Biochemical phenotype and its relationship to treatment in 16 individuals with PCCB c.1606A > G (p.Asn536Asp) variant propionic acidemia.

Propionic acidemia (PA) is caused by inherited deficiency of mitochondrial propionyl-CoA carboxylase (PCC) and results in significant neurodevelopmental and cardiac morbidity. However, relationships among therapeutic intervention, biochemical markers, and disease progression are poorly understood. Sixteen individuals homozygous for PCCB c.1606A > G (p.Asn536Asp) variant PA participated in a two-week suspension of therapy. Standard metabolic markers (plasma amino acids, blood spot methylcitrate, plasma/urine acylcarnitines, urine organic acids) were obtained before and after stopping treatment. These same markers were obtained in sixteen unaffected siblings. Echocardiography and electrocardiography were obtained from all subjects. We characterized the baseline biochemical phenotype of untreated PCCB c.1606A > G homozygotes and impact of treatment on PCC deficiency biomarkers. Therapeutic regimens varied widely. Suspension of therapy did not significantly alter branched chain amino acid levels, their alpha-ketoacid derivatives, or urine ketones. Carnitine supplementation significantly increased urine propionylcarnitine and its ratio to total carnitine. Methylcitrate blood spot and urine levels did not correlate with other biochemical measures or cardiac outcomes. Treatment of PCCB c.1606A > G homozygotes with protein restriction, prescription formula, and/or various dietary supplements has a limited effect on core biomarkers of PCC deficiency. These patients require further longitudinal study with standardized approaches to better understand the relationship between biomarkers and disease burden.

Vitamin C intervention may lower the levels of persistent organic pollutants in blood of healthy women - A pilot study.

Emerging evidence suggests that exposure to endocrine-disrupting chemicals including persistent organic pollutants (POPs) such as organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs) has a long term impact on human health. The goal of this pilot study was to test whether antioxidant intervention by vitamin C supplementation may be a remedial approach to decrease body burden of POPs in humans. Using solid phase extraction coupled with a triple quadrupole mass spectrometer and a gas chromatography high resolution mass spectrometry, we measured 18 PCBs, 7 OCPs, and 5 PBDEs in the blood of 15 healthy California women (8 were obese/overweight and 7 had normal weight) before and after 2 months of vitamin C supplementation (1000 mg/day). We observed higher PBDE levels than PCBs and OCPs, but only PCB and OCP levels were strongly and positively correlated with participant's BMI and age. We also found statistically significant decreases in 6 PCBs (PCB-74, PCB-118, PCB-138, PCB-153, PCB-180, and PCB-187), and 2 OCPs (4,4'-DDE, and 4,4'-DDT), but not PBDEs after vitamin C supplementation. Pending confirmation of this pilot finding in a larger study of both sexes, vitamin C intervention may have important public health implications in protecting health by reducing body burdens of POPs.

Ultra-performance liquid chromatography tandem mass spectrometry combined with automated MetaboLynx analysis approach to screen the bioactive components and their metabolites in Wen-Xin-Formula.

Wen-Xin-Formula (WXF), a famous traditional prescription, has been widely used to treat myocardial ischemia syndrome for thousands of years. However, the constituents absorbed into blood after oral administration of WXF remain unknown. Here, an integrative ultra performance liquid chromatography coupled with electrospray ionization/quadrupole-time-of-flight mass spectrometry (UPLC-ESI-Q-TOF-MS) combined with the MetaboLynx approach was established to investigate the absorbed constituents in rats after oral administration of WXF. A hyphenated electrospray ionization and quadrupole-time-of-flight analyzer was used for the determination of accurate mass of the molecule and fragment ions. With this rapid and automated analysis method, a total of 32 peaks were tentatively characterized in vivo based on MS and MS/MS data and comparison with available databasess, 26 of which were parent components and six metabolites. These components mainly were ginsenosides, paeoniflorin, galloyl glucose, berberis alkaloids, phenolic, phenolic glycosides and unsaturated fatty acids, glucuronide products of original berberis alkaloids. The present study demonstrates that integrative UPLC-ESI-Q-TOF-MS technique and MetaboLynx data processing method were successfully applied for the rapid discovery of potentially bioactive components and metabolites from WXF, and proved that the established method could help to explore the effective substances for further research into WXF.

Matrix-assisted laser desorption/ionization for simultaneous quantitation of (acyl-)carnitines and organic acids in dried blood spots.

RATIONALE: Screening for inborn errors of metabolism using mass spectrometry is part of nationwide newborn screening programs and involves the detection of disease relevant (acyl-)carnitines and organic acids from dried blood spots. Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry (MALDI-MS) is a well-established tool for proteomics approaches. In recent years, this technique has become more and more integrated in analysis and identification of small metabolites and disease biomarkers in daily clinical laboratories. METHODS: We used a combination of both MALDI and high-resolution accurate mass (HR/AM) mass spectrometry using a linear ion trap-Orbitrap for the identification of small molecules from dried blood spots that serve as biomarkers for inborn errors of metabolism. The levels of detected metabolite species were compared between healthy newborns and affected patients with various inborn errors of metabolism using isotopically labeled internal standards and new bioinformatics software, respectively. RESULTS: (Acyl-)carnitine levels from normal and affected patients could be quantified and differentiated. Additionally, using the high resolving power of full scan Orbitrap mass spectrometry and novel software tools we demonstrated the identification and quantification of disease-specific organic acids. CONCLUSIONS: MALDI-HR/AM and full scan spectra to obtain information for the metabolic status of patients is a promising complementary approach to electrospray ionization mass spectrometry by simplified sample preparation, facilitating the screening of hundreds of metabolites from small sample volumes.

