Chronopharmacological study of interferon-a in mice

ABSTRACT The influence of dosing time on the pharmacological effects (fever and antiviral activity) and the pharmacokinetics of interferon-␣ (IFN-␣) was investigated in ICR male mice under lightdark (12:12) cycle. There was a significant circadian rhythm in rectal temperature, as an index of fever, at 0.5 hr after IFN-␣ (10.0 MIU/kg i.v.) injection. The rhythmic pattern resembled overall the rhythm that occurs in the nondrugged state. However, the percent change from basal level of rectal temperature varied according to the dosing time. The rhythmicity corresponded to the dosing time-dependent difference of PGE 2 levels in thalamus after IFN-␣ injection, but it did not correspond to that of plasma IFN-␣ concentrations. A significant dosing time-dependent difference was also demonstrated for 2Ј-5Јoligoadenylate synthetase activities, as an index of antiviral activity, in plasma and liver at 24 hr after IFN-␣ injection. It was related to the rhythmicity in plasma IFN-␣ concentrations that was caused by the rhythmicity in clearance of IFN-␣. The choice of the most appropriate time of day for drug administration may help to achieve rational chronotherapeutics of IFN-␣ in certain experimental and clinical situations. A large number of physiological rhythmic variables are demonstrated in the CNS, in hormone secretion and so on Interferons, which belong to a group of cytokines, have been widely used as antiviral and antitumor agents in the human. However, interferons cause unavoidable adverse effects such as fever, fatigue, headache, rigors and myalgias. In particular, fever is an indispensable side effect in nearly all patients during the early phase of interferon treatment. Administration of IFN-␣ in cancer patients is better tolerated in evening than in morning Rectal temperature and immune functions show significant circadian rhythms in mammals under both nondrugged and drugged conditions The purpose of this study was to examine the diurnal change of IFN-␣ induced fever and antiviral activity in mice. The mechanisms underlying these phenomena were also investigated from the perspective of IFN-␣ pharmacokinetics. Methods Animals and treatments. Male ICR mice (5 weeks old) were purchased from Charles River Japan Inc. (Kanagawa, Japan). Mice were housed 6 or 10 per cage in a light-controlled room (light on from 07:00 to 19:00) at a room temperature of 24°C Ϯ 1°C and a humidity of 60% Ϯ 10% with food and water ad libitum. All mice were adapted to their light-dark cycle for 2 weeks before the experiments. In order to study the fever induced by IFN-␣ (Sumiferon, Sumitomo Seiyaku Co., Osaka, Japan), groups of six mice injected i.v. with 1.0, 5.0 or 10.0 MIU/kg IFN-␣ or sterilized saline at the same circadian phase (09:00). IFN-␣ was diluted by sterilized saline to adjust the concentration to 0.2, 1.0 and 2.0 MIU/ml. The volume of injection was 0.05 ml/10.0 g b.wt. The drug solutions were used within 30 min after preparation in order not to decrease their biologic activity. Rectal temperature was continuously determined before, and at 0.5, 1.0, 2.0 and 4.0 hr after, IFN-␣ or saline injection. In the study of the circadian rhythms of IFN-␣-induced fever and plasma IFN-␣ concentrations, groups of 8 to 10 mice were injected i.v. with 10.0 MIU/kg IFN-␣ or saline at one of six times: 09:00, 13:00, 17:00, 21:00, 01:00 or 05:00. Rectal temperature was determined before, and at 0.5, 1.0, 1.5 and 2.0 hr after, IFN-␣ or saline injection. Percent change of rectal temperature (%) from basal level was calculated as follows: % ϭ ([rectal temperature after IFN-␣ injection Ϫ rectal IFN-␣ before Received for publication December 27, 1996. ABBREVIATIONS: IFN-␣, interferon-␣; 2Ј-5ЈOAS, 2Ј-5Јoligoadenylate synthetase; CL, clearance; V c , central volume of distribution; K 12 , distribution rate constant from central to peripheral compartment; K 21 , distribution rate constant from peripheral to central compartment

Molecular basis for the dosing time-dependency of anti-allodynic effects of gabapentin in a mouse model of neuropathic pain

<p>Abstract</p> <p>Background</p> <p>Neuropathic pain is characterized by hypersensitivity to innocuous stimuli (tactile allodynia) that is nearly always resistant to NSAIDs or even opioids. Gabapentin, a GABA analogue, was originally developed to treat epilepsy. Accumulating clinical evidence supports the effectiveness of this drug for diverse neuropathic pain. In this study, we showed that the anti-allodynic effect of gabapentin was changed by the circadian oscillation in the expression of its target molecule, the calcium channel α2δ-1 subunit.</p> <p>Results</p> <p>Mice were underwent partial sciatic nerve ligation (PSL) to create a model of neuropathic pain. The paw withdrawal threshold (PWT) in PSL mice significantly decreased and fluctuated with a period length about 24 h. The PWT in PSL mice was dose-dependently increased by intraperitoneal injection of gabapentin, but the anti-allodynic effects varied according to its dosing time. The protein levels of α2δ-1 subunit were up-regulated in the DRG of PSL mice, but the protein levels oscillated in a circadian time-dependent manner. The time-dependent oscillation of α2δ-1 subunit protein correlated with fluctuations in the maximal binding capacity of gabapentin. The anti-allodynic effect of gabapentin was attenuated at the times of the day when α2δ-1 subunit protein was abundant.</p> <p>Conclusions</p> <p>These findings suggest that the dosing time-dependent difference in the anti-allodynic effects of gabapentin is attributable to the circadian oscillation of α2δ-1 subunit expression in the DRG and indicate that the optimizing its dosing schedule helps to achieve rational pharmacotherapy for neuropathic pain.</p

