Nitric oxide

Fluorescent small molecule donors

Small molecule donors (SMDs) play subtle roles in the signaling mechanism and disease treatments. While many excellent SMDs have been developed, dosage control, targeted delivery, spatiotemporal feedback, as well as the efficiency evaluation of small molecules are still key challenges. Accordingly, fluorescent small molecule donors (FSMDs) have emerged to meet these challenges. FSMDs enable controllable release and non-invasive real-time monitoring, providing significant advantages for drug development and clinical diagnosis. Integration of FSMDs with chemotherapeutic, photodynamic or photothermal properties can take full advantage of each mode to enhance therapeutic efficacy. Given the remarkable properties and the thriving development of FSMDs, we believe a review is needed to summarize the design, triggering strategies and tracking mechanisms of FSMDs. With this review, we compiled FSMDs for most small molecules (nitric oxide, carbon monoxide, hydrogen sulfide, sulfur dioxide, reactive oxygen species and formaldehyde), and discuss recent progress concerning their molecular design, structural classification, mechanisms of generation, triggered release, structure-activity relationships, and the fluorescence response mechanism. Firstly, from the large number of fluorescent small molecular donors available, we have organized the common structures for producing different types of small molecules, providing a general strategy for the development of FSMDs. Secondly, we have classified FSMDs in terms of the respective donor types and fluorophore structures. Thirdly, we discuss the mechanisms and factors associated with the controlled release of small molecules and the regulation of the fluorescence responses, from which universal guidelines for optical properties and structure rearrangement were established, mainly involving light-controlled, enzyme-activated, reactive oxygen species-triggered, biothiol-triggered, single-electron reduction, click chemistry, and other triggering mechanisms. Fourthly, representative applications of FSMDs for trackable release, and evaluation monitoring, as well as for visible in vivo treatment are outlined, to illustrate the potential of FSMDs in drug screening and precision medicine. Finally, we discuss the opportunities and remaining challenges for the development of FSMDs for practical and clinical applications, which we anticipate will stimulate the attention of researchers in the diverse fields of chemistry, pharmacology, chemical biology and clinical chemistry. With this review, we hope to impart new understanding thereby enabling the rapid development of the next generation of FSMDs.

Chemical composition and anti-inflammatory activity of flower essential oil from Forsythia koreana Nakai

Forsythia koreana Nakai is an ornamental plant widely cultivated in East Asia. The essential oil of F. koreana flowers (FEO) was extracted by hydrodistillation process and the volatile components were determined with gas chromatography coupled with mass spectrometry. The anti-inflammatory activity of FEO was investigated by using TPA-induced mouse ear inflammation model. The major components of FEO were identified as n-tetracosane (29.85%), n-heneicosane (17.45%), myristic acid (8.46%) and palmitaldehyde (6.22%). The TPA-induced mouse ear edema, water content, dermis thickness, epidermis thickness and nitric oxide production were decreased by FEO. Our findings suppose that the flower essential oil of F. koreana exerted anti-inflammatory activity, and may be used in the development of anti-inflammatory products in future.

MXene-Derived Metal-Organic Framework@MXene Heterostructures toward Electrochemical NO Sensing

The electrochemical sensing of nitric oxide (NO) molecules by metal-organic framework (MOF) catalysts has been impeded, to a large extent, owing to their poor electrical conductivity and weak NO adsorption. In this work, incomplete in situ conversion of V₂ CT_x (T = terminal atoms) MXene to MOF is adopted, forming MOF@MXene heterostructures, which outperform MXene and MOF monocomponents toward electrochemical NO sensing. Density functional theory (DFT) calculation results indicate metal-like electronic characters for the heterostructure benefiting from the dominating contribution of the V 3d orbitals of the metallic MXene. Moreover, plane-averaged charge density difference shows substantial charge redistribution occurs at the heterointerfaces, producing a built-in field, which facilitates charge transfer. Besides, molecular mechanics-based simulated annealing calculation reveals greatly enhanced adsorption energies of NO molecules on the heterointerfaces than that on separate MOFs and MXenes. Hence, the facilitated charge transfer and preferential NO adsorption are responsible for the dramatically promoted performance toward NO sensing. The prudent design of MOF@MXene heterostructure may spur advanced electrocatalysts for electrochemical sensing.

An Overview of Circulating Pulmonary Arterial Hypertension Biomarkers

Pulmonary arterial hypertension (PAH), also known as Group 1 Pulmonary Hypertension (PH), is a PH subset characterized by pulmonary vascular remodeling and pulmonary arterial obstruction. PAH has an estimated incidence of 15-50 people per million in the United States and Europe, and is associated with high mortality and morbidity, with patients' survival time after diagnosis being only 2.8 years. According to current guidelines, right heart catheterization is the gold standard for diagnostic and prognostic evaluation of PAH patients. However, this technique is highly invasive, so it is not used in routine clinical practice or patient follow-up. Thereby, it is essential to find new non-invasive strategies for evaluating disease progression. Biomarkers can be an effective solution for determining PAH patient prognosis and response to therapy, and aiding in diagnostic efforts, so long as their detection is non-invasive, easy, and objective. This review aims to clarify and describe some of the potential new candidates as circulating biomarkers of PAH.

The Breast Cancer Protooncogenes HER2, BRCA1 and BRCA2 and Their Regulation by the iNOS/NOS2 Axis

The expression of inducible nitric oxide synthase (iNOS; NOS2) and derived NO in various cancers was reported to exert pro- and anti-tumorigenic effects depending on the levels of expression and the tumor types. In humans, the breast cancer level of iNOS was reported to be overexpressed, to exhibit pro-tumorigenic activities, and to be of prognostic significance. Likewise, the expression of the oncogenes HER2, BRCA1, and BRCA2 has been associated with malignancy. The interrelationship between the expression of these protooncogenes and oncogenes and the expression of iNOS is not clear. We have hypothesized that there exist cross-talk signaling pathways between the breast cancer protooncogenes, the iNOS axis, and iNOS-mediated NO mutations of these protooncogenes into oncogenes. We review the molecular regulation of the expression of the protooncogenes in breast cancer and their interrelationships with iNOS expression and activities. In addition, we discuss the roles of iNOS, HER2, BRCA1/2, and NO metabolism in the pathophysiology of cancer stem cells. Bioinformatic analyses have been performed and have found suggested molecular alterations responsible for breast cancer aggressiveness. These include the association of BRCA1/2 mutations and HER2 amplifications with the dysregulation of the NOS pathway. We propose that future studies should be undertaken to investigate the regulatory mechanisms underlying the expression of iNOS and various breast cancer oncogenes, with the aim of identifying new therapeutic targets for the treatment of breast cancers that are refractory to current treatments.

Evaluation of the effects produced by subacute tributyltin administration on vascular reactivity of male wistar rats

Tributyltin chloride (TBT) is an organotin compound widely used in several high biocides for agroindustrial applications, such as fungicides, and marine antifouling paints leading to endocrine disrupting actions, such as imposex development in mollusks. In female rats, TBT has been shown to promote ovarian dysfunction, reduction of estrogen protective effect in the vascular morphophysiology, at least in part by oxidative stress consequences. Estrogen causes coronary endothelium-dependent and independent vasodilation. However, the TBT effects on cardiovascular system of male rats are not fully understood. The aim of this study was to evaluate the effects of subacute TBT exposure in aorta vascular reactivity from male wistar rats. Rats were randomly divided into three groups: control (C), TBT 500 ng/kg/day and TBT 1000 ng/kg/day. TBT was administered daily for 30 days by oral gavage. We found that TBT exposure enhanced testosterone serum levels and it was also observed obesogenic properties. TBT exposure evoked an increase in endothelium-dependent and independent phenylephrine-induced contraction, associated to an inhibition in eNOS activity. On the other hand, it was observed an enhancement of iNOS and NF-kB protein expression. We also observed an increase in oxidative stress parameters, such as superoxide dismutase (SOD) and catalase expression, and also an increase in malondialdehyde production. Finally, TBT exposure produced aortic intima-media thickness. Taken together, these data suggest a potential cardiovascular toxicological effect after subacute TBT exposure in male rats.

