Andreas D. Christ

Incremental value of copeptin for rapid rule out of acute myocardial infarction.

OBJECTIVESnThe purpose of this study was to examine the incremental value of copeptin for rapid rule out of acute myocardial infarction (AMI).nnnBACKGROUNDnThe rapid and reliable exclusion of AMI is a major unmet clinical need. Copeptin, the C-terminal part of the vasopressin prohormone, as a marker of acute endogenous stress may be useful in this setting.nnnMETHODSnIn 487 consecutive patients presenting to the emergency department with symptoms suggestive of AMI, we measured levels of copeptin at presentation, using a novel sandwich immunoluminometric assay in a blinded fashion. The final diagnosis was adjudicated by 2 independent cardiologists using all available data.nnnRESULTSnThe adjudicated final diagnosis was AMI in 81 patients (17%). Copeptin levels were significantly higher in AMI patients compared with those in patients having other diagnoses (median 20.8 pmol/l vs. 6.0 pmol/l, p < 0.001). The combination of troponin T and copeptin at initial presentation resulted in an area under the receiver-operating characteristic curve of 0.97 (95% confidence interval: 0.95 to 0.98), which was significantly higher than the 0.86 (95% confidence interval: 0.80 to 0.92) for troponin T alone (p < 0.001). A copeptin level <14 pmol/l in combination with a troponin T < or =0.01 microg/l correctly ruled out AMI with a sensitivity of 98.8% and a negative predictive value of 99.7%.nnnCONCLUSIONSnThe additional use of copeptin seems to allow a rapid and reliable rule out of AMI already at presentation and may thereby obviate the need for prolonged monitoring and serial blood sampling in the majority of patients. (Advantageous Predictors of Acute Coronary Syndromes Evaluation [APACE]; NCT00470587).

An interleukin 12-related cytokine is up-regulated in ulcerative colitis but not in Crohn's disease

BACKGROUND & AIMSnInterleukin 12 (IL-12) is a heterodimeric, macrophage-derived cytokine that is elevated in Crohns disease (CD). Epstein-Barr virus-induced gene 3 (EBI3) is a recently characterized human glycoprotein that is homologous to the 40-kilodalton chain of IL-12 and forms a heterodimer with the 35-kilodalton chain of IL-12. We investigated the expression of EBI3 in colonic mucosa of normal control subjects, patients with ulcerative colitis (UC), and patients with CD.nnnMETHODSnColonic tissue was analyzed for messenger RNA (mRNA) expression by quantitative polymerase chain reaction and for protein expression by immunohistology and Western blotting.nnnRESULTSnEBI3 mRNA was present in intestinal biopsy specimens from healthy subjects and patients with CD but was elevated only in active UC. EBI3 levels in UC specimens correlated with histological scores of activity and T-cell infiltration. EBI3-positive cells that had a shape consistent with that of macrophages were identified in the lamina propria, and protein was detected by Western blotting.nnnCONCLUSIONSnEBI3 is a novel IL-12-related cytokine that is expressed by macrophage-like cells in normal intestine and CD and has enhanced expression in active UC but not in active CD.

The intestinal epithelial cell : immunological aspects

SummaryIECs likely play an important role in immunological defense mechanism. Apart from being a passive barrier against luminal bacteria, IECs secrete protective and microbiocidal products such as ITF, complement components and cryptdins into the lumen. Moreover, IECs produce secretory component that is essential for the transport of IgA from the lamina propria into the lumen. IECs also have regulatory functions. They express adhesion molecules important in the homing of T cells and other leukocytes, and likely modulate T cell functions in a paracrine way. Furthermore, IECs secrete cytokines, either constitutively or after bacterial challenge, and they express cytokine receptors. Lastly, IECs may play an important role as non-professional antigen-presenting cells by expressing classical MHC class I and class II and non-classical MHC class I molecules on the cell surface. This aspect is particularly intriguing in that IECs also express a FcR that may have a function in luminal antigen sampling.

