Increased levels of soluble triggering receptor expressed on myeloid cells-1 in cerebrospinal fluid of subarachnoid hemorrhage patients

Triggering receptor expressed on myeloid cells-1 (TREM-1) has been highlighted as a key amplifier of inflammatory response in various diseases. To determine the contribution of TREM-1 in the inflammatory cascade after subarachnoid hemorrhage (SAH), concentrations of soluble TREM-1 (sTREM-1) in cerebrospinal fluid (CSF) from 30 SAH patients and 9 healthy volunteers were measured by enzyme-linked immunosorbent assay. It was shown that the CSF sTREM-1 levels of SAH patients increased significantly than that of the volunteers (P < 0.05). Interestingly, the levels were up-regulated dynamically over time with an early increase within 2 days and a late peak at day 6 after SAH onset. In addition, it was found that the early sTREM-1 levels (within 3 days post-SAH) were negatively correlated with Glasgow Coma Scale (r = −0.550, P = 0.022) and positively correlated with the Hunt and Hess scale (r = 0.603, P = 0.010) respectively conducted on admission, also the early sTREM-1 levels were negatively correlated with Glasgow Outcome Scale (r = −0.505, P = 0.039) and positively correlated with modified Rankin Scale (r = 0.557, P = 0.020) respectively conducted one month after SAH. Altogether, this is the first study showing CSF sTREM-1 dynamics in SAH patients, and exploring the correlations of early CSF sTREM-1 levels to patients’ severity and prognosis, which suggests that TREM-1 may play an important role in the inflammatory cascade after SAH and act as a monitoring biomarker facilitated to assess the severity and prognosis of SAH patients.