Progressive rise in gut hormone levels after Roux-en-Y gastric bypass suggests gut adaptation and explains altered satiety

Abstract

Background: Bariatric surgery is the most effective treatment for achieving long-term weight loss in morbidly obese patients. This study investigated prospective changes in gut hormones and metabolic indices after Roux-en-Y gastric bypass (RYGB).Methods: Six patients were seen before, and at 1, 3 and 6 months after operation. Blood was collected after a 12-h fast and at regular intervals after a mixed 420-kcal meal. Hormonal responses were determined, and comparisons between basal levels and areas under the curve were made. Visual analogue scores were used to assess satiety, hunger and nausea.Results: Mean body mass index decreased from 48·3 kg/m 2 before surgery to 36·4 kg/m 2 6 months after RYGB. This was accompanied by a decrease in fasting leptin (P < 0·001) and insulin (P = 0·021) levels. At 1, 3 and 6 months after operation, progressively increasing peptide YY (P < 0·001), enteroglucagon (P = 0·045) and glucagon-like peptide 1 (P = 0·042) responses were observed. There was no change in fasting ghrelin levels (P = 0·144). Postprandial satiety was significantly increased by 1 month after surgery and this was maintained until the end of the study (P < 0·001).Conclusion: RYGB resulted in substantial weight loss with enhanced postprandial satiety, a sustained weight plateau, and proportionate reduction in fasting insulin and leptin levels. Lack of the expected increase in appetite and food intake as components of a counter-regulatory response may be explained by gut adaptation and the consequent graded rise in the levels of gut hormones that promote satiety.

Gastric Bypass Increases Energy Expenditure in Rats

“…Body temperature in gastric bypass rats was lower than in sham-operated ad 2 libitum fed rats, but higher compared to body weight-matched sham rats during the Our data in the rat gastric bypass model are consistent with previous findings that 2 gastric bypass surgery is effective to reduce body weight and especially to maintain 3 body weight loss 4,9,10,12,16 . We confirmed that body weight loss after gastric bypass 4 was associated with a significant loss of fat mass and to a lesser degree of non-5 adipose body mass 28,29 .…”

“…We confirmed that body weight loss after gastric bypass 4 was associated with a significant loss of fat mass and to a lesser degree of non-5 adipose body mass 28,29 . Food intake was reduced in gastric bypass rats which may 6 be partly explained by hormonally mediated mechanisms 9,16,30 . Importantly, the 7 lower food intake after gastric bypass compared with sham-operated ad libitum fed 8 rats only partly explains body weight loss, because the sham-operated body weight-9 matched group required on average 40% less food than the bypass group to 10 maintain the same level of body weight.…”

Food preferences and underlying mechanisms after bariatric surgery

“…There is a body of evidence to support the gut hormones hypothesis (57,60,61) . GLP-1, peptide YY and oxyntomodulin are anorexic hormones and have been shown to reduce hunger, promote satiety and reduce food intake when given peripherally in human subjects or centrally in rodents (62)(63)(64)(65)(66) .…”

Aspectos do acompanhamento psiquiátrico de pacientes obesos sob tratamento bariátrico: revisão

“…É observado que após a cirurgia há redução importante de episódios de comer compulsivo, especialmente nos primeiros meses após o procedimento, sendo os mecanismos implicados a redução da capacidade gástrica e as alterações de neurormônios intestinais decorrentes da cirurgia (por exemplo, elevação de níveis séricos do neuropeptídio YY após RYGB, favorecendo um estado anorético) 48,75 . Entretanto, a compulsão alimentar pode ressurgir após a cirurgia, especialmente Instrumentos utilizados na avaliação diagnóstica do transtorno da compulsão alimentar periódica (TCAP):…”