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1.
Changes in Insulin Resistance Following Bariatric Surgery: Role of Caloric Restriction and Weight Loss 总被引:6,自引:6,他引:0
The prevalence of type 2 diabetes mellitus (T2DM) and obesity in the western world is steadily increasing. Bariatric surgery
is an effective treatment of T2DM in obese patients. The mechanism by which weight loss surgery improves glucose metabolism
and insulin resistance remains controversial. In this review, we propose that two mechanisms participate in the improvement
of glucose metabolism and insulin resistance observed following weight loss and bariatric surgery: caloric restriction and
weight loss. Nutrients modulate insulin secretion through the entero-insular axis. Fat mass participates in glucose metabolism
through the release of adipocytokines. T2DM improves after restrictive and bypass procedures, and combinations of restrictive
and bypass procedures in morbidly obese patients. Restrictive procedures decrease caloric and nutrient intake, decreasing
the stimulation of the entero-insular axis. Gastric bypass (GBP) operations may also affect the entero-insular axis by diverting
nutrients away from the proximal GI tract and delivering incompletely digested nutrients to the distal GI tract. GBP and biliopancreatic
diversion combine both restrictive and bypass mechanisms. All procedures lead to weight loss and decrease in the fat mass.
Decrease in fat mass significantly affects circulating levels of adipocytokines, which favorably impact insulin resistance.
The data reviewed here suggest that all forms of weight loss surgery lead to caloric restriction, weight loss, decrease in
fat mass and improvement in T2DM. This suggests that improvements in glucose metabolism and insulin resistance following bariatric
surgery result in the short-term from decreased stimulation of the entero-insular axis by decreased caloric intake and in
the long-term by decreased fat mass and resulting changes in release of adipocytokines. Observed changes in glucose metabolism
and insulin resistance following bariatric surgery do not require the posit of novel regulatory mechanisms. 相似文献
2.
Baranova A Gowder SJ Schlauch K Elariny H Collantes R Afendy A Ong JP Goodman Z Chandhoke V Younossi ZM 《Obesity surgery》2006,16(9):1118-1125
Background: Adipose tissue is an active endocrine organ that secretes a variety of metabolically important substances including
adipokines. These factors affect insulin sensitivity and may represent a link between obesity, insulin resistance, type 2
diabetes (DM), and nonalcoholic fatty liver disease (NAFLD). This study uses real-time polymerase chain reaction (PCR) quantification
of mRNAs encoding adiponectin, leptin, and resistin on snap-frozen samples of intra-abdominal adipose tissue of morbidly obese
patients undergoing bariatric surgery. Methods: Morbidly obese patients undergoing bariatric surgery were studied. Patients
were classified into two groups: Group A (with insulin resistance) (N=11; glucose 149.84 ± 40.56 mg/dL; serum insulin 8.28
± 3.52 μU/mL), and Group B (without insulin resistance) (N=10; glucose 102.2 ± 8.43 mg/dL; serum insulin 3.431 ± 1.162 μU/mL).
Results: Adiponectin mRNA in intra-abdominal adipose tissue and serum adiponectin levels were significantly lower in Group
A compared to Group B patients (P<0.016 and P<0.03, respectively). Although serum resistin was higher in Group A than in Group B patients (P<0.005), resistin gene expression was not different between the two groups. Finally, for leptin, neither serum level nor gene
expression was different between the two groups. Serum adiponectin level was the only predictor of nonalcoholic steatohepatitis
(NASH) in this study (P=0.024). Conclusions: Obese patients with insulin resistance have decreased serum adiponectin and increased serum resistin.
Additionally, adiponectin gene expression is also decreased in the adipose tissue of these patients. This low level of adiponectin
expression may predispose patients to the progressive form of NAFLD or NASH. 相似文献
3.
