Pathophysiology of acute respiratory distress syndrome. Glucocorticoid receptor-mediated regulation of inflammation and response to prolonged glucocorticoid treatment

The Treatment of Tubal Inflammatory Infertility using Yinjia Tablets through EGFR/MEK/ERK Signaling Pathway based on Network Pharmacology

Background: Salpingitis obstructive infertility (SOI) refers to infertility caused by abnormal conditions such as tubal adhesion and blockage caused by acute and chronic salpingitis. SOI has a serious impact on women's physical and mental health and family harmony, and it is a clinical problem that needs to be solved urgently.

Objective: The purpose of the present study was to explore the potential pharmacological mechanisms of the Yinjia tablets (Yin Jia Pian, YJP) on tubal inflammation.

Methods: Networks of YJP-associated targets and tubal inflammation-related genes were constructed through the STRING database. Potential targets and pathway enrichment analysis related to the therapeutic efficacy of YJP were identified using Cytoscape and Database for Annotation, Visualization, and Integrated Discovery (metascape). E. coli was used to establish a rat model of tubal inflammation and to validate the predictions of network pharmacology and the therapeutic efficacy of YJP. H&E staining was used to observe the pathological changes in fallopian tubes. TEM observation of the ultrastructure of the fallopian tubes. ELISA was used to detect the changes of IL-6 and TNF-α in fallopian tubes. Immunohistochemistry was used to detect the expression of ESR1. The changes of Bcl-2, ERK1/2, p-ERK1/2, MEK, p-MEK, EGFR, and p-EGFR were detected by western blot.

Results: Through database analysis, it was found that YJP shared 105 identical targets with the disease. Network pharmacology analysis showed that IL-6, TNF, and EGFR belong to the top 5 core proteins associated with salpingitis, and EGFR/MEK/ERK may be the main pathway involved. The E. coli-induced disease rat model of fallopian tube tissue showed damage, mitochondrial disruption, and increased levels of the inflammatory factors IL-6 and TNF-α. Tubal inflammatory infertility rats have increased expression of Bcl-2, p-ERK1/2, p-MEK, and p-EGFR, and decreased expression of ESR1. In vivo, experiments showed that YJP improved damage of tissue, inhibited shedding of tubal cilia, and suppressed the inflammatory response of the body. Furthermore, YJP inhibited EGFR/MEK/ERK signaling, inhibited the apoptotic protein Bcl-2, and upregulated ESR1.

Conclusion: This study revealed that YJP Reducing tubal inflammation and promoting tissue repair may be associated with inhibition of the EGFR/MEK/ERK signaling pathway.

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Glucocorticoid Treatment in Acute Respiratory Distress Syndrome: An Overview on Mechanistic Insights and Clinical Benefit

Acute lung injury/acute respiratory distress syndrome (ALI/ARDS), triggered by various pathogenic factors inside and outside the lungs, leads to diffuse lung injury and can result in respiratory failure and death, which are typical clinical critical emergencies. Severe acute pancreatitis (SAP), which has a poor clinical prognosis, is one of the most common diseases that induces ARDS. When SAP causes the body to produce a storm of inflammatory factors and even causes sepsis, clinicians will face a two-way choice between anti-inflammatory and anti-infection objectives while considering the damaged intestinal barrier and respiratory failure, which undoubtedly increases the difficulty of the diagnosis and treatment of SAP-ALI/ARDS. For a long time, many studies have been devoted to applying glucocorticoids (GCs) to control the inflammatory response and prevent and treat sepsis and ALI/ARDS. However, the specific mechanism is not precise, the clinical efficacy is uneven, and the corresponding side effects are endless. This review discusses the mechanism of action, current clinical application status, effectiveness assessment, and side effects of GCs in the treatment of ALI/ARDS (especially the subtype caused by SAP).

Methylprednisolone pulse therapy for critically ill patients with COVID-19: a cohort study

BACKGROUND

The guidelines recommend the use of dexamethasone 6 mg or an equivalent dose in patients with coronavirus disease 2019 (COVID-19) who require supplemental oxygen. Given that the severity of COVID-19 varies, we investigated the effect of a pulse dose of corticosteroids on the clinical course of critically ill patients with COVID-19.

