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1.
Adv Clin Chem ; 93: 115-167, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31655729

RESUMO

The qualitative and quantitative determination of insulin and its related substances (e. g., C-peptide) is of great importance in many different areas of analytical chemistry. In particular, due to the steadily increasing prevalence of metabolic disorders such as diabetes mellitus, an adequate control of the circulating amount of insulin is desirable. In addition, also in forensics and doping control analysis, the determination of insulin in blood, urine or other biological matrices plays a major role. However, in order to establish general reference values for insulin and C-peptide for diabetology, the comparability of measured concentrations is indispensable. This has not yet been fully implemented, although enormous progress has been made in recent years, and the search for a "gold standard" method is still ongoing. In addition to established ligand-binding assays, an increasing number of mass-spectrometric methods have been developed and employed as the to-date available systems (for example, high-resolution/high accuracy mass spectrometers) provide the sensitivity required to determine analyte concentrations in the sub-ng/mL (sub-100pmol/L) level. Meanwhile, also high-throughput measurements have been realized to meet the requirement of testing a high number of samples in a short period of time. Further developments aim at enabling the online measurement of insulin in the blood with the help of an insulin sensor and, in the following, in addition to a brief review, today's state of the art testing developments are summarized.


Assuntos
Líquidos Corporais/metabolismo , Insulina/metabolismo , Sequência de Aminoácidos , Peptídeo C/metabolismo , Medicina Legal , Humanos , Insulina/sangue , Insulina/normas , Insulina/urina , Limite de Detecção , Espectrometria de Massas
2.
Acta Diabetol ; 56(11): 1225-1230, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31367990

RESUMO

AIMS: To investigate the possibility of identifying a subtype of latent autoimmune diabetes in adults (LADA), T-LADA (T cell responses-positive and autoantibody-negative) from patients with phenotypic type 2 diabetes (T2D) by enzyme-linked immunospot (ELISPOT). METHODS: Eighty-two patients with phenotypic T2D were studied. Autoantibodies against glutamic acid decarboxylase (GAD), insulinoma-associated protein-2 and zinc transporter 8 were measured by radioligand assay. Thirty-nine Ab+ and 43 Ab- patients with phenotypic T2D were enrolled for T cell assay of responses to GAD65 and C-peptide antigen by ELISPOT. RESULTS: (1) Eleven of 43 Ab- participants with phenotypic T2D were demonstrated interferon (IFN)-γ secreting T cells by ELISPOT, while 13 of 39 Ab+ patients with phenotypic T2D were positive for T cells responses to islet antigens. (2) The onset ages of T cell+ people with phenotypic T2D were younger than that of T cell- individuals (42.7 ± 9.3 vs. 48.2 ± 10.2 years, P = 0.025). Moreover, T cell+ patients with T2D displayed a significantly lower fasting C-peptide (FCP) compared with T cell- participants [0.28 (0.02-0.84) vs. 0.42 (0.05-1.26) nmol/L, P = 0.013]. (3) Ab-T+ group had a significantly lower FCP compared with Ab-T- group [0.31 (0.13-0.84) vs. 0.51 (0.07-1.26) nmol/L, P = 0.023]. CONCLUSIONS: By measuring T cell responses to islet antigens in patients with phenotypic T2D, we identified a specific subtype of LADA who may be associated with worse basal ß-cell function than classic T2D (Ab-T-).


Assuntos
Diabetes Mellitus Tipo 2/imunologia , Diabetes Autoimune Latente em Adultos/imunologia , Fenótipo , Linfócitos T/imunologia , Adulto , Autoanticorpos/imunologia , Peptídeo C/metabolismo , Diabetes Mellitus Tipo 2/sangue , Feminino , Glutamato Descarboxilase/imunologia , Humanos , Diabetes Autoimune Latente em Adultos/sangue , Diabetes Autoimune Latente em Adultos/classificação , Masculino , Pessoa de Meia-Idade , Transportador 8 de Zinco/imunologia
3.
In Vitro Cell Dev Biol Anim ; 55(6): 453-461, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31140102

RESUMO

Although bone marrow-derived mesenchymal stem cells (BMSCs) have been reported to be effective for the attenuation of diabetes, they have limitations. Whether BMSCs can be target-induced by pancreatic stem cells (PSCs) to have effectiveness for the restoration of diabetic islet injury was unknown. In this study, based on their successful isolation and cultivation, BMSCs were co-cultured with PSCs. The pancreatic stem cells markers, Nestin and Neurogenin3 in co-cultured BMSCs were detected to evaluate the target-induction effects. After the diabetic rats were intravenously injected with the target-induced BMSCs, general indicators and islet morphology were detected. The islet insulin generation, and serum insulin and C-peptide contents were measured. It was found that after co-culture, the mRNA expressions, protein contents and distributions of Nestin and Neurogenin3, were dramatically high in BMSCs, indicating that they were successfully target-induced to pancreatic stem-like cells. Furthermore, the target-induced BMSCs had beneficial effects on serum glycated albumin levels and glycogen contents as well as islet morphology of the diabetic rats. Besides elevation of islet insulin generation, the target-induced BMSCs had significant effect on serum insulin and C-peptide contents. In conclusion, BMSCs could be target-induced by PSCs to have effectiveness on the pancreatic restoration of diabetic rats.


