#643 Vitamin A status and in vitro immune responses in children with sickle cell disease

Vaso-occlusive events are the major source of morbidity and mortality in sickle cell disease (SCD); however, the pathogenic mechanisms driving these events remain unclear. Using hypoxia to induce pulmonary injury, we investigated mechanisms by which sickle hemoglobin increases susceptibility to lung injury in a murine model of SCD, where mice either exclusively express the human α/sickle β-globin (hαβS) transgene (SCD mice) or are heterozygous for the normal murine β-globin gene and express the hαβStransgene (mβ+/-, hαβS+/-; heterozygote SCD mice). Under normoxia, lungs from the SCD mice contained higher levels of xanthine oxidase (XO), nitrotyrosine, and cGMP than controls (C57BL/6 mice). Hypoxia increased XO and nitrotyrosine and decreased cGMP content in the lungs of all mice. After hypoxia, vascular congestion was increased in lungs with a greater content of XO and nitrotyrosine. Under normoxia, the association of heat shock protein 90 (HSP90) with endothelial nitric oxide synthase (eNOS) in lungs of SCD and heterozygote SCD mice was decreased compared with the levels of association in lungs of controls. Hypoxia further decreased association of HSP90 with eNOS in lungs of SCD and heterozygote SCD mice, but not in the control lungs. Pretreatment of rat pulmonary microvascular endothelial cells in vitro with xanthine/XO decreased A-23187-stimulated nitrite + nitrate production and HSP90 interactions with eNOS. These data support the hypotheses that hypoxia increases XO release from ischemic tissues and that the local increase in XO-induced oxidative stress can then inhibit HSP90 interactions with eNOS, decreasing ·NO generation and predisposing the lung to vaso-occlusion.

Download Full-text

Endothelial Barrier Integrity Is Disrupted In Vitro by Heme and by Serum From Sickle Cell Disease Patients

Frontiers in Immunology ◽

10.3389/fimmu.2020.535147 ◽

2020 ◽

Vol 11 ◽

Author(s):

Vanessa Araujo Gomes Santaterra ◽

Maiara Marx Luz Fiusa ◽

Bidossessi Wilfried Hounkpe ◽

Francine Chenou ◽

Wouitchekpo Vincent Tonasse ◽

...

Keyword(s):

Sickle Cell Disease ◽

Healthy Volunteers ◽

Sickle Cell ◽

Endothelial Barrier ◽

Acute Chest Syndrome ◽

Cell Disease ◽

Experimental Conditions ◽

Cell Monolayers ◽

Junction Protein

Free extracellular heme has been shown to activate several compartments of innate immunity, acting as a danger-associated molecular pattern (DAMP) in hemolytic diseases. Although localized endothelial barrier (EB) disruption is an important part of inflammation that allows circulating leukocytes to reach inflamed tissues, non-localized/deregulated disruption of the EB can lead to widespread microvascular hyperpermeability and secondary tissue damage. In mouse models of sickle cell disease (SCD), EB disruption has been associated with the development of a form of acute lung injury that closely resembles acute chest syndrome (ACS), and that can be elicited by acute heme infusion. Here we explored the effect of heme on EB integrity using human endothelial cell monolayers, in experimental conditions that include elements that more closely resemble in vivo conditions. EB integrity was assessed by electric cell-substrate impedance sensing in the presence of varying concentrations of heme and sera from SCD patients or healthy volunteers. Heme caused a dose-dependent decrease of the electrical resistance of cell monolayers, consistent with EB disruption, which was confirmed by staining of junction protein VE-cadherin. In addition, sera from SCD patients, but not from healthy volunteers, were also capable to induce EB disruption. Interestingly, these effects were not associated with total heme levels in serum. However, when heme was added to sera from SCD patients, but not from healthy volunteers, EB disruption could be elicited, and this effect was associated with hemopexin serum levels. Together our in vitro studies provide additional support to the concept of heme as a DAMP in hemolytic conditions.

Download Full-text

Mineral Content and Antisickling Activity of Annona senegalensis, Alchornea cordifolia and Vigna unguiculata Used in the Management of Sickle Cell Disease in the Kwilu Province (Congo, DR)

International Blood Research & Reviews ◽

10.9734/ibrr/2020/v11i330131 ◽

2020 ◽

pp. 18-27

Author(s):

Jules M. Kitadi ◽

Clément L. Inkoto ◽

Emmanuel M. Lengbiye ◽

Damien S. T. Tshibangu ◽

Dorothée D. Tshilanda ◽

...

