Indirect Anti-inflammatory Effects Research Articles

A New 4-Thiazolidinone Derivative (Les-6490) as a Gut Microbiota Modulator: Antimicrobial and Prebiotic Perspectives.

A novel 4-thiazolidinone derivative Les-6490 (pyrazol-4-thiazolidinone hybrid) was designed, synthesized, and characterized by spectral data. The compound was screened for its antimicrobial activity against some pathogenic bacteria and fungi and showed activity against Staphylococcus and Saccharomyces cerevisiae (the Minimum Inhibitory Concentration (MIC) 820 μM). The compound was studied in the rat adjuvant arthritis model (Freund's Adjuvant) in vivo. Parietal and fecal microbial composition using 16S rRNA metagenome sequences was checked. We employed a range of analytical techniques, including Taxonomic Profiling (Taxa Analysis), Diversity Metrics (Alpha and Beta Diversity Analysis), Multivariate Statistical Methods (Principal Coordinates Analysis, Principal Component Analysis, Non-Metric Multidimensional Scaling), Clustering Analysis (Unweighted Pair-group Method with Arithmetic Mean), and Comparative Statistical Approaches (Community Differences Analysis, Between Group Variation Analysis, Metastat Analysis). The compound significantly impacted an increasing level of anti-inflammatory microorganisms (Blautia, Faecalibacterium prausnitzii, Succivibrionaceae, and Coriobacteriales) relative recovery of fecal microbiota composition. Anti-Treponemal activity in vivo was also noted. The tested compound Les-6490 has potential prebiotic activity with an indirect anti-inflammatory effect.

Novel transdermal curcumin therapeutic preserves endothelial barrier function in a high-dose LPS rat model

Sepsis is a devastating complication of infection and injury that, through widespread endothelial dysfunction, can cause perfusion deficits and multi-organ failure. To address the recognised need for therapeutics targetting the endothelial barrier, a topical formulation (CUR; VASCEPTOR™; Vascarta Inc, Summit, NJ) was developed to transdermally deliver bio-active concentrations of curcumin—an anti-inflammatory and nitric oxide promoter. Male, Sprague Dawley rats were treated daily with lipopolysaccharide (LPS, 10 mg/kg, IP) to induce endotoxemia, and topical applications of Vehicle Control (LPS + VC; N = 7) or Curcumin (LPS + CUR; N = 7). A third group received neither LPS nor treatment (No-LPS; N = 8). After 72 h, animals were surgically prepared for measurements of physiology and endothelial dysfunction in the exteriorised spinotrapezius muscle through the extravasation of 67 kDa TRITC-BSA (albumin) and 500 kDa FITC-dextran (dextran). At 72 h, LPS + VC saw weight loss, and increases to pulse pressure, lactate, pCO2, CXCL5 (vs No-LPS) and IL-6 (vs 0 h; p < 0.05). LPS + CUR was similar to No-LPS, but with hypotension. Phenylephrine response was increased in LPS + CUR. Regarding endothelial function, LPS + CUR albumin and dextran extravasation were significantly reduced versus LPS + VC suggesting that Curcumin mitigated endotoxemic endothelial dysfunction. The speculated mechanisms are nitric oxide modulation of the endothelium and/or an indirect anti-inflammatory effect.

Evaluation of the Anti-Inflammatory Activity of Enzymatic Hydrolysis Peptide SEP-3 from Skipjack (Katsuwonus pelamis) Based on NF-κB and MAPK Pathways

ABSTRACT The skipjack enzymatic peptide 3 (SEP-3) has been previously isolated and purified from a byproduct of skipjack. In this paper, the anti-inflammatory activity and mechanism of SEP-3 in RAW264.7 macrophages activated by lipopolysaccharide (LPS) were investigated. We found that SEP-3 enhanced the proliferation and phagocytic capacity of RAW264.7 macrophages and suppressed the expression of pro-inflammatory cytokines IL-1β, IL-6, and TNF-α. Cells treated with SEP-3 showed decreased phosphorylation of ERK, p38, JNK, NF-κB p65, and IκBα and inhibited NF-κB and mitogen-activated protein kinases (MAPK) inflammatory pathways. Optimal dosage was determined, and modified outcome was identified when SEP-3 treatment was combined with indomethacin. In addition, the metabolites of the dominant microflora of mice gavaged by SEP-3 showed antioxidant activity in vitro. Therefore, we conclude that SEP-3 extracted from skipjack may have a direct or indirect anti-inflammatory effect and can be used as an adjuvant drug to treat inflammatory diseases.

