Platelet Hyperaggregability is Highly Prevalent in Patients With Chronic Kidney Disease

Background:

Platelet hyperaggregation is known to be associated with arterial and venous thromboembolic events. The prevalence of platelet hyperaggregation in patients with chronic kidney disease (CKD) has not been described to date.

Methods:

Platelet hyperaggregation in patients with renal disease was defined by comparison of platelet aggregation patterns to non-CKD patients without thromboembolic disorders and healthy controls.

Results:

Among the 30 hemodialysis patients and 34 renal transplant recipients, 20 (67%) and 28 (82%) showed significantly decreased median Δ-epinephrine aggregation and increased 0.5 mol/L epinephrine response (65% and 54%) compared to healthy controls and non-CKD patients. In concordance to the laboratory finding of platelet hyperaggregability, renal transplant recipients showed a high rate of thromboembolic events (normal platelet aggregation: 0 events and platelet hyperaggregation: 30 events in 13 of 28 patients).

Conclusions:

Patients with CKD exhibit a hitherto unappreciated high prevalence of platelet hyperaggregability indicating sticky platelet syndrome. Laboratory testing of platelet hyperaggregability may supplement the assessment of thromboembolic complications in patients with CKD.

Serum NT-proCNP concentrations are elevated in patients with chronic liver diseases and associated with complications and unfavorable prognosis of cirrhosis

OBJECTIVES

C-type natriuretic peptide (CNP) might be an important regulator of vasodilatation, fluid and sodium balance in liver cirrhosis. We aimed at assessing its regulation and prognostic relevance in liver disease patients.

DESIGN AND METHODS

We analyzed NT-proCNP serum levels in 193 patients with chronic liver diseases and 43 healthy controls.

RESULTS

Serum NT-proCNP concentrations were significantly elevated in liver disease patients compared to healthy controls, with highest levels in established hepatic cirrhosis, independent of disease etiology. NT-proCNP was associated with complications of liver diseases and portal hypertension, namely ascites, esophageal varices and hepatic encephalopathy. Circulating NT-proCNP correlated inversely with renal function. Importantly, elevated NT-proCNP levels were identified as a predictor of mortality or necessity for transplantation. NT-proCNP levels >2 pmol/L indicated adverse prognosis (sensitivity 66.7%, specificity 72.8%, RR 5.4 [95%-CI 2.6-11.2]).

CONCLUSIONS

Serum NT-proCNP is elevated in advanced liver diseases and has prognostic value in cirrhotic patients.

Increased liver stiffness denotes hepatic dysfunction and mortality risk in critically ill non-cirrhotic patients at a medical ICU

INTRODUCTION

Hepatic dysfunction is a common finding in critically ill patients on the ICU and directly influences survival. Liver stiffness can be measured by the novel method of transient elastography (fibroscan) and is closely associated with hepatic fibrosis in patients with chronic liver disease, but also is increased in patients with acute hepatitis, acute liver failure and cholestasis. We investigated liver stiffness as a potentially useful tool for early detection of patients with hepatic deterioration and risk stratification with respect to short- and long-term mortality.

METHODS

We prospectively evaluated 108 consecutive critically ill patients at our medical intensive care unit (ICU) with subsequent longitudinal liver stiffness measurements (admission, Day 3, Day 7 and weekly thereafter) during the course of ICU treatment. Outcome was followed after discharge (median observation time 237 days).

RESULTS

Liver stiffness could be reliably measured in 71% of ICU patients at admission (65% at Day 3, 63% at Day 7). Critically ill patients (n = 108) had significantly increased liver stiffness compared to sex- and age-matched standard care patients (n = 25). ICU patients with decompensated cirrhosis showed highest liver stiffness, whereas other critical diseases (for example, sepsis) and comorbidities (for example, diabetes, obesity) did not impact stiffness values. At admission to the ICU, liver stiffness is closely related to hepatic damage (liver synthesis, cholestasis, fibrosis markers). During the course of ICU treatment, fluid overload (renal failure, volume therapy) and increased central venous pressure (mechanical ventilation, heart failure) were major factors determining liver stiffness. Liver stiffness values > 18 kilopascal (kPa) at ICU admission were associated with increased ICU and long-term mortality, even in non-cirrhotic patients.

