The relationship between circulating irisin, retinol binding protein-4, adiponectin and inflammatory mediators in patients with metabolic syndrome

ABSTRACT Objective We wanted to investigate whether there is a relationship between circulating irisin, retinol binding protein-4 (RBP-4), adiponectin and proinflammatory mediators implicated in the development of insulin resistance (IR) in metabolic syndrome (MetS). Subjects and methods In 180 individuals, including controls and patients with MetS, we measured fasting plasma insulin, high sensitivity C-reactive protein (hsCRP), pentraxin-3 (PTX-3), interleukin-33 (IL-33), irisin, RBP-4, and adiponectin using ELISA kits. Results While fasting plasma hsCRP, PTX-3, IL-33, irisin, RBP-4 concentrations were higher, adiponectin levels were lower in patients with MetS than in controls. A correlation analysis revealed that plasma irisin levels were positively associated with MetS components such as waist circumference and waist-hip ratio, low density lipoprotein (LDL) and markers of systemic inflammation such as PTX-3, hsCRP, uric acid, and RBP-4. Adiponectin levels were negatively associated with waist circumference, waist-hip ratio, PTX-3 and LDL. Conclusions Although the precise mechanisms are still unclear, irisin, RBP-4, adiponectin and PTX-3 are hallmarks of the MetS, which is related to low-grade inflammation. It is conceivable that irisin and adiponectin might contribute to the development of MetS and may also represent novel MetS components. Future clinical studies are needed to confirm and extend these data.

Circulating omentin-1 might be associated with metabolic health status in different phenotypes of body size

ABSTRACT Objective Adipokines are mediators of body composition and are involved in obesity complications. This study aimed to assess the association of circulating omentin-1, vaspin, and RBP-4 with body composition indices and metabolic health status (MHS) in different phenotypes of body size. Subjects and methods A total of 350 subjects were included in the current cross-sectional study. Body composition was measured using a body composition analyzer, and serum concentrations of omentin-1, vaspin, and RBP-4 were assessed by ELISA kits. Results Circulating omentin-1 was significantly (OR = 1.81, 95% CI: 1.00-1.91, P = 0.01) and marginally (OR = 1.63, 95%CI: 1.00-1.75, P = 0.06) associated with MHS in the overweight and obese subjects, respectively. But no association was seen between omentin-1 and MHS in normal-weight subjects. Serum levels of vaspin and RBP-4 were not correlated with MHS. Furthermore, a significant positive correlation was observed between circulating omentin-1 and body mass index (BMI) as well as fat percentage (P = 0.02) in the MHS group. Serum vaspin concentrations were not related to body composition components in both groups. In addition, in the MHS group, circulating RBP-4 was positively correlated with fat percentage and fat mass (FM) (p < 0.0001) and was negatively correlated with fat-free mass (FFM) and total body water (TBW) (p < 0.0001). In contrast, in the metabolically unhealthy group, RBP-4 was negatively correlated with fat percentage, FM, and BMI (p < 0.0001) and was positively correlated with FFM and TBW (p < 0.0001). Conclusions This study showed that circulating levels of omentin-1 are useful predictors of metabolic health status in overweight and obese people.

Retinol binding protein 4 and incident diabetes the Atherosclerosis Risk in Communities Study (ARIC Study) / Proteina carreadora de retinol 4 e diabetes incidente Atherosclerosis Risk in Communities Study (ARIC Study)

Background: Retinol binding protein 4 (RBP4) has been described as a link between impaired glucose uptake in adipocytes and systemic insulin sensitivity. Objective: To determine whether RBP4 fasting levels predict the development of type 2 diabetes. Methods: Using a case-cohort design, we followed 543 middle-aged individuals who developed diabetes and 537 who did not over ~9 years within the population-based Atherosclerosis Risk in Communities Study. Weighted Cox proportional hazards analyses permitted statistical inference of the RBP4 – incident diabetes associations to the entire cohort. Results: Women in the highest tertile of RBP4 presented greater risk of developing diabetes (HR = 1.74; 95%CI 1.03 – 2.94) in analyses adjusted for age, ethnicity, study center, parental history of diabetes, hypertension, glomerular filtration rate, body mass index, waist-hip ratio, nonesterified fatty acids, adiponectin, leptin, triglycerides and HDL-C. When additionally adjusted for fasting insulin, this association's significance became borderline (HR = 1.68; 95%CI 1.00 – 2.82). No association between RBP4 levels and incident diabetes was found in men. Conclusion: These findings suggest that RBP4 levels may be directly involved in the pathogenesis of type 2 diabetes in women. .