Sodium chloride vs. sodium bicarbonate for the prevention of contrast medium-induced nephropathy: A randomized controlled trial

AIMSnThe most effective regimen for the prevention of contrast-induced nephropathy (CIN) remains uncertain. Our purpose was to compare two regimens of sodium bicarbonate with 24 h sodium chloride 0.9% infusion in the prevention of CIN.nnnMETHODS AND RESULTSnWe performed a prospective, randomized trial between March 2005 and December 2009, including 258 consecutive patients with renal insufficiency undergoing intravascular contrast procedures. Patients were randomized to receive intravenous volume supplementation with either (A) sodium chloride 0.9% 1 mL/kg/h for at least 12h prior and after the procedure or (B) sodium bicarbonate (166 mEq/L) 3 mL/kg for 1 h before and 1 mL/kg/h for 6 h after the procedure or (C) sodium bicarbonate (166 mEq/L) 3 mL/kg over 20 min before the procedure plus sodium bicarbonate orally (500 mg per 10 kg). The primary endpoint was the change in estimated glomerular filtration rate (eGFR) within 48 h after contrast. Secondary endpoints included the development of CIN. The maximum change in eGFR was significantly greater in Group B compared with Group A {mean difference -3.9 [95% confidence interval (CI), -6.8 to -1] mL/min/1.73 m2, P = 0.009} and similar between groups C and B [mean difference 1.3 (95% CI, -1.7-4.3) mL/min/1.73 m(2), P = 0.39]. The incidence of CIN was significantly lower in Group A (1%) vs. Group B (9%, P = 0.02) and similar between Groups B and C (10%, P = 0.9).nnnCONCLUSIONnVolume supplementation with 24 h sodium chloride 0.9% is superior to sodium bicarbonate for the prevention of CIN. A short-term regimen with sodium bicarbonate is non-inferior to a 7 h regimen. ClinicalTrials.gov Identifier: NCT00130598.

The expression of IL‐12 p40 and its homologue, epstein‐barr virus‐induced gene 3, in inflammatory bowel disease

BackgroundIt has recently been suggested that Crohns Disease (CD) is associated with an exaggerated T helper 1 cytokine response as manifest by increased production of interleukin-12 (IL-12) and interferon-&ggr; (IFN-&ggr;). Epstein-Barr virus-induced gene 3 (EBI3) encodes a 34-kDa glycoprotein that is 27% identical to the p40 unit of IL-12 and has recently been reported to be up-regulated in ulcerative colitis (UC). AimTo determine whether mucosal expression of IL-12 p40 or EBI3 correlates with inflammatory bowel disease (IBD). Patients/MethodsmRNA expression in colonic mucosa from patients with UC, Crohns disease (CD) and non-IBD controls was measured by reverse-transcribed real-time polymerase chain reaction (PCR). ResultsEBI3 was significantly increased in both involved and uninvolved colonic mucosa in patients with UC. Although IL-12 p40 was increased in some patients with CD relative to non-IBD controls, the increase was not statistically significant. However, 5-aminosalicylic acid (5-ASA) use was significantly correlated with reduced IL-12 p40 levels in the patients with CD, but not in UC cases. A similar reduction was not seen in 5-ASA-treated UC patients. ConclusionIL-12 p40 expression in CD is heterogeneous. In contrast, expression of the IL-12 p40 homologue, EBI3, is up-regulated in nearly all UC cases and in a subset of CD.

Evidence of T cell receptor β-chain patterns in inflammatory and noninflammatory bowel disease states

T cell activation, as defined by expression of relevant cell surface molecules, such as the interleukin-2 receptor (CD25), is increased in many chronic relapsing diseases, including inflammatory bowel disease (IBD). These T cells are generally activated through contact of their clonotypic T cell receptor (TCR) with a peptide antigen presented by a major histocompatibility complex molecule. One of the putative antigenic contact sites for the TCR is the third complementarity determining region (CDR3) of the TCR β-chain variable region (TCRBV). Therefore, analysis of the TCRBV CDR3 provides insight into the diversity of antigens encountered by a given T cell population. This study evaluated the TCRBV CDR3 usage of the activated intestinal lymphocytes from human subjects with IBD, diverticulitis (inflammatory control), and a normal tissue control. Public patterns, as demonstrated by shared TCRBV CDR3 amino acid sequences of activated intestinal T cell subpopulations, were observed. In particular, a public pattern of TCRBV22, a conserved valine in the fifth position, and use of TCRBJ2S1 or TCRBJ2S5 was present in three of four Crohns disease subjects while not present in the ulcerative colitis subjects. However, the private patterns of TCRBV CDR3 region amino acid sequences were far more striking and easily demonstrated in all individuals studied, including a normal noninflammatory control. Thus we conclude that selective antigenic pressures are prevalent among an individuals activated intestinal lymphocytes.

