Pierre-Michel Huet

The inflammatory C-reactive protein is increased in both liver and adipose tissue in severely obese patients independently from metabolic syndrome, Type 2 diabetes, and NASH.

OBJECTIVE:C-Reactive Protein (CRP), a nonspecific marker of inflammation that is moderately elevated in obesity, metabolic syndrome (MS), and type 2 diabetes, has been proposed as a surrogate marker of nonalcoholic steatohepatitis (NASH). Its clinical usefulness in the diagnosis of NASH was evaluated in severely obese patients without or with MS, diabetes, and NASH and the potential roles of the liver and of the adipose tissue in CRP production were characterized.METHODS:Severely obese patients without NASH (without MS [N = 13], with MS [N = 11], or with MS and diabetes [N = 7]) and with NASH (without [N = 8] or with [N = 7] MS) were studied. For each patient, liver and adipose tissue biopsies were collected during a bariatric surgery and were used to determine the CRP gene expression by real-time PCR. The role of interleukin-6 (IL6) and lipopolysaccharide in CRP expression was also evaluated in subcutaneous adipose tissue obtained during cosmetic abdominoplasty.RESULTS:Plasma CRP levels were elevated in severely obese patients independently from the presence or absence of MS, diabetes, or NASH. CRP gene expression was not only increased in livers but also in adipose tissues of obese patients compared with controls subjects. In human adipose tissue, CRP mRNA levels were positively correlated with those of IL-6 and the CRP expression was enhanced in vitro by IL-6 and lipopolysaccharide.CONCLUSION:Plasma CRP levels are not predictive of the diagnosis of NASH in severely obese patients. The liver but also the adipose tissue can produce CRP, a process which could be dependent on IL6. Therefore, both tissues might contribute to the elevated plasma CRP levels found in obesity. In addition, the large amount of body fat may well produce an important part of the circulating CRP, further limiting its clinical usefulness in the evaluation of NASH in severely obese patients.

Elevated Expression of Osteopontin May Be Related to Adipose Tissue Macrophage Accumulation and Liver Steatosis in Morbid Obesity

OBJECTIVE—Osteopontin (OPN) plays an important role in the development of insulin resistance and liver complications in dietary murine models. We aimed to determine the expression pattern of OPN and its receptor CD44 in obese patients and mice according to insulin resistance and liver steatosis. RESEARCH DESIGN AND METHODS—OPN and CD44 expressions were studied in 52 morbidly obese patients and in mice. Cellular studies were performed in HepG2 cells. RESULTS—Hepatic OPN and CD44 expressions were strongly correlated with liver steatosis and insulin resistance in obese patients and mice. This increased OPN expression could be due to the accumulation of triglycerides, since fat loading in HepG2 promotes OPN expression. In contrast, OPN expression in adipose tissue (AT) was enhanced independently of insulin resistance and hepatic steatosis in obese patients. The elevated OPN expression in AT was paralleled with the AT macrophage infiltration, and both phenomena were reversed after weight loss. The circulating OPN level was slightly elevated in obese patients and was not related to liver steatosis. Further, AT did not appear to secrete OPN. In contrast, bariatric surgery–induced weight loss induced a strong increase in circulating OPN. CONCLUSIONS—The modestly elevated circulating OPN levels in morbidly obese patients were not related to liver steatosis and did not appear to result from adipose tissue secretion. In subcutaneous AT, expression of OPN was directly related to macrophage accumulation independently from liver complications. In contrast, hepatic OPN and CD44 expressions were related to insulin resistance and steatosis, suggesting their local implication in the progression of liver injury.