CONCLUSIONS

Considering that liver stiffness cannot be validly measured in about 30% of ICU patients, transient elastography performed at ICU admission might be a useful tool to early identify liver dysfunction and predict mortality in critically ill patients at a medical ICU.

Circulating soluble urokinase plasminogen activator receptor is stably elevated during the first week of treatment in the intensive care unit and predicts mortality in critically ill patients

INTRODUCTION

suPAR is the soluble form of the urokinase plasminogen activator receptor (uPAR), which is expressed in various immunologically active cells. High suPAR serum concentrations are suggested to reflect the activation of the immune system in circumstances of inflammation and infection, and have been associated with increased mortality in different populations of non-intensive care patients. In this study we sequentially analyzed suPAR serum concentrations within the first week of intensive care in a large cohort of well characterized intensive care unit (ICU) patients, in order to investigate potential regulatory mechanisms and evaluate the prognostic significance in critically ill patients.

METHODS

A total of 273 patients (197 with sepsis, 76 without sepsis) were studied prospectively upon admission to the medical intensive care unit (ICU), on Day 3 and Day 7, and compared to 43 healthy controls. Clinical data, various laboratory parameters as well as investigational inflammatory cytokine profiles were assessed. Patients were followed for approximately one year.

RESULTS

Upon admission to the ICU suPAR serum concentrations were elevated in critically ill patients as compared with healthy controls. In sepsis patients suPAR levels were higher than in non-sepsis patients (with or without systemic inflammatory response syndrome (SIRS)). During the first week after admission to the ICU serum suPAR concentrations remained stably elevated. suPAR serum concentrations measured upon admission were closely and independently correlated to various laboratory parameters, specifically biomarkers of inflammation (tumor necrosis factor (TNF), C-reactive protein (CRP)), hepatic and renal dysfunction. High suPAR levels at admission and at Day 3 were a strong independent predictor for both ICU and long-term mortality in critically ill patients.

CONCLUSIONS

In sepsis and non-sepsis patients suPAR serum concentrations are increased upon admission to the ICU, likely reflecting the activation state of the immune system, and remain stably elevated in the initial course of treatment. Low suPAR levels are a positive predictor of ICU- and overall survival in critically ill patients, including sepsis and non-sepsis patients. Aside from its value as a promising new prognostic biomarker, both experimental and clinical studies are required in order to understand the specific effects and regulatory mechanisms of suPAR in SIRS and sepsis, and may reveal new therapeutic options.

Longitudinal monocyte human leukocyte antigen-DR expression is a prognostic marker in critically ill patients with decompensated liver cirrhosis

BACKGROUND

Critical illness in cirrhotic patients is associated with a poor prognosis and increased susceptibility to infections. Monocyte HLA-DR expression is decreased in cirrhotic patients, but its prognostic value has not been investigated prospectively.

METHODS

Thirty-eight critically ill patients with decompensated liver cirrhosis were included in this prospective study. On admission to the intensive care unit (ICU), inflammatory parameters (C-reactive protein, procalcitonin and lipopolysaccharide-binding protein), interleukin (IL)-10, interferon (IFN)-gamma serum levels, tumour necrosis factor (TNF)-alpha ex vivo stimulation (whole blood assay) and HLA-DR expression on monocytes (FACS analysis) were determined. Immune parameters were furthermore measured every third day until discharge from the ICU or death of the patients.

