Eduard Suy

Bio: Eduard Suy is an academic researcher from University of Antwerp. The author has contributed to research in topics: Dexamethasone suppression test & Hydrocortisone. The author has an hindex of 28, co-authored 52 publications receiving 3140 citations.

Relationships between interleukin-6 activity, acute phase proteins, and function of the hypothalamic-pituitary-adrenal axis in severe depression.

Abstract: Recent studies from this laboratory have provided some evidence that major depression, in particular melancholia, may be accompanied by an immune response. The present study was designed to investigate whether severe depression is characterized by increased interleukin-6 (Il-6) activity and whether Il-6 production is related to altered levels of acute phase reactants and to abnormal function of the hypothalamic-pituitary-adrenal (HPA) axis. Measurements were made in 8 healthy control subjects and 24 depressed inpatients of Il-6 production in culture supernatants of mitogen-stimulated peripheral leukocytes and plasma levels of haptoglobin (Hp), transferrin (Tf), and postdexamethasone cortisol. Il-6 activity was significantly higher in melancholic subjects than in healthy control subjects and in patients with minor depression or nonmelancholic major depression. Il-6 production was significantly correlated with Hp (positively) and Tf (negatively) plasma levels. There were significant and positive correlations between Il-6 activity and postdexamethasone cortisol values. The findings may suggest that increased Il-6 activity in severe depression is related to hypotransferrinemia, hyperhaptoglobinemia, and hyperactivity of the HPA axis.

Interleukin-1 beta: a putative mediator of HPA axis hyperactivity in major depression?

Abstract: Objective There is extensive evidence that major depression, and particularly melancholia, is characterized by hypothalamic-pituitary-adrenal (HPA) axis hyperactivity as well as systemic immune activation, which may be accompanied by increased interleukin-1 beta production. Interleukin-1 beta is known to enhance HPA axis activity during an immune response. This study investigated whether interleukin-1 beta production is related to HPA axis activity in depressed subjects. Method The subjects were 28 inpatients with major or minor depression and 10 normal comparison subjects. The authors measured 1) the subjects' cortisol levels after an overnight 1-mg dexamethasone suppression test (DST) and 2) mitogen-stimulated supernatant interleukin-1 beta production by peripheral blood mononuclear cells. Results Statistically significant positive correlations between interleukin-1 beta production and post-DST cortisol values were found in the study group as a whole and in the depressed and normal subgroups separately. Conclusions It is suggested that constituents of the immune response (such as interleukin-1 beta) in major depression may contribute to HPA axis hyperfunction in that illness.

Depression‐related disturbances in mitogen‐induced lymphocyte responses and interleukin‐1β and soluble interleukin‐2 receptor production

Abstract: In an attempt to delineate the pathophysiology underpinning the previously reported blunted lymphocyte responses to mitogenic stimulation in depressed patients, we measured the following immune variables in 28 depressives and 10 healthy controls: pre- and postdexamethasone (1 mg orally) lymphocyte responses to various mitogens, such as phytohaemagglutinin (PHA), and the PHA-induced accumulation of interleukin-1 beta (Il-1 beta) and soluble interleukin-2-receptors (sIl-2Rs) in culture supernatants. In the predexamethasone state, we found significantly more mitogen-stimulated blastogenesis in minor depressives vs healthy controls and major depressives. In depressed subjects there was a significant inverse relationship between the severity of illness and the mitogen-induced lymphocyte responses. Melancholics exhibited significantly more Il-1 beta accumulation in PHA culture supernatant than healthy controls. In healthy controls--but not in depressed patients--the sIl-2R accumulation perfectly reflects the magnitude of the PHA-induced lymphocyte stimulation. Dexamethasone administration significantly suppressed the lectin-induced blastogenesis and the Il-1 beta production rate in normal volunteers, whereas depressives exhibited dexamethasone nonsuppression in those factors. Healthy controls exhibited significantly less postdexamethasone blast transformation, Il-1 beta and sIl-2Rs accumulation in culture supernatant than the depressed patients.

Evidence for a systemic immune activation during depression: results of leukocyte enumeration by flow cytometry in conjunction with monoclonal antibody staining.

