RESUMO
The number of elderly patients with esophageal cancer has increased in recent years. The use of thoracoscopic esophagectomy has also increased, and its minimal invasiveness is believed to contribute to postoperative outcomes. However, the short- and long-term outcomes in elderly patients remain unclear. This study aimed to elucidate the safety and feasibility of minimally invasive esophagectomy in elderly patients. This retrospective study included 207 patients who underwent radical thoracoscopic esophagectomy for thoracic esophageal squamous cell carcinoma at Kobe University Hospital between 2005 and 2014. Patients were divided into non-elderly (<75 years) and elderly (≥75 years) groups. A propensity score matching analysis was performed for sex and clinical T and N stage, with a total of 29 matched pairs. General preoperative data, surgical procedures, intraoperative data, postoperative complications, in-hospital death, cancer-specific survival, and overall survival were compared between groups. The elderly group was characterized by lower preoperative serum albumin levels and higher American Society of Anesthesiologists grade. Intraoperative data and postoperative complications did not differ between the groups. The in-hospital death rate was 4% in the elderly group, which did not significantly differ from the non-elderly group. Cancer-specific survival was similar between the two groups. Although overall survival tended to be poor in the elderly group, it was not significantly worse than that of the non-elderly group. In conclusion, the short- and long-term outcomes of minimally invasive esophagectomy in elderly versus non-elderly patients were acceptable. Minimally invasive esophagectomy is a safe and feasible modality for elderly patients with appropriate indications.
Assuntos
Neoplasias Esofágicas , Carcinoma de Células Escamosas do Esôfago , Idoso , Neoplasias Esofágicas/cirurgia , Carcinoma de Células Escamosas do Esôfago/cirurgia , Esofagectomia/efeitos adversos , Estudos de Viabilidade , Mortalidade Hospitalar , Humanos , Pessoa de Meia-Idade , Procedimentos Cirúrgicos Minimamente Invasivos , Complicações Pós-Operatórias/epidemiologia , Complicações Pós-Operatórias/etiologia , Estudos Retrospectivos , Resultado do TratamentoRESUMO
C-reactive protein to albumin (CRP/Alb) ratio, a novel inflammation-based prognostic score, was first developed as a prognostic score for septic patients. Recent reports show that CRP/Alb ratio is also a prognostic score for cancer patients, including esophageal cancer. However, the role of CRP/Alb ratio for those with neoadjuvant chemotherapy (NAC) and the changes of CRP/Alb ratio around NAC have never been discussed. The aim of this study is to evaluate the significance of CRP/Alb ratio around NAC for patients with cStage II/III esophageal squamous cell cancer (ESCC). A total of 149 patients who were diagnosed as cStage II/III ESCC were enrolled between February 2007 and December 2014. We retrospectively investigated the relation between pre-NAC and post-NAC CRP/Alb ratio and short and long outcomes. The optimal cutoff level for pre-NAC and post-NAC CRP/Alb ratio was 0.030 and 0.048, respectively. There was no relation between CRP/Alb ratio level and postoperative outcomes. Post-NAC CRP/Alb ratio < 0.048 had a significantly higher overall survival rate than CRP/Alb ratio ≥0.048 (P< 0.001). Univariate analysis showed that cT, cN, pre-NAC CRP/Alb ratio < 0.030 and post-NAC CRP/Alb ratio < 0.048 was prognostic factors (P= 0.003, P= 0.022, P= 0.033, and P< 0.001, respectively). Multivariate analysis showed that cT and post-NAC CRP/Alb ratio < 0.048 was independent prognostic factors (P= 0.030 and P< 0.001, respectively). Post-NAC CRP/Alb ratio is an independent prognostic factor in patients with cStage II/III ESCC.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Proteína C-Reativa/metabolismo , Carcinoma de Células Escamosas/sangue , Carcinoma de Células Escamosas/terapia , Neoplasias Esofágicas/sangue , Neoplasias Esofágicas/terapia , Albumina Sérica/metabolismo , Idoso , Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Proteína C-Reativa/efeitos dos fármacos , Carcinoma de Células Escamosas/secundário , Quimioterapia Adjuvante , Cisplatino/administração & dosagem , Neoplasias Esofágicas/patologia , Esofagectomia , Feminino , Fluoruracila/administração & dosagem , Humanos , Masculino , Pessoa de Meia-Idade , Terapia Neoadjuvante , Estadiamento de Neoplasias , Prognóstico , Estudos Retrospectivos , Albumina Sérica/efeitos dos fármacos , Taxa de SobrevidaRESUMO
