High Levels Of Nitric Oxide Research Articles

Selenium deficiency influences the gene expressions of heat shock proteins and nitric oxide levels in neutrophils of broilers.

The aim of the present study was to investigate the effects of selenium (Se) deficiency on the expressions of heat shock proteins (Hsp90, 70, 60, 40, and 27) and nitric oxide (NO) levels in neutrophils of broilers. One hundred eighty 1-day-old broilers were randomly assigned into two groups and were fed on a low-Se diet (0.008mg/kg Se) or a control diet (0.2mg/kg Se), respectively. Then, the messenger RNA (mRNA) levels of Hsp90, 70, 60, 40, and 27, induced nitric oxide synthase (iNOS), and NO levels were examined. The results showed that Se deficiency increased the mRNA levels of Hsps and iNOS and induced higher level of NO in chicken neutrophils (P < 0.05). It showed that the expression of Hsp40 increased higher than other Hsps in neutrophils, which indicated that it might play the crucial protective role in neutrophils. In addition, correlation analysis showed that iNOS had the biggest correlation with Hsp60, which indicated that Hsp60 might play an important function in inhibiting the production of NO, and the correlation coefficient between Hsp60 and Hsp70 was over 0.9, which indicated that they might have a synergistic effect. These results suggested that the level of NO and Hsp expression levels in neutrophils can be influenced by Se deficiency. And Hsp40 might play the crucial protective role in neutrophils induced by Se deficiency.

Nitric oxide in human gingival crevicular fluid after orthodontic force application

Nitric oxide (NO) is involved in bone remodelling and has been shown to play a role in regulating the rate of orthodontic tooth movement (OTM) in rat models. In humans, however, the role of NO in OTM remains less clear. In this study, NO concentration in gingival crevicular fluid (GCF) was measured in patients undergoing orthodontic treatment. Thirteen male participants (ages 11–18 years) planned for non-extraction fixed orthodontic therapy were recruited. Samples of GCF were collected from each maxillary central incisor and first and second molar immediately before (T0), 1h after (T1), and 3–4 days after (T2) application of light orthodontic forces. The maxillary second molars were not included in the appliance and served as controls. Measureable NO levels were consistently obtained from all sampled sites. Total NO levels showed significantly higher NO levels (p<0.05) at T1 at the buccal surfaces of the central incisors when compared to the first and second molars. The results indicate a possible role for NO in OTM at the pressure sites of incisors at early time points. Further studies are required to determine whether NO levels in the periodontal ligament tissues of human teeth during OTM are affected by a force gradient and the magnitude of the applied force.

The mechanisms governing low denitrification capacity and high nitrogen oxide gas emissions in subtropical forest soils in China

Previous studies have demonstrated that denitrification rates are low in subtropical forest soils. However, the mechanisms governing this process are not well known. This study seeks to identify the mechanisms responsible for the low denitrification capacity and high nitrogen oxide gas ratio in subtropical forest soils in China. The denitrification capacity and nitric oxide (NO), nitrous oxide (N2O), and dinitrogen (N2) emission rates were measured using the acetylene inhibition method under conditions of added nitrate and anoxia. The abundance of nitrate reductase (narG), nitrite reductase (nirK), nitric oxide reductase (cnorB), and nitrous oxide reductase (nosZ) was measured using real-time, quantitative polymerase chain reaction, and sequencing of the nirK and norB products was performed to analyze the population structure of denitrifying bacteria. These results showed that the denitrification capacity in subtropical forest soils was lower than in temperate forest soils (p < 0.05). Multiple regression analysis showed that redox potential at the start of incubation (Ehi), rather than soil pH or soil organic C, was the key soil variable influencing denitrification, and Ehi alone could explain 68% of the variations in denitrification capacity. The high Ehi in subtropical soils led to a low abundance of nirK and significant differences in the population structure of denitrifying bacteria between subtropical and temperate soils. Therefore, Ehi was responsible for the low denitrification capacity in subtropical forest soils. The ratio of NO to total denitrification gas products (p < 0.01) and the ratio of NO and N2O to total denitrification gas products (p < 0.05) were significantly higher in subtropical forest soils than in temperate forest soils, while the reverse trend was observed for the ratio of N2 to total denitrification gas products (p < 0.05). A high Ehi reduced the specific reduction activity of each nosZ copy and, in turn, resulted in a large ratio of NO and N2O to total denitrification gas products in subtropical soils. Thus, NO and N2O, but not N2, were the dominant denitrification gas products, accounting for 80%, even under the highly anaerobic conditions in subtropical forest soils and despite low denitrification capacity. These results were significant for understanding the “Hole in the Pipe” model and NO and N2O gases emission in subtropical forest soils. Despite the fact that the nitrogen flowing through the pipe (denitrification capacity) was low, the large holes in the pipe resulted in a large quantity of NO and N2O gases leaking out. This leakage may be a potential mechanism for the high levels of NO and N2O gas emission in subtropical forest soils and could partly explain why NO and N2O emissions are generally high in subtropical and tropical soils.

