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Differential cerebral hemometabolic responses to blood transfusions in adults and children with sickle cell anemia.
Juttukonda MR, Lee CA, Patel NJ, Davis LT, Waddle SL, Gindville MC, Pruthi S, Kassim AA, DeBaun MR, Donahue MJ, Jordan LC
(2019) J Magn Reson Imaging 49: 466-477
MeSH Terms: Adolescent, Adult, Age Factors, Anemia, Sickle Cell, Blood Transfusion, Brain, Cerebrovascular Circulation, Child, Female, Hematocrit, Hemodynamics, Humans, Longitudinal Studies, Magnetic Resonance Imaging, Male, Oximetry, Oxygen, Oxygen Consumption, Pain Management, Prospective Studies, Recurrence, Stroke, Young Adult
Show Abstract · Added March 24, 2020
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 T -weighted, T -weighted, and T -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.
© 2018 International Society for Magnetic Resonance in Medicine.
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Automated quantification of microvascular perfusion.
McClatchey PM, Mignemi NA, Xu Z, Williams IM, Reusch JEB, McGuinness OP, Wasserman DH
(2018) Microcirculation 25: e12482
MeSH Terms: Animals, Automation, Blood Flow Velocity, Hematocrit, Mice, Microcirculation, Microscopy, Fluorescence, Microscopy, Video, Microvessels, Perfusion, Phenylephrine, Reproducibility of Results, Saline Solution, Software
Show Abstract · Added March 26, 2019
OBJECTIVE - Changes in microvascular perfusion have been reported in many diseases, yet the functional significance of altered perfusion is often difficult to determine. This is partly because commonly used techniques for perfusion measurement often rely on either indirect or by-hand approaches.
METHODS - We developed and validated a fully automated software technique to measure microvascular perfusion in videos acquired by fluorescence microscopy in the mouse gastrocnemius. Acute perfusion responses were recorded following intravenous injections with phenylephrine, SNP, or saline.
RESULTS - Software-measured capillary flow velocity closely correlated with by-hand measured flow velocity (R = 0.91, P < 0.0001). Software estimates of capillary hematocrit also generally agreed with by-hand measurements (R = 0.64, P < 0.0001). Detection limits range from 0 to 2000 μm/s, as compared to an average flow velocity of 326 ± 102 μm/s (mean ± SD) at rest. SNP injection transiently increased capillary flow velocity and hematocrit and made capillary perfusion more steady and homogenous. Phenylephrine injection had the opposite effect in all metrics. Saline injection transiently decreased capillary flow velocity and hematocrit without influencing flow distribution or stability. All perfusion metrics were temporally stable without intervention.
CONCLUSIONS - These results demonstrate a novel and sensitive technique for reproducible, user-independent quantification of microvascular perfusion.
© 2018 John Wiley & Sons Ltd.
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14 MeSH Terms
Exome Genotyping Identifies Pleiotropic Variants Associated with Red Blood Cell Traits.
Chami N, Chen MH, Slater AJ, Eicher JD, Evangelou E, Tajuddin SM, Love-Gregory L, Kacprowski T, Schick UM, Nomura A, Giri A, Lessard S, Brody JA, Schurmann C, Pankratz N, Yanek LR, Manichaikul A, Pazoki R, Mihailov E, Hill WD, Raffield LM, Burt A, Bartz TM, Becker DM, Becker LC, Boerwinkle E, Bork-Jensen J, Bottinger EP, O'Donoghue ML, Crosslin DR, de Denus S, Dubé MP, Elliott P, Engström G, Evans MK, Floyd JS, Fornage M, Gao H, Greinacher A, Gudnason V, Hansen T, Harris TB, Hayward C, Hernesniemi J, Highland HM, Hirschhorn JN, Hofman A, Irvin MR, Kähönen M, Lange E, Launer LJ, Lehtimäki T, Li J, Liewald DC, Linneberg A, Liu Y, Lu Y, Lyytikäinen LP, Mägi R, Mathias RA, Melander O, Metspalu A, Mononen N, Nalls MA, Nickerson DA, Nikus K, O'Donnell CJ, Orho-Melander M, Pedersen O, Petersmann A, Polfus L, Psaty BM, Raitakari OT, Raitoharju E, Richard M, Rice KM, Rivadeneira F, Rotter JI, Schmidt F, Smith AV, Starr JM, Taylor KD, Teumer A, Thuesen BH, Torstenson ES, Tracy RP, Tzoulaki I, Zakai NA, Vacchi-Suzzi C, van Duijn CM, van Rooij FJ, Cushman M, Deary IJ, Velez Edwards DR, Vergnaud AC, Wallentin L, Waterworth DM, White HD, Wilson JG, Zonderman AB, Kathiresan S, Grarup N, Esko T, Loos RJ, Lange LA, Faraday N, Abumrad NA, Edwards TL, Ganesh SK, Auer PL, Johnson AD, Reiner AP, Lettre G
