Urinary Nitrate Research Articles

Selective Cyclooxygenase-2 Inhibitor Suppresses Renal Thromboxane Production but Not Proliferative Lesions in the MRL/lpr Murine Model of Lupus Nephritis

IntroductionProliferative lupus nephritis (LN) is marked by increased renal thromboxane (TX) A2 production. Targeting the TXA2 receptor or TXA2 synthase effectively improves renal function in humans with LN and improves glomerular pathology in murine LN. This study was designed to address the following hypotheses: (1) TXA2 production in the MRL/MpJ-Tnfrsf6lpr/J (MRL/lpr) model of proliferative LN is cyclooxygenase (COX)-2 dependent and (2) COX2 inhibitor therapy improves glomerular filtration rate (GFR), proteinuria, markers of innate immune response and glomerular pathology. MethodsTwenty female MRL/lpr and 20 BALB/cJ mice were divided into 2 equal treatment groups: (1) SC-236, a moderately selective COX2 inhibitor or (2) vehicle. After treatment from the age of 10 to 20 weeks, the effectiveness of inhibition of TXA2 was determined by measuring urine TXB2. Response endpoints measured at the age of 20 weeks were renal function (GFR), proteinuria, urine nitrate + nitrite (NOx) and glomerular histopathology. ResultsSC-236 therapy reduced surrogate markers of renal TXA2 production during early, active glomerulonephritis. When this pharmacodynamic endpoint was reached, therapy improved GFR. Parallel reductions in markers of the innate immune response (urine NOx) during therapy were observed. However, the beneficial effect of SC-236 therapy on GFR was only transient, and renal histopathology was not improved in late disease. ConclusionsThese data demonstrate that renal TXA2 production is COX2 dependent in murine LN and suggest that NO production is directly or indirectly COX2 dependent. However, COX2 inhibitor therapy in this model failed to improve renal pathology, making COX2 inhibition a less attractive approach for treating LN.

Nitric oxide production is increased in severely obese children and related to markers of oxidative stress and inflammation

ObjectiveNitric oxide (NO) is the major endothelium-derived relaxing factor. The aim of the present study was to evaluate NO synthesis and metabolism in severely obese children with different degrees of metabolic risk and to ascertain their relation with the parameters of oxidative stress and inflammation. MethodsThe study involved 60 obese children evaluated with respect to metabolic risk factors (MRFs) (32<4 MRFs and 28≥4 MRFs) and 50 normal weight children between 7 and 14 years of age. Nutritional status was assessed by clinical and anthropometric examination. MRFs (serum lipid profile, insulin resistance indexes, blood pressure) in addition to uric acid, homocysteine, leptin, and inflammatory markers were measured. Plasma nitrite, nitrate and nitrotyrosine concentrations, and urinary nitrate were determined as markers of NO production and nitrosative stress. Malondialdehyde, 8-isoprostane F2α, and advanced oxidation protein products were analyzed in plasma to assess oxidative stress. ResultsCompared with healthy controls, the obese children had significantly increased concentrations of markers of NO synthesis and nitrosative and oxidative stress that were correlated with each another. Increased NO production in obese children was associated with MRFs; plasma nitrate to waist circumference (r=0.388, p=0.003), uric acid (r=0.404, p<0.001), and tumor necrosis factor α (r=0.302, p=0.021), and plasma nitrite to triglycerides (r=0.432, p<0.001). ConclusionNO synthesis and nitrosative stress are increased in severely obese children and correlated with anthropometric parameters indicative of abdominal obesity, oxidative stress and inflammatory markers.

Serum and Urinary Nitrites and Nitrates and Doppler Sonography in Detection of Early Diabetic Complications