Vasoinhibin is Generated and Promotes Inflammation in Mild Antigen-induced Arthritis.

Inflammatory arthritis defines a family of diseases influenced by reproductive hormones. Vasoinhibin, a fragment of the hormone prolactin (PRL), has antiangiogenic and proinflammatory properties. We recently showed that vasoinhibin reduces joint inflammation and bone loss in severe antigen-induced arthritis (AIA) by an indirect mechanism involving the inhibition of pannus vascularization. This unexpected finding led us to hypothesize that a severe level of inflammation in AIA obscured the direct proinflammatory action of vasoinhibin while allowing the indirect anti-inflammatory effect via its antiangiogenic properties. In agreement with this hypothesis, here we show that the intra-articular injection of an adeno-associated virus type-2 vector encoding vasoinhibin reduced joint inflammation in a severe AIA condition, but elevated joint inflammation in a mild AIA model. The proinflammatory effect, unmasked in mild AIA, resulted in joint swelling, enhanced leukocyte infiltration, and upregulation of expression of genes encoding proinflammatory mediators (Il1b, Il6, Inos, Mmp3), adhesion molecule (Icam1), and chemokines (Cxcl1, Cxcl2, Cxcl3, Ccl2). Furthermore, vasoinhibin induced the expression of proinflammatory mediators and chemokines in cultured synovial fibroblasts through nuclear factor-κB. Finally, matrix metalloproteases and cathepsin D, upregulated in the arthritic joint, cleaved PRL to vasoinhibin, and vasoinhibin levels increased in the circulation of mice subjected to AIA. We suggest that vasoinhibin is generated during inflammatory arthritis and acts on synovial fibroblasts and endothelial cells to initially promote and later inhibit inflammation, respectively. These opposite effects may work together to help keep joint inflammation under balance.

Effects of dipyridamole and its use in neurology

Dipyridamole has been on the pharmaceutical market since 1959 and, as a pyrimidyl-pyrimidine compound, has a variety of mechanisms of action. The very first action of dipyridamole was its antianginal effect. In subsequent years, attention was drawn to the antiplatelet properties of dipyridamole, which are related to inhibition of platelet phosphodiesterase as well as to blocking adenosine transport. Another important property of dipyridamole is its effect on the deformability of red blood cells, thereby improving microcirculation. Dipyridamole affects changes in the dynamics of platelet activity and vascular reactivity and causes improvement of cerebral perfusion. Due to its pronounced antiplatelet properties, the drug has been widely studied for the prevention of ischemic strokes and transient ischemic attacks, both as monotherapy and in combination with other drugs. Unlike other platelet antiaggregants, dipyridamole does not have a damaging effect on mucous membranes. Its antiplatelet effect is not accompanied with inhibition of cyclooxygenase activity and reduction of prostacyclin synthesis. In the treatment of cerebral circulation disorders, dipyridamole can be used to control the antithrombotic effect by selecting the optimal dose of the drug. Dipyridamole has antioxidant properties, enhances NO-mediated pathways, has indirect anti-inflammatory effects via adenosine and prostaglandin-2 as well as direct anti-inflammatory effects and several other effects. Dipyridamole is considered a safe drug based on decades of clinical experience. Its side effects are usually limited and transient. Given the diverse effects of dipyridamole, it can be used for a wide range of pathologies other than thrombosis prevention. Data on the efficacy and safety of dipyridamole in various diseases of the neurological spectrum are presented.

