Abstract 4963: Cerebral Microvascular Damage in Elderly Depressed Patients is Associated With Structural and Functional Abnormalities of Subcutaneous Small Arteries
Introduction: Late-life depression is increasingly viewed as a vascular illness with patients exhibiting characteristic white matter brain lesions and in-vivo endothelial dysfunction. Although the ‘vascular depression’ hypothesis pertains to the microvasculature, this circulation has yet to be studied.
Methods and Results: 25 patients aged 72.6±5.4 years with late-life depression were compared with 21 control participants aged 72.4±6.5 years. The groups were matched for blood pressure, glycaemia, lipids, co-morbidities and treatment with statins and agents modifying the renin-angiotensin axis. Patients underwent MRI brain scan and a matched subset underwent subcutaneous gluteal fat biopsy (15 patients and 15 control participants) from which small arteries were isolated and studied using pressure myography. Depressed patients showed evidence of cerebral microvascular damage (MRI scan): Virchow Robin Scores- Patients:3.88±1.45 vs Controls:2.76±1.55, p=0.01, White Matter Lesions- Patients:342±748.1 vs Controls:202±881, p=ns. Small artery studies demonstrated endothelial dysfunction (Percentage relaxation: Patients:82±4% vs Controls:96±1.5%, p<0.05) which was not completely explained by reduced nitric oxide synthase bioavailability (Relaxation after LNMMA incubation: Patients:67±5.6% vs Controls:83±11%, p<0.05). Contractility to Nor-adrenaline was equivalent between the groups. There was also abnormal hypertrophic wall growth in depressed patients (Medial Cross sectional area: Patients:13294μm2 vs Controls:10555 μm2, p<0.05, Growth Index: 26%), but no difference in arterial distensibility.
Conclusions: Despite identical cardiovascular profiles, patients with late-life depression show profound abnormalities in both structure and function of small arteries, suggestive of deficiencies in local autoregulation. Although the arteries taken were from subcutaneous fat, our findings are in support of cerebral microvascular pathology in this condition.