Ameliorative role of inducible nitric oxide synthase inhibitors against sodium arsenite-induced renal and hepatic dysfunction in rats

Arsenic exposure causes immense health distress by increasing risk of cardiovascular abnormalities, diabetes mellitus, neurotoxicity, and nephrotoxicity. The present study explored the role of inducible nitric oxide synthase (iNOS) inhibitors against sodium arsenite-induced renal and hepatic dysfunction in rats. Female Sprague Dawley rats were subjected to arsenic toxicity by administering sodium arsenite (5 mg/kg/day, oral) for 4 weeks. The iNOS inhibitors, S-methylisothiourea (10 mg/kg, i.p.) and aminoguanidine (100 mg/kg, i.p.) were given one hour before sodium arsenite administration in rats for 4 weeks. Sodium arsenite led rise in serum creatinine, urea, uric acid, electrolytes (potassium, fractional excretion of sodium), microproteinuria, and decreased creatinine clearance (p < 0.001) indicated renal dysfunction in rats. Arsenic-intoxication resulted in significant oxidative stress in rat kidneys, which was measured in terms of increase in lipid peroxides, superoxide anion generation and decrease in reduced glutathione (p < 0.001) levels. A threefold increase in renal hydroxyproline level in arsenic intoxicated rats indicated fibrosis. Hematoxylin-eosin staining indicated tubular damage, whereas picrosirius red staining highlighted collagen deposition in rat kidneys. S-methylisothiourea and aminoguanidine improved renal function and attenuated arsenic led renal oxidative stress, fibrosis, and decreased the kidney injury score. Additionally, arsenite-intoxication resulted in significant rise in hepatic parameters (serum aspartate aminotransferase, alanine transferase, alkaline phosphatase, and bilirubin (p < 0.001) along with multi-fold increase in oxidative stress, fibrosis and liver injury score in rats, which was significantly (p < 0.001) attenuated by concurrent administration of iNOS inhibitors). Hence, it is concluded that iNOS inhibitors attenuate sodium arsenite-induced renal and hepatic dysfunction in rats.

Eucalyptus robusta leaves methanolic extract suppresses inflammatory mediators by specifically targeting TLR4/TLR9, MPO, COX2, iNOS and inflammatory cytokines in experimentally-induced endometritis in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Bacterial endometritis is one of the major causes of reproductive disorders including infertility in farm animals. Antibiotics are generally used for treatment of such disorders but now a days residues of antibiotics are of great public health concern, therefore, phytoremediation is being considered as an alternative to use of antibiotics.

AIM OF THE STUDY

Present study was undertaken to investigate the efficacy of Eucalyptus robusta leaves methanolic extract against endometritis along with the possible mechanism of action especially targeting inflammatory biomarkers.

MATERIALS AND METHODS

Bacterial endometritis was produced using clinical isolates of E. coli and Staphyloccocus aureus from bovines (cows and buffaloes) endometritis cases. After seven days of inoculation of the mixed bacterial culture, endometritis was confirmed based on the presence of visible pus and edema, thinning of endometrial lining and presence of large number of polymorphonuclear cells and bacterial load in uterine flushing. Female Wistar rats were divided in to five groups namely control, sham-operated, endometritis, endometritis plus Eucalyptus leaves extract and endometritis plus cefixime. Serum specific inflammatory biomarkers (interleukin-1β, interleukin-10, tumor necrosis factor-α, intercellular adhesion molecule-1, serum amyloid A) and myleoperoxidase, toll like receptors-4 and -9, inducible nitric oxide synthase, nitric oxide, cyclooxygenase 1 and 2 were estimated in uterine tissues using ELISA kits.

RESULTS

Interleukin-10, serum amyloid A, myleoperoxidase, toll like receptors-4 and-9, cyclooxygenase-2, inducible nitric oxide synthase and nitric oxide were significantly increased while non significant increase in interleukin-1β, cycloxygenase-1 and intercellular adhesion molecule-1 were observed but level of tumor necrosis factor-α was found decreased in rats of endometritis group. Histopathological lesions in uterus showed efficient induction of endometritis by presence of inflammatory cells which are lessened effectively after treatment with Eucalyptus leaves extract. Eucalyptus robusta leaves extract produced curative and protective effect against endometritis and results were comparable to or even better than cefixime.

CONCLUSIONS

Eucalyptus robusta leaves extract possess promising antibacterial activity and efficacy against experimental endometritis and, therefore, holds promising potential for development of effective formulation for treatment of endometritis in animals.

Inflammation Enhances the Risks of Stroke and Death in Chronic Chagas Disease Patients

Ischemic strokes have been implicated as a cause of death in Chagas disease patients. Inflammation has been recognized as a key component in all ischemic processes, including the intravascular events triggered by vessel interruption, brain damage and repair. In this study, we evaluated the association between inflammatory markers and the death risk (DR) and stroke risk (SR) of patients with different clinical forms of chronic Chagas disease. The mRNA expression levels of cytokines, transcription factors expressed in the adaptive immune response (Th1, Th2, Th9, Th17, Th22 and regulatory T cell), and iNOS were analyzed by real-time PCR in peripheral blood mononuclear cells of chagasic patients who exhibited the indeterminate, cardiac, digestive and cardiodigestive clinical forms of the disease, and the levels of these transcripts were correlated with the DR and SR. Cardiac patients exhibited lower mRNA expression levels of GATA-3, FoxP3, AHR, IL-4, IL-9, IL-10 and IL-22 but exhibited higher expression of IFN-γ and TNF-α compared with indeterminate patients. Digestive patients showed similar levels of GATA-3, IL-4 and IL-10 than indeterminate patients. Cardiodigestive patients exhibited higher levels of TNF-α compared with indeterminate and digestive patients. Furthermore, we demonstrated that patients with high DR and SR exhibited lower GATA-3, FoxP3, and IL-10 expression and higher IFN-γ, TNF-α and iNOS mRNA expression than patients with low DR and SR. A negative correlation was observed between Foxp3 and IL-10 mRNA expression and the DR and SR. Moreover, TNF-α and iNOS expression was positively correlated with DR and SR. Our data suggest that an inflammatory imbalance in chronic Chagas disease patients is associated with a high DR and SR. This study provides a better understanding of the stroke pathobiology in the general population and might aid the development of therapeutic strategies for controlling the morbidity and mortality of Chagas disease.

Estresse oxidativo e a função endotelial: efeitos do exercício físico associado à lipemia pós-prandial

Resumo Estratégias que possam prevenir o aparecimento da aterosclerose são de extrema importância para a saúde pública. O aumento da lipemia pós-prandial tem sido investigado, dentre os fatores de risco modificáveis para o desenvolvimento dessa doença, pois pode induzir dano oxidativo e disfunção endotelial. Nesse sentido, o exercício físico é indicado na prevenção do desenvolvimento desses fatores de risco. Esta revisão tem como objetivo realizar um levantamento e comparar os estudos publicados na literatura acerca dos efeitos agudos e subagudos do exercício físico associado à lipemia pós-prandial sobre o estresse oxidativo e a função endotelial. A busca foi realizada nos idiomas português, espanhol e inglês, compreendendo trabalhos publicados até fevereiro de 2015. Com base nos estudos selecionados, conclui-se que os efeitos agudos e subagudos do exercício físico podem ser capazes de atenuar os parâmetros de risco cardiovascular após o consumo de refeição hiperlipídica.

Evaluation of Serum Homocysteine and Leptin Levels in Patients with Uveitis

OBJECTIVES

To evaluate the serum homocysteine (Hcy) and leptin levels in patients with uveitis.

MA­TE­RI­ALS AND MET­HODS

The 70 cases included in the study comprised 3 groups: patients with Behçet's uveitis (BU), patients with non-Behçet's uveitis (NBU) and healthy controls. Body mass index was calculated for each subject. Serum Hcy and leptin levels were measured. Furthermore, acute-phase reactants including erythrocyte sedimentation rate (ESR), C-reactive protein and neutrophil count were measured.

RE­SULTS

Serum Hcy levels were 15.04±4.59 µmol/L in the BU group, 15.4±6.87 µmol/L in the NBU group and 13.64±4.72 µmol/L in the control group (p>0.05). The serum leptin levels of male patients in the BU group, NBU group and control group were 4.76±3.54 ng/ml, 6.33±3.74 ng/ml and 5.47±6.33 ng/ml, respectively (p>0.05). When we compared serum leptin levels in female patients and controls, the mean serum leptin concentrations were significantly higher in female BU and NBU patients (24.83±17.62 ng/ml and 28.46±13.90 ng/ml, respectively) than in healthy control volunteers (9.62±6.36 ng/ml, p<0.05). In addition, the ESR value differences between groups were statistically significant (p<0.05).

