Effect of diet and physical exercise on weight, body composition, and resting metabolic rate in obese chilean adults

ABSTRACT Background: Diet and exercise are the mainstay of weight reduction programs. Aim: To evaluate the effect of diet and exercise on body weight and composition and resting metabolic rate (RMR) in obese adults. Material and Methods: Twenty-eight obese adults aged 22 to 61 years (18 women) completed four months of diet and exercise. They attended monthly nutritional consultations, and two-three weekly exercise sessions. At baseline and the end of the intervention, anthropometry, body composition by bioimpedance and RMR by indirect calorimetry (IC) were measured. Metabolic adaptation, defined as a decrease in thermogenesis to an extent greater than predicted based on the change in body weight and composition, was calculated. RESULTS: Significant reductions in body weight and fat mass were observed in both genders. Fat-free mass decreased in women and remained unchanged in men. RMR remained stable. Metabolic adaptation was observed in 11/27 participants. Fat mass change in participants with and without metabolic adaptation was 8 Kg and 4,4 kg, respectively (p = 0,018). In the linear regression analysis, male sex accounted for a higher RMR (247.80 Kcal, p = 0,006) than females. For each kg of fat and fat free mass, the RMR varies 7.25 Kcal, (p = 0.02) and 9.79 Kcal (p = 0,006), respectively. CONCLUSIONS: The intervention reduced body weight and fat mass and maintained RMR. Fat free mass decreased in women. Participants with metabolic adaptation showed greater changes in fat mass.

ANTECEDENTES: Para el tratamiento de la obesidad, la dieta y ejercicio físico (EF) contribuyen a reducir el peso corporal (PC), masa grasa (MG) y a mantener la masa libre de grasa (MLG) y tasa metabólica en reposo (TMR). Objetivo: Evaluar el efecto de la dieta y EF sobre el PC, composición corporal (CC), TMR y la presencia de adaptación metabólica. MATERIAL Y MÉTODOS: Veintiocho adultos obesos completaron cuatro meses de dieta y EF. Los adultos asistieron a consulta nutricional mensual y a 2-3 sesiones de EF semanal. En el período basal y después de la intervención se midió antropometría, CC por bioimpedanciometria y TMR por calorimetría indirecta. Se calculo la presencia de adaptación metabólica, definida como una disminución de la termogénesis mayor que la predicha por el cambio en peso y composición corporal. Resultados: Se observó una disminución significativa de PC y MG en hombres y mujeres. La MLG disminuyó en las mujeres y se mantuvo en los hombres. La TMR se mantuvo estable. Se observó adaptación metabólica en 11/27 participantes y una relación significativa con el cambio en MG (p = 0,018). En la regresión lineal, el sexo masculino da cuenta de una mayor TMR (247,80 Kcal, p = 0,006) que el sexo femenino. Por cada kg de MG y MLG la TMR varía 7,25 Kcal, (p = 0,02) y 9,79 Kcal, (p = 0,006) respectivamente. CONCLUSIONES: La intervención redujo el PC y la MG, y mantuvo TMR. La MLG disminuyó en las mujeres. Los sujetos con adaptación metabólica mostraron mayores cambios de MG.

Effect of diet and physical exercise on weight, body composition, and resting metabolic rate in obese chilean adults.

BACKGROUND: Diet and exercise are the mainstay of weight reduction programs. AIM: To evaluate the effect of diet and exercise on body weight and composition and resting metabolic rate (RMR) in obese adults. MATERIAL AND METHODS: Twenty-eight obese adults aged 22 to 61 years (18 women) completed four months of diet and exercise. They attended monthly nutritional consultations, and two-three weekly exercise sessions. At baseline and the end of the intervention, anthropometry, body composition by bioimpedance and RMR by indirect calorimetry (IC) were measured. Metabolic adaptation, defined as a decrease in thermogenesis to an extent greater than predicted based on the change in body weight and composition, was calculated. RESULTS: Significant reductions in body weight and fat mass were observed in both genders. Fat-free mass decreased in women and remained unchanged in men. RMR remained stable. Metabolic adaptation was observed in 11/27 participants. Fat mass change in participants with and without metabolic adaptation was 8 Kg and 4,4 kg, respectively (p = 0,018). In the linear regression analysis, male sex accounted for a higher RMR (247.80 Kcal, p = 0,006) than females. For each kg of fat and fat free mass, the RMR varies 7.25 Kcal, (p = 0.02) and 9.79 Kcal (p = 0,006), respectively. CONCLUSIONS: The intervention reduced body weight and fat mass and maintained RMR. Fat free mass decreased in women. Participants with metabolic adaptation showed greater changes in fat mass.