Assuntos
Diabetes Mellitus Experimental/terapia , Ilhotas Pancreáticas/patologia , Transplante de Células-Tronco Mesenquimais/métodos , Células-Tronco Mesenquimais/fisiologia , Pâncreas/citologia , Animais , Animais Recém-Nascidos , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Células da Medula Óssea/citologia , Peptídeo C/metabolismo , Técnicas de Cocultura , Diabetes Mellitus Experimental/patologia , Glicogênio/metabolismo , Insulina/metabolismo , Ilhotas Pancreáticas/metabolismo , Masculino , Células-Tronco Mesenquimais/citologia , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/metabolismo , Nestina/genética , Nestina/metabolismo , Ratos Sprague-Dawley , Albumina Sérica/análise , Albumina Sérica/metabolismo , Células-Tronco/citologia
4.
J Genet ; 982019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30945665

RESUMO

Insulin is a commonly used measure of pancreatic ß-cell function but exhibits a short half-life in the human body. During biosynthesis, insulin release is accompanied by C-peptide at an equimolar concentration which has a much higher plasma half-life and is therefore projected as a precise measure of ß-cell activity than insulin. Despite this, genetic studies of metabolic traits haveneglected the regulatory potential of C-peptide for therapeutic intervention of type-2 diabetes. The present study is aimed to search genomewide variants governing C-peptide levels in genetically diverse and high risk population for metabolic diseases-Indians. We performed whole genome genotyping in 877 healthy Indians of Indo-European origin followed by replication of variants with P ≤ 1 × 10-3 in an independent sample-set of 1829 Indians. Lead-associated signals were also tested in-silico in 773 Hispanics. To secure biological rationale for observed association, we further carried out DNA methylation quantitative trait loci analysis in 233 Indians and publicly available regulatory data was mined. We discovered novel lncRNA gene AC073333.8 with the strongest association with C-peptide levels in Indians that however missed genomewide significance. Also, noncoding genes, RP1-209A6.1 and RPS3AP5; protein gene regulators, ZNF831 and ETS2; and solute carrier protein gene SLC15A5 retained robust association with C-peptide after meta-analysis. Integration of methylation data revealed ETS2 and ZNF831 single-nucleotide polymorphisms as significant meth-QTLs in Indians. All genes showed reasonable expression in the human lung, signifying alternate important organs for C-peptide biology. Our findings mirror polygenic nature of C-peptide where multiple small-effect size variants in the regulatory genome principally govern the trait biology.


Assuntos
Biomarcadores/metabolismo , Peptídeo C/metabolismo , Diabetes Mellitus Tipo 2/genética , Genoma Humano , Estudo de Associação Genômica Ampla , Polimorfismo de Nucleotídeo Único , Adolescente , Adulto , Grupo com Ancestrais do Continente Asiático , Criança , Pré-Escolar , Diabetes Mellitus Tipo 2/metabolismo , Feminino , Predisposição Genética para Doença , Genótipo , Humanos , Masculino , Fenótipo , Locos de Características Quantitativas , Adulto Jovem
5.
Diabetes ; 68(6): 1267-1276, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30967424

RESUMO

A three-arm, randomized, double-masked, placebo-controlled phase 2b trial performed by the Type 1 Diabetes TrialNet Study Group previously demonstrated that low-dose anti-thymocyte globulin (ATG) (2.5 mg/kg) preserved ß-cell function and reduced HbA1c for 1 year in new-onset type 1 diabetes. Subjects (N = 89) were randomized to 1) ATG and pegylated granulocyte colony-stimulating factor (GCSF), 2) ATG alone, or 3) placebo. Herein, we report 2-year area under the curve (AUC) C-peptide and HbA1c, prespecified secondary end points, and potential immunologic correlates. The 2-year mean mixed-meal tolerance test-stimulated AUC C-peptide, analyzed by ANCOVA adjusting for baseline C-peptide, age, and sex (n = 82) with significance defined as one-sided P < 0.025, was significantly higher in subjects treated with ATG versus placebo (P = 0.00005) but not ATG/GCSF versus placebo (P = 0.032). HbA1c was significantly reduced at 2 years in subjects treated with ATG (P = 0.011) and ATG/GCSF (P = 0.022) versus placebo. Flow cytometry analyses demonstrated reduced circulating CD4:CD8 ratio, increased regulatory T-cell:conventional CD4 T-cell ratios, and increased PD-1+CD4+ T cells following low-dose ATG and ATG/GCSF. Low-dose ATG partially preserved ß-cell function and reduced HbA1c 2 years after therapy in new-onset type 1 diabetes. Future studies should determine whether low-dose ATG might prevent or delay the onset of type 1 diabetes.


Assuntos
Soro Antilinfocitário/uso terapêutico , Diabetes Mellitus Tipo 1/tratamento farmacológico , Fatores Imunológicos/uso terapêutico , Adolescente , Adulto , Peptídeo C/metabolismo , Relação CD4-CD8 , Criança , Diabetes Mellitus Tipo 1/imunologia , Diabetes Mellitus Tipo 1/metabolismo , Método Duplo-Cego , Feminino , Citometria de Fluxo , Hemoglobina A Glicada/metabolismo , Fator Estimulador de Colônias de Granulócitos/uso terapêutico , Humanos , Masculino , Linfócitos T Reguladores/imunologia , Adulto Jovem
6.
Am J Physiol Endocrinol Metab ; 316(5): E687-E694, 2019 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-30807214

