Deformabilidade eritrocitária na anemia ferropriva

Abstract

A deformabilidade é a característica que permite ao eritrócito normal de 7 a 8 micrômetros (µm) circular por capilares de até 3 µm de diâmetro. Esse fenômeno depende da geometria celular, da viscosidade interna e de propriedades visco-elásticas da membrana eritrocitária. Dentre as técnicas de estudo da deformabilidade eritrocitária (DE), como aspiração por micropipeta, filtração e reoscopia, destaca-se a ectacitometria. Esta técnica utiliza um viscosímetro de fluxo laminar no qual as modificações de forma dos eritrócitos são monitoradas continuamente por um feixe de raio laser, processadas por microcomputador, gerando o "Índice de Deformabilidade" (ID), que mede a eliptocitogênese dos eritrócitos quando submetidos a uma força denominada "shear stress". Alterações de DE foram descritas em diversas situações, como em anemias hemolíticas hereditárias ou auto-imunes. Na anemia ferropriva, os trabalhos são controversos. O presente estudo avalia a DE em 21 pacientes portadores de anemia ferropriva, utilizando a ectacitometria. Os resultados obtidos a partir do ID demonstram DE diminuída nesses doentes, quando comparada ao grupo controle (p< 0,0007). O presente estudo sugere que o fator responsável pela diminuição da DE na anemia ferropriva é a microcitose. Recentemente, relatos desta anemia associada a fenômenos trombóticos aumentaram o interesse no estudo da DE para melhor entendimento desses casos.

The pequi pulp oil (Caryocar brasiliense Camb.) provides protection against aging-related anemia, inflammation and oxidative stress in Swiss mice, especially in females

“…Some authors suggest that in iron deficiency anemia there is a reduction in the survival of the microcytic and hypochromic RBCs, and that one of the main factors would be their reduced flexibility. This fact would be related to the lower internal hemoglobin content and unfavorable surface/volume ratio of the cell, with consequent early sequestration by the reticuloendothelial system ( Patavino et al , 2006 ). As pequi is rich in iron, this could explain the increase in HGB and HCT and, consequently, the lack of significant differences observed for HGB and HCT in female controls of 11-12 months compared to 6-7 months.…”

Impaired red cell deformability in iron deficient subjects

“…Earlier approaches, using rat RBC as a model, demonstrated that this less deformable cell could be a consequence of peroxidation damage to membrane cell lipids or the crosslinking of the membrane proteins [3]. Other authors, using ectacytometry approach, demonstrated a diminished erythrocyte deformability in individuals with iron deficiency anemia [5]. On the other hand, Reinhart [4] using the filter aspiration technique, erythrocyte elongation and membrane elasticity measurement showed that, iron deficient RBCs had a similar deformability to control RBCs.…”

“…The iron deficient Red Blood Cell (idRBC) elasticity status is controversial, as, although many rheological studies suggest that RBC deformability is impaired [2][3][4][5], others, however do not confirm these observations [6,7].…”

An experimental erythrocyte rigidity index (Ri) and its correlations with Transcranial Doppler velocities (TAMMV), Gosling Pulsatility Index PI, hematocrit, hemoglobin concentration and red cell distribution width (RDW)

“…The need to develop low-cost techniques to evaluate red cell rigidity is a present issue for Hematology because the techniques used are restricted to the countries or regions of the world where they appeared. Throughout Brazil, with the sixth world population, we have news of one single piece of equipment [101]. Moreover, new experimental techniques to measure red cell deformability continuously appear, indicating the inexistence of a universalized method.…”