Anti-gout activity and the interaction mechanisms between Sanghuangporus vaninii active components and xanthine oxidase.

Xanthine oxidase (XO) plays a critical role in the progression of gout. We showed in a previous study that Sanghuangporus vaninii (S. vaninii), a perennial, medicinal, and edible fungus traditionally used to treat various symptoms, contains XO inhibitors. In the current study, we isolated an active component of S. vaninii using high performance countercurrent chromatography and identified it as davallialactone using mass spectrometry with 97.726 % purity. A microplate reader showed that davallialactone had mixed inhibition of XO activity with a half-inhibitory concentration value of 90.07 ± 2.12 µM. In addition, the collision between davallialactone and XO led to fluorescence quenching and conformational changes in XO, which were mainly driven by hydrophobicity and hydrogen bonding. Molecular simulations further showed that davallialactone was located at the center of the molybdopterin (Mo-Pt) of XO and interacted with amino acid residues Phe798, Arg912, Met1038, Ala1078, Ala1079, Gln1194, and Gly1260, suggesting that entering the enzyme-catalyzed reaction was unfavorable for the substrate. We also observed face-to-face π-π interactions between the aryl ring of davallialactone and Phe914. Cell biology experiments indicated that davallialactone reduced the expression of the inflammatory factors, tumor necrosis factor alpha and interleukin-1 beta (P < 0.05), can effectively alleviate cellular oxidative stress. This study showed that davallialactone significantly inhibits XO and has the potential to be developed into a novel medicine to prevent hyperuricemia and treat gout.

Lactic acid bacteria strains relieve hyperuricaemia by suppressing xanthine oxidase activity via a short-chain fatty acid-dependent mechanism.

Globally, the incidence of hyperuricaemia is steadily increasing. The evidence increasingly suggests an association between hyperuricaemia and the gut microbiota, which may enable the development of a novel therapeutic approach. We studied the effects of treatment with lactic acid bacteria (LAB) on hyperuricaemia and their potential underlying mechanisms. A mouse model of hyperuricaemia was generated by oral gavage with hypoxanthine and intraperitoneal injections of potassium oxonate for 2 weeks. The anti-hyperuricaemic activities of 10 LAB strains relative to allopurinol as a positive drug control were investigated in the mouse model. Lactobacillus rhamnosus R31, L. rhamnosus R28-1 and L. reuteri L20M3 effectively reduced the uric acid (UA) concentrations in serum and urine and the xanthine oxidase (XOD) activity levels in serum and hepatic tissue in mice with hyperuricaemia. These strains also reversed the elevated lipopolysaccharide (LPS) concentration, hepatic inflammation and slight renal injury associated with hyperuricaemia. A correlation analysis revealed that UA-reducing LAB strains promoted short-chain fatty acid (SCFA) production to suppress serum and hepatic XOD activity by increasing the abundances of SCFA production-related gut bacterial taxa. However, the UA-reducing effects of LAB strains might not be mediated by purine degradation. In summary, L. rhamnosus R31, L. rhamnosus R28-1 and L. reuteri L20M3 relieved hyperuricaemia in our mouse model by promoting SCFA production in a purine degradation-independent manner. Our findings suggest a novel therapeutic approach involving LAB strains for hyperuricaemia.

Chaetomium globosum extract mediated gold nanoparticle synthesis and potent anti-inflammatory activity.

Gold nanoparticles (AuNPs) are gaining a lot of attention in recent decades from researchers due to their unique optoelectronic properties and their significance in the field of biomedicine. Keeping this in view, our research work was designed to investigate gold nanoparticles obtained by using a fungal endophytic strain Chaetomium globosum, isolated from Vitex negundo which showed significant activity on enzyme inhibition. In the present study, the fungal isolate C. globosum was characterized using HPLC and LC-MS. A novel compound Catechin was matched with standard Catechin. Further, the endophyte C. globosum extract was utilized to synthesize gold nanoparticles (CgAuNPs) which was analysed by UV-visible spectroscopy. The CgAuNPs exhibited wine red color and the absorption peak appeared at 542 nm confirming the formation of the AuNPs. Further, Fourier Transmission Infrared Spectroscopy (FTIR) was performed to confirm the various functional groups present in mycosynthesized CgAuNPs. FTIR analysis demonstrated the presence of amines, flavonoids, as well as the presence of amide I linkage which possibly reduces Au+ to Au0. The synthesized CgAuNPs exhibited potential cytotoxicity against HeLa cells in a dose dependent manner. Further, CgAuNPs demonstrated significant anti-inflammatory activity. Overall, the present work provides insights into the design of nano delivery and may be applied for clinical studies in future.