Aortoesophageal fistula is a critical and life-threatening disease. The cardiovascular strategy for graft replacement has been widely discussed. However, the surgical strategy of esophageal resection and reconstruction for aortoesophageal fistula has rarely been discussed. The objective of this study is to establish a surgical strategy and procedure of esophageal resection and reconstruction for aortoesophageal fistula. Eleven patients with aortoesophageal fistula who underwent aortic graft replacement and esophagectomy between 2008 and 2015 at Kobe University Hospital were enrolled in this study. Patient characteristics, operative methods, and clinical outcomes were obtained by retrospective chart review. All 11 patients underwent graft replacement, esophagectomy, and omental wrapping. Ten esophagectomies were simultaneously accomplished in the same operative field as aortic graft replacement. Seven patients underwent subtotal esophagectomy from a left thoracotomy, and three patients underwent upper hemiesophagectomy from a median sternotomy. The other patient underwent staged esophagectomy from a right thoracotomy. Seven of 11 patients (63.6%) successfully underwent staged esophageal reconstruction. Pedicled jejunal transfer with supercharge and superdrainage were performed in six patients, and ileocecal reconstruction was performed in one patient. Median survival time in the patients with esophageal reconstruction was 21 months while that in the patients without esophageal reconstruction was 10 months. Six of 7 patients (85.7%) who underwent esophageal reconstructions were alive. Our surgical strategy for aortoesophageal fistula, which includes simultaneous graft replacement and esophagectomy in the same operative field and staged reconstruction by pedicled jejunal transfer to ensure omental wrapping, is feasible and promising.
Assuntos
Doenças da Aorta/cirurgia , Fístula Esofágica/cirurgia , Esofagectomia/métodos , Procedimentos de Cirurgia Plástica/métodos , Fístula Vascular/cirurgia , Adulto , Idoso , Idoso de 80 Anos ou mais , Ceco/transplante , Feminino , Humanos , Íleo/transplante , Jejuno/transplante , Masculino , Pessoa de Meia-Idade , Omento/transplante , Estudos Retrospectivos , Esternotomia , Taxa de Sobrevida , Toracotomia , Enxerto Vascular , Procedimentos Cirúrgicos Vasculares/métodosAssuntos
Coristoma/diagnóstico , Obstrução da Saída Gástrica/diagnóstico por imagem , Obstrução da Saída Gástrica/etiologia , Pâncreas , Síndrome de Peutz-Jeghers/complicações , Síndrome de Peutz-Jeghers/diagnóstico por imagem , Complicações na Gravidez , Gastropatias/diagnóstico , Neoplasias Gástricas/complicações , Neoplasias Gástricas/diagnóstico por imagem , Adulto , Endoscopia do Sistema Digestório , Endossonografia , Feminino , Gastrectomia/métodos , Humanos , Laparoscopia/métodos , Síndrome de Peutz-Jeghers/patologia , Síndrome de Peutz-Jeghers/cirurgia , Gravidez , Antro Pilórico , Neoplasias Gástricas/patologia , Neoplasias Gástricas/cirurgiaRESUMO
Tom20 is a major receptor of the mitochondrial preprotein translocation system and is bound to the outer membrane through the NH(2)-terminal transmembrane domain (TMD) in an Nin-Ccyt orientation. We analyzed the mitochondria-targeting signal of rat Tom20 (rTom20) in COS-7 cells, using green fluorescent protein (GFP) as the reporter by systematically introducing deletions or mutations into the TMD or the flanking regions. Moderate TMD hydrophobicity and a net positive charge within five residues of the COOH-terminal flanking region were both critical for mitochondria targeting. Constructs without net positive charges within the flanking region, as well as those with high TMD hydrophobicity, were targeted to the ER-Golgi compartments. Intracellular localization of rTom20-GFP fusions, determined by fluorescence microscopy, was further verified by cell fractionation. The signal recognition particle (SRP)-induced translation arrest and photo-cross-linking demonstrated that SRP recognized the TMD of rTom20-GFP, but with reduced affinity, while the positive charge at the COOH-terminal flanking segment inhibited the translation arrest. The mitochondria-targeting signal identified in vivo also functioned in the in vitro system. We conclude that NH(2)-terminal TMD with a moderate hydrophobicity and a net positive charge in the COOH-terminal flanking region function as the mitochondria-targeting signal of the outer membrane proteins, evading SRP-dependent ER targeting.
