"Weight Reduction following Abdominoplasty: A Retrospective Case Review Pilot Study"
COSMETIC Weight Reduction following Abdominoplasty: A Retrospective Case Review Pilot Study Jennifer C. Fuller, M.A. Background: The question of whether or not abdominoplasty is associated with Catherine N. Nguyen, B.A. permanent weight reduction remains controversial. In coalition, should ab- Rex E. Moulton-Barrett, M.D. dominoplasty be used as an adjunct for weight reduction in the overweight/ Alameda, Los Angeles, and obese patient? San Jose, Calif. Methods: This retrospective patient case series attempts to determine the most important factors associated with weight reduction. Results: All patients undergoing abdominoplasty had weight loss beyond that of their resected pannus, with a minimum body mass index reached 11.6 1.7 weeks after surgery. Weight loss is attributed to an increase in satiety by 75 percent (n 15) of patients. Preoperative body mass index greater than or equal to 24.5 kg/m2 can be used to predict long-term weight loss with a sensitivity and specificity of 92.9 percent and 83.3 percent, respectively. Patients above this threshold achieved significantly more weight loss ( 4.5 1.4 percent body mass index) at 1 year compared with their lower body mass index counterparts (p 0.014), as did those with pannus resections weighing greater than 4.5 lb (p 0.01). Conclusions: Abdominoplasty performed on patients with a body mass index greater than 24.5 kg/m2 appears to be linked to sustained weight loss at 1 year. Satiety appears to be a prominent contributing factor, as does the amount of fat resected. Possible neurocrine mechanisms are discussed. (Plast. Reconstr. Surg. 131: 238e, 2013.) CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV. T he prevalence of obesity, defined by the Na- as it increases the risk of many diseases and health tional Institutes of Health as a body mass conditions, including but not limited to sleep index of 30 kg/m2or greater,1 has more than apnea, diabetes mellitus, hypertension, osteoar- doubled in the United States since 1980.2 Accord- thritis, dyslipidemia, certain types of cancers, ing to a recent National Health and Nutrition gallbladder disease, stroke, and coronary heart Examination Survey, a staggering 33.3 percent of disease.3 Not only is obesity associated with se- adult men and 35.3 percent of adult women in the rious comorbidities, it is also very costly. The United States are currently considered obese.2 direct health care cost of obesity is estimated to Obesity is caused by a long-term positive energy be $75 billion annually.4 balance where energy intake is greater than its Despite the growing need for therapeutic strat- expenditure. With portion sizes and consumption egies to achieve and maintain weight loss, such of high-calorie foods continuing to increase and treatments remain limited.5 Bariatric surgical pro- physical activity on the decline, it is not surprising cedures, such as gastric bypass surgery, are among that the rate of obesity continues to climb. The the few current treatments that produce perma- obesity epidemic presents a major health concern, nent weight loss.6 Despite its efficacy, surgical treatment of obesity has generally been limited to patients suffering from morbid obesity, those with From Alameda Hospital, the University of California, Los a body mass index of 40 kg/m2 or greater, as the Angeles David Geffen School of Medicine, and the University majority of these patients would gain more benefit of California, Berkeley. as compared with their overweight counterparts. Received for publication April 23, 2012; accepted August 23, 2012. Presented at the 29th Hawaii Plastic Surgery Symposium, in Honolulu, Hawaii, January 9 through 12, 2010. Disclosure: The authors have no financial interest Copyright ©2013 by the American Society of Plastic Surgeons to declare in relation to the content of this article. DOI: 10.1097/PRS.0b013e3182778649 238e www.PRSJournal.com Volume 131, Number 2 • Weight Reduction after Abdominoplasty Surgical treatment in now considered the most received thromboembolic deterrent stockings be- effective treatment for the morbidly obese fore surgery, and pneumatic compression was population.7 Most evidence points to decreased started as soon as the patients arrived in the op- morbidity and mortality as a result of the signifi- erating room and continued until discharge, 1 day cant weight loss associated with this surgery.8,9 after surgery. No prophylactic anticoagulation was Abdominoplasty is a surgical treatment available given. All patients kept thromboembolic deterrent to a greater