Retinal microvascular function and incidence and trajectories of clinically relevant depressive symptoms: the Maastricht Study.

BACKGROUND: Cerebral microvascular dysfunction may contribute to depression via disruption of brain structures involved in mood regulation, but evidence is limited. We investigated the association of retinal microvascular function, a proxy for microvascular function in the brain, with incidence and trajectories of clinically relevant depressive symptoms. METHODS: Longitudinal data are from The Maastricht Study of 5952 participants (59.9 ± 8.5 years/49.7% women) without clinically relevant depressive symptoms at baseline (2010-2017). Central retinal arteriolar equivalent and central retinal venular equivalent (CRAE and CRVE) and a composite score of flicker light-induced retinal arteriolar and venular dilation were assessed at baseline. We assessed incidence and trajectories of clinically relevant depressive symptoms (9-item Patient Health Questionnaire score ⩾10). Trajectories included continuously low prevalence (low, n = 5225 [87.8%]); early increasing, then chronic high prevalence (early-chronic, n = 157 [2.6%]); low, then increasing prevalence (late-increasing, n = 247 [4.2%]); and remitting prevalence (remitting, n = 323 [5.4%]). RESULTS: After a median follow-up of 7.0 years (range 1.0-11.0), 806 (13.5%) individuals had incident clinically relevant depressive symptoms. After full adjustment, a larger CRAE and CRVE were each associated with a lower risk of clinically relevant depressive symptoms (hazard ratios [HRs] per standard deviation [s.d.]: 0.89 [95% confidence interval (CI) 0.83-0.96] and 0.93 [0.86-0.99], respectively), while a lower flicker light-induced retinal dilation was associated with a higher risk of clinically relevant depressive symptoms (HR per s.d.: 1.10 [1.01-1.20]). Compared to the low trajectory, a larger CRAE was associated with lower odds of belonging to the early-chronic trajectory (OR: 0.83 [0.69-0.99]) and a lower flicker light-induced retinal dilation was associated with higher odds of belonging to the remitting trajectory (OR: 1.23 [1.07-1.43]). CONCLUSIONS: These findings support the hypothesis that cerebral microvascular dysfunction contributes to the development of depressive symptoms.

Microvascular Dysfunction and Whole-Brain White Matter Connectivity: The Maastricht Study.

BACKGROUND: Microvascular dysfunction is involved in the development of various cerebral disorders. It may contribute to these disorders by disrupting white matter tracts and altering brain connectivity, but evidence is scarce. We investigated the association between multiple biomarkers of microvascular function and whole-brain white matter connectivity. METHODS AND RESULTS: Cross-sectional data from The Maastricht Study, a Dutch population-based cohort (n=4326; age, 59.4±8.6 years; 49.7% women). Measures of microvascular function included urinary albumin excretion, central retinal arteriolar and venular calibers, composite scores of flicker light-induced retinal arteriolar and venular dilation, and plasma biomarkers of endothelial dysfunction (intercellular adhesion molecule-1, vascular cell adhesion molecule-1, E-selectin, and von Willebrand factor). White matter connectivity was calculated from 3T diffusion magnetic resonance imaging to quantify the number (average node degree) and organization (characteristic path length, global efficiency, clustering coefficient, and local efficiency) of white matter connections. A higher plasma biomarkers of endothelial dysfunction composite score was associated with a longer characteristic path length (ß per SD, 0.066 [95% CI, 0.017-0.114]) after adjustment for sociodemographic, lifestyle, and cardiovascular factors but not with any of the other white matter connectivity measures. After multiple comparison correction, this association was nonsignificant. None of the other microvascular function measures were associated with any of the connectivity measures. CONCLUSIONS: These findings suggest that microvascular dysfunction as measured by indirect markers is not associated with whole-brain white matter connectivity.

Quantification of muscle mass in the legs of patients with peripheral arterial occlusive disease: associations between volumetric and cross-sectional single-slice measurements for identification of atrophy and focal sarcopenia.

BACKGROUND: Sarcopenia, commonly determined by measuring skeletal muscle mass index (SMI) at the third lumbar level, has been identified as a predictor of clinical outcome in a variety of diseases. For patients with peripheral arterial occlusive disease (PAOD), we hypothesized that lower extremity SMI (LESMI) might be a more precise predictor of outcome and the extent of chronic ischemia than the systemic muscle mass at the L3 level. We investigated the association between complete muscle volume and muscle area derived with single-slice 2-dimensional measurements in the legs to identify at which level cross-sectional single-slice measurements are most representative of the muscle volume and investigated whether LESMI is associated with systemic sarcopenia and PAOD severity. METHODS: Muscle volumes and areas were semiautomatically segmented from computed tomography (CT) scans of the affected and contralateral legs of 50 PAOD patients with Fontaine stage IIb and 50 PAOD patients with Fontaine stage IV. The muscle mass was determined for the complete volumes of the upper and lower legs and for cross-sectional slices at 40%, 50%, and 60% of the length of the femur and tibia. Patients were determined as sarcopenic based on sex-specific cut-off values at the L3 spinal segment. Two observers segmented 20 randomly selected patients to determine the interobserver reliability with the intraclass correlation coefficient. RESULTS: The correlation between the LESMI of the complete muscle volume and the three cross-sectional slices in all 200 upper and 200 lower legs was moderately strong to strong. Interobserver reliability of cross-sectional slice segmentation was excellent. The LESMI, both measured volumetrically and cross-sectionally, were significantly lower in patients with sarcopenia compared to patients without sarcopenia. The LESMI was lower in patients with Fontaine stage IV compared to patients with Fontaine stage IIb for both volumetric and cross-sectional measurements. CONCLUSIONS: Segmentation of skeletal muscle mass from cross-sectional single-slice CT in the upper and lower leg can accurately and precisely substitute complete volume segmentations. These findings warrant the use of measurements based on cross-sectional single-slice CT for assessing the LESMI. Patients with systemic sarcopenia are also at increased risk for muscle mass loss in the lower extremities. In the current study, LESMI was lower in patients with Fontaine class IV PAOD compared to patients with Fontaine class IIb PAOD. Future studies should assess the predictive value of the LESMI on clinical outcomes in PAOD patients.