Assuntos
Membranas Intracelulares/metabolismo , Proteínas de Membrana/metabolismo , Proteínas de Membrana Transportadoras , Mitocôndrias/metabolismo , Sinais Direcionadores de Proteínas , Receptores de Superfície Celular , Sequência de Aminoácidos , Animais , Transporte Biológico , Células COS , Compartimento Celular , Cisteína Endopeptidases/efeitos dos fármacos , Inibidores de Cisteína Proteinase/farmacologia , Retículo Endoplasmático/metabolismo , Complexo de Golgi/metabolismo , Proteínas de Fluorescência Verde , Proteínas Luminescentes/genética , Proteínas Luminescentes/metabolismo , Proteínas de Membrana/genética , Proteínas do Complexo de Importação de Proteína Precursora Mitocondrial , Dados de Sequência Molecular , Complexos Multienzimáticos/efeitos dos fármacos , Complexo de Endopeptidases do Proteassoma , Estrutura Terciária de Proteína , Ratos , Proteínas Recombinantes de Fusão/metabolismo , Partícula de Reconhecimento de Sinal/metabolismoRESUMO
Essentials Reduced survival of von Willebrand factor (VWF) in plasma causes type 1C von Willebrand disease. Blood was collected from mouse strains by various methods and VWF propeptide and antigen assayed. VWF propeptide to antigen ratio identifies a reduced VWF survival phenotype in mice. This ratio validates the acceptability of murine blood samples for coagulation studies. SUMMARY: Background Reduced plasma survival of von Willebrand factor (VWF) is characteristic of patients with type 1C von Willebrand disease (VWD). These subjects can be identified by an increased steady-state ratio of plasma VWF propeptide (VWFpp) to VWF antigen (VWF:Ag). A similar phenotype occurs in mice with the Mvwf1 allele. Objectives To (i) determine if the VWFpp/VWF:Ag ratio can be used to identify a 'type 1C' phenotype in mice, (ii) determine the most reliable method for murine blood sampling, and (iii) identify the source of VWF released during problematic blood collection. Methods 'Platelet-VWF' and 'endothelial-VWF' mice were generated by bone marrow transplantation between C57BL/6J and VWF-/- mice. Several blood sampling methods were used and murine VWFpp and VWF:Ag levels determined. Plasma and platelet VWF:Ag and VWFpp, VWF multimers and VWF half-life were examined in mouse strains with and without Mvwf1. Results A single retro-orbital bleed and vena cava collection were found to be the optimal methods of blood collection. Problematic collection resulted in release of VWF from platelets and endothelium. The VWFpp/VWF:Ag ratio identified strains of mice with reduced VWF survival. Conclusion Assay of murine VWFpp and VWF:Ag has utility in determining the acceptability of murine blood samples for coagulation testing and in identification of a reduced VWF survival phenotype in mice.