Abstract: Several studies have reported a suppressed immune function (e.g. blast transformation) during depression. In an attempt to define the cellular basis of the reported immune disorders, the present study investigates the leukocyte cell subset profile of minor, simple major, and melancholic depressives, versus normal controls. We have counted the number of white blood cells (WBC) lymphocytes, monocytes, and granulocytes, while the number of lymphocyte (sub)populations has been identified by phenotype, using monoclonal antibody staining in conjunction with flow cytometry. The following cell surface antigens were determined: CD3+ (pan T), CD19+ (pan B), CD4+ (T helper/inducer), CD8+ (T suppressor/cytotoxic), CD4+CD45RA (T-memory cells), CD4+CD45RA+ (T-virgin cells), surface Ig, class II MHC HLA-DR, and CD25+ (IL-2 receptor). By means of pattern recognition methods, we established distinct immunological changes in minor and simple major depressed and in melancholic patients, setting them apart from the reference population. Depression, per se, is characterized by a higher number of WBC, monocytes, class II MHC HLA-DR, and memory T cells. Minor and simple major depressives exhibited an increased T helper/suppressor ratio. Increased numbers of IL-2 receptor bearing cells are a hallmark for major depression. Melancholics showed an increased number of pan T, pan B and T suppressor/cytotoxic cells. It was concluded that the established immune cell profile of depressed patients may point towards the existence of a systemic immune activation during that illness.

Immune Disturbances during Major Depression: Upregulated Expression of Interleukin-2 Receptors

Abstract: We determined the following immune parameters in drug-free, major depressed patients and in age- and sex-matched healthy controls: the number and percentage of interleukin-2 receptor (IL-2R) bearing cells (CD25+, anti-TAC), serum circulating levels of soluble (s)IL-2Rs, the pre- and postdexamethasone phytohemagglutinin (PHA)-induced accumulation of sIL-2Rs in culture supernatant, and the number of T helper (CD4+) and T suppressor (CD8+) cells. In comparison with normal volunteers, patients with major depression had a higher number and percentage of CD25+ cells, higher concentrations of serum circulating sIL-2Rs, higher supernatant sIL-2Rs after stimulation with PHA, and a higher number of CD4+ cells. The CD4+/CD8+ ratio and the number of CD4+ cells were significantly and positively related to the number of cells expressing the CD25+ antigen. These results may indicate that depressed patients display an increased number of T cells in an early phase of activation.

From Stress to Inflammation and Major Depressive Disorder: A Social Signal Transduction Theory of Depression

Abstract: Major life stressors, especially those involving interpersonal stress and social rejection, are among the strongest proximal risk factors for depression. In this review, we propose a biologically plausible, multilevel theory that describes neural, physiologic, molecular, and genomic mechanisms that link experiences of social-environmental stress with internal biological processes that drive depression pathogenesis. Central to this social signal transduction theory of depression is the hypothesis that experiences of social threat and adversity up-regulate components of the immune system involved in inflammation. The key mediators of this response, called proinflammatory cytokines, can in turn elicit profound changes in behavior, which include the initiation of depressive symptoms such as sad mood, anhedonia, fatigue, psychomotor retardation, and social-behavioral withdrawal. This highly conserved biological response to adversity is critical for survival during times of actual physical threat or injury. However, this response can also be activated by modern-day social, symbolic, or imagined threats, leading to an increasingly proinflammatory phenotype that may be a key phenomenon driving depression pathogenesis and recurrence, as well as the overlap of depression with several somatic conditions including asthma, rheumatoid arthritis, chronic pain, metabolic syndrome, cardiovascular disease, obesity, and neurodegeneration. Insights from this theory may thus shed light on several important questions including how depression develops, why it frequently recurs, why it is strongly predicted by early life stress, and why it often co-occurs with symptoms of anxiety and with certain physical disease conditions. This work may also suggest new opportunities for preventing and treating depression by targeting inflammation.

Guidelines for the Treatment of Hypothyroidism: Prepared by the American Thyroid Association Task Force on Thyroid Hormone Replacement

Abstract: Background: A number of recent advances in our understanding of thyroid physiology may shed light on why some patients feel unwell while taking levothyroxine monotherapy. The purpose of this task force was to review the goals of levothyroxine therapy, the optimal prescription of conventional levothyroxine therapy, the sources of dissatisfaction with levothyroxine therapy, the evidence on treatment alternatives, and the relevant knowledge gaps. We wished to determine whether there are sufficient new data generated by well-designed studies to provide reason to pursue such therapies and change the current standard of care. This document is intended to inform clinical decision-making on thyroid hormone replacement therapy; it is not a replacement for individualized clinical judgment. Methods: Task force members identified 24 questions relevant to the treatment of hypothyroidism. The clinical literature relating to each question was then reviewed. Clinical reviews were supplemented, when relevant, with related...

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

Abstract: OBJECTIVE: Previous theories have emphasized the role of excessive glucocorticoid activity in the pathology of chronic stress. Nevertheless, insufficient glucocorticoid signaling (resulting from de...