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1.
Nature ; 625(7996): 760-767, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-38092039

RESUMEN

GDF15, a hormone acting on the brainstem, has been implicated in the nausea and vomiting of pregnancy, including its most severe form, hyperemesis gravidarum (HG), but a full mechanistic understanding is lacking1-4. Here we report that fetal production of GDF15 and maternal sensitivity to it both contribute substantially to the risk of HG. We confirmed that higher GDF15 levels in maternal blood are associated with vomiting in pregnancy and HG. Using mass spectrometry to detect a naturally labelled GDF15 variant, we demonstrate that the vast majority of GDF15 in the maternal plasma is derived from the feto-placental unit. By studying carriers of rare and common genetic variants, we found that low levels of GDF15 in the non-pregnant state increase the risk of developing HG. Conversely, women with ß-thalassaemia, a condition in which GDF15 levels are chronically high5, report very low levels of nausea and vomiting of pregnancy. In mice, the acute food intake response to a bolus of GDF15 is influenced bi-directionally by prior levels of circulating GDF15 in a manner suggesting that this system is susceptible to desensitization. Our findings support a putative causal role for fetally derived GDF15 in the nausea and vomiting of human pregnancy, with maternal sensitivity, at least partly determined by prepregnancy exposure to the hormone, being a major influence on its severity. They also suggest mechanism-based approaches to the treatment and prevention of HG.


Asunto(s)
Factor 15 de Diferenciación de Crecimiento , Hiperemesis Gravídica , Náusea , Vómitos , Animales , Femenino , Humanos , Ratones , Embarazo , Talasemia beta/sangre , Talasemia beta/metabolismo , Feto/metabolismo , Factor 15 de Diferenciación de Crecimiento/sangre , Factor 15 de Diferenciación de Crecimiento/metabolismo , Hormonas/sangre , Hormonas/metabolismo , Hiperemesis Gravídica/complicaciones , Hiperemesis Gravídica/metabolismo , Hiperemesis Gravídica/prevención & control , Hiperemesis Gravídica/terapia , Náusea/sangre , Náusea/complicaciones , Náusea/metabolismo , Placenta/metabolismo , Vómitos/sangre , Vómitos/complicaciones , Vómitos/metabolismo
2.
Ultrasound Obstet Gynecol ; 59(1): 40-48, 2022 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-34254386

RESUMEN

OBJECTIVES: To validate prospectively transvaginal ultrasound assessment of the lower uterine segment (LUS) scar at the time of first-trimester screening in women with previous Cesarean section (CS) and to determine its feasibility and accuracy in stratifying women according to the risk for placenta accreta spectrum (PAS) disorder. METHODS: Women with a history of CS were recruited between 11 + 0 and 13 + 6 weeks' gestation and underwent LUS scar assessment using transvaginal ultrasound. A standardized midsagittal plane, which included the cervicoisthmic canal (CIC), the uterine scar and the placental site, was obtained. The scar was described in terms of its size (narrow or dehiscent) and its location in relation to the CIC (within or above), with each LUS scar classified into one of four groups based on these features. Placental location was assessed and classified as high- or low-lying. Women were stratified according to the risk of PAS, based on the relationship between the scar location and placental site. Women were considered high risk when the scar was above the CIC and the placenta was low-lying (i.e. when the placenta was overlying an exposed scar) and low risk when the scar was within the CIC and/or the placenta was high. High-risk patients were followed up at 20 weeks and 28-30 weeks for the development of PAS. Maternal demographics, detailed obstetric history and obstetric outcome were collected. RESULTS: First-trimester transvaginal ultrasound was offered to 535 women with prior CS during the study period. A LUS scar was visualized in 79.9% (401/502) of those who agreed to undergo the examination. At this scan, the LUS scar was above the CIC in 9.0% (36/401) of women, but only 5.7% (23/401) additionally had a low-lying placenta overlying the scar. Of these 23 high-risk women, two were found to have PAS on the mid-trimester screening scan and one was noted to have placental adherence during evacuation following mid-trimester termination of pregnancy. On the first-trimester scan, 94.3% (378/401) of women were at low risk of PAS. This screening protocol yielded a positive likelihood ratio of 21.33 (95% CI, 13.02-34.96), sensitivity of 100% (95% CI, 29.24-100%), specificity of 95.31% (95% CI, 92.39-97.35%), positive predictive value of 16.7% (95% CI, 5.8-39.2%) and negative predictive value of 100% (95% CI, 98.4-100%). On multivariable regression analysis performed to identify confounding variables associated with a LUS scar above the CIC, only maternal body mass index ≥ 30 kg/m2 was significant (odds ratio (OR), 2.42 (95% CI, 1.04-5.39); P = 0.03). Although there was a trend towards an increased risk of a LUS scar above the CIC in women with prior elective prelabor CS (OR, 1.72 (95% CI, 0.80-3.68)), this association did not reach statistical significance. CONCLUSIONS: Routine transvaginal ultrasound assessment of the location of the LUS scar and placenta at the time of first-trimester screening between 11 + 0 and 13 + 6 weeks' gestation in women with prior CS is a feasible and effective tool to identify those at risk of subsequent development of PAS disorder. A finding of placental implantation over an exposed LUS scar seems to be cardinal in predicting the risk of PAS disorder in women with prior CS, with an excellent negative predictive value. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.


