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Biomedical subjects

Andrew H Miller

Publications and source records attributed to Andrew H Miller.

At least 37 records · Page 2Linked to original sources
PubMed2004

Pituitary-adrenal responses to standard and low-dose dexamethasone suppression tests in adult survivors of child abuse.

BACKGROUND: Previous studies indicate that adverse childhood events are associated with persistent changes in corticotropin-releasing factor neuronal systems. Our aim was to determine whether altered glucocorticoid feedback mediates the neuroendocrine sequelae of childhood trauma. METHODS: Standard and low-dose dexamethasone suppression tests (DST) were performed in women with a history of child abuse (n=19), child abuse and major depression (n=16), major depression and no childhood trauma (n=10), and no history of mental illness or childhood trauma (n=19). Secondary analysis with posttraumatic stress disorder (PTSD) as the organizing diagnosis was also conducted. RESULTS: In the low-dose DST, depressed women with a history of abuse exhibited greater cortisol suppression than any comparator group and greater corticotropin suppression than healthy volunteers or nondepressed abuse survivors. There were no differences between nondepressed abuse survivors and healthy volunteers in the low-dose DST or between any subject groups in the standard DST. The PTSD analysis produced similar results. CONCLUSIONS: Cortisol supersuppression is evident in psychiatrically ill trauma survivors, but not in nondepressed abuse survivors, indicating that enhanced glucocorticoid feedback is not an invariable consequence of childhood trauma but is more related to the resultant psychiatric illness in traumatized individuals.

Adrenal Cortex Hormones↗
PubMed2004

Baseline mood and psychosocial characteristics of patients developing depressive symptoms during interleukin-2 and/or interferon-alpha cancer therapy.

It has been suggested that patients with subclinical mood symptoms prior to initiating cytokine treatment (as revealed by elevated baseline scores on depression rating scales) are more likely to become clinically depressed during the course of cytokine therapy. The present study was designed to identify which specific preexisting symptoms predict development of depressive symptomatology during treatment with the cytokines, interleukin-2 (IL-2) and/or interferon-alpha (IFN-alpha), in patients with cancer. Thirty-two patients with renal cell carcinoma or malignant melanoma eligible to receive treatment with IL-2 and/or IFN-alpha were enrolled in the study. At baseline and after one month of cytokine therapy (endpoint), depressive symptoms were assessed using the clinician-administered Montgomery-Asberg depression rating scale (MADRS). Illness-related coping strategies, social support, somatic complaints, quality of sleep and demographic factors were also assessed as relevant baseline predictive factors. MADRS scores significantly increased during cytokine therapy. Patients with moderate to marked depressive symptomatology at study endpoint exhibited higher baseline scores in dimensions of the MADRS scale assessing emotional (especially reported sadness), cognitive (especially pessimistic thoughts) and neurovegetative (sleep disturbances) symptoms compared to patients who remained free of depressive symptoms during cytokine therapy. Interestingly, only emotional symptoms and sleep disturbance at baseline, along with low social support, predicted severity of depressive symptoms at the end of the first month of therapy. By documenting specific behavioral vulnerability factors for cytokine-induced depressive symptoms, these findings may help identify patients at risk for mood disturbances during cytokine treatment and help target specific patient populations and specific symptoms for preventative strategies.

Adaptation, Psychological↗
PubMed2004

Plasma homocysteine and immune activation in patients with malignant melanoma undergoing treatment with IFN-alpha.

Immune activation and cell proliferation may contribute to the development of increased homocysteine concentrations in patients with malignant diseases. In this study, we investigated the effect of interferon-alpha (IFN-alpha) on plasma homocysteine concentrations in patients being treated for malignant melanoma. In parallel, neopterin formation and tryptophan degradation were monitored to assess the capacity of IFN-alpha to activate macrophages. Plasma concentrations of homocysteine, folate, and vitamin B(12) were determined in 15 patients with malignant melanoma during 12 weeks of high-dose IFN-alpha therapy. Concurrently, concentrations of neopterin, tryptophan, and kynurenine were measured, and the kynurenine/tryptophan ratio (kyn/trp) was calculated. Homocysteine and folate concentrations during treatment with IFN-alpha did not differ from baseline. In contrast, significant increases in neopterin formation and tryptophan degradation were apparent during IFN-alpha therapy. Plasma concentrations of vitamin B(12) and cysteine also increased. These results indicate that IFN-alpha directly activates macrophages to release neopterin and to degrade tryptophan, but obviously treatment with INF-alpha did not affect homocysteine metabolism.

Adult↗
PubMed2004

A cytokine-based neuroimmunologic mechanism of cancer-related symptoms.