Introdução: A proteína carreadora de retinol 4 (RBP4) tem sido descrita como elo entre uma menor captura de glicose pelos adipócitos e sensibilidade sistêmica à insulina. Objetivo: Determinar se os níveis de RBP4 em jejum predizem diabetes tipo 2. Método: Em um delineamento de caso-coorte, foram acompanhados 543 indivíduos de meia-idade que desenvolveram diabetes e 537 que não desenvolveram diabetes ao longo de 9 anos no estudo Atherosclerosis Risk in Communities Study (ARIC). Foi realizada análise ponderada de riscos proporcionais de Cox para inferência estatística da associação entre os níveis de RBP4 e diabetes incidente na coorte. Resultados: Mulheres com níveis de RBP4 no terceiro tercil apresentaram maior risco de desenvolver diabetes (HR = 1,74; 95% CI 1,03 – 2,94) em análises ajustadas para idade, etnia, centro, história familiar de diabetes, hipertensão, taxa de filtração glomerular, índice de massa corporal, razão cintura-quadril, níveis de ácidos graxos não esterificados, adiponectina, leptina, triglicerídeos e HDL-C. Quando adicionalmente ajustado para os níveis de insulina de jejum, a significância dessa associação se tornou limítrofe (HR = 1,68; 95% CI 1,00 – 2,82). Nenhuma associação foi observada entre RBP4 e diabetes incidente em homens. Conclusão: Esses achados sugerem que os níveis de RBP4 possam estar diretamente envolvidos na patogênese do diabetes tipo 2 em mulheres. .

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.

Vitamina A e diabetes gestacional: [revisão] / Vitamin A and gestational diabetes: [review]

O diabetes mellitus (DM), patologia de caráter crônico e evolutivo, atualmente apresenta configuração de epidemia mundial. O diabetes gestacional, condição associada tanto à resistência à insulina quanto à diminuição da função das células-β, também caracteriza-se pela elevada incidência em diversas populações e grupos étnicos. Recentemente têm sido constatadas fortes evidências para o comprometimento dos níveis de retinol de gestantes com DM em resposta à evolução dessa patologia. Essa condição torna as gestantes diabéticas mais propensas a apresentar estado bioquímico marginal ou deficiente em vitamina A quando comparadas com as de gestação saudável. Dessa maneira, tendo conhecimento sobre o papel fisiológico da vitamina A e as consequências do DM na gestação, esta revisão visa esclarecer o impacto da instalação do DM sobre os níveis de retinol dessas gestantes, bem como, as consequências que o estado de deficiência em vitamina A poderá causar para essas mulheres e para seus lactantes.

Diabetes mellitus (DM) a pathology with chronic evolution, has now acquired a connotation of global epidemic. Gestational diabetes, a condition associated with insulin resistance and decreased β-cells function is also characterized by a high incidence in different populations and ethnic groups. Recently strong evidence has been found for involvement of retinol levels of pregnant women with DM due to the pathology’s evolution. This condition makes these diabetics prone to have a marginal biochemical profile or a vitamin A deficiency when compared to those of healthy pregnant women. Therefore, with an awareness of the physiological role of vitamin A and consequences of diabetes during pregnancy, this review intends to clarify the impact of DM on retinol levels of these pregnant women and the consequences that vitamin A deficiency may cause to these women and their infants.

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.

The value of serum retinol-binding protein 4 levels for determining disease severity in patients with chronic liver disease / 대한간학회지

BACKGROUNDS/AIMS: Serum retinol-binding protein 4 (RBP4) is known to be a specific transport protein for retinol, and has recently been reported to be associated with insulin resistance. Hyaluronic acid (HA) is a well-known marker of liver fibrosis. In this study, the degree to which serum RBP4 levels can be used to predict disease severity in patients with chronic liver disease (CLD) was evaluated. METHODS: Serum levels of RBP4 and HA were measured in 573 CLD patients [235 with chronic hepatitis (CH), 230 with liver cirrhosis Child-Pugh grade (Child) A, and 108 with liver cirrhosis with Child B and C] and 40 normal controls. RESULTS: The mean age of the whole cohort was 53.1 years and the causes of CLD were hepatitis B virus (61.9%), hepatitis C virus (9.8%), alcohol (9.0%), and nonalcoholic steatohepatitis (3.8%). Serum levels of RBP4 significantly reduced and HA increased with disease condition, from none (normal controls) to advanced cirrhosis (normal control: RBP4 4.3+/-0.1 mg/dL, HA 25.3+/-28.1 ng/mL; CH: RBP4 3.6+/-0.1 mg/dL, HA 75.5+/-7.8 ng/mL; cirrhosis with Child A: RBP4 2.6+/-0.1 mg/dL, HA 184.4+/-14.5 ng/mL; and cirrhosis with Child B and C: RBP4 1.6+/-0.1 mg/dL, HA 656.5+/-86.7 ng/mL; P<0.001, respectively). Serum RBP4 level was a distinguishing factor at the early stage of CLD between CH and Child A cirrhosis (post-hoc test; P<0.001) and was correlated with histological fibrosis score (n=80, P<0.05) and several biochemical factors. Antiviral therapy (n=45, median interval 1,205 days) resulted in an improvement in serum RBP4 levels (P=0.001). CONCLUSIONS: The results of our study suggest that RBP4 is a serologic marker for disease severity in patients with CLD. It could also be useful as an early marker of CLD and of the relative success of antiviral therapy.