mutant conditions around genomic loci that harbored repressed/poised states in PRC2-WT MPNST cells. Consistently, inverse correlation between H3K27me3 loss and H3K27Ac gain was noted in MPNSTs. Epigenetic editing experiments established functional roles for enhancer gains on DLX5-a key regulator of neural crest phenotype. Consistently, blockade of enhancer activity by bromodomain inhibitors specifically suppressed this neural crest phenotype and tumor burden in PRC2-mutant PDXs. Together, these findings reveal accumulation of dedifferentiated neural crest like state in PRC2-mutant MPNSTs that can be targeted by enhancer blockade.


Assuntos
Neoplasias de Bainha Neural/tratamento farmacológico , Neoplasias de Bainha Neural/genética , Neoplasias do Sistema Nervoso Periférico/tratamento farmacológico , Neoplasias do Sistema Nervoso Periférico/genética , Complexo Repressor Polycomb 2/genética , Animais , Biomarcadores Tumorais , Proteínas de Ciclo Celular/antagonistas & inibidores , Diferenciação Celular/genética , Linhagem Celular Tumoral , Cães , Elementos Facilitadores Genéticos/genética , Epigênese Genética/genética , Proteínas de Homeodomínio/genética , Humanos , Camundongos , Camundongos Transgênicos , Mutação , Neoplasias de Bainha Neural/patologia , Crista Neural/patologia , Neoplasias do Sistema Nervoso Periférico/patologia , Especificidade da Espécie , Fatores de Transcrição/antagonistas & inibidores , Fatores de Transcrição/genética , Ensaios Antitumorais Modelo de Xenoenxerto , Peixe-Zebra
6.
JAMA Netw Open ; 4(3): e210945, 2021 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-33734413

RESUMO

Importance: Neurofibromatosis type 1 (NF1) is a complex genetic disorder that is associated with not only neurofibromas, but also an increased susceptibility to other neoplasms. Objective: To evaluate the prevalence of neoplasia and outcomes among patients with NF1. Design, Setting, and Participants: This cohort study was conducted among patients with NF1 at a single academic cancer center from 1985 to 2020 with median (range) follow-up of 2.9 years (36 days to 30.5 years). Of 2427 patients evaluated for NF1, 1607 patients who met the National Institutes of Health consensus criteria for NF1 were included. This group was compared with estimates from Surveillance, Epidemiology, and End Results (SEER) Cancer Statistics Review 1975 to 2015 and SEER participants database unless otherwise specified. Data were analyzed from August 2018 to March 2020. Main Outcomes and Measures: Disease-specific survival (DSS) was measured from diagnosis date to date of neoplasm-specific death or censorship and calculated using the Kaplan-Meier method. Survival curves were compared using the log-rank test. Deaths from disease were considered a DSS end point; other deaths were considered censored observations. Secondary outcome measures were comparisons of (1) overall survival of patients with NF1 with neurofibroma neoplasms vs those without nonneurofibroma neoplasms, (2) neoplasm prevalence in the NF1 group vs general population estimates, and (3) age at diagnosis in the NF1 group vs general population estimates for the most common neoplasms in the NF1 group. Results: Among 1607 patients with NF1, the median (range) age at initial visit was 19 years (1 month to 83 years) and 840 (52.3%) were female patients. Among 666 patients who developed other neoplasms in addition to neurofibromas (41.4%), 295 patients (18.4%) developed glioma and 243 patients (15.1%) developed malignant peripheral nerve sheath tumor (MPNST), the most common neoplasms. Patients with NF1, compared with the general population, developed several neoplasms at a younger mean (SD) age (low-grade glioma: 12.98 [11.09] years vs 37.76 [24.53] years; P < .0001; high-grade glioma [HGG]: 27.31 [15.59] years vs 58.42 [19.09] years; P < .0001; MPNST: 33.88 [14.80] years vs 47.06 [20.76] years; P < .0001; breast cancer: 46.61 [9.94] years vs 61.71 [13.85] years; P < .0001). Patients with NF1 developed neoplasms more frequently compared with the general population (odds ratio, 9.5; 95% CI, 8.5-10.5; P < .0001). Among patients with NF1, significantly lower 5-year DSS rates were found among those with undifferentiated pleomorphic sarcoma (1 of 5 patients [20.0%]), HGG (8 of 34 patients [23.1%]), MPNST (72 of 228 patients [31.6%]), ovarian carcinoma (4 of 7 patients [57.1%]), and melanoma (8 of 12 patients [66.7%]) compared with those who had neoplasms classified as other (110 of 119 patients [92.4%]) (all P < .001) . Conclusions and Relevance: This cohort study found that among patients with NF1, those who developed undifferentiated pleomorphic sarcoma, HGG, MPNST, ovarian carcinoma, or melanoma had significantly lower DSS rates compared with those who developed other neoplasms. This study also found that patients with NF1 developed some neoplasms more frequently and at a younger age compared with individuals without NF1. HGGs and MPNST were noteworthy causes of death among patients NF1. This information may be useful for NF1 patient counseling and follow-up.


