Oswald Wagner

High plasma levels of soluble P-selectin are predictive of venous thromboembolism in cancer patients - results from the Vienna Cancer and Thrombosis Study (CATS)

Cancer patients are at high risk for venous thromboembolism (VTE). Laboratory parameters with a predictive value for VTE could help stratify patients into high- or low-risk groups. The cell adhesion molecule P-selectin was recently identified as risk factor for VTE. To investigate soluble P-selectin (sP-selectin) in cancer patients as risk predictor for VTE, we performed a prospective cohort study of 687 cancer patients and followed them for a median (IQR) of 415 (221-722) days. Main tumor entities were malignancies of the breast (n = 125), lung (n = 86), gastrointestinal tract (n = 130), pancreas (n = 42), kidney (n = 19), prostate (n = 72), and brain (n = 80); 91 had hematologic malignancies; 42 had other tumors. VTE occurred in 44 (6.4%) patients. In multivariable analysis, elevated sP-selectin (cutoff level, 53.1 ng/mL, 75th percentile of study population) was a statistically significant risk factor for VTE after adjustment for age, sex, surgery, chemotherapy, and radiotherapy (hazard ratio = 2.6, 95% confidence interval, 1.4-4.9, P = .003). The cumulative probability of VTE after 6 months was 11.9% in patients with sP-selectin above and 3.7% in those below the 75th percentile (P = .002). High sP-selectin plasma levels independently predict VTE in cancer patients. Measurement of sP-selectin at diagnosis of cancer could help identify patients at increased risk for VTE.

Drosophila Genome-wide Obesity Screen Reveals Hedgehog as a Determinant of Brown versus White Adipose Cell Fate

Over 1 billion people are estimated to be overweight, placing them at risk for diabetes, cardiovascular disease, and cancer. We performed a systems-level genetic dissection of adiposity regulation using genome-wide RNAi screening in adult Drosophila. As a follow-up, the resulting approximately 500 candidate obesity genes were functionally classified using muscle-, oenocyte-, fat-body-, and neuronal-specific knockdown in vivo and revealed hedgehog signaling as the top-scoring fat-body-specific pathway. To extrapolate these findings into mammals, we generated fat-specific hedgehog-activation mutant mice. Intriguingly, these mice displayed near total loss of white, but not brown, fat compartments. Mechanistically, activation of hedgehog signaling irreversibly blocked differentiation of white adipocytes through direct, coordinate modulation of early adipogenic factors. These findings identify a role for hedgehog signaling in white/brown adipocyte determination and link in vivo RNAi-based scanning of the Drosophila genome to regulation of adipocyte cell fate in mammals.

D-Dimer and Prothrombin Fragment 1 + 2 Predict Venous Thromboembolism in Patients With Cancer: Results From the Vienna Cancer and Thrombosis Study

PURPOSE Venous thromboembolism (VTE) is a well-recognized complication of cancer. Laboratory parameters might be useful to assess the VTE risk in patients with cancer. The aim of this study was to investigate D-dimer and prothrombin fragment 1 + 2 (F 1 + 2), which reflect activation of blood coagulation and fibrinolysis, for prediction of cancer-associated VTE. PATIENTS AND METHODS In a prospective, observational, cohort study of 821 patients with newly diagnosed cancer or progression of disease who did not recently receive chemotherapy, radiotherapy, or surgery were enrolled and followed for a median of 501 days (interquartile range, 255 to 731 days). The malignancies in these patients were as follows: breast (n = 132), lung (n = 119), stomach (n = 35), lower gastrointestinal tract (n = 106), pancreas (n = 46), kidney (n = 22), and prostate (n = 101) cancers; high-grade glioma (n = 102); malignant lymphoma (n = 94); multiple myeloma (n = 17); and other tumor types (n = 47). The study end point was occurrence of objectively confirmed symptomatic or fatal VTE. RESULTS VTE occurred in 62 patients (7.6%). The cutoff level for elevated D-dimer and elevated F 1 + 2 was set at the 75th percentile of the total study population. In multivariable analysis that included elevated D-dimer, elevated F 1 + 2, age, sex, surgery, chemotherapy, and radiotherapy, the hazard ratios (HRs) of VTE in patients with elevated D-dimer (HR, 1.8; 95% CI, 1.0 to 3.2; P = .048) and elevated F 1 + 2 (HR, 2.0; 95% CI, 1.2 to 3.6; P = .015) were statistically significantly increased. The cumulative probability of developing VTE after 6 months was highest in patients with both elevated D-dimer and elevated F 1 + 2 (15.2%) compared with patients with nonelevated D-dimer and nonelevated F 1 + 2 (5.0%; P < .001). CONCLUSION High D-dimer and F 1 + 2 levels independently predict occurrence of VTE in patients with cancer.