METHODS

This single-center, retrospective cohort study was conducted between September and December 2021, which was when the Delta variant of the COVID-19 virus was predominant. We evaluated the mortality and oxygenation of severe to critical COVID-19 cases between groups that received dexamethasone 6 mg for 10 days (control group) and methylprednisolone 250 mg/day for 3 days (pulse group).

RESULTS

Among 44 patients, 14 and 30 patients were treated with control steroids and pulse steroids, respectively. There was no difference in disease severity, time from COVID-19 diagnosis to steroid administration, or use of remdesivir or antibacterial agents between the two groups. The pulse steroid group showed a significant improvement in oxygenation before and after steroid treatment (P<0.001) compared with the control steroid group (P=0.196). There was no difference in in-hospital mortality (P=0.186); however, the pulse steroid group had a lower mortality rate (23.3%) than the control steroid group (42.9%). There was a significant difference in the length of hospital stay between both two groups (P=0.039).

CONCLUSIONS

Pulse steroids showed no mortality benefit but were associated with oxygenation improvement and shorter hospital stay than control steroids. Hyperglycemia should be carefully monitored with pulse steroids.

The Effect of a Combined Ganciclovir, Methylprednisolone, and Immunoglobulin Regimen on Survival and Functional Outcomes in Patients With Japanese Encephalitis

Objective: There is currently no effective treatment for Japanese encephalitis, which has a high rate of morbidity and mortality. This study assessed the effectiveness of a ganciclovir, methylprednisolone, and immunoglobulin combination (TAGMIC) therapy in decreasing cognitive impairment and mortality among patients with Japanese encephalitis.

Methods: We retrospectively assessed the clinical data of 31 patients diagnosed with Japanese encephalitis, who were admitted to an intensive care unit. Patients were divided into the TAGMIC and non-TAGMIC group according to their treatment regime. We compared the 60-day, 6-month, and overall mortality and survival curves between groups. We also compared Barthel Index scores, Montreal Cognitive Assessment (MoCA) scores, and diffusion tensor imaging (DTI) results.

Results: There was no significant difference in the 30-day mortality rate or Kaplan–Meier survival curve between groups. The 60-day, 6-month, and overall mortality rates in the TAGMIC group were significantly reduced (P = 0.043, P = 0.018, and P = 0.018, respectively) compared with the non-TAGMIC group (0, 0, 0 vs. 31.25, 37.5, 37.5%, respectively). The 60-day, 6-month, and overall Kaplan–Meier survival curves were significantly different between groups (P = 0.020, P = 0.009, P = 0.009, respectively). There was no significant difference in the Barthel Index scores of surviving patients. Among the five patients who underwent MoCA and DTI, four had a score of 0/5 for delayed recall (no cue), while the remaining patient had a score of 2/5. All five patients were able to achieve a score of 5/5 with classification and multiple-choice prompts, and had sparse or broken corpus callosum (or other) fibre bundles.

Conclusion: TAGMIC treatment can reduce mortality due to severe Japanese encephalitis. The memory loss of surviving patients is mainly due to a disorder of the memory retrieval process, which may be related to the breakage of related fibre bundles.

Preventing the development of severe COVID-19 by modifying immunothrombosis

BACKGROUND

COVID-19-associated acute respiratory distress syndrome (ARDS) is associated with significant morbidity and high levels of mortality. This paper describes the processes involved in the pathophysiology of COVID-19 from the initial infection and subsequent destruction of type II alveolar epithelial cells by SARS-CoV-2 and culminating in the development of ARDS.

