Health Evaluation in African Americans Using RAS Therapy

The cerebrospinal fluid renin-angiotensin system (RAS) was assessed by measuring levels of angiotensin metabolites in a 1 milliliter (mL) sample of cerebrospinal fluid (CSF). ACE 1 helps to regulate blood pressure by converting angiotensin I to angiotensin II.

The cerebrospinal fluid renin-angiotensin system (RAS) was assessed by measuring levels of angiotensin metabolites in a 1 milliliter (mL) sample of cerebrospinal fluid (CSF). ACE 2 regulates levels of circulating angiotensin II. ACE 2 increases during illness and with Alzheimer's disease.

Levels of amyloid β40 (Aβ40) in the cerebrospinal fluid were measured using LUMIPULSE® technology. The relationship between Aβ40 is non-linear with moderate levels showing the highest risk of future cognitive decline in some studies.

Levels of amyloid β42 (Aβ42) in the cerebrospinal fluid were measured using LUMIPULSE® technology. Decreases in concentrations of amyloid β42 are indicative of a decrease in cognitive function.

Levels of T-tau in the cerebrospinal fluid were measured using LUMIPULSE® technology. Increases in concentrations of T-tau are indicative of a decrease in cognitive function.

Levels of P-tau in the cerebrospinal fluid were measured using LUMIPULSE® technology. Increases in concentrations of P-tau are indicative of a decrease in cognitive function.

The inflammatory marker IL-6 in CSF was examined.

The inflammatory marker IL-7 in CSF was examined.

The inflammatory marker IL-8 in CSF was examined.

The inflammatory marker IL-9 in CSF was examined.

The inflammatory marker IL-10 in CSF was examined.

Monocyte chemoattractant protein 1 inflammatory markers in CSF were examined.

Macrophage derived protein 1 inflammatory markers in CSF were examined.

Transforming growth factor alpha inflammatory markers in CSF were examined.

Tumor necrosis factor alpha inflammatory markers in CSF were examined.

Intercellular adhesion molecule 1 inflammatory markers in CSF were examined.

Vascular cell adhesion molecule 1 inflammatory markers in CSF were examined.

Matrix metalloproteinase inflammatory markers will be examined in CSF.

Tissue inhibitor of metalloproteinase inflammatory markers will be examined in CSF.

Soluble Platelet-Derived Growth Factor Receptor Beta (sPDGFRβ) is a marker of breakdown in the blood brain barrier. Increased levels of sPDGFRβ indicate cognitive dysfunction.

High-resolution anatomical images will be acquired using a 3D-Fast Spoiled Gradient Recalled Echo (FSPGR) Sequence. White Matter Hyperintensities (WMH) will be identified by a 3D T2 Fluid Attenuated Inversion Recovery (FLAIR) Fast Spin Echo sequence. The images will be co-registered using a within-subject inter-modal alignment between structural and perfusion images. T1-weighted Spoiled Gradient Recalled (SPGR) images will be used to identify cerebrospinal fluid and white and gray matter. Increased volumes of white matter hyperintensities indicate impaired cognitive function.

Echoplanar T1 mapping scans will be used for image registration and a scout image of the head will be obtained in order to choose the appropriate location for spin labeling and flow imaging. Arterial Spin Labeling images will be acquired using a custom 3D stack of interleaved spirals fast spin echo sequences and will be averaged in order to improve the signal-to-noise ratio. Images will be interpolated and smoothed in a panel by using a 0.5-pixel, full-width, half-maximum Gaussian kernel. Regional perfusion will be quantified in each hemisphere and maps of cerebral vasoreactivity will be obtained by co-registration of perfusion and anatomical images.