Metabolism of vitamin D in the human choriocarcinoma cell line JEG-3.

Calcitriol is an antiproliferative prodifferentiating secosteroid that exerts a protective role for some kinds of cancer. Alterations in 25-hydroxyvitamin D-1alpha-hydroxylase (CYP27B1) activity have been found in some tumor cells, but there are no studies performed in human choriocarcinoma. In the present work, calcitriol production and CYP27B1 gene regulation were studied in the human choriocarcinoma cell line JEG-3, and compared with normal human syncytiotrophoblasts (hS) in culture. In JEG-3 cells, secretion of [(3)H]calcitriol was significantly less (P<0.001) than in hS (45+/-17fmol/mg protein versus 174+/-87fmol/mg protein, respectively; n=8). CYP27B1 mRNA was similar in both JEG-3 and hS cells; but the protein was detected only in hS extracts. In contrast to the hS, JEG-3 CYP27B1 gene expression was not regulated by calcitriol or by a cAMP analogue. Our results indicate that in JEG-3 cells calcitriol production is diminished due to CYP27B1 dysregulation and low protein content, and suggest that hyperproliferation could be a consequence of these alterations.

Effect of standard nicotinamide in the prevention of type 1 diabetes in first degree relatives of persons with type 1 diabetes.

BACKGROUND: Nicotinamide has been used with success to prevent type 1 diabetes in animal models and humans. This vitamin B3 derivative has attracting effects on beta-cell protection and regeneration. AIM/HYPOTHESIS: To evaluate the effect of standard nicotinamide administration on type 1 diabetes prevention in first degree relatives of persons with type 1 diabetes as well as on the concentrations of islet-cell-related autoantibodies, insulin secretion and peripheral sensitivity. SUBJECTS AND METHODS: A randomized double-blind placebo controlled intervention trial was conducted in 40 first degree relatives of type 1 diabetic patients. Persistence of ICA ( >or= 10 JDF units) was among inclusion criteria. Participants were randomly allocated oral standard nicotinamide (1.2 g/m2) or placebo for 5 years. Groups were also stratified by age. Islet associated antibodies, fasting blood glucose, fasting plasma insulin concentrations, OGTT, IVGTT and HLA-DR genotyping were performed in all participants. The main criterion to stop treatment was type 1 diabetes development as defined by WHO. RESULTS: Type 1 diabetes development frequencies were similar between the treatment groups. ICA frequencies at the end of the study, first phase insulin release, and insulin sensitivity did not differ between groups as well. None of the participants suffered from any adverse events described for nicotinamide. CONCLUSIONS: Type 1 diabetes prevention trial using standard nicotinamide is feasible but fails to prevent or delay the disease onset at the dose we used.

Pregestational Obesity-Induced Embryopathy.

INTRODUCTION: Several epidemiologic studies in humans have shown a relationship between pregestational obesity and congenital malformations in offsprings. However, there are no experimental evidence in animal models of obesity and pregnancy that reproduce the teratogenesis induced by this pathological condition. OBJECTIVE: To evaluate the effect of monosodium glutamate-induced obesity on embryonic development. METHODS: Female rats received subcutaneously (4 mg/g body weight) monosodium glutamate (MSG) solution or saline solution 0.9% (vehicle control) at days 2, 4, 6, 8, and 10 of life. At 90 days of age, all animals were mated, and on day 11 of pregnancy, the animals were killed. Biochemical variables (glucose, triglycerides, total cholesterol, and insulin) were determined in plasma of dams and embryo homogenates (DNA and protein content, advanced oxidation protein products). Embryos were evaluated for malformations, crown-rump length, and somite number. RESULTS: Obese rats presented higher triglyceride levels as compared to nonobese rats. Increased proportion of malformed embryos, decreased crown-rump length, somite number, DNA, and protein content were observed in offspring of obese rats. CONCLUSION: The model of obesity induced with MSG reproduces the maternal obesity-induced teratogenesis. The hypertriglyceridemia observed in MSG obese pregnant rats could be related to increased birth defect.

Expression and activity of 25-hydroxyvitamin D-1 alpha-hydroxylase are restricted in cultures of human syncytiotrophoblast cells from preeclamptic pregnancies.

