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1.
JAMA ; 319(1): 38-48, 2018 01 02.
Artigo em Inglês | MEDLINE | ID: mdl-29297078

RESUMO

Importance: Early exposure to complex dietary proteins may increase the risk of type 1 diabetes in children with genetic disease susceptibility. There are no intact proteins in extensively hydrolyzed formulas. Objective: To test the hypothesis that weaning to an extensively hydrolyzed formula decreases the cumulative incidence of type 1 diabetes in young children. Design, Setting, and Participants: An international double-blind randomized clinical trial of 2159 infants with human leukocyte antigen-conferred disease susceptibility and a first-degree relative with type 1 diabetes recruited from May 2002 to January 2007 in 78 study centers in 15 countries; 1081 were randomized to be weaned to the extensively hydrolyzed casein formula and 1078 to a conventional formula. The follow-up of the participants ended on February 28, 2017. Interventions: The participants received either a casein hydrolysate or a conventional adapted cow's milk formula supplemented with 20% of the casein hydrolysate. The minimum duration of study formula exposure was 60 days by 6 to 8 months of age. Main Outcomes and Measures: Primary outcome was type 1 diabetes diagnosed according to World Health Organization criteria. Secondary outcomes included age at diabetes diagnosis and safety (adverse events). Results: Among 2159 newborn infants (1021 female [47.3%]) who were randomized, 1744 (80.8%) completed the trial. The participants were observed for a median of 11.5 years (quartile [Q] 1-Q3, 10.2-12.8). The absolute risk of type 1 diabetes was 8.4% among those randomized to the casein hydrolysate (n = 91) vs 7.6% among those randomized to the conventional formula (n = 82) (difference, 0.8% [95% CI, -1.6% to 3.2%]). The hazard ratio for type 1 diabetes adjusted for human leukocyte antigen risk group, duration of breastfeeding, duration of study formula consumption, sex, and region while treating study center as a random effect was 1.1 (95% CI, 0.8 to 1.5; P = .46). The median age at diagnosis of type 1 diabetes was similar in the 2 groups (6.0 years [Q1-Q3, 3.1-8.9] vs 5.8 years [Q1-Q3, 2.6-9.1]; difference, 0.2 years [95% CI, -0.9 to 1.2]). Upper respiratory infections were the most common adverse event reported (frequency, 0.48 events/year in the hydrolysate group and 0.50 events/year in the control group). Conclusions and Relevance: Among infants at risk for type 1 diabetes, weaning to a hydrolyzed formula compared with a conventional formula did not reduce the cumulative incidence of type 1 diabetes after median follow-up for 11.5 years. These findings do not support a need to revise the dietary recommendations for infants at risk for type 1 diabetes. Trial Registration: clinicaltrials.gov Identifier: NCT00179777.


Assuntos
Caseínas , Diabetes Mellitus Tipo 1/prevenção & controle , Fórmulas Infantis , Criança , Diabetes Mellitus Tipo 1/epidemiologia , Intervalo Livre de Doença , Método Duplo-Cego , Feminino , Seguimentos , Humanos , Fenômenos Fisiológicos da Nutrição do Lactente , Recém-Nascido , Masculino , Política Nutricional , Risco
2.
JAMA ; 311(22): 2279-87, 2014 Jun 11.
Artigo em Inglês | MEDLINE | ID: mdl-24915259

