Different Effect of Laparoscopic Roux-en-Y Gastric Bypass and Open Biliopancreatic Diversion of Scopinaro on Serum PYY and Ghrelin Levels

Background  The impact of bariatric surgery on levels of peptide YY (PYY) and ghrelin is still under discussion. We undertook a simultaneous evaluation of the serum changes in PYY and ghrelin depending on the specific type of bariatric surgery. Methods  Total PYY and ghrelin were analyzed in 29 healthy persons and in morbidly obese persons undergoing open biliopancreatic diversion (BPD) of Scopinaro (n = 38) or laparoscopic Roux-en-Y gastric bypass (RYGB; n = 13). Results  RYGB resulted in a significantly greater loss of weight and body mass index than BPD. Both RYGB and BPD were associated with a significant increase in PYY, significantly greater for BDP (p = 0.001). Ghrelin rose significantly after RYGB (p = 0.022) but not after BPD. After surgery, PYY correlated positively with weight (r = 0.416, p = 0.009). Ghrelin did not correlate significantly with any of the variables studied. Analysis of variance showed that only the type of surgery contributed significantly to explain the variances in the PYY (p = 0.002) and ghrelin (p = 0.018). Conclusions  BPD results in a greater increase in PYY and a lower weight loss than RYGB. However, only RYGB was associated with a significant increase in ghrelin. The differing weight loss according to the type of bariatric surgery does not seem to be explained by changes arising in PYY and ghrelin.     

Peptide YY and Glucagon-like Peptide-1 in Morbidly Obese Patients Before and After Surgically Induced Weight Loss

Background Peptide YY (PYY) and glucagon-like peptide-1 (GLP-1) are cosecreted in the same enteroendocrine L-cells of the gut and reported to inhibit food intake additively. However, findings in human studies regarding these peptides are controversial. The aim of this study was to analyze the relationships between fasting PYY, GLP-1, and weight status in morbidly obese patients before and after surgically induced weight loss. Methods Fasting GLP-1, PYY, glucose, and insulin concentrations; blood pressure; and body-mass index (BMI) were determined in 30 morbidly obese adults (mean BMI 45.8, mean age 40 years) before bariatric surgery [Roux-en-Y gastric bypass (RYGB): n = 19; gastric banding (GB): n = 11] and after weight loss (mean 50% excess weight loss) in the course of mean 2 years. Results GLP-1 concentrations decreased (mean −20 pg/ml; mean −38%; p = 0.001) and PYY concentrations increased (mean +19 pg/ml; mean +19%, p = 0.036) after bariatric surgery. The weight loss and changes of GLP-1 were significantly (p < 0.05) more pronounced after RYGB as compared to GB, whereas the changes of PYY did not differ significantly between the patients who had undergone RYGB or GB. Conclusions In morbidly obese adults reducing their weight by bariatric surgery, fasting PYY levels increased and GLP-1 concentrations decreased independently of each other. Therefore, the relationship between PYY and GLP-1 seems more complicated than might be anticipated from animal and in vitro studies. T. Reinehr and C. L. Roth contributed equally to this work.     

The Serial Changes of Ghrelin and Leptin Levels and Their Relations to Weight Loss After Laparoscopic Minigastric Bypass Surgery

Background The ghrelin and leptin levels have been reported to be correlated with weight loss after bariatric surgery. However, the serial changes of ghrelin and leptin levels after laparoscopic minigastric bypass surgery (LMGBP) have not been reported yet. Therefore, we aimed to evaluate their serial changes and to analyze their relations to weight reduction after LMGBP. Methods Serial fasting serum leptin and ghrelin concentrations were measured in 68 morbidly obese patients before (M0) and 1 (M1), 3 (M3), 6 (M6), and 12 (M12) months after LMGBP surgery. The correlations between ghrelin, insulin, and leptin concentrations and weight reduction were analyzed. Results Leptin levels were significantly reduced at 1, 3, 6, and 12 months after surgery, respectively (vs M0, p < 0.001), whereas the ghrelin concentrations were not significantly changed after surgery. The percent of excess BMI lost (%EBL) 12 months after surgery was negatively correlated with higher preoperative ghrelin concentrations (p = 0.004) and larger preoperative BMI (p = 0.002) in the multivariate analysis. Conclusion Higher preoperative ghrelin concentrations and larger BMI are predictive of less %EBL at 12 months after LMGBP surgery.     

