Durval Rosa Borges

Serum hyaluronic acid as a comprehensive marker to assess severity of liver disease in schistosomiasis.

Schistosomiasis mansoni is a non-cirrhotic fibrogenic disease model. The mild form shows normal liver function with slight or no liver fibrosis whereas in the periportal fibrosis form the manifestations of portal hypertension prevail over hepatocellular failure. We assessed serum hyaluronic acid as a marker of the course of the disease. We studied 24 patients presenting with pure chronic forms of schistosomiasis and seven with cirrhosis. In order to measure serum hyaluronic acid we developed a sandwich fluorescent ELISA-like assay. alpha2-Macroglobulin, prothrombin index, gamma-glutamyltransferase, platelets and ultrasound parameters were also assessed. The 20 micro g/l (ROC plot) hyaluronic acid level differentiated patients with the mild form (with no portal hypertension) from those with the severe form of schistosomiasis with 78% diagnostic efficacy. The 80 micro g/l cut-off value differentiated patients with the severe form of schistosomiasis from the cirrhotic group with similar diagnostic efficacy. alpha2-Macroglobulin provided no distinction between the groups studied. The hyaluronic acid serum concentration correlated positively with the splenic vein diameter (P=0.004) and marginally with alpha2-macroglobulin (P=0.059). Serum hyaluronic acid is a good marker for the initial phase of hepatic fibrosis and it was able to assess severity of liver disease in schistosomiasis.

Thrombocytemia as a predictor of portal hypertension in schistosomiasis.

Sufferers of schistosomiasis mansoni can evolve a clinical form of the disease associated with portal hypertension. To differentiate this form, routine clinical tests and biological indices were evaluated. In all, 54 HBsAg- and HCV-negative patients were studied, 42 with schistosomiasis and 12 normal volunteers. Using clinical criteria, ultrasonography, and endoscopy, the schistosomiasis patients were classified into two groups: mild chronic form (MS, N = 14) and chronic form associated with portal hypertension (PH, N = 28). The laboratory parameters of the MS group did not differ from the controls. The PH group differed from the others in prothrombin index, thrombocytemia, γ-glutamyltransferase, serum α2-macroglobulin, and the calculated indices. ROC plot cutoff levels verified that isolated thrombocytemia was the most efficient marker for discrimination of the PH and MS forms. Thrombocytemia of 130 × 109 platelets/liter discriminated the groups with an 86% accuracy when all patients were analyzed and 96% when only schistosomiasis patients who did not consume alcohol were included.

The recognition site for hepatic clearance of plasma kallikrein is on its heavy chain and is latent on prokallikrein

We partially purified the glycoproteins prokallikrein and kallikrein from rat plasma. The purification of rat plasma kallikrein may result in two forms: an intact form (alpha, M(r) 84-87 kDa) and a partially degraded form (beta, M(r) 46-51 kDa). The alpha-form is composed of a heavy chain (M(r) 50 kDa) and a light chain (M(r) 34-37 kDa) linked by a disulfide bond. The catalytic site is found on the light chain. The beta-form has a partially degraded heavy chain (M(r) 28 kDa). Using a preparation of exsanguinated and perfused rat liver, we verified that rat plasma prokallikrein is not activated by the liver and that neither the proenzyme nor the light chain is removed by the organ. Both forms (alpha and beta) of the active enzyme are similarly removed from the perfusate. We also observed that the clearance of plasma kallikrein is temperature-dependent, and not affected by substances that inhibit binding to galactosyl-, mannosyl-, fucosyl- or phosphomannosyl-specific lectins, but inhibited by beta-galactosides. We suggest that: (a) the binding site to hepatocytes is latent on prokallikrein and is located on its heavy chain, more specifically on the 28-kDa fragment still present in the beta form of the active enzyme and (b) plasma kallikrein is recognized by an S-type lectin.

Differentiating Cirrhosis and Chronic Hepatosplenic Schistosomiasis Using MRI

OBJECTIVE The objective of our study was to identify which imaging features may be used to differentiate between cirrhosis and chronic hepatosplenic schistosomiasis and to assess image interpretation agreement for MRI findings. MATERIALS AND METHODS Retrospective review of 27 patients with alcoholic or virus-induced cirrhosis and 24 patients with chronic hepatosplenic schistosomiasis who underwent MRI (1.5 T) of the abdomen was performed. Images were interpreted independently by two radiologists evaluating the following MRI features: hepatic fissure widening, irregularity of hepatic contours, periportal fibrosis, hepatic parenchyma heterogeneity, and splenic siderotic nodules. Left, right, and caudate hepatic lobe measurements were obtained, and the splenic index was measured. The Fishers exact test, chi-square test, and Students t test were used to compare both groups, and regression analysis was performed. Observer agreement was measured using kappa and intraclass correlation tests. RESULTS Periportal fibrosis, heterogeneity of hepatic parenchyma, and splenic siderotic nodules were more frequent in the group with schistosomiasis (p < 0.05), with periportal fibrosis showing the largest difference in presence and distribution (peripheral greater than central). The transverse diameter of the right hepatic lobe, caudate lobe-right lobe ratio, and splenic index were larger in patients with chronic schistosomiasis (p < 0.001). At multiple regression analysis, splenic siderotic nodules, splenic index, and caudate lobe-right lobe ratio were predictive of schistosomiasis. Observer agreement was substantial or almost perfect for almost all variables analyzed (kappa or r = 0.81-1.00). CONCLUSION The presence of peripheral periportal fibrosis, heterogeneity of hepatic parenchyma, and splenic siderotic nodules, and the splenic index and caudate lobe-right lobe ratio are useful features for differentiating alcoholic or virus-induced cirrhosis from chronic schistosomiasis using MRI.

