Yves Gallois

A novel panel of blood markers to assess the degree of liver fibrosis

The objective was to develop new blood tests to characterize different fibrosis parameters in viral and alcoholic chronic liver diseases. Measurements included 51 blood markers and Fibrotest, Fibrospect, ELFG, APRI, and Forns scores. The clinically significant fibrosis was evaluated via Metavir staging (F2‐F4), and image analysis was used to determine the area of fibrosis. In an exploratory step in 383 patients with viral hepatitis, the area under the receiving operator characteristic (AUROC) curve for stages F2‐F4 in a test termed the “Fibrometer” test combining platelets, prothrombin index, aspartate aminotransferase, α2‐macroglobulin (A2M), hyaluronate, urea, and age was 0.883 compared with 0.808 for the Fibrotest (P = .01), 0.820 for the Forns test (P = .005), and 0.794 for the APRI test (P < 10−4). The Fibrometer AUROC curve was 0.892 in the validating step in 120 patients. The AUROC curve for stages F2‐F4 in a test combining prothrombin index, A2M, hyaluronate, and age was 0.962 in 95 patients with alcoholic liver diseases. The area of fibrosis was estimated in viral hepatitis by testing for hyaluronate, γ‐glutamyltransferase, bilirubin, platelets, and apolipoprotein A1 (aR2 = 0.645), and in alcoholic liver diseases by testing for hyaluronate, prothrombin index, A2M, and platelets (aR2 = 0.836). In conclusion, the pathological staging and area of liver fibrosis can be estimated using different combinations of blood markers in viral and alcoholic liver diseases. Whereas the Fibrometer has a high diagnostic accuracy for clinically significant fibrosis, blood tests for the area of liver fibrosis provide a quantitative estimation of the amount of fibrosis, which is especially useful in cirrhosis. (HEPATOLOGY 2005.)

Relationships Between Angiotensin I Converting Enzyme Gene Polymorphism, Plasma Levels, and Diabetic Retinal and Renal Complications

Insulin-dependent diabetes mellitus (IDDM), cardiovascular morbidity, and vital prognosis are linked to diabetic nephropathy, which is probably determined by renal hemodynamic abnormalities and by a genetic predisposition. Angiotensin I converting enzyme (ACE) regulates systemic and renal circulations through angiotensin II formation and kinins metabolism. Plasma and cellular ACE levels are genetically determined; an insertion/deletion polymorphism of the ACE gene is strongly associated with ACE levels, subjects homozygote for insertion (genotype II) having the lowest plasma values. We studied the relationship between the ACE gene polymorphism or plasma levels and microcirculatory disorders of IDDM through two independent studies: one involved 57 subjects with or without diabetic retinopathy, and the other compared 62 IDDM subjects with diabetic nephropathy to 62 diabetic control subjects with the same characteristics (including retinopathy severity) but with normal kidney function. The ACE genotype distribution was not different in diabetic subjects with or without retinopathy and in a healthy population. Conversely, an imbalance of ACE genotype distribution, with a low proportion of II subjects, was observed in IDDM subjects with diabetic nephropathy compared with their control subjects (P = 0.006). Plasma ACE levels were mildly elevated in all diabetic groups, independently of retinopathy, but they were higher in subjects with nephropathy than in those without nephropathy (P = 0.0022). The II genotype of ACE gene is a marker for reduced risk for diabetic nephropathy.

Determination of reliability criteria for liver stiffness evaluation by transient elastography

Liver stiffness evaluation (LSE) is usually considered as reliable when it fulfills all the following criteria: ≥10 valid measurements, ≥60% success rate, and interquartile range / median ratio (IQR/M) ≤0.30. However, such reliable LSE have never been shown to be more accurate than unreliable LSE. Thus, we aimed to evaluate the relevance of the usual definition for LSE reliability, and to improve reliability by using diagnostic accuracy as a primary outcome in a large population. 1,165 patients with chronic liver disease from 19 French centers were included. All patients had liver biopsy and LSE. 75.7% of LSE were reliable according to the usual definition. However, these reliable LSE were not significantly more accurate than unreliable LSE with, respectively: 85.8% versus 81.5% well‐classified patients for the diagnosis of cirrhosis (P = 0.082). In multivariate analyses with different diagnostic targets, LSE median and IQR/M were independent predictors of fibrosis staging, with no significant influence of ≥10 valid measurements or LSE success rate. These two reliability criteria determined three LSE groups: “very reliable” (IQR/M ≤0.10), “reliable” (0.10< IQR/M ≤0.30, or IQR/M >0.30 with LSE median <7.1 kPa), and “poorly reliable” (IQR/M >0.30 with LSE median ≥7.1 kPa). The rates of well‐classified patients for the diagnosis of cirrhosis were, respectively: 90.4%, 85.8%, and 69.5% (P < 10−3). According to these new reliability criteria, 9.1% of LSE were poorly reliable (versus 24.3% unreliable LSE with the usual definition, P < 10−3), 74.3% were reliable, and 16.6% were very reliable. Conclusion: The usual definition for LSE reliability is not relevant. LSE reliability depends on IQR/M according to liver stiffness median level, defining thus three reliability categories: very reliable, reliable, and poorly reliable LSE. (HEPATOLOGY 2013)