A new composite model including metabolic syndrome, alanine aminotransferase and cytokeratin-18 for the diagnosis of non-alcoholic steatohepatitis in morbidly obese patients

Aliment Pharmacol Ther 2010; 32: 1315–1322

Bariatric Surgery Can Correct Iron Depletion in Morbidly Obese Women: A Link with Chronic Inflammation

BackgroundObesity is associated with a chronic and low-grade inflammation which may cause hypoferremia as seen in patients with chronic inflammatory diseases. The aim of the present study was to investigate the relationship between iron status and markers of inflammation in morbidly obese women and the effect of bariatric surgery.MethodsOur cohort of patients consisted of 178 morbidly obese females selected for bariatric surgery. Clinical and biochemical data were recorded before surgery, and histopathological studies were carried out on preoperative liver biopsy samples. Fifty-five patients have been followed up after bariatric surgery.ResultsA high prevalence of iron depletion was present in this cohort, with 53% having a transferrin saturation ratio below 0.20. Iron depletion was significantly correlated with raised levels of indices of inflammation, C-reactive protein (CRP), orosomucoid and haptoglobin), and with the white blood cell count. In multivariate analysis, orosomucoid and CRP were independently associated with iron depletion. Moreover, 6xa0months after bariatric surgery, inflammation level decreased, which was inversely correlated with the increase in transferrin saturation.ConclusionsIron depletion is common in morbidly obese women. Low-grade chronic inflammation associated with obesity could be a modulator of iron uptake and utilization. Bariatric surgery may reduce chronic inflammation and improve iron status.

Matrix metalloproteinase inhibition protects rat livers from prolonged cold ischemia–warm reperfusion injury

Matrix metalloproteinases (MMPs) have been implicated in the hepatic injury induced after cold ischemia–warm reperfusion (CI‐WR), by altering the extracellular matrix (ECM), but their precise role remains unknown. The hepatic MMP expression was evaluated after 2 conditions of CI (4°C for 24 and 42 hours: viable and nonviable livers) followed by different periods of WR, using isolated perfused rat livers. CI‐WR induced moderate changes in hepatic MMP transcript levels not influenced by CI duration, whereas gelatinase activities accumulated in liver effluents. Therefore, the protective effect of a new phosphinic MMP inhibitor, RXP409, was tested after prolonged CI. RXP409 (10 μM) was added to the University of Wisconsin solution, and livers were preserved for 42 hours (4°C), then reperfused for 1 hour in Krebs solution (37°C), containing 20% erythrocytes. Liver viability parameters were recorded, and the extent of cell necrosis was evaluated on liver biopsies, using trypan blue nuclear uptake. Treatment with RXP409 significantly improved liver function (transaminase release and bile secretion) and liver injury. In particular, the MMP inhibitor significantly modified the extent of cell death from large clusters of necrotic hepatocytes as found in control livers (2%–60% of liver biopsies; mean, 26% ± 9%) to isolated necrotic hepatocytes as found in treated livers (0.2%–12%; mean, 3% ± 2%) (P < 0.05). Conclusion: These data demonstrate that MMPs, by altering the ECM, play a major role in liver CI‐WR injury leading to extensive hepatocyte necrosis and that their inhibition might prove to be a new strategy in improving preservation solutions. (HEPATOLOGY 2007.)

Predictive factors of bleeding related to post-banding ulcer following endoscopic variceal ligation in cirrhotic patients: a case-control study

Aliment Pharmacol Ther 2010; 32: 225–232

The hepatic venous pressure gradient: “Remixed and revisited”

