Lectin complement pathway initiators after subarachnoid hemorrhage - an observational study

Abstract

Background: This exploratory study investigated the time-course of lectin complement pathway (LCP) initiators in cerebrospinal fluid (CSF) and plasma in patients with subarachnoid hemorrhage (SAH), as well as their relationship to delayed cerebral ischemia (DCI) and functional outcome.

Methods: Concentrations of ficolin-1, ficolin-2, ficolin-3, and mannose-binding lectin (MBL) were analyzed in CSF and plasma from patients with SAH. Samples were collected daily from admission until day 9 (CSF; N_PATIENTS = 63, n_SAMPLES = 399) and day 8 (plasma; N_PATIENTS = 50, n_SAMPLES = 358), respectively. Twelve neurologically healthy patients undergoing spinal anesthesia and 12 healthy blood donors served as controls. The development of DCI during hospitalization and functional outcome at 3 months (modified Rankin Scale) were registered for patients.

Results: On admission, CSF levels of all LCP initiators were increased in SAH patients compared with healthy controls. Levels declined gradually over days in patients; however, a biphasic course was observed for ficolin-1. Increased CSF levels of all LCP initiators were associated with a poor functional outcome in univariate analyses. This relationship persisted for ficolin-1 and MBL in multivariate analysis after adjustments for confounders (age, sex, clinical severity, distribution and amount of blood on CT-imaging) and multiple testing (1.87 ng/mL higher in average, 95% CI, 1.17 to 2.99 and 1.69 ng/mL higher in average, 95% CI, 1.09 to 2.63, respectively). In patients who developed DCI compared with those without DCI, CSF levels of ficolin-1 and MBL tended to increase slightly more over time (p_interaction = 0.021 and 0.033, respectively); however, no association was found after adjustments for confounders and multiple testing (p-adj_interaction = 0.086 and 0.098, respectively). Plasma ficolin-1 and ficolin-3 were lower in SAH patients compared with healthy controls on all days. DCI and functional outcome were not associated with LCP initiator levels in plasma.

Conclusion: Patients with SAH displayed elevated CSF levels of ficolin-1, ficolin-2, ficolin-3, and MBL. Increased CSF levels of ficolin-1 and MBL were associated with a poor functional outcome.

Trial registration: This study was a retrospective analysis of samples, which had been prospectively sampled and stored in a biobank. Registered at clinicaltrials.gov ( NCT01791257 , February 13, 2013, and NCT02320539 , December 19, 2014).

Keywords: Delayed cerebral ischemia; Ficolin; Functional outcome; Lectin complement pathway; Subarachnoid hemorrhage.

Conflict of interest statement

The authors declare that they have no competing interest and no conflict of interest with respect to the research, authorship, and publication.

Figures

Fig. 1

Daily levels of LCP initiators. Daily levels of ficolin-1, ficolin-2, ficolin-3, and MBL in CSF (left) and plasma (right) in patients with SAH (black) and neurologically healthy patients (green). The daily levels are presented as medians in CSF and as means in plasma. Error bars show ±1 SD. Asterisks (*) indicate significance on specific days after SAH compared to control patients (p < 0.05) using Wilcoxon’s rank-sum test. Each LCP initiator graph is based on a total number of 399 CSF samples from 63 SAH patients (mean number of samples per patient, 7; range, 6–8), 358 plasma samples from 50 SAH patients (mean number of samples per patient, 7; range, 6–8), and 12 control samples from 12 neurologically healthy patients. MBL: Mannose-binding lectin, CSF: Cerebrospinal fluid, SAH: Subarachnoid hemorrhage

Fig. 2

Predicted daily LCP initiator levels in SAH patients with or without the development of DCI. Predicted daily levels of ficolin-1, ficolin-2, ficolin-3, and MBL in CSF (left) and in plasma (right) in patients with (blue) or without (red) the development of DCI. The predicted daily levels are presented as medians in CSF and as means in plasma. Error bars show 95% confidence intervals. P values shown in the bottom left of each graph are adjusted for confounders (age, sex, WFNS, and Fisher score) and multiple testing (Benjamini-Hochberg procedure) and represent the overall difference in concentration between groups (p-adj) and overall different development over time (p-adj_interaction) for each LCP initiator. Asterisks indicate (*) significant levels on specific days <0.05. Each LCP initiator graph is based on a total number of 241 CSF samples from 36 SAH patients (mean number of samples per patient, 7; range, 6–8) and 233 plasma samples from 33 SAH patients (mean number of samples per patient, 7; range, 6–8). LCP: Lectin complement pathway, MBL: Mannose-binding lectin, CSF: Cerebrospinal fluid, CT: Computed tomography, DCI: Delayed cerebral ischemia, SAH: Subarachnoid hemorrhage

Fig. 3

Predicted daily levels of LCP initiators in SAH patients with poor versus good functional outcome. Predicted daily levels of ficolin-1, ficolin-2, ficolin-3, and MBL in CSF (left) and in plasma (right) in patients with a poor (blue) and good (red) functional outcome. The predicted daily levels are presented as medians in CSF and as means in plasma. Error bars show 95% confidence intervals. P values shown in the bottom left of each graph are adjusted for confounders (age, sex, WFNS, and Fisher score) and multiple testing (Benjamini-Hochberg procedure) and represent the overall difference in concentration between groups (p-adj) and overall different development over time (p-adj_interaction) for each LCP initiator. Asterisks (*) indicate significant levels on specific days <0.05. Each LCP initiator graph is based on a total number of 399 CSF samples from 63 SAH patients (mean number of samples per patient, 7; range, 6–8) and 358 plasma samples from 50 SAH patients (mean number of samples per patient, 7; range, 6–8). MBL: Mannan-binding lectin, CSF: Cerebrospinal fluid, SAH = subarachnoid hemorrhage