The results of a research collaboration between the neuroscience group of QPS Netherlands B.V. and Professor Peter Paul de Deyn and coworkers of the Department of Neurology and Alzheimer Research Center, University Medical Center Groningen, were recently published in the European Journal of Clinical Investigations (Naudé et al. 2017) entitled “Dynamics of neutrophil gelatinase-associated lipocalin plasma and cerebrospinal fluid concentrations in older males”. The background of this study is that neutrophil gelatinase-associated lipocalin (NGAL), an inflammatory protein, is gaining increasing interest for its use as marker in blood and cerebrospinal fluid (CSF) for several chronic diseases. Its biochemical properties make it an attractive marker. However, changes in blood and CSF NGAL concentrations during the diurnal rhythm in the elderly are unknown. This information is important for determining the optimal use of NAGL as a biomarker in studies with older adults. For this study serial paired plasma and CSF samples were used from 8 healthy, elderly males over a 30-hour period. ELISA was used to quantify NGAL and cortisol. No significant changes in plasma and CSF NGAL concentrations overtime were found, whereas cortisol (included as internal control) concentrations displayed significant changes over time. Significant circadian patterns were found for plasma NGAL and for cortisol in both plasma and CSF. However, CSF NGAL concentrations did not follow a diurnal pattern in elderly males. This study illustrates the temporal regulation of NGAL in plasma and CSF, which potentially is a useful reference for studies measuring NGAL as a biomarker in older individuals.
Diurnal regulation of plasma and cerebrospinal fluid (CSF) of neutrophil gelatinase-associated lipocalin (NGAL) and cortisol illustrated by cosinor fits. Data presented as mean-adjusted average of NGAL and cortisol levels over 30 hours for all subjects. (A) Plasma NGAL; (B) CSF NGAL; (C) Plasma cortisol; (D) CSF cortisol.
CSF sampling at the Clinical Pharmacology Unit at QPS Netherlands B.V.
Izaak den Daas, PhD, clinical pharmacologist, Principal Scientist
Khalid Abd-Elaziz, MD, clinical pharmacologist, Principal Investigator, Associate Medical Director and Safety Officer