Colon Involvement in Necrotizing Pancreatitis: Incidence, Risk Factors, and Outcomes.

OBJECTIVE: To investigate the incidence, risk factors, and outcomes of colon involvement in patients with necrotizing pancreatitis. SUMMARY/BACKGROUND DATA: Necrotizing pancreatitis is characterized by a profound inflammatory response with local and systemic implications. Mesocolic involvement can compromise colonic blood supply leading to ischemic complications; however, few data exist regarding this problem. We hypothesized that the development of colon involvement in necrotizing pancreatitis (NP) negatively affects morbidity and mortality. METHODS: Six hundred forty-seven NP patients treated between 2005 and 2017 were retrospectively reviewed to identify patients with colon complications, including ischemia, perforation, fistula, stricture/obstruction, and fulminant Clostridium difficile colitis. Clinical characteristics were analyzed to identify risk factors and effect of colon involvement on morbidity and mortality. RESULTS: Colon involvement was seen in 11% (69/647) of NP patients. Ischemia was the most common pathology (n = 29) followed by perforation (n = 18), fistula (n = 12), inflammatory stricture (n = 7), and fulminant C difficile colitis (n = 3). Statistically significant risk factors for developing colon pathology include tobacco use (odds ratio (OR), 2.0; 95% confidence interval (CI), 1.2-3.4, P = 0.009), coronary artery disease (OR, 1.9; 95% CI, 1.1-3.7; P = 0.04), and respiratory failure (OR, 4.7; 95% CI, 1.1-26.3; P = 0.049). When compared with patients without colon involvement, NP patients with colon involvement had significantly increased overall morbidity (86% vs 96%, P = 0.03) and mortality (8% vs 19%, P = 0.002). CONCLUSION: Colon involvement in necrotizing pancreatitis is common; clinical deterioration should prompt its evaluation. Risk factors include tobacco use, coronary artery disease, and respiratory failure. Colon involvement in necrotizing pancreatitis is associated with substantial morbidity and mortality.

Acute pancreatitis in obesity: adipokines and dietary fish oil.

BACKGROUND: Acute pancreatitis is a substantial clinical problem accounting for 240,000 hospital admissions yearly in the United States. Obesity is epidemic and is clearly an independent risk factor for increased severity of acute pancreatitis (AP). Adipose tissue is an endocrine organ that secretes a variety of metabolically active substances termed adipokines. However, the role of adipokines in modulating acute pancreatitis severity remains incompletely understood. Dietary fish oil is rich in omega-3 free fatty acids and attenuates adipose tissue-induced inflammation. Therefore, we hypothesized that feeding obese mice diets rich in fish oil would alter the adipokine milieu and attenuate the severity of pancreatitis. METHODS: Lean (C57BL/6 J) and obese (LepDb) mice were fed either a soybean oil- or fish oil-rich diet for 4 weeks. AP was induced by six hourly intraperitoneal injections of cerulein (50 µg/kg). Serum adipokine levels were measured, and pancreatitis severity was assessed histologically and by measuring pancreatic concentrations of interleukin-1 beta (IL-1ß), interleukin-6 (IL-6), myleoperoxidase (MPO), and monocyte chemoattractant protein-1 (MCP-1). RESULTS: Obese mice developed more severe pancreatitis than lean mice. Fish oil significantly decreased serum leptin (lean and obese) and increased serum adiponectin (lean only). Fish oil did not alter the baseline pancreatic inflammatory milieu, nor did it change histologic or biochemical pancreatitis severity. CONCLUSION: These data demonstrate that a diet rich in fish oil altered the adipokine milieu in lean and congenitally obese mice; however, fish oil did not improve pancreatitis severity induced with cerulein hyperstimulation.

Ezetimibe ameliorates cholecystosteatosis.

BACKGROUND: Cholecystosteatosis is the accumulation of gallbladder wall fats leading to decreased gallbladder emptying. Ezetimibe inhibits intestinal fat absorption and prevents murine gallstone formation. However, the influence of ezetimibe on gallbladder emptying and cholecystosteatosis has not been studied. Therefore, we tested the hypothesis that ezetimibe would improve gallbladder motility by preventing the buildup of fats in the gallbladder wall. METHODS: Forty lean female mice were fed either a control diet or a lithogenic diet for 6 weeks. Half of the mice on each diet received ezetimibe. At 11 weeks of age, all mice were fasted overnight and underwent gallbladder ultrasonography to determine ejection fraction. One week later, the mice were fasted and underwent cholecystectomy. Bile was examined for cholesterol crystals. The gallbladders were snap-frozen for lipid analysis. RESULTS: The lithogenic diet significantly (P < 0.05) increased serum cholesterol, biliary crystals, gallbladder wall cholesterol and cholesterol/phospholipid ratio, and decreased gallbladder ejection fraction. All of these abnormalities were reversed (P < 0.05) by the addition of ezetimibe to the diet. CONCLUSIONS: These data suggest that ezetimibe lowers serum cholesterol, prevents biliary crystals, and normalizes gallbladder wall fat and function. We conclude that ezetimibe ameliorates cholecystosteatosis and may be an effective agent for gallstone prevention.