Effects of grape seed extract on oxidative stress and antioxidant defense markers in streptozotocin-induced diabetic rats.

BACKGROUND/AIM: To evaluate the effects of grape seed extract (GSE) supplementation on oxidative stress and antioxidant markers in streptozotocin (STZ)-induced diabetic rats. MATERIALS AND METHODS: Thirty-six male rats were divided into the following four groups: control, GSE-supplemented control, diabetic, and GSE-supplemented diabetic. Beginning on day 7 after STZ injection, the rats were administered GSE (100 mg kg(-1) day(-1) in drinking water for 6 weeks. At the end of week 6, rats were sacrificed by cardiac puncture. Plasma nitric oxide (NO) levels and xanthine oxidase (XO), adenosine deaminase (ADA), and glutathione peroxidase (GPx) activities were analyzed. RESULTS: Both XO and ADA activities increased and NO levels decreased in diabetic rats (P < 0.05). GSE supplementation normalized all of these changes. Antioxidant enzyme activities decreased in diabetic rats compared to the controls (P < 0.05). GSE supplementation increased antioxidant enzyme activities in both diabetic and healthy rats (P < 0.05). CONCLUSION: These findings suggest that 6 weeks of oral GSE supplementation may prevent oxidative stress and improve antioxidant status in diabetic rats.

Conformational alterations induced by novel green 16-E2-16 gemini surfactant in xanthine oxidase: Biophysical insights from tensiometry, spectroscopy, microscopy and molecular modeling.

Herein we report the interaction of a biodegradable gemini surfactant, ethane-1,2-diyl bis(N,N-dimethyl-N-hexadecylammoniumacetoxy) dichloride (16-E2-16) with bovine milk xanthine oxidase (XO), employing tensiometry, fluorescence spectroscopy, UV spectroscopy, far-UV circular dichroism spectroscopy (CD), Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and computational molecular modeling. Surface tension results depict substantial changes in the micellar as well as interfacial parameters (CMC, ΠCMC, γCMC, Γmax, Amin, ΔGmic° and ΔGads°) of 16-E2-16 gemini surfactant upon XO combination, deciphering the interaction of XO with the gemini surfactant. Fluorescence measurements reveal that 16-E2-16 gemini surfactant causes quenching in the xanthine oxidase (XO) fluorescence spectra via static procedure and the values of various evaluated binding parameters (KSV, Kb, kq, ΔGb° and n) describe that 16-E2-16 effectively binds to XO. Three dimensional fluorescence, 8-anilino-1-naphthalene sulfonic acid (ANS) binding, F1F3 ratio, UV, CD, FTIR, SEM and TEM results delineate changes in the secondary structure of xanthine oxidase. Molecular docking results provide complement to the steady-state fluorescence findings and support the view that quenching occurs due to non-polar environment experienced by aromatic residues of the enzyme. The results of this study can help scientists to tune the conformation of an enzyme (XO) with biocompatible amphiphilic microstructures, which will help to unfold further understanding in the treatment modes of various diseases like gout, hyperuricemia, liver and brain necrosis.

The effect of melatonin on the liver of rats exposed to microwave radiation.

