Through extensive modeling carried out on one of the world's fastest supercomputers at the National Institute for Computational Sciences, Karniadakis and colleagues found that malaria-infected red blood cells stiffened as much as 50 times more than healthy red blood cells. The result: Infected red blood cells, having lost their elasticity, could no longer pass through capillaries, effectively blocking them.
"Basically what happens is the brain could be deprived of nutrients and oxygen," said Karniadakis, a member of the Center for Fluid Dynamics, Turbulence and Computation at Brown. "This happens because of the deformation of these red blood cells.
"This shows that as stiffening increases (in red blood cells), the viscosity of the blood increases, and the heart has to pump twice as much sometimes to get the same blood flow," Karniadakis added.
The researchers also found that infected red blood cells had a tendency to stick, flip, and flop along the walls of blood vessels — unlike healthy blood cells that flow in the middle of the channel. For reasons not entirely known, the infected red blood cells develop little knobby protrusions on their cellular skin that tend to stick to the surface of the blood wall, known as the endothelium. Scientists call the sticking cytoadhesion.
"So, what happens is the infected red blood cell is not only stiffer, it's slowed down by this interaction (cytoadhesion)," Karniadakis said. "This drastically changes the flow of blood in the brain, especially in the arterials and in the capillaries."
Malaria-infected red blood cells can be 50 times stiffer and have surface changes that disrupt the smooth flow of blood, depriving the brain and other organs of nutrients and oxygen.
(Photo Credit: George Karniadakis laboratory, Brown University)
The malaria parasite inside a red blood cell, left, and in a computer-generated model. Malarial infection inhibits the smooth flow of blood through capillaries.
(Photo Credit: George Karniadakis, Brown University)
Source: Brown University