Oxidative stress and pyrogenic fever pathogenesis

Emerging mechanisms in the redox regulation of mitochondrial cytochrome c oxidase assembly and function

In eukaryotic cells, mitochondria perform cellular respiration through a series of redox reactions ultimately reducing molecular oxygen to water. The system responsible for this process is the respiratory chain or electron transport system (ETS) composed of complexes I-IV. Due to its function, the ETS is the main source of reactive oxygen species (ROS), generating them on both sides of the mitochondrial inner membrane, i.e. the intermembrane space (IMS) and the matrix. A correct balance between ROS generation and scavenging is important for keeping the cellular redox homeostasis and other important aspects of cellular physiology. However, ROS generated in the mitochondria are important signaling molecules regulating mitochondrial biogenesis and function. The IMS contains a large number of redox sensing proteins, containing specific Cys-rich domains, that are involved in ETS complex biogenesis. The large majority of these proteins function as cytochrome c oxidase (COX) assembly factors, mainly for the handling of copper ions necessary for the formation of the redox reactive catalytic centers. A particular case of ROS-regulated COX assembly factor is COA8, whose intramitochondrial levels are increased by oxidative stress, promoting COX assembly and/or protecting the enzyme from oxidative damage. In this review, we will discuss the current knowledge concerning the role played by ROS in regulating mitochondrial activity and biogenesis, focusing on the COX enzyme and with a special emphasis on the functional role exerted by the redox sensitive Cys residues contained in the COX assembly factors.

Antipyretic effects of Xiangqin Jiere granules on febrile young rats revealed by combining pharmacodynamics, metabolomics, network pharmacology, molecular biology experiments and molecular docking strategies

Xiangqin Jiere granules (XQJRG) is a proprietary Chinese medicine treating children's colds and fevers, but its mechanism of action is unclear. The aim of this study was to explore the antipyretic mechanisms of XQJRG based on pharmacodynamics, non-targeted metabolomics, network pharmacology, molecular biology experiments, molecular docking, and molecular dynamics (MD) simulation. Firstly, the yeast-induced fever model was constructed in young rats to study antipyretic effect of XQJRG. Metabolomics and network pharmacology studies were performed to identify the key compounds, targets and pathways involved in the antipyretic of XQJRG. Subsequently, MetScape was used to jointly analyze targets from network pharmacology and metabolites from metabolomics. Finally, the key targets were validated by enzyme-linked immunosorbent assay (ELISA), and the affinity and stability of key ingredient and targets were evaluated by molecular docking and MD simulation. The animal experimental results showed that after XQJRG treatment, body temperature of febrile rats was significantly reduced, 13 metabolites were significantly modulated, and pathways of differential metabolite enrichment were mainly related to amino acid and lipid metabolism. Network pharmacology results indicated that quercetin and kaempferol were the key active components of XQJRG, TNF, AKT1, IL6, IL1B and PTGS2 were core targets. ELISA confirmed that XQJRG significantly reduced the plasma concentrations of IL-1β, IL-6, and TNF-α, and the hypothalamic concentrations of COX-2 and PGE2. Molecular docking demonstrated that the binding energies of kaempferol to the core targets were all below -5.0 kcal/mol. MD simulation results showed that the binding free energies of TNF-kaempferol, IL6-kaempferol, IL1B-kaempferol and PTGS2-kaempferol were -87.86 kcal/mol, -70.41 kcal/mol, -69.95 kcal/mol and -106.67 kcal/mol, respectively. In conclusion, XQJRG has antipyretic effects on yeast-induced fever in young rats, and its antipyretic mechanisms may be related to the inhibition of peripheral pyrogenic cytokines release by constituents such as kaempferol, the reduction of hypothalamic fever mediator production, and the amelioration of disturbances in amino acid and lipid metabolism.Communicated by Ramaswamy H. Sarma.

Irbesartan has a curative effect on lipopolysaccharide-induced cardiotoxicity by antioxidant and antiapoptotic pathways

INTRODUCTION AND OBJECTIVE

Lipopolysaccharide (LPS) has been associated with myocardial inflammation, oxidative stress, apoptosis, and cardiac dysfunction, as well as death by causing sepsis. In this study, we investigated the effect of irbesartan (IRB), an angiotensin receptor antagonist, on cardiotoxicity caused by LPS.

METHODS

The experiment involved 24 Wistar albino rats divided into three groups of eight: control, LPS (5 mg/kg), and LPS (5 mg/kg)+IRB (3 mg/kg). Parameters including total oxidative status, total antioxidant status, oxidative stress index, and ischemia-modified albumin were measured to assess oxidative stress in heart tissues and serum. Serum CK, CK-MB, and LDH levels were measured spectrophotometrically. RT-qPCR was used to detect the mRNA expression levels of Bcl-2, BAX, p53, caspase-3, and sirtuin 1. Tissues taken from the heart and aorta were examined by immunohistochemistry and histopathology.