Efecto del 27- hidroxicolesterol en la acción antiplaquetaria de estradiol en mujeres postmenopáusicas / 27- Hydroxycholesterol reverses estradiol induced inhibition of platelet aggregation in postmenopausal women

Background: The decline of estrogen levels increases cardiovascular risk in women. Platelets express estrogen receptors and 17β-estradiol- (E2) can produce a protective effect on thrombus formation. The hydroxylation of cholesterol generates several sterols and 27-hydroxycholesterol (27HC) predominates in circulation. Aim: To evaluate the effect of 27HC as an endogenous antagonist of the anti-aggregating properties of E2 in platelets of postmenopausal women. Material and Methods: Platelet function of postmenopausal women was evaluated ex-vivo. Platelets pre-incubated with 27HC in the presence or absence of E2, were stimulated with collagen. Aggregation was evaluated using turbidimetry using a Chrono-log aggregometer. Results: Collagen-stimulated platelet aggregation was significantly inhibited by E2. The inhibitory effect of E2 on collagen-stimulated platelet aggregation was significantly reversed in the presence of 27HC. Conclusions: The suppressive effect of E2 on platelet aggregation is inhibited by 27HC, which could contribute to increase cardiovascular risk in postmenopausal women.

[27- Hydroxycholesterol reverses estradiol induced inhibition of platelet aggregation in postmenopausal women]. / Efecto del 27- hidroxicolesterol en la acción antiplaquetaria de estradiol en mujeres postmenopáusicas.

BACKGROUND: The decline of estrogen levels increases cardiovascular risk in women. Platelets express estrogen receptors and 17ß-estradiol- (E2) can produce a protective effect on thrombus formation. The hydroxylation of cholesterol generates several sterols and 27-hydroxycholesterol (27HC) predominates in circulation. AIM: To evaluate the effect of 27HC as an endogenous antagonist of the anti-aggregating properties of E2 in platelets of postmenopausal women. MATERIAL AND METHODS: Platelet function of postmenopausal women was evaluated ex-vivo. Platelets pre-incubated with 27HC in the presence or absence of E2, were stimulated with collagen. Aggregation was evaluated using turbidimetry using a Chrono-log aggregometer. RESULTS: Collagen-stimulated platelet aggregation was significantly inhibited by E2. The inhibitory effect of E2 on collagen-stimulated platelet aggregation was significantly reversed in the presence of 27HC. CONCLUSIONS: The suppressive effect of E2 on platelet aggregation is inhibited by 27HC, which could contribute to increase cardiovascular risk in postmenopausal women.

Preadipocyte proliferation is elevated by calcium sensing receptor activation.

Obesity is a major worldwide problem, despite considerable efforts against it. While excess body fat defines obesity, adipose tissue quality and functionality are key to whether cardiovascular and metabolic comorbidities develop. Adipose tissue cellular composition can vary considerably, and excess adipocyte progenitors (preadipocytes) is associated with obesity. We have proposed that calcium sensing receptor (CaSR) activation in adipose tissue leads to dysfunction. This study evaluated whether CaSR activation elevates preadipocyte proliferation. Human LS14 preadipocytes were exposed to CaSR activators cinacalcet (2 µM), GdCl3 (5 µM) and spermine (1 µM), and cell viability was evaluated after 72h. CaSR activators elevated proliferation by 19-24%, and CaSR silencing (siRNA) abolished the effect. Cinacalcet elevated phospho-ERK1/2 content, and upstream inhibition of ERK1/2 phosphorylation reverted cinacalcet-induced proliferation. Cinacalcet also elevated expression of the proinflammatory factors IL1ß, IL6 and CCL2. The results suggest that CaSR induces preadipocyte proliferation, partly through ERK1/2 activation. Considering reported proinflammatory and adipogenic CaSR effects, excess preadipocyte proliferation further supports the dysfunctional effect of CaSR in obesity.