Non-selective ß-blockers improve the correlation of liver stiffness and portal pressure in advanced cirrhosis.

BACKGROUND: Liver stiffness (LS) correlates with portal pressure (hepatic venous pressure gradient, HVPG). However, the dynamic components of portal hypertension (PHT) in advanced cirrhosis may not be adequately assessed by TE. The influence of treatment with non-selective ß-blockers (NSBB) on the correlation of HVPG and LS has not been investigated. METHODS: One hundred and twenty-two patients with esophageal varices were included. LS, hemodynamic parameters, and HVPG were recorded at baseline (BL) and after 6 weeks of treatment with NSBB (FU). The correlation of LS and HVPG was compared to control patients with HVPG ≤ 12 mmHg. RESULTS: Patients with higher Child-Pugh stages (A:88/B:25/C:9) had higher levels of liver stiffness (47.4 ± 16.5 vs. 70.3 ± 7.9 vs. 73.7 ± 2.1 kPa) and HVPG (21 ± 5 vs. 26 ± 5 vs. 26 ± 4 mmHg). The correlation of LS and HVPG was stronger in controls with HVPG ≤ 12 mmHg (R = 0.951; P < 0.0001) than in patients with HVPG > 12 mmHg (R = 0.538; P = 0.0004). The association of HVPG with LS became stronger under treatment with NSBB, which finally restored the linear correlation of HVPG and LS (R = 0.930; P < 0.0001). Forty-three percent (53/122) of patients were hemodynamic responders to NSBB. The improvement in the correlation of LS and HVPG under NSBB was mainly noted in hemodynamic responders (R = 0.864), but not in nonresponders (R = 0.535), whereas changes in LS, heart rate, and MAP were similar in responders and nonresponders. CONCLUSIONS: Targeting the hyperdynamic circulation and the increased splanchnic blood inflow by treatment with NSBB unmasks the linear (mechanical) correlation of HVPG and LS in patients with HVPG > 12 mmHg. Measurement of LS by TE is not a feasible method to assess the dynamic components of PHT.

Effect of virtual endoscopy simulator training on performance of upper gastrointestinal endoscopy in patients: a randomized controlled trial.

BACKGROUND: Skills in gastrointestinal endoscopy mainly depend on experience and practice. Patients upon whom trainees perform their first endoscopic examinations are likely to suffer more discomfort and prolonged procedures. Training on endoscopy simulators may reduce the time required to reach competency in patient endoscopy. PATIENTS AND METHODS: Residents in internal medicine without experience of endoscopy were randomized to a group who trained on a simulator before conventional training (group S) or one that received conventional training only (group C) before starting upper gastrointestinal endoscopy in patients. After endoscopy, discomfort and pain were evaluated by patients, who were blind to the beginners' training status. Results in terms of time, technique (intubation, pyloric passage, J-maneuver), and diagnosis of pathological entities were evaluated by experts. RESULTS: From 2003 to 2007, 28 residents were enrolled. Comparing group S with group C in their first ten endoscopic examinations in patients, time taken to reach the duodenum (239 seconds (range 50 - 620) vs. 310 seconds (110 - 720; P < 0.0001) and technical accuracy ( P < 0.02) were significantly better in group S. Diagnostic accuracy did not differ between the groups. Fourteen residents (7 simulator-trained, 7 not simulator-trained) continued endoscopy training. After 60 endoscopic examinations, investigation time was still shorter in group S. Technical and diagnostic accuracy improved during on-patient training in both groups; here differences between groups were no longer observable. There were no significant differences in discomfort and pain scores between the groups after 10 and after 60 endoscopies. Discomfort and pain were higher than for endoscopy performed by experts. CONCLUSION: This randomized controlled trial shows that virtual simulator training significantly affects technical accuracy in the early and mid-term stages of endoscopic training. It helps reduce the time needed to reach technical competency, but clinically the effect is limited. Simulator training could be useful in an endoscopy training curriculum but cannot replace on-patient training.

