The role of Na+-coupled bicarbonate transporters (NCBT) in health and disease.

Cellular and organism survival depends upon the regulation of pH, which is regulated by highly specialized cell membrane transporters, the solute carriers (SLC) (For a comprehensive list of the solute carrier family members, see: https://www.bioparadigms.org/slc/ ). The SLC4 family of bicarbonate (HCO3-) transporters consists of ten members, sorted by their coupling to either sodium (NBCe1, NBCe2, NBCn1, NBCn2, NDCBE), chloride (AE1, AE2, AE3), or borate (BTR1). The ionic coupling of SLC4A9 (AE4) remains controversial. These SLC4 bicarbonate transporters may be controlled by cellular ionic gradients, cellular membrane voltage, and signaling molecules to maintain critical cellular and systemic pH (acid-base) balance. There are profound consequences when blood pH deviates even a small amount outside the normal range (7.35-7.45). Chiefly, Na+-coupled bicarbonate transporters (NCBT) control intracellular pH in nearly every living cell, maintaining the biological pH required for life. Additionally, NCBTs have important roles to regulate cell volume and maintain salt balance as well as absorption and secretion of acid-base equivalents. Due to their varied tissue expression, NCBTs have roles in pathophysiology, which become apparent in physiologic responses when their expression is reduced or genetically deleted. Variations in physiological pH are seen in a wide variety of conditions, from canonically acid-base related conditions to pathologies not necessarily associated with acid-base dysfunction such as cancer, glaucoma, or various neurological diseases. The membranous location of the SLC4 transporters as well as recent advances in discovering their structural biology makes them accessible and attractive as a druggable target in a disease context. The role of sodium-coupled bicarbonate transporters in such a large array of conditions illustrates the potential of treating a wide range of disease states by modifying function of these transporters, whether that be through inhibition or enhancement.

[Quality control of red blood cell pockets produced at Centre National de Transfusion Sanguine de Lomé]. / Evaluation de la qualité des concentrés de globules rouges produits au Centre National de Transfusion Sanguine de Lomé.

INTRODUCTION: at the National Center for Blood Transfusion (NCBT) in Lomé, whole blood is systematically separated into its various labile blood products. This study aims to assess the quality of the red blood cell concentrates (RBCC) produced. METHODS: we conducted a cross-sectional study on 260 RBCCs (204 adult units and 56 paediatric units) from January to March 2018. The bags were weighed to determine the volume of their content. Hemoglobin and hematocrit levels were determined using the Horiba Medical Pentra XLR device. We evaluated the fidelity and precision of the device in order to ensure the accuracy of the measurements of the variables analyzed. Statistical analyses were performed using the R software. RESULTS: adult units assessment showed that 79.90%; 81.86% and 43.13% bags were consistent with respect to the volume and haemoglobin and haematocrit levels. Paediatric units assessment showed that 98.21%; 69.64% and 37.50% bags were consistent with respect to the volume and haemoglobin and haematocrit levels. Simultaneous analysis of the three parameters showed a compliance rate of 42.16% for RBCCs in adults against 35.71% for pediatric RBCCs. CONCLUSION: we recommend to expand the interval between two blood donations and to perform hemoglobin test before blood donation in compliance with the eligibility criteria for giving blood at the National Center for Blood Transfusion in Lomé.

Intracellular pH regulation by acid-base transporters in mammalian neurons.

Intracellular pH (pHi) regulation in the brain is important in both physiological and physiopathological conditions because changes in pHi generally result in altered neuronal excitability. In this review, we will cover 4 major areas: (1) The effect of pHi on cellular processes in the brain, including channel activity and neuronal excitability. (2) pHi homeostasis and how it is determined by the balance between rates of acid loading (J L) and extrusion (J E). The balance between J E and J L determine steady-state pHi, as well as the ability of the cell to defend pHi in the face of extracellular acid-base disturbances (e.g., metabolic acidosis). (3) The properties and importance of members of the SLC4 and SLC9 families of acid-base transporters expressed in the brain that contribute to J L (namely the Cl-HCO3 exchanger AE3) and J E (the Na-H exchangers NHE1, NHE3, and NHE5 as well as the Na(+)- coupled HCO3 (-) transporters NBCe1, NBCn1, NDCBE, and NBCn2). (4) The effect of acid-base disturbances on neuronal function and the roles of acid-base transporters in defending neuronal pHi under physiopathologic conditions.