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Delirium is a marker of brain vulnerability, associated with increasing age, pre-existing cognitive impairment and, recently, cerebrospinal fluid (CSF) biomarkers of Alzheimer's disease. This nested case-control study used a targeted quantitative metabolomic methodology to profile the preoperative CSF of patients (n = 54) who developed delirium following arthroplasty (n = 28) and those who did not (n = 26). The aim was to identify novel preoperative markers of delirium, and to assess potential correlations with clinical data. Participants without a diagnosis of dementia (≥65 years) undergoing elective primary hip or knee arthroplasty were postoperatively assessed for delirium once-daily for three days. Groups were compared using multivariate, univariate and receiving operator characteristic (ROC) methods. Multivariate modelling using Orthogonal Partial Least Squares-Discriminant Analysis (OPLS-DA) of metabolomic data readily distinguished between delirium and control groups (R2 ≤ 0.56; Q2 ≤ 0.10). Three metabolites (spermidine, putrescine and glutamine) significantly differed between groups (P < 0.05; FDR < 0.07), and performed well as CSF biomarkers (ROC > 0.75). The biomarker performance of the two polyamines (spermidine/putrescine) was enhanced by ratio with CSF Aβ42 (ROC > 0.8), and spermidine significantly correlated with Aβ42 (pearson r = -0.32; P = 0.018). These findings suggest that spermidine and putrescine levels could be useful markers of postoperative delirium risk, particularly when combined with Aβ42, and this requires further investigation.

The olfactory-type signaling machinery has been known to be involved not only in odorant detection but also in other tissues with unsuspected sensory roles. As a barrier, the choroid plexus (CP) is an active participant in the monitoring of the cerebrospinal fluid (CSF), promptly responding to alterations in its composition. We hypothesized that olfactory signaling could be active in CP, contributing to the surveillance of the CSF composition. We determined the mRNA and protein expression of the major components of the olfactory transduction pathway in the rat CP, including odorant receptors, the olfactory G-protein (Gαolf), adenylate cyclase 3 and cyclic nucleotide-gated channel 2. The functionality of the transduction pathway and the intracellular mechanisms involved were analyzed by DC field potential recording electrophysiological analysis, in an ex vivo CP-brain setup, using polyamines as stimuli and blockers of the downstream signaling pathways. Concentration-dependent responses were obtained for the polyamines studied (cadaverine, putrescine, spermine and spermidine), all known to be present in the CSF. Transfection of a CP epithelial cell line with siRNA against Gαolf effectively knocked down protein expression and reduced the CP cells' response to spermine. Thus, the key components of the olfactory chemosensory apparatus are present and are functional in murine CP, and polyamines seem to trigger both the cAMP and the phospholipase C-inositol 1,4,5-trisphosphate pathways. Olfactory-like chemosensory signaling may be an essential component of the CP chemical surveillance apparatus to detect alterations in the CSF composition, and to elicit responses to modulate and maintain brain homeostasis., (© 2016 Federation of European Biochemical Societies.)

Alpha-difluoromethylornithine (DFMO) was used to reduce 125I-induced brain injury in normal beagle dogs. Different DFMO doses and administration schedules were used to determine if the reduction in brain injury was dependent on dose and/or dependent upon when the drug was administered relative to the radiation treatment. Doses of DFMO of 75 mg/kg/day and 37.5 mg/kg/day given 2 days before, during and for 14 days after irradiation reduced levels of putrescine (PU) in the cerebrospinal fluid relative to controls. Volume of edema was significantly reduced by 75 mg/kg/day of DFMO before, during and after irradiation and by the same dose when the drug was started immediately after irradiation. A reduction in edema volume after 37.5 mg/kg/day before, during and after irradiation was very near significance. Ultrafast CT studies performed on dogs that received a DFMO dose of 75 mg/kg/day before, during and after irradiation suggested that the reduced edema volume was associated with reduced vascular permeability. Volume of necrosis and volume of contrast enhancement (breakdown of the blood-brain barrier) were significantly lower than controls only after a DFMO dose of 75 mg/kg/day before, during and after irradiation. These latter data, coupled with the findings relative to edema, suggest that different mechanisms may be involved with respect to the effects of DFMO on brain injury, or that the extents of edema, necrosis and breakdown of the blood-brain barrier may depend upon different levels of polyamine depletion. The precise mechanisms by which DFMO exerts the effects observed here need to be determined.

Cerebrospinal fluid (CSF) polyamines were measured in children with acute lymphocytic leukemia or non-Hodgkin's lymphoma in various stages of the disease ranging from complete remission to active central nervous system (CNS) involvement. Polyamines were analyzed by ion exchange chromatography with o- pthalaldehyde fluorimetric detection. Putrescine concentrations in random CSF samples obtained from leukemic patients with and without CNS involvement were not significantly different. Spermidine levels were generally higher in patients without CNS leukemia than in patients with the disease. In serial CSF specimens from an individual patient, spermidine levels correlated well with clinical status, being high in the active stages of the disease and low in remission. Thus, CSF polyamines appear to be of limited value as a screening test for early detection of CNS leukemia; however, they may offer an additional means of evaluating CNS leukemia and its response to therapy.

Cerebrospinal fluid (CSF) polyamine concentrations were assayed in patients with and without central nervous system tumors, using a high-pressure liquid chromatographic technique. Definite elevations were found in the CFS polyamine concentrations of patients with untreated malignant central nervous system tumors when compared with those concentrations observed in the CSF of patients without neoplasia. Patients undergoing successful tumor therapy for malignant central nervous system tumors showed CSF polyamine concentrations that closely approximated the concentrations found in the CSF of patients without tumor.

Seventy-five cerebrospinal fluid polyamine determinations were evaluated in 16 patients with medulloblastoma. Parameters utilized in evaluating patient status for correlation with the polyamine concentrations were neurological examination, computerized tomography, radionuclide scan, myelography, and cerebrospinal fluid cytology. Fifteen of the 16 patients showed absolute correlation with the eventual clinical picture. One determination on one patient resulted in a false negative. No false positives have been observed to date.