Asunto(s)
Cesárea/efectos adversos , Cicatriz/diagnóstico por imagen , Placenta Accreta/diagnóstico por imagen , Medición de Riesgo/métodos , Ultrasonografía Prenatal/métodos , Adulto , Cicatriz/complicaciones , Estudios de Factibilidad , Femenino , Edad Gestacional , Humanos , Placenta/diagnóstico por imagen , Placenta Accreta/etiología , Embarazo , Primer Trimestre del Embarazo , Estudios Prospectivos , Útero/diagnóstico por imagen , Útero/patología , Útero/cirugía
3.
Mol Metab ; 43: 101127, 2021 01.
Artículo en Inglés | MEDLINE | ID: mdl-33242659

RESUMEN

OBJECTIVE: More than 300 genetic variants have been robustly associated with measures of human adiposity. Highly penetrant mutations causing human obesity do so largely by disrupting satiety pathways in the brain and increasing food intake. Most of the common obesity-predisposing variants are in, or near, genes expressed highly in the brain, but little is known of their function. Exploring the biology of these genes at scale in mammalian systems is challenging. We sought to establish and validate the use of a multicomponent screen for feeding behaviour phenotypes, taking advantage of the tractable model organism Drosophila melanogaster. METHODS: We validated a screen for feeding behaviour in Drosophila by comparing results after disrupting the expression of centrally expressed genes that influence energy balance in flies to those of 10 control genes. We then used this screen to explore the effects of disrupted expression of genes either a) implicated in energy homeostasis through human genome-wide association studies (GWAS) or b) expressed and nutritionally responsive in specific populations of hypothalamic neurons with a known role in feeding/fasting. RESULTS: Using data from the validation study to classify responses, we studied 53 Drosophila orthologues of genes implicated by human GWAS in body mass index and found that 15 significantly influenced feeding behaviour or energy homeostasis in the Drosophila screen. We then studied 50 Drosophila homologues of 47 murine genes reciprocally nutritionally regulated in POMC and agouti-related peptide neurons. Seven of these 50 genes were found by our screen to influence feeding behaviour in flies. CONCLUSION: We demonstrated the utility of Drosophila as a tractable model organism in a high-throughput genetic screen for food intake phenotypes. This simple, cost-efficient strategy is ideal for high-throughput interrogation of genes implicated in feeding behaviour and obesity in mammals and will facilitate the process of reaching a functional understanding of obesity pathogenesis.


Asunto(s)
Apetito/genética , Apetito/fisiología , Conducta Alimentaria/fisiología , Animales , Índice de Masa Corporal , Encéfalo , Drosophila melanogaster/genética , Metabolismo Energético , Estudio de Asociación del Genoma Completo , Genotipo , Homeostasis , Hipotálamo/metabolismo , Neuronas/metabolismo , Estado Nutricional , Obesidad/metabolismo , Fenotipo
4.
Int J Obes (Lond) ; 37(5): 744-7, 2013 May.
Artículo en Inglés | MEDLINE | ID: mdl-22614055

RESUMEN

Genome-wide association studies have revealed that single nucleotide polymorphisms in fat mass and obesity-associated transcript (FTO) are robustly associated with body mass index and obesity. Expression of Fto in the hypothalamic arcuate nucleus is bidirectionally regulated as a function of nutritional status; decreasing following a 48-h fast and increasing after 10-week exposure to a high-fat diet. Here, we utilize an in vitro approach to determine which nutrients could regulate FTO levels at a cellular level. Using mouse and human cell lines, we find that FTO levels are not influenced by serum starvation. We demonstrate, however, that both glucose and total amino-acid deprivation regulates FTO expression. In particular, we have found that FTO mRNA and protein levels are dramatically downregulated by total amino-acid deprivation in mouse hypothalamic N46 cells, mouse embryonic fibroblasts and in human HEK293 cells. The drop rate of Fto mRNA is faster than its rate of natural degradation, pointing to regulation at the transcriptional level, which is reversible upon amino-acid replacement. Strikingly, this downregulation was seen only with essential amino-acid deficiency and not nonessential amino acids. These data suggest that FTO might have a role in the sensing of essential amino-acid availability.