Time-Dependent Interaction between Differentiated Embryo Chondrocyte-2 and CCAAT/Enhancer-Binding Protein ␣ Underlies the Circadian Expression of CYP2D6 in Serum- Shocked HepG2 Cells

ABSTRACT Differentiated embryo chondrocyte-2 (DEC2), also known as bHLHE41 or Sharp1, is a pleiotropic transcription repressor that controls the expression of genes involved in cellular differentiation, hypoxia responses, apoptosis, and circadian rhythm regulation. Although a previous study demonstrated that DEC2 participates in the circadian control of hepatic metabolism by regulating the expression of cytochrome P450, the molecular mechanism is not fully understood. We reported previously that brief exposure of HepG2 cells to 50% serum resulted in 24-h oscillation in the expression of CYP3A4 as well as circadian clock genes. In this study, we found that the expression of CYP2D6, a major drug-metabolizing enzyme in humans, also exhibited a significant oscillation in serum-shocked HepG2 cells. DEC2 interacted with CCAAT/enhancer-binding protein (C/EBP␣), accompanied by formation of a complex with histone deacetylase-1, which suppressed the transcriptional activity of C/EBP␣ to induce the expression of CYP2D6. The oscillation in the protein levels of DEC2 in serum-shocked HepG2 cells was nearly antiphase to that in the mRNA levels of CYP2D6. Transfection of cells with small interfering RNA against DEC2 decreased the amplitude of CYP2D6 mRNA oscillation in serumshocked cells. These results suggest that DEC2 periodically represses the promoter activity of CYP2D6, resulting in its circadian expression in serum-shocked cells. DEC2 seems to constitute a molecular link through which output components from the circadian clock are associated with the time-dependent expression of hepatic drug-metabolizing enzyme

Dietary supplementation with essence of chicken enhances daily oscillations in plasma glucocorticoid levels and behavioral adaptation to the phase-shifted environmental light–dark cycle in mice

Maintenance of circadian rhythms is essential to many aspects of human health, including metabolism and neurological and psychiatric well-being. Chronic disruption of circadian clock function is implicated in increasing the risk of metabolic syndrome, cardiovascular events and development of cancers. However, there are little approaches to reinforce the function of circadian clock for prevention of these diseases. Essence of Chicken (EC) is a nutritional supplement that is traditionally made by extracting water soluble substances derived from cooking the whole chicken. In this study, we found that dietary supplementation with EC enhanced circadian oscillation of glucocorticoid secretion in mice, and this was accompanied by enhancement of circadian oscillation in the adrenal expression of steroidogenic acute regulatory (StAR) protein that mediates the rate-limiting step of glucocorticoid synthesis. Furthermore, EC facilitated re-entrainment of behavioral rhythm in mice when phase of the light–dark cycle was suddenly advanced. These results suggest that intake of EC has enhancement effect on circadian clock function in mice, which may contribute to sustain health and also offer new preventive strategies against circadian-related diseases

Optimizing the dosing schedule of l-asparaginase improves its anti-tumor activity in breast tumor-bearing mice

Proliferation of acute lymphoblastic leukemic cells is nutritionally dependent on the external supply of asparagine. l-asparaginase, an enzyme hydrolyzing l-asparagine in blood, is used for treatment of acute lymphoblastic leukemic and other related blood cancers. Although previous studies demonstrated that l-asparaginase suppresses the proliferation of cultured solid tumor cells, it remains unclear whether this enzyme prevents the growth of solid tumors in vivo. In this study, we demonstrated the importance of optimizing dosing schedules for the anti-tumor activity of l-asparaginase in 4T1 breast tumor-bearing mice. Cultures of several types of murine solid tumor cells were dependent on the external supply of asparagine. Among them, we selected murine 4T1 breast cancer cells and implanted them into BALB/c female mice kept under standardized light/dark cycle conditions. The growth of 4T1 tumor cells implanted in mice was significantly suppressed by intravenous administration of l-asparaginase during the light phase, whereas its administration during the dark phase failed to show significant anti-tumor activity. Decreases in plasma asparagine levels due to the administration of l-asparaginase were closely related to the dosing time-dependency of its anti-tumor effects. These results suggest that the anti-tumor efficacy of l-asparaginase in breast tumor-bearing mice is improved by optimizing the dosing schedule. Keywords: l-asparaginase, Asparagine, Solid tumor, Chrono-pharmacotherap