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Biomedical subjects

Andrew H Miller

Publications and source records attributed to Andrew H Miller.

At least 19 recordsLinked to original sources
PubMed2006

Cytokine-effects on glucocorticoid receptor function: relevance to glucocorticoid resistance and the pathophysiology and treatment of major depression.

Glucocorticoids play an essential role in the response to environmental stressors, serving initially to mobilize bodily responses to challenge and ultimately serving to restrain neuroendocrine and immune reactions. A number of diseases including autoimmune, infectious and inflammatory disorders as well as certain neuropsychiatric disorders such as major depression have been associated with decreased responsiveness to glucocorticoids (glucocorticoid resistance), which is believed to be related in part to impaired functioning of the glucocorticoid receptor (GR). Glucocorticoid resistance, in turn, may contribute to excessive inflammation as well as hyperactivity of corticotropin releasing hormone and sympathetic nervous system pathways, which are known to contribute to a variety of diseases as well as behavioral alterations. Recent data indicate that glucocorticoid resistance may be a result of impaired GR function secondary to chronic exposure to inflammatory cytokines as may occur during chronic medical illness or chronic stress. Indeed, inflammatory cytokines and their signaling pathways including mitogen-activated protein kinases, nuclear factor-kappaB, signal transducers and activators of transcription, and cyclooxygenase have been found to inhibit GR function. Mechanisms include disruption of GR translocation and/or GR-DNA binding through protein-protein interactions of inflammatory mediators with the GR itself or relevant steroid receptor cofactors as well as alterations in GR phosphorylation status. Interestingly, cAMP signal transduction pathways can enhance GR function and inhibit cytokine signaling. Certain antidepressants have similar effects. Thus, further understanding the effects of cytokines on GR signaling and the mechanisms involved may reveal novel therapeutic targets for reversal of glucocorticoid resistance and restoration of glucocorticoid-mediated inhibition of relevant bodily/immune responses during stress and immune challenge.

Cytokines↗
PubMed2006

Efficacy of risperidone versus olanzapine in patients with schizophrenia previously on chronic conventional antipsychotic therapy: a switch study.

The objective of the study was to examine whether patients with schizophrenia who were judged to be stable on long-term treatment with conventional antipsychotic medications would further benefit from a switch to an atypical antipsychotic drug. Thirty-six subjects with schizophrenia spectrum disorder, on conventional antipsychotic medication therapy for at least 2 years, were randomized in double-blind fashion to risperidone versus olanzapine. Patients were titrated up to 6 mg risperidone or 15 mg olanzapine as tolerated, followed by tapering and discontinuation of conventional antipsychotic medication. Atypical antipsychotic agents were then administered alone (monotherapy) for 12 weeks. Efficacy and tolerability were assessed using the Positive and Negative Syndrome Scale (PANSS), Clinical Global Impression Scale, and Simpson Angus Scale. Body weight was measured at each visit. Both treatment groups exhibited marked and similar improvement in the total PANSS score from baseline to study endpoint (22 weeks) [risperidone: baseline=59.3 (SE 3.1), 22 weeks=44.3 (SE 2.3) (p<0.001); olanzapine: baseline=55.9 (SE 3.3), 22 weeks=46.9 (SE 3.2) (p<0.001). Both groups also exhibited significant reductions in PANSS factor scores for positive and negative symptoms and disorganized thoughts. Only risperidone-treated patients exhibited significant decreases in uncontrolled hostility/excitement and anxiety and depression. Of note, while positive factor scores exhibited the majority of change within the first 10 weeks, negative factor scores continued to decline significantly in both treatment groups throughout the study. Tolerability assessments did not differ between groups. The results indicate that both atypical antipsychotic medications provided significant additional improvement in symptom severity in patients with schizophrenia previously on conventional antipsychotic agents.

Adult↗
PubMed2006

Cognitive dysfunction relates to subjective report of mental fatigue in patients with chronic fatigue syndrome.