Is Ghrelin the Culprit for Weight Loss after Gastric Bypass Surgery? A Negative Answer 总被引:2,自引:2,他引:0
Background: Ghrelin is a potent appetite stimulator, mainly synthesized in the stomach. Paradoxically, obese subjects have
lower plasma ghrelin than lean subjects and increase their weight in spite of low ghrelin levels. The role of ghrelin in weight
regulation after bariatric surgery is still controversial. The aim of this study was to evaluate whether rapid weight loss
after laparoscopic Roux-en-Y gastric bypass surgery (LRYGBP), was associated with changes in plasma ghrelin levels. In addition,
we determined the acute impact of LRYGBP on insulin resistance and adiponectin levels. Methods: 49 morbidly obese subjects
who underwent LRYGBP were studied. 19 subjects who underwent other laparoscopic gastrointestinal surgeries acted as the control
group. Fasting plasma levels of ghrelin, insulin and adiponectin were determined preoperatively and 2 hours, 10 days and 6
months postoperatively. Results: At 2 hours after LRYGBP, there was a significant reduction in ghrelin and adiponectin levels,
which coincided with elevated plasma glucose and insulin levels. Interestingly, once glucose and insulin levels normalized
at 6 months after surgery, ghrelin also normalized. Adiponectin reached pre-surgical levels at 10 days after LRYGBP and continued
to significantly rise until 6 months postoperatively. Conclusion: Weight loss after LRYGBP occurs in spite of the absence
of significant changes in plasma ghrelin levels. Improvement of insulin resistance occurred within 10 days after surgery,
and could be related to the normalization of adiponectin levels. This data questions the role of peripheral ghrelin as a cause
of weight loss in obese humans after LRYGBP. 相似文献
4.
Marianna Argentou Dina G. Tiniakos Menelaos Karanikolas Maria Melachrinou Maria G. Makri Christos Kittas Fotis Kalfarentzos 《Obesity surgery》2009,19(9):1313-1323
Background Leptin, adiponectin, and resistin are adipokines linked to the development of insulin resistance, which plays a central role
in the pathogenesis of nonalcoholic fatty liver disease (NAFLD). We aimed to define adipokine serum levels in severely obese
patients undergoing bariatric surgery and to correlate these with anthropometric and metabolic variables, liver function tests,
and histopathological parameters of NAFLD and nonalcoholic steatohepatitis (NASH).
Methods Surgical liver biopsies were obtained from 50 bariatric patients with no history of liver disease or significant alcohol consumption.
Serum leptin, adiponectin, and resistin levels were measured, and histology was assessed using Brunt’s and Kleiner’s scoring
systems.
Results Waist/hip ratio was significantly higher in men (p = 0.0001), and leptin (p = 0.036) and adiponectin (p = 0.0001) serum levels were higher in women. Forty-one of 50 patients (82%) had histological NAFLD, including 10 (20%) with
NASH. Nine patients (18%) had normal liver histology (obese control subgroup). In NAFLD patients, serum adiponectin was negatively
correlated with activity grade and fibrosis stage, resistin was negatively correlated with steatosis grade (p = 0.033), while leptin was not related to histology. Leptin/adiponectin ratio showed positive association with stage (p = 0.044). In the subgroup of NASH patients, adiponectin was negatively correlated only with stage (p = 0.01), while there was no correlation between leptin, resistin, or leptin/adiponectin and histology.
Conclusions Serum adiponectin and resistin levels are related to liver histology in bariatric patients and may be indicative of the histological
severity of NAFLD and the extent of hepatic steatosis, respectively. Serum leptin levels are not informative of underlying
liver histology in severely obese patients.
Marianna Argentou and Dina G. Tiniakos contributed equally to this work.
The authors disclose no conflict of interest. 相似文献
5.
Background
Type 2 diabetes (T2D) resolves rapidly after bariatric surgery, even before substantial weight is lost. However, the molecular pathways underlying this phenomenon remain unclear. Microarray data has shown that numerous genes are differentially expressed in blood after bariatric surgery, including resistin and leptin. Resistin and leptin are circulating hormones derived from adipose tissue, which are associated with obesity and insulin resistance. This study examined expression of these genes before and after bariatric surgery in diabetic and nondiabetic obese patients. 相似文献6.