spectrum of patients looking to decrease stockings and a firm abdominal binder on at all the size and improve the aesthetics of their midsec- times for 4 to 6 weeks after surgery and were placed tion, whether because of a large abdominal pannus on rented surgical beds with knee flexion at 25 de- resulting from massive weight loss, dermachalasis, grees or more in a jackknife sitting position at home. and prominent stria following multiple pregnancies, We encouraged our patients to eat more healthfully or because of scarring and hernia formation pro- and exercise for at least 45 minutes 3 times per week duced by previous operations.10 Whether or not starting 6 weeks after surgery. long-term weight reduction is associated with ab- In our analysis, all calculations of changes in dominoplasty has been little investigated and re- patient body mass index after abdominoplasty mains controversial.11 Possible factors implicated used the patient’s postoperative body mass index, with weight loss following abdominoplasty include calculated using the preoperative weight minus technique, premorbid weight, motivation, postop- the weight of resected pannus, as the baseline erative diet and exercise, previous bariatric surgery, body mass index. Weight loss lasting less than 1 and size of pannus resected. The purpose of the year was considered short-term weight loss, present study was to determine whether or not our whereas weight loss enduring more than 1 year was patient population was successful in obtaining a considered long-term weight loss. weight reduction after abdominoplasty, and if so, what factors were associated with maintaining long- Statistical Analysis term weight reduction. There are a variety of statistical methods used PATIENTS AND METHODS in the analysis of the patients who underwent ab- Between October of 2001 and September of dominoplasty. All statistical analyses were per- 2007, 60 patients underwent abdominoplasty per- formed in MATLAB 7.5 R2007b (The MathWorks, formed by one surgeon (R.E.M.B.). A retrospec- Inc., Natick, Mass.) with selected figures in R (R tive chart review and an in-depth patient follow-up Foundation for Statistical Computing, Vienna, interview were conducted on these patients to ob- Austria). For the comparison between preopera- tain the following information: age, height, and tive body mass index for those with and without sex of the patient; previous bariatric surgery; long-term weight loss, an unpaired two-sample t weight of the resected pannus; weight before the test was used with a significance level of 0.05. abdominoplasty and chronologically after surgery; Where appropriate, one-way analysis of variance satiety following surgery; satisfaction with abdomi- was used. All results are given using mean SEM. noplasty results; and postsurgery lifestyle, includ- To aid in the determination of a clinical threshold, ing diet, exercise regimen, and personal beliefs as receiver operating characteristic curve analysis was to the cause of weight loss. used to evaluate the performance of preoperative Of the original 60 patients, 39 could not be body mass index to predict long-term weight loss contacted for the follow-up interview and thus and to determine a threshold for the size of the were excluded from the results of this study. An pannus. All correlations were performed using additional patient was excluded from analysis be- Pearson correlation and, finally, the Fisher’s exact cause of pregnancy in the postoperative year. Of test was used to statistically compare the subjective the remaining 20 patients—all women—five had responses of the patients. previously undergone bariatric surgery but were included in our results. The 20 patients ranged RESULTS in age from 26 to 61 years, with a mean SD of 45.1 Follow-up interviews and charted information 10.4 years. were obtained on 20 patients, with an average The surgical technique used involved pannus follow-up time of 29 months (range, 15 to 54 resection in the jackknife, 90-degree-flexed posi- months). Preoperative mean SEM body mass tion, which was preceded by a tight two-layer per- index was 27.645 1.0 kg/m2, and the weight of manent suture rectus anterior fascia plication the resected pannus was 5.215 0.7 lb. Of the 20 from the xiphoid to the pubic bone. All patients patients, 14 (70 percent) had sustained weight loss 239e Plastic and Reconstructive Surgery • February 2013 beyond postoperative weight (preoperative minus time to maximum weight loss for the short- and pannus) at 1 year. The remaining six (30 percent) long-term weight loss groups. The long-term patients experienced some degree