RESUMO

IMPORTANCE: The disease process leading to clinical type 1 diabetes often starts during the first years of life. Early exposure to complex dietary proteins may increase the risk of ß-cell autoimmunity in children at genetic risk for type 1 diabetes. Extensively hydrolyzed formulas do not contain intact proteins. OBJECTIVE: To test the hypothesis that weaning to an extensively hydrolyzed formula decreases the cumulative incidence of diabetes-associated autoantibodies in young children. DESIGN, SETTING, AND PARTICIPANTS: A double-blind randomized clinical trial of 2159 infants with HLA-conferred disease susceptibility and a first-degree relative with type 1 diabetes recruited from May 2002 to January 2007 in 78 study centers in 15 countries; 1078 were randomized to be weaned to the extensively hydrolyzed casein formula and 1081 were randomized to be weaned to a conventional cows' milk-based formula. The participants were observed to April 16, 2013. INTERVENTIONS: The participants received either a casein hydrolysate or a conventional cows' milk formula supplemented with 20% of the casein hydrolysate. MAIN OUTCOMES: AND MEASURES: Primary outcome was positivity for at least 2 diabetes-associated autoantibodies out of 4 analyzed. Autoantibodies to insulin, glutamic acid decarboxylase, and the insulinoma-associated-2 (IA-2) molecule were analyzed using radiobinding assays and islet cell antibodies with immunofluorescence during a median observation period of 7.0 years (mean, 6.3 years). RESULTS: The absolute risk of positivity for 2 or more islet autoantibodies was 13.4% among those randomized to the casein hydrolysate formula (n = 139) vs 11.4% among those randomized to the conventional formula (n = 117). The unadjusted hazard ratio for positivity for 2 or more autoantibodies among those randomized to be weaned to the casein hydrolysate was 1.21 (95% CI, 0.94-1.54), compared with those randomized to the conventional formula, while the hazard ratio adjusted for HLA risk, duration of breastfeeding, vitamin D use, study formula duration and consumption, and region was 1.23 (95% CI, 0.96-1.58). There were no clinically significant differences in the rate of reported adverse events between the 2 groups. CONCLUSIONS AND RELEVANCE: Among infants at risk for type 1 diabetes, the use of a hydrolyzed formula, when compared with a conventional formula, did not reduce the incidence of diabetes-associated autoantibodies after 7 years. These findings do not support a benefit from hydrolyzed formula. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00179777.


Assuntos
Autoanticorpos/análise , Autoimunidade , Diabetes Mellitus Tipo 1/epidemiologia , Diabetes Mellitus Tipo 1/imunologia , Fórmulas Infantis , Animais , Aleitamento Materno , Caseínas , Criança , Diabetes Mellitus Tipo 1/genética , Diabetes Mellitus Tipo 1/fisiopatologia , Diabetes Mellitus Tipo 1/prevenção & controle , Proteínas Alimentares/imunologia , Método Duplo-Cego , Feminino , Seguimentos , Humanos , Hidrólise , Incidência , Recém-Nascido , Células Secretoras de Insulina , Masculino , Leite/imunologia , Risco , Desmame
3.
Clin Vaccine Immunol ; 21(2): 203-11, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24334687

RESUMO

Broad consensus assigns T lymphocytes fundamental roles in inflammatory, infectious, and autoimmune diseases. However, clinical investigations have lacked fully characterized and validated procedures, equivalent to those of widely practiced biochemical tests with established clinical roles, for measuring core T cell functions. The Trial to Reduce Insulin-dependent diabetes mellitus in the Genetically at Risk (TRIGR) type 1 diabetes prevention trial used consecutive measurements of T cell proliferative responses in prospectively collected fresh heparinized blood samples shipped by courier within North America. In this article, we report on the quality control implications of this simple and pragmatic shipping practice and the interpretation of positive- and negative-control analytes in our assay. We used polyclonal and postvaccination responses in 4,919 samples to analyze the development of T cell immunocompetence. We have found that the vast majority of the samples were viable up to 3 days from the blood draw, yet meaningful responses were found in a proportion of those with longer travel times. Furthermore, the shipping time of uncooled samples significantly decreased both the viabilities of the samples and the unstimulated cell counts in the viable samples. Also, subject age was significantly associated with the number of unstimulated cells and T cell proliferation to positive activators. Finally, we observed a pattern of statistically significant increases in T cell responses to tetanus toxin around the timing of infant vaccinations. This assay platform and shipping protocol satisfy the criteria for robust and reproducible long-term measurements of human T cell function, comparable to those of established blood biochemical tests. We present a stable technology for prospective disease-relevant T cell analysis in immunological diseases, vaccination medicine, and measurement of herd immunity.