While many of the multiple symptoms that cancer patients have are due to the disease, it is increasingly recognized that pain, fatigue, sleep disturbance, cognitive dysfunction and affective symptoms are treatment related, and may lead to treatment delays or premature treatment termination. This symptom burden, a subjective counterpart of tumor burden, causes significant distress. Progress in understanding the mechanisms that underlie these symptoms may lead to new therapies for symptom control. Recently, some of these symptoms have been related to the actions of certain cytokines that produce a constellation of symptoms and behavioral signs when given exogenously to both humans and animals. The cytokine-induced sickness behavior that occurs in animals after the administration of infectious or inflammatory agents or certain proinflammatory cytokines has much in common with the symptoms experienced by cancer patients. Accordingly, we propose that cancer-related symptom clusters share common cytokine-based neuroimmunologic mechanisms. In this review, we provide evidence from clinical and animal studies that correlate the altered cytokine profile with cancer-related symptoms. We also propose that the expression of coexisting symptoms is linked to the deregulated activity of nuclear factor-kappa B, the transcription factor responsible for the production of cytokines and mediators of the inflammatory responses due to cancer and/or cancer treatment. These concepts open exciting new avenues for translational research in the pathophysiology and treatment of cancer-related symptoms.

Cytokines↗
PubMed2004

Breast cancer and depression.

Major depression and depressive symptoms, although commonly encountered in patients with medical illnesses, are frequently underdiagnosed and undertreated in women with breast cancer. Depression and its associated symptoms diminish quality of life, adversely affect compliance with medical therapies, and reduce survival. Treatment of depression in women with breast cancer improves their dysphoria and other depressive symptoms, enhances quality of life, and may increase longevity. In this review, studies that investigate pathophysiologic alterations in patients with cancer and comorbid depression are discussed, and the few studies on treatment of depression and related symptoms in women with breast cancer are examined.

Antidepressive Agents↗
PubMed2003

Interferon-alpha-induced changes in tryptophan metabolism. relationship to depression and paroxetine treatment.

BACKGROUND: Tryptophan (TRP) degradation into kynurenine (KYN) by the enzyme, indoleamine-2,3-dioxygenase, during immune activation may contribute to development of depressive symptoms during interferon (IFN)-alpha therapy. METHODS: Twenty-six patients with malignant melanoma were randomly assigned in double-blind fashion to receive either placebo or paroxetine, beginning 2 weeks before IFN-alpha treatment and continuing for the first 12 weeks of IFN-alpha therapy. At treatment initiation and at 2, 4, and 12 weeks of IFN-alpha treatment, measurements of TRP, KYN, and neopterin (a marker of immune activation), were obtained, along with structured assessments of depression, anxiety, and neurotoxicity. RESULTS: Regardless of antidepressant treatment status, all patients exhibited significant increases in KYN, neopterin, and the KYN/TRP ratio during IFN-alpha therapy. Among antidepressant-free patients, patients who developed major depression exhibited significantly greater increases in KYN and neopterin concentrations and more prolonged decreases in TRP concentrations than did nondepressed, antidepressant-free patients. Moreover, in antidepressant-free patients, decreases in TRP correlated with depressive, anxious, and cognitive symptoms, but not neurovegetative or somatic symptoms. No correlations were found between clinical and biological variables in antidepressant-treated patients. CONCLUSIONS: The results suggest that reduced TRP availability plays a role in IFN-alpha-induced depressive symptoms, and paroxetine, although not altering the KYN or neopterin response to IFN-alpha, attenuates the behavioral consequences of IFN-alpha-mediated TRP depletion.

Adult↗
PubMed2003

Depression in cancer: new developments regarding diagnosis and treatment.

Considerable data demonstrate the high prevalence of symptoms of depression in patients with a wide variety of neoplastic disorders. Moreover, the dire consequences of these depressive symptoms in cancer patients have been well documented. Recent conceptual developments in the potential contributing mechanisms include increasing appreciation of the possibility that behavioral alterations in cancer patients may represent a "sickness syndrome" that results from activation of the inflammatory cytokine network. This sickness syndrome, which has been well documented in patients and laboratory animals exposed to inflammatory cytokines, includes symptoms that overlap with those seen in major depression. Conceptualizing these symptoms as components of cytokine-mediated sickness behavior has several important, and potentially novel, implications, including 1) an expansion of the neurobehavioral symptoms that are relevant to diagnosis and treatment; and 2) an increased appreciation of the potential diagnostic utility of peripheral markers of inflammation, as well as cytokine-related neurocircuitry alterations as defined by brain imaging. Treatment implications focus on the pathways by which inflammatory cytokines influence behavior, including therapeutic targets such as the inflammatory cytokines themselves, corticotropin-releasing hormone, and monoaminergic neurotransmitters and their precursors. Finally, recent data suggest that aggressive treatment strategies initiated before inflammation-inducing cancer treatments might prevent behavioral alterations, including depression, before they occur.