RESULTS

While there was an increase in the parameters indicating heart damage, oxidative stress, and apoptosis in the group given LPS, there was an improvement in all parameters and heart damage in the group treated with IRB.

CONCLUSION

As a result of our study, we determined that IRB has an ameliorating effect on myocardial damage caused by oxidative stress and apoptosis developed by the LPS-induced sepsis model.

Rosiglitazone attenuates amyloid beta and glial fibrillary acidic protein in the hippocampus and neuroinflammation associated learning and memory impairments in rats

OBJECTIVE

The aim of the current study was to investigate the beneficial effects of rosiglitazone (Rosi) on amyloid beta(Aβ) and glial fibrillary acidic protein (GFAP) in the hippocampus and neuroinflammation-associated learning and memory impairments in rats.

MATERIALS AND METHODS

The rats were grouped and treated as follows: (1) Control in which saline and vehicle were administered instead of LPS and Rosi respectively. (2) Lipopolysaccharide (LPS) group in which LPS was dissolved in saline and injected (1 mg/kg) intraperitoneally. Vehicle was administered instead of Rosi in this group. (3-5) LPS+ Rosi 1, LPS+ Rosi 3, and LPS+ Rosi 5 groups in them 1, 3, or 5 mg/kg of Rosi respectively was administered 30 min before LPS. The treatments were done for two weeks. In the first week, Rosi or its vehicle was injected 30 min before LPS. In the second week, the treatments were the same as the first week and behavioral tests were also carried out in the second week. The hippocampal tissues were finally detached for biochemical assessment.

RESULTS

The results showed that Rosi reversed increased levels of Aβ, GFAP, interleukin (IL)- 6, tumor necrosis factor-α (TNF-α), nitric oxide (NO) metabolites, and malondialdehyde (MDA) due to LPS injection. Rosi also reversed attenuating effects of LPS on IL-10 and thiol concentration and activities of catalase (CAT) and superoxide dismutase (SOD). In the Morris water maze test, the LPS group had a longer latency to find the platform while spent a shorter time spent in the target quadrant in the probe trial than the control group. In the passive avoidance test, the animals of the LPS group had a shorter delay to enter the dark chamber than the animals of the control group. Treatment with Rosi reversed these parameters.

CONCLUSION

The findings showed Rosi attenuated Aβ, GFAP, and oxidative stress in the hippocampus and neuroinflammation-associated learning and memory impairments in rats.

Oxidative stress and associated clinical manifestations in malaria and sickle cell (HbSS) comorbidity

In Ghana, uncomplicated malaria and sickle cell disease (SCD) is common, hence comorbidity is not farfetched. However, the extent of oxidative stress and the array of clinical manifestations in this comorbidity (presence of both malaria and SCD) has not been fully explored. This study highlights the impact of uncomplicated malaria on SCD. The level of isoprostane, 8-iso-prostaglandin F2α (8-iso-PGF2α) was used to assess oxidative stress while plasma biochemistry and urinalysis was used to assess renal function. Hematological profiling was also done to assess the impact of comorbidity on the hematological cell lines. Of the 411 study participants with malaria, 45 (11%) had SCD. Mean body temperature was significantly higher in comorbidity compared to malaria and SCD cohorts, while a lower parasite density range was obtained in comorbidity compared to malaria cohorts. Furthermore, in comorbidity, the 8-iso-PGF2α oxidative stress biomarker was significantly elevated in all ages, parasite density ranges and gender groups. Comorbidity affected both leukocytic and erythrocytic cell lines with significant eosinophilia and monocytosis coexisting with erythrocytic parameters consistent with severe anemia. Biochemically, while plasma creatinine and bilirubin were significantly elevated in comorbidity, spot urinary creatinine was significantly reduced. Additionally, urine samples in the comorbid state were slightly acidic and hypersthenuric with significant hematuria, proteinuria, and bilirubinemia. Finally, 80% or more malaria-SCD presented with chills, fever, anorexia, headache, joint pains, lethargy, and vomiting. In conclusion, malaria could induce vaso-occlusive crisis in sickle cell disease, therefore, prompt management will alleviate the severity of this comorbidity.