Keyword(s):

Sickle Cell Disease ◽

Mineral Composition ◽

Sickle Cell ◽

Mineral Elements ◽

Spectrometric Method ◽

Spectrometric Analysis ◽

Composition Analysis ◽

Cell Disease ◽

Republic Of The Congo

Aims: To determine the mineral composition of some plants (Annona senegalensis Pers., Alchornea cordifolia (Schumach. & Thonn.) Müll. Arg. and Vigna unguiculate (L.) Walp.) used in the management of sickle cell disease by traditional practitioners in Kwilu province and to evaluate their antisickling activity in vitro. Study Design: Plant collection in the Kwilu province, sample preparation, antisickling tests and fluorescence spectrometric analysis. Place and Duration of Study: This work was performed at the Faculty of Science, University of Kinshasa, Congo DR, from October 2016 to January 2018. Methodology: These three plants were harvested in the province of Kwilu in Democratic Republic of the Congo. The mineral composition analysis was carried out using the fluorescence spectrometric method while the in vitro antisickling activity was evaluate using Emmel and hemolysis tests. Results: Twenty three mineral elements were identified in each of these three plants: Potassium (K), Phosphorus (P), Calcium (Ca), Sodium (Na), Magnesium (Mg), Sulphur (S), Chlorine (Cl) and trace elements as: Aluminum (Al), Silicon (Si), Vanadium (V), Chromium (Cr), Manganese (Mn), Iron (Fe), Nickel (Ni), Copper (Cu), Zinc (Zn), Selenium (Se), Brome (Br), Molybdenum (Mo), Tin (Sn), Iodine (I), Barium (Ba) and Lead (Pb). Annona senegalensis Pers., Alchornea cordifolia (Schumach. & Thonn.) Müll.Arg. and Vigna unguiculate (L.) Walp. aqueous extracts showed the capacity to prevent the sickling and the hemolysis of red blood cells. Conclusion: The obtained results confirm the antisickling activity thus justifying the use of these plants in Traditional Medicine for the management of sickle cell disease. The presence of some mineral elements like Fe, Zn, Mg and Se are useful for sickle cell disease patients.

Download Full-text

In vivo survival studies of 51Cr-labeled methyl acetimidate treated erythrocytes in patients with sickle cell disease

Blood ◽

10.1182/blood.v56.6.1041.1041 ◽

1980 ◽

Vol 56 (6) ◽

pp. 1041-1047 ◽

Cited By ~ 5

Author(s):

TG Gabuzda ◽

TL Chao ◽

MR Berenfeld ◽

T Gelbart

Keyword(s):

Sickle Cell Disease ◽

Survival Time ◽

Sickle Cell ◽

Clinical Testing ◽

Cell Disease ◽

Show Evidence ◽

Survival Studies ◽

Circulating Antibody

Abstract Studies of the survival time of 51Cr labeled erythrocytes treated in vitro with methyl acetimidate (MAI) were conducted in 13 patients with sickle cell disease in order to assess the suitability of this antisickling agent for more extensive clinical testing. In comparison with previously measured control values (average t1/2 8.4 +/- 1.1 days a), the survival time of the treated erythrocytes in 10 of the patients who were not transfused was initially prolonged (average t1/2 24.4 +/- 4.6 days). However, 5 of the 13 patients studied developed circulating antibody against the MAI treated erythrocytes, markedly reducing the survival time of MAI treated erythrocytes in subsequent studies. Two patients, each challenged 3 times with infused MAI treated erythrocytes, failed to show evidence of antibody production, suggesting that not all subjects become immunized even after repeated exposure. In spite of many other promising properties of MAI as an antisickling agent of potential value, consideration of its use in further clinical testing must depend on successful avoidance of immunization in patients receiving infusions of treated erythrocytes.

Download Full-text

Placenta growth factor in sickle cell disease: association with hemolysis and inflammation

Blood ◽

10.1182/blood-2009-04-217950 ◽

2010 ◽

Vol 115 (10) ◽

pp. 2014-2020 ◽

Cited By ~ 35

Author(s):

Julia E. Brittain ◽

Ben Hulkower ◽

Susan K. Jones ◽

Dell Strayhorn ◽

Laura De Castro ◽

...

Keyword(s):

Growth Factor ◽

Sickle Cell Disease ◽

Sickle Cell ◽

Predictive Accuracy ◽

Cross Sectional Study ◽

Acute Chest Syndrome ◽

Cell Disease ◽

Placenta Growth Factor ◽

Cross Sectional

Abstract Placenta growth factor (PlGF) is released by immature erythrocytes and is elevated in sickle cell disease (SCD). Previous data generated in vitro suggest that PlGF may play a role in the pathophysiology of SCD-associated pulmonary hypertension (PHT) by inducing the release of the vasoconstrictor, endothelin-1. In this cross-sectional study of 74 patients with SCD, we confirm that PlGF is significantly elevated in SCD compared with healthy control subjects. We found significantly higher levels of PlGF in SCD patients with PHT but observed no association of PlGF with the frequency of acute pain episodes or history of acute chest syndrome. The observed correlation between PlGF and various measures of red cell destruction suggests that hemolysis, and the resultant erythropoietic response, results in the up-regulation of PlGF. Although relatively specific, PlGF, as well as N-terminal pro-brain natriuretic peptide and soluble vascular cell adhesion molecule, has low predictive accuracy for the presence of PHT. Prospective studies are required to conclusively define the contribution of PlGF to the pathogenesis of PHT and other hemolytic complications in SCD.

Download Full-text