Objective: to evaluate serum and urinary nitrite and nitrate concentrations as an index of nitric oxide (NO) production in type1diabetes mellitus (T1DM) and to investigate the possible alteration and correlation with intra renal Doppler resistive indexes (RIs). Design: The study included 90 children and adolescent with T1DM divided into 2 groups: Group 1: included 45 prepubertal type1 diabetics who were defined as Tanner stage1. Their age ranged between 8-14 years. Group 2: included 45 pubertal type diabetics who were defined as Tanner stages 2-5. Their ages ranged between 15-19 years. They were compared to 45 age and sex matched healthy controls. Clinical examination was done. Laboratory investigations included; post-prandial blood glucose (PPBG), glycosylated heamoglobin (HbA1C), Fundus examination, urinary microalbumin and measurement of serum and urinary nitrite and nitrate levels. Doppler ultrasonographic registration of intrarenal RIs were performed. Results: Compared to controls, both diabetic groups had significantly increased concentrations of serum (P=0.001) and urinary NO (P=0.008).Doppler RIs values were significantly elevated in both diabetic groups compared to controls (P<0.001).A significant positive correlation was found between serum and urinary NO levels (P<0.001). Serum NO was positively correlated with Doppler RIs (P=0.002), HbA1c (P=0.012), PPBG (P=0.000) and diabetes duration (P=0.004). Doppler RIs were positively correlated with mean HbA1c (P=0.025), PPBG (P=0.001) and diabetes duration (P=0.000). Conclusion: In type 1 diabetes chronic hyperglycemia may act through a mechanism that involves increased NO production or action and contributes to generating intrarenal hemodynamic abnormalities which could be detectable by Doppler ultrasonography even before overt clinical nephropathy. Further follow up studies are needed to document the usefulness of Doppler ultrasound in detection of preclinical nephropathy.

OP054 REGULATION OF NEURONAL SURVIVAL FACTORS BY ß-HYDROXY-ß-METHYLBUTYRATE (HMB): FUTURE THERAPEUTIC IMPLICATIONS

plasma [13C]-ketoisocaproate and leucine oxidation from breath CO2. Results: Compared with placebo, oral citrulline supplementation increased plasma citrulline (mean±SD, 303±98 vs. 27±5mmol/L, P< 0.001), arginine (163±25 vs.72±154mmol/L, P< 0.001) and ornithine (96±37 vs. 52±14mmol/L, P< 0.001) concentrations, but failed to affect albumin, transthyretin, insulin and insulin-like growth factor (IGF)-1 plasma concentrations, urinary nitrate excretion, or nitrogen balance ( 4.8±2.4 vs. 4.1±2.5 g/6 h). Protein breakdown (125±8 vs. 124±9 mmol/kg/h), leucine oxidation (23±3 vs. 22±4mmol/ kg/h), and whole-body protein synthesis (102±9 vs. 102±6mmol/kg/h) were not affected by citrulline supplementation. Conclusion: In healthy volunteers, oral citrulline does not affect whole-body protein kinetics in the postabsorptive state, but strongly increases plasma citrulline and arginine availabilities.

OP053 TRANSCRIPTION OF THE MEVALONATE PATHWAY IS UP-REGULATED BY AMINO ACIDS IN L6 SKELETAL MUSCLE CELLS SUGGESTING LOCAL STEROIDOGENESIS FOR ANABOLIC REACTIONS

plasma [13C]-ketoisocaproate and leucine oxidation from breath CO2. Results: Compared with placebo, oral citrulline supplementation increased plasma citrulline (mean±SD, 303±98 vs. 27±5mmol/L, P< 0.001), arginine (163±25 vs.72±154mmol/L, P< 0.001) and ornithine (96±37 vs. 52±14mmol/L, P< 0.001) concentrations, but failed to affect albumin, transthyretin, insulin and insulin-like growth factor (IGF)-1 plasma concentrations, urinary nitrate excretion, or nitrogen balance ( 4.8±2.4 vs. 4.1±2.5 g/6 h). Protein breakdown (125±8 vs. 124±9 mmol/kg/h), leucine oxidation (23±3 vs. 22±4mmol/ kg/h), and whole-body protein synthesis (102±9 vs. 102±6mmol/kg/h) were not affected by citrulline supplementation. Conclusion: In healthy volunteers, oral citrulline does not affect whole-body protein kinetics in the postabsorptive state, but strongly increases plasma citrulline and arginine availabilities.

