Arginase 1/2 Inhibitor OATD-02: From Discovery to First-in-man Setup in Cancer Immunotherapy.

Pharmacologic inhibition of the controlling immunity pathway enzymes arginases 1 and 2 (ARG1 and ARG2) is a promising strategy for cancer immunotherapy. Here, we report the discovery and development of OATD-02, an orally bioavailable, potent arginases inhibitor. The unique pharmacologic properties of OATD-02 are evidenced by targeting intracellular ARG1 and ARG2, as well as long drug-target residence time, moderate to high volume of distribution, and low clearance, which may jointly provide a weapon against arginase-related tumor immunosuppression and ARG2-dependent tumor cell growth. OATD-02 monotherapy had an antitumor effect in multiple tumor models and enhanced an efficacy of the other immunomodulators. Completed nonclinical studies and human pharmacokinetic predictions indicate a feasible therapeutic window and allow for proposing a dose range for the first-in-human clinical study in patients with cancer. SIGNIFICANCE: We have developed an orally available, small-molecule intracellular arginase 1 and 2 inhibitor as a potential enhancer in cancer immunotherapy. Because of its favorable pharmacologic properties shown in nonclinical studies, OATD-02 abolishes tumor immunosuppression induced by both arginases, making it a promising drug candidate entering clinical trials.

Pharmacokinetic Drug Interaction Study of Sorafenib and Morphine in Rats.

A combination of the tyrosine kinase inhibitor-sorafenib-and the opioid analgesic-morphine-can be found in the treatment of cancer patients. Since both are substrates of P-glycoprotein (P-gp), and sorafenib is also an inhibitor of P-gp, their co-administration may affect their pharmacokinetics, and thus the safety and efficacy of cancer therapy. Therefore, the aim of this study was to evaluate the potential pharmacokinetic drug-drug interactions between sorafenib and morphine using an animal model. The rats were divided into three groups that Received: sorafenib and morphine (ISOR+MF), sorafenib (IISOR), and morphine (IIIMF). Morphine caused a significant increase in maximum plasma concentrations (Cmax) and the area under the plasma concentration-time curves (AUC0-t, and AUC0-∞) of sorafenib by 108.3 (p = 0.003), 55.9 (p = 0.0115), and 62.7% (p = 0.0115), respectively. Also, the Cmax and AUC0-t of its active metabolite-sorafenib N-oxide-was significantly increased in the presence of morphine (p = 0.0022 and p = 0.0268, respectively). Sorafenib, in turn, caused a significant increase in the Cmax of morphine (by 0.5-fold, p = 0.0018). Moreover, in the presence of sorafenib the Cmax, AUC0-t, and AUC0-∞ of the morphine metabolite M3G increased by 112.62 (p < 0.0001), 46.82 (p = 0.0124), and 46.78% (p = 0.0121), respectively. Observed changes in sorafenib and morphine may be of clinical significance. The increased exposure to both drugs may improve the response to therapy in cancer patients, but on the other hand, increase the risk of adverse effects.

Serum indoxyl sulphate and its relation to albumin and α1-acid glycoprotein as a potential biomarkers of maternal intestinal metabolism during pregnancy and postpartum.

BACKGROUND: Serum indoxyl sulfate (IS) levels depend on the production of indole in the gut. The biological effects of IS in the vascular bed could be confirmed by changes in the levels of individual serum proteins during normal pregnancy and in the postpartum period as compared with non-pregnant controls. Albumin (Alb) and α1-acid glycoprotein (AGP, orosomucoid) are the most abundant serum carrier proteins with potential interrelationships with serum levels of IS. METHODS: Serum levels of IS, Alb and AGP were measured in 84 pregnant women in the first, second and third trimester of pregnancy and in the postpartum period, as well as in non-pregnant controls (n = 20), using ultra-performance liquid chromatography (UPLC) coupled to mass spectrometry (IS), colorimetric assay (Alb) and immunoturbidimetric assay (AGP). RESULTS: The postpartum serum levels [mg/L] of IS were lower (p = 0.027) than in the second trimester (mean±SD: 0.85±0.39 vs 0.58±0.32). There were no differences in the IS to ALB ratio calculated in the three trimesters of pregnancy, the postpartum period, and in the non-pregnant controls. The IS/AGP ratio increased from the first to the second trimester (p = 0.039), and decreased in the postpartum period (p<0.05), when it was lower than in the second and third trimester. CONCLUSIONS: The variability of the serum IS/AGP ratio during pregnancy and in the postpartum period may reflect shared involvement in the regulation of their intravascular relationships. The link between serum levels of IS derived from the gut and AGP could serve a potential biomarkers of maternal intestinal metabolism during pregnancy and postpartum.