Potential deleterious effects of paracetamol dose regime used in Nigeria versus that of the United States of America

Paracetamol, also known as acetaminophen (N-acetyl-para-aminophenol, APAP) is the world's most used over-the-counter analgesic-antipyretic drug. Despite its good safety profile, acetaminophen can cause severe hepatotoxicity in overdose, and poisoning from paracetamol has become a major public health concern. Paracetamol is now the major cause of acute liver failure in the United States and Europe. This systematic review aims at examining the likelihood of paracetamol use in Nigeria causing more liver toxicity vis-à-vis the reduced maximum recommended daily adult dose of 3 g for the 500 mg tablet. Online searches were conducted in the databases of PubMed, Google Scholar and MEDLINE for publications using terms like "paracetamol toxicity," "acetaminophen and liver toxicity," "paracetamol and liver diseases in Nigeria," and other variants. Further search of related references in PubMed was carried out, and synthesis of all studies included in this review finalized. There were 94 studies that met the inclusion criteria. Evaluation of hepatic disorder was predicated mostly on a constellation of clinical features and limited clinical laboratory investigations. Determination of blood paracetamol concentration was rarely reported, thus excluding paracetamol poisoning as one of the likely causes of liver disorders in Nigeria. In Nigeria and elsewhere, several factors are known to increase paracetamol's predisposition to liver injury. They include: the over-the-counter status of paracetamol, use of fixed-dose combinations of paracetamol with other drugs, malnutrition, dose miscalculations, and chronic alcohol consumption. The tendency to exceed the new paracetamol maximum daily dose of 3 g in Nigeria may increase its risk for hepatotoxicity than observed in the United States of America known for emphasizing lower dose of the drug. In addition to recommending the new maximal daily paracetamol dose allowance, the historical maximum daily adult dose of 4 g should be de-emphasized in Nigeria.

Effect of Alpha-Lipoic Acid on Rat Ventricles and Atria under LPS-Induced Oxidative Stress

Alpha-lipoic acid (α-LA) is a disulfide compound and one of the most effective antioxidants. Many studies have indicated positive effects of α-LA in the prevention of pathologic conditions mediated by oxidative stress, such as cardiovascular diseases. However, the therapeutic potential of α-LA for the heart has not been explored with regards to the ventricles and atria. The aim of our study was to evaluate the effects of α-LA on oxidative stress parameters and inflammation in the ventricles and atria of the heart in rats under LPS-induced oxidative stress. Wistar rats were divided into 4 groups: I—control (received 2 doses of 0.2 mL of 0.9% NaCl i.v., 0.5 h apart); II—α-LA (received 0.2 mL of 0.9% NaCl and 0.5 h later received α-LA 60 mg/kg b.w. i.v.); III—lipopolysaccharide (LPS) (received 0.2 mL of 0.9% NaCl and 0.5 h later received LPS 30 mg/kg b.w. i.v.); and IV—LPS + LA (received LPS 30 mg/kg b.w. i.v. and 0.5 h later received α-LA 60 mg/kg b.w. i.v.). Five hours later, the rats were euthanized. The hearts were surgically removed and weighed to estimate heart edema. The ventricular and atrium tissue was isolated to measure levels of TNF-α, IL-6, superoxide dismutase (SOD), thiobarbituric acid reactive substances (TBARS), hydrogen peroxide (H₂O₂), total sulfhydryl groups (-SH), total glutathione (tGSH), reduced glutathione (GSH), glutathione disulfide (GSSG), and the GSH/GSSG ratio. LPS significantly increased TNF-α, IL-6, TBARS, and H₂O₂ levels and decreased SOD, -SH groups, tGSH, the GSH/GSSG ratio, and GSH levels in rat ventricles and atria while α-LA administered after the injection of LPS significantly decreased TNF-α, IL-6, TBARS, and H₂O₂ levels. α-LA also increased SOD and -SH group levels and ameliorated the glutathione redox status when compared to the LPS group. Our data suggest that α-LA administration 30 min after LPS infusion may effectively prevent inflammation and oxidative stress in the ventricles and atria.

The innate immune system and fever under redox control: A Narrative Review

ABSTRACT:

In living cells, redox potential is vitally important for normal physiological processes that are closely regulated by antioxidants, free amino acids and proteins that either have reactive oxygen and nitrogen species capture capability or can be compartmentalized. Although hundreds of experiments support the regulatory role of free radicals and their derivatives, several authors continue to claim that these perform only harmful and non-regulatory functions. In this paper we show that countless intracellular and extracellular signal pathways are directly or indirectly linked to regulated redox processes. We also briefly discuss how artificial oxidative stress can have important therapeutic potential and the possible negative effects of popular antioxidant supplements.

Altered microbiota-host metabolic cross talk preceding neutropenic fever in patients with acute leukemia

In 2 cohorts of patients with acute leukemia, Akkermansia expansion in the gut predicted a higher risk for neutropenic fever.

Metabolomics analysis suggested oxidative stress as the mediating pathway, thus offering potential targets for personalized prophylaxis.