The sedoheptulose kinase CARKL directs macrophage polarization through control of glucose metabolism.

Summary Immune cells are somewhat unique in that activation responses can alter quantitative phenotypes upwards of 100,000-fold. To date little is known about the metabolic adaptations necessary to mount such dramatic phenotypic shifts. Screening for novel regulators of macrophage activation, we found nonprotein kinases of glucose metabolism among the most enriched classes of candidate immune modulators. We find that one of these, the carbohydrate kinase-like protein CARKL, is rapidly downregulated in vitro and in vivo upon LPS stimulation in both mice and humans. Interestingly, CARKL catalyzes an orphan reaction in the pentose phosphate pathway, refocusing cellular metabolism to a high-redox state upon physiological or artificial downregulation. We find that CARKL-dependent metabolic reprogramming is required for proper M1- and M2-like macrophage polarization and uncover a rate-limiting requirement for appropriate glucose flux in macrophage polarization.

Effect of endothelin-1 in man.

The effect of an intravenous infusion of human endothelin-1 on blood pressure and plasma concentrations of endothelin-1, potassium, sodium, renin, aldosterone, and atrial natriuretic factor was investigated in six healthy, sodium-loaded men. During the peptides exogenous application (1.0, 2.5, and 5.0 ng/kg.min), its plasma concentrations rose from a basal value of 1.2 +/- 0.3 to 3.2 +/- 1.9, 9.9 +/- 7.6, and 56.5 +/- 50.3 pmol/l (p less than 0.01), respectively, and mean blood pressure rose from a basal value of 87.1 +/- 7.3 to 92.6 +/- 8.2 mm Hg (p less than 0.01). A rise in serum concentrations of potassium (from 4.0 +/- 0.3 to 4.6 +/- 0.2 mmol/l; p less than 0.005) and a concomitant fall in serum concentrations of sodium (from 142.7 +/- 1.0 to 139.5 +/- 2.3 mmol/l; p less than 0.05) was seen in each subject. Plasma concentrations of renin, aldosterone, and atrial natriuretic factor did not change during the infusion of endothelin-1. Thus, in the doses used, endothelin-1 induces a rise in blood pressure and serum potassium concentrations.

Leptin Induces Endothelin-1 in Endothelial Cells In Vitro

Leptin, a protein encoded by the obese gene, is produced by adipocytes and released into the bloodstream. In obese humans, serum leptin levels are increased and correlate with the individual’s body mass index and blood pressure. Elevated serum concentrations of endothelin-1 (ET-1), a potent vasoconstrictor and mitogen, were also observed in obese subjects. The pathomechanisms underlying this ET-1 increase in obesity are poorly understood. In the present study, we investigated the influence of the ob gene product leptin on the expression of ET-1 in human umbilical vein endothelial cells (HUVECs). Binding studies using 125I-radiolabeled leptin revealed high- and low-affinity leptin binding sites on HUVECs (Kd1=13.1±3.1 nmol/L and Kd2=1390±198 nmol/L, respectively), mediating a time- and dose-dependent increase of ET-1 mRNA expression and protein secretion after incubation of HUVECs with leptin. This leptin-induced ET-1 expression was inhibited by preincubation of HUVECs with 0.75 &mgr;mol/L antisense phosphorothioate oligonucleotides directed against the leptin receptor Ob-Rb. Furthermore, after incubation with leptin, increased nuclear staining of c-fos and c-jun, the major components of the transcription factor AP-1, and increased AP-1 DNA binding were observed. Transient transfection studies with ET-1 promoter constructs showed that leptin-induced promoter activity was abolished in the absence of AP-1 binding sites or by cotransfection with a plasmid overexpressing a mutated jun, which is able to bind c-fos but not DNA. Thus, leptin upregulates ET-1 production in HUVECs via a mechanism potentially involving jun binding members of the bZIP family.