The human placenta synthesizes 1,25-dihydroxyvitamin D(3) and expresses the vitamin D receptor. Because preeclampsia (PE) is associated with low circulating levels of maternal 1,25-dihydroxyvitamin D(3) and IGF-I, it is possible that alterations in calcium metabolism seen in PE could occur at the level of the fetoplacental unit. In this study, the patterns of gene expression and enzyme activity of 25-hydroxyvitamin D-1 alpha-hydroxylase (1 alpha-hydroxylase) and the abundance of IGF-I mRNA in placentas from normal (NT) and PE-complicated pregnancies were investigated. Cultured syncytiotrophoblast cells from preeclamptic placentas had only one tenth the activity of 1 alpha-hydroxylase and did not respond to IGF-I, when compared with NT cultures. Similarly, the levels of 1 alpha-hydroxylase mRNA in syncytiotrophoblast cells from PE placentas under basal and IGF-I-stimulated conditions were significantly reduced. In contrast, IGF-I mRNA levels were found to increase during the differentiation process, with no differences between NT and PE cultures. These results support the role of placenta as a contributor to the abnormalities observed in calcium metabolism in PE.

Slowly progressing type 1 diabetes: persistence of islet cell autoantibodies is related to glibenclamide treatment.

BACKGROUND: Several experimental studies in rats have demonstrated that sulfonylurea treatment increases autoantigen expression in B-cells. This phenomenon may be deleterious for the preservation of residual beta cell function in patients with slowly progressing type 1 diabetes or latent autoimmune diabetes of adult (LADA). AIM/HYPOTHESIS: The aim of the present study was to evaluate whether the exclusion of glibenclamide in the treatment of ICA positive type 2 diabetic patients may diminish or halt the humoral autoimmune response against B-cells as well as improve metabolic control and insulin secretion. SUBJECTS AND METHODS: Fourteen type 2 diabetic patients with pancreatic autoimmunity (ICA+ and GABA+) and treated with insulin and glibenclamide (duration of disease 2.0 +/- 2.2, range 0.1-7 years and age 53 +/- 12.5, range 36-75 years) were studied. Patients were randomly assigned to two treatment groups, Group 1: insulin monotherapy (n = 8, age 53 +/- 6.4 years) (Exclusion of glibenclamide) and, Group 2: insulin plus glibenclamide (n = 6, age 53.5 +/- 16.9) (Unmodified treatment). Both groups were investigated at the beginning of the study and after one year for the following parameters: ICA and anti-GAD65 antibodies, fasting glucose and fasting C-peptide. RESULTS: In group 1, six out of eight patients became ICA negative while all patients in group 2 remained ICA positive (p = 0.0097). Fasting glucose concentrations improved in group 1 (4.6 +/- 2.8) in relation to group 2 (11.5 +/- 5.5, p = 0.0023) after one year of treatment. No differences were found for anti-GAD antibodies and fasting C-Peptide between the groups. CONCLUSIONS: These data show that exclusion of glibenclamide in the treatment of ICA+ type 2 diabetic patients partially decreases specific autoimmunity against endocrine pancreatic cells and improves metabolic control. This may reflect decreased expression of B-cell autoantigens suggesting that insulin monotherapy is a better choice for the treatment of LADA.

Effect of Diamel in patients with metabolic syndrome: a randomized double-blind placebo-controlled study.

BACKGROUND: The aim of the present study was to determine whether the administration of Diamel, marketed as a food supplement by Catalysis Laboratories (Madrid, Spain) could improve any of the components of metabolic syndrome (MS), as well as insulin resistance and sensitivity. METHODS: In all, 100 patients with MS (19-70 years of age) who satisfied the World Health Organization criteria for MS were included in the study. Participants were randomly assigned to receive either oral Diamel or a placebo (while maintaining a diet appropriate to their weight and physical activity) at a dose of two capsules before each of the three main meals each day for 1 year. Anthropometric indices, blood pressure, fasting plasma glucose, lipid profile, insulin, creatinine, and uric acid (UA) were determined. Insulin resistance (IR) was assessed and three indirect indices were used to calculate insulin sensitivity (IS). RESULTS: Compared with placebo, Diamel improved fasting insulin concentrations, IS, and IR and reduced UA concentrations from 6 months until the end of treatment (P < 0.05 for all). In addition, after 12 months treatment with Diamel, significant changes from baseline were seen for mean fasting insulin (P < 0.05), UA (P < 0.05), IR (P < 0.001), and IS (P < 0.001), whereas no such changes were seen in the placebo-treated group. Improvements were noted in body mass index, IR, and IS in both groups. CONCLUSIONS: Long-term Diamel treatment, combined with lifestyle changes, was beneficial for IR and IS, and reduced serum UA levels in patients with MS.

