Ezetimibe ameliorates cholecystosteatosis

Effect of hepatic NPC1L1 on cholesterol gallstone disease and its mechanism

Cholesterol gallstone disease (CGD) is associated with bile cholesterol supersaturation. The Niemann-Pick C1-like 1 (NPC1L1), the inhibitory target of ezetimibe (EZE), is a critical sterol transporter of cholesterol absorption. Intestinal NPC1L1 facilitates the absorption of cholesterol, whereas hepatic NPC1L1 promotes cholesterol uptake by hepatocytes and reduces bile cholesterol supersaturation. The potential of hepatic NPC1L1 to prevent CGD has yet to be established due to its absence in the mice model. In this study, we generated mice expressing hepatic NPC1L1 using adeno-associated virus (AAV) gene delivery. The biliary cholesterol saturations and gallstone formations were explored under chow diet and lithogenic diet (LD) with or without EZE treatment. The long-term (8-week) LD-fed AAV-mNPC1L1 mice exhibited no significant differences in biliary cholesterol saturation and gallstone formation compared to WT mice. EZE effectively prevented CGD in both WT and AAV-mNPC1L1 mice. Mechanistically, prolonged LD feeding induced the degradation of hepatic NPC1L1, whereas short-term (2-week) LD feeding preserved the expression of hepatic NPC1L1. In conclusion, our findings suggest that hepatic NPC1L1 is unable to prevent CGD, whereas EZE functions as an efficient bile cholesterol desaturator during CGD development.

FGF15 promotes hepatic NPC1L1 degradation in lithogenic diet-fed mice

BACKGROUND

Cholesterol gallstone disease (CGD) is accompanied by biliary cholesterol supersaturation. Hepatic Niemann-Pick C1-like 1 (NPC1L1), which is present in humans but not in wild-type (WT) mice, promotes hepatocyte cholesterol uptake and decreases biliary cholesterol supersaturation. In contrast, intestinal NPC1L1 promotes intestinal cholesterol absorption, increasing biliary cholesterol supersaturation. Ezetimibe (EZE) can inhibit both hepatic and intestinal NPC1L1. However, whether hepatic NPC1L1 can affect CGD progress remains unknown.

METHODS

Mice expressing hepatic NPC1L1 (NPC1L1^hepatic-OE mice) were generated using Adeno-associated viruses (AAV) gene delivery. The protein level and function of hepatic NPC1L1 were examined under chow diet, high fat-cholesterol diet (HFCD), and lithogenic diet (LD) feeding. Gallstone formation rates were examined with or without EZE treatment. Fibroblast growth factor 15 (FGF15) treatment and inhibition of fibroblast growth factor receptor 4 (FGFR4) were applied to verify the mechanism of hepatic NPC1L1 degradation.

RESULTS

The HFCD-fed NPC1L1^hepatic-OE mice retained the biliary cholesterol desaturation function of hepatic NPC1L1, whereas EZE treatment decreased biliary cholesterol saturation and did not cause CGD. The ubiquitination and degradation of hepatic NPC1L1 were discovered in LD-fed NPC1L1^hepatic-OE mice. Treatment of FGF15 during HFCD feeding and inhibition of FGFR4 during LD feeding could affect the protein level and function of hepatic NPC1L1.

CONCLUSIONS

LD induces the ubiquitination and degradation of hepatic NPC1L1 via the FGF15-FGFR4 pathway. EZE may act as an effective preventative agent for CGD.

The Interpretation of Cholesterol Balance Derived Synthesis Data and Surrogate Noncholesterol Plasma Markers for Cholesterol Synthesis under Lipid Lowering Therapies

The cholesterol balance procedure allows the calculation of cholesterol synthesis based on the assumption that loss of endogenous cholesterol via fecal excretion and bile acid synthesis is compensated by de novo synthesis. Under ezetimibe therapy hepatic cholesterol is diminished which can be compensated by hepatic de novo synthesis and hepatic extraction of plasma cholesterol. The plasma lathosterol concentration corrected for total cholesterol concentration (R_Lath) as a marker of de novo cholesterol synthesis is increased during ezetimibe treatment but unchanged under treatment with ezetimibe and simvastatin. Cholesterol balance derived synthesis data increase during both therapies. We hypothesize the following. (1) The cholesterol balance data must be applied to the hepatobiliary cholesterol pool. (2) The calculated cholesterol synthesis value is the sum of hepatic de novo synthesis and the net plasma-liver cholesterol exchange rate. (3) The reduced rate of biliary cholesterol absorption is the major trigger for the regulation of hepatic cholesterol metabolism under ezetimibe treatment. Supportive experimental and literature data are presented that describe changes of cholesterol fluxes under ezetimibe, statin, and combined treatments in omnivores and vegans, link plasma R_Lath to liver function, and define hepatic de novo synthesis as target for regulation of synthesis. An ezetimibe dependent direct hepatic drug effect cannot be excluded.