A comprehensive method for determining cellular uptake of purine nucleoside phosphorylase and adenylosuccinate synthetase inhibitors by H. pylori.

Due to the growing number of Helicobacter pylori strains resistant to currently available antibiotics, there is an urgent need to design new drugs utilizing different molecular mechanisms than those that have been used up to now. Enzymes of the purine salvage pathway are possible targets of such new antibiotics because H. pylori is not able to synthetize purine nucleotides de novo. The bacterium's recovery of purines and purine nucleotides from the environment is the only source of these essential DNA and RNA building blocks. We have identified formycins and hadacidin as potent inhibitors of purine nucleoside phosphorylase (PNP) and adenylosuccinate synthetase (AdSS) from H. pylori - two key enzymes of the purine salvage pathway. However, we have found that these compounds are not effective in H. pylori cell cultures. To address this issue, we have developed a universal comprehensive method for assessing H. pylori cell penetration by drug candidates, with three alternative detection assays. These include liquid chromatography tandem mass spectrometry, UV absorption, and inhibition of the target enzyme by the tested compound. Using this approach, we have shown that cellular uptake by H. pylori of formycins and hadacidin is very poor, which reveals why their in vitro inhibition of PNP and AdSS and their effect on H. pylori cell cultures are so different. The cell penetration assessment method developed here will be extremely useful for validating the cellular uptake of other drug candidates, facilitating the design of new potent therapeutic agents against H. pylori. KEY POINTS: • A method for assessing H. pylori cells penetration by drug candidates is described. • Three alternative detection assays that complement each other can be used. • The method may be adapted for other bacteria as well.

Trimethylamine N-Oxide, a Gut Microbiota-Derived Metabolite, Is Associated with Cardiovascular Risk in Psoriasis: A Cross-Sectional Pilot Study.

INTRODUCTION: Trimethylamine N-oxide (TMAO), a gut microbiota metabolite from dietary phosphatidylcholine, is involved in the pathogenesis of atherosclerosis and cardiovascular diseases. Psoriasis is associated with increased cardiovascular risk that is not captured by traditional biomarkers. The aim of the present study was to assess TMAO concentration in psoriasis and evaluate the relationship between TMAO and cardiovascular risk in psoriatic patients. METHODS: In 72 patients with psoriasis and 40 age- and sex-matched non-psoriatic controls, we evaluated fasting plasma TMAO, measured by high-performance liquid chromatography, and cardiovascular risk assessed by various scoring systems such as Framingham, QRISK2, AHA/ACC, and Reynolds risk scores. RESULTS: In patients with psoriasis, TMAO concentration was significantly higher than in the control group (195.68 [133.54-332.58] ng/ml versus 126.06 [84.29-156.88] ng/ml, respectively; p < 0.001). Plasma TMAO concentration was significantly correlated with age, total cholesterol, triglycerides, systolic and diastolic blood pressure. Furthermore, the receiver-operating characteristic (ROC) and multiple regression analysis showed that TMAO is an independent predictor of cardiovascular risk. CONCLUSION: TMAO is a valuable candidate for biomarker and a translational link between dysbiosis and atherosclerosis in psoriasis.

Clinical Implications of Intestinal Barrier Damage in Psoriasis.

BACKGROUND: An increasing amount of evidence suggests an association between increased intestinal permeability and the pathogenesis of chronic inflammatory diseases. However, the clinical significance of gut barrier dysfunction in psoriasis remains to be established. OBJECTIVE: To evaluate whether there are differences in disease activity, the severity of gastrointestinal symptoms and the blood concentration of bacterial metabolites in psoriatic patients with a normal and altered intestinal barrier. PATIENTS AND METHODS: Gut barrier integrity was assessed with the serum concentrations of claudin-3, a modulator of intestinal tight junctions and an intestinal fatty acid-binding protein, a marker of enterocyte damage. Gastrointestinal symptoms were evaluated with a validated questionnaire. The concentration of trimethylamine N-oxide (TMAO), a gut microbiota-associated metabolite, was measured with high-performance liquid chromatography. RESULTS: One hundred and fourteen patients with psoriasis were finally enrolled in the study - 68 with an altered gut barrier and 46 with a properly functioning intestinal barrier. Patients with an altered gut barrier showed a significantly higher score in the Gastrointestinal Symptom Rating Scale (3.20 vs 1.46, p<0.001). Moreover, patients with psoriasis and a disrupted intestinal barrier demonstrated a higher disease activity (PASI: 19.7 vs 10.3, p<0.001) and systemic inflammatory parameters (neutrophil-to-lymphocyte ratio: 2.86 vs 1.71, p<0.001; C-reactive protein 3.76 vs 1.92; p<0.05). The marker of bacterial translocation was significantly higher in psoriatic patients with damaged gut integrity (TMAO: 375.7±51.9 vs 119.4±27.5 ng/mL; p<0.05). CONCLUSION: The altered gut barrier in psoriasis is associated with gastrointestinal symptoms, systemic inflammatory profile and the increased blood concentration of gut microbiota-derived metabolite - TMAO. Intestinal barrier modulation represents a new promising therapeutic approach.

