Effect of fungal indoor air pollutant 1-octen-3-ol on levels of reactive oxygen species and nitric oxide as well as dehydrogenases activities in drosophila melanogaster males

Research has revealed that reactive oxygen species (ROS) negatively affect sperm function, both in vivo and in vitro. Sperm preparation techniques for assisted reproductive technologies (ART) are potential causes for additional ROS production. This study aimed to correlate the concentration of exogenous H(2)O(2) with sperm motility parameters and intracellular ROS and nitric oxide (NO) levels to reiterate the importance of minimising ROS levels in ART. Human spermatozoa from 10 donors were incubated and exposed to different exogenous H(2)O(2) concentrations (0, 2.5, 7.5 and 15 mum). Subsequently, motility was determined using computer-aided semen analysis, while ROS (2,7-dichlorofluorescin diacetate) and NO (diaminofluorescein-2/diacetate) were analysed using fluorescence-activated cell sorting. Results showed that H(2)O(2) did affect the sperm parameters. Exogenous H(2)O(2) was detrimental to motility and resulted in a significant increase in overall ROS and NO levels. A significant increase in static cells was seen as well. It is important to elucidate the mechanisms between intracellular ROS levels with sperm motility parameters. While this experiment demonstrated a need to reduce exogenous ROS levels during ART, it did not illustrate the cause and effect relationship of intracellular ROS and NO levels with sperm motility. Further research needs to be conducted to define a pathological level of ROS.

Leukemic cells often show high nitric oxide (NO) and reactive oxygen species (ROS) levels. These can lead to resistance to apoptosis and therapy and increased proliferation. Plant-derived extracts decrease chemoresistance in cancer cells. In this study, we evaluated the effects of the plant-derived extracts P2Et (Caesalpinia spinosa) and Anamu-SC (Petiveria alliacea) and their combination with chemotherapeutic agents on NO and ROS levels in leukemic cell lines K562 and Reh. NO and ROS were determined using the DAF-FM DA and H2DCFDA probes. The mean fluorescence intensity for each variable was measured by flow cytometry. The extracts showed an antioxidant effect on both cell lines leading to a significant decrease in ROS levels without decreasing cell viability. Anamu-SC also increased NO levels in K562 cells when combined with idarubicin. Both extracts reduced the number of leukemic cells after 12 hours of treatment. Further studies are necessary to evaluate their effect on primary human leukemia cells. These findings suggest the potential of P2Et and Anamu-SC as adjuncts in leukemia treatment.

In colorectal cancers, the local cytokine network and the levels of nitric oxide (NO) and reactive oxygen species (ROS) are known to be closely related to cancer progression and metastasis, but the influence of the currently administered therapies on the cancer microenvironment is not completely understood. We analyzed the levels of reactive oxygen species (ROS), nitric oxide (NO), and cachexia-mediated cytokines (IL-1beta, IL-6, TNF-alpha) in cocultures of human colon carcinoma spheroids prepared with cells derived from tumors of different grades with human normal colon epithelial and myofibroblast cells and normal endothelial cells. We also analyzed the influence of standard chemotherapy with 5-fluorouracil (5-FU) and leucovorin (LV) combined with camptothecin (CPT-11) (IFL regimen with drug concentrations adjusted to in vitro conditions) on these parameters. The results indicated that adhesion of colon carcinoma spheroids to colon epithelium and myofibroblast monolayers induced O2- anion production but decreased NO levels compared to the sum of the radicals released by monocultures of the two types of cells. Coculture of colon carcinoma spheroids with endothelium was an exception to this rule, as only HT29 cells decreased NO production. In cocultures, anticancer drugs additionally, though only slightly and insignificantly, increased the production of the radicals compared to a nontreated coculture, but in monocultures, the drugs, and especially CPT-11, were ROS inducers and simultaneously NO production inhibitors. However, the levels of released ROS and NO were dependent on the stage of colon carcinoma that the cells were derived from. LS180 cells (grade B) grown in monocultures produced the lowest ROS levels but were the best producers of NO. Adhesion of tumor spheroids to normal cells influenced the microenvironmental cytokine network compared to monocultures, decreasing IL-1beta and TNF-alpha secretion but significantly enhancing L-6 levels. The addition of the drugs had no effect on IL-1beta levels but increased TNF-alpha production and lowered the amounts of IL-6. In conclusion, cytotoxic drugs may, dependent on the stage of tumor growth or the type of chemotherapy regimen administered, significantly influence the proinflammatory cytokine network and local ROS and NO levels. Moreover, in cocultures of tumor cells with normal epithelial, myofibroblast, and endothelial cells, ROS production seems to be involved in local cell injury, which was detected by confocal microscopy. On the other hand, high level of NO seems to facilitate tumor cell interactions with the endothelium and metastasis as NO production was the highest in a monoculture of HUVEC and remained at high levels in cocultures of colon cancer cells with HUVEC. Among the proinflammatory cytokines, only IL-6 seems to significantly influence colon carcinoma development and metastasis. Attenuation of IL-6 production after chemotherapy can be a useful prognostic factor of its effectiveness.

