Carolina Luft

Carrageenan‐induced inflammation promotes ROS generation and neutrophil extracellular trap formation in a mouse model of peritonitis

Neutrophil extracellular traps (NETs) are a combination of DNA fibers and granular proteins, such as neutrophil elastase (NE). NETs are released in the extracellular space in response to different stimuli. Carrageenan is a sulfated polysaccharide extracted from Chondrus crispus, a marine algae, used for decades in research for its potential to induce inflammation in different animal models. In this study, we show for the first time that carrageenan injection can induce NET release in a mouse model of acute peritonitis. Carrageenan induced NET release by viable neutrophils with NE and myeloperoxidase (MPO) expressed on DNA fibers. Furthermore, although this polysaccharide was able to stimulate reactive oxygen species (ROS) generation by peritoneal neutrophils, NADPH oxidase derived ROS were dispensable for NET formation by carrageenan. In conclusion, our results show that carrageenan‐induced inflammation in the peritoneum of mice can induce NET formation in an ROS‐independent manner. These results may add important information to the field of inflammation and potentially lead to novel anti‐inflammatory agents targeting the production of NETs.

Antioxidant, analgesic and anti-inflammatory effects of lavender essential oil

Several studies have investigated the antinociceptive, immunomodulatory and anti-inflammatory properties of compounds found in the lavender essential oil (LEO), however to date, there is still lack of substantial data. The objective of this study was to assess the antioxidant, anti-inflammatory and antinociceptive effects of lavender essential oil. The 1,1-diphenyl-2-picrylhydrazyl radical decolorization assay was used for antioxidant activity evaluation. The anti-inflammatory activity was tested using two models of acute inflammation: carrageenan-induced pleurisy and croton oil-induced ear edema. The antinociceptive activity was tested using the pain model induced by formalin. LEO has antioxidant activity, which is dose-dependent response. The inflammatory response evoked by carrageenan and by croton oil was reduced through the pre-treatment of animals with LEO. In the pleurisy model, the drug used as positive control, dexamethasone, was more efficacious. However, in the ear swelling, the antiedematogenic effect of the oil was similar to that observed for dexamethasone. In the formalin test, LEO consistently inhibited spontaneous nociception and presented a similar effect to that of tramadol. The results of this study reveal (in vivo) the analgesic and anti-inflammatory activities of LEO and demonstrates its important therapeutic potential.

Mesenchymal Stem Cells Improves Survival in LPS‐induced Acute Lung Injury Acting through Inhibition of NETs Formation

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are syndromes of acute hypoxemic respiratory failure resulting from a variety of direct and indirect injuries to the gas exchange parenchyma of the lungs. During the ALI, we have an increase release of proinflammatory cytokines and high reactive oxygen species (ROS) formation. These factors are responsible for the release and activation of neutrophil‐derived proteases and the formation of neutrophil extracellular traps (NETs). The excessive increase in the release of NETs cause damage to lung tissue. Recent studies have studies involving the administration of mesenchymal stem cells (MSCs) for the treatment of experimental ALI has shown promising results. In this way, the objective of our study is to evaluate the ability of MSCs, in a lipopolysaccharide (LPS)‐induced ALI model, to reduce inflammation, oxidative damage, and consequently decrease the release of NETs. Mice were submitted lung injury induced by intratracheal instillation of LPS and subsequently treated or not with MSCs. Treatment with MSCs was able to modulate pulmonary inflammation, decrease oxidative damage, and reduce the release of NETs. These benefits from treatment are evident when we observe a significant increase in the survival curve in the treated animals. Our results demonstrate that MSCs treatment is effective for the treatment of ALI. For the first time, it is described that MSCs can reduce the formation of NETs and an experimental model of ALI. This finding is directly related to these cells modulate the inflammatory response and oxidative damage in the course of the pathology.

LPS-induced neonatal stress in mice affects the response profile to an inflammatory stimulus in an age and sex-dependent manner.

The aim of this study is to evaluate the response to an inflammatory stimulus in mice exposed to LPS-induced neonatal stress at different ages and sexes. Balb/c mice were submitted to intraperitoneal injections on postnatal days 3 and 10 with lipopolysaccharide (nLPS) or saline solution (nSal). At 21 or 60 days, either saline solution was injected or an inflammatory stimulus was induced by the injection of 1% carrageenan. Inflammatory cytokines, reactive oxygen species, and neutrophil extracellular traps (NETs) production were measured in peritoneal fluid. LPS-induced neonatal stress can reduce inflammatory cytokines in males and females. An increase in NETs production was observed when 60 day nLPS animals were compared to 21 day mice in both sexes. The ROS production was not affected by neonatal stress. The results shown here indicate that LPS-induced neonatal stress can alter cytokine production in response to inflammatory stimuli at different ages, in a sex-dependent effect.