Asunto(s)
Aminoácidos Esenciales/metabolismo , Núcleo Arqueado del Hipotálamo/metabolismo , Glucosa/metabolismo , Oxigenasas de Función Mixta/metabolismo , Obesidad/metabolismo , Oxo-Ácido-Liasas/metabolismo , Proteínas/metabolismo , Dioxigenasa FTO Dependiente de Alfa-Cetoglutarato , Animales , Western Blotting , Línea Celular , Dieta Alta en Grasa , Regulación hacia Abajo , Regulación de la Expresión Génica , Estudio de Asociación del Genoma Completo , Células HEK293 , Humanos , Ratones , Obesidad/genética , Obesidad/fisiopatología , Polimorfismo de Nucleótido Simple , ARN Mensajero/metabolismo , Factores de Tiempo
5.
Diabetes Obes Metab ; 14 Suppl 3: 57-67, 2012 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-22928565

RESUMEN

ß-Cell dysfunction is a critical component in the development of type 2 diabetes. Whilst both genetic and environmental factors contribute to the development of the disease, relatively little is known about the molecular network that is responsible for diet-induced functional changes in pancreatic ß-cells. Recent genome-wide association studies for diabetes-related traits have generated a large number of candidate genes that constitute possible links between dietary factors and the genetic susceptibility for ß-cell failure. Here, we summarize recent approaches for identifying nutritionally regulated transcripts in islets on a genome-wide scale. Polygenic mouse models for type 2 diabetes have been instrumental for investigating the mechanism of diet-induced ß-cell dysfunction. Enhanced oxidative metabolism, triggered by a combination of dietary carbohydrates and fat, appears to play a critical role in the pathophysiology of diet-induced impairment of islets. More systematic studies of gene-diet interactions in ß-cells of rodent models in combination with genetic profiling might reveal the regulatory circuits fundamental for the understanding of diet-induced impairments of ß-cell function in humans.


Asunto(s)
Diabetes Mellitus Tipo 2/metabolismo , Dieta , Células Secretoras de Insulina/metabolismo , Insulina/metabolismo , Polimorfismo de Nucleótido Simple , Animales , Diabetes Mellitus Tipo 2/dietoterapia , Diabetes Mellitus Tipo 2/genética , Epigénesis Genética , Perfilación de la Expresión Génica , Predisposición Genética a la Enfermedad , Estudio de Asociación del Genoma Completo , Prueba de Tolerancia a la Glucosa , Humanos , Insulina/genética , Ratones , Ratones Endogámicos C57BL , Ratones Obesos , Herencia Multifactorial
6.
Singapore Med J ; 52(6): e118-23, 2011 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-21731981

RESUMEN

Sacrococcygeal teratoma (SCT) is a congenital tumour that can be diagnosed by ultrasonography (USG). We present our experience with the management of two cases of SCT in our institution between 2008 and 2009. In the first case, SCT was diagnosed at 17 weeks' gestation. The patient was followed up with fortnightly USG to monitor the tumour size, foetal growth and signs of foetal hydrops. The patient delivered a baby girl by Caesarean section at 37 weeks, with good Apgar scores. The neonate underwent an uneventful resection of SCT on Day 1 of life. In the second case, SCT was diagnosed at 20 weeks during screening. In view of foetal hydrops and anaemia, the patient underwent three in utero foetal blood transfusions. A baby boy was delivered by Caesarean section at 28 weeks. There was a large friable SCT with massive haemorrhage. Despite maximal resuscitative efforts, the neonate died 30 minutes after birth.


Asunto(s)
Enfermedades Fetales/patología , Región Sacrococcígea/patología , Teratoma/diagnóstico por imagen , Teratoma/patología , Adulto , Resultado Fatal , Femenino , Enfermedades Fetales/diagnóstico , Edad Gestacional , Humanos , Recién Nacido , Masculino , Embarazo , Resultado del Embarazo , Teratoma/diagnóstico , Resultado del Tratamiento , Ultrasonografía Prenatal
7.
Ultrasound Obstet Gynecol ; 38(5): 533-7, 2011 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-21557370

RESUMEN

OBJECTIVE: To evaluate the degree of agreement in first-trimester nasal bone assessment in a group of sonographers before and after training, using a semi-quantitative scoring system. METHODS: Four sonographers who routinely perform first-trimester screening were first shown 46 images from both normal and trisomy 21 pregnancies. For each image, they were asked to score from 0 (disagree) to 3 (agree) on five different criteria that were deemed important in nasal-bone assessment, including image size, plane and visibility of nasal bone. A training program was then conducted, and a repeat exercise was carried out using the same 46 images. Finally, in a third exercise, images from 42 patients were presented, some having more than one image. The sonographers were required to give one overall nasal-bone score for each patient. In each exercise interobserver agreement was evaluated by intraclass correlation coefficient (ICC). RESULTS: Before training, the sonographers agreed reasonably well on the five proposed criteria (ICC, 0.752), with some disagreement on their perceived image quality. The training program further improved the agreement (ICC, 0.790), particularly on whether the nasal bone was the biggest and brightest echogenic component. Agreement was excellent when they were asked to give one overall score on the nasal bone based on multiple images from one patient (ICC, 0.929). CONCLUSION: The proposed scoring system can be used to improve consistency and reliability in first-trimester nasal-bone assessment.