Patients with chronic fatigue syndrome (CFS) frequently complain of cognitive dysfunction. However, evidence of cognitive impairment in CFS patients has been found in some, but not other, studies. This heterogeneity in findings may stem from the relative presence of mental fatigue in the patient populations examined. The present study assessed this possibility in a population-based sample of CFS patients. In all, 43 patients with CFS defined by the criteria of the 1994 research case definition using measurements recommended by the 2003 International CFS Study Group, and 53 age-, sex-, and race/ethnicity-matched nonfatigued subjects were included in the study. Mental fatigue was assessed using the mental fatigue subscale of the multidimensional fatigue inventory. Cognitive function was evaluated using an automated battery of computerized tests (Cambridge neuropsychological test automated battery (CANTAB)) that assessed psychomotor function, planning and problem-solving abilities, and memory and attentional performance. CFS patients with significant complaints of mental fatigue (score of mental fatigue 2 standard deviations above the mean of nonfatigued subjects) exhibited significant impairment in the spatial working memory and sustained attention (rapid visual information processing) tasks when compared to CFS patients with low complaints of mental fatigue and nonfatigued subjects. In CFS patients with significant mental fatigue, sustained attention performance was impaired only in the final stages of the test, indicating greater cognitive fatigability in these patients. CFS patients with low mental fatigue displayed performance comparable to nonfatigued subjects on all tests of the CANTAB battery. These findings show strong concordance between subjective complaints of mental fatigue and objective measurement of cognitive impairment in CFS patients and suggest that mental fatigue is an important component of CFS-related cognitive dysfunction.

Cognition Disorders↗
PubMed2006

Increased stress-induced inflammatory responses in male patients with major depression and increased early life stress.

OBJECTIVE: The authors sought to determine innate immune system activation following psychosocial stress in patients with major depression and increased early life stress. METHOD: Plasma interleukin (IL)-6, lymphocyte subsets, and DNA binding of nuclear factor (NF)-kB in peripheral blood mononuclear cells were compared in medically healthy male subjects with current major depression and increased early life stress (N=14) versus nondepressed male comparison subjects (N=14) before and after completion of the Trier Social Stress Test. RESULTS: Trier Social Stress Test-induced increases in IL-6 and NF-kappaB DNA-binding were greater in major depression patients with increased early life stress and independently correlated with depression severity, but not early life stress. Natural killer (NK) cell percentages also increased following stress. However, there were no differences between groups and no correlation between NK cell percentage and stress-induced NF-kappaB DNA-binding or IL-6. CONCLUSIONS: Male major depression patients with increased early life stress exhibit enhanced inflammatory responsiveness to psychosocial stress, providing preliminary indication of a link between major depression, early life stress and adverse health outcomes in diseases associated with inflammation.

Adult↗
PubMed2005

Cytokines sing the blues: inflammation and the pathogenesis of depression.

Increasing amounts of data suggest that inflammatory responses have an important role in the pathophysiology of depression. Depressed patients have been found to have higher levels of proinflammatory cytokines, acute phase proteins, chemokines and cellular adhesion molecules. In addition, therapeutic administration of the cytokine interferon-alpha leads to depression in up to 50% of patients. Moreover, proinflammatory cytokines have been found to interact with many of the pathophysiological domains that characterize depression, including neurotransmitter metabolism, neuroendocrine function, synaptic plasticity and behavior. Stress, which can precipitate depression, can also promote inflammatory responses through effects on sympathetic and parasympathetic nervous system pathways. Finally, depression might be a behavioral byproduct of early adaptive advantages conferred by genes that promote inflammation. These findings suggest that targeting proinflammatory cytokines and their signaling pathways might represent a novel strategy to treat depression.

Animals↗
PubMed2005

Anterior cingulate activation and error processing during interferon-alpha treatment.

BACKGROUND: There has been increasing interest in the role of immunologic processes, notably cytokines, in the development of behavioral alterations, especially in medically ill patients. Interferon (IFN)-alpha is notorious for causing behavioral symptoms, including depression, fatigue, and cognitive dysfunction, and has been used to investigate the effects of cytokines on the brain. METHODS: In the present study we assessed the effects of low-dose IFN-alpha on brain activity, using functional magnetic resonance imaging during a task of visuospatial attention in patients infected with hepatitis C virus (HCV). RESULTS: Despite endorsing symptoms of impaired concentration and fatigue, IFN-alpha-treated patients (n = 10) exhibited task performance and activation of parietal and occipital brain regions similar to that seen in HCV-infected control subjects (n = 11). Interestingly, however, in contrast to control subjects, IFN-alpha-treated patients exhibited significant activation in the dorsal part of the anterior cingulate cortex (ACC), which highly correlated with the number of task-related errors. No such correlation was found in control subjects. CONCLUSIONS: Consistent with the role of the ACC in conflict monitoring, ACC activation during IFN-alpha administration suggests that cytokines might increase processing conflict or reduce the threshold for conflict detection, thereby signaling the need to exert greater mental effort to maintain performance. Such alterations in ACC activity might in turn contribute to cytokine-induced behavioral changes.

