Chronic variable stress facilitates tumoral growth: reversal by imipramine administration

Prostate cancer and antidepressants: A nationwide population-based nested case-control study

BACKGROUND

We aimed to evaluate the association between antidepressant and prostate cancer by comparing exposures to antidepressants between those with and without prostate cancer.

METHODS

A nationwide insurance claims database was used to identify our case subjects. Age- and gender-matched controls were selected at a 1:5 ratio. Conditional logistic regression model was used.

RESULTS

11,515 patients with prostate cancer were identified and matched with 55,373 controls. No increased associations between prostate cancer and most classes of antidepressants were found. However, a positive association with adjusted odds ratios ranged from 1.20 to 1.35 was noted in different doses of imipramine. Nevertheless, this association became statistically insignificant at higher cumulative doses.

CONCLUSIONS

Our results indicate that there is no association between mechanistically dissimilar antidepressants and increased hazard for prostate cancer.

Serum Proteomics Analysis in Rats of Immunosuppression Induced by Chronic Stress

The immune system can be damaged by chronic stress. However, for this process, the involved molecular alterations and their regulatory roles played in immunosuppression still remain unclear. This study was aimed to identify the differences in serum protein expressions that are closely associated with the effect of chronic stress on immune function. Serum protein levels of rats in control group and chronic stress group were measured by iTRAQ analysis. Subsequently, among the 121 differentially expressed proteins screened between the two groups, 46 proteins were upregulated (>1.5-fold, P < 0.05), while 75 proteins were downregulated (<0.67-fold, P < 0.05). Bioinformatics analysis revealed that most of the differentially expressed proteins were in relation with the metabolic, cellular, response stimulus and immune system processes. The significantly differential expression of ceruloplasmin, haptoglobin, catalase and peroxiredoxin-1 were picked out for reconfirmation by ELISA analysis. The results were consistent with those obtained by iTRAQ. What is more, the roles of above-mentioned four proteins, apolipoprotein B-100 and heat-shock protein 90 in immunosuppression induced by chronic stress were discussed. Taken together, these findings may provide a new insight into better understanding the molecular mechanisms of immunosuppression induced by chronic stress.

Invasive Cervical Cancer and Antidepressants: A Nationwide Population-Based Study

To our knowledge, no prior population-based study has been published wherein the primary aim was to evaluate whether an association between psychotropic drug prescription and cervical cancer exists. Herein we have conducted the first study that primarily aimed to determine the association between antidepressants use and risk of invasive cervical cancer in the general population.This is a population-based study utilizing Taiwan's National Health Insurance Research Database. We identified 26,262 cases with invasive cervical cancer and 129,490 controls. We adopted the conditional logistic regression model as the statistical method and adjusted for potential confounding factors.The prescription of selective serotonin reuptake inhibitors (SSRIs) (adjusted OR = 0.93, 95% CI = 0.84-1.04), tricyclic antidepressants (TCAs), monoamine oxidase inhibitors (MAOIs), serotonin norepinephrine reuptake inhibitors (SNRIs), mirtazapine and bupropion, adjusting for cumulative dose, was not associated with an increased, or decreased, risk for invasive cervical cancer. An association between trazodone prescription and invasive cervical cancer was observed (adjusted OR = 1.22, 95% CI = 1.03-1.43).An association between the major classes of antidepressants and invasive cervical cancer was not observed herein. Our preliminary finding regarding a possible association between trazodone and cervical cancer requires replication.

Effects of chronic desipramine pretreatment on open field-induced suppression of blood natural killer cell activity and cytokine response depend on the rat's behavioral characteristics

Effects of 14 consecutive day exposure to desipramine (10mg/kg i.p.), by itself or following chronic open field (OF) exposure, on subsequent neuroimmunological effects of acute (30 min) OF stress and the involvement of individual differences in response to novelty or social position in the anti-depressive responsiveness were investigated. Chronic desipramine pretreatment did not protect against OF stress-induced suppression of blood anti-tumor natural killer cell activity but increased plasma interleukin-10 and decreased interferon-γ and corticosterone concentration. These effects were particularly dangerous for the animals with increased responsivity to stress (desipramine alone) or with low behavioral activity (desipramine after chronic stress).