RESULTS

Intensive care unit mortality of the cirrhotic patients was 34.2%. During admission, TNF ex vivo, IFN-gamma and HLA-DR expression were lower in non-survivors (all P<0.05), while IL-10 levels were increased in non-survivors compared with survivors (P=0.001). However, individual values clearly overlapped between groups. Prospective analysis revealed that monocyte HLA-DR expression remained stable or increased in survivors, but decreased in non-survivors (P=0.002). A decrease in HLA-DR expression between admission and day 3 was strongly associated with decreased IFN-gamma levels and increased ICU mortality (hazard ratio 3.36, P=0.008), mostly owing to late sepsis. This association was independent of the sequential organ failure assessment and model for end-stage liver disease score.

CONCLUSIONS

Here we establish the relative HLA-DR expression (admission/day 3) as a prognostic marker for ICU mortality in critically ill cirrhotic patients. These results may guide the evaluation of immune-modulating therapies in these patients.

The interleukin-6 (IL6)-174 G/C promoter genotype is associated with the presence of septic shock and the ex vivo secretion of IL6

Septic shock is associated with a high mortality and an excessive activation of immune cascades. Interleukin (IL)-6 has been found to be a key cytokine in the pathogenesis of severe sepsis, but the importance of a regulatory polymorphism within the IL6 promoter has been controversial in these patients. The aim of the study was therefore to systematically investigate the IL6-174 G/C promoter genotype with regard to the presence of shock in patients with sepsis, the IL6 serum levels, and the ex vivo secretion of IL6, respectively. Overall, 112 consecutive subjects with severe sepsis and septic shock according to consensus criteria were enrolled. The ex vivo secretion of IL6 after stimulation with lipopolysaccharide (LPS) in a whole blood assay and the IL6 serum concentrations were determined after admission of the patients. Among the 112 subjects with severe sepsis, 85 patients fulfilled the criteria of septic shock. In these patients, the frequency of the mutated C-allele of the IL6 promoter polymorphism was significantly (P = 0.04) higher compared to that in individuals without shock. IL6 serum concentrations were highest in patients with the GG genotype (mean 2209 pg mL(-1)), followed by CG genotype (mean 1113 pg mL(-1)), and lowest in individuals with the CC genotype (mean 256 pg mL(-1)). Interestingly, a significantly (P = 0.005) higher ex vivo secretion of IL6 is detected in heterozygote individuals (535 pg mL(-1)) and patients with the IL6 CC genotype (555 pg mL(-1)) compared to patients with the -174 GG genotype (276 pg mL(-1)). In conclusion, the IL6-174 G/C promoter genotype is associated with shock in patients with sepsis. Functionally, the mutated C-allele is correlated with low IL6 serum concentrations, but a high ex vivo secretion after LPS stimulation. These results further indicate a complex regulation of the expression of IL6 during infection and have implications for the design of immune intervention trials.

The significance of vasodilator-stimulated phosphoprotein for risk stratification of stent thrombosis

Low-response to the P2Y12 adenosine diphosphate (ADP)-receptor antagonist clopidogrel was suggested to correspond to a higher incidence of stent thrombosis (ST). This prospective observational study assessed the capability of two platelet function assays, e.g. direct measurement of the phosphorylation status of vasodilator-stimulated phosphoprotein (VASP) and ADP-induced platelet aggregation for definition of the individual risk to develop ST. Ninety-nine patients with an elevated high risk to develop ST were enrolled. All patients received a dual antiplatelet therapy consisting of 100 mg aspirin and 75 mg clopidogrel during an observation period of six months. Flow cytometry of VASP phosphorylation and densitometrically-determined measurement of ADP-induced platelet aggregation was performed 72-96 hours after stent implantation. These data were related to angiographically confirmed ST. Nine patients suffered from angiographically confirmed ST (9.1%). The meanVASP-platelet reactivity indices (VASP-PRI) and values for ADP-induced platelet aggregation in the ST group were significantly higher (60.8 +/- 13.0 and 60.9 +/- 13.1, respectively) compared to patients without ST (41.3 +/- 14.0 and 50.8 +/- 14.4, P < 0.001 vs. 0.048, respectively). There was a fair correlation between both methods using non-linear regression analysis (r = 0.332). In a multivariate analysis, VASP was the only independent predictor of ST and was superior to previously identified angiographic parameters. Receiver- operator characteristic (ROC) curve analysis revealed a cut-off value for VASP-PRI of <48% to be associated with low risk of ST. In conclusion, determination of VASP phosphorylation is superior to conventional platelet aggregometry and angiographic parameters for assessing the risk of ST. Patients with a VASP-PRI >48% seem to have a significantly increased risk.

