Scar Components Research Articles

Administration of methylprednisolone do not affect the spinal scar component of spinal cord injury

Objective The aim of this study is to evaluate the impact of methylprednisolone (MP) on scar composition following spinal cord injury (SCI). Design A total of 40 adult Sprague Dawley rats underwent right hemisection injuries to the spinal cord. Interventions The rats were randomly divided into two groups: the vehicle group and the MP group. In the MP group, rats received intraperitoneal injections of MP at a dose of 30 mg/kg for 7 consecutive days, while the vehicle group received intraperitoneal injections of saline as a control. Weekly assessments of hindlimb performance in the rat models were conducted using the Basso–Beattie–Bresnahan test (BBB) score and the horizontal ladder-walking test. Changes in scar components were identified through immunofluorescence staining, and an axonal regeneration assay was employed to evaluate regrowth under inhibitory conditions. Results The administration of MP led to a significant improvement in BBB scores compared to the control group at 7 days post-injury, although this improvement was not consistent. Furthermore, rats in the MP group did not demonstrate progressive improvement in horizontal ladder walking. Notably, there were no significant changes in the content of scar components in the injured area following MP treatment, and the axon length of neurons treated with MP did not exhibit significant extension compared to the vehicle group. Conclusions Our findings indicate that the administration of MP does not effectively enhance hindlimb motor function or promote neuronal axon growth within a scarred environment after SCI.

Serum Amyloid P Attenuates Hypertrophic Scarring in Large Animal Models

IntroductionThis study's purpose was to (1)determine the effect of locally administered serum amyloid P (SAP) on the development of hypertrophic scars (HTS) in porcine and rabbit HTS models and (2)determine the pharmacokinetics of systemically administered SAP and its effect on circulating fibrocyte quantities. MethodsTwo large animal (New Zealand White Rabbit and Female Red Duroc Pigs) HTS models were utilized to study the effects of daily local injections of SAP immediately post wounding (x5 d in rabbits; x7 d in pigs) on HTS development as measured by scar elevation index , scar area, wound closure, and molecular expression studies of scar components. For SAP pharmacokinetics, total and human SAP levels in porcine blood were measured at regular intervals following intravenous administration of human SAP. Fibrocyte quantities were determined prior to and 1 h following human SAP intravenous administration. ResultsIn the rabbit model, local SAP significantly decreased the level of tissue inhibitor of metalloproteinases-1 mRNA expression and maintained matrix mettaloproteinase-9 expression, while control and vehicle groups significantly declined. In the pig model, there was a significant decrease in the trend of scar elevation indexes treated with local SAP versus controls over the study period. This decrease was statistically significant at days 14 and 84. Human SAP administered intravenously is degraded within 24 h and does not influence circulating fibrocyte quantities. ConclusionsThis is the first study to demonstrate attenuation of HTS formation using locally administered SAP in large animal HTS models. Local SAP administration reduces HTS formation by maintaining matrix mettaloproteinase-9 and decreasing tissue inhibitor of metalloproteinases-1. Intravenous administration of SAP is not as effective.

Advanced 3D analysis of fibrotic ring-like pattern in non-ischemic cardiomyopathy predicts major arrhythmic events