MAIN BODY

The activation of alveolar cells and alveolar macrophages leads to the release of large quantities of proinflammatory cytokines and chemokines and their translocation into the pulmonary vasculature. The presence of these inflammatory mediators in the vascular compartment leads to the activation of vascular endothelial cells platelets and neutrophils and the subsequent formation of platelet neutrophil complexes. These complexes in concert with activated endothelial cells interact to create a state of immunothrombosis. The consequence of immunothrombosis include hypercoagulation, accelerating inflammation, fibrin deposition, migration of neutrophil extracellular traps (NETs) producing neutrophils into the alveolar apace, activation of the NLRP3 inflammazome, increased alveolar macrophage destruction and massive tissue damage by pyroptosis and necroptosis Therapeutic combinations aimed at ameliorating immunothrombosis and preventing the development of severe COVID-19 are discussed in detail.

Mortality in COVID-19 patients with acute respiratory distress syndrome and corticosteroids use: a systematic review and meta-analysis

OBJECTIVES

The acute respiratory distress syndrome (ARDS) secondary to viral pneumonitis is one of the main causes of high mortality in patients with COVID-19 (novel coronavirus disease 2019). We systematically reviewed mortality in COVID-19 patients with ARDS and the potential role of systemic corticosteroids in COVID-19 patients.

METHODS

Electronic databases and country-specific healthcare databases were searched to identify relevant studies/reports. The quality assessment of individual studies was conducted using the Newcastle-Ottawa Scale. Country-specific proportion of individuals with COVID-19 who developed ARDS and reported death were combined in a random-effect meta-analysis to give a pooled mortality estimate of ARDS.

RESULTS

The overall pooled mortality estimate among 10,815 ARDS cases in COVID-19 patients was 39% (95% CI: 23-56%). The pooled mortality estimate for China was 69% (95% CI: 67-72%). In Europe, the highest mortality estimate among COVID-19 patients with ARDS was reported in Poland (73%; 95% CI: 58-86%) while Germany had the lowest mortality estimate (13%; 95% CI: 2-29%) among COVID-19 patients with ARDS. The median crude mortality rate of COVID-19 patients with reported corticosteroid use was 28.0% (lower quartile: 13.9%; upper quartile: 53.6%).

CONCLUSIONS

The high mortality in COVID-19 associated ARDS necessitates a prompt and aggressive treatment strategy which includes corticosteroids. Most of the studies included no information on the dosing regimen of corticosteroid therapy, however, low-dose corticosteroid therapy or pulse corticosteroid therapy appears to have a beneficial role in the management of severely ill COVID-19 patients.

The pathophysiology of SARS-CoV-2: A suggested model and therapeutic approach

In this paper, a model is proposed of the pathophysiological processes of COVID-19 starting from the infection of human type II alveolar epithelial cells (pneumocytes) by SARS-CoV-2 and culminating in the development of ARDS. The innate immune response to infection of type II alveolar epithelial cells leads both to their death by apoptosis and pyroptosis and to alveolar macrophage activation. Activated macrophages secrete proinflammatory cytokines and chemokines and tend to polarise into the inflammatory M1 phenotype. These changes are associated with activation of vascular endothelial cells and thence the recruitment of highly toxic neutrophils and inflammatory activated platelets into the alveolar space. Activated vascular endothelial cells become a source of proinflammatory cytokines and reactive oxygen species (ROS) and contribute to the development of coagulopathy, systemic sepsis, a cytokine storm and ARDS. Pulmonary activated platelets are also an important source of proinflammatory cytokines and ROS, as well as exacerbating pulmonary neutrophil-mediated inflammatory responses and contributing to systemic sepsis by binding to neutrophils to form platelet-neutrophil complexes (PNCs). PNC formation increases neutrophil recruitment, activation priming and extraversion of these immune cells into inflamed pulmonary tissue, thereby contributing to ARDS. Sequestered PNCs cause the development of a procoagulant and proinflammatory environment. The contribution to ARDS of increased extracellular histone levels, circulating mitochondrial DNA, the chromatin protein HMGB1, decreased neutrophil apoptosis, impaired macrophage efferocytosis, the cytokine storm, the toll-like receptor radical cycle, pyroptosis, necroinflammation, lymphopenia and a high Th17 to regulatory T lymphocyte ratio are detailed.

