Cholesterol gallstone disease

With a prevalence of 10-15% in adults in Europe and the USA, gallstones are the most common digestive disease needing admission to hospital in the West. The interplay between interprandial and postprandial physiological responses to endogenous and dietary lipids underscores the importance of coordinated hepatobiliary and gastrointestinal functions to prevent crystallisation and precipitation of excess biliary cholesterol. Indeed, identifying the metabolic and transcriptional pathways that drive the regulation of biliary lipid secretion has been a major achievement in the field. We highlight scientific advances in protein and gene regulation of cholesterol absorption, synthesis, and catabolism, and biliary lipid secretion with respect to the pathogenesis of cholesterol gallstone disease. We discuss the physical-chemical mechanisms of gallstone formation in bile and the active role of the gallbladder and the intestine. We also discuss gaps in our knowledge of the pathogenesis of gallstone formation and the potential for gene targeting in therapy.

Gut Microbiota and Short Chain Fatty Acids: Implications in Glucose Homeostasis

Gut microbiota encompasses a wide variety of commensal microorganisms consisting of trillions of bacteria, fungi, and viruses. This microbial population coexists in symbiosis with the host, and related metabolites have profound effects on human health. In this respect, gut microbiota plays a pivotal role in the regulation of metabolic, endocrine, and immune functions. Bacterial metabolites include the short chain fatty acids (SCFAs) acetate (C2), propionate (C3), and butyrate (C4), which are the most abundant SCFAs in the human body and the most abundant anions in the colon. SCFAs are made from fermentation of dietary fiber and resistant starch in the gut. They modulate several metabolic pathways and are involved in obesity, insulin resistance, and type 2 diabetes. Thus, diet might influence gut microbiota composition and activity, SCFAs production, and metabolic effects. In this narrative review, we discuss the relevant research focusing on the relationship between gut microbiota, SCFAs, and glucose metabolism.

Intestinal Barrier and Permeability in Health, Obesity and NAFLD

The largest surface of the human body exposed to the external environment is the gut. At this level, the intestinal barrier includes luminal microbes, the mucin layer, gastrointestinal motility and secretion, enterocytes, immune cells, gut vascular barrier, and liver barrier. A healthy intestinal barrier is characterized by the selective permeability of nutrients, metabolites, water, and bacterial products, and processes are governed by cellular, neural, immune, and hormonal factors. Disrupted gut permeability (leaky gut syndrome) can represent a predisposing or aggravating condition in obesity and the metabolically associated liver steatosis (nonalcoholic fatty liver disease, NAFLD). In what follows, we describe the morphological-functional features of the intestinal barrier, the role of major modifiers of the intestinal barrier, and discuss the recent evidence pointing to the key role of intestinal permeability in obesity/NAFLD.

COVID-19 and non-alcoholic fatty liver disease: Two intersecting pandemics

BACKGROUND

Initial evidence from China suggests that most vulnerable subjects to COVID-19 infection suffer from pre-existing illness, including metabolic abnormalities. The pandemic characteristics and high-lethality rate of COVID-19 infection have raised concerns about interactions between virus pathobiology and components of the metabolic syndrome.

METHODS

We harmonized the information from the recent existing literature on COVID-19 acute pandemic and mechanisms of damage in non-alcoholic fatty liver disease (NAFLD), as an example of chronic (non-communicable) metabolic pandemic.

RESULTS

COVID-19-infected patients are more fragile with underlying metabolic illness, including hypertension, cardiovascular disease, type 2 diabetes, chronic lung diseases (e.g. asthma, chronic obstructive pulmonary disease and emphysema) and metabolic syndrome. During metabolic abnormalities, expansion of metabolically active fat ('overfat condition') parallels chronic inflammatory changes, development of insulin resistance and accumulation of fat in configuring NAFLD. The deleterious interplay of inflammatory pathways chronically active in NAFLD and acutely in COVID-19-infected patients, can explain liver damage in a subgroup of patients and might condition a worse outcome in metabolically compromised NAFLD patients. In a subgroup of patients with NAFLD, the underlying liver fibrosis might represent an additional and independent risk factor for severe COVID-19 illness, irrespective of metabolic comorbidities.