Abstract Funding Acknowledgements Type of funding sources: Public Institution(s). Main funding source(s): This work was supported by the National Institute for Health Research Biomedical Research Centre at Guy’s and St. Thomas’ Trust and King’s College, the Centre of Excellence in Medical Engineering funded by the Wellcome Trust and Engineering and Physical Sciences Research Council (EPSRC; WT088641/Z/09/Z). M.J.B. is supported by a Medical Research Council New Investigator Grant (MR/N011007/1) and British Heart Foundation (Project grant PG/18/74/34077). This work was supported by EPSRC 2018/19 DTP - EP/R513064/1 grant. This work was supported by a National Heart and Lung Institute Foundation grant awarded to Professor Sanjay Prasad and Dr Richard Jones. This work was supported by a National Heart and Lung Institute Foundation grant awarded to SKP, DJH, REJ, UT and BPH. Additionally, the study was supported by an Intermediate Clinical Research Fellowship awarded to BPH (FS/ICRF/21/26019). Background The presence of ring-like patterns of mid-wall fibrosis identified on late gadolinium enhancement (LGE) cardiac magnetic resonance (CMR) is associated with an increased risk of major arrhythmic events (MAE) in non-ischemic cardiomyopathy (NICM). Analysis of tissue bordering core fibrosis and healthy myocardium (Gray Zone [GZ]) has been suggested as an important pro-arrhythmic substrate in this population. Purpose To investigate refined anatomical definitions of the fibrotic ring pattern, including the importance of GZ inclusion in the association with MAE in NICM. Methods LGE CMR data from 292 NICM patients were analysed to delineate both core and GZ fibrosis. Fibrosis quantification masks for each 2D image slice were used, along with AHA 17-segment maps, to identify fibrotic ring patterns: defined by fibrosis extending by 3 or more continuous AHA-segments for any individually-contiguous fibrotic component within each slice (Fig 1A). Ring patterns were assessed separately for core fibrosis and core + GZ, as well as individually in basal, mid-basal and mid-apical regions. In separate analysis, LGE contours were aligned, interpolated, and used to generate 3D computational volumetric models (Fig 1B). Individually-connected scar components were extracted and the 3D circumferential angular variation (3DCAV) of each separate fibrotic structure quantified as a continuous variable (Fig 1C). Association of the presence of ring patterns and 3DCAV with a composite MAE were investigated. Results Of 292 patients, 67(23%) had core fibrotic ring patterns (54 basal, 28 mid-cavity level, 6 apical). Over a median(IQR) of 6(4) years, 16(24%) patients experienced MAE. On univariate Cox analysis, ring pattern core fibrosis was a strong predictor of MAE (Hazard ratio [HR] 2.2, 95% confidence interval [CI] 1.13-4.31, p=0.021). Apical-basal region analysis showed that basal ring pattern was associated with MAE (HR 2.25, 95%CI, 1.13-4.51, p=0.022). Multivariate Cox analysis including raised NYHA Class and severely reduced LVEF, overall ring (HR 2.14, 95%CI, 1.05-4.33, p=0.035) and basal ring pattern (HR 2.9, 95%CI 1.39-6.02, P=0.004) continued to show independent association with the MAE. Analysis of the full 3D geometry of the individual scar components also showed that our novel 3DCAV metric was associated with the MAE on both univariate (HR 1.31, 95%CI 1.08-1.59, P=0.007) and multivariate (HR 1.3, 95%CI, 1.06-1.60, P=0.013). Analysis of core ring patterns outperformed analysis of core+GZ patterns in all cases. Conclusions Our study confirms that ring-like patterns of fibrosis in NICM are strongly associated with MAE in NICM, with patterns predominantly at the basal regions conferring enhanced risk relative to mid-basal and mid-apical regions. Inclusion of GZ quantification in ring-pattern analysis did not enhance risk prediction. Our novel 3D analysis of circumferential fibrosis patterns may provide a more robust quantitative metric for stratification.

Therapeutic administration of mouse mast cell protease 6 improves functional recovery after traumatic spinal cord injury in mice by promoting remyelination and reducing glial scar formation.

Traumatic spinal cord injury (SCI) most often leads to permanent paralysis due to the inability of axons to regenerate in the adult mammalian central nervous system (CNS). In the past, we have shown that mast cells (MCs) improve the functional outcome after SCI by suppressing scar tissue formation at the lesion site via mouse mast cell protease 6 (mMCP6). In this study, we investigated whether recombinant mMCP6 can be used therapeutically to improve the functional outcome after SCI. Therefore, we applied mMCP6 locally via an intrathecal catheter in the subacute phase after a spinal cord hemisection injury in mice. Our findings showed that hind limb motor function was significantly improved in mice that received recombinant mMCP6 compared with the vehicle-treated group. In contrast to our previous findings in mMCP6 knockout mice, the lesion size and expression levels of the scar components fibronectin, laminin, and axon-growth-inhibitory chondroitin sulfate proteoglycans were not affected by the treatment with recombinant mMCP6. Surprisingly, no difference in infiltration of CD4+ T cells and reactivity of Iba-1+ microglia/macrophages at the lesion site was observed between the mMCP6-treated mice and control mice. Additionally, local protein levels of the pro- and anti-inflammatory mediators IL-1β, IL-2, IL-4, IL-6, IL-10, TNF-α, IFNγ, and MCP-1 were comparable between the two treatment groups, indicating that locally applied mMCP6 did not affect inflammatory processes after injury. However, the increase in locomotor performance in mMCP6-treated mice was accompanied by reduced demyelination and astrogliosis in the perilesional area after SCI. Consistently, we found that TNF-α/IL-1β-astrocyte activation was decreased and that oligodendrocyte precursor cell (OPC) differentiation was increased after recombinant mMCP6 treatment in vitro. Mechanistically, this suggests effects of mMCP6 on reducing astrogliosis and improving (re)myelination in the spinal cord after injury. In conclusion, these data show for the first time that recombinant mMCP6 is therapeutically active in enhancing recovery after SCI.

