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1.
Front Nutr ; 8: 756413, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34778345

RESUMO

Background: The world is still struggling to control the COVID-19 pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The level of uncertainty regarding the virus is still significantly high. The virus behaves differently in children and young adults. Most children and adolescents are either asymptomatic or have mild symptoms. They generally have a very good prognosis. However, it is not well-known whether children and young adults with type 2 diabetes are at risk of getting a severe infection of COVID-19. Many Muslim children with type 2 diabetes have been performing dawn to dusk fasting during the month of Ramadan, before and during the COVID-19 pandemic, and the impact of this on their health has not been well investigated. Previous studies in adults have suggested that intermittent fasting may be beneficial in different ways including reversal of type 2 diabetes and prevention of COVID-19 infection. Objective: The primary aim of this narrative review is to summarise the impacts of the COVID-19 pandemic on children and young adults with type 2 diabetes, and to identify the knowledge gaps in the literature. It also explores the potential of intermittent fasting in reversing the pathogenesis of diabetes and highlighting how this approach could prevent these patients from developing chronic complications. Methods: This narrative review has been produced by examining several databases, including Google Scholar, Research Gate, PubMed, Cochrane Library, MEDLINE (EBSCO), and Web of Science. The most common search terms used were "COVID-19 AND Children", "SARS-CoV-2 AND/OR Children", "COVID-19 AND Diabetes" "COVID-19 Epidemiology", "COVID-19 AND Ramadan fasting", "COVID-19 and Intermittent fasting." All the resources used are either peer-reviewed articles/reports and/or official websites of various media, governmental and educational organisations. Results: Having reviewed the currently limited evidence, it has been found that the incidence of COVID-19 among children with type 2 diabetes seems to be not much different from children without diabetes. However, these patients are still vulnerable to any infection. Several studies have reported that prevention programmes such as intermittent fasting are effective to protect these groups of patients from developing any complications. Moreover, observing Ramadan fasting as a type of intermittent fasting could be beneficial for some children with established diabetes, prediabetes and people at risk. Conclusion: Children and young adults with type 2 diabetes are not at risk of severe COVID-19 infection as the case in adults with diabetes. More research is needed to identify the impact of COVID-19 and to investigate the efficacy and safety of intermittent fasting, including Ramadan fasting, among these age groups. Implementing these cost-effective programmes may have a great impact in minimising the incidence of diabetes. Moreover, this could be effective particularly at prediabetes stage by preventing these people from going onto develop type 2 diabetes and taking medications for the rest of their life and protecting people from complications linked to disease and infection.

2.
Eur J Endocrinol ; 183(6): 581-595, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33055295

RESUMO

OBJECTIVE: Copy number variation (CNV) has been associated with idiopathic short stature, small for gestational age and Silver-Russell syndrome (SRS). It has not been extensively investigated in growth hormone insensitivity (GHI; short stature, IGF-1 deficiency and normal/high GH) or previously in IGF-1 insensitivity (short stature, high/normal GH and IGF-1). DESIGN AND METHODS: Array comparative genomic hybridisation was performed with ~60 000 probe oligonucleotide array in GHI (n = 53) and IGF-1 insensitivity (n = 10) subjects. Published literature, mouse models, DECIPHER CNV tracks, growth associated GWAS loci and pathway enrichment analyses were used to identify key biological pathways/novel candidate growth genes within the CNV regions. RESULTS: Both cohorts were enriched for class 3-5 CNVs (7/53 (13%) GHI and 3/10 (30%) IGF-1 insensitivity patients). Interestingly, 6/10 (60%) CNV subjects had diagnostic/associated clinical features of SRS. 5/10 subjects (50%) had CNVs previously reported in suspected SRS: 1q21 (n = 2), 12q14 (n = 1) deletions and Xp22 (n = 1), Xq26 (n = 1) duplications. A novel 15q11 deletion, previously associated with growth failure but not SRS/GHI was identified. Bioinformatic analysis identified 45 novel candidate growth genes, 15 being associated with growth in GWAS. The WNT canonical pathway was enriched in the GHI cohort and CLOCK was identified as an upstream regulator in the IGF-1 insensitivity cohorts. CONCLUSIONS: Our cohort was enriched for low frequency CNVs. Our study emphasises the importance of CNV testing in GHI and IGF-1 insensitivity patients, particularly GHI subjects with SRS features. Functional experimental evidence is now required to validate the novel candidate growth genes, interactions and biological pathways identified.


