The effect of viscous loading on brain ependymal cilia

Abstract

Ependymal cilia line the ventricular system moving cerebral spinal fluid close to the brain surface. They may be exposed to fluid of increasing viscosity in certain pathological conditions such as bacterial meningitis. Our aim was to determine the effect of increasing viscosity on ciliary function.Ciliated ependyma was exposed to solutions of different viscosities (1-60 cP) and ciliary function assessed by highspeed digital imaging.The mean (SD) ciliary beat frequency (CBF), measured after 30 minutes incubation in Medium 199 at 37 o C, was 34.9(2.9) Hz. Increased viscous loading was followed by a rapid decrease in ciliary beat frequency compared to baseline readings (p<0.001). After 15 minutes of exposure to the increased viscous load, CBF reached a new stable level while the viscous load was maintained. Compared to baseline measurements of CBF, viscous loading of 3.7cP caused a 16%, 10.4cP at 34% and 24cP a 70% decrease in beat frequency. Further viscous loading at levels up to 60cP resulted in no further reduction of ependymal CBF. Solutions of 24cP and 40cP had no effect on ciliary amplitude. An increase in viscosity to 60cP caused a significant (30%: p = 0.001) decrease in the ciliary beat amplitude.3

Sensory reception is an attribute of both primary cilia and motile cilia

“…There are emerging hints that a third major population of mammalian motile cilia -ependymal cilia that line the ventricles of the brain -can also respond to changes in viscosity in the extracellular medium (mechanoreception) (O'Callaghan et al, 2008).…”

Mucociliary Clearance Defects in a Murine In Vitro Model of Pneumococcal Airway Infection

“…This can be accomplished by a reduction of the ciliary beat frequency as described in several studies [20], [23], [24]–[29]. However, the biological consequences are largely dependent on the complex hydrodynamic properties of the mucociliary clearance mechanisms [8], [30], [31]. For instance, a 30% reduction of the baseline beat frequency - 12 versus 15 beats per second - is still within the normal range of healthy individuals [32]–[34] and alone might not severely impair mucus flow.…”

The Behaviour of Both Listeria monocytogenes and Rat Ciliated Ependymal Cells Is Altered during Their Co-Culture

“…We recently studied the effect of viscosity on ependymal cells [32] and found an increase in viscous loading was followed by a rapid decrease in the frequency of ependymal cilia to a level that was maintained while the increased viscous load was present. The ciliary beat amplitude was not affected with low viscous loads (1–40 cP) but was reduced at higher viscosities (60 cP).…”