[Antibiotic prophylaxis in gastrointestinal endoscopy--recommendations of the Austrian Society of Gastroenterology and Hepatology]. / Antibiotikaprophylaxe in der gastrointestinalen Endoskopie--Empfehlungen der Österreichischen Gesellschaft für Gastroenterologie und Hepatologie.

The recommendations of the Austrian Society of Gastroenterology and Hepatology (ÖGGH) for antibiotic prophylaxis in gastrointestinal endoscopy of the year 2002 have been updated in accord with the recently published guidelines of the American Society of Gastrointestinal Endoscopy (ASGE) and the American Heart Association (AHA). Antibiotic prophylaxis for any endoscopic intervention to prevent infectious endocarditis is no longer necessary. Moreover, the prophylactic use of antibiotics for ERCP without biliary obstruction and ERCP with obstruction and a likelihood of complete drainage is no longer recommended. For ERCP with obstruction and anticipated incomplete drainage, a full course of antibiotics should be administered to prevent cholangitis. For the prevention of local infections antibiotics are useful prior to endoscopic puncturing, contrasting or drainage of cystic lesions as well as just before application of a PEG tube. In cirrhotic patients with GI bleeding antibiotic prophylaxis should be started as early as possible and be administered for several days.

Suppression of haematopoiesis during therapy of chronic hepatitis C with different interferon alpha mono and combination therapy regimens.

BACKGROUND: Treatment of chronic hepatitis C with interferon (IFN)-alpha and ribavirin has haematotoxic effects. We evaluated the effects of four different IFN/IFN-ribavirin treatment regimens on haematopoiesis. METHODS: Haematopoiesis was studied in 133 patients with chronic hepatitis C receiving IFN-alpha2b alone (group A) or in combination with ribavirin (group B), pegylated IFN-alpha2a (group C), or pegylated IFN-alpha2b (group D) in combination with ribavirin. RESULTS: At week 4, haemoglobin levels were diminished in all groups receiving combination therapy. In the monotherapy group, haemoglobin decreased slightly after eight weeks. In all groups, haemoglobin remained diminished throughout therapy. In all patients, leucocytes (while blood cells) decreased after four weeks and remained low during treatment. Platelets (peripheral platelet count (PPC)) were decreased in all groups after four weeks and remained below baseline levels during therapy in group A, C, and D whereas in group B PPC recovered early and reached baseline levels at week 16 of therapy. Concomitantly with the decreases in haemoglobin and PPC, erythropoietin increased in all groups receiving combination therapy and thrombopoietin in all groups. Patients treated with pegylated IFN-alpha2a and those who received pegylated IFN-alpha2b combination therapy differed only in leucopoiesis, whereas erythropoiesis and thrombopoiesis were comparable. CONCLUSION: IFN-alpha based therapies are associated with a decrease in all three haematopoietic lineages, irrespective of the type of therapy used. The stronger suppressive effect of pegylated IFN-alpha2a on leucopoiesis could be due to a dose effect. Overall, concentrations of endogenous haematopoietic growth factors are increased but can only partially alleviate haematotoxicity. Potential uses of exogenous haematopoietic growth factors and their impact on the virological response need to be explored.

Short- and long-term effects of therapy with interferon-alpha and pegylated interferon-alpha/ribavirin on platelet plug formation and von Willebrand factor release in patients with chronic hepatitis C.