Assuntos
Variações do Número de Cópias de DNA/genética , Testes Genéticos/métodos , Hormônio do Crescimento Humano/genética , Fator de Crescimento Insulin-Like I/genética , Adolescente , Criança , Pré-Escolar , Estudos de Coortes , Feminino , Hormônio do Crescimento Humano/sangue , Humanos , Lactente , Fator de Crescimento Insulin-Like I/metabolismo , Masculino
3.
Hum Mol Genet ; 29(14): 2435-2450, 2020 08 11.
Artigo em Inglês | MEDLINE | ID: mdl-32620954

RESUMO

Dysfunction of the gonadotropin-releasing hormone (GnRH) axis causes a range of reproductive phenotypes resulting from defects in the specification, migration and/or function of GnRH neurons. To identify additional molecular components of this system, we initiated a systematic genetic interrogation of families with isolated GnRH deficiency (IGD). Here, we report 13 families (12 autosomal dominant and one autosomal recessive) with an anosmic form of IGD (Kallmann syndrome) with loss-of-function mutations in TCF12, a locus also known to cause syndromic and non-syndromic craniosynostosis. We show that loss of tcf12 in zebrafish larvae perturbs GnRH neuronal patterning with concomitant attenuation of the orthologous expression of tcf3a/b, encoding a binding partner of TCF12, and stub1, a gene that is both mutated in other syndromic forms of IGD and maps to a TCF12 affinity network. Finally, we report that restored STUB1 mRNA rescues loss of tcf12 in vivo. Our data extend the mutational landscape of IGD, highlight the genetic links between craniofacial patterning and GnRH dysfunction and begin to assemble the functional network that regulates the development of the GnRH axis.


Assuntos
Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Hormônio Liberador de Gonadotropina/genética , Síndrome de Kallmann/genética , Ubiquitina-Proteína Ligases/genética , Proteínas de Peixe-Zebra/genética , Adulto , Idoso , Animais , Modelos Animais de Doenças , Feminino , Genes Dominantes/genética , Hormônio Liberador de Gonadotropina/deficiência , Haploinsuficiência/genética , Humanos , Síndrome de Kallmann/patologia , Masculino , Pessoa de Meia-Idade , Mutação/genética , Neurônios/metabolismo , Neurônios/patologia , Fenótipo , Peixe-Zebra/genética
4.
BMC Public Health ; 19(1): 371, 2019 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-30943939

