Browsing by Author "CARDOSO, M.H."
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- Increase in ghrelin levels after weight loss in obese Zucker rats is prevented by gastric banding.Publication . MONTEIRO, M.P.; RIBEIRO, A.H.; NUNES, A.F.; SOUSA, M.M.; MONTEIRO, J.D.; AGUAS, A.P.; CARDOSO, M.H.Obes Surg. 2007 Dec;17(12):1599-607. Epub 2007 Nov 30. Increase in ghrelin levels after weight loss in obese Zucker rats is prevented by gastric banding. Monteiro MP, Ribeiro AH, Nunes AF, Sousa MM, Monteiro JD, Aguas AP, Cardoso MH. Department of Anatomy and UMIB (Unit for Multidisciplinary Biomedical Research) of ICBAS (Abel Salazar Institute for the Biomedical Sciences), University of Porto, 4099-003 Porto, Portugal. mpmonteiro@icbas.up.pt Abstract BACKGROUND: Gastric banding is thought to decrease appetite in addition to the mechanical effects of food restriction, although this has been difficult to demonstrate in human studies. Our aim was to investigate the changes in orexigenic signals in the obese Zucker rat after gastric banding. METHODS: Obese Zucker rats (fa/fa) were submitted to gastric banding (GBP), sham gastric banding fed ad libitum (sham), or sham operation with food restriction, pair-fed to the gastric banding group (sham-PF). Lean Zucker rats (fa/+) were used as additional controls. Body weight and food intake were daily recorded for 21 days after surgery when epididymal fat was weighed and fasting ghrelin and hypothalamic NPY mRNA expression were measured. RESULTS: Gastric banding in obese Zucker rats resulted in a significant decrease of cumulative body weight gain and food intake. Furthermore, gastric banded rats were leaner than Sham-PF, as expressed by a significantly lower epididymal fat weight. Ghrelin levels of gastric banded rats were not increased when compared to sham-operated animals fed ad libitum and were significantly lower than the levels of weight matched sham-PF rats (1116.9 +/- 103.3 g GBP vs 963.2 +/- 54.3 g sham, 3,079.5 +/- 221.6 sham-PF and 2,969.9 +/- 150.9 g lean rats, p < 0.001); hypothalamic NPY mRNA expression was not increased in GBP when compared to sham-operated rats. CONCLUSION: In obese Zucker rats, GBP prevents the increase in orexigenic signals that occur during caloric deprivation. Our data support the hypothesis that sustained weight loss observed after gastric banding does not depend solely on food restriction.
- A rat model of restrictive bariatric surgery with gastric bandingPublication . MONTEIRO, M.P.; MONTEIRO, J.D.; AGUAS, A.P.; CARDOSO, M.H.Obes Surg. 2006 Jan;16(1):48-51. A rat model of restrictive bariatric surgery with gastric banding. Monteiro MP, Monteiro JD, Aguas AP, Cardoso MH. Department of Anatomy of ICBAS (Abel Salazar Institute for the Biomedical Sciences), and Division of Endocrinology of Santo Antonio General Hospital, University of Porto, Porto, Portugal. mpmonteiro@icbas.up.pt Abstract BACKGROUND: Gastric banding is a well established weight reduction operation that is effective in the treatment of severe obesity. Its metabolic and endocrine mechanisms of action, however, remain unclear. The aim of this study was to establish a rat model of gastric banding that would replicate the procedure performed in human obese patients. METHODS: Male Wistar rats were submitted either to gastric banding (n=5) or sham gastric banding (n=4), and were followed for 21 days. Detailed description on how to perform gastric banding in rats are herein described. RESULTS: The Wistar rats submitted to gastric banding showed a decrease in weight gain and food intake when compared to sham-operated rats. The cumulative weight gain during the 21 days after the surgical procedure was 143+/-2.58 g for the gastric banded rats and 162+/-2.48 g for the sham-operated animals (P=0.001). The cumulative food intake was 329+/-0.53 g for the gastric banded rats and 380+/-15.22 g for the sham-operated animals, also statistically significant (P=0.025). CONCLUSION: A rat model to study gastric banding is described. This model can now be used for experimental investigation of biochemical and molecular mechanisms of weight loss resulting from this type of surgery. PMID: 16417758 [PubMed - indexed for MEDLINE]
- Rats submitted to gastric banding are leaner and show distinctive feeding patternsPublication . MONTEIRO, M.P.; MONTEIRO, J.D.; AGUAS, A.P.; CARDOSO, M.H.Obes Surg. 2006 May;16(5):597-602. Rats submitted to gastric banding are leaner and show distinctive feeding patterns. Monteiro MP, Monteiro JD, Aguas AP, Cardoso MH. Department of Anatomy, Unit for Multidisciplinary Biomedical Research, Abel Salazar Institute for the Biomedical Sciences, University of Porto, 4099-003 Porto, Portugal. mpmonteiro@icbas.up.pt Abstract BACKGROUND: Bariatric surgery is expanding to meet the global epidemic of morbid obesity, because this surgery is successful in achieving sustained weight loss. After having recently established a rat model of gastric banding, our aim now was to investigate the relative fat mass content and the feeding patterns of gastric banded rats. METHODS: Two groups of Wistar rats, submitted either to gastric banding or to sham surgery, were followed-up for 26 days regarding weight, daily food intake and feeding patterns both under resting conditions and when refed after fasting. Weight of the epididymal fat pad was used as a measure to evaluate changes in white adipose tissue in the rats. RESULTS: 10 days after surgery and thereafter, rats submitted to gastric banding showed the same daily food intake that was observed in sham-operated rats. Nevertheless, gastric banded rats kept lower body weights and were leaner than controls. These differences were associated with distinctive feeding patterns, both under resting conditions and when refed after fasting, suggesting that gastric banded rats present a significant increase in feeding frequency when compared with controls. CONCLUSION: This data is the first experimental evidence that an increase in feeding frequency is associated with weight loss after gastric banding, even if there is no decrease in total energy intake. Thus, medical advice on the advantages of fractionating daily caloric intake into multiple meals is further supported by the herein new information obtained in an animal model of gastric banding.