Assuntos
Neoplasias Primárias Múltiplas/epidemiologia , Neoplasias/epidemiologia , Neurofibromatose 1/epidemiologia , Centros Médicos Acadêmicos , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Estudos de Coortes , Feminino , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Prevalência , Fatores de Tempo , Adulto Jovem
7.
Surgery ; 169(1): 175-184, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-32703679

RESUMO

BACKGROUND: It is unclear whether genotype-negative clinical multiple endocrine neoplasia type 1 patients derive equal benefit from prospective surveillance as genotype-positive patients. METHODS: In this retrospective cohort study, we compared genotype-negative patients with clinical multiple endocrine neoplasia type 1 with genotype-positive index cases. Primary outcome was age-related penetrance of manifestations; secondary outcomes were disease-specific survival and clinical course of endocrine tumors. RESULTS: We included 39 genotype-negative patients with clinical multiple endocrine neoplasia type 1 (Male: 33%) and 63 genotype-positive multiple endocrine neoplasia type 1 index cases (Male: 59%). Genotype-negative patients with clinical multiple endocrine neoplasia type 1 were 65 years old at last follow-up; genotype-positive multiple endocrine neoplasia type 1 index cases were 50 (P < .001). Genotype-negative patients with clinical multiple endocrine neoplasia type 1 were significantly older at their first and second primary manifestation. Only 1 developed a third primary manifestation. No genotype-negative patients with clinical multiple endocrine neoplasia type 1 with primary hyperparathyroidism and a pituitary adenoma developed a duodenopancreatic neuroendocrine tumor. Disease-specific survival was significantly better in genotype-negative patients with clinical multiple endocrine neoplasia type 1. In genotype-negative patients with clinical multiple endocrine neoplasia type 1, primary hyperparathyroidism was single-gland disease in 47% of parathyroidectomies versus 0% in genotype-positive multiple endocrine neoplasia type 1 index cases. In genotype-negative patients with clinical multiple endocrine neoplasia type 1, 17% of duodenopancreatic neuroendocrine tumors were multifocal versus 68% in genotype-positive multiple endocrine neoplasia type 1 index cases. Genotype-negative patients with clinical multiple endocrine neoplasia type 1 had more pituitary macroadenomas, fewer prolactinomas, and more somatotroph adenomas. CONCLUSION: Genotype-negative patients with clinical multiple endocrine neoplasia type 1 have a different clinical course than genotype-positive multiple endocrine neoplasia type 1 index cases. This may support a separate classification and a tailored surveillance regimen. Of the genotype-negative patients with clinical multiple endocrine neoplasia type 1 who had parathyroidectomy, almost half had no evidence of multigland disease and may be potential candidates for a more targeted single-gland approach.


