The novel antidepressant ketamine enhances dentate gyrus proliferation with no effects on synaptic plasticity or hippocampal function in depressive-like rats.

AIM: Major depressive disorder is a common and debilitating condition with substantial economic impact. Treatment options, although effective, are aimed at relieving the symptoms with limited disease modification. Ketamine, a commonly used anaesthetic, has received substantial attention as it shows rapid antidepressant effects clinically. We studied the effects of ketamine on hippocampal function and dentate gyrus proliferation in rats showing a depressive-like phenotype. METHODS: Adolescent and adult animals were pre-natally exposed to the glucocorticoid analog dexamethasone, and we verified a depressive-like phenotype using behavioural tests, such as the sucrose preference. We subsequently studied the effects of ketamine on hippocampal synaptic transmission, plasticity and dentate gyrus proliferation. In addition, we measured hippocampal glutamate receptor expression. We also tested the ketamine metabolite hydroxynorketamine for NMDA-receptor independent effects. RESULTS: Surprisingly, our extensive experimental survey revealed limited effects of ketamine or its metabolite on hippocampal function in control as well as depressive-like animals. We found no effects on synaptic efficacy or induction of long-term potentiation in adolescent and adult animals. Also there was no difference when comparing the dorsal and ventral hippocampus. Importantly, however, ketamine 24 hours prior to experimentation significantly increased the dentate gyrus proliferation, as revealed by Ki-67 immunostaining, in the depressive-like phenotype. CONCLUSION: We find limited effects of ketamine on hippocampal glutamatergic transmission. Instead, alterations in dentate gyrus proliferation could explain the antidepressant effects of ketamine.

Targeting the Endocannabinoid/CB1 Receptor System For Treating Major Depression Through Antidepressant Activities of Curcumin and Dexanabinol-Loaded Solid Lipid Nanoparticles.

BACKGROUND/AIMS: This study investigated the underlying mechanisms of the antidepressant effects of curcumin and dexanabinol-loaded solid lipid nanoparticles in corticosterone-induced cell and mice depression models. METHODS: Curcumin and dexanabinol-loaded solid lipid nanoparticles (Cur/SLNs-HU-211) were synthesized via an emulsifcation and low-temperature solidification method. Antidepressant activities of nanoparticles in a corticosterone-induced major depression model were investigated by MTT assay, cellular uptake by flow cytometry, behaviour by Forced Swimming Test and rotarod test, neurotransmitters by High Performance Liquid Chromatography, Western blotting, qPCR and immunofluorescence. RESULTS: Treatment with Cur/SLNs-HU-211 induced greater dopamine (DA)/5-hydroxytryptamine (5-HT) release with reduced corticosterone-induced apoptotic cell death in PC12 cells. Additionally, in vivo Cur/SLNs-HU-211 significantly induced recovery from depressive behaviour with increased DA/5-HT levels, CB1 mRNA levels and CB1, p-MEK1 and p-ERK1/2 protein expression levels in the hippocampus and striatum. Cur/SLNs-HU-211 improved CB1 expression and inspired the proliferation of astrocytes in the hippocampus and striatum, exerted neuroprotective effects by preventing corticosterone -induced BDNF/NeuN expression reduction. CONCLUSION: Our study implies that Cur/SLNs-HU-211 may be a useful approach for treatment of major depression.

2, 3, 5, 4'-Tetrahydroxystilbene-2-O-ß-D-glucoside prevention of lipopolysaccharide-induced depressive-like behaviors in mice involves neuroinflammation and oxido-nitrosative stress inhibition.

Although numerous hypotheses have been raised in recent years, the exact mechanisms that promote the development of major depression are largely unknown. Recently, strategies targeting the process of neuroinflammation and oxidative stress in depression have been attracting greater attention. 2, 3, 5, 4'-Tetrahydroxystilbene-2-O-ß-D-glucoside (TSG), a compound purified from a traditional Chinese herbal medicine polygonummultiflorum, has been widely reported to inhibit neuroinflammation and oxidative stress. In this context, we investigated whether TSG affects lipopolysaccharide (LPS)-induced depressive-like behaviors in a manner associated with neuroinflammation and oxido-nitrosative stress. Results showed that administration of ICR mice with 0.83 mg/kg of LPS-induced typical depressive-like behaviors in the experiments of the tail-suspension test, the forced-swimming test, and sucrose preference, and these behaviors were prevented by TSG treatment (30 and 60 mg/kg). Further analysis showed that TSG pretreatment at the doses of 30 and 60 mg/kg not only inhibited the production of proinflammatory cytokines induced by LPS, such as interleukin-1ß, interleukin-6, and tumor necrosis factor-α, but also prevented the LPS-induced enhancement of oxido-nitrosative stress in mouse hippocampus and prefrontal cortex. The LPS-induced decreases in brain-derived neurotrophic factor levels in the hippocampus and prefrontal cortex were also prevented by TSG treatment. Generally, our data provide evidence to show that TSG could be used to cope with depressive-like symptoms by inhibition of neuroinflammation and oxido-nitrosative stress.