CONCLUSION

A larger case series is necessary to investigate serum Hcy and leptin concentrations in uveitis patients.

Susceptibility of bone marrow-derived macrophages to influenza virus infection is dependent on macrophage phenotype

The role of the macrophage in influenza virus infection is complex. Macrophages are critical for resolution of influenza virus infections but implicated in morbidity and mortality in severe infections. They can be infected with influenza virus and consequently macrophage infection is likely to have an impact on the host immune response. Macrophages display a range of functional phenotypes, from the prototypical pro-inflammatory classically activated cell to alternatively activated anti-inflammatory macrophages involved in immune regulation and wound healing. We were interested in how macrophages of different phenotype respond to influenza virus infection and therefore studied the infection of bone marrow-derived macrophages (BMDMs) of classical and alternative phenotype in vitro. Our results show that alternatively activated macrophages are more readily infected and killed by the virus than classically activated. Classically activated BMDMs express the pro-inflammatory markers inducible nitric oxide synthase (iNOS) and TNF-α, and TNF-α expression was further upregulated following infection. Alternatively activated macrophages express Arginase-1 and CD206; however, following infection, expression of these markers was downregulated whilst expression of iNOS and TNF-α was upregulated. Thus, infection can override the anti-inflammatory state of alternatively activated macrophages. Importantly, however, this results in lower levels of pro-inflammatory markers than those produced by classically activated cells. Our results showed that macrophage phenotype affects the inflammatory macrophage response following infection, and indicated that modulating the macrophage phenotype may provide a route to develop novel strategies to prevent and treat influenza virus infection.

Malvidin-3-O-β glucoside, major grape anthocyanin, inhibits human macrophage-derived inflammatory mediators and decreases clinical scores in arthritic rats

Polyphenolic anthocyanins are major colorful compounds in red fruits, known to prevent cardiovascular and other diseases. Grape polyphenols are a mixture of various molecules and their exact contribution to above bioactivities remains to be clarified. In the present study, we first analyzed the effect of purified grape-derived compounds on human peripheral blood mononuclear cell (PBMC) survival, proliferation, as well as for their ability to inhibit the activation of human normal macrophages. Data indicated that malvidin-3-O-β glucoside (Malβg), the major grape anthocyanin, is bioactive with no toxicity on human PBMC. Malβg decreased the transcription of genes encoding inflammatory mediators, confirmed by the inhibition of TNFα, IL1, IL-6 and iNOS-derived nitric oxide (NO) secretion from activated macrophages. As Malβg also inhibited inflammatory response of rat macrophages, we investigated the anti-inflammatory potential of Malβg in chronic rat adjuvant-induced arthritis (AIA). Malβg significantly diminished inflammatory cachexia and arthritic paw scores in AIA rats at both therapeutic and preventive levels. In vivo effects of Malβg correlated with down-regulation of NO generation from AIA rats' peritoneal macrophages ex vivo. These data indicate that Malβg, major grape anthocyanin, is a potent anti-inflammatory agent in vitro and in vivo, without detectable toxic effect.

Low-energy extracorporeal shock wave therapy enhances skin wound healing in diabetic mice: a critical role of endothelial nitric oxide synthase

Low-energy extracorporeal shock wave (LE-ESW) treatment has been shown to accelerate wound repair; however, the mechanisms of treatment remain unclear. In the present study, we addressed the role of endothelial nitric oxide synthase (eNOS). A single LE-ESW treatment accelerated the healing of wounds in diabetic mice caused by the injection of streptozotocin. This accelerated healing was accompanied by the increased expression of eNOS and vascular endothelial growth factor (VEGF) and the generation of new vessels at the wound tissues. These results raised the possibility that eNOS may be involved in the beneficial effects of LE-ESW treatment. To address this possibility, we compared the effects of this treatment between mice with a genetic disruption of eNOS knockout (eNOS-KO mice) and wild-type (WT) control mice. Interestingly, the LE-ESW-induced acceleration of wound closure and the increase in VEGF expression and neovascularization was significantly attenuated in eNOS-KO mice compared with WT mice. Considered collectively, these results showed that eNOS was induced at the wound tissues by LE-ESW treatment and played a critical role in the therapeutic effects of this treatment by accelerating the wound healing by promoting VEGF expression and neovascularization.

Oxidative stress markers are increased since early stages of infection in syphilitic patients

Clinical symptoms of syphilis are the consequence of the spirochete propensity to induce persistent chronic inflammation, which could participate to oxidative stress increase. The present study was designed to evaluate the level of oxidative stress biomarkers and antioxidant defences in a cohort of syphilitic patients. Serum oxidative status was explored in 63 patients diagnosed with early syphilis, 34 consulting patients negative for syphilis and 19 healthy controls. Total plasma thioredoxin (Trx) and thiols were determined as antioxidant capacity markers, °NO, advanced oxidation protein products (AOPP) and protein carbonyl levels as oxidative stress status biomarkers, and CRP as marker of inflammation. Mean serum levels of Trx, AOPP, carbonyls, and nitrates/nitrites were significantly higher, whereas thiols level was lower in syphilitic patients compared to non-syphilitic patients and healthy controls (respectively, p < 0.05/p < 0.01 for Trx, p < 0.005/p < 0.0001 for AOPP, p < 0.05/p < 0.005 for carbonyls, p < 0.005/p < 0.05 for nitrates/nitrites and p < 0.01/p < 0.0001 for thiols). According to the stage of the disease, results highlighted a marked and sustained oxidative stress imbalance from the first stage to the latent period of the disease. Moreover, syphilitic patients presented a low inflammation status reflected by median of CRP level (1.7 mg/L, range 5th-95th percentile from <0.1 to 33.7 mg/L), correlated with antioxidant capacity decrease (thiols) at stage 1 (r = -0.725; p < 0.0001) and nitrosative stress increase (nitrates/nitrites) at stage 2 and latent (respectively, r = 0.285, p < 0.05 and r = 0.650, p < 0.05). These findings indicate that at all stages of the disease, despite a low-grade inflammatory state, syphilis infection generates a major oxidative and nitrosative stress which may be involved in the pathophysiology of the disease.

Ocular Behçet disease: current therapeutic approaches

PURPOSE OF REVIEW

To alert physician to timely recognition and current treatment of recurrent hypopyon iridocyclitis or panuveitis in ocular Behçet disease (OBD).

RECENT FINDINGS

Interferon-α, rituximab, intravitreal triamcinolone, and biological response modifiers by tumor necrosis factor inhibitors such as infliximab and adalimumab are being used increasingly for the treatment of severe sight-threatening ocular inflammation including retinal vasculitis and cystoid macular edema (CME).

SUMMARY

Biological agents offer tremendous potential in the treatment of OBD. Given that OBD predominantly afflicts the younger adults in their most productive years, dermatologist, rheumatologist, internist, or general practitioners supervising patients with oculo-articulo-oromucocutaneous syndromes should be aware of systemic Behçet disease. Early recognition of ocular involvement is important and such patients should strongly be instructed to visit immediately an ophthalmologist, as uveitis management differs from extraocular involvements with high ocular morbidity from sight-threatening complications due to relapsing inflammatory attacks in the posterior segment of the eye. A single infliximab infusion should be considered for the control of acute panuveitis, whereas repeated long-term infliximab infusions were proved to be more effective in reducing the number of episodes in refractory uveoretinitis with faster regression and complete remission of CME.