HVPG is more than 50 years old!2 But what has it taught us regarding the pathophysiology of portal hypertension? A lot, yet it is still not part of the routine investigation of this deadly complication of chronic liver disease. It has never been incorporated in various prognostic indices (Child-Turcotte, Child-Pugh, or model for end-stage liver disease [MELD] scores) and is still not a direct factor in decisions to perform liver transplantation. We know that the HVPG is an acceptable indirect measurement of portal hypertension, because wedged hepatic venous pressure is very close to portal venous pressure (PVP) in most chronic liver diseases, particularly in alcoholic and viral (B and C) cirrhosis.3–6 It is also accepted that changes in portal venous pressure induced by drugs are similarly reflected in wedged hepatic venous pressure, and therefore the HVPG is an adequate measure of drug effects on portal pressure.6 A first important step in demonstrating its usefulness was the threshold value of 12 mmHg above which serious complications of portal hypertension can arise, particularly bleeding gastroesophageal varices.7–9 In the early 1980s, the first demonstration that portal hypertension could be modified by a drug was the decrease in the HVPG after acute or chronic propranolol administration.8,10,11 Subsequently, the ability to prevent bleeding from gastroesophageal varices was associated with an effect on portal pressure.12 HVPG measurement also allowed the identification of responders and nonresponders to -blockers, which explains why protection from gastroesophageal variceal bleeding is not seen in all treated patients.13,14 Now it is generally accepted that decreasing the HVPG below a threshold value of 12 mmHg by any drug or combination of drugs almost completely reduces the risk of first or recurrent bleeding from varices.15,16 Unfortunately, with currently available drugs, this threshold is not frequently attained, except in patients with mild to moderately elevated HVPG and possibly less at risk. In certain patients, a small reduction of the HVPG is associated with a real decline in the risk of first or recurrent bleeding, and it has been proposed that a 20% HVPG decrease should be considered as evidence of a significant response to therapy.16,17 HVPG measurement is a safe technique. No reports of serious complications have been published in the medical literature, and our unit’s experience has been positive after more than 4,000 such procedures. In addition, hepatic vein catheterization offers the possibility of performing liver biopsies in patients with poor coagulation, contraindications for transthoracic liver biopsies, or both. Finally, there is no other less invasive way to estimate the severity of portal hypertension reliably, particularly its changes under medical therapy. No other “splanchnic sphygmomanometer” allows repeated pressure measurements as is the case with arterial sphygmomanometers in the control of high arterial blood pressure.18 So, why is there such resistance to adopt HVPG measurement in clinical practice? The “Perspective in Clinical Hepatology,” written by three expert groups in the field and reported in the present issue of HEPATOLOGY,18–20 may explain why such a procedure still is performed mainly in specialized centers, particularly those involved in clinical trials searching for the best way to prevent first or recurrent bleeding from gastroesophageal varices in patients with chronic liver diseases. Although HVPG measurement is safe and relatively simple, it represents the difference between two pressure readings, doubling the sources of error. In this context, the technical note provided by Groszman and Wongcharatrawee20 is well taken: Any study evaluating the diagnostic or prognostic value of the HVPG must rely on pressure measurements with several technical requirements. Quality control is needed for every hemodynamic evaluation, and it is likely that the criteria for reliable assessments are not always fulfilled in many liver units. Boyer19 suggested that “performing TIPS procedures proAbbreviations: HVPG, hepatic venous pressure gradient; PVP, portal venous pressure. From the 1Fédération d’Hépato-Gastroentérologie, Centre Hospitalier Universitaire de Nice-Hôpital l’Archet 2, Faculté de Médecine, Nice, France; and 2Centre de Recherche, Centre Hospitalier de l’Université de Montréal Hôpital Saint-Luc, and Département de Médecine, Université de Montréal, Montréal, Québec, Canada. Received December 12, 2003; accepted December 12, 2003. Address reprint requests to: Pierre-Michel Huet, M.D., Ph.D., Fédération d’Hépato-Gastroentérologie, Centre Hospitalier Universitaire de Nice-Hôpital l’Archet 2, 151 Route de Saint-Antoine de Ginestière (BP 3079), 06202 Nice Cedex 3, France. E-mail: pierre-michel.huet@wanadoo.fr; fax: 04-92-03-65-77. Copyright

Warm ischemia‐reperfusion injury is decreased by tacrolimus in steatotic rat liver

