Modeling Cerebrospinal Fluid Flow and Transport with Physiologically-Based Cilia Orientation and Dysfunction

Cerebrospinal fluid (CSF) within the brain ventricles serves a biological function of nutrient delivery and waste removal, driven by ependymal cilia. Unlike in idealized models of uniform carpets, cilia within the ventricular walls exhibit clustering and non-uniform orientation; furthermore, ciliopathies can produce missing or dysfunctional cilia. We developed a computational CSF flow model that incorporates physiologically measured distributions of ependymal cell polarity and cilia dynamics within the spectral element solver Nek5000.

We simulate three health states: healthy (0\% missing cilia), mildly unhealthy (16.7\% missing), and strongly unhealthy (33.3\% missing) across three random polarity realizations, each run for twenty beat cycles. We quantify the differences in the near‑wall velocity, volumetric flow rate, wall pressure, and wall shear stress, between healthy and unhealthy cases.

Results reveal a decline in pumping efficiency with a ciliary loss, accompanied by proportional decreases in the wall pressure and the wall shear stress. These findings shed some light on how the integrity of the ependymal cilia maintains CSF-mediated homeostasis and suggest mechanistic links between ciliopathies and neurological disorders such as hydrocephalus and Alzheimer’s disease.