Antidepressive Agents↗
PubMed2003

Are the symptoms of cancer and cancer treatment due to a shared biologic mechanism? A cytokine-immunologic model of cancer symptoms.

BACKGROUND: Cancers and cancer treatments produce multiple symptoms that collectively cause a symptom burden for patients. These symptoms include pain, wasting, fatigue, cognitive impairment, anxiety, and depression, many of which co-occur. There is growing recognition that at least some of these symptoms may share common biologic mechanisms. METHODS: In November 2001, basic and clinical scientists met to consider evidence for a cytokine-immunologic model of symptom expression along with directions for future research. RESULTS: The characteristics of cytokine-induced sickness behavior in animal models have much in common with those of symptomatic cancer patients. Sickness behavior refers to a set of physiologic and behavioral responses observed in animals after the administration of infectious or inflammatory agents or certain proinflammatory cytokines. In some cases, these responses can be prevented by cytokine antagonists. A combination of animal and human research suggests that several cancer-related symptoms may involve the actions of proinflammatory cytokines. CONCLUSIONS: Based on the similarities between cancer symptoms and sickness behavior, the authors discussed approaches to further test the implications of the relationship between inflammatory cytokines and symptoms for both symptom treatment and symptom prevention.

Animals↗
PubMed2003

Relationship of clinical symptoms and substance use in schizophrenia patients on conventional versus atypical antipsychotics.

A large body of research documents the high prevalence and devastating consequences of substance abuse among individuals diagnosed with schizophrenia. One prominent theory of the high rate of comorbidity between these disorders is that substance abuse in schizophrenia is an attempt to self-medicate psychiatric symptoms including negative symptoms and depression as well as side effects including extrapyramidal reactions (EPR). Consistent with this notion, novel antipsychotic medications, which have been shown to reduce negative and depressive symptoms while exhibiting a lower propensity to cause EPR, have been associated with reduced substance abuse in patients with schizophrenia. To further explore the self-medication hypothesis as it relates to the mechanism by which atypical antipsychotics reduce substance abuse, we compared schizophrenia patients with a history of substance abuse medicated with either conventional (n = 35) or atypical (n = 35) antipsychotics. Patients with schizophrenia who did not have a history of substance abuse who were on conventional (n = 23) vs. atypical antipsychotics (n = 29) were also examined. Assessments included the Positive and Negative Symptom Scale, Hamilton Rating Scale for Depression, Simpson-Angus, and Abnormal Involuntary Movement Scale. Compared with conventional medications, atypical antipsychotic drugs were associated with reduced levels of substance use (primarily alcohol). Interestingly, however, in substance-abusing patients there were no significant differences between patients on conventional vs. atypical agents with respect to positive or negative symptoms, depression, or EPR. These data suggest that theories related to self-medication of symptoms and side effects do not appear to account for the difference in rates of substance use found in schizophrenia patients on atypical vs. conventional antipsychotic medications.

Adult↗
PubMed2003

Association of exaggerated HPA axis response to the initial injection of interferon-alpha with development of depression during interferon-alpha therapy.

OBJECTIVE: The authors assessed the relationship between the hypothalamic-pituitary-adrenal (HPA) axis response to interferon-alpha (IFN-alpha) and the development of major depression during IFN-alpha treatment. METHOD: Adrenocorticotropic hormone (ACTH), cortisol, and interleukin-6 (IL-6) plasma concentrations were measured in 14 patients with malignant melanoma at regular intervals during the first 12 weeks of IFN-alpha therapy, both immediately before and 1, 2, and 3 hours after IFN-alpha administration. Symptom criteria for major depression were also evaluated at each visit. RESULTS: ACTH and cortisol responses but not IL-6 responses to the initial administration of IFN-alpha were significantly higher in the seven patients who subsequently developed symptom criteria for major depression than in those who did not. No differences in hormonal or cytokine responses were found between these two groups during chronic IFN-alpha administration. CONCLUSIONS: The HPA axis response to the acute administration of IFN-alpha reveals a vulnerability to IFN-alpha-induced depression, possibly due to sensitization of corticotropin-releasing factor pathways.

Adrenocorticotropic Hormone↗
PubMed2003

When not enough is too much: the role of insufficient glucocorticoid signaling in the pathophysiology of stress-related disorders.