Impaired Gallbladder Motility and Increased Gallbladder Wall Thickness in Patients with Nonalcoholic Fatty Liver Disease

BACKGROUND/AIMS

Nonalcoholic fatty liver disease (NAFLD) is currently the most common chronic liver disease worldwide. Along with the increase in the incidence of NAFLD and associated obesity, an increase in gallbladder disease (GD) has been noted. This has led to the identification of a new disease entity called fatty GD. There is a gap in the literature on the dynamics of gallbladder function in patients with NAFLD.

METHODS

An observational case-control study, a total of 50 patients with biopsy proven NAFLD without gallbladder stone/sludge and 38 healthy comparison subjects were enrolled. Fasting, postprandial gallbladder volumes (PGV), gallbladder ejection fraction (GEF), and fasting gallbladder wall thickness (FGWT) were measured by real-time 2-dimensional ultrasonography.

RESULTS

Fasting gallbladder wall thickness, fasting gallbladder volumes and PGV were significantly higher in patients with NAFLD than control subjects (P < 0.001, P = 0.006, and P < 0.001, respectively). Gallbladder ejection fraction was significantly lower in the NAFLD group than the controls (P = 0.008). The presence of NAFLD was an independent predictor for GEF, PGV, and FGWT. Also, steatosis grade was an independent predictor for GEF, and GEF was significantly lower in the nonalcoholic steatohepatitis (NASH) subgroup than the controls.

CONCLUSIONS

Gallbladder dysfunction and increase in gallbladder wall thickness exists in asymptomatic (without stone/sludge and related symptoms) patients with NAFLD and are useful in identifying fatty GD. Measurement of these variables in NAFLD patients may be useful in identifying those at higher risk for GD.

Prevention of cholesterol gallstones by inhibiting hepatic biosynthesis and intestinal absorption of cholesterol

BACKGROUND

Cholesterol cholelithiasis is a multifactorial disease influenced by a complex interaction of genetic and environmental factors and represents a failure of biliary cholesterol homoeostasis in which the physical-chemical balance of cholesterol solubility in bile is disturbed.

DESIGN

The primary pathophysiologic event is persistent hepatic hypersecretion of biliary cholesterol, which has both hepatic and small intestinal components. The majority of the environmental factors are probably related to Western-type dietary habits, including excess cholesterol consumption.

RESULTS

Laparoscopic cholecystectomy, one of the most commonly performed surgical procedures in the United States, is nowadays a major treatment for gallstones. However, it is invasive and can cause surgical complications, and not all patients with symptomatic gallstones are candidates for surgery. The hydrophilic bile acid, ursodeoxycholic acid (UDCA), has been employed as first-line pharmacological therapy in a subgroup of symptomatic patients with small, radiolucent cholesterol gallstones. Long-term administration of UDCA can promote the dissolution of cholesterol gallstones. However, the optimal use of UDCA is not always achieved in clinical practice because of failure to titrate the dose adequately.

CONCLUSIONS

Therefore, the development of novel, effective and noninvasive therapies is crucial for reducing the costs of health care associated with gallstones. In this review, we summarize recent progress in investigating the inhibitory effects of ezetimibe and statins on intestinal absorption and hepatic biosynthesis of cholesterol, respectively, for the treatment of gallstones, as well as in elucidating their molecular mechanisms by which combination therapy could prevent this very common liver disease worldwide.

[Obesity and gallbladder diseases]

Obesity is an important health problem in the world and related to many critical diseases, such as diabetes, cardiovascular disease, and metabolic syndrome. Obesity leads to fat infiltration of multiple organs and infiltrated adipose tissue produces many cytokines resulting in the dysfunction of organs such as the gallbladder. In the biliary diseases, obesity and overweight have been known as a major risk factor for gallstones. According to current studies, obesity, insulin resistance, hyperinsulinemia, and metabolic syndrome are related to various gallbladder diseases including gallbladder stones, cholecystitis, gallbladder polyps, and gallbladder cancers. We reviewed further literature on the obesity and gallbladder diseases, in aspects of epidemiology, mechanism, pathology and prevention.

