Previous studies demonstrated that the CXC chemokine, MGSA/GRO-alpha and its receptor, CXCR2, are expressed during wound healing by keratinocytes and endothelial cells at areas where epithelialization and neovascularization occur. The process of wound healing is dependent on leukocyte recruitment, keratinocyte proliferation and migration, and angiogenesis. These processes may be mediated in part by CXC chemokines, such as interleukin-8 and MGSA/GRO-alpha. To examine further the significance of CXC chemokines in wound healing, full excisional wounds were created on CXCR2 wild-type (+/+), heterozygous (+/-), or knockout (-/-) mice. Wounds were histologically analyzed for neutrophil and monocyte infiltration, neovascularization and epithelialization at days 3, 5, 7, and 10 postwounding. The CXCR2 -/- mice exhibited defective neutrophil recruitment, an altered temporal pattern of monocyte recruitment, and altered secretion of interleukin-1beta. Significant delays in wound healing parameters, including epithelialization and decreased neovascularization, were also observed in CXCR2 -/- mice. In vitro wounding experiments with cultures of keratinocytes established from -/- and +/+ mice revealed a retardation in wound closure in CXCR2 -/- keratinocytes, suggesting a role for this receptor on keratinocytes in epithelial resurfacing that is independent of neutrophil recruitment. These in vitro and in vivo studies further establish a pathophysiologic role for CXCR2 during cutaneous wound repair.

A single dose of raxibacumab improved survival in rabbits and monkeys with symptomatic inhalational anthrax. (ClinicalTrials.gov number, NCT00639678.)

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Tumor necrosis factor-alpha (TNF) and interleukin-1beta (IL-1) are cytokines that induce expression of various genes through activation of the redox-sensitive transcription factor nuclear factor-kappaB (NF-kappaB). We have previously cloned the entire human MnSOD (SOD2) gene and found several NF-kappaB-binding sites in the 5' and 3' flanking and intronic regions. To test whether these putative NF-kappaB-binding sites are able to respond to TNF and IL-1, we performed induction analysis using various deletion constructs ligated to a luciferase reporter gene. We found that the 5' and 3' flanking regions containing several NF-kappaB-binding sites do not mediate MnSOD induction by TNF or IL-1. When a 342-bp intron 2 fragment containing NF-kappaB, C/EBP, and NF-1 binding sites was linked to the basal promoter of the SOD2 gene, transcriptional activities were significantly increased in response to TNF and IL-1 in an orientation- and position-independent manner. To accurately identify the element that is most critical for the enhancer activity, deletions and specific mutations of each individual site were studied. The results indicated that the NF-kappaB binding site is essential but not sufficient for TNF- or IL-1-mediated induction. Furthermore, NF-kappaB elements in the 5' and 3' flanking regions could be made to function in TNF or IL-1 induction when they were transposed to the intronic fragment. Taken together, these results suggest that an NF-kappaB element and its location in the SOD2 gene is critical for TNF/IL-1-mediated induction. However, a complex interaction between NF-kappaB and other transcription elements is needed for a high-level induction.

Aims Inflammation is a central process in the pathophysiology of heart failure (HF), but trials targeting tumour necrosis factor (TNF)‐α were largely unsuccessful. Interleukin (IL)‐6 is an important inflammatory mediator and might constitute a potential pharmacologic target in HF. However, little is known regarding the association between IL‐6 and clinical characteristics, outcomes and other inflammatory biomarkers in HF. We thus aimed to identify and characterize these associations. Methods and results Interleukin‐6 was measured in 2329 patients [89.4% with a left ventricular ejection fraction (LVEF) ≤ 40%] of the BIOSTAT‐CHF cohort. The primary outcome was all‐cause mortality and HF hospitalization during 2 years, with all‐cause, cardiovascular (CV), and non‐CV death as secondary outcomes. Approximately half (56%) of all included patients had plasma IL‐6 values greater than the previously determined 95th percentile of normal values at baseline. Elevated N‐terminal pro‐brain natriuretic peptide, procalcitonin and hepcidin, younger age, TNF‐α/IL‐1‐related biomarkers, or having iron deficiency, atrial fibrillation and LVEF > 40% independently predicted elevated IL‐6 levels. IL‐6 independently predicted the primary outcome [HR (95% confidence interval) per doubling: 1.16 (1.11–1.21), P < 0.001], all‐cause mortality [1.22 (1.16–1.29), P < 0.001] and CV as well as non‐CV mortality [1.16 (1.09–1.24), P < 0.001; 1.31 (1.18–1.45), P < 0.001], but did not improve discrimination in previously published risk models. Conclusions In a large, heterogeneous cohort of HF patients, elevated IL‐6 levels were found in more than 50% of patients and were associated with iron deficiency, reduced LVEF, atrial fibrillation and poorer clinical outcomes. These findings warrant further investigation of IL‐6 as a potential therapeutic target in specific HF subpopulations.