Elevation of endoglin (CD105) concentrations in serum of patients with liver cirrhosis and carcinoma

OBJECTIVE

Liver cirrhosis is considered as a premalignant state, as about 80% of hepatocellular carcinoma (HCC) is associated with liver cirrhosis. Although alpha-fetoprotein (AFP) has a high negative predictive value, its sensitivity for detecting HCC is poor. The aim of this study was to evaluate circulating endoglin (CD105) in the serum of patients with liver cirrhosis and at high risk for HCC.

METHODS

CD105 and AFP serum concentrations were measured in 70 healthy and 94 nonliver-diseased controls and 130 patients with chronic liver diseases and HCC, respectively.

RESULTS

Fifty-seven liver cirrhotic patients, 45 patients with liver cirrhosis plus HCC, 19 liver fibrosis patients and nine patients with HCC only were studied. Serum CD105 is significantly elevated in liver cirrhotic patients compared with healthy (P<0.0001) and nonliver-diseased controls (P<0.0001). Patients with liver cirrhosis and HCC show the highest CD105 concentrations being significantly elevated in comparison to liver cirrhosis (P=0.0006) and HCC only (P=0.0134). A stronger positive correlation exists between CD105 and AFP in the patient group suffering from liver cirrhosis and HCC (r=0.479, P=0.0015) than the obtained correlation between both markers in the group of patients diagnosed with liver cirrhosis alone (r=0.358, P=0.0073). The logistic regression model identified CD105 as an independent marker (P=0.0077, odds ratio 1.3).

CONCLUSION

CD105 has the potential to be a novel complementary biomarker that has some important bearing on the risk assessment for development of HCC in cirrhotic patients.

Up-regulated eotaxin plasma levels in chronic liver disease patients indicate hepatic inflammation, advanced fibrosis and adverse clinical course

BACKGROUND AND AIMS

Recent studies highlight the role of chemokines for the attraction of inflammatory cells in liver injury and fibrogenesis. The CC chemokine ligand 11, eotaxin (CCL11), is up-regulated in senescent human hepatic stellate cells and crucial in animal models of T-cell mediated hepatitis. The aim of this study was to analyze the role of eotaxin in chronic liver disease.

METHODS

Plasma eotaxin levels of 111 patients with chronic liver disease were correlated with clinical presentation, laboratory parameters, liver histology and clinical course in a 6-year follow-up.

RESULTS

Eotaxin concentrations were significantly up-regulated in patients with liver cirrhosis and increased according to Child-Pugh and model of end-stage liver disease (MELD) score. Eotaxin correlated with the hepatic biosynthetic capacity and other inflammatory cytokines. High eotaxin was associated with hepatic necroinflammation and fibrosis in liver histology. In patients with typical clinical complications of cirrhosis, eotaxin was found to be increased. High eotaxin indicated an unfavorable prognosis in 6-year follow-up.

CONCLUSIONS

High eotaxin expression may be involved in the pathogenesis of chronic liver diseases. Plasma eotaxin levels correlate with the degree of liver cirrhosis and could serve as an additional biomarker indicating histological hepatic necroinflammation and fibrosis as well as an adverse clinical course.

Insulin resistance in liver cirrhosis is not associated with circulating retinol-binding protein 4

OBJECTIVE

Retinol-binding protein 4 (RBP4) has been identified as a novel adipokine mediating systemic insulin resistance, and elevated serum RBP4 indicates overt or impending insulin resistance in lean, obese, and type 2 diabetic subjects. As insulin resistance is present in nearly all patients with liver cirrhosis, we evaluated RBP4 in patients with chronic liver disease (CLD).

