Serum Retinol-Binding Protein-4 Levels Are Increased in HIV-Infected Subjects with Metabolic Syndrome Receiving Highly Active Antiretroviral Therapy

Metabolic syndrome is an important long term complication in chronic asymptomatic HIV-infected subjects under highly active antiretroviral therapy (HAART), because it can contribute to morbidity and mortality via cardiovascular disease (CVD). Therefore, a predictive marker for early detection of metabolic syndrome may be necessary to prevent CVD in HIV-infected subjects. Retinol-binding protein-4 (RBP-4) has been shown to be associated with metabolic syndrome in various non-HIV-infected populations. We performed a cross-sectional study to evaluate whether serum RBP-4 levels are correlated with metabolic syndrome in HIV-infected subjects receiving HAART. In total, 98 HIV-infected Koreans who had been receiving HAART for at least 6 months were prospectively enrolled. Metabolic syndrome was diagnosed according to the Adult Treatment Panel III criteria, and serum RBP-4 concentrations were measured using human RBP-4 sandwich enzyme-linked immunosorbent assay. Serum RBP-4 levels were significantly higher in HIV-infected subjects receiving HAART with metabolic syndrome (n=33, 33.9+/-7.7 microg/mL) than in those without it (n=65, 29.9+/-7.2 microg/mL) (p=0.012). In multivariate linear regression analysis, the number of components of metabolic syndrome presented and waist circumference were independently, significantly correlated with RBP-4 (p=0.018 and 0.030, respectively). In conclusion, we revealed a strong correlation between RBP-4 and the number of components of metabolic syndrome in HIV-infected subjects receiving HAART.

Serum retinol binding protein 4 is not decreased in congenital generalized lipodystrophy: a case series / Os níveis plasmáticos da retinol binding protein 4 (rbP4) não estão reduzidos na lipodistrofia congênita generalizada: uma série de casos

INTRODUCTION: Previous studies have suggested that Retinol Binding Protein 4 (RPB4), a protein produced by the adipose tissue, is associated with insulin resistance (IR). Congenital Generalized Lipodystrophy (CGL) is a rare disease characterized by IR and paucity of adipose tissue. Our objective was to determine RBP4 levels in patients with CGL. SUBJECTS AND METHODS: Six (6) patients with CGL and a healthy control group were selected to participate in the study. Anthropometric and biochemical variables were compared between groups. RESULTS: No difference was observed in RBP4 levels between the two groups (CGL 42.5 [12.5 - 127] vs. control 57.4 [15.9 - 165]; p = 0.78). On the other hand, leptin levels were significantly lower in CGL patients (CGL 0.65 [0.2 - 0.7] vs. control 10.9 [0.9 - 38.6]; p = 0.015). No correlation was found between RBP-4 and waist circunference (r = 0.18, p = 0.57), or BMI (r = 0.24, p = 0.45). CONCLUSION: RBP4 is not decreased in CGL. These results suggest that adipose tissue may not be the main source of RBP4.

INTRODUÇÃO: Estudos prévios sugeriram que os níveis plasmáticos da retinol binding protein (RBP4), uma proteína do tecido adiposo, estão associados com a resistência à insulina (RI). A lipodistrofia congênita generalizada (LCG) é uma doença rara caracterizada por ausência de tecido adiposo e RI. O objetivo é determinar os níveis de RBP4 em pacientes com LCG. SUJEITOS E MÉTODOS: Seis (6) pacientes com LCG e um grupo controle saudável foram selecionados para participar no estudo. As variáveis antropométricas e bioquímicas foram comparadas quando comparados os grupos. RESULTADOS: Nenhuma diferença foi observada entre os níveis de RBP4 log entre os grupos (LCG 42,5 [12,5 - 127] vs. controle 57,4 [15,9 - 165]; p = 0,78). Por outro lado, os níveis de leptina foram menores em pacientes com LCG (LCG 0,65 [0,2 - 0,7] vs. controle 10.9 [0,9 - 38,6]; p = 0,015). Nenhuma correlação foi encontrada entre RBP4 e cintura (r = 0,18, p = 0,57) ou IMC (r = 0,24, p = 0,45). CONCLUSÃO: RBP4 não está diminuída na LCG. Esses resultados sugerem que o tecido adiposo pode não ser a principal fonte de RBP4.