In vivo assessment of potential for UGT-inhibition-based drug-drug interaction between sorafenib and tapentadol.

Sorafenib (SR) is one of the most potent UGT (1A1, 1A9) inhibitors (in in vitro tests). The inhibition of UGT1A1 may cause hyperbilirubinaemia, whereas the inhibition of UGT1A9 and 1A1 may result in drug-drug interactions (DDIs). Tapentadol (TAP) is a synthetic µ-opioid agonist and is used to treat moderate to severe acute pain. Tapentadol is highly glucuronidated by the UGT1A9 and UGT2B7 isoenzymes. The aim of the study was to assess the DDI between SR and TAP. Wistar rats were divided into three groups, with eight animals in each. The rats were orally treated with SR (100 mg/kg) or TAP (4.64 mg/kg) or in combination with 100 mg/kg SOR and 4.64 TAP mg/kg. The concentrations of SR and sorafenib N-oxide, TAP and tapentadol glucuronide were respectively measured by means of high-performance liquid chromatography (HPLC) with ultraviolet detection and by means of ultra-performance liquid chromatography-tandem mass spectrometry. The co-administration of TAP with SR caused TAP maximum plasma concentration (Cmax) to increase 5.3-fold whereas its area under the plasma concentration-time curve (AUC0-∞) increased 1.5-fold. The tapentadol glucuronide Cmax increased 5.3-fold and whereas its AUC0-∞ increased 2.0-fold. The tapentadol glucuronide/TAP AUC0-∞ ratio increased 1.4-fold (p = 0.0118). TAP also increased SR Cmax 1.9-fold, whereas its AUC0-∞ increased 1.3-fold. The sorafenib N-oxide Cmax increased 1.9-fold whereas its AUC0-∞ increased 1.3-fold. The sorafenib N-oxide/SR AUC0-t ratio increased 1.4-fold (p = 0.0127). The results show that the co-administration of sorafenib and tapentadol increases the exposure to both drugs and changes their metabolism. In consequence, the pharmacological effect may be intensified, but the toxicity may increases, too.

Higher Concentrations of Cyclosporine Metabolites in Liver Transplant Recipients With a History of Viral and Bacterial Infections.

BACKGROUND: Infection remains a serious clinical problem in liver transplant (LTX) recipients. A higher risk of infection is connected with immunosuppression therapy. The aim of the study was to assess the relationships between infections' incidence and concentrations of cyclosporine (CsA) metabolites after LTX. METHODS: Forty-three liver transplant recipients receiving CsA were included in the study. With the use of liquid chromatography combined with tandem mass spectrometry, concentrations of CsA and its metabolites were measured: dihydroxylated cyclosporine metabolites (DiHCsA), trihydroxylated cyclosporine metabolites (TriHCsA), demethylcarboxylated cyclosporine metabolites (DemCarbCsA), AM1, AM9, and AM4N. The study protocol conformed with the Declaration of Helsinki. RESULTS: Patients with a history of Epstein-Barr virus (EBV) infection had higher DiHCsA, TriHCsA, DemCarbCsA, AM1/CsA, DiHCsA/CsA, TriHCsA/CsA i DemCarbCsA/CsA in comparison with group without such infection (P = .049, P = .037, P = .006, P = .018, P = .005, P = .027, and P = .026, respectively). LTX recipients with a history of all viral infections had higher DiHCsA, TriHCsA, DiHCsA/CsA, TriHCsA/CsA than patients without viral infections (P = .013, P = .021, P = .013, and P = .048, respectively). Multivariable analysis showed that AM1, DiHCsA, TriHCsA, DemCarbCsA, AM4N/CsA had positively influence on the incidence of all viral infections (ß = 0.0302, P = .0328; ß = 0.0699, P = .0453; ß = 0.6781, P = .0382; ß = 0.6767, P = .0414; and ß = 0.8307, P = .0267, respectively). In multivariable analysis, patients with a history of all bacterial infections had higher AM1 and higher AM1/CsA in comparison with LTX recipients without such infections (ß = 0.0118, P = .0279; and ß = 0.0099, P = .036, respectively). CONCLUSION: In liver transplant recipients with a history of viral or bacterial infections higher concentrations of CsA metabolites were found. Possibly CsA metabolites could be used to assess the risk of infection in patients after liver transplantation. It should be confirmed in further investigations.

