Different kinetics of HBV and HCV during haemodialysis and absence of seronegative viral hepatitis in patients with end-stage renal disease.

BACKGROUND: Hepatitis C virus (HCV) and hepatitis B virus (HBV) infections are common in haemodialysis units. Moreover, some studies reported seronegative cases of viral hepatitis. We and others have previously shown an HCV RNA decline during haemodialysis; however, limited data on HBV viraemia during haemodialysis are available. METHODS: A total of 142 haemodialysis patients participated in this study, 11 were anti-HCV positive and 7 were HBsAg positive. HCV RNA and HBV DNA were determined in all patients irrespective of hepatitis serology. HBV DNA, HCV RNA, HBsAg and HCV core antigen (HCVcoreAg) were quantified repeatedly in anti-HCV- and HBsAg-positive patients before and after haemodialysis. RESULTS: No case of seronegative viral hepatitis could be identified. HCV RNA was detected in 9 of the 11 anti-HCV-positive patients, while HBV DNA tested positive in all 7 HBsAg-positive patients. A decrease of HCVcoreAg was observed during four dialysis sessions in 8/9 patients (-24.4 ± 22.7%, P < 0.001) parallelled by HCV RNA decline in most individuals (-10.1 ± 48.6%, P = 0.22). In contrast, HBV DNA and HBsAg declined only in 1/7 patients during all four independent measurements. The remaining six patients showed heterogeneous patterns of HBV DNA and HBsAg before and after haemodialysis without a significant change in mean HBV DNA and HBsAg levels (+14 ± 60.6% and -0.2 ± 25.3%, P > 0.05, respectively). HCVcoreAg correlated strongly with HCV RNA (r = 0.937; P < 0.001, n = 72), while there was no correlation between HBV DNA and HBsAg (r = -0.234; P = 0.131, n = 43). CONCLUSIONS: Seronegative viral hepatitis is rare in German maintenance haemodialysis patients. HCV RNA and HCVcoreAg decline during haemodialysis indicating a potential beneficial effect of haemodialysis during antiviral therapy of hepatitis C, which does not apply to HBV infection.

Circulating concentrations of follistatin-like 1 in healthy individuals and patients with acute coronary syndrome as assessed by an immunoluminometric sandwich assay.

BACKGROUND: Follistatin-like 1 (FSTL1) is a 308-amino acid secreted glycoprotein. Tissue levels of FSTL1 are induced in animal models and patients with chronic inflammatory and cardiovascular disease. We hypothesized that FSTL1 can be measured in the human circulation and used as a biomarker in acute coronary syndrome (ACS). METHODS: We developed an immunoluminometric assay (ILMA), assessed the preanalytic characteristics of FSTL1, and determined circulating FSTL1 concentrations in 120 apparently healthy individuals and 216 patients with ACS. RESULTS: The assay had a limit of detection of 0.17 microg/L, limit of quantification of 1.02 microg/L, intraassay imprecision of < or =12.7%, and interassay imprecision of < or =15.4%. Selectivity was demonstrated with size-exclusion chromatography and lack of cross-reactivity with related proteins. The assay was not appreciably influenced by unrelated biological substances. FSTL1 in serum or whole blood was stable at room temperature for 48 h and was resistant to 4 freeze-thaw cycles. Measured FSTL1 concentrations in citrated plasma and heparin-treated plasma were 18% and 17% lower, respectively, than concentrations measured in serum. Apparently healthy individuals presented with a median FSTL1 serum concentration of 7.18 (range 1.06-18.49) microg/L. Serum FSTL1 concentrations were increased in ACS and related to the risk of all-cause mortality during follow-up. CONCLUSIONS: The ILMA permits detection of FSTL1 in human serum and plasma. We expect that the favorable preanalytic characteristics of FSTL1 and the reference limits defined here for apparently healthy individuals will facilitate future studies of FSTL1 as a biomarker in various disease settings, including ACS.

Prognostic value of growth-differentiation factor-15 in patients with non-ST-elevation acute coronary syndrome.

BACKGROUND: Growth-differentiation factor-15 (GDF-15) is a member of the transforming growth factor-beta cytokine superfamily that is induced in the heart after ischemia-and-reperfusion injury. Circulating levels of GDF-15 may provide prognostic information in patients with non-ST-elevation acute coronary syndrome. METHODS AND RESULTS: Blood samples were obtained on admission from 2081 patients with acute chest pain and either ST-segment depression or troponin elevation who were included in the Global Utilization of Strategies to Open Occluded Arteries (GUSTO)-IV Non-ST-Elevation Acute Coronary Syndrome trial and from a matching cohort of 429 apparently healthy individuals. GDF-15 levels were determined by immunoradiometric assay. Approximately two thirds of patients presented with GDF-15 levels above the upper limit of normal in healthy controls (1200 ng/L); one third presented with levels >1800 ng/L. Increasing tertiles of GDF-15 were associated with an enhanced risk of death at 1 year (1.5%, 5.0%, and 14.1%; P<0.001). By multiple Cox regression analysis, only the levels of GDF-15 and N-terminal pro-B-type natriuretic peptide, together with age and a history of previous myocardial infarction, contributed independently to 1-year mortality risk. Receiver operating characteristic curve analyses further illustrated that GDF-15 is a strong marker of 1-year mortality risk (area under the curve, 0.757; best cutoff, 1808 ng/L). At this cutoff value, GDF-15 added significant prognostic information in patient subgroups defined by age; gender; time from symptom onset to admission; cardiovascular risk factors; previous cardiovascular disease; and the risk markers ST-segment depression, troponin T, N-terminal pro-B-type natriuretic peptide, C-reactive protein, and creatinine clearance. CONCLUSIONS: GDF-15 is a new biomarker of the risk for death in patients with non-ST-elevation acute coronary syndrome that provides prognostic information beyond that provided by established clinical and biochemical markers.

Circulating concentrations of growth-differentiation factor 15 in apparently healthy elderly individuals and patients with chronic heart failure as assessed by a new immunoradiometric sandwich assay.

BACKGROUND: Growth-differentiation factor 15 (GDF15) is a member of the transforming growth factor beta (TGF-beta) cytokine superfamily. There has been increasing interest in using circulating GDF15 as a biomarker in patients, for example those with cardiovascular disease. METHODS: We developed an IRMA that uses a polyclonal, affinity chromatography-purified goat antihuman GDF15 IgG antibody, assessed the preanalytic characteristics of GDF15, and determined circulating GDF15 concentrations in 429 apparently healthy elderly individuals and 153 patients with chronic heart failure (CHF). RESULTS: The assay had a detection limit of 20 ng/L, an intraassay imprecision of < or =10.6%, and an interassay imprecision of < or =12.2%. Specificity was demonstrated with size-exclusion chromatography, parallel measurements with polyclonal and monoclonal anti-GDF15 antibody, and lack of cross-reactivity with TGF-beta. The assay was not appreciably influenced by the anticoagulant matrix or unrelated biological substances. GDF15 was stable at room temperature for 48 h and resistant to 4 freeze-thaw cycles. Apparently healthy, elderly individuals presented with a median GDF15 concentration of 762 ng/L (25th-75th percentiles, 600-959 ng/L). GDF15 concentrations were associated with age and with cystatin C and C-reactive protein concentrations. CHF patients had increased GDF15 concentrations that were closely related to disease severity. CONCLUSION: The IRMA can detect GDF15 in human serum and plasma with excellent sensitivity and specificity. The reference limits and confounding variables defined for apparently healthy elderly individuals and the favorable preanalytic characteristics of GDF15 are expected to facilitate future studies of GDF15 as a biomarker in various disease settings, including CHF.