OBJECTIVE: Previous theories have emphasized the role of excessive glucocorticoid activity in the pathology of chronic stress. Nevertheless, insufficient glucocorticoid signaling (resulting from decreased hormone bioavailability or reduced hormone sensitivity) may have equally devastating effects on bodily function. Such effects may be related in part to the role of glucocorticoids in restraining activation of the immune system and other components of the stress response, including the sympathetic nervous system (SNS) and corticotropin-releasing hormone (CRH). METHOD: The literature on neuroendocrine function and glucocorticoid-relevant pathologies in stress-related neuropsychiatric disorders, including posttraumatic stress disorder and major depression, was reviewed. RESULTS: Although not occurring together, both hypocortisolism and reduced responsiveness to glucocorticoids (as determined by dexamethasone challenge tests) were reliably found. Stress-related neuropsychiatric disorders were also associated with immune system activation/inflammation, high SNS tone, and CRH hypersecretion, which are all consistent with insufficient glucocorticoid-mediated regulation of stress hyperresponsiveness. Finally, antidepressants, a mainstay in the treatment of stress-related disorders, were regularly associated with evidence of enhanced glucocorticoid signaling. CONCLUSIONS: Neuroendocrine data provide evidence of insufficient glucocorticoid signaling in stress-related neuropsychiatric disorders. Impaired feedback regulation of relevant stress responses, especially immune activation/inflammation, may, in turn, contribute to stress-related pathology, including alterations in behavior, insulin sensitivity, bone metabolism, and acquired immune responses. From an evolutionary perspective, reduced glucocorticoid signaling, whether achieved at the level of the hormone or its receptor, may foster immune readiness and increase arousal. Emphasis on insufficient glucocorticoid signaling in stress-related pathology encourages development of therapeutic strategies to enhance glucocorticoid signaling pathways.

Adrenocorticotropic Hormone↗
PubMed2003

[Neuro-immune interactions in psychopathology with the example of interferon-alpha-induced depression].

The use of interferon (IFN)-alpha for the treatment of viral diseases or cancers is associated with neuropsychiatric side effects in a large number of patients. The mechanisms by which cytokines induce these symptoms, as well as the vulnerability factors for these effects, have not been yet fully elucidated. Systematic clinical studies, combining biochemical approaches, functional brain imaging and treatment intervention, have been initiated to better understand the phenomenology, pathophysiology, and preventive strategies of the neuropsychiatric effects of IFN-alpha in patients with malignant melanoma or chronic hepatitis C. The findings indicate differential phenomenology and treatment responsiveness of the neurovegetative and mood/cognitive symptoms induced by IFN-alpha, suggesting distinct underlying mechanisms. Impaired neuroendocine function, fronto-striatal dysfunction and decreased monoamine were found to contribute to the pathophysiology of core symptoms of IFN-alpha-induced depression, including symptoms of mood alterations, cognitive dysfunction, anhedonia and psychomotor retardation. In addition, some behavioral and biological markers of the vulnerability for IFN-alpha-induced depression were identified. These findings provide important information concerning the relationship between cytokines and depression.

Depression↗
PubMed2002

Cerebrospinal fluid corticotropin-releasing factor (CRF) and vasopressin concentrations predict pituitary response in the CRF stimulation test: a multiple regression analysis.

There is considerable evidence that stress-related psychiatric disorders, including depression and post-traumatic stress disorder (PTSD), are associated with hypersecretion of corticotropin-releasing factor (CRF) within the central nervous system (CNS). One line of evidence that is consistent with central CRF hypersecretion in these disorders is the blunted adrenocorticotropin hormone (ACTH) response to intravenous CRF administration, likely a consequence, at least in part, of downregulation of anterior pituitary CRF receptors. The present study tests the hypothesis that elevated cerebrospinal fluid (CSF) concentrations of CRF and a secondary ACTH secretagogue, arginine vasopressin (AVP), are associated with diminished adenohypophyseal responses in a standard CRF stimulation test. CSF concentrations of CRF and AVP, and plasma ACTH responses to the administration of 1 microg/kg ovine CRF (oCRF) were measured in healthy adult women with and without current major depression and/or a history of significant childhood abuse. The primary outcome measure was ACTH area under the curve (AUC) in the CRF stimulation test. Multiple linear regression was performed to identify the impact of CSF CRF and AVP concentrations upon the pituitary response to CRF stimulation. The regression model explained 56.5% of the variation in the ACTH response to CRF stimulation. The relationship of CSF concentrations of CRF to ACTH responses to CRF were best described by a third-order function that was inversely correlated over most of the range of studied values. The association of ACTH response with CSF concentration of AVP and the dose of oCRF followed second-order kinetics. These findings support the hypothesis that central CRF hypersecretion is associated with a blunted ACTH response to exogenously administered CRF, explaining almost 60% of the variation in the ACTH response to CRF.

