The hypothalamic-pituitary-adrenal axis and low-dose glucocorticoids in the treatment of septic shock

Quality assessment of meta-analyses evaluating randomized clinical trials to improve the prognosis of septic shock: an overview of systematic reviews

Objective: Clinical guidelines for the treatment of septic shock are based on the studies with the best scientific evidence, which are meta-analyses of clinical trials. However, these meta-analyses may have methodological limitations that prevent their conclusions from being extrapolated to routine clinical practice. Therefore, the objective of this study is to determine the quality of these meta-analyses through a systematic review.Methods: In this systematic review, we searched MEDLINE, Scopus and EMBASE from inception to May 2019. We selected meta-analyses from clinical trials that determined the effectiveness of an intervention in reducing the incidence of mortality in patients with septic shock. All items were extracted from the Overview Quality Assessment Questionnaire (OQAQ), which collects information from both systematic reviews and meta-analyses.Results: A total of 34 studies were included. Most elements of the OQAQ were conducted satisfactorily, although 35.3% of meta-analyses did not use a quality assessment of the studies included in other analyses. In 52.9% of meta-analyses, the quality of the studies was high or very high.Conclusions: The methods used to obtain the results should be taken into account when recommending an intervention to treat septic shock if the evidence comes from a meta-analysis of the analyzed characteristics.

Enhanced resistance of restraint-stressed mice to sepsis

Sepsis remains a major health concern across the world. The effects of stress on host resistance to sepsis are still not very clear. To explore the effects of chronic stress on sepsis(') we examined the impact of restraint stress on the resistance of mice to sepsis. Interestingly, it was found that restraint stress enhanced the antisepsis resistance of mice and the concentrations of the proinflammatory cytokines IL-1, IL-6, IL-12, and TNF-alpha in the blood of stressed mice were dramatically reduced post Escherichia coli infection or LPS treatment as compared with that of controls (p < 0.05). In addition, the mRNA expressions of glucocorticoid-induced leucine zipper (GILZ) were up-regulated in the spleen and peritoneal macrophages of mice receiving restraint stress or dexamethasone treatment. These results demonstrate that restraint stress enhances the resistance of mice to sepsis, supporting corticotherapy for sepsis and proposing restraint-stressed mouse as an animal model to elucidate mechanisms of stress-associated, antisepsis resistance.

RU486 did not exacerbate cytokine release in mice challenged with LPS nor in db/db mice

Background

Glucocorticoids down-regulate cytokine synthesis and suppress inflammatory responses. The glucocorticoid receptor (GR) antagonist RU486 may exacerbate the inflammatory response, and concerns over this exacerbation have limited the development and clinical use of GR antagonists in the treatment of diabetes and depression. We investigated the effects of RU486 on serum cytokines in db/db mice and on lipopolysaccharide (LPS)-induced circulating TNFα levels in both normal AKR mice and diet-induced obese (DIO) C57BL/6 mice.

Results

Chronic treatment of db/db mice with RU486 dose-dependently decreased blood glucose, increased serum corticosterone and ACTH, but did not affect serum MCP-1 and IL-6 levels. LPS dose-dependently increased serum TNFα in both AKR and C57BL/6 DIO mice, along with increased circulating corticosterone and ACTH. Pretreatment of the mice with RU486 dose-dependently suppressed the LPS induced increases in serum TNFα and further increased serum corticosterone.

Conclusion

RU486 at doses that were efficacious in lowering blood glucose did not exacerbate cytokine release in these three mouse models. RU486 actually suppressed the lower dose LPS-mediated TNFα release, possibly due to the increased release of glucocorticoids.

Pathophysiology of Mifepristone-Induced Septic Shock Due toClostridium sordellii

OBJECTIVE:

To explain the role of mifepristone in medical abortions that results in fulminant and lethal septic shock due to Clostridium sordellii.

DATA SOURCES:

MEDLINE, PubMed, and Google Scholar databases were searched (1984–March 2005%). Key search terms were mifepristone, RU38486, RU486, Mifeprex, medical abortion, septic shock, innate immune system, cytokines, and Clostridium sordellii.

STUDY SELECTION AND DATA EXTRACTION:

All articles identified from the data sources were evaluated and all information deemed relevant was included for the information related to the development of the understanding of the pathophysiology of mifepristone-induced septic shock due to C. sordellii.

DATA SYNTHESIS:

The mechanisms of action of mifepristone were incorporated into the pathophysiology of septic shock due to C. sordellii. Mifepristone, by blocking both progesterone and glucocorticoid receptors, interferes with the controlled release and functioning of cortisol and cytokines. Failure of physiologically controlled cortisol and cytokine responses results in an impaired innate immune system that results in disintegration of the body's defense system necessary to prevent the endometrial spread of C. sordellii infection. The abnormal cortisol and cytokine responses due to mifepristone coupled to the release of potent exotoxins and an endotoxin from C. sordellii are the major contributors to the rapid development of lethal septic shock.

CONCLUSIONS:

Theoretically, it appears that the mechanisms of mifepristone action favor the development of infection that leads to septic shock and intensifies the actions of multiple inflammatory cytokines, resulting in fulminant, lethal septic shock.

Decreasing endogenous glucocorticoids alters the ability of bone marrow cells to produce nitric oxide in response to stimulating agents

Glucocorticoids (GC) are essential for the body to maintain homeostasis. Patients with adrenal insufficiencies suffer from numerous health related problems including increased mortality due to sepsis. Here, we examine bone marrow (BM) cells from mice with adrenal insufficiency for their ability to produce nitric oxide (NO). Mice were injected with metyrapone (MR), an agent that selectively blocks glucocorticoid synthesis. BM cells were removed and tested for NO production. The stimulating agents LPS, TNF-alpha, IL-1beta, and IL-4 were all able to synergize with IFN-gamma, stimulating large concentrations of NO compared to normal mice. An important finding is that BM from injected mice produces NO in response to LPS alone, while normal BM cells do not. Experiments with anti IFN-gamma antibody demonstrate that, in MR injected mice, LPS alone stimulated sufficient quantities of IFN-gamma necessary for NO production. Our results demonstrate that reducing GCs alters regulation of NO production by BM cells at several levels.