Vitamin D Effects on Guided Bone Regeneration and Osseointegration of Dental Implants (Literature Review)

Background.Due to the prevalence of Vitamin D deficiency as well as the frequency of reconstructive surgical interventions followed by dental implantation, the issue arises concerning the effect of Vitamin D on reparative regeneration of bone and osseointegration of dental implants.The purpose using literature data we are conducting an impact assessment of vitamin D on reparative regeneration of bone tissue, in particular, after oral reconstruction surgeries and dental implantation.Methods.Retrieval, systematization and analysis of scientific data on application of vitamin D supplementation and its effect on reparative regeneration of jaw bone tissue.The conclusions.For the most part, the positive effect exerted on reparative regeneration of jaw bone tissue and osseointegration of dental implants is due to the role of vitamin D in physiological processes evolving in bone tissue, namely maintenance of calcium and phosphate exchange through intestinal absorption and TNF, RANKL (Receptor activator of nuclear factor kappa-B ligand) and consequently differentiation of precursors to osteoclasts into osteoclasts through VDR stimulation (VitaminD Receptor) receptors for further osteogenesis. Also, according to literature data, FGF23 (Fibroblast Growth Factor) protein is a marker of osteoblasts differentiation into osteocytes, it is also known that FGF23 and 1,25(ОН)2D3 are genetically related. FGF23 is the main regulator of both phosphate exchange in bones and metabolism of vitamin D and its metabolites. Besides, indirect anti-inflammatory effect has been observed thanks to inhibition of pro-inflammatory cytokine secretion. Taking into account the abovementioned data, of particular relevance is the definition of serum concentration 25(ОН)D and development of schemes of vitamin D level pre-surgery correction in patients, who have to undergo oral reconstruction surgeries and dental implantation. Mass spectrometry is a promising diagnostic method for determining the level of vitamin D in a body, as it allows to identify the actual amount of vitamin D free from admixture of other steroid hormones. The introduction of this method into clinical practice will allow to monitor the level of vitamin D in patients, receiving reconstructive and rehabilitative treatment.

Regulatory effects of Ganoderma atrum polysaccharides on LPS-induced inflammatory macrophages model and intestinal-like Caco-2/macrophages co-culture inflammation model

Lipopolysaccharide (LPS)-induced inflammatory macrophages model and intestinal-like Caco-2/macrophages co-culture inflammation model were established to evaluate the anti-inflammatory effect and underlying mechanism of Ganoderma atrum polysaccharides (PSG-1). It was found that PSG-1 reduced LPS-induced secretion of pro-inflammatory cytokine (TNF-α, IL-6 and IL-1β), ROS levels, and inhibited the expression of COX-2 in LPS-stimulated inflammatory macrophages model and intestinal-like Caco-2/macrophages co-culture inflammation model. Furthermore, PSG-1 suppressed the LPS-induced activation of MAPKs signaling pathways, and regulated oxidative stress by activating the Nrf2/Keap1 signaling pathways. These above results indicated that PSG-1 not only has a direct anti-inflammatory effect in LPS-induced inflammatory macrophages model, but also has an indirect anti-inflammatory effect in intestinal-like Caco-2/macrophages co-culture inflammation model. These findings provide new insight of the mechanism underlying the anti-inflammatory activities of PSG-1, and facilitated the expansion of the application of PSG-1 in natural functional food.

Hyperbaric oxygen treatment: A complementary treatment modality of Modic changes?

Modic changes (MCs) have attracted great interest in recent years. The complex process of MC development and progression seems to involve interplay between mechanical, infective, inflammatory, and degenerative processes that cannot be clearly differentiated. Based on signal intensity on T1- and T2-weighted MRI scans, MCs can be divided three types: Type 1, Type 2, and Type 3. Predominantly Type 1 MCs are commonly associated with chronic low back pain that is unresponsive to classic treatment options. Infection with low-virulent anaerobic microorganisms, most commonly Propionibacterium acnes, has been implicated in MC development following a disc herniation when a tear enables bacteria to enter the disc. Recent studies in patients with chronic low back pain following a lumbar disc herniation associated with Type 1 MCs have reported promising results following prolonged systemic antibiotic treatment with amoxicillin-clavulanate. Hyperbaric oxygen therapy, as primary or adjuvant treatment in association combination with systemic antibiotics or anti-inflammatory therapy, could offer important advantages in treating patients with suspected low-virulent disc infections due to anaerobic microorganisms associated with Type 1 MCs. We believe that hyperbaric oxygenation could contribute to faster resolution of Type 1 MCs and associated pain through multiple effects—including direct antimicrobial effects through formation of reactive oxygen species (ROS), altering the favorable low oxygen tension milieu such that it becomes unfavorable for bacterial growth and survival, and anti-biofilm effects. Additionally, hyperbaric oxygenation could contribute to faster pain resolution via direct and indirect anti-inflammatory effects. As an adjuvant treatment administered in combination with systemic antibiotics, HBOT could increase the sensitivity of Propionibacterium acnes to antimicrobial drugs under hyperoxic conditions, resulting in faster MC resolution. Overall, the faster infection resolution, diminished bacterial load, and anti-inflammatory effects due to reduced cytokine expression and levels of infectious by-products could lead to faster pain resolution following HBOT, and a significant improvement of quality of life in these patients.