BACKGROUND: A pegylated interferon-alpha-induced decrease in platelet counts may become a limiting factor for continuation of therapy. AIM: To evaluate the effect of pegylated interferon-alpha administration on platelet plug formation and von Willebrand factor antigen release in patients with chronic hepatitis C. METHODS: Thirty patients with chronic hepatitis C (genotype 1; fibrosis 1-3: n = 16, cirrhosis: n = 14) received a single dose of 9 MU interferon-alpha2a, followed by weekly administration of 180 mug of pegylated interferon-alpha2a/ribavirin for 48 weeks. Platelet counts, platelet function (collagen-epinephrine-induced closure time) and von Willebrand factor antigen were measured. RESULTS: Platelet counts and collagen-epinephrine-induced closure time decreased by 13% and 16%, respectively, 24 h after the first dose of interferon-alpha2a, and von Willebrand factor antigen levels increased by 31% (P < 0.01) compared with baseline. During a 48-week observation period, platelet counts decreased by a maximum of 33% (P < 0.001), von Willebrand factor antigen levels increased by 69% (P < 0.001) whereas collagen-epinephrine-induced closure time did not change. In noncirrhotic patients, the increase of von Willebrand factor antigen levels was maintained throughout therapy without a change in collagen-epinephrine-induced closure time. In contrast, in cirrhotics, von Willebrand factor antigen levels did not increase, while collagen-epinephrine-induced closure time was prolonged. CONCLUSION: Single-dose interferon-alpha decreases platelet counts but improves platelet function, possibly by the release of von Willebrand factor antigen. Accordingly, long-term antiviral treatment had no effect on collagen-epinephrine-induced closure time, despite the decrease in platelet count in noncirrhotic patients. Such a compensation of decreased platelet counts by increased von Willebrand factor antigen level did not occur in cirrhotics.

Erythropoietin increases platelet reactivity and platelet counts in patients with alcoholic liver cirrhosis: a randomized, double-blind, placebo-controlled study.

BACKGROUND: Patients with liver cirrhosis have a complex haemostasis disturbance including thrombocytopenia and abnormal bleeding time. Erythropoietin is the primary stimulator for erythrocyte production and also induces megakaryocyte formation. In healthy men erythropoietin increased platelet count and platelet reactivity. AIM: As patients with liver cirrhosis often undergo invasive procedures, we were interested to study whether erythropoietin could improve platelet function in addition to thrombocytopenia. METHODS: In total, 22 thrombocytopenic (platelet counts < 120 g/L) patients with alcoholic liver cirrhosis received either 100 IE/kg erythropoietin or placebo on days 1, 3 and 5 in a 2:1 randomized, placebo-controlled double-blind fashion. Platelet counts and platelet reactivity (activator-stimulated expression of P-selectin on platelets measured by flow cytometry) were determined on study days 1, 3, 5 and 9. RESULTS: Median platelet count was 80 g/L which is borderline for major elective surgical interventions. Baseline values were not different between groups (P > 0.05). Treatment with erythropoietin increased platelet count by 25% (P = 0.01) and platelet reactivity twofold (P < 0.01) vs. baseline. The increase in platelet count vs. baseline was more pronounced in patients with platelet counts <80 g/L. No significant effect was observed in the placebo group. CONCLUSIONS: Treatment with erythropoietin significantly increased platelet counts and platelet reactivity in patients with alcoholic liver cirrhosis. Preoperative treatment with erythropoietin is therefore expected to yield higher platelet levels and better platelet function.

Rofecoxib exerts no effect on platelet plug formation in healthy volunteers.

OBJECTIVE: Although rofecoxib has very high selectivity for cyclo-oxygenase 2 (COX-2), supratherapeutic rofecoxib concentrations (> 1000 mg) inhibit purified human COX-1 in vitro and TXB2 formation in vivo. It is therefore possible that higher doses of rofecoxib may affect platelet function. This could be important if rofecoxib is given to thrombocytopenic patients. In these cases, already moderate inhibition of platelet function could precipitate bleeding complications. We therefore set out to investigate the influence of rofecoxib on platelet function in healthy volunteers. METHODS: We set up a balanced-randomised, double-blind, placebo-controlled, two way cross-over study. Peripheral blood was withdrawn from 42 healthy volunteers before and 3 hours after intake of 50, 250, 500 mg of rofecoxib or placebo (n = 14 per group). Platelet function was assessed by a platelet function analyzer (PFA-100) which measures collagen-epinephrine induced closure time (CEPI-CT) under shear stress. RESULTS: CEPI-CT increased by 14% (p = 0.002) and 11% (p = 0.003) three hours after intake of placebo and rofecoxib at dosages of up to 500 mg, respectively. The increase in CEPI-CT versus baseline was not significantly different in the placebo period compared with the active treatment periods (n = 42, p > 0.05). CONCLUSIONS: Rofecoxib does not impair platelet function. Thus, rofecoxib appears to be a valuable analgetic and antipyretic agent in the therapy of patients at risk for bleeding.