RESUMO

BACKGROUND: Physical activity and self-monitoring are important for children with type 1 diabetes mellitus (T1DM) but it is unclear whether interventions delivered online are feasible, acceptable to patients and efficacious. The aim was to assess the feasibility and acceptability of an internet-based physical activity and self-monitoring programme for children with T1DM, and of a randomised controlled trial (RCT) to evaluate efficacy. METHODS: A total of 49 children aged 9-12 with T1DM were randomly assigned to usual care only or to an interactive intervention group combining a website (STAK-D) and a PolarActive activity watch (PAW; Polar Electro (UK) Ltd.), alongside usual care. Participants completed self-report measures on their health, self-efficacy and physical activity at baseline (T0), eight weeks (T1) and six months (T2). They also wore a PAW to measure physical activity for one week at the end of T0, T1 and T2. Intervention participants were interviewed about their experiences at T2. Explanatory variables were examined using multi-level modelling and examination of change scores, 95% confidence intervals and p-values with alpha set at 0.95. Descriptive analysis was undertaken of the 'end-of-study questionnaire'. Qualitative analysis followed a framework approach. RESULTS: Completion rates for all self-report items and objective physical activity data were above 85% for the majority of measures. HbA1c data was obtained for 100% of participants, although complete clinical data was available for 63.3% to 63.5% of participants at each data collection time-point. Recruitment and data collection processes were reported to be acceptable to participants and healthcare professionals. Self-reported sedentary behaviour (-2.28, p=0.04, 95% CI=-4.40, -0.16; p = 0.04; dppc2 = 0.72) and parent-reported physical health of the child (6.15, p=0.01, 95%CI=1.75, 10.55; p = 0.01; dppc2 = 0.75) improved at eight weeks in the intervention group. CONCLUSIONS: The trial design was feasible and acceptable to participants and healthcare providers. Intervention engagement was low and technical challenges were evident in both online and activity watch elements, although enjoyment was high among users. Reported outcome improvements were observed at 8 weeks but were not sustained. TRIAL REGISTRATION: ISRCTN 48994721 (prospectively registered). Date of registration: 28.09.2016.


Assuntos
Diabetes Mellitus Tipo 1 , Exercício Físico , Internet , Satisfação do Paciente , Avaliação de Programas e Projetos de Saúde , Atitude do Pessoal de Saúde , Criança , Diabetes Mellitus Tipo 1/terapia , Estudos de Viabilidade , Feminino , Pessoal de Saúde , Nível de Saúde , Humanos , Masculino , Monitorização Ambulatorial , Comportamento Sedentário , Autoeficácia , Inquéritos e Questionários
5.
J Pediatr Endocrinol Metab ; 32(2): 151-157, 2019 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-30685744

RESUMO

Background The objective of the study was to evaluate the long-term outcome of paediatric-onset hyperthyroidism with follow-up into adulthood and to identify any early predictors of a need for definitive therapy (DT). Methods In a retrospective analysis of patients diagnosed with hyperthyroidism under the age of 18 years and at follow-up, a comparison was made by categorising them into those who underwent definitive therapy (DT group), i.e. thyroidectomy/radioactive iodine (RAI), those who remained on antithyroid drugs (ATD) (CBZ group) and those who had complete remission (RE group). Results Sixty-one (49 females, 12 males) patients with a median age of 15.1 years (range: 3.6-18) at diagnosis were studied. The duration of the first course of ATD varied from <1 year (7%), 1-2 years (26%), >2 years (46%) and ATD never discontinued (21%). Disease relapsed in 69% of patients with <1 year of ATD vs. 79% with >2 years of ATD. At follow-up, the median duration since diagnosis was 8.75 years (range 2.0-20.7 years) and the median age at follow-up was 23.2 years (8-36 years). Thirty-three percent (20/61) had undergone DT (DT group) - with 16.5% (n=10) on RAI and 16.5% (n=10) on surgery, 36% (22/61) were on ATD (CBZ group), whilst 32% (19/61) had undergone full remission (RE group). The comparison did not identify any statistically significant difference for predictor factors at diagnosis including age, T4 and free T4 levels, thyroid peroxidise antibody levels (TPO) and the duration of the first course of carbimazole (CBZ) treatment. Conclusion Long-term complete remission of paediatric-onset hyperthyroidism in our study was 31%. There were no predictors identified that could help predict the long-term outcome, especially into adulthood.