SARS-CoV-2 (COVID-19) as a predictor of neuroinflammation and neurodegeneration: potential therapy strategies

The pandemic caused by the SARS-CoV-2 virus (COVID-19) made it necessary to evaluate in more detail the processes of neuroinflammation as an integral component of the pathogenesis of viral infection. The acute neuroinflammatory response includes the activation of resident tissue macrophages in the CNS and the subsequent release of various cytokines and chemokines, which probably activates oxidative stress, causing long-term neuronal damage. This makes urgent the search for drugs with indirect anti-inflammatory effects with proven effectiveness. From this point of view, it is worth further studying the treatment of patients with COVID-19 with dipyridamole, which, with its antiviral activity and anti-inflammatory effect, inhibiting acute inflammation and progressive fibrosis, is the drug of choice, especially for patients with early signs of elevated D-dimer concentrations and pronounced clinical symptoms of microangiopathy.

Inhaled medications in cystic fibrosis beyond antibiotics.

Structural lung disease begins very early in children with cystic fibrosis (CF), often in the first three months of life. Inhaled medications represent an attractive therapeutic approach in CF that are routinely used as early intervention strategies. Two aerosolized solutions, hypertonic saline and dornase alfa, have significant potential benefits by improving mucociliary clearance, with minimal associated side-effects. In particular, they favor rehydration of airway surface liquid and cleavage of extracellular DNA in the airways, respectively, consequently reducing rate of pulmonary disease exacerbations. Indirect anti-inflammatory effects have been documented for both drugs, addressing each of the three interrelated elements in the vicious cycle of lung disease in CF: airway obstruction, inflammation and infection. This short review aimed to summarize the main papers that support potential clinical impact of inhaled solutions on pulmonary disease in CF.

Modulation of sphingosine-1-phosphate receptor by FTY720 contributes in improvement of hepatic encephalopathy induced by bile duct ligation

Hepatic encephalopathy (HE) is a complex neuropsychiatric disorder, which is associated with memory loss and behavioral abnormalities. The cellular and molecular mechanisms that led to hippocampal dysfunction in bile duct ligation (BDL)-induced HE and neuroprotective mechanisms of FTY720 administration were evaluated using whole-cell patch clamp, field-potential recording, western blot, stereology and behavioral experiments. The animals were divided into 4 groups of control (n = 24), sham (n = 21), BDL + V (n = 21) and BDL + FTY720 (n = 20), each having three subgroups. The first subgroup was used for field potential, western blot and stereology experiments. The second and third subgroups were used for behavioral experiments and whole cell patch clamp recording, respectively.The BDL led to considerable loss of hippocampal neurons and apoptosis, along with large impairments in their intrinsic electrophysiological properties, including decrease of firing frequency and increases of first spike latency (FSL), AHP amplitude, irregularity of firing, and half-width, as well as impaired long-term synaptic plasticity and memory. Importantly, FTY720 decreased AHP amplitude probably by direct inhibition of Ca2+ channels and/or KCa2+ currents and improved the FSL and firing irregularity and frequency possibly by decreasing A-type K+ currents in the BDL + FTY720 group. FTY720 administration in the BDL rats also decreased the release probability, which was evident by the increased paired-pulse ratio, but the increased number of readily releasable pool (RRP) of neurotransmitter. Moreover, the AHP improvement and RRP increment most likely led to recovery of LTP and memory performance. In total, FTY720 ameliorated brain disorders in the BDL rats via its direct neuroprotective and/or indirect anti-inflammatory effects.

Glucocorticoids exert differential effects on the endothelium in an invitro model of the blood-retinal barrier.