Use of antidepressants and the risk of breast cancer: a meta-analysis

The goal of this study was to perform a meta-analysis to examine the association between the use of antidepressants (AD) and the risk of breast cancer. We searched the EMBASE and MEDLINE databases from inception through February 25, 2012, using search terms related to ADs and breast cancer. Two evaluators independently reviewed and selected articles and extracted data based on predetermined selection criteria. Pooled effect estimates were obtained by using random- and fixed effects meta-analyses. Of the 3,209 titles identified, 18 articles met the inclusion criteria. The overall risk of breast cancer did not increase among AD users [adjusted odds ratio (aOR) 1.02; 95 % CI 0.96-1.08]. Those who took tricyclic antidepressants (TCAs) or selective serotonin reuptake inhibitors (SSRIs) were not at increased risks of breast cancer. In subgroup meta-analyses, null associations were consistent across the type of AD, funding sources, the number of adjusted variables, medication dose, the ascertainment of exposure, and methodological quality. In subgroup analyses based on exposure duration, a marginal association was observed for the use of SSRIs < 1-2 years (aOR 1.10; 95 % CI 1.02-1.19). However, this effect was attenuated over time and those using SSRIs for more than 1-2 years had no elevated breast cancer risk. These results support the lack of a clinically meaningful association between AD use and the development of breast cancer and provide considerable reassurance. Given that the data collected to date do not support changing the current prescribing patterns for ADs, the important benefits of AD therapy must be considered.

Antidepressants and breast and ovarian cancer risk: a review of the literature and researchers' financial associations with industry

Background

Antidepressant (AD) use has been purported to increase the risk of breast and ovarian cancer, although both epidemiological and pre-clinical studies have reported mixed results [1]–[6]. Previous studies in a variety of biomedical fields have found that financial ties to drug companies are associated with favorable study conclusions [7].

Methods and Findings

We searched English-language articles in MEDLINE, PsychINFO, the Science Citations Index and the Cochrane Central Register of Controlled Clinical Trials (through November 2010). A total of 61 articles that assessed the relationship between breast and ovarian cancer and AD use and articles that examined the effect of ADs on cell growth were included. Multi-modal screening techniques were used to investigate researchers' financial ties with industry. A random effects meta-analysis was used to pool the findings from the epidemiological literature. Thirty-three percent (20/61) of the studies reported a positive association between ADs and cancer. Sixty-seven percent (41/61) of the studies reported no association or antiproliferative effect. The pooled odds ratio for the association between AD use and breast/ovarian cancer in the epidemiologic studies was 1.11 (95% CI, 1.03–1.20). Researchers with industry affiliations were significantly less likely than researchers without those ties to conclude that ADs increase the risk of breast or ovarian cancer. (0/15 [0%] vs 20/46 [43.5%] (Fisher's Exact test P = 0.0012).

Conclusions

Both the pre-clinical and clinical data are mixed in terms of showing an association between AD use and breast and ovarian cancer. The possibility that ADs may exhibit a bi-phasic effect, whereby short-term use and/or low dose antidepressants may increase the risk of breast and ovarian cancer, warrants further investigation. Industry affiliations were significantly associated with negative conclusions regarding cancer risk. The findings have implications in light of the 2009 USPSTF guidelines for breast cancer screening and for the informed consent process.

Effect of imipramine on HT-29 cells' proliferation, cell cycle arrest and apoptosis and its mechanism

AIM: To investigate the effect of imipramine on cell growth, cell cycle and apoptosis of HT-29 colon cancer cells, and to elucidate its molecular mechanism.

METHODS: Human colon cancer HT-29 cells were grown with routine cell cultivation and cells were treated with different concentrations of imiprmine. Cell survival was determined using MTT assay at 24 h, 48 h and 72 h, respectively; cell cycle distribution was assessed by FACS flow cytometery after propidium iodide staining; apoptosis of HT-29 cells was detected using Annexin V/PI methods and DNA ladder assay. Expression level of Eag1 protein was detected by Western blot, and mRNA expressions of p21, p27, CyclinE1 and CDK2 were determined by reverse transcription-polymerase chain reaction.

RESULTS: After treatment with imipramine in HT-29 cells at 24, 48 and 72 h, IC₅₀ were 43, 32 and 22 μmol/L, respectively. Cell viability decreased dose-dependently and time-dependently after treatment with imiprmince in HT 29 cells. Cell cycle arrested during the G₀/G₁ phase accompanied by the induction of apoptosis in a dose-dependent manner. With imipramine increasing, HT-29 cells apoptosis index gradually increased (P < 0.01). Expression level of Eag1 protein was decreased in a dose-dependent manner (P < 0.05). The p21 mRNA and p27 mRNA were up-regulated (P < 0.05), and CDK2 mRNA and CyclinE1 mRNA were suppressed in imipramine-treated HT-29 cells in a dose-dependent manner (P < 0.05).

