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Brain Endothelial Erythrophagocytosis And Hemoglobin Transmigration Across Brain Endothelium: Implications For Pathogenesis Of Cerebral Microbleeds, Rudy Chang, Juan Castillo, Alexander C. Zambon, Tatiana B. Krasieva, Mark J. Fisher, Rachita K. Sumbria

Pharmacy Faculty Articles and Research

Peripheral endothelial cells are capable of erythrophagocytosis, but data on brain endothelial erythrophagocytosis are limited. We studied the relationship between brain endothelial erythrophagocytosis and cerebral microhemorrhage, the pathological substrate of MRI-demonstrable cerebral microbleeds. To demonstrate the erythrophagocytic capability of the brain endothelium, we studied the interactions between brain endothelial cells and red blood cells exposed to oxidative stress in vitro, and developed a new in vitro cerebral microbleeds model to study the subsequent passage of hemoglobin across the brain endothelial monolayer. Using multiple approaches, our results show marked brain endothelial erythrophagocytosis of red blood cells exposed to oxidative stress compared …

Aging Exacerbates Development Of Cerebral Microbleeds In A Mouse Model, Rachita K. Sumbria, Mher Mahoney Grigoryan, Vitaly Vasilevko, Annlia Paganini-Hill, Kelley Kilday, Ronald Kim, David H. Cribbs, Mark J. Fisher

Pharmacy Faculty Articles and Research

Background: Cerebral microhemorrhages (CMH) are commonly found in the aging brain. CMH are also the neuropathological substrate of cerebral microbleeds (CMB), demonstrated on brain MRI. Recent studies demonstrate the importance of systemic inflammation in CMH development, but the relationships among inflammation, aging, and CMH development are not well-defined. In the current study, we hypothesized that the pathogenesis of inflammation-induced CMH in mice differs by age.

Methods: We studied young (3 months, n = 20) and old (18 months, n = 25) C57BL/6 mice injected with low-dose lipopolysaccharide (LPS; 1 mg/kg, i.p.) or saline at 0, 6, and 24 …

Effects Of Phosphodiesterase 3a Modulation On Murine Cerebral Microhemorrhages, Rachita K. Sumbria, Vitaly Vasilevko, Mher Mahoney Grigoryan, Annlia Paganini-Hill, Ronald Kim, David H. Cribbs, Mark J. Fisher

Pharmacy Faculty Articles and Research

Background: Cerebral microbleeds (CMB) are MRI-demonstrable cerebral microhemorrhages (CMH) which commonly coexist with ischemic stroke. This creates a challenging therapeutic milieu, and a strategy that simultaneously protects the vessel wall and provides anti-thrombotic activity is an attractive potential approach. Phosphodiesterase 3A (PDE3A) inhibition is known to provide cerebral vessel wall protection combined with anti-thrombotic effects. As an initial step in the development of a therapy that simultaneously treats CMB and ischemic stroke, we hypothesized that inhibition of the PDE3A pathway is protective against CMH development.

Methods: The effect of PDE3A pathway inhibition was studied in the inflammation-induced and …

A Murine Model Of Inflammation-Induced Cerebral Microbleeds, Rachita K. Sumbria, Mher Mahoney Grigoryan, Vitaly Vasilevko, Tatiana B. Krasieva, Miriam Scadeng, Alexandra K. Dvornikova, Annlia Paganini-Hill, Ronald Kim, David H. Cribbs, Mark J. Fisher

Pharmacy Faculty Articles and Research

Background: Cerebral microhemorrhages (CMH) are tiny deposits of blood degradation products in the brain and are pathological substrates of cerebral microbleeds. The existing CMH animal models are β-amyloid-, hypoxic brain injury-, or hypertension-induced. Recent evidence shows that CMH develop independently of hypoxic brain injury, hypertension, or amyloid deposition and CMH are associated with normal aging, sepsis, and neurodegenerative conditions. One common factor among the above pathologies is inflammation, and recent clinical studies show a link between systemic inflammation and CMH. Hence, we hypothesize that inflammation induces CMH development and thus, lipopolysaccharide (LPS)-induced CMH may be an appropriate model to …