Parallel effects of β-adrenoceptor blockade on cardiac function and fatty acid oxidation in the diabetic heart: Confronting the maze

Diabetic cardiomyopathy is a disease process in which diabetes produces a direct and continuous myocardial insult even in the absence of ischemic, hypertensive or valvular disease. The β-blocking agents bisoprolol, carvedilol and metoprolol have been shown in large-scale randomized controlled trials to reduce heart failure mortality. In this review, we summarize the results of our studies investigating the effects of β-blocking agents on cardiac function and metabolism in diabetic heart failure, and the complex inter-related mechanisms involved. Metoprolol inhibits fatty acid oxidation at the mitochondrial level but does not prevent lipotoxicity; its beneficial effects are more likely to be due to pro-survival effects of chronic treatment. These studies have expanded our understanding of the range of effects produced by β-adrenergic blockade and show how interconnected the signaling pathways of function and metabolism are in the heart. Although our initial hypothesis that inhibition of fatty acid oxidation would be a key mechanism of action was disproved, unexpected results led us to some intriguing regulatory mechanisms of cardiac metabolism. The first was upstream stimulatory factor-2-mediated repression of transcriptional master regulator PGC-1α, most likely occurring as a consequence of the improved function; it is unclear whether this effect is unique to β-blockers, although repression of carnitine palmitoyltransferase (CPT)-1 has not been reported with other drugs which improve function. The second was the identification of a range of covalent modifications which can regulate CPT-1 directly, mediated by a signalome at the level of the mitochondria. We also identified an important interaction between β-adrenergic signaling and caveolins, which may be a key mechanism of action of β-adrenergic blockade. Our experience with this labyrinthine signaling web illustrates that initial hypotheses and anticipated directions do not have to be right in order to open up meaningful directions or reveal new information.

The association of receptor of advanced glycated end products and inflammatory mediators contributes to endothelial dysfunction in a prospective study of acute kidney injury patients with sepsis

The pathogenesis of acute kidney injury (AKI) occurring due to sepsis is incompletely understood. Endothelial activation, defined as up-regulation of adhesion molecules by proinflammatory cytokines, may be central to the development of sepsis-induced AKI. Our aim was to determine levels of circulating adhesion molecules endothelial (E)-selectin, intercellular adhesion molecule (ICAM), and vascular cell adhesion molecule (VCAM), inflammatory mediators; tumor necrosis factor-α (TNF-α) and transforming growth factor-β (TGF-β), vasoactive mediators; endothelin-1 (ET-1) and nitric oxide (NO), soluble receptor for advanced glycated end products (sRAGE) and serum fetuin-A in septic AKI patients before and after antibiotic therapy. Nineteen AKI patients with sepsis and fifteen healthy controls were enrolled in this prospective study. Results revealed that 12 weeks of therapy caused amelioration of endothelial and inflammatory injuries as well as renal function markers. Moreover, the positive correlations between levels of RAGE and E-selectin (r=0.88), ET-1 (r=0.90), and TNF-α (r=0.94) and negative with NO (r=-0.75-0.95) suggest that possible interaction of RAGE and inflammation may contribute to endothelial dysfunction in septic AKI patients.

Nitric oxide: a new biomarker of Doxorubicin toxicity in children?

Doxorubicin (DOX) has been used in the treatment of childhood cancers, but its usage is limited because of cardiotoxicity. There are many studies on the role of nitric oxide (NO) in several cardiac diseases. However, to the authors' knowledge, no studies have investigated the plasma levels of total nitrite, a stable product of NO, in children that received DOX. The authors determined plasma total nitrite levels in 29 children who received DOX and investigated the correlations between these and other clinical and laboratory findings. All patients were in remission during the study period. Plasma total nitrite levels and cardiac functions were determined prospectively. The mean cumulative DOX dose was 310.0 ± 90.9 mg/m(2). In echocardiographic evaluation, 3 patients (10.3%) had a pathological value for ejection fraction (EF) and/or fractional shortening (FS), whereas 11 patients (37.9%) had a threshold value. Total nitrite levels were higher in patients than in matched controls (75.24 ± 39.4 vs 43.14 ± 10.58 μmol/L, respectively, P < .001). It was also found to be higher in patients who had a pathological/threshold value of EF and FS than in patients who had a physiological value of EF and FS (92.35 ± 50.36 vs 59.26 ± 13.56 μmol/L, respectively, P = .038). A negative correlation was found between FS and plasma total nitrite level (r = -.42, P = .023). The authors speculate that increased NO may be a sign of subclinical cardiotoxicity of DOX.

Nitric oxide synthases, cyclooxygenase-2, nitrotyrosine, and angiogenesis in chondrosarcoma and their relation to prognosis

BACKGROUND

The localization in tumor tissue of various markers by immunohistochemistry can help to establish a diagnosis or predict prognosis. Nitric oxide is associated with tumors and has been studied indirectly by nitrotyrosine analysis and with use of the enzymes nitric oxide synthase (NOS)1, NOS2, and NOS3. Nitric oxide reacts with superoxide anions to yield peroxynitrite, which has toxic effects on genes. Peroxynitrite adds a nitro group to the benzene ring of tyrosine to form nitrotyrosine. The accumulation of nitrotyrosine, a stable product in cells, indicates the formation of peroxynitrite. Nitric oxide stimulates the production of cyclooxygenase-2 (COX-2), which has been associated with angiogenesis in tumors. Neovascularization influences tumor prognosis, as demonstrated by microvessel studies with use of CD34, an immunohistochemical endothelial cell marker. This study examines the expression of these markers in chondrosarcomas and their relation to histological grade and prognosis.

METHODS

Tissue microarrays composed of formalin-fixed tissue samples from 101 patients with chondrosarcoma were immunohistochemically stained to localize NOS1, NOS2, NOS3, COX-2, nitrotyrosine, and CD34. Five samples of normal cartilage were used as controls. Patient demographics, selected surgical variables, and tumor grade were tabulated, and the associations were analyzed. Analyses of local and overall survival rates were performed with use of the Kaplan-Meier method, and multivariable analyses were performed.

RESULTS

There was a significant association of nitrotyrosine, COX-2, and CD34 with histological grades (p = 0.022, p = 0.014, and p = 0.028, respectively), but not with overall prognosis (p = 0.064, p = 0.143, and p = 0.581, respectively). The presence of NOS2 was associated with a lower rate of local disease-free survival (p = 0.038), and positive expressions of NOS1 and NOS2 were associated with decreased overall survival rates (p = 0.007 and p < 0.001, respectively). On multivariable analysis, NOS2 expression demonstrated an independent prognostic impact on local disease-free survival; NOS1 and NOS2 expression was a dependent variable, and their isolated or combined expression was related to lower overall survival rates (p = 0.046 and p = 0.004) (hazard ratio, 3.17 [95% confidence interval, 1.0 to 9.8] and 5.58 [95% confidence interval, 1.7 to 18.0], respectively).

CONCLUSIONS

Immunohistochemical markers may have an independent value in predicting the prognosis for patients with chondrosarcoma.

Kidney is in trouble with mediators

The kidneys receive 20-25 % of cardiac output and play a main role in the control of cardiovascular homeostasis. It is an endocrine organ that regulates and produces many substances, scavenger particles and immune complexes. Cytokines, growth factors, reactive oxygen metabolites, bioactive lipids, proteases, vasoactive substances such as nitric oxide (NO), adrenomedullin (AM), urotensin-II (U-II), have been released in several diseases, and kidney is one of mostly affected organs in body. Some of these mediators act in a paracrine fashion while some act in autocrine. They play important roles in modulating the cardiovascular responses, renal hemodynamics, and probably in mediating the clinical and laboratory manifestations of several renal diseases. These mediators are like "a double edged sword". While small amounts of them mediate many physiological events, little excess may cause the damage to the healthy cells. Many investigators have searched the role(s) of mediators in several diseases. However, the findings are mostly like the model of "chicken and egg", and indistinguishable as to whether they are the causes of, or results of the diseases. We will discuss mainly the possible roles of NO, AM and U-II in children with several renal diseases and summarize what is known, and what must be known about these mediators.

Nitrite as regulator of hypoxic signaling in mammalian physiology

In this review we consider the effects of endogenous and pharmacological levels of nitrite under conditions of hypoxia. In humans, the nitrite anion has long been considered as metastable intermediate in the oxidation of nitric oxide radicals to the stable metabolite nitrate. This oxidation cascade was thought to be irreversible under physiological conditions. However, a growing body of experimental observations attests that the presence of endogenous nitrite regulates a number of signaling events along the physiological and pathophysiological oxygen gradient. Hypoxic signaling events include vasodilation, modulation of mitochondrial respiration, and cytoprotection following ischemic insult. These phenomena are attributed to the reduction of nitrite anions to nitric oxide if local oxygen levels in tissues decrease. Recent research identified a growing list of enzymatic and nonenzymatic pathways for this endogenous reduction of nitrite. Additional direct signaling events not involving free nitric oxide are proposed. We here discuss the mechanisms and properties of these various pathways and the role played by the local concentration of free oxygen in the affected tissue.