Balancing evidence and frontline experience in the early phases of the COVID-19 pandemic: current position of the Italian Society of Anti-infective Therapy (SITA) and the Italian Society of Pulmonology (SIP)

BACKGROUND

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of coronavirus disease 2019 (COVID-19), which has rapidly become epidemic in Italy and other European countries. The disease spectrum ranges from asymptomatic/mildly symptomatic presentations to acute respiratory failure. At the present time the absolute number of severe cases requiring ventilator support is reaching or even surpassing the intensive care unit bed capacity in the most affected regions and countries.

OBJECTIVES

To narratively summarize the available literature on the management of COVID-19 in order to combine current evidence and frontline opinions and to provide balanced answers to pressing clinical questions.

SOURCES

Inductive PubMed search for publications relevant to the topic.

CONTENT

The available literature and the authors' frontline-based opinion are summarized in brief narrative answers to selected clinical questions, with a conclusive statement provided for each answer.

IMPLICATIONS

Many off-label antiviral and anti-inflammatory drugs are currently being administered to patients with COVID-19. Physicians must be aware that, as they are not supported by high-level evidence, these treatments may often be ethically justifiable only in those worsening patients unlikely to improve only with supportive care, and who cannot be enrolled onto randomized clinical trials. Access to well-designed randomized controlled trials should be expanded as much as possible because it is the most secure way to change for the better our approach to COVID-19 patients.

Corticosteroids in Acute Lung Injury: The Dilemma Continues

Acute lung injury (ALI) represents a serious heterogenous pulmonary disorder with high mortality. Despite improved understanding of the pathophysiology, the efficacy of standard therapies such as lung-protective mechanical ventilation, prone positioning and administration of neuromuscular blocking agents is limited. Recent studies have shown some benefits of corticosteroids (CS). Prolonged use of CS can shorten duration of mechanical ventilation, duration of hospitalization or improve oxygenation, probably because of a wide spectrum of potentially desired actions including anti-inflammatory, antioxidant, pulmonary vasodilator and anti-oedematous effects. However, the results from experimental vs. clinical studies as well as among the clinical trials are often controversial, probably due to differences in the designs of the trials. Thus, before the use of CS in ARDS can be definitively confirmed or refused, the additional studies should be carried on to determine the most appropriate dosing, timing and choice of CS and to analyse the potential risks of CS administration in various groups of patients with ARDS.

E-Selectin-Binding Peptide-Modified Bovine Serum Albumin Nanoparticles for the Treatment of Acute Lung Injury

Currently, there is no specific treatment for acute lung injury (ALI). E-selectin-binding peptide (Esbp), a high-affinity peptide that delivers drugs targeting inflammatory vascular endothelial cells, can bind to E-selectin and act as a targeting ligand for selective drug delivery. In this study, we coupled the thiol groups of Esbp to the amino groups on the surface of bovine serum albumin (BSA) using succinimidyl iodoacetic acid to make Esbp-modified BSA nanoparticles (BSANPs) at the average ratio of 19.3 μg Esbp to 1 mg BSA. The Esbp-modified BSANPs were spherical in shape and had a particle size of 266.7 ± 2.7 nm, polydispersity index of 0.165 ± 0.02, zeta potential of - 33.64 ± 1.23 mV, encapsulation efficiency of 84.3 ± 2.3%, and drug loading of 6.7 ± 0.32%. The cumulative release rate of dexamethasone-loaded Esbp-modified BSANPs was 51.2% within 12 h, significantly lower than that of 88.2% of free drugs. Moreover, Esbp-modified BSANPs could be uptaken in vitro by activated human umbilical vein endothelial cells and in vivo by the lungs of the established ALI mouse model. These results indicated that our Esbp-modified BSANPs delivery system has characteristics of good targeting ability and biocompatibility and is able to inhibit inflammation. Overall, our Esbp-modified BSANPs delivery system has therapeutic potentials as a new targeting drug system for the treatment of ALI in the future.

