Effects of interferon-alpha, interferon-gamma and cAMP on the transcriptional regulation of the serotonin transporter

Comprehensive review of hepatitis C for psychiatrists: risks, screening, diagnosis, treatment, and interferon-based therapy complications

Hepatitis C is an RNA virus responsible for chronic infection in at least 4 million Americans. Patients are often unaware that they have contracted the virus until the appearance of long-term consequences of the infection, primarily cirrhosis and hepatocellular carcinoma. Many patients with hepatitis C have comorbid psychiatric and/or substance abuse disorders. Treatments for hepatitis C infection are based on interferon-alfa therapy and have shown increasing effectiveness in recent years; however, interferon-alfa therapy also poses significant risks for physical and neuropsychiatric side effects. Since psychiatrists often serve as primary caregivers for patients who are at higher risk for hepatitis C infection, knowledge about the diagnosis, prognosis, and treatment of this disease is needed. In the first half of this article, the authors review the epidemiology, transmission, pathophysiology and disease course of hepatitis C, as well as the neuropsychiatric complications of hepatitis C infection. They also discuss the incidence of comorbid psychiatric disorders in patients with hepatitis C infection and consider the impact of the infection on patients' quality of life. The authors then provide an overview of the clinical management of HCV infection, including screening procedures, decision-making about treatment, available treatments (interferon-alfa, pegylated interferon-alpha, combination therapy with interferon and ribavirin) and their side effects and potential drug-drug interactions, and prediction of treatment response. The authors then discuss management of the neuropsychiatric complications of treatment with interferon-alpha and ribavirin, including depression, mania and psychosis, and cognitive and neurological complications. The final section of the article focuses on special issues related to the treatment of hepatitis C infection in patients with substance abuse or dependence and/or other comorbid psychiatric illness.

Interferon, tryptophan and depression

Depression is a frequent comorbid disorder of many inflammatory diseases and it is suggested that brain inflammatory processes have a pathogenic role in mood dysregulation. Several immunocompromised patients have been treated with cytokines and long-term treatments have resulted in a variety of neuropsychiatric side-effects. The objective of the study was to present evidence for an association between the induction of neuropsychiatric side-effects during treatment with interferon-α (IFN-α) and changes in serotonergic and immunological parameters. Moreover, the use of IFN-α-induced depression as a paradigm for research into the pathophysiology of depressive disorders in general will be discussed. This literature review focused on the relationships between tryptophan, serotonin, cytokines and depression associated with interferon treatment. Immunotherapy with IFN-α influences several immunological and serotonergic parameters, and induces in most patients neurovegetative, somatic and depressive symptoms. Literature findings indicate that the development of depressive symptoms in patients undergoing cytokine therapy are secondary to cytokine induction and could be mediated by a reduced availability of tryptophan to the brain, resulting ultimately in decreased serotonergic activity. Changes in the metabolism of tryptophan and consequently of serotonin may play a role in the pathophysiology of interferon-induced depression. Studies on interferon-induced neuropsychiatric side-effects may be a promising research paradigm and shed light on the role of immunological and serotonergic factors in the pathogenesis of depressive disorders in general. However, first the appropriate symptomatology of the interferon-induced depressive states has to be documented.

Depression induced by treatment with interferon-alpha in patients affected by hepatitis C virus

BACKGROUND

Several studies found a high incidence rate of neuro-psychiatric complications during long-term therapy with interferon alpha (IFNalpha), e.g. slowness, severe fatigue, hypersomnia, lethargy, depressed mood, mnemonic troubles, irritability, short temper, emotional lability, social withdrawal, and lack of concentration. The aim of this study was to examine the incidence of depressed mood and major depression in patients who were treated with IFNalpha.

METHODS

30 patients, affected by chronic active C-hepatitis, have been evaluated at baseline and 3 months after IFNalpha treatment. The evaluation consisted of psychometric assessments employing the DSM-IV criteria and the Montgomery Asberg Depression Rating Scale (MADRS).

RESULTS

At end-point, 40.7% of the patients suffered from a full blown major depression, according to the DSM-IV criteria for major depression. IFNalpha treatment induced a significant increase in the MADRS score from baseline to 3 months later. The MADRS items which were significantly increased at end-point were: expressed and unexpressed sadness; irritability; insomnia; loss of appetite; and asthenia.

