Positive association between phase angle and protein oxidation in patients undergoing sleeve gastrectomy
Name: FERNANDA AMORIM VENANCIO
Publication date: 19/08/2019
Advisor:
Name |
Role |
|---|---|
| FABIANO KENJI HARAGUCHI | Advisor * |
| ROGERIO GRACA PEDROSA | Co-advisor * |
Examining board:
| Name |
Role |
|---|---|
| FABIANO KENJI HARAGUCHI | Advisor * |
| LUCIANE BRESCIANI SALAROLI | Internal Alternate * |
| MIRIAM CARMO RODRIGUES BARBOSA | Internal Examiner * |
| ROGERIO GRACA PEDROSA | Co advisor * |
| VALERIO GARRONE BARAUNA | External Examiner * |
Summary: The phase angle is used to evaluate cellular integrity and as a health indicator in several clinical conditions, such as in patients undergoing bariatric surgery. Sleeve gastrectomy, a bariatric surgery technique, promotes weight loss, which may contribute to reduction of inflammation and oxidative damage. Thus, the hypothesis of this study is that weight loss after bariatric surgery promotes the reduction of oxidative damage markers concentrations and that these are inversely associated with phase angle. The aim of this study was to evaluate the phase angle, oxidative damage and its associations in patients undergoing to sleeve gastrectomy, between the preoperative period and the rapid weight loss phase. Data were collected approximately one month before surgery (M0), two (M1) and six months after surgery (M2). Body weight, height, lean mass, fat mass and phase angle were obtained. The bioelectrical impedance was used to estimate lean mass, fat mass and determine the phase angle. Blood samples were obtained to analyze serum concentrations of malondialdehyde (MDA) and advanced oxidation protein products (AOPP). The ANOVA for repeated measures test were used or Friedman test, according to the normality of the data, followed by the Bonferroni test and Pearson (parametric data) or Spearman correlations (non-parametric data). The level of significance was set at p<0,05. The sample consisted of 14 participants. According to the results, body weight, lean mass, fat mass and phase angle were significantly reduced between moments (p<0,05). Serum AOPP concentration and AOPP/ALB ratio decreased between moments M0 and M1 (p <0,05). There was no significant reduction in the serum concentration of MDA and the MDA/TGL ratio (p> 0,05). A weak positive correlation was found between phase angle and serum AOPP concentration, considering the data of the three moments (n=42; r=0,354; p=0,021). When we evaluated the correlations at each moment, we found a moderate positive correlation between phase angle and serum AOPP concentration in M0 (r=0,613, p=0,020) and M1 (r=0,554, p=0,040). The correlation between phase angle and AOPP/ALB ratio was positive moderate in M0 (r=0,615; p=0,019). There was no significant correlation between the phase angle and the other variables (p>0,05). Thus, it is concluded that during the rapid phase of weight loss there was a reduction in phase angle as well as oxidative damage to proteins. Reducted protein oxidation indicates clinical improvement of health status and this reduction is positively associated with the phase angle.
