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M1771 The Prevalence of Insulin Resistance in Patients with Chronic Hepatitis C and B
disease, a relatively expensive method. There is a need to evaluate a simple and relatively inexpensive detection method for diagnosing fatty liver disease for at-risk patients. Once detected, patients can be properly managed and educated on the risks associated with the disease, including hepatitis and cirrhosis of the liver. Objective: To determine if liver ultrasound and liver enzymes can detect NAFLD in obese children. Methods: In a prospective study started in June 2005, obese children from two to eighteen years of age were enrolled and liver ultrasounds were performed to diagnose NAFLD. Most of the patients also had lipid profiles and serum transaminases. Exclusion criteria included metabolic disorders associated with liver disease, hepatotoxic medications, abdominal surgical procedures, total paraenteral nutrition, alcohol consumption and hepatitis. Results: Of 108 patients whose parents consented to the study, 48 patients completed liver ultrasounds. The BMI of each child was above the 95th percentile on age and gender adjusted growth charts. Liver ultrasound detected NAFLD in 67% of the patients. In the group of patients that completed both the laboratory tests and ultrasound, children with fatty liver have a higher BMI (p= 0.04), were older (p=0.02) and had elevated ALT levels (p=0.02). There were no statistical differences by t-test between the ultrasound and either ALT, LDL, Cholesterol, HDL and triglycerides. When a forward stepwise logistic regression analysis was done it showed that ALT, BMI and age were not good predictors of fatty liver on ultrasound. Discussion: NAFLD places obese children at risk for significant complications and they should be screened. Liver ultrasound detects NAFLD in the majority of obese children. Those with fatty liver detected on ultrasound were found to be older, with higher BMI's and ALT levels. Once children are recognized as being at risk, the pediatrician should screen, diagnose and treat the patient with NAFLD. Conclusion: Liver ultrasound is a promising screening test for detecting fatty liver disease in obese children. The ALT, BMI and age are not good predictors of detecting NAFLD by ultrasound. Further study needs to be done with a large number of patients to find out if indeed there is a correlation between ultrasound results and liver enzymes.
M1770 Serum Retinol-Binding Protein 4 (RBP4) Levels in Patients with Nonalcoholic Fatty Liver Disease Naim Alkhouri, Ariel E. Feldstein, Michael P. Berk Introduction: Nonalcoholic fatty liver disease (NAFLD) is considered the hepatic manifestation of the metabolic syndrome. Nonalcoholic steatohepatitis (NASH) is the most severe form. Insulin resistance (IR) is the pathophysiological hallmark of NAFLD. Recent data assigned RBP4 a key role in the pathogenesis of IR. Hepatocytes are the primary source of circulating RBP4 and adipose tissue has the second highest expression level. Changes in adipocyte derived RBP4 can have systemic effects on insulin sensitivity. Liver function may have a major impact on RBP4 levels. The aims of this study were to determine RBP4 levels in patients with biopsy proven NAFLD, and correlate these levels with histological features and metabolic phenotypes. Methods: Our cohort consisted of consecutive patients undergoing liver biopsy for clinical suspicion of NAFLD. Patients were subsequently divided into 3 groups according to their histological findings: fatty liver (n=16), borderline NASH (n=2) and NASH (n=33). The stage of fibrosis was measured using a 4-point scale. Only 2 patients showed borderline NASH and were excluded as no comparisons could be made. A total of 49 patients with NAFLD were used for the final statistical analysis. RBP4 was measured in triplicates by an ELISA (ALPCO Diagnostics) in blood samples obtained from patients at the time of biopsy. Demographic, clinical, and laboratory data were collected. Fasting labs included insulin, glucose, and lipid profile. The degree of IR was determined by HOMA. Results: Patient age (49.0 +/- 11.0) and sex (51.1 % males) did not differ significantly between the groups, whereas BMI and HOMA were higher in NASH patients compared with fatty liver patients. Serum RBP4 levels did not significantly correlate to BMI, HOMA, fasting glucose, or insulin levels. Moreover, RBP4 levels were lower in patients with NASH compared to those with fatty liver (21.4 mg/L and 27.1 mg/L respectively) although the difference did not reach statistical significance. A stepwise decrease in RBP4 levels from patients without fibrosis (26.0 mg/L) to patients with cirrhosis (14.1 mg/L) was noted (p value=0.03) Conclusions: Our study demonstrated that RBP4 levels were not elevated in NAFLD patients despite the presence of IR (higher HOMA). RBP4 levels were lower in NASH patients compared to fatty liver patients. More importantly an inverse correlation was found between the stage of fibrosis and RBP4 levels. Our findings suggest that liver injury due to NASH may result in decreased levels of RBP4. Lower RBP4 levels in obese patients with IR could potentially be used as a screening tool to identify patients at higher risk for developing NASH.
