Asymmetric Dimethylarginine Levels and Its Correlation to Cerebral Blood Flow in Children with Sickle Cell Anemia.
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SUBMITTER: El-Shanshory M
PROVIDER: S-EPMC6825090 | biostudies-literature | 2019 Oct
REPOSITORIES: biostudies-literature
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Asymmetric Dimethylarginine Levels and Its Correlation to Cerebral Blood Flow in Children with Sickle Cell Anemia.
El-Shanshory Mohamed M Hablas Nahed N Nagy Hala H Fathy Naglaa N
Indian journal of hematology & blood transfusion : an official journal of Indian Society of Hematology and Blood Transfusion 20190313 4
Asymmetric dimethylarginine (ADMA) level may play a role in the pathogenesis of cerebrovascular stroke in Children with Sickle Cell Anemia (SCA). To assess the plasma level of ADMA in children with SCA and its correlation to cerebral blood flow. This is a cross sectional study was carried out on 30 children with homozygous SCA under follow up in the Out Patients Clinic, Pediatric Department at Tanta University Hospital and 30 healthy children as a control group. Both groups had undergone the fol ...[more]
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Project description:Prior studies have described high venous signal qualitatively using arterial spin labelling (ASL) in patients with sickle cell anemia (SCA), consistent with arteriovenous shunting. We aimed to quantify the effect and explored cross-sectional associations with arterial oxygen content (CaO2), disease-modifying treatments, silent cerebral infarction (SCI), and cognitive performance. 94 patients with SCA and 42 controls underwent cognitive assessment and MRI with single- and multi- inflow time (TI) ASL sequences. Cerebral blood flow (CBF) and bolus arrival time (BAT) were examined across gray and white matter and high-signal regions of the sagittal sinus. Across gray and white matter, increases in CBF and reductions in BAT were observed in association with reduced CaO2 in patients, irrespective of sequence. Across high-signal sagittal sinus regions, CBF was also increased in association with reduced CaO2 using both sequences. However, BAT was increased rather than reduced in patients across these regions, with no association with CaO2. Using the multiTI sequence in patients, increases in CBF across white matter and high-signal sagittal sinus regions were associated with poorer cognitive performance. These novel findings highlight the utility of multiTI ASL in illuminating, and identifying objectively quantifiable and functionally significant markers of, regional hemodynamic stress in patients with SCA.
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Project description:BACKGROUND:Blood transfusions are administered to children and adults with sickle cell anemia (SCA) for secondary stroke prevention, or as treatment for recurrent pain crises or acute anemia, but transfusion effects on cerebral hemodynamics and metabolism are not well-characterized. PURPOSE:To compare blood transfusion-induced changes in hemometabolic parameters, including oxygen extraction fraction (OEF) and cerebral blood flow (CBF), within and between adults and children with SCA. STUDY TYPE:Prospective, longitudinal study. SUBJECTS:Adults with SCA (n?=?16) receiving simple (n?=?7) or exchange (n?=?9) transfusions and children with SCA (n?=?11) receiving exchange transfusions were scanned once when hematocrit was near nadir and again within 7 days of transfusion. Adult controls without SCA or sickle trait (n?=?7) were scanned twice on separate days. FIELD STRENGTH/SEQUENCE:3.0T T1 -weighted, T2 -weighted, and T2 -relaxation-under-spin-tagging (TRUST) imaging, and phase contrast angiography. ASSESSMENT:Global OEF was computed as the relative difference between venous oxygenation (from TRUST) and arterial oxygenation (from pulse oximetry). Global CBF was computed as total blood flow to the brain normalized by intracranial tissue volume. STATISTICAL TESTS:Hemometabolic variables were compared using two-sided Wilcoxon signed-rank tests; associations were analyzed using two-sided Spearman's correlation testing. RESULTS:In adults with SCA, posttransfusion OEF?=?0.38?±?0.05 was lower (P?=?0.001) than pretransfusion OEF?=?0.45?±?0.09. A change in OEF was correlated with increases in hematocrit (P?=?0.02; rho?=?-0.62) and with pretransfusion hematocrit (P?=?0.02; rho?=?0.65). OEF changes after transfusion were greater (P?=?0.002) in adults receiving simple versus exchange transfusions. Posttransfusion CBF?=?77.7?±?26.4?ml/100g/min was not different (P?=?0.27) from pretransfusion CBF?=?82.3?±?30.2?ml/100g/min. In children with SCA, both posttransfusion OEF?=?0.28?±?0.04 and CBF?=?76.4?±?26.4 were lower than pretransfusion OEF?=?0.36?±?0.06 (P?=?0.004) and CBF?=?96.4?±?16.5 (P?=?0.004). DATA CONCLUSION:Cerebral OEF reduces following transfusions in adults and children with SCA. CBF reduces following transfusions more often in children compared to adults, indicating that vascular reserve capacity may remain near exhaustion posttransfusion in many adults. LEVEL OF EVIDENCE:2 Technical Efficacy Stage 5 J. Magn. Reson. Imaging 2019;49:466-477.
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Project description:BackgroundIrregular, sporadic episodes of ischemic brain injury are known to occur in sickle cell anemia (SCA), resulting in overt stroke and silent cerebral infarction. Ongoing ischemia in other organs is common in SCA but has never been documented in the brain.ObjectiveTo test the hypothesis that acute silent cerebral ischemic events (ASCIEs) are frequent and potentially transient.DesignCross-sectional and cohort study of children with SCA screened by magnetic resonance imaging (MRI) of the brain for a randomized clinical trial.SettingClinical trial setting in tertiary care centers.PatientsAsymptomatic children with SCA without known stroke, neurologic injury, or epilepsy not receiving treatment with transfusions or hydroxyurea.Main outcome measureIncidence of ASCIEs calculated using single diffusion-weighted MRI scans (acute ischemic events that occurred within 10 days of the MRI).ResultsAcute silent cerebral ischemic events were detected on 1.3% of MRIs (10 of 771) in 652 children (mean age, 10.0 years), with an incidence of 47.3 events per 100 patient-years (95% CI, 22.7-87.2). Two of 10 children with ASCIEs had follow-up MRIs of the brain; only 1 had silent cerebral infarction in the same location as the previously detected ASCIE.ConclusionsChildren with SCA experience ongoing (chronic, intermittent) cerebral ischemia, sometimes reversible, far more frequently than previously recognized. The brain in SCA is at constant threat of ischemia.
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