Vitamin levels in Behçet's disease

OBJECTIVE

To determine the role of oxidative stress and the antioxidant defense mechanism in the etiopathogenesis of active and inactive Behçets disease. In line with this objective, the present study aimed to examine the levels of nitric oxide (NO) and malondialdehyde (MDA), which are the end products of oxidant stress, and vitamins, which are non-enzymatic antioxidants, for the diagnosis and particularly the follow-up of Behçet's disease.

MATERIALS AND METHODS

The study group consisted of a total of 60 individuals: 40 of whom were Behçet's disease patients and 20 were healthy individuals. Of the 40 Behçet's patients, 29 had the active and 11 had the inactive (stable) form of the disease.

RESULTS

Although plasma MDA and NO (its stable form nitrite) levels in the total patient group were statistically significantly higher than those in the control group (p<0.06), there was no statistically significant difference as such between inactive Behçet's patients and the control group (p>0.05). Vitamin E, C, B1, B2 and flavin mononucleotide (FMN) values were significantly lower in the patient group in comparison with the control group (p<0.05). There was no statistically significant difference in other vitamin values.

DISCUSSION

It is contemplated that measurement of such oxidative stress factors as MDA and NO and an accompanying evaluation of the antioxidant defense system can be significant in the diagnosis and treatment follow-up of Behçet's disease.

Urinary nitric oxide levels are increased and correlated with plasma concentrations in patients with Behçet's disease: is it a new urinary activity marker?

Nitric oxide (NO) is a free radical and serves many functions within the kidney. Excess NO causes glomerular injury. Behçet's disease (BD) is a systemic immunoinflammatory vasculitis, affecting every organ in the body including the kidneys (subclinic glomerulonephritis). We investigated the role of urinary total nitrite levels (end product of NO) in BD and evaluated whether urinary concentrations were correlated with its plasma levels or disease activity. Thirty-six consecutive Behçet's patients (19 men, 17 women; 35.9 years), and 20 age- and sex-matched healthy control volunteers (12 men, eight women; 33.2 years) were divided into an active (n = 16) and inactive (n = 20) period. Urinary and serum NO levels ( micromol/mg urinary creatinine) were higher in BD patients (4.1 +/- 0.3) than control subjects (1.7 +/- 0.2; P < 0.001). Serum NO levels in Behçet's patients and control subjects were 51.3 +/- 9.8 and 21.7 +/- 7.3 micromol/L, respectively (P < 0.001). Active patients had higher urinary NO excretion (4.9 +/- 0.3) than inactive patients (3.3 +/- 0.3; P < 0.01). Urinary NO levels were correlated with its serum levels (r2 = 0.69, P < 0.001). Higher urinary NO levels found in BD may be produced by the kidney as a result of an inflammatory stimulation. As excess NO is toxic to the tissues, increased NO levels may play a role in mediating subclinic glomerular injury of such patients. However, we could not determine the exact site(s) of NO synthesis by the kidney, such as the glomeruli, blood vessels and/or the tubular cells. Whatever the source, urinary NO levels may be used as a new activity marker in the diagnosis and follow up of BD by serial measurements.

Nitric oxide in the human uterine cervix: endogenous ripening factor

The human uterine cervix can produce nitric oxide (NO), a free radical with an ultra-short half-life. The release of NO changes during pregnancy and is increased in early nonviable pregnancies compared to normal uncomplicated pregnancies. This review concentrates on the role of NO release in cervical ripening in pregnant women. Also some suggestions on future aspects are discussed.

Serum and urine nitrite and citrulline levels among patients with systemic lupus erythematosus: a possible addition to activity parameters?

Nitric oxide (NO) plays a significant role in the inflammatory process and has been implicated in several autoimmune disorders. This study was carried out prospectively to estimate the levels of nitrite and citrulline in the serum and urine, as surrogate markers of NO production, among patients with systemic lupus erythematosus (SLE). Forty-seven patients and 44 age- and sex-matched, healthy volunteers were studied. Nitrite and citrulline were measured in serum and urine by spectrophotometry.Median serum nitrite and citrulline levels and urine citrulline levels were higher among patients as compared with controls (p < 0.05). Patients with skin involvement stood out and had higher median serum and urine citrulline levels (p < 0.05). Disease activity correlated with steroid dosage, serum nitrite levels, and serum and urine citrulline levels (p < 0.05). Steroid dosage correlated with serum citrulline level (p < 0.05). Serum and urine citrulline levels correlated with each other (p < 0.01). In the subset of 13 individuals with renal involvement, serum and urine citrulline levels correlated with each other (p < 0.01) as did urine nitrite and citrulline levels (p < 0.05).NO production is increased among patients with SLE, and this increase correlates with disease activity and dosage of steroids used. The addition of a urine test to measure NO production as a marker of disease activity using simple spectrophotometry can be a valuable adjunct to other tests, can obviate the need for drawing a blood sample for this purpose, and can be repeated as often as necessary.

Effects of nitric oxide synthase inhibition on blood flow and survival in experimental skin flaps

The aim of the present study was to examine the effect of the nitric oxide synthase (NOS) inhibitor N(omega)-nitro-l-arginine methyl ester (l-NAME) on skin and flap blood flow, NOS activity and flap survival in an ischaemic dorsal flap model in the rat. Fifty-four rats were used in the study. l-NAME or the inactive enantiomere d-NAME was given intravenously either pre-, per- and postoperatively or only postoperatively. Controls received saline treatment. Blood pressure and skin and flap blood flow were monitored. NOS activity was measured in intact skin before and after l-NAME and d-NAME infusion and in flap tissue 48h postoperatively. Forty-eight hours postoperatively flap survival was determined in all rats. l-NAME treatment caused: (1) a marked attenuation of constitutive Ca(2+) dependent NOS activity in intact skin (p<0.001), (2) an increase in blood pressure (p<0.05), (3) a decrease in blood flow in intact skin and in skin flaps (p<0.05), and (4) a decrease in flap survival (p<0.05). In saline and d-NAME treated animals no change in blood pressure, blood flow or NOS activity in intact skin was noted. In conclusion this study shows that l-NAME attenuates constitutive Ca(2+) dependent NOS activity in intact skin, decreases skin and flap blood flow and decreases the survival of skin flaps. These results indicate that constitutive nitric oxide synthase is important for basal blood flow in skin and flap tissue and for the survival of skin flaps.

Adrenomedullin and total nitrite levels in children with familial Mediterranean fever

AIM

Familial Mediterranean fever (FMF) is the most frequent periodic syndrome characterised by recurrent attacks of polyserositis. However, recent studies revealed that there might be an ongoing subclinical inflammation between the attacks. As nitric oxide (NO) and adrenomedullin (AM) are both synthesised in the endothelium, and mediates many functions within immune system, we considered them to be an interesting target of investigation in FMF.

METHODS

Fifteen children with FMF receiving regular colchicine, ranging in age from 3 to 16 years, were investigated in comparison with 15 healthy age- and sex-matched controls. The mean age of the patients was 9.7 +/- 3.9 years. Total nitrite, a stable product of NO, was quantitated by means of the Griess reaction, while AM was measured by HPLC.

RESULTS

Plasma-urinary AM and total nitrite levels were significantly higher in children with FMF. Plasma AM levels (pmol/mL) in patients and controls were 40.95 +/- 5.99 vs. 34.86 +/- 5.24, P < 0.05, and urinary AM excretion (pmol/mg creatinine) was 51.16 +/- 28.15 vs. 37.5 +/- 24.26, P < 0.05 respectively. Plasma total nitrite levels (micromol/L) in patients and controls were 44.80 +/- 10.36 vs. 32.13 +/- 9.28, P < 0.05, and urinary nitrite excretion (micromol/mg creatinine) was 2.24 +/- 1.71 vs. 1.09 +/- 0.96, P < 0.05 respectively.

CONCLUSION

This study considered that AM and NO may have a role in the immuno-inflammatory process of FMF, although, whether these act to preserve, or protect against, further inflammatory injury is not clear. Our results further supports the hypothesis that these patients have subclinical inflammation between attacks.