Asunto(s)
Síndrome de Down/diagnóstico por imagen , Hueso Nasal/diagnóstico por imagen , Primer Trimestre del Embarazo , Ultrasonografía Prenatal/métodos , Síndrome de Down/embriología , Femenino , Humanos , Hueso Nasal/embriología , Variaciones Dependientes del Observador , Embarazo , Garantía de la Calidad de Atención de Salud , Reproducibilidad de los Resultados , Encuestas y Cuestionarios
8.
J Neuroendocrinol ; 23(2): 177-85, 2011 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-21070396

RESUMEN

We have addressed the question of how different rodent species cope with the life-threatening homeostatic challenge of dehydration at the level of transcriptome modulation in the supraoptic nucleus (SON), a specialised hypothalamic neurosecretory apparatus responsible for the production of the antidiuretic peptide hormone arginine vasopressin (AVP). AVP maintains water balance by promoting water conservation at the level of the kidney. Dehydration evokes a massive increase in the regulated release of AVP from SON axon terminals located in the posterior pituitary, and this is accompanied by a plethora of changes in the morphology, electrophysiological properties, biosynthetic and secretory activity of this structure. Microarray analysis was used to generate a definitive catalogue of the genes expressed in the mouse SON, and to describe how the gene expression profile changes in response to dehydration. Comparison of the genes differentially expressed in the mouse SON as a consequence of dehydration with those of the rat has revealed many similarities, pointing to common processes underlying the function-related plasticity in this nucleus. In addition, we have identified many genes that are differentially expressed in a species-specific manner. However, in many cases, we have found that the hyperosmotic cue can induce species-specific alterations in the expression of different genes in the same pathway. The same functional end can be served by different means, via differential modulation, in different species, of different molecules in the same pathway. We suggest that pathways, rather than specific genes, should be the focus of integrative physiological studies based on transcriptome data.


Asunto(s)
Deshidratación/fisiopatología , Perfilación de la Expresión Génica/métodos , Regulación de la Expresión Génica/fisiología , Ratones , Ratas , Transducción de Señal/fisiología , Núcleo Supraóptico/metabolismo , Animales , Deshidratación/metabolismo , Masculino , Ratones Endogámicos C57BL , Transducción de Señal/genética , Especificidad de la Especie
9.
J Neuroendocrinol ; 22(8): 915-25, 2010 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-20553370

RESUMEN

Leptin plays a major role in coordinating the integrated response of the brain to changes in nutritional state. Leptin receptor expressing neurones within the arcuate nucleus (ARC) of the hypothalamus sense circulating leptin and densely innervate other regions of the hypothalamus, including the paraventricular nucleus (PVN). In the ARC, leptin is known to alter the expression of genes with important roles in the control of energy balance, and the aim of the present study was to obtain a more comprehensive picture of the action of leptin in these nuclei. Mice were ad libitum fed, or fasted for 48 h when receiving either sham or i.p. leptin treatment. We used laser capture microdissection and microarrays to identify leptin-regulated transcripts within the ARC. Expression of 639 genes are increased and 452 decreased within the fasted ARC. Leptin regulates 15% and 20% of these genes, respectively. In addition to expected changes in Pomc, Agrp, Npy and Cart, pathway analysis indicated that leptin regulated other genes concerned with energy homeostasis and endocrine function. As previously reported for the PVN, leptin also altered the expression of genes involved in nervous system development and synaptic function. However, aside from a small number of such genes (e.g. Gap43), leptin influenced the expression of different sets of neuronal developmental genes in the ARC and PVN. In conclusion, the present study identifies a set of genes that are regulated, at least in part, by leptin in the ARC, highlighting these as candidates for possible roles in leptin action and resistance.


Asunto(s)
Núcleo Arqueado del Hipotálamo/fisiología , Ayuno/fisiología , Perfilación de la Expresión Génica , Regulación de la Expresión Génica , Leptina/metabolismo , Animales , Masculino , Ratones , Análisis por Micromatrices , Datos de Secuencia Molecular
10.
J Neuroendocrinol ; 22(3): 181-7, 2010 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-20041982

RESUMEN

Growing evidence suggests the tachykinin neurokinin B (NKB) may modulate gonadotrophin secretion and play a role in sex-steroid feedback within the reproductive axis. NKB signalling has recently been identified as being necessary for normal human reproductive function, although the precise mechanisms underpinning this role remain to be established. We have used rodents to explore further the role of NKB within the reproductive axis. In particular, we have studied its interactions with kisspeptin, a neuropeptide essential for reproductive function in rodent and human with close anatomical links to NKB within the hypothalamus. Intraperitoneal administration of NKB (50 nmol) to male mice had no effect on circulating luteinsing hormone (LH) levels and, although i.p. kisspeptin (15 nmol) increased LH five-fold, co-administration of NKB and kisspeptin was indistinguishable from kisspeptin alone. Intracerebroventricular administration of NKB (10 nmol) to male mice also had no effect on LH levels, with 1 nmol kisspeptin i.c.v. significantly increasing LH compared to control (0.37 +/- 0.18 versus 5.11 +/- 0.28 ng/ml, respectively). Interestingly, i.c.v. co-administration of NKB and kisspeptin caused a significant increase in LH concentrations compared to kisspeptin alone (8.96 +/- 1.82 versus 5.11 +/- 0.28 ng/ml respectively). We used hypothalamic explants from rats to assess the effect of NKB on gonadotrpohin-releasing hormone (GnRH) secretion ex vivo. Doses of NKB up to 1000 nm failed to stimulate GnRH secretion, whereas 100 nm kisspeptin robustly increased GnRH secretion. Of note, co-administration of NKB with kisspeptin abrogated the effect of kisspeptin, producing no GnRH release above basal state. Finally, we analysed the expression of Tac2/Tacr3 (genes encoding NKB and NK3R, respectively) within the arcuate nucleus in different nutritional states. After a 48-h fast, the expression of both Tac2 and Tacr3 showed a significant increase, in contrast to levels of Kiss1 and Kiss1r mRNA, which remained unchanged. In male rodent models, NKB and kisspeptin have different effects upon gonadotrophin release and appear to interact in a complex manner.