CONCLUSIONS

NAFLD can play a role in the outcome of COVID-19 illness due to frequent association with comorbidities. Initial evidences suggest that increased liver fibrosis in NAFLD might affect COVID-19 outcome. In addition, long-term monitoring of post-COVID-19 NAFLD patients is advisable, to document further deterioration of liver damage. Further studies are required in this field.

Coordinate regulation of gallbladder motor function in the gut-liver axis

Gallstones are one of the most common digestive diseases with an estimated prevalence of 10%-15% in adults living in the western world, where cholesterol-enriched gallstones represent 75%-80% of all gallstones. In cholesterol gallstone disease, the gallbladder becomes the target organ of a complex metabolic disease. Indeed, a fine coordinated hepatobiliary and gastrointestinal function, including gallbladder motility in the fasting and postprandial state, is of crucial importance to prevent crystallization and precipitation of excess cholesterol in gallbladder bile. Also, gallbladder itself plays a physiopathological role in biliary lipid absorption. Here, we present a comprehensive view on the regulation of gallbladder motor function by focusing on recent discoveries in animal and human studies, and we discuss the role of the gallbladder in the pathogenesis of gallstone formation.

Hepatic consequences of COVID-19 infection. Lapping or biting?

The outbreak of coronavirus disease 2019 (COVID-19) starting last December in China placed emphasis on liver involvement during infection. This review discusses the underlying mechanisms linking COVID-19 to liver dysfunction, according to recent available information, while waiting further studies. The manifestations of liver damage are usually mild (moderately elevated serum aspartate aminotransferase activities), and generally asymptomatic. Few patients can still develop severe liver problems, and therapeutic options can be limited. Liver dysfunction may affect about one-third of the patients, with prevalence greater in men than women, and in elderly. Mechanisms of damage are complex and include direct cholangiocyte damage and other coexisting conditions such as the use of antiviral drugs, systemic inflammatory response, respiratory distress syndrome-induced hypoxia, sepsis, and multiple organ dysfunction. During new COVID-19 infections, liver injury may be observed. If liver involvement appears during COVID-19 infection, however, attention is required. This is particularly true if patients are older or have a pre-existing history of liver diseases. During COVID-19 infection, the onset of liver damage impairs the prognosis, and hospital stay is longer.

Liver breath tests non-invasively predict higher stages of non-alcoholic steatohepatitis

Effectively assessing subtle hepatic metabolic functions by novel non-invasive tests might be of clinical utility in scoring NAFLD (non-alcoholic fatty liver disease) and in identifying altered metabolic pathways. The present study was conducted on 39 (20 lean and 19 obese) hypertransaminasemic patients with histologically proven NAFLD {ranging from simple steatosis to severe steatohepatitis [NASH (non-alcoholic steatohepatitis)] and fibrosis} and 28 (20 lean and eight overweight) healthy controls, who underwent stable isotope breath testing ([(13)C]methacetin and [(13)C]ketoisocaproate) for microsomal and mitochondrial liver function in relation to histology, serum hyaluronate, as a marker of liver fibrosis, and body size. Compared with healthy subjects and patients with simple steatosis, NASH patients had enhanced methacetin demethylation (P=0.001), but decreased (P=0.001) and delayed (P=0.006) ketoisocaproate decarboxylation, which was inversely related (P=0.001) to the degree of histological fibrosis (r=-0.701), serum hyaluronate (r=-0.644) and body size (r=-0.485). Ketoisocaproate decarboxylation was impaired further in obese patients with NASH, but not in patients with simple steatosis and in overweight controls. NASH and insulin resistance were independently associated with an abnormal ketoisocaproate breath test (P=0.001). The cut-off value of 9.6% cumulative expired (13)CO(2) for ketoisocaproate at 60 min was associated with the highest prediction (positive predictive value, 0.90; negative predictive value, 0.73) for NASH, yielding an overall sensitivity of 68% and specificity of 94%. In conclusion, both microsomal and mitochondrial functions are disturbed in NASH. Therefore stable isotope breath tests may usefully contribute to a better and non-invasive characterization of patients with NAFLD.

Gallstone disease: Symptoms and diagnosis of gallbladder stones

The clinical aspects and the diagnostic features of gallstone disease are described. The natural history of silent gallstones is overviewed, and the risk of developing symptoms and complications is also discussed. The importance of colicky pain as a specific gallstone symptom is highlighted, and the role of both laboratory tests and diagnostic investigations for differential diagnosis is discussed. Finally, we describe the diagnostic features of gallbladder stone disease, including indications, sensitivity, specificity, and limitations of different test investigations under special circumstances.