Higher DHEA-S (dehydroepiandrosterone sulfate) levels are associated with depressive symptoms during the menopausal transition: results from the PENN Ovarian Aging Study.

The influence of sex hormones on mood during the menopausal transition has been the subject of ongoing investigation. Because dehydroepiandrosterone sulfate (DHEA-S) has been associated with several indicators of healthy aging, we conducted a population-based study of midlife women to determine the relationship between DHEA-S levels and depressive symptoms and major depression during the transition through menopause. Unexpectedly, the original report revealed a positive correlation between DHEA-S levels and depressive symptoms at baseline. The cohort was studied over 11 years to determine whether the positive association between DHEA-S levels and depression persists through the menopausal transition. We conducted a longitudinal cohort study with 11 assessments during an 11-year interval in Philadelphia, Pennsylvania, using a randomly identified, population-based sample of 436 African American and Caucasian premenopausal women aged 35 to 47 years at enrollment. For outcome measures, we used the Center for Epidemiologic Studies Depression Scale and standardized diagnosis of major depression. In a multivariable model, DHEA-S levels were positively associated with depressive symptoms when adjusted for age, menopausal stage, race, smoking status, and body mass index. There was no association between DHEA-S levels and a diagnosis of major depression. DHEA-S levels were positively associated with depressive symptoms through the menopausal transition. No association with major depression was apparent during the menopausal transition, but results may have limited power due to low prevalence of major depression in this cohort. These findings suggest that taking DHEA supplements may increase depressive symptoms for some women, and women and their physicians should be cautious about instituting DHEA replacement therapy during the menopausal transition.

Changes in allergy symptoms and depression scores are positively correlated in patients with recurrent mood disorders exposed to seasonal peaks in aeroallergens.

Although growing evidence supports an association between allergy, allergens and depression, it remains unknown if this relationship is between "states" (possible triggers) or "traits" (possible vulnerabilities). We hypothesized that patients with recurrent mood disorders who are sensitized to tree pollen (as determined by allergen specific IgE antibodies), in comparison to those who are not sensitized, would report larger negative changes in mood during exposure to tree pollen in spring. We also hypothesized that differences between high and low tree pollen periods in self reported allergy symptoms would correlate positively with differences in self reported depression scores. We present 1-year preliminary data on the first 51 patients with unipolar or bipolar disorder (age: 19-63 years, 65% female, twelve patients were tree-pollen IgE positive). Ratings of mood and allergic disease status were performed once during the peak airborne pollen counts and once during the period of low airborne pollen counts, as reported by two local pollen counting stations. Linear regression models were developed to examine associations of changes in depression scores (dependent variable) with tree pollen sensitization, changes in the allergy symptom severity score, adjusted for gender and order of testing. We did not confirm the hypothesized relationship between a specific tree pollen sensitization and changes in mood during tree pollen exposure. We did confirm the hypothesized positive relationship between the changes in allergy symptoms and changes in subjects' depression scores (adjusted p<0.05). This result is consistent with previous epidemiological evidence connecting allergy with depression, as well as our recent reports of increased expression of cytokines in the prefrontal cortex in victims of suicide and in experimental animals sensitized and exposed to tree pollen. A relationship between changes in allergy symptom scores and changes in depression scores supports a state-level rather than only trait-level relationship, and thus lends optimism to future causality-testing interventional studies, which might then lead to novel preventative environmental interventions in mood disorders.

The art of prescribing. Antidepressants in late-life depression: prescribing principles.

QUESTION: Ms. Antai-Otong, I am a psychiatric nurse practitioner currently employed in a large primary care clinic. My greatest challenge with older adults suspected of being depressed is their hesitancy to admit they are depressed or unwillingness to take antidepressants. I have started some of these patients on antidepressants and had mixed results. Please provide some guidelines for treating depression in older adults with coexisting medical conditions. ANSWER: Depression is a common companion of chronic medical illnesses and frequently goes unrecognized and untreated, resulting in high morbidity and mortality. Depression is unrecognized and underdiagnosed in approximately 16% of older patients seen in primary care settings (Unutzer, 2002). Typically, older adults deny being depressed, minimize symptom severity, fail to recognize common subjective experiences, such as anhedonia, fatigue, and concentration difficulties associated with this disorder, and hesitate to accept their illness due to social stigma and effects of stoicism. Cultural and generational influences also impact how older adults perceive mental health services. Due to the growing number of individuals 65 and older with coexisting medical and psychiatric conditions, particularly depression, seeking health care in vast practice settings, advanced practice psychiatric nurses must collaborate with primary care providers and develop holistic care that addresses coexisting chronic medical and psychiatric conditions.

Baseline immune activation as a risk factor for the onset of depression during interferon-alpha treatment.

