Air particulate matter SRM 1648a primes macrophages to hyperinflammatory response after LPS stimulation.

OBJECTIVE: Exposure to air particulate matter (PM) is associated with chronic inflammatory and autoimmune diseases. Macrophages are responsible for the regulation of chronic inflammation. However, whether PM affects macrophage polarization remains unclear. The aim of this study was to evaluate whether nontoxic concentrations of urban PM are able to prime macrophages to altered inflammatory response upon LPS challenge. METHODS: We used two forms of the urban particulate matter SRM 1648a, intact PM and PM deprived of organic compounds (PM∆C). Peritoneal murine macrophages were exposed to different concentrations of PM for 24 h and then challenged with LPS. Production of inflammatory mediators by macrophages was measured to test immunostimulatory/priming capacity of PM. RESULTS: Particulate matter used at non-cytotoxic concentrations induced a dose-dependent production of proinflammatory cytokines (TNF-α, IL-6, IL-12p40). By contrast, PM∆C were not able to stimulate macrophages. However, macrophages primed with both forms of PM show proinflammatory response upon LPS challenge. CONCLUSIONS: Our data indicate that exposure of macrophages to low concentrations of PM may prime the cells to hyperinflammatory response upon contact with LPS. Further studies are necessary to explain whether the exposure of patients suffering from chronic inflammatory diseases to particulate matter is responsible for the exacerbation of clinical symptoms during bacterial infections.

Air pollution, oxidative stress, and exacerbation of autoimmune diseases.

A number of epidemiological studies have shown a strong association between exposure to ambient airborne particulate matter (PM 2.5, PM < 1.0) and lung or cardiovascular diseases characterised by high mortality and morbidity. However, much less is known about the role of air pollution in the pathogenesis of autoimmune diseases, which constitutes a significant problem in modern society. This paper summarises the state of current research regarding the influence of PM on the development and/or progression of autoimmune diseases. A brief review of the great body of research concerning pathogenesis of autoimmune disorders is presented. Then, the scope of our review is narrowed to the research related to the impact of particulate matter on oxidative and nitrosative stress, as well as exacerbation of chronic inflammation, because they can contribute to the development of autoimmune diseases. Moreover, we discuss the impact of various components of PM (metal, organic compounds) on PM toxicity and the ability to generate oxidants.

Distinct effects of Lactobacillus plantarum KL30B and Escherichia coli 3A1 on the induction and development of acute and chronic inflammation.

OBJECTIVE: Enteric bacteria are involved in the pathogenesis of ulcerative colitis. In experimental colitis, a breakdown of the intestinal epithelial barrier results in inflow of various gut bacteria, induction of acute inflammation and finally, progression to chronic colitis. MATERIAL AND METHODS: In the present study we compared pro-inflammatory properties of two bacterial strains isolated from human microbiome, Escherichia coli 3A1 and Lactobacillus plantarum KL30B. The study was performed using two experimental models of acute inflammation: peritonitis in mice and trinitrobenzenesulfonic acid (TNBS)-induced colitis in rats. RESULTS: Both bacterial strains induced massive neutrophil infiltration upon injection into sterile peritoneal cavity. However, peritoneal exudate cells stimulated in vitro with E. coli 3A1, produced far more nitric oxide, than those stimulated with L. plantarum KL30B. Interestingly, distinct effect on the development of TNBS-induced colitis was observed after oral administration of the tested bacteria. Lactobacillus plantarum KL30B evoked strong acute colitis. On the contrary, the administration of E. coli 3A1 resulted in a progression of colitis to chronicity. CONCLUSIONS: Our results show that distinct effects of bacterial administration on the development of ongoing inflammation is strain specific and depends on the final effect of cross-talk between bacteria and cells of the innate immune system.

Staphylococcus epidermidis and biofilm-associated neutrophils in chronic rhinosinusitis. A pilot study.