LIVE Procedure - A Bespoke Technique for Ischemic Heart Failure

<h3>Purpose</h3> Ischemic cardiomyopathy is the most common cause of heart failure (HF). In patients with left ventricular (LV) dilatation, low ejection fraction (EF) and transmural scar, Less Invasive Ventricular Enhancement (LIVE procedure) is a therapeutic option. LIVE is a unique minimal invasive intervention to exclude scarred myocardium, reduce volumes and reshape the LV, while improving HF symptoms. The procedure can be tailored to the unique characteristics of individual scar morphology. <h3>Methods</h3> We herein report 2 cases that highlight this therapy's scope of applicability. <h3>Results</h3> First patient is a 69 year-old male with a mid anterior wall and apical myocardial infarct (MI), which resulted in a dyskinetic scar. Despite guideline-directed medial therapy (GDMT), he was in NYHA class III. Cardiac CT showed a dilated heart with a LV end-systolic volume index (LVESVI) of 82 mL/m² and an EF of 24%. Due to recurrent ventricular tachycardia (VT), he underwent endocardial ablation. However, persistent slow VT's were shown during follow-up. As such, he underwent successful LIVE procedure using 3 Revivent TC™ (BioVentrix™) surgically applied anchors combined with epicardial cryoablation using the Atricure™ CryoICE™, improving his LVESVI to 52 mL/m² (-37%) and EF to 33% (+38%). Post-operative (PO) course was uneventful and follow-up defibrillator interrogation showed no sign of VT's. NYHA class improved to class I. Second patient is a 62 year-old male who suffered a previous osteal left anterior descending artery MI. This has resulted in extreme LV remodeling, with a LVESVI of 162 mL/m2 and EF of 18% by CT, due to a large highly transmural scar. Despite GDMT, he was in NYHA III. As there was an important septal scar component, he underwent hybrid LIVE procedure with Revivent TC™ system (RV-LV). 5 anchor pairs were used, including 1 internal anchor, 1 Antonius stitch (external RV-LV) and 3 LV-LV anchor pairs. PO course was straightforward and he was discharged on PO day #6. Follow-up CT showed a LVESVI of 60 mL/m2 (-63%), an EF of 44% (+151%) and full scar exclusion. <h3>Conclusion</h3> Hybrid LV reshaping and volume reduction is a safe and effective option in patients with symptomatic HF after MI. The procedure is highly customizable and adaptable to each patient's scar morphology. Additionally, concomitant procedures are possible, as described above, making of this therapy a valuable tool in the HF therapeutic armamentarium.

Extracellular Matrix and Oxidative Stress Following Traumatic Spinal Cord Injury: Physiological and Pathophysiological Roles and Opportunities for Therapeutic Intervention.