Pan-enteric dysmotility, impaired quality of life and alexithymia in a large group of patients meeting ROME II criteria for irritable bowel syndrome

AIM

Psychological factors, altered motility and sensation disorders of the intestine can be variably associated with irritable bowel syndrome (IBS). Such aspects have not been investigated simultaneously. The aim of this paper was to evaluate gastrointestinal motility and symptoms, psychological spectrum and quality of life in a large group of IBS patients in southern Italy.

METHODS

One hundred IBS patients (F:M=73:27, age 48+/-2 years, mean+/-SE) fulfilling ROME II criteria matched with 100 healthy subjects (F:M=70:30, 45+/-2 years). Dyspepsia, bowel habit, alexithymia, psycho-affective profile and quality of life were assessed using specific questionnaires. Basally and postprandially, changes in gallbladder volumes and antral areas after liquid meal and orocaecal transit time (OCTT) were measured respectively by ultrasonography and H(2)-breath test. Appetite, satiety, fullness, nausea, and epigastric pain/discomfort were monitored using visual-analogue scales.

RESULTS

Compared with controls, IBS patients had increased dyspepsia (score 12.6+/-0.7 vs 5.1+/-0.2, P<0.0001), weekly bowel movements (12.3+/-0.4 vs 5.5+/-0.2, P<0.00001, comparable stool shape), alexithymia (score 59.1+/-1.1 vs 40.5+/-1.0, P=0.001), poor quality of life and psycho-affective profile. IBS patients had normal gallbladder emptying, but delayed gastric emptying (T50: 35.5+/-1.0 vs 26.1+/-0.6 min, P=0.00001) and OCTT (163.0+/-5.4 vs 96.6+/-1.8 min, P=0.00001). Fullness, nausea, and epigastric pain/discomfort were greater in IBS than in controls.

CONCLUSION

ROME II IBS patients have a pan-enteric dysmotility with frequent dyspepsia, associated with psychological morbidity and greatly impaired quality of life. The presence of alexithymia, a stable trait, is a novel finding of potential interest to detect subgroups of IBS patients with different patterns recovered after therapy.

Nonalcoholic steatohepatitis: recent advances from experimental models to clinical management

A condition defined as nonalcoholic fatty liver disease (NAFLD) is frequently found in humans. Deemed as a benign condition until recently, more emphasis is now put on the potential harmful evolution of the inflammatory form, that is, nonalcoholic steatohepatitis (NASH), toward end-stage liver disease. This review highlights the major morphologic and pathophysiological features of NASH. The link between experimental biochemical findings in animal models and clinical and therapeutic approaches in humans is discussed. Once all the other causes of persistent elevation of serum transaminase levels have been excluded, the diagnosis of NASH can be only confirmed by liver histology. Other noninvasive diagnostic tools, however, are being investigated to assess specific subcellular functions and to allow the follow-up of patients at higher risk for major liver dysfunction. A better understanding of various pathogenic aspects of NASH will help in identifying potential therapeutic approaches in these patients.

Gallbladder motor function in gallstone patients: sonographic and in vitro studies on the role of gallstones, smooth muscle function and gallbladder wall inflammation