DISCUSSION

The results show that prolonged IFNalpha treatment may induce depressive symptoms and major depression in a considerable number of subjects.

Side effects of therapy of hepatitis C and their management

Interferon and ribavirin combination therapy for chronic hepatitis C produces a number of well-described side effects that are dominated by fatigue, influenza-like symptoms, hematologic abnormalities, and neuropsychiatric symptoms. Combination therapy with pegylated interferons (peginterferon alfa-2a and alfa-2b) yields an adverse event profile similar to standard interferon, although the frequency of certain adverse events may vary by preparation. Premature withdrawal from therapy due to adverse events was required in 10% to 14% of participants in registration trials of these agents. Most adverse events were safely and effectively managed by dose reduction using predetermined criteria. The most common indications for dose reduction were hematologic abnormalities, such as anemia and neutropenia, with the latter more frequent in peginterferon treatment arms. Recent data suggest that maintaining adherence to a prescribed treatment regimen can enhance antiviral response. Strategies to maximize adherence are being developed and, in the future, may include early identification of and therapy for depression and the selective use of hematopoietic growth factors to ameliorate hematologic abnormalities.

Side effects of therapy of hepatitis C and their management

Interferon and ribavirin combination therapy for chronic hepatitis C produces a number of well-described side effects that are dominated by fatigue, influenza-like symptoms, hematologic abnormalities, and neuropsychiatric symptoms. Combination therapy with pegylated interferons (peginterferon alfa-2a and alfa-2b) yields an adverse event profile similar to standard interferon, although the frequency of certain adverse events may vary by preparation. Premature withdrawal from therapy due to adverse events was required in 10% to 14% of participants in registration trials of these agents. Most adverse events were safely and effectively managed by dose reduction using predetermined criteria. The most common indications for dose reduction were hematologic abnormalities, such as anemia and neutropenia, with the latter more frequent in peginterferon treatment arms. Recent data suggest that maintaining adherence to a prescribed treatment regimen can enhance antiviral response. Strategies to maximize adherence are being developed and, in the future, may include early identification of and therapy for depression and the selective use of hematopoietic growth factors to ameliorate hematologic abnormalities.

Paroxetine for the treatment of interferon-alpha-induced depression in chronic hepatitis C

BACKGROUND

Psychiatric side-effects may require dose reduction or premature discontinuation of interferon therapy in chronic hepatitis C. New strategies are needed in order to prevent the premature termination of interferon therapy.

AIM

To evaluate prospectively the efficacy and tolerability of antidepressant therapy (paroxetine, a selective serotonin reuptake inhibitor) in patients with chronic hepatitis C treated with interferon-alpha who have developed interferon-induced major depression.

METHODS

A sub-group of 14 individuals from 121 consecutively treated hepatitis C patients developed substance-induced major depression without suicidal ideation during interferon-alpha treatment. The individuals in this sub-group received paroxetine after the occurrence of depression (20 mg daily until termination of interferon therapy). Diagnostic scores for depression (and anger-hostility) were obtained in a repeated measures design (Hospital Anxiety and Depression Scale and Symptom Checklist 90 Items Revised).

RESULTS

Eleven of the 14 patients (78.6%) with interferon-induced major depression were able to complete interferon-alpha therapy as scheduled under concomitant paroxetine treatment (three dropouts: insufficient improvement of depression, occurrence of epileptic seizures, paroxetine-induced nausea/dizziness). Within 4 weeks after the start of paroxetine medication, depression scores declined significantly in all patients.

CONCLUSIONS

Our data suggest that concomitant therapy with paroxetine is an effective way to treat interferon-induced depression in patients with chronic hepatitis C.

