A-FABP linked to stroke risk, fatality
MedWire News: Levels of adipocyte fatty acid-binding protein (A-FABP) are elevated in patients with stroke, especially among those at high risk for early mortality, shows a case-control study.
"These findings raise the possibility that serum A-FABP may be a potential biomarker to detect individuals at risk of ischemic stroke or at risk of early mortality on presentation of acute stroke," Karen Lam (University of Hong Kong) and colleagues write in the journal Neurology.
But editorialists Michael Skilton (University of Sydney, Australia) and Gail Pyne-Geithman (University of Cincinnati, Ohio, USA) stressed that case-control designs cannot determine causality. "Which came first?" they asked. "Elevated A-FABP or a predisposing metabolic perturbation?"
Lam and team measured A-FABP levels in 306 stroke patients, within 48 hours of hospital admission, and in 306 controls who were free of vascular disease and were matched for age, gender, and body mass index (BMI).
They report that cases had significantly higher average A-FABP levels than controls, at 19.6 versus 15.2 ng/ml among men and 32.4 versus 22.0 ng/ml among women.
The increased A-FABP level was not merely an effect of acute stroke; levels were also elevated in a group of 116 stroke survivors (at least 6 months after onset), at 22.5 ng/ml in men and 33.5 ng/ml in women.
A-FABP remained associated with both acute and chronic stroke, after accounting for confounders including hypertension, diabetes, dyslipidemia, and smoking.
However, the highest A-FABP levels were found among an additional group of 60 stroke patients who died within 3 months of onset, at 38.0 ng/ml among men and 54.0 ng/ml among women.
A-FABP levels were positively associated with National Institutes of Health Stroke Scale scores among all acute stroke patients. Both of these variables were independently associated with early mortality risk, as was older age.
In their editorial, Skilton and Pyne-Geithman also questioned whether the effect of A-FABP is truly independent from that of obesity. Although cases and controls were matched for BMI, the editorialists noted that it is "a relatively crude measure of adiposity, failing to capture region- and site-specific adiposity that are important patho-physiologic contributors to atherosclerosis-related clinical events."
They added: "Given the reported correlation of A-FABP as a risk factor in multiple related pathologic states, it is unlikely that A-FABP will be adopted as a biomarker for ischemic stroke specifically.
"However, a deeper understanding of the relationship between A-FABP and these pathologic states is likely to be of importance in the targeted development of therapeutic targets, disease progression monitoring, and treatment efficacy monitoring."
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By Eleanor McDermid