Discovery of the serum biomarker proteins in severe preeclampsia by proteomic analysis

Preeclapsia (PE) is a severe disorder that occurs during pregnancy, leading to maternal and fetal morbidity and mortality. PE affects about 3-8% of all pregnancies. In this study, we conducted liquid chromatographymass spectrometry/mass spectrometry (LC-MS/MS) to analyze serum samples depleted of the six most abundant proteins from normal and PE-affected pregnancies to profile serum proteins. A total of 237 proteins were confidently identified with < 1% false discovery rate from the two groups of duplicate analysis. The expression levels of those identified proteins were compared semiquantitatively by spectral counting. To further validate the candidate proteins with a quantitative mass spectrometric method, selective reaction monitoring (SRM) and enzyme linked immune assay (ELISA) of serum samples collected from pregnant women with severe PE (n = 8) or normal pregnant women (n = 5) was conducted. alpha2-HS-glycoprotein (AHSG), retinol binding protein 4 (RBP4) and alpha-1-microglobulin/bikunin (AMBP) and Insulin like growth factor binding protein, acid labile subunit (IGFBP-ALS) were confirmed to be differentially expressed in PE using SRM (P < 0.05). Among these proteins, AHSG was verified by ELISA and showed a statistically significant increase in PE samples when compared to controls.

Association of Serum Retinol Binding Protein 4 with Adiposity and Pubertal Development in Korean Children and Adolescents

Retinol binding protein 4 (RBP4) has been postulated to provide a new link between obesity and insulin resistance. We aimed to assess the relationship between serum RBP4 and insulin resistance by investigating serum RBP4 levels in children and adolescents according to degree of obesity and pubertal stage. A total of 103 (30 lean, 39 overweight, 34 obese) were evaluated for serum RBP4, adiponectin, insulin, glucose and lipid profiles. RBP4 levels of obese and overweight groups were higher than those of lean group. RBP4 level was higher in pubertal group than in prepubertal group. RBP4 was positively correlated with age, height, weight, body mass index (BMI), abdominal circumference, systolic blood pressure, fasting insulin, homeostatic model assessment of insulin resistance (HOMA-IR), total cholesterol and triglyceride, and inversely with adiponectin. In the multiple linear regression analysis, RBP4 was found to be independently associated with pubertal stage, BMI and triglyceride but not with HOMA-IR. In conclusion, serum RBP4 level is related with degree of adiposity and pubertal development. The association of RBP4 with insulin resistance is supposed to be secondary to the relation between RBP4 and adipose tissue in children and adolescents.

Association of Plasma Retinol-Binding Protein 4, Adiponectin, and High Molecular Weight Adiponectin with Insulin Resistance in Non-Diabetic Hypertensive Patients

PURPOSE: The aim of this study was to determine whether retinol-binding protein 4 (RBP4), adiponectin and high molecular weight (HMW) adiponectin are associated with insulin resistance (IR) and metabolic parameters in non-diabetic hypertensive patients. Also, we sought to compare the predictive values of these adipocytokines for IR in non-diabetic hypertensive patients. MATERIALS AND METHODS: Analyses of RBP4, adiponectin, and HMW adiponectin were performed on 308 non-diabetic hypertensives (148 males, age 58 +/- 10 years, 189 non-metabolic syndrome and 119 metabolic syndrome). The homeostasis model assessment (HOMA) index for IR, lipid profiles, and anthropometric measure-ments were assessed. RESULTS: There was no significant difference in RBP4 levels according to the presence of metabolic syndrome, although adiponectin and HMW adiponectin were significantly lower in metabolic syndrome. Correlation analysis of log RBP4 with IR and metabolic indices revealed that there was no significant correlation of RBP4 with waist circumference (r = 0.056, p = 0.324), HDL cholesterol (r = 0.005, p = 0.934), ApoB/ApoAI ratio (r = 0.066, p = 0.270), and the HOMA index (r = 0.017, p = 0.756). However, adiponectin and HMW adiponectin showed significant correlations with the HOMA index (r = - 0.247, p or = 2.5, HMW adiponectin did not demonstrate a superior predictive value for IR compared to adiponectin (AUC = 0.680 vs. 0.648, p = 0.083). The predictive value of RBP4 for IR was minimal (AUC = 0.534). CONCLUSION: RBP4 was not associated with IR or metabolic indices and the predictive value for IR was minimal in hypertensives. HMW adiponectin didn't have a superior predictive value for IR compared to adiponectin. Therefore, we can suggest that RBP4 and HMW adiponectin don't have more additive information than adiponectin in non-diabetic hypertensives.