Significance: Traumatic spinal cord injury (SCI) causes significant disruption to neuronal, glial, vascular, and extracellular elements. The spinal cord extracellular matrix (ECM) comprises structural and communication proteins that are involved in reparative and regenerative processes after SCI. In the healthy spinal cord, the ECM helps maintain spinal cord homeostasis. After SCI, the damaged ECM limits plasticity and contributes to inflammation through the expression of damage-associated molecules such as proteoglycans. Recent Advances: Considerable insights have been gained by characterizing the origins of the gliotic and fibrotic scars, which not only reduce the spread of injury but also limit neuroregeneration. These properties likely limit the success of therapies used to treat patients with SCI. The ECM, which is a major contributor to the scars and normal physiological functions of the spinal cord, represents an exciting therapeutic target to enhance recovery post-SCI. Critical Issue: Various ECM-based preclinical therapies have been developed. These include disrupting scar components, inhibiting activity of ECM metalloproteinases, and maintaining iron homeostasis. Biomaterials have also been explored. However, the majority of these treatments have not experienced successful clinical translation. This could be due to the ECM and scars' polarizing roles. Future Directions: This review surveys the complexity involved in spinal ECM modifications, discusses new ECM-based combinatorial strategies, and explores the biomaterials evaluated in clinical trials, which hope to introduce new treatments that enhance recovery after SCI. These topics will incorporate oxidative species, which are both beneficial and harmful in reparative and regenerative processes after SCI, and not often assessed in pertinent literature. Antioxid. Redox Signal. 37, 184-207.

Effect of papaverine on axonal outgrowth of primary retinal ganglion cells of Sprague Dawley rats

Increasing the level of cyclic adenosine 3, 5′-monophosphate is an important mechanism for axon outgrowth and recovery of central nervous system function. This study aimed to investigate the effects of papaverine, a non-specific phosphodiesterase inhibitor, on axon outgrowth of primary retinal ganglion cells from Sprague Dawley rats. Experiments were performed on primary retinal ganglion cells extracted from Sprague Dawley rat pups within 48–72 h of birth. At 24 h after seeding, immunofluorescence was used to identify and calculate the purity of retinal ganglion cells isolated by an improved two-step immunopanning method developed by author Sujia Ma. The effects of a range of papaverine concentrations on axon outgrowth of primary retinal ganglion cells cultures were observed by immunofluorescence and measured by ImageJ software at three different time points: 24, 48, and 72 h. The ability of papaverine to enable retinal ganglion cells to overcome the inhibitory effects of glial scar component chondroitin sulfate proteoglycans was examined using chondroitin sulfate proteoglycans-coated culture plates. Rp-adenosine 3′,5′-cyclic monophosphorothioate triethylammonium salt, a blocking agent of cyclic adenosine 3, 5′-monophosphate, and dibutyryl cyclic adenosine 3, 5′-monophosphate, an analogue of cyclic adenosine 3, 5′-monophosphate, were used to explore the mechanism of papaverine in promoting retinal ganglion cells axon outgrowth. Our study shows 2 μg/mL papaverine concentration significantly promoted axon outgrowth in primary retinal ganglion cells and restored axon outgrowth of these cells on chondroitin sulfate proteoglycans. Axon outgrowth was blocked by Rp-adenosine 3′,5′-cyclic monophosphorothioate triethylammonium salt and obviously promoted by dibutyryl cyclic adenosine 3, 5′-monophosphate. Our study is the first to describe the use of papaverine to promote axon outgrowth of retinal ganglion cells. These results may help to expand the application of papaverine, and they provide a cytological basis for papaverine in the treatment of optic nerve injury caused by glaucoma and other diseases.

Deciphering glial scar after spinal cord injury.

Spinal cord injury (SCI) often leads to permanent disability, which is mainly caused by the loss of functional recovery. In this review, we aimed to investigate why the healing process is interrupted. One of the reasons for this interruption is the formation of a glial scar around the severely damaged tissue, which is usually covered by reactive glia, macrophages and fibroblasts. Aiming to clarify this issue, we summarize the latest research findings pertaining to scar formation, tissue repair, and the divergent roles of blood-derived monocytes/macrophages, ependymal cells, fibroblasts, microglia, oligodendrocyte progenitor cells (OPCs), neuron-glial antigen 2 (NG2) and astrocytes during the process of scar formation, and further analyse the contribution of these cells to scar formation. In addition, we recapitulate the development of therapeutic treatments targeting glial scar components. Altogether, we aim to present a comprehensive decoding of the glial scar and explore potential therapeutic strategies for improving functional recovery after SCI.

TGFβ1 orchestrates renal fibrosis following Escherichia coli pyelonephritis.