RESUMO

The characteristics of pulsatile insulin secretion are important determinants of type 2 diabetes pathophysiology, but they are understudied due to the difficulties in measuring pulsatile insulin secretion noninvasively. Deconvolution of either peripheral C-peptide or insulin concentrations offers an appealing alternative to hepatic vein catheterization. However, to do so, there are a series of methodological challenges to overcome. C-peptide has a relatively long half-life and accumulates in the circulation. On the other hand, peripheral insulin concentrations reflect relatively fast clearance and hepatic extraction as it leaves the portal circulation to enter the systemic circulation. We propose a method based on nonparametric stochastic deconvolution of C-peptide concentrations, using individually determined C-peptide kinetics, to overcome these limitations. The use of C-peptide (instead of insulin) concentrations allows estimation of portal (and not post-hepatic) insulin pulses, whereas nonparametric stochastic deconvolution allows evaluation of pulsatile signals without any a priori assumptions of pulse shape and occurrence. The only assumption required is the degree of smoothness of the (unknown) secretion rate. We tested this method first on simulated data and then on 29 nondiabetic subjects studied during euglycemia and hyperglycemia and compared our estimates with the profiles obtained from hepatic vein insulin concentrations. This method produced satisfactory results both in the ability to fit the data and in providing reliable estimates of pulsatile secretion, in agreement with hepatic vein measurements. In conclusion, the proposed method enables reliable and noninvasive measurement of pulsatile insulin secretion. Future studies will be needed to validate this method in people with type 2 diabetes.


Assuntos
Peptídeo C/sangue , Hiperglicemia/sangue , Secreção de Insulina/fisiologia , Insulina/sangue , Adulto , Peptídeo C/metabolismo , Simulação por Computador , Diabetes Mellitus Tipo 2/metabolismo , Feminino , Glucose/metabolismo , Voluntários Saudáveis , Veias Hepáticas , Humanos , Hiperglicemia/metabolismo , Insulina/metabolismo , Cinética , Masculino , Pessoa de Meia-Idade , Estatísticas não Paramétricas
7.
Eur J Med Res ; 24(1): 13, 2019 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-30782217

RESUMO

BACKGROUND: Some studies have suggested that blood glucose fluctuation and C-peptide level were considered as predictive factors for carotid artery intima-media thickness (CIMT). However, the relationships of these variables are unclear. This research was aimed to identify the potential effects of blood glucose fluctuation, C-peptide level and conventional risk factors on CIMT. METHODS: A total of 280 type 2 diabetes mellitus (T2DM) patients were enrolled into this study. Population characteristics were obtained through medical history and clinical parameters. The patients were divided into two groups according to the critical value of CIMT (0.9). Research data were analyzed to identify risk factors of CIMT between the two groups. RESULTS: The comparison results of basic information showed that differences in age and illness years between the two groups were statistically significant (p = 0.0002 and p = 0.0063). Logistic regression analysis results indicated that smoking, uric acid (UA) levels, 2 h C-peptide and standard deviation of blood glucose (SDBG) were the influence factors for CIMT thickening (p = 0.032, p = 0.047, p = 0.049 and p = 0.042, respectively). Blood glucose fluctuation could affect the risk of some complications. In largest amplitude of glycemic excursions (LAGE) > 4.4 group, the CIMT abnormal rate was 27.10%, which was significantly higher than 12.12% in the LAGE ≤ 4.4 group (p = 0.012). The CIMT abnormal rate of SDBG > 2.0 group was 27.81%, which was significantly higher than that of the SDBG ≤ 2.0 group (p = 0.018). CONCLUSIONS: Blood glucose fluctuation is an independent risk factor associated with CIMT in T2DM patients, in addition to conventional risk factors, such as smoking, high UA level and 2 h C-peptide. Therefore, more attention should be given to the change of CIMT and the complications.


Assuntos
Grupo com Ancestrais do Continente Asiático , Glicemia/metabolismo , Peptídeo C/metabolismo , Espessura Intima-Media Carotídea , Diabetes Mellitus Tipo 2/sangue , Grupos Étnicos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fatores de Risco
8.
Diabetes Res Clin Pract ; 149: 9-17, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30710658

RESUMO

Published information on diabetes in Pakistani youth is limited. We aimed to investigate the demographic, clinical, and biochemical features, and HLA-DRB1 alleles in new cases of diabetes affecting children and adolescents <22 years of age. The study was conducted at Baqai Institute of Diabetology and Endocrinology in Karachi from June 2013-December 2015. One hundred subjects aged <22 years at diagnosis were enrolled. Demographic characteristics, clinical information, biochemical parameters (blood glucose, HbA1c, C-peptide, glutamic acid decarboxylase 65 (GAD65) and islet antigen 2 (IA-2) autoantibodies) were measured. DNA from 100 subjects and 200 controls was extracted and genotyped for HLA-DRB1 using high-resolution genotyping technology. Ninety-nine subjects were clinically diagnosed as type 1 diabetes (T1D) and one as type 2 diabetes (T2D). Of the 99 with T1D, 57 (57.6%) were males and 42 (42.4%) females, with mean age at diagnosis 11.0 ±â€¯5.2 years (range 1.6-21.7 years) and peaks at six and fifteen years. Fifty-seven subjects were assessed within one month of diagnosis and all within eleven months. For the subjects diagnosed as T1D, mean C-peptide was 0.63 ±â€¯0.51 nmol/L (1.91 ±â€¯1.53 ng/mL), with 16 (16.2%) IA2 positive, 53 (53.5%) GAD-65 positive, and 10 (10.1%) positive for both autoantibodies. In T1D patients, the allele DRB1*03:01 demonstrated highly significant T1D association (p < 10-16), with no apparent risk conferred by DRB1*04:xx alleles. CONCLUSIONS: Heterogeneous forms of T1D appear more common in children and youth in Pakistan than in European populations. Individual understanding of such cases could enable improved management strategies and healthier outcomes.