Marantos G Daskalakis M Karkavitsas N Matalliotakis I Papadakis JA Melissas J 《World journal of surgery》2011,35(9):2022-2030
Background
The aim of the present study was to evaluate the effects of surgically induced weight loss on the metabolic profile and adipocytokine levels in premenopausal morbidly obese females.Methods
Twenty premenopausal morbidly obese (MO) women with a median age of 34?years (range: 24?C48?years) and a median body mass index (BMI) of 41.47?kg/m2 (range: 38.0?C56.73?kg/m2) were studied (13 women underwent gastric banding and 7 women underwent sleeve gastrectomy). In addition, 20 lean premenopausal women with a median age of 32?years (range: 22?C44?years) and a median BMI of 20.0?kg/m2 (range: 18.5?C24.7?kg/m2) were also studied. Anthropometric measurements and metabolic parameters were analyzed in each patient, along with changes in leptin, adiponectin, resistin, and interleukin-6 (IL-6) before surgery, 6?months after surgery, and 12?months after surgery. Comparisons with the reference normal-weight subjects were also performed.Results
Both weight and BMI were found to be significantly decreased postoperatively. A 54.5% loss of excess BMI was observed 12?months after surgery, and was associated with significant improvement in all anthropometric and metabolic parameters. Twelve months after surgery we also observed decreased levels of serum leptin, resistin, and IL-6; increased levels of serum adiponectin; and a remarkable improvement in metabolic syndrome markers. Furthermore, postoperative serum resistin and IL-6 levels were found to reach those of normal-weight volunteers.Conclusions
The results of this study suggest that weight loss through restrictive bariatric surgery results in a significant reduction in leptin, resistin, and IL-6 levels, and an increase in adiponectin levels, in addition to improving insulin sensitivity and glucose and lipid homeostasis in young morbidly obese female patients. These changes were significantly correlated with the magnitude of weight loss. 相似文献7.
Ghrelin,Leptin and Insulin Levels after Restrictive Surgery: a 2-Year Follow-up Study 总被引:2,自引:2,他引:0
Background: Ghrelin is a recently discovered orexigenic gastric hormone, whose production is induced by lack of food in the
stomach. In morbidly obese individuals, ghrelin levels are low compared to lean persons. During dieting, plasma ghrelin levels
increase, leading to an orexigenic signal, which could explain the lack of success of dieting in morbidly obese individuals.
Morbid obesity is best treated with bariatric surgery, in which gastric bypass is reported to be more effective than restrictive
surgery. A possible explanation could be the difference in plasma ghrelin levels after both operations for bariatric surgery.
In this study, plasma ghrelin levels were investigated during a 2-year follow-up. Methods: 17 morbidly obese patients received
gastric restrictive surgery. Plasma ghrelin, leptin and insulin levels were evaluated preoperatively and 1 year and 2 years
postoperatively. Results: BMI decreased from 47.5 ± 6.2 kg/m2 to 33.2 ± 5.8 kg/m2 (P <0.001). Plasma ghrelin levels were significantly increased 1 year (P <0.05) and 2 years (P <0.02) postoperatively. Fasting plasma leptin and insulin levels were significantly lower at 2 years after surgery (P <0.001). Conclusion: After gastric restrictive surgery, ghrelin levels increased, in contrast to the reported fall in ghrelin
levels after gastric bypass. This difference in ghrelin levels between these operations may be the k ey to understanding the
superiority of gastric bypass in sustaining weight loss compared with restrictive surgery. 相似文献
8.
Serum Leptin Levels After Bariatric Surgery Across a Range of Glucose Tolerance from Normal to Diabetes 总被引:3,自引:0,他引:3
Bruno Geloneze MD Marcos Antonio Tambascia PhD Enrico Maluf Repetto PhD Sandra Grandim Pereira MD José Carlos Pareja MD PhD Luis Alberto Magna PhD 《Obesity surgery》2001,11(6):693-698
Background: A longitudinal, clinical intervention study with bariatric surgery was done to investigate the relationship between
leptin levels, BMI, and insulin during weight loss across a range of glucose tolerance from normal to diabetes. Methods: 43
morbidly obese patients (BMI: 42-75 kg/m2) undergoing vertical banded gastroplasty Roux-en-Y gastric bypass (VBG-RGB), were divided into 3 groups: 21 normal (NGT),
12 impaired glucose tolerance (IGT) and 10 type 2 diabetes (DM). Leptin, insulin, glucose, lipids and uric acid were measured
at baseline and 2, 4, 6, and 12 months following surgery. Results: BMI fell from 54.1 ± 9.1 to 34.6 ± 6.3 kg/m2, similarly in all groups. Leptin decreased from 73.9 ± 8.7 to 16.9 ± 10.2 ng/ml and was strongly correlated with BMI during
1-year follow-up (r=0.78; p<0.001). Linear univariate analysis for repeated evaluation showed a positive correlation between
leptin and glucose, triglycerides, uric acid, and insulin. Multivariate regression analysis indicated that BMI was independently
correlated with the decrease in leptin (p<0.001), accounting for 66% of the variance in leptin levels during weight loss.