Ezetimibe: its novel effects on the prevention and the treatment of cholesterol gallstones and nonalcoholic Fatty liver disease

The cholesterol absorption inhibitor ezetimibe can significantly reduce plasma cholesterol concentrations by inhibiting the Niemann-Pick C1-like 1 protein (NPC1L1), an intestinal sterol influx transporter that can actively facilitate the uptake of cholesterol for intestinal absorption. Unexpectedly, ezetimibe treatment also induces a complete resistance to cholesterol gallstone formation and nonalcoholic fatty liver disease (NAFLD) in addition to preventing hypercholesterolemia in mice on a Western diet. Because chylomicrons are the vehicles with which the enterocytes transport cholesterol and fatty acids into the body, ezetimibe could prevent these two most prevalent hepatobiliary diseases possibly through the regulation of chylomicron-derived cholesterol and fatty acid metabolism in the liver. It is highly likely that there is an intestinal and hepatic cross-talk through the chylomicron pathway. Therefore, understanding the molecular mechanisms whereby cholesterol and fatty acids are absorbed from the intestine could offer an efficacious novel approach to the prevention and the treatment of cholesterol gallstones and NAFLD.

Statins as potential treatment for cholesterol gallstones: an attempt to understand the underlying mechanism of actions

INTRODUCTION

Statin therapy is widely used across the globe for the treatment and prevention of cardiovascular disease (CVD). It is well established that statin therapy is associated with significant decreases in low-density lipoprotein cholesterol (LDL-C) and plasma cholesterol levels. Cholesterol gallstones are a common problem, resulting in hospital admission and surgery, throughout western healthcare systems.

AREAS COVERED

This review describes the mechanisms, and addresses the potential, for statins to be used as a treatment for gallstones. Medline was searched for the risk factors and treatment of cholesterol gallstones.

EXPERT OPINION

Obesity, metabolic syndrome, non-alcoholic fatty liver disease (NAFLD), insulin resistance and high-fat diets (unsaturated fats) rich in cholesterol are all associated risk factors for cholesterol gallstones. In view of the high prevalence of cholesterol gallstones, there is an urgent need to understand whether pharmacological therapies can be harnessed for the treatment of cholesterol gallstones. Gallstones are shown to be associated with an increased risk, not only of mortality, but also of CVD. Statins, widely used in prevention of CVD and hypercholesteremia, have been shown to dissolve cholesterol gallstones in animal models and human studies, highlighting the potential for a pharmacological therapy for gallstones. More studies are required to understand the role of statins in the treatment of gallstones and for comparison with current treatment strategies.

Ezetimibe decreases SREBP-1c expression in liver and reverses hepatic insulin resistance in mice fed a high-fat diet

Ezetimibe inhibits intestinal cholesterol absorption, thereby reducing serum cholesterol. Recent studies suggest that ezetimibe affects liver steatosis and insulin resistance. We investigated the impact of ezetimibe on insulin sensitivity and glucose metabolism in C57BL/6 mice. We analyzed 4 mouse groups fed the following diets: normal chow (4% fat) for 12 weeks, normal chow for 10 weeks followed by normal chow plus ezetimibe for 2 weeks, high-fat chow (32% fat) for 12 weeks, and high-fat chow for 10 weeks followed by high-fat chow plus ezetimibe for 2 weeks. In the normal chow + ezetimibe group, ezetimibe had no impact on body weight, fat mass, lipid metabolism, liver steatosis, glucose tolerance, or insulin sensitivity. In the high-fat chow + ezetimibe group, ezetimibe had no impact on body weight or fat mass but significantly decreased serum low-density lipoprotein cholesterol, triglyceride, and glutamate pyruvate transaminase levels; liver weight; hepatic triglyceride content; and hepatic cholesterol content and increased the hepatic total bile acid content. In association with increases in IRS-2 and Akt phosphorylation, ezetimibe ameliorated hepatic insulin resistance in the high-fat chow + ezetimibe group, but had no effect on insulin sensitivity in primary cultured hepatocytes. A DNA microarray and Taqman polymerase chain reaction revealed that ezetimibe up-regulated hepatic SREBP2 and SHP expression and down-regulated hepatic SREBP-1c expression. SHP silencing mainly in the liver worsened insulin resistance, and ezetimibe protected against insulin resistance induced by down-regulation of SHP. Ezetimibe down-regulated SREBP-1c in the liver and reversed hepatic insulin resistance in mice fed a high-fat diet.

