Program: Oral and Poster Abstracts
Session: 113. Hemoglobinopathies, Excluding Thalassemia – Basic and Translational Science: Poster III
Methods: Townes sickle cell mice (SCD), homozygous for hα:βs-globulin, approximately 7−9 weeks of age (n=28), and control mice, homozygous for hα:β-globulin (n=11), were used in these studies. CEUS perfusion imaging (Vevo®2100) was performed on a central cross-section of the liver at the renal artery. Contrast agent was administered as an intravenous bolus via tail vein to anesthetized mice (isoflurane with ~21% O2); peak enhancement (PE) was analyzed with VisualSonics software. CEUS measurements were obtained at baseline and following either (1) hypoxia, 60 minutes with 5.5.% O2 followed by ~60 minutes of reoxygenation at room oxygen (~21% O2) or (2) normoxia, ~120 minutes at room oxygen. 5-HMF at 20 and 200 mg/kg PO or vehicle was administered following baseline PE measurement and approximately 30 minutes before start of hypoxia.
Results: MVLP in SCD (n=28) was significantly reduced by approximately 40% compared with controls (n=11) at baseline (PE of 14.0±0.7 linear arbitrary units [l.a.u.] vs. 23.6±2.1 l.a.u.), respectively, P<0.001 [Student t test]). Normoxic SCD maintained similar PE to baseline levels (Table 1); however, hypoxia significantly reduced MVLP by 49% in SCD mice. In contrast, hypoxia had no significant effect in control mice. 5-HMF at 20 and 200 mg/kg resulted in a dose-dependent increase in posthypoxia MVLP. 5-HMF at 200 mg/kg was not significantly different from baseline PE, and 5-HMF at 20 mg/kg increased MVLP by approximately 50% compared with the vehicle group posthypoxia (26% vs 49% reduction in MVLP, respectively). Pathologic evaluation of naive SCD formalin-fixed liver tissues (n=10) showed congestion, necrosis, hepatocellular hypertrophy, and extramedullary hematopoiesis.
Table 1. CEUS-Acquired Microvascular Liver Perfusion in SCD and Control Mice (mean ± SEM)
Strain |
Dose |
Oxygen Status |
Mice, n |
Baseline PE, l.a.u. |
Posthypoxia/Normoxia PE, l.a.u. |
Change From Baseline, % |
Control |
Vehicle |
Hypoxic |
11 |
23.6±2.1 |
22.1±2.1 |
–7 |
SCD |
Vehicle |
Normoxic |
4 |
14.0±2.1 |
13.3±1.6 |
–3 |
SCD |
Vehicle |
Hypoxic |
8 |
15.4 ±1.6 |
7.0±0.9* |
–49 |
SCD |
HMF, 20 mg/kg |
Hypoxic |
8 |
12.8±0.9 |
9.2±0.7* |
–26 |
SCD |
HMF, 200 mg/kg |
Hypoxic |
8 |
13.8±1.5 |
11.9±1.2 |
–12 |
*Statistically significant reduction compared with baseline PE (P<0.01, Student ttest).
Summary: CEUS measured lower basal levels of MVLP in SCD compared with control mice, which correlated with pathologic findings of congestion and necrosis in the livers of SCD mice. The hypoxia-induced VOC decrease in MVLP was present only in the SCD mice; no effect was observed in control mice. Treatment with the antisickling agent, 5-HMF, dose-dependently ameliorated the hypoxia-induced VOC decrease in MVLP in SCD mice. Based on these results, CEUS may be considered as a noninvasive method to measure acute and chronic organ perfusion changes for evaluating new therapeutics for sickle cell-mediated VOC events and end-organ damage.
Disclosures: Wright: Bayer HealthCare LLC: Employment . Sim: Bayer HealthCare LLC: Employment . Alonso-Galicia: Bayer HealthCare LLC: Employment . Kauser: Bayer HealthCare LLC: Employment . Abe: Bayer HealthCare LLC: Employment .
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