Clinical Implications of Serum Retinol-Binding Protein 4 in Asthmatic Children

Recently the prevalence of both asthma and obesity have increased substantially in many countries. The aim of this study was to evaluate the role of retinol-binding protein (RBP) 4 in childhood asthma and its association with atopy markers, pulmonary function, and bronchial hyperresponsiveness in relation to obesity. We studied 160 children between the ages 6 to 10 yr, including 122 asthmatics and 38 controls. The body mass index, pulmonary function tests, and methacholine challenge tests were measured on the same day. Total eosinophil count, serum total IgE, serum eosinophil cationic protein, and serum RBP4 were measured in all subjects. There was no difference in serum RBP4 levels between the asthmatics and the control group. In all subjects or subgroups, serum RBP4 was not associated with total eosinophil count, serum total IgE, serum eosinophil cationic protein, or PC20. There was no relationship between serum RBP4 and pulmonary function in female asthmatics. Forced expiratory volume in 1 second/forced vital capacity (FVC) and forced expiratory flow between 25% and 75% of FVC contributed to serum RBP4 in male asthmatics. Our findings show an association between RBP4 and pulmonary function in prepubertal male asthmatics. This relationship may indirectly affect the high prevalence of childhood asthma in males.

Efeito da suplementação com vitamina A sobre a concentração de retinol no colostro de mulheres atendidas em uma maternidade pública / The effect of vitamin A supplementation upon retinol concentration in the colostrum of women in a public maternity hospital

OBJETIVOS: Avaliar o efeito da suplementação com vitamina A sobre os níveis de retinol no colostro de puérperas atendidas em maternidade pública de Natal-RN, analisando a influência do estado nutricional materno e retinol no colostro na resposta a esta suplementação. MÉTODOS: Foram coletados 5 ml de sangue em jejum para análise do retinol sérico, e duas amostras de leite, antes e 24h após suplementação. O consumo de vitamina A foi obtido pelo questionário de frequência de consumo. O retinol foi analisado por cromatografia líquida de alta eficiência. RESULTADOS: O consumo de vitamina A foi 1492,4 ± 1264 µgRAE/dia e 23 por cento tinha consumo provavelmente inadequado. No início (0h) e após 24h da suplementação, os grupos comparativo e suplementado apresentaram concentrações séricas de retinol de 1,3 ± 0,4 e 1,4 ± 0,4 µmol/L (7 por cento de deficiência) e 3,5 ± 1,7 µmol/L e 3,3 ± 1,8 µmol/L (p>0,05) no colostro 0h, respectivamente. No grupo suplementado o retinol aumentou no colostro 24h, com valores de 3,6 ± 1,9 e 6,8 ± 2,6 µmol/L (p<0,0001), respectivamente. Mulheres com níveis deficientes de retinol no colostro 0h (<2,04 µmol/L) transferiram mais retinol ao colostro 24h do que as com níveis adequados (326,1 por cento e 86,5 por cento de aumento, respectivamente). CONCLUSÃO: A megadose foi eficaz nas primeiras 24h após a suplementação. Os níveis basais de retinol no colostro influenciaram a resposta à suplementação. As parturientes que apresentaram valores baixos de retinol transferiram mais retinol oriundo da megadose ao leite do que as lactantes com níveis suficientes, possivelmente ressaltando a atuação dos mecanismos de transferência de vitamina A propostos na glândula mamária.

OBJECTIVE: The aim was to evaluate the effect of supplementary vitamin A upon the colostrum retinol levels in puerperal women cared for at a public maternity hospital in Natal, RN, Brazil. Analysis was conducted on the influence of the colostrum retinol and the maternal nutritional condition as response to supplementation. METHODS: For analysis of serum retinol 5ml of fasting blood and two samples of milk were collected before and 24 hours after supplementation. A questionnaire was used to define the frequency of previous vitamin A intake. High Efficiency Liquid Chromatography was used to analyze the retinol. RESULTS: Vitamin A intake was 1492.4 ± 1264 µgRAE/day and 23 percent probably had an inadequate intale. At the beginning of supplementation, 0 hour, and at 24 hours, the control and supplemented groups presented serum retinol concentrations of 1.3 ± 0.4 and 1.4 ± 0.4 µmol/L (7 percent deficiency) and 3.5 ± 1.7 µmol/L and 3.3 ± 1.8 µmol/L (p>0.05) at 0 hour colostrum, respectively. Retinol in the 24 hours milk of the supplemented group increased from of 3.6 ± 1.9 and 6.8 ± 2.6 µmol/L (p<0.0001), respectively. Women with deficient levels of retinol in the colostrum at 0 hour(<2.04 mol/L) transferred more retinol to the colostrum at24 hours milk than those with adequate levels (an increase of 326.1 percent and 86.5 percent, respectively). CONCLUSION: The megadose of vitamin A was efficient in the first 24 hours after supplementation. The supplementation response was influenced by the basal levels of retinol in the colostrum. Parturient women with low initial levels of retinol transferred more retinol to the milk, after the megadose, than nursing women with sufficient levels. This possibly confirms the action of the Vitamin A transfer mechanisms proposed by the mammary gland.