Adult↗
PubMed2005

Mood disorders in the medically ill: scientific review and recommendations.

OBJECTIVE: The purpose of this review is to assess the relationship between mood disorders and development, course, and associated morbidity and mortality of selected medical illnesses, review evidence for treatment, and determine needs in clinical practice and research. DATA SOURCES: Data were culled from the 2002 Depression and Bipolar Support Alliance Conference proceedings and a literature review addressing prevalence, risk factors, diagnosis, and treatment. This review also considered the experience of primary and specialty care providers, policy analysts, and patient advocates. The review and recommendations reflect the expert opinion of the authors. STUDY SELECTION/DATA EXTRACTION: Reviews of epidemiology and mechanistic studies were included, as were open-label and randomized, controlled trials on treatment of depression in patients with medical comorbidities. Data on study design, population, and results were extracted for review of evidence that includes tables of prevalence and pharmacological treatment. The effect of depression and bipolar disorder on selected medical comorbidities was assessed, and recommendations for practice, research, and policy were developed. CONCLUSIONS: A growing body of evidence suggests that biological mechanisms underlie a bidirectional link between mood disorders and many medical illnesses. In addition, there is evidence to suggest that mood disorders affect the course of medical illnesses. Further prospective studies are warranted.

Acquired Immunodeficiency Syndrome↗
PubMed2005

Promoter polymorphisms of the interferon-alpha receptor gene and development of Interferon-induced depressive symptoms in patients with chronic hepatitis C: preliminary findings.

BACKGROUND: Interferon (IFN)-alpha treatment frequently induces depression, which can impair quality of life and reduce treatment adherence. Defining relevant risk factors for IFN-alpha-induced depression is essential for designing preventative treatment strategies. OBJECTIVE: The purpose of the present study was to determine whether promoter polymorphisms of -408C/T, -3C/T and GT repeat dinucleotide microsatellite in the IFN-alpha/beta receptor 1 (IFNAR1) gene are associated with the development of IFN-induced depression. METHOD: Fifty patients with chronic hepatitis C were treated with pegylated IFN alpha-2b plus a standard or weight-based dose of ribavirin. Severity of depression was assessed using the Zung Self-Rating Depression Scale (SDS) at baseline and at 4, 8, 12 and 24 weeks of treatment. RESULT: The baseline to maximum difference in the SDS index score of neurovegetative/somatic symptoms was higher in patients with the 5/14 genotype of the GT repeat dinucleotide microsatellite polymorphism than in those patients with other genotypes (p = 0.0084). CONCLUSION: This preliminary result suggests that the promoter GT repeat dinucleotide microsatellite polymorphism of the IFNAR1 gene may represent a risk factor for the development of depressive symptoms during IFN-alpha therapy for hepatitis C and other conditions.

Adult↗
PubMed2005

Depressive symptoms and viral clearance in patients receiving interferon-alpha and ribavirin for hepatitis C.