of weight loss weight loss group had a significantly higher pre- following surgery; however, they exceeded their operative and postoperative body mass index postoperative body mass index at the 1-year follow- and greater maximum change in body mass in- up. Of the patients with long-term weight loss, the dex when compared with the short-term weight preoperative body mass index was 29.7 0.9 loss group (Fig. 2). The time to maximum kg/m2 versus 22.9 1.2 kg/m2. Based on receiver weight loss did not reach significance. operating characteristic curve analysis, the high When patients were asked for the most impor- sensitivity and specificity cutoff point for long- tant factors contributing to their weight loss, 75.0 term weight loss is at a preoperative body mass percent (n 15) reported an increased feeling of index of 24.5 kg/m2, with a sensitivity of 92.9 per- satiety, either with eating or generally throughout cent, a specificity of 83.3 percent, and an accuracy the day. When asked what led to the weight loss, of 90 percent. Based on this threshold, patients only one (5 percent) attributed it to diet alone; with a preoperative body mass index greater than eight (40 percent) to satiety alone; five (25 per- or equal to 24.5 kg/m2 have a significantly (p cent) to a combination of diet, exercise, and/or 0.014) greater decrease in body mass index be- satiety; three (15 percent) to their previous gastric yond pannus weight at 1 year compared with those bypass; and the remaining three (15 percent) to at or below this threshold (an average change in other reasons. Of those experiencing satiety, 60 body mass index at 1 year of 4.5 1.4 percent percent (n 9) retained that sensation at 1 year, versus 2.0 1.7 percent). Of patients with a body whereas in the other 40 percent (n 6) it lasted mass index above 24.5 kg/m2, 92.8 percent (n an average of 3.9 months. For the long-term 13) had long-term weight loss at 1 year as com- weight loss group specifically, 85.7 percent (n pared with 16.7 percent (n 1) of patients below 12) reported a change in satiety (seven had early this threshold. satiety with eating only and five had a general The trends of the short- and long-term weight feeling of fullness at all times). For the short-term loss groups are shown for preoperative body mass weight loss group, 50.0 percent (n 3) reported index, postoperative body mass index, minimum an increase in satiety, with a majority of those body mass index, and 1-year body mass index in Figure 1. The short- and long-term data are sig- having a general sense of satiety throughout the nificantly different for all four time points (p day. A complete description for the degree of sa- 0.001, p 0.001, p 0.01, and p 0.024, respec- tiety is shown in Table 2. Using the Fisher’s exact tively). Table 1 shows postoperative body mass test, no significant relationship was found between index, maximum change in body mass index, and the short- and long-term weight loss groups (p 0.17) with respect to satiety. We also wondered whether the size/weight of the pannus might be directly associated with long- term weight reduction. Using receiver operating characteristic curve analysis, the optimal thresh- old for differentiating the short- and long-term weight loss groups produced a pannus size of 4.5 lb, with a respective sensitivity and specificity of 85.7 and 100 percent. Based on this threshold, eight patients had an excised pannus under 4.5 lb, and the remaining 12 patients had a pannus greater than 4.5 lb. The preoperative body mass index was significantly higher in the larger pannus group (p 0.001), which is reinforced by the significant positive correlation between pannus size and preoperative body mass index (p 0.001). Both the maximum change in body mass Fig. 1. Average patient body mass index (BMI) preoperatively index and the change in body mass index at 1 year and postoperatively, minimum body mass index, and body mass were not significantly different between the two index at 1 year for the long- and short-term weight loss groups. pannus groups. The complete data are listed in SEM bars are shown at each of the measurement times. Table 3. 