Assuntos
Autoanticorpos/metabolismo , Peptídeo C/metabolismo , Diabetes Mellitus Tipo 1/genética , Cadeias HLA-DRB1/genética , Adolescente , Adulto , Criança , Pré-Escolar , Diabetes Mellitus Tipo 1/patologia , Feminino , Cadeias HLA-DRB1/metabolismo , Humanos , Lactente , Masculino , Paquistão , Adulto Jovem
9.
J Ethnopharmacol ; 234: 172-179, 2019 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-30660712

RESUMO

ETHNOPHARMACOLOGICAL RELEVANCE: Mistletoe (Viscum album), an evergreen parasitic plant, has been widely used as an oriental phytomedicine to treat diabetes mellitus. However, it is unknown which mistletoe constituent exerts the beneficial effect against the disease. In this study, we examined the hypoglycemic activity of mistletoe and investigated whether the polypeptide viscothionin, purified from mistletoe, was responsible for the activity. MATERIALS AND METHODS: Mistletoe extracts were prepared by heating mistletoe powder made of leaves and twigs in water for 3, 6, 9, and 12 h. Rat insulinoma RINm5F cells were used to test the cytotoxicity of the extracts and their effects on the secretion of insulin and its precursor, C-peptide. The inhibitory effects of a mistletoe extract on glucose absorption were measured using an α-glucosidase inhibition assay. To determine the component of mistletoe responsible for the observed effects, the mistletoe extract was precipitated with ethanol or hydrolyzed with a protease for further testing. A potential active constituent of mistletoe was isolated by chromatography and molecular weight cut-off fractionation, and its ability to induce insulin secretion was investigated. RESULTS: A 12-h heat-treated mistletoe extract, showing no cytotoxicity, significantly increased the secretion of insulin and C-peptide by RINm5F cells and enhanced the expression of glucose transporter type 4 (GLUT-4), insulin receptor substrate 1 (IRS-1), and protein kinase B (also known as AKT) in differentiated C2C12 cells. The extract also inhibited α-glucosidase activity. After ethanol precipitation, the extract showed much stronger effects on insulin- and C-peptide-secreting activities of cells, whereas the enzyme-hydrolyzed extract was less effective than the original extract, suggesting that the effect was mediated by a proteinaceous constituent of mistletoe. Subsequent analysis showed that viscothionin, a heat-stable 6-kDa polypeptide isolated from mistletoe, increased the level of insulin secretion by more than 20-fold compared to that induced by the extract. CONCLUSIONS: Our study indicates that the hypoglycemic effect of mistletoe is mediated by its insulinotropic action and α-glucosidase inhibitory activity, and the effect is due to viscothionin, one of the major bioactive constituents of mistletoe.


Assuntos
Secreção de Insulina/efeitos dos fármacos , Células Secretoras de Insulina/efeitos dos fármacos , Peptídeos/farmacologia , Viscum album/química , Animais , Peptídeo C/metabolismo , Linhagem Celular Tumoral , Glucose/metabolismo , Hipoglicemiantes/isolamento & purificação , Hipoglicemiantes/farmacologia , Células Secretoras de Insulina/metabolismo , Insulinoma/metabolismo , Camundongos , Mioblastos/efeitos dos fármacos , Mioblastos/metabolismo , Peptídeos/isolamento & purificação , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Ratos , Fatores de Tempo
10.
PLoS One ; 14(1): e0211210, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30682116

RESUMO

It remains widely perceived that early-onset Type 2 Diabetes (T2D) in children and adolescents is rare and clinically distinct from Type 1 Diabetes (T1D). We studied the challenges of classifying subtypes of early-onset diabetes using clinical features and biomarkers, and management of these patients. We reviewed retrospectively the record of patients < 25 years old who attended the diabetes clinic in Penang General Hospital, Malaysia between 1st December 2012 and 30th June 2015. We examined their clinical features, C-peptide and pancreatic autoantibodies. Comparisons were made between T1D and T2D for magnitude, demographics, metabolic status and complications. We studied 176 patients with a mean age of 20 ± 3.7 years, 43.2% had T1D, 13.6% had T2D, and 13.6% had mixed features of both. When tested, pancreatic autoantibodies were positive in 59.4% of the T1D. T2D presented two years later than T1D at 14.3 years, 20% were asymptomatic at presentation, and 50% required insulin supplementation despite fasting c-peptide of > 250 pmol/L. HbA1C of ≤ 8.0% (64 mmol/mol) was achieved in 30.3% of T1D, 58.3% of T2D on OAD and 16.7% of T2D on insulin. The T2D had greater cardiovascular risk with higher body mass index, more dyslipidaemia, higher blood pressure and earlier onset of nephropathy. The overlapping clinical features, variable autoimmunity, and beta-cell loss complicate classification of young diabetes. Pancreatic autoantibodies and C-peptide did not always predict diabetes subtypes nor respond to insulin. The poor metabolic control and high cardiovascular risk burden among the T2D highlight the need for population-based study and focused intervention.