HUMAN INTESTINAL EPITHELIAL CELL LINES PRODUCE FACTOR(S) THAT INHIBIT CD3-MEDIATED T-LYMPHOCYTE PROLIFERATION

Peripheral blood T lymphocytes (PBT) proliferate more to anti-CD3 stimulation than to anti-CD2 stimulation. On the other hand, fresh, but not cultivated, intestinal intraepithelial lymphocytes (iIEL) exhibit a lower response to CD3 stimulation in comparison to CD2. The goal of this study was to show that the anti-CD3 T-cell response depends on the microenvironment and is independent of the origin of the lymphocytes. Cultured T-cell lines were stimulated with either an anti-CD3 mAb or an anti-CD2 mAb. Either conditioned supernatant from intestinal epithelial cell (IEC) lines or non- conditioned medium (negative control) was added. After 2 days cytokine production and proliferation were measured. Conditioned supernatant decreased the proliferative response of small and large bowel iIEL compared to controls (P = 0.04). In the same experiments, the cytokine production was non-significantly decreased. Immortalized iIEL, that are not regularly stimulated by their CD3 pathway, showed a similar decrease in proliferation (P < 0.001) and cytokine production (P = 0.01) when incubated with conditioned supernatant. Similar results were also obtained with a non-immortalized and an immortalized PBT line (P < 0.001). In a small bowel iIEL cell line, that exhibited a significant response to anti-CD2 stimulation, the proliferative response to anti-CD2 stimulation was preserved. Active conditioned supernatant could be generated from three independent IEC lines and a liver derived epithelial cell line, but not from a non-epithelial control cell line or two extraintestinal epithelial cell lines. We conclude that supernatants of cultured IEC contain soluble factor(s) that cause cultured iIEL and extraintestinal lymphocytes to behave like fresh iIEL. These results, therefore, support and extend the studies of others which suggest that the intestinal microenvironment mucosalizes lymphocytes.

Staphylococcal enterotoxin B induces potent cytotoxic activity by intraepithelial lymphocytes

In food poisoning, Staphylococcus aureus secretes staphylococcal enterotoxin B (SEB), a superantigen that causes intense T‐cell proliferation and cytotoxicity. The effects of SEB on lytic activity by human intestinal intraepithelial lymphocytes (IEL) were investigated. Jejunal IEL, from morbidly obese individuals undergoing gastric bypass operations, were tested for SEB‐induced cytotoxicity against C1R B‐lymphoblastoid cells, HT‐29 adenocarcinoma cells, or CD1d‐transfected cells using the 51Cr‐release assay. Fas and Fas ligand expression were detected by immunofluorescence and flow cytometry and soluble ligand by enzyme‐linked immunosorbent assay (ELISA). In the presence of SEB, IEL became potently cytotoxic against C1R cells and interferon‐γ (IFN‐γ)‐precultured HT‐29 cells, causing 55u2003±u200310% and 31u2003±u20036% lysis, respectively, greater than that by phytohaemagglutinin (PHA)‐, interleukin‐2 (IL‐2)‐, or anti‐T‐cell receptor (TCR)‐activated IEL. SEB‐stimulated peripheral blood (PB) CD8+ T cells lysed similar numbers of C1R cells but fewer HT‐29 cells (53u2003±u200313% and 8u2003±u20035%, respectively). IEL killing of C1R cells involved interaction of major histocompatibility complex (MHC) class II with TCR, CD2 with CD58, and CD11a with CD54, and was perforin mediated. SEB‐induced IEL lysis of HT‐29 cells, in contrast, was caused by an unknown target cell structure, not MHC class II or CD1d, and resulted from a combination of perforin and Fas‐mediated events. The potent cytotoxic activities of IEL promoted by SEB utilize two different mechanisms, depending on the surface receptors expressed by the target cells.