Absorption of Polyunsaturated Fatty Acid (PUFA) Is Related to IgG Blood Levels of Neonatal Pigs during the First 48 Hours Postpartum.

The current study is aimed at highlighting the impact of enterally or parenterally applied immunoglobulins (Igs) on polyunsaturated fatty acid (PUFA) absorption in newborn pigs. Piglets were chosen as the appropriate model since they are born agammaglobulinemic and any effects of Ig addition can thus be easily monitored. Twenty-one, new born piglets were used in the study. Plasma levels of PUFAs, ARA, DHA, and EPA dropped (similarly to that seen in human infants) by between 40 and 50% in newborn, unsuckled piglets fed an infant formula for 48 h. However, piglets fed the same infant formula but supplied with immunoglobulins (Igs) either orally, by feeding piglets with swine or bovine colostrum, or intravenously, by i.u.a. (intraumbilical artery) infusion of swine or human Ig preparations or swine serum, demonstrated improved growth and PUFA levels similar to those observed at birth. The significant positive correlation was found between the body weight gain, as well as levels of ARA and EPA, and plasma immunoglobulins concentration. These results indicate the importance of the presence of Ig in the blood for appropriate absorption of dietary PUFAs and probably other nutrients in newborn piglets. This may have an impact on the dietary guidelines for human neonates, especially those born prematurely with low plasma Ig levels, since PUFAs are important factors for brain development in early life.

Expression of maize calcium-dependent protein kinase (ZmCPK11) improves salt tolerance in transgenic Arabidopsis plants by regulating sodium and potassium homeostasis and stabilizing photosystem II.

In plants, CALCIUM-DEPENDENT PROTEIN KINASES (CDPKs/CPKs) are involved in calcium signaling in response to endogenous and environmental stimuli. Here, we report that ZmCPK11, one of maize CDPKs, participates in salt stress response and tolerance. Salt stress induced expression and upregulated the activity of ZmCPK11 in maize roots and leaves. Activation of ZmCPK11 upon salt stress was also observed in roots and leaves of transgenic Arabidopsis plants expressing ZmCPK11. The transgenic plants showed a long-root phenotype under control conditions and a short-root phenotype under NaCl, abscisic acid (ABA) or jasmonic acid (JA) treatment. Analysis of ABA and JA content in roots indicated that ZmCPK11 can mediate root growth by regulating the levels of these phytohormones. Moreover, 4-week-old transgenic plants were more tolerant to salinity than the wild-type plants. Their leaves were less chlorotic and showed weaker symptoms of senescence accompanied by higher chlorophyll content and higher quantum efficiency of photosystem II. The expression of Na+ /K+ transporters (HKT1, SOS1 and NHX1) and transcription factors (CBF1, CBF2, CBF3, ZAT6 and ZAT10) with known links to salinity tolerance was upregulated in roots of the transgenic plants upon salt stress. Furthermore, the transgenic plants accumulated less Na+ in roots and leaves under salinity, and showed a higher K+ /Na+ ratio in leaves. These results show that the improved salt tolerance in ZmCPK11-transgenic plants could be due to an upregulation of genes involved in the maintenance of intracellular Na+ and K+ homeostasis and a protection of photosystem II against damage.

Dose-adjusted and dose/kg-adjusted concentrations of mycophenolic acid precursors reflect metabolic ratios of their metabolites in contrast with tacrolimus and cyclosporine.