Overweight, Obesity, and the Risk of Recurrent Venous Thromboembolism

BACKGROUND Excess body weight is a risk factor for a first venous thromboembolism. The impact of excess body weight on risk of recurrent venous thrombosis is uncertain. METHODS We studied 1107 patients for an average of 46 months after a first unprovoked venous thromboembolism and withdrawal of anticoagulant therapy. Excluded were pregnant patients, those requiring long-term antithrombotic treatment, and those who had a previous or secondary thrombosis, natural coagulation inhibitor deficiency, lupus anticoagulant, or cancer. Our study end point was symptomatic recurrent venous thromboembolism. RESULTS A total of 168 patients had recurrent venous thromboembolism. Mean (SD) body mass index (BMI) (calculated as weight in kilograms divided by height in meters squared) was significantly higher among patients with recurrence than among those without recurrence: 28.5 (6.0) vs 26.9 (5.0) (P = .01). The relationship between excess body weight and recurrence was linear; the adjusted hazard ratio for each 1-point increase in BMI was 1.044 (95% confidence interval [CI], 1.013-1.076) (P < .001). Four years after discontinuation of anticoagulant therapy, the probability of recurrence was 9.3% (95% CI, 6.0%-12.7%) among patients of normal weight and 16.7% (95% CI, 11.0%-22.3%) and 17.5% (95% CI, 13.0%-22.0%) among overweight and obese patients, respectively. Compared with patients of normal weight, the hazard ratio of recurrence adjusted for age, sex, factor V Leiden, prothrombin G20210A mutation, high factor VIII levels, and type of initial venous thromboembolic event was 1.3 (95% CI, 0.9-1.9) (P = .20) among overweight patients and 1.6 (95% CI, 1.1-2.4) (P = .02) among obese individuals. The population attributable risk corresponding to excess body weight was 26.8% (95% CI, 5.3%-48.2%). CONCLUSION Excess body weight is a risk factor of recurrent venous thromboembolism.

A Proinflammatory State Is Detectable in Obese Children and Is Accompanied by Functional and Morphological Vascular Changes

Background—Obesity is generally accepted as a risk factor for premature atherosclerosis. Subclinical inflammation as quantified by blood levels of C-reactive protein (CRP) contributes to the development and progression of atherosclerosis. We hypothesized that inflammation in obese children is related to functional and early morphological vascular changes. Methods and Results—Blood levels of high sensitivity (hs) CRP, hsIL-6, the soluble intercellular adhesion molecule1 (ICAM-1), vascular cell adhesion molecule (VCAM)-1, and E-selectin were measured in 145 severely obese (body mass index [BMI], 32.2±5.8 kg/m2) and 54 lean (BMI, 18.9±3.2 kg/m2) children 12±4 years old. Flow-mediated dilation (FMD) of the brachial artery and carotid intima-media thickness (IMT) measured by high-resolution ultrasound as markers of early vascular changes were assessed in 92 (77 obese and 15 lean) and 59 (50 obese and 9 lean) children, respectively. Obese children had significantly higher levels of hsCRP, hsIL-6, and E-selectin than healthy controls (4.1±4.8 versus 0.9±1.5 mg/L, P<0.001 for hsCRP; 1.99±1.30 versus 1.42±1.01 pg/mL, P=0.05 for hsIL-6; and 78±38 versus 59±29 ng/mL, P=0.01 for E-selectin). There were no differences in the levels of ICAM-1 and VCAM-1 between groups. Obese children had lower peak FMD response (7.70±6.14 versus 11.06±3.07%, P=0.006) and increased IMT (0.37±0.04 versus 0.34±0.03 mm, P=0.03) compared with controls. Morbidly obese children (n=14, BMI 44.1±3.9 kg/m2) had highest levels of hsCRP (8.7±0.7 mg/L), hsIL-6 (3.32±1.1 pg/mL), and E-selectin (83±40 ng/mL). Conclusions—A proinflammatory state is detectable in obese children, which is accompanied by impaired vascular endothelial function and early structural changes of arteries, even in young subjects at risk. It remains to be determined whether high hsCRP in obese children predicts cardiovascular events.