Gallbladder motility was studied by ultrasound in 100 healthy adult volunteers and 150 gallstone patients, in a subgroup of whom gallstone burden, type and number, gallbladder histology and tensiometric responses of gallbladder strips to cholecystokinin octapeptide were evaluated. Patients were divided into contractors (n = 108) and hypocontractors (n = 42), according to their gallbladder motility pattern in vivo. Contractors showed slower gallbladder emptying and increased fasting and postprandial residual volumes, although the ejected amount of bile was greater than that of controls (20.2 +/- SEM 1.1 vs 16.0 +/- 0.7 ml; p < 0.001). In contrast, hypocontractors exhibited slower and less complete gallbladder emptying than controls with a reduction in the absolute amount of ejected bile. Although gallbladder wall inflammation was mild and comparable in specimens from both groups of patients, the thickness of the muscular layer was greater in hypocontractors than in contractors (1073 +/- 76 vs 745 +/- 75 microns, p < 0.01) and related inversely to postprandial ejected volume (r = -0.42; p < 0.03; n = 32) but positively to gallstone volume (r = 0.40; p < 0.03; n = 32). Compared to contractors, gall-bladder muscle strips of hypocontractors exhibited a decrease in frequency and amplitude of spontaneous contraction and in maximal stress and receptor sensitivity to cholecystokinin octapeptide (0.1 nM-1 microM). Postprandial gallbladder evaculation was unaffected by stone number, and by the presence or absence of stone calcification. Gallstone volume was larger in hypocontractors (19.4 +/- 3.0 ml vs 9.6 +/- 0.9 ml, p < 0.001) than contractors. The comparison of in vitro contractility patterns between cholesterol, mixed and pigment stone patients showed a more severe defect in patients with cholesterol and mixed stones than in those with pigment calculi. In conclusion, in gallstone patients: (i) gallbladder motor dysfunction manifests mainly with increased fasting and postprandial residual volumes in contractors and with markedly increased postprandial residual volumes and decreased gallbladder emptying in hypocontractors; (ii) gallbladder kinetics seem to be influenced by stone volume and cholesterol content of calculi but not stone number, calcification or mild chronic cholecystitis; (iii) a form of hypertrophic leiomyopathy is observed in gallstone patients with the most impaired gallbladder motor function.

Curcumin and Fennel Essential Oil Improve Symptoms and Quality of Life in Patients with Irritable Bowel Syndrome

BACKGROUND AND AIMS

Irritable Bowel Syndrome (IBS) patients still require effective treatment. The anti-inflammatory property of curcumin and the antispasmodic and carminative effect of fennel suggests that combination of these nutraceutical compounds would be useful in functional bowel disorders including IBS. We assessed the efficacy and tolerability of a combination of curcumin and fennel essential oil (CU-FEO) in IBS symptoms relief.

METHODS

121 patients with mild-to-moderate symptoms of IBS defined by an Irritable Bowel Syndrome- symptom severity score (IBS-SSS) 100-300 and abdominal pain score 30-70 on a 100 mm Visual Analogue Scale (VAS), were randomly assigned to CU-FEO or placebo (2 capsules b.d. for 30 days). Primary endpoint was the mean decrease of IBS-SSS at the end of the treatment corrected for the mean baseline score (relative decrease). The impact of the treatment on quality of life was assessed through IBS-QoL questionnaire.

RESULTS

CU-FEO was safe, well-tolerated and induced symptom relief in patients with IBS; a significant decrease in the mean relative IBS-SSS was observed after 30 days of treatment (50.05 +/- 28.85% vs 26.12 +/- 30.62%, P<0.001). This result matched the reduction of abdominal pain and all the other symptoms of IBS-SSS. The percentage of symptom-free patients was significantly higher in the CU-FEO than in the placebo group (25.9% vs. 6.8%, P = 0.005). All domains of IBS-QoL improved consistently.

CONCLUSION

CU-FEO significantly improved symptoms and quality of life in IBS patients over 30 days.

Management of gallstones and its related complications

The majority of gallstone patients remain asymptomatic; however, interest toward the gallstone disease is continuing because of the high worldwide prevalence and management costs and the development of gallstone symptoms and complications. For cholesterol gallstone disease, moreover, a strong link exists between this disease and highly prevalent metabolic disorders such as obesity, dyslipidemia, type 2 diabetes, hyperinsulinemia, hypertriglyceridemia and the metabolic syndrome. Information on the natural history as well as the diagnostic, surgical (mainly laparoscopic cholecystectomy) and medical tools available to facilitate adequate management of cholelithiasis and its complications are, therefore, crucial to prevent the negative outcomes of gallstone disease. Moreover, some risk factors for gallstone disease are modifiable and some preventive strategies have become necessary to reduce the onset and the severity of complications.

