Władysław Lasoń

Basic mechanisms of antiepileptic drugs and their pharmacokinetic/pharmacodynamic interactions: an update.

This article aims to summarize the current views of AED action and the promising new targets for the pharmacotherapy of epilepsy. In the first section of this paper, a neurobiological basis of epilepsy treatment and brief pharmacological characteristics of classical and new AEDs will be presented. In the second part, the results of experimental studies that have combined AEDs with similar or different mechanisms of action will be discussed.

A new animal model of (chronic) depression induced by repeated and intermittent lipopolysaccharide administration for 4 months

Chronic activation of immune-inflammatory and oxidative and nitrosative stress (O&NS) pathways plays an important role in the pathophysiology of clinical depression. Increased IgA responses directed against LPS of gram-negative bacteria, indicating increased bacterial translocation, may be one of the drivers underpinning these pathways. There is a strong association between signs of bacterial translocation and chronicity of depression and O&NS, but not pro-inflammatory cytokines. The aims of the present study were to: (1) develop a new neurobehavioral model of (chronic) depression (anhedonic behavior) that may reflect chronic LPS stimulation and is associated with increased oxidative stress, and (2) to delineate the effects of fluoxetine on this new depression model. We established that in female mice repeated LPS injections once daily for 5 days (from 750 μg/kg to a maximal dose 1250 μg/kg; increasing doses for the first three days which were then gradually decreased on day 4 and 5) at a one-month interval and this repeated for 4 consecutive months induced chronic anhedonia (estimated by the preference to drink a 1% sucrose) lasting for at least 7 weeks. Chronic LPS administration significantly decreased thymus weight, proliferative activity of splenocytes, production of interferon (IFN)γ and interleukin-(IL)10, and increased superoxide and corticosterone production. Treatment with fluoxetine for 3 weeks abolished the neurobehavioral effects of LPS. The antidepressant effect of fluoxetine was accompanied by increased production of IL-10 and reduced superoxide and corticosterone production. Our results suggest that repeated intermittent LPS injections to female mice may be a useful model of chronic depression and in particular for the depressogenic effects of long standing activation of the toll-like receptor IV complex.

Neuroprotective effects of MAPK/ERK1/2 and calpain inhibitors on lactacystin-induced cell damage in primary cortical neurons

The dysfunction of the proteasome system is implicated in the pathomechanism of several chronic neurodegenerative diseases. Lactacystin (LC), an irreversible proteasome inhibitor, induces cell death in primary cortical neurons, however, the molecular mechanisms of its neurotoxic action has been only partially unraveled. In this study we aimed to elucidate an involvement of the key enzymatic pathways responsible for LC-induced neuronal cell death. Incubation of primary cortical neurons with LC (0.25-50 μg/ml) evoked neuronal cell death in concentration- and time-dependent manner. Lactacystin (2.5 μg/ml; 6.6μM) enhanced caspase-3 activity, but caspase-3 inhibitor, Ac-DEVD-CHO did not attenuate the LC-evoked cell damage. Western blot analysis showed a time-dependent, prolonged activation of MAPK/ERK1/2 pathway after LC exposure. Moreover, inhibitors of MAPK/ERK1/2 signaling, U0126 and PD98052 attenuated the LC-evoked cell death. We also found that LC-treatment resulted in the induction of calpains and calpain inhibitors (MDL28170 and calpeptin) protected neurons against the LC-induced cell damage. Neuroprotective action of MAPK/ERK1/2 and calpain inhibitors were connected with attenuation of LC-induced DNA fragmentation measured by Hoechst 33342 staining and TUNEL assay. However, only MAPK/ERK1/2 but not calpain inhibitors, attenuated the LC-induced AIF (apoptosis inducing factor) release. Further studies showed no synergy between neuroprotective effects of MAPK/ERK1/2 and calpain inhibitors given in combination when compared to their effects alone. The obtained data provided evidence for neuroprotective potency of MAPK/ERK1/2 and calpain, but not caspase-3 inhibition against the neurotoxic effects of LC in primary cortical neurons and give rationale for using these inhibitors in the treatment of neurodegenerative diseases connected with proteasome dysfunction.