Ischemia‐reperfusion (I‐R) injury is poorly tolerated by fatty livers, most probably secondary to reduced cellular adenosine triphosphate (ATP) levels. We investigated the effectiveness of tacrolimus pretreatment on fatty liver I‐R injury in obese Zucker rats. Tacrolimus (0.3 mg/kg, intravenously) was injected 24 hours before a 75‐minute ischemic period and rats were sacrificed 6 hours later. Tacrolimus modified the response to I‐R observed in obese Zucker rats, when compared to nontreated obese rats: a significant reduction in hepatocyte necrosis was associated with a significant increase in hepatocyte apoptosis. In addition, cell necrosis and apoptosis were significantly and inversely correlated in lean nontreated and treated obese Zucker rats following I‐R. Tacrolimus also significantly increased the hepatic ATP levels, reduced in nontreated obese rats, toward values found in lean Zucker rat livers. This protective effect of tacrolimus was further confirmed in vivo by a significantly improved survival following pretreatment with tacrolimus, 24 hours prior to ischemia. In conclusion, in obese Zucker rat livers, tacrolimus pretreatment reversed the I‐R injury toward the one found in lean Zucker rats. The correlations between ATP levels and the opposite changes in necrosis and apoptotic pathways strongly suggest a cause‐effect relationship between tacrolimus and changes in ATP levels. Liver Transpl 12:217–225, 2006.

Nasobiliary drainage for cholestatic pruritus.

0.53 vs. 7.71 0.79) and displayed the metabolic syndrome (ATP III criteria7) in 6 subjects versus 0 controls. Dietary vitamin C (40 10 vs. 70 10 g/kcal; P .006) and E (total tocopherols: 2 1 vs. 4 1 g/kcal, P .0001) intake and serum adiponectin (5031 570 vs. 10850 710 ng/mL; P .00001), but not the other cytokines, were lower in NASH. Postprandial plasma Tg and FFA responses were higher in NASH group than in controls, as previously reported.4 Postprandial LDL conjugated diene response was higher in patients with NASH (IAUC LDL conjugated dienes : 5.7 1.1 vs. 0.2 0.1 uA 234 nm/uA 200 nm x 100 x hr; P .0005; Fig 1). On multiple regression analysis, IAUC-FFA ( .50; P .011) and vitamin C intake ( 0.42; P .043) independently predicted IAUC-LDL conjugated dienes. Adiponectin ( 0.55; P .011) and IAUC-FFA( 0.51; P .031) predicted hepatic steatosis. On logistic regression analysis, adiponectin (OR 6.8; CI 2.5-12.0; P .003) and IAUC-LDL conjugated dienes (OR 4.4; CI 1.6-18.1; P .021) predicted stage 3 fibrosis, independently of age, BMI, ISI index and metabolic syndrome. An enhanced postprandial LDL lipid peroxidation, along with a failing protective action of adiponectin, may thus be key in hepatic oxidative injury in NASH, by binding scavenger receptors CD36 of stellate cells and triggering fibrogenesis.8-10 Therapeutically, postprandial lipoprotein lipid peroxidation could be a major target for those drugs, such as statins and PPARagonists, directly modulating lipid handling and oxidative stress during this phase of metabolism. Dietary intake of antioxidant vitamins should also be encouraged in NASH. GIOVANNI MUSSO, M.D. MAURIZIO CASSADER, M.D. ROBERTO GAMBINO, M.D. MARILENA DURAZZO, M.D. GIANFRANCO PAGANO, M.D. Department of Internal Medicine University of Turin Turin, Italy

Microcirculation of the aging liver: is getting old like having cirrhosis?