Interferon alpha (IFNalpha) and psychiatric syndromes: a review

Interferon alpha (IFNalpha) is used for the treatment of several disorders, such as chronic hepatitis or malignant melanoma. During the therapy, IFNalpha may cause severe neuropsychiatric syndromes including depression with suicidal ideation, paranoid psychoses, or confusional states. The reasons and management of these side effects are widely unknown. Our aim is to review research evidence for the contribution of IFNalpha for the etiopathology of psychiatric syndromes. Therefore, research findings of neuropsychiatric syndromes induced by IFNalpha treatment, the putative mechanisms underlying those syndromes, and their treatment are-reviewed. Furthermore, neuropsychiatric syndromes in diseases with high IFNalpha levels such as systemic lupus erythematosus (SLE) are discussed. Finally, the question is addressed whether IFNalpha may contribute to the etiopathology of endogenous psychiatric disorders. IFNalpha may cause psychiatric syndromes in a subset of treated patients. The underlying pathogenetic mechanisms include various effects on neuroendocrine, cytokine, and neurotransmitter systems. Research data on the role of IFNalpha in the pathogenesis of endogenous psychiatric disorders are conflicting. Future research should improve our understanding of the role of IFNalpha for the etiopathology of psychiatric syndromes and has an impact on treatment of IFNalpha-induced psychiatric syndromes.

Increased depressive ratings in patients with hepatitis C receiving interferon-alpha-based immunotherapy are related to interferon-alpha-induced changes in the serotonergic system

There is now evidence that repeated administration of interferon-alpha (IFN-alpha) to patients with chronic active hepatitis and cancers induces depressive symptoms. There is also evidence that induction of the cytokine network modulates the serotonergic system and that major depression is related to activation of the cytokine network and disturbances in the serotonergic metabolism. The aims of this study were to examine the effects of IFN-alpha-based immunotherapy on the development of depressive symptoms in relation to its effects on plasma tryptophan and kynurenine and serum serotonin (5-HT). Eighteen patients affected by chronic active hepatitis C were treated with IFN-alpha (3-6 million units subcutaneously three to six times a week for 6 months) and had measurements of the previous parameters before starting immunotherapy and 2, 4, 16, and 24 weeks later. Severity of depression and anxiety were measured with the Montgomery-Asberg Depression Rating Scale (MADRS) and the Hamilton Rating Scale for Anxiety (HAM-A) scale, respectively. Immunochemotherapy with IFN-alpha (1) significantly increased the MADRS and HAM-A scores and serum kynurenine concentrations and (2) significantly reduced plasma tryptophan and serum 5-HT concentrations. IFN-alpha-based immunotherapy significantly increased the kynurenine per tryptophan quotient, which estimates the activity of indoleamine 2,3-dioxygenase, the major tryptophan-catabolizing enzyme, which is induced by IFNs. There are significant relationships between the IFN-alpha-induced changes in the MADRS score and serum kynurenine (positive) and 5-HT (negative) concentrations. Immunotherapy with IFN-alpha significantly increases the severity of depressive symptoms. The latter is related to changes in the serotonergic system, such as depletion of serum 5-HT and induction of the catabolism of tryptophan to kynurenine. It is suggested that the IFN-alpha-induced changes in the serotonergic turnover could play a role in the development of IFN-alpha-induced depressive symptoms.

Immunotherapy with interferon-alpha in patients affected by chronic hepatitis C induces an intercorrelated stimulation of the cytokine network and an increase in depressive and anxiety symptoms

Immunotherapy with interferon-alpha (IFNalpha) may induce depressive symptoms, anxiety and major depression when administered for at least 1-3 months at a dose of 3-10 MUI daily, twice or three times a week. Previously, it has been shown that immunotherapy with interleukin-2 (IL-2) significantly induces the cytokine network, as measured by increases in serum IL-6, IL-10 and the IL-2 receptor (IL-2R), and that the immunotherapy-induced changes in the cytokine network are significantly correlated with the increases in depression ratings. The main aim of this study was to examine the effects of immunotherapy with IFNalpha on the cytokine network in relation to changes in depression and anxiety ratings. Fourteen patients, affected by chronic active C-hepatitis, were treated with IFNalpha (3-6 MUI s.c. three/six times a week for 6 months) and had measurements of serum IFN-gamma (IFNgamma), IL-2, IL-6, IL-6R, IL-8 and IL-10 before starting therapy and 2, 4, 16 and 24 weeks after immunotherapy with IFNalpha. Severity of depression and anxiety were measured with the Montgomery-Asberg Depression Rating Scale (MADRS) and the Hamilton Anxiety Rating Scale (HAM-A), respectively. Repeated measure (RM) design ANOVAs showed significantly higher MADRS and HAM-A scores 2-4 weeks and 4-6 months after starting IFNalpha-based immunotherapy than at baseline. RM design ANOVAs showed significantly higher serum IL-6 and IL-8 levels 2-4 weeks after starting IFNalpha-based immunotherapy and higher serum IL-10 levels 2-4 weeks and 4-6 months after starting therapy than at baseline. There were significant relationships between the IFNalpha-induced changes in serum IL-6 or IL-8 and the depression and anxiety scores. The findings show that IFNalpha-based immunotherapy induces the cytokine network and that IFNalpha-induced increases in IL-6 predicts the development of depressive symptoms. Depressive symptoms following IFNalpha treatment may be secondary to cytokine induction, including that of IL-6.