Adrenocorticotropic Hormone↗
PubMed2002

The role of early adverse experience and adulthood stress in the prediction of neuroendocrine stress reactivity in women: a multiple regression analysis.

Sensitization of stress-responsive neurobiological systems as a possible consequence of early adverse experience has been implicated in the pathophysiology of mood and anxiety disorders. In addition to early adversities, adulthood stressors are also known to precipitate the manifestation of these disorders. The present study sought to evaluate the relative role of early adverse experience vs. stress experiences in adulthood in the prediction of neuroendocrine stress reactivity in women. A total of 49 women (normal volunteers, depressed patients, and women with a history of early abuse) underwent a battery of interviews and completed dimensional rating scales on stress experiences and psychopathology, and were subsequently exposed to a standardized psychosocial laboratory stressor. Outcome measures were plasma adrenocorticotropin (ACTH) and cortisol responses to the stress test. Multiple linear regression analyses were performed to identify the impact of demographic variables, childhood abuse, adulthood trauma, major life events in the past year, and daily hassles in the past month, as well as psychopathology on hormonal stress responsiveness. Peak ACTH responses to psychosocial stress were predicted by a history of childhood abuse, the number of separate abuse events, the number of adulthood traumas, and the severity of depression. Similar predictors were identified for peak cortisol responses. Although abused women reported more severe negative life events in adulthood than controls, life events did not affect neuroendocrine reactivity. The regression model explained 35% of the variance of ACTH responses. The interaction of childhood abuse and adulthood trauma was the most powerful predictor of ACTH responsiveness. Our findings suggest that a history of childhood abuse per se is related to increased neuroendocrine stress reactivity, which is further enhanced when additional trauma is experienced in adulthood.

Adrenocorticotropic Hormone↗
PubMed2002

Neonatal viral infection decreases neuronal progenitors and impairs adult neurogenesis in the hippocampus.

While adult neurogenesis has been demonstrated in the hippocampal dentate gyrus of several mammalian species, including humans, the impact of viral infections has not been well studied. To examine this question we used a model in which neonatal rats are infected with lymphocytic choriomeningitis virus (LCMV) leading to a gradual loss of dentate granule cells (DGCs), which becomes fully evident in adulthood. Stereological cell counts performed 8 months after infection revealed that the loss of mature DGCs was accompanied by an 84.2% reduction in proliferation of DGCs as measured by BrdU uptake. Moreover, there was a severe loss of Mash1-labeled neuronal progenitor cells (87 and 83% decrease in the granule cell layer and hilus, respectively). Thus, neurogenesis is impaired in this model of chronic DGC loss, perhaps due to a virus-induced impoverishment of DGC neuronal progenitors. The LCMV model could be exploited to examine pathophysiological mechanisms of neurodegeneration and to test pharmacological strategies aimed at increasing neurogenesis or rescuing multipotent progenitors.

Animals↗
PubMed2002

Treatment of cytokine-induced depression.

A high proportion of cancer and hepatitis C patients who receive cytokine immunotherapy develop symptoms of depression that are indistinguishable from those found in major depressive disorders. These symptoms are alleviated by anti-depressant treatment. Moreover, preventive treatment with anti-depressants, in particular selective serotonin reuptake inhibitors (SSRIs) attenuates IFN-alpha-associated symptoms of depression, anxiety, and neurotoxicity. The intermediate mechanisms of these effects are still unclear. Studies suggest that the state of depression is associated with an increase in plasma levels of various cytokines and soluble cytokine receptors. Furthermore, anti-depressants have been shown to shift the cytokine network towards a decreased production of pro-inflammatory cytokines and an increased production of anti-inflammatory cytokines. Other studies suggest that anti-depressants can also modify immune reactivity by acting on neural structures involved in neuroimmunomodulation. It is possible that anti-depressants could help to normalize the serotoninergic neurotransmission that is likely disrupted during immunotherapy due to the potent effects of cytokines on the metabolism of the amino acid precursor tryptophan. Further work is needed to optimize strategies for preventing neuropsychiatric side effects of cytokine immunotherapy, to clarify the mechanisms involved in the alleviating effects of anti-depressants on cytokine-induced depression, as well as to assess the possible consequences of anti-depressant therapy on the efficacy of immunotherapy on the disease process.

Antidepressive Agents↗