Glucocorticoids (GCs) are used as treatment in diabetic macular oedema, a condition caused by blood-retinal barrier (BRB) disruption. The proposed mechanisms by which GCs reduce macular oedema are indirect anti-inflammatory effects and inhibition of VEGF production, but direct effects on the BRB endothelium may be equally important. Here, we investigated direct effects of GCs on the endothelium to understand the specific pathways of GC action, to enable development of novel therapeutics lacking the adverse side-effects of the presently used GCs. Primary bovine retinal endothelial cells (BRECs) were grown on Transwell inserts and treated with hydrocortisone (HC), dexamethasone (Dex) or triamcinolone acetonide (TA). Molecular barrier integrity of the BRB was determined by mRNA and protein expression, and barrier function was assessed using permeability assays. In addition, we investigated whether TA was able to prevent barrier disruption after stimulation with VEGF or cytokines. Treatment of BRECs with GCs resulted in upregulation of tight junction mRNA (claudin-5, occludin, ZO-1) and protein (claudin-5 and ZO-1). In functional assays, only TA strengthened the barrier function by reducing endothelial permeability. Moreover, TA was able to prevent cytokine-induced permeability in human retinal endothelial cells and VEGF-induced expression of plasmalemma vesicle-associated protein (PLVAP), a key player in VEGF-induced retinal vascular leakage. Glucocorticoids have differential effects in an experimental invitro BRB model. TA is the most potent in improving barrier function, both at the molecular and functional levels, and TA prevents VEGF-induced expression of PLVAP.

Anti-inflammatory effects of exercise: role in diabetes and cardiovascular disease.

Persistent inflammation is involved in the pathogenesis of chronic diseases such as type 2 diabetes mellitus (T2DM) and cardiovascular disease (CVD). The aim of this review was to provide the reader with an update of the mechanisms whereby exercise-induced cytokines may impact cardiometabolic diseases. Evidence exists that interleukin (IL)-1β is involved in pancreatic β-cell damage, whereas TNF-α is a key molecule in peripheral insulin resistance. In addition, TNF-α appears to be involved in the pathogenesis of atherosclerosis and heart failure. A marked increase in IL-6 and IL-10 is provoked by exercise and exerts direct anti-inflammatory effects by an inhibition of TNF-α and by stimulating IL-1ra, thereby limiting IL-1β signalling. Moreover, muscle-derived IL-6 appears to have direct anti-inflammatory effects and serves as a mechanism to improve glucose tolerance. In addition, indirect anti-inflammatory effects of long-term exercise are mediated via improvements in body composition. Physical activity represents a natural, strong anti-inflammatory strategy with minor side effects and should be integrated in the management of patients with cardiometabolic diseases.

Therapeutic approaches targeting inflammation for diabetes and associated cardiovascular risk.

Obesity-related sub-acute chronic inflammation has been associated with incident type 2 diabetes and atherosclerotic cardiovascular disease. Inflammation is increasingly considered to be a pathologic mediator of these commonly co-occurring diseases. A growing number of preclinical and clinical studies support the inflammatory hypothesis, but clinical trials to confirm the therapeutic potential to target inflammation to treat or prevent cardiometabolic conditions are still ongoing. There are multiple inflammatory signaling pathways. Regulation is complex, with substantial crosstalk across these multiple pathways. The activity of select pathways may be differentially regulated in different tissues. Pharmacologic approaches to diabetes management may have direct or indirect antiinflammatory effects, the latter potentially attributable to an improved metabolic state. Conversely, some antiinflammatory approaches may affect glucose metabolism and cardiovascular health. To date, clinical trials suggest that targeting one portion of the inflammatory cascade may differentially affect dysglycemia and atherothrombosis. Understanding the underlying biological processes may contribute to the development of safe and effective therapies, although a single approach may not be sufficient for optimal management of both metabolic and athrothrombotic disease states.

Exercise and type 2 diabetes: focus on metabolism and inflammation.

Type 2 diabetes mellitus (T2DM) is associated with metabolic dysregulation and chronic inflammation, and regular exercise may provide a strong stimulus for improving both. In this review, we first discuss the link between inflammation and metabolism. Next, we give an update on the clinical metabolic effects of exercise in T2DM patients with special focus on which parameters to consider for optimizing metabolic improvements. We then discuss the mechanisms whereby exercise exerts its anti-inflammatory and related metabolic effects. Evidence exists that interleukin (IL)-1β is involved in pancreatic β-cell damage, whereas tumor necrosis factor (TNF)-α appears to be a key molecule in peripheral insulin resistance. Mechanistic studies in humans suggest that moderate acute elevations in IL-6, as provoked by exercise, exert direct anti-inflammatory effects by an inhibition of TNF-α and by stimulating IL-1ra (IL-1 receptor antagonist), thereby limiting IL-1β signaling. In addition, IL-6 has direct impact on glucose and lipid metabolism. Moreover, indirect anti-inflammatory effects of exercise may be mediated via improvements in, for example, body composition. While waiting for the outcome of long-term randomized clinical training studies with hard end points, it should be emphasized that physical activity represents a natural strong anti-inflammatory and metabolism-improving strategy with minor side effects.