Serum Magnesium Status After Gastric Bypass Surgery in Obesity

Background  Roux-en-Y gastric bypass (RYGBP) has become a common surgical procedure to treat morbid obesity. Furthermore, it strongly reduces the incidence of type 2 diabetes and mortality. However, there is scant information on how magnesium status is affected by RYGBP surgery. Previous bariatric surgery methods, like jejunoileal bypass, are associated with hypomagnesemia. Methods  Twenty-one non-diabetic morbidly obese patients who underwent RYGBP were evaluated before and 1 year after surgery and compared to a matched morbidly obese control group regarding serum magnesium. Groups were matched regarding weight, BMI, abdominal sagittal diameter and fasting glucose, blood pressure, and serum magnesium concentrations before surgery in the RYGBP group. Results  The serum magnesium concentrations increased by 6% from 0.80 to 0.85 mmol/l (p = 0.019) in the RYGBP group while a decrease by 4% (p = 0.132) was observed in the control group. The increase in magnesium concentration at the 1-year follow-up in the RYGBP group was accompanied by a decreased abdominal sagittal diameter (r ² = 0.32, p = 0.009), a lowered BMI (r ² = 0.28, p = 0.0214), a lowered glucose concentration (r ² = 0.28, p = 0.027) but not by a lowered insulin concentration (p = 0.242), a lowered systolic (p = 0.789) or a lowered diastolic (p = 0.785) blood pressure. Conclusion  RYGBP surgery in morbidly obese subjects is characterized by reduced visceral adiposity, lowered plasma glucose, and increased circulating magnesium concentrations. The inverse association between lowered central obesity, lowered plasma glucose and increased magnesium concentrations, needs further detailed studies to identify underlying mechanisms.     

Persistent Correlation of Ghrelin Plasma Levels with Body Mass Index Both in Stable Weight Conditions and during Gastric-bypass-induced Weight Loss

Background  Studies done on serial changes in plasma ghrelin levels after gastric bypass (GBP) have yielded contrasting results since decreased, unchanged, or increased levels have been reported in the literature. This study investigates whether or not GBP has an inhibitory effect on fasting ghrelin levels independently of weight loss. Methods  Fasting ghrelin levels were measured in 115 stable body weight females, classified as normal body weight (NW; body mass index (BMI) < 25 kg/m²), overweight (OW; BMI 25–30 kg/m²), and obese subjects, divided in three subgroups with increasing BMI (BMI 30–40 kg/m²; BMI 40–50 kg/m²; BMI >50 kg/m²). Results  Each obese subgroup showed significantly lower ghrelin levels as compared to both NW (p < 0.0001) and OW subjects (p < 0.05 or 0.005); however, no significant differences were observed within the three obese subgroups. Forty-nine obese patients underwent a GBP. Plasma ghrelin, measured at 3, 6, and 12 months after GBP, significantly increased from the sixth month on (p < 0.0001). When patients were classified, at each postoperative time point, according to their actual BMI, ghrelin was significantly (p = 0.0002) related to postoperative BMI and not significantly different from ghrelin measured in stable body weight conditions. Conclusions  Fasting ghrelin displays an inversely significant correlation with BMI in both stable body weight conditions and after GBP. No evidence was found that GBP had an effect on fasting ghrelin levels, independent of weight loss.     

