RESUMO
The aim of this study is to compare the effect of conventional bread and a whole grain bread on appetite and energy intake, satiety and satiety gut-hormones. A randomized controlled crossover pilot study was carried out in 11 university students (age: 18.7 ± 0.9 years; body mass index: 22.7 ± 2.7 kg/m(2)). Participants consumed two different mid-morning cereal-based snacks, including a conventional or whole grain bread. Two testing days were completed, including satiety questionnaires, blood sampling and consumption of standardized breakfast, mid-morning test-snacks and ad libitum lunch. Several gut-hormones were analysed and satiation was assessed using Visual Analogue Scale scores. The consumption of whole grain bread increased satiety perception, decreased the remained energy intake during the testing day, and decreased the postprandial response of peptide YY, compared with conventional bread (p < 0.005). These data suggest that the consumption of whole grain bread might be a useful strategy to improve satiety.
Assuntos
Apetite/fisiologia , Pão , Ingestão de Energia , Hormônios Gastrointestinais/sangue , Saciação/fisiologia , Adolescente , Índice de Massa Corporal , Carboidratos da Dieta/administração & dosagem , Carboidratos da Dieta/análise , Gorduras na Dieta/administração & dosagem , Gorduras na Dieta/análise , Fibras na Dieta/administração & dosagem , Fibras na Dieta/análise , Proteínas Alimentares/administração & dosagem , Proteínas Alimentares/análise , Feminino , Manipulação de Alimentos , Polipeptídeo Inibidor Gástrico/sangue , Grelina/sangue , Peptídeo 1 Semelhante ao Glucagon/sangue , Humanos , Insulina/sangue , Masculino , Avaliação Nutricional , Polipeptídeo Pancreático/sangue , Peptídeo YY/sangue , Projetos Piloto , Período Pós-Prandial , Lanches , Grãos Integrais , Adulto JovemRESUMO
Connective tissue growth factor (CTGF/CCN2) is a cysteine-rich, extracellular matrix (ECM) protein that acts as an anabolic growth factor to regulate osteoblast differentiation and function. Recent studies have identified CTGF as a downstream effector of transforming growth factor-beta1 (TGF-beta1) for certain functions in specific cell types. In this study, we examined the role of CTGF as a downstream mediator of TGF-beta1-induced ECM production and cell growth in osteoblasts. Using primary cultures, we demonstrated that TGF-beta1 is a potent inducer of CTGF expression in osteoblasts, and that this induction occurred at all stages of osteoblast differentiation from the proliferative through mineralization stages. TGF-beta1 treatment of osteoblasts increased the expression and synthesis of the ECM components, collagen and fibronectin. When CTGF-specific siRNA was used to prevent TGF-beta1 induction of CTGF expression, it also inhibited collagen and fibronectin production, thereby demonstrating the requirement of CTGF for their up-regulation. To examine the effects of TGF-beta1 on osteoblast cell growth, cultures were treated with TGF-beta1 during the proliferative stage. Cell number was significantly reduced and the cells exhibited a decrease in G1 cyclin expression, consistent with TGF-beta1-induced cell-cycle arrest. Cultures transfected with CTGF siRNA prior to TGF-beta1 treatment showed an even greater reduction in cell number, suggesting that TGF-beta1-induced growth arrest is independent of CTGF in osteoblasts. Collectively, these data demonstrate for the first time that CTGF is an essential downstream mediator for TGF-beta1-induced ECM production in osteoblasts, but these two growth factors function independently regarding their opposing effects on osteoblast proliferation.