AB0506 Study of Serum Nitric Oxide Level in Patients with Lupus Nephritis and Its Relation to Disease Activity

BackgroundSLE is characterized by the production of a wide range of autoantibodies and immune complexes that may lead to tissue injury. Among patients with Lupus Nephritis; those with proliferative lesions...

Dexamethasone and recombinant human activated protein C improve myocardial function and efficiency during experimental septic shock.

Corticosteroids have been shown to reduce short-term mortality during septic shock and therefore recommended in the most severe patients as adjuvant therapy. Until recently, recombinant human activated protein C (APC) was also considered in the management of more severe cases. As myocardial depression has long been recognized as a manifestation of organ dysfunction during septic shock, we examined whether corticosteroids (dexamethasone, 150 µg/kg per hour) and/or APC (33 µg/kg per hour) treatments improve sepsis-induced cardiac dysfunction during cecal ligature and puncture-induced septic shock in Wistar rats. All rats received intravenous saline resuscitation (10 mL/kg per hour) and antibiotics. Eighteen hours after surgery, anesthesia was performed (isoflurane), and myocardial function was assessed using a conductance catheter introduced into the left ventricle. Rats were then killed; blood and heart were harvested for biological analysis, including radical oxygen species determination. Cecal ligature and puncture induced hypotension, depression of myocardial systolic performance (demonstrated by significant decreases in dP/dtmax [first derivative of maximal developed pressure during isovolumetric contraction], end-systolic pressure-volume relationship, and preload recruitable stroke work) and alteration of diastolic function (dP/dtmin [first derivative of minimal developed pressure during isovolumetric relaxation]), whereas dexamethasone, APC, and their combination thereof allowed correction of hemodynamic disorders and improved myocardial mechanical efficiency. Cecal ligature and puncture was associated with higher levels of nitric oxide and superoxide anion (O2) in heart (electron paramagnetic resonance studies) and consequently peroxynitrite. Dexamethasone and APC also improved cardiac dysfunction by downregulating the inducible nitric oxide synthase pathway and reducing myocardial oxidative stress.

The design of nitric oxide donor drugs: s-nitrosothiol tDodSNO is a superior photoactivated donor in comparison to GSNO and SNAP

We have recently developed tert-dodecane S-nitrosothiol (tDodSNO) as a photoactivated nitric oxide (NO) donor. We here compare the potency of tDodSNO to S-nitrosoglutathione (GSNO) and S-nitroso-N-acetylpenicillamine (SNAP), drugs which are also based upon the S-nitrosothiol functionality and have been extensively used for NO release studies. Photoactivation in vitro, at a clinically relevant light fluence rate (200W/m2), demonstrated that tDodSNO released much higher levels of NO than either GSNO or SNAP. When evaluated in an ex vivo aortic ring vasorelaxation assay, tDodSNO was also the only drug to exhibit a photodynamic response, with an 8 fold decrease in EC50 (8.1–1.0µM) upon irradiation. While both GSNO and SNAP induced NO dependent vasorelaxation at lower concentrations than tDodSNO (EC50׳s of 158 and 38nM respectively), this activity was due to their rapid metabolic decomposition, and could not be modulated by photoactivation. Additionally, tDodSNO׳s photodynamic response allowed vascular tone to be directly regulated by light intensity. Molecular modeling of drug properties suggested that these differences in activity could be attributed to a combination of an increase in tDodSNO׳s hydrophobicity, and substantial steric shielding of molecule׳s S-nitrosothiol group from solvent interactions. In conclusion, our study demonstrates that tDodSNO is currently the most effective known s-nitrosothiol for phototherapeutic applications.