RESEARCH DESIGN AND METHODS

Serum RBP4 was measured in 111 CLD patients. Ninety-nine age- and sex-matched healthy blood donors served as control subjects. RBP4 gene expression was also quantified in normal and cirrhotic rat liver.

RESULTS

In CLD patients, serum RBP4 was significantly reduced compared with healthy control subjects and closely correlated with the stage of liver cirrhosis. CLD patients without cirrhosis showed normal RBP4 concentrations, which correlated with serum glucose and insulin secretion and inversely correlated with insulin sensitivity. In patients with Child A-C liver cirrhosis, however, RBP4 was not correlated with glucose metabolism or other adipokines, such as adiponectin or resistin, but closely linked to the hepatic biosynthetic capacity, fibrotic changes in liver histology, or clinical complications such as portal hypertension. In an animal model of experimental cirrhosis, hepatic RBP4 gene expression decreased in cirrhotic liver.

CONCLUSIONS

RBP4 appears, unlike in obesity or type 2 diabetes, not to be a relevant systemic factor in the pathogenesis of insulin resistance in liver cirrhosis. Liver function has a tremendous impact on RBP4 levels, and future studies will need to take liver function into account when examining serum RBP4 levels.

Development and multicenter evaluation of the N latex CDT direct immunonephelometric assay for serum carbohydrate-deficient transferrin

BACKGROUND

Carbohydrate-deficient transferrin (CDT) is a promising biomarker of alcohol abuse. We describe the development and multicenter evaluation of N Latex CDT (Dade Behring), an automated, particle-enhanced, homogeneous immunonephelometric assay for directly determining CDT.

METHODS

N Latex CDT uses a monoclonal antibody that recognizes the structure of transferrin glycoforms lacking 1 or 2 complete N-glycans [i.e., disialo-, monosialo-, and asialotransferrins (CDT glycoforms)] in combination with a simultaneous assay for total transferrin. The Dade Behring BN II and BN ProSpec systems automatically calculate the CDT value as a percentage of total transferrin (%CDT). No preanalytical sample treatment is used.

RESULTS

Total imprecision values for serum pools containing 1.8%-8.7% CDT were 3.4%-10.4% (mean, 6.8%). The mean (SD) %CDT for 561 serum samples from healthy control individuals was 1.76% (0.27%; range, 1.01%-2.85%). No marked sex or age differences were noted. The 97.5th percentile was at 2.35%. Transferrin genetic variants did not interfere with measurements. High transferrin concentrations did not falsely increase %CDT values, but increased %CDT values were noted for some samples with transferrin concentrations <1.1 g/L. N Latex CDT results correlated with those of a commercial CDT immunoassay involving column separation (r(2) = 0.862) and an HPLC candidate reference method (r(2) = 0.978).

CONCLUSION

N Latex CDT is the first direct immunoassay for quantifying %CDT in serum. The specificity of N Latex CDT for identifying alcohol abuse may be higher than for immunoassays that use column separation, because transferrin genetic variants do not interfere with measurements.

Saliva collection method affects predictability of serum cortisol

BACKGROUND

Measurement of cortisol is of particular importance for early diagnosis of adrenocorticotropic dysfunction and therapeutic monitoring. Saliva samples clearly present an easily manageable, non-invasive and anytime practicable assessment method of glucocorticoid production. The aims of the present study were to compare salivary cortisol collection method "Salivette" versus "passive drool", salivary cortisol concentrations with calculated free serum cortisol (FSC) and total serum cortisol (TSC) and the prediction of serum cortisol by salivary cortisol.

METHODS

Saliva samples were collected by Sarstedt-Salivette(R) and by passive drooling into plastic tubes. Salivary cortisol, TSC measurements and calculation of FSC concentrations as well were carried out simultaneously in 10 healthy volunteers on two consecutive days at six definite points of time (08.00-23.00).