Background: Preeclampsia is a disease with a variety of theories that describe the uncertainty of the pathophysiology. According to the oxidative stress theory, preeclampsia originates from the failure of trophoblast invasion during the implantation process, causing ischemia and placental hypoxia, which in turn causes cell damage, including placental endothelial cell dysfunction. Omega-3 fatty acids and vitamin E have an important role in preventing preeclampsia. Omega-3 fatty acids play an important role in maintaining cell membranes and anti-inflammatory processes. At the same time, vitamin E acts as a fat-soluble antioxidant that can prevent oxidative stress, inhibit proinflammatory cytokines, and protect fatty acids from oxidation. Aim: The purpose of this study was to determine the effect of omega-3 and vitamin E on the level of ROS and NO in pregnant rats with preeclampsia models. Method & Material: This type of research is experimental with Post-Test Only Control Group Design. The sample consisted of 35 pregnant rats, which were divided into five groups. On the 19th day, blood serum was taken to check the levels of ROS and NO. The measuring instrument used is a spectrophotometer with the ELISA method. Data were analyzed using the Shapiro Wilks normality test. After the parametric test was completed, the hypothesis was tested using one-way ANOVA. Results: The average levels of ROS in each group were K- : 121,684 ng/L, K+ : 143,885 ng/L, P1 : 136,250 ng/L, P2 : 132.433 ng/L, and P3 : 122,993 ng/L. The average levels of NO obtained were K-: 29,502 ng/L, K+: 26,053 ng/L, P1: 27,250 ng/L, P2: 27,555 ng/L, and P3: 32,278 ng/L. The results of one-way ANOVA analysis showed that the administration of omega-3 and vitamin E had a significant difference between the control and treatment groups, both at levels of ROS (p=0.001) and levels of NO (p=0.001). Conclusion: The administration of omega-3, vitamin E, and omega-3 plus vitamin E can reduce ROS levels in pregnant rats with preeclampsia models. There is an increase of NO levels only in the administration of omega-3 plus vitamin E. Keywords: [Omega-3, Vitamin E, Oxidative stress, ROS, NO, Preeclampsia].

Objective To investigate the effect and mechanism of metformin on endothelial cell damages induced by intermittent high glucose. Methods Cultured human umbilical vein endothelial cells (HUVECs) were divided into six groups: normal glucose control, hyperosmotic control, constant high glucose, fluctuating high glucose, fluctuating high glucose + metformin and fluctuating high glucose + metformin + compound C. After incubation for 72 h, the level of nitric oxide (NO) production was shown as cell supernatant nitrite concentration which was measured by nitrate reductase method; the intracellular level of reactive oxygen species (ROS) was detected by flow cytometry; and the expression levels of adenosine monophosphate activated protein kinase (AMPK), phospho-AMPK (Thr-172, p-AMPK) and guanosine 5'-triphosphate cyclohydrolase-1 (GTPCH1) proteins were determined by western blot. One-way analysis of variance and Q test were applied to analyze the differences among the groups. Results (1) Compared with those in the normal glucose control group (100%), the level of intracellular ROS ( (222±62)% ) was increased and the level of NO ( (70.3±7.1)% ) was reduced in the fluctuating high glucose group. The level of intracellular ROS ( (100±17)% ) was decreased and the level of NO ( (96.3±9.2) % ) was increased in the fluctuating high glucose group by adding metformin. The level of intracellular ROS ( (167.2±19.6)% ) was increased and the level of NO ( (83.3±8.7)% ) was decreased by further adding compound C, an AMPK inhibitor. All the differences were statistically significant (all P<0.05). (2) Compared with those in the normal glucose control group, the expression levels of p-AMPK ( (1.72±0.08) vs (2.34±0.09) ) and GTPCH1 ( (4.07±0.17) vs (7.83±0.56) ) were significantly downregulated in the fluctuating high glucose group. The expression levels of p-AMPK (2.72±0.22) and GTPCH1 (10.24±1.05) were increased in the fluctuating high glucose group by adding metformin. The expression level of GTPCH1 (2.39±0.34) was decreased by further adding compound C. All the differences were statistically significant (all P<0.05). Conclusion Metformin may attenuate intermittent high glucose-induced endothelial dysfunction via upregulating GTPCH1 expression mediated by activation of AMPK signaling pathway. Key words: Metformin; Intermittent high glucose; Endothelial cells; Guanosine 5'-triphosphate cyclohydrolase-1

We investigated whether the adipocytokine, adiponectin, protected the endothelium against damage induced by oxidised low-density lipoprotein cholesterol (oxLDL). Human umbilical vein endothelial cells were cultured with either 200 or 350 microg/ml oxLDL, with or without adiponectin purified from human serum (12 microg/ml). Cellular oxidative status was assessed by measuring reactive oxygen species (ROS), peroxynitrite and glutathione (GSH) levels, while cell function was evaluated by measuring nitric oxide (NO) levels and immunohistochemical examination of proteins in the adherens cell junction. At a concentration of 200 microg/ml, oxLDL induced a small increase in ROS and peroxynitrite levels, a two-fold increase in GSH levels and no changes in NO levels or localisation of proteins in the adherens junction. However, 350 microg/ml of oxLDL induced a marked increase in ROS and peroxynitrite levels, a four-fold reduction in GSH levels and a significant decrease in NO levels and disruption of the adherens junctions. Addition of adiponectin to the cultures resulted in maintenance of normal ROS, peroxynitrite and GSH levels, with no change in either NO levels or protein localisation in the adherens junction. This study demonstrates that adiponectin protects against endothelial dysfunction and cellular disruption induced by oxLDL, with this effect being due, in part, to maintenance of intracellular GSH levels.