Despite antibiotic prophylaxis, most patients with acute leukemia receiving mucotoxic chemotherapy develop neutropenic fever (NF), many cases of which remain without a documented etiology. Antibiotics disrupt the gut microbiota, with adverse clinical consequences, such as Clostridioides difficile infection. A better understanding of NF pathogenesis could inform the development of novel therapeutics without deleterious effects on the microbiota. We hypothesized that metabolites absorbed from the gut to the bloodstream modulate pyrogenic and inflammatory pathways. Longitudinal profiling of the gut microbiota in 2 cohorts of patients with acute leukemia showed that Akkermansia expansion in the gut was associated with an increased risk for NF. As a prototype mucolytic genus, Akkermansia may influence the absorption of luminal metabolites; thus, its association with NF supported our metabolomics hypothesis. Longitudinal profiling of the serum metabolome identified a signature associated with gut Akkermansia and 1 with NF. Importantly, these 2 signatures overlapped in metabolites in the γ-glutamyl cycle, suggesting oxidative stress as a mediator involved in Akkermansia-related NF. In addition, the level of gut microbial–derived indole compounds increased after Akkermansia expansion and decreased before NF, suggesting their role in mediating the anti-inflammatory effects of Akkermansia, as seen predominantly in healthy individuals. These results suggest that Akkermansia regulates microbiota-host metabolic cross talk by modulating the mucosal interface. The clinical context, including factors influencing microbiota composition, determines the type of metabolites absorbed through the gut barrier and their net effect on the host. Our findings identify novel aspects of NF pathogenesis that could be targets for precision therapeutics. This trial was registered at www.clinicaltrials.gov as #NCT03316456.

Characterization of Headache in COVID-19: a Retrospective Multicenter Study

Headache is the most common neurological symptom in COVID-19, reported in 6.5 to 34% of patients. Few studies have analyzed its characteristics, and some of them included cases without laboratory confirmation or reported only critical patients. We aimed to analyze the clinical characteristics of COVID-19 associated headache in laboratory-confirmed cases. We conducted a retrospective evaluation of patients with COVID-19 and neurological symptoms. Patients who reported headache answered an interview about its clinical characteristics. Twenty-four patients with COVID-19 associated headache completed the interview. Mean age of patients was 53.8 (standard deviation—17.44), and 14 out of 24 (58.3%) were male. The majority (75%) had no previous history of headache. Fever was documented in 19 out of the 24 patients (79.1%). Headache was predominantly bifrontal or holocranial, in pressure, during hours, worsening with cough or physical activity. COVID-19 headache tends to appear in the first days of symptoms, be either frontal or holocranial and last for days. The quality of pain in pressure and the worsening with cough or physical activity were reported in most cases. We have not found any characteristic that could differentiate COVID-19 associated headache from other causes of headache, possibly because of its multifactorial mechanism.

Fever and Antipyretic Supported by Traditional Chinese Medicine: A Multi-Pathway Regulation

The coronavirus disease, 2019 (COVID-19), has spread rapidly around the world and become a major public health problem facing the world. Traditional Chinese medicine (TCM) has been fully committed to treat COVID-19 in China. It improved the clinical symptoms of patients and reduced the mortality rate. In light of the fever was identified as one of leading clinical features of COVID-19, this paper will first analyze the material basis of fever, including pyrogenic cytokines and a variety of the mediators of fever. Then the humoral and neural pathways of fever signal transmission will be described. The scattered evidences about fever recorded in recent years are connected in series. On this basis, the understanding of fever is further deepened from the aspects of pathology and physiology. Finally, combining with the chemical composition and pharmacological action of available TCM, we analyzed the mechanisms of TCMs to play the antipyretic effect through multiple ways. So as to further provide the basis for the research of antipyretic compound preparations of TCMs and explore the potential medicines for the prevention and treatment of COVID-19.

Toxicological Property of Acetaminophen: The Dark Side of a Safe Antipyretic/Analgesic Drug?

Acetaminophen (paracetamol, N-acetyl-p-aminophenol; APAP) is the most popular analgesic/antipyretic agent in the world. APAP has been regarded as a safer drug compared with non-steroidal anti-inflammatory drugs (NSAIDs) particularly in terms of lower risks of renal dysfunction, gastrointestinal injury, and asthma/bronchospasm induction, even in high-risk patients such as the elderly, children, and pregnant women. On the other hand, the recent increasing use of APAP has raised concerns about its toxicity. In this article, we review recent pharmacological and toxicological findings about APAP from basic, clinical, and epidemiological studies, including spontaneous drug adverse events reporting system, especially focusing on drug-induced asthma and pre-and post-natal closure of ductus arteriosus. Hepatotoxicity is the greatest fault of APAP and the most frequent cause of drug-induced acute liver failure in Western countries. However, its precise mechanism remains unclear and no effective cure beyond N-acetylcysteine has been developed. Recent animal and cellular studies have demonstrated that some cellular events, such as c-jun N-terminal kinase (JNK) pathway activation, endoplasmic reticulum (ER) stress, and mitochondrial oxidative stress may play important roles in the development of hepatitis. Herein, the molecular mechanisms of APAP hepatotoxicity are summarized. We also discuss the not-so-familiar "dark side" of APAP as an otherwise safe analgesic/antipyretic drug.

