Browsing by Autor "Andrew S Lampert"

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Abstract 151: CD163 Has Distinct Temporal Influences on Intracerebral Hemorrhage Outcomes
(Lippincott Williams & Wilkins, 2017) Jenna L Leclerc; Andrew S Lampert; Claudia Loyola Amador; Brandon Schlackman; Terrie Vasilopolous; Pia Svendsen; Søren K. Moestrup; Sylvain Doré
Extracorpuscular hemoglobin (Hb)-induced toxicity following intracerebral hemorrhage (ICH) precipitates secondary brain damage and poor outcomes. CD163 is the Hb scavenger receptor with potent anti-inflammatory effects and CD163-positive macrophages/microglia accumulate in the brain with time post-ICH, yet no studies have investigated the role of CD163 after ICH. ICH was induced in wildtype and CD163 -/- mice and various anatomical and functional outcomes were temporally assessed by histology and neurobehavioral testing. Acutely, CD163 -/- mice have 33.2±4.5% (p<0.0001), 43.4±5.0% (p=0.0002), and 34.8±3.4% (p=0.0003) less lesion volume, hematoma volume, and tissue injury, respectively. Whereas, at 10d, CD163 -/- mice have 49.2±15.0% larger lesion volumes (p=0.0385). Temporal data inspection revealed an inflection point at 4d, where CD163 -/- mice perform significantly better on neurobehavioral testing and have less mortality before 4d, but increased mortality and worse function after 4d (p<0.05). Histology at 72h shows that CD163 -/- mice have significantly less Hb, iron, and blood-brain barrier dysfunction, increased astrogliosis and cortical neovascularization, and no change in HO1 expression. At 10d, CD163 -/- mice have increased iron and hematomal VEGF immunoreactivity, no change in HO1 expression, and decreased astrogliosis. These novel findings reveal that CD163 deficiency has distinct temporal influences on ICH outcomes, with early beneficial properties but delayed injurious effects. While it is unclear why CD163 deficiency is initially beneficial, the late injurious effects of absent CD163 are consistent with the key anti-inflammatory role of the receptor in the recovery phase of tissue damage. CD163 may represent a key targetable immunomodulatory receptor after ICH. Funding: This work was supported by NIH grants F31NS086441 (JLL) and R01NS046400 (SD).
Abstract WMP106: Haptoglobin is Present as Zonulin in the Brain and Overexpression Improves Intracerebral Hemorrhage Outcomes
(Lippincott Williams & Wilkins, 2019) Jenna L Leclerc; Andrew S Lampert; Harrison Phillips; Tina Esfandiary; Alex Dang; Juan Santiago‐Moreno; Sylvain Doré
Intracerebral hemorrhage (ICH) most commonly results from a hypertensive spontaneous bleed into the brain parenchyma and is a devastating stroke subtype. Hemolysis ensues and large quantities of hemoglobin (Hb) are released that initiate a toxic oxidative and neuroinflammatory cascade. Hp is an abundant plasma glycoprotein that binds and detoxifies extracorpuscular Hb with strong affinity, although very little Hp is made endogenously within the brain. Of note, Hp undergoes a complex biosynthesis into a single polypeptide prohaptoglobin that is co-translationally processed in the endoplasmic reticulum to form the α- and β-subunits, which subsequently dimerize. We hypothesized that overexpressing Hp locally in the brain would lead to improved outcomes following ICH. Overexpression was achieved using adeno-associated viral vectors and ICH was induced using the intrastriatal autologous whole blood injection model. Functional outcomes were assessed by a 24-point neurological deficit score. Western blotting under reducing and non-reducing conditions and mass spectrometry were utilized to confirm the identity of the overexpression product, which surprisingly was prohaptoglobin, also known as zonulin. At 72h post-ICH, zonulin-overexpressing mice have smaller lesion volumes with less blood accumulation and better neurologic function (p<0.05) when compared to controls (n=11-13/group). Zonulin-overexpressing mice also demonstrate less heme oxygenase-1 expression, lipid peroxidation, and peripheral neutrophil infiltration, and significantly increased microgliosis and astrogliosis. No differences in iron content were seen. Importantly, these results provide evidence that Hp in its fully processed form is not made endogenously within the brain, but instead transcription from this gene results in the formation of zonulin, which has very distinctly different functions. Notably, zonulin does not bind Hb or provide redox protection, but is a strong regulator of intercellular tight junctions, which has important implications for intracranial bleeding. Interestingly, we show that zonulin-overexpression improves ICH outcomes and thus this pathway represents a new potentially targetable avenue for the treatment of ICH.