Phototoxic risk assessment of dermally-applied chemicals with structural variety based on photoreactivity and skin deposition.

Combined use of photochemical and pharmacokinetic (PK) data for phototoxic risk assessment was previously proposed, and the system provided reliable phototoxic risk predictions of chemicals in same chemical series. This study aimed to verify the feasibility of the screening system for phototoxic risk assessment on dermally-applied chemicals with wide structural diversity, as a first attempt. Photochemical properties of test chemicals, 2-acetonaphthalene, 4'-methylbenzylidene camphor, 6-methylcoumarin, methyl N-methylanthranilate, and sulisobenzone, were evaluated in terms of UV absorption and reactive oxygen species (ROS) generation, and PK profiles of the test chemicals in rat skin were characterized after dermal co-application. All test chemicals showed strong UVA/B absorption with molar extinction coefficients of over 3000 M-1⋅cm-1, and irradiated 2-acetonaphthalene, 6-methylcoumarin, and methyl N-methylanthranilate exhibited significant ROS generation. Dermally-applied 2-acetonaphthalene and 4'-methylbenzylidene camphor indicated high and long-lasting skin deposition compared with the other test chemicals. Based on the photochemical and PK data, 2-acetonaphthalene was predicted to have potent phototoxic risk. The predicted phototoxic risk of the test chemicals by integration of obtained data was mostly consistent with their in vivo phototoxicity observed in rat skin. The screening strategy employing photochemical and PK data would have high prediction capacity and wide applicability for photosafety evaluation of chemicals.

Chaihu-Shugan-San and absorbed meranzin hydrate induce anti-atherosclerosis and behavioral improvements in high-fat diet ApoE-/- mice via anti-inflammatory and BDNF-TrkB pathway.

The comorbidity of coronary heart disease (CHD) and depression in patients is extremely prevalent, with a rate from 20 to 50%, while depression-like behaviors exist in a larger percentage of patients. Therefore, the study of comorbidities is particularly urgent. Chaihu-Shugan-San (CSS), a classical traditional Chinese medicine formula, has been used to treat CHD with depression for hundreds of years. However, the mechanism of its action on comorbidities remains unclear. Here, we focused on the behavioral changes in ApoE-/- mice fed a high-fat diet (HFD) and elucidated the mechanism of CSS and its main absorbed component, meranzin hydrate (MH), as an anti-atherosclerosis and anti-depression agent. In the present study, mice were fed an HFD for 16 weeks and were intragastrically administered high and low doses of CSS and MH. Depressive-like behaviors were evaluated by the sucrose preference test, the open-field test, the light-dark test and the tail-suspension test, after which atherosclerotic plaques, plasma lipids, inflammatory cytokine levels and the expression of BDNF/TrkB were measured. We demonstrated that the atherosclerosis model group exhibited significant depressant behaviors. Moreover, CSS inhibited depressive-like behavioral changes, reduced atherosclerotic plaque areas, plasma total cholesterol, triglycerides, LDL-cholesterol levels and inflammatory cytokines including TNF-α, IL-1ß, and IL-6 in plasma and hippocampi, increased the protein and mRNA expression of BDNF and TrkB in the aorta and the hippocampus. Interestingly, MH, the main component in CSS that is absorbed in the plasma and hippocampus, exerted effects similar to those of CSS. In addition, MH increased the protein and mRNA expression of BDNF and TrkB in human umbilical vein endothelial cells (HUVECs) induced by LPS. Collectively, these results suggest that MH represents the CSS decoction, induces anti-atherosclerosis effects and improves depression-like behaviors in HFD-fed ApoE-/- mice. Moreover, the regulation of proinflammatory factors and BDNF-TrkB signaling are possibly involved in this process. Our findings indicate that MH is a potential phytochemical compound for the prevention of the comorbidity of atherosclerosis and depression.

In vitro and in vivo assessment of the effect of antiprotozoal compounds isolated from Psoralea corylifolia against Ichthyophthirius multifiliis in fish.

Ichthyophthirius multifiliis, an external fish parasite, often causes significant economic damage to the aquaculture industry. Since the use of malachite green was banned, the search of alternative substance to control I. multifiliis infections becomes stringent. In present study, in vitro and in vivo anti-ich efficacies of isopsoralen and psoralidin, two active compounds isolated from methanol extract of Psoralea corylifolia by bioassay-guided fractionation based on the efficacy of anti-ich encysted tomonts, were evaluated. In vitro antiprotozoal efficacy of psoralidin is much better than that of isopsoralen. Psoralidin can kill all theronts at concentrations of 0.8 mg/L or more during 4 h exposure; and terminate reproduction of I. multifiliis post 6 h exposure of protomonts to 0.9 mg/L and encysted tomonts to 1.2 mg/L. In vivo trials showed that 5 h exposure of infected fish to 2.5 mg/L of psoralidin significantly reduced the number of theronts released from tomonts. Furthermore, we observed that a part of protomonts, collected from infected fish post treatment, presented characteristic morphological changes of apoptosis after staining with Annexin V-EGFP/propidium iodide, indicating the possible mechanism of psoralidin against I. multifiliis trophont in situ. On the basis of these results, psoralidin can be used as a potential lead compound for the development of commercial drug against I. multifiliis.

Economic evaluation of a pharmacogenetic dosing algorithm for coumarin anticoagulants in The Netherlands.