Activation of neuronal nitric oxide synthase (nNOS) signaling pathway in 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-induced neurotoxicity

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) has been reported to cause alterations in cognitive and motor behavior during both development and adulthood. In this study, the neuronal nitric oxide synthase (nNOS) signaling pathway was investigated in differentiated pheochromocytoma (PC12) cells to better understand the mechanisms of TCDD-induced neurotoxicity. TCDD exposure induced a time- and dose-dependent increase in nNOS expression. High levels of nitric oxide (NO) production by nNOS activation induced mitochondrial cytochrome c (Cyt-c) release and down-regulation of Bcl-2. Additionally, TCDD increased the expression of active caspase-3 and significantly led to apoptosis in PC12 cells. However, these effects above could be effectively inhibited by the addition of 7-nitroindazole (7-NI), a highly selective nNOS inhibitor. Moreover, in the brain cortex of Sprague–Dawley (SD) rats, nNOS was also found to have certain relationship with TCDD-induced neuronal apoptosis. Together, our findings establish a role for nNOS as an enhancer of TCDD-induced apoptosis in PC12 cells.

IFN-γ and TNF-α are involved during Alzheimer disease progression and correlate with nitric oxide production: a study in Algerian patients.

Alzheimer's disease (AD) is a neurodegenerative disease leading to a progressive and irreversible loss of mental functions. It is characterized by 3 stages according to the evolution and the severity of the symptoms. This disease is associated with an immune disorder, which appears with significant rise in the inflammatory cytokines and increased production of free radicals such as nitric oxide (NO). Our study aims to investigate interferon (IFN)-γ and tumor necrosis factor-α (TNF-α) involvement in NO production, in vivo and ex vivo, in peripheral blood mononuclear cells from Algerian patients (n=25), according to the different stages of the disease (mild Alzheimer's, moderate Alzheimer's, and severe Alzheimer's) in comparison to mild cognitive impairment (MCI) patients. Interestingly, we observed that in vivo IFN-γ and TNF-α levels assessed in patients with AD in mild and severe stages, respectively, are higher than those observed in patients with moderate stage and MCI. Our in vivo and ex vivo results show that NO production is related to the increased levels of IFN-γ and TNF-α, in mild and severe stages of AD. Remarkably, significant IFN-γ level is only detected in mild stage of AD. Our study suggests that NO production is IFN-γ dependent both in MCI and mild Alzheimer's patients. Further, high levels of NO are associated with an elevation of TNF-α levels in severe stage of AD. Collectively, our data indicate that the proinflammatory cytokine production seems, in part, to be involved in neurological deleterious effects observed during the development of AD through NO pathway.

Neutrophils are critical in the pathogenesis of atypical EAE in LysMCre-SOCS3fl/fl mice (IRC5P.471)

Abstract Experimental autoimmune encephalomyelitis (EAE) is an autoimmune disease of the central nervous system (CNS) characterized by demyelination, inflammatory lesions and axonal damage. We previously demonstrated that deletion of Suppressor of Cytokine Signaling 3 (SOCS3) in myeloid cells resulted in atypical EAE with a striking neutrophil infiltration in the brain. In this study, we investigated the role of neutrophils in the pathogenesis of atypical EAE. Kinetics studies show that accumulation of neutrophils in LysMCre-SOCS3fl/fl mice correlate with disease development. Ab-mediated depletion of neutrophils delays the onset of atypical EAE and prolongs survival. Importantly, brain-infiltrating neutrophils display high expression of CXCR2, and produce high levels of CXCL2, CCL2 and nitric oxide (NO). In addition, LysMCre-SOCS3fl/fl recipients develop atypical EAE in Th1- and Th17-adoptive transfer models. Our findings indicate that, in LysMCre-SOCS3fl/fl mice, neutrophils facilitate the disruption of the blood-brain barrier (BBB), and once they gain access to the brain, they play an essential role in the development of atypical EAE by promoting their own recruitment through production of CXCL2, and promoting macrophage recruitment through production of CCL2. More importantly, the activated neutrophils produce high levels of NO, resulting in inhibition of regulatory T-cells, oligodendrocyte damage and axonal degeneration, which leads to atypical EAE in LysMCre-SOCS3fl/fl mice.