Assuntos
Autoanticorpos/metabolismo , Peptídeo C/metabolismo , Diabetes Mellitus Tipo 1/epidemiologia , Diabetes Mellitus Tipo 2/epidemiologia , Pâncreas/imunologia , Adolescente , Idade de Início , Doenças Cardiovasculares/etiologia , Criança , Diabetes Mellitus Tipo 1/complicações , Diabetes Mellitus Tipo 1/metabolismo , Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/metabolismo , Feminino , Humanos , Malásia/etnologia , Masculino , Estudos Retrospectivos , Adulto Jovem
11.
Matrix Biol ; 80: 46-58, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-30196101

RESUMO

Hyaluronan (HA), an extracellular matrix glycosaminoglycan, is implicated in the pathogenesis of both type 1 diabetes (T1D) as well as type 2 diabetes (T2D) and has been postulated to be increased in these diseases due to hyperglycemia. We have examined the serum and tissue distribution of HA in human subjects with T1D and T2D and in mouse models of these diseases and evaluated the relationship between HA levels and glycemic control. We found that serum HA levels are increased in T2D but not T1D independently of hemoglobin-A1c, C-peptide, body mass index, or time since diabetes diagnosis. HA is likewise increased in skeletal muscle in T2D subjects relative to non-diabetic controls. Analogous increases in serum and muscle HA are seen in diabetic db/db mice (T2D), but not in diabetic DORmO mice (T1D). Diabetes induced by the ß-cell toxin streptozotozin (STZ) lead to an increase in blood glucose but not to an increase in serum HA. These data indicate that HA levels are increased in multiple tissue compartments in T2D but not T1D independently of glycemic control. Given that T2D but not T1D is associated with systemic inflammation, these patterns are consistent with inflammatory factors and not hyperglycemia driving increased HA. Serum HA may have value as a biomarker of systemic inflammation in T2D.


Assuntos
Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Tipo 1/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Ácido Hialurônico/sangue , Músculo Esquelético/metabolismo , Adulto , Animais , Índice de Massa Corporal , Peptídeo C/metabolismo , Diabetes Mellitus Experimental/sangue , Diabetes Mellitus Tipo 1/sangue , Diabetes Mellitus Tipo 2/sangue , Feminino , Hemoglobina A Glicada/metabolismo , Humanos , Ácido Hialurônico/metabolismo , Masculino , Camundongos , Estreptozocina , Adulto Jovem
12.
Pediatr Diabetes ; 20(2): 166-171, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30556344

RESUMO

BACKGROUND: Stimulated C-peptide measurement after a mixed meal tolerance test (MMTT) is the accepted gold standard for assessing residual beta-cell function in type 1 diabetes (T1D); however, this approach is impractical outside of clinical trials. OBJECTIVE: To develop an improved estimate of residual beta-cell function in children with T1D using commonly measured clinical variables. SUBJECTS/METHODS: A clinical model to predict 90-minute MMTT stimulated C-peptide in children with recent-onset T1D was developed from the combined AbATE, START, and TIDAL placebo subjects (n = 46) 6 months post-recruitment using multiple linear regression. This model was then validated in a clinical cohort (Hvidoere study group, n = 262). RESULTS: A model of estimated C-peptide at 6 months post-diagnosis, which included age, gender, body mass index (BMI), hemoglobin A1c (HbA1c), and insulin dose predicted 90-minute stimulated C-peptide measurements (adjusted R2 = 0.63, P < 0.0001). The predictive value of insulin dose and HbA1c alone (IDAA1c) for 90-minute stimulated C-peptide was significantly lower (R2 = 0.37, P < 0.0001). The slopes of linear regression lines of the estimated and stimulated 90-minute C-peptide levels obtained at 6 and 12 months post diagnosis in the Hvidoere clinical cohort were R2 = 0.36, P < 0.0001 at 6 months and R2 = 0.37, P < 0.0001 at 12 months. CONCLUSIONS: A clinical model including age, gender, BMI, HbA1c, and insulin dose predicts stimulated C-peptide levels in children with recent-onset T1D. Estimated C-peptide is an improved surrogate to monitor residual beta-cell function outside clinical trial settings.


Assuntos
Peptídeo C/metabolismo , Diabetes Mellitus Tipo 1/diagnóstico , Diabetes Mellitus Tipo 1/tratamento farmacológico , Diabetes Mellitus Tipo 1/metabolismo , Células Secretoras de Insulina/fisiologia , Modelos Biológicos , Adolescente , Adulto , Idade de Início , Anticorpos Monoclonais Humanizados/uso terapêutico , Criança , Estudos de Coortes , Diabetes Mellitus Tipo 1/epidemiologia , Feminino , Humanos , Secreção de Insulina/fisiologia , Células Secretoras de Insulina/patologia , Masculino , Prognóstico , Indução de Remissão , Resultado do Tratamento , Adulto Jovem
13.
Diabetes Metab Res Rev ; 35(1): e3071, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30160822

RESUMO

C-peptide is a cleavage product of proinsulin that acts on different type of cells, such as blood and endothelial cells. C-peptide biological effects may be different in type 1 and type 2 diabetes. Besides, there are further evidence for a functional interaction between C-peptide and insulin. In this way, C-peptide has ambiguous effects, acting as an antithrombotic or thrombotic molecule, depending on the physiological environment and disease conditions. Moreover, C-peptide regulates interaction of leucocytes, erythrocytes, and platelets with the endothelium. The beneficial effects include stimulation of nitric oxide production with its subsequent release by platelets and endothelium, the interaction with erythrocytes leading to the generation of adenosine triphosphate, and inhibition of atherogenic cytokine release. The undesirable action of C-peptide includes the chemotaxis of monocytes, lymphocytes, and smooth muscle cells. Also, C-peptide was related with increased lipid deposits and elevated smooth muscle cells proliferation in the vessel wall, contributing to atherosclerosis. Purpose of this review is to explore these dual roles of C-peptide on the blood, contributing at one side to haemostasis and the other to atherosclerotic process.