Single centre 20 year survey of antiepileptic drug-induced hypersensitivity reactions.

BACKGROUND Epilepsy is a chronic neurological disease which affects about 1% of the human population. There are 50 million patients in the world suffering from this disease and 2 million new cases per year are observed. The necessary treatment with antiepileptic drugs (AEDs) increases the risk of adverse reactions. In case of 15% of people receiving AEDs, cutaneous reactions, like maculopapular or erythematous pruritic rash, may appear within four weeks of initiating therapy with AEDs. METHODS This study involved 300 epileptic patients in the period between September 1989 and September 2009. A cutaneous adverse reaction was defined as a diffuse rash, which had no other obvious reason than a drug effect, and resulted in contacting a physician. RESULTS Among 300 epileptic patients of Neurological Practice in Kielce (132 males and 168 females), a skin reaction to at least one AED was found in 30 patients. As much as 95% of the reactions occurred during therapies with carbamazepine, phenytoin, lamotrigine or oxcarbazepine. One of the patients developed Stevens-Johnson syndrome. CONCLUSION Some hypersensitivity problems of epileptic patients were obviously related to antiepileptic treatment. Among AEDs, gabapentin, topiramate, levetiracetam, vigabatrin, and phenobarbital were not associated with skin lesions, although the number of patients in the case of the latter was small.

Antidepressants attenuate the dexamethasone-induced decrease in viability and proliferation of human neuroblastoma SH-SY5Y cells: a involvement of extracellular regulated kinase (ERK1/2).

Excessive glucocorticoid levels in depressed patients have been associated with atrophic changes in some brain regions, but only few studies suggest that some antidepressants can interfere with deleterious effect of glucocorticoids on neuronal cells. The aim of the present study was to examine the effect of dexamethasone (DEX), a synthetic glucocorticoid and some antidepressants from different chemical groups (imipramine, desipramine, amitriptyline, citalopram, fluoxetine, reboxetine and tianeptine) on SH-SY5Y cells cultured in the medium containing steroid-free serum. DEX in concentrations from 1 to 100 μM did not change LDH release but exposure to 10 μM and 100 μM DEX for 24, 48 and 72 h caused a significant reduction in cell viability and proliferation as confirmed by MTT reduction and BrdU ELISA assays, respectively. Twenty four-hour incubation of cells with antidepressants (0.05-10 μM) and DEX (10 μM) showed that imipramine, amitriptyline, desipramine, citalopram and fluoxetine at concentrations from 0.1 up to 1 μM, reboxetine (0.1 μM) and tianeptine (0.05 μM) prevented the DEX-induced decreases in cell viability and proliferation rate. The protective effects of antidepressants were ameliorated by inhibitors of MAPK/ERK1/2, but not PI3-K/Akt pathway as shown for imipramine, fluoxetine and reboxetine. Moreover, Western blot analysis showed the decrease in the activated form of ERK1/2 (p-ERK) after DEX treatment and this effect was inhibited by imipramine. Thus, the reduction in SH-SY5Y cell viability caused by DEX appears to be related to its antiproliferative activity and some antidepressant drugs in low concentrations attenuate this effect by mechanism which involves the activation of MAPK/ERK1/2 pathway.

Stimulatory effect of antidepressant drug pretreatment on progression of B16F10 melanoma in high-active male and female C57BL/6J mice

The effect of a two-week desipramine or fluoxetine (10 mg/kg, i.p.) pretreatment on B16F10 melanoma growth in 3-5 month old female and male C57BL/6J mice differing in behavioral characteristics (high- vs. low-active) was compared. Antidepressant pretreatment increased metastasis formation, shortened the survival, decreased splenocyte anti-tumor natural killer cell cytotoxicity (in vitro), and the pro-inflammatory cytokine IL-12p40, IFN-γ production while it increased anti-inflammatory cytokine IL-10 production in high-active males (desipramine) or females (fluoxetine). The obtained results emphasize a stimulatory effect of pretreatment with antidepressants on progress of B16F10 melanoma that depends on gender and behavioral characteristics of the animal.

