Reduced cerebrospinal fluid BACE1 activity in multiple sclerosis.

BACKGROUND: Cell and animal experiments have shown that beta-site APP-cleaving enzyme 1 (BACE1) may be involved in myelination. OBJECTIVE: Here, we assess the association of cerebrospinal fluid (CSF) BACE1 activity with multiple sclerosis (MS). METHODS: BACE1 activity and levels of secreted amyloid precursor protein (APP) and amyloid-beta (Abeta) isoforms were analyzed in CSF from 100 patients with MS and 114 neurologically healthy controls. Patients with systemic lupus erythematosus (SLE), 26 with and 41 without cerebral engagement, were also included to enable comparisons with regards to another autoimmune disease. A subset of patients with MS and controls underwent a second lumbar puncture after 10 years. RESULTS: MS patients had lower CSF BACE1 activity than controls (P = 0.03) and patients with cerebral SLE (P < 0.001). Patients with cerebral SLE had higher BACE1 activity than any other group (P < 0.05 for all comparisons). BACE1 activity correlated with the different amyloid markers in all study groups. BACE1 activity decreased over 10 years in the MS group (P = 0.039) and correlated weakly with clinical disease severity scores in an inverse manner. CONCLUSIONS: These results suggest an involvement of BACE1 in the MS disease process.

Non-neurological surgery results in a neurochemical stress response.

There is a paucity of studies assessing changes in measures of human neurotransmission during stressful events, such as surgery. Thirty-five patients without any neurological disorders undergoing knee replacements with spinal bupivacaine anaesthesia and propofol sedation had cerebrospinal fluid (CSF) drawn from a spinal catheter before, three hours after and the morning after surgery. The CSF concentrations of the dopamine metabolite homovanillinic acid (HVA) and the serotonin metabolite 5-hydroxyindoleacetic acid (5-HIAA), which are related to the activity of the dopaminergic and serotonergic systems of the brain, increased sharply during surgery and reached 188% and 166% of their initial concentrations on the morning after the intervention (p < 0.0001). The CSF concentrations of the norepinephrine metabolite 3-methoxy-4-hydroxyphenylglucol (MHPG) increased modestly (non-significantly) during and after surgery. The HVA/5-HIAA ratios initially increased but returned to the initial level during the night after surgery. We conclude that non-neurological surgery, in this case to the lower limb, is accompanied by a marked central nervous stress response in spite of a spinal blockade.

Cerebrospinal fluid protein reactions during non-neurological surgery.

OBJECTIVE: To study changes in cerebrospinal fluid (CSF) protein markers of blood-CSF barrier integrity and immunological reactions during surgical stress. SUBJECTS AND METHODS: Thirty-five patients without neurological or psychiatric disorders undergoing knee replacements had CSF and serum samples drawn from spinal and arterial catheters before, 3 h after and the morning after surgery. RESULTS: Serum albumin decreased during surgery and CSF albumin decreased during and after surgery, and, as a consequence, the CSF/serum albumin ratio decreased significantly during the study period, especially after the intervention. In contrast, CSF concentrations of beta-2-microglobuline (beta2M) increased significantly during surgery and remained high. The CSF general marker beta-trace protein (betaTP) remained unchanged. CONCLUSIONS: Central nervous system protein reactions to a non-neurological surgical intervention include sharply decreased permeability of albumin into the CSF and signs of intrathecal inflammatory activity.