Potential therapeutic uses for ezetimibe beyond lowering LDL-c to decrease cardiovascular events

Ezetimibe is a relatively new drug that inhibits the absorption of dietary cholesterol in the small intestine. It is a low density lipoprotein-cholesterol (LDL-C) lowering medication that acts directly on the intestine by inhibiting Niemann-Pick C1 Like1 (NPC1L1). Recently, results of the ARBITER 6-HALTS trial (Arterial Biology for the Investigation of the Treatment Effects of Reducing Cholesterol 6-HDL and LDL Treatment Strategies) and the ENHANCE trial (Ezetimibe and Simvastatin in Hypercholesterolemia Enhances Atherosclerosis Regression) showed that ezetimibe had no effect on atherosclerosis despite producing a marked decrease in LDL-C. Recent studies show a potential benefit of ezetimibe in treating insulin resistance, non-alcoholic fatty liver disease (NAFLD), gallstones and dyslipidaemia associated with chronic renal failure and organ transplantation. All of these conditions are known to be associated with an increase in risk of cardiovascular disease (CVD) and further studies are needed to assess the potential benefits of ezetimibe in these therapeutics areas.

Targets for current pharmacologic therapy in cholesterol gallstone disease

Gallstone disease is a frequent condition throughout the world and, cholesterol stones are the most frequent form in Western countries. The standard treatment of symptomatic gallstone subjects is laparoscopic cholecystectomy. The selection of patients amenable for nonsurgical, medical therapy is of key importance; a careful analysis should consider the natural history of the disease and the overall costs of therapy. Only patients with mild symptoms and small, uncalcified cholesterol gallstones in a functioning gallbladder with a patent cystic duct are considered for oral litholysis by hydrophilic ursodeoxycholic acid, in the hope of achieving cholesterol desaturation of bile and progressive stone dissolution. Recent studies have raised the possibility that cholesterol-lowering agents that inhibit hepatic cholesterol synthesis (statins) or intestinal cholesterol absorption (ezetimibe), or drugs acting on specific nuclear receptors involved in cholesterol and bile acid homeostasis, may offer, alone or in combination, additional medical therapeutic tools for treating cholesterol gallstones. Recent perspectives on medical treatment of cholesterol gallstone disease are discussed in this article.

Ezetimbe as potential treatment for cholesterol gallstones: The need for clinical trials

Obesity is associated with insulin resistance, non-alcoholic fatty liver disease (NAFLD) and gallstones. High fat diets (unsaturated fats) rich in cholesterol have been demonstrated to produce not only gallstones but also NAFLD and insulin resistance. Interestingly, a high incidence of gallstones is being reported in association with insulin resistance and NAFLD. Laparoscopic cholecystectomy is the best definitive therapy for symptomatic gallbladder disease. Ezetimibe is a drug that inhibits the absorption of both dietary and biliary cholesterol in the small intestine. Importantly, ezetimibe showed potential benefit not only in treating and preventing gallstones but also in insulin resistance and NAFLD. Further studies are required before the use of ezetimibe for the treatment of gallstones can be advocated.

Steatocholecystitis and fatty gallbladder disease

Obesity has become an epidemic worldwide. It is accompanied by a multitude of medical complications including metabolic syndrome. Obesity may lead to fatty infiltration of multiple internal organs including liver, heart, kidney, and pancreas, causing organ dysfunctions. Fatty infiltration leads to chronic inflammation and tissue damage. Fatty infiltration in the liver results in nonalcoholic fatty liver disease, which is increasingly common nowadays. Recent studies in animals and humans indicate that obesity also is associated with fatty infiltration of gallbladder, resulting in cholecystosteatosis. The increased gallbladder lipids include free fatty acids, phospholipids, and triglycerides. Enhanced inflammation with an increased amount of fat in the gallbladder results in an abnormal wall structure and decreased contractility. In support of this notion, a recent experiment on the effect of Ezetimibe, which is a novel drug that inhibits intestinal fat absorption, on fatty gallbladder disease reveals that Ezetimibe can ameliorate cholecystosteatosis and restore in vivo gallbladder contractility. The proportion of cholecystectomies performed for chronic acalculous cholecystitis has increased significantly over the past two decades. An increase in gallbladder fat, which leads to poor gallbladder emptying and biliary symptoms, may partly explain this phenomenon. Although dietary carbohydrates have been demonstrated to be associated with fatty gallbladder disease, other potential modifiable environmental factors are not clear. The pathogenesis and prognosis of fatty gallbladder disease, including steatocholecystitis, and the relations of fatty gallbladder disease to nonalcoholic fatty liver disease, including steatohepatitis, and other components of metabolic syndrome are largely unknown. More research is needed to answer these questions.

