The perivascular pathways for influx of cerebrospinal fluid are most efficient in the midbrain

Although there are no conventional lymphatic vessels in the brain, fluid and solutes drain along basement membranes of cerebral capillaries and arteries towards the subarachnoid space and cervical lymph nodes. Convective influx/glymphatic entry of the cerebrospinal fluid (CSF) into the brain parenchyma occurs along the pial-glial basement membranes of arteries. This project tested the hypotheses that pial-glial basement membranes of arteries are thicker in the midbrain, allowing more glymphatic entry of CSF. The in vivo MRI and PET images were obtained from a 4.2 year old dog, whereas the post-mortem electron microscopy was performed in a 12 year old dog. We demonstrated a significant increase in the thickness of the pial-glial basement membrane in the midbrain compared to the same basement membrane in different regions of the brain and an increase in the convective influx of fluid from the subarachnoid space. These results are highly significant for the intrathecal drug delivery into the brain, indicating that the midbrain is better equipped for convective influx/glymphatic entry of the CSF.
Source: Clinical Science - Category: Biomedical Science Authors: Tags: PublishAheadOfPrint Source Type: research