Depression is also associated with systemic physiologic derangements which may contribute to vascular pathology. As mentioned above, HPA axis dysregulation with hypercortisolemia is common in depressed individuals. Elevated Cortisol levels independently Temozolomide cost predict several features of the metabolic syndrome including abdominal obesity, low high-density lipoprotein (HDL) levels, and hypertriglyceridemia.74 They disrupt normal endothelial function75 and may contribute over time to the development, of hypertension in some cases.76,77 Depressed subjects with coronary artery disease (CAD) exhibit, autonomic dysfunction with decreased
heart rate variability,78 a condition that likely predisposes to both Inhibitors,research,lifescience,medical cardiac arrhythmias and episodic hypoperfusion. Depressed individuals with and without. CAD show greater baseline platelet activation than nondepressed control subjects79-82, suggesting greater susceptibility to Inhibitors,research,lifescience,medical thromboembolic events. Finally, cross-sectional studies have linked depression to elevations in proinflammatory cytokines.83 While the causal relationship between such immunologic changes and depression is unknown, a similar proinflammatory cytokine shift is observed in atherosclerotic and thromboembolic disease Inhibitors,research,lifescience,medical states.84 C-reactive-protein is directly atherogenic, and high levels
of several proinflammatory cytokines have been found to predict cardiovascular events.85,86 In a reciprocal fashion, many acute and chronic vascular disease states
may promote depression. MI and stroke substantially increase risk for depression during the immediate postacute period, with depressive symptoms reported in 25% to 50% of individuals (reviewed in ref 67). One study comparing cumulative Inhibitors,research,lifescience,medical Inhibitors,research,lifescience,medical 1 -year incidence of major and minor depression immediately following stroke or MI found no difference between these groups.87 This finding suggests that the loss of specific neuronal populations is less important than more global postischemic vascular or inflammatory mechanisms in the pathogenesis of poststroke depression. Accordingly, depression is more frequent and severe in vascular dementia than AD,88 despite widespread neuronal loss in Cell press both dementia syndromes. Studies of individuals with chronic cardiovascular diseases show that diabetes mcllitus (sec meta-analysis in ref 89) and CAD,90 each approximately double risk for depression. Many but. not all studies of older subjects indicate a longitudinal association between vascular disease/risk and subsequent depression. Several prospective studies in elderly subjects report that clusters of cardiovascular risk factors or pre-existing CAD independently predict incident depression, while at least, one large prospective study found no relationship between an index of generalized atherosclerosis and incident depression.