Effects of neonatal inflammation on the inflammatory and oxidative profile during experimental sepsis in adult life

The present study aimed to evaluate the long-term effects of neonatal inflammation on the inflammatory and oxidative profile during experimental sepsis in adult life. Neonatal Balb/c mice received different treatments on day 10: LPS i.p. injection (100g/kg) (nLPS) or saline i.p. injection (nSal). As adults, fear/anxiety behavior was evaluated in the elevated plus maze. The following week, saline solution or LPS was administered and, after 12h, serum (inflammatory cytokines), liver (mitochondrial complexes and oxidative stress) and adrenal gland samples (angiotensin II type 1 and 2 receptors) were collected. There was an increase in the fear/anxiety behavior in the nLPS group. Neonatal administration of LPS increased the mRNA expression of the AT1 receptor and decreased the mRNA expression of the AT2 receptor in the adrenal glands of males. The complexes II and II-III increased in the nLPS saline male group when compared to control. The LPS administration in adult females, regardless of the neonatal treatment, induced a decrease of the glutathione enzyme activity. There were no differences in the inflammatory cytokines. The results showed that neonatal inflammation influenced mitochondrial respiratory chain metabolism and angiotensin II receptors in a sex-dependent manner. Balb/c mice fear and anxiety behaviors in adulthood were programmed by early life inflammatory stress.

Mesenchymal stem cells decrease lung inflammation during sepsis, acting through inhibition of the MAPK pathway

BackgroundSepsis is a severe medical condition that ranks among the top 10 causes of death worldwide and which has permanently high incidence rates. Mesenchymal stem cells (MSCs) have been found to be potent modulators of immune responses. More importantly, there is evidence that MSCs have a beneficial effect on preclinical models of polymicrobial sepsis. However, the changes caused by the MSCs in the effector cells of the host immune system remain unclear.MethodsA mouse model of sepsis (male C57BL/6 mice) with three experimental groups was used for experiments in vivo: a control group, an untreated septic group, and a septic group treated with MSCs. In vitro experiments were performed using a cell line of pulmonary macrophages (RAW 264.7) co-cultured with MSCs and stimulated with lipopolysaccharide (LPS).ResultsIn vivo we demonstrated that treatment with MSCs was able to reduce the expression of cyclooxygenase-2 (COX-2) and nuclear factor kappa B (NF-κB), and thereby decrease the production of inflammatory cytokines. In vitro experiments using a co-culture of macrophages with MSCs showed a decrease in COX-2 and NF-κB, and showed that this reduction was directly related to the ability of MSCs to inhibit phosphorylation of ERK, RSK, and p38, enzymes that belong to the family of mitogen-activated protein kinases (MAPKs).ConclusionsThis study demonstrated that MSCs are able to inhibit the MAPK pathway activation, modulating the inflammatory response during sepsis. This understanding that MSCs can remodel the response of host cells and improve the course of sepsis is essential for developing new treatments for this pathology.

Efeitos de longo prazo do estresse neonatal com lipopolissacarídeo em ratos

Introducao: Diversos modelos experimentais tem sido utilizados para demonstrar que intervencoes no inicio da vida podem gerar alteracoes permanentes que perduram ao longo da vida. A administracao de lipopolissacarideo (LPS) no periodo neonatal gera um estimulo imunologico estressante capaz de alterar muitas respostas fisiologicas ao estresse na vida adulta. Objetivo: Revisar a literatura acerca das influencias, em longo prazo, que a administracao de LPS no periodo neonatal pode gerar na vida adulta em modelos experimentais. Materiais e Metodos: O presente estudo consiste em uma revisao integrativa da literatura com base na busca de artigos cientificos disponiveis nas bases de dados Medline/PubMed e Science Direct , utilizando os descritores neonatal programming , neonatal stress , neonatal LPS e neonatal lipopolysaccharide . Foram incluidas publicacoes cuja tematica abordasse os resultados da utilizacao de LPS como estressor neonatal em protocolos experimentais, sem limite de data. Resultados: Foram selecionados 15 artigos que mostram modelos experimentais em que a injecao de LPS em ratos neonatos causa modificacoes funcionais da resposta do eixo hipotalamo-hipofise-adrenal (HPA) quando adultos, incluindo elevacao nos niveis plasmaticos de corticosterona. Ainda, ha diminuicao das concentracoes circulantes de citocinas pro-inflamatorias, hiperalgesia, aumento na sensibilidade ao estresse e aumento do comportamento de ansiedade e depressao. Conclusao: Os resultados demonstram que a administracao neonatal de LPS consiste em um modelo experimental efetivo de programming , provocando uma serie de alteracoes imunologicas e comportamentais na vida adulta.