240e Volume 131, Number 2 • Weight Reduction after Abdominoplasty Table 1. Change from Postoperative Body Mass Index with Respect to Short- and Long-Term Weight Loss Groups* No. of Postoperative Maximum Change Time of Maximum Change in BMI Patients (%) BMI (kg/m2) in BMI (%) Weight Loss (wk) at 1 Yr (%) Short-term weight loss 6 (30%) 22.5 1.1 3.6 0.8 7.1 1.3 3.2 1.3 Long-term weight loss 14 (70%) 28.6 0.9 8.8 1.4 13.4 2.0 5.0 1.2 p N/A 0.001 0.032 0.093 0.001 BMI, body mass index; N/A, not applicable. *SEM and significance are provided. Finally, Table 4 shows the relationship in pannus size, maximum change in body mass index, change in body mass index at 1 year, time to maximum change, and number of patients with long-term weight loss for three standard body mass index cat- egories (normal to underweight, 25 kg/m2; over- weight, 25 to 30 kg/m2; and obese, 30 kg/m2). Using one-way analysis of variance, the pannus weights between the normal weight group (body mass index 25) and the obese group (body mass index 30) are significantly different. The relation- ship in maximum change in body mass index and 1-year change in body mass index among these Fig. 2. Violin plots for preoperative body mass index (BMI) in groups is shown in Figure 3. short- and long-term weight loss groups. Table 2. Satiety in Short- and Long-Term Weight Loss Groups No. of No Change in Sense of Satiety Sense of Satiety Patients Appetite (%) Only with Eating (%) Throughout the Day (%) Short-term weight loss 6 3 (50.0) 1 (16.6) 2 (33.3) Long-term weight loss 14 2 (14.3) 7 (50.0) 5 (35.7) All patients 20 5 (25.0) 8 (40.0) 7 (35.0) Table 3. Changes in Body Mass Index as a Function of Resected Pannus Weight* Weight of No. of Preoperative Maximum Change Change in BMI No. with Long-Term Pannus Patients (%) BMI (kg/m2) in BMI (%) at 1 Yr (%) Weight Loss 4.5 lb 8 (40) 23.4 0.9 4.3 0.8 1.1 1.7 2 4.5 lb 12 (60) 30.5 0.9 9.2 1.6 4.9 1.4 12 p N/A 0.001 0.029 0.01 N/A BMI, body mass index; N/A, not applicable. *SEM and significance are provided. Table 4. Statistics with Respect to Patient Body Mass Index Categories: Normal Weight, Overweight, and Obese* Time to Reach No. of Patients Preoperative No. of Pannus Maximum 1-Yr Change Maximum Weight with Weight BMI (kg/m2) Patients (%) Weight (lb) Change in BMI (%) in BMI (%) Loss (wk) Loss at 1 Yr (%) 25 7 (35) 3.2 1.0 4.7 1.0 0.7 1.9 12.2 3.6 2 (28.6) 25–30 7 (35) 4.7 0.6 8.4 1.8 4.7 2.4 13.1 2.8 6 (85.7) 30 6 (30) 8.1 1.4 8.8 2.8 3.7 1.8 8.8 0.9 6 (100) p N/A 0.01 0.28 0.17 0.59 N/A BMI, body mass index; N/A, not applicable. *Statistics with respect to patient normal weight, overweight, and obese BMI categories. SEM and analysis of variance significance are provided. 241e Plastic and Reconstructive Surgery • February 2013 Fig. 3. Percentage change in body mass index (BMI) at minimum body mass index and 1-year time points for patients with a body mass index less than 24.5 kg/m2 and greater than or equal to 24.5 kg/m2. The black bars represent the maximum percentage change in body mass index over the 1-year follow-up period, whereas the lighter bars represents the change from the postoperative body mass index at 1 year. SEM bars are shown. DISCUSSION percent of their postoperative body weight as com- The current retrospective study found that all pared with a loss of 4.5 1.5 percent in those with patients undergoing abdominoplasty had some body mass indexes above 24.5 kg/m2 (p 0.014). degree of weight loss beyond that of their resected This tells us that overweight and obese patients pannus. Of these patients, 70 percent (n 14) tend to have more long-term weight reduction maintained weight loss at 1 year. The most com- benefit from abdominoplasty than their normal- monly reported factor attributed to this weight weight counterparts. Although this may be be- loss is a sense of satiety, found in 75 percent (n cause normal weight patients have less body fat to 15) of patients, either as general satiety through- lose, it is possible that a change in neuroendocrine out the day or early satiety with eating. The ma- factors as discussed below affects overweight and jority [n 9 (60 percent)] of patients experienc- obese patients to a greater extent. ing satiety maintained that sensation at 1 year, Another factor significantly correlated with whereas in others it lasted an average of 15.7 2.8 long-term weight loss is the weight of the resected weeks. It is possible that a loss or decrease in satiety pannus. Patients with pannus resections weighing contributes to weight regain, as all patients re- greater than 4.5 lb had significantly greater gained some weight after reaching their nadir changes in body mass index at minimum and around this same time (11.6 1.7 weeks). Al- 1-year time points (p 0.029 and p 0.01, re- though there was a trend toward patients with spectively) compared with those with smaller re- satiety achieving more long-term weight loss, this sections. Although the weight of the resected pan- did not reach statistical significance (p 0.17). nus is logically dependent on patient body mass When trying to determine what other factors index