Assuntos
Hiperparatireoidismo Primário/epidemiologia , Neoplasia Endócrina Múltipla Tipo 1/terapia , Tumores Neuroendócrinos/epidemiologia , Neoplasias Pancreáticas/epidemiologia , Neoplasias Hipofisárias/epidemiologia , Adulto , Fatores Etários , Idoso , Feminino , Seguimentos , Testes Genéticos/estatística & dados numéricos , Genótipo , Humanos , Hiperparatireoidismo Primário/genética , Hiperparatireoidismo Primário/terapia , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Neoplasia Endócrina Múltipla Tipo 1/complicações , Neoplasia Endócrina Múltipla Tipo 1/genética , Neoplasia Endócrina Múltipla Tipo 1/mortalidade , Tumores Neuroendócrinos/genética , Tumores Neuroendócrinos/terapia , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/terapia , Paratireoidectomia/estatística & dados numéricos , Neoplasias Hipofisárias/genética , Neoplasias Hipofisárias/terapia , Proteínas Proto-Oncogênicas/genética , Estudos Retrospectivos , Fatores de Risco , Conduta Expectante
8.
Ann Surg Oncol ; 28(2): 751-757, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32691337

RESUMO

BACKGROUND: Appendiceal neuroendocrine tumors (ANETs) are rare neoplasms usually discovered incidentally during appendectomy. ANETs < 2 cm were thought to have no metastatic potential, and this dogma has driven management. Our aim is to evaluate the metastatic potential of ANETs < 2 cm. PATIENTS AND METHODS: A retrospective review was performed in a series of patients with ANETs who presented to our tertiary referral center from 1998 to 2019. Demographics, tumor characteristics, treatment, and clinical outcomes were evaluated. RESULTS: In total, 114 patients were included. Median follow-up was 3.3 years (range, 21 days-15 years). At last follow-up, 34 (30%) patients had positive regional lymph nodes and 20 (18%) patients had metastatic disease. Of the 20 patients with metastatic disease, 11 (55%) had primary ANETs < 2 cm. Patient age > 40 years at diagnosis and ANETs with serosal invasion, lymphovascular invasion, intermediate tumor grade, or positive lymph nodes were features significantly more likely to present with metastatic disease. We found no difference in the rate of lymph node positivity, metastatic disease, or overall survival when patients were stratified by tumor size or type of resection (appendectomy vs. right hemicolectomy). On multivariate analysis, patients with metastatic disease at diagnosis had worse overall survival (HR = 24.4, p = 0.008). CONCLUSIONS: In our cohort, tumor size was not a significant risk factor for metastatic disease or worse outcome as many patients with ANETs < 2 cm developed metastatic disease. Appendectomy alone was sufficient surgical management for most ANETs. Patients with risk factors for metastatic disease, regardless of primary ANET size, should be evaluated thoroughly and counseled for further management and surveillance.


Assuntos
Neoplasias do Apêndice , Tumores Neuroendócrinos , Adulto , Apendicectomia , Neoplasias do Apêndice/cirurgia , Humanos , Linfonodos , Tumores Neuroendócrinos/cirurgia , Estudos Retrospectivos
9.
Cancer ; 126(14): 3265-3273, 2020 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-32343846