Treatment with interferon-alpha (IFN alpha) of hepatitis C patients induces lower serum dipeptidyl peptidase IV activity, which is related to IFN alpha-induced depressive and anxiety symptoms and immune activation

We have shown that treatment with interleukin-2 (IL-2) or interferon-alpha (IFN alpha) may induce depressive symptoms and activation of the cytokine network and that IL-2 treatment may diminish serum dipeptidyl pepdidase IV (DPP IV) activity. DPP IV (EC 3.4.14.5) is a membrane bound serine protease which catalyzes the cleavage of some cytokines and neuroactive peptides which modulate T cell activity. The aims of the present study were to examine the effects of IFN alpha-based immunotherapy on serum DPP IV activity in relation to induction of the inflammatory response system. In 18 patients with chronic active hepatitis C, we determined the Montgomery and Asberg Rating Scale (MADRS), the Hamilton Anxiety Rating Scale (HAM-A), serum DPP IV activity, the kynurenine/tryptophan (K/T) quotient, which is an indicator of cytokine (in particular IFN)-induced catabolism of tryptophan, and serum interleukin-8 (IL-8) before starting therapy and 2, 4, 16 and 24 weeks after immunotherapy with IFN alpha. IFN alpha-immunotherapy significantly suppressed serum DPP IV 2--4 weeks and 16--24 weeks after starting IFN alpha-based immunotherapy. The reduction in serum DPP IV activity was more pronounced 16--24 weeks after starting immunotherapy than after 2--4 weeks. The IFN alpha-induced suppression of serum DPP IV activity was significantly correlated to IFN alpha-induced increases in the MADRS and HAM-A and increases in the K/T quotient and serum IL-8. In conclusion, long-term immunotherapy with IFN alpha suppresses serum DPP IV activity and the immunotherapy-induced changes in DPP IV are related to increases in severity of depression, anxiety and activation of the inflammatory response system.

Interferons: potential roles in affect

A review of the literature on interferons was conducted and possible roles in neuropsychiatric disorders with affective disturbances are assessed. Interferons and interferon receptors are present in the limbic system where they appear to exert physiological effects pertinent to affect, most potently when levels rise during CNS infections. Interferons interact closely with cytokines and nitric oxide, signaling molecules implicated in depression. Results from knock-out mice suggest a role for interferon-gamma in moderating fear and anxiety, while other lines of evidence point to a role in arousal and circadian rhythms. The interferon-alpha receptor deploys an arginine methyltransferase affecting RNA editing and splicing, which seem to be disrupted in schizophrenia and bipolar disorder. S-Adenosylmethionine (SAMe), an effective antidepressant, may owe its effects in the latter disorders in part to variations in the strength of interferon-alpha signaling impacting RNA processing. Antiviral effects of interferons are of interest in lieu of viral theories of affective disorders. Finally, the relative levels of interferons gamma and alpha might play important roles in neural, and glial, development, as well as the dialog between the CNS and the immune system.

Mood disorders associated with interferon treatment: theoretical and practical considerations

OBJECTIVE

To review the theoretical and clinical aspects of mood disorders associated with interferon treatment and discuss their management.