Asunto(s)
Hormona Luteinizante/metabolismo , Neuroquinina B/farmacología , Proteínas/farmacología , Animales , Núcleo Arqueado del Hipotálamo/efectos de los fármacos , Núcleo Arqueado del Hipotálamo/metabolismo , Ayuno/metabolismo , Hormona Liberadora de Gonadotropina/sangre , Hormona Liberadora de Gonadotropina/metabolismo , Kisspeptinas , Hormona Luteinizante/sangre , Masculino , Ratones , Ratones Endogámicos C57BL , Neuroquinina B/administración & dosificación , Precursores de Proteínas/biosíntesis , Proteínas/administración & dosificación , Ratas , Ratas Wistar , Receptores de Taquicininas/biosíntesis , Taquicininas/biosíntesis
11.
Int J Obes (Lond) ; 34(1): 190-4, 2010 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-19844213

RESUMEN

CONTEXT: The PNPLA3 I148M variant (rs738409) is robustly associated with hepatic steatosis. Intriguingly, initial findings in cohorts with a mean body mass index (BMI) of 30 kg m(-2) also suggested that it is associated with elevated liver enzymes but not with insulin resistance and dyslipidaemia. OBJECTIVE: To determine whether the PNPLA3 variant alters the susceptibility of morbidly obese subjects to develop liver injury and metabolic sequelae. PARTICIPANTS AND METHODS: The study was carried out in 678 obese Italians (mean BMI = 41 kg m(-2)) who were genotyped for the I148M variant. All participants provided fasting blood samples and then underwent oral glucose tolerance tests. MAIN OUTCOME MEASURES: Indices of liver injury (alanine transaminase (ALT), aspartate transaminase (AST)), glucose tolerance and insulin resistance were measured. RESULTS: Markers of hepatic injury such as ALT and AST were significantly higher in carriers of the 148M allele (P = 2.2 x 10(-5) and 0.001, respectively). In all, 50% of 148M risk allele homozygotes had pathological levels of ALT (>40 U l(-1)) compared with 25% of 148I allele homozygotes (P = 0.005). Glucose tolerance and insulin sensitivity were similar in all three genotypes. CONCLUSION: Obese Southern Europeans carrying the 148M allele have increased indices of liver damage uncoupled from proxy measures of insulin resistance.


Asunto(s)
Hígado Graso/enzimología , Variación Genética/genética , Resistencia a la Insulina/genética , Lipasa/genética , Proteínas de la Membrana/genética , Obesidad Mórbida/genética , Adulto , Alanina Transaminasa/sangre , Aspartato Aminotransferasas/sangre , Biomarcadores/sangre , Índice de Masa Corporal , Hígado Graso/sangre , Femenino , Predisposición Genética a la Enfermedad/genética , Genotipo , Prueba de Tolerancia a la Glucosa , Humanos , Italia , Lipasa/metabolismo , Masculino , Proteínas de la Membrana/metabolismo , Obesidad Mórbida/sangre , Obesidad Mórbida/etnología
12.
Diabetologia ; 53(2): 309-20, 2010 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-19902174

RESUMEN

AIMS/HYPOTHESIS: Numerous new genes have recently been identified in genome-wide association studies for type 2 diabetes. Most are highly expressed in beta cells and presumably play important roles in their function. However, these genes account for only a small proportion of total risk and there are likely to be additional candidate genes not detected by current methodology. We therefore investigated islets from the polygenic New Zealand mouse (NZL) model of diet-induced beta cell dysfunction to identify novel genes and pathways that may play a role in the pathogenesis of diabetes. METHODS: NZL mice were fed a diabetogenic high-fat diet (HF) or a diabetes-protective carbohydrate-free HF diet (CHF). Pancreatic islets were isolated by laser capture microdissection (LCM) and subjected to genome-wide transcriptome analyses. RESULTS: In the prediabetic state, 2,109 islet transcripts were differentially regulated (>1.5-fold) between HF and CHF diets. Of the genes identified, 39 (e.g. Cacna1d, Chd2, Clip2, Igf2bp2, Dach1, Tspan8) correlated with data from the Diabetes Genetics Initiative and Wellcome Trust Case Control Consortium genome-wide scans for type 2 diabetes, thus validating our approach. HF diet induced early changes in gene expression associated with increased cell-cycle progression, proliferation and differentiation of islet cells, and oxidative stress (e.g. Cdkn1b, Tmem27, Pax6, Cat, Prdx4 and Txnip). In addition, pathway analysis identified oxidative phosphorylation as the predominant gene-set that was significantly upregulated in response to the diabetogenic HF diet. CONCLUSIONS/INTERPRETATION: We demonstrated that LCM of pancreatic islet cells in combination with transcriptional profiling can be successfully used to identify novel candidate genes for diabetes. Our data strongly implicate glucose-induced oxidative stress in disease progression.


