Objective-To test the hypothesis that chronic infusion of angiotensin-(1-7) [Ang-(1-7)] may dose-dependently inhibit atherosclerotic lesion formation by targeting vascular smooth muscle cells and a large dose of Ang-(1-7) may stabilize mature plaque by targeting macrophages. Approach and Results-In vivo, the effects of Ang-(1-7) on atherogenesis and plaque stability were observed in ApoE −/− mice fed a high-fat diet and chronic angiotensin II infusion. In vitro, the effects of Ang-(1-7) on vascular smooth muscle cells' proliferation and migration, and macrophage inflammatory cytokines were examined. Ang-(1-7) dosedependently attenuated early atherosclerotic lesions and inhibited vascular smooth muscle cells' proliferation and migration via suppressing extracellular regulated protein kinase/P38 mitogen-activated protein kinase and janus kinase/ signal transducers and activators of transcription activities and enhancing smooth muscle 22α and angiotensin II type 2 receptor expression. Ang-(1-7) treatment resulted in high contents of collagen and vascular smooth muscle cells, and low contents of macrophages and lipids in carotid mature plaques. Ang-(1-7) lowered the expression levels of proinflammatory cytokines and activities of matrix metalloproteinases in mature plaques. Conclusions-Ang-(1-7) treatment inhibits early atherosclerotic lesions and increases plaque stability in ApoE−/− mice, thus providing a novel and promising approach to the treatment of atherosclerosis. Materials and MethodsMaterials and Methods are available in the online-only Supplement. Results Body Weight, Blood Pressure, and Serum Lipid ProfileAt the end of the first part (8 weeks) and the second part (10 weeks) of the in vivo study, both systolic and diastolic blood pressures were substantially increased in comparison with the baseline blood pressure measurements (data not shown). However, no significant differences were found in body weight, blood pressure, and serum lipid levels among vehicle-treated, Ang-(1-7)-treated and Ang-(1-7)+A779-treated groups, indicating that chronic infusion of Ang-(1-7) or A779 had no significant effects on these parameters (Table I in the online-only Data Supplement). In ApoE −/− mice without Ang-II infusion, blood pressure levels were not statistically different among vehicle-treated, Ang-(1-7)-treated, and Ang-(1-7)+A779-treated groups ( Figure 1; Table II in the online-only Data Supplement). Aortic Lesion FormationIn the first part of the in vivo study, the relative en face lesion area of the aorta arches was dose-dependently decreased in the Ang-(1-7)-treated subgroups. However, only the difference between the large dose of Ang-(1-7) subgroup and the vehicle-treated group reached a statistical significance. The antiatherosclerosis effect of Ang-(1-7) was significantly reversed by coadministration of A779 (Figure 2A and 2B). Similarly, the relative cross-sectional area of the aortic lesion also showed a dose-dependent decrease in the Ang-(1-7)-treated subgroups but only the difference between the large do...

ABSTRACT:Luteolin is mainly metabolized by phase II enzymes in animals and humans with glucuronidation and sulfation as the two known metabolic pathways. Although methylation of luteolin was reported previously, the structure of the methylated metabolites and the enzymes involved in the process have not been clarified. In our study, two methylated metabolites, M1 (chrysoeriol) and M2 (diosmetin), were identified in the urine after intravenous administration of luteolin to rats, and the data suggested that the methylation was mediated by catechol-O-methyltransferase (COMT). When luteolin was coadministered with a specific COMT inhibitor, entacapone, the formation of M1 and M2 was significantly reduced, whereas the plasma concentration of luteolin increased. Methylation of luteolin was also studied in vitro using rat tissue homogenates. The apparent kinetic parameters associated with the formation of M1 and M2 in vitro were estimated, and regioselectivity of methylation of luteolin was observed. In the in vitro experiment, there was a preference for the formation of M2 over M1. In contrast, accumulation of M1 was preferred in vivo in both rat plasma and urine after an intravenous dose of luteolin. In conclusion, COMT played a crucial role in the disposition of luteolin in rats. Our results indicated that the methylation pathway in rats was significantly reduced when luteolin was coadministered with a specific COMT inhibitor. Therefore, COMT-associated drug-drug interactions need be considered in the future in luteolin clinical trials because the plasma concentrations and related therapeutic effects may be altered in vivo in the presence of a COMT inhibitor.

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ABSTRACT:para-Aminosalicylic acid (PAS; 4-amino-2-hydroxybenzoic acid), an antituberculosis drug in use since the 1950s, has recently been suggested to be an effective agent for treatment of manganeseinduced parkinsonian disorders. However, the neuropharmacokinetics of PAS and its metabolite N-acetyl-para-aminosalicylic acid (AcPAS; N-acetyl-4-amino-2-hydroxybenzoic acid) are unknown. This study was designed to investigate the pharmacokinetics of PAS and its distribution in brain to help better design the dosing regimen for clinical trials. Male Sprague-Dawley rats received single femoral artery injections of PAS (200 mg/kg). Plasma, cerebrospinal fluid, and brain tissues were collected, and PAS and AcPAS concentrations were quantified by high-performance liquid chromatography. After administration, the concentrations of PAS declined rapidly in plasma with an elimination t 1/2 of 34 min; the metabolite AcPAS was detected in plasma and eliminated with a t 1/2 of 147 min. PAS and AcPAS were detected in brain tissues; AcPAS had a much higher tissue concentration and a longer t 1/2 than the parent PAS in most tissues examined. Although both were present in blood or tissues as free, unbound molecules, AcPAS appeared to have a higher tissue affinity than PAS. Taken together, our results suggest that a dosing regimen with continuous intravenous infusion of PAS is necessary to achieve therapeutic levels in targeted brain regions. Furthermore, PAS and AcPAS seem to be effective in reducing manganese levels in brain.

Post-translational modifications (PTMs) of therapeutic monoclonal antibodies (mAbs) are important product quality attributes (PQAs) that can potentially impact drug stability, safety, and efficacy. The PTMs of a mAb may change remarkably in the bloodstream after drug administration compared to in vitro conditions. Thus, monitoring in vivo PTM changes of mAbs helps evaluate the criticality of PQAs during the product risk assessment. In addition, quantitation of the subject exposures to PTM variants helps assess the impact of PTMs on the safety and efficacy of therapeutic mAbs. Here, we developed an immunocapture-liquid chromatography/mass spectrometry (LC/MS) method to quantify in vivo PTM changes a therapeutic mAb overtime in single- and multiple-dose monkey pharmacokinetic (PK) studies. We also built mathematical models to predict the in vivo serum concentrations of PQAs, the subject exposures to PQAs, and the relative abundance of PQAs in single- and multiple-dose regimens. The model predictions are in good agreement with the experimental results. The immunocapture-LC/MS method and mathematical models enable bioanalytical chemists to quantitatively assess the criticality of PQAs during drug development.