Leonardo Pedrazza

Gallic acid reduces the effect of LPS on apoptosis and inhibits the formation of neutrophil extracellular traps

Apoptosis and NETosis of neutrophils are two major mechanisms of programmed cell death that differ in their morphological characteristics and effects on the immune system. Apoptosis can be delayed by the presence of pathogens or chemical components such as lipopolysaccharide (LPS). Neutrophils have other antimicrobial strategy, called neutrophil extracellular traps (NETs), which contributes to the elimination and control of the pathogen. NETosis is induced by infection, inflammation or trauma and represents an innate immune activation mechanism. The objective of this study was to evaluate the effect of gallic acid (GA) in the modulation of apoptosis and NETs release. The results show that GA decreased the anti-apoptotic effect of LPS, blocked the induction of NETs and prevented the formation of free radicals induced by LPS. These findings demonstrate that the GA is a novel therapeutic agent for decreasing the exacerbated response of the body against an infectious agent.

Ecto-nucleotidase pathway is altered by different treatments with fluoxetine and nortriptyline.

Depression is one of the most disabling diseases and causes a significant burden to both individual and society. Selective serotonin reuptake inhibitors and tricyclic antidepressants, such as fluoxetine and nortriptyline, respectively, are commonly used in treatment for depression. These antidepressants were tested on cerebral cortex and hippocampal synaptosomes after acute and chronic in vivo and in vitro treatments. In chronic treatment, fluoxetine and nortriptyline decreased ATP hydrolysis (17.8% and 16.3%, respectively) in hippocampus. In cerebral cortex, nortriptyline increased ATP (32.3%), ADP (51.8%), and AMP (59.5%) hydrolysis. However, fluoxetine decreased ATP (25.5%) hydrolysis and increased ADP (80.1%) and AMP (33.3%) hydrolysis. Significant activation of ADP hydrolysis was also observed in acute treatment with nortriptyline (49.8%) in cerebral cortex. However, in hippocampus, ATP (24.7%) and ADP (46.1%) hydrolysis were inhibited. Fluoxetine did not alter enzyme activities in acute treatment for both structures. In addition, there were significant changes in NTPDase activities when fluoxetine and nortriptyline (100, 250, and 500 microM) were tested in vitro. There was no inhibitory effect of fluoxetine and nortriptyline on AMP hydrolysis in cerebral cortex and hippocampus. The findings showed that these antidepressant drugs can affect the ecto-nucleotidase pathway, suggesting that the extracellular adenosine levels could be modulated by these drugs.

Biochemical and inflammatory aspects in patients with severe sepsis and septic shock: The predictive role of IL-18 in mortality

BACKGROUND Sepsis is a major health care problem, with a significant mortality rate in intensive care units. We evaluated biochemical and inflammatory markers in patients with severe sepsis and septic shock and its association of with mortality rates. METHODS Critically ill patients with diagnoses of sepsis - severe sepsis group (n=23) and septic shock group (n=25), and a control group (n=17) were recruited within 24h of entry into the ICU. Serum levels of inflammatory mediators were measured (IL-1β, IL-6, IL-8, IL-10, TNF-α, IL-18 and nitric oxide). We have also collected clinical parameters and laboratorial tests to estimate severity and organ dysfunction (APACHE II, SOFA, lactate). These results were compared between survivors and no survivors. RESULTS IL-18 was directly related to mortality independently of other inflammatory mediators, especially IL-1β, although the inflammatory pathway is closely linked to inflammasome activation and both have simultaneous release in the infectious process. Mortality was directly proportional to IL-18 plasma levels, which did not occur with other inflammatory mediators. CONCLUSIONS IL-18 is an important predictor of mortality in humans with both severe sepsis and septic shock, independent of IL-1β.

Gallic acid reduces cell growth by induction of apoptosis and reduction of IL-8 in HepG2 cells.