Impaired platelet function among platelet donors.

BACKGROUND: Platelet transfusions are effective for the prevention and treatment of bleeding in patients with disorders of platelet number and/or function. In recent years plateletpheresis concentrates have outnumbered pooled platelet concentrates, albeit with significant differences between nations. Thus, the platelet quality of individual donors has become increasingly important. The aim of this study was to gain an estimate for the prevalence of impaired platelet function among platelet donors. STUDY DESIGN AND METHODS: We determined the inter-donor variability in platelet plug formation with a PFA-100 analyzer, the prevalence of impaired thromboxane formation, and effects of the density in alpha2 integrin polymorphism and density. RESULTS: (i) Collagen-epinephrine induced closure time (CEPI-CT) showed a great inter-subject variability in platelet donors and was higher than in healthy controls (p = 0.008). One-fifth of donors had abnormal CEPI-CT values and 11% exceeded >300 s (max measurable value). (ii) Decreased serum thromboxane B2 levels were found in 9% of all donors, compatible with surreptitious intake of cyclooxygenase inhibitors or with an aspirin-like defect. CEPI-CT correlated inversely with TxB2-levels in donors and controls. (iii) The density of the alpha2-integrin correlated negatively with CEPI-CT and CADP-CT values in controls, but was not responsible for the observed impaired platelet function in donors. (iv) Finally, the ABO blood group system modulates closure times. CONCLUSION: In sum, a large number of platelet donors present with prolonged closure times. Decreased thromboxane formation and frequent platelet donation partly account for this observation.

Fy phenotype and gender determine plasma levels of monocyte chemotactic protein.

BACKGROUND: In vitro studies indicate that the Fy blood group system antigens serve as receptors for chemokines such as monocyte chemotactic protein-1 (MCP-1) and RANTES. However, it is unclear whether subjects with the Fy(a-b-) phenotype exhibit altered clearance and hence altered plasma levels of chemo-kines, because they still express Fy on endothelial cells. STUDY DESIGN AND METHODS: To clarify a possible in vivo role of Fy on RBCs in the regulation of chemo-kine levels, healthy young volunteers of common Fy phenotypes were compared in a cross-sectional study. RESULTS: More than 90 percent of the 34 subjects of African origin were Fy(a-b-), one black volunteer was Fy(a+b-), and two were Fy(a-b+). As expected, all 65 white volunteers were positive for either Fy(a) and/or Fy(b). Unexpectedly, persons expressing either Fy(a) and/or Fy(b) had significantly higher plasma levels of MCP-1 than Fy(a-b-) volunteers (women: 154 vs. 110 ng/L, p<0.01; men: 179 vs. 169 ng/L, p = 0.03). Surprisingly, plasma levels of MCP-1 were found to be sex-dependent: median MCP-1 levels averaged 180 ng per L in men but only 139 ng per L in women (p<0.001). Further, MCP-1 levels decreased significantly throughout the menstrual cycle of 18 women studied longitudinally. CONCLUSION: MCP-1 levels are about 30 percent higher in men than in premenopausal women, and MCP-1 levels are also higher in persons with RBCs expressing Fy antigens than in Fy(a-b-) persons. These findings have direct implications for the concept and interpretation of clinical studies measuring MCP-1 levels; the role of the observed differences in MCP-1 levels for the pathogenesis of MCP-1-dependent diseases, such as atherosclerosis, merits further investigation.

High levels of reticulated platelets and thrombopoietin characterize fetal thrombopoiesis.

To characterize fetal thrombopoiesis, we determined plasma thrombopoietin (TPO) and glycocalicin levels, platelet counts and reticulated platelets (RP) of fetuses and compared them with the respective values of their mothers. Percutaneous umbilical vein sampling in abnormal pregnancies revealed twofold higher thrombopoietin levels and 20-fold higher reticulated platelet counts, but lower levels of glycocalicin in fetuses compared with their mothers (P < 0.05). Neither the expression of platelet glycoprotein Ib and IIb on platelets nor the platelet counts were different between mothers and their fetuses. These data indicate enhanced thrombopoiesis and/or increased platelet turnover in fetuses.