Asunto(s)
Dieta para Diabéticos , Dieta , Regulación de la Expresión Génica , Islotes Pancreáticos/fisiología , Síndrome Metabólico/genética , Animales , Ciclo Celular/genética , Ciclo Celular/fisiología , División Celular/fisiología , Amplificación de Genes , Perfilación de la Expresión Génica , Hiperglucemia/genética , Hiperglucemia/prevención & control , Islotes Pancreáticos/citología , Cinética , Masculino , Síndrome Metabólico/veterinaria , Ratones , Herencia Multifactorial , Reacción en Cadena de la Polimerasa , ARN/genética , ARN/aislamiento & purificación , Transcripción Genética
13.
Singapore Med J ; 50(6): 587-90, 2009 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-19551311

RESUMEN

INTRODUCTION: Turner syndrome is the most common sex chromosomal abnormality in female foetuses, and is associated with a high proportion of cardiac anomalies. The aim of this study was to look at the incidence, demographical data and epidemiological pattern of Turner syndrome in Singapore from 1999 to 2004 and to examine the birth defects associated with this condition, specifically with reference to cardiac defects. METHODS: Data on Turner syndrome cases born in 1999-2004 were retrieved from the National Birth Defects Registry (NBDR) and analysed. Data on congenital cardiac defect cases notified to the NBDR in the same time period were also retrieved and compared with the Turner syndrome cases. RESULTS: There were a total of 101 cases of Turner syndrome in the six-year period from 1999-2004, yielding an overall incidence of 0.85 per 1,000 female live births, or one in 1,180 female live births. The incidence was lowest among Indians (0.38 per 1,000) compared to Malays (0.72 per 1,000) and Chinese (0.90 per 1,000). 75 cases (74.3 percent) had the 45,X karyotype, while the other 26 cases (25.7 percent) were mosaics. The mean maternal age for 45,X was lower (32.2 years, range 22-42) compared to mosaics (34.5 years, range 27-40). 19.8 percent (20/101) were live births, 38.6 percent (39/101) were terminated pregnancies and 41.6 percent (42/101) were spontaneous miscarriages. 13.9 percent of Turner syndrome babies had cardiac defects compared to 1.2 percent in the general population (p-value is less than 0.0001). Major cardiac defects found among Turner syndrome babies compared to the general population included the coarctation of the aorta (5.9 percent compared to 0.03 percent, p-value is less than 0.0001), atrial septal defects (3.0 percent compared to 0.6 percent, p-value is 0.006), a hypoplastic left heart (2.0 percent compared to 0.05 percent, p-value is less than 0.0001), aortic hypoplasia (3.0 percent compared to 0.01 percent, p-value is less than 0.0001) and dextrocardia (1.0 percent compared to 0.02 percent, p-value is 0.0002). CONCLUSION: Cardiac defects, particularly left-sided ones, are significantly more common among Turner syndrome foetuses. The true incidence of this syndrome is likely to be higher than that quoted in this study, and can only be solved when a complete screening of an entire population has been performed.


Asunto(s)
Síndrome de Turner/epidemiología , Síndrome de Turner/genética , Adulto , Aberraciones Cromosómicas , Anomalías Congénitas/genética , Femenino , Cardiopatías Congénitas/complicaciones , Cardiopatías Congénitas/genética , Humanos , Incidencia , Recién Nacido , Cariotipificación , Edad Materna , Mosaicismo , Singapur , Síndrome de Turner/complicaciones
14.
Singapore Med J ; 49(9): 710-4, 2008 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-18830546

RESUMEN

INTRODUCTION: Cleft deformities, though non-lethal, receive much attention from parents and doctors alike because of their obvious physical disfigurement, social stigma and associated feeding and vocal articulation problems. There is also an association with chromosomal defects for certain cleft deformities. The aim of this study is to examine the incidence, demographic data and epidemiological trend of this condition over a ten-year period, and to compare our data with other local studies, as well as to examine the chromosomal defects associated with this condition. METHODS: Data of cleft deformity cases born during the period 1993-2002 was retrieved from the National Birth Defects Registry and analysed. RESULTS: There were a total of 859 cases of cleft deformities in the ten-year period 1993-2002, giving an overall incidence of 1.87 per 1,000 live births, with an increasing trend noted. Incidence was highest among the Chinese and lowest among the Indians. There were more males with cleft deformities compared with females. The risk of aneuploidy rose by about ten-fold in syndromic cleft cases, compared to non-syndromic cleft cases. There were two cases of Trisomy 21 in the non-syndromic cleft lip and palate group, giving an incidence of 1:133. CONCLUSION: The race-specific and gender-specific differences in cleft incidence suggest genetic and environmental factors which warrant further studies. The increased risk of aneuploidy among syndromic clefts, as well as the finding of Trisomy 21 in non-syndromic cleft lip and palate cases suggest a need for karyotyping in these two groups of antenatally-diagnosed cleft deformities.


