Human RBP4 blocking peptide

Objective: To identify differentially expressed serum proteins that could serve as sensitive biomarkers of heterotopic ossification in patients with traumatic brain injury. Methods: From August 2014 to December 2015, 18 patients with traumatic brain injury were enrolled in the study, and blood samples were collected. Patients with traumatic brain injury were divided based on the presence (n = 9 patients, heterotopic ossification group) or absence (n =9 patients, traumatic brain injury group or control group) of heterotopic ossification. Protein expression profiles were compared using 2-dimensional electrophoresis. Differentially expressed proteins were examined using matrix-assisted laser desorption/ionization and time-of-flight tandem mass spectrometry (MALDI-TOF/TOF). The differentially expressed proteins identified were further confirmed by Western blotting. Results: Seven protein spots were differentially expressed between heterotopic ossification and traumatic brain injury groups in 2-dimensional electrophoresis analysis. Vitamin D binding protein (Gc protein), retinol binding protein 4 (RBP4) and haptoglobin expression decreased significantly in the heterotopic ossification group compared with the control group (p < 0.05), and this was further confirmed by Western blotting. Conclusion: Lower levels of expression of Gc protein, RBP4 and haptoglobin may be closely related to heterotopic ossification after traumatic brain injury. These proteins may be potential biomarkers of heterotopic ossification secondary to traumatic brain injury.

The aim was to investigate the relationship between retinol-binding protein 4 (RBP4) levels and short-term functional outcome, and to determine its possible role in acute ischemic stroke (AIS). In a prospective observational study, 299 first-ever AIS who were admitted to our hospital were included. Serum levels of RBP4 were assayed and severity of stroke was evaluated with the National Institutes of Health Stroke Scale (NIHSS) score on admission. The prognostic value of RBP4 to predict the poor outcome within 3 months was compared with the NIHSS and with other known outcome predictors. The median age of the included patients was 66 (interquartile range (IQR): 55-77) years and 155 (51.8%) were women. A poor functional outcome was found in 88 patients (29.4%), and significantly higher RBP4 values were found in poor outcomes rather than good outcomes patients (P < 0.001). The poor outcomes distribution across the RBP4 quartiles ranged between 9.3% (first quartile) and 60.8% (fourth quartile). In multivariate models comparing the second(Q2), third, and fourth quartiles against the first quartile of the RBP4, RBP4 in Q3 and Q4 were associated with poor functional outcome, and increased risk of poor functional outcome by 144% (OR: 2.44; 95% confidence interval (CI): 1.22-5.03) and 602% (7.02; 3.11-12.24), respectively. Interestingly, RBP4 improved the NIHSS score (area under the curve (AUC) of the combined model, 0.79; 95% CI: 0.74-0.85; P < 0.001). The data showed that elevated serum levels of RBP4 at admission were associated with severity and prognosis of AIS, suggesting that vitamin A metabolism or impaired insulin signaling could be involved.