CONCLUSION: Imipramine, a non-specific inhibitor of Eag1 potassium channel, induces cell growth inhibition, cell-cycle arrest and apoptosis in HT-29 cells through up-regulation of p27 and/or p21.

Behavioral genetics of the depression/cancer correlation: a look at the Ras oncogene family and the 'cerebral diabetes paradigm'

This study investigates the causes of the observed linkage between depression and later onset of cancer. The prevailing view is that cancer in depressed patients results from a weakened immune system. However, molecular biologists have recognized that dysregulation of the ras proto-oncogene results in impaired serotonin and dopamine synthesis manifesting as major depression. A qualitative review of the literature showed that (1) studies using the Minnesota Multiphasic Personality Inventory showed a greater correlation between depression and later cancer onset than those employing other measures and (2) the more related the cancer type was to the Ras oncogene family, the greater the correlation between depression and later cancer onset. These results support the hypothesis that the ras proto-oncogene plays a role in the etiology of depression and could be the common denominator in long-observed depression/cancer linkages. Previous depression/cancer linkage studies are confounded in that they failed to analyze cancer type and accurately diagnose depression.

Chronic mild stress (CMS) revisited: consistency and behavioural-neurobiological concordance in the effects of CMS

The chronic mild stress (CMS) model of depression has high validity but has in the past been criticized for being difficult to replicate. However, a large number of recent publications have confirmed that CMS causes behavioural changes in rodents that parallel symptoms of depression. This review summarizes studies from over sixty independent research groups that have reported decreases in reactivity to rewards, and a variety of other depression-like behaviours, in rats or mice, following exposure to CMS. Together, these changes are referred to as a 'depressive' behavioural profile. Almost every study that has examined the effects of chronic antidepressant treatment in these procedures has reported that antidepressants were effective in reversing or preventing these 'depressive' behavioural changes. (The single exception is a study in which the duration of treatment was too brief to constitute an adequate trial.) There are also a handful of reports of CMS causing significant effects in the opposite direction, termed here an 'anomalous' behavioural profile. There are six neurobiological parameters that have been studied in both 'anhedonic' and 'anomalous' animals: psychostimulant and place-conditioning effects of dopamine agonists; dopamine D2 receptor number and message; inhibition of dopamine turnover by quinpirole, and beta-adrenergic receptor binding. On all six measures, CMS caused opposite effects in animals displaying 'depressive' and 'anomalous' profiles. Thus, there is overwhelming evidence that under appropriate experimental conditions, CMS can cause antidepressant-reversible depressive-like effects in rodents; however, the 'anomalous' profile that is occasionally reported appears to be a genuine phenomenon, and these two sets of behavioural effects appear to be associated with opposite patterns of neurobiological changes.

Phenotypic and functional changes on phagocytic cells recruited at the site of Candida albicans infection after chronic varied stress exposure

The transition of Candida albicans from commensalism to pathogenicity is associated with the immune status of the host; resistance to fungus involves macrophages (Mphi) and polymorphonuclear neutrophils (PMN), which act as effector cells. T-cell function is also involved. Previously, we found that in Wistar rats exposed to chronic varied stress (CVS) immediately after C. albicans infection (Ca-S group) some functions of phagocytic cells, such as killer activity and NO production, were strongly modified compared with unstressed, infected animals (Ca group). We examined the phenotypic and functional changes of these effector cells recruited at the site of C. albicans infection. The recruitment of peritoneal cells (PC) was markedly reduced in Ca-S animals and the arrival of Mphi and PMN was selectively diminished after CVS exposure. The integrin CD11b/CD18, implicated in migration and C. albicans phagocytosis, was downregulated in Mphi of Ca-S animals. The activation markers CD54 and MHC-II were upregulated in Mphi after fungal contact. The expression of CD54 was only changed in Ca-S rats. Finally, TNF-alpha production was reduced in PC of Ca-S animals, suggesting an impairment of functional activity. Taken together, the phenotypic and functional changes detected in effector cells may account for the decreased resistance to candidiasis seen in conjunction with CVS. The changes seen also expand our knowledge of the role of Mphi in the control of C. albicans dissemination.