Assuntos
Aterosclerose/metabolismo , Peptídeo C/metabolismo , Diabetes Mellitus Tipo 1/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Animais , Endotélio Vascular/metabolismo , Eritrócitos/metabolismo , Humanos , Óxido Nítrico/metabolismo
14.
Nutrients ; 10(12)2018 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-30558330

RESUMO

Several studies have linked increased intake of dietary fibre to improvement in the management of body weight. Dietary fibre from resistant starch (RS) has been shown to have an impact on food intake in normal weight individuals, but its role in obesity is unknown. The present study aimed to investigate the short-term effects of RS on appetite, satiety and postprandial metabolism in overweight/obese subjects. In this single-blind randomized crossover study, overweight/obese healthy males consumed a test breakfast and lunch containing either 48 g RS or a placebo. Postprandial qualitative appetite, glucose, insulin, and GLP-1 were measured every 30 min for 7 h. Energy intake values from an ad libitum dinner and for a 24-h period were assessed. Acute consumption of RS at breakfast/lunch significantly reduced the energy intake at the ad libitum dinner (p = 0.017). No significant effect over 24 h or qualitative feelings of satiety were observed. Significant treatment × time effects were found for postprandial glucose (p = 0.004) for RS compared to placebo, with a trend for higher C-peptide concentrations following RS. The postprandial insulin and GLP-1 responses were not significantly different. RS may indeed have short-term beneficial effects in obese individuals.


Assuntos
Apetite/efeitos dos fármacos , Fibras na Dieta/farmacologia , Ingestão de Alimentos/efeitos dos fármacos , Ingestão de Energia/efeitos dos fármacos , Obesidade , Saciação/efeitos dos fármacos , Amido/farmacologia , Adolescente , Adulto , Glicemia/metabolismo , Índice de Massa Corporal , Peptídeo C/metabolismo , Estudos Cross-Over , Fibras na Dieta/uso terapêutico , Peptídeo 1 Semelhante ao Glucagon/sangue , Humanos , Insulina/sangue , Masculino , Refeições , Obesidade/sangue , Obesidade/dietoterapia , Sobrepeso , Período Pós-Prandial , Método Simples-Cego , Amido/uso terapêutico , Adulto Jovem
15.
PLoS One ; 13(11): e0207065, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30412637

RESUMO

AIMS: Increased proinsulin (PI) compared to C-peptide (CP) concentrations have been reported, both prior to type 1 diabetes mellitus (T1D) onset, as well as early in disease. In this pilot study, we sought to define the normal PI secretion in a healthy cohort and compare this to a local T1D cohort and a separate well-defined nationally representative T1D cohort with measurable CP. METHODS: Thirteen healthy subjects and 12 T1D subjects with T1D >3 years from the local T1D cohort completed mixed meal tolerance tests (MMTT) with PI and CP measured over 90 and 240 minutes. The change in CP (maximum versus baseline, ΔCP) during MMTT in the T1D Exchange T1D cohort was stratified according to non-fasting PI concentrations, based on a fasting PI threshold, as defined by the healthy control group. RESULTS: The maximum fasting PI in the control group was 6 pmol/L. Individuals from the T1D Exchange with a non-fasting PI ≥ 6 pmol/L had a lower ΔCP during a MMTT, compared to those with a PI < 6 pmol/L. While only three individuals from the local T1D cohort had measurable CP and PI during the MMTT, those with a greater ΔCP had lower PI secretion. CONCLUSION: While all T1D subjects from the T1D Exchange secreted measurable non-fasting PI, those with a greater non-fasting PI demonstrated a decrease in ΔCP during the MMTT. PI may be preferentially secreted compared to CP in some individuals with long standing T1D.


Assuntos
Peptídeo C/metabolismo , Diabetes Mellitus Tipo 1/metabolismo , Proinsulina/metabolismo , Adolescente , Adulto , Idoso , Glicemia/metabolismo , Estudos de Casos e Controles , Estudos de Coortes , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Projetos Piloto , Adulto Jovem
16.
Proc Natl Acad Sci U S A ; 115(42): 10732-10737, 2018 10 16.
Artigo em Inglês | MEDLINE | ID: mdl-30275329

