A prospective cohort study on decreased serum apelin-13 levels after human aneurysmal subarachnoid hemorrhage: associations with severity and prognosis.

Apelin-13 may have neuroprotective effects. We aimed to determine whether serum apelin-13 could serve as a potential biomarker for severity, delayed cerebral ischemia (DCI), and prognosis after human aneurysmal subarachnoid hemorrhage (aSAH). In this prospective, observational, cohort, single-center study of 139 patients with aSAH and 139 healthy individuals, serum apelin-13 levels were determined. The indicators of stroke severity were the Hunt-Hess scale and the modified Fisher grading scale. The prognostic parameters were DCI and 6-month worse prognosis (Extended Glasgow Outcome Scale scores of 1-4). Using binary logistic regression analysis, the relationship between serum apelin-13 levels and prognosis was reported as odds ratios (ORs) with 95% confidence intervals (CIs). Under the receiver operating characteristic curve, prognostic abilities were shown as areas under the curve (AUCs) with 95% CIs. Serum apelin-13 levels were substantially lower in patients than in controls (median, 28.8 versus 48.6 ng/ml; P < 0.001), in patients with DCI than in non-DCI patients (median, 14.9 versus 31.6 ng/ml; P < 0.001), and in patients with worse prognosis than in those with good prognosis (median, 16.3 versus 33.7 ng/ml; P < 0.001). Serum apelin-13 levels were independently correlated with Hunt-Hess scores (beta, -6.836; 95% CI, -8.963-4.708; VIF, 2.219; P = 0.001) and modified Fisher scores (beta, -3.350; 95% CI, -6.151-0.549; VIF, 1.562; P = 0.019). Serum apelin-13 levels were an independent predictor of DCI (OR, 0.951; 95% CI, 0.914-0.990; P = 0.022) and worse prognosis (OR, 0.954; 95% CI, 0.916-0.993; P = 0.013). Serum apelin-13 levels significantly differentiated DCI and poor prognosis, with AUCs of 0.753 (95% CI, 0.656-0.850) and 0.791 (95% CI, 0.713-0.868) respectively. Using the Youden method, serum apelin-13 levels < 19.3 ng/ml distinguished the risk of DCI with 64.7% sensitivity and 77.1% specificity, and serum apelin-13 levels < 30.2 ng/ml discriminated the development of worse prognosis with 89.1% sensitivity and 63.4% specificity. Serum apelin-13 levels combined with Hunt-Hess scores and modified Fisher scores displayed a significantly higher AUC than any one of them for prognostic prediction (all P < 0.05). Decreased serum apelin-13 levels, which are strongly correlated with disease severity, independently predicted poor outcomes following aSAH, substantializing serum apelin-13 as a useful prognostic biomarker of aSAH.

Variable stiffness performance analysis of layer jamming actuator based on bionic adhesive flaps.

Soft actuators made of soft materials cannot generate precisely efficient output forces compared to rigid actuators. It is a promising strategy to equip soft actuators with variable stiffness modules of layer jamming mechanism, which could increase their stiffness as needed. Inspired by the gecko's the array of setae, bionic adhesive flaps with inclined micropillars are applied in layer jamming mechanism. In this paper, after the manufacturing process of the layer jamming actuator based on the bionic adhesive flaps is described, the equivalent stiffness models of the whole actuator are established in the unjammed and jammed states. And the shear adhesive force of a single micropillar is calculated based on the Kendall viscoelastic band model. The finite element simulation results of two bionic adhesive flaps show that the interlaminar shear stress and stiffness increase with the increase of pressure. The measurement of shear adhesive force show that the critical shear adhesive force of the bionic adhesive material is 3.2 times that of polyethylene terephthalate (PET) material, and exhibit the ability of anisotropic adhesion behavior. The variable stiffness performance of the layer jamming actuator based on bionic adhesive flaps is evaluated by three test methods, and the max stiffness reaches 8.027 N mm-1, which is 1.5 times higher than the stiffness of the layer jamming actuator based on the PET flaps. All results of simulation and experiment effectively verify the validity and superiority of applying the bionic adhesive flaps to the layer jamming mechanism to enhance the stiffness.

Utility of serum macrophage migration inhibitory factor as a potential biomarker for detection of cerebrocardiac syndrome following severe traumatic brain injury.

BACKGROUND: Cerebrocardiac syndrome (CCS) is a common complication after severe traumatic brain injury (sTBI) and its occurrence obviously increases the risk of a poor outcome. Macrophage migration inhibitory factor (MIF) acts as an inflammatory cytokine and its circulating concentration are related to acute heart and brain injury. The aim of this study was to examine the association of serum concentration of MIF with posttraumatic CCS. METHODS: From January 2016 to February 2019, 116 sTBI patients and 116 healthy controls with similar age and gender percentage were recruited. Relationship between serum MIF concentration and CCS was assessed using multivariate analysis. RESULTS: Serum MIF concentration of patients were significantly higher than those among controls. Serum MIF concentration were intimately correlated with Glasgow coma scale scores (t = -5.553, P < 0.001) and serum C-reactive protein concentration (t = 5.320, P < 0.001) in a multivariate linear regression model. 61 patients (52.6%) displayed CCS. Under ROC curve analylsis, there was a strong discriminatory ability for CCS regarding serum MIF concentration (area under curve, 0.834; 95% confidence interval, 0.754-0.897). Serum MIF concentration were highly associated with CCS independent of other confounding factors (odds ratio, 5.608; 95% CI: 1.896-16.587). CONCLUSIONS: Increased MIF in serum may be a useful biomarker for early detection of CCS after head trauma.