Depression is a chronic psychiatric disorder and belongs to one of the leading causes of suicide worldwide. Peroxiredoxins (Prdxs) play a critical role in scavenging excess reactive oxygen species (ROS) and mitigating oxidative stress. However, the role and underlying mechanisms of Prdxs in depression have not been fully illustrated. We carried out lipopolysaccharide (LPS)-induced ICR depression mice and BV2 cell inflammation models. Seven days after LPS-induction, behaviors in ICR mice were assessed by open field test (OFT), sucrose preference test (SPT), and forced swim test (FST), and inflammatory factors levels in serum were quantified via ELISA. The expression levels of Prdxs were evaluated using immunohistochemistry (IHC), western blotting (WB), and RT-qPCR. In LPS-induced BV2 cells, inflammatory factor levels in the supernatant were measured by ELISA. Nitric oxide (NO) levels were detected by biochemical assay. ROS levels were detected via fluorescence signal intensity. Prdxs expression levels were analyzed using WB and RT-qPCR. In LPS-induced ICR mice serum and BV2 cells supernatant, interleukin-1 beta (IL-1β), tumor necrosis factor-alpha (TNF-α), and transforming growth factor-beta1 (TGF-β1) levels exhibited significant elevation (p<0.05). In the hippocampus region of LPS-induced mice and LPS-induced BV2 cells, significant upregulation of Prdx1, Prdx2, Prdx4, and Prdx5 levels was observed (p<0.05). The ROS and NO levels in LPS-induced BV2 cells also significantly increased (p<0.05). This study revealed that Prdx1, Prdx2, Prdx4, and Prdx5 were elevated in depression models, which might relate to the occurrence of neuroinflammation, coupled with upregulation of oxidative stress responses. This study provided new strategies for the treatment of depression.

Patients with minimal hepatic encephalopathy (MHE) show increased oxidative stress in blood. We aimed to assess whether MHE patients show alterations in different types of blood cells in (a) basal reactive oxygen and nitrogen species levels; (b) capacity to metabolise these species. To assess the mechanisms involved in the altered capacity to metabolise these species we also analysed: (c) peroxynitrite formation and d) peroxynitrite reaction with biological molecules. Levels of reactive oxygen and nitrogen species were measured by flow cytometry in blood cell populations from cirrhotic patients with and without MHE and controls, under basal conditions and after adding generators of superoxide (plumbagin) or nitric oxide (NOR-1) to assess the capacity to eliminate them. Under basal conditions, MHE patients show reduced superoxide and peroxynitrite levels and increased nitric oxide (NO) and nitrotyrosine levels. In patients without MHE plumbagin strongly increases cellular superoxide, moderately peroxynitrite and reduces NO levels. In MHE patients, plumbagin increases slightly superoxide and strongly peroxynitrite levels and affects slightly NO levels. NOR-1 increases NO levels much less in patients with than without MHE. These data show that the mechanisms and the capacity to eliminate cellular superoxide, NO and peroxynitrite are enhanced in MHE patients. Superoxide elimination is enhanced through reaction with NO to form peroxynitrite which, in turn, is eliminated by enhanced reaction with biological molecules, which could contribute to cognitive impairment in MHE. The data show that basal free radical levels do not reflect the oxidative stress status in MHE.

Stomata play a crucial role in controlling the rate of photosynthesis and transpiration. Both stomatal opening and closure depend on intricate mechanisms involving several signaling components. The rise in nitric oxide (NO), reactive oxygen species (ROS), and cytosolic pH is necessary for inducing stomatal closure. However, the role of NO and ROS during stomatal opening has not been critically studied. Fusicoccin (FC) and butyric acid (BA) are known to induce guard cell cytosolic acidification and stomatal opening. We conducted a comprehensive study on NO and ROS patterns during stomatal opening induced by FC or BA. Both FC and BA suppressed NO and ROS levels of the guard cells as indicated by specific fluorescent dyes. The external addition of GSNO (natural NO-generator) or H2O2 (source of ROS) significantly suppressed FC- or BA-induced stomatal opening, confirming the requirement of low NO and ROS levels for stomatal opening. In addition, FC and BA lowered the guard cell pH as indicated by the fluorescent indicator, BCECF-AM. The ability of vanadate (PM-ATPase inhibitor) to restrict FC- or BA-induced opening suggested the importance of PM-ATPase-mediated cytosolic acidification, followed by suppression of NO and ROS levels in guard cells during stomatal opening. Further, RT-PCR analysis confirmed the upregulation of PM-ATPase by FC or BA. We propose that the guard cell acidification by FC or BA, due to PM-ATPase, caused the suppression of NO and ROS levels in guard cells and facilitated stomatal opening.