and the correlation with long-term weight are associated with long-term weight loss, we loss may simply be a product of body mass index found that patient preoperative body mass index effect, it must also be considered that the greater was significantly correlated, with those weighing the amount of fat cells removed, the greater the greater than or equal to 24.5 kg/m2 achieving impact on the neuroendocrine milieu regulating long-term weight loss with a sensitivity and speci- satiety and weight balance, as discussed below. In ficity of 92.9 and 83.3 percent, respectively. Of particular, the possibility that removing fat cells patients with a preoperative body mass index that produce leptin may reduce leptin resistance greater than or equal to 24.5 kg/m2, 92.8 percent has been described in the obese patient.12 (n 13) maintained long-term weight loss at 1 We hypothesize that the increased satiety seen year as compared with 16.6 percent (n 1) of in our patients and subsequent weight loss is re- those below this threshold. At 1 year, patients be- lated to changes in the neuroendocrine system. low this threshold gained an average of 2.0 1.7 This is supported by the latest studies on appetite that 242e Volume 131, Number 2 • Weight Reduction after Abdominoplasty have found that food intake is regulated by the change in gastrointestinal peptide hormone or action of gastrointestinal peptide hormones and leptin expression. This will elucidate the satiety leptins, hormones secreted from adipose tissue, signals that are responsible for the loss of appetite on the central nervous system. These hormones found in our patients. Further studies will clarify act as satiety signals in the vagal-brainstem-hypo- the mechanisms of appetite regulation and may thalamic pathway.13 In the hypothalamus, gut hor- lead to the creation of an injectable appetite sup- mones and leptins act by stimulating/inhibiting pressant drug. With the increasing global preva- neurons in the arcuate nucleus of the hypothala- lence of obesity and its ensuing physiologic, psy- mus. In turn, this control center responds by ex- chological, and economic implications, the need pressing peptides that either stimulate or inhibit to understand appetite control is imperative. food intake.13–16 Afferent signals from the vagus Rex E. Moulton-Barrett, M.D. nerve convey information about the mechanical 2070 Clinton Avenue and chemical stimulation of the gastrointestinal Alameda, Calif. 95401 tract by ingested food to the brainstem. This fur- email@example.com ther elicits reflexes that control gastrointestinal functions and sends signals to the hypothalamus REFERENCES to inhibit food intake.16,17 The vagus nerve con- 1. National Institutes of Health, National Heart, Lung, and tains mechanoreceptors that are sensitive to stom- Blood Institute. Clinical Guidelines on the Identification, Eval- ach and intestinal volume and luminal pressure uation, and Treatment of Overweight and Obesity in Adults: The and receptors for a number of gut hormones. This Evidence Report . Washington, DC: U.S. Department of Health then conveys information about the ingested and Human Services, Public Health Service, National Insti- food.16,18 –21 Studies have shown that vagotomy tutes of Health, National Heart, Lung, and Blood Institute; 1998. abolishes the appetite-modifying actions of these 2. Ogden CL, Carroll MD, McDowell MA, Flegal KM. Obesity gut hormones.20,22–24 among adults in the United States: No statistically significant Many gastrointestinal peptide hormones and change since 2003–2004. NCHS Data Brief 2007;1:1–8. leptins have been discovered. They are known to 3. Pi-Sunyer FX. Comorbidities of overweight and obesity: Cur- inhibit/stimulate food intake by acting at the rent evidence and research issues. Med Sci Sports Exerc. 1999; 31:S602–S608. vagus nerve and/or the arcuate nucleus. For 4. Finkelstein EA, Fiebelkorn IC, Wang G. National medical example, leptin, which is released from adipose spending attributable to overweight and obesity: How much, tissue, and insulin, which is secreted by the pan- and who’s paying? Health Affairs (Millwood) 2003;Suppl Web creas, both function within the hypothalamus to Exclusives:W3-219–W3-226. inhibit food intake.15,25,26 Cholecystokinin, in 5. Bray GA, Tartaglia LA. Medicinal strategies in the treatment of obesity. Nature 2000;404:672–677. contrast, is secreted by the I cells of the small ¨ ¨ 6. Sjostrom L. Surgical intervention as a strategy for treatment intestine and acts mainly through the vagus nerve of obesity. Endocrine 2000;13:213–230. to inhibit feeding by modifying gastrointestinal 