Assuntos
Sangue/imunologia , Manejo de Espécimes/métodos , Linfócitos T/imunologia , Linfócitos T/fisiologia , Proliferação de Células , Sobrevivência Celular , Criança , Pré-Escolar , Estudos de Coortes , Feminino , Humanos , Lactente , Masculino , América do Norte , Estudos Prospectivos , Fatores de Tempo
4.
Pediatr Diabetes ; 13(5): 425-31, 2012 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-22251851

RESUMO

AIM: To evaluate the relationships between early growth and regional variations in type 1 diabetes (T1D) incidence in an international cohort of children with familial and genetic risk for T1D. METHODS: Anthropometric indices between birth to 5 yr of age were compared among regions and T1D proband in 2160 children participating in the Trial to Reduce Insulin-dependent diabetes mellitus in the Genetically at Risk study. RESULTS: Children in Northern Europe had the highest weight z-score between birth to 12 months of age, while those in Southern Europe and U.S.A. had the lowest weight and length/height z-scores at most time points (p < 0.005 to p < 0.001). Few differences in z-score values for weight, height, and body mass index were found by maternal T1D status. Using International Obesity Task Force criteria, the obesity rates generally increased with age and at 5 yr were highest in males in Northern Europe (6.0%) and in females in Canada (12.8%). However, no statistically significance difference was found by geographic region. In Canada, the obesity rate for female children of mothers with and without T1D differed significantly at 4 and 5 yr (6.0 vs. 0.0% and 21.3 vs. 1.9%, respectively; p < 0.0125) but no differences by maternal T1D status were found in other regions. CONCLUSIONS: There are regional differences in early childhood growth that are consistent with the higher incidence of T1D in Northern Europe and Canada as compared to Southern Europe. Our prospective study from birth will allow evaluation of relationships between growth and the emerging development of autoimmunity and progression to T1D by region in this at-risk population of children.


Assuntos
Diabetes Mellitus Tipo 1/fisiopatologia , Crescimento/fisiologia , Obesidade/epidemiologia , Estatura , Índice de Massa Corporal , Peso Corporal , Canadá/epidemiologia , Criança , Pré-Escolar , Diabetes Mellitus Tipo 1/epidemiologia , Europa (Continente)/epidemiologia , Feminino , Humanos , Lactente , Masculino , Obesidade/complicações , Estudos Prospectivos , Estados Unidos/epidemiologia , População Branca/estatística & dados numéricos
5.
J Clin Endocrinol Metab ; 96(9): 2826-34, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21697250

RESUMO

CONTEXT: The active metabolite of vitamin D, 1,25-dihydroxyvitamin D [1,25(OH)(2)D], is a potent modulator of immune cells in vitro. OBJECTIVE: Our objective was to determine whether the sun-dependent nutrient, cholecalciferol, can alter disease-associated cellular immune abnormalities in patients with multiple sclerosis (MS). DESIGN: This was an open-label, 12-month, randomized controlled trial. SETTING: Patients with MS were recruited from the MS Clinic at St. Michael's Hospital, Toronto. PATIENTS: Forty-nine patients were matched (for age, sex, disease duration, disease-modifying drug, and disability) and enrolled (treated n = 25; control n = 24). Four patients were lost to follow-up (n = 2 from each group). INTERVENTION: Treated patients received increasing doses of cholecalciferol (4,000-40,000 IU/d) plus calcium (1200 mg/d), followed by equilibration to a moderate, physiological intake (10,000 IU/d). Control patients did not receive supplements. MAIN OUTCOME MEASURES: At enrollment and at 12 months, peripheral blood mononuclear cell (PBMC) proliferative responses to disease-associated, MS-relevant, and control antigens were measured, along with selected serum biochemical markers. RESULTS: At 12 months, mean serum 25-hydroxyvitamin D [25(OH)D] concentrations were 83 ± 35 nmol/liter and 179 ± 76 nmol/liter in control and treated participants, respectively (paired t, P < 0.001). Serum 1,25(OH)(2)D did not differ between baseline and 1 yr. In treated patients, 12-month PBMC proliferative responses to neuron antigens myelin basic protein and exon-2 were suppressed (P = 0.002). In controls, there were no significant changes in disease-associated PBMC responsiveness. There were no significant differences between groups in levels of selected biomarkers. INTERPRETATION: MS-associated, abnormal T cell reactivities were suppressed in vivo by cholecalciferol at serum 25(OH)D concentrations higher than 100 nmol/liter.


