Hypoxia-inducible Factor and Target Gene Expression Are Decreased in Patients with Sepsis

Abstract

Background: Hypoxia-inducible factor-1 (HIF-1) is a molecular key player in response to hypoxemic/inflammatory conditions prevailing in sepsis. In a prospective observational study, we tested the hypotheses that sepsis affects HIF-1α messenger ribonucleic acid (mRNA) expression (primary hypothesis) and also (secondary hypotheses) the expression of the HIF-1α target genes adrenomedullin and β 2 -integrins. Furthermore, we tested that lipopolysaccharide administration increases HIF-1α mRNA and protein in naive and endotoxin-tolerant monocytes. Methods: In 99 patients with sepsis and 48 healthy volunteers, leukocyte HIF-1α mRNA expression (real-time polymerase chain reaction), cytokine concentrations (enzymelinked immunosorbent assay), and intracellular distribution of HIF-1α protein (immunofluorescence staining) were assessed. In vitro, HIF-1α mRNA expression and protein were measured in naive or endotoxin-tolerant (48 h; 0.05 ng/ml lipopolysaccharide) monocytes, with/without additional lipopolysaccharide (6 h; 1 μg/ml). Results: In comparison to healthy volunteers, HIF-1α mRNA expression (−67%; P = 0.0001) and HIF-1α protein positive cells (−66.7%; P = 0.01) were decreased in sepsis. mRNA expression of adrenomedullin (−75%), CD11a (−85%), and CD11b (−86%; all P = 0.0001) was also decreased. In contrast, interleukin 6 (P = 0.0001), interleukin 10 (P = 0.0001), and tumor necrosis factor-α (P = 0.0002) concentrations were increased. Of note, HIF-1α mRNA expression was inversely associated with illness severity (Simplified Acute Physiology Score II; r = −0.29; P = 0.0001). In vitro, acute lipopolysaccharide administration of naive monocytic cells increased HIF-1α mRNA expression, whereas HIF-1α mRNA and protein (−60%; P = 0.001) were decreased in endotoxin-tolerant cells, which still up regulated cytokines. Conclusions: In sepsis, HIF-1α mRNA expression was suppressed and inversely associated with illness severity. Hypoxia-inducible Factor and Target Gene Expression What We Already Know about This Topic• Sepsis is a leading cause of perioperative morbidity and mortality • Hypoxia-inducible factor-1α is a marker of cellular hypoxia What This Article Tells Us That Is New• In monocytes of patients with sepsis, hypoxia-inducible factor-1α was decreased compared to monocytes of healthy control patients, and the decrease in expression was inversely related to the severity of sepsis • Disease severity may be linked to an impaired response to hypoxia ◇

Hydrocortisone Fails to Abolish NF-κB1 Protein Nuclear Translocation in Deletion Allele Carriers of the NFKB1 Promoter Polymorphism (-94ins/delATTG) and Is Associated with Increased 30-Day Mortality in Septic Shock

“…The sample size of 160 patients with septic shock is rather small and our results require independent replication in larger cohorts. However, consenting patients with septic shock patients are hard to enroll given that only about 2-20% of all intensive care unit patients suffer from severe sepsis including septic shock [1], [12], [18], [29], [30].…”

“…Immunofluorescence staining was performed using a primary NF-κB1 rabbit anti-human polyclonal p65 antibody (1∶200 dilution, Santa Cruz Biotechnologies, Santa Cruz, CA) followed by a Immunoglobulin G - Alexa-flour 568 coupled goat anti-rabbit antibody (1∶400 dilution, Molecular Probes, Eugene, OR), as described previously [12], [18], [19].…”

“…A Nikon Eclipse E1000 fluorescence microscopy (Nikon GmbH, Düsseldorf, Germany) with NIS-Elements F.30.0 imaging software (Laboratory Imaging, Prague, Czech Republic) was used. Slides were analyzed in a standardized order, and representative images of each quadrant were captured at 20-fold magnification and nuclear NF-κB1 positive cells were counted using an image software (ImageJ, National Institute of Health, Bethesda, MD) [12], [18].…”

“…Patients were treated with a multimodal concept which included protective mechanical ventilation, hemodynamic, antibiotic, and diagnostic management, as published previously [3], [12], [18]. Continuous hemofiltration/dialysis was technically performed by the Department of Nephrology according to standardized protocols.…”

“…A post-hoc two-tailed Student's t-test for independent samples was performed applying a Bonferroni correction for multiple tests. Analyses were performed using the Graphpad Prism 5 software (San Diego, CA) [12], [18].…”