BACKGROUND AND PURPOSE: Therapeutic drug monitoring is a valuable tool supporting immunosuppressive therapy. Significant variation of immunosuppressive drug (ISD) concentrations during their use at similar doses is the basis of dose-normalization strategy. The strategy of dose-adjustment is proposed to identify variability in the rate of ISD metabolism. While the parent drug-to-metabolite ratio (metabolic ratio, MR) represents the rate of formation of individual metabolites. The present study was aimed at evaluation of associations between ISDs' metabolism rate expressed as dose-adjusted concentrations (C/D) and dose/kg-adjusted concentrations (C/D/kg) and MRs of individual metabolites of tacrolimus, cyclosporine A and MPA precursors. EXPERIMENTAL APPROACH: 506 patients have participated: 284 males (56.13%) and 222 females (43.87%); 318 after kidney (62.85%) and 188 after liver transplantation; median age was 51.34 (39.32-59.95) years and median time after transplantation 78.92 (33.87-138.4) months. KEY RESULTS: Generally, we have not observed significant relationships between dose-adjusted and dose/kg-adjusted concentrations and MRs of cyclosporine and tacrolimus. Significant correlations were found for: AM9/CsA and dMC-CsA/CsA in kidney transplant recipients and MIII/Tac, AM1/CsA and AM4N/CsA in liver transplant recipients. In contrast, MRs of mycophenolic acid (MPA) metabolites correlated significantly with MPA C/D and C/D/kg both in kidney and liver transplant recipients. CONCLUSION AND IMPLICATIONS: In conclusion, easily available and easy to use in clinical practice C/D and C/D/kg ratios cannot be considered as parameters directly reflecting the rate of generation of major metabolites of cyclosporine and tacrolimus both in liver and kidney transplant recipients.

Cyclosporine Metabolites' Metabolic Ratios May Be Markers of Cardiovascular Disease in Kidney Transplant Recipients Treated with Cyclosporine A-Based Immunosuppression Regimens.

Cardiovascular disease (CVD) remains one of the primary causes of death after kidney transplantation (KTX). Cyclosporine (CsA) metabolites may play a role in CVD. Metabolic ratio (MR) may be considered a measure of intra-individual differences of CsA metabolism. The study was aimed at analysis of associations of CVD with indices of CsA metabolism: MRs and dose-adjusted CsA concentrations (C/D and C/D/kg). The study was performed in the Department of Immunology, Transplant Medicine, and Internal Diseases of the Medical University of Warsaw and involved 102 KTX recipients. Whole blood concentrations of cyclosporine A, AM1, AM9, AM4N, demethylcarboxylated (dMC-CsA), dihydroxylated (DiH-CsA), trihydroxylated (TriH-CsA) cyclosporine metabolites were determined by liquid chromatography coupled with tandem mass spectrometry. Lower AM9/CsA were observed in diabetics. Patients with coronary disease and/or myocardial infarction had lower dMC-CsA/CsA and higher AM4N/CsA. Supraventricular arrhythmia (SVA) was associated with higher AM1/CsA and AM4N/CsA. Hypertriglyceridemia (hTG) was associated with lower AM9/CsA, higher C/D and C/D/kg. Decrease of AM9/CsA and AM4N and higher D/C were associated with overweight/obesity. Systolic blood pressure (BP) positively correlated with dMC-CsA/CsA and negatively with C/D/kg. Diastolic BP correlated positively with AM1/CsA, dMC-CsA/CsA, DiH-CsA/CsA and TriH-CsA/CsA. We have demonstrated the association of coronary disease/myocardial infarction, SVA, hTG, overweight/obesity and elevated arterial BP with higher MRs of AM1, AM4N, dMC-CsA, DiH-CsA and TriH-CsA, and lower MRs of AM9, which may indicate deleterious and favourable effects of individual CsA metabolites on cardiovascular system and suggest engagement of specific enzymatic pathways.

Cerebrovascular reactivity and cerebral perfusion of rats with acute liver failure: role of L-glutamine and asymmetric dimethylarginine in L-arginine-induced response.

Cerebral blood flow (CBF) is impaired in acute liver failure (ALF), however, the complexity of the underlying mechanisms has often led to inconclusive interpretations. Regulation of CBF depends at least partially on variations in the local brain L-arginine concentration and/or its metabolic rate. In ALF, other factors, like an increased concentration of asymmetric dimethylarginine (ADMA), an endogenous nitric oxide synthase inhibitor and elevated level of L-glutamine, may contribute to CBF alteration. This study demonstrated strong differences in the reactivity of the middle cerebral arteries and their response to extravascular L-arginine application between vessels isolated from rats with thioacetamide (TAA)-induced ALF and control animals. Our results also showed the decrease in the cerebral perfusion in TAA rats measured by arterial spin labeling perfusion magnetic resonance. Subsequently, we aimed to investigate the importance of balance between the concentration of ADMA and L-arginine in the CBF regulation. In vivo, intraperitoneal L-arginine administration in TAA rats corrected: (i) decrease in cerebral perfusion, (ii) decrease in brain extracellular L-arginine/ADMA ratio and (iii) increase in brain L-glutamine concentration. Our study implicates that impaired vascular tone of cerebral arteries is most likely associated with exposure to high ADMA and L-glutamine levels resulting in limited availability of L-arginine and might be responsible for reduced cerebral perfusion observed in ALF.