COVID-19 is a Real Headache!

After the emergence of a novel coronavirus named SARS‐CoV‐2, coronavirus disease 2019 (COVID‐19) was initially characterized by fever, sore throat, cough, and dyspnea, mainly manifestations of respiratory system. However, other manifestations such as headache, abdominal pain, diarrhea, loss of taste and smell were added to the clinical spectrum, during the course of the COVID‐19 pandemic. The reports on the neurological findings are increasing rapidly and headache seems to be the leader on the symptom list. Headache was reported in 11%‐34% of the hospitalized COVID‐19 patients, but clinical features of these headaches were totally missing in available publications. According to our initial experience, significant features of headache presentation in the symptomatic COVID‐19 patients were new‐onset, moderate‐severe, bilateral headache with pulsating or pressing quality in the temporoparietal, forehead or periorbital region. The most striking features of the headache were sudden to gradual onset and poor response to common analgesics, or high relapse rate, that was limited to the active phase of the COVID‐19. Symptomatic COVID‐19 patients, around 6%‐10%, also reported headache as a presenting symptom. The possible pathophysiological mechanisms of headache include activation of peripheral trigeminal nerve endings by the SARS‐CoV‐2 directly or through the vasculopathy and/or increased circulating pro‐inflammatory cytokines and hypoxia. We concluded that as a common non‐respiratory symptom of COVID‐19, headache should not be overlooked, and its characteristics should be recorded with scrutiny.

Muscle spasm-induced exothermia in dystonic cerebral palsy: uncommon and frequently misdiagnosed condition

A known cerebral palsy young man presented with prolonged bouts of generalised body movements associated with high-grade fever without any localising signs of infection, requiring multiple hospital admissions over several months. All septic work-ups, including a lumbar puncture, were negative. Serum chemistry was consistent with rhabdomyolysis. Repeated electroencephalograms showed no epileptiform discharges. Cranial MRI with gadolinium contrast revealed left cerebral atrophy with hyperintensities at the left basal ganglia. Uncontrolled dystonia with concomitant rhabdomyolysis was considered. Subsequent aggressive hydration and administration of muscle relaxant afforded abrupt resolution of symptoms.

Antioxidant, antibacterial, antidiarrheal and antipyretic activities of organic crude fractions of Commelina paludosa

Background:

The herb, Commelina paludosa (CP) Blume (Family-Commelinaceae) is medicinally used by the traditional practitioners in Bangladesh. However, there is a lack of scientific evidence on this medicinal herb.

Aim and Objectives:

This study aimed to evaluate the phytochemical and pharmacological activities of CP (ethanol [ECP], chloroform [CCP] and n-hexane [NHCP] of whole-plant extracts).

Materials and Methods:

For this antioxidant, antimicrobial, antidiarrheal and antipyretic activities of crude extracts of CP were conducted by 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging, disc diffusion and serial dilution, castor oil-induced diarrhea and yeast powder-induced pyrexia methods respectively.

Results and Observation:

The results suggest that all the fractions significantly scavenged DPPH radicals. In the disc diffusion test, the zones of inhibition were observed within the range of 7 mm to 30.67 mm at 500 mg/disc. The highest zones of inhibition were observed by ECP, CCP and NHCP against Bacillus azotoformans, Lactobacillus coryifomis and Salmonella typhi respectively. NHCP was found to exert stronger antibacterial effect than the ECP and CCP.

Conclusion:

Minimum inhibitory concentrations were detected within the range of 31.25 and 250 μg/ml. Moreover, the crude fractions also showed significant (P < 0.05) antidiarrheal and antipyretic activities in Swiss mice. CP may be a good source of therapeutic components.

Protective effect against brain tissues oxidative damage as a possible mechanism for beneficial effects of L-arginine on lipopolysaccharide induced memory impairment in rats

L-Arginine (LA) and nitric oxide (NO) have been suggested to have some effects on learning, memory, brain tissues oxidative damage, and neuroinflammation. In this study, protective effect against brain tissues oxidative damage as a possible mechanism for beneficial effects of LA on lipopolysaccharide (LPS) induced memory impairment was investigated. The rats were grouped into and treated by (1) control (saline), (2) LPS (1 mg/kg, IP), (3) LA (200 mg/kg) - LPS (4) LA. In passive avoidance (PA) test, LPS administration shortened the latency to enter the dark compartment in LPS group compared to control (p < .001) which was accompanied with a high level of malondialdehyde (MDA) and NO metabolite concentrations in the hippocampal tissues (p < .001and p < .05, respectively). Pretreatment with LA prolonged the latency in LA-LPS group compared with LPS group (p < .01-.001) and re-stored MDA and NO metabolites in the hippocampal tissues (p < .05). LPS also reduced superoxide dismutase (SOD) and catalase (CAT) activities and thiol content in the hippocampal tissues in LPS group compared to control (p < .05 and p < .001, respectively) which improved by LA when it was administered before LPS in LA-LPS group (p < .05 and p < .001). Finally, the serum TNFα level of LPS group was higher than the control (p < .01) while, in LA-LPS group it was lower than LPS group (p < .01). It seems that the beneficial effects of LA on memory impairment of LPS-treated rats may be due to its protective effects against brain tissues oxidative damage.