Background and ObjectivePeptic ulcer is a high incidence gastrointestinal disease in China. Berberine (BBR) is a natural product isolated from the Chinese herb Coptis chinensis Franch that has protective effects in digestive diseases. We aimed to evaluate the ability of BBR to attenuate acute gastric ulcer induced by one-time administration of ethanol in the rat.MethodsTissue pathological morphology, macroscopic score, ulcer healing rate, and serum levels of the inflammatory cytokines nitric oxide (NO), interleukin-6 (IL-6), and prostaglandin E2 (PGE2), and anti-inflammatory interleukin-10 (IL-10) were used to determine the efficacy of BBR and evaluated to identify the optimal dosage. Subsequently, transcriptome and metabolome sequencing were conducted in Control, Model, and optimal dosage groups to explore the pathogenesis of the disease and the mechanism of action of the drug. The levels of malondialdehyde (MDA), myeloperoxidase (MPO), as well as those of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) were determined by enzyme-linked immunosorbent assay to verify the results of transcriptomics and metabolomics analyses.ResultsBBR significantly improved the pathological morphology of gastric ulcers, increased the macroscopic score and healing rate, decreased serum levels of NO, IL-6, and PGE2, and increased serum levels of IL-10, thus effectively alleviating gastric ulcer severity. Transcriptome results showed that the therapeutic effect of BBR was mainly mediated by the arachidonic acid metabolism pathway at the gene level, which is closely associated with inflammation and increased levels of reactive oxygen species (ROS). The differentially accumulated metabolite prostaglandin E1, which is a negative regulator of ROS, was significantly up-regulated after BBR administration. The validation results indicated that BBR pretreatment increased SOD and GSH-Px enzyme activities, while reducing levels of the oxidative products MDA and MPO.ConclusionThis study demonstrated that BBR exerts a protective effect on acute gastric ulcer by promoting tricarboxylic acid cycle-mediated arachidonic acid metabolism.

Canine Visceral leishmaniasis (CanL) poses a severe public health threat in several countries. Disease progression depends on the degree of immune response suppression. MicroRNAs (miRs) modulate mRNA translation into proteins and regulate various cellular functions and pathways associated with immune responses. MiR-21 and miR-148a can alter the parasite load and M1 macrophages are the principal cells in dogs’ leishmanicidal activity. A previous study found increased miR-21 and miR-148a in splenic leukocytes (SL) of dogs with CanL using microarray analysis and in silico analysis identified PTEN pathway targets. PTEN is involved in the immune regulation of macrophages. We measured PTEN and the production of reactive oxygen species (ROS) and nitric oxide (NO) before and after transfection SLs of dogs with CanL with mimic and inhibition of miR-21 and miR-148a. PTEN levels increased, NO and ROS decreased in SLs from dogs with CanL. Inhibition of miRNA-21 resulted in PTEN increase; in contrast, PTEN decreased after miR-148a inhibition. Nitrite (NO2) levels increased after transfection with miR-21 inhibitor but were decreased with miR-148a inhibitor. The increase in miR-21 promoted a reduction in ROS and NO levels, but miR-148a inhibition increased NO and reduced ROS. These findings suggest that miR-21 and miR-148a can participate in immune response in CanL, affecting PTEN, NO, and ROS levels.

Objective To investigate whether metformin and liraglutide had a synergistically protective effects on palmitic acid-induced endothelial cell oxidative damage. Methods Human umbilical endothelial cell, which were exposed to palmitic acid for inducing endothelial cell dysfunction, were treated with metformin and/or liraglutide for 24 h. Intracellular level of reactive oxygen species (ROS) was detected by flow cytometry. Supernatant nitric oxide (NO) concentration was measured by nitrate reductase method. One-way ANOVA and Q test were applied to analyze the differences among the groups. Results Compared with control group, 0.25 and 0.50 mmol/L palmitic acid significantly increased intracellular ROS levels ((125±17)%, (189±8)% vs 100%, P<0.05), and decreased supernatant NO levels ((89.9±6.2)%, (79.8±4.8)% vs 100.0%, P<0.05). Either metformin (0.5-1.0 mmol/L) or liraglutide (10-100 nmol/L) treatment alone could significantly prevent the augmented ROS levels and reduced NO levels induced by 0.5 mmol/L palmitic acid. Mono-treatment with low dose of metformin (0.1 mmol/L) or liraglutide (3 nmol/L) did not alter the effects of 0.5 mmol/L palmitic acid on ROS and NO production. However, combination treatment with these doses of the agents significantly prevented the increased ROS levels and decreased NO levels induced by 0.5 mmol/L palmitic acid, shown as decrease of ROS level ((158±31)% vs (250±27)%, P<0.05) and increase of NO level ((91.7±30.6)% vs (82.3±5.0)%, P<0.05). Conclusion Metformin and liraglutide have a synergistic effects in protecting endothelial cell from palmitic acid-induced oxidative damage. Key words: Metformin; Liraglutide; Endothelial cells; Oxidative stress