Asunto(s)
Labio Leporino/epidemiología , Fisura del Paladar/epidemiología , Aneuploidia , Labio Leporino/etiología , Fisura del Paladar/etiología , Anomalías Congénitas/diagnóstico , Anomalías Congénitas/epidemiología , Síndrome de Down , Femenino , Predisposición Genética a la Enfermedad , Humanos , Cariotipificación , Masculino , Prevalencia , Sistema de Registros , Riesgo , Singapur , Síndrome
15.
Singapore Med J ; 49(4): 286-9, 2008 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-18418519

RESUMEN

INTRODUCTION: The 22q11 deletion syndrome (22q11DS) is associated with many congenital structural anomalies, notably cardiac defects (conotruncal anomalies) and velopharyngeal insufficiency, as well as neurodevelopmental and psychiatric findings in later life. Recent studies have tried to ascertain the true population incidence of this condition. However, this is difficult due to possible under-ascertainment from incomplete genetic testing in possible cases. The aim of this study is to investigate the local incidence and association of this deletion syndrome with other congenital structural anomalies, with emphasis on cardiac defects. METHODS: Data of 22q11 deletion cases born in 2000-2003 were retrieved from the Singapore National Birth Defects Registry (NBDR) and analysed. Data of congenital cardiac defect cases notified to NBDR in the same period were also retrieved and compared with the deletion cases. RESULTS: There were a total of 17 cases of 22q11DS in the four-year period 2000-2003, giving an overall incidence of 1.02 per 10,000 live-births or one in 9,804 births. 94 percent (16/17 cases) were associated with other structural anomalies, and of these, 68.8 percent (11/16 cases) had single system anomalies. Cardiac anomalies were the most common (100 percent). The deletion contributed to 0.86 percent (one in 116 cases) of all cardiac defects born during the same period. A higher contribution of this deletion was noted for interrupted aortic arch (10 percent), pulmonary atresia (12.7 percent) and truncus arteriosus (11.1 percent). CONCLUSION: In view of the high proportion of this deletion among certain cardiac defects, genetic testing should be made available to investigate the true burden and contribution of this deletion. As more genetic testing is done for this deletion, we are likely to see an increase in incidence, reflecting the true prevalence of this condition.


Asunto(s)
Cromosomas Humanos Par 22/genética , Eliminación de Gen , Cardiopatías Congénitas/epidemiología , Cardiopatías Congénitas/genética , Sistema de Registros , Femenino , Humanos , Incidencia , Recién Nacido , Masculino , Singapur/epidemiología
16.
Singapore Med J ; 48(9): 808-12, 2007 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-17728960

RESUMEN

INTRODUCTION: This study aims to assess the epidemiology of severe preeclampsia in Singapore, the disease characteristics, maternal and perinatal outcome, and to identify risk factors for complications. METHODS: Data of 93 consecutive women with severe preeclampsia in KK Women's and Children's Hospital in Singapore was collected prospectively and analysed using the unpaired t-test for normally-distributed continuous variables and Fisher's exact chi-square test for discrete variables. Multivariate logistic regression analysis was performed for prediction of complicated cases. RESULTS: The incidence of severe pre-eclampsia was 29.3 per 10,000 deliveries, with an increased risk in women who were aged more than 35 years and who were nulliparous. The risk was also increased in women of the Malay race and they also had the tendency to book later, compared with the other races. 43 percent of women had maternal complications, including eclampsia, haemolysis/elevated liver enzymes/low platelets syndrome, oliguria, pulmonary oedema and placental abruption. Significantly raised levels of uric acid (439.5 +/- 114.1 micromol/L versus 395.4 +/- 96.7 micromol/L, p-value equals 0.047) and aspartate transaminase (80.1 +/- 107.4 IU/L versus 38.8 +/- 16.1 IU/L, p-value equals 0.021) were found in those with complications, compared to those without complications. The average gestation at time of diagnosis was 33 weeks and the average gestation at delivery was 34 weeks. 89.3 percent of women required caesarean section and 59.1 percent of women were admitted to intensive care. CONCLUSION: Age, parity and race are risk factors for severe preeclampsia with increased levels of uric acid and aspartate transaminase found in the complicated cases. The morbidity and cost of treatment of severe preeclampsia are high with a large percentage requiring caesarean section and intensive care admission.


Asunto(s)
Preeclampsia/epidemiología , Adulto , Femenino , Humanos , Incidencia , Persona de Mediana Edad , Embarazo , Resultado del Embarazo , Estudios Retrospectivos , Factores de Riesgo , Singapur/epidemiología
17.
Obes Rev ; 8(4): 293-306, 2007 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-17578380

RESUMEN

The recent rapid increase in the prevalence of obesity across the world is undoubtedly due to changes in diet and lifestyle. However, it is also indisputable that different people react differently to this change in environment and this variation in response is likely to be genetically determined. While for the majority of people this effect is presumed to be polygenic in origin, there is now strong evidence for a small number of genes having a large effect in some families with severe obesity. Studies of these families, coupled with parallel studies in murine models, have provided novel insights into the molecules involved in the regulation of appetite, energy expenditure and nutrient partitioning. We review here the lessons we have learnt from mouse models of obesity, both naturally occurring and artificially generated through targeted gene deletions, and more importantly from human monogenic syndromes of obesity. These have illuminated the critical role in which the central leptin melanocortin pathway plays in the control of mammalian food intake and body weight.