Acetaminophen from liver to brain: New insights into drug pharmacological action and toxicity

Acetaminophen (APAP) is a well-known analgesic and antipyretic drug. It is considered to be safe when administered within its therapeutic range, but in cases of acute intoxication, hepatotoxicity can occur. APAP overdose is the leading cause of acute liver failure in the northern hemisphere. Historically, studies on APAP toxicity have been focused on liver, with alterations in brain function attributed to secondary effects of acute liver failure. However, in the last decade the pharmacological mechanism of APAP as a cannabinoid system modulator has been documented and some articles have reported "in situ" toxicity by APAP in brain tissue at high doses. Paradoxically, low doses of APAP have been reported to produce the opposite, neuroprotective effects. In this paper we present a comprehensive, up-to-date overview of hepatic toxicity as well as a thorough review of both toxic and beneficial effects of APAP in brain.

Clinical chorioamnionitis at term IV: the maternal plasma cytokine profile

INTRODUCTION

Fever is a major criterion for clinical chorioamnionitis; yet, many patients with intrapartum fever do not have demonstrable intra-amniotic infection. Some cytokines, such as interleukin (IL)-1, IL-6, interferon-gamma (IFN-γ), and tumor necrosis factor alpha (TNF-α), can induce a fever. The objective of this study was to determine whether maternal plasma concentrations of cytokines could be of value in the identification of patients with the diagnosis of clinical chorioamnionitis at term who have microbial-associated intra-amniotic inflammation.

METHODS

A retrospective cross-sectional study was conducted, including patients with clinical chorioamnionitis at term (n=41; cases) and women in spontaneous labor at term without clinical chorioamnionitis (n=77; controls). Women with clinical chorioamnionitis were classified into three groups according to the results of amniotic fluid culture, broad-range polymerase chain reaction coupled with electrospray ionization mass spectrometry (PCR/ESI-MS), and amniotic fluid IL-6 concentration: 1) no intra-amniotic inflammation; 2) intra-amniotic inflammation without detectable microorganisms; or 3) microbial-associated intra-amniotic inflammation. The maternal plasma concentrations of 29 cytokines were determined with sensitive and specific V-PLEX immunoassays. Nonparametric statistical methods were used for analysis, adjusting for a false discovery rate of 5%.

RESULTS

1) The maternal plasma concentrations of pyrogenic cytokines (IL-1β, IL-2, IL-6, IFN-γ, and TNF-α) were significantly higher in patients with clinical chorioamnionitis at term than in those with spontaneous term labor without clinical chorioamnionitis; 2) the maternal plasma concentrations of cytokines were not significantly different among the three subgroups of patients with clinical chorioamnionitis (intra-amniotic inflammation with and without detectable bacteria and those without intra-amniotic inflammation); and 3) among women with the diagnosis of clinical chorioamnionitis, but without evidence of intra-amniotic inflammation, the maternal plasma concentrations of pyrogenic cytokines were significantly higher than in patients with spontaneous labor at term. These observations suggest that a fever can be mediated by increased circulating concentrations of these cytokines, despite the absence of a local intra-amniotic inflammatory response.

CONCLUSIONS

1) The maternal plasma concentrations of pyrogenic cytokines (e.g. IL-1β, IL-2, IL-6, IFN-γ, and TNF-α) are higher in patients with intra-partum fever and the diagnosis of clinical chorioamnionitis at term than in those in spontaneous labor at term without a fever; and 2) maternal plasma cytokine concentrations have limited value in the identification of patients with bacteria in the amniotic cavity. Accurate assessment of the presence of intra-amniotic infection requires amniotic fluid analysis.

The effects of L-arginine on spatial memory and synaptic plasticity impairments induced by lipopolysaccharide

Background:

An important role of nitric oxide (NO) in neuroinflammation has been suggested. It is also suggested that NO has a critical role in learning and memory. Neuro-inflammation induced by lipopolysaccharide (LPS) has been reported that deteriorates learning and memory. The effect of L-arginine (LA) as a precursor of NO on LPS-induced spatial learning and memory and neuronal plasticity impairment was evaluated.