(2016) Am J Hum Genet 99: 8-21
MeSH Terms: African Americans, Allelic Imbalance, Erythrocyte Indices, Erythrocytes, Erythropoiesis, Exome, Gene Frequency, Genetic Pleiotropy, Genetic Variation, Genotype, Hematocrit, Hemoglobins, Humans, Quantitative Trait Loci
Show Abstract · Added April 26, 2017
Red blood cell (RBC) traits are important heritable clinical biomarkers and modifiers of disease severity. To identify coding genetic variants associated with these traits, we conducted meta-analyses of seven RBC phenotypes in 130,273 multi-ethnic individuals from studies genotyped on an exome array. After conditional analyses and replication in 27,480 independent individuals, we identified 16 new RBC variants. We found low-frequency missense variants in MAP1A (rs55707100, minor allele frequency [MAF] = 3.3%, p = 2 × 10(-10) for hemoglobin [HGB]) and HNF4A (rs1800961, MAF = 2.4%, p < 3 × 10(-8) for hematocrit [HCT] and HGB). In African Americans, we identified a nonsense variant in CD36 associated with higher RBC distribution width (rs3211938, MAF = 8.7%, p = 7 × 10(-11)) and showed that it is associated with lower CD36 expression and strong allelic imbalance in ex vivo differentiated human erythroblasts. We also identified a rare missense variant in ALAS2 (rs201062903, MAF = 0.2%) associated with lower mean corpuscular volume and mean corpuscular hemoglobin (p < 8 × 10(-9)). Mendelian mutations in ALAS2 are a cause of sideroblastic anemia and erythropoietic protoporphyria. Gene-based testing highlighted three rare missense variants in PKLR, a gene mutated in Mendelian non-spherocytic hemolytic anemia, associated with HGB and HCT (SKAT p < 8 × 10(-7)). These rare, low-frequency, and common RBC variants showed pleiotropy, being also associated with platelet, white blood cell, and lipid traits. Our association results and functional annotation suggest the involvement of new genes in human erythropoiesis. We also confirm that rare and low-frequency variants play a role in the architecture of complex human traits, although their phenotypic effect is generally smaller than originally anticipated.
Copyright © 2016 American Society of Human Genetics. All rights reserved.
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14 MeSH Terms
Shear stress is normalized in glomerular capillaries following ⅚ nephrectomy.
Ferrell N, Sandoval RM, Bian A, Campos-Bilderback SB, Molitoris BA, Fissell WH
(2015) Am J Physiol Renal Physiol 308: F588-93
MeSH Terms: Animals, Blood Pressure, Capillaries, Hematocrit, Hemorheology, Kidney Glomerulus, Male, Nephrectomy, Rats, Wistar, Renal Circulation, Renal Insufficiency, Stress, Mechanical
Show Abstract · Added February 22, 2016
Loss of significant functional renal mass results in compensatory structural and hemodynamic adaptations in the nephron. While these changes have been characterized in several injury models, how they affect hemodynamic forces at the glomerular capillary wall has not been adequately characterized, despite their potential physiological significance. Therefore, we used intravital multiphoton microscopy to measure the velocity of red blood cells in individual glomerular capillaries of normal rats and rats subjected to ⅚ nephrectomy. Glomerular capillary blood flow rate and wall shear stress were then estimated using previously established experimental and mathematical models to account for changes in hematocrit and blood rheology in small vessels. We found little change in the hemodynamic parameters in glomerular capillaries immediately following injury. At 2 wk postnephrectomy, significant changes in individual capillary blood flow velocity and volume flow rate were present. Despite these changes, estimated capillary wall shear stress was unchanged. This was a result of an increase in capillary diameter and changes in capillary blood rheology in nephrectomized rats.