Ginsenoside Rg3 Enhances Islet Cell Function and Attenuates Apoptosis in Mouse Islets

BackgroundThe transplantation of isolated islets is thought to be an attractive approach for curative treatment of diabetes mellitus. Panax ginseng has been used in oriental countries for its pharmacologic effects, such as antidiabetic and antiinflammatory activities. 20(S)-ginsenoside Rg3 (Rg3), an active ingredient of ginseng saponins, has been reported to enhance insulin secretion–stimulating and antiapoptotic activities in pancreatic beta cells. We performed this study to examine the hypothesis that preoperative Rg3 administration can enhance islet cell function and antiapoptosis before islet transplantation. MethodsBalb/c mice were randomly divided into 2 groups according to the administration of Rg3 after islet isolation. Mouse islets were cultured in medium supplemented with or without Rg3. In vitro, islet viability and function were assessed. After treatment of islets with a cytokine cocktail (tumor necrosis factor α, interferon-γ, and interleukin-1β), cell viability, function, and apoptosis were assessed. ResultsCell viability was similar between the 2 groups. Islets cultured in medium supplemented with Rg3 showed 2.3-fold higher glucose-induced insulin secretion than islets cultured in medium without Rg3. After treatment with a cytokine cocktail, glucose-induced insulin release, total insulin content of islets, and apoptosis were significantly improved in Rg3-treated islets compared with cytokine-treated islets. Cytokine-treated islets produced significantly higher levels of nitric oxide (NO) than islets treated with Rg3. ConclusionsThese results suggest that preoperative Rg3 administration enhanced islet function before islet transplantation and attenuated both cytokine-induced damage associated with NO production and apoptosis. Rg3 administration might be a prospective management to enhanced islet function and ameliorate early inflammation after transplantation.

Experimental evidence for involvement of nitric oxide in low frequency magnetic field induced obsessive compulsive disorder-like behavior

It is well documented that extremely low frequency magnetic field (ELF MF) produced effects on the function of nervous system in humans and laboratory animals. Dopaminergic and serotonergic pathways have been implicated in obsessive compulsive disorder (OCD). Recently involvement of nitric oxide (NO) in OCD-like behavior is suggested. Hence, the present study was carried out to understand the involvement of dopamine, serotonin and NO in ELF MF induced OCD-like behavior. Swiss albino mice were exposed to ELF MF (50Hz, 10G) for 8h/day for 7, 30, 60, 90 and 120days by subjecting them to Helmholtz coils. OCD-like behavior was assessed in terms of marble burying behavior (MBB) test. Results revealed that ELF MF induced time dependant MBB, on 7th, 30th, 60th, 90th, and 120th exposure day.Further, levels of dopamine, serotonin and NO after 120days of ELF MF exposure were determined in the regions of the brain. The neurohumoral studies revealed that exposure to ELF MF increased NO levels in cortex, hippocampus and hypothalamus, and levels of dopamine and serotonin remain unaffected. As OCD-like behavior after ELF MF exposure was associated with higher levels of NO with no significant change in serotonin and dopamine. The effect of such exposure was studied in groups concurrently treated with NO modulators, NO precursor, l-ARG (400mg/kg) or NOS inhibitor, l-NAME (15.0mg/kg) or 7-NI (10.0mg/kg). These treatments revealed that NO precursor exacerbated and NOS inhibitors attenuated ELF MF induced OCD-like behavior with corresponding changes in the levels of NO.

Targeting colon cancer cell NF-κB promotes an anti-tumour M1-like macrophage phenotype and inhibits peritoneal metastasis

In a model of peritoneal metastasis in immune-competent mice, we show that nuclear factor (NF)-κB inhibition in CT26 colon cancer cells prevents metastasis. NF-κB inhibition, by stable overexpression of IκB-α super-repressor, induced differential polarization of co-cultured macrophages to an M1-like anti-tumour phenotype in vitro. NF-κB-deficient cancer cell-conditioned media (CT26/IκB-α SR) induced interleukin (IL)-12 and nitric oxide (NO) synthase(inducible NO synthase (iNOS))expression in macrophages. Control cell (CT26/EV) conditioned media induced high levels of IL-10 and arginase in macrophages. In vivo, this effect translated to reduction in metastasis in mice injected with CT26/ IκB-α SR cellsand was positively associated with increased CD8(+)CD44(+)CD62L(-)and CD4(+)CD44(+)CD62L(-)effector T cells. Furthermore, inhibition of NF-κB activity induced high levels of NO in infiltrating immune cells and decreases in matrix metalloproteinase-9 expression, simultaneous with increases in tissue inhibitor of metalloproteinases1 and2 within tumours. CT26/IκB-α SR tumours displayed increased pro-inflammatory gene expression, low levels of angiogenesis and extensive intratumoral apoptosis, consistent with the presence of an anti-tumour macrophage phenotype. Macrophage depletion reduced tumour size in CT26/EV-injected animals and increased tumour size in CT26/IκB-α SR cells compared withuntreated tumours. Our data demonstrate, for the first time, that an important implication of targeting tumour cell NF-κB is skewing of macrophage polarization to an anti-tumour phenotype. This knowledge offers novel therapeutic opportunities for anticancer treatment.