Assuntos
Peptídeos/química , Ativação Plaquetária , Doenças de von Willebrand/genética , Fator de von Willebrand/química , Alelos , Animais , Antígenos/química , Coagulação Sanguínea , Plaquetas/citologia , Transplante de Medula Óssea , Modelos Animais de Doenças , Células HEK293 , Hemorragia , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Fenótipo , Flebotomia , Precursores de Proteínas/sangue , Reprodutibilidade dos Testes , Veia SafenaRESUMO
The incidence of allergic diseases has dramatically increased in recent decades, especially in urban and industrialized areas. It is important socially as well as medically to establish more useful strategies to overcome allergic disorders. Bronchial asthma is a complex disease characterized by airway inflammation involving a Th2-cytokine, interleukin (IL)-13. A substantial body of evidence has accumulated pointing to the pivotal role of IL-13 in the pathogenesis of bronchial asthma, based on mainly analyses of mouse models. In addition to such analyses, the high expression of IL-13 in lesions and genetic association of several genes coding IL-13 signaling molecules with bronchial asthma have raised the possibility that IL-13 plays a pivotal role in the onset or exacerbation of human bronchial asthma. Therefore, IL-13 and its signal pathway are thought to be promising targets to develop a therapeutic agent for bronchial asthma. In this article, we describe how IL-13 is involved in the pathogenesis of bronchial asthma and then how therapeutic agents to block IL-13 signals are developed for bronchial asthma.
Assuntos
Asma/tratamento farmacológico , Interleucina-13/uso terapêutico , Asma/imunologia , Humanos , Interleucina-13/genética , Receptores de Interleucina-1/fisiologiaRESUMO
BACKGROUND: Enhancements in surgical techniques have led to improved outcomes for esophageal cancer. Recent findings have showed that esophageal cancer is frequently associated with multiple primary cancers, and surgical resection is usually complicated in such cases. The aim of this study was to clarify the clinical significance of surgery for patients with esophageal squamous cell cancer associated with multiple primary cancers. METHODS: The clinical outcomes of surgical resection for esophageal cancer were compared among 79 patients with antecedent and/or synchronous cancers (Multiple cancer group) and 194 patients without antecedent and/or synchronous cancers (Single cancer group). RESULTS: The most common site of multiple primary cancers was the pharynx (36 patients; 29.7%), followed by the stomach (24 patients; 19.8%). The reconstruction method was more complicated in the Multiple cancer group as a result of the prolonged surgery time and increased blood loss. However, postoperative morbidity and overall survival (OS) did not differ between the two groups. After esophagectomy, metachronous cancers were observed in 26 patients, with 30 regions in total, and 93.1% were found to be curable. Sex was the only independent risk factors for developing metachronous cancer after esophagectomy. CONCLUSIONS: The presence of antecedent and synchronous cancers complicates the surgical resection of esophageal cancer; however, no differences were found in the OS and postoperative morbidity between the two groups. Therefore, surgical intervention should be selected as a first-line treatment. Because second primary cancers are often observed in esophageal cancer, we recommend a close follow-up using esophagogastroduodenoscopy and contrast-enhanced computed tomography.