Interferon (IFN)-alpha plus ribavirin is an effective treatment for hepatitis C virus (HCV) infection, but is associated with a high rate of depression. Depression has been linked to a worse outcome in multiple medical disorders including viral illnesses. We examined whether increased symptoms of depression during IFN-alpha/ribavirin therapy were associated with a reduced treatment response as assessed by clearance of HCV. Depressive symptoms were evaluated in 102 HCV-infected patients at baseline and after 4, 8, 12, and 24 weeks of pegylated IFN-alpha-2b plus ribavirin therapy using the Zung self-rating depression scale (SDS). Viral clearance was determined at 24 weeks by polymerase chain reaction (PCR). Only 34% of subjects (10 out of 29) with a 20-point or greater increase in SDS Index score were HCV PCR negative at 24 weeks, compared to 59% (24 out of 41) of patients with a 10-19 point increase in SDS Index and 69% (22 out of 32) of patients with a less than 10 point increase (chi2=7.6, df=2, p <0.05). In addition, a 20-point or greater increase in SDS Index score during IFN-alpha/ribavirin therapy significantly predicted failure to clear virus when considered alone [crude odds ratio (OR), 3.2; 95% confidence interval (CI), 1.3-8.0; p <0.01] or when controlling for other factors that affected IFN-alpha treatment response (adjusted OR, 3.6; 95% CI, 1.3-9.5; p=0.01). These preliminary findings suggest that individuals who experience significant increases in depressive symptoms during IFN-alpha/ribavirin therapy may be less likely to clear virus, highlighting the importance of identifying and treating depressive symptoms in this patient population.

Adult↗
PubMed2005

Inhibition of Jun N-terminal kinase (JNK) enhances glucocorticoid receptor-mediated function in mouse hippocampal HT22 cells.

Mitogen-activated protein kinases (MAPKs), including Jun N-terminal kinase (JNK), promote inflammatory and proliferative responses to infection and other environmental stimuli including stress. Relevant to negative regulation of inflammatory pathways by glucocorticoids and the development of glucocorticoid resistance (observed in inflammatory disorders as well as certain neuropsychiatric disorders such as major depression), activation of JNK has been reported to inhibit glucocorticoid receptor (GR) function. In this study, the role of JNK pathways in modulating GR function was further investigated. Treatment of mouse hippocampal (HT22) cells with the selective JNK inhibitor, SP-600125 (0.1-10 microM), resulted in dose-dependent induction of GR-mediated MMTV-luciferase activity. SP-600125 also significantly enhanced dexamethasone-induced MMTV-luciferase activity, while increasing GR binding to the glucocorticoid responsive element, both in the presence and absence of Dex. Similar effects were observed in mouse fibroblast cells (LMCAT), and in HT22 cells treated with a JNK specific antisense oligonucleotide. The induction of GR-mediated function by SP-600125 was not due to altered cytosolic GR binding or GR protein expression or enhancement of GR nuclear translocation as determined by Western blot. Taken together, the data indicate that constitutive expression of JNK plays a tonic inhibitory role in GR function, which is consistent with findings that activation of JNK pathways inhibits GR. The data also identify potential pathways involved in the pathogenesis of the glucocorticoid resistance found in certain chronic immune/inflammatory diseases and subgroups of patients with major depression. Moreover, JNK pathways may represent a therapeutic target for normalization of GR function in these disorders.

Animals↗
PubMed2005

Immune modulation of the hypothalamic-pituitary-adrenal (HPA) axis during viral infection.

Compelling data has been amassed indicating that soluble factors, or cytokines, emanating from the immune system can have profound effects on the neuroendocrine system, in particular the hypothalamic- pituitary-adrenal (HPA) axis. HPA activation by cytokines (via the release of glucocorticoids), in turn, has been found to play a critical role in restraining and shaping immune responses. Thus, cytokine-HPA interactions represent a fundamental consideration regarding the maintenance of homeostasis and the development of disease during viral infection. Although reviews exist that focus on the bi-directional communication between the immune system and the HPA axis during viral infection (188,235), others have focused on the immunomodulatory effects of glucocorticoids during viral infection (14,225). This review, however, concentrates on the other side of the bi-directional loop of neuroendocrine-immune interactions, namely, the characterization of HPA axis activity during viral infection and the mechanisms employed by cytokines to stimulate glucocorticoid release.

Adrenocorticotropic Hormone↗
PubMed2005

Neuropsychiatric adverse effects of interferon-alpha: recognition and management.