M1773 P2Y12 and the Components of the AKAP-Signaling Complex Are Localized to Cholangiocyte Cilia Providing Chemosensory Functions of These Organelles Anatoliy I. Masyuk, Jesus M. Banales, Sergio A. Gradilone, Tatyana V. Masyuk, Bing Q. Huang, Angela J. Stroope, Nicholas F. LaRusso Background. Cholangiocytes, the epithelial cells lining intrahepatic bile ducts, are the only epithelial cells in the liver that contain primary cilia, distinct organelles that extend from the apical plasma membrane into the ductal lumen where they function as mechano- and osmo-sensory organelles (Masyuk et al., 2006; Gradilone et al., 2007). In this study, we tested the hypothesis that cholangiocyte cilia are also chemosensory organelles which sense the concentration of biliary nucleotides (ATP and ADP) and transduce information into an intracellular response via ciliary-associated G-protein-coupled P2Y receptors and the cAMP signaling cascade. Methods. RT-PCR, Western blotting and immunofluorescence confocal microscopy were used to assess the expression of P2Y receptors, adenylyl cyclases (ACs) and downstream targets of cAMP [i.e., PKA (protein kinase A) and EPAC (an exchange protein directly activated by cAMP) and AKAPs (A-kinase anchoring proteins)] in rat cholangiocyte cilia. Microperfused rat intrahepatic bile ducts (IBD) and rat primary cultured cholangiocytes were used to test involvement of cholangiocyte cilia in the effects of ATP and ADP on intracellular cAMP levels. Results. Cholangiocyte cilia express P2Y12 but not P2Y2 and P2Y13. In addition, AC4, AC6, AC8, two PKA isoforms (i.e., PKA RII-alpha and PKA RIbeta) and EPAC1 are localized to cilia. Finally, cholangiocyte cilia express AKAP150, a protein known to form AKAP signaling complexes with AC, PKA, and EPAC. ATP and ADP, signaling molecules present in bile, affect cAMP levels in cholangiocytes in P2Y12- and ciliary-dependent manner. Luminal perfusion of IBDs with ATP-gS resulted in 2.6-fold increase (P<0.001) in cholangiocyte cAMP levels. In contrast, cAMP levels initially induced by forskolin, were reduced by ADP by 45±6% (P<0.05). The nucleotide-induced changes in cAMP levels were abolished by chloral hydrate (a reagent that removes cilia), and by siRNAs specific to P2Y12. Conclusion. Cholangiocyte cilia express P2Y12 and the components of the cAMP signaling cascade. Functionally, cholangiocyte cilia are chemosensory organelles that detect the levels of biliary nucleotides through ciliary associated P2Y12 and transmit information into the cell via the cAMP signaling cascade.