Assuntos
Cálcio/uso terapêutico , Colecalciferol/uso terapêutico , Leucócitos Mononucleares/efeitos dos fármacos , Esclerose Múltipla/tratamento farmacológico , Vitaminas/uso terapêutico , Adulto , Cálcio/administração & dosagem , Cálcio/sangue , Colecalciferol/administração & dosagem , Citocinas/sangue , Esquema de Medicação , Feminino , Humanos , Leucócitos Mononucleares/imunologia , Perda de Seguimento , Masculino , Esclerose Múltipla/sangue , Esclerose Múltipla/imunologia , Resultado do Tratamento , Vitamina D/sangue , Vitaminas/administração & dosagem
6.
N Engl J Med ; 363(20): 1900-8, 2010 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-21067382

RESUMO

BACKGROUND: Early exposure to complex dietary proteins may increase the risk of beta-cell autoimmunity and type 1 diabetes in children with genetic susceptibility. We tested the hypothesis that supplementing breast milk with highly hydrolyzed milk formula would decrease the cumulative incidence of diabetes-associated autoantibodies in such children. METHODS: In this double-blind, randomized trial, we assigned 230 infants with HLA-conferred susceptibility to type 1 diabetes and at least one family member with type 1 diabetes to receive either a casein hydrolysate formula or a conventional, cow's-milk-based formula (control) whenever breast milk was not available during the first 6 to 8 months of life. Autoantibodies to insulin, glutamic acid decarboxylase (GAD), the insulinoma-associated 2 molecule (IA-2), and zinc transporter 8 were analyzed with the use of radiobinding assays, and islet-cell antibodies were analyzed with the use of immunofluorescence, during a median observation period of 10 years (mean, 7.5). The children were monitored for incident type 1 diabetes until they were 10 years of age. RESULTS: The unadjusted hazard ratio for positivity for one or more autoantibodies in the casein hydrolysate group, as compared with the control group, was 0.54 (95% confidence interval [CI], 0.29 to 0.95), and the hazard ratio adjusted for an observed difference in the duration of exposure to the study formula was 0.51 (95% CI, 0.28 to 0.91). The unadjusted hazard ratio for positivity for two or more autoantibodies was 0.52 (95% CI, 0.21 to 1.17), and the adjusted hazard ratio was 0.47 (95% CI, 0.19 to 1.07). The rate of reported adverse events was similar in the two groups. CONCLUSIONS: Dietary intervention during infancy appears to have a long-lasting effect on markers of beta-cell autoimmunity--markers that may reflect an autoimmune process leading to type 1 diabetes. (ClinicalTrials.gov number, NCT00570102.).


Assuntos
Autoanticorpos/sangue , Autoimunidade , Diabetes Mellitus Tipo 1/prevenção & controle , Predisposição Genética para Doença , Fórmulas Infantis , Células Secretoras de Insulina/imunologia , Animais , Biomarcadores/sangue , Caseínas/efeitos adversos , Caseínas/imunologia , Caseínas/uso terapêutico , Criança , Diabetes Mellitus Tipo 1/genética , Progressão da Doença , Método Duplo-Cego , Teste de Histocompatibilidade , Humanos , Lactente , Recém-Nascido , Leite/imunologia , Leite Humano , Projetos Piloto
7.
Diabetes ; 57(4): 918-28, 2008 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-18198358