Ultrastructural study on Biomphalaria alexandrina haemocytes infected with Schistosoma mansoni in Egypt and its correlation with nitric oxide level.

Some snails of Biomphalaria alexandrina can resist the infection of Schistosoma mansoni so this study aimed to clearly this mechanism by using light and electron microscopy (EM) and determine the role of Nitric oxide in this mechanism. B. alexandrina snails used in this study were exposed individually to S. mansoni infection according to their response they were classified into susceptible group (shed cercariae) and resistant group (failed to shed cercariae). Snails not exposed to infection were included in this study as control group. Nitric oxide (NO) level was assayed directly in the soluble fraction of B. alexandrina haemolymph supernatants collected from each group of B. alexandrina snails were subjected to NO assay by the Greiss reaction. The level of NO in haemolymph of infected snails was significantly increased (p < 0.001) than both control and non infected snails groups, however, in non infected snails group had significantly (p < 0.05) compared to control group. This study when correlated the changes recognized by EM with NO level the pro apoptotic effect of high level of NO on the haemocytes. Characterization and identification of cell shape of haemocytes in both haemolymph and tissue were examined by light and electron microscopy. Examination of B. alexandrina snail's haemocytes revealed three types of different cells classified according to their shape and granular contents. These cells are granulocytes, amoebocytes and hyalineocytes. Electron microscope study also revealed the important role of granulocytes and amoebocytes as defense mechanism against snail infection. NO is considered an important anti parasite molecule; intra-molluscan stages of parasites switch off host NO defense response.

Inflammation characteristics in bladder pain syndrome ESSIC type 3C/classic interstitial cystitis

Interstitial cystitis is regarded as a heterogenous syndrome with two distinguishable forms: the non-ulcer and the classic form of interstitial cystitis, the latter with Hunner's lesions; or bladder pain syndrome type 3C and non-Hunner bladder pain syndrome, respectively. A cohort of 379 patients diagnosed with interstitial cystitis was studied. Nitric oxide release from the bladder was measured using a chemiluminescence nitric oxide analyzer. Bladder biopsies from the patients and healthy controls were analyzed by routine histopathological examination. Biopsies from a subset of patients and controls were also analyzed by immunohistochemistry and cytokine gene expression by real-time polymerase chain reaction. Patients with bladder pain syndrome type 3C/classic interstitial cystitis had considerably higher levels of nitric oxide as compared with non-Hunner bladder pain syndrome/non-ulcer interstitial cystitis patients and healthy individuals, and showed histologically a chronic inflammation in the bladder mucosa, with abundant mast cell infiltration in all layers of the bladder wall. No inflammation was noted in non-Hunner bladder pain syndrome/non-ulcer interstitial cystitis patients. The isoenzymes inducible nitric oxide synthase, the catalyst in the nitric oxide production, was strongly expressed in the inflammatory cells in the bladder mucosa of bladder pain syndrome type 3C/classic interstitial cystitis patients. In addition, the expression of the pro-inflammatory cytokines interleukin-6 and interleukin-17A messenger ribonucleic acid, and of anti-inflammatory interleukin-10 messenger ribonucleic acid showed significantly increased levels in bladder pain syndrome type 3C/classic interstitial cystitis compared with healthy controls. Bladder pain syndrome type 3C/classic interstitial cystitis is a distinct inflammatory disease and in many aspects shares features of inflammatory autoimmune diseases. These findings could open up novel research avenues with expectations for new targets for pharmacological treatment.