Renal scarring after pyelonephritis is linked to long‐term health risks for hypertension and chronic kidney disease. Androgen exposure increases susceptibility to, and severity of, uropathogenic Escherichia coli (UPEC) pyelonephritis and resultant scarring in both male and female mice, while anti‐androgen therapy is protective against severe urinary tract infection (UTI) in these models. This work employed androgenized female C57BL/6 mice to elucidate the molecular mechanisms of post‐infectious renal fibrosis and to determine how these pathways are altered by the presence of androgens. We found that elevated circulating testosterone levels primed the kidney for fibrosis by increasing local production of TGFβ1 before the initiation of UTI, altering the ratio of transcription factors Smad2 and Smad3 and increasing the presence of mesenchymal stem cell (MSC)‐like cells and Gli1 + activated myofibroblasts, the cells primarily responsible for deposition of scar components. Increased production of TGFβ1 and aberrations in Smad2:Smad3 were maintained throughout the course of infection in the presence of androgen, correlating with renal scarring that was not observed in non‐androgenized female mice. Pharmacologic inhibition of TGFβ1 signaling blunted myofibroblast activation. We conclude that renal fibrosis after pyelonephritis is exacerbated by the presence of androgens and involves activation of the TGFβ1 signaling cascade, leading to increases in cortical populations of MSC‐like cells and the Gli1 + activated myofibroblasts that are responsible for scarring.

Targeting miR-106-3p facilitates functional recovery via inactivating inflammatory microglia and interfering glial scar component deposition after neural injury.

The aim of this study was to elucidate whether the knockdown of microRNA-106-3p (miR-106-3p) could mediate the nerve regeneration and functional recovery after the spinal cord injury (SCI) and its potential mechanism. Microglia were extracted from the cerebral cortex of the neonatal rats and cultured in vitro. Subsequently, biomarkers of M1-type and M2-type in microglia transfected with miR-106-3p inhibitor were measured. Furthermore, in vivo SCI model in rats was successfully constructed, and SCI rats were intrathecally injected with miR-106-3p inhibitor or negative control. The expressions of the pro-inflammatory factors in the SCI rats or controls were detected by the enzyme-linked immunosorbent assay (ELISA). The glial scar marker and extracellular matrix were visualized by Western blotting and immunofluorescence, respectively. To observe the nerve function in rats, the movement evaluation was conducted using Basso-Beattie-Bresnahan (BBB) locomotor rating scale. In the inflammatory microglia, miR-106-3p was markedly up-regulated. Western blotting exhibited the downregulation of M1-type cells and the upregulation of M2-type cells after silencing miR-106-3p. In SCI rats, we discovered that the miR-106-3p level in the injured spinal cord was up-regulated within one week following injury. Meanwhile, the levels of the pro-inflammatory factors were significantly reduced in SCI rats with the miR-106-3p knockdown. At 7 days after the injury, the area of the astrocyte scar in the injured spinal cord was remarkably reduced by in vivo knockdown of miR-106-3p. Moreover, the extracellular matrix components secreted in the scar were also significantly inhibited. However, the glial secretion of the neurotrophic factors relatively increased in the SCI rats with the miR-106-3p knockdown. Neurological function recovery was pronounced in SCI rats with the miR-106-3p knockdown relative to controls. The silence of miR-106-3p promotes the recovery of the locomotor function and protects the environment of the neurotization by inactivating inflammatory microglia and reducing the scar formation following SCI.

Safety and Efficacy of Rose Bengal Derivatives for Glial Scar Ablation in Chronic Spinal Cord Injury.

There are no effective therapies available currently to ameliorate loss of function for patients with spinal cord injuries (SCIs). In addition, proposed treatments that demonstrated functional recovery in animal models of acute SCI have failed almost invariably when applied to chronic injury models. Glial scar formation in chronic injury is a likely contributor to limitation on regeneration. We have removed existing scar tissue in chronically contused rat spinal cord using a rose Bengal-based photo ablation approach. In this study, we compared two chemically modified rose bengal derivatives to unmodified rose bengal, both confirming and expanding on our previously published report. Rats were treated with unmodified rose bengal (RB1) or rose bengal modified with hydrocarbon (RB2) or polyethylene glycol (RB3), to determine the effects on scar components and spared tissue post-treatment. Our results showed that RB1 was more efficacious than RB2, while still maintaining minimal collateral effects on spared tissue. RB3 was not taken up by the cells, likely because of its size, and therefore had no effect. Treatment with RB1 also resulted in an increase in serotonin eight days post-treatment in chronically injured spinal cords. Thus, we suggest that unmodified rose Bengal is a potent candidate agent for the development of a therapeutic strategy for scar ablation in chronic SCI.