Cyclical upregulated iNOS and long-term downregulated nNOS are the bases for relapse and quiescent phases in a rat model of IBD

We previously reported that indomethacin induces a chronic intestinal inflammation in the rat where the cyclical characteristic phases of Crohn's disease are manifested with a few days' interval and lasting for several months: active phase (high inflammation, hypomotility, bacterial translocation) and reactive phase (low inflammation, hypermotility, no bacterial translocation). In this study, we investigated the possible role of both constitutive and inducible isoforms of nitric oxide (NO) synthase (NOS) and cyclooxygenase (COX) in the cyclicity of active and reactive phases in rats with chronic intestinal inflammation. Rats selected at either active or reactive phases and from 2 to 60 days after indomethacin treatment were used. mRNA expression of both constitutive and inducible NOS and COX isoforms in each phase was evaluated by RT-PCR and cellular enzyme localization by immunohistochemistry. The effects of different COX and NOS inhibitors on the intestinal motor activity were tested. mRNA expression of COX-1 was not modified by inflammation, whereas mRNA expression of neuronal NOS was reduced in all indomethacin-treated rats. In contrast, NOS and COX inducible forms showed a cyclical oscillation. mRNA expression and protein of both iNOS and COX-2 increased only during active phases. The intestinal hypomotility associated with active phases was turned into hypermotility after the administration of selective iNOS inhibitors. Sustained downregulation of constitutive NOS caused hypermotility, possibly as a defense mechanism. However, this reaction was masked during the active phases due to the inhibitory effects of NO resulting from the increased levels of the inducible NOS isoform.

The effect of circulating nitric oxide level on axial bone mineral density in postmenopausal Turkish women with rheumatoid arthritis: A preliminary report

The aim is to investigate the differences in the circulating nitric oxide (NO) levels of rheumatoid arthritis (RA) patients, healthy controls and osteoporotic (OP) patients. We also examined whether the circulating NO levels may be correlated with bone mineral density (BMD) in RA patients. Forty-five patients with RA, 30 healthy women and 30 osteoporotic patients were recruited from the outpatient clinic. All the subjects were female and postmenopausal. Serum NO levels were measured (Nitrite/Nitrate, calorimetric method 1746081, Roche diagnostics, Mannheim, Germany) and BMD was measured at the spine and hip using dual energy X-Ray absorbtiometry (DEXA, Norland XR-46). Height and weight were measured and body mass index was calculated. Circulating NO levels were significantly higher in RA patients than other groups. Moreover, the RA group showed significantly higher BMD at lumbar spine and femoral neck regions compared to osteoporotic patients. However, the RA group showed significantly lower BMD at all sites than the controls. There was no correlation between circulating NO levels and BMD in all groups. We suggest that, unlike postmenopausal osteoporosis, inflammation induced osteoporosis is associated with RA is characterised by relatively preserved bone mass at the axial bone regions, and circulating NO levels as a parameter or determinant of inflammation are not correlated with axial BMD in RA patients.

Adrenomedullin and total nitrite levels in children with acute rheumatic fever

OBJECTIVE

To investigate the levels of adrenomedullin (AM) and total nitrite, a stable product of nitric oxide (NO), in children with acute rheumatic fever (ARF).

DESIGN AND METHODS

Eleven children with ARF were investigated in comparison with 14 healthy controls. Adrenomedullin was detected by HPLC, while total nitrite was quantitated by the Griess reaction.

RESULTS

Plasma urinary AM and total nitrite levels were significantly higher in children with ARF, irrespective of whether they were in the acute or convalescent phase of disease. Plasma AM (pmol/mL) levels were 49.19 +/- 3.23 in the acute phase, 44.52 +/- 4.26 in the convalescent phase, 35.49 +/- 3.43 in controls, and urinary AM excretion (pmol/mg creatinine) was 43.45 +/- 18.40 in the acute phase, 32.38 +/- 15.37 in the convalescent phase, and 24.84 +/- 11.38 in controls. Plasma total nitrite levels (mumol/L) were 75.37 +/- 13.13 in the acute phase, 59.81 +/- 12.78 in the convalescent phase, and 41.09 +/- 10.27 in controls. Urinary total nitrite excretion (mumol/mg creatinine) was 3.82 +/- 1.56 in the acute phase, 2.15 +/- 0.58 in the convalescent phase, and 1.33 +/- 0.61 in controls. The differences were statistically significant for all (P < 0.05).

CONCLUSION

This study considered that AM and NO may have a role in the immunoinflammatory process of ARF.

Trichosanthin inhibits antigen-specific T cell expansion through nitric oxide-mediated apoptosis pathway

Trichosanthin (TCS) has been found to exhibit inflammation-suppressing effect but the underlying mechanisms are not clear. In this study, we found that TCS inhibited OVA-specific T cell proliferation in a dose-dependent manner. Such inhibition was correlated with enhanced cell death. At the same time, inducible nitric oxide synthase (iNOS) mRNA expression and protein levels were found increased in cells treated with TCS, and nitric oxide (NO) production by cells was elevated in the presence of TCS. When L-NIL, the specific inhibitor of iNOS, was added to suppress NO production induced by TCS, OVA-specific cell death was significantly inhibited, meanwhile, thymidine incorporation of cells was rescued towards normal levels. These results indicate that TCS could inhibit antigen-specific T cell activation via NO-mediated apoptosis pathway.

Polymorphisms in the endothelial nitric oxide synthase gene are associated with Behçet's disease

OBJECTIVE

Reduced plasma nitric oxide (NO) levels in Behçet's disease (BD) patients have been implicated in the development of the endothelial abnormalities and thrombotic complications occurring in these patients. This study investigated the association of the endothelial NO Synthase (eNOS) gene polymorphisms with BD.

METHODS

A case-control study was carried out using 193 unrelated Turkish BD patients and 106 healthy controls. All individuals were genotyped by PCR for two single-nucleotide polymorphisms (SNPs): -786 T-->C in the promoter region and 894 G-->T in exon 7 (Glu298Asp). A variable number of tandem repeats (VNTR) polymorphism in intron 4 was also investigated.

RESULTS

The VNTR polymorphism was associated with BD, detected by an increased frequency of the b allele (odds ratio = 1.9, P = 0.0069) and b/b genotype (odds ratio = 2.2, P = 0.002) in patients. After the stratification of cases according to the family history, a significant difference between familial cases and controls in the -786 SNP was observed, with an increase in the frequency of the T allele (odds ratio = 2.5, P = 0.0016) and T/T genotype (odds ratio = 2.5, P = 0.0085), and the association of the VNTR polymorphism with BD became stronger. The -786*T and VNTR*b alleles were in linkage disequilibrium (D' = 0.65, P <0.0001), and the number of individuals homozygous for the -786*T/VNTR*b haplotype was significantly increased in the patients.

CONCLUSIONS

eNOS gene polymorphisms are associated with BD, which might contribute to the reduced NO activity observed in BD patients.

The effects of cyclic mechanical strain and tumor necrosis factor alpha on the response of cells of the meniscus

OBJECTIVES

Cells of the knee meniscus respond to changes in their biochemical and biomechanical environments with alterations in the biosynthesis of matrix constituents and inflammatory mediators. Tumor necrosis factor alpha (TNF-alpha) is a pro-inflammatory cytokine that is involved in the pathogenesis of both osteoarthritis and rheumatoid arthritis, but its influence on meniscal physiology or mechanobiology is not fully understood. The objectives of this study were to examine the hypothesis that cyclic mechanical strain of meniscal cells modulates the biosynthesis of matrix macromolecules and pro-inflammatory mediators, and to determine if this response is altered by TNF-alpha.

METHODS

Cells were isolated from the inner two-thirds of porcine medial menisci and subjected to biaxial tensile strain of 5-15% at a frequency of 0.5Hz. The synthesis of proteoglycan, protein, nitric oxide (NO), and prostaglandin E(2) were determined.

RESULTS

Cyclic tensile strain increased the production of nitric oxide through the upregulation of nitric oxide synthase 2 (NOS2) and also increased synthesis rates of prostaglandin E(2), proteoglycan, and total protein in a manner that depended on strain magnitude. TNF-alpha increased the production of NO and total protein, but inhibited proteoglycan synthesis rates. TNF-alpha prevented the mechanical stimulation of proteoglycan synthesis, and this effect was not dependent on NOS2.

