Classical Risk Factors and Inflammatory Biomarkers: One of the Missing Biological Links between Cardiovascular Disease and Major Depressive Disorder.

BACKGROUND: Cardiovascular disorders (CVD) and major depressive disorder (MDD) are the most frequent diseases worldwide responsible for premature death and disability. Behavioral and immunological variables influence the pathophysiology of both disorders. We therefore determined frequency and severity of MDD in CVD and studied whether MDD without CVD or other somatic diseases influences classical and inflammatory biomarkers of cardiovascular risk. In addition, we investigated the influence of proinflammatory cytokines on antidepressant treatment outcome. METHODS: In a case-control design, 310 adults (MDD patients without CVD, CVD patients, and cardiologically and psychiatrically healthy matched controls) were investigated. MDD patients were recruited after admission in a psychiatric university hospital. Primary outcome criteria were clinical depression ratings (HAM-D scale), vital signs, classical cardiovascular risk factors and inflammatory biomarkers which were compared between MDD patients and healthy controls. RESULTS: We detected an enhanced cardiovascular risk in MDD. Untreated prehypertension and signs directing to a metabolic syndrome were detected in MDD. Significantly higher inflammatory biomarkers such as the high sensitivity C-reaktive protein (hsCRP) and proinflammatory acute phase cytokines interleukine-1ß (IL-1ß) and interleukine-6 (IL-6) underlined the higher cardiovascular risk in physically healthy MDD patients. Surprisingly, high inflammation markers before treatment were associated with better clinical outcome and faster remission. The rate of MDD in CVD patients was high. CONCLUSIONS: Patients suffering from MDD are at specific risk for CVD. Precise detection of cardiovascular risks in MDD beyond classical risk factors is warranted to allow effective prophylaxis and treatment of both conditions. Future studies of prophylactic interventions may help to provide a basis for prophylactic treatment of both MDD and CVD. In addition, the high risk for MDD in CVD patients was confirmed and underlines the requirement for clinical attention.

DNA methylation analysis of the angiotensin converting enzyme (ACE) gene in major depression.

BACKGROUND: The angiotensin converting enzyme (ACE) has been repeatedly discussed as susceptibility factor for major depression (MD) and the bi-directional relation between MD and cardiovascular disorders (CVD). In this context, functional polymorphisms of the ACE gene have been linked to depression, to antidepressant treatment response, to ACE serum concentrations, as well as to hypertension, myocardial infarction and CVD risk markers. The mostly investigated ACE Ins/Del polymorphism accounts for ~40%-50% of the ACE serum concentration variance, the remaining half is probably determined by other genetic, environmental or epigenetic factors, but these are poorly understood. MATERIALS AND METHODS: The main aim of the present study was the analysis of the DNA methylation pattern in the regulatory region of the ACE gene in peripheral leukocytes of 81 MD patients and 81 healthy controls. RESULTS: We detected intensive DNA methylation within a recently described, functional important region of the ACE gene promoter including hypermethylation in depressed patients (p = 0.008) and a significant inverse correlation between the ACE serum concentration and ACE promoter methylation frequency in the total sample (p = 0.02). Furthermore, a significant inverse correlation between the concentrations of the inflammatory CVD risk markers ICAM-1, E-selectin and P-selectin and the degree of ACE promoter methylation in MD patients could be demonstrated (p = 0.01 - 0.04). CONCLUSION: The results of the present study suggest that aberrations in ACE promoter DNA methylation may be an underlying cause of MD and probably a common pathogenic factor for the bi-directional relationship between MD and cardiovascular disorders.

Major depressive disorder is associated with cardiovascular risk factors and low Omega-3 Index.

OBJECTIVE: Cardiovascular disease (CVD) and major depressive disorder (MDD) are frequent worldwide and have a high comorbidity rate. Omega-3 fatty acids have been suggested as disease modulators for both CVD and MDD. Therefore, we studied whether polyunsaturated fatty acids and the Omega-3 Index may represent markers for assessment of the cardiovascular risk in somatically healthy patients suffering from MDD. METHOD: We conducted a case-control study from July 2004 to December 2007 in 166 adults (86 inpatients with MDD but without CVD from the Department of Psychiatry and Psychotherapy and 80 age- and sex-matched healthy controls from an outpatient clinic of the Division of Preventive Cardiology, Ludwig Maximilian University of Munich, Germany). Information gathered at baseline included MDD diagnosis according to DSM-IV criteria, depression ratings, conventional cardiovascular risk factors, and fatty acid and interleukin-6 determinations. Fatty acid composition was analyzed according to the HS-Omega-3 Index methodology. During the study, patients received no supplementation with omega-3 fatty acids. The main inclusion criteria were the diagnosis of MDD according to DSM-IV and a 17-item Hamilton Depression Rating Scale (HDRS-17) score of at least 17. Treatment response and remission were defined using the HDRS-17. RESULTS: Several conventional risk factors such as high triglyceride (mean, 152 mg/dL vs 100 mg/dL; P < .001) and fasting glucose (mean, 96 mg/dL vs 87 mg/dL; P = .005) values as well as greater waist circumference (mean, 97 cm vs 87 cm; P = .019) and higher body mass index (calculated as kg/m(2); mean, 26 vs 24; P = .011) were more prevalent in MDD patients in comparison with controls. The Omega-3 Index (mean, 3.9% vs 5.1%; P < .001) and individual omega-3 fatty acids were significantly lower in MDD patients. An Omega-3 Index < 4% was associated with high concentrations of the proinflammatory cytokine interleukin-6 (χ(2) = 7.8, P = .02). CONCLUSIONS: Conventional cardiovascular risk factors, the Omega-3 Index, and interleukin-6 levels indicated an elevated cardiovascular risk profile in MDD patients currently free of CVD. Our results support the employment of strategies to reduce the cardiovascular risk in still cardiovascularly healthy MDD patients by targeting conventional risk factors and the Omega-3 Index.