These results were found in the NGT and IGT groups. In the DM group, a small additional influence in leptin levels was attributed
to glucose decrease. Conclusions: A strong link between leptin and BMI was found after surgery. BMI was the main determinant
of the decrease of leptin. In these patients submitted to bariatric surgery, ranging from normal glucose tolerance to diabetes,
changes in insulin levels and metabolic parameters, except for glucose in the DM group, did not appear to be correlated with
changes in leptin levels. 相似文献
9.
Decrease in Circulating Glucose, Insulin and Leptin Levels and Improvement in Insulin Resistance at 1 and 3 Months after Gastric Bypass 总被引:1,自引:1,他引:0
Background: Hyperglycemia, insulin resistance and hyperleptinemia are some of the consequences of obesity. Gastric bypass
for morbid obesity provides gastric restriction with decreased energy absorption. To confirm and extend previous reports in
the literature, we evaluated the plasma glucose, serum insulin and leptin and insulin resistance of patients preoperatively
and 1 and 3 months after Roux-en-Y gastric bypass (RYGBP). Methods: We determined body mass index (BMI), plasma glucose (glucose-oxidase
method), serum leptin (immunoassay) and insulin (chemiluminescent immunometric assay), and insulin resistance index (IRI)
by Homeostasis Model Assessment (HOMA) of 20 patients with morbid obesity both preoperatively and 1 and 3 months after RYGBP.
Results: Patients showed a mean decrease in weight of 8 kg/month. Glycemia was above reference levels in 65% of the preoperative
patients but dropped significantly 1 month postoperatively, serum insulin and leptin levels and the HOMA index also decreasing
significantly in the same period. The percentage of patients with preoperative elevated serum insulin and leptin relative
to reference levels decreased significantly following RYGBP. We also observed a weak but significant correlation between BMI
and glucose, BMI and insulin, and leptin and insulin. Conclusions: The beneficial effects of bariatric surgery are already
noticeable 1 month postoperatively, the reduction in insulin levels being more important for leptin reduction than decreased
BMI. Leptin appeared to be subject to multifactorial control and showed a larger reduction than body weight. 相似文献
10.
Ruano M Silvestre V Castro R García-Lescún MC Rodríguez A Marco A García-Blanch G 《Obesity surgery》2005,15(5):670-676
Background: Resistance to insulin and secondary hyperinsulinemia seem to be the putative link between morbid obesity (MO)
and hypertensive disease (HD). Adipose tissue can secrete leptin and angiotensinogen, among other substances. Leptin activates
the sympathetic nervous system, leading to HD. Angiotensinogen is a substrate for renin, therefore taking part in the renin-angiotensin-aldosterone
axis and the regulation of blood pressure. In MO, both hypertrophy and hyperplasia of the adipocytes lead to an increase in
the secretion of both substances, leading to loss of the equilibrium between the levels of both hormones. The aim of the present
study was to evaluate these abnormalities and their potential reversibility following bariatric surgery. Methods: Data from
100 patients with MO was retrospectively evaluated. Anthropometric data, the plasma renin activity (PRA), plasma levels of
aldosterone, ACE, potassium and sodium were collected both prior to surgery and 6, 12, 24 and 36 months after surgery. Results:
The waist-hip ratio (WHR) before surgery allowed classification of our patients in two groups: central obesity (WHR ≥0.90 in men and ≥0.85 in women); peripheral obesity (WHR <0.90 in men and <0.85 in women). In patients with central obesity, high levels of PRA, aldosterone and ACE
with sodium retention and potassium loss and high insulin levels, were found. These changes were not found in patients with
peripheral obesity. After gastric bypass, these abnormalities tended to disappear, mainly in the first 6 months. Conclusions:
The reduction of BMI and WHR after gastric bypass confirmed this operation to be effective against MO. The high basal levels
of insulin and the high rate of HD and diabetes in patients with central obesity seem to indicate that they suffer a metabolic
syndrome with significant hormonal imbalances and sodium retention. Patients with peripheral obesity only showed a peripheral
resistance against insulin, probably with a shorter duration of the hormonal action, but they did not show hormonal abnormalities
or sodium retention. After gastric bypass these abnormal hormone levels tended to normalize. 相似文献