AIM: To investigate the cost-effectiveness of a pharmacogenetic dosing algorithm versus a clinical dosing algorithm for coumarin anticoagulants in The Netherlands. MATERIALS & METHODS: A decision-analytic Markov model was used to analyze the cost-effectiveness of pharmacogenetic dosing of phenprocoumon and acenocoumarol versus clinical dosing. RESULTS: Pharmacogenetic dosing increased costs by €33 and quality-adjusted life-years (QALYs) by 0.001. The incremental cost-effectiveness ratios were €28,349 and €24,427 per QALY gained for phenprocoumon and acenocoumarol, respectively. At a willingness-to-pay threshold of €20,000 per QALY, the pharmacogenetic dosing algorithm was not likely to be cost effective compared with the clinical dosing algorithm. CONCLUSION: Pharmacogenetic dosing improves health only slightly when compared with clinical dosing. However, availability of low-cost genotyping would make it a cost-effective option.

A microfluidic approach for in vitro assessment of interorgan interactions in drug metabolism using intestinal and liver slices.

Over the past two decades, it has become increasingly clear that the intestine, in addition to the liver, plays an important role in the metabolism of xenobiotics. Previously, we developed a microfluidic-based in vitro system for the perifusion of precision-cut liver slices for metabolism studies. In the present study, the applicability of this system for the perifusion of precision-cut intestinal slices, and for the sequential perifusion of intestinal and liver slices, all from rat, was tested to mimic the in vivo first pass situation. Intestinal and liver slices, exposed to the substrates 7-ethoxycoumarin (7-EC), 7-hydroxycoumarin (7-HC) and lidocaine (Li), exhibited similar metabolic rates in the biochip and in the well plates for periods of at least 3 h. The metabolic rate remained the same when two slices were placed in adjacent microchambers and perifused sequentially. In addition, the system has been adapted to sequentially perifuse intestinal and liver tissue slices in a two-compartment co-culture perfusion system with a continuous flow of medium. It becomes possible to direct metabolites or other excreted compounds formed by an intestinal slice in the first compartment to the second compartment containing a liver slice. The intestine does not influence liver metabolism for these substrates. The interplay between these two organs was demonstrated by exposing the slices to the primary bile acid, chenodeoxycholic acid (CDCA). CDCA induced the expression of fibroblast growth factor 15 (FGF15) in the intestinal slice, which resulted in a stronger down-regulation of the enzyme, cytochrome P450 7A1 (CYP7A1), in the liver slice in the second compartment than when the liver slice was exposed to CDCA in a single-microchamber biochip. We thus demonstrate in this paper that intestinal slices, in addition to liver slices, remain functional in the biochip under flow conditions, and that the two-microchamber biochip has great potential for the study of interorgan effects. This is the first example of the incorporation of both liver and intestinal slices in a microfluidic device. Use of this microfluidic system will improve our insight into interorgan interactions and elucidate as yet unknown mechanisms involved in toxicity, gene regulation and drug-drug interactions.

A systematic review of cost-effectiveness analyses of pharmacogenetic-guided dosing in treatment with coumarin derivatives.

Anticoagulant therapy with coumarin derivatives is often sub- or supra-therapeutic, resulting in an increased risk of thromboembolic events or hemorrhage, respectively. Pharmacogenetic-guided dosing has been proposed as an effective way of reducing bleeding rates. Clinical trials to confirm the safety, efficacy and effectiveness of this strategy are ongoing, but in addition, it is also necessary to consider the cost-effectiveness of this strategy. This article describes the findings of a systematic review of published cost-effectiveness analyses of pharmacogenetic-guided dosing of coumarin derivatives. Similarities and differences in the approaches used were examined and the quality of the analyses was assessed. The results of the analyses are not sufficient to determine whether or not pharmacogenetic-guided dosing of coumarins is cost effective. More reliable cost-effectiveness estimates need to become available before it is possible to recommend whether or not this strategy should be applied in clinical practice.

Management of coumarin-associated coagulopathy in the non-bleeding patient: a systematic review.

BACKGROUND AND OBJECTIVES: Excessive anticoagulation is a frequent complication of anticoagulant therapy. The risk of hemorrhage approximately doubles for each one point increase in the International Normalized Ratio (INR) above 3.0. Reducing a prolonged INR to within the desired therapeutic range requires that oral anticoagulants be withheld. In addition, vitamin K may be administered. Since this latter treatment can produce rapid reductions in the INR, it must be carefully tailored to meet individual needs, balancing the risk of bleeding against the potential risk of causing thromboembolism. METHODS: To review available literature on the management of coumarin-associated coagulopathy in asymptomatic patients, a Medline search was carried out and papers published in English from 1966 and 2003 were identified. All available information on the management of asymptomatic patients presenting with coumarin-associated coagulopathy was analyzed. RESULTS: Following the results of clinical studies that only used an elevated INR as a surrogate end-point for the risk of bleeding, low dose oral vitamin K appears as the preferable strategy for rapidly restoring therapeutic INR levels in asymptomatic patients who present with an excessively prolonged INR due to warfarin therapy. For the treatment of patients with asymptomatic acenocoumarol-induced coagulopathy, vitamin K does not add any benefit to the strategy of simply withholding oral anticoagulant treatment. INTERPRETATION AND CONCLUSIONS: Large randomized trials using clinical end-points are now required to provide evidence-based treatment recommendations for patients with coumarin-associated coagulopathy.