Exercise-induced changes of cerebrospinal fluid vascular endothelial growth factor in adult chronic hydrocephalus patients

Vascular endothelial growth factor (VEGF) is a growth factor demonstrated to be a key factor in cerebral angiogenesis and neurogenesis. It has been considered a critical component in hippocampus neurogenesis and memory formation and has been observed to increase in the rat hippocampus after exercise. We previously found increased VEGF levels in experimental chronic hydrocephalus in several brain areas and cerebrospinal fluid (CSF), suggesting a role in the adaption to chronic hypoxia. Here we investigate the ability of moderate exercise to increase CSF-VEGF levels in adult chronic hydrocephalus patients. Lumbar CSF samples were collected from 17 normal pressure hydrocephalus patients. During CSF collection, 11 patients (exercise group) underwent a standard in-room occupational therapy session; six patients (no-exercise group) did not undergo a physical therapy session. CSF-VEGF levels were evaluated for increase related to exercise and the clinical response to CSF drainage. CSF-VEGF levels in the exercise group demonstrated significant increases 1-3 hours post-exercise compared with the levels 1-2 hours pre-exercise (p=0.04), and also showed significantly higher levels than the no-exercise groups (p=0.03). The post-exercise CSF-VEGF level in the group that did not clinically improve was significantly higher than both their own pre-exercise level (p=0.02) and that seen in the clinically improving group (p=0.05) after exercise. We conclude that CSF-VEGF levels can increase after moderate exercise even in elderly hydrocephalus patients. This suggests that a potential benefit of exercise, especially in CSF drainage non-improved patients, may exist via a central VEGF mechanism.

Biocompatibility evaluation of a thermoplastic rubber for wireless telemetric intracranial pressure sensor coating

This study investigated the biocompatibility of the experimental thermoplastic rubber Arbomatrix(™) that will be used as the protective coating on a novel intracranial pressure (ICP) sensor silicon chip. Arbomatrix(™) was benchmarked against biocompatible commercial silicone rubber shunt tubing in the brain via a rat model with 60-day implant duration. A bare silicon chip was also implanted. The results showed similar cellular distribution in the brain-implant boundary and surrounding tissues. Quantitative analysis of neuron and glia density did not show significant difference between implants. Through histological and immunohistochemical evaluation we conclude that Arbomatrix(™) is well tolerated by the brain. Due to its exceptional barrier properties Arbomatrix(™) has already been shown to be an excellent protective coating for new ICP monitoring chip.