Nitric Oxide Donors with Therapeutic Strategic in Experimental &lt;i&gt;Schistossomiasis Mansoni&lt;/i&gt;

Schistosomiasis, an immune disease, remains a major public health problem in endemic area. To determine the influence of Nitric Oxide (NO) on this disease, we tested two compounds (Trans-[Ru(bpy)2(NO)SO3](PF6)-PF6 and Na2[Fe(CN)5(NO)]-SNP, which releases NO when activated by biological reducing agents, in BALB/c mice infected subcutaneously by Schistosoma BH strains. The parasitic activity of NO-donors was evaluated in this model by measuring the immune cellular response in liver with: Cytokines levels; histopathological characteristics and the number of the granulomatous lesions; and NO levels. We found that NO-donors treated mice were more resistant to infection, since they exhibited higher survival. Furthermore, we observed in histopathological analysis a decreased influx of inflammatory cells in the hepatic tissue of mice treated with both donors. The parasite counting (estimated as eggs and worms number) was also minor in treated mice. Moreover, decreased levels of IL-10 were detected in the liver of infected mice treated with SNP. The animals treated with PF6 showed high plasmatic NO levels at 45 days after infection. Altogether, these data suggest that NO is a pivotal factor of resistance during schistossomiasis by controlling parasites proliferation, influencing cytokine production and consequently modulating the development of inflammatory response.

Biochemical and immunological studies on erythrocytes superoxide dismutase modified by nitric oxide in patients with alopecia areata: Implications in alopecia patchy persistent and alopecia universalis

Alopecia areata (AA) is a non-scarring hair loss disorder that ranges in severity from patchy loss of scalp hair (AA patchy persistent; AAP) to loss of all scalp and body hair (alopecia universalis; AU). The cause of AA is unknown but most evidences support that AA has an autoimmune etiology, where free radicals play an important role. This study was undertaken to investigate the role of nitric oxide (NO) modified erythrocytes superoxide dismutase (eSOD) in AA. Data revealed that NO-induced damage in eSOD caused alteration in hydrophobic or aromatic amino acids and protein carbonyl contents. NO-specific quencher, carboxyl-PTIO further reiterates NO-modifications. Specificity of antibodies from AA patients (n=26) was analyzed toward NO-modified eSOD (NO-eSOD) and their results were compared with healthy controls (n=30). Protein-A purified IgG of AA patients (AA-IgG) showed strong binding to NO-eSOD in comparison with IgG from controls. In addition, AA-IgG from patients with AU recognized NO-eSOD in a greater extent as compared to AA-IgG from patients with AAP. Furthermore, AU patients’ sera contained higher levels of NO or carbonyl contents and lower levels of SOD activity compared with AAP patients’ or control sera. In conclusion, this is the first study to demonstrate the role of NO-modified-eSOD in AA. Our novel results conclude that perturbations in SOD by NO presenting unique neo-epitopes that might be one of the factors for the antigen driven antibodies induction in AA. Preferential binding of NO-eSOD by AA-IgG pointed out the likely role of NO-eSOD in the initiation/progression of AA.

Inhaled microparticles of antitubercular antibiotic for in vitro and in vivo alveolar macrophage targeting and activation of phagocytosis

Tuberculosis (TB) is a chronic infectious disease with increasing incidence of drug resistance. Oral treatment for TB and multidrug resistance-TB can have serious side effects. The causative agent of TB, Mycobacterium tuberculosis, resides in alveolar macrophages (AMs). Pulmonary administration of antitubercular (anti-TB) antibiotic can help in delivery of high concentration to AM. The ability of AM to phagocytose can also be utilized to generate mycobactericidal nitric oxide (NO) to improve efficacy of anti-TB antibiotics. The objective in this investigation was made to prepare isoniazid microparticles (IM) and polymeric microparticles of isoniazid (INH-PM) using poly-ε-caprolactone as polymer and to evaluate in vitro through cell culture techniques and in vivo through pulmonary administration of IM and INH-PM for uptake of isoniazid by AM. The hepatotoxicity was determined through serum glutamate oxaloacetate transferase (SGOT) and serum glutamate pyruvate transferase (SGPT) levels and histological examination. The results depicted that the significantly higher (P<0.05) concentration of isoniazid was found in AM with INH-PM in vitro and in vivo. NO production was also significantly higher but less than toxic level. SGOT and SGPT levels, uptake of INH by liver and histological examination were indicative of no hepatotoxicity with INH-PM and IM. Phagocytosis of IM and INH-PM leads to significantly higher drug level in AM as well as production of significantly higher levels of NO without compromising the viability of cells. The administration of IM and INH-PM as dry powder inhalation formulation may reduce the treatment time of TB and chances of drug-resistant TB.