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Genetic variants that confer resistance to malaria are associated with red blood cell traits in African-Americans: an electronic medical record-based genome-wide association study.
Ding K, de Andrade M, Manolio TA, Crawford DC, Rasmussen-Torvik LJ, Ritchie MD, Denny JC, Masys DR, Jouni H, Pachecho JA, Kho AN, Roden DM, Chisholm R, Kullo IJ
(2013) G3 (Bethesda) 3: 1061-8
MeSH Terms: African Americans, Disease Resistance, Electronic Health Records, Erythrocyte Count, Erythrocyte Indices, Erythrocytes, Genome-Wide Association Study, Hematocrit, Hemoglobins, Humans, Malaria
Show Abstract · Added March 7, 2014
To identify novel genetic loci influencing interindividual variation in red blood cell (RBC) traits in African-Americans, we conducted a genome-wide association study (GWAS) in 2315 individuals, divided into discovery (n = 1904) and replication (n = 411) cohorts. The traits included hemoglobin concentration (HGB), hematocrit (HCT), RBC count, mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), and mean corpuscular hemoglobin concentration (MCHC). Patients were participants in the electronic MEdical Records and GEnomics (eMERGE) network and underwent genotyping of ~1.2 million single-nucleotide polymorphisms on the Illumina Human1M-Duo array. Association analyses were performed adjusting for age, sex, site, and population stratification. Three loci previously associated with resistance to malaria-HBB (11p15.4), HBA1/HBA2 (16p13.3), and G6PD (Xq28)-were associated (P ≤ 1 × 10(-6)) with RBC traits in the discovery cohort. The loci replicated in the replication cohort (P ≤ 0.02), and were significant at a genome-wide significance level (P < 5 × 10(-8)) in the combined cohort. The proportions of variance in RBC traits explained by significant variants at these loci were as follows: rs7120391 (near HBB) 1.3% of MCHC, rs9924561 (near HBA1/A2) 5.5% of MCV, 6.9% of MCH and 2.9% of MCHC, and rs1050828 (in G6PD) 2.4% of RBC count, 2.9% of MCV, and 1.4% of MCH, respectively. We were not able to replicate loci identified by a previous GWAS of RBC traits in a European ancestry cohort of similar sample size, suggesting that the genetic architecture of RBC traits differs by race. In conclusion, genetic variants that confer resistance to malaria are associated with RBC traits in African-Americans.
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Comparison of Impella and intra-aortic balloon pump in high-risk percutaneous coronary intervention: vascular complications and incidence of bleeding.
Boudoulas KD, Pederzolli A, Saini U, Gumina RJ, Mazzaferri EL, Davis M, Bush CA, Capers Q, Magorien R, Pompili VJ
(2012) Acute Card Care 14: 120-4
MeSH Terms: Acute Coronary Syndrome, Aged, Blood Transfusion, Coronary Stenosis, Female, Gastrointestinal Hemorrhage, Heart-Assist Devices, Hematocrit, Hemodynamics, Hemorrhage, Hospital Mortality, Humans, Intra-Aortic Balloon Pumping, Male, Middle Aged, Retrospective Studies
Show Abstract · Added February 21, 2015
OBJECTIVE - Compare vascular complications and incidence of bleeding of Impella 2.5 and intra-aortic balloon pump (IABP) in high-risk percutaneous coronary interventions (PCI).
BACKGROUND - Large arterial sheath size for device insertion is associated with vascular and/or bleeding complications; gastrointestinal bleeding may also occur with anti-coagulation use.
METHODS - Patients with an acute coronary syndrome receiving Impella 2.5 or IABP during high-risk PCI were studied (13 Impella; 62 IABP). Vascular complications and incidence of bleeding were compared.
RESULTS - Post-procedure hematocrit was similar between groups. Blood transfusion occurred in 38.4% and 32.2% of patients in the Impella and IABP groups, respectively (P = NS); 65.3%, 30.7% and 3.8% of bleeding were due to vascular access site/procedure related, gastrointestinal and genitourinary, respectively. There was no statistical significant difference in vascular complications between the Impella and IABP groups (15.3% and 6.4% of patients, respectively); mesenteric ischemia (n = 1) and aortic rupture (n = 1) were only in the IABP group. In-hospital and one-year mortality were not statistically significant between groups.