Recombinant preparations of the cytokine interferon (IFN)-alpha are increasingly used to treat a number of medical conditions, including chronic viral hepatitis and several malignancies. Although frequently effective, IFN alpha induces a variety of neuropsychiatric adverse effects, including an acute confusional state that develops rapidly after initiation of high-dose IFN alpha, a depressive syndrome that develops more slowly over weeks to months of treatment, and manic conditions most often characterised by extreme irritability and agitation, but also occasionally by euphoria. Acute IFN alpha-induced confusional states are typically characterised by disorientation, lethargy, somnolence, psychomotor retardation, difficulties with speaking and writing, parkinsonism and psychotic symptoms. Strategies for managing delirium should be employed, including treatment of contributing medical conditions, use of either typical or atypical antipsychotic agents and avoidance of medications likely to worsen mental status. Significant depressive symptoms occur in 21-58% of patients receiving IFN alpha, with symptoms typically manifesting over the first several months of treatment. The most replicated risk factor for developing depression is the presence of mood and anxiety symptoms prior to treatment. Other potential, but less frequently replicated, risk factors include a past history of major depression, being female and increasing IFN alpha dosage and treatment duration. The available data support two approaches to the pharmacological management of IFN alpha-induced depression: antidepressant pretreatment or symptomatic treatment once IFN alpha has been initiated. Pretreatment might be best reserved for patients already receiving antidepressants or for patients who endorse depression or anxiety symptoms of mild or greater severity prior to therapy. Several recent studies demonstrate that antidepressants effectively treat IFN alpha-induced depression once it has developed, allowing the vast majority of subjects to complete treatment successfully. Recent data suggest that IFN alpha-induced depression may be composed of two overlapping syndromes: a depression-specific syndrome characterised by mood, anxiety and cognitive complaints, and a neurovegetative syndrome characterised by fatigue, anorexia, pain and psychomotor slowing. Depression-specific symptoms are highly responsive to serotonergic antidepressants, whereas neurovegetative symptoms are significantly less responsive to these agents. These symptoms may be more effectively treated by agents that modulate catecholaminergic functioning, such as combined serotonin-noradrenaline (norepinephrine) antidepressants, bupropion, psychostimulants or modafinil. Additional factors to consider in selecting an antidepressant include potential drug-drug interactions and adverse effect profile. Finally, IFN alpha appears capable of inducing manic symptoms. Mania, especially when severe, is a clinical emergency. When this occurs, IFN alpha and antidepressants should be stopped, an emergency psychiatric consultation should be obtained, and treatment with a mood stabilizer should be initiated.

Antiviral Agents↗
PubMed2005

Depression during pegylated interferon-alpha plus ribavirin therapy: prevalence and prediction.

BACKGROUND: Interferon-alpha (IFN-alpha) plus ribavirin is used to treat hepatitis C virus (HCV) infection and is associated with a high rate of depression. Newer, pegylated preparations of IFN-alpha have a longer half-life, require once-per-week dosing, and may be associated with reduced neuropsychiatric burden. Limited data exist on depression during pegylated IFN-alpha therapy. METHOD: Depressive symptoms were assessed using the Zung Self-Rating Depression Scale (SDS) in 162 HCV-infected patients at baseline and after 4, 8, 12, and 24 weeks of treatment with pegylated IFN alpha-2b (PEG IFN) plus weight-based (N = 86) versus standard dose (N = 76) ribavirin. Data were collected from March 2001 to April 2003. RESULTS: Compared with baseline, mean SDS index scores were significantly increased by week 4 and remained elevated throughout the study. Thirty-nine percent of the sample experienced moderate to severe depressive symptoms (SDS index score > or = 60) at some point during PEG IFN/ribavirin therapy. Baseline depression scores significantly predicted severity of depressive symptoms during PEG IFN/ribavirin treatment (simple regression analysis: Y = 0.55X + 32.7, p < .0001). In addition, assignment to weight-based ribavirin treatment and history of depression were associated with increased likelihood of developing moderate to severe depressive symptoms (odds ratio [OR] = 2.7, 95% CI = 1.3 to 5.6, p < .01, and OR = 3.3, 95% CI = 1.3 to 8.1, p < .01, respectively). CONCLUSIONS: Development of moderate to severe depressive symptoms occurred frequently during PEG IFN/ribavirin treatment and was predicted by baseline depression scores and higher doses of ribavirin. History of major depressive disorder was also a significant predictive factor, but only through association with elevated baseline depression status. All of these factors can be evaluated and addressed to limit neuropsychiatric morbidity during HCV treatment.

