Irisin is weakly associated with usual physical activity in young overweight women

PURPOSE: To determine if irisin plasma levels are associated with regular physical activity, body composition and metabolic parameters in women subjected to calorie restriction. SUBJECTS AND METHODS: We studied 42 women aged 34 ± 13 years with a body mass index of 27.7 ± 1.8 kg/m2, who were subjected to a calorie restriction for three months. At baseline and at the end of the study, weight, waist and hip circumference, laboratory parameters, body composition by DEXA, resting and activity energy expenditure by indirect calorimetry and 72 hours actigraphy were measured. Fasting serum irisin was quantified using an ELISA kit. RESULTS: After the intervention period, participants lost 1.5 (0.4-3.4) kg and irisin levels did not change. Irisin baseline levels were positively but weakly correlated with the level of physical activity. This association was lost at the end of the intervention. No association was found between irisin levels and body composition or insulin sensitivity or their changes after calorie restriction. No association between serum irisin levels and PGC-1αexpression in peripheral blood mononuclear cells and serum irisin was observed. CONCLUSIONS: Fasting serum irisin was weakly associated with usual physical activity and did not change after calorie restriction.

Irisin is weakly associated with usual physical activity in young overweight women / La irisina se asocia débilmente con la actividad física habitual en mujeres jóvenes con sobrepeso

Purpose: To determine if irisin plasma levels are associated with regular physical activity, body composition and metabolic parameters in women subjected to calorie restriction. Subjects and methods: We studied 42 women aged 34 ± 13 years with a body mass index of 27.7 ± 1.8 kg/m2, who were subjected to a calorie restriction for three months. At baseline and at the end of the study, weight, waist and hip circumference, laboratory parameters, body composition by DEXA, resting and activity energy expenditure by indirect calorimetry and 72 hours actigraphy were measured. Fasting serum irisin was quantified using an ELISA kit. Results: After the intervention period, participants lost 1.5 (0.4-3.4) kg and irisin levels did not change. Irisin baseline levels were positively but weakly correlated with the level of physical activity. This association was lost at the end of the intervention. No association was found between irisin levels and body composition or insulin sensitivity or their changes after calorie restriction. No association between serum irisin levels and PGC-1α expression in peripheral blood mononuclear cells and serum irisin was observed. Conclusions: Fasting serum irisin was weakly associated with usual physical activity and did not change after calorie restriction (AU)

Objetivo: determinar si los niveles plasmáticos de irisina se asocian con la actividad física regular, composición corporal y parámetros metabólicos en mujeres sometidas a restricción calórica. Material y métodos: estudiamos 42 mujeres de 34 ± 13 años con un índice de masa corporal de 27,7 ± 1,8 kg/m2, quienes fueron sometidas a una restricción calórica durante tres meses. Al comienzo y final del estudio, se midieron peso, circunferencias de cintura y cadera, parámetros de laboratorio, composición corporal usando DEXA y gasto energético en reposo y en actividad mediante calorimetría indirecta y actigrafía. La irisina en ayunas se midió utilizando un kit ELISA. Resultados: después del periodo de intervención, las participantes bajaron 1,5 (0,4-3,4) kg y los niveles de irisina no cambiaron. La irisina basal se relacionó de forma positiva pero débil con el nivel de actividad física de las participantes. Esta asociación se perdió al final de la intervención. No se encontró una asociación entre los niveles de irisina y la composición corporal o sensibilidad a insulina o el cambio de estos parámetros después del periodo de restricción calórica. No se observó asociación entre los niveles de irisina y la expresión de PGC-1α en monocitos periféricos. Conclusiones: La irisina en ayunas se asoció débilmente con la actividad física habitual y no cambió después de la restricción calórica (AU)