RESULTS

Significant differences of salivary cortisol concentrations dependent on the saliva collection method (F-test 6.45; p=0.0317) and points of times were found (F-test 41.19; p<0.0001). Stronger overall correlation was observed in Salivette-salivary cortisol vs. TSC (r=0.813) and FSC (r=0.836) as compared to passive drooling. Specifically, more significant correlations were established in Salivettes vs. TSC (8/12 points of time, 66.7%) and FSC (8/12 points of time, 66.7%) than in passive drooling (TSC: 1/12 points of time, 8.3% and FSC: 2/12 points of time, 16.7%). Importantly, cortisol in Salivettes was a better predictor for FSC and TSC than passive drooling.

CONCLUSIONS

Our data indicate that salivary cortisol measurement with Salivettes is a reliable prediction method of total and calculated free serum cortisol levels. Moreover, it is a convenient method for saliva collection, handling and laboratory processing.

Elevated apoptosis-associated cytokeratin 18 fragments (CK18Asp386) in serum of patients with chronic liver diseases indicate hepatic and biliary inflammation

OBJECTIVES

During apoptosis, intermediate filament protein cytokeratin 18 (CK18) is cleaved by caspases at Asp396 which can be specifically detected by the monoclonal antibody M30 (M30-antigen).

DESIGN AND METHODS

M30-antigen serum levels were analyzed in 76 chronic liver diseases (CLD) patients and 62 healthy controls.

RESULTS

M30-antigen levels were significantly elevated in CLD patients (median 296.3 U/L) compared with healthy controls (median 153.5 U/L, P<0.001) and increased with disease severity (Child-Pugh or MELD score). M30-antigen correlated with aminotransferase activities and parameters indicating cholestasis such as bile acids. Highest serum M30-antigen was associated with histologically confirmed severe intrahepatic cholestasis (median 599.1 U/L) or biliary duct inflammation (median 648.0 U/L). Furthermore, in contrast to patients with liver cirrhosis, presence of hepatocellular carcinoma was associated with elevated M30-antigen in patients without cirrhosis.

CONCLUSION

Serum M30-antigen levels are elevated in CLD and correlate with hepatic inflammation as well as cholangitis and cholestasis.

[Elevated concentrations of fecal calprotectin in patients with liver cirrhosis]

BACKGROUND AND OBJECTION: Bacterial translocation from the gut lumen is considered to play an important role in the development of infectious complications in patients with liver cirrhosis. This translocation might be increased by inflammation of the gut mucosa. Calprotectin is a cytoplasmatic protein of neutrophilic granulocytes and is an established marker for the assessment of localized intestinal inflammation. It was the aim of the current study to systematically evaluate a localized intestinal inflammation in patients with liver cirrhosis by means of fecal calprotectin concentrations.

PATIENTS AND METHODS

Fecal calprotectin concentrations were determined in 53 consecutive patients with liver cirrhosis and in 18 subjects without intestinal or liver diseases, who were comparable with respect to age and gender. Patients with diarrhoea, inflammatory bowel disease and a positive stool test for occult blood were excluded from the study. Fecal calprotectin concentrations were measured by a sandwich ELISA. The systemic inflammatory reaction of the patients was assessed by C-reactive protein, white blood cells counts and the serum concentrations of the cytokines IL-6, IL-8 and IL-10.

RESULTS

Fecal calprotectin concentrations were significantly increased in patients with liver cirrhosis (median 37.0 mg/kg) compared to controls patients (median 2.2, P < 0.0001). There were no significant correlations of calprotectin concentrations with systemic inflammatory parameters, like CRP, white blood cell count or serum cytokines. However, fecal calprotectin concentrations were significantly associated with the stage of liver cirrhosis as expressed by the Child-Pugh score ( P < 0.001). A trend towards higher concentrations of calprotectin was found in patients with alcoholic liver cirrhosis ( P = 0.1).

CONCLUSIONS

Patients with liver cirrhosis display elevated fecal calprotectin concentrations as a potential sign of intestinal inflammation. Further studies are warranted to establish a role of calprotectin for the risk assessment of infectious complications secondary to bacterial translocation in patients with liver cirrhosis.