Biomarkers of acute human spinal cord injury (SCI) could provide a more objective measure of spinal cord damage and a better predictor of neurological outcome than current standardized neurological assessments. In SCI, there is growing interest in establishing biomarkers from cerebrospinal fluid (CSF) and from magnetic resonance imaging (MRI). Here, we compared the ability of CSF and MRI biomarkers to classify injury severity and predict neurological recovery in a cohort of acute cervical SCI patients. CSF samples and MRI scans from 36 acute cervical SCI patients were examined. From the CSF samples taken 24 h post-injury, the concentrations of inflammatory cytokines (interleukin [IL]-6, IL-8, monocyte chemotactic protein-1), and structural proteins (tau, glial fibrillary acidic protein, and S100β) were measured. From the pre-operative MRI scans, we measured intramedullary lesion length, hematoma length, hematoma extent, CSF effacement, cord expansion, and maximal spinal cord compression. Baseline and 6-month post-injury assessments of American Spine Injury Association Impairment Scale (AIS) grade and motor score were conducted. Both MRI measures and CSF biomarker levels were found to correlate with baseline injury grade, and in combination they provided a stronger model for classifying baseline AIS grade than CSF or MRI biomarkers alone. For predicting neurological recovery, the inflammatory CSF biomarkers best predicted AIS grade conversion, whereas structural biomarker levels best predicted motor score improvement. A logistic regression model utilizing CSF biomarkers alone had a 91.2% accuracy at predicting AIS conversion, and was not strengthened by adding MRI features or even knowledge of the baseline AIS grade. In a direct comparison of MRI and CSF biomarkers, the CSF biomarkers discriminate better between different injury severities, and are stronger predictors of neurological recovery in terms of AIS grade and motor score improvement. These findings demonstrate the utility of measuring the acute biological responses to SCI as biomarkers of injury severity and neurological prognosis.

Dermal fibrosis is characterized by a high deposition of extracellular matrix (ECM) and tissue cellularity. Unfortunately all means of treating this condition are unsatisfactory. We have previously reported the anti-fibrotic effects of Kynurenine (Kyn), a tryptophan metabolite, in fibrotic rabbit ear model. Here, we report the mechanism by which Kyn modulates the expression of key ECM components in dermal fibroblasts. The results showed that Kyn activates aryl hydrocarbon receptor (AHR) nuclear translocation and up-regulates cytochrome-P450 (CYP1A-1) expression, the AHR target gene. A specific AHR antagonist, 6,2',4'-trimethoxyflavone, inhibited the Kyn-dependent modulation of CYP1A-1, MMP-1, and type-I collagen expression. Establishing the anti-fibrogenic effect of Kyn and its mechanism of action, we then developed nano-fibrous Kyn slow-releasing dressings and examined their anti-fibrotic efficacy in vitro and in a rat model. Our results showed the feasibility of incorporating Kyn into PVA/PLGA nanofibers, prolonging the Kyn release up to 4 days tested. Application of medicated-dressings significantly improved the dermal fibrosis indicated by MMP-1 induction, alpha-smooth muscle actin and type-I collagen suppression, and reduced tissue cellularity, T-cells and myofibroblasts. This study clarifies the mechanism by which Kyn modulates ECM expression and reports the development of a new slow-releasing anti-fibrogenic dressing. J. Cell. Physiol. 231: 2749-2760, 2016. © 2016 Wiley Periodicals, Inc.

Alginate nanofibers have been attractive for potential tissue regeneration applications due to a combination of their moisture retention ability and large surface area available in a nonwoven nanofiber form. This study aims to address several challenges in alginate nanofiber application, including the lack of structural stability in aqueous environment and limited cell attachment as compared to commercial wound dressings, via examining crosslinking techniques. In addition to the commonly performed divalent ion crosslinking, a glutaraldehyde double-crosslinking step and polylysine addition were applied to an electrospun alginate nanofiber nonwoven mat. With optimization of the electrospinning solution, nanofiber morphology was maintained after the two-stage crosslinking process. Extensibility of the nanofiber mat reduced after the crosslinking process. However, both aqueous stability and cell attachment improved after the postspinning modifications, as shown through degradation tests in phosphate buffered saline solutions and fibroblast cell culture studies, respectively.

Exploring the function of interleukin (IL) 17 and related cytokine interactions have been proven useful toward understanding the role of inflammation in autoimmune diseases. Production of the inflammatory cytokine IL-23 by dendritic cells (DC's) has been shown to promote IL-17 expression by Th17 cells. It is well established that Th17 cells play an important role in several autoimmune diseases including psoriasis and alopecia. Our recent investigations have suggested that Kynurenine-rich environment can shift a pro-inflammatory response to an anti-inflammatory response, as is the case in the presence of the enzyme Indoleamine 2,3 dioxygenase (IDO), the rate-limiting enzyme in tryptophan degradation and Kynurenine (Kyn) production. In this study, we sought to explore the potential role of kynurenic acid (KynA), in modulating the expression of IL-23 and IL-17 by DCs and CD4 cells, respectively. The result of flow cytometry demonstrated that the frequency of IL-23-producing DCs is reduced with 100 µg/ml of KynA as compared with that of LPS-stimulated DCs. KynA (100 μg/ml) addition to activated T cells significantly decreased the level of IL-17 mRNA and frequency of IL-17 T cells as compared to that of concanavalin (Con) A-activated T cells. To examine the mechanism of the suppressive role of KynA on IL-23/IL-17 in these cells, cells were treated with 3 μM G-protein-coupled receptor35 (GPCR35) inhibitor (CID), for 60 min. The result showed that the reduction of both adenylate cyclase (AC) and cyclic adenosine monophosphate (cAMP) by KynA is involved in suppression of LPS-induced IL-23p19 expression. Since GPCR35 is also detected on T cells; therefore, it is concluded that KynA plays an important role in modulating the expression of IL-23 and IL-17 in DCs and Th17 cells through inhibiting GPCR35 and downregulation of both AC and cAMP.