Ammonia Reduces Intracellular Asymmetric Dimethylarginine in Cultured Astrocytes Stimulating Its y⁺LAT2 Carrier-Mediated Loss.

Previously we had shown that ammonia stimulates nitric oxide (NO) synthesis in astrocytes by increasing the uptake of the precursor amino acid, arginine via the heteromeric arginine/glutamine transporter y⁺LAT2. Ammonia also increases the concentration in the brain of the endogenous inhibitor of nitric oxide synthases (NOS), asymmetric dimethylarginine (ADMA), but distribution of ADMA surplus between the intraastrocytic and extracellular compartments of the brain has not been studied. Here we tested the hypothesis that ammonia modulates the distribution of ADMA and its analog symmetric dimethylarginine (SDMA) between the two compartments of the brain by competition with arginine for the y⁺LAT2 transporter. In extension of the hypothesis we analyzed the ADMA/Arg interaction in endothelial cells forming the blood-brain barrier. We measured by high-performance liquid chromatography (HPLC) and mass spectrometry (MS) technique the concentration of arginine, ADMA and SDMA in cultured cortical astrocytes and in a rat brain endothelial cell line (RBE-4) treated with ammonia and the effect of silencing the expression of a gene coding y⁺LAT2. We also tested the expression of ADMA metabolism enzymes: protein arginine methyltransferase (PRMT) and dimethylarginine dimethyl aminohydrolase (DDAH) and arginine uptake to astrocytes. Treatment for 48 h with 5 mM ammonia led to an almost 50% reduction of ADMA and SDMA concentration in both cell types, and the effect in astrocytes was substantially attenuated by silencing of the Slc7a6 gene. Moreover, the y⁺LAT2-dependent component of ammonia-evoked arginine uptake in astrocytes was reduced in the presence of ADMA in the medium. Our results suggest that increased ADMA efflux mediated by upregulated y⁺LAT2 may be a mechanism by which ammonia interferes with intra-astrocytic (and possibly intra-endothelial cell) ADMA content and subsequently, NO synthesis in both cell types.

Total testosterone to dihydrotestosterone ratio assessed by LC-MS/MS predicts a worse metabolic profile not only in PCOS patients.

OBJECTIVES: Total testosterone/dihydrotestosterone ratio (TT/DHT) was found to determine metabolic risk in polycystic ovary syndrome (PCOS). The aim of this study was to analyze whether (TT/DHT) may be helpful in predicting metabolic risk not only in PCOS patients but also in healthy women. MATERIAL AND METHODS: Total testosterone (TT), dihydrotestosterone (DHT), androstendione and dehydroepiandrosterone sulphate (DHEA-S) were measured by LC-MS/MS in 36 women with PCOS and in 29 age-matched controls without clinical hyperandrogenism. In all participants, anthropometric data, lipids, adipose tissue percent (%fat), HOMA-IR were also assessed. RESULTS: The studied groups were not different in terms of age, BMI, waist circumference, %fat and HOMA-IR. In the patients group, mean TT and androstendione levels were significantly higher as compared to controls (1.4 nmol/L vs. 1.0 nmol/L, P < 0.001) and (6.6 nmol/L vs. 4.9 nmol/L, P < 0.01), respectively. In the patients group, mean TT/DHT ratio was significantly higher compared to controls (3.6 vs. 2.7, P < 0.01) and correlated with BMI (r = 0.37, P < 0.05), waist circumference (r = 0.44, P < 0.01), %fat (r = 0.30, P < 0.05), as well as with insulin levels (r = 0.38, P < 0.05) and HOMA-IR (r = 0.44, P < 0.05). The association between TT/DHT ratio and unfavorable metabolic parameters was also seen in controls. CONCLUSION: Total testosterone/dihydrotestosterone ratio assessed by LC-MS/MS correlates with a worse metabolic profile not only in PCOS patients, but also in healthy women.

Intracerebral Administration of S-Adenosylhomocysteine or S-Adenosylmethionine Attenuates the Increases in the Cortical Extracellular Levels of Dimethylarginines Without Affecting cGMP Level in Rats with Acute Liver Failure.