Administration, Buccal↗
PubMed2004

Cytokines and psychopathology: lessons from interferon-alpha.

Interferon-alpha is a potent inducer of the cytokine network and is notorious for causing behavioral alterations. Studies on interferon-alpha-treated patients reveal at least two distinct syndromes: 1) a mood/cognitive syndrome that appears late during interferon-alpha therapy is responsive to antidepressants and is associated with activation of neuroendocrine pathways and altered serotonin metabolism; and 2) a neurovegetative syndrome characterized by psychomotor slowing, and fatigue that appears early during interferon-alpha treatment is antidepressant nonresponsive and may be mediated by alterations in basal ganglia dopamine metabolism. Findings from interferon-alpha may provide important clues regarding the pathophysiology and treatment of cytokine-induced behavioral changes in medically ill patients, while also potentially modeling the development of neuropsychiatric symptoms in patients without medical disorders.

Adrenocorticotropic Hormone↗
PubMed2004

Early life stress and PTSD symptoms in patients with comorbid schizophrenia and substance abuse.

OBJECTIVE: The comorbidity of schizophrenia and substance abuse is well documented and is remarkable for its prevalence and poor prognosis. While the etiology for this association is unknown, one possible mechanism relates to traumatic early life experiences, which have been shown to predispose individuals to both psychosis and substance abuse. METHODS: Participants (N=122) who were outpatients in an inner city public mental health clinic and who were diagnosed with schizophrenia, were administered a battery of structured clinical assessments including the Childhood Traumatic Events Scale (CTES), Davidson PTSD rating scale, Hamilton Depression Rating Scale (HDRS), Positive and Negative Symptom Scale (PANSS), and assessments of medication satisfaction and side effects. Patients with schizophrenia and a history of substance abuse (N=70) were compared to patients with schizophrenia who did not have a history of substance abuse (N=52). RESULTS: Patients with schizophrenia and a history of substance abuse had significantly higher frequency and severity of childhood traumatic events, greater PTSD symptomatology, significantly higher depression scores, and higher scores on the general subscale of the PANSS. DISCUSSION: Our findings lend support to the notion that sensitization to stress from early life experiences may be a factor contributing to the high rate of substance abuse comorbidity in patients with schizophrenia.

Adult↗
PubMed2004

Characterization of an interleukin-6- and adrenocorticotropin-dependent, immune-to-adrenal pathway during viral infection.

There has been longstanding interest in the capacity of the immune system to access immunomodulatory glucocorticoid responses without invoking upstream neuroendocrine secretagogues, including CRH and ACTH. Here, we investigate the role of CRH and ACTH in adrenal glucocorticoid responses to murine cytomegalovirus (MCMV). Mice infected with MCMV exhibit IL-6-dependent glucocorticoid responses that peak at 36 h post infection and protect against cytokine (TNFalpha)-mediated lethality. Acute administration of a CRH-antibody (Ab) completely eliminated ACTH responses to both low- and high-dose MCMV. However, corticosterone responses in CRH-Ab-treated animals remained apparent in mice infected with low-dose MCMV and were robust in mice infected with high-dose MCMV. CRH-knockout (KO) mice exhibited robust corticosterone responses to both MCMV doses, despite reduced baseline and MCMV-induced ACTH. Interestingly, robust corticosterone responses in CRH-Ab-treated and CRH-KO mice were associated with exaggerated IL-6 levels, and IL-6 and corticosterone concentrations in infected CRH-Ab-treated animals were significantly correlated. Neutralization of IL-6 responses in infected CRH-KO mice reduced corticosterone responses by approximately 70%. Finally, MCMV-infected mice deprived of ACTH by hypophysectomy failed to elicit glucocorticoid responses, despite elevated plasma IL-6 concentrations. Taken together, these results suggest that a greater than normal induction of IL-6 compensates for the absence of a normal CRH-dependent ACTH surge during viral infection. This enhanced IL-6 response, in turn, may mediate a direct immune-adrenal pathway that can become a predominant driving force for glucocorticoid induction in the absence of CRH. However, the presence of ACTH appears to serve as a necessary permissive factor, enabling direct cytokine actions on the adrenal gland.

Adrenocorticotropic Hormone↗