What is known about the liver circulation and microcirculation in elderly individuals? Not much. However, new insights may improve our understanding of age-related changes in hepatic perfusion. In the normal adult liver, sinusoids have a unique structure that allows maximum contact between hepatocytes and the blood perfusing the liver. Unlike capillaries in the heart, lung, or brain, the endothelial cells lining sinusoids are perforated by a multitude of fenestrae 50 to 150 nm in diameter, and have no basal membrane. These fenestrae occupy about 5% to 10% of the endothelial surface (porosity) and are most often arranged in groups for which the name sieve plate was given.1 The diameter of these fenestrae appears to decrease slightly from zone 1 to zone 3, while their total porosity increases from 6% to 9%.1 A large extra vascular space, the space of Disse, lies behind the endothelial lining and is continuous with the intercellular space up to the tight junctions of hepatocytes. Normally, only a few collagen bundles can be seen in the space of Disse using electron microscopy (EM) techniques. However, the entire space is not empty and contains several substances forming the extra cellular matrix (i.e., laminin, fibronectin, collagens, hyaluronan, perlecan), which are well identified using immunohistochemical techniques.2 This matrix acts as a semipermeable gel in which large molecules dissolved in plasma can diffuse according to their molecular weights.3 Red and white blood cells as well as large lipoproteins (such as chylomicrons, 100 to 1000 nm in diameter) are larger than the fenestrae and do not have access to the space of Disse. In addition, owing to their size difference, blood cells must adjust their shape in order to pass through the sinusoids and flow in single cell rows.3 A reciprocal adaptation of the endothelial lining is thought to occur during the passage of blood cells, stirring the space of Disse and further improving the exchange of fluid and particles between the blood and hepatocytes.1 At the same time, the flexibility of the endothelial wall, the result of an absent continuous basal lamina and a loose extra vascular matrix, is necessary to maintain the low sinusoidal pressure gradient (less than 5 mm Hg) observed in normal adult liver. The filtering effect of fenestrated endothelial cells may also exhibit temporal variations since fenestrae have been shown to contract and dilate under certain conditions.4 A few years ago, Fraser et al.5 stressed that perturbation in the porosity of sinusoidal endothelial cells, due to changes in size and/or number of fenestrae or to alterations of the extravascular matrix, may have a profound influence on the metabolism of lipoproteins. In particular, the decreased passage of chylomicron remnants ( 50 nm in diameter) through an altered sinusoidal lining may lead to their reduced clearance by the liver and participate in the pathogenesis of atherosclerosis. This factor could at least partially explain their decreased clearance in elderly subjects.6 The multiple indicator dilution technique proposed by Goresky3 provides the best approach to study the unique structure of the normal sinusoidal bed in vivo and to evaluate changes caused by anatomical alterations. This technique involves the injection into the portal vein or hepatic artery of a mixture of different indicators and their collection from the hepatic venous outflow. The indicators used for these studies are usually labeled red blood cells (RBCs) and plasma-dissolved substances (such as albumin, sucrose, and water), which are not metabolized or removed by the liver. In the liver, RBCs are confined to the vascular space during the passage through sinusoids, whereas plasma-dissolved substances gain access to the extravascular space through the fenestrae in and between the endothelial cells. Albumin (MW 69,000) and sucrose (MW 342) diffuse into extravascular spaces that are inversely related to their molecular weights, and water diffuses into the extravascular and cellular spaces. The distribution (and dilution) of plasma-dissolved substances into spaces larger than those of RBCs produces both a major delay and a decrease in the magnitude of the peak of the outflow of diffusible substances when compared with that of RBCs. In normal adult livers, this distribution is flow limited; indeed, the curve of each diffusible substance can be transformed in such a fashion that it can be superimposed upon the RBC curve. This method yields estimates of the sinusoidal blood volume and of the extravascular distribution volume of diffusible substances, measured Abbreviations: EM, electron microscopy; RBC, red blood cell; MW, molecular weight. Address reprint requests to: Pierre-Michel Huet, M.D., Ph.D., Fédération d’Hépato-Gastroentérologie, Centre universitaire de Nice, Hôpital l’Archet 2, 151 route Saint-Antoine de Ginestière (BP 3079), 06202 Nice Cedex 3, France. Email: pierre-michel.huet@wanadoo.fr; fax: (33) 04-92-03-62-24. Copyright