First-degree relatives of persons with type 1 diabetes: insulin resistance and enterovirus infection are associated with different patterns of islet cell autoimmunity.

Type 1 diabetes (T1D) results from the interaction of genetic and environmental factors. Previous studies indicate an association between detection of Enterovirus (EV) genome in blood and the clinical onset of T1D. Insulin resistance can also represent a risk factor for progression to clinically overt T1D. This study aimed at evaluating whether there is association between both EV infection and insulin resistance with islet autoantibodies in first-degree relatives of persons with type 1 diabetes. We collected sera from 94 first-degree relatives with (32) or without (64) islet cell antibodies (ICA) from the Cuban T1D prediction program. Blood glucose and insulin concentrations were determined. Antibodies to GAD65 and IA-2 were determined by radioimmunoassay. Insulin resistance was estimated by the homeostasis model assessment (HOMA-IR). EV-RNA was detected in serum using a highly sensitive reverse transcriptase-polymerase chain reaction method. The occurrence of EV-RNA was higher in ICA-positive relatives than in ICA-negative ones [15.6% (5/32) vs. 1.6% (1/62), P = 0.016]. GAD65 autoantibodies were more frequent in subjects with insulin resistance [34.5% (10/29) vs. 13.9% (9/65), P = 0.028] as defined by the HOMA-IR value. GAD65 autoantibodies also positively correlated with HOMA-IR (r.bis = 0.28, P < 0.01). IA-2 autoantibodies did correlate neither with EV-RNA nor with insulin resistance. There was no association between the presence of EV-RNA and insulin resistance. Our data suggest that enterovirus infection and insulin resistance are two independent events associated with ICA and GAD65 autoantibodies, respectively. These observations support the multifactorial nature of T1D.

[Frequency and characteristics of metabolic syndrome and insulin resistance in the first-degree relatives of persons with type 1 diabetes]. / Frecuencia y características del síndrome metabólico y de la resistencia a la insulina en familiares de primer grado de personas con diabetes mellitus tipo 1.

AIM: To determine the frequency of metabolic syndrome (MS) and insulin resistance (IR) in first-degree relatives of type 1 diabetic patients (FDR1) and to study the relationship between these two disorders and some clinical, biochemical and immunological characteristics. SUBJECTS AND METHODS: We studied 289 persons, of which 193 were children/adolescents and 96 were adults. Weight, height, waist and hip circumference, blood pressure, blood glucose, insulin, cholesterol, triglycerides, high-density lipoprotein-cholesterol, glutamic acid decarboxylase autoantibodies (GADA) and tyrosine phosphatase autoantibodies were determined. IR was assessed through the insulin resistance index (HOMA-IR). The criteria of the World Health Organization for adults and the Cuban consensus for children and adolescents were used to define MS. RESULTS: The prevalence of MS in child and adolescent FDR1 was 5.7% (11/193) while IR was found in 24.9% (48/193). For adult FDR1, the frequency of MS was 6.2% (6/96) and that of IR was 14.6% (14/96). Interestingly, an association was found between IR and MS in adults but not in children and adolescents. IR was more frequent in children and adolescents than in adults (p<0.05). The presence of GADA was associated with IR but not with MS (p<0.05). CONCLUSIONS: The frequency of MS in child and adolescent FDR1 was similar to that found in the general population according to studies using similar definitions of MS. In contrast, the frequency of MS in adults was lower than that reported in Cuba for the first-degree relatives of patients with type 2 diabetes. IR was not only associated with MS in first-degree relatives. The association of IR with the presence of GADA may reflect the fact that beta cell hyperactivity increases autoantigen expression.

Islet cell related antibodies and type 1 diabetes associated with echovirus 30 epidemic: a case report.

Type 1 diabetes associated genes account for less than 50% of disease susceptibility. Human enteroviruses have been implicated as environmental factors that might trigger and/or accelerate this autoimmune disorder. We now report of a 12-year-old girl that developed pancreatic autoimmunity and type 1 diabetes after enteroviral infection. Diabetes-associated autoimmunity was evaluated by measurement of several islet cell related autoantibodies. Neutralizing antibodies to different enteroviruses were determined in the case and eight children suffering from aseptic meningitis during a large scale epidemic. Several types of diabetes-associated antibodies were detected post-infection in the adolescent with newly diagnosed type 1 diabetes, including islet cell antibodies (ICA) and tyrosine phosphatase antibodies (IA2A). ICA but not IA2A appeared in the non-diabetic enterovirus-infected subjects. Based on virological studies, type 1 diabetes pathogenesis process could have been triggered by echovirus 30 infections. This study provides the first evidence of an association between echovirus 30 infection with the presence of pancreatic autoimmunity and type 1 diabetes. Our data suggest that echovirus 30 Cuban strain could be considered a potentially diabetogenic enteroviral variant.