Plasma dimethylarginines during the acute inflammatory response

Asymmetric dimethylarginine (ADMA) concentrations are increased in critically ill patients and may play a role in multiple organ failure. However, plasma ADMA concentrations during the development of the inflammatory response have not been documented. We measured plasma ADMA, as well as urinary excretion of its major metabolite dimethylamine, and nitrate as a marker of nitric oxide synthase (NOS) activity, in a cohort of patients undergoing elective knee arthroplasty that is known to provoke a significant inflammatory response. Thirty-eight patients were recruited. Fasting venous blood samples were obtained pre-operatively and at 12h and daily until the fifth post-operative day. ADMA and symmetric dimethylarginine (SDMA) were measured by high-performance liquid chromatography (HPLC). Urinary dimethylamine and nitrate were measured pre-operatively and on each of the post-operative mornings using HPLC and expressed as a ratio to creatinine. Plasma ADMA fell by a median of 31% during the post-operative period, reaching a nadir on day 2, and recovering to baseline by the end of the study. SDMA showed no significant changes. No increase in urinary dimethylamine excretion was noted until day 5 post-op, whereupon it doubled. Urinary nitrate showed a small, but nonsignificant decrease on day 2, suggesting no major activation of NOS activity. Plasma ADMA concentration decreases rapidly and transiently during the first 48h of acute inflammation. This appears not be caused by increased catabolism and may reflect increased cellular partitioning. This may serve to regulate NOS activity and prevent harmful increases in inducible NOS in situations where it is not appropriate.

Nitric oxide generation in children with malaria and the NOS2G-954C promoter polymorphism

Previous epidemiological studies have demonstrated a protective association between the NOS2G-954C (NOS2(Lambaréné)) polymorphism in inducible nitric oxide synthase and severe malaria. The polymorphism is commoner in children with uncomplicated compared with severe malaria. We now show that the likely mechanism for such protection is increased flux of nitrogen from arginine to nitric oxide (NO) during episodes of malaria. Forty-seven boys with uncomplicated malaria received an infusion of (15)N-arginine to measure directly whole body in vivo NO production. The NOS2G-954C genotype previously associated with reduced risk of severe malaria in Gabon was also assessed. Evaluable data were obtained from 40 boys, of whom 6 were NOS2G-954C heterozygotes. Heterozygotes had higher urinary (15)N nitrate enrichments, 2.3 ± 0.6 vs. 1.4 ± 0.5 atoms percent excess (P = 0.001) and higher ratios of (15)N between urine nitrate and plasma arginine (87 ± 11 vs. 57 ± 18%, P = 0.001) consistent with accelerated NO production. We also derived total NO production rates, combining data with total urine production rate and nitrate concentration; these showed no difference by genotype (0.62 ± 0.36, n = 6 vs. 0.83 ± 0.50 μmol/kg·h, n = 16; P = 0.36), but data were confounded by very high variability in measurements of urine output and nitrate concentrations. This study supports the idea that NOS2 genotype protects against severe malaria by increasing NO production during episodes of uncomplicated malaria.

Dietary fish oil impairs induction of γ‐interferon and delayed‐type hypersensitivity during a systemic Salmonella enteritidis infection in rats

Fish oil that is rich in n-3 polyunsaturated fatty acids markedly modulates immunological responses. Literature data indicate that the fish oil reduces cellular immunity and therefore impairs resistance to infections. We have investigated how dietary fish oil affects the immune response against a facultative intracellular pathogen, Salmonella enteritidis. Wistar rats were fed a diet containing 16% (w/w) of either fish oil or corn oil. After a 4-week adaptation period, rats were intraperitoneally challenged with 4 x 10(5) cfu of S. enteritidis. During the 14-day infection period, urine was collected on a daily basis. At days 2 and 14, eight rats per group were sacrificed. Urinary nitrate, used as a marker for NO production, was lower on a fish oil diet during days 3-8. At day 2, serum gamma-interferon was 48 +/- 7 pg/mL in the fish oil-fed rats compared with 162 +/- 52 pg/mL in the corn oil-fed rats. No effects were found on living salmonella in liver and spleen. At day 14, as markers of an impaired T-helper 1 (Th-1) response, a 38% lower delayed-type hypersensitivity responses and a lower salmonella-specific IgG2b were observed in the fish oil-fed rats. Although here dietary fish oil has affected only immune parameters, this impairment of the innate and Th-1-mediated immune response may have implications for the host resistance against other intracellular pathogens.