The significance of nitric oxide (NO) in man was first investigated in the late 1980s, and NO has subsequently received great attention from biologists. Initially, this highly reactive gaseous molecule was seen as a mere noxious air pollutant. Closer investigation of its function in physiological processes, however, revealed that it took part in many different biologic processes. This multifunctionality led to its declaration as the molecule of the year in 1992. We now know NO to be a smooth-muscle relaxant in blood vessels, an inhibitor of platelet aggregation, a neurotransmitter, and a mediator in local defense (2, 3). In the airways, NO is an important molecule with different functions such as stimulation of ciliary motility, mediation in inflammation, bacteriostatic and virostatic activity, and regulation of bronchial airway tone and even pulmonary vascular tone (4–7). Further studies on other systems will probably reveal more processes in which NO plays a key role. Studies in healthy adults indicate that NO in nasal air is mainly produced in the epithelial cells of the nasal cavity, particularly in the paranasal sinuses (8). Many factors, such as smoking, drugs, physio-logical factors, and nasal and paranasal disorder, influence the level of NO measured in nasal air (6, 9, 10). The measurement technique is also of great importance (10, 11). NO measurement has begun to be used in experimental clinical settings, in order to clarify the clinical value of NO in diagnostic problems and therapeutic strategies for disorders such as primary ciliary dyskinesia (PCD) and various forms of sinusitis and allergy. The use of NO as a noninvasive diagnostic and therapeutic tool is the ultimate goal. Many cells within the (upper and lower) respiratory tract can produce NO, including endothelial cells, epithelial cells, neutrophils, and (alveolar) macrophages (12). First, l-arginine is taken up by the cells via cationic transporters (CAT) (Fig. 1). CAT1 is constitutively expressed (housekeeping), while CAT2 is induced by cytokines. Second, l-arginine is N-hydroxylated into NG-hydroxy-l-arginine (NOHA). Subsequently, a three-electron oxidation takes place, resulting in NO and l-citrulline. While NO diffuses to the lumen, l-citrulline can be reconverted to l-arginine via arginosuccinate inside the cell (13). NO metabolic pathway (13) (reproduced with permission). This pathway of generation of NO is regulated by a family of enzymes called nitric oxide synthases (NOS). Three isoforms of NOS have now been identified in man and are differentially distributed in organs and tissues (14). Constitutively expressed nitric oxide synthase (cNOS) consists of two isoforms, nNOS (NOS type 1) and eNOS (NOS type 3), respectively expressed in neurons and vascular endothelium. The activity of nNOS and eNOS is regulated by intracellular calcium/calmodulin concentrations. These isoforms have been localized in human alveolar type II cells and in transformed and primary cultures of human bronchial epithelial cells (15). Inducible NOS (iNOS or NOS type 2) is probably present in every (epithelial) cell, and is activated by proinflammatory cytokines and/or bacterial products (2). The inducible form of NOS is calcium independent. LPS alone increases the production of NO in human epithelial cells, but IFN-γ acts synergistically to enhance this response (15). Immunohistochemical and mRNA in situ hybridization show that NO synthase is expressed apically in the paranasal sinus epithelium, in contrast to the epithelium of the nasal cavity, where only weak NO synthase activity was found (16). The NOS of the paranasal sinuses most closely resembles the inducible isoform but has different characteristics from iNOS expressed elsewhere. These isoforms seem to be constantly expressed and active, and to be resistant to steroids. These properties are associated with constitutive, rather than with inducible, isoforms of NOS (16). A new nonenzymatic pathway has been discovered in man that produces NO by reduction of inorganic nitrite under specific conditions (17). These nonenzymatic reactions take place in the stomach, on the surface of the skin, in the ischemic heart, and in infected nitrite-containing urine. NO generated by this mechanism is likely to play a role in similar biologic events, as when produced from l-arginine by NO synthases. The exact origin of NO measured in nasal air and the relative contribution from other sources are not fully known. Not only is there the production within the nasal cavity and the paranasal sinuses, but there is also a contribution from other sources such as the ambient air and, more important, the lower respiratory tract (6–8, 10, 18, 19). Most studies indicate that the main production of nasal NO is in the paranasal sinuses (16, 20, 21). The first indication is the observation that there is a transient decrease in nasal NO measured from one nostril when air is continuously removed from one maxillary sinus, while air injected into the same sinus results in a transient elevation of nasal NO. This suggests a continuous flow of NO from the maxillary sinus to the nasal cavity (20). Another indication is the reduction of NO release from the paranasal sinuses by instillation of NO synthase inhibitor (L-NAME) into the maxillary sinus. Administration of L-NAME in the nasal cavity results in only a slight reduction of nasal NO levels (20). In patients who have impaired ostial patency, significantly lower nasal NO levels are measured. Impairment of ostial patency and thus lower nasal NO levels are seen in disorders such as Kartagener's syndrome and cystic fibrosis. In these cases, there is probably a lower contribution of NO flowing from the paranasal sinuses into the nose, in addition to a possibly decreased production of NO (8, 22). Moreover, nasal NO levels are high in man and other primates with paranasal sinuses, while, in contrast, the baboon, a primate which lacks paranasal sinuses, has very low nasal NO levels (21). The strong constitutive expression of iNOS in the sinus epithelium and the lack of expression in the nasal epithelium are another indication (16). There are indications that nasal NO levels in children rise until the age of 10 years, when they reach the normal value as in adults. This may be a sign of increasing pneumatization of the developing paranasal sinuses in growing children (16, 23). The role of bacteria in the production of nasal NO has also been suggested; however, most studies showed nasal NO release to be independent of the presence of bacteria, since systemic antibiotics had no effect on the nasal NO values of healthy adults, and the sterile nasal cavities of neonates delivered by cesarean section had measurable nasal NO levels (7, 24, 25). As, in recent years, a wide variety of physiological processes in which NO is involved have been thoroughly investigated, it became clear that NO is important within the system where it is produced. Although initially considered a noxious air pollutant, many scientists now agree on the important roles of NO in different organ systems, such as those of a neurotransmitter in the nervous system, a smooth-muscle relaxant, and an inhibitor of platelet aggregation in the cardiovascular system (6, 16, 26). In the airways, NO seems to be of great importance in local host defense and is a major mediator in many physiological and pathophysiological events, although the exact role of this pluripotent gas is far from fully known. It participates in host defense and inflammation, and as an airborne messenger in bronchial tonus and pulmonary vascular resistance. The role of NO in inflammation is contradictory. Some studies indicate a harmful role of NO in inflammation, whereas others indicate a positive influence (18). There is evidence that NO production is enhanced at sites of inflammation, leading to local increased NO levels, as in asthma, cystitis, and inflammatory bowel disease (18, 27). The harmfulness of NO may be due to extensive production of NO by iNOS in some inflammatory circumstances such as pertussis and asthma, leading to autotoxicity in the affected area (18). However, basal NO production in the upper respiratory tract by a continuous expressed iNOS, leading to fairly high NO levels, has no destructive effect