Materials and Methods:

The animals were grouped into: (1) Control, (2) LPS, (3) LA-LPS, and (4) LA. The rats received intraperitoneally LPS (1 mg/kg) 2 h before experiments and LA (200 mg/kg) 30 min before LPS. The animals were examined in Morris water maze (MWM). Long-term potentiation (LTP) from CA₁ area of the hippocampus was also assessed by 100 Hz stimulation in the ipsilateral Schaffer collateral pathway.

Results:

In MWM, time latency and traveled path were higher in LPS group than the control group (P < 0.001) whereas in LA-LPS group they were shorter than LPS group (P < 0.001). The amplitude and slope of field excitatory postsynaptic potential (fEPSP) decreased in LPS group compared to control group (P < 0.05 and P < 0.01) whereas, there was not any significant difference in these parameters between LPS and LA-LPS groups.

Conclusion:

Administration of LPS impaired spatial memory and synaptic plasticity. Although LA ameliorated deleterious effects of LPS on learning of spatial tasks, it could not restore LPS-induced LTP impairment.

Lipopolysaccharide-induced memory impairment in rats is preventable using 7-nitroindazole

Inflammation and oxidative stress have important roles in memory impairment. The effect of 7-nitroindazole (7NI) on lipopolysaccharide (LPS)-induced memory impairment was investigated. Rats were used, divided into four groups that were treated as follows: (1) control (saline); (2) LPS; (3) 7NI-LPS; and (4) 7NI before passive avoidance (PA). In the LPS group, the latency for entering the dark compartment was shorter than in the controls (p < 0.01 and p < 0.001); while in the 7NI-LPS group, it was longer than in the LPS group (p < 0.01 and p < 0.001). Malondialdehyde (MDA) and nitric oxide (NO) metabolite concentrations in the brain tissues of the LPS group were higher than in the controls (p < 0.001 and p < 0.05); while in the 7NI-LPS group, they were lower than in the LPS group (p < 0.001 and p < 0.05, respectively). The thiol content in the brain of the LPS group was lower than in the controls (p < 0.001); while in the 7NI-LPS group, it was higher than in the LPS group (p < 0.001). It is suggested that brain tissue oxidative damage and NO elevation have a role in the deleterious effects of LPS on memory retention that are preventable using 7NI.

Mechanisms of fever production and lysis: lessons from experimental LPS fever

Fever is a cardinal symptom of infectious or inflammatory insults, but it can also arise from noninfectious causes. The fever-inducing agent that has been used most frequently in experimental studies designed to characterize the physiological, immunological and neuroendocrine processes and to identify the neuronal circuits that underlie the manifestation of the febrile response is lipopolysaccharide (LPS). Our knowledge of the mechanisms of fever production and lysis is largely based on this model. Fever is usually initiated in the periphery of the challenged host by the immediate activation of the innate immune system by LPS, specifically of the complement (C) cascade and Toll-like receptors. The first results in the immediate generation of the C component C5a and the subsequent rapid production of prostaglandin E2 (PGE2). The second, occurring after some delay, induces the further production of PGE2 by induction of its synthesizing enzymes and transcription and translation of proinflammatory cytokines. The Kupffer cells (Kc) of the liver seem to be essential for these initial processes. The subsequent transfer of the pyrogenic message from the periphery to the brain is achieved by neuronal and humoral mechanisms. These pathways subserve the genesis of early (neuronal signals) and late (humoral signals) phases of the characteristically biphasic febrile response to LPS. During the course of fever, counterinflammatory factors, "endogenous antipyretics," are elaborated peripherally and centrally to limit fever in strength and duration. The multiple interacting pro- and antipyretic signals and their mechanistic effects that underlie endotoxic fever are the subjects of this review.

Pharmacological Basis for Traditional Use of the Lippia thymoides

The aim of this study was to evaluate crude extracts and fractions from leaves and stems of Lippia thymoides and to validate their use in folk medicine. In vitro antioxidant and antimicrobial activities and in vivo wound healing in rats, baker yeast-induced fever in young rats, and acute oral toxicity in mice assays were realized. The crude extracts and their dichloromethane and ethyl acetate fractions had potent radical-scavenging activity against the DPPH but were not effective in the β-carotene bleaching method. The dichloromethane fraction from the leaves extract showed the broadest spectrum of activity against S. aureus, B. cereus, and C. parapsilosis. The animals treated with crude extracts showed no difference in wound healing when compared with the negative control group. The crude extract from leaves (1200 mg/kg) has equal efficacy in reducing temperature in rats with hyperpyrexia compared to dipyrone (240 mg/kg) and is better than paracetamol (150 mg/kg). In acute toxicity test, crude extract of leaves from Lippia thymoides exhibited no mortality and behavioral changes and no adverse effects in male and female mice. This work validates the popular use of Lippia thymoides for treating the wound and fever, providing a source for biologically active substances.