OBJECTIVES: We aimed to clarify if melatonin treatment (2 mg/kg i.p.) may favorably impact the liver tissue in rats exposed to microwave radiation. The experiment was performed on 84 six-weeks-old Wistar male rats exposed for 4h a day, for 20, 40 and 60 days, respectively, to microwaves (900 MHz, 100-300 microT, 54-160 V/m). Rats were divided in to four groups: I (control) - rats treated with saline, II (Mel) - rats treated with melatonin, III (MWs) - microwave exposed rats, IV (MWs + Mel) - MWs exposed rats treated with melatonin. We evaluated oxidative stress parameters (malondialdehyde and carbonyl group content), catalase, xanthine oxidase, deoxyribonuclease I and II activity. BACKGROUND: Oxidative stress is the key mechanism of the microwave induced tissue injury. Melatonin, a lipophilic indoleamine primarily synthesized and released from the pineal gland is a powerful antioxidant. RESULTS: Exposure to microwaves caused an increase in malondialdehyde after 40 (p < 0.01), protein carbonyl content after 20 (p < 0.05), catalase (p < 0.05) and xantine oxidase activity (p < 0.05) after 40 days. Increase in deoxyribonuclease I activity was observed after 60 days (p < 0.05), while deoxyribonuclease II activity was unaffected. Melatonin treatment led to malondialdehyde decrease after 40 days (p< 0.05), but surprisingly had no effect on other analyzed parameters. CONCLUSION: Melatonin exerts certain antioxidant effects in the liver of rats exposed to microwaves, by diminishing the intensity of lipid peroxidation(Fig. 6, Ref. 32).

Uric acid as a biomarker and a therapeutic target in diabetes.

Diabetic nephropathy is a long-standing microvascular complication of diabetes mellitus and is the leading cause of end stage renal disease in developed countries. Current therapeutic strategies used to prevent or delay diabetic nephropathy exert limited clinical protective effects and can have serious adverse effects. Thus, identification of new pharmacologic agents that protect against the initiation and progression of complications of diabetes is of the utmost importance. Uric acid (UA) recently emerged as an inflammatory factor that increases oxidative stress and promotes activation of the renin angiotensin aldosterone system. As a consequence, higher UA levels are associated with various stages of the onset and progression of diabetic nephropathy, including metabolic, cardiovascular and kidney function abnormalities. If UA-lowering drugs, such as the xanthine oxidase inhibitors, block the mechanisms responsible for micro- and macrovascular injury in diabetes, these agents could represent a critical step toward preventing the progression of diabetes. This review focuses on the evidence that supports serum UA levels as a biomarker of renal and cardiovascular risk and as a potential additional therapeutic target in diabetes.

Uric acid promotes left ventricular diastolic dysfunction in mice fed a Western diet.

The rising obesity rates parallel increased consumption of a Western diet, high in fat and fructose, which is associated with increased uric acid. Population-based data support that elevated serum uric acids are associated with left ventricular hypertrophy and diastolic dysfunction. However, the mechanism by which excess uric acid promotes these maladaptive cardiac effects has not been explored. In assessing the role of Western diet-induced increases in uric acid, we hypothesized that reductions in uric acid would prevent Western diet-induced development of cardiomyocyte hypertrophy, cardiac stiffness, and impaired diastolic relaxation by reducing growth and profibrotic signaling pathways. Four-weeks-old C57BL6/J male mice were fed excess fat (46%) and fructose (17.5%) with or without allopurinol (125 mg/L), a xanthine oxidase inhibitor, for 16 weeks. The Western diet-induced increases in serum uric acid along with increases in cardiac tissue xanthine oxidase activity temporally related to increases in body weight, fat mass, and insulin resistance without changes in blood pressure. The Western diet induced cardiomyocte hypertrophy, myocardial oxidative stress, interstitial fibrosis, and impaired diastolic relaxation. Further, the Western diet enhanced activation of the S6 kinase-1 growth pathway and the profibrotic transforming growth factor-ß1/Smad2/3 signaling pathway and macrophage proinflammatory polarization. All results improved with allopurinol treatment, which lowered cardiac xanthine oxidase as well as serum uric acid levels. These findings support the notion that increased production of uric acid with intake of a Western diet promotes cardiomyocyte hypertrophy, inflammation, and oxidative stress that lead to myocardial fibrosis and associated impaired diastolic relaxation.

Allopurinol initiation and change in blood pressure in older adults with hypertension.

