Interleukin-6 limits influenza-induced inflammation and protects against fatal lung pathology

Balancing the generation of immune responses capable of controlling virus replication with those causing immunopathology is critical for the survival of the host and resolution of influenza-induced inflammation. Based on the capacity of interleukin-6 (IL-6) to govern both optimal T-cell responses and inflammatory resolution, we hypothesised that IL-6 plays an important role in maintaining this balance. Comparison of innate and adaptive immune responses in influenza-infected wild-type control and IL-6-deficient mice revealed striking differences in virus clearance, lung immunopathology and generation of heterosubtypic immunity. Mice lacking IL-6 displayed a profound defect in their ability to mount an anti-viral T-cell response. Failure to adequately control virus was further associated with an enhanced infiltration of inflammatory monocytes into the lung and an elevated production of the pro-inflammatory cytokines, IFN-α and TNF-α. These events were associated with severe lung damage, characterised by profound vascular leakage and death. Our data highlight an essential role for IL-6 in orchestrating anti-viral immunity through an ability to limit inflammation, promote protective adaptive immune responses and prevent fatal immunopathology

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

Correction to: Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

The original version of this article unfortunately contained a mistake

Interleukin-6 in renal disease and therapy

Interleukin (IL)-6 has become a major target for clinical intervention in various autoimmune conditions. Here, drugs including the humanized anti-IL-6 receptor (IL-6R) antibody tocilizumab emphasize the clinical importance of IL-6 in driving disease and poor patient outcomes. During the course of this review, we will outline the biology surrounding IL-6 and discuss the impact of IL-6 in renal disease and the clinical complications associated with renal replacement therapies and transplantation. We will also consider the merit of IL-6 measurement as a prognostic indicator and provide a clinical perspective on IL-6-blocking therapies in renal disease

Interleukin-1 beta regulates proximal tubular cell transforming growth factor beta-1 signalling

Background. Increased transforming growth factor beta-1 (TGF beta) expression in the kidney is central not only to the pathogenesis of tubulointerstitial fibrosis but also in repair following acute injury. Recent work suggests that pro-inflammatory cytokines may determine epithelial cell responses to TGF beta in the contexts of acute injury and chronic wounding. Methods. In this study, we examined the effects of interleukin-1 beta (IL-1) on proximal tubular cell (PTC) response to TGF beta. Results. IL-1 induced the rapid activation of NF-κB in PTC. This was associated with inhibition of Smad2 and Smad3 signalling. NF-κB activation by IL-1 was transient, with a change from p65/p50 heterodimer to p50/p50 homodimer formation by 24 h and a switch to enhanced Smad signalling response to TGF beta. This was associated with IL-6 generation and prevented by IL-6 receptor blockade. Conclusion. In summary, IL-1 has a biphasic effect on PTC TGF beta signalling, with early NF-κB-mediated inhibition and delayed sensitization via an autocrine IL-6 loop. These results provide mechanistic insight into how acute and chronic inflammation help define epithelial cell response to TGF beta, and hence how TGF beta can have apparently contradictory roles, being involved in controlled healing following acute injury on one hand, yet the principal promoter of scarring in chronic disease on the other

ERK is integral to the IFN-γ-mediated activation of STAT1, the expression of key genes implicated in atherosclerosis, and the uptake of modified lipoproteins by human macrophages

The proinflammatory cytokine IFN-γ is a master regulator of atherosclerosis and mediates its cellular actions mainly through STAT1. Unfortunately, the impact of other IFN-γ inducible pathways on STAT1 activation and the regulation of downstream responses associated with atherosclerosis in human macrophages are poorly understood and were therefore investigated. In this study, we demonstrate that the IFN-γ–mediated phosphorylation of STAT1 on Ser727, crucial for its maximal activity, was attenuated in human macrophages by pharmacological inhibition of ERK. In these cells, IFN-γ induced changes in the expression of several key genes implicated in atherosclerosis, such as MCP-1, through an ERK-dependent mechanism. Additionally, the IFN-γ–induced activity of STAT1-responsive promoters was attenuated by transfection of dominant-negative forms of ERK and other key components of this pathway. Furthermore, the IFN-γ–induced uptake of acetylated and oxidized low-density lipoprotein by human macrophages was attenuated by pharmacological inhibition or RNA interference–mediated knockdown of ERK. These studies suggest a critical role for ERK signaling in the IFN-γ–mediated changes in macrophage cholesterol homeostasis and gene expression during atherosclerosis

Classic interleukin-6 receptor signaling and interleukin-6 trans-signaling differentially control angiotensin II-dependent hypertension, cardiac signal transducer and activator of transcription-3 activation, and vascular hypertrophy in vivo

Interleukin (IL)-6 acts via a receptor complex consisting of the cognate IL-6 receptor (IL-6R) or the soluble IL-6 receptor (sIL-6R) and glycoprotein 130 (gp130). Here, we investigated the role of these IL-6R components in hypertension and vascular hypertrophy in mice. Angiotensin (Ang) II (1.1 mg/kg/day) caused hypertension and cardiac/aortic hypertrophy in wild-type, but not IL-6(-/-), mice throughout 7 days. A recombinant dimeric soluble gp130 (sgp130Fc; 50 to 100 microg, i.p.) blocked Ang II hypertension but not hypertrophy in wild-type mice. Cognate IL-6R was detected in aortic smooth muscle, but its levels and those of plasma sIL-6R were approximately 50% decreased in IL-6(-/-) mice. Ang II infusion activated signal transducer and activator of transcription-3 in heart of WT and decreased Ang II receptor 1 (ATR1) expression in aorta. Both responses were unaffected by sgp130Fc and absent in IL-6(-/-) mice. In summary, we show that IL-6 trans-signaling is required for Ang II-dependent hypertension, but that hypertrophy, down-regulation of AT1R, and cardiac signal transducer and activator of transcription-3 activation are mediated via cognate IL-6R. These data show that IL-6 responses in a single disease context are governed by both modes of IL-6 signaling, with each pathway eliciting different outcomes. Inhibition of IL-6 signaling is suggested as a potential therapy for hypertension and cardiac hypertrophy