Histopathological evaluation of liver fibrosis: quantitative image analysis vs semi-quantitative scores: Comparison with serum markers

BACKGROUND/AIMS Liver fibrosis is mainly evaluated by qualitative histological examination. Although histological semi-quantitative scores and quantitative determination with image analysis are now possible, these methods have not been fully validated and compared. Therefore, we evaluated these two methods prospectively in 243 patients with chronic liver disease. METHODS The semi-quantitative fibrosis score was evaluated by two independent pathologists, using the Knodell fibrosis score and a 6-grade score derived from the Metavir score; the area of fibrosis was measured by image analysis. The serum levels of hyaluronate, N-terminal peptide of procollagen III, laminin, transforming growth factor-beta1, alpha2-macroglobulin, apolipoprotein A1, PGA score and prothrombin index were measured. RESULTS There was a good correlation between the semi-quantitative fibrosis score and the area of fibrosis (r=0.84, p<10(-4)). Using multiple regression analysis, the semi-quantitative score was predicted by the 8 serum markers with R2=0.69 (R2=0.59 for hyaluronate at the 1st step) while the area of fibrosis was predicted with R2=0.79 (R2=0.76 for hyaluronate at the 1st step), and the Knodell fibrosis score was predicted with R2=0.65 (R2=0.31 for hyaluronate at the 1st step). CONCLUSIONS The area of fibrosis, as determined by image analysis, and the semi-quantitative score are well correlated. However, for serum markers the correlation is higher with the area of fibrosis than with the semi-quantitative score. Other characteristics such as reproducibility, rapidity, simplicity, adaptability, and exhaustiveness also favor image analysis.

Gamma irradiation of human bone allografts alters medullary lipids and releases toxic compounds for osteoblast-like cells.

The uncertainties about the transmission of prion proteins from xenogenic grafts prepared from bovine bone has led to the reconsideration of allogenic bone as a grafting material. Allografting is a complementary technique to autografting nowadays when large bone volumes are necessary. Several preparation techniques have been proposed. Fresh-frozen, freeze-dried and gamma irradiation are the most common. However, a large amount of lipids is present in the medullary spaces (near 70% in weight for a human femoral head). They are known to strongly influence the biocompatibility of the bone graft. The exact changes of lipids upon the sterilization and storage processes are poorly known. The aims of the present study were to appreciate the effects of gamma irradiation on medullary lipids and to identify the cytotoxicity of gamma-irradiated bank bone with/without lipid on cultures of osteoblast-like cells. Bone cores from 8 femoral heads retrieved during prosthesis surgery for arthritis were prepared with a drilling trephine. Cores were either sterilized by gamma radiations (25000 gray) or kept frozen until lipid extraction and lipofuschine-like dosage by Folchs method and fluorometric study. Peroxidated lipids appeared 2 to 3-fold higher in the gamma-irradiated cores than in frozen ones. Slices were prepared from bone cores and were transferred on confluent osteoblast-like cell layers (Saos-2). The raw slices (containing lipids) did not induce cell death. On the other hand, cell death was dramatically increased around the gamma-irradiated slices. Defatted slices which had been sterilized by gamma radiations or UV did not induce cell death. Defatting procedures should be added when preparing bone allografts in human bone banks.

Non-invasive diagnosis of esophageal varices in chronic liver diseases

BACKGROUND/AIMS The primary prevention of bleeding from esophageal varices is a major therapeutic issue requiring early screening of esophageal varices. Our aim was to study the diagnostic accuracy of non-endoscopic means for the diagnosis of esophageal varices. METHODS Sixty-three clinical, biochemical, endoscopic and Doppler ultrasound variables were prospectively recorded in 207 consecutive patients with chronic liver disease. Diagnostic accuracy was evaluated by discriminant analysis, first globally using all variables with diagnostic accuracy > or = 65% in univariate analysis, then by stepwise regression. RESULTS A) whole group (n=207), 1) diagnosis of esophageal varices: diagnostic accuracy was globally 81%, and 81% with 1 variable: irregular liver surface at ultrasound, 2) Diagnosis of large esophageal varices (grades 2+3): diagnostic accuracy was globally 80%, and 79% with 2 variables: prothrombin index, gamma-globulins. B) patients with cirrhosis (n=116), 1) diagnosis of esophageal varices: diagnostic accuracy was globally 71%, and 72% with 2 variables: platelet count, prothrombin index, 2) diagnosis of large esophageal varices (grades 2+3): diagnostic accuracy was globally 71%, and 72% with 3 variables: platelet count, prothrombin index, spider naevi. The ROC curve showed that the best threshold for the diagnostic accuracy of platelet count was 160 G/l providing a sensitivity of 80% and a specificity of 58%. Platelet count > or = 260 G/l has a negative predictive value > or = 91%. CONCLUSIONS Using a few non-endoscopic criteria, esophageal varices can be correctly diagnosed in 81% of patients with chronic liver disease and in 71% of patients with cirrhosis. These results show that the non-invasive screening of patients who are candidates for the primary prevention of variceal bleeding is possible, but should be improved before being used in a clinical setting.