Simplified 2-Aminoquinoline-Based Scaffold for Potent and Selective Neuronal Nitric Oxide Synthase Inhibition

Since high levels of nitric oxide (NO) are implicated in neurodegenerative disorders, inhibition of the neuronal isoform of nitric oxide synthase (nNOS) and reduction of NO levels are therapeutically desirable. Nonetheless, many nNOS inhibitors mimic l-arginine and are poorly bioavailable. 2-Aminoquinoline-based scaffolds were designed with the hope that they could (a) mimic aminopyridines as potent, isoform-selective arginine isosteres and (b) possess chemical properties more conducive to oral bioavailability and CNS penetration. A series of these compounds was synthesized and assayed against purified nNOS enzymes, endothelial NOS (eNOS), and inducible NOS (iNOS). Several compounds built on a 7-substituted 2-aminoquinoline core are potent and isoform-selective; X-ray crystallography indicates that aminoquinolines exert inhibitory effects by mimicking substrate interactions with the conserved active site glutamate residue. The most potent and selective compounds, 7 and 15, were tested in a Caco-2 assay and showed good permeability and low efflux, suggesting high potential for oral bioavailability.

Inducible Nitric Oxide Synthase as a Possible Target in Hypertension

Nitric oxide (NO) is an important vasodilator produced by vascular endothelium. Its enzymatic formation is derived from three different synthases: neuronal (nNOS), endothelial (eNOS) and inducible (iNOS) synthases. While relatively small amounts of NO produced by eNOS are important to cardiovascular homeostasis, high NO levels produced associated with iNOS activity may have detrimental consequences to the cardiovascular system and contribute to hypertension. In this article, we reviewed current literature and found mounting evidence indicating that increased iNOS expression and activity contribute to the pathogenesis of hypertension and its complications. Excessive amounts of NO produced by iNOS up-regulation can react with superoxide anions forming peroxynitrite, thereby promoting nitrosative stress and endothelial dysfunction. In addition, abnormal iNOS activity can up-regulate arginase activity, allowing it to compete with eNOS for L-arginine, thereby resulting in reduced NO bioavailability. This may also lead to eNOS uncoupling with enhanced production of superoxide anions instead of NO. All these alterations mediated by iNOS apparently contribute to hypertension and its complications. We also reviewed current evidence showing the effects of iNOS inhibitors on different animal models of hypertension. iNOS inhibition apparently exerts antihypertensive effects, decreases oxidative and nitrosative stress, and improves vascular function. Together, these studies highlight the possibility that iNOS is a potential pharmacological target in hypertension.

A novel liposomal nanomedicine for nitric oxide delivery and breast cancer treatment

Breast cancer is the most common type of cancer occurring among women in the United States. Nitric oxide (NO) is endogenous signaling molecules that regulate biological processes. NO has the potential to induce either cancer progression or cancer cell apoptosis depending on intra-tumoral NO concentration. High levels of NO have a cytotoxic effect on cancer cells. A novel cytotoxic gas delivery system has been developed using NO-loaded echogenic liposomes (ELIP) for breast cancer treatment. Empty ELIP and NO-ELIP were prepared using the previously developed freezing-under-pressure method with modified lipid composition. Echogenicity of NO-ELIP was measured to determine the stability of NO-ELIP. Two types of breast cancer cell (BCC) lines, MDA-MB-231 and MDA-MB-468, were utilized. MTT assay was performed after NO-ELIP treatment to determine BCC viability. Echogenicity data demonstrated improved stability of NO-ELIP with the use of BSA for resuspension of NO-ELIP. Cell death induced by NO-ELIP was not from lipid cytotoxicity but from NO. The cytotoxic effect of NO-ELIP on BCC was highly dependent on NO-ELIP concentration. NO-ELIP in concentration of 1.0-2.0 mg/ml induced dramatically decreased BCC viability. This novel cytotoxic gas delivery nanomedicine using liposomal carriers, NO-ELIP, has the potential to provide improved therapeutic effect for breast cancer treatment.