Inducible knockdown of procollagen I protects mice from liver fibrosis and leads to dysregulated matrix genes and attenuated inflammation

Organ fibrosis is characterized by a chronic wound-healing response, with excess deposition of extracellular matrix components. Here, collagen type I represents the most abundant scar component and a primary target for antifibrotic therapies. Liver fibrosis can progress to cirrhosis and primary liver cancer, which are the major causes of liver related morbidity and mortality. However, a (pro-)collagen type I specific therapy remains difficult and its therapeutic abrogation may incur unwanted side effects. We therefore designed tetracycline-regulated procollagen alpha1(I) short hairpin (sh)RNA expressing mice that permit a highly efficient inducible knockdown of the procollagen alpha1(I) gene in activated (myo-)fibroblasts, to study the effect of induced procollagen type I deficiency. Transgenic mice were generated using recombinase-mediated integration in embryonic stem cells or zinc-finger nuclease-aided genomic targeting combined with miR30-shRNA technology. Liver fibrosis was induced in transgenic mice by carbon tetrachloride, either without or with doxycycline supplementation. Doxycycline treated mice showed an 80–90% suppression of procollagen alpha1(I) transcription and a 40–50% reduction in hepatic collagen accumulation. Procollagen alpha1(I) knockdown also downregulated procollagens type III, IV and VI and other fibrosis related parameters. Moreover, this was associated with an attenuation of chronic inflammation, suggesting that collagen type I serves not only as major scar component, but also as modulator of other collagens and promoter of chronic inflammation.

Abstract WMP38: Inhibition of Rip1 Kinase Improves Brain Functional Recovery After Ischemic Stroke via Reducing Astrocytic Scar Formation

During the recovery phase of ischemic stroke, one of the major barriers for the spontaneous neuronal axon regeneration is the formation of astrogliosis and glial scar, and targeting astrogliosis becomes a therapeutic strategy for ischemic stroke. However, the mechanism regulating the process of scar components after ischemia still remains poorly understood. The aim of this study was to observe the role of RIP1 kinase (RIP1K), the key regulator of necroptosis (programmed necrosis) in the brain functional recovery after ischemic stroke and in the ischemic stroke-induced astrogliosis and glial scar formation in both in vitro and in vivo glial scar models. The glial scar formation model in vitro or in vivo was established by using primary cultured astrocyte subjected to 6 hours of oxygen-glucose deprivation (OGD) following 12 hours or 24 hours reperfusion, or by 90 min of transient middle cerebral artery occlusion (tMCAO) and reperfusion in rats. Western blotting analysis and immunohistochemical assay showed that knockdown of RIP1K by lentivirally-delivered shRNAs against RIP1K (shRNA RIP1K) could decrease several protein levels of glial scar markers such as glial fibillary acidic protein (GFAP), neurocan and phosphacan both in in vitro and in vivo glial scar models. Furthermore, western blotting analysis showed that knockdown of RIP1K reduced the protein levels of VEGF-D receptor 3 in in vitro glial scar models. In addition, knockdown of RIP1K also notably reduced the shrinking volume and ameliorated the behavioral symptoms in the recovery phase of rats after tMCAO. And immunocytochemistry assay demonstrated that RIP1K knockdown promoted the neuronal axonal generation in a neuron and astrocyte co-culture system. Our data indicates that RIP1K might play an important role in the formation of glial scar after ischemic stroke via promoting the function of VEGF-D receptor 3 in astrocytes.