on local airway epithelium, and is even physiological (16). On the contrary, NO production in the upper respiratory tract seems to serve as an important protection against local attack, not as a mere inflammatory mediator, but as a regulator of various protective activities in host defense. A remarkable illustration of the positive role of NO in inflammation was given by McCafferty et al., who found worse inflammation in iNOS knockout mice than in wild-type mice in an animal model of colon inflammation (28). The enhanced production of NO during local aggression against the airway epithelium suggests a role of NO in host defense. NO concentration in normal paranasal sinuses and even in the nasal cavity exceeds greatly NO concentrations that are bacteriostatic (i.e., 100 ppb) (6, 16, 29). Children who have low NO production, as in primary ciliary dyskinesia (PCD) and cystic fibrosis, also have recurrent airway infections, a fact which may be an indication of the (host) protective effect of NO. NO may also have virostatic activities, as indicated in a mouse model (30). There are also indications that NO is active against fungi and parasites, and it may also protect against tumor cells (31). NO is also a regulator of ciliary beat frequency in the upper airway epithelium (4, 5, 32). The lack of NO in nasal air in diseases caused by profound ciliary dysfunction, such as PCD, strongly suggests a relation between NO and ciliary motility with clinical implications. For example, in infection, increased NO production can lead to enhanced ciliary activity, resulting in an effective clearance of aggressive organisms and potentially noxious metabolic products. This can have beneficial results in host defense. Other findings suggest that NO enhances blood flow in the human nasal mucosa (33). Although its possible protective effect is not clear yet, further studies on this subject may elucidate the meaning of this finding. NO produced in the upper respiratory tract follows the airstream to the lower airways and lungs with inhalation. This supports the hypothesis that NO derived from the upper airways has physiological effects in the lung and acts as an aerocrine messenger. There is some evidence that inhaled (exogenous) NO, at concentrations as low as 100 ppb, significantly decreases pulmonary vascular resistance and improves arterial oxygenation in subjects with severe pulmonary disease (33). Other studies suggest that NO helps to decrease the bronchial tonus, although this might be a central rather than a peripheral airway effect (7). NO in gas phase at low concentrations, as in the human airways, is fairly stable and therefore can be detected and quantified. The most widely used technique for measurement of NO in exhaled air is the chemiluminescence method. This highly sensitive technique is based on the emission of electromagnetic radiation from excited NO2*. NO reacts with an excess of ozone (O3), resulting in NO2 with an electron in an excited state (NO2*), which returns to its basic energy by emitting a photon. The quantity of light emitted is proportional to the NO concentration and can be displayed online on-screen. The lower limit of measurement is 1 ppb. Nasal NO measurement is based on the same method as exhaled NO, but sampling can be done directly or indirectly from the nose (6, 10). Other methods that have been used to measure NO in human exhaled air are mass spectrometry and gas chromatography–mass spectrometry (6). The measurement technique that is used in a particular experiment is very important for the eventual value of the nasal NO level (10, 34). Even in the same population the NO level is dependent on the measurement technique (11). The most important factors are ambient NO; the method of measuring (i.e., sampling while breathholding or tidal breathing, soft palate closure, etc.); and the characteristics of the chemiluminescence analyzer, the sampling flow, and the intranasal flow (10, 11). For comparison of different values, it is important to have a notion of these factors. In 1997, the European Respiratory Society Task Force tried to determine a standard method in order to obtain more comparable and reliable values (10). However, scientists continue to use different experimental settings, and one should be aware of this in order to interpret and compare NO values from different studies. The values of oral and nasal NO in the exhaled air of controls measured by the chemiluminescence method vary among laboratories: oral NO ranges from 4 to 160 ppb, while nasal NO varies from 200 to 2000 ppb (12, 22, 23, 35–38). Another remarkable feature is that NO levels are always higher in the upper respiratory tract than in the lower airways in normal subjects (6, 8, 10, 12, 22, 24, 36, 38). The variety of NO values in different studies is due to different factors such as measurement techniques, physiological variations, and pathologic changes (9–11, 16, 23, 34, 39–41). A summary of the influences on nasal NO is given in Table 1. Nasal NO levels rise from birth until the age of 10 years, when they reach the normal adult level. This finding supports the paranasal origin of nasal NO, as in children development of paranasal sinuses results in higher nasal NO levels until the age of 10 years, when they reach their final constitution (16, 23, 43). Interestingly, Schedin et al. found nasal NO already present at birth, including those neonates delivered by cesarean section (25). When nasal NO levels were correlated with body surface, the concentration in children around 10 years of age was approximately twice as high as the nasal NO concentration in adults. The following two possible explanations have been proposed: 1)the surface of paranasal sinuses in children develops faster than the body surface 2)children excrete a larger proportion of NO in the nasal mucosa (16). Another study found that nasal NO levels in adults between 20 and 90 years of age were similar (23). Artlich et al. related levels of nasal NO to the body surface in preterm children and found that the NO excretion is similar to that of adults (about 3 nl/kg/min−1). They concluded that the lower NO levels in preterm children are due to the smaller volume of ventilated sinuses and smaller epithelial surface at that age (43). Mammals without sinuses have no age-related increase in nasal NO (44). Recently, Qian et al. contradicted Lundberg et al.'s conclusions. They showed that intranasal flow had a great influence on the result of NO measurement (16, 34). As there are many differences in ventilation and measurement techniques between children and adults, intranasal flow will not always be comparable. More work needs to be done to make measurements in children and adults more comparable, in order to draw conclusions about age-dependent NO differences (34). There is no evidence that nasal NO levels are sex-related (10, 34, 39). Variation in nasal NO levels in relation to the menstrual cycle has not yet been studied. Several studies show that nasal NO decreases during physical exercise (6, 10, 45). Lundberg et al. (6) showed that nasal NO decreased by 47% after 1 min of physical exercise. A maximal reduction of 76% was found at the end of the exercise period; thereafter, NO levels slowly increased. They reached normal basal levels in about 15–20 min. There are several possible reasons for this decrease in nasal NO. Firstly, changes in nasal cavity volume could result in lower NO levels by dilution of nasal air (46). This possibility has been rejected by a recent finding that nasal NO is independent of nasal cavity volume (47). Secondly, NO could be destroyed by reactive agents produced in the nasal mucosa during physical exercise. Thirdly, changes in NO could be caused by a reduction of blood flow in the nasal mucosa with a concomitant decrease in substrate supply to the highly producing NOS type 2 in the paranasal sinuses (6, 46). Smoking control subjects have somewhat lower exhaled NO and nasal NO values than age- and sex-matched nonsmokers. The reason for this could be related to the toxic effect of inhaled smoke on the downregulation in NOS and/or the disruption of NO-producing cells (6, 10, 23). When evaluating the effect of drugs on nasal NO, one should be aware of interactions among drugs, patients, and