Assuntos
Carcinoma de Células Escamosas/patologia , Carcinoma de Células Escamosas/cirurgia , Neoplasias Esofágicas/patologia , Neoplasias Esofágicas/cirurgia , Recidiva Local de Neoplasia/patologia , Neoplasias Primárias Múltiplas/cirurgia , Idoso , Carcinoma de Células Escamosas/mortalidade , Distribuição de Qui-Quadrado , Estudos de Coortes , Intervalo Livre de Doença , Neoplasias Esofágicas/mortalidade , Esofagectomia/métodos , Esofagectomia/mortalidade , Feminino , Humanos , Japão , Estimativa de Kaplan-Meier , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Invasividade Neoplásica/patologia , Recidiva Local de Neoplasia/mortalidade , Estadiamento de Neoplasias , Neoplasias Primárias Múltiplas/mortalidade , Neoplasias Primárias Múltiplas/patologia , Segurança do Paciente , Prognóstico , Estudos Retrospectivos , Medição de Risco , Análise de Sobrevida , Resultado do TratamentoRESUMO
The factor XII genes of two unrelated factor XII-deficient Japanese families were screened, and two novel mutations were identified. A heterozygous mutation (Q421K) was identified in the gene of a cross-reacting material (CRM)-negative patient with reduced FXII activity (entitled Case 1). No mutations were discovered in the other allele. Case 2 was a CRM-negative patient with severe FXII deficiency. In this case, a homozygous mutation (R123P) was discerned. Expression studies in Chinese Hamster Ovary (CHO) cells demonstrated accumulation of mutant Q421 K factor XII in the cell, and insufficient secretion, while the R123P mutant showed lower levels of accumulation than wild-type, and no evidence of secretion in culture supernatant. In the presence of proteasome inhibitor, all types of FXII (wild-type. Q421K, R123P) accumulated in the cells. Protease protection experiments using the microsomal fraction of these cell lines demonstrated that while 20% wild-type FXII (total wild-type:100%) and 10% R123P mutant (total R123P-type: 40%) were resistant to treatment with trypsin, 50% Q421K-type FXII (total Q421K-type:130%) remained resistant to digestion. From these results, we conclude that Q421K is less susceptible to proteasome degradation than wild-type, but is unable to exit the ER efficiently, resulting in insufficient secretion phenotype. In contrast, R123P is susceptible to proteasome degradation and is not secreted.
Assuntos
Acetilcisteína/análogos & derivados , Substituição de Aminoácidos , Deficiência do Fator XII/genética , Fator XII/genética , Mutação de Sentido Incorreto , Mutação Puntual , Acetilcisteína/farmacologia , Adolescente , Animais , Brefeldina A/farmacologia , Células CHO , Códon/genética , Cricetinae , Cricetulus , Cisteína Endopeptidases/metabolismo , Análise Mutacional de DNA , Éxons/genética , Fator XII/análise , Fator XII/metabolismo , Heterozigoto , Homozigoto , Humanos , Masculino , Pessoa de Meia-Idade , Complexos Multienzimáticos/antagonistas & inibidores , Complexos Multienzimáticos/metabolismo , Tempo de Tromboplastina Parcial , Linhagem , Reação em Cadeia da Polimerase , Inibidores de Proteases/farmacologia , Complexo de Endopeptidases do Proteassoma , Proteínas Recombinantes de Fusão/metabolismo , TransfecçãoRESUMO
BACKGROUND: Bernard-Soulier syndrome (BSS) is an inherited bleeding disorder characterized by macrothrombocytopenia. Platelet transfusion is used for the management of bleeding, but repeated transfusion often results in alloimmunization. We have recently shown phenotypic correction of murine BSS (GPIbα(null) ) using lethal radiation conditioning followed by hematopoietic lentivirus-mediated gene transfer. OBJECTIVES: For application of gene therapy to treatment of human patients, it is important to minimize treatment-related side effects. The objective of this study is to model a clinically relevant non-myeloablative hematopoietic stem cell (HSC) transplantation strategy. METHODS: Using transplantation of bone marrow (BM) HSCs from transgenic mice that express hGPIbα (hGPIbα(tg+/+) ), we sought to (i) determine the percentage of hGPIbα(tg+/+) HSCs required for therapeutic benefit, (ii) evaluate the efficacy of non-myeloablative conditioning using busulfan, and (iii) test the ability of anti-thymocyte globulin (ATG) to prevent/reduce undesirable immune responses. RESULTS: Transplantation of 10-20% hGPIbα(tg+/+) BM HSCs mixed with GPIbα(null) BM HSCs into irradiated GPIbα(null) mice was sufficient to correct bleeding time (n = 5). Transplantation of hGPIbα(tg+/+) BM HSCs into busulfan-conditioned GPIbα(null) mice corrected bleeding time in 21 of 27 recipients. Antibody response to hGPIbα and immune-mediated thrombocytopenia was documented in eight of 27 recipients, suggesting immunogenicity of hGPIbα in busulfan-conditioned GPIbα(null) mice. However, these antibodies disappeared without treatment within 30 weeks after transplantation. A combination of busulfan plus ATG conditioning successfully prevented antibody development and significantly increased therapeutic engraftment. CONCLUSION: A conditioning regimen of busulfan in combination with ATG could potentially be used in non-myeloablative autologous gene therapy in human BSS.