Glucocorticoid receptor gene expression in a CLP-induced ARDS-like rat model treated with dexamethasone and metyrapone

Glucocorticoids (GCs) are used for acute respiratory distress syndrome (ARDS) to improve or prevent lung injury. The mechanisms underlying the effects of GCs involve inadequate GC-receptor (GR)-mediated downregulation of pro-inflammatory factors despite elevated levels of cortisol. Within this context, knowledge of the transcriptional pattern of the GR gene in response to variations in physiological parameters may shed light on this issue. We addressed this problem by measuring plasmatic corticosterone (CCT) levels and assessing GR expression at transcript and protein levels in rats with caecal ligation and puncture (CLP)-induced ARDS-like syndrome treated with dexamethasone and metyrapone. Seventy male rats were randomized into three main groups: Naïve (any treatment), Sham (caecum-exposed) and CLP. CLP animals were divided into three groups according to pretreatments performed before surgery: CLP sal (0.9% NaCl ip), CLP metyrapone (50 mg.kg-1 ip) and CLP dexamethasone (0.5 mg.kg-1 ip). Our results showed that CLP sal promotes elevation in CCT levels, which are significantly reduced with metyrapone to levels comparable to untreated animals when dexamethasone is used. In this hormonal milieu, the GR gene transcript levels of both variants, GRα and GRβ, are produced in comparable levels and in response to caecum-exposing surgery. Nonetheless, the expression of the GRα variant demonstrated positive sensitivity to variations in CCT levels and was downregulated in animals treated with dexamethasone. Moreover, nuclear translocation of GR protein decreased with high levels of plasma CCT and higher GR translocation was found in animals with moderate CCT levels; in either case, the process seemed to be positively associated with the CLP procedure.

Early application of low-dose glucocorticoid improves acute respiratory distress syndrome: A meta-analysis of randomized controlled trials

Previous clinical trials have investigated the effect of glucocorticoid therapy in acute respiratory distress syndrome (ARDS), with controversial results, particularly with regard to the early administration of low dose glucocorticoid. The present meta-analysis aimed to assess whether the application of glucocorticoid was able to reduce mortality in patients with ARDS. A literature search was performed using online databases, including MEDLINE, Embase, Cochrane and CNKI regardless of whether the studies were published in English or Chinese. Following assessment via inclusion and exclusion criteria, two reviewers screened controlled randomized trials which investigated glucocorticoid therapy in ARDS patients and independently extracted data. The quality of all of the included trials was evaluated based on blinding, randomization and other methods. A total of 14 studies with 1,441 patients met the inclusion criteria. The results of the meta-analysis demonstrated that glucocorticoid significantly reduced the overall mortality of patients with ARDS [relative ratio (RR), 0.68; 95% confidence interval (CI), 0.50-0.91; P<0.05], particularly with a low-dose of glucocorticoid (RR, 0.57; 95% CI, 0.39-0.84; P<0.05) at the early phase of ARDS (RR, 0.37; 95% CI, 0.16-0.86; P<0.05), and a longer duration of steroids (RR, 0.44; 95% CI, 0.30-0.64; P<0.05). Administration of steroids also significantly increased the number of days that patients remained alive and were off mechanical ventilation (RR, 3.08; 95% CI, 1.49-4.68; P<0.05) without significantly increasing the novel infection rate (RR, 1.00; 95% CI, 0.44-2.25; P<0.05). Due to inconsistencies and other limitations, the quality of the studies used for the meta-analysis of the effect of glucocorticoid on mortality was low. In conclusion, early use of low dose glucocorticoid may effectively reduce mortality in patients with ARDS. However, this conclusion may be affected by the limited quality of the studies included in the present meta-analysis.