Assuntos
Antitireóideos/uso terapêutico , Hipertireoidismo/terapia , Radioisótopos do Iodo/uso terapêutico , Tireoidectomia/métodos , Adolescente , Criança , Feminino , Seguimentos , Humanos , Hipertireoidismo/patologia , Masculino , Indução de Remissão , Estudos Retrospectivos , Testes de Função Tireóidea , Resultado do Tratamento
6.
Artigo em Inglês | MEDLINE | ID: mdl-28620499

RESUMO

In the absence of maternal thyroid disease or iodine deficiency, fetal goitre is rare and usually attributable to dyshormonogenesis, for which genetic ascertainment is not always undertaken in the UK. Mechanical complications include tracheal and oesophageal compression with resultant polyhydramnios, malpresentation at delivery and neonatal respiratory distress. We report an Indian kindred in which the proband (first-born son) had congenital hypothyroidism (CH) without obvious neonatal goitre. His mother's second pregnancy was complicated by fetal hypothyroid goitre and polyhydramnios, prompting amniotic fluid drainage and intraamniotic therapy (with liothyronine, T3 and levothyroxine, T4). Sadly, intrauterine death occurred at 31 weeks. Genetic studies in the proband demonstrated compound heterozygous novel (c.5178delT, p.A1727Hfs*26) and previously described (c.7123G > A, p.G2375R) thyroglobulin (TG) mutations which are the likely cause of fetal goitre in the deceased sibling. TG mutations rarely cause fetal goitre, and management remains controversial due to the potential complications of intrauterine therapy however an amelioration in goitre size may be achieved with intraamniotic T4, and intraamniotic T3/T4 combination has achieved a favourable outcome in one case. A conservative approach, with surveillance, elective delivery and commencement of levothyroxine neonatally may also be justified, although intubation may be required post delivery for respiratory obstruction. Our observations highlight the lethality which may be associated with fetal goitre. Additionally, although this complication may recur in successive pregnancies, our case highlights the possibility of discordance for fetal goitre in siblings harbouring the same dyshormonogenesis-associated genetic mutations. Genetic ascertainment may facilitate prenatal diagnosis and assist management in familial cases. LEARNING POINTS: CH due to biallelic, loss-of-function TG mutations is well-described and readily treatable in childhood however mechanical complications from associated fetal goitre may include polyhydramnios, neonatal respiratory compromise and neck hyperextension with dystocia complicating delivery.CH due to TG mutations may manifest with variable phenotypes, even within the same kindred.Treatment options for hypothyroid dyshormogenic fetal goitre in a euthyroid mother include intraamniotic thyroid hormone replacement in cases with polyhydramnios or significant tracheal obstruction. Alternatively, cases may be managed conservatively with radiological surveillance, elective delivery and neonatal levothyroxine treatment, although intubation and ventilation may be required to support neonatal respiratory compromise.Genetic ascertainment in such kindreds may enable prenatal diagnosis and anticipatory planning for antenatal management of further affected offspring.

7.
Trials ; 17(1): 583, 2016 12 08.
Artigo em Inglês | MEDLINE | ID: mdl-27931254

RESUMO

BACKGROUND: Regular physical activity has important health benefits for children with type 1 diabetes mellitus (T1DM), yet children and their parents face barriers to participation such as lack of self-efficacy or concerns around hypoglycaemia. Multimedia interventions are useful for educating children about their health and demonstrate potential to improve children's health-related self-efficacy, but few paediatric clinics offer web-based resources as part of routine care. The Steps to Active Kids with Diabetes (STAK-D) programme is an online intervention grounded in psychological theory (social cognitive theory) and informed by extensive preliminary research. The aim of the programme is to encourage and support safe engagement with physical activity for children with T1DM. The aim of this research is to explore the feasibility of delivering the STAK-D programme to children aged 9-12 years with T1DM, and to assess the feasibility of further research to demonstrate its clinical and cost-effectiveness. METHODS: Up to 50 children aged 9-12 years with T1DM and their parents will be recruited from two paediatric diabetes clinics in the UK. Child-parent dyads randomised to the intervention group will have access to the intervention website (STAK-D) and a wrist-worn activity monitor for 6 months. The feasibility of intervention and further research will be assessed by rate of recruitment, adherence, retention, data completion and adverse events. Qualitative interviews will be undertaken with a subsample of children and parents (up to 25 dyads) and health care professionals (up to 10). Health outcomes and the feasibility of outcome measurement tools will be assessed. These include self-efficacy (CSAPPA), objective physical activity, self-reported physical activity (PAQ), fear of hypoglycaemia (CHFS; PHFS), glycaemic control (HbA1c), insulin dose, Body Mass Index (BMI), health-related quality of life (CHU9D; CHQ-PF28), health service use and patient-clinician communication. Assessments will be taken at baseline (T0), 8 weeks (T1) and at 6-month follow-up (T2). DISCUSSION: The goal of this feasibility trial is to assess the delivery of STAK-D to promote physical activity among children with T1DM, and to assess the potential for further, definitive research to demonstrate its effectiveness. Results will provide the information necessary to design a larger randomised controlled trial and maximise the recruitment rate, intervention delivery and trial retention. TRIAL REGISTRATION: ISRCTN, ISRCTN48994721 . Registered on 28 October 2016.