Assuntos
Síndrome de Bernard-Soulier/terapia , Bussulfano/administração & dosagem , Condicionamento Pré-Transplante , Animais , Síndrome de Bernard-Soulier/genética , Tempo de Sangramento , Modelos Animais de Doenças , Técnicas de Transferência de Genes , Terapia Genética , Transplante de Células-Tronco Hematopoéticas , Humanos , Sistema Imunitário , Imunossupressores/química , Lentivirus , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Fenótipo , Trombocitopenia/metabolismo , TransgenesRESUMO
BACKGROUND: von Willebrand factor (VWF) is a glycoprotein that plays an important role in primary hemostasis. VWF is synthesized and stored in endothelial cells (ECs) and megakaryocytes/platelets. Plasma VWF is primarily derived from ECs and is generally believed to be essential for hemostasis. VWF synthesized in megakaryocytes is stored in platelet α-granules, from which it is released following platelet activation. The relative contribution of VWF stored in ECs or megakaryocytes/platelets or present in plasma to hemostasis is not clear. OBJECTIVES: We investigated whether EC-derived VWF plays the major role in hemostasis while the contribution of platelet-derived VWF is negligible, or if platelet-derived VWF also significantly contributes to hemostasis. METHODS AND RESULTS: Mice expressing VWF only in ECs (EC-VWF) or platelets (Plt-VWF) were created by reciprocal bone marrow transplantation between C57BL/6J (WT) and VWF knockout mice (VWF-/-). Plasma VWF levels in EC-VWF were similar to WT. Plt-VWF mice had a trace amount of VWF in their plasma while VWF levels in platelet lysate were comparable to WT. Tail bleeding time was normal in EC-VWF. Interestingly, Plt-VWF showed partially corrected bleeding time and significantly decreased blood loss volume compared with VWF-/-. Adhesion of platelets perfused over immobilized collagen under shear stress was significantly higher in both EC-VWF and Plt-VWF compared with VWF-/-. CONCLUSION: VWF synthesized in ECs is sufficient to support hemostasis in VWF-/- mice, and VWF produced in megakaryocytes/platelets can also contribute to hemostasis in the absence of EC-derived VWF.
Assuntos
Plaquetas/metabolismo , Células Endoteliais/metabolismo , Hemostasia , Adesividade Plaquetária , Fator de von Willebrand/metabolismo , Animais , Tempo de Sangramento , Plaquetas/efeitos dos fármacos , Transplante de Medula Óssea , Colágeno/metabolismo , Células Endoteliais/efeitos dos fármacos , Epinefrina/administração & dosagem , Hemostasia/efeitos dos fármacos , Injeções Subcutâneas , Megacariócitos/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Adesividade Plaquetária/efeitos dos fármacos , Fatores de Tempo , Fator de von Willebrand/genéticaRESUMO
The inhibitory mechanism against proteases is important in the maintenance of homeostasis or health in the body. The human ovalbumin serpin (ov-serpin)/clade B serpin family is one group of the human serpins, a family of serine protease inhibitors. They have acquired diversity in the profiles of target proteases, inhibitory mechanisms, and localization patterns during their evolution. Most serpins target serine proteases, however, some ov-serpins target only cysteine proteases or both serine and cysteine proteases and furthermore, several ov-serpins do not possess inhibitory activities. Although the ov-serpins act primarily as intracellular serpins, some show extracellular and nuclear localizations. Such diversity enables the ov-serpins to play multiple physiological roles in the body. Recent analyses have revealed that the functions of human ov-serpins are more diversified than we previously knew. In this article, we describe recent progress in our understanding of how the human ov-serpin/clade B serpin family demonstrates diversity.
