Gelsolin is a highly conserved intracellular actin-binding protein with an extracellular isoform, plasma gelsolin, for which there is not yet a clearly defined function.Materials and methods
In this study, we determined gelsolin concentrations in blood and cerebrospinal fluid (CSF) obtained from 25 subjects using immunoblotting and a functional assay that quantifies gelsolin's ability to accelerate actin polymerization.Results
The gelsolin concentration in CSF, determined by quantitative immunoblotting was 1.2–15.9 μg/ml (average 5.9 ± 3.8 μg/ml). In samples obtained from patients diagnosed with conditions that do not alter standard CSF clinical tests [(idiopathic cephalgia, ischialgia due to discopathy, and idiopathic (Bell's) facial nerve palsy or entrapment radial neuropathy)], the average gelsolin concentration was 7.2 ± 4.3 μg/ml. In contrast, the gelsolin concentration in samples obtained from patients diagnosed with multiple sclerosis was 2.1 ± 0.7 μg/ml, and a similar low concentration was found in a patient recovering from a subarachnoid hemorrhage. The range of CSF gelsolin concentrations determined by the actin polymerization assay was 0.61–9.97 μg/ml (average 3.6 ± 2.2 μg/ml). These lower values compared with those obtained from immunoblotting analysis suggest that CSF gelsolin may bind other CSF molecules leading to a reduction of its actin-binding activity.Conclusions
The results presented here show that CSF gelsolin concentration is significantly altered in certain neurological conditions, including multiple sclerosis, indicating the possible utility of CSF gelsolin levels for diagnostic purposes.