Aspirin suppresses TNF-α-induced MMP-9 expression via NF-κB and MAPK signaling pathways in RAW264.7 cells.

Numerous studies have indicated that the expression of matrix metalloproteinase-9 (MMP-9) contributes to the atherosclerotic plaque hemorrhage and rupture. Aspirin, a non-steroidal anti-inflammation drug, has been known for its anti-platelet effect in the prevention of the vascular complications of atherosclerosis. The present study aimed to investigate the pharmacological effects of aspirin on tumor necrosis factor-α (TNF-α)-induced MMP-9 expression and the underlying molecular mechanisms in murine macrophage RAW264.7 cells. Western blot analysis indicated that the protein level of MMP-9 was reduced by aspirin in a dose-dependent manner. In addition, downregulation of MMP-9 mRNA and activity were detected in aspirin-treated cells using quantitative polymerase chain reaction and a gelatin zymography assay separately. It was also observed that aspirin has a suppressive effect on the activation of nuclear factor (NF)-κB and inhibits the phosphorylation of mitogen-activated protein kinases (MAPKs), including extracellular signal-regulated kinases 1/2, p38 and c-Jun N-terminal kinase. Furthermore, subsequent to inhibition of the MAPK pathway by specific inhibitors (PD98059, SB203580 and SP600125), the expression of MMP-9 was reduced, indicating that the inhibitory effect of aspirin on MMP-9 in TNF-α-treated RAW264.7 cells may be, at least in part, through suppression of NF-κB activation and the MAPK pathway. These findings support the notion that aspirin has therapeutic potential application in the prevention and treatment of atherosclerosis disease.

Comparison of tranexamic acid pharmacokinetics after intra-articular and intravenous administration in rabbits.

Tranexamic Acid (TXA) is commonly administered in total knee arthroplasty for reducing blood loss. There has been a growing interest in the topical use of TXA except intravenous use for prevention of bleeding in TKA. The aim of this study was to develop and validate a HPLC-MS method to detect TXA and apply to compare the pharmacokinetic profile of TXA after intravenous (IV) and topical intra-articular (IA) application of TXA at a dose of 20 mg/kg in rabbits. In order to prove intra-articular administration is better than that of intravenous administration from the point of rabbit pharmacokinetic. Two groups of rabbits (n=6/group) respectively received TXA intra-articularly or intravenously. Blood samples were collected at scheduled time. The concentration of TXA in plasma was determined by a validated HPLC-MS method. Excellent linearity was found between 0.015 and 70.0µg/ml with a lower limit of quantitation (LLOQ) of 0.015µg/ml (r>0.99); moreover, all the validation data including accuracy and precision (intra- and inter-day) were all within the required limits. The pharmacokinetic parameters in IA and IV group were: Cmax: 30.65±3.31 VS 54.05± 6.21µg/ml (p<0.01); t1/2: 1.26±0.05 VS 0.68±0.13h (p<0.05); AUC0-t: 42.98±7.73 VS 23.39±4.14µg/ml• h (p<0.01), time above the minimum effective concentration (%T > MEC): 1.5-2.2 VS 0.7-1.2h (p<0.05). HPLC-MS method is suitable for TXA pharmacokinetic studies. The results demonstrated that topical intra-articular application of TXA showed a reduced peak plasma concentration and prolonged therapeutic drug level compared with intravenous TXA from the point of rabbit pharmacokinetic.

Genetic polymorphisms of CYP2C19 2 and ABCB1 C3435T affect the pharmacokinetic and pharmacodynamic responses to clopidogrel in 401 patients with acute coronary syndrome.

BACKGROUNDS AND OBJECTIVES: Clopidogrel, an inhibitor of platelet ADP P2Y12 receptors, plays an important role in the prevention of stent thrombosis. However, some patients do not attain adequate antiplatelet effects. Studies have shown that the genetic variation in CYP2C19*2 is associated with an impaired response to clopidogrel. This study was designed to investigate the genetic variants of 21 genes involving in the absorption, metabolism, and pharmacodynamics of clopidogrel. The effects of these genes on the plasma level of clopidogrel and its metabolites (active clopi-H4 and inactive CLPM) and platelet reactivity were also studied. METHODS AND RESULTS: 401 acute coronary syndrome (ACS) patients received either a 300 mg loading dose following 75 mg maintenance dose daily or a 75mg maintenance dose daily of clopidogrel. The inhibition of platelets was assessed using light transmittance aggregometry. Plasma concentrations of clopidogrel as well as its active (clopi-H4) and inactive (CLPM) metabolites were measured using HPLC-MS-MS method. Among 21 genes, the carriers of CYP2C19*2 were associated with lower exposure to its active (clopi-H4) and inactive (CLPM) metabolites (both P<0.05 vs. non-carriers) and thus decreased platelet inhibition (P<0.05 vs. non-carriers). Notably, the carriers of ABCB1 C3435T were associated with lower levels of plasma clopidogrel and its active (clopi-H4) and inactive (CLPM) metabolites (all P<0.05 vs. non-carriers) which also correlated with subsequently decreased platelet inhibition (P<0.05 vs. non-carriers). There were no obvious effects of other studied genes on clopidogrel. CONCLUSIONS: CYP2C19*2 is a determinant for the formation of the active metabolite of clopidogrel and its antiplatelet effects. Meanwhile, ABCB1 C3435T plays an important role in intestinal absorption of clopidogrel which further affects the exposure to the active metabolite of clopidogrel and platelet aggregation.

Bioequivalence evaluation of two formulations of pidotimod using a limited sampling strategy.

The aim of this study was to develop a limited sampling strategy (LSS) to assess the bioequivalence of two formulations of pidotimod. A randomized, two-way, cross-over study was conducted in healthy Chinese volunteers to compare two formulations of pidotimod. A limited sampling model was established using regression models to estimate the pharmacokinetic parameters and assess the bioequivalence of pidotimod. The model was internally validated by the Jack-knife method and graphical methods. The traditional non-compartmental method was also used to analyze the data and compared with LSS method. The results indicate that following oral administration of a single 800 mg dose, the plasma AUC(0-12 h) and C(max) of pidotimod can be predicted accurately using only two to four plasma samples. The bioequivalence assessment based on the LSS models provided results very similar to that obtained using all the observed concentration-time data points and indicate that the two pidotimod formulations were bioequivalent. A LSS method for assessing the bioequivalence of pidotimod formulations was established and proved to be applicable and accurate. This LSS method could be considered appropriate for a pidotimod bioequivalence study, providing an inexpensive cost of sampling acquisition and analysis. And the methodology presented here may also be applicable to bioequivalence evaluation of other medications.