Cell type-specific variations in the induction of hsp70 in human leukocytes by feverlike whole body hyperthermia.

Fever has been associated with shortened duration and improved survival in infectious disease. The mechanism of this beneficial response is still poorly understood. The heat-inducible 70-kDa heat shock protein (Hsp70) has been associated with protection of leukocytes against the cytotoxicity of inflammatory mediators and with improved survival of severe infections. This study characterizes the induction of Hsp70 by feverlike temperatures in human leukocytes in vitro and in vivo. Using flow cytometry, Hsp70 expression was determined in whole blood samples. This approach eliminated cell isolation procedures that would greatly affect the results. Heat treatment of whole blood in vitro for 2 hours at different temperatures revealed that Hsp70 expression depends on temperature and cell type; up to 41 degrees C, Hsp70 increased only slightly in lymphocytes and polymorphonuclear leukocytes. However, in monocytes a strong induction was already seen at 39 degrees C, and Hsp70 levels at 41 degrees C were 10-fold higher than in the 37 degrees C control. To be as close as possible to the physiological situation during fever, we immersed healthy volunteers in a hot water bath, inducing whole body hyperthermia (39 degrees C), and measured leukocyte Hsp70 expression. Hsp70 was induced in all leukocytes with comparable but less pronounced cell type-specific variations as observed in vitro. Thus, a systemic increase of body temperature as triggered by fever stimulates Hsp70 expression in peripheral leukocytes, especially in monocytes. This fever-induced Hsp70 expression may protect monocytes when confronted with cytotoxic inflammatory mediators, thereby improving the course of the disease.

Granulocyte colony-stimulating factor (G-CSF) downregulates its receptor (CD114) on neutrophils and induces gelatinase B release in humans.

Despite the increasing use of granulocyte colony-stimulating factor (G-CSF) for the mobilization of stem cells and neutrophils, its pharmacodynamic actions are not fully understood. Because of the roles of G-CSF and gelatinase B in leucokinetics, we set out to characterize the interaction of G-CSF with its receptor in humans and its effects on gelatinase B release. G-CSF was infused at bolus doses of 1 microg/kg and 5 microg/kg, and compared to placebo and dexamethasone (1 mg/kg b.i.d), which enhances the plasma levels of endogenous G-CSF. The study was randomized, double-blind, four-way crossover, in eight healthy male volunteers. G-CSF dose-independently induced profound neutropenia (> 95%) within minutes and downregulated its own receptor (CD114) on neutrophils by 75%. The G-CSF/CD114 interaction dose-independently induced degranulation of neutrophils as evidenced by a 300-400% increase in CD11b expression. Degranulation induced up to a 10-fold increase in plasma levels of gelatinase B, an enzyme known to precipitate neutropenia and subsequent neutrophilia in animals. In this study, it was shown that G-CSF downmodulates CD114 expression on the surface of neutrophils in humans and the consequent degranulation enhances gelatinase B release into plasma, which may contribute to mobilization of neutrophils or stem cells.

Inhibitory activity of aspirin on von Willebrand factor-induced platelet aggregation.

The effect of aspirin (ASA) on vWF induced platelet - platelet interaction is unknown. We therefore tested the response of platelets to von Willebrand factor (vWF) coated beads induced platelet aggregation before and after i.v. and oral ASA. 1000 mg ASA was infused to 10 healthy individuals and after a wash-out period 7 volunteers received 100 mg ASA orally over a period of 11 days. Prior to ASA and in regular intervals thereafter we tested the reactivity to vWF-coated beads to assess platelet adhesion/aggregation and the fade-out time of ASA effects on platelets. Considerable interindividual variability in response to vWF-coated beads was observed, both before ASA and after treatment with ASA. The maximal response to vWF-coated beads (Tmax), the time lag, and the slope of the curve were significantly affected by i.v. ASA, whereas 100 mg of ASA had only inconstant effect on Tmax and slope. The absolute reduction of Tmax after ASA depended on the pre-ASA level, while the percentage of the reduction was similar in all individuals. Thus, platelet aggregation induced by vWF-coated beads is impaired by ASA. Furthermore, our data indicate a large interindividual variability of the response to ASA shortly after treatment induction, which becomes more constant after prolonged treatment.