High dietary carbohydrates decrease gallbladder volume and enhance cholesterol crystal formation.

BACKGROUND: Animal and human data suggest that a diet high in refined carbohydrates leads to gallstone formation. However, no data are available on the role of dietary carbohydrates on gallbladder volume or on cholesterol crystal formation. Therefore, we tested the hypothesis that a high carbohydrate diet would alter gallbladder volume and enhance cholesterol crystal formation. METHODS: At 8 weeks of age, 60 lean and 36 obese leptin-deficient female mice were fed a 45% carbohydrate diet while an equal number of lean and obese mice were fed a 75% carbohydrate diet for 4 weeks. All animals then underwent cholecystectomy, and gallbladder bile volume was recorded. Bile was pooled, filtered, and maintained in a water bath at 37 degrees C for 14 days. Birefringent cholesterol crystals in bile were counted daily; crystal observation time and crystal mass were determined. RESULTS: The crystal observation time was significantly shortened in both lean and obese mice on the 75% diet compared with their counterparts on the 45% diet. The crystal mass was significantly increased in the lean mice on the 75% diet compared with the 45% diet. Gallbladder volumes were significantly reduced in both lean and obese mice on the 75% diet compared with their counterparts on the 45% diet. CONCLUSIONS: These data suggest that a high carbohydrate diet decreases gallbladder volume, shortens cholesterol crystal observation time, and increases crystal mass. We conclude that dietary carbohydrates may play a role in cholesterol gallstone formation by altering biliary motility and by enhancing crystal formation.

Cholecystosteatosis: an explanation for increased cholecystectomy rates.

INTRODUCTION: Over the past decade, obesity has become epidemic, and the number of cholecystectomies as well as the percentage with acalculous cholecystitis have increased. We have recently reported that congenitally obese mice and lean mice fed a high fat diet have increased gallbladder wall lipids and poor gallbladder emptying. Therefore, we tested the hypothesis that compared to patients with a normal gallbladder, patients with both acalculous and calculous cholecystitis would have increased gallbladder wall fat. METHODS: Sixteen patients who underwent cholecystectomy for acalculous cholecystitis were identified. Sixteen nondiseased controls who underwent incidental cholecystectomy during surgery for liver or pancreatic disease and 16 diseased controls whose gallbladder was removed for chronic calculous cholecystitis were chosen to match the acalculous patients for gender and Body Mass Index. Pathology specimens were reviewed in a blinded fashion for gallbladder wall fat, thickness, and inflammation. RESULTS: Acalculous cholecystitis patients were younger (p < 0.01) than nondiseased or diseased controls. Gallbladder wall fat was significantly increased (p < 0.02) in the acalculous and calculous cholecystitis patients compared to the nondiseased controls. Gallbladder wall thickness (p < 0.02) and inflammatory score (p < 0.01) were highest in the calculous cholecystitis patients. CONCLUSIONS: These data suggest that compared to nondiseased controls, (1) patients with acalculous cholecystitis are younger and have increased gallbladder fat and (2) patients with calculous cholecystitis have increased gallbladder fat and inflammation. We conclude that increased gallbladder fat may lead to poor gallbladder emptying and biliary symptoms. Thus, cholecystosteatosis may explain, in part, the increased need for cholecystectomy and the higher percentage of these patients with acalculous cholecystitis.

Resistin-like molecule alpha reduces gallbladder optimal tension.

INTRODUCTION: Insulin resistance is associated with increased gallbladder volume and impaired gallbladder emptying. Resistin and resistin-like molecule alpha (RELM-alpha) are adipose-derived hormones that are believed to mediate insulin resistance. Therefore, we tested the hypothesis that administration of resistin or RELM-alpha would cause insulin resistance and diminish gallbladder contractility. METHODS: In two sequential studies 40 eight-week-old nondiabetic lean mice were fed a chow diet for 4 weeks. In Study A, 10 mice received 20 microg of resistin IP, while in Study B 10 mice received 20 microg of RELM-alpha IP for seven days. In each study, 10 control mice received an equal volume of saline IP for seven days. At 12 weeks animals were fasted and underwent cholecystectomy, and in vitro gallbladder response to neurotransmitters was determined. Serum resistin, RELM-alpha, glucose, and insulin levels were measured. HOMA index, a measure of insulin resistance, was calculated. RESULTS: RELM-alpha significantly increased HOMA index. RELM-alpha decreased gallbladder optimal tension, but did not alter responses to neurotransmitters. Resistin had no effect on HOMA index or on gallbladder optimal tension or response. CONCLUSION: These data suggest that in nondiabetic lean mice: 1) resistin does not alter insulin resistance or gallbladder optimal tension, but 2) RELM-alpha increases insulin resistance and reduces gallbladder optimal tension. Therefore, we concluded that RELM-alpha may play a role in insulin-resistance mediated gallbladder dysmotility.