DATA SOURCES

Pertinent and selected laboratory/clinical studies, review articles, letters, abstracts, and book chapters on behavioral and mood-related adverse effects of interferons published in English-language journals in the past two decades were identified by MEDLINE (June 1980-June 2000) and manual searches. DATA SELECTION AND DATA EXTRACTION: All of the publications identified were reviewed, and the relevant data were included. Studies not using criteria for psychiatric diagnosis or instruments for psychiatnc monitoring were excluded.

DATA SYNTHESIS

Clinical observations and limited research data suggest that interferon treatment may be associated with mood disorders. Mood-related symptoms induced by interferons emerge in a few days or weeks and tend to be dose dependent. Their severity may necessitate discontinuation of interferon therapy and/or the use of antidepressant or antimanic agents. The mechanisms responsible for inducing or exacerbating mood disorders in interferon-treated patients have not been elucidated. There is limited evidence implicating alterations in the serotonin system.

CONCLUSIONS

While interferon therapy may trigger or induce mood-related symptoms, preexisting or stable concurrent mood disorders in remission do not necessarily constitute a contraindication to treatment with interferons. Mood disorders associated with interferon treatment can present clinical challenges. However, they may promote our understanding of mood disorders in the context of the current biologic theories of depression and mania.

Effects of short- and long-term exposure to c-AMP and c-GMP on the noradrenaline transporter

The effects of short- and long-term exposure of cells to elevated cyclic adenosine monophosphate (c-AMP), using dibutyryl-c-AMP, 8-bromo-c-AMP, cholera toxin or forskolin, or cyclic guanosine monophosphate (c-GMP), using dibutyryl-c-GMP or 8-bromo-c-GMP, on the activity and expression of the noradrenaline transporter (NAT) were examined. Short- or long-term c-GMP elevation had no effects on (3)H-noradrenaline uptake by rat PC12 phaeochromocytoma cells or human SK-N-SH-SY5Y neuroblastoma cells. Short-term c-AMP elevation (for 17 min experiment duration) caused a decrease in (3)H-noradrenaline uptake by PC12 cells, but had no effects on SK-N-SH-SY5Y cells or COS-7 cells transfected with human or rat NAT cDNA. c-AMP did not affect (3)H-nisoxetine binding to PC12 cells. Long-term (24 h) exposure to elevated c-AMP levels caused a decrease in (3)H-noradrenaline uptake and NAT mRNA in PC12 cells, but had no effects on SK-N-SH-SY5Y cells and caused a small increase in (3)H-noradrenaline uptake in COS-7 cells heterologously expressing rat or human NAT. Hence, c-AMP, but not c-GMP, causes a cell type-dependent reduction in NAT activity after short-term exposure and a reduction in NAT expression after long-term exposure.

Involvement of the actin cytoskeleton in the regulation of serotonin transporter (SET) activity: possible mechanism underlying SET regulation by protein kinase C

Our previous report has revealed that PKC activation by 12-O-tetradecanoylphorbol 13-acetate (TPA) inhibited the uptake activity of serotonin transporter (SET), via an indirect mechanism unknown, but not likely via direct phosphorylation of SET by PKC (Sakai et al., 1997. J. Neurochem. 68, 2618-2624). To elucidate whether PKC can directly phosphorylate SET in vivo, FLAG-tagged SET (FLAG-SET) was expressed in COS-7 cells and the TPA-induced incorporation of (32)P into immunoprecipitated FLAG-SET was examined. PKC activation with TPA caused no phosphorylation of FLAG-SET expressed in COS-7 cells. On the other hand, morphological change associated with the disruption of filamentous actin (F-actin) was seen in TPA-treated COS-7 cells. Therefore, we studied the effects of cytochalasin D, an inhibitor of actin polymerization, on the uptake activity of the serotonin transporter (SET) to elucidate whether the actin cytoskeleton modulates the SET uptake activity. The treatment with cytochalasin D inhibited the uptake activity of both native and recombinant SET in a concentration-dependent manner. Eadie-Hofstee analysis revealed that cytochalasin D down-regulated the recombinant SET uptake activity by reducing the V(max), but not the K(m), mimicking the result observed in TPA-induced inhibition of SET activity (Sakai et al., 1997. J. Neurochem. 68, 2618-2624). The cytochalasin D-induced inhibition of SET activity was partially, but significantly, reversed by jasplakinolide, a cell permeable stabilizer of F-actin, whereas TPA-induced inhibition of SET activity was not reversed by jasplakinolide. To elucidate whether the subcellular localization of SET was changed in response to cytochalasin D or TPA, we expressed the SET fused with the green fluorescent protein (SET-GFP) in COS-7 cells and observed the subcellular distribution of SET-GFP under a confocal laser scanning fluorescent microscope. Neither cytochalasin D nor TPA markedly changed the SET-GFP cellular localization, although these drugs caused morphological change in the GFP-transfected COS-7 cells. In addition, SET activity was not altered by the treatment with either colchicine, an inhibitor of microtubule polymerization, or taxol, a stabilizer of microtubule polymerization. These results suggest that the SET uptake activity was regulated by the state of the actin cytoskeleton and that TPA exerts its inhibitory action on SET activity, in part, via disruption of F-actin and subsequent morphological change in cells.