CONCLUSIONS

These findings indicate that pro-inflammatory cytokines can modulate the responses of meniscal cells to mechanical signals, suggesting that both biomechanical and inflammatory factors could contribute to the progression of joint disease as a consequence of altered loading of the meniscus.

Photosensitivity in lupus erythematosus

BACKGROUND

Lupus erythematosus is a systemic disease process that may manifest with a variety of internal and cutaneous findings. Photosensitivity is one the most common manifestations of lupus erythematosus. In patients with lupus erythematosus, there is a relationship between exposure to ultraviolet light, autoantibodies, genetics and other factors in the development of photosensitivity.

METHODS

Literature was reviewed on the topics of lupus erythematosus and photosensitivity discussed together and separately. The suggested mechanisms for their relationship were reviewed and analyzed.

RESULTS

Photosensitivity's relationship to and influence on the systemic manifestations of lupus remain to be defined. Mechanisms for photosensitivity might include: modulation of autoantibody location, cytotoxic effects, apoptosis induction with autoantigens in apoptotic blebs, upregulation of adhesion molecules and cytokines, induction of nitric oxide synthase expression and ultraviolet-generated antigenic DNA. Tumor necrosis factor alpha also seems to play a role in the development of photosensitivity.

CONCLUSION

The basis for photosensitivity in lupus has yet to be fully defined. It is more commonly associated with subacute and tumid lupus erythematosus than with other variants. Anti-Ro antibodies appear to relate to photosensitivity. Tumor necrosis factor alpha polymorphisms appear to be important in some variants of lupus with photosensitivity. There is no sine qua non antibody or mutation of photosensitivity in lupus. In patients with lupus, more work needs to be done to define the mechanisms of photosensitivity.

Decreased adrenomedullin and total nitrite levels in breast milk of preeclamptic women

OBJECTIVE

To observe the adrenomedullin (AM) and total nitrite levels in the milk of preeclamptic and normal pregnant women.

DESIGN AND METHODS

Fifteen women with preeclampsia and 15 normal pregnant women were included in the study. Total nitrite was quantitated by Griess reaction, while AM was measured by HPLC.

RESULTS

The levels of AM and total nitrite in colostrum and 30th-day breast milk were decreased in preeclamptics. Total nitrite levels (micromol/l) were 56.09 +/- 11.18 vs. 82.20 +/- 12.01, P < 0.05, in colostrum of preeclamptics and controls, respectively. The level of total nitrite was 37.75 +/- 12.10 vs. 53.28 +/- 10.25, P < 0.05, in 30th-day milk of same patients. AM levels (pg/ml) were 11.18 +/- 1.11 vs. 16.59 +/- 1.24, P < 0.0001, in colostrum of preeclamptics and controls, respectively. In 30th-day milk of same patients, AM levels were 8.41 +/- 1.39 vs. 12.18 +/- 1.48, P < 0.005, respectively.

CONCLUSION

This report shows for the first time that human milk has decreased levels of AM and total nitrite in preeclampsia.

Serum nitric oxide (NO) levels in systemic sclerosis patients: correlation between NO levels and clinical features

Vascular damage in systemic sclerosis (SSc) may be a factor in the abnormal regulation of several vasoactive agents. It has been well confirmed that plasma endothelin-1, as a vasoconstrictive factor, is elevated in patients with SSc. However, it is still controversial whether the levels of serum nitric oxide (NO), a strong vasodilator, are increased or decreased in SSc patients compared to healthy donors. In this study, we measured the levels of serum NO metabolites in SSc patients and determined the contribution of the excessive production of NO synthase (NOS)-2 by skin fibroblasts to NO synthesis. Serum NO levels of 45 patients with SSc were significantly higher than those of 20 healthy volunteers. In addition, some clinical features of SSc (the extent of skin fibrosis, short disease duration, and the complication of active fibrosing alveolitis) were all correlated positively with the levels of NO metabolites in SSc patients. To evaluate the levels of NOS-2 produced by skin fibroblasts, skin fibroblast cultures were established from SSc patients and healthy volunteers. Reverse transcription-polymerase chain reaction indicated that NOS-2 mRNA was spontaneously expressed in cultured fibroblasts derived from SSc patients, but not in those derived from healthy normal controls. Immunohistochemical staining also showed that NOS-2 proteins were detected in SSc fibroblasts but not in normal fibroblasts. The production of NO by cultured fibroblasts was visualized directly by a reagent (DAF-2 DA) used for the fluorescent detection of NO. Cultured SSc fibroblasts were capable of NO synthesis in culture media containing L-arginine, whereas normal fibroblasts (with no expression of NOS-2) did not synthesize detectable NO. These observations indicate that NO production is increased markedly in early-stage diffuse cutaneous SSc patients with active fibrosing alveolitis, and that constitutive NOS-2 expression in SSc fibroblasts may contribute to increased NO production.

Adrenomedullin and total nitrite levels in children with Henoch-Schönlein purpura

Nitric oxide (NO) is synthesized from endothelium and has an important role in the control of vascular tonus. Adrenomedullin (AM) is a potent vasodilator, and cytoprotective peptide is produced not only in adrenal medulla, but also in the vascular smooth muscle and endothelial cells. To investigate the endothelial synthesis of AM and NO, and endothelial injury in Henoch-Schönlein purpura (HSP), we measured their levels in 16 children with HSP, who were evaluated during the acute and remission phases, and compared with 12 healthy controls. Plasma AM levels (pmol/ml) were significantly higher in acute phase children (46.87+/-11.49) than in those in remission (35.59+/-12.39, p<0.01) and controls (30.70+/-9.12, p<0.001). Similarly, plasma total nitrite levels (mumol/l) were higher in acute phase patients (47.50+/-12.30) than in those in remission (35.94+/-10.08, p<0.005) and controls (34.56+/-11.51, p<0.05). Urinary excretion of AM (pmol/mg creatinine) was higher in acute phase patients (53.85+/-23.22) than in remission patients (29.97+/-9.33, p<0.01) and controls (37.43+/-15.78, p<0.05). Patients had increased urinary nitrite excretion (mumol/mg creatinine) in acute phase (2.39+/-1.18) compared to those in remission (1.53+/-0.90, p<0.05) and controls (1.05+/-0.61, p<0.005). There was no significant difference between remission phase and controls in AM and nitrite levels ( p>0.05). This study concluded that AM and NO may have a role in the immunoinflammatory process of HSP, especially in the active stage, although whether this perpetuates, or protects against, further vascular injury is not clear. Further studies are needed to clearly establish the roles of AM and NO in the pathogenesis of HSP.

Correlation of urinary nitric oxide concentrations with the development of hip dysplasia in Labrador retrievers

Urinary nitric oxide was determined in terms of the ratio of the concentrations of total urinary nitrite and nitrate:creatinine in 40 juvenile labrador retrievers, and radiographic signs of hip dysplasia and distraction indices were investigated in the same dogs in later life. The ratio was correlated significantly with the Norberg angle and with subchondral sclerosis in both hips, and with the grade of dysplasia in each hip and the dogs' overall grade of hip dysplasia. No correlations were observed between the ratio and the distraction indices or other radiographic criteria for hip dysplasia.

Age-related increases in LPS-stimulated nitric oxide production from cultured rat bone marrow cells

OBJECTIVE

To understand bone metabolism during senescence, we examined age-related change in nitric oxide (NO) production from bone marrow cells stimulated by lipopolysaccharide (LPS).

METHODS

We evaluated the age-related change in the NO production and expression of iNOS protein and mRNA of LPS-stimulated bone marrow cells collected from the tibiae of young and retired female and young and retired male rats. In addition, we used flow cytometry to assess changes in the distribution of CD14, a cell surface receptor of LPS.

RESULTS

The results revealed that NO production from bone marrow cells stimulated with LPS changed with aging. The NO levels in old rats were significantly higher (P<0.05) than those in young rats. Polymerase chain reaction (PCR) analysis indicated that the LPS-induced expression of iNOS mRNA was augmented in retired rats. Although the distribution pattern of the bone marrow cells was similar between young and retired rats, the percentage of CD14-positive cells in specific populations differed between the age groups. Specifically, in the granule-containing bone marrow cells, the percentage of CD14-positive cells was increased in retired rats.