Nonalcoholic Fatty gallbladder disease: the influence of diet in lean and obese mice.

The obesity epidemic has contributed to an increased prevalence of gallstones and a higher percentage of chronic acalculous cholecystitis. Obesity is associated with Type II diabetes and hyperlipidemia in murine models. In addition, we have previously demonstrated that serum glucose, insulin, cholesterol, and triglycerides correlated with gallbladder contractility in murine models. However, the relative role of insulin resistance and gallbladder fat infiltration in this phenomenon remain unclear. Therefore, we tested the hypothesis that gallbladder wall lipids are related to obesity and diet and are inversely correlated with gallbladder contractility. One hundred lean control (C7BL/6J) and 36 obese leptin-deficient (Lep(ob)) 8-week-old female mice were fed either a chow diet or a 1.0% cholesterol, 15% butterfat (high-lipid) diet for four weeks. Pooled gallbladders were then analyzed for free fatty acids (FFA), phospholipids (PL), total cholesterol (TC), and triglycerides (TG). Cholesterol/phospholipid ratios were then calculated. The Lep(ob) mice fed a chow diet had significantly higher (P < 0.01) gallbladder lipids than the three other groups. The lean mice that were fed a high-lipid diet had increased (P < 0.05) gallbladder TC compared to the lean mice on a chow diet. In addition, the cholesterol/phospholipid ratio was significantly increased (P < 0.01) in the lean mice fed a high-lipid diet compared to the other three groups. Finally, the high-lipid diet decreased gallbladder FFA (P < 0.01), PL (P = 0.08), and TC (P < 0.05) in Lep(ob) mice. These data suggest that (1) obese mice have increased gallbladder lipids; (2) a high-cholesterol, high-fat diet increases gallbladder lipids and the cholesterol/phospholipid ratio in lean mice; but (3) decreases gallbladder fatty acids, phospholipids, and cholesterol in obese mice. Prior studies have documented similarly decreased gallbladder response to neurotransmitters in obese mice on a chow diet, as well as lean and obese mice on a high-lipid diet. Therefore, we conclude that leptin-deficient obesity and/or a high-fat diet causes nonalcoholic fatty gallbladder disease, which is manifested by diminished gallbladder contractility.

Does adiponectin upregulation attenuate the severity of acute pancreatitis in obesity?

INTRODUCTION: Obesity is an independent risk factor for severe acute pancreatitis, though the mechanisms underlying this association are unknown. The powerful anti-inflammatory adipokine adiponectin is decreased in obesity. We recently showed that the severity of pancreatitis in obese mice is inversely related to circulating adiponectin levels, and therefore hypothesized that adiponectin upregulation would attenuate the severity of pancreatitis in obese mice. METHODS: Forty congenitally obese mice were studied. Seven days prior to study, 20 mice received a single tail vein injection of adenovirus expressing recombinant murine adiponectin (APN; 2 × 108 plaque forming unit (pfu)), and the remainder received a control adenoviral vector expressing ß-galactosidase (ß-gal; 2 × 108 pfu). Half of the mice in each group had pancreatitis induced by cerulein injection (50 mcg/kg IP hourly for 6 h). The other half received saline on the same schedule. Serum APN concentration and pancreatic tissue concentrations of interleukin (IL)-6, IL-1ß, and MCP-1 were measured by ELISA. Histologic pancreatitis score was calculated based on the degree of inflammation (0-4), edema (0-4), and vacuolization (0-4). Data were analyzed by ANOVA and Tukey's tests; p < 0.05 was considered significant. RESULTS: No difference in body weight was observed between groups. Serum APN was significantly upregulated in the APN group compared with the ß-gal group. Pancreatic tissue concentration of IL-6 was significantly decreased in the APN group compared with the ß-gal group. No change either in pancreatic tissue concentration of IL-1ß and MCP-1 or in the severity of histologic pancreatitis were observed. CONCLUSION: Adiponectin upregulation modulates the pancreatic cytokine milieu but does not attenuate pancreatitis in this model of mild acute pancreatitis.

The burden of incisional hernia in necrotizing pancreatitis: how can we improve?