Utilizaciòn de un método rápido para la separación de la hormona libre y unida en el radioinmunoensayo de insulina / Use of a rapid method for separating the bound and unbound hormone in insulin radioimmunoassay

Se desarrolló un método para acelerar la reacción del segundo anticuerpo (Ac) en el radioinmunoensayo (RIA) de insulina (ins) mediante el uso de polietilenglicol (PEG). El método permite acortar el tiempo de duración del ensayo en un día, lo cual representa una ventaja sobre el RIA habitual, ya que al aumentar el número de corridas semanales aumenta la productividad de los técnicos y constituye un ahorro de salario. Al comparar este método con el del segundo anticuerpo, se comprobó que no existe diferencia entre los resultados de ambos métodos y que hay una buena correlación entre los mismos. lo que brinda perspectiva para poder optimizar dicho método con vistas a su aplicaciòn en la asistencia y en la investigación

Efectos de la tibolona sobre el metabolismo de lípidos, glucosa y secreción de insulina en mujeres posmenopáusicas / Effects of tibolone on lipids glucose metabolism and insuline secretion in postmenopausal women

La tibolona es un esteroide sintético con propiedades progestacional, androgénica y estrogénica que ha demostrado aliviar los síntomas climatéricos, prevenir la osteoporosis, sin impacto sobre el endometrio y el volumen de los miomas uterinos asintomáticos. Además, se ha demostrado que induce una reducción significativa en los niveles séricos de colesterol y triglicéridos. Sin embargo, los estudios sobre sus efectos en el metabolismo de los carbohidratos son escasos y contradictorios. El objetivo de este estudio fue determinar los efectos de la tibolona sobre la curva de tolerancia a la glucosa y la secreción de insulina. Se incluyeron 10 pacientes posmenopáusicas sanas que recibieron una dosis de 2.5 mg de tibolona por VO durante tres meses. Al inicio y al final de estudio se realizaron curvas de tolerancia a la glucosa, cuantificación de insulina en ayuno y una hora después de una carga de 100 g de glucosa por VO y perfil de lípidos (colesterol total, triglicéridos, HDL, LDL, Apo-LpA, Apo-LpB). Nuestros resultados demostraron una reducción significativa en los niveles de insulina en ayuno, colesterol y triglicéridos después de tres meses de tratamiento con tibolona. La curva de tolerancia a la glucosa no se modificó. Este estudio sugiere que la tibolona reduce la presencia de marcadores metabólicos de riesgo cardiovascular diferentes a las fracciones de lipoproteínas

Método inmunoenzimático (ELISA) para la detección de anticuerpos anti-insulina / Enzyme immunoassay (ELISA) for detecting anti-insulin antibodies

Se describen los procedimientos empleados y los resultados obtenidos en la purificación del inmunógeno, anticuerpo específico y producción de conjugados, los cuales contaron con la calidad requerida. Se presentan los resultados del montaje y validación preliminar de un método inmunoenzimático para determinar anticuerpos anti-insulina en suero humano. Se evaluó la aplicación del método en la detección de anticuerpos en 130 muestras de sujetos normales y 55 de pacientes diabéticos y sus familiares, dada la importancia de dicha determinación para el mejor control y tratamiento de los diabéticos insulinodependientes. así como en la predicción del inicio clínico de la diabetes

Detección de anticuerpos antiinsulina por un método inmunoenzimático (MicroELISA) / Detection of anti-insuline antibodies by inmunoenzymatic method (microELISA)

Se realizò el montaje de un método inmunoenzimático (ELISA) para la detección de anticuerpos capaces de reconocer la molécula de insulina y se aplicó a un grupo de 130 sujetos normales; se escogió el valor límite de negatividad para el ensayo y se aplicó a la población estudiada de diabéticos. Los coeficientes de variación obtenidos se hallan dentro del rango de valores normales para este procedimiento. No se observó correspondencia total entre los resultados de las muestras evaluadas con este método y el isotópico convencional empleado en el Instituto Nacional de Endocrinología. Se llegó a la conclusión de que estos 2 métodos detectan diferentes tipos de anticuerpos antiinsulina