Therapy of gallstone disease: What it was, what it is, what it will be

Cholesterol gallstone disease is a common clinical condition influenced by genetic factors, increasing age, female gender, and metabolic factors. Although laparoscopic cholecystectomy is currently considered the gold standard in treating patients with symptomatic gallstones, new perspectives regarding medical therapy of cholelithiasis are currently under discussion, also taking into account the pathogenesis of gallstones, the natural history of the disease and the analysis of the overall costs of therapy. A careful selection of patients may lead to successful non-surgical therapy in symptomatic subjects with a functioning gallbladder harboring small radiolucent stones. The classical oral litholysis by ursodeoxycholic acid has been recently paralleled by new experimental observations, suggesting that cholesterol-lowering agents which inhibit cholesterol synthesis (statins) or intestinal cholesterol absorption (ezetimibe), or drugs acting on specific nuclear receptors involved in cholesterol and bile acid homeostasis, might be proposed as additional approaches for treating cholesterol gallstones. In this review we discuss old, recent and future perspectives on medical treatment of cholesterol cholelithiasis.

Gallbladder motility and cholesterol crystallization in bile from patients with pigment and cholesterol gallstones

BACKGROUND

Little is known about gallbladder motility in patients with black pigment stones when compared to cholesterol gallstone patients, or about their relationship to biliary composition, crystallization and stone characteristics.

DESIGN

Fasting and postprandial gallbladder volumes were studied by ultrasonography in 49 gallstone patients with pigment (n = 14) or cholesterol (n = 35) stones and 30 healthy controls. After cholecystectomy stone composition, gallbladder wall inflammation, cholesterol saturation index and appearance of platelike cholesterol crystals in bile were evaluated in gallstone patients.

RESULTS

Fasting gallbladder volume was significantly (P < 0.05) increased in cholesterol stone patients (31.7 +/- 1.9 mL) but not in pigment stone patients (21.9 +/- 3.1 mL), compared to controls (21.0 +/- 1.5 mL). Postprandial emptying was delayed in patients (half-emptying time: 31 +/- 2 min, 35 +/- 3 min, 24 +/- 2 min in cholesterol stone patients, pigment stone patients and controls, respectively, P < 0.05) and incomplete (residual volume: 43.2 +/- 2.7%, 40.0 +/- 4.3%, 15.8 +/- 1.6% min in cholesterol stone patients, pigment stone patients and controls, respectively, P < 0.05). The inflammation of the gallbladder wall was mild or absent in all cases. Biliary cholesterol saturation index was 152.3 +/- 8.5% and 92.9 +/- 4.8% in patients with cholesterol and pigment stones, respectively (P < 0.01). Whereas cholesterol crystals never appeared during 21 days in biles from patients with pigment stones, crystal observation time in patients with cholesterol gallstone was 5 days (median) and was significantly shorter in patients with multiple (4 days) than in patients with solitary (12 days) cholesterol stones (P = 0.0019).

CONCLUSIONS

Patients with black pigment stones who do not have excess cholesterol and do not grow cholesterol crystals in bile have decreased gallbladder emptying, although to a lesser extent than patients with cholesterol stones. Thus, gallbladder stasis is likely to put a subset of subjects at risk for the formation of pigment gallstones, and pathogenic mechanisms need to be further investigated.

Smooth muscle function and dysfunction in gallbladder disease

The gallbladder epithelium and smooth muscle layer are exposed to concentrated biliary solutes, including cholesterol and potentially toxic hydrophobic bile salts, which are able to influence muscle contraction. Physiologically, gallbladder tone is regulated by spontaneous muscle activity, hormones, and neurotransmitters released into the muscle from intrinsic neurons and extrinsic sympathetic nerves. Methods to explore gallbladder smooth muscle function in vitro include cholecystokinin (CCK) receptor-binding studies and contractility studies. In human and animal models, studies have focused on cellular and molecular events in health and disease, and in vitro findings mirror in vivo events. The interplay between contraction and relaxation of the gallbladder muscularis leads in vivo to appropriate gallbladder emptying and refilling during fasting and postprandially. Defective smooth muscle contractility and/or relaxation are found in cholesterol stone-containing gallbladders, featuring a type of gallbladder leiomyopathy; defects of CCKA receptors and signal transduction may coexist with abnormal responses to oxidative stress and inflammatory mediators. Abnormal smooth musculature contractility, impaired gallbladder motility, and increased stasis are key factors in the pathogenesis of cholesterol gallstones.