Impact of the estrus cycle and reduction in estrogen levels with aromatase inhibition, on renal function and nitric oxide activity in female rats

Estradiol increases mRNA and/or protein expression of the nitric oxide synthase (NOS) isoforms in a variety of tissues including kidney. In this study we determined the relationship between cyclical variations in estradiol levels and renal function and total NO production in the virgin female rat. In addition, we used an aromatase inhibitor (Anastrozole), to inhibit synthesis of estradiol from testosterone. Estradiol levels were higher in proestrus vs. diestrus, and were markedly suppressed by 7 days treatment with aromatase inhibitor. There was no difference in total NO production (from urinary and plasma nitrate + nitrite = NO X) between proestrus and diestrus but aromatase inhibition resulted in increases in total NO production. The renal cortical NOS activity and protein abundance also increased in aromatase-inhibited female rats. There were no differences in blood pressure (BP) in any group but the renal vascular resistance (RVR) was low in proestrus, increased in diestrus and did not change further after aromatase inhibition. In summary, the cyclical changes in renal function correlate with estradiol but not NO levels. Pharmacologic castration with aromatase inhibition leads to a marked increase in total and renal NOS. This contrasts to earlier work where surgical castration causes decreased NOS.

Involvement of salivary glands in regulating the human nitrate and nitrite levels

Objective To study the dynamic fluctuations of nitrate and nitrite content in humans following damage to major salivary glands. Methods Fifteen nasopharyngeal carcinoma patients, scheduled to undergo IMRT, were recruited. The prescription dose to GTV, CTV1 and CTV2, was 68, 60 and 54 Gy, respectively, in 30 fractions, 1 fraction/day. Saliva, serum and urine samples were collected at baseline, RT10, RT20 and at endpoint of radiation. Ions concentration was determined using ion chromatography. Results Salivary flow rates and nitrate content decreased over time ( p < 0.0001), whereas serum and urinary nitrite rose. Salivary nitrite increased transiently and then plateaued. Cumulative irradiation dose to salivary glands correlated with nitrate content in serum ( p < 0.0001), but not in saliva and urine ( p = 0.876 and p = 0.175). The salivary flow rates correlated to the nitrate content in serum ( p < 0.0001), but not in saliva and urine ( p = 0.230 and p = 0.428). Conclusions Nitrate and nitrite contents in saliva, serum or urine changed in response to salivary gland damage. Salivary glands are associated with the metabolism of both ions in humans. The decreased serum nitrate appears to provide adjuvant information about salivary dysfunction.

Human pharmacology of hydrogen sulfide, putative gaseous mediator

Nitric oxide (NO), the first low molecular weight inorganic gas to be established as a biological mediator, had previously been regarded merely as a toxic pollutant. It was joined, similarly implausibly to the minds of a generation brought up with the hazards of coal gas as domestic heating, by carbon monoxide (CO) – potentially lethal as an exhaust gas, but also formed in mammalian tissues together with biliverdin by inducible and/ or constitutive forms of haem oxygenase, and implicated subsequently as a signalling molecule, not only in the central nervous system (especially olfactory pathways) and cardiovascular system but also in respiratory, gastrointestinal, endocrine and reproductive functions [1]. Hydrogen sulfide (H2S) was known to generations of schoolboys in one biological context – as the source of the odour of rotten eggs – but even so, the proposal in the early 2000s [2] that it too is a gaseous mediator was met with some scepticism.The toxicology of H2S had previously been studied [3], and actions on enzymes including monoamine oxidase and carbonic anhydrase identified, but more recent work has also shown a rich and diverse pharmacology consistent with functions as a signalling molecule under physiological conditions. It has also been implicated both as a harmful and also as a protective factor in the pathophysiology of a range of experimental models of disease [4], and its therapeutic potential has attracted comment [5]. There are striking similarities between these three gaseous mediators, as well as contrasts, that underlie complex and imperfectly understood functional interactions between them. All three are highly diffusible labile molecules that are rapidly eliminated from the body: NO as nitrite and nitrate in urine as well as NO in exhaled air; CO in exhaled air; H2S as thiosulfate, sulfite and sulfate in urine (Figure 1) as well as (it emerges, see below) in exhaled breath. All three react with haemoglobin, yielding methaemoglobin or nitrosylhaemoglobin (respectively inactive and active metabolites) from distinct reactions of haem and of globin with NO; carboxyhaemoglobin or sulfhaemoglobin from CO or H2S. All three affect cellular energetics via actions on cytochrome c oxidase. All three have vasodilator effects, and all have anti-inflammatory and cytoprotective effects at low concentrations in contrast to causing cellular injury at higher concentrations – consistent with Paracelsus’s aphorism that the distinction between drugs and poisons is determined exclusively by the dose.