Rationale for Prolonged Glucocorticoid Use in Pediatric ARDS: What the Adults Can Teach Us

Based on molecular mechanisms and physiologic data, a strong association has been established between dysregulated systemic inflammation and progression of acute respiratory distress syndrome (ARDS). In ARDS patients, glucocorticoid receptor-mediated downregulation of systemic inflammation is essential to restore homeostasis, decrease morbidity and improve survival and can be significantly enhanced with prolonged low-to-moderate dose glucocorticoid treatment. A large body of evidence supports a strong association between prolonged glucocorticoid treatment-induced downregulation of the inflammatory response and improvement in pulmonary and extrapulmonary physiology. The balance of the available data from eight controlled trials (n = 622) provides consistent strong level of evidence for improving patient-centered outcomes and hospital survival. The sizable increase in mechanical ventilation-free days (weighted mean difference, 6.48 days; CI 95% 2.57-10.38, p < 0.0001) and intensive care unit-free days (weighted mean difference, 7.7 days; 95% CI, 3.13-12.20, p < 0.0001) by day 28 is superior to any investigated intervention in ARDS. For treatment initiated before day 14 of ARDS, the increased in hospital survival (70 vs. 52%, OR 2.41, CI 95% 1.50-3.87, p = 0.0003) translates into a number needed to treat to save one life of 5.5. Importantly, prolonged glucocorticoid treatment is not associated with increased risk for nosocomial infections (22 vs. 27%, OR 0.61, CI 95% 0.35-1.04, p = 0.07). Treatment decisions involve a tradeoff between benefits and risks, as well as costs. This low-cost, highly effective therapy is familiar to every physician and has a low risk profile when secondary prevention measures are implemented.

Dexamethasone ameliorates H₂S-induced acute lung injury by alleviating matrix metalloproteinase-2 and -9 expression

Acute lung injury (ALI) is one of the fatal outcomes after exposure to high levels of hydrogen sulfide (H₂S), and the matrix metalloproteinases (MMPs) especially MMP-2 and MMP-9 are believed to be involved in the development of ALI by degrading the extracellular matrix (ECM) of blood-air barrier. However, the roles of MMP-2 and MMP-9 in H₂S-induced ALI and the mechanisms of dexamethasone (DXM) in treating ALI in clinical practice are still largely unknown. The present work was aimed to investigate the roles of MMP-2 and MMP-9 in H₂S-induced ALI and the protective effects of DXM. In our study, SD rats were exposed to H₂S to establish the ALI model and in parallel, A549 cells were incubated with NaHS (a H₂S donor) to establish cell model. The lung HE staining, immunohistochemisty, electron microscope assay and wet/dry ratio were used to identify the ALI induced by H₂S, then the MMP-2 and MMP-9 expression in both rats and A549 cells were detected. Our results revealed that MMP-2 and MMP-9 were obviously increased in both mRNA and protein level after H₂S exposure, and they could be inhibited by MMP inhibitor doxycycline (DOX) in rat model. Moreover, DXM significantly ameliorated the symptoms of H₂S-induced ALI including alveolar edema, infiltration of inflammatory cells and the protein leakage in BAFL via up-regulating glucocorticoid receptor(GR) to mediate the suppression of MMP-2 and MMP-9. Furthermore, the protective effects of DXM in vivo and vitro study could be partially blocked by co-treated with GR antagonist mifepristone (MIF). Our results, taken together, demonstrated that MMP-2 and MMP-9 were involved in the development of H₂S-induced ALI and DXM exerted protective effects by alleviating the expression of MMP-2 and MMP-9. Therefore, MMP-2 and MMP-9 might represent novel pharmacological targets for the treatment of H₂S and other hazard gases induced ALI.

The influence of prehospital systemic corticosteroid use on development of acute respiratory distress syndrome and hospital outcomes

OBJECTIVE

The role of systemic corticosteroids in pathophysiology and treatment of acute respiratory distress syndrome is controversial. Use of prehospital systemic corticosteroid therapy may prevent the development of acute respiratory distress syndrome and improve hospital outcomes.

DESIGN

This is a preplanned retrospective subgroup analysis of the prospectively identified cohort from a trial by the U.S. Critical Illness and Injury Trials Group designed to validate the Lung Injury Prediction Score.

SETTING

Twenty-two acute care hospitals.