Relation Between Carbohydrate Intake and Weight Loss After Bariatric Surgery

Background  Weight loss and long-term weight maintenance in bariatric surgery patients are related to maintaining satiety. It can be related to glycemic load (GL) and carbohydrate (g CHO) intake. The aim of this study was to investigate the effect of g CHO and GL and in weight loss on patients who had undergone bariatric surgery. Method  The following measurements/calculations were conducted as follows: current body weight (kg), current BMI, percentage of excess weight loss (PEWL), average monthly weight loss (AMWL), energy intake (kcal per day), and GL calculation. Correlations were found among the studied variables. A multiple linear regression analysis of diet variables executed with GL and weight loss. Results  The population presented 66% of EWL. The average of total energy intake (TEI) was 1220 ± 480, and the calculated GL resulted in an average of 73.2. Negative correlations were found between AMWL and TEI (p = 0.04), and between AMWL and GL (p = 0.009); furthermore, a negative correlation was found between carbohydrate intake in grams and AMWL (p = 0.003). A positive correlation (p = 0.017) was found between GL and TEI. Weight loss and GL were also correlated. Among the intake variables, GL and g CHO consumed are held accountable for 62 percent of AMWL. The multiple linear regression analysis showed that GL and carbohydrate grams (g CHO) account for 62% of AMWL. Conclusion  The glycemic load and grams of carbohydrate are intake factors that can be useful tools in weight loss and long-term weight maintenance on patients who have undergone Roux-en-Y Gastric Bypass (RYGB).     

Effect of Roux-en Y Gastric Bypass on Bone Metabolism in Patients with Morbid Obesity: Mansoura Experiences

Background  Roux-en-Y gastric bypass (RYGBP) has been found to be the most efficient way to lose weight and maintain the weight loss in morbid obesity. However, with the formation of a new stomach and the modification of intestinal anatomy, there are significant changes on bone metabolism. The objectives of this study were to evaluate effects of weight loss on bone metabolism after Roux-en Y gastric bypass in patients with morbid obesity. Methods  Our study included 70 patients with morbid obesity; RYGB was done for all patients. Daily postoperative oral supplementation with 1,000 mg of calcium and 800 IU of vitamin D was done for each patient. Body weight (BW), body mass index (BMI), total body fat, total lean tissue mass, bone mineral content (BMC), bone mineral density (BMD), total bone area (TBA; using dual energy X-ray absorptiometry), serum calcium, parathyroid hormone (PTH), 25-OH vitamin D, 24-h urinary calcium, and bone-specific alkaline phosphatase (BSAP) were assessed preoperatively and 1 year after surgery. Results  In our study, females comprised 70% of cases. The mean age was 35 ± 8.8 years. One year after RYGB, BW decreased significantly from 132.8 ± 26.5 to 90.3 ± 17.3 kg (p = 0.001). BMI decreased significantly from 48 ± 7.3 to 32.6 ± 4.1 kg/m² (p = 0.001). BMC decreased significantly from 2,968.6 ± 71.4 to 2,700.8 ± 45.4 g (p = 0.001). BMD decreased significantly from 1.026 ± 0.03 to 1.22 ± 0.015 g/cm² (p = 0.001). TBA decreased significantly from 2,356.2 ± 35.4 to 2,216.3 ± 43.5 cm² (p = 0.001). Serum calcium, 24-h urinary calcium, and BSAP were not significantly decreased while 25-OH vitamin D and PTH were not significantly increased after surgery. Conclusions  From this study, it is shown that RYGBP operation gives very good results as regards reduction of body weight in morbidly obese patients. Postoperative supplementation with calcium and vitamin D partially corrects osteoporosis. Thus, these patients need periodic follow-up for BMD, PTH, calcium, serum vitamin D, and markers of bone resorption and formation specially postmenopausal female.     

Alterations in Proinsulin and Insulin Dynamics, HDL Cholesterol and ALT After Gastric Bypass Surgery. A 42-Months Follow-up Study