Hypertension is a key risk factor for cardiovascular disease, and new treatments are needed. Uric acid reduction lowers blood pressure (BP) in adolescents, suggesting a direct pathophysiological role in the development of hypertension. Whether the same relationship is present in older adults is unknown. We explored change in BP after allopurinol initiation using data from the UK Clinical Practice Research Datalink. Data were extracted for patients with hypertension aged >65 years who were prescribed allopurinol with pretreatment and during treatment BP readings. Data from comparable controls were extracted. The change in BP in patients with stable BP medication was the primary outcome and was compared between groups. Regression analysis was used to adjust for potential confounding factors, and a propensity-matched sample was generated. Three hundred sixty-five patients who received allopurinol and 6678 controls were included. BP fell in the allopurinol group compared with controls (between-group difference in systolic and diastolic BP: 2.1 mm Hg; 95% confidence interval, -0.6 to 4.8; and 1.7 mm Hg; 95% confidence interval, 0.4-3.1, respectively). Allopurinol use was independently associated with a fall in both systolic and diastolic BP on regression analysis (P<0.001). Results were consistent in the propensity-matched sample. There was a trend toward greater fall in BP in the high-dose allopurinol group, but change in BP was not related to baseline uric acid level. Allopurinol use is associated with a small fall in BP in adults. Further studies of the effect of high-dose allopurinol in adults with hypertension are needed.

Effects of aqueous soybean, mistletoe and red clover extracts on activities of adenosine deaminase and xanthine oxidase enzyme.

Soybean (Glycine max), mistletoe (Viscum album) and red clover (Trifolium pratence) have been argued to have anti-cancer effects. In the present study it was aimed to investigate possible effects of these plant extracts on the activities of DNA turn-over enzymes, namely adenosine deaminase (ADA) and xanthine oxidase (XO) in cancerous and non-cancerous gastric and colon tissues. For this aim, 6 cancerous and 6 non-cancerous adjacent human gastric tissues, and 7 cancerous and 7 non-cancerous adjacent colon tissues were obtained by surgical operations. Our results suggest that aqueous soybean, mistletoe and red clover extracts may exhibit anti-tumoral activity by depleting hypoxanthine concentration in the cancer cells through XO activation, which may lead to lowered salvage pathway activity necessary for the cancer cells to proliferate in the cancerous colon tissue. Some foods like soybean, mistletoe and red clover may provide nutritional support to medical cancer therapy through inhibiting and/or activating key enzymes in cancer metabolism (Tab. 4, Ref. 33).

Chemical evidence for potent xanthine oxidase inhibitory activity of Glechoma hederacea var. grandis leaves (kakidoushi-cha).

In this study, chemical evidence for the potent xanthine oxidase inhibitory activity of "kakidoushi-cha" (dry leaves of Glechoma hederacea var. grandis), a traditional folk tea consumed in Japan, was clarified on the basis of structure identification of the active constituents. Assay-guided fractionation and purification afforded 15 compounds from the most active chromatographic fraction of an extract of the tea. Two flavonoids, apigenin and luteolin, showed remarkable inhibitory activity against xanthine oxidase (XO). The contribution of these flavonoid constituents to the observed XO inhibitory activity of the methanol and boiling-water extracts of the tea was estimated to be ca. 35% and ca. 18%, respectively.

Effects of allopurinol on coronary microvascular and left ventricular function in patients with idiopathic dilated cardiomyopathy.

BACKGROUND: Uric acid (UA) is an independent marker of mortality and associated with increased oxidative stress in patients with congestive heart failure (CHF). The present study aimed to investigate the effect of allopurinol on left ventricular (LV) function and coronary microvascular integrity in patients with idiopathic dilated cardiomyopathy (IDC). METHODS: Thirty-nine consecutive IDC patients were divided into 2 groups: elevated (> 7 mg/dL for men and >6.5 mg/dL for women; n = 24) and normal (n = 15) UA. Allopurinol 300 mg per day was given to the elevated UA group. Patients with elevated UA were assessed after a 3-month treatment period. Echocardiography assessing coronary flow reserve (CFR) and systolic and diastolic LV functions were studied. RESULTS: LV ejection fraction was significantly lower in elevated UA group: mean (interquartile range), 32.3% (26.0-36.5%) vs 37.3% (35.5-39.1%) (P < 0.01). Also, CFR and LV diastolic and combined function parameters were more prominently impaired in the elevated UA group. After allopurinol treatment, UA was significantly decreased (7.2 mg/dL [6.8-7.8] to 4.4 mg/dL [3.9-5.8]; P < 0.001) and CFR was markedly improved (1.87 [1.63-2.00] to 2.20 [1.87-2.49]; P < 0.001). The therapeutic effect of allopurinol on the reduction of UA from baseline was directly related to the improvement of CFR (r = 0.49; P = 0.01). Mitral A and E/E' were reduced, while S', E', E/A, and E'/A' were increased significantly. CONCLUSIONS: The present study showed that 3-month treatment with allopurinol was significantly associated with reduced UA levels, and improvement of CFR and LV functions in patients with IDC and hyperuricemia.