M1771 The Prevalence of Insulin Resistance in Patients with Chronic Hepatitis C and B Wael Soliman, Magdalena Kuczynski, I.George Fantus, Jenny Heathcote Background: The presence of insulin resistance (IR) may predict the subsequent development of diabetes. Diabetes is associated with chronic hepatitis C (CHC). The prevalence of IR in non-cirrhotic CHC patients has not been well assessed and similarly prevalence of IR in chronic hepatitis B (CHB) remains unknown. Aim: To assess the prevalence of IR defined as [Homeostasis Model assessment (HOMA-IR) ≥ 2.1] among treatment naïve, non-cirrhotic, non-diabetic (fasting serum glucose < 7mmol/l) patients with CHC and CHB (controls). Methods: IR measured by HOMA test [fasting insulin (microunits per milliliter) × fasting glucose (millimoles per liters) / 22.5] was determined in treatment naïve, non-cirrhotic (biopsy proven), non-diabetic patients with CHC and CHB. Patients with other diseases or those taking medications or alcohol (> 20 gm /day) were excluded. Demographic data (sex, race, age) and metabolic parameters [body mass index (BMI), waist circumference, lipid profile and free fatty acids] were collected in the patients studied. A series of t-tests (continuous) and chi-square test (categorical) were used to determine the differences between the CHC and CHB patient groups. A series of logistic regression analyses were performed to determine the independent predictors of IR (HOMA ≥ 2.1) among CHC and CHB. This study was approved by our hospital research ethics board. Results: IR status was determined in 102 CHC and 27 CHB patients. BMI, waist circumference, free fatty acids, histological activity index (HAI), hepatic fibrosis and steatosis scores were not significantly different between CHC and CHB patients (p=0.3092, p=0.1587, p=0.9486, p=0.4455, p=0.7871, p= 0.4079 respectively).The two groups were different in that male sex (p=0.0247) , Asian race (p<0.0001) and elevated serum cholesterol (p=0.0330) were more common in patients with CHB but there was no significant difference in the prevalence of IR (HOMA ≥ 2.1) among patients with CHC (38%) and CHB (30%) (p=0.4087). Multivariate analysis indicated that the prevalence of IR among patients with CHC was independently associated with BMI [p= 0.0054, overweight odds ratio (OR) = 6.78 & obesity OR = 17.13] and HAI (p=0.0344, activity grade 2 OR = 3.69), which was not the case in CHB. Conclusion: The prevalence of IR was 38% in CHC and 30% in CHB. BMI and HAI are independent risk factors for insulin resistance (HOMA ≥ 2.1) but only in CHC.
M1774 The Role of Th1 Immunity in Promoting Cholesterol Gallstone Formation in C57BL/6J Mice Kirk J. Maurer, Martin C. Carey, James G. Fox Introduction: T-cells are critical in murine cholesterol gallstone pathogenesis (Maurer et al. Gastroenterology 2007; 133:1304-15). Mice with functional T-cells that separate solid cholesterol crystals also display increases in Th1 (pro-inflammatory) cytokine transcription in their gallbladders. These data did not resolve whether Th1 immunity was a contributing factor to cholesterol gallstone pathogenesis or was the result. Here we analyze these possibilities. Methods: Male C57BL6/J mice lacking IL4 (Th1 prone; n=5), or IL12 (Th2 prone; n= 5) and wild-type C57BL6/J mice (n=13) were studied. All mice were infected with Helicobacter hepaticus and H. rodentium at 3-4 weeks-of-age. At eight-weeks of age mice were fed a lithogenic diet (containing 1% cholesterol and 0.5% cholic acid) for six weeks. Mice were euthanized and their biles were analyzed by direct and polarized light microscopy. Results: Th1 prone Il4-/- mice developed the highest prevalence of cholesterol monohydrate crystals (80%) and cholesterol gallstones (80%) whereas for Il12-/- mice, the corresponding values were 40% and 20% respectively. Wild-type mice displayed intermediate prevalences (62% for cholesterol monohydrate and 54% for cholesterol gallstones). Additionally, Il4-/- mice displayed a significant increase in mucin gel accumulation compared to Il12-/- mice (scores: 2.5 and 1.3 respectively; P<0.05). Conclusions: These results provide convincing evidence that Th1 immunity promotes murine cholesterol gallstone formation through an increased production of pro-nucleating mucin gel. Further, these data argue that local suppression of Th1 inflammation may protect against cholesterol gallstone formation.