PATIENTS

: Five thousand eighty-nine patients with at least one risk factor for acute respiratory distress syndrome at the time of hospitalization.

INTERVENTION

Propensity-based analysis of previously recorded data.

MEASUREMENTS AND MAIN RESULTS

Three hundred sixty-four patients were on systemic corticosteroids. Prevalence of acute respiratory distress syndrome was 7.7% and 6.9% (odds ratio, 1.1 [95% CI, 0.8-1.7]; p = 0.54) for patients on systemic corticosteroid and not on systemic corticosteroids, respectively. A propensity for being on systemic corticosteroids was derived through logistic regression by using all available covariates. Subsequently, 354 patients (97%) on systemic corticosteroids were matched to 1,093 not on systemic corticosteroids by their propensity score for a total of 1,447 patients in the matched set. Adjusted risk for acute respiratory distress syndrome (odds ratio, 0.96 [95% CI, 0.54-1.38]), invasive ventilation (odds ratio, 0.84 [95% CI, 0.62-1.12]), and in-hospital mortality (odds ratio, 0.97 [95% CI, 0.63-1.49]) was then calculated from the propensity-matched sample using conditional logistic regression model. No significant associations were present.

CONCLUSIONS

Prehospital use of systemic corticosteroids neither decreased the development of acute respiratory distress syndrome among patients hospitalized with at one least risk factor, nor affected the need for mechanical ventilation or hospital mortality.

Do corticosteroids improve outcome for any critical illness?

PURPOSE OF REVIEW

Corticosteroids have been widely administered in critically ill patients for various indications. Their clinical benefit is broadly investigated but remains controversial. The purpose of this review is to explore the use of corticosteroids in intensive care, their impact on patient outcome and to provide practical guidance for the use of corticosteroids in the ICU.

RECENT FINDINGS

Critical illness is the result of significant tissue damage, due to cellular ischemia, trauma or infection, inducing a systemic inflammatory syndrome. Recent advances in the understanding of the immunologic and molecular mechanisms of inflammation support, in part, the conceptual use of corticosteroids as an adjunct immunomodulatory therapy. But use of corticosteroids carries the risk of severe adverse effects, partly because of their anti-infammatory effects. Recently, clinical research has focused on critical illness-related corticosteroid insufficiency and several trials investigated the role of corticosteroids therapy in septic and critically ill patients with severe systemic inflammation such as acute respiratory distress syndrome, severe community-acquired pneumonia and meningitis. Improved morbidity has been demonstrated in some studies but a clear benefit in term of mortality was not observed.

SUMMARY

Critical illnesses stem from a group of heterogeneous medical conditions. Failure to target subgroups more likely to benefit from the use of corticosteroids may be one explanation for the largely disappointing results in clinical trials, thus, far.

Is prolonged low-dose glucocorticoid treatment beneficial in community-acquired pneumonia?

Community-acquired pneumonia (CAP) has a significant impact on public health in terms of short-term and long-term morbidity and mortality. Irrespective of microbiological etiology, the host's inability to fully downregulate systemic inflammation is the dominant pathogenetic process contributing to acute and long-term morbidity and mortality in CAP. Glucocorticoids are the natural regulators of inflammation, and their production increases during infection. There is consistent evidence that downregulation of systemic inflammation with prolonged low-dose glucocorticoid treatment in patients with severe sepsis and acute respiratory distress syndrome improves cardiovascular and pulmonary organ physiology. A recent meta-analysis of pooled controlled small trials (n = 970) of patients admitted with CAP found improved short-term mortality in the subgroup with severe CAP and/or receiving >5 days of glucocorticoid treatment. We have expanded on this meta-analysis by including patients with CAP recruited in trials investigating prolonged low-dose glucocorticoid treatment in septic shock and/or early acute respiratory distress syndrome (n = 1,206). Our findings confirm a survival advantage for severe CAP (RR 0.66, 95% confidence interval 0.51-0.84; p = .001). A large randomized trial is in progress to confirm the aggregate findings of these small trials and to evaluate the long-term effect of this low-cost treatment.