Assuntos
Diabetes Mellitus Tipo 1/terapia , Exercício Físico , Promoção da Saúde/métodos , Estilo de Vida Saudável , Internet , Actigrafia/instrumentação , Fatores Etários , Criança , Comportamento Infantil , Protocolos Clínicos , Diabetes Mellitus Tipo 1/diagnóstico , Diabetes Mellitus Tipo 1/fisiopatologia , Diabetes Mellitus Tipo 1/psicologia , Estudos de Viabilidade , Feminino , Monitores de Aptidão Física , Comportamentos Relacionados com a Saúde , Conhecimentos, Atitudes e Prática em Saúde , Nível de Saúde , Humanos , Masculino , Cooperação do Paciente , Projetos de Pesquisa , Autoeficácia , Fatores de Tempo , Resultado do Tratamento , Reino Unido
8.
Horm Res Paediatr ; 2015 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-25924833

RESUMO

BACKGROUND: The insulin-like growth factor 1 receptor (IGF IR) gene is located on chromosome 15q26.3. Heterozygous 15q26 deletions involving the IGFIR gene are rare, resulting in intrauterine and postnatal growth retardation, developmental delay and microcephaly. Limited evidence exists on the effect of growth hormone (GH) therapy in these cases. METHODS: We report a series of cases with 15q26 deletions, including response to GH treatment. RESULTS: Seven children (2 males) presented with short stature [median height standard deviation score (SDS) of -4.8 (range -3.0 to -5.6)]. GH was started at a median age of 5 years (range 1.8 to 12.4) for a median duration of 5.8 years (range 1.0 to 12.4). Median height SDS increased by +0.6 (range 0.1 to 1.0), +1.3 (range 0.1 to 2.4) and +1.4 (range 0.8 to 3.3) after 1 (n = 7), 5 (n = 4) and 10 years (n = 3) of GH treatment, respectively. Four patients reached final height after 5.8 to 12.4 years of GH with a median change in height SDS of +1.1 (range 0 to 3.3). CONCLUSION: This study demonstrates a moderate, though variable, response to GH therapy, suggesting that GH resistance caused by heterozygous IGFIR deletions can be partially overcome by GH therapy. The first-year response was moderate, and whilst long-term treatment improved height SDS, the final adult height remained reduced. Therefore, an individual trial of GH therapy may be appropriate in these patients. © 2015 S. Karger AG, Basel.