Goitrogenic Anions, Thyroid-Stimulating Hormone, and Thyroid Hormone in Infants

BackgroundEnvironmental exposure of infants to perchlorate, thiocyanate, nitrate, might interfere with thyroid function. U.S. women with higher background perchlorate exposure have higher thyroid-stimulating hormone (TSH) and lower thyroxine (T4). There are no studies with individual measures of thyroid function and these goitrogens available in infants.ObjectiveWe examined the association of urinary perchlorate, nitrate, iodide, and thiocyanate with urinary T4 and TSH in infants and whether that association differed by sex or iodide status.MethodsWe used data and samples from the Study of Estrogen Activity and Development, which assessed hormone levels of full-term infants over the first 12 months of life. The study included 92 full-term infants between birth and 1 year of age seen up to four times. Perchlorate, thiocyanate, nitrate, and iodide were measured in 206 urine samples; TSH and T4 and were measured in urines and in 50 blood samples.ResultsIn separate mixed models, adjusting for creatinine, age, sex, and body mass index, infants with higher urinary perchlorate, nitrate or thiocyanate had higher urinary TSH. With all three modeled, children with higher nitrate and thiocyanate had higher TSH, but higher perchlorate was associated with TSH only in children with low iodide. Unexpectedly, exposure to the three chemicals was generally associated with higher T4.ConclusionsThe association of perchlorate exposure with increased urinary TSH in infants with low urinary iodide is consistent with previous findings. Higher thiocyanate and nitrate exposure were also associated with higher TSH in infants.

No arguments for increased endothelial nitric oxide synthase activity in migraine based on peripheral biomarkers

To assess whether migraine patients display a chronic nitric oxide synthase (NOS) hyperactivity by comparing the nitric oxide (NO) production before and following a loading dose of L-arginine between migraine patients (interictally) and matched healthy control subjects. In addition, we evaluated whether a loading dose of L-arginine triggers an acute migraine headache in migraineurs. Twenty healthy subjects and 20 migraine patients participated in a 2-period, randomised, double-blind, placebo-controlled study. Each subject received a 30-min infusion, by peripheral vein, of 30 g L-arginine hydrochloride or placebo (i.e. an equal volume of 0.9% saline solution). Meanwhile, biomarkers associated with the L-arginine-NO pathway (i.e. exhaled NO/nasal NO), plasma citrulline and urinary excretion of nitrite/nitrate and cGMP were assessed before and for 6 h following the start of the infusion. At baseline, exhaled NO and nasal NO were higher in migraineurs compared to healthy subjects (mean±95% confidence interval): 15.9 (8.8, 23.0) parts per billion (ppb) versus 10.8 (7.0, 14.5) ppb for exhaled NO (P=0.04) and 76.3 (61.2, 91.4) versus 61.6 (51.2, 72.0) ppb for nasal NO (P=0.03), respectively. The AUC0-6 in ppb for exhaled NO and nasal NO following L-arginine or saline infusion did not differ between both groups. The increase in L-citrulline, following L-arginine infusion, was smaller in migraine patients (15 (13, 18) µmol/l) compared to healthy volunteers (19 (16, 23) µmol/l; P=0.046). In healthy subjects, both nitrate and cGMP excretion were higher following L-arginine compared to placebo infusion: 132.63 (100.24, 165.02) versus 92.07 (66.33, 117.82) µmol/mmol creatinine for nitrate (P=0.014) and 50.53 (42.19, 58.87) versus 39.64 (33.94, 45.34) nmol/mmol creatinine for cGMP (P=0.0003), respectively. In migraineurs, excretion of these biomarkers was comparable following L-arginine or saline infusion. The results of the present study do not support the idea of a generalised increase in NO synthase activity in migraine patients outside of a migraine attack. The smaller increase in plasma L-citrulline, urinary nitrate and cGMP excretion following L-arginine infusion in migraine patients might indicate dysfunction of endothelial NO synthase.

Specific Dietary Polyphenols Attenuate Atherosclerosis in Apolipoprotein E–Knockout Mice by Alleviating Inflammation and Endothelial Dysfunction