Chrysin modulates ethanol metabolism in Wistar rats: a promising role against organ toxicities.

AIMS: Hepato- and nephro-protective efficacy of chrysin was investigated against sequential increase of ethanol intake on the alteration of alcohol metabolizing enzymes-alcohol dehydrogenase (ADH), cytochrome P450 2E1 (CYP 2E1), xanthine oxidase (XO) and oxidant/anti-oxidant status. METHODS: Thirty female Wistar rats segregated into five groups, each with six animals, were put to different doses. Group I as control followed by Group II, III and IV were treated with ethanol (5,8,10 and 12 g/kg body weight per week respectively) for 4 weeks. While Group III and IV were administered with chrysin at 20 mg (D1) and 40 mg/kg body weight (D2), respectively, prior to ethanol administration. Group V was given only chrysin (D2). Various oxidative stress and ethanol metabolizing enzymes were estimated in hepatic and renal tissues. RESULTS: Ethanol administration significantly induced CYP 2E1, ADH and XO in liver and kidneys, respectively, along with an enhancement in levels of malondialdehyde and serum alanine aminotransferase, aspartate aminotransferase, blood urea nitrogen, creatinine and lactate dehydrogenase when compared with the control group and this enhancement is significantly normalized with chrysin administration. Oxidative stress markers: reduced glutathione, glutathione peroxidase, catalase and glutathione reductase were significantly (P < 0.001) depleted in the ethanol-treated group, while chrysin administration significantly restored all of these. Only chrysin administration did not show any adverse effect. CONCLUSION: Results demonstrate that chrysin administration prevents the liver and kidney of Wistar rats against oxidative damage during chronic ethanol consumption by inhibiting the activities of ADH, CYP 2E1, XO and catalase.

Astilbin attenuates hyperuricemia and ameliorates nephropathy in fructose-induced hyperuricemic rats.

Astilbin is a flavonoid compound isolated from the rhizome of Smilax china L. The effects and possible mechanisms of astilbin on hyperuricemia and nephropathy rats were elucidated in this study. Different dosages of astilbin (1.25, 2.5, and 5.0 mg/kg) were administered to 10 % fructose-induced hyperuricemic rats. The results demonstrated that astilbin significantly decreased the serum uric acid (Sur) level by increasing the urinary uric acid (Uur) level and fractional excretion of urate (FEUA) but not inhibiting the xanthine oxidase (XOD) activity. In addition, kidney function parameters such as serum creatinine (Scr) and blood urea nitrogen (BUN) were recovered in astilbin-treated hyperuricemic rats. Further investigation indicated that astilbin prevented the renal damage against the expression of transforming growth factor- ß1 (TGF-ß1) and connective tissue growth factor (CTGF) and also exerted a renal protective role by inhibiting formation of monosodium urate (MSU) and production of prostaglandin E2 (PGE2) and interleukin-1 (IL-1). These findings provide potent evidence for astilbin as a safe and promising lead compound in the development of a disease-modifying drug to prevent hyperuricemia and nephropathy.

Bisphenol A 3,4-quinone induces the conversion of xanthine dehydrogenase into oxidase in vitro.