Inhibition of 2,4-dinitrofluorobenzene-induced contact hypersensitivity reaction by antidepressant drugs

BACKGROUND Contact hypersensitivity (CHS) induced by a topical application of hapten - 2,4-dinitrofluorobenzene (DNFB), is a T cytotoxic (Tc)1-cell-mediated antigen-specific type of skin inflammation. Recently, it has been shown that antidepressant drugs inhibit the T helper (Th)1-mediated CHS reaction induced by picryl chloride. The aim of present study was to establish the effect of two-week desipramine or fluoxetine administration on the CHS reaction induced by DNFB. METHODS Balb/c (H-2(d)) male mice were divided into six groups: 1) vehicle-treated negative control group; 2) desipramine-treated negative control group; 3) fluoxetine-treated negative control group; 4) vehicle-treated DNFB group (positive control group); 5) desipramine-treated DNFB group; 6) fluoxetine-treated DNFB group. T lymphocytes proliferation was determined by incorporation of [(3)H]-thymidine to DNA of concanavalin A stimulated cells. ELISA test was used for estimation of cytokines production. RESULTS The antidepressants significantly suppressed the CHS reaction mediated by Tc1 cells: desipramine by 55% and fluoxetine by 54% compared to the positive control. Moreover, the antidepressants decreased the proliferative activity of splenocytes and the ability of splenocytes to produce interleukin (IL)-6 and interferon (IFN)-γ and increased IL-10 production by the lymph node (LN) cells of DNFB-treated mice. CONCLUSION The results of the present study show that the Tc1-dependent reactivity to DNFB is significantly suppressed by antidepressant drugs, which suggests their inhibitory effect on Tc1 mediated immunity.

Inhibitory effect of antidepressants on B16F10 melanoma tumor growth.

BACKGROUND Antidepressant drugs, like fluoxetine, a selective serotonin reuptake inhibitor, desipramine, a nonselective noradrenaline reuptake inhibitor, and mirtazapine, an antagonist of noradrenaline α2 auto- and heteroreceptors, are widely used for the treatment of depressive symptoms in cancer patients. Since these antidepressants have different activities targeting the immune system, they might also modulate tumor growth in cancer patients. METHODS In the present study, we investigated the effects of administration of antidepressant drugs: fluoxetine, desipramine and mirtazapine on B16F10 melanoma tumor growth. These drugs were administered intraperitoneally (ip) for 17 days after subcutaneous injection of B16F10 melanoma cells to male C57BL/6J mice. RESULTS Fluoxetine significantly inhibited melanoma solid tumor growth and desipramine tended to decrease this parameter whereas mirtazapine had no effect. CONCLUSION The inhibitory effect of fluoxetine on melanoma growth was associated with an increased mitogen-induced T cell proliferation which may at least partly participate in the mechanism of the antitumor effect of this antidepressant. It appears that the inhibitory effect of fluoxetine on tumor growth is not related with changes in cytokine levels except for IL-10.

Crosstalk between contact hypersensitivity reaction and antidepressant drugs

Allergic contact dermatitis is a delayed-type hypersensitivity reaction mediated by hapten-specific T cells. Many cell types, inflammatory mediators and cytokines are involved in this reaction. Contact hypersensitivity is a self-limited reaction and can be regulated at different levels. Because it is known that disturbances in the immune system underpin the onset of depression and that antidepressant drugs have immunomodulatory effects, it can be hypothesized that antidepressants may have some efficacy in the treatment of contact hypersensitivity. There are some reports on the effectiveness of antidepressants in the inhibition of cutaneous sensitization in mice, and the aim of this narrative review is to assess the evidence for the effectiveness of antidepressant drugs in reducing the recurrence of contact hypersensitivity reactions.