Animal and clinical studies have suggested that polyphenols in fruits, red wine, and tea may delay the development of atherosclerosis through their antioxidant and anti-inflammatory properties. We investigated whether individual dietary polyphenols representing different polyphenolic classes, namely quercetin (flavonol), (-)-epicatechin (flavan-3-ol), theaflavin (dimeric catechin), sesamin (lignan), or chlorogenic acid (phenolic acid), reduce atherosclerotic lesion formation in the apolipoprotein E (ApoE)(-/-) gene-knockout mouse. Quercetin and theaflavin (64-mg/kg body mass daily) significantly attenuated atherosclerotic lesion size in the aortic sinus and thoracic aorta (P<0.05 versus ApoE(-/-) control mice). Quercetin significantly reduced aortic F(2)-isoprostane, vascular superoxide, vascular leukotriene B(4), and plasma-sP-selectin concentrations; and augmented vascular endothelial NO synthase activity, heme oxygenase-1 protein, and urinary nitrate excretion (P<0.05 versus control ApoE(-/-) mice). Theaflavin showed similar, although less extensive, significant effects. Although (-)-epicatechin significantly reduced F(2)-isoprostane, superoxide, and endothelin-1 production (P<0.05 versus control ApoE(-/-) mice), it had no significant effect on lesion size. Sesamin and chlorogenic acid treatments exerted no significant effects. Quercetin, but not (-)-epicatechin, significantly increased the expression of heme oxygenase-1 protein in lesions versus ApoE(-/-) controls. Specific dietary polyphenols, in particular quercetin and theaflavin, may attenuate atherosclerosis in ApoE(-/-) gene-knockout mice by alleviating inflammation, improving NO bioavailability, and inducing heme oxygenase-1. These data suggest that the cardiovascular protection associated with diets rich in fruits, vegetables, and some beverages may in part be the result of flavonoids, such as quercetin.

Quantification of 15N-Nitrate in Urine with Gas Chromatography Combustion Isotope Ratio Mass Spectrometry to Estimate Endogenous NO Production

The use of stable isotope labeled substrates and subsequent analysis of urinary nitrate, forms a noninvasive test for evaluation of the in vivo NO metabolism. The present paper describes a new method for simultaneous quantification of (15)N-nitrate and total nitrate with gas chromatography combustion isotope ratio mass spectrometry (GC-C-IRMS). Nitrate, isolated from urine with a nitrate selective resin, was reduced to nitrite using copperized cadmium. Subsequently, Sudan I was formed by diazotation. Sudan II was added as internal standard, and both molecules were analyzed with GC-C-IRMS as tert-butyldimethylsilyl derivatives. The accuracy was determined during a recovery study of two different known nitrate concentrations and two (15)N-enrichments. A recovery of 101.6% and 103.9% for total nitrate and 107.6% and 91.2% for (15)N-nitrate was obtained, respectively. The validated method was applied on complete 72 h urine collections after intravenous administration of (15)N-nitrate and (15)N-arginine in humans. On average, 51.8% (47.0-71.0%) of administered (15)N-nitrate was excreted, while 0.68% (0.44-1.17%) of (15)N-arginine was metabolized to nitrate. In conclusion, this method can be used for accurate simultaneous determination of (15)N-nitrate and total nitrate concentrations in urine and can be applied in clinical studies for noninvasive evaluation of NO metabolism in vivo.

Sinigrin suppresses nitric oxide production in rats administered intraperitoneally with lipopolysaccharide

Sinigrin, a glucosinolate contained in cruciferous vegetables, is converted to allyl isothiocyanate by plant myrosinase or microbial myrosinase in gut microflora. The intake of sinigrin significantly decreases the urinary nitrate + nitrite level (a nitric oxide [NO] production marker) in rats administered intraperitoneally with lipopolysaccharide (LPS). This result demonstrates that sinigrin suppresses NO production and therefore likely has an antioxidative effect in vivo.

Urinary biomarker of oxidative stress in patients with psoriasis vulgaris and atopic dermatitis

The involvement of oxidative stress in the pathogenesis of various skin disorders has been suggested for decades. However, few clinical studies have assessed oxidative stress in skin diseases. The easiest and least invasive method to assess oxidative stress in patients may be the measurement of oxidation products in urine. This study aims to assess oxidative stress in psoriasis and atopic dermatitis patients. Urine samples were collected from 29 psoriasis patients (25 males and 4 females), 21 atopic dermatitis patients (14 males and 7 females) and 20 healthy controls (16 males and 4 females). The severity and extent of psoriasis and atopic dermatitis was assessed by their area and severity index. We measured nitrate as a metabolite of nitric oxide, malondialdehyde as a major lipid oxidation product, and 8-hydroxydeoxyguanosine (8-OHdG) as a DNA oxidation marker. Urinary nitrate and 8-OHdG levels, but not malondialdehyde, were significantly higher in psoriasis patients than those in healthy controls. On the contrary, only urinary nitrate level was significantly higher in atopic dermatitis patients than those in healthy controls. The severity and extent of both psoriasis and atopic dermatitis significantly correlated with urinary nitrate level and malondialdehyde level, but it did not correlate with urinary 8-OHdG level. Measurement of these three urinary oxidative products is non-invasive. Above all, measurement of urinary nitrate may be most useful in the clinical assessment of oxidative stress in both psoriasis and atopic dermatitis patients. There is a possibility that urinary 8-OHdG level may indicate the different pathogenesis between psoriasis and atopic dermatitis.