In the present study, we assessed the influence of bisphenol A (BPA) and bisphenol A 3,4-quinone (BPAQ) on the conversion of xanthine dehydrogenase (XD) into xanthine oxidase (XO) in the rat liver in vitro. BPA up to 100 micromol/L did not affect the XO and XD activities in the partially purified cytosolic fraction from rat liver, whereas BPAQ (2-10 micromol/L) dose-dependently enhanced the XO activity concomitant with a decrease in the XD activity, implying that BPAQ, but not BPA, can convert XD into the reactive oxygen species (ROS) producing the form XO. Furthermore, it was found that BPAQ could increase the generation of ROS and oxidize the guanine moiety of deoxyguanosine in the DNA of primary rat hepatocyte cultures. These results suggest that BPAQ has the potential to convert XD into XO in the liver, which in turn may lead to ROS generation and oxidative DNA damage in this region.

Glutarimide alkaloids and a terpenoid benzoquinone from Cordia globifera.

Three new compounds, a meroterpene (2) having a cyclopropane moiety named globiferane and glutarimide alkaloids named cordiarimides A (3) and B (4), were isolated from the roots of Cordia globifera. Compounds 2-4 exhibited weak cytotoxic activity. Cordiarimide B (4) exhibited radical scavenging activity, as it inhibited superoxide anion radical formation in the xanthine/xanthine oxidase (XXO) assay, and also suppressed superoxide anion generation in differentiated HL-60 human promyelocytic leukemia cells when induced by 12-O-tetradecanoylphorbol-13-acetate (TPA). This is the first report on the presence of glutarimide alkaloids in the genus Cordia.

Uric acid-lowering treatment with benzbromarone in patients with heart failure: a double-blind placebo-controlled crossover preliminary study.

BACKGROUND: Hyperuricemia is common in chronic heart failure (CHF), and it is a strong independent marker of prognosis. Upregulated xanthine oxidase (XO) activity and impaired renal excretion have been shown to account for increased serum uric acid (UA) levels in CHF. Therapeutic interventions with allopurinol to reduce UA levels by XO inhibition have been shown to be beneficial. Discussions are ongoing whether UA itself is actively involved or it is a mere marker of upregulated XO activity within CHF pathophysiology. Therefore, the aim of this study was to test the effect of lowering UA by uricosuric treatment without XO inhibition on hemodynamic and metabolic characteristics of CHF. Impaired renal excretion of UA was taken into account. METHODS AND RESULTS: Serum UA (SUA), urinary UA (uUA) excretion, and renal clearance test for UA (Cl(UA)) were measured in 82 patients with CHF. SUA was significantly increased compared with controls of similar age (control, 5.45+/-0.70 mg/dL; New York Heart Association I, 6.48+/-1.70 mg/dL; New York Heart Association II, 7.34+/-1.94 mg/dL; New York Heart Association III, 7.61+/-2.11 mg/dL; P<0.01). Patients with CHF showed lower uUA excretion and Cl(UA). On multivariate analysis, insulin, brain natriuretic peptide (P<0.01), and creatinine levels (P=0.05) showed independent correlation with SUA. The treatment effect of the uricosuric agent benzbromarone was tested in 14 patients with CHF with hyperuricemia in a double-blind, placebo-controlled, randomized crossover study design. Benzbromarone significantly decreased SUA (P<0.01). Brain natriuretic peptide, left ventricular ejection fraction, and dimensions in echocardiographic assessment did not change after benzbromarone therapy. In contrast, fasting insulin (placebo, 18.8+/-8.9 microU/mL; benzbromarone, 11.0+/-6.2 microU/mL; P<0.05), homeostasis model assessment of insulin resistance index (placebo, 5.4+/-2.6; benzbromarone, 3.0+/-1.7; P<0.05), and tumor necrosis factor-alpha (placebo, 2.59+/-0.63 pg/mL; benzbromarone, 2.14+/-0.51 pg/mL; P<0.05) improved after benzbromarone, and the changes in tumor necrosis factor-alpha levels were correlated with reduction of SUA (P<0.05). CONCLUSIONS: These results show that UA lowering without XO inhibition may not have an effect on hemodynamic impairment in CHF pathophysiology. To the extent that these data are correct, this finding suggests that upregulated XO activity rather than UA itself is actively involved in hemodynamic impairment in CHF. Clinical Trial Registration- clinical trials.gov. Identifier: NCT00422318.