CONCLUSION - Impella can be used as safely as IABP during high-risk PCI with similar vascular and bleeding complications. Importantly, approximately one third of bleeding was from the gastrointestinal system warranting careful prophylactic measures and monitoring.
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Comparative effects of angiotensin receptor blockade and ACE inhibition on the fibrinolytic and inflammatory responses to cardiopulmonary bypass.
Billings FT, Balaguer JM, C Y, Wright P, Petracek MR, Byrne JG, Brown NJ, Pretorius M
(2012) Clin Pharmacol Ther 91: 1065-73
MeSH Terms: Aged, Angiotensin II Type 1 Receptor Blockers, Angiotensin-Converting Enzyme Inhibitors, Benzimidazoles, Blood Transfusion, Bradykinin, Cardiopulmonary Bypass, Endpoint Determination, Female, Fibrinolysis, Hematocrit, Hospital Mortality, Humans, Inflammation, Interleukins, Length of Stay, Male, Middle Aged, Monitoring, Intraoperative, Perioperative Care, Postoperative Complications, Ramipril, Tetrazoles, Treatment Outcome
Show Abstract · Added December 10, 2013
The effects of angiotensin-converting enzyme (ACE) inhibition and angiotensin II type 1 receptor blockade (ARB) on fibrinolysis and inflammation after cardiopulmonary bypass (CPB) are uncertain. This study tested the hypothesis that ACE inhibition enhances fibrinolysis and inflammation to a greater extent than ARB in patients undergoing CPB. One week to 5 days before surgery, patients were randomized to ramipril 5 mg/day, candesartan 16 mg/day, or placebo. ACE inhibition increased intraoperative bradykinin and tissue-type plasminogen activator (t-PA ) concentrations as compared to AR B. Both ACE inhibition and AR B decreased the need for plasma transfusion relative to placebo, but only ACE inhibition decreased the duration of hospital stay. Neither ACE inhibition nor AR B significantly affected concentrations of plasminogen activator inhibitor-1 (PAI -1), interleukin (IL )-6, IL -8, or IL -10. ACE inhibition enhanced intraoperative fibrinolysis without increasing the likelihood of red-cell transfusion. By contrast, neither ACE inhibition nor ARB affected the inflammatory response. ACE inhibitors and ARBs may be safely continued until the day of surgery.
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Dose-dependent treatment of optic nerve crush by exogenous systemic mutant erythropoietin.
Sullivan TA, Geisert EE, Templeton JP, Rex TS
(2012) Exp Eye Res 96: 36-41
MeSH Terms: Animals, Cell Count, Cytomegalovirus, Dependovirus, Disease Models, Animal, Dose-Response Relationship, Drug, Enzyme-Linked Immunosorbent Assay, Erythropoietin, Genetic Vectors, Glaucoma, Green Fluorescent Proteins, Hematocrit, Injections, Intramuscular, Mice, Mice, Inbred BALB C, Nerve Crush, Optic Nerve Injuries, Recombinant Fusion Proteins, Retinal Ganglion Cells
Show Abstract · Added January 20, 2015
The goal of the present study was to determine the minimum concentration of systemic erythropoietin-R76E required for neuroprotection in the retina. Erythropoietin (EPO) exhibits neuroprotective effects in both in vitro and in vivo models of neuronal cell death although its classical function is the regulation of red blood cell production. It can cross the blood brain barrier and therefore can be delivered systemically to affect the retina. However, long-term treatment with exogenous erythropoietin causes polycythemia. To decrease this potentially lethal effect, we generated and tested a modified form that contains a single arginine to glutamate mutation at the 76th position (EPO-R76E). In previous studies, this mutant protected retinal neurons in mouse models of retinal degeneration and glaucoma with similar efficacy as wild-type EPO. However, EPO-R76E has attenuated erythropoietic activity, therefore, neuroprotection can be achieved without causing a significant rise in hematocrit. BALB/cByJ mice received a single intramuscular injection of recombinant adeno-associated virus carrying enhanced green fluorescent protein, Epo, or Epo-R76E. To result in continuous production of four different doses of EPO-R76E, two doses of two different serotypes (2/5 and 2/8) were used. Mice were subjected to optic nerve crush and analysis was performed thirty days later. EPO-R76E showed dose-dependent protection of the retinal ganglion cell bodies, but was unable to prevent axonal degeneration. Furthermore, EPO-R76E induced a dose-dependent rise in the hematocrit that was still attenuated as compared to wild-type EPO.