CONCLUSION

Our results indicate that LPS-stimulated NO production from rat bone marrow cells increased with age and that the difference in responsiveness might be due to changes in the percentage of CD14-positive cells in the bone marrow.

Inducible nitric oxide synthase expression in chronic viral hepatitis and its relation with histological severity of disease

The role of nitric oxide in the pathogenesis of chronic viral hepatitis is not known. Elevated nitric oxide production is assumed to be responsible for the pathological changes in many inflammatory conditions, mainly via peroxynitrite, a potential oxidant that is produced by the reduction of superoxide anion with nitric oxide. The intensity and the distribution of the immunohistochemical staining of intrahepatic inducible nitric oxide synthase were studied in the biopsy specimens obtained from 63 patients with viral hepatitis and 13 patients with elevated transaminase levels of various aetiologies. Hepatic inducible nitric oxide synthase staining was significantly more intense in the viral hepatitis group (P = 0.000). Inducible nitric oxide synthase staining levels correlated well with the severity of the viral hepatitis using the Knodell's liver histological activity index (r = 0.393, P = 0.002) Among the viral hepatitis group, the pathological distribution of the inducible nitric oxide synthase staining favoured the periportal hepatocytes (zone 1) whereas less staining was observed in parenchymal hepatocytes zone of 2 and 3 and bile duct epithelium. As nitric oxide mediated nitration of hepatocellular proteins is elevated in inflamed hepatic tissues and is correlated with the severity of the disease, we suggest that inducible nitric oxide synthase can possibly have a critical role in the pathogenesis of chronic viral hepatitis.

Serum homocysteine level is increased and correlated with endothelin-1 and nitric oxide in Behçet's disease

BACKGROUND/AIMS

Behçet's disease (BD) is a systemic inflammatory vasculitis of young adults with unknown aetiology, characterised by endothelial dysfunction and occlusion in both deep venous and retinal circulation. Ocular involvement occurs in 70% of cases and is characterised by periphlebitis, periarteritis, vascular occlusion, and thrombosis leading to blindness despite vigorous treatment. Endothelin-1 (ET-1) is a vasoconstricting peptide while nitric oxide (NO) is a relaxing molecule and both are released by endothelium for blood flow regulation. Homocysteinaemia is a newly defined term connected to the increased risk of atherothrombotic and atherosclerotic systemic and retinal vascular occlusive diseases, and its role in the course of BD has not been previously described. The authors aimed to detect serum total homocysteine (tHcy), ET-1, and NO in BD and to assess if tHcy, ET-1, and NO are associated with ocular BD or disease activity.

METHODS

43 consecutive patients with ocular (n = 27) or non-ocular (n = 16) BD (36.95 (SD 9.80) years, 22 male, 21 female) satisfying international criteria, and 25 age and sex matched healthy control subjects (37.88 (8.73) years, 13 male, 12 female) without a history of systemic or retinal venous thrombosis were included in this study. Patients were examined by two ophthalmologists with an interest in BD. Serum tHcy, ET-1, and NO concentrations were measured in both groups. Hyperhomocysteinaemia was defined as a tHcy level above the 95th percentile in the control group. Patients were divided into active and inactive period by acute phase reactants including alpha(1) antitrypsin, alpha(2) macroglobulin, erythrocyte sedimentation rate, and neutrophil count.

RESULTS

The overall mean serum tHcy, ET-1, and NO levels were significantly higher in patients with BD than in control subjects (tHcy = 15.83 (4.44) v 7.96 (2.66) ng/ml, p <0.001; ET-1 = 17.47 (4.33) v 5.74 (2.34) micromol/ml, p <0.001; NO = 37.60 (10.31) v 27.08 (7.76) micromol/l, p <0.001). Serum tHcy, ET-1, and NO levels were significantly higher in active patients than in inactive patients and control subjects. In addition, among patients with ocular BD, the mean tHcy levels were significantly increased and correlated with ET-1 and NO levels when compared with non-ocular disease and control subjects. All acute phase reactant levels were significantly higher in active period than in inactive stage and controls.

CONCLUSIONS

Elevated tHcy may be responsible for the endothelial damage in BD and may be an additional risk factor for the development of retinal vascular occlusive disease, contributing to the poor visual outcome in these patients. Assessment of tHcy may be important in the investigation and management of patients with BD, especially with ocular disease.

Assessment of vascular function in systemic sclerosis: indications of the development of nitrate tolerance as a result of enhanced endothelial nitric oxide production

OBJECTIVE

To investigate the relationship between endothelium-dependent and endothelium-independent functions and the stiffness of conduit arteries as well as levels of endothelial activation markers in patients with systemic sclerosis (SSc).

METHODS

Endothelium-dependent (i.e., flow-mediated) and endothelium-independent (i.e., nitroglycerin-induced) dilation of the brachial artery was measured as the percentage of change from baseline (FMD% and NTG%, respectively) in 24 SSc patients and 24 age- and sex-matched healthy controls by high-resolution ultrasound imaging. The maximum increase in systolic pressure per unit of time (dP/dt(max)), as a measure of arterial wall stiffness, was assessed in the radial artery by pulse applanation tonometry. Plasma nitrate, the most important metabolite of nitric oxide, and 24-hour urinary excretion of nitrate were measured by gas chromatography mass spectrometry. Soluble E-selectin and soluble vascular cell adhesion molecule 1 (sVCAM-1) were measured by enzyme-linked immunosorbent assay.

RESULTS

Brachial artery FMD% and NTG% did not differ between SSc patients and controls. Radial artery dP/dt(max) was significantly increased in the patients and correlated significantly with elevated levels of plasma nitrate and sVCAM-1. Twenty-four-hour urinary nitrate excretion tended to be elevated. Brachial artery NTG% was significantly inversely correlated with levels of plasma nitrate and soluble endothelial adhesion molecules.

CONCLUSION

The ability of the brachial arteries to dilate in response to hyperemia and nitroglycerin challenge is preserved in SSc. Stiffness of the radial artery is increased, however. Endothelial activation seems to determine the extent of the brachial artery NTG% and the radial artery dP/dt(max). The data are compatible with the hypothesis that nitrate tolerance is present in the vascular smooth muscle cells of the brachial artery wall in SSc.

Comparison of nitric oxide donors in lowering intraocular pressure in rabbits: role of cyclic GMP

L-arginine-nitric oxide (NO) pathway participates in the physiology and in many pathological processes in the eye, such as glaucoma. The aim of the present study was to compare the ocular hypotensive effect of different NO-donors, and to get more information on the role of cyclic guanosine 3',5'-monophosphate (cGMP) in this process. The test compounds were administered topically or intravitreally in the eye of a normotensive rabbit. Intraocular pressure (IOP) was measured with a pneumatonometer after topical anesthesia. The metabolites of NO (nitrite, nitrate, NOx) and cGMP were assayed from the aqueous humor and plasma. NO-synthase (NOS) protein expression was assayed in the ciliary body by Western blotting. The maximal lowering of IOP was achieved as follows: atriopeptin III (concentration 78 (microM, decrease in IOP 50%), atriopeptin II (84 (microM 37%). 8-Br-cGMP (90 mM, 37%), zaprinast + 8-Br-cGMP (1 mM + 90 mM, 34%), L-arginine (1 mM, 29%), SNP (40 mM, 28%), nitrosocaptopril (100 mM, 28%), S-nitrosothiol (SNOG) (10 mM, 27%), YC-1 (10 (microM, 25%), zaprinast + SNP (1 mM + 40 mM, 22%), spermine NONOate (100 mM, 20%) [corrected]. The decrease in IOP lasted for 2-5 hr, except with atriopeptin II and III, when IOP values were first normalized in 6 hr and 2 days, respectively. In conclusion, the results of the present study indicate that by increasing the activity of L-arginine/NO/cGMP-pathway it is possible to lower IOP in rabbits equally to the currently used antiglaucomatous drugs.

Óxido nítrico: revisão

O óxido nítrico é um mediador gasoso responsável por uma variedade de fenômenos fisiológicos. A l-arginina é a precursora da síntese do óxido nítrico, na presença de óxido nítrico-sintase. Este artigo revê as funções das óxido nítrico-sintases e como o óxido nítrico atua na permeabilidade vascular e na síndrome de isquemia e reperfusão, assim como possíveis métodos para sua mensuração.