Cytokines and chronic fatigue syndrome

Chronic fatigue syndrome (CFS) patients show evidence of immune activation, as demonstrated by increased numbers of activated T lymphocytes, including cytotoxic T cells, as well as elevated levels of circulating cytokines. Nevertheless, immune cell function of CFS patients is poor, with low natural killer cell cytotoxicity (NKCC), poor lymphocyte response to mitogens in culture, and frequent immunoglobulin deficiencies, most often IgG1 and IgG3. Immune dysfunction in CFS, with predominance of so-called T-helper type 2 and proinflammatory cytokines, can be episodic and associated with either cause or effect of the physiological and psychological function derangement and/or activation of latent viruses or other pathogens. The interplay of these factors can account for the perpetuation of disease with remission/exacerbation cycles. A T-helper type 2 predominance has been seen among Gulf War syndrome patients and this feature may also be present in other related disorders, such as multiple chemical sensitivity. Therapeutic intervention aimed at induction of a more favorable cytokine expression pattern and immune status appears promising.

Impaired activity of phagocytic cells in Candida albicans infection after exposure to chronic varied stress

OBJECTIVE

Candidiasis is a prototypic opportunistic fungal disease that may follow severe modulations of the immune system of the host. The purpose of this study was to evaluate which innate immune mechanisms involved in the protection against fungal invasion are impaired under stress conditions.

METHODS

Wistar rats were infected intraperitoneally with Candida albicans and immediately exposed to chronic varied stress (CVS) over 10 days (CVS; Ca-S); the fungal burden (CFU), histopathological lesion and ACTH levels were evaluated. Additionally, functional assessment of peritoneal cells (PC) included the phagocytic and anticandidacidal activities and the production of H(2)O(2) and NO.

RESULTS

In the only infected animals (Ca), C. albicans colonization stimulated an efficient inflammatory response, while in Ca-S rats poor tissue reactions were associated with increased CFU in livers and kidneys (p < 0.05, Ca vs. Ca-S). Whereas the phagocytic process was not modified, the candidacidal activity of PC was significantly decreased after the application of CVS (p < 0.001, Ca vs. Ca-S). The H(2)O(2) production by macrophages and neutrophils was downregulated by the infection, and while at early intervals these cells possessed a residual oxidative capacity, by day 10, the production of this metabolite was blocked. Spontaneous NO production by macrophages was significantly increased in both Ca and Ca-S animals (p < 0.001), but in stressed rats, this reactive nitrogen intermediate was noticeably downregulated (p < 0.05, Ca vs. Ca-S). The hyperactivity of hypothalamus-pituitary-adrenal axis after exposure to stress was confirmed by an increase in baseline plasma ACTH levels.

CONCLUSION

These results show that during infection with C. albicans, the exposure to CVS contributes to the spread of the fungus and downregulates critical functions of phagocytic cells involved in the control of this opportunistic pathogen.

Chronic varied stress modulates experimental autoimmune encephalomyelitis in Wistar rats

Stress disturbs homeostasis by altering the equilibrium of various hormones which have a significant impact on immune responses. Few studies have examined the influence of stressors on autoimmune disease in animal models. In our work, we studied the effects of long-term exposure (14 days) to chronic varied stress (CVS) in a model of experimental autoimmune encephalomyelitis (EAE) in Wistar rats. We studied whether the exposure to CVS before or after the immune challenge would correlate with differences in the clinical course of the disease. We also examined whether the CVS would modulate the magnitude of the cellular or the humoral immune response. We observed opposite effects on the clinical signs in animals stressed before or after the immune challenge. The clinical signs of the disease were attenuated in animals stressed before but not after the immune challenge. Relationships were found in the modulation of the clinical severity related to the time of exposure to the CVS, the histological alterations and the proliferative results. Stressed animals with milder clinical signs presented an exacerbated humoral response against myelin antigens while stressed animals with more severe clinical symptoms exhibited a significantly diminished one. Besides, we detected the presence of specific IgG1 associated with the exposure to CVS before the induction of EAE. Our results show that, depending on the timing of the exposure of Wistar rats to the CVS, the neuroendocrine disbalance favors a more pronounced humoral or cellular profile of the response.