Current pharmacological treatment of nonalcoholic fatty liver

Nonalcoholic fatty liver disease (NAFLD) is a frequent and potentially progressive chronic liver disease that occurs in subjects who do not abuse alcohol. NAFLD is often associated with obesity, metabolic syndrome and insulin resistance and its more aggressive form, nonalcoholic steatohepatitis (NASH) is a major cause of cryptogenic cirrhosis. NAFLD/NASH are commonly detected because of elevated serum aminotransferase levels, ultrasonographic fatty liver and, at liver histology, steatosis, inflammation, and occasionally fibrosis that may progress to cirrhosis. No established treatment exists for this potentially serious disorder. Current management of NAFLD/NASH is largely conservative and includes diet regimen, aerobic exercise, and interventions towards the associated metabolic abnormalities. The main concern is therefore to decrease liver steatosis and its progression toward steatohepatitis and fibrosis, and the risk of "cryptogenic" cirrhosis. Among the most promising medications, weight reducing drugs, insulin sensitizers and lipid-lowering agents, antioxidants, bile salts, co-factors increasing the mitochondrial transport of fatty acids are being considered. Among them, thiazolidinediones are the most promising drug family that act by activating PPARgamma nuclear receptors and by regulating both microsomal and peroxisomal lipid oxidative pathways. Pharmacological treatment of obesity and probiotics should be considered as potential therapeutic options. In this review, after summarizing the general background on fatty liver, the most current and attractive pharmacological approaches to the problem of NAFLD/NASH are discussed.

Aquaporins in the hepatobiliary tract. Which, where and what they do in health and disease

The biological importance of the aquaporin family of water channels was recently acknowledged by the 2003 Nobel Prize for Chemistry awarded to the discovering scientist Peter Agre. Among the pleiotropic roles exerted by aquaporins in nature in both health and disease, the review addresses the latest acquisitions about the expression and regulation, as well as physiology and pathophysiology of aquaporins in the hepatobiliary tract. Of note, at least seven out of the thirteen mammalian aquaporins are expressed in the liver, bile ducts and gallbladder. Aquaporins are essential for bile water secretion and reabsorption, as well as for plasma glycerol uptake by the hepatocyte and its conversion to glucose during starvation. Novel data are emerging regarding the physio-pathological involvement of aquaporins in multiple diseases such as cholestases, liver cirrhosis, obesity and insulin resistance, fatty liver, gallstone formation and even microparasite invasion of intrahepatic bile ducts. This body of knowledge represents the mainstay of present and future research in a rapidly expanding field.

Irritable bowel syndrome and diet

Irritable bowel syndrome (IBS) is a chronic functional disorder of the gastrointestinal tract and is one of the most commonly diagnosed gastrointestinal diseases. The impact of IBS on the general population is large due to its high prevalence, suboptimal medical treatments and significant economic burden. The pathophysiology of IBS is complex and treatments are often symptom-specific. The most common therapeutic approaches for IBS include education and reassurance, lifestyles (especially nutrition-based interventions), peripherally acting medications (which typically target motility), centrally acting medications (which target visceral hypersensitivity and pain) and psychological interventions (which aim to reduce the effects of stress or symptom-specific anxiety). A beneficial dietary approach might include the following measures: a diet low in fermentable oligo-,di- and monosaccharides and polyols (FODMAPs), limitation or exclusion of gas-producing foods and/or lactose and gluten and fiber supplementation in selected cases. New therapeutic agents, namely nutraceutics, are also an interesting option in the management of IBS patients. This paper will focus on available dietary interventions for IBS and will review the evidence for nutrition-based therapies.

Effects of cholestyramine on gallbladder and gastric emptying in obese and lean subjects