RESUMO

OBJECTIVE: Type 1 diabetes reflects autoimmune destruction of beta-cells and peri-islet Schwann cells (pSCs), but the mechanisms of pSC death and the T-cell epitopes involved remain unclear. RESEARCH DESIGN AND METHODS: Primary pSC cultures were generated and used as targets in cytotoxic T-lymphocyte (CTL) assays in NOD mice. Cognate interaction between pSC and CD8(+) T-cells was assessed by transgenic restoration of beta2-microglobulin (beta2m) to pSC in NOD.beta2m(-/-) congenics. I-A(g7) and K(d) epitopes in the pSC antigen glial fibrillary acidic protein (GFAP) were identified by peptide mapping or algorithms, respectively, and the latter tested by immunotherapy. RESULTS: pSC cultures did not express major histocompatibility complex (MHC) class II and were lysed by ex vivo CTLs from diabetic NOD mice. In vivo, restoration of MHC class I in GFAP-beta2m transgenics significantly accelerated adoptively transferred diabetes. Target epitopes in the pSC autoantigen GFAP were mapped to residues 79-87 and 253-261 for K(d) and 96-110, 116-130, and 216-230 for I-A(g7). These peptides were recognized spontaneously in NOD spleens as early as 2.5 weeks of age, with proliferative responses peaking around weaning and detectable lifelong. Several were also recognized by T-cells from new-onset type 1 diabetic patients. NOD mouse immunotherapy at 8 weeks with the CD8(+) T-cell epitope, GFAP 79-87 but not 253-261, significantly inhibited type 1 diabetes and was associated with reduced gamma-interferon production to whole protein GFAP. CONCLUSIONS: Collectively, these findings elucidate a role for pSC-specific CD8(+) T-cells in islet inflammation and type 1 diabetes pathogenesis, further supporting neuronal involvement in beta-cell demise.


Assuntos
Diabetes Mellitus Tipo 1/imunologia , Animais , Diabetes Mellitus Tipo 1/patologia , Feminino , Proteína Glial Fibrilar Ácida/genética , Insulina/genética , Células Secretoras de Insulina/imunologia , Células Secretoras de Insulina/patologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos NOD , Camundongos Transgênicos , Ovulação , Células de Schwann/patologia , Linfócitos T Citotóxicos/imunologia , Microglobulina beta-2/deficiência , Microglobulina beta-2/genética
8.
Ann Neurol ; 63(1): 98-111, 2008 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-17932975

RESUMO

OBJECTIVES: Pediatric-onset multiple sclerosis offers a unique window into early targets and mechanisms of immune dysregulation. It is unknown whether heightened T-cell reactivities documented in adult patients, to both target-organ and environmental antigens, emerge in parallel or develop as early or late events. Our objectives were to determine the presence, pattern, and specificity of abnormal T-cell reactivities to such antigens in the earliest stages of the multiple sclerosis process. METHODS: Peripheral T-cell proliferative responses to self-, dietary, and control antigens were blindly evaluated in a large cohort of well-characterized children (n = 172) with central nervous system (CNS) inflammatory demyelination (n = 63), recent-onset type 1 (insulin-dependent) diabetes mellitus (T1D; n = 41), nonautoimmune neurological conditions (n = 39), and healthy children (n = 29). RESULTS: Children with inflammatory demyelination, CNS injury, and T1D exhibited heightened T-cell reactivities to self-antigens, and these responses were not strictly limited to the disease target organs. Children with autoimmune disease and CNS injury also exhibited abnormal T-cell responses against multiple cow-milk proteins. Responses to specific milk epitopes distinguished T1D from inflammatory demyelination and other neurological diseases. INTERPRETATION: Abnormal T-cell reactivities to self- and environmental antigens manifest in the earliest clinical stages of inflammatory demyelination and T1D. The pattern of heightened T-cell reactivities implicates both shared and distinct mechanisms of immune dysregulation in the different autoimmune diseases. Abnormal T-cell responses in children with tissue injury challenge the prevailing view that CNS autoreactive cells inherently mediate the disease in early multiple sclerosis.


Assuntos
Autoantígenos/imunologia , Autoimunidade/imunologia , Diabetes Mellitus Tipo 1/imunologia , Ativação Linfocitária/imunologia , Esclerose Múltipla/imunologia , Linfócitos T/imunologia , Adolescente , Adulto , Fatores Etários , Sistema Nervoso Central/imunologia , Sistema Nervoso Central/fisiopatologia , Criança , Pré-Escolar , Estudos de Coortes , Diabetes Mellitus Tipo 1/fisiopatologia , Proteínas Alimentares/imunologia , Feminino , Substâncias Perigosas/imunologia , Humanos , Sistema Imunitário/imunologia , Sistema Imunitário/fisiopatologia , Doenças do Sistema Imunitário/imunologia , Doenças do Sistema Imunitário/fisiopatologia , Lactente , Masculino , Esclerose Múltipla/fisiopatologia , Tolerância a Antígenos Próprios/imunologia
9.
Ann N Y Acad Sci ; 1150: 32-42, 2008 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-19120264

