ARTICLE | doi:10.20944/preprints201907.0355.v1
Subject: Keywords: blood lead; plasmodium malaria parasites; anemia; free erythrocytes protoporphyrin
Online: 31 July 2019 (11:52:32 CEST)
Lead pollutants mainly from urban agricultural practices, Leaded paints, Leaded fuels spillages, Lead-contaminated air, soils, and water sources pause a health threat to urban children in Uganda. Prolonged Lead exposure affects iron metabolism, by competitively blocking iron absorption leading to anemia. Blood Lead (BL) inhibits key enzymes ferrochelatase and aminolevulinic acid dehydrogenase (ALAD) involved in hemoglobin (Hb) biosynthesis even at very low levels. Lead poisoning and malaria infection geographically overlap, and both produce similar hematological outcome especially in children. Malaria parasites cause anemia by destroying parasitized red blood cells, therefore, co-existence of BL and malaria parasites infection worsens the anemia status of the host. This study aimed at expounding the extent of heme synthesis inhibition by BL levels among a study group of malaria positive children by measuring levels of free erythrocyte protoporphyrin (FEP) in blood samples. Briefly venous blood samples from 198 children were analyzed for malaria parasite densities by the thick smear method, hemoglobin (Hb) concentrations determined by the standard cyan methemoglobin method, BLL were analyzed on an atomic absorption spectrophotometer and FEP levels were fluorometrically measured. The results showed means of BLL (9.3 µg/dL), Hb (7.5 g/dL), FEP/Hb (8.3 µg/g) and parasite density (PD) (3.21×103 parasites / µL) among the study group. A majority of 151/198 (76.3%) of the children were moderately anemic while 8/198 (4%) were severely anemic. There was weak correlation between PD and Hb (R²= -0.15, P-value < 0.001), as compared to one between FEP/Hb and Hb (R²= -0.6, P-value=0.001). The study concludes that BL is a significant contributor to malaria anemia and should be considered in the management of anemia in malaria-endemic areas.
REVIEW | doi:10.20944/preprints202101.0193.v1
Subject: Life Sciences, Biochemistry Keywords: gasotransmitters; hydrogen sulfide; cardiovascular system; circulation; hemostasis; erythrocytes; therapeutic potential.
Online: 11 January 2021 (12:48:43 CET)
this review summarizes current knowledge of the hydrogen sulfide role in cardiovascular system, the proposed mechanisms of its action and the prospects for its applicability in the treatment of cardiovascular diseases. Hydrogen sulfide was recently recognized as gasotransmitter – simple signaling molecule which freely penetrates the cell membrane and regulates a number of biological functions. In humans endogenous H2S is generated via enzymatic and non-enzymatic pathways and its content varies in different tissues and is strictly regulated. In cardiovascular system H2S is produced by myocardial, vascular and blood cells and regulates a number of vital functions. Numerous experimental data prove that endogenously generated as well as exogenously administered H2S exerts a wide range of actions in cardiovascular system, including vasodilator/vasoconstrictor effects, regulation of blood pressure, pro-apoptotic and anti-proliferative effects in the vascular smooth muscle cells, influence on angiogenesis and erythropoiesis, myocardial cytoprotection in ischemia-reperfusion injury, oxygen sensing, inhibition of platelet aggregation and blood coagulation, modification of erythrocyte microrheological properties (aggregability and deformability). Understanding of molecular mechanisms of H2S action and molecular crosstalk between H2S, NO, and CO is essential for the development of its diagnostic and therapeutic potential.
ARTICLE | doi:10.20944/preprints202008.0717.v1
Subject: Biology, Physiology Keywords: erythrocytes; microvesicles; oxidative stress; band 3; t-BOOH; A23187; SNC
Online: 31 August 2020 (09:40:04 CEST)
Extracellular vesicles (EVs) released by different cell types play significant role in many physiological and pathophysiological processes. In physiological conditions red blood cells (RBCs) derived EVs compose 4 - 8% of all circulating EVs, and oxidative stress (OS) as a consequence of different pathophysiological conditions significantly increases the amount of circulated RBC-derived EVs, however the mechanisms of EV formation are not fully defined yet. To analyze OS-induced EV formation and RBCs transformations we used flow cytometry to evaluate cell esterase activity, caspase-3 activity, and band 3 clustering. Band 3 clustering was additionally analyzed by confocal microscopy. Two original laser diffraction-based approaches were used for analysis of cell deformability and band 3 activity. Hemoglobin species were characterized spectrophotometrically. We showed that cell viability in tert-butyl hydroperoxide-induced OS directly correlated with oxidant concentration to cell count ratio, RBCs-derived EVs contained hemoglobin oxidized to hemichrome (HbChr). OS induced caspase-3 activation and band 3 clustering in cells and EVs. Importantly, we showed that OS-induced EV formation is independent from calcium. Presented data indicated that during OS RBCs eliminate HbChr by vesiculation, in order to sacrifice the cell itself thereby prolonging lifespan and delaying the untimely clearance of in all other respects healthy RBCs.
ARTICLE | doi:10.20944/preprints201809.0414.v1
Subject: Chemistry, Food Chemistry Keywords: Sweet cherry; Anthocyanins; Non-coloured phenolics; Antioxidant activity; Erythrocytes protection; Caco-2 cells.
Online: 20 September 2018 (14:23:18 CEST)
This study aimed to compare three different extracts of Saco sweet cherry, namely non-coloured fraction, coloured fraction and total extract concerning phenolic composition, antioxidant and antidiabetic potential, erythrocytes’ protection and effects on Caco-2 cells. A total of 22 phenolic compounds were identified by LC-DAD. Hydroxycinnamic acids were the most predominant in both non-coloured fraction and total extract, while cyanidin-3-O-rutinoside was the main anthocyanin found in the coloured fraction. The total extract was the most effective against DPPH, nitric oxide and superoxide radicals, and in the inhibition of α-glucosidase enzyme. Finally, the protective effect of the extracts to prevent oxidative damage in human erythrocytes was assessed. The coloured fraction revealed the best activity against hemoglobin oxidation and hemolysis. Regarding to Caco-2 cells, the coloured extract exhibited the most cytotoxic effects, while the total extract was the most efficient in protecting these cells against oxidative damage induced by t-BHP.