RESUMO

Type 1 diabetes (T1D) is an autoimmune disease in which insulin-producing beta cells, found within the islets of Langerhans in the pancreas, are destroyed by islet-infiltrating T cells. Identifying the antigenic targets of beta-cell reactive T cells is critical to gain insight into the pathogenesis of T1D and develop antigen-specific immunotherapies. Several lines of evidence indicate that insulin is an important target of T cells in T1D. Because many human islet-infiltrating CD4+ T cells recognize C-peptide-derived epitopes, we hypothesized that full-length C-peptide (PI33-63), the peptide excised from proinsulin as it is converted to insulin, is a target of CD4+ T cells in people with T1D. CD4+ T cell responses to full-length C-peptide were detected in the blood of: 14 of 23 (>60%) people with recent-onset T1D, 2 of 15 (>13%) people with long-standing T1D, and 1 of 13 (<8%) HLA-matched people without T1D. C-peptide-specific CD4+ T cell clones, isolated from six people with T1D, recognized epitopes from the entire 31 amino acids of C-peptide. Eighty-six percent (19 of 22) of the C-peptide-specific clones were restricted by HLA-DQ8, HLA-DQ2, HLA-DQ8trans, or HLA-DQ2trans, HLA alleles strongly associated with risk of T1D. We also found that full-length C-peptide was a much more potent agonist of some CD4+ T cell clones than an 18mer peptide encompassing the cognate epitope. Collectively, our findings indicate that proinsulin C-peptide is a key target of autoreactive CD4+ T cells in T1D. Hence, full-length C-peptide is a promising candidate for antigen-specific immunotherapy in T1D.


Assuntos
Autoantígenos/imunologia , Peptídeo C/imunologia , Peptídeo C/metabolismo , Linfócitos T CD4-Positivos/imunologia , Diabetes Mellitus Tipo 1/diagnóstico , Antígenos HLA/imunologia , Ilhotas Pancreáticas/imunologia , Proinsulina/imunologia , Adolescente , Adulto , Células Cultivadas , Criança , Pré-Escolar , Diabetes Mellitus Tipo 1/imunologia , Diabetes Mellitus Tipo 1/metabolismo , Humanos , Pessoa de Meia-Idade , Adulto Jovem
17.
Gene ; 675: 165-175, 2018 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-30180963

RESUMO

BACKGROUND: The present study has been aimed to identify molecular dynamics of pancreatic transcription factors (pTFs) during events of directed trans-differentiation of human hepatic progenitor cells (hHPCs) into insulin producing cells (InPCs) within bioengineered humanized neoorgan. The study demonstrates applicability of acellularized whole splenic scaffold (ASOS) to generate insulin producing humanized transplantable neoorgan through activation of pancreatic transcription factors. METHODS: An efficient acellularization process was developed for xenogeneic rat spleen using change in different gradients of reagents perfusion through splenic artery for varying time points. The acellularized xenogeneic spleen scaffold was characterized thoroughly for preservation of extra-cellular matrix and retention of organ specific vasculature and mechanical properties. Further scaffolds were sterilized and repopulated with hHPCs which were triggered using a stage wise induction with growth factors and hyperglycemic challenge for trans-differentiation into InPCs. Dynamics of pTFs alone or simultaneously during induction process was identified using gene expression analysis and immunological staining. RESULTS: The cells within the engineered neoorgan respond to growth factors and extrinsic hyperglycemic challenge and generate large number of InPCs under controlled dynamic regulation of pTFs. Highly controlled regulation of pTFs generates higher percentage of Nkx-6.1+/C-peptide+ cells within the engineered splenic scaffolds. Generation of high percentage of insulin and C-peptide positive cells in three-dimensional organ architecture responded better to hyperglycemic stimuli and produced higher quantity of insulin than 2D-culture system. CONCLUSION: The present study provides a novel platform for designing effective regenerative strategies using whole organ scaffolds to control hyperglycemia under tight regulation of pTFs using humanized neoorgan system.


Assuntos
Células Secretoras de Insulina/metabolismo , Insulina/metabolismo , Engenharia Tecidual/métodos , Fatores de Transcrição/metabolismo , Animais , Peptídeo C/genética , Peptídeo C/metabolismo , Diferenciação Celular , Proteínas de Homeodomínio/genética , Proteínas de Homeodomínio/metabolismo , Humanos , Hiperglicemia/metabolismo , Simulação de Dinâmica Molecular , Ratos , Baço/citologia , Transplante de Células-Tronco , Células-Tronco/citologia , Células-Tronco/metabolismo , Técnicas de Cultura de Tecidos , Tecidos Suporte , Transativadores/genética , Transativadores/metabolismo , Fatores de Transcrição/genética
18.
Transplantation ; 102(11): 1857-1863, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30063695

RESUMO

BACKGROUND: It has been proposed that islet transplants comprised primarily of small rather than large islets may provide better graft function, due to their lower susceptibility to hypoxic damage. Our aim was to determine whether islet size correlated with in vivo graft function in islet transplant recipients with C peptide-negative type 1 diabetes when islets have undergone pretransplant islet culture. METHODS: Human pancreatic islets were isolated, cultured for 24 hours and infused by standardized protocols. Ninety-minute stimulated C-peptide concentrations were determined during a standard meal tolerance test 3 months posttransplant. The islet isolation index (IEq/islet number) was determined immediately after isolation and again before transplantation (after tissue culture). This was correlated with patient insulin requirement or stimulated C-peptide. RESULTS: Changes in insulin requirement did not significantly correlate with islet isolation index. Stimulated C-peptide correlated weakly with IEq at isolation (P = 0.40) and significantly with IEq at transplantation (P = 0.018). Stimulated C-peptide correlated with islet number at isolation (P = 0.013) and more strongly with the islet number at transplantation (P = 0.001). In contrast, the correlation of stimulated C-peptide and islet isolation index was weaker (P = 0.018), and this was poorer at transplantation (P = 0.034). Using linear regression, the strongest association with graft function was islet number (r = 0.722, P = 0.001). Islet size was not related to graft function after adjusting for islet volume or number. CONCLUSIONS: These data show no clear correlation between islet isolation index and graft function; both small and large islets are suitable for transplantation, provided the islets have survived a short culture period postisolation.