RESUMO

Type 1 diabetes (T1D) is caused by autoimmune beta cell destruction. The early events triggering T1D and the forces that keep diabetic autoimmunity pancreas specific have been unclear. Our discovery that autoimmune islet destruction is not beta-cell-exclusive but includes cytotoxic T cell targeting of peri-islet glia, evoked the possibility that T1D pathogenesis may involve neuronal elements beyond beta cell/immune interactions. Recently, we have found that sensory afferent neurons are a critical component in prediabetes initiation, promoting islet inflammation through altered glucose homeostasis and progressive beta cell stress. These factors orchestrate a catastrophic cascade culminating in insulin insufficiency mediated by an autoimmune-prone host. This neuro-immuno-endocrinological triad explains diabetic inflammation as a consequence of local neuropeptide deficiency, leading to an innovative concept of disease pathogenesis with novel therapeutic implications.


Assuntos
Diabetes Mellitus Tipo 1/etiologia , Células Secretoras de Insulina/fisiologia , Ilhotas Pancreáticas/inervação , Neuroglia/fisiologia , Neuroimunomodulação/fisiologia , Neurônios/fisiologia , Animais , Diabetes Mellitus Tipo 1/genética , Diabetes Mellitus Tipo 1/patologia , Modelos Animais de Doenças , Humanos , Ilhotas Pancreáticas/citologia , Camundongos , Camundongos Endogâmicos NOD , Modelos Biológicos , Neuroimunomodulação/genética , Pâncreas/inervação , Pâncreas/patologia
10.
J Clin Immunol ; 27(4): 388-96, 2007 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-17436063

RESUMO

INTRODUCTION: Although myelin autoimmunity is known to be a major factor in the pathogenesis of multiple sclerosis (MS), the role of nonmyelin antigens is less clear. Given the complexity of this disease, it is possible that autoimmunity against nonmyelin antigens also has a pathogenic role. Autoantibodies against enolase and arrestin have previously been reported in MS patients. The T-cell response to these antigens, however, has not been established. METHODS: Thirty-five patients with MS were recruited, along with thirty-five healthy controls. T-cell proliferative responses against non-neuronal enolase, neuron-specific enolase (NSE), retinal arrestin, beta-arrestin, and myelin basic protein were determined. RESULTS: MS patients had a greater prevalence of positive T-cell proliferative responses to NSE, retinal arrestin, and beta-arrestin than healthy controls (p<0.0001). The proliferative response against NSE, retinal arrestin, and beta-arrestin correlated with the response against myelin basic protein (p < or = 0.004). Furthermore, the proliferative response against retinal arrestin was correlated to beta-arrestin (p<0.0001), whereas there was no such correlation between non-neuronal enolase and NSE (p = 0.23). DISCUSSION: There is accumulating evidence to suggest that the pathogenesis of MS involves more than just myelin autoimmunity/destruction. Autoimmunity against nonmyelin antigens may be a component of this myriad of immunopathological events. NSE, retinal arrestin, and beta-arrestin are novel nonmyelin autoantigens that deserve further investigation in this respect. Autoimmunity against these antigens may be linked to neurodegeneration, defective remyelination, and predisposition to uveitis in multiple sclerosis. Further investigation of the role of these antigens in MS is warranted.


Assuntos
Arrestina/imunologia , Autoantígenos/imunologia , Esclerose Múltipla/imunologia , Fosfopiruvato Hidratase/imunologia , Adulto , Sequência de Aminoácidos , Arrestina/farmacologia , Autoantígenos/farmacologia , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , Relação Dose-Resposta Imunológica , Feminino , Humanos , Epitopos Imunodominantes , Ativação Linfocitária/efeitos dos fármacos , Masculino , Dados de Sequência Molecular , Fosfopiruvato Hidratase/farmacologia , Valores de Referência , Alinhamento de Sequência , Linfócitos T/efeitos dos fármacos , Linfócitos T/imunologia
11.
J Neurosci ; 26(44): 11387-96, 2006 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-17079667