Short and long restraint differentially affect humoral and cellular immune functions

The aim of this work was to examine the effect of different periods of restraint on the humoral and cellular immune functions in adult male rats. Short restraint stress (2 h over 2 consecutive days) enhanced the primary serum antibody response to sheep red blood cells. The enhancement of this humoral response was dependent on the restraint period, since long restraint stress (6 h over 4 days) failed to modify this response. Short and long restraint decreased both the number of lymphocytes and the T-lymphocyte response to Con A stimulation in the peripheral blood. Neither 2 h over 2 days nor 6 h over 4 days modified the splenic lymphoproliferative response to Con A stimulation, but restraint stress progressively decreased the number of mononuclear splenic cells. Both periods of restraint significantly increased plasma concentration of corticosterone, however plasma prolactin levels were significantly lower after 4 days of restraint but not after short restraint (2 h over 2 days). These results indicate that although some immune functions can be increased after acute or short stress, long stress has an immunosuppressive effect, above all on the cellular immunity which is more susceptible to this effect than the humoral response.

Enhancement of tumor growth by drugs with some common molecular actions

A group of structurally related drugs representing diverse therapeutic classes share, among a number of pharmacological properties, enhancement of tumor growth in several rodent models of malignancy. One common action, the inhibition of histamine binding to and catalytic activity of cytochrome P450 monooxygenases, is highly correlated with potency to enhance tumor growth. Among members of this drug ensemble, the antiestrogen tamoxifen has been shown in controlled clinical studies to increase the incidence of uterine and gastrointestinal cancer and to accelerate the course of gastric cancer, and the tamoxifen analogue clomiphene has been linked to neuroblastoma and the tricyclic group of antidepressants to ovarian cancer. The determination of drug affinities for protein modulators of cell growth, proliferation, and transformation suggests a strategy for identifying at least some classes of chemicals that impart oncologic risks to humans.

Do antidepressants cause, promote, or inhibit cancers?

Do antidepressants cause, promote, or inhibit cancers?

OBJECTIVE

To review all human and experimental studies that examined the association of antidepressants with cancer or the effect of antidepressants on neoplastic growth.

METHODS

A search was conducted of MEDLINE for relevant articles published in English between 1976 and 1993.

RESULTS

Four human studies and nine experimental models were found. The human studies showed a transiently statistically significant positive association between amitriptyline and liver cancer and a negative association with pancreatic cancer; and that the antidepressants amitriptyline, nortriptyline, desipramine, and phenelzine may increase risk of breast cancer. Results of the experimental studies differed depending on which antidepressants were examined and which model was used. Amitriptyline was found to promote tumour growth, fluoxetine and clomipramine were reported to be both tumour promoters and antineoplastic agents, and imipramine and citalopram both demonstrated antineoplastic properties.

CONCLUSIONS

Further epidemiologic studies in humans are needed to determine which antidepressants cause, promote, or inhibit cancers.

Chronic restraint attenuates the immunosuppressive response induced by novel aversive stimuli

The exposure to a novel aversive event, such as foot shock, induced a decrease in the percentage of T lymphocytes and a clear reduction in the delayed-type hypersensitivity reaction (DTH). This immunosuppressive response to an acute stressor was absent in rats that were previously exposed to a chronic immobilization stress regime (2 h daily during 7 consecutive days), but was still present in animals with prior exposure to only one or three restraint sessions. No stress effect was observed in other immunologic parameters, such as the percentage of B lymphocytes or the hemagglutinin titer, in any of the experimental treatments. The possible involvement of central adaptive mechanisms in the attenuation of the immunosuppressive response induced by an acute stress is discussed.

Seven-day variable-stress regime alters cortical beta-adrenoceptor binding and immunologic responses: reversal by imipramine

Rats were submitted daily to a variable stressor for 1 week with or without concurrent imipramine (IMI) administration. One day after the last injection or stressful event, binding of cortical beta-adrenoceptors was determined in all experimental groups. Another group of chronically stressed animals with or without concurrent IMI administration were sacrificed 24 h following the last stress or injection treatment, and several immunologic parameters were evaluated. Chronically stressed rats showed an enhanced number of cortical beta-adrenergic sites without changes in their affinity. This effect was not present following concurrent administration with the antidepressant. In addition, a decreased percentage of T lymphocytes and a reduced delayed-type hypersensitivity reaction was also observed in stressed animals. Both responses were no longer evident when stressed rats were previously administered IMI. A possible link between behavioral, neurochemical, and immunologic alterations due to the stress regime is discussed.