Staphylococcal toxic shock syndrome toxin-1 induces the translocation and secretion of high mobility group-1 protein from both activated T cells and monocytes

The Protective Effects of Peroxisome Proliferator-Activated Receptor Gamma in Cerebral Ischemia-Reperfusion Injury

Cerebral ischemia-reperfusion injury (CI/RI) is a complex pathological process that often occurs secondary to trauma, surgery, and shock. Peroxisome proliferator activated receptor gamma (PPARγ) is a subunit of the PPAR and is a ligand-activated nuclear transcription factor. After being activated by its ligand, PPARγ can combine with specific DNA response elements to regulate the transcription and expression of genes. It has a wide range of biological functions, such as regulating lipid metabolism, improving insulin sensitivity, modulating anti-tumor mechanisms, and inhibiting inflammation. In recent years, some studies have shown that PPARγ exerts a protective effect during CI/RI. This article aims to summarize the research progress of studies that have investigated the protective effects of PPARγ in CI/RI and the cellular and molecular mechanisms through which these effects are modulated, including inhibition of excitatory amino acid toxicity, reduced Ca2+ overload, anti-oxidative stress, anti-inflammation, inhibition of microglial activation, maintain the BBB, promotion of angiogenesis, and neurogenesis and anti-apoptotic processes.

Role of peroxisome proliferator-activated receptors in stroke prevention and therapy-The best is yet to come?

Role of peroxisome proliferator-activated receptors (PPARs) in the pathophysiology of stroke and protective effects of PPAR ligands have been widely investigated in the last 20 years. Activation of all three PPAR isoforms, but especially PPAR-γ, was documented to limit postischemic injury in the numerous in vivo, as well as in in vitro studies. PPARs have been demonstrated to act on multiple mechanisms and were shown to activate multiple protective pathways related to inflammation, apoptosis, BBB protection, neurogenesis, and oxidative stress. The aim of this review was to summarize two decades of PPAR research in stroke with emphasis on in vivo animal studies. We focus on each PPAR receptor separately and detail their implication in stroke. This review also discusses recent clinical efforts in the field and the epidemiological data with regard to role of PPAR polymorphisms in susceptibility to stroke, and tries to draw conclusions and describe future perspectives.

Staphylococcus aureus infections: epidemiology, pathophysiology, clinical manifestations, and management

Staphylococcus aureus is a major human pathogen that causes a wide range of clinical infections. It is a leading cause of bacteremia and infective endocarditis as well as osteoarticular, skin and soft tissue, pleuropulmonary, and device-related infections. This review comprehensively covers the epidemiology, pathophysiology, clinical manifestations, and management of each of these clinical entities. The past 2 decades have witnessed two clear shifts in the epidemiology of S. aureus infections: first, a growing number of health care-associated infections, particularly seen in infective endocarditis and prosthetic device infections, and second, an epidemic of community-associated skin and soft tissue infections driven by strains with certain virulence factors and resistance to β-lactam antibiotics. In reviewing the literature to support management strategies for these clinical manifestations, we also highlight the paucity of high-quality evidence for many key clinical questions.

The combination of a tumor necrosis factor inhibitor and antibiotic alleviates staphylococcal arthritis and sepsis in mice

BACKGROUND

Despite advances in medical practices, in recent decades permanent reductions in joint function have not been achieved, and the high mortality rate of patients with staphylococcal septic arthritis has not substantially improved.

METHODS

We evaluated the effects of a combined tumor necrosis factor (TNF) inhibitor and antibiotic therapy on the course of Staphylococcus aureus arthritis and sepsis in mice.

RESULTS

Treatment with the combination of a TNF inhibitor and an antibiotic resulted in a quicker relief of clinical arthritis in mice with septic arthritis, compared with an antibiotic monotherapy. Both histopathologically verified synovitis and the extent of joint destruction were reduced by this combined treatment. Importantly, anti-TNF treatment significantly improved the survival rate of mice with S. aureus sepsis and staphylococcal enterotoxin shock syndrome; this effect might be the result of a partial restoration of the hemostatic balance between coagulation and fibrinolysis. Finally, we demonstrated that anti-TNF treatment downregulates high-mobility group protein B1 in staphylococcal enterotoxin shock syndrome.

CONCLUSIONS

Thus, simultaneous systemic TNF inhibition and antibiotic therapy has beneficial effects on the outcome of S. aureus arthritis and sepsis in a mouse model, suggesting that the combination of a TNF inhibitor and antibiotics represents a novel therapeutic strategy for the treatment of staphylococcal infections.

The value of procalcitonin and the SAPS II and APACHE III scores in the differentiation of infectious and non-infectious fever in the ICU: a prospective, cohort study

Early and accurate differentiation between infectious and non-infectious fever is vitally important in the intensive care unit (ICU). In the present study, patients admitted to the medical ICU were screened daily from August 2008 to February 2009. Within 24 hr after the development of fever (>38.3℃), serum was collected for the measurement of the procalcitonin (PCT) and high mobility group B 1 levels. Simplified Acute Physiology Score (SAPS) II and Acute Physiology And Chronic Health Evaluation (APACHE) III scores were also analyzed. Sixty-three patients developed fever among 448 consecutive patients (14.1%). Fever was caused by either infectious (84.1%) or non-infectious processes (15.9%). Patients with fever due to infectious causes showed higher values of serum PCT (7.8±10.2 vs 0.5±0.2 ng/mL, P=0.026), SAPS II (12.0±3.8 vs 7.6±2.7, P=0.006), and APACHE III (48±20 vs 28.7±13.3, P=0.039) than those with non-infectious fever. In receiver operating characteristic curve analysis, the area under the curve was 0.726 (95% CI; 0.587-0.865) for PCT, 0.759 (95% CI; 0.597-0.922) for SAPS II, and 0.715 (95% CI; 0.550-0.880) for APACHE III. Serum PCT, SAPS II, and APACHE III are useful in the differentiation between infectious and non-infectious fever in the ICU.

Linking innate and adaptive immunity: human Vgamma9Vdelta2 T cells enhance CD40 expression and HMGB-1 secretion

γδ T cells play an important role in regulating the immune response to stress stimuli; however, the mean by which these innate lymphocytes fulfill this function remains poorly defined. The main subset of human peripheral blood γδ T cells responds to nonpeptidic antigens, such as isopentylpyrophosphate (IPP), a metabolite in the mevalonate pathway for both eukaryote and prokaryote cells. IPP-primed γδ T cells significantly augment the inflammatory response mediated by monocytes and αβ T cells to TSST-1, the staphylococcal superantigen that is the major causative agent of toxic shock syndrome. Here we show that the small pool of activated peripheral γδ T cells induces an early upregulation of CD40 on monocytes and the local release of High Mobility Group Box-1 (HMGB-1), the molecule designated as the late mediator of systemic inflammation. This finding provides a new basis for how γδ T cells may serve as influential modulators of both endogenous and exogenous stress stimuli.