9.
N Engl J Med ; 366(5): 433-42, 2012 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-22296077

RESUMO

BACKGROUND: The 65-kD isoform of glutamic acid decarboxylase (GAD65) is a major autoantigen in type 1 diabetes. We hypothesized that alum-formulated GAD65 (GAD-alum) can preserve beta-cell function in patients with recent-onset type 1 diabetes. METHODS: We studied 334 patients, 10 to 20 years of age, with type 1 diabetes, fasting C-peptide levels of more than 0.3 ng per milliliter (0.1 nmol per liter), and detectable serum GAD65 autoantibodies. Within 3 months after diagnosis, patients were randomly assigned to receive one of three study treatments: four doses of GAD-alum, two doses of GAD-alum followed by two doses of placebo, or four doses of placebo. The primary outcome was the change in the stimulated serum C-peptide level (after a mixed-meal tolerance test) between the baseline visit and the 15-month visit. Secondary outcomes included the glycated hemoglobin level, mean daily insulin dose, rate of hypoglycemia, and fasting and maximum stimulated C-peptide levels. RESULTS: The stimulated C-peptide level declined to a similar degree in all study groups, and the primary outcome at 15 months did not differ significantly between the combined active-drug groups and the placebo group (P=0.10). The use of GAD-alum as compared with placebo did not affect the insulin dose, glycated hemoglobin level, or hypoglycemia rate. Adverse events were infrequent and mild in the three groups, with no significant differences. CONCLUSIONS: Treatment with GAD-alum did not significantly reduce the loss of stimulated C peptide or improve clinical outcomes over a 15-month period. (Funded by Diamyd Medical and the Swedish Child Diabetes Foundation; ClinicalTrials.gov number, NCT00723411.).


Assuntos
Peptídeo C/sangue , Diabetes Mellitus Tipo 1/tratamento farmacológico , Glutamato Descarboxilase/uso terapêutico , Adolescente , Autoanticorpos/sangue , Criança , Diabetes Mellitus Tipo 1/sangue , Diabetes Mellitus Tipo 1/imunologia , Feminino , Glutamato Descarboxilase/efeitos adversos , Glutamato Descarboxilase/imunologia , Humanos , Masculino , Isoformas de Proteínas , Adulto Jovem
10.
BMJ Case Rep ; 20092009.
Artigo em Inglês | MEDLINE | ID: mdl-21833343

RESUMO

16S rDNA polymerase chain reaction (PCR) in the diagnosis of fastidious organisms is becoming increasingly commonplace. We present the case of a child admitted to an acute paediatric unit of a university teaching hospital with otorrhoea, torticollis, and cervical lymphadenopathy. Examination revealed hepatosplenomegaly associated with pancytopenia. Radiological imaging confirmed a retropharyngeal abscess, bilateral mastoiditis, cerebellar lesions, and venous sinus thrombosis. Swabs of aural discharge grew anaerobes. Drainage of the retropharyngeal abscess and bilateral mastoidectomy were performed. Bone marrow aspiration was initially suspicious of acute leukaemia prompting further investigations, but cytogenetic analysis ruled out this diagnosis and changes were attributed to severe sepsis. Following 27 days of intravenous antibiotics and after clinical improvement, clindamycin was started. Intraoperative pus yielded no significant pathogens. A 16S rDNA PCR confirmed Fusobacterium necrophorum. The boy was discharged on a 6 week course of oral clindamycin.

11.
J Immunol ; 171(1): 438-46, 2003 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-12817028

RESUMO

Numerous studies indicate that enteroviruses, such as the Coxsackievirus (CV) group, are linked to autoimmune diseases. Virus tropism and tissue access are modulated by vascular endothelial cells (ECs), mainly at the level of the microvasculature. Data on the permissiveness of ECs to CV are, however, scanty and derived from studies on large vessel ECs. To examine the susceptibility of microvascular ECs to infection of group B CV (CVB), human dermal microvascular ECs (HMEC-1) were infected with three CVB strains, and the immunological phenotype of the infected cells was analyzed. All CVB persistently infected the EC cultures without producing overt cytopathic effects. Infected ECs retained endothelial characteristics. Release of infectious particles in cell supernatants persisted for up to 3 mo of culture. Infection up-regulated expression of the adhesion molecules ICAM-1 and VCAM-1, with the highest values detected during the first 30 days of infection (p < 0.05 vs uninfected HMEC-1). CVB infection increased production of the proinflammatory cytokines, IL-6, IL-8, and TNF-alpha, which may account for the enhanced expression of adhesion molecules. Parallel infection of macrovascular HUVEC had less evident effects on induction of ICAM-1 and did not significantly increase expression of VCAM-1. Moreover, mononuclear cell adhesion to CVB-infected HMEC-1 monolayers was increased, compared with uninfected monolayers. These results provide evidence that small vessel ECs can harbor a persistent viral infection, resulting in quantitative modification of adhesion molecule expression, which may contribute to the selective recruitment of subsets of leukocytes during inflammatory immune responses. Furthermore, our data confirm that the behavior against a viral challenge of ECs in large vessels and microvessels may differ.