Curcumin inhibits glial scar formation by suppressing astrocyte-induced inflammation and fibrosis in vitro and in vivo

Spinal cord injury (SCI) leads to glial scar formation by astrocytes, which severely hinders neural regeneration. Curcumin (cur) can inhibit glial scar formation, but the underlying mechanism is not fully understood. Using both in vivo and in vitro experiments, the current study investigated the phenotypic transformation of astrocytes following cur and siRNA intervention during the processes of inflammation and fibrosis and determined details of the relationship between cur treatment and the glial scar components GFAP and CSPG. We found that cur and NF-κb p65 siRNA could inhibit astrocyte activation through suppressing NF-κb signaling pathway, which led to down-regulate the expression of chemokines MCP-1, RANTES and CXCL10 released by astrocytes and decreased macrophage and T-cell infiltration, thus reducing the inflammation in the glial scar. In addition, silencing SOX-9 may reduce the deposition of extracellular matrix CSPG; whereas its over-expression could increase the CSPG expression. Cur suppressedSOX-9-inducedCSPG deposition, reduced α-SMA (an important symbol of fibrosis) expression in astrocytes, altered astrocyte phenotype, and inhibited glial scar formation by regulating fibrosis. This study confirmed that cur could regulate both the NF-κb and SOX9 signaling pathways and reduce the expression of intracellular and extracellular glial scar components through dual-target regulating both inflammation and fibrosis after SCI in the rat. This study provides an important hypothesis centered on the dual inhibition of intracellular and extracellular glial scar components as a treatment strategy for SCI.

Cyclic AMP signaling restricts activation and promotes maturation and antioxidant defenses in astrocytes.

BackgroundcAMP signaling produces dramatic changes in astrocyte morphology and physiology. However, its involvement in phenotype acquisition and the transcriptionally mediated mechanisms of action are largely unknown.ResultsHere we analyzed the global transcriptome of cultured astroglial cells incubated with activators of cAMP pathways. A bulk of astroglial transcripts, 6221 annotated genes, were differentially regulated by cAMP signaling. cAMP analogs strongly upregulated genes involved in typical functions of mature astrocytes, such as homeostatic control, metabolic and structural support to neurons, antioxidant defense and communication, whereas they downregulated a considerable number of proliferating and immaturity-related transcripts. Moreover, numerous genes typically activated in reactive cells, such as scar components and immunological mediators, were repressed by cAMP. GSEA analysis contrasting gene expression profiles with transcriptome signatures of acutely isolated astrocytes and in situ evaluation of protein levels in these cells showed that cAMP signaling conferred mature and in vivo–like transcriptional features to cultured astrocytes.ConclusionsThese results indicate that cAMP signaling is a key pathway promoting astrocyte maturation and restricting their developmental and activation features. Therefore, a positive modulation of cAMP signaling may promote the normal state of differentiated astrocytes and favor the protection and function of neuronal networks.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-016-2623-4) contains supplementary material, which is available to authorized users.

Automated Identification and Quantification of Subretinal Fibrosis in Neovascular Age-Related Macular Degeneration Using Polarization-Sensitive OCT.

To identify and quantify subretinal fibrosis in eyes with advanced neovascular age-related macular degeneration (nAMD) using polarization-sensitive optical coherence tomography (PS-OCT). Eyes of patients with subretinal fibrosis secondary to nAMD were included in this case series. All patients underwent a complete ophthalmic examination to clearly identify advanced nAMD lesions with fibrosis. Examinations of PS-OCT were performed using a novel system with an integrated eye tracker. Areas of fibrosis in PS-OCT, automatically segmented using a custom-built algorithm, were compared with conventional imaging modalities including spectral-domain OCT, fluorescein angiography, and color fundus photography in their potential to visualize fibrosis in nAMD. Fifteen eyes of 15 consecutive patients were included. In polarization-sensitive OCT B-scans, a distinct "column-like" pattern was observed in averaged axis orientation images. En face analysis provided a precise mapping of the fibrotic scar component. Fibrous tissue was selectively identified by PS-OCT based on birefringence in all lesions, whereas in SD-OCT, subretinal hyperreflective material (SHRM) could not be further classified into scar tissue, fibrovascular material, or other AMD-specific material. Based on simultaneous polarization analyses in PS-OCT, the level of RPE alteration could be evaluated as well, showing thinning and loss of RPE associated with subretinal fibrosis. Using PS-OCT, subretinal fibrosis can