Modulation of cytochrome P450 2A5 activity by lipopolysaccharide: low-dose effects and non-monotonic dose-response relationship

Mouse cytochrome P450 (CYP) 2A5 is induced by inflammatory conditions and infectious diseases that down-regulate the expression and activity of most other CYP isoforms. Enhanced oxidative stress and nuclear factor (erythroid 2-related factor) 2 (Nrf2) transcription factor activation have been hypothesised to mediate up-regulation of CYP2A5 expression in the murine liver. The unique and complex regulation of CYP2A5, however, is far from being thoroughly elucidated. Sepsis and high doses of bacterial lipopolysaccharide (LPS) elicit oxidative stress in the liver, but depression, not induction, of CYP2A5 has been observed in studies of mice treated with LPS. The foregoing facts prompted us to evaluate the response of CYP2A5 liver activity in female DBA-2 mice over a broad range of LPS doses (0, 0.025, 0.05, 0.1, 0.2, 0.5, 1, 2, 5, 10, and 20 mg/kg). Cytokine levels (interleukin [IL]-2, IL-4, IL-6, IL-10, IL-17A, interferon gamma, tumour necrosis factor alpha) and nitric oxide (NO) were measured in the blood serum. Activities of CYP1A (EROD) and CYP2B (BROD) in the liver were also determined for comparative purposes. LPS depressed CYP2A5 at low doses (0.025–2.0 mg/kg) but not at doses (>2 mg/kg) that increased pro-inflammatory cytokines and NO serum levels, and depressed CYP1A and CYP2B activities. Blockade of pro-inflammatory cytokines and the overproduction of NO induced by co-treatment with pentoxifylline and LPS and iNOS inhibition with aminoguanidine both extended down-regulation of CYP2A5 to the high dose range while not affecting LPS-induced depression of CYP1A and CYP2B. Overall, the results suggested that NO plays a role in the reversal of the low-dose LPS-induced depression of CYP2A5 observed when mice were challenged with higher doses of LPS.

Modulation of cytokine production by drugs with antiepileptic or mood stabilizer properties in anti-CD3- and anti-Cd40-stimulated blood in vitro

Increased cytokine production possibly due to oxidative stress has repeatedly been shown to play a pivotal role in the pathophysiology of epilepsy and bipolar disorder. Recent in vitro and animal studies of valproic acid (VPA) report antioxidative and anti-inflammatory properties, and suppression of interleukin (IL)-6 and tumor necrosis factor (TNF)-α. We tested the effect of drugs with antiepileptic or mood stabilizer properties, namely, primidone (PRM), carbamazepine (CBZ), levetiracetam (LEV), lamotrigine (LTG), VPA, oxcarbazepine (OXC), topiramate (TPM), phenobarbital (PB), and lithium on the production of the following cytokines in vitro: interleukin (IL)-1β, IL-2, IL-4, IL-6, IL-17, IL-22, and TNF-α. We performed a whole blood assay with stimulated blood of 14 healthy female subjects. Anti-human CD3 monoclonal antibody OKT3, combined with 5C3 antibody against CD40, was used as stimulant. We found a significant reduction of IL-1 and IL-2 levels with all tested drugs other than lithium in the CD3/5C3-stimulated blood; VPA led to a decrease in IL-1β, IL-2, IL-4, IL-6, IL-17, and TNF-α production, which substantiates and adds knowledge to current hypotheses on VPA's anti-inflammatory properties.

Tetramethylpyrazine decreases hypothalamic glutamate, hydroxyl radicals and prostaglandin-E2 and has antipyretic effects

OBJECTIVE

We studied the effects of tetramethylpyrazine (TMP) on the fever, increased plasma levels of tumor necrosis factor-α (TNF-α) and increased hypothalamic levels of glutamate, hydroxyl radicals and prostaglandin-E2 (PGE2) induced by lipopolysaccharide (LPS).

MATERIALS AND METHODS

The microdialysis probes were stereotaxically and chronically implanted into the hypothalamus of rabbit brain for determining extracellular levels of glutamate, hydroxyl radials, and PGE2. In addition, both the body core temperature and plasma levels of TNF-α were measured.

RESULTS

All the body core temperature, plasma levels of TNF-α, and hypothalamic levels of glutamate, hydroxyl radicals, and PGE2 were up-graded by an intravenous dose of LPS (2 μg/kg). Pretreatment with intravenous TMP (10-40 mg/kg) or intracerebroventricular TMP (130 μg in 20 μl per animal) 1 h before LPS administration significantly attenuated the LPS-induced fever as well as the increased hypothalamic levels of glutamate, hydroxyl radicals, and PGE2. LPS-induced fever could also be attenuated by intravenous or intracerebroventricular TMP 1 h after LPS injection.

CONCLUSION

TMP preconditioning may cause its antipyretic action by reducing plasma levels of TNF-α as well as hypothalamic levels of glutamate, hydroxyl radicals, and PGE2 in rabbits.