Evaluation Of Appetite In Obese Patients After Bariatric Surgery And The Factors For Clinical Benefits

Objective:Using the three-factor eating questionnaire and functional magnetic resonance imaging to evaluate the changes of appetite in obese patients and patients underwent vertical sleeve gastrectomy.Study the underlying mechanism by measuring gut hormones and adipokinesMethods:The study of three-factor eating questionnaire and functional magnetic resonance imaging included 20 cases of normal control,34 cases of obese patients and 12 cases underwent vertical sleeve gastrectomy.The study of appetite-related gut hormones and adipokines included 15 cases of normal control,15 cases of obese patients without diabetes,15 cases of obese patients with diabetes,and 15 cases underwent vertical sleeve gastrectomy.Functional magnetic resonance imaging was performed by BOLD signal.Gut hormones and adipokine were measured by plasma synchronous to OGTTResults:1.The three-factor eating questionnaire showed that obese patients had higher scores in disinhibition and hunger.The scores in those two factors were down regulated after sleeve gastrectomy2.Functional magnetic resonance imaging results showed that activation significantly decreased in some brain areas including Paracentral lobule,Right superior frontal gyrus,dorsolateral(Inhibition and control),Thalamus(Sensory),and Middle occipital gyrus(Vision).The activation in orbital part of right superior frontal gyrus,and medial of left superior frontal gyrus,(Reward system)decreased after surgery.3.Ghrelin levels in obese patients were significantly lower than those in normal controls at all time points of OGTT,and decreased significantly after the sleeve gastrectomy.4.Amylin was significantly increased after the glucose load in the group of simple obesity,and there is no difference between the group of obesity with type 2 diabetes and the normal controls.It decreased significantly after surgery.5.Leptin levels in obese patients were significantly higher than those in normal controls at all time points of OGTT,and decreased significantly after the sleeve gastrectomy.6.Obese patients had higher PYY than the normal controls after glucose load,and increase after the sleeve gastrecromy.7.GIP was significantly higher after glucose load in obese patients than in normal controls.At OGTT120min,it was significantly reduced in postoperative patients.8.There was no significant difference in GLP-1 between normal controls,simple obesity and obesity with type 2 diabetes mellitus,and GLP-1 was significantly increased after sleeve gastrectomy.9.GLP-1 at each time point after glucose load was negatively correlated with the scores of disinhibition in the three-factor eating questionnaire..Conclusion:By the three-factor eating questionnaire,we found that obese patients were more susceptible to hunger than normal controls,and their inhibition were weaker and they are easier to eat out of control.Using fMRI,we found that the activations of brain areas relative to inhibition in obese patients are significantly reduced.This is an objective description of appetite through brain activation.Through a comprehensive assessment of hormones,we found that the mechanism may be related to appetite-related gut hormones and adipokines.At the same time,we assessed the appetite of obesity patients underwent sleeve gastrectomy by questionnaire,fMRI and hormones and found that postoperative Ghrelin decreased,GLP-1 increased and PYY increased.Those hormones may act to the central nervous system through“Gut-Brain Axis" to suppress appetite.We also found that GLP-1 was negatively correlated with the scores of disinhibition in the questionnaire,so GLP-1 may be the key factor of appetite regulation after sleeve gastrectomy.Although other hormones such as GIP,Amylin and Leptin have an effect on appetite,but they may not be the main factor in the reduction of appetite after surgeryOur study comprehensively evaluated the appetite in obese patients underwent sleeve gastrectomy to explore the underlying mechanism.We made the hypothesis of 'Surgery-gut hormones-brain area involved in appetite-appetite performance' to explain the clinical benefits of bariatric surgery.