Pollutant Chemicals, Thyrotropin, and Thyroid Hormone in Infants

ISEE-0440 Background and Objective: Infants are exposed to chemicals that might interfere with thyroid function, such as perchlorate, thiocyanate, and nitrate. There are no studies available with individual measures of these chemicals and thyroid function in infants. We examined whether urinary perchlorate, nitrate, or thiocyanate is associated with urinary thyroxine (T4) and thyroid stimulating hormone (TSH) in infants. Because background perchlorate exposure has been associated with changes in thyroid hormone levels in adults, we specifically examined whether perchlorate was associated with higher TSH in infants with low iodide and in infant girls, as was seen in US females over age 12 years. Methods: The study was conducted at the Children’s Hospital of Philadelphia, the Hospital of the University of Pennsylvania, and affiliated clinics, among 92 full term infants (47 males and 45 females) between birth and 1 year of age. We used data from the Study of Estrogen Activity and Development, which was a partly cross-sectional, partly longitudinal study designed to assess hormone levels of full term infants over the first 12 months of life. We analyzed urine samples collected in that study. Main Outcome Measures: Urinary perchlorate, thiocyanate, nitrate, iodide, TSH and T4, and blood TSH and T4. Results: In models with single chemical agents, infants with higher perchlorate had higher TSH and T4. In models with all three chemical agents, infants with low iodide and higher perchlorate had higher T4 and TSH; infants with higher urinary thiocyanate or higher urinary nitrate had higher urinary TSH and T4. Conclusions: The association of perchlorate exposure with increased urinary TSH in infants with low urinary iodide is consistent with previous findings in females aged 12 and older. Higher thiocyanate and nitrate exposure is also associated with higher urinary TSH in infants. (Supported in part by the intramural research program of NIH.)

Th1 and Th17 Cells Induce Proliferative Glomerulonephritis

Th1 effector CD4+ cells contribute to the pathogenesis of proliferative and crescentic glomerulonephritis, but whether effector Th17 cells also contribute is unknown. We compared the involvement of Th1 and Th17 cells in a mouse model of antigen-specific glomerulonephritis in which effector CD4+ cells are the only components of adaptive immunity that induce injury. We planted the antigen ovalbumin on the glomerular basement membrane of Rag1(-/-) mice using an ovalbumin-conjugated non-nephritogenic IgG1 monoclonal antibody against alpha3(IV) collagen. Subsequent injection of either Th1- or Th17-polarized ovalbumin-specific CD4+ effector cells induced proliferative glomerulonephritis. Mice injected with Th1 cells developed progressive albuminuria over 21 d, histologic injury including 5.5 +/- 0.9% crescent formation/segmental necrosis, elevated urinary nitrate, and increased renal NOS2, CCL2, and CCL5 mRNA. Mice injected with Th17 cells developed albuminuria by 3 d; compared with Th1-injected mice, their glomeruli contained more neutrophils and greater expression of renal CXCL1 mRNA. In conclusion, Th1 and Th17 effector cells can induce glomerular injury. Understanding how these two subsets mediate proliferative forms of glomerulonephritis may lead to targeted therapies.

Evidence by gas chromatography–mass spectrometry of ex vivo nitrite and nitrate formation from air nitrogen oxides in human plasma, serum, and urine samples

Nitrite and nitrate in body fluids and tissues result from dietary source, endogenous nitric oxide (NO) production and from NO and its higher oxides (NO x) present as pollutants in the atmosphere. Nitrite and nitrate in human blood serum and plasma or urine are commonly used as biomarkers and measures of endogenous NO synthesis. In addition to dietary intake of nitrite and nitrate, our study indicates that NO x naturally present in the laboratory air may be an abundant source for nitrite and nitrate in human serum, plasma, and urine ex vivo. These artifacts can be effectively reduced by closing sample-containing vials during sample treatment.