Assuntos
Ovalbumina/metabolismo , Serpinas/metabolismo , Animais , Evolução Molecular , Humanos , Ovalbumina/química , Ovalbumina/genética , Peptídeo Hidrolases/metabolismo , Serpinas/química , Serpinas/genéticaRESUMO
We herein report a case of hemophagocytic syndrome that developed in a 25-yr-old man with fulminant ulcerative colitis and presumed acute pancreatitis. Physical examination on admission showed a chronically ill, delirious patient with an upper abdominal mass. Peripheral blood showed progressive pancytopenia and bone marrow aspirate smears revealed hypocellular bone marrow with an increase of histiocytes showing prominent hemophagocytosis. Plain abdominal radiography revealed toxic megacolon. Both ultrasound and computed tomography showed the enlargement of the pancreas, thus indicating presumed acute pancreatitis. No apparent neoplasms or viral or bacterial infections, which are normally reported to be the cause of hemophagocytic syndrome, were detected. The patient was successfully treated with high doses of prednisolone and gamma-globulin.
Assuntos
Colite Ulcerativa/complicações , Histiocitose de Células não Langerhans/complicações , Pancreatite/complicações , Doença Aguda , Adulto , Anti-Inflamatórios/uso terapêutico , Anti-Inflamatórios não Esteroides/uso terapêutico , Colite Ulcerativa/terapia , Histiocitose de Células não Langerhans/terapia , Humanos , Imunização Passiva , Masculino , Prednisolona/uso terapêuticoRESUMO
Inherited, single-base substitutions are found at only two positions, C(-)52T and C(-)92G, within the proximal 5'-regulatory region (within -1096 to +48) of the human integrin alpha(2) gene. We recently reported that the T(-)52 substitution results in decreased binding of transcription factor Sp1 to adjacent binding sites, decreased transcription of the alpha(2) gene, and reduced densities of platelet alpha(2)beta(1). In this study, we identify an additional Sp1-binding site at position -107 to -99 and show that the adjacent dimorphic sequence C(-)92G also influences the rate of gene transcription. In the erythroleukemia cell line Dami, transfected promoter-luciferase constructs bearing the G(-)92 sequence exhibit roughly a 3-fold decrease in activity relative to the C(-)92 constructs. In transfected CHRF-288-11 megakaryocytic cells, the corresponding activity decreases by 5-fold. DNase I footprinting of the promoter region with Dami nuclear extracts showed a protected segment at -107 to -99 that can be deprotected by coincubation with molar excess of a consensus Sp1 oligonucleotide. Gel mobility shift assays and supershift assays with specific antibodies indicate that Sp1 binds to this region of the alpha(2) gene promoter. Mutation of the Sp1 binding element within -107 to -99 in constructs containing either C(-)92 or G(-)92 abolishes basal promoter activity and eliminates the binding of Sp1. The G(-)92 sequence has a gene frequency of 0.15 in a typical Caucasian population, and the presence of this allele correlates with reduced densities of platelet alpha(2)beta(1). The combined substitution G(-)92/T(-)52 has an additive influence on gene transcription, resulting in an 8-fold decrease in transfected Dami cells or a 20-fold decrease in transfected CHRF-288-11 cells. In summary, the natural dimorphism C(-)92G within the proximal 5'-regulatory region of the human integrin alpha(2) gene contributes to the regulation of integrin alpha(2)beta(1) expression on megakaryocytes and blood platelets and must thereby modulate collagen-related platelet function in vivo.