In response to oxidative stress, the expression of inflammatory cytokines and antioxidant enzymes are impaired in placenta, but not adipose tissue, of women with gestational diabetes.

In response to oxidative stress, gestational diabetes mellitus (GDM) placenta releases less 8-isoprostane and tumour necrosis factor (TNF) alpha. The effect of oxidative stress on other cytokines and antioxidant gene expressions are unknown. The aim of this study is to further explore the antioxidant status and effect of oxidative stress in GDM tissue. Human placenta, omental and subcutaneous adipose tissue from women with and without GDM were exposed to hypoxanthine (HX)/xanthine oxidase (XO). Cytokine release was analysed by ELISA and cytokine and antioxidant gene expression by RT-PCR. Catalase (CAT) and glutathione reductase (GSR) mRNA expression was higher in GDM (n=18) compared with normal (n=23) placenta. There was no difference in glutathione peroxidase and superoxide dismutase mRNA expression. Antioxidant gene expression was unaltered between normal (n=18) and GDM (n=10) adipose tissue. HX/XO treatment significantly stimulated cytokine release (13/16 cytokines) and cytokine mRNA expression, and decreased antioxidant gene expression (CAT and GSR) in human placenta from normal pregnant women. In GDM placenta, HX/XO only significantly increased the release of 3/16 cytokines, while there was no effect on antioxidant gene expression. In normal and GDM adipose tissues, HX/XO increased proinflammatory cytokine and 8-isoprostane release, while there was no change in antioxidant gene expression. GDM placenta is characterised by increased antioxidant gene expression, and is less responsive to exogenous oxidative stress than tissues obtained from normal pregnant women. This may represent a protective or adaptive mechanism to prevent damage from further oxidative insult in utero as indicated by increased tissue antioxidant expression.

Six-month, prospective, longitudinal, open-label caffeine and dextromethorphan phenotyping study in children with growth hormone deficiency receiving recombinant human growth hormone replacement.

BACKGROUND: Recombinant human growth hormone (r-hGH) is increasingly being used in children. Although growth hormone (GH) may alter the clearance of concomitantly administered medications, its effects on individual drug-metabolizing enzymes in children have not been characterized. OBJECTIVE: The goal of this study was to assess the activities of cytochrome P450 (CYP) 1A2, N-acetyltransferase 2, xanthine oxidase, and CYP2D6 in children with isolated idiopathic GH deficiency before and 3 and 6 months after initiation of r-hGH treatment. METHODS: This 6-month, prospective, longitudinal, open-label phenotyping study was conducted at 4 academic tertiary care centers within the Pediatric Pharmacology Research Unit network. Prepubertal or early pubertal children (4-14 years) with short stature and isolated idiopathic GH deficiency were enrolled. Patients were given 4 ounces of a cola beverage and 0.5 mg/kg of dextromethorphan (DM) before and 3 and 6 months after initiation of r-hGH treatment. Urine was collected for 8 hours after probe substrate administration, and enzyme activity was assessed using validatedcaffeine/metaboliteandDM/metabolitemolar ratios. Patients with a DM/dextrorphan molar ratio > or =0.3 were classified as poor metabolizers, and those with a ratio <0.3 were classified as extensive metabolizers. Anthropometric and biochemical responses were assessed at each visit. Blood was also obtained for determination of serum insulinlike growth factor-1 (IGF-1) levels and CYP2D6 genotype. RESULTS: Fourteen patients (mean [SD] age, 11.5 [2.6] years [age range, 4.5-14.6 years]; 11 males, 3 females; 100% white; median height and weight, 131.8 cm and 29.2 kg, respectively) completed the 3 study visits. However, data from 2 patients were excluded from analysis due to procedural violations. In all patients, growth velocity and serum IGF-1 concentrations were significantly higher (P < 0.001) after r-hGH treatment (mean doses, 0.32 and 0.33 mg/kg per week at 3 and 6 months, respectively). However, molar ratio values did not significantly change after initiation of r-hGH. CONCLUSIONS: In this study population of children with isolated idiopathic GH deficiency, no significant differences in caffeine/metabolite and DM/metabolite molar ratios were observed after initiation of r-hGH treatment.