Alterations in brain nitric oxide (NO)/cGMP synthesis contribute to the pathogenesis of hepatic encephalopathy (HE). An increased asymmetrically dimethylated derivative of L-arginine (ADMA), an endogenous inhibitor of NO synthases, was observed in plasma of HE patients and animal models. It is not clear whether changes in brain ADMA reflect its increased local synthesis therefore affecting NO/cGMP pathway, or are a consequence of its increased peripheral blood content. We measured extracellular concentration of ADMA and symmetrically dimethylated isoform (SDMA) in the prefrontal cortex of control and thioacetamide (TAA)-induced HE rats. A contribution of locally synthesized dimethylarginines (DMAs) in their extracellular level in the brain was studied after direct infusion of the inhibitor of DMAs synthesizing enzymes (PRMTs), S-adenosylhomocysteine (AdoHcy, 2 mM), or the methyl donor, S-adenosylmethionine (AdoMet, 2 mM), via a microdialysis probe. Next, we analyzed whether locally synthesized ADMA attains physiological significance by determination of extracellular cGMP. The expression of PRMT-1 was also examined. Concentration of ADMA and SDMA, detected by positive mode electrospray LC-DMS-MS/MS, was greatly enhanced in TAA rats and was decreased (by 30 %) after AdoHcy and AdoMet infusion. TAA-induced increase (by 40 %) in cGMP was unaffected after AdoHcy administration. The expression of PRMT-1 in TAA rat brain was unaltered. The results suggest that (i) the TAA-induced increase in extracellular DMAs may result from their effective synthesis in the brain, and (ii) the excess of extracellular ADMA does not translate into changes in the extracellular cGMP concentration and implicate a minor role in brain NO/cGMP pathway control.

Limited predictive value of achieving beneficial plasma (Z)-endoxifen threshold level by CYP2D6 genotyping in tamoxifen-treated Polish women with breast cancer.

BACKGROUND: Tamoxifen, the most frequently used drug for treating estrogen receptor-positive breast cancer, must be converted into active metabolites to exert its therapeutic efficacy, mainly through CYP2D6 enzymes. The objective of this study was to investigate the impact of CYP2D6 polymorphisms on (Z)-endoxifen-directed tamoxifen metabolism and to assess the usefulness of CYP2D6 genotyping for identifying patients who are likely to have insufficient (Z)-endoxifen concentrations to benefit from standard therapy. METHODS: Blood samples from 279 Polish women with breast cancer receiving tamoxifen 20 mg daily were analyzed for CYP2D6 genotype and drug metabolite concentration. Steady-state plasma levels of tamoxifen and its 14 metabolites were measured by using the ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method. RESULTS: In nearly 60 % of patients, including over 30 % of patients with fully functional CYP2D6, (Z)-endoxifen concentration was below the predefined threshold of therapeutic efficacy. The most frequently observed CYP2D6 genotype was EM/PM (34.8 %), among which 83.5 % of patients had a combination of wild-type and *4 alleles. Plasma concentration of five metabolites was significantly correlated with CYP2D6 genotype. For the first time, we identified an association between decreased (E/Z)-4-OH-N-desmethyl-tamoxifen-ß-D-glucuronide levels (r (2) = 0.23; p < 10(-16)) and increased CYP2D6 functional impairment. The strongest correlation was observed for (Z)-endoxifen, whose concentration was significantly lower in groups of patients carrying at least one CYP2D6 null allele, compared with EM/EM patients. The CYP2D6 genotype accounted for plasma level variability of (Z)-endoxifen by 27 % (p < 10(-16)) and for the variability of metabolic ratio indicating (Z)-endoxifen-directed metabolism of tamoxifen by 51 % (p < 10(-43)). CONCLUSIONS: The majority of breast cancer patients in Poland may not achieve a therapeutic level of (Z)-endoxifen upon receiving a standard dose of tamoxifen. This finding emphasizes the limited value of CYP2D6 genotyping in routine clinical practice for identifying patients who might not benefit from the therapy. In its place, direct monitoring of plasma steady-state (Z)-endoxifen concentration should be performed to personalize and optimize the treatment.

Mycophenolic Acid Metabolites Acyl-Glucuronide and Glucoside Affect the Occurrence of Infectious Complications and Bone Marrow Dysfunction in Liver Transplant Recipients.