7. Livingston EH. Obesity, mortality, and bariatric surgery tract functions.15,20,27,28 Peptide YY, oxyntomodu- death rates. JAMA 2007;298:2406–2408. lin, and glucagon-like peptide-1 are all secreted 8. Buchwald H, Avidor Y, Braunwald E, et al. Bariatric surgery: A systemic review and meta-analysis. JAMA 2004;292:1724– from L cells in the intestines. They act on both the 1728. hypothalamus and the vagus nerve to inhibit food 9. Christou NV, Sampalis JS, Liberman M, et al. Surgery de- intake.15,28,29,30 Pancreatic peptide, released from creases long-term mortality, morbidity, and health care use the pancreas; glucose-dependent insulinotropic in morbidly obese patients. Ann Surg. 2004;240:416–423; dis- polypeptide, secreted from the stomach, duode- cussion 423–424. 10. Savage RC. Abdominoplasty following gastrointestinal bypass num, and jejunum; adiponectin, produced by ad- surgery. Plast Reconstr Surg. 1983;71:500–509. ipose tissue; and amylin, from the pancreas, are 11. Shermak MA, Bluebond-Langner R, Chang D. Maintenance other satiety-promoting gut hormones.13,15,16 So of weight loss after body contouring surgery for massive far, ghrelin, which is produced in the stomach, is weight loss. Plast Reconstr Surg. 2008;121:2114–2119. the only known circulating appetite stimulant. It 12. El-Haschimi K, Lehnert H. Leptin-resistance— or why leptin fails to work in obesity. Exp Clin Endocrinol Diabetes 2003;111: functions at the hypothalamic level.13,15,16 2–7. This is a pilot study, and with future studies, we 13. Chaudhri OB, Salem V, Murphy KG, Bloom SR. Gastroin- would propose measuring levels of these gastro- testinal satiety signals. Annu Rev Physiol. 2008;70:239–255. intestinal peptide hormones before our patients 14. Cone RD, Cowley MA, Butler AA, Fan W, Marks DL, Low MJ. undergo abdominoplasty and then at incremental The arcuate nucleus as a conduit for diverse signals relevant to energy homeostasis. Int J Obes Relat Metab Disord. 2001;25: times after surgery. By comparing hormone levels S63–S67. before and after abdominoplasty, we will be able 15. Austin J, Marks D. Hormonal regulators of appetite. Int J Pe- to determine whether there is any significant diatr Endocrinol. 2009;2009:141753. 243e Plastic and Reconstructive Surgery • February 2013 16. Strader AD, Woods SC. Gastrointestinal hormones and food 23. Koda S, Date Y, Murakami N, et al. The role of the vagal nerve intake. Gastroenterology 2005;128:175–191. in peripheral PYY3-36-induced feeding reduction in rats. 17. Moran TH, Ladenheim EE, Schwartz GJ. Within-meal gut Endocrinology 2005;146:2369–2375. feedback signaling. Int J Obes Relat Metab Dis. 2001;25(Suppl 24. Asakawa A, Inui A, Yusuriha H, et al. Characterization of the 5):S39–S41. effects of pancreatic polypeptide in the regulation of energy 18. Berthoud HR. Multiple neural systems controlling food in- balance. Gastroenterology 2003;124:1325–1336. take and body weight. Neurosci Biobehav Rev. 2002;26:393– 25. Elias CF, Aschkenasi C, Lee C, et al. Leptin differentially 428. regulates NPY and POMC neurons projecting to the lateral 19. Powley TL, Phillips RJ. Musings on the wanderer: What’s new hypothalamic area. Neuron 1999;23:775–786. in our understanding of vago-vagal reflexes? I. Morphology 26. Cheatham B, Kahn CR. Insulin action and the insulin sig- and topography of vagal afferents innervating the GI tract. naling network. Endocr Rev. 1995;16:117–142. Am J Physiol Gastrointest Liver Physiol. 2002;283:G1217–G1225. 27. Druce M, Bloom SR. The regulation of appetite. Arch Dis 20. Moran TH, Kinzig KP. Gastrointestinal satiety signals II. Cho- Child. 2006;91:183–187. lecystokinin. Am J Physiol Gastrointest Liver Physiol. 2004;286: G183–G188. 28. D’Alessio D. Intestinal hormones and regulation of satiety: 21. Date Y, Murakami N, Toshinai K, et al. The role of the gastric The case for CCK, GLP-1, PYY, and Apo A-IV. JPEN J Parenter afferent vagal nerve in ghrelin-induced feeding and growth Enteral Nutr. 2008;32:567–568. hormone secretion in rats. Gastroenterology 2002;123:1120– 29. Batterham RL, Cowley MA, Small CJ, et al. Gut hormone 1128. PYY(3-36) physiologically inhibits food intake. Nature 2002; 22. Abbott CR, Monteiro M, Small CJ, et al. The inhibitory effects 418:650–654. of peripheral administration of peptide YY(3-36) and gluca- 30. Baggio LL, Huang Q, Brown TJ, Drucker DJ. Oxyntomodulin gon-like peptide-1 on food intake are attenuated by ablation and glucagon-like peptide-1 differentially regulate murine of the vagal-brainstem-hypothalamic pathway. Brain Res. food intake and energy expenditure. Gastroenterology 2004; 2005;1044:127–131. 127:546–558. 244e