Background  Roux-en-Y gastric bypass (RYGBP) powerfully reduces type 2 diabetes (T2DM) incidence. Proinsulin predicts development of T2DM. Adjustable gastric banding is associated with lowered proinsulin but after RYGBP information is scant. Methods  Twenty-one non-diabetic morbidly obese patients who underwent RYGBP surgery were evaluated before (baseline), at 12 months (first follow-up), and at 42 months, range 36–50 (second follow-up), after surgery and compared to a control group, matched at baseline regarding fasting glucose, insulin, proinsulin, alanine aminotransferase (ALT), high-density lipoprotein (HDL) cholesterol, and body mass index (BMI). Results  In the RYGBP group, fasting serum proinsulin concentrations were markedly lowered from 13.5 to 3.5 pmol/l at first follow-up and to 4.9 pmol/l at second follow-up (p < 0.001, respectively). Fasting insulin concentrations were reduced from 83.4 to 24.6 pmol/l at first follow-up (p < 0.001) and to 36.4 pmol/l at second follow-up (p < 0.01). ALT was lowered from 0.62 to 0.34 μkatal/l at first follow-up and continued to lower to 0.24 μkatal/l at second follow-up (p < 0.001, respectively). The further decrease between first and second follow-up was also significant (p = 0.002). HDL cholesterol increased from 1.16 to 1.45 mmol/l at the first follow-up and continued to increase at second follow-up to 1.58 mmol/l (p < 0.001, respectively). The further increase between first and second follow-up was also significant (p = 0.006). The differences between groups at first follow-up were significant for BMI, proinsulin, insulin, ALT, and HDL cholesterol (p = 0.04–0.001). Conclusion  RYGBP surgery in morbidly obese patients is not only characterized by markedly and sustained lowered BMI but also lowered concentrations of proinsulin, insulin, and ALT and increased HDL cholesterol. An erratum to this article can be found at     

Lipoprotein Lipase but Not Hormone-Sensitive Lipase Activities Achieve Normality After Surgically Induced Weight Loss in Morbidly Obese Patients

Background  Although bariatric surgery is currently the most common practice for inducing weight loss in morbidly obese patients (BMI > 40 kg/m²), its effect on the lipid content of adipose tissue and its lipases (lipoprotein lipase [LPL] and hormone-sensitive lipase [HSL]) are controversial. Methods  We analyzed LPL and HSL activities and lipid content from plasma as well as subcutaneous (SAT) and visceral (VAT) adipose tissue of 34 morbidly obese patients (MO) before and after (6 and 12 months) Roux-en-Y gastric bypass surgery and compare the values with those of normal weight (control) patients. Results  LPL activity was significantly higher in MO (SAT = 32.9 ± 1.0 vs VAT = 36.4 ± 3.3 mU/g tissue; p < 0.001) than in control subjects (SAT = 8.2 ± 1.4 vs VAT = 6.8 ± 1.0 mU/g tissue) in both adipose depots. HSL activity had similar values in both types of tissue (SAT = 32.8 ± 1.6 and VAT = 32.9 ± 1.6 mU/g) of MO. In the control group, we found similar results but with lower values (SAT = 11.9 ± 1.4 vs VAT = 12.1 ± 1.4 mU/g tissue). Twelve months after surgery, SAT LPL activity diminished (9.8 ± 1.4 mU/g tissue, p < 0.001 vs morbidly obese), while HSL (46.6 ± 3.7 mU/g tissue) remained high. All lipids in tissue and plasma diminished after bariatric surgery except plasma nonesterified fatty acids, which maintained higher levels than controls (16 ± 3 vs 9 ± 0 mg/dL; p < 0.001, respectively). Conclusions  When obese patients lose weight, they lose not only part of the lipid content of the cells but also the capacity to store triacylglycerides in SAT depots. E. Pardina and A. Lecube contributed equally to this study. J.A. Baena-Fustegueras and J. Peinado-Onsurbe share senior authorship.     

Revisional vs. Primary Roux-en-Y Gastric Bypass—a Case-matched Analysis

With the increase in bariatric procedures performed, revisional surgery is now required more frequently. Roux-en-Y gastric bypass (RYGB) is considered to be the gold standard revision procedure. However, data comparing revisional vs. primary RYGB is scarce, and no study has compared non-resectional primary and revisional RYGB in a matched control setting. Analysis of 61 revisional RYGB that were matched one to one with 61 primary RYGB was done. Matching criteria were preoperative body mass index, age, gender, comorbidities and choice of technique (laparoscopic vs. open). After matching, the groups did not differ significantly. Previous bariatric procedures were 13 gastric bands, 36 vertical banded gastroplasties, 10 RYGB and two sleeve gastrectomies. The indication for revisional surgery was insufficient weight loss in 55 and reflux in 6. Intraoperative and surgical morbidity was not different, but medical morbidity was significantly higher in revisional procedures (9.8% vs. 0%, p = 0.031). Patients undergoing revisional RYGB lost less weight in the first two postoperative years compared with patients with primary RYGB (1 month, 14.9% vs. 29.7%, p = 0.004; 3 months, 27.4% vs. 51.9%, p = 0.002; 6 months, 39.4 vs. 70.4%, p < 0.001; 12 months, 58.5% vs. 85.9%, p < 0.001; 24 months, 60.7% vs. 90.0%, p = 0.003). Although revisional RYGB is safe and effective, excess weight loss after revisional RYGB is significantly less than following primary RYGB surgery. Weight loss plateaus after 12 months follow-up.     