BACKGROUND Mycophenolic acid (MPA) prodrugs are anti-proliferative immunosuppressive agents commonly used after organ transplantation. Although they are generally well tolerated by patients, adverse effects may occur. It is postulated that MPA metabolites could also contribute to these adverse effects. MATERIAL AND METHODS The objective of this study was the assessment of concentrations of total MPA and its metabolites, phenyl glucuronide (MPAG), acyl glucuronide (AcMPAG) and glucoside (GluMPA), using liquid chromatography combined with mass spectrometry (LC/MS/MS) in two groups: kidney transplant recipients and liver transplant patients. Associations of MPA and its metabolites with adverse effects were analyzed. RESULTS The study group consisted of 211 recipients of liver or kidney transplants who received immunosuppressive therapy, including MPA prodrugs. Multivariant analysis showed a positive influence of MPA on gastroenterotoxicity in kidney transplant recipients. In liver patients, gastroenterotoxicity was associated with lower MPAG concentrations. A positive influence of AcMPAG on bacterial infections in liver transplant patients was observed. In liver transplant recipients, a positive influence of MPA and a negative influence of GluMPA levels on the PLT count were revealed. MPA and its metabolites did not influence the hemoglobin levels in both groups. There were no significant relationships among MPA, its metabolites and WBC counts. CONCLUSIONS In kidney transplant recipients, total MPA trough concentration is associated with gastroenterotoxicity and its monitoring could have important role in management of gastrointestinal complications. The quantification of AcMPAG in liver recipients receiving MPA may be helpful in avoiding bacterial infections. GluMPA seems to have a toxic effect on thrombopoiesis.

LC-MS/MS improves screening towards 21-hydroxylase deficiency.

Basal serum 17OHP measurement remains the first screening step for nonclassic congenital adrenal hyperplasia (NCCAH) and the accuracy of the test is of high value. The aim of this study was to compare the accuracy of immunoassays to LC-MS/MS in the assessment of serum 17OHP and androgens concentration in women with hyperandrogenism and controls. 17OHP, total testosterone, androstendione and DHEA-S were measured in 39 women with clinically and/or biochemically evident hyperandrogenism and in 29 age-matched controls without clinical hyperandrogenism. 17OHP and androgens were measured by immunoassays and by LC-MS/MS. In patients group median 17OHP level measured by immunoassays was significantly higher compared to LC-MS/MS (5.49 nmol/l-ELISA NovaTec® and 3.57 nmol/l-ELISA DRG® versus 1.56 nmol/l-LC-MS/MS p < 0.0001) as well as in the control group (2.58 nmol/l-ELISA DRG® versus 1.14 nmol/l-LC-MS/MS p < 0.0001). Additional, unnecessary diagnostic procedures explaining elevated 17OHP level were undertaken in 85% of patients when NovaTec® test was used, in 50% when ELISA DRG® and in none when LC-MS/MS method was applied. Total testosterone, androstendione and DHEA-S concentrations in the patients and the controls assessed by the immunoassays were also significantly higher compared to LC-MS/MS. LC-MS/MS is more reliable diagnostic tool in the measurement of serum 17OHP and androgens concentrations compared to immunoassays in women with hyperandrogenism.

Trimethylamine-N-oxide: a carnitine-derived metabolite that prolongs the hypertensive effect of angiotensin II in rats.

BACKGROUND: Recent evidence suggests that an elevated plasma trimethylamine N-oxide (TMAO) level is associated with an increased risk of adverse cardiovascular events in humans; however, the mechanism is not clear. The aims of this study were to establish the plasma TMAO level in rats and to evaluate the effect of TMAO on arterial blood pressure (BP) and the hemodynamic effects of angiotensin II (Ang II). METHODS: Twelve-week-old, Sprague-Dawley rats were implanted with telemetric transmitters, and continuous recordings of heart rate, systolic BP (SBP), and diastolic BP (DBP) were made for 7 days before and 14 days during osmotic minipump-driven subcutaneous infusion of saline (controls), TMAO, low-dose Ang II, or Ang II + TMAO. Plasma TMAO concentration was evaluated using liquid chromatography coupled with triple-quadrupole mass spectrometry. RESULTS: The plasma TMAO concentration in controls was 0.57 µmol/L, whereas in TMAO-infused rats it was 58 µmol/L. Neither saline nor TMAO infusion affected SBP and DBP. Infusion of Ang II significantly increased SBP and DBP for the first 5 days of infusion only. In contrast, infusion of Ang II + TMAO produced a hypertensive response that lasted until the end of the experiment. TMAO infusions did not affect body weight and motor activity. CONCLUSIONS: We showed that physiological plasma TMAO concentration in rats was approximately 10 times lower than that reported in humans. Furthermore, the new finding of the study is that TMAO does not affect BP in normotensive animals. However, it prolongs the hypertensive effect of Ang II.