A key role of bacterial biofilm in the pathogenesis of chronic rhinosinusitis (CRS) with (CRSwNP) and without nasal polyps (CRSsNP) is commonly accepted. However, the impact of some bacterial species isolated from inflamed sinus mucosa on biofilm formation is unclear. In particular, the role of Staphylococcus epidermidis as aetiological agents of CRS is controversial. Moreover, the effect of biofilm formation on neutrophil infiltration and activity in CRSwNP calls for explanation. In this study, biofilms were found in three of 10 patients (mean age = 46 ± 14) with CRS undergoing endoscopic sinus surgery by means of scanning electron microscopy. Unexpectedly, S. epidermidis was the primary isolated bacteria and was also found to be present in all biofilm-positive mucosa specimens, indicating its pivotal role in the pathogenesis of severe chronic infections associated with biofilm formation. We have also measured the activity of myeloperoxidase (MPO), the most abundant neutrophil enzyme, to demonstrate the presence of neutrophils in the samples tested. Our present results show that the level of MPO in CRS associated with biofilm is lower than that without biofilm. It may suggest either a low number of neutrophils or the presence of a type of neutrophils with compromised antimicrobial activity, described as biofilm-associated neutrophils (BAN). Finally, we conclude that further studies with a large number of CRS cases should be performed to establish the association between S. epidermidis and other frequently isolated bacterial species from paranasal sinuses, with the severity of CRS, biofilm formation and the infiltration of BAN.

[Ebola virus disease]. / Ebola virus disease.

Ebola is one of the most virulent zoonotic RNA viruses causing in humans haemorrhagic fever with fatality ratio reaching 90%. During the outbreak of 2014 the number of deaths exceeded 8.000. The "imported" cases reported in Western Europe and USA highlighted the extreme risk of Ebola virus spreading outside the African countries. Thus, haemorrhagic fever outbreak is an international epidemiological problem, also due to the lack of approved prevention and therapeutic strategies. The editorial review article briefly summarizes current knowledge on Ebola virus disease epidemiology, etiology, pathogenesis, clinical presentation, diagnosis as well as possible prevention and treatment.

Angiotensin AT1 receptor antagonists enhance the anticonvulsant action of valproate in the mouse model of maximal electroshock.

Angiotensin AT1 receptor antagonists, drugs affecting the renin-angiotensin system, are commonly used in the treatment of hypertension and congestive heart failure. It is also known that the renin-angiotensin system exists in the brain and therefore it may be involved in the regulation of seizure susceptibility. The aim of the current study was to evaluate the effects of losartan (2-n-butyl-4-chloro-5-hydroxymethyl-1-[(2'(1H-tetrazol-5-yl)-biphenil-4-yl)methyl]imidazole) and telmisartan (49-[(1,49-dimethyl-29-propyl[2,69-bi-1H-benzimidazo]-19-yl)methyl]-[1,19-biphenyl]-2-carboxylic acid), the angiotensin AT1 receptor antagonists which are widely used in clinical practice, on the protective action of conventional antiepileptic drugs (carbamazepine, phenytoin, valproate and phenobarbital) against maximal electroshock-induced seizures in mice. Losartan (10, 20 and 50 mg/kgi.p.) and telmisartan (5, 10 and 30 mg/kgi.p.) did not influence the threshold for electroconvulsions. However, both drugs potentiated the anticonvulsant activity of valproate. Losartan (50 mg/kgi.p.) decreased its ED50 value from 249.8 to 194.6 mg/kg while telmisartan (30 mg/kgi.p.) lowered the ED50 value for valproate from 249.8 to 190.6 mg/kg. The antiseizure action of the remaining antiepileptics was not affected by losartan or telmisartan. The observed interactions between tested angiotensin AT1 receptor antagonists and valproate were pharmacodynamic in nature as either losartan or telmisartan did not alter total brain concentrations of valproate. This finding can be important for epileptic patients receiving valproate and also angiotensin AT1 receptor antagonists due to other medical causes.