Assuntos
Diabetes Mellitus Tipo 1/cirurgia , Transplante das Ilhotas Pancreáticas , Ilhotas Pancreáticas/cirurgia , Adulto , Peptídeo C/metabolismo , Diabetes Mellitus Tipo 1/sangue , Diabetes Mellitus Tipo 1/diagnóstico , Feminino , Sobrevivência de Enxerto , Humanos , Hipoglicemiantes/administração & dosagem , Insulina/administração & dosagem , Ilhotas Pancreáticas/citologia , Ilhotas Pancreáticas/metabolismo , Masculino , Pessoa de Meia-Idade , Fatores de Tempo , Técnicas de Cultura de Tecidos , Resultado do Tratamento
19.
Medicine (Baltimore) ; 97(32): e11783, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30095635

RESUMO

The purpose of the study was to test the hypothesis that anemia is related with serum C-peptide concentrations in individuals with type 2 diabetes mellitus (DM).This cross-sectional study was carried out in 1300 individuals with type 2 DM. We measured fasting C-peptide, 2-hour postprandial C-peptide, and postprandial C-peptide minus fasting C-peptide (ΔC-peptide) concentrations. Anemia was defined as hemoglobin (Hb) concentrations <130 g/L in men and <120 g/L in women. Anemia was graded into 2 groups: grade I anemia of Hb concentrations ≥110 g/L and grade II anemia of Hb concentrations <110 g/L.Fasting C-peptide, postprandial C-peptide, and ΔC-peptide concentrations were lower in individuals with anemia. According to the grade of anemia, the average C-peptide concentrations differed significantly after adjusting for other covariates. In the multivariable model, the statistically significant relation between anemia and serum C-peptide concentrations remained after adjusting for confounders, including age, gender, family history of diabetes, body mass index, duration of diabetes, glycated Hb, free fatty acids, hypertension, and hyperlipidemia (fasting C-peptide concentration: ß = -0.057, P = .032; postprandial C-peptide concentration: ß = -0.098, P < .001; ΔC-peptide concentration: ß = -0.095, P < .001).Anemia was inversely associated with serum C-peptide concentrations in individuals with type 2 DM.


Assuntos
Anemia/sangue , Anemia/epidemiologia , Peptídeo C/sangue , Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/epidemiologia , Adulto , Idoso , Peptídeo C/metabolismo , Estudos Transversais , Jejum/metabolismo , Feminino , Hemoglobina A Glicada , Hemoglobinas/análise , Humanos , Masculino , Pessoa de Meia-Idade , Período Pós-Prandial/fisiologia
20.
Diabetes Care ; 41(10): 2220-2228, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-30082324

RESUMO

OBJECTIVE: Sedentary children have greater risk of developing abnormalities in glucose homeostasis. We investigated whether interrupting sedentary behavior (sitting) with very short periods of walking would improve glucose metabolism without affecting dietary intake in children with overweight or obesity. We hypothesized that interrupting sitting with short bouts of moderate-intensity walking would decrease insulin area under the curve (AUC) during an oral glucose tolerance test (OGTT) compared with uninterrupted sitting. RESEARCH DESIGN AND METHODS: Overweight/obese (BMI ≥85th percentile) children 7-11 years of age underwent two experimental conditions in random order: prolonged sitting (3 h of continuous sitting) and interrupted sitting (3 min of moderate-intensity walking at 80% of ventilatory threshold every 30 min for 3 h). Insulin, C-peptide, and glucose were measured every 30 min for 3 h during an OGTT. Each session was followed by a buffet meal. Primary outcomes were differences in OGTT hormones and substrates and in buffet meal intake by condition. RESULTS: Among 35 children with complete data, mixed-model results identified lower insulin and C-peptide in the interrupted condition (P = 0.007 and P = 0.029, respectively); the intervention reduced insulin AUC by 21% (P < 0.001) and C-peptide AUC 18% (P = 0.001) and improved estimated insulin sensitivity (P = 0.013). Neither buffet total energy intake (1,262 ± 480 vs. 1,260 ± 475 kcal; P = 0.89) nor macronutrient composition of the meal (P values >0.38) differed between conditions significantly. CONCLUSIONS: Interrupting sitting with brief moderate-intensity walking improved glucose metabolism without significantly increasing energy intake in children with overweight or obesity. Interrupting sedentary behavior may be a promising intervention strategy for reducing metabolic risk in such children.


Assuntos
Glicemia/metabolismo , Ingestão de Energia/fisiologia , Sobrepeso/metabolismo , Comportamento Sedentário , Caminhada/fisiologia , Glicemia/análise , Peptídeo C/sangue , Peptídeo C/metabolismo , Criança , Estudos Cross-Over , Feminino , Intolerância à Glucose/sangue , Intolerância à Glucose/metabolismo , Intolerância à Glucose/fisiopatologia , Teste de Tolerância a Glucose , Humanos , Insulina/sangue , Insulina/metabolismo , Resistência à Insulina/fisiologia , Masculino , Obesidade/sangue , Obesidade/metabolismo , Obesidade/fisiopatologia , Sobrepeso/sangue , Sobrepeso/fisiopatologia , Comportamento de Redução do Risco , Postura Sentada , Fatores de Tempo
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