Revision of Failed Bariatric Procedures to Roux-en-Y Gastric Bypass (RYGB)

Bariatric surgery for morbid obesity has been established as an effective treatment method and has been shown to be associated with resolution of co-morbidities. Despite its success, some patients may require revision because of weight regain or mechanical complications. From September 2005 to December 2009, 42 patients underwent revisional Roux-en-Y gastric bypass (RYGB). All procedures were performed by one surgeon. Demographics, indications for revision, complications, and weight loss were reviewed. Thirty-seven patients were treated with laparoscopic (n = 36) or open (n = 1) RYGB after failed laparoscopic adjustable gastric banding. Four patient were treated with laparoscopic (n = 3) or open (n-1) RYGB after failed vertical banded gastroplasty, and one patient underwent open redo RYGB due to large gastric pouch. Conversion rate from laparoscopy to open surgery was 2.5% (one patient). Mean operative time was 145.83 ± 35.19 min, and hospital stay was 3.36 ± 1.20 days. There was no mortality. Early and late complications occurred in six patients (14.2%). The mean follow-up was 15.83 ± 13.43 months. Mean preoperative body mass index was 45.15 ± 7.95 that decreased to 35.23 ± 6.7, and mean percentage excess weight loss was 41.19 ± 20.22 after RYGB within our follow-up period. RYGB as a revisional bariatric procedure is effective to treat complications of restrictive procedures and to further reduce weight in morbidly obese patients.     

Impact of Sustained Weight Loss Achieved through Roux-en-Y Gastric Bypass or a Lifestyle Intervention on Ghrelin,Obestatin, and Ghrelin/Obestatin Ratio in Morbidly Obese Patients

Background  

Appetite-regulating hormones seem to play an important role in weight loss after bariatric surgery. Less is known regarding long-term weight loss maintenance. The objective of the study was to evaluate ghrelin and obestatin levels following long-term weight loss achieved through bariatric surgery or a lifestyle intervention in morbidly obese patients.     

Vagal Nerve Dissection During Pouch Formation in Laparoscopic Roux-Y-Gastric Bypass for Technical Simplification: Does it Matter?

Background  In Roux-Y gastric bypass surgery pouch formation is the most demanding part of the operation. The vagal nerve is usually tempted to be preserved although results reporting beneficial effects are lacking. Dividing the perigastric tissue including the anterior vagal trunk may technically alleviate gastric pouch formation. We evaluated the clinical outcome in patients with and without vagal nerve dissection in patients after Roux-Y gastric bypass (RY-BP). Methods  In this study 40 morbidly obese patients undergoing RY-BP have been included. Patients were divided into two groups according to vagal nerve preservation (Group 1, n = 25) or vagal nerve dissection (Group 2, n = 22). Clinical parameters (weight loss, complications, gastrointestinal symptoms), esophageal endoscopy, and motility data (manometry, pH-metry) and a satiety score were assessed. Serum values of ghrelin and gastrin were measured. Results  All procedures were performed by laparoscopy with a 0% mortality rate. One patient of each groups necessitated redo-laparoscopy (bleeding and a lost drainage). All patients significantly reduced body weight (p < 0.01 compared to preoperative) during a median follow-up of 36.1 months. Two patients of Group 2 showed acid reflux demonstrated by pathologic postoperative DeMeester scores. Esophageal body peristalsis and barium swallows did not reveal statistically significant differences between the two groups. Parameters of satiety assessment did not differ between the two groups as did serum values of gastrin and ghrelin. Conclusion  Pouch formation during RY-BP may be alleviated by simply dissecting the perigastric fatty tissue. In this way the anterior vagal trunk is dissected, however, no influence on clinical, functional and laboratory results occur.     