Participation of a galectin-dependent mechanism in the hepatic clearance of tissue-type plasminogen activator and plasma kallikrein

Tissue-type plasminogen activator (tPA) is a serine protease that plays a central role in the fibrinolytic system, activating plasminogen to plasmin, which degrades the fibrin that is present in blood clots. tPA has proven to be a potent drug in thrombolytic therapy, however, its use is limited due to the rapid clearance from circulation by active hepatic uptake [1]. The uptake mechanism for tPA in the liver involves endothelial and parenchymal cells [2]. A carbohydrate recognition system for tPA in sinusoidal endothelial cells and tPA binding to asialoglycoprotein receptor in parenchymal cells were described [3]. Uptake by sinusoidal endothelial cells involves an interaction between the carbohydrate group in the kringle1 domain and the mannose receptor. A minor involvement of fucose residue has also been suggested in the recognition of tPA by these cells [4,5]. On the other hand, uptake by parenchymal liver cells is mediated mainly by LDL receptor-related protein (LRP) [6,7], a well-known multiligand receptor that also mediates the clearance of a2Macroglobulin(a2M)-proteinases complexes [8]. We have shown that the hepatic clearance rate of complexes such as a2M-kallikrein [9] and a2M-trypsin [10] is decreased compared to the free enzyme. The 39-kDa receptor-associated protein (RAP) is a receptor antagonist that inhibits ligand interactions with the receptors that belong to the low-density lipoprotein receptor gene family. RAP can also function intracellularly as a molecular chaperone for LRP and can regulate its ligand binding activity along the secretory pathway. In addition, RAP also plays an important role in receptor folding [11]. Recently, Camani et al. [12] showed that in some cells the presence of functional LRP is not sufficient for efficient tPA degradation, suggesting that tPA degradation requires a co-receptor. Secretion of tPA is potently stimulated by bradykinin, a nonapeptide released from hydrolysis of high-molecularweight kininogen by kallikrein [13], linking the fibrinolytic and kallikrein–kinin systems. We have already shown that tPA and RPK compete for a common, but not unique, pathway for hepatic clearance [14]. In addition, a plasma kallikrein-dependent plasminogen cascade is required for adipocyte differentiation [15]. Plasma kallikrein circulates in the plasma as its zymogen, prekallikrein. After activation, plasma kallikrein is involved in different biological processes including the pathogenesis of inflammatory reaction, blood flow control, blood pressure control and intrinsic coagulation and fibrinolytic systems [16]. Recently, Akita et al. [17] showed that after partial hepatectomy an excessive amount of TNF-a, the major initiator of hepatic regeneration, may trigger the generation of TGF-h via enhancement of surface plasma kallikrein activity on stellate cells. The proteolytic activity of plasma kallikrein is modulated by plasma inhibitors and its concentration by liver clearance. Rat plasma prekallikrein and the light chain of rat plasma kallikrein (RPK) are not cleared by the isolated and exsanguinated rat liver. The binding site of RPK to hepatic cells is

Kinin-inactivating endopeptidase from rat liver☆

A kinin-inactivating serine-endopeptidase from rat liver was purified to an activity of 912 mU/mg of protein, when measured on bradykinin. The endopeptidase molecular weight, estimated by gel filtration, was 68,000. Its isoelectric point was close to pH 4.9. Vm for the hydrolysis of bradykinin, was 1.25 mumol/min/mg protein; Km was 28 microM. The two hydrolysis products from bradykinin were the pentapeptide Arg1-Phe5 and the tetrapeptide Ser6-Arg9.

Fate of bradykinin on the rat liver when administered by the venous or arterial route

Background and Aim: Bradykinin (BK) infused into the portal vein elicits a hypertensive response via the B2 receptor (B2R) and is efficiently hydrolyzed by the liver. Our purpose was to characterize the mechanism of interaction between BK and the liver.

