Cerebrospinal Fluid Stanniocalcin-1 as a Biomarker for Alzheimer's Disease and Other Neurodegenerative Disorders.

Stanniocalcin-1 (STC-1) is a nerve cell-enriched protein involved in intracellular calcium homeostasis regulation. Changes in calcium regulation are hypothesized to play a role in the pathophysiology of Alzheimer's disease (AD). The expression of STC-1 increases in response to ischemic stroke, but whether it is altered in neurodegenerative disorder, particularly Alzheimer's disease (AD), has not been investigated before. We measured STC-1 in cerebrospinal fluid (CSF) samples from a total of 163 individuals including AD, prodromal AD (pAD), mixed AD, stable mild cognitive impairment (sMCI), and diagnoses of other dementia than AD, as well as cognitively normal controls (CNC) enrolled at academic centers in France and Sweden. STC-1 concentration was reliably measureable in all CSF samples and was significantly increased in the initial exploratory cohort of neurochemically enriched AD patients versus AD biomarker-negative controls. In the second cohort, STC-1 was increased in AD versus pAD, and other dementia disorders, but the difference was not statistically significant. In the third cohort, there was no significant difference in STC-1 concentration between AD and CNC; however, STC-1 concentration was significantly decreased in patients with other dementia disorders compared with AD and CNC. Taken together, CSF STC-1 showed an increasing trend in AD, but the findings were not consistent across the three study cohorts. In contrast, CSF STC-1 concentrations were reduced in patients with dementia diagnoses other than AD, as compared with both AD patients and CNC. The findings from these studies suggest CSF STC-1 as a potential biomarker in differential diagnosis of dementias.