Assuntos
Moléculas de Adesão Celular/biossíntese , Endotélio Vascular/imunologia , Endotélio Vascular/virologia , Enterovirus Humano B/imunologia , Enterovirus Humano B/patogenicidade , Regulação para Cima/imunologia , Adesão Celular/imunologia , Linhagem Celular , Linhagem Celular Transformada , Citocinas/biossíntese , Endotélio Vascular/metabolismo , Endotélio Vascular/patologia , Enterovirus Humano B/fisiologia , Humanos , Imunofenotipagem , Leucócitos Mononucleares/patologia , Leucócitos Mononucleares/virologia , Microcirculação/imunologia , Microcirculação/metabolismo , Microcirculação/patologia , Microcirculação/virologia , Monócitos/patologia , Monócitos/virologia , Linfócitos T/patologia , Linfócitos T/virologia , Células Tumorais Cultivadas , Replicação Viral/imunologia
12.
Diabetes ; 52(3): 717-25, 2003 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-12606513

RESUMO

Type 1 diabetes is characterized by T-cell infiltration of the islets of Langerhans and abundant HLA class II molecule expression on islet endothelial cells (ECs). The specificity of infiltrating T-cells for islet autoantigens has been amply demonstrated in animal models, and is implicit in human diabetes, but the processes regulating endothelial transmigration of islet autoantigen-specific T-cells into islets are not known. We examined the ability of ECs expressing HLA class II molecules to process and present the islet autoantigen GAD65 and examined the effects of presentation on transmigration of GAD65-specific T-cells. Primary cultures of human vascular ECs expressing the DRB1*0401 (VEC1) and DRB1*0301 (VEC2) genotypes were established and de novo expression of HLA class II molecules induced with interferon-gamma. Under these conditions, VEC1 efficiently processed and presented whole GAD65 to the HLA-DR4-restricted murine T-cell hybridoma T33.1 that recognizes the 274-286 epitope of GAD65. Using a transwell system, we examined the effect of GAD65 presentation on migration of GAD65-specific T-cells across EC monolayers. Migration of T33.1 hybridoma cells and of the human T-cell clone, PM1#11 (recognizes GAD65 epitope 339-352 presented by HLA-DR3) across VEC1 and VEC2, respectively, were greatly enhanced in the presence of GAD65, commencing more rapidly and achieving a higher peak migration at 3 h. Migrated PM1#11 cells retained full proliferative capacity. These results support the hypothesis that presentation of autoantigens by islet endothelium in vivo could promote transmigration of circulating islet autoantigen-specific T-cells primed in regional lymph nodes against islet autoantigens.


Assuntos
Apresentação de Antígeno/imunologia , Autoantígenos/imunologia , Endotélio Vascular/imunologia , Glutamato Descarboxilase/imunologia , Ilhotas Pancreáticas/imunologia , Isoenzimas/imunologia , Linfócitos T/imunologia , Sequência de Aminoácidos , Animais , Anticorpos Monoclonais , Aorta , Movimento Celular , Células Cultivadas , Citometria de Fluxo , Expressão Gênica , Genótipo , Antígenos HLA-DR/genética , Cadeias HLA-DRB1 , Antígenos de Histocompatibilidade Classe II/análise , Antígenos de Histocompatibilidade Classe II/genética , Humanos , Hibridomas/imunologia , Interferon gama/farmacologia , Camundongos , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/imunologia
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