M1772 The Use of Liver Ultrasound and Liver Enzymes in Detecting Non-Alcolohlic Fatty Liver Disease in Obese Children Hernando Lyons, Hannan Alsahlani, Alice Foster, Saleem Raza, Amina Husain, Rajam Samudrala, Karen Hagglund Background:Obesity in children is recognized as a public health problem associated with various complications, including Non-Alcoholic Fatty Liver Disease(NAFLD). Ultrasound, computed tomography, and magnetic resonance imaging can be used to detect NAFLD. There is only one U.S. study, which used hepatic MRI as a screening method for fatty liver
A-415
AGA Abstracts
AGA Abstracts
does not reduce ER stress or oxidative stress. Thus, betaine appears to be a possible treatment for NAFLD, although its mechanism of action is not through changes in oxidative stress or ER stress.
M1770 Serum Retinol-Binding Protein 4 (RBP4) Levels in Patients with Nonalcoholic Fatty Liver Disease Naim Alkhouri, Ariel E. Feldstein, Michael P. Berk Introduction: Nonalcoholic fatty liver disease (NAFLD) is considered the hepatic manifestation of the metabolic syndrome. Nonalcoholic steatohepatitis (NASH) is the most severe form. Insulin resistance (IR) is the pathophysiological hallmark of NAFLD. Recent data assigned RBP4 a key role in the pathogenesis of IR. Hepatocytes are the primary source of circulating RBP4 and adipose tissue has the second highest expression level. Changes in adipocyte derived RBP4 can have systemic effects on insulin sensitivity. Liver function may have a major impact on RBP4 levels. The aims of this study were to determine RBP4 levels in patients with biopsy proven NAFLD, and correlate these levels with histological features and metabolic phenotypes. Methods: Our cohort consisted of consecutive patients undergoing liver biopsy for clinical suspicion of NAFLD. Patients were subsequently divided into 3 groups according to their histological findings: fatty liver (n=16), borderline NASH (n=2) and NASH (n=33). The stage of fibrosis was measured using a 4-point scale. Only 2 patients showed borderline NASH and were excluded as no comparisons could be made. A total of 49 patients with NAFLD were used for the final statistical analysis. RBP4 was measured in triplicates by an ELISA (ALPCO Diagnostics) in blood samples obtained from patients at the time of biopsy. Demographic, clinical, and laboratory data were collected. Fasting labs included insulin, glucose, and lipid profile. The degree of IR was determined by HOMA. Results: Patient age (49.0 +/- 11.0) and sex (51.1 % males) did not differ significantly between the groups, whereas BMI and HOMA were higher in NASH patients compared with fatty liver patients. Serum RBP4 levels did not significantly correlate to BMI, HOMA, fasting glucose, or insulin levels. Moreover, RBP4 levels were lower in patients with NASH compared to those with fatty liver (21.4 mg/L and 27.1 mg/L respectively) although the difference did not reach statistical significance. A stepwise decrease in RBP4 levels from patients without fibrosis (26.0 mg/L) to patients with cirrhosis (14.1 mg/L) was noted (p value=0.03) Conclusions: Our study demonstrated that RBP4 levels were not elevated in NAFLD patients despite the presence of IR (higher HOMA). RBP4 levels were lower in NASH patients compared to fatty liver patients. More importantly an inverse correlation was found between the stage of fibrosis and RBP4 levels. Our findings suggest that liver injury due to NASH may result in decreased levels of RBP4. Lower RBP4 levels in obese patients with IR could potentially be used as a screening tool to identify patients at higher risk for developing NASH.