Endotoxin down-modulates granulocyte colony-stimulating factor receptor (CD114) on human neutrophils.

During infection, the development of nonresponsiveness to granulocyte colony-stimulating factor (G-CSF) may be influenced by the down-modulation of G-CSF receptor (G-CSFR) by cytokines. This down-modulation was studied during experimental human endotoxemia. Healthy volunteers received either 2 ng/kg endotoxin (lipopolysaccharide [LPS], n=20) or placebo (n=10) in a randomized, controlled trial. Endotoxin infusion increased the mean fluorescence intensity of the neutrophil activation marker CD11b >300% after 1 h (P<.001 vs. placebo). LPS infusion down-modulated G-CSFR expression in as early as 60 min (-17%; P=.001 vs. placebo). Down-modulation was almost maximal at 90 min and persisted for 6 h (-50% from baseline; P<.0001 vs. placebo). Plasma levels of G-CSF started to increase only after G-CSFR down-modulation had occurred and peaked 37-fold above baseline at 4 h (P<.0001 vs. placebo). In conclusion, LPS down-modulates G-CSFR expression in humans, which may render neutrophils less responsive to the effects of G-CSF and, thereby, compromise host defense mechanisms.

Monitoring of aspirin (ASA) pharmacodynamics with the platelet function analyzer PFA-100.

BACKGROUND: Anti-platelet drug therapy is currently performed without monitoring, because the established method of platelet aggregometry is cumbersome. The recently developed platelet function analyzer PFA-100 measures shear stress dependent, collagen epinephrine (CEPI) and collagen adenosine diphosphate (CADP) induced platelet plug formation. As the PFA-100 provides a valuable tool to detect patients with platelet dysfunction more efficiently and cost-effectively than aggregometry, we investigated its potential to monitor the efficacy of aspirin treatment. METHODS: All healthy volunteers (n = 10) received a fractionated infusion of L-aspirin to establish individual dose-response curves. Further, in a randomized, double-blind, placebo controlled two-way cross over study the same volunteers received either 50 or 100 mg aspirin/day p.o. for a period of 11 days to determine the day-to-day variability CEPI induced closure time (CT) under constant intake of low dose aspirin, and to compare the efficacy of those two doses. RESULTS: Intra- and intersubject variability of CEPI-CT averaged 9% and 22%, respectively. Seven volunteers exceeded the maximum of CEPI-CT (>300 s) already after infusion of 100 mg L-aspirin. Intake of 100 mg of aspirin elicited a more rapid onset of effect than 50 mg, which was only significant on days 3 and 4 of aspirin intake. The aspirin induced CEPI-CT prolongation correlated positively with basal CEPI-CT values (r = 0.86; p = 0.001) and were strongly dependent on von Willebrand Factor levels (r = -0.9; p = 0.001). CONCLUSION: Thus, the PFA-100 system appears suitable to demonstrate an aspirin-induced platelet effect in a longitudinal study, and may be adequate to monitor a patient's compliance. However, prospective trials have to be conducted to demonstrate whether the EPI-CT achieved under ASA-intake has predictive value for cardiovascular outcome.

Systemic inflammation increases shear stress-induced platelet plug formation measured by the PFA-100.

The PFA-100 measures platelet plug formation under shear stress and is strongly dependent on von Willebrand Factor (VWF) levels in plasma. We therefore hypothesized that elevated VWF levels, possibly as a result of acute inflammation, adversely influence PFA-100 results. Healthy volunteers received either 2 ng/kg endotoxin or placebo in a randomized controlled trial. Four hours after endotoxin (but not placebo) infusion VWF levels increased by 85%, collagen epinephrine-induced closure time (CT) decreased by 47% and collagen ADP-CT decreased by 38% (P < 0.0001) respectively. In conclusion, systemic inflammation has a major impact on the results obtained by PFA-100 and may confound interpretation of platelet function.