Serum C-Reactive Protein and White Blood Cell Count in Morbidly Obese Surgical Patients

Background  Obesity has been widely recognized as a chronic inflammatory condition and associated with elevated inflammatory indicators including C-reactive protein (CRP) and white blood cell count (WBC). Recent studies have shown elevated CRP or WBC is a significant risk factor for cardiac events and stroke but the clinical significance of CRP and WBC has not been clearly studied in morbidly obese patients. This study is aimed at the clinical significance of WBC and CRP in morbidly obese patients and the change after bariatric surgery. Methods  The study was a prospectively controlled clinical study. From December 1, 2001 to January 31, 2006, of 640 (442 females and 198 males) consecutive morbid obese patients enrolled in a surgically supervised weight loss program with at least 1 year’s follow-up were examined. Results  Of the patients, 476 (74.4%) had elevated CRP and 100 (15.6%) had elevated WBC at preoperative study. CRP and WBC were significantly related and both increased with increasing body mass index (BMI). CRP is also increased with increasing waist, glucose level, hemoglobin, albumin, Ca, insulin, C-peptide, and metabolic syndrome while WBC is increased with metabolic syndrome but decreased with increasing age. Multivariate analysis confirmed fasting glucose level and hemoglobin are independent predictors of the elevation of CRP while age is the only independent predictor for elevated WBC. Both WBC and CRP levels decreased rapidly after obesity surgery. These improvements resulted in a 69.8% reduction of CRP and 26.4% reduction of WBC 1 year after surgery. Although individuals who underwent laparoscopic gastric bypass lost significantly more weight (36.8 ± 11.7 kg vs. 17.3 ± 10.8 kg; p = 0.000) and achieved a lower BMI (27.8 ± 4.6 vs. 35.0 ± 5.5; p = 0.000) than individuals who underwent laparoscopic gastric banding, there was no difference in the resolution of elevated CRP 1 year after surgery (95.9% vs. 84.5%; p = 0.169) and WBC (99.4% vs. 98.3%; p = 0.323). Conclusions  Both baseline WBC and CRP are elevated in morbid obese patients but CRP has a better clinical significance. Significant weight reduction 1 year after surgery markedly reduced CRP and WBC with a resolution rate of 93.9% and 98.2% separately. Obesity surgery performed by laparoscopic surgery is recommended for obese patients with elevated CRP or WBC.     

Association of Ghrelin Receptor Promoter Polymorphisms with Weight Loss Following Roux-en-Y Gastric Bypass Surgery

Background  

Ghrelin plays a role in appetite and has been hypothesized to play a role in the mechanism of Roux-en-Y gastric bypass (RYGB) surgery. Single nucleotide polymorphisms (SNPs) in the promoter region of its receptor gene (growth hormone secretagogue receptor type 1a—GHSR) have also been associated with weight loss outcomes following long-term dietary intervention in adults with impaired glucose tolerance. Our objectives were to evaluate changes in serum ghrelin levels and determine the effect of GHSR promoter polymorphisms on post-RYGB surgery weight loss.     

Increase in Ghrelin Levels After Weight Loss in Obese Zucker Rats is Prevented by Gastric Banding

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.     

Increase of Osteopontin Plasma Concentrations After Bariatric Surgery Independent from Inflammation and Insulin Resistance