diseases. It is not always easy to determine whether the changes in nasal NO are caused by the drug or by the disease itself. Topical and systemic glucocorticoids showed no effect on the nasal NO levels in healthy people (6, 8, 48, 49). Antibiotics in healthy persons do not alter nasal NO levels (6, 8). Topical nasal decongestants, such as oxymetazoline, result in a decrease of nasal NO levels (6, 10, 40, 47, 50). The reason for this may be a reduction, caused by vasoconstriction, in substrate supply to the high-output NOS type 2 in the sinuses. Histamine seems to have no influence on nasal NO levels (51). Nasal NO levels in people suffering from an upper respiratory tract infection (URTI) do not differ from nasal NO levels in healthy people. Specifically, Ferguson & Eccles (50) and Lindberg et al. (23) found no significant differences in nasal NO levels during and after an episode of URTI. Lindberg et al. (23) found similar nasal NO levels in patients with URTI and healthy controls (23). Baraldi et al. reached the same conclusion when comparing children with and without URTI (41). The effect of allergic rhinitis on nasal NO is not consistent. Some researchers report higher nasal NO levels in patients with allergic rhinitis (9, 40, 42). This may be due to an upregulation of iNOS by local infection, resulting in higher NO production (9). Kharitonov et al. found that nasal NO levels in patients suffering from allergic rhinitis and treated with topical nasal glucocorticoids are even lower than nasal NO levels in controls (9). This led to the hypothesis that iNOS in nasal epithelial cells gives rise to increased nasal NO levels in allergic rhinitis and contributes to the normal NO production in basal circumstances, since topical nasal glucocorticoids normally do not reach the sinus cavity and decrease nasal NO values in allergic rhinitis to levels lower than nasal NO levels in controls. According to this hypothesis, iNOS in the nasal cavity, as its activity is altered by glucocorticoids, must be different from iNOS found in the paranasal sinuses, which is not influenced by glucocorticoids (9, 52). Lundberg et al. (36) and Henriksen et al. (53) found no alterations in nasal NO levels in patients with allergic rhinitis. The cause of these discrepancies is not very clear. One could speculate that the upregulation of iNOS in the nose leads to higher nasal NO levels in rhinitis, as is the case in local infections in the lower airways, such as asthma (9, 52, 54). In contrast, swelling of the nasal mucosa in rhinitis can lead to occluded sinus ostia, which results in a reduced passage of NO from the paranasal sinuses to the nasal cavity, where it is measured (40). An interesting finding supporting this view was made by Arnal et al. (40), who found increased nasal NO levels in patients with allergic rhinitis. But patients without symptoms at the moment of the measurement had even higher nasal NO levels than patients with symptoms. One could postulate that nasal NO levels in patients with symptoms are lower because of a reduced contribution of the NO produced in the paranasal sinuses, as a result of obstructed sinus ostia. In patients without symptoms, ostial patency is mostly better leading to a higher of NO from the paranasal sinuses into the nasal cavity (40). in the nasal NO level measure may be the result of in the may even This must be taken into when a given nasal NO value is Nasal NO levels seem not to be influenced by asthma (18, 22, 36, One can that asthma the upper respiratory tract to a than the lower airways, where increased NO levels are of glucocorticoids can NO levels by reduction of iNOS NO levels are considered to be a of airway measurement of NO levels in the lower airways could indicate the of (6, 22). Nasal NO levels seem to be decreased in patients suffering from but not studies are consistent. Lindberg et al. patients with sinusitis and found that nasal NO production was reduced by more than in comparison with healthy subjects (23). In contrast, Arnal et al. found no significant differences in their study of patients with sinusitis Lindberg et al. found similar nasal NO levels in patients after sinusitis and healthy subjects (23). nasal NO levels were measured by Baraldi et al. in children with These decreased nasal NO levels increased after with systemic nasal NO levels were to the levels of healthy children (41). It has not yet been whether low nasal NO levels in sinusitis result from reduced passage of NO via the sinus ostia, or whether the NO production is reduced in those patients (41). A low production of NO as a cause of low nasal NO levels in sinusitis is by the study of Lindberg et al., who found nasal NO levels to be low sinus or by sinus as by (23). In contrast to Lindberg et al.'s Baraldi et al. found only a reduced NO level in children with a of the sinus in the air derived from the nostril (41). The effect of nasal has not been The of nasal NO and nasal has been in only one Arnal et al. increased nasal NO levels in patients with nasal and to whereas patients with nasal without had significantly lower nasal NO The nasal NO concentration in patients with allergic was significantly higher than in patients with For a similar of sinus nasal NO was higher in allergic than in This that is an important in relation to the level of nasal NO in In the nasal NO concentration was correlated with the of alterations of the paranasal sinuses. This that the of the paranasal sinuses by the decreases the nasal NO with a similar of of the nasal NO levels was that sites of production other than the sinuses also to the nasal NO. It has been that also may to the NO production, as they also iNOS in their epithelial cells (2). can that the of paranasal sinus and the allergic strongly influence the nasal NO level in nasal studies report very low nasal NO levels in patients suffering from cystic (12, 22, This may be the result of reduced NO production by destroyed epithelial cells or reduced NOS An increased NO into the sinus and a reduced NO passage from the sinuses to the nasal cavity may be another possible (12, 22, Kartagener's syndrome is a and They are part of In patients with PCD, nasal NO levels are (8, 12, 52). explanations are reduced NO production by a reduced from the nasal and paranasal and reduced passage of NO via the sinus (8, 12, 22, 52). In studies on PCD, significantly lower nasal NO levels in than in disease controls. nasal NO values, however, do not We found that the in have no significant influence on the nasal NO level et al., of NO can an interesting and diagnostic and therapeutic However, to be done in order to make it a in This noninvasive measurement can be even in It could be used as an easy for the of In the therapeutic may It is to that drugs will be used to or decrease NO production in such a that it can have a positive influence on However, there is to be in the various physiological and pathologic factors, such as that nasal NO, particularly the should on and on measurements more reliable and comparable. NO is a gaseous the significance of which in man to be investigated in the late the it has the attention of many who have revealed its significance in various physiological and pathologic processes. It has functions in the cardiovascular system, the nervous system, and the upper and lower In the airways, NO levels in the upper respiratory tract are higher ppb) than those in the lower respiratory tract The chemiluminescence which is based on a of NO with resulting in the emission of is the most widely used measurement technique for NO. NO has a major influence on airway by mediation in ciliary activity, inflammation, host bronchial and pulmonary vascular resistance. It is also considered to be an aerocrine messenger between the upper and lower such as physical smoking, and some drugs influence physiological nasal NO concentrations. conditions such as allergic rhinitis, nasal cystic fibrosis, and lead to altered nasal NO concentrations. of nasal NO can be at and can be used to for disease or to the effects of However, the clinical of the measurement of nasal NO in different physiological and pathologic conditions to be it can be used as a diagnostic on the function of NO in and is its in diagnostic and therapeutic of some