Gallbladder stasis is frequent in obese subjects and may contribute to their increased risk for gallstone formation. The bile salt sequestrant cholestyramine acutely enhances postprandial gallbladder emptying in lean subjects, through disinhibition of a negative feedback between intraluminal bile salts and CCK release. In this study the effect of cholestyramine on both gallbladder and gastric antrum dynamics were studied by real-time ultrasonography in 12 obese and 15 lean subjects. For the acute study, on different days, subjects ingested a liquid meal (two egg yolks plus water 200 mL, 50 kJ) or a meal with 4 g cholestyramine. Gallbladder emptying was impaired in obese patients who had significantly larger fasting gallbladder volume (39.4 +/- 6.9 vs. 21.6 +/- 1.7 mL, P < 0.02), larger residual volume (12.3 +/- 1.8 vs. 4.0 +/- 0.5 ml, P < 0.0006) and slower emptying time (T/2: 33 +/- 2 vs. 21 +/- 2 min, P < 0.05) than lean subjects. Integrated antral emptying was also less in obese than lean subjects (5521 +/- 578 vs. 7908 +/- 491 %120 min-1, P < 0.02). Cholestyramine enhanced postprandial gallbladder emptying in both obese and lean subjects. Gastric emptying was delayed with cholestyramine in lean but not obese subjects. For the chronic study, after 1 month therapy with cholestyramine (4 g every 2 days), the motility tests were repeated in nine obese subjects. Gallbladder and gastric responses to a test meal, with or without cholestyramine, were preserved. We conclude that both gallbladder and antral emptying of a liquid test meal are impaired in obese subjects. Gallbladder emptying improves after acute administration of a low dose cholestyramine with test meal. This effect is sustained after 1 month treatment with a low dose of cholestyramine and does not interfere with gastric emptying of obese patients. Cholestyramine may improve gallbladder hypomotility in obese people.

Water channel proteins in bile formation and flow in health and disease: when immiscible becomes miscible

An essential function of the liver is the formation and secretion of bile, a complex aqueous solution of organic and inorganic compounds essential as route for the elimination of body cholesterol as unesterified cholesterol or as bile acids. In bile, a considerable amount of otherwise insoluble cholesterol is solubilized by carriers including two other classes of lipids, namely phospholipid and bile acids. Formation of bile and generation of bile flow are driven by the active secretion of bile acids, lipids and electrolytes into the canalicular and bile duct lumens followed by the parallel movement of water. Thus, water has to cross rapidly into and out of the cell interior driven by osmotic forces. Bile as a fluid, results from complicated interplay of hepatocyte and cholangiocyte uptake and secretion, concentration, by involving a number of transporters of lipids, anions, cations, and water. The discovery of the aquaporin water channels, has clarified the mechanisms by which water, the major component of bile (more than 95%), moves across the hepatobiliary epithelia. This review is focusing on novel acquisitions in liver membrane lipidic and water transport and functional participation of aquaporin water channels in multiple aspects of hepatobiliary fluid balance. Involvement of aquaporins in a series of clinically relevant hepatobiliary disorders are also discussed.

Bile Acids and GPBAR-1: Dynamic Interaction Involving Genes, Environment and Gut Microbiome

Bile acids (BA) are amphiphilic molecules synthesized in the liver from cholesterol. BA undergo continuous enterohepatic recycling through intestinal biotransformation by gut microbiome and reabsorption into the portal tract for uptake by hepatocytes. BA are detergent molecules aiding the digestion and absorption of dietary fat and fat-soluble vitamins, but also act as important signaling molecules via the nuclear receptor, farnesoid X receptor (FXR), and the membrane-associated G protein-coupled bile acid receptor 1 (GPBAR-1) in the distal intestine, liver and extra hepatic tissues. The hydrophilic-hydrophobic balance of the BA pool is finely regulated to prevent BA overload and liver injury. By contrast, hydrophilic BA can be hepatoprotective. The ultimate effects of BA-mediated activation of GPBAR-1 is poorly understood, but this receptor may play a role in protecting the remnant liver and in maintaining biliary homeostasis. In addition, GPBAR-1 acts on pathways involved in inflammation, biliary epithelial barrier permeability, BA pool hydrophobicity, and sinusoidal blood flow. Recent evidence suggests that environmental factors influence GPBAR-1 gene expression. Thus, targeting GPBAR-1 might improve liver protection, facilitating beneficial metabolic effects through primary prevention measures. Here, we discuss the complex pathways linked to BA effects, signaling properties of the GPBAR-1, mechanisms of liver damage, gene-environment interactions, and therapeutic aspects.