Background  Osteopontin (OPN) is a multifunctional matrix glycoprotein associated with bone metabolism and has been linked to chronic inflammation, insulin resistance, and atherosclerosis. Diet-induced weight loss decreases elevated OPN concentrations in obese patients. The aim of the current study was to investigate the role of OPN after bariatric surgery, where not only improvements of chronic inflammation, insulin resistance and comorbidities, but also malabsorption and altered bone metabolism have been reported. Methods  OPN plasma concentrations were determined in 31 morbidly obese patients (5 men, 26 women, BMI 46.2 ± 7.1 kg/m², age 41 ± 11 years; mean ± SD) before and 18 months after bariatric surgery, together with parameters of bone metabolism and inflammation. Results  OPN concentrations increased by +20.3 ± 26.6 ng/ml (mean ± SD, p < 0.01), concomitant to a weight loss of −38 ± 22 kg, and a decrease in BMI by −13.1 ± 7.7 kg/m² (both p < 0.01). HOMA-index improved from 5.2 ± 3.4 to 1.5 ± 1.0 (p < 0.01). Calcium concentrations slightly decreased, and phosphate increased (−0.06 ± 0.13 mmol/l and +0.08 ± 0.16 mmol/l, respectively; both p < 0.05), while 25-OH-VitaminD₃ remained unchanged and PTH tended to increase (+5.1 ± 14.0 pg/ml, p = 0.054). Monocyte chemoattractant protein 1 and interleukin 18 were significantly decreased and associated with HOMA both before and after bariatric surgery. ΔOPN was correlated with ΔPTH, but not with other parameters. Conclusions  OPN plasma concentrations increased concomitant to weight loss after bariatric surgery, which was independent from an improvement of insulin sensitivity and a decrease of inflammatory markers. Further studies are needed to differentiate whether these changes in bone metabolism after bariatric surgery are secondary to calcium deficiency or an adaptation to weight loss. This work has been submitted in abstract form and will be in part presented at the American Diabetes Association 68th Scientific Sessions 2008, June 6th–10th, San Francisco, CA, USA.     

Suboptimal Weight Loss after Gastric Bypass Surgery: Correlation of Demographics, Comorbidities, and Insurance Status with Outcomes

Although Roux-en-Y gastric bypass surgery (RYGBP) is safe and effective at achieving weight loss in the majority of severely obese patients, a subset fails to achieve expected weight loss outcomes. Factors associated with poor weight loss are not well defined. Patients undergoing open RYGBP using a standardized surgical technique and clinical pathway by a single surgeon at a dedicated bariatric center were reviewed. Suboptimal weight loss was defined as failure to lose at least 40% excess body weight by 12 months postoperatively. Of 555 consecutive patients who underwent RYGBP from 1999 to 2004, a 12-month follow-up was available for the 495 (89%). Suboptimal weight loss occurred in 55 (11%) and was associated on unadjusted bivariate analysis with increased body mass index (BMI; p = 0.0002), diabetes mellitus (p = 0.0002), Medicaid insurance (p = 0.04), and male sex (p = 0.01). On adjusted multivariate analysis, increased BMI (p = 0.003), diabetes (p = 0.002), and male gender (p = 0.04) were associated with suboptimal weight loss, but type of insurance (p = 0.11) was not. Medicaid patients were younger (p = 0.01) and had higher BMI (p = 0.0002). Suboptimal weight loss after RYGBP appears to be associated with greater BMI, male sex, and diabetes but not type of insurance. This study may help identify patients who could benefit from increased perioperative education and counseling or selection of procedures with greater malabsorption. Presented at the 48th Annual Meeting of The Society for Surgery of the Alimentary Tract, Washington DC, May 19–24, 2007.     

The decrease in serum IL-18 levels after bariatric surgery in morbidly obese women is a time-dependent event

Background We have evaluated the impact of the reproductive status of morbidly obese women, and of the time elapsed since surgery, on the response of the proinflammatory serum cardiovascular risk marker interleukin-18 (IL-18) to the sustained and marked weight loss achieved after bariatric surgery. Methods Serum IL-18 levels were measured in 33 morbidly obese women before bariatric surgery and after losing at least 15% of the initial weight, irrespective of the time needed to achieve this goal (5 to 33 months). Results Patients lost 30.7 ± 7.8% of the initial weight, with a concomitant reduction of serum IL-18 concentrations (P < 0.001). A stepwise multiple regression analysis showed that the percentual decrease in serum IL-18 levels was determined by the interaction between the time elapsed since surgery and the percentual reduction of waist circumference (R² = 0.333, F = 15.500, β = 0.577, P < 0.001), but not by the individual effects of the time elapsed since surgery, percentual body weight loss, percentual reduction of waist circumference, menopausal status or type of surgical procedure, or by the interaction between the time elapsed since surgery with the percentual body weight loss or with menopausal status. Conclusion Serum IL-18 levels decrease after bariatric surgery in a time-dependent manner, in relation to the reduction in waist circumference. The fact that the amelioration of the obesity-associated inflammatory process requires time and not only weight loss, might contribute to explain early non-surgical cardiovascular complications of bariatric surgery.