A benzoxazine derivative induces vascular endothelial cell apoptosis in the presence of fibroblast growth factor-2 by elevating NADPH oxidase activity and reactive oxygen species levels

Background and objective: Blisters on the human skin and mucous membranes are a hallmark of the extremely rare autoimmune disease known as Pemphigus vulgaris (PV). Elevated levels of reactive oxygen species (ROS) are linked to this condition. Nitric oxide (NO), produced by endothelial cells, is a key signaling molecule that contributes to vascular function and can act as an antioxidant by neutralizing reactive oxygen species in specific biological contexts. A substance that resembles a vitamin, L-carnitine, positively influences antioxidant levels. This study aimed to investigate the impact of L-carnitine supplementation on serum nitric oxide levels in patients with Pemphigus vulgaris. Method and materials: This clinical trial included a total of 46 patients with Pemphigus Vulgaris, aged between 30 and 65 years. Participants were randomly divided into two groups: one receiving L-carnitine (n = 23) and the other a placebo (n = 23). Each group took either 2000 mg of L-carnitine or placebo tablets daily. The intervention was conducted over 8 weeks, with serum L-carnitine and nitric oxide (NO) levels assessed both before and after the intervention. Results: At baseline, the intervention and control groups did not differ statistically significantly in terms of age, weight, height, and BMI (p &gt; 0.05). By the end of the study, patients in the L-Carnitine group showed a significant increase in serum L-Carnitine levels (from 74.56±36.36 to 97.49±41.27, p&lt;0.001) and in nitric oxide (NO) concentration (from 202.37±14.59 to 242.98±20.63, p=0.006) In contrast, the placebo group did not show any significant changes in either parameter (p&gt;0.05). Conclusion: A daily intake of 2 g of L-carnitine for 8 weeks in patients with PV has positive effects on reducing oxidative stress and increasing serum nitric oxide levels.