RESUMO

Modification of arginine residues by citrullination is catalyzed by peptidylarginine deiminases (PADs), of which five are known, generating irreversible protein structural modifications. We have shown previously that enhanced citrullination of myelin basic protein contributed to destabilization of the myelin membrane in the CNS of multiple sclerosis (MS) patients. We now report increased citrullination of nucleosomal histones by PAD4 in normal-appearing white matter (NAWM) of MS patients and in animal models of demyelination. Histone citrullination was attributable to increased levels and activity of nuclear PAD4. PAD4 translocation into the nucleus was attributable to elevated tumor necrosis factor-alpha (TNF-alpha) protein. The elevated TNF-alpha in MS NAWM was not associated with CD3+ or CD8+ lymphocytes, nor was it associated with CD68+ microglia/macrophages. GFAP, a measure of astrocytosis, was the only cytological marker that was consistently elevated in the MS NAWM, suggesting that TNF-alpha may have been derived from astrocytes. In cell cultures of mouse and human oligodendroglial cell lines, PAD4 was predominantly cytosolic but TNF-alpha treatment induced its nuclear translocation. To address the involvement of TNF-alpha in targeting PAD4 to the nucleus, we found that transgenic mice overexpressing TNF-alpha also had increased levels of citrullinated histones and elevated nuclear PAD4 before demyelination. In conclusion, high citrullination of histones consequent to PAD4 nuclear translocation is part of the process that leads to irreversible changes in oligodendrocytes and may contribute to apoptosis of oligodendrocytes in MS.


Assuntos
Encéfalo/metabolismo , Citrulina/metabolismo , Modelos Animais de Doenças , Histonas/metabolismo , Hidrolases/metabolismo , Esclerose Múltipla/metabolismo , Fator de Necrose Tumoral alfa/fisiologia , Transporte Ativo do Núcleo Celular/fisiologia , Animais , Encéfalo/patologia , Doenças Desmielinizantes/genética , Doenças Desmielinizantes/metabolismo , Doenças Desmielinizantes/patologia , Feminino , Histonas/genética , Humanos , Hidrolases/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Esclerose Múltipla/genética , Esclerose Múltipla/patologia , Proteína-Arginina Desiminase do Tipo 4 , Desiminases de Arginina em Proteínas
12.
Burns ; 32(6): 748-54, 2006 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-16920268

RESUMO

We assessed the in vitro bactericidal efficacy of a new sunburn gel (Rescudermtrade mark; RESC) against planktonic and sessile Pseudomonas aeruginosa (PSEUD) and Staphylococcus epidermidis (STAPH). While PSEUD levels were 4log(10) lower than those of STAPH within 24h of adding RESC to contaminated nutrient broths, all bacterial counts were comparable by 48h. PSEUD and STAPH levels were then measured after applying either a single or three consecutive aliquots of RESC to polyurethane sponges. Gel was removed after 5 or 20min, or left on for 72h. Bacterial counts in placebo-treated sponges had plateaued by 24h to values above 9log(10)CFU/mL. In contrast, six out of seven of the RESC application modalities reduced bacterial levels below 4log(10)CFU/mL for 72h. RESC remained effective against STAPH despite up to a 24h treatment delay, irrespective of the number of applications. Repeated RESC applications were required to maintain PSEUD below 4log(10)CFU/mL when the delay exceeded 7h. These data demonstrate the differential susceptibility of planktonic and sessile bacteria to RescuDermtrade mark. This product might be a good candidate for reducing the opportunity for wound infection, especially in burns.


Assuntos
Anti-Infecciosos Locais/uso terapêutico , Pseudomonas aeruginosa/efeitos dos fármacos , Staphylococcus epidermidis/efeitos dos fármacos , Protetores Solares/uso terapêutico , Queimaduras/microbiologia , Géis , Humanos , Técnicas In Vitro , Testes de Sensibilidade Microbiana , Infecções por Pseudomonas/tratamento farmacológico , Infecções Cutâneas Estafilocócicas/tratamento farmacológico , Infecção dos Ferimentos/microbiologia
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