Comprehensive Characterization of Cerebrovascular Dysfunction in Blast Traumatic Brain Injury Using Photoacoustic Microscopy.

Blast traumatic brain injury (bTBI) is a leading contributor to combat-related injuries and death. Although substantial emphasis has been placed on blast-induced neuronal and axonal injuries, co-existing dysfunctions in the cerebral vasculature, particularly the microvasculature, remain poorly understood. Here, we studied blast-induced cerebrovascular dysfunctions in a rat model of bTBI (blast overpressure: 187.

Molecular imaging of endothelial vascular cell adhesion molecule-1 expression and inflammatory cell recruitment during vasculogenesis and ischemia-mediated arteriogenesis.

Background: Inflammatory responses contribute to vascular remodeling during tissue repair or ischemia. We hypothesized that inflammatory cell recruitment and endothelial cell activation during vasculogenesis and ischemia-mediated arteriogenesis could be temporally assessed by noninvasive molecular imaging.

Methods And Results: Contrast ultrasound perfusion imaging and molecular imaging with microbubbles targeted to activated neutrophils, alpha(5)-integrins, or vascular cell adhesion molecule (VCAM-1) were performed in murine models of vasculogenesis (subcutaneous matrigel) or hind-limb ischemia produced by arterial occlusion in wild-type or monocyte chemotactic protein-1-deficient mice.

Skeletal muscle capillary responses to insulin are abnormal in late-stage diabetes and are restored by angiotensin-converting enzyme inhibition.

Acute physiological hyperinsulinemia increases skeletal muscle capillary blood volume (CBV), presumably to augment glucose and insulin delivery. We hypothesized that insulin-mediated changes in CBV are impaired in type 2 diabetes mellitus (DM) and are improved by angiotensin-converting enzyme inhibition (ACE-I). Zucker obese diabetic rats (ZDF, n = 18) and control rats (n = 9) were studied at 20 wk of age.

Vasopressin is a physiological substrate for the insulin-regulated aminopeptidase IRAP.

Insulin-regulated aminopeptidase (IRAP) is a membrane aminopeptidase and is homologous to the placental leucine aminopeptidase, P-LAP. IRAP has a wide distribution but has been best characterized in adipocytes and myocytes. In these cells, IRAP colocalizes with the glucose transporter GLUT4 to intracellular vesicles and, like GLUT4, translocates from these vesicles to the cell surface in response to insulin.

High-resolution myocardial perfusion imaging in mice with high-frequency echocardiographic detection of a depot contrast agent.

High-resolution methods for assessing myocardial perfusion in murine models of cardiovascular disease are needed. We hypothesized that regional hypoperfusion could be assessed with ultrahigh-frequency myocardial contrast echocardiography (MCE) and a novel strategy of depot contrast enhancement. MCE was performed with 30-MHz transthoracic imaging 10 seconds and 10 minutes after intravenous administration of microbubbles in control mice, and in mice after left anterior descending coronary artery ligation.

Effect of microbubble ligation to cells on ultrasound signal enhancement: implications for targeted imaging.

Objectives: Molecular imaging with contrast-enhanced ultrasound (CEU) relies on the detection of microbubbles retained in regions of disease. The aim of this study was to determine whether microbubble attachment to cells influences their acoustic signal generation and stability.

Materials And Methods: Biotinylated microbubbles were attached to streptavidin-coated plates to derive density versus intensity relations during low- and high-power imaging.