The Association of Measures of the Micro- and Macro-Vasculature with Selenium and GPx Activity in a Young Bi-Ethnic Population: The African-PREDICT Study

Abstract

Objective: Selenium plays an important physiological role as component for antioxidant selenoproteins such as glutathione peroxidase (GPx). Since oxidative stress contributes to hypertension development, it is likely that selenium deficiency may contribute to the burden of cardiovascular disease. To better understand the involvement of selenium and GPx in the early development of cardiovascular disease, we investigated in young, healthy black and white African men and women whether measures of the micro- and macrovasculature are related to selenium and GPx activity.

Methods: In young adults (N?=?394; aged 20–30?years) we determined serum selenium, GPx activity, microvascular measures (central retinal artery equivalent, central retinal vein equivalent, arteriolar-to-venular ratio [AVR], and estimated glomerular filtration rate [eGFR]), and macrovascular measures (pulse wave velocity, 24-hour pulse pressure [PP] and augmentation index [Aix]).

Results: In multivariable-adjusted regression analyses, there were vasculoprotective associations between serum selenium and a microvascular measure (AVR [β?=?0.23; p?=?0.036]) in black African women and with a macrovascular measure (24-hour PP [β = ?0.15; p?=?0.048]) in white African women. In turn, GPx activity also showed a protective association with a microvascular measure (eGFR) in white African men (β?=?0.23; p?=?0.035), as well as with macrovascular measures (AIx, PP) in the black (β = ?0.25; p?=?0.027) and white African men (β = ?0.22; p?=?0.035), and black African women (β = ?0.32; p?=?0.001).

Conclusions: Collectively the findings suggest a protective role for the micronutrient selenium and GPx on both the micro- and macrovasculature in a young, healthy bi-ethnic population.     

Whole body MRI: Improved lesion detection and characterization with diffusion weighted techniques

Diffusion‐weighted imaging (DWI) is an established functional imaging technique that interrogates the delicate balance of water movement at the cellular level. Technological advances enable this technique to be applied to whole‐body MRI. Theory, b‐value selection, common artifacts and target to background for optimized viewing will be reviewed for applications in the neck, chest, abdomen, and pelvis. Whole‐body imaging with DWI allows novel applications of MRI to aid in evaluation of conditions such as multiple myeloma, lymphoma, and skeletal metastases, while the quantitative nature of this technique permits evaluation of response to therapy. Persisting signal at high b‐values from restricted hypercellular tissue and viscous fluid also permits applications of DWI beyond oncologic imaging. DWI, when used in conjunction with routine imaging, can assist in detecting hemorrhagic degradation products, infection/abscess, and inflammation in colitis, while aiding with discrimination of free fluid and empyema, while limiting the need for intravenous contrast. DWI in conjunction with routine anatomic images provides a platform to improve lesion detection and characterization with findings rivaling other combined anatomic and functional imaging techniques, with the added benefit of no ionizing radiation. J. Magn. Reson. Imaging 2013;38:253–268. © 2013 Wiley Periodicals, Inc.