RESUMO

BACKGROUND: The objective of this study was to evaluate treatment outcomes for patients with desmoid tumors (DTs) receiving local therapy with surgery alone, radiation therapy (RT) alone, or combined modality therapy (RT and surgery). METHODS: This was a cross-sectional cohort study of 412 patients with nonmesenteric DTs who received local therapy at the authors' institution between 1965 and 2018. RESULTS: The median follow-up time was 95 months (range, 1-509 months). Local recurrence occurred in 127 patients (31%) at a median time of 21 months (interquartile range, 12-38 months). The 5-year local control (LC) rate was 67%. Patient or tumor factors that were significantly associated with poorer 5-year LC in a multivariable analysis included an age ≤ 30 years (57% vs 75% for an age > 30 years; hazard ratio [HR], 1.73; P = .004), an extremity location (57% vs 71% for a nonextremity location; HR, 1.77; P = .004), and large tumors (59% for >10 cm [HR, 2.17; P = .004] and 65% for 5.1-10 cm [HR, 1.71; P = .02] vs 76% for ≤5 cm). Subset analyses of these high-risk patients revealed no local therapy strategy to be superior for young patients ≤ 30 years old (HR for surgery, 1.42; P = .33; HR for RT, 1.36; P = .38) or for large tumors > 10 cm (HR for surgery, 1.55; P = .46; HR for RT, 0.91; P = .91). However, for patients with extremity tumors, surgery alone was significantly associated with inferior LC (HR for surgery, 5.15; P < .001; HR for RT, 1.51; P = .38). CONCLUSIONS: Local therapy provides durable tumor control in the majority of patients with DTs. However, young patients, patients with an extremity location, and patients with large tumors are at increased risk of recurrence. When active treatment is indicated, systemic therapy should perhaps be considered as a first-line option in these high-risk subsets. Prospective multi-institutional studies evaluating this strategy are warranted.


Assuntos
Extremidades/patologia , Fibromatose Agressiva/radioterapia , Fibromatose Agressiva/cirurgia , Neoplasias de Cabeça e Pescoço/radioterapia , Neoplasias de Cabeça e Pescoço/cirurgia , Tronco/patologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Terapia Combinada/métodos , Estudos Transversais , Feminino , Fibromatose Agressiva/epidemiologia , Fibromatose Agressiva/mortalidade , Seguimentos , Neoplasias de Cabeça e Pescoço/epidemiologia , Neoplasias de Cabeça e Pescoço/mortalidade , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Recidiva Local de Neoplasia , Estudos Retrospectivos , Fatores de Risco , Taxa de Sobrevida , Texas/epidemiologia , Resultado do Tratamento , Adulto Jovem
10.
J Biomater Appl ; 28(7): 1028-38, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23775239

RESUMO

Herein we report a facile layer-by-layer method for creating an antimicrobial coating composed of silver nanoparticles on medical grade titanium test discs. Nanoscale silver nanoparticle layers are attached to the titanium orthopedic implant material via aminopropyltriethoxy silane crosslinker that reacts with neighboring silane moieties to create an interconnected network. A monolayer of silane, followed by a monolayer of silver nanoparticles would form one self-assembled layer and this process can be repeated serially, resulting in increased silver nanoparticles deposition. The release rate of silver ion increases predictably with increasing numbers of layers and at appropriate thicknesses these coatings demonstrate 3-4 log reduction of viable Escherichia coli and Staphylococcus aureus bacteria. Increasing the thickness of the coatings resulted in reduced bacterial colonization as determined by fluorescent staining and image analysis. Interestingly, the cytotoxicity of murine 3T3 cells as quantified by fluorescent staining and flow cytometry, was minimal and did not vary significantly with the coating thickness. Additionally, these coatings are mechanically stable and resist delamination by orthogonal stress test. This simple layer-by-layer coating technique may provide a cost-effective and biocompatible method for reducing microbial colonization of implantable orthopedic devices.


Assuntos
Infecções Bacterianas/prevenção & controle , Sobrevivência Celular , Materiais Revestidos Biocompatíveis , Nanopartículas Metálicas/química , Prata/química , Células 3T3 , Animais , Aderência Bacteriana , Infecções Bacterianas/microbiologia , Escherichia coli/isolamento & purificação , Técnicas In Vitro , Camundongos , Testes de Sensibilidade Microbiana , Microscopia Eletrônica de Varredura , Espectrofotometria Ultravioleta , Staphylococcus aureus/isolamento & purificação , Ressonância de Plasmônio de Superfície , Resistência à Tração
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