Exercise as an anti-inflammatory therapy for rheumatic diseases-myokine regulation.

Persistent systemic inflammation, a typical feature of inflammatory rheumatic diseases, is associated with a high cardiovascular risk and predisposes to metabolic disorders and muscle wasting. These disorders can lead to disability and decreased physical activity, exacerbating inflammation and the development of a network of chronic diseases, thus establishing a 'vicious cycle' of chronic inflammation. During the past two decades, advances in research have shed light on the role of exercise as a therapy for rheumatic diseases. One of the most important of these advances is the discovery that skeletal muscle communicates with other organs by secreting proteins called myokines. Some myokines are thought to induce anti-inflammatory responses with each bout of exercise and mediate long-term exercise-induced improvements in cardiovascular risk factors, having an indirect anti-inflammatory effect. Therefore, contrary to fears that physical activity might aggravate inflammatory pathways, exercise is now believed to be a potential treatment for patients with rheumatic diseases. In this Review, we discuss how exercise disrupts the vicious cycle of chronic inflammation directly, after each bout of exercise, and indirectly, by improving comorbidities and cardiovascular risk factors. We also discuss the mechanisms by which some myokines have anti-inflammatory functions in inflammatory rheumatic diseases.

Direct and Indirect Anti-Inflammatory Effects of Tulathromycin in Bovine Macrophages: Inhibition of CXCL-8 Secretion, Induction of Apoptosis, and Promotion of Efferocytosis

Recent evidence indicates that immunomodulation by antibiotics may enhance their clinical efficacy. Specifically, drug-induced leukocyte apoptosis and macrophage efferocytosis have been shown to promote the resolution of inflammation in a variety of disease settings. Tulathromycin is a new macrolide antibiotic for the treatment of bovine respiratory disease. The direct antimicrobial effects of the drug alone do not fully justify its superior clinical efficacy, and we hypothesize that tulathromycin may have immunomodulating properties. We recently reported that tulathromycin promotes apoptosis and inhibits proinflammatory NF-κB signaling in bovine neutrophils. In this study, we investigated the direct and indirect anti-inflammatory effects of tulathromycin in bovine macrophages. The findings indicate that bovine monocyte-derived macrophages and alveolar macrophages readily phagocytose tulathromycin-induced apoptotic neutrophils both in vitro and in the airways of Mannheimia haemolytica-infected calves. Moreover, tulathromycin promotes delayed, concentration-dependent apoptosis, but not necrosis, in bovine macrophages in vitro. Activation of caspase-3 and detection of mono- and oligonucleosomes in bovine monocyte-derived macrophages treated with tulathromycin was observed 12 h posttreatment; pretreatment with a pan-caspase inhibitor (ZVAD) blocked the proapoptotic effects of the drug. Lastly, tulathromycin inhibited the secretion of proinflammatory CXCL-8 in lipopolysaccharide (LPS)-stimulated bovine macrophages; this effect was independent of caspase activation or programmed cell death. Taken together, these immunomodulating effects observed in bovine macrophages help further elucidate the mechanisms through which tulathromycin confers anti-inflammatory and proresolution benefits. Furthermore, these findings offer novel insights on how antibiotics may offer anti-inflammatory benefits by modulating macrophage-mediated events that play a key role in inflammation.