Inhibiting intestinal NPC1L1 activity prevents diet-induced increase in biliary cholesterol in Golden Syrian hamsters

Niemann-Pick C1-like 1 (NPC1L1) facilitates the uptake of sterols into the enterocyte and is the target of the novel cholesterol absorption inhibitor, ezetimibe. These studies used the Golden Syrian hamster as a model to delineate the changes in the relative mRNA expression of NPC1L1 and other proteins that regulate sterol homeostasis in the enterocyte during and following cessation of ezetimibe treatment and also to address the clinically important question of whether the marked inhibition of cholesterol absorption alters biliary lipid composition. In hamsters fed a low-cholesterol, low-fat basal diet, the abundance of mRNA for NPC1L1 in the small intestine far exceeded that in other regions of the gastrointestinal tract, liver, and gallbladder. In the first study, female hamsters were fed the basal diet containing ezetimibe at doses up to 2.0 mg.day(-1).kg body wt(-1). At this dose, cholesterol absorption fell by 82%, fecal neutral sterol excretion increased by 5.3-fold, and hepatic and intestinal cholesterol synthesis increased more than twofold, but there were no significant changes in either fecal bile acid excretion or biliary lipid composition. The ezetimibe-induced changes in intestinal cholesterol handling were reversed when treatment was withdrawn. In a second study, male hamsters were given a diet enriched in cholesterol and safflower oil without or with ezetimibe. The lipid-rich diet raised the absolute and relative cholesterol levels in bile more than fourfold. This increase was largely prevented by ezetimibe. These data are consistent with the recent finding that ezetimibe treatment significantly reduced biliary cholesterol saturation in patients with gallstones.

A murine model of obesity implicates the adipokine milieu in the pathogenesis of severe acute pancreatitis

Obesity is clearly an independent risk factor for increased severity of acute pancreatitis (AP), although the mechanisms underlying this association are unknown. Adipokines (including leptin and adiponectin) are pleiotropic molecules produced by adipocytes that are important regulators of the inflammatory response. We hypothesized that the altered adipokine milieu observed in obesity contributes to the increased severity of pancreatitis. Lean (C57BL/6J), obese leptin-deficient (LepOb), and obese hyperleptinemic (LepDb) mice were subjected to AP by six hourly intraperitoneal injections of cerulein (50 microg/kg). Severity of AP was assessed by histology and by measuring pancreatic concentration of the proinflammatory cytokines IL-1beta and IL-6, the chemokine MCP-1, and the marker of neutrophil activation MPO. Both congenitally obese strains of mice developed significantly more severe AP than wild-type lean animals. Severity of AP was not solely related to adipose tissue volume: LepOb mice were heaviest; however, LepDb mice developed the most severe AP both histologically and biochemically. Circulating adiponectin concentrations inversely mirrored the severity of pancreatitis. These data demonstrate that congenitally obese mice develop more severe AP than lean animals when challenged by cerulein hyperstimulation and suggest that alteration of the adipokine milieu exacerbates the severity of AP in obesity.

Ezetimibe prevents cholesterol gallstone formation in mice

BACKGROUND

Intestinal cholesterol absorption may influence gallstone formation and its modulation could be a useful therapeutic strategy for gallstone disease (GSD). Ezetimibe (EZET) is a cholesterol-lowering agent that specifically inhibits intestinal cholesterol absorption.

AIMS

To test whether EZET can prevent gallstone formation in mice.

METHODS/RESULTS

Gallstone-susceptible C57BL/6 inbred mice were fed control and lithogenic diets with or without simultaneous EZET administration. Lithogenic diet increased biliary cholesterol content and secretion, and induced sludge or gallstone formation in 100% of the animals. EZET administration reduced intestinal cholesterol absorption by 90% in control animals and by 35% in mice receiving the lithogenic diet. EZET prevented the appearance of cholesterol crystals and gallstones. In addition, mice fed the lithogenic diet plus EZET exhibited a 60% reduction in biliary cholesterol saturation index. Of note, EZET treatment caused a significant increase in bile flow (+50%, P<0.01) as well as bile salt, phospholipid and glutathione secretion rates (+60%, +44% and +100%, respectively, P<0.01), which was associated with a moderately increased expression of hepatic bile salt transporters. In addition, relative expression levels of Nieman-Pick C1 like 1 (NPC1L1) in the enterohepatic axis in humans were assessed. Expression levels of NPC1L1 were 15- to 30-fold higher in the duodenum compared with the liver at transcript and protein levels, respectively, suggesting preferential action of EZET on intestinal cholesterol absorption in humans.

