Authors: Martha Powell, Future Science Group
Researchers at University of British Columbia (Vancouver, Canada) have developed a method to quickly and sensitively assess the progression of malaria via the deformability of red blood cells associated with haemolytic anemia.
It has previously been hypothesized that extracellular heme – the non-protein component of hemoglobin – may play a crucial role in malaria pathogenesis. The parasite can cause toxic levels of heme inducing oxidative stress in red blood cells (RBCs) and consequently rigidification, destruction and removal from the blood – together consituting hemolytic anemia.
The study, published recently in Integrative Biology, reports that the concentration of oxidized heme in the blood is directly correlated with the rigidity of RBCs. As heme is challenging to measure directly, monitoring changes in RBC deformability may therefore serve as a marker of heme, and therefore malaria progression.
Lead author, Kerryn Matthews (University of British Columbia), explained: “Because this method is mechanical, it’s well suited for use in resource-poor countries, where the vast majority of malaria transmission takes place. Other methods of analyzing malaria severity require training or expensive equipment or chemicals that are not readily available in developing nations.”
The new method uses a microfluidic device with 34 parallel funnel-shaped channels, termed the ‘multiplex fluidic plunger’; carefully controlled pressures can be simultaneously applied across these channels. The plunger can be loaded with whole blood and RBCs dock at each channel, where increasing pressure can be applied until the cell is squeezed through, giving a measurement of rigidity. This method allowed the team to determine cortical tensions of many cells and build a deformability profile for the patient.
Matthews commented: “The device can be easily integrated with a conventional microscope coupled with a digital camera and the accompanying software, which does all the analysis and records the pressures, is simple to use.”
This device is potentially a sensitive method for measuring heme-related oxidative stress and could be used to clinically assess disease progression in malaria. In addition, the researchers suggest it may not only be useful for detection, but could also be used in the development of antimalarials.
Sources: Matthews K, Duffy SP, Myrand-Lapierre M, Ang RR, Scott MD & Ma H. Microfluidic analysis of red blood cell deformability as a means to assess hemin-induced oxidative stress resulting from Plasmodium falciparum intraerythrocytic parasitism. Integ. Biol. 9, 519–528 (2017); https://apsc.ubc.ca/spotlight/research/new-malaria-analysis-method-reveals-disease-severity-minutes