Asunto(s)
Regulación del Apetito/genética , Peso Corporal/genética , Leptina/genética , Melanocortinas/genética , Obesidad/genética , Animales , Modelos Animales de Enfermedad , Metabolismo Energético/genética , Humanos , Ratones
18.
Singapore Med J ; 48(1): 12-5, 2007 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-17245510

RESUMEN

INTRODUCTION: Anencephaly is a neural tube defect that is incompatible with life. Previous studies have suggested that there is a racial predilection for this condition. However, local studies have not shown a statistical difference between the races. The aim of this study is to examine the incidence and the demographical trend of this condition over a ten-year period. METHODS: Data of patients with anencephaly born from 1993 to 2002 were retrieved from the National Birth Defect Registry and analysed. RESULTS: There were a total of 267 cases of anencephaly in the ten-year period from 1993 to 2002, giving an overall incidence of 0.58 per 1,000 livebirths, with a decreasing trend noted. The incidence was highest among the Malay population, compared with the Chinese population (p-value equals 0.03) and other races. Abortion rates have also increased over the years, causing a reduction in livebirth rates for this condition. CONCLUSION: The overall incidence and birth incidence of anencephaly has seen a decreasing trend over the last ten years, with the latter being contributed significantly by early termination. More studies should be done to ascertain if improved folate supplementation has contributed to the drop in overall incidence. The incidence in the Malay population is significantly higher than other races and this phenomenon should be further examined.


Asunto(s)
Anencefalia/epidemiología , Femenino , Humanos , Incidencia , Recién Nacido , Masculino , Embarazo , Resultado del Embarazo , Estudios Retrospectivos , Singapur/epidemiología
19.
Rheumatology (Oxford) ; 46(2): 232-7, 2007 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-16877465

RESUMEN

OBJECTIVES: How human leucocyte antigen B27 (HLA-B27) contributes towards arthritis susceptibility is still unclear, but effects on the response to bacteria unrelated to the classical antigen presenting role of B27 have been suggested. This study investigated whether HLA-B27 modulates the innate response to lipopolysaccharide (LPS), a component shared between all Gram negative bacteria that can trigger reactive arthritis. METHODS: Pools of U937 transfectants expressing either HLA-B27, HLA-A2 or the expression plasmid alone were differentiated with phorbol 12-myristate 13-acetate and stimulated with LPS. Supernatants were analysed for tumour necrosis factor-alpha (TNF-alpha) secretion and the gene expression profiles of unstimulated and LPS-stimulated cells were determined by microarray analysis. Changes in gene expression that are indicative of an unfolded protein response (UPR) were also analysed by quantitative polymerase chain reaction (PCR). RESULTS: TNF-alpha secretion, a biological marker of the inflammatory response to LPS, was not significantly different between U937-B27 and U937-control. No differences in gene expression between unstimulated U937-B27 and U937-control lines were detected. Both U937-control and U937-B27 exhibited a stereotypic response to LPS. Only one gene, OAS2, was differentially expressed by these cell lines, and this was confirmed by quantitative PCR. Analysis of XBP-1 splicing suggested that the UPR is induced following the LPS stimulation, but this increase was seen in all transfectants. CONCLUSIONS: The expression of B27 does not profoundly alter the gene expression following LPS stimulation. Therefore, additional signals, such as those provided by cytokines or intracellular infection, may be required to reveal any influence of B27 expression on the inflammatory response.


Asunto(s)
Antígeno HLA-B27/metabolismo , Mediadores de Inflamación/metabolismo , Lipopolisacáridos/farmacología , Monocitos/metabolismo , Perfilación de la Expresión Génica , Regulación de la Expresión Génica , Humanos , Monocitos/efectos de los fármacos , Reacción en Cadena de la Polimerasa/métodos , Pliegue de Proteína , ARN Mensajero/genética , Transfección , Factor de Necrosis Tumoral alfa/metabolismo , Células U937
20.
Singapore Med J ; 47(8): 728-9, 2006 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-16865218

RESUMEN

We report a case of recurrent neural tube defects in a 30-year-old multigravida with no medical or family history of note. She presented with a significant history of having three (out of four) previous pregnancies affected by neural tube defects diagnosed at the 20-week foetal anomaly ultrasonographical scans, and which resulted in mid-trimester pregnancy terminations. Previous investigations for the foetuses did not yield any obvious cause. We discuss the possible differential diagnoses and aetiological factors. Rare causes of neural tube defects need to be excluded in recurrent cases with no obvious aetiology.


Asunto(s)
Defectos del Tubo Neural/diagnóstico , Adulto , Diagnóstico Diferencial , Femenino , Humanos , Defectos del Tubo Neural/fisiopatología , Embarazo , Diagnóstico Prenatal , Recurrencia , Medición de Riesgo , Factores de Riesgo
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