M1773 P2Y12 and the Components of the AKAP-Signaling Complex Are Localized to Cholangiocyte Cilia Providing Chemosensory Functions of These Organelles Anatoliy I. Masyuk, Jesus M. Banales, Sergio A. Gradilone, Tatyana V. Masyuk, Bing Q. Huang, Angela J. Stroope, Nicholas F. LaRusso Background. Cholangiocytes, the epithelial cells lining intrahepatic bile ducts, are the only epithelial cells in the liver that contain primary cilia, distinct organelles that extend from the apical plasma membrane into the ductal lumen where they function as mechano- and osmo-sensory organelles (Masyuk et al., 2006; Gradilone et al., 2007). In this study, we tested the hypothesis that cholangiocyte cilia are also chemosensory organelles which sense the concentration of biliary nucleotides (ATP and ADP) and transduce information into an intracellular response via ciliary-associated G-protein-coupled P2Y receptors and the cAMP signaling cascade. Methods. RT-PCR, Western blotting and immunofluorescence confocal microscopy were used to assess the expression of P2Y receptors, adenylyl cyclases (ACs) and downstream targets of cAMP [i.e., PKA (protein kinase A) and EPAC (an exchange protein directly activated by cAMP) and AKAPs (A-kinase anchoring proteins)] in rat cholangiocyte cilia. Microperfused rat intrahepatic bile ducts (IBD) and rat primary cultured cholangiocytes were used to test involvement of cholangiocyte cilia in the effects of ATP and ADP on intracellular cAMP levels. Results. Cholangiocyte cilia express P2Y12 but not P2Y2 and P2Y13. In addition, AC4, AC6, AC8, two PKA isoforms (i.e., PKA RII-alpha and PKA RIbeta) and EPAC1 are localized to cilia. Finally, cholangiocyte cilia express AKAP150, a protein known to form AKAP signaling complexes with AC, PKA, and EPAC. ATP and ADP, signaling molecules present in bile, affect cAMP levels in cholangiocytes in P2Y12- and ciliary-dependent manner. Luminal perfusion of IBDs with ATP-gS resulted in 2.6-fold increase (P<0.001) in cholangiocyte cAMP levels. In contrast, cAMP levels initially induced by forskolin, were reduced by ADP by 45±6% (P<0.05). The nucleotide-induced changes in cAMP levels were abolished by chloral hydrate (a reagent that removes cilia), and by siRNAs specific to P2Y12. Conclusion. Cholangiocyte cilia express P2Y12 and the components of the cAMP signaling cascade. Functionally, cholangiocyte cilia are chemosensory organelles that detect the levels of biliary nucleotides through ciliary associated P2Y12 and transmit information into the cell via the cAMP signaling cascade.
M1771 The Prevalence of Insulin Resistance in Patients with Chronic Hepatitis C and B Wael Soliman, Magdalena Kuczynski, I.George Fantus, Jenny Heathcote Background: The presence of insulin resistance (IR) may predict the subsequent development of diabetes. Diabetes is associated with chronic hepatitis C (CHC). The prevalence of IR in non-cirrhotic CHC patients has not been well assessed and similarly prevalence of IR in chronic hepatitis B (CHB) remains unknown. Aim: To assess the prevalence of IR defined as [Homeostasis Model assessment (HOMA-IR) ≥ 2.1] among treatment naïve, non-cirrhotic, non-diabetic (fasting serum glucose < 7mmol/l) patients with CHC and CHB (controls). Methods: IR measured by HOMA test [fasting insulin (microunits per milliliter) × fasting glucose (millimoles per liters) / 22.5] was determined in treatment naïve, non-cirrhotic (biopsy proven), non-diabetic patients with CHC and CHB. Patients with other diseases or those taking medications or alcohol (> 20 gm /day) were excluded. Demographic data (sex, race, age) and metabolic parameters [body mass index (BMI), waist circumference, lipid profile and free fatty acids] were collected in the patients studied. A series of t-tests (continuous) and chi-square test (categorical) were used to determine the differences between the CHC and CHB