Early depressive symptoms in cancer patients receiving interleukin 2 and/or interferon alfa-2b therapy

PURPOSE

Depressive symptomatology is frequently associated with interleukin (IL)-2 and interferon alfa-2b (INFalpha-2b) therapy in cancer patients. The objective of the present study was to evaluate the depressive and anxiety symptoms induced by IL-2 and/or INFalpha-2b in cancer patients during the first days of cytokine immunotherapy.

PATIENTS AND METHODS

The study included 48 patients with renal cell carcinoma or melanoma. Patients were treated either with subcutaneous IL-2, alone (n = 20) or in combination with INFalpha-2b (n = 6); or with INFalpha-2b alone, administered subcutaneously at a low dose (n = 8) or intravenously at a high dose (n = 14). Depressive symptoms were evaluated using the Montgomery and Asberg Depression Rating Scale (MADRS), and anxiety symptoms were evaluated using the Covi scale. Evaluations were performed just before initiation of treatment (day 1) and on days 3 and 5 of treatment.

RESULTS

Patients treated with IL-2 alone or in association with INFalpha-2b had significantly higher MADRS scores after 5 days of cytokine therapy, and patients who received both cytokines had increased scores on day 3. In contrast, patients treated with INFalpha-2b alone did not have varying MADRS scores during the course of treatment. Cytokine therapy had no effect on anxiety, except in patients treated with IL-2 in combination with INFalpha-2b. In these patients, the enhancement in anxiety scores that was observed on day 5 was mainly attributable to increased somatic complaints.

CONCLUSION

IL-2 and INFalpha-2b have differential effects on mood, and IL-2 therapy induces depressive symptoms early in treatment.

Serotonin transporter production and degradation rates: studies with RTI-76

The objective of this study was to examine the turnover of the serotonin transporter (SERT) by determining its production rate (r), degradation rate constant (k) and half-life of recovery (t1/2). The turnover of SERT was determined from the rate of recovery of binding after administration of RTI-76, an irreversible inhibitor of ligand binding. In preliminary studies, in vitro incubation of rat cerebral cortex with RTI-76 produced a wash and temperature resistant inhibition of SERT binding densities (Bmax). Citalopram protected against the RTI-76-induced inhibition of SERT binding. Following 6 h of in vivo intracerebroventricular injections of 100 nmol of RTI-76, there was a dose- and time-dependent reduction (- 60%) of SERT binding in hippocampus and striatum, without a change in the Kd. SERT binding densities recovered over several days, reaching control levels by day 14. The recovery curve fit the standard model of protein synthesis and degradation. The turnover parameters of SERT were determined in hippocampus and striatum, regions that receive serotonergic innervation from the dorsal and median midbrain raphe nuclei, respectively. In the hippocampus, the production rate constant was 2.36 fmol mg protein (-1)h(-1); the degradation rate constant was 0.0077 h(-1); and the half-life of the SERT recovery was 3.4 days. The values in the striatum were similar. The decrease and recovery of [3H]-5-HT uptake correlated highly (r = 0.93) with the recovery of SERT binding.