QTc shortening with a new investigational cancer drug: a brief case study.

INTRODUCTION: BAY-79 is an inhibitor of receptor tyrosine kinases with high selectivity versus other kinases. Species scaling, complicated by nonlinear pharmacokinetics, predicted a C(max.u) of 36-178nmol/L at the human efficacious exposure. METHODS: Preclinical cardiovascular safety pharmacology studies assessed currents (hERG, I(Na)), action potential (AP, rabbit Purkinje fiber), hemodynamic/ECG parameters (anesthetized Beagle dogs, intravenous infusion), and proarrhythmic potential (rabbit Langendorff heart Screenit model). RESULTS: Both hERG K(+) current and hNav1.5 Na(+) current were inhibited with low potency (IC(20)>10micromol/L). Purkinje fiber APs remained unaffected at 10micromol/L, but at 100micromol/L displayed reverse use-dependent AP duration shortening (APD(90)-33% at 1Hz) and triangulation. Infusion of BAY-79 into anesthetized dogs was associated with moderate hemodynamic effects (increased heart rate and diastolic blood pressure, reduced stroke volume) and marked QTcV shortening (-25ms) starting at approximately 0.65micromol/L (unbound); QRS was not changed. Assessment of the proarrhythmic potential in the Screenit model showed effects (AP duration shortening, triangulation, instability, reduced coronary flow, slowed conduction) at > or =30micromol/L (0.5h/concentration) and at 3micromol/L with longer exposure (2.5h/concentration). DISCUSSION: BAY-79 at plasma concentrations slightly higher than those predicted to be therapeutically efficacious in humans is associated with QTc shortening in dogs but of unclear mechanistic basis. The QTc shortening associated proarrhythmic potential of BAY-79 together with other considerations finally resulted in an unfavorable risk-benefit assessment.

A phase I and pharmacokinetic study of the selective, non-peptidic inhibitor of matrix metalloproteinase BAY 12-9566 in combination with etoposide and carboplatin.

Matrix metalloproteinases (MMPs) are zinc-dependent endopeptidases that degrade the extracellular matrix during the processes of invasion, metastasis and angiogenesis. BAY 12-9566 (BAY) is a selective, non-peptidic biphenyl inhibitor of MMPs, with nanomolar inhibitory activity against MMP-2, -3 and -9, and anti-invasive, anti-metastatic and anti-angiogenic activity in a variety of tumor models. This phase I study of oral BAY was conducted to evaluate the safety and pharmacokinetics of BAY when administered in combination with etoposide (VP-16) or in combination with VP-16 and carboplatin (CBDCA) in subjects with advanced cancer. The first cohort of patients (n=8) received a cycle of VP-16, 60 mg/m, followed 1 week later by a fixed daily oral dose of BAY, 800 mg b.i.d., to which three potential possible doses of VP-16 (low dose: 60 mg/m; mid dose: 90 mg/m; high dose: 120 mg/m) were added every 3 weeks as tolerated. The second cohort (n=5) received VP-16 (120 mg/m) and CBDCA (AUC=5) followed 1 week later by a fixed daily oral dose of BAY (800 mg) b.i.d., to which VP-16 (120 mg/m) and CBDCA (AUC=5) were added. Dose-limiting toxicity (DLT) was defined as toxicity grade 3 or above. Maximum tolerated dose was declared if two or more patients experienced DLT. A performance status of 0-2 and acceptable organ function were required for eligibility. Plasma concentrations of BAY and VP-16 were measured to investigate pharmacokinetic interactions. Eight eligible patients with a variety of tumor types (median age 64 years, range 44-76) were enrolled in the first cohort, six of who whom completed all three levels of VP-16. Progressive disease occurred in five of the eight patients; three patients continued on study with treatment. Drug level and pharmacokinetics analysis of BAY and VP-16 were also determined. The combination of BAY and VP-16 was tolerable in the first cohort, permitting enrollment of the second cohort. In the second cohort (n=5), the combination of BAY, VP-16 and CDBCA was intolerable at the doses used due to excessive hematologic toxicity in the first five patients enrolled. Pharmacokinetics and toxicity analysis was performed for this group of patients. Only Level 1 of treatment was completed for Cohort II. At this point the study was halted due to toxicity and the results of an interim analysis that failed to demonstrate sufficient clinical activity of this compound in other clinical trials. We conclude that the combination of BAY and VP-16 was well tolerated. However, the combination of BAY, VP-16 and CDBCA produces significant hematologic toxicity. Findings from this study may help to direct further studies with other inhibitors of MMPs.