Copyright © 2012 Elsevier Ltd. All rights reserved.
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Usefulness of the blood hematocrit level to predict development of heart failure in a community.
Coglianese EE, Qureshi MM, Vasan RS, Wang TJ, Moore LL
(2012) Am J Cardiol 109: 241-5
MeSH Terms: Aged, Disease Progression, Female, Follow-Up Studies, Heart Failure, Hematocrit, Humans, Incidence, Male, Middle Aged, Prognosis, Prospective Studies, Time Factors, United States
Show Abstract · Added April 15, 2014
Current data suggest that increases in hemoglobin may decrease nitric oxide and adversely affect vascular function. In the preclinical setting, these changes could precipitate the development of heart failure (HF). We hypothesized that higher hematocrit (HCT) would be associated with an increased incidence of new-onset HF in the community. We evaluated 3,523 participants (59% women) from the Framingham Heart Study who were 50 to 65 years old and free of HF. Participants were followed prospectively until an HF event, death, or the end of 20 years of follow up. HCT was subdivided into 4 gender-specific categories (women: HCT 36.0 to 40.0, 40.1 to 42.0, 42.1 to 45.0, >45.0; men: 39.0 to 44.0, 44.1 to 45.0, 45.1 to 49.0, >49.0). Gender-pooled multivariable Cox proportional hazards models were used to estimate the association of HCT with incident HF, adjusting for clinical risk factors. During the follow-up period (61,417 person-years), 217 participants developed HF (100 events in women). There was a linear increase in risk of HF across the 4 HCT categories (p for trend = 0.002). Hazards ratios for HF in the low-normal, normal, and high HCT categories were 1.27 (95% confidence interval 0.82 to 1.97), 1.47 (1.01 to 2.15), and 1.78 (1.15 to 2.75), respectively, compared to the lowest HCT category (p for trend <0.0001). Adjustment for interim development of other cardiovascular diseases and restriction of the sample to nonsmokers did not alter the results. In conclusion, higher levels of HCT, even within the normal range, were associated with an increased risk of developing HF in this long-term follow-up study.
Copyright © 2012 Elsevier Inc. All rights reserved.
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Systemic adeno-associated virus-mediated gene therapy preserves retinal ganglion cells and visual function in DBA/2J glaucomatous mice.
Sullivan TA, Geisert EE, Hines-Beard J, Rex TS
(2011) Hum Gene Ther 22: 1191-200
MeSH Terms: Analysis of Variance, Animals, Axons, Dependovirus, Enzyme-Linked Immunosorbent Assay, Erythropoietin, Evoked Potentials, Visual, Genetic Therapy, Genetic Vectors, Glaucoma, Hematocrit, Immunohistochemistry, Injections, Intramuscular, Macaca mulatta, Mice, Mice, Inbred DBA, Mutation, Missense, Optic Nerve, Retinal Ganglion Cells, Vision, Ocular
Show Abstract · Added January 20, 2015
A slow progressive death of neurons is the hallmark of neurodegenerative diseases, such as glaucoma. A therapeutic candidate, erythropoietin (EPO), has shown promise in many models of these diseases; however, it also causes polycythemia, a potentially lethal side effect. We have developed a novel mutant form of EPO that is neuroprotective but no longer erythropoietic by altering a single amino acid (arginine to glutamate at position 76; R76E). We hypothesized that a single intramuscular injection of recombinant adeno-associated virus carrying EpoR76E (rAAV2/5.CMV.EpoR76E) would protect retinal ganglion cells in a mouse model of glaucoma without inducing polycythemia. This systemic treatment not only protected the retinal ganglion cell somata located within the retina; it also preserved axonal projections within the optic nerve, while maintaining the hematocrit within normal limits. The rescued retinal ganglion cells retained their visual function demonstrated by flash visual evoked potentials. To our knowledge, this is the first demonstration of a therapy that protects neurons from death and prevents loss of visual function from the slow neurodegenerative effects of glaucoma. Because of its broad range of cellular targets, EpoR76E is likely to be successful in treating other neurodegenerative diseases as well.
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20 MeSH Terms