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| Author(s): |
Cristiane Martins Moulin de Moraes
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | São Paulo. |
| Institution: | Universidade de São Paulo (USP). Faculdade de Medicina (FM/SBD) |
| Defense date: | 2008-11-28 |
| Examining board members: |
Alfredo Halpern;
Valquiria Bueno;
Edna Regina Nakandakare;
Márcia Nery;
João Eduardo Nunes Salles
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| Advisor: | Alfredo Halpern |
| Field of knowledge: | Health Sciences - Medicine |
| Indexed in: | Banco de Dados Bibliográficos da USP-DEDALUS; Biblioteca Digital de Teses e Dissertações - USP |
| Location: | Universidade de São Paulo. Biblioteca Central da Faculdade de Medicina; FM W4.DB8 SP.USP FM-2 2008; M819av |
| Abstract | |
Although obesity is related to immune dysfunction, with a higher incidence of infections and some types of cancer, few studies have evaluated immunological parameters in severely obese patients. Moreover, a limited set of studies have analyzed the effect of weight loss in immunological parameters in severely obese patients. Thus, the objective of this thesis was to evaluate the influence of weight loss induced by Roux en-Y gastric bypass in patients with grade III obesity in immunological parameters. The production of cytokines associated with acquired (IL-2, IL-4, IL-10 and IFN-) and innate (TNF- e IL-6) immune responses from peripheral blood mononuclear cells (PBMCs), the profile of lymphocytes populations and the cytotoxic activity of natural killer cells (NK), besides cytokines related with NK cell cytotoxic function and development (IL-12 e IL-18), were analyzed in 28 non-diabetic and sedentary patients with grade III obesity (20 women and 8 men, 39,9 ± 10,9 years and BMI 49,5 ± 7,1 kg/m2) before and 6 months after RYGB. PBMCs were stimulated with the mitogen phytohemagglutinin (PHA) and cytokines were measure by ELISA. The profile of lymphocytes populations was evaluated by flow cytometry. NK cell cytotoxicity was determined by the lactate dehydrogenase release assay from K562 lysed target cells. The weight loss 6 months after surgery was 35.3±4.5 kg and there was a significant post-surgical decrease in BMI at this point (-12.9±0.9 kg/m2, p<0.001). No significant differences were found in the lymphocytes populations after surgery. It was observed a significant increase in the lymphocytes proliferation six months after surgery (p= 0.0026). There was also a post-surgical increase in the production of IFN-, IL-12 e IL-18 from PBMC stimulated with PHA, while there was a trend towards the increase of the IL-2 production (p=0.07). The other cytokines analyzed were not altered. Cytotoxic activity of NK cells was significantly enhanced 6 months after RYGB [17.1±14.7% before RYGB vs 51.8±11.3% at 6 months after, at effector to target cell (NK cell:K562 cell) ratio 40:1; p<0.001], and it was in the same range when compared to data obtained from controls with normal BMI matched for age and gender (45,4 ± 7,8% at NK cell:K562 cell ratio 40:1). There was a significant post-surgical improvement in all points of the cytotoxic activity curve in almost 79% of the sample (22 patients). In conclusion, the data obtained show that the weight loss induced by RYGB increases the production of cytokines related with NK cell cytotoxic function and improves its activity. The impairment in NK cells cytotoxic activity and cytokines observed in patients with severe obesity may explain their propensity to develop infections and cancer. Our data suggests that the weight loss induced by bariatric surgery can positively impact these factors. (AU) | |