Heme oxygenase and carbon monoxide initiate homeostatic signaling

Carbon monoxide (CO), a gaseous second messenger, arises in biological systems during the oxidative catabolism of heme by the heme oxygenase (HO) enzymes. Many biological functions of HO, such as regulation of vessel tone, smooth muscle cell proliferation, neurotransmission, and platelet aggregation, and anti-inflammatory and antiapoptotic effects have been attributed to its enzymatic product, CO. How can such diverse actions be achieved by a simple diatomic gas; can its protective effects be explained via regulation of a common signaling pathway? A number of the known signaling effects of CO depend on stimulation of soluble guanylate cyclase and/or activation of mitogen-activated protein kinases. The consequences of this activation remain unknown but appear to differ depending on cell type and circumstances. The majority of studies reporting a protective role of CO focus on pathways initiated by the pathological stimulus (e.g., lipopolysaccharide, hypoxia, balloon injury, tumor necrosis factor α, etc.) and its consequential modulation by CO. What has been less studied is the manner in which CO exposure alone modulates the molecular machinery of the cell so that a subsequent stress stimulus will elicit a homeostatic response as opposed to one that is chaotic and disordered. CO potentially interacts with other intracellular hemoprotein targets, although little is known about the functional significance of such interactions other then the known targets including mitochondrial oxidases, oxygen sensors, and nitric oxide synthases. The earliest response of a cell exposed to low concentrations of CO is clearly an increase in reactive oxygen species formation that we define as oxidative conditioning. This has important consequences for inflammation, proliferation, mitochondria biogenesis, and apoptosis. Within this review, we will highlight recent research on the molecular events underlying the physiologic effects of CO—which lead to cytoprotective conditioning.

Inflammation and Carotid Artery—Risk for Atherosclerosis Study (ICARAS)

Background—Compelling evidence suggests that inflammation is fundamentally involved in the pathogenesis of atherosclerosis; however, temporal correlation between inflammation and morphological features of atherosclerosis progression has not been demonstrated unequivocally. Methods and Results—We prospectively studied 1268 consecutive patients who were initially asymptomatic with respect to carotid artery disease. Patients underwent serial carotid ultrasound investigations at baseline and after a follow-up interval of a median of 7.5 months (range 6 to 9 months), with measurement of carotid flow velocities and categorization of carotid arteries as 0% to 29%, 30% to 49%, 50% to 69%, 70% to 89%, or 90% to 99% stenosed or occluded. High-sensitivity C-reactive protein (hs-CRP) and serum amyloid A (SAA) were measured at baseline and follow-up. Progression of carotid atherosclerosis was found in 103 (8.1%) of 1268 patients. Hs-CRP and SAA, respectively, at baseline (P=0.004 and P=0.014) and follow-up (P<0.001 and P<0.001) and the change from baseline to follow-up (P<0.001 and P<0.001) were significantly associated with progressive atherosclerosis. Adjusted ORs (95% CI) for atherosclerosis progression with increasing quintiles of baseline hs-CRP were 1.65 (0.71 to 3.84), 1.87 (0.8 to 4.37), 3.32 (1.49 to 7.39), and 3.65 (1.65 to 8.08), and with increasing quintiles of baseline SAA, they were 0.86 (0.38 to 1.92), 0.99 (0.49 to 1.99), 1.72 (0.91 to 3.28), and 2.28 (1.24 to 4.20), respectively, compared with the lowest quintiles. Conclusions—These findings supply evidence for a close temporal correlation between inflammation and morphological features of rapidly progressive carotid atherosclerosis, which suggests that elevation or increase of the inflammatory biomarkers hs-CRP and SAA identifies the presence of active atherosclerotic disease.