patient groups. A series of logistic regression analyses were performed to determine the independent predictors of IR (HOMA ≥ 2.1) among CHC and CHB. This study was approved by our hospital research ethics board. Results: IR status was determined in 102 CHC and 27 CHB patients. BMI, waist circumference, free fatty acids, histological activity index (HAI), hepatic fibrosis and steatosis scores were not significantly different between CHC and CHB patients (p=0.3092, p=0.1587, p=0.9486, p=0.4455, p=0.7871, p= 0.4079 respectively).The two groups were different in that male sex (p=0.0247) , Asian race (p<0.0001) and elevated serum cholesterol (p=0.0330) were more common in patients with CHB but there was no significant difference in the prevalence of IR (HOMA ≥ 2.1) among patients with CHC (38%) and CHB (30%) (p=0.4087). Multivariate analysis indicated that the prevalence of IR among patients with CHC was independently associated with BMI [p= 0.0054, overweight odds ratio (OR) = 6.78 & obesity OR = 17.13] and HAI (p=0.0344, activity grade 2 OR = 3.69), which was not the case in CHB. Conclusion: The prevalence of IR was 38% in CHC and 30% in CHB. BMI and HAI are independent risk factors for insulin resistance (HOMA ≥ 2.1) but only in CHC.
M1774 The Role of Th1 Immunity in Promoting Cholesterol Gallstone Formation in C57BL/6J Mice Kirk J. Maurer, Martin C. Carey, James G. Fox Introduction: T-cells are critical in murine cholesterol gallstone pathogenesis (Maurer et al. Gastroenterology 2007; 133:1304-15). Mice with functional T-cells that separate solid cholesterol crystals also display increases in Th1 (pro-inflammatory) cytokine transcription in their gallbladders. These data did not resolve whether Th1 immunity was a contributing factor to cholesterol gallstone pathogenesis or was the result. Here we analyze these possibilities. Methods: Male C57BL6/J mice lacking IL4 (Th1 prone; n=5), or IL12 (Th2 prone; n= 5) and wild-type C57BL6/J mice (n=13) were studied. All mice were infected with Helicobacter hepaticus and H. rodentium at 3-4 weeks-of-age. At eight-weeks of age mice were fed a lithogenic diet (containing 1% cholesterol and 0.5% cholic acid) for six weeks. Mice were euthanized and their biles were analyzed by direct and polarized light microscopy. Results: Th1 prone Il4-/- mice developed the highest prevalence of cholesterol monohydrate crystals (80%) and cholesterol gallstones (80%) whereas for Il12-/- mice, the corresponding values were 40% and 20% respectively. Wild-type mice displayed intermediate prevalences (62% for cholesterol monohydrate and 54% for cholesterol gallstones). Additionally, Il4-/- mice displayed a significant increase in mucin gel accumulation compared to Il12-/- mice (scores: 2.5 and 1.3 respectively; P<0.05). Conclusions: These results provide convincing evidence that Th1 immunity promotes murine cholesterol gallstone formation through an increased production of pro-nucleating mucin gel. Further, these data argue that local suppression of Th1 inflammation may protect against cholesterol gallstone formation.
M1772 The Use of Liver Ultrasound and Liver Enzymes in Detecting Non-Alcolohlic Fatty Liver Disease in Obese Children Hernando Lyons, Hannan Alsahlani, Alice Foster, Saleem Raza, Amina Husain, Rajam Samudrala, Karen Hagglund Background:Obesity in children is recognized as a public health problem associated with various complications, including Non-Alcoholic Fatty Liver Disease(NAFLD). Ultrasound, computed tomography, and magnetic resonance imaging can be used to detect NAFLD. There is only one U.S. study, which used hepatic MRI as a screening method for fatty liver
A-415
AGA Abstracts
AGA Abstracts
does not reduce ER stress or oxidative stress. Thus, betaine appears to be a possible treatment for NAFLD, although its mechanism of action is not through changes in oxidative stress or ER stress.