Natriuretic peptides for the prediction of severely impaired peak VO2 in patients with lung disease.

BACKGROUNDnB-type natriuretic peptide (BNP) is a predictor of death in patients with lung disease. We hypothesised that in patients with lung disease, BNP and N-terminal-pro-B-type natriuretic peptide (NT-proBNP) could predict a peak VO(2)<15 ml/kg/min, which is the proposed cut-off indicating an increased risk of perioperative complications during lung resection surgery.nnnMETHODSnBNP and NT-proBNP were measured in 85 patients with a variety of pulmonary pathologies undergoing cardiopulmonary exercise testing and fulfilling criteria for appropriate effort.nnnRESULTSnBNP [69 (42-270) vs. 33 (15-65)pg/ml; p=0.001] and NT-proBNP [290 (129-1075) vs. 65 (21-129)pg/ml; p<0.001] were higher in patients with peak VO(2)<15 ml/kg/min (n=27) as compared to those with peak VO(2)> or =15 ml/kg/min (n=58). Apart from the forced expiratory volume within the first second (FEV(1)), body mass index (BMI), diabetes, and the alveolo-arterial oxygen pressure difference [D(A-a)O(2); only in the BNP model], BNP or NT-proBNP respectively were independent predictors of peak VO(2)<15 ml/kg/min. The areas under the receiver-operator-characteristics curve (AUC) for BNP and NT-proBNP to predict a peak VO(2)<15 ml/kg/min were 0.73 and 0.80 respectively. A five-item (BNP) or four-item (NT-proBNP) score including BMI, FEV(1), diabetes, D(A-a)O(2), and BNP/NT-proBNP had an AUC of 0.87 and 0.88 respectively for the prediction of peak VO(2)<15ml/kg/min.nnnCONCLUSIONSnIn patients with lung disease, BNP or NT-proBNP is independently associated with low peak VO(2). A simple score based on spirometry, blood gases and BNP or NT-proBNP has a high accuracy for the prediction of a peak VO(2)<15 ml/kg/min.

Impact of mannose-binding lectin deficiency on radiocontrast-induced renal dysfunction: a post-hoc analysis of a multicenter randomized controlled trial

BackgroundLocal renal ischemia is regarded as an important factor in the development of contrast-induced nephropathy (CIN). Mannose-binding lectin (MBL) is involved in the tissue damage during experimental ischemia/reperfusion injury of the kidneys. The aim of the present study was to investigate the association of MBL deficiency with radiocontrast-induced renal dysfunction in a large prospective cohort.Methods246 patients with advanced non–dialysis-dependent renal dysfunction who underwent radiographic contrast procedures were included in the study. Baseline serum MBL levels were analyzed according to the occurrence of a creatinine-based (increase of ≥0.5u2009mg/dL or ≥25% within 48u2009hours) or cystatin C-based (increase of ≥10% within 24u2009hours) CIN.ResultsThe incidence of creatinine-based and cystatin C-based CIN was 6.5% and 24%, respectively. MBL levels were not associated with the occurrence of creatinine-based CIN. However, patients that experienced a cystatin C increase of ≥10% showed significantly higher MBL levels than patients with a rise of <10% (median 2885 (IQR 1193–4471) vs. 1997 (IQR 439–3504)ng/mL, p = 0.01). In logistic regression analysis MBL deficiency (MBL levels≤500u2009ng/ml) was identified as an inverse predictor of a cystatin C increase ≥10% (OR 0.34, 95% CI 0.15-0.8, p = 0.01).ConclusionMBL deficiency was associated with a reduced radiocontrast-induced renal dysfunction as reflected by the course of cystatin C. Our findings support a possible role of MBL in the pathogenesis of CIN.