Cerebrospinal Fluid Protein Concentrations in Hydrocephalus

Abstract

CSF protein levels are altered in neurological disorders, such as hydrocephalus of different etiologies. In this retrospective observational study, we analyzed cerebrospinal fluid (CSF) samples in hydrocephalic diseases such as aqueductal stenosis (AQS, n = 27), normal pressure hydrocephalus (NPH, n = 24), hydrocephalus communicans (commHC, n = 25) and idiopathic intracranial hypertension (IIH)/pseudotumor cerebri (PC, n = 7) in comparison with neurological patients without hydrocephalic configuration (control, n = 95). CSF was obtained through CSF diversion procedures and lumbar punction and analyzed for protein concentrations according to the institution’s laboratory standards. We found significantly decreased CSF protein levels in patients suffering from AQS (0.13 mg/dL [0.1–0.16 mg/dL] p = 2.28 × 10−8) and from PC (0.18 mg/dL [0.12–0.24 mg/dL] p = 0.01) compared with controls (0.34 mg/dL [0.33–0.35 mg/dL]). Protein levels were not altered in patients suffering from commHC and NPH compared with neurologically healthy individuals. We propose that a decrease in CSF protein levels is part of an active counterregulatory mechanism to lower CSF volume and, subsequently, intracranial pressure in specific diseases. Research regarding said mechanism and more specific proteomic research on a cellular level must still be performed to prove this hypothesis. Differences in protein levels between different diseases point to different etiologies and mechanisms in different hydrocephalic pathologies.

Molecular Signatures of Normal Pressure Hydrocephalus: A Large-scale Proteomic Analysis of Cerebrospinal Fluid

“…Moreover, total CSF protein concentrations measured as part of clinical laboratory testing on LVLP CSF samples of our iNPH participants did not support the dilution effect hypothesis (Mean total CSF protein = 51.2 ± 22.5 mg/dL with normal range of 15-45 mg/dL). Thus, we found no basis for the hypothesis that this might be due to dilution which is also in line with previous studies 39 .…”

Shear thinning behavior of cerebrospinal fluid with elevated protein or cellular concentration

“…For example, flow through CSF shunts implanted to relieve hydrocephalus can be very slow, with shear rates on the order of 1 s -1 . In addition, the presence of the indwelling hardware is known to increase the cellular and protein content of the CSF in these patients [26]. Therefore, the analysis of shunt function would benefit from the consideration of non-Newtonian behavior at low shear rates.…”