BACKGROUND: Necrotizing pancreatitis (NP) patients frequently require pancreatic debridement, and have risk factors for incisional hernia (IH). However, no published data exist regarding the incidence of IH in NP. The aim of the current study was to define the incidence of and identify risk factors for developing IH after pancreatic debridement. METHODS: Hernia presence was determined by clinical examination and patient interview. Technical and clinical considerations were noted: type of incision, closure, suture material, age, body mass index (BMI), diabetes mellitus (DM), preoperative albumin, and number of operations. RESULTS: Sixty-three (42%) of 149 debrided patients with NP developed IH. IH patients were older (P<.05). No differences in surgical technique or clinical risk factors were seen between groups. CONCLUSION: The incidence of IH in NP patients requiring operative debridement is substantially higher than that in patients undergoing routine laparotomy. Innovative fascial closure techniques such as primary fascial buttress with nonsynthetic mesh should be considered.

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.

Leptin regulates gallbladder genes related to gallstone pathogenesis in leptin-deficient mice.

BACKGROUND: Little is known about the genetic factors that cause alterations in gallbladder motility, cholesterol crystal nucleation, biliary lipids, and, ultimately, cholesterol gallstones. Obese, leptin-deficient (Lep(ob)) mice have large gallbladder volumes with decreased contraction in vitro and are predisposed to cholesterol crystal formation. Leptin administration to these mice causes weight loss and restores gallbladder function. We hypothesize that administration of leptin to Lep(ob) mice would cause weight loss, decrease gallbladder volume, and change gallbladder genes related to gallbladder motility, nucleating factors, and lipid metabolism. STUDY DESIGN: Twenty-four 8-week-old Lep(ob) mice were fed a nonlithogenic diet for 4 weeks. Twelve mice received daily IP saline injections, and 12 received 5 mug/g recombinant leptin. Gallbladder mRNA was pooled and analyzed on murine genome microarray chips. Selected genes were confirmed by real-time polymerase chain reaction (PCR) in a second group of mice treated by the same protocol. RESULTS: Leptin-deficient mice given leptin had significant weight loss and reductions in gallbladder volume. These mice had upregulation of the leptin receptor (p = 0.007; PCR = 1.1-fold increase) but downregulation of leptin (p = 0.003; PCR = 13.5-fold decrease). Leptin upregulated the cholecystokinin A receptor (p < 0.001; PCR = 3.1-fold increase), acetylcholine beta2 receptor (p = 0.005), and the Ca+-calmodulin-dependent protein kinase (p = 0.002) genes. Leptin also altered immunoglobulin heavy chain 4 (p = 0.005; PCR = 17.7-fold increase), mucin 3 (p = 0.006), and carboxylesterase (p = 0.016; PCR = 2.5-fold decrease) genes. Leptin downregulated 3-hydroxy 3-methylglutaryl coenzyme A reductase (p = 0.006; PCR = 2.5-fold decrease) and LDL receptor (p = 0.003). CONCLUSIONS: Leptin modulates obesity and regulates gallbladder genes related to cholesterol gallstone pathogenesis.

Pioglitazone increases gallbladder volume in insulin-resistant obese mice.

BACKGROUND: Both obesity and diabetes are associated with an increased incidence of gallstones. Recent animal and human data from our laboratory suggest that insulin resistance is associated with increased gallbladder volume and/or impaired gallbladder emptying. Pioglitazone is a thiazolidinedione that has been shown to improve insulin resistance. Therefore, we tested the hypothesis that pioglitazone would improve insulin resistance, decrease resting gallbladder volume and improve gallbladder response to neurotransmitters in insulin-resistant obese mice fed a 25% carbohydrate diet. MATERIALS AND METHODS: Twenty eight-week-old insulin-resistant obese (Lep(ob)) mice fed a 25% carbohydrate diet for 4 weeks. Half of the animals had 0.3 g/kg pioglitazone added to their diet. At 12 weeks all animals were fasted and underwent cholecystectomy. Gallbladder volume and weight were measured, and fresh gallbladders were placed in a muscle bath to assess response to acetylcholine (ACh 10(-5)M), neuropeptide Y (NPY 10(-8,-7,-6)M) and cholecystokinin (CCK 10(-10,-9,-8,-7)M). Serum glucose and insulin were measured, and HOMA Index, a measure of insulin resistance, was calculated. RESULTS: Fasting serum insulin and HOMA Index were significantly decreased (P < 0.03), but gallbladder volume was significantly increased (P < 0.03) in the pioglitazone treated group. Pioglitazone did not alter gallbladder weight or response to ACh, NPY, or CCK. CONCLUSION: These data suggest that in insulin-resistant obese mice pioglitazone 1) lowers insulin-resistance, 2) increases resting gallbladder volume, and 3) does not alter gallbladder response to neurotransmitters. Therefore, we conclude that pioglitazone, while improving insulin resistance, paradoxically increases gallbladder volume and, thereby, may increase the propensity for gallstone formation by enhancing gallbladder stasis.