title: Effects of Body Weight Reduction on Serum Irisin and Metabolic Parameters in Obese Subjects.
abstract: BACKGROUND
  Irisin is a myokine implicated in lipid and glucose metabolism. The objective of this study is to examine the effect of a body weight reduction on the serum irisin level and physical indicators in obese Japanese patients without diabetes.
  
  
  METHODS
  The subjects were 22 patients (male/female, 5/17; age, 46.1±16.0 years; body mass index [BMI], 36.9±5.0 kg/m2) who completed a 6-month body weight reduction program at our clinic. The program included diet, exercise therapy and cognitive behavioral therapy. Blood parameters, body composition, exercise tolerance, homeostasis model assessment of insulin resistance (HOMA-IR), and serum irisin were determined before and after intervention, and relationships among changes in these data were examined.
  
  
  RESULTS
  There were significant decreases in body weight and BMI after the intervention. Irisin before the intervention was significantly positively correlated with HOMA-IR (r=0.434,P<0.05). The mean irisin level showed no significant change after the intervention in all participants. However, improvements in % body fat, subcutaneous fat area, triglycerides, and fasting glucose were significantly greater in patients with an increase in irisin compared to those with a decrease in irisin after the intervention. Patients with an increase in irisin also had significantly lower fasting insulin (9.7±4.8 vs. 16.4±8.2,P<0.05) and HOMA-IR (2.2±1.1 vs. 3.7±1.6,P<0.05) after the intervention, compared to patients with a decrease in irisin.
  
  
  CONCLUSIONS
  Body weight reduction did not alter irisin levels. However, irisin may play important roles in fat and glucose metabolism and insulin resistance, and the effects of body weight reduction on irisin kinetics may be a key for obesity treatment.
authors.affiliation: Department of Health Science, Kansai Medical University Graduate School of Medicine, Hirakata, Japan.
authors.forename: Yaeko
authors.identifier: 0000-0001-9677-8762
authors.initials: Y
authors.lastname: Fukushima
authors.affiliation: Department of Health Science, Kansai Medical University Graduate School of Medicine, Hirakata, Japan.; Disease Prevention Center, Ijinkai Takeda General Hospital, Kyoto, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Kurose
authors.affiliation: Department of Health Science, Kansai Medical University Graduate School of Medicine, Hirakata, Japan.
authors.forename: Hiromi
authors.initials: H
authors.lastname: Shinno
authors.affiliation: Department of Health Science, Kansai Medical University Graduate School of Medicine, Hirakata, Japan.
authors.forename: Ha Cao
authors.initials: HC
authors.lastname: Thi Thu
authors.affiliation: Department of Health Science, Kansai Medical University Graduate School of Medicine, Hirakata, Japan.
authors.forename: Nana
authors.initials: N
authors.lastname: Takao
authors.affiliation: Department of Health Science, Kansai Medical University Graduate School of Medicine, Hirakata, Japan.
authors.forename: Hiromi
authors.initials: H
authors.lastname: Tsutsumi
authors.affiliation: Department of Cardiovascular Medicine, Dokkyo Medical University, Tochigi, Japan.
authors.forename: Takaaki
authors.initials: T
authors.lastname: Hasegawa
authors.affiliation: Department of Cardiovascular Medicine, Dokkyo Medical University, Tochigi, Japan.
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Nakajima
authors.affiliation: Department of Health Science, Kansai Medical University Graduate School of Medicine, Hirakata, Japan.; Health Science Center, Kansai Medical University, Hirakata, Japan.
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Kimura
keywords: Body composition; Insulin resistance; Irisin; Lean muscle mass; Obesity