CONCLUSIONS

In a murine model of GSD, EZET prevented gallstone formation by reducing intestinal cholesterol absorption and increasing bile salt-dependent and -independent bile flow. EZET could be useful in preventing GSD disease in susceptible patients.

Effect of ezetimibe on the prevention and dissolution of cholesterol gallstones

BACKGROUND & AIMS

Cholesterol cholelithiasis is one of the most prevalent and most costly digestive diseases in developed countries and its incidence has increased markedly in Asian countries owing to the adoption of Western-type dietary habits. Because animal experiments showed that high efficiency of intestinal cholesterol absorption contributes to gallstone formation, we explored whether the potent cholesterol absorption inhibitor ezetimibe could prevent gallstones and promote gallstone dissolution in mice and reduce biliary cholesterol content in human beings.

METHODS

Male gallstone-susceptible C57L mice were fed a lithogenic diet and concomitantly administered with ezetimibe at 0, 0.8, 4, or 8 mg/kg/day for 8 or 12 weeks. Gallbladder biles and gallstones were examined by microscopy. Gallbladder emptying in response to cholecystokinin octapeptide was measured gravimetrically. Biliary lipid outputs were analyzed by physical-chemical methods. Cholesterol absorption efficiency was determined by fecal dual-isotope ratio and mass balance methods. Lipid changes in gallbladder biles of gallstone patients vs overweight subjects without gallstones were examined before (day 0) and at 30 days after ezetimibe treatment (20 mg/day).

RESULTS

Ezetimibe prevented gallstones by effectively reducing intestinal cholesterol absorption and biliary cholesterol secretion, and protected gallbladder motility function by desaturating bile in mice. Treatment with ezetimibe promoted the dissolution of gallstones by forming an abundance of unsaturated micelles. Furthermore, ezetimibe significantly reduced biliary cholesterol saturation and retarded cholesterol crystallization in biles of patients with gallstones.

CONCLUSIONS

Ezetimibe is a novel approach to reduce biliary cholesterol content and a promising strategy for preventing or treating cholesterol gallstones by inhibiting intestinal cholesterol absorption.

Steatocholecystitis: the influence of obesity and dietary carbohydrates

INTRODUCTION

We have recently demonstrated that obese and lean mice fed a high fat diet have increased gallbladder wall fat and decreased gallbladder contractility, cholecystosteatosis. Animal and human data also suggest that diets high in refined carbohydrates lead to gallstone formation. However, no data are available on the role of dietary carbohydrates on gallbladder wall fat and inflammation. Therefore, we tested the hypothesis that both obesity and dietary carbohydrates would increase gallbladder fat and cytokines, steatocholecystitis.

METHODS

At 8 wk of age, 47 lean and 22 obese female mice were fed a 45% carbohydrate (CHO) diet while an equal number of lean and obese mice were fed a 75% CHO diet for 4 wk. All mice underwent cholecystectomy, and the gallbladders were snap-frozen. Individual and total lipids were measured by gas chromatography. Interleukin (IL)-1beta, tumor necrosis factor (TNF)-alpha, and IL-6 were measured by enzyme-linked immunosorbent assay. Data were analyzed by analysis of variance and Tukey test.

RESULTS

Gallbladder total fat, triglycerides, and cholesterol were maximum (P < 0.001) in obese mice on the 75% CHO diet. Gallbladder TNF-alpha and IL-1beta as well as serum cholesterol levels showed a similar pattern (P < 0.001). Gallbladder saturated free fatty acids and IL-6 levels were highest (P < 0.001) in obese mice on the 45% CHO diet.

CONCLUSIONS

These data suggest that (1) both obesity and dietary carbohydrates increase gallbladder total fat, triglycerides, cholesterol, TNF-alpha, and IL-1beta and (2) obesity also increases gallbladder free fatty acids and IL-6. Therefore, we conclude that obesity is associated with steatocholecystitis and that a high carbohydrate diet exacerbates this phenomenon.