BACKGROUND: Major depression has been associated cross-sectionally with increased cell-mediated immune activation but causality has been difficult to establish. This study prospectively investigated the hypothesis that baseline level of immune activation predicts the development of depression during interferon-alpha (IFN-alpha) treatment. METHODS: Sixteen hepatitis C patients without psychiatric disorder underwent IFN-alpha treatment. Proinflammatory and anti-inflammatory cytokines were determined before starting treatment. Presence of a major depressive disorder (MDD) was assessed at baseline and several times during treatment. RESULTS: Baseline soluble interleukin-2 receptor (sIL-2r), interleukin-6 (IL-6), and interleukin-10 (IL-10) concentrations were significantly increased in the five subjects that developed MDD during treatment compared with those that did not, with standardized effect sizes of 1.08, 1.16, and 1.25, respectively, controlling for marijuana use, cigarette smoking, and baseline level of depressive symptoms. CONCLUSIONS: Results suggest that increased immune activation, rather than an epiphenomenon, is a causal risk factor for the development of MDD.

Cytokines and major depression.

In the research field of psychoneuroimmunology, accumulating evidence has indicated the existence of reciprocal communication pathways between nervous, endocrine and immune systems. In this respect, there has been increasing interest in the putative involvement of the immune system in psychiatric disorders. In the present review, the role of proinflammatory cytokines, such as interleukin (IL)-1, tumour necrosis factor (TNF)-alpha and interferon (IFN)-gamma, in the aetiology and pathophysiology of major depression, is discussed. The 'cytokine hypothesis of depression' implies that proinflammatory cytokines, acting as neuromodulators, represent the key factor in the (central) mediation of the behavioural, neuroendocrine and neurochemical features of depressive disorders. This view is supported by various findings. Several medical illnesses, which are characterised by chronic inflammatory responses, e.g. rheumatoid arthritis, have been reported to be accompanied by depression. In addition, administration of proinflammatory cytokines, e.g. in cancer or hepatitis C therapies, has been found to induce depressive symptomatology. Administration of proinflammatory cytokines in animals induces 'sickness behaviour', which is a pattern of behavioural alterations that is very similar to the behavioural symptoms of depression in humans. The central action of cytokines may also account for the hypothalamic-pituitary-adrenal (HPA) axis hyperactivity that is frequently observed in depressive disorders, as proinflammatory cytokines may cause HPA axis hyperactivity by disturbing the negative feedback inhibition of circulating corticosteroids (CSs) on the HPA axis. Concerning the deficiency in serotonergic (5-HT) neurotransmission that is concomitant with major depression, cytokines may reduce 5-HT levels by lowering the availability of its precursor tryptophan (TRP) through activation of the TRP-metabolising enzyme indoleamine-2,3-dioxygenase (IDO). Although the central effects of proinflammatory cytokines appear to be able to account for most of the symptoms occurring in depression, it remains to be established whether cytokines play a causal role in depressive illness or represent epiphenomena without major significance.

Major depressive disorder with psychotic features induced by interferon-alpha treatment for hepatitis C in a polydrug abuser.

Infectious diseases, especially hepatitis C, are prevalent among drug abusers. Interferon-alpha (IFN-alpha) is the pharmacological treatment of choice for this condition. Patients being treated with IFN-alpha can be expected to experience such psychiatric side-effects as development of depression, mania, irritability, changes in personality, hallucinations or delirium. In addition, certain patients are considered to be at greater risk of developing neuropsychiatric side-effects. Individuals meeting the following criteria are particularly vulnerable: over 40 years of age; having central nervous system abnormalities; a previous neurological or psychiatric history; a past familial psychiatric history; use of narcotics or having alcohol or substance use disorders; being HIV-positive; coadministration of other cytokines; receiving high doses of IFN-alpha (> 6 million units). We report the case of a 29-year-old patient with chronic non-active hepatitis C, a previous psychiatric history of polydrug abuse (cannabis, heroin and illegal use of the psychotropic drug biperiden) and anxiety disorder. Two weeks after the initiation of IFN-alpha treatment, he developed fatigue, sleeplessness and persecutory delusions. The patient responded partially to the discontinuation of the IFN-alpha treatment. Due to the presence of three risk factors in this patient, he was considered to belong to the group of patients being 'at high risk' of developing neuropsychiatric side-effects. This is the first case report of major depressive disorder with psychotic features in such a 'high-risk patient'. This case report may prompt other research by showing the importance of the close monitoring, and the prevention of the progression of IFN-alpha-related psychiatric disorders in 'a high-risk patient'.

Evidence-informed assessment and treatment of depression in HCV and interferon-treated patients.

More than 4 million people are currently infected with Hepatitis C an RNA virus that may ultimately result in complete hepatic failure and is often a silent infection until late in the course of disease. Hepatitis C patients have increased rates of major depression (as well as substance abuse) and treatment of hepatitis with interferon, the current standard treatment, provokes episodes of depression in as many as a third of patients treated. Immune-dysfunction mediated mechanisms for the depression in these patients have been proposed and have increasing experimental support. The resulting depression has interfered with treatment for many patients, but several standard treatments for depression have been shown to be effective in patients with interferon-associated depression, suggesting that this should not be a barrier to effective treatment. In this paper, we review the evidence for associations between depression and Hepatitis C and interferon treatment, as well as the evidence supporting an immune mechanism for the association, and finally the data showing effective treatment and recommendations for prophylactic use of anti-depressants.