Neuroprotection by Minocycline Caused by Direct and Specific Scavenging of Peroxynitrite

Minocycline prevents oxidative protein modifications and damage in disease models associated with inflammatory glial activation and oxidative stress. Although the drug has been assumed to act by preventing the up-regulation of proinflammatory enzymes, we probed here its direct chemical interaction with reactive oxygen species. The antibiotic did not react with superoxide or (•)NO radicals, but peroxynitrite (PON) was scavenged in the range of ∼1 μm minocycline and below. The interaction of pharmacologically relevant minocycline concentrations with PON was corroborated in several assay systems and significantly exceeded the efficacy of other antibiotics. Minocycline was degraded during the reaction with PON, and the resultant products lacked antioxidant properties. The antioxidant activity of minocycline extended to cellular systems, because it prevented neuronal mitochondrial DNA damage and glutathione depletion. Maintenance of neuronal viability under PON stress was shown to be solely dependent on direct chemical scavenging by minocycline. We chose α-synuclein (ASYN), known from Parkinsonian pathology as a biologically relevant target in chemical and cellular nitration reactions. Submicromolar concentrations of minocycline prevented tyrosine nitration of ASYN by PON. Mass spectrometric analysis revealed that minocycline impeded nitrations more effectively than methionine oxidations and dimerizations of ASYN, which are secondary reactions under PON stress. Thus, PON scavenging at low concentrations is a novel feature of minocycline and may help to explain its pharmacological activity.

Antinociceptive effects of the essential oil of Mentha x villosa leaf and its major constituent piperitenone oxide in mice

Mentha x villosa Huds (Labiatae) is an aromatic herb widely used in folk medicine. Since the essential oil of the herb has many pharmacological activities, including antispasmodic effects, we determined whether the oil and its major constituent, piperitenone oxide (PO), have antinociceptive activity. The essential oil of M. x villosa (EOMV) and PO administered orally at 200 mg/kg (vehicle: 0.1% Tween 80 in water) significantly reduced the writhings induced by acetic acid from control values of 59.5 +/- 3.1 s (N = 10) to 31.9 +/- 2.8 s (N = 10) and 23.8 +/- 3.4 s (N = 10), respectively. When administered at 100 and 200 mg/kg, EOMV reduced the paw licking time for the second phase of the formalin test from the control value of 20.6 +/- 2.1 s (N = 13) to 5.3 +/- 2.2 s (N = 12) and 2.7 +/- 1.2 s (N = 18), respectively. At 100 and 200 mg/kg, PO reduced this second phase to 8.3 +/- 2.7 s (N = 12) and 3.0 +/- 1.2 s (N = 10), respectively. This effect of EOMV and PO was not reversed by naloxone. EOMV and PO had no significant effect on the first phase of the formalin test. As evaluated by the hot-plate and tail immersion test, EOMV and PO, at doses up to 200 mg/kg, showed no analgesic activity. These results show that EOMV and PO have antinociceptive activity and suggest that this effect is probably an indirect anti-inflammatory effect, which does not involve the central nervous system.

Macrolide antibiotics like azithromycin increase lipopolysaccharide-induced IL-8 production by human gingival fibroblasts

ObjectiveMacrolide antibiotics are reported to modulate the production of cytokines in various type of cells. We examined the effect of macrolide antibiotics on inflammatory cytokines (IL-6 and IL-8) and chemical mediator (PGE2) and also matrix metalloproteinases (MMPs) productions by human gingival fibroblasts (HGFs) treated with lipopolysaccharide (LPS).MethodsThe effect of macrolide antibiotics [erythromycin (EM), azithromycin (AZM) and josamycin (JOM)] on HGFs proliferation were examined by MTT assay. HGFs were treated with LPS from Porphyromonas gingivalis (PgLPS) and macrolide antibiotics, and IL-6, IL-8 and PGE2 levels were evaluated by ELISA. MMPs were detected by gelatin zymography.ResultsAZM slightly but significantly decreased HGFs proliferation, while EM and JOM did not affected. AZM increased PgLPS-induced IL-8 production dose-dependently, while AZM did not alter IL-6 and PGE2 productions. EM and JOM did not altered PgLPS-induced IL-6, IL-8 and PGE2 productions. All macrolide antibiotics did not alter MMPs production. These results indicate that macrolide antibiotics have no direct anti-inflammatory effect. However, the use of the inhibitors of cell signaling pathway failed to reveal the mechanism that AZM enhanced PgLPS-induced IL-8 production.ConclusionThese results suggest macrolide antibiotics have an indirect anti-inflammatory effect as a result of their antimicrobial properties. Because AZM increased LPS-induced IL-8 production by HGFs, the possibility is considered that neutrophils may be migrated to periodontal tissue and phagocytize the periodontopathic bacteria more efficiently.