Hepatocellular carcinoma is the most prevalent primary liver tumor and is among the top ten cancer that affect the world population. Its development is related, in most cases, to the existence of chronic liver injury, such as in cirrhosis. The knowledge about the correlation between chronic inflammation and cancer has driven new researches with anti-inflammatory agents that have potential for the development of antitumor drugs. Gallic acid is a phenolic acid found in many natural products and have shown anti-inflammatory, anti-tumor, anti-mutagenic and antioxidant actions. The purpose of this study was to investigate the effect of gallic acid on acute and chronic cell proliferation and inflammatory parameters of hepatocellular carcinoma cells (HepG2), as well as to investigate the mechanisms involved. Results showed that the gallic acid decreased the proliferation of HepG2 cells in a dose-dependent manner (Trypan blue exclusion assay), without causing necrosis (LDH assay). We observed a significant increase in the percentage of small and regular nuclei (Nuclear Morphometric Analysis assay), a significant induction of apoptosis by Annexin V-FITC and PI assay and no interference with the cell cycle using the FITC BrdU Flow Kit. We observed a significant reduction in the levels of IL-8 and increased levels of IL-10 and IL-12 (Cytometric Bead Array Human Inflammation Assay). Furthermore, gallic acid caused no cancer cells regrowth at a long term (Cumulative Population Doubling assay). According to these results, gallic acid showed a strong potential as an anti-tumor agent in hepatocellular carcinoma cells.

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.

Therapeutic ultrasound stimulates MC3T3-E1 cell proliferation through the activation of NF-κB1, p38α, and mTOR

As the population ages, osteometabolic diseases and osteoporotic fractures emerge, resulting in substantial healthcare resource utilization and impaired quality of life. Many types of mechanical stimulation have the potential of being recognized by bone cells after a mechanical sign is transformed into a biological one (a process called mechanotransduction). The therapeutic ultrasound (TU) is one of several resources capable of promoting bone cell mechanical stimulation. Therefore, the main purpose of present study was to evaluate the effect of TU on the proliferation of pre‐osteoblasts using in vitro bioassays.

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.

Octyl gallate reduces ATP levels and Ki67 expression leading HepG2 cells to cell cycle arrest and mitochondria-mediated apoptosis

Octyl gallate (OG) is an antioxidant that has shown anti-tumor, anti-diabetic and anti-amyloidogenic activities. Mitochondria play an important role in hepatocellular carcinoma, mainly by maintaining accelerated cellular proliferation through the production of ATP. Thus, the mitochondria may be a target for antitumor therapies. Here, we investigated the effects of OG in the hepatocarcinoma cell line (HepG2) and the mechanisms involved. We report, for the first time, that treatment with OG for 24h inhibited HepG2 cell growth by decreasing mitochondrial activity and mass, which led to the reduction of ATP levels. This reduction in the energy supply triggered a decrease in Ki67 protein expression, leading cells to cycle arrest. In addition, treatment with two doses of OG for 48h induced loss of mitochondrial functionality, mitochondrial swelling and apoptosis. Finally, we report that HepG2 cells had no resistance to treatment after multiple doses. Collectively, our findings indicate that metabolic dysregulation and Ki67 protein reduction are key events in the initial anti-proliferative action of OG, whereas mitochondrial swelling and apoptosis induction are involved in the action mechanism of OG after prolonged exposure. This suggests that OG targets mitochondria, thus representing a candidate for further research on therapies for hepatocarcinoma.

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.

Immediate Effects of Chest Physiotherapy on Hemodynamic, Metabolic, and Oxidative Stress Parameters in Subjects With Septic Shock

BACKGROUND: Septic shock presents as a continuum of infectious events, generating tissue hypoxia and hypovolemia, and increased oxidative stress. Chest physiotherapy helps reduce secretion, improving dynamic and static compliance, as well as improving secretion clearance and preventing pulmonary complications. The purpose of this study was to evaluate the immediate effect of chest physiotherapy on hemodynamic, metabolic, inflammatory, and oxidative stress parameters in subjects in septic shock. METHODS: We conducted a quasi-experimental study in 30 subjects in septic shock, who underwent chest physiotherapy, without associated heart diseases and with vasopressors < 0.5 μg/kg/min. Venous and arterial blood gases, clinical and hemodynamic data, inflammatory data, lactate, and oxidative stress were evaluated before and 15 min after physiotherapy. RESULTS: Thirty subjects with a mean age of 61.8 ± 15.9 y and Sequential Organ Failure Assessment of 8 (range 6–10) were included. Chest physiotherapy caused a normalization of pH (P = .046) and PaCO2 (P = .008); reduction of lactate (P = .001); and an increase in PaO2 (P = .03), arterial oxygen saturation (P = .02), and PaO2/FIO2 (P = .034), 15 min after it was applied. CONCLUSIONS: The results indicate that chest physiotherapy has immediate effects, improving oxygenation and reducing lactate and oxidative damage in subjects in septic shock. However, it does not cause alterations in the inflammatory and hemodynamic parameters.