Parallel intestinal and liver injury during early cholestasis in the rat: modulation by bile salts and antioxidants

Whereas long-term cholestasis results in intestinal alterations and increased permeability to hepatotoxins, the effect of short-term cholestasis is less known and was investigated in bile duct ligated (BDL) rats. In the intestinal mucosa, at Day 7 BDL, total glutathione and protein sulfhydryl contents had decreased, oxidized glutathione levels increased (P<0.05 vs baseline), and a reduced epithelium thickness with dissolving crypt phenomena was observed in 40% of rats. At Day 10, total protein content, glutathione-related enzyme activities, and the transmural electrophysiological activity had decreased (-50%); by contrast, oxidized proteins doubled (P<0.05), and histological changes were extended to 70% of rats. In vitro exposure to taurodeoxycholate at micellar concentrations determined dysepithelization in normal gut but dissolving crypt phenomena and necrosis in cholestatic bowels. In the liver, ongoing cholestasis was associated with early oxidative changes especially in mitochondria, where protein sulfhydryls were decreased and negatively correlated with glutathione-protein mixed disulfides (r=-0.807, P<0.001). Daily oral administration of tauroursodeoxycholate, a hydrophilic bile salt, and glutathione to BDL rats improved intestinal histology, function, and redox state. In conclusion, short-term cholestasis results in distinctive functional, oxidative, and morphological changes of intestinal mucosa, determined increased vulnerability to toxic injury, and parallel hepatic oxidative damage.

Colchicine, Biologic Agents and More for the Treatment of Familial Mediterranean Fever. The Old, the New, and the Rare

Familial Mediterranean Fever (FMF) is a rare autosomal recessive autoinflammatory disorder involving the innate immunity and affecting almost exclusively populations with Mediterranean origin. Clinical features include recurrent episodes of fever, leukocitosis, serositis (peritonitis or pleuritis, arthritis), myalgia or erysipelas-like skin lesions, lasting 12-72 hrs. The MEFV gene mutations on chromosome 16p13.3 encodes the abnormal pyrin (marenostrin), a protein expressed in granulocytes, monocytes, serosal and synovial fibroblasts and involved in the activation of caspase-1 and the processing and release of active pro-inflammatory IL-1β. Since the first report in 1972, maintenance therapy with colchicine, a tricyclic neutral alkaloid, remains the mainstay of treatment in symptomatic FMF patients since it reduces the disease activity and prevents the development of secondary amyloidosis and renal damage. Adjunctive symptomatic therapy to colchicine includes nonsteroideal antinflammatory drugs and corticosteroids. In a small group of colchicine-intolerant or colchicine-resistant FMF patients, alternative treatments must be considered. Evolving experiences have focussed on the potential effectiveness of biologic agents working as TNF-α inhibitors (etanercept, infliximab), IL-1 trap (Rilonacept), IL-1 inhibitors (Anakinra, Canakinumab) and IL-6 receptor antibody (Tocilizumab). Interferon-α and thalidomide have also been employed in FMF patients. Still, clinical trials are mainly uncontrolled and restricted to few cases, thus requiring definitive conclusions. Old, and new treatments are discussed in the rare FMF disease, with the concept that any ideal treatment has to stand the test of time.

Familial mediterranean fever: a fascinating model of inherited autoinflammatory disorder

BACKGROUND

Familial Mediterranean fever (FMF) is a rare inherited autosomal recessive autoinflammatory disorder characterized by recurrent and self-limited episodes of fever and painful serositis, lasting 1-3 days. FMF occurs almost exclusively among ethnic groups of the Mediterranean basin, although cases have also been found in Japan and Korean populations. Diagnosis is based on clinical features, response to colchicine and genetic analysis. Novel drugs are emerging, allowing better management of colchicine-resistant/colchicine-intolerant patients. This review aims to attract the attention of the readers on differential diagnosis and management of patients with FMF.

METHODS

The current state-of-the-art on FMF is outlined, with respect to epidemiological, genetic, pathophysiological and therapeutic characteristics, based on critical analysis of solid scientific literature.

RESULTS

FMF is more frequent than it was thought before. The phenotypic expression of M694V is more severe than that of V726A. Patients with M694V/M694V homozygosity are exposed to a higher risk of developing renal amyloidosis, arthritis, dermatologic and oral lesions, higher fever and more frequent painful attacks. Life-long therapy with colchicine (1·0-2·4 mg/day) is effective and safe to prevent recurrent attacks and renal amyloidosis and to reverse proteinuria. In nonresponder patients, alternative novel approaches include interleukin-1 receptor antagonist anakinra and the interleukin-1 decoy receptor rilonacept.

CONCLUSIONS

The prognosis of FMF is normal if AA amyloidosis is prevented. Colchicine remains the first-line therapy to treat pain and prevent amyloidosis. A follow-up should include clinical evaluation, therapeutic adjustments, measurement of serum amyloid A and proteinuria.