Genetically increased angiotensin I-converting enzyme level and renal complications in the diabetic mouse

Diabetic nephropathy is a major risk factor for end-stage renal disease and cardiovascular diseases and has a marked genetic component. A common variant (D allele) of the angiotensin Iconverting enzyme (ACE) gene, determining higher enzyme levels, has been associated with diabetic nephropathy. To address causality underlying this association, we induced diabetes in mice having one, two, or three copies of the gene, normal blood pressure, and an enzyme level range (65–162% of wild type) comparable to that seen in humans. Twelve weeks later, the three-copy diabetic mice had increased blood pressures and overt proteinuria. Proteinuria was correlated to plasma ACE level in the three-copy diabetic mice. Thus, a modest genetic increase in ACE levels is sufficient to cause nephropathy in diabetic mice.

Acoustic radiation force impulse: a new ultrasonographic technology for the widespread noninvasive diagnosis of liver fibrosis.

Background/aims As a module of a standard ultrasound imaging device, acoustic radiation force impulse (ARFI) is a new technology for liver stiffness evaluation (LSE). We aimed to evaluate accuracy, feasibility, reproducibility, and training effect of ARFI for liver fibrosis evaluation. Methods One hundred and one patients with chronic liver disease had LSE by Fibroscan and ARFI. LSE by ARFI was performed in the two liver lobes by two operators: an expert and a novice. Correlation and agreement were evaluated by the Pearson (Rp) and intraclass (Ric) correlation coefficients. The independent reference for liver fibrosis was fibrosis blood tests. Results ARFI results, ranging from 0.7 to 4.6 m/s, were well correlated with Fibroscan results (Rp=0.76). Fibroscan had a significantly higher area under the receiver operating characteristic curve (AUROC) than ARFI for the perprotocol diagnosis of significant fibrosis: 0.890±0.034 versus 0.795±0.047 (P=0.04). However, LSE failure occurred in zero patients using ARFI versus six patients using Fibroscan (P=0.03). Thus, on an intention-to-diagnose basis, Fibroscan and ARFI AUROCs for the diagnosis of significant fibrosis were not different: 0.791±0.049 versus 0.793±0.046 (P=0.98). Interobserver agreement was very good (Ric=0.84) and excellent for ARFI interquartile range (IQR)≤0.30 (Ric=0.91). Indeed, agreement was independently predicted only by ARFI IQR, but not by LSE result as earlier observed for Fibroscan. ARFI AUROC was 0.876±0.057 in patients with ARFI IQR ratio≤0.30, and Fibroscan AUROC was 0.912±0.034 in patients with Fibroscan IQR ratio less than 0.21 (P=0.59). Intersite ARFI agreement between the two liver lobes was fair (Ric=0.60). There was no training effect for LSE by ARFI. Conclusion ARFI is highly feasible and reproducible, and provides diagnostic accuracy similar to Fibroscan. This new device seems noteworthy for the widespread noninvasive diagnosis of liver fibrosis.

The combination of a blood test and Fibroscan improves the non‐invasive diagnosis of liver fibrosis

Background and aims: Blood tests and liver stiffness evaluation (LSE) by ultrasonographic elastometry are accurate tools for diagnosing liver fibrosis. We evaluated whether their synchronous combination in new scores could improve the diagnostic accuracy and reduce liver biopsy requirement in algorithm.

Hemodynamic and antifibrotic effects of losartan in rats with liver fibrosis and/or portal hypertension

BACKGROUND/AIMS To assess the effects of the early and chronic administration of losartan--a specific angiotensin II receptor antagonist--in the prevention of hepatic fibrosis and portal hypertension. METHODS/RESULTS (1) In CCl(4) rats, losartan at 5 and 10 mg/kg per day significantly decreased portal pressure (-11, -18%, respectively), splenorenal shunt blood flow (-60, -80%) and liver fibrosis (liver hydroxyproline and area of fibrosis) without significant changes in mortality and mean arterial pressure (MAP). (2) In bile duct ligated (BDL) rats, losartan at 5 mg/kg per day significantly decreased portal pressure (-14%), splenorenal shunt blood flow (-70%) and liver fibrosis. Losartan at 10 mg/kg per day significantly worsened liver and renal functions, mortality and liver fibrosis, without significant changes in portal pressure and splenorenal shunt blood flow. Losartan at 5 and 10 mg/kg per day significantly decreased MAP (-24, -30%). (3) In portal vein ligated (PVL) rats, losartan significantly decreased MAP (-12%) but did not change portal pressure or splenorenal shunt blood flow. CONCLUSIONS In BDL and CCl(4) rats, losartan has beneficial effects on splanchnic hemodynamics and liver fibrosis. Losartan might decrease hepatic resistances in fibrotic liver. Losartan decreased MAP except in CCl(4) rats. Higher dosage of losartan had deleterious effects in BDL rats.