Thimet oligopeptidase EC 3.4.24.15 is a major liver kininase

Bradykinin (BK) is a potent hepato-portal hypertensive agent although it is efficiently inactivated by the liver. The organ converts angiotensin I to AII, but at a much slower rate than it inactivates BK. We had previously identified EC 3.4.24.15 as an hepatic bradykinin inactivating endopeptidase that hydrolyzes BK at the F5-F6 bond. The aim of this study was to determine the relative importance of BIE, as compared to other kininases, in normal, cirrhotic or inflamed rat livers, as well as in samples of human liver. Using specific substrates and inhibitors we showed that: 1) purified BIE preparation hydrolyzed BK and a BK analogue (BK-Q) with similar efficacy; BK-Q was functionally active since it caused an increase in hepato-portal pressure, as did BK itself. 2) BK degradation in rat serum was performed by ACE since BIE and prolylendopeptidase (PEP) activities were negligible. 3) normal rat liver homogenate contained a large amount of BIE activity which was eliminated by a specific EC 3.4.24.15 inhibitor; ACE and PEP activities were negligible. 4) There was no difference (p>0.05) in BIE activity in the liver homogenates from rats with normal, inflamed or cirrhotic livers. 5) BIE activity was efficiently removed from livers (normal, inflamed or cirrhotic) that were perfused with TritonX-100.6) Human liver had an similar enzymatic pattern although ACE activity was detected. We concluded that in normal, inflamed or cirrhotic rat livers, as well as in the human liver, the bradykinin inactivating endopeptidase (EC 3.4.24.15), and not ACE, is the major hepatic kininase.

Elevação da gama-glutamiltransferase sérica na hepatopatia esquistossomótica não se correlaciona com a carga parasitária e precede alterações ultra-sonográficas

BACKGROUND Liver disorders are the major manifestations of schistosomiasis mansoni. Factors that account for increased concentrations of cholestasis-indicating enzymes in the hepatosplenic form of the disease are unknown. OBJECTIVE To assess the correlation between increased gamma-glutamyltransferase serum levels and both the parasitic load and ultrasound alterations in patients with schistosomiasis. PATIENTS AND METHODS Twenty-five patients with the chronic form of schistosomiasis were assessed for the presence or absence of increased enzymatic levels, for the parasitic load (low x medium/high) and for ultrasound parameters. Furthermore, analysis of prothrombin time and a platelet count were performed. RESULTS Of the 25 patients, 13 showed increased gamma-glutamyltransferase plasma levels. No significant correlation was found between increased gamma-glutamyltransferase levels and the parasitic load, or between increased enzyme levels and ultrasound alterations. Nor did the prothrombin index or the platelet count differ between the two groups (normal gamma-glutamyltransferase levels and increased gamma-glutamyltransferase levels). CONCLUSION The parasitic load explains no rise in gamma-glutamyltransferase plasma levels in patients with the chronic form of schistosomiasis, and conventional ultrasound is not a sensitive method to detect the alteration suggested by the increased enzyme level in those patients.Background - Liver disorders are the major manifestations of schistosomiasis mansoni. Factors that account for increased concentrations of cholestasis-indicating enzymes in the hepatosplenic form of the disease are unknown. Objective - To assess the correlation between increased g-glutamyltransferase serum levels and both the parasitic load and ultrasound alterations in patients with schistosomiasis. Patients and methods - Twenty-five patients with the chronic form of schistosomiasis were assessed for the presence or absence of increased enzymatic levels, for the parasitic load (low x medium/high) and for ultrasound parameters. Furthermore, analysis of prothrombin time and a platelet count were performed. Results - Of the 25 patients, 13 showed increased g-glutamyltransferase plasma levels. No significant correlation was found between increased g-glutamyltransferase levels and the parasitic load, or between increased enzyme levels and ultrasound alterations. Nor did the prothrombin index or the platelet count differ between the two groups (normal g-glutamyltransferase levels and increased g-glutamyltransferase levels). Conclusion - The parasitic load explains no rise in g-glutamyltransferase plasma levels in patients with the chronic form of schistosomiasis, and conventional ultrasound is not a sensitive method to detect the alteration suggested by the increased enzyme level in those patients.

Anicteric cholangiopathy in schistosomiasis patients

UNLABELLED We previously reported that in anicteric patients with the isolated form of schistosomiasis (without co-morbidities) an ursodeoxycholic acid-sensitive increase in serum gamma-glutamyltransferase activity (gammaGT) occurs. We now describe the presence of cholangiopathy in these patients. METHODS Sixteen adult anicteric patients with the isolated form of schistosomiasis mansoni were carefully selected: nine with increased gammaGT and seven with normal gammaGT. High sensitive C-reactive protein (CRP), to exclude inflammatory status, hyaluronic acid (HA), and other laboratory parameters were determined. The ultrasonographic study measured spleen length, portal vein and splenic vein diameters, and the portal flow. Magnetic resonance cholangiopancreatography (MRCP) images were interpreted by a blind observer. MRCP was deemed abnormal when focal narrowing and/or paucity of second and third order biliary branches and/or irregularities in the contours of biliary pathways were identified. RESULTS Both groups (normal and elevated gammaGT) have preserved hepatic function tests (HA, serum albumin, prothrombin time) and clinical significant portal hypertension (low platelet count and ultrasonographic parameters). MRCP was abnormal in all patients with elevated gammaGT but in only 3 of the 7 patients with normal gammaGT (p=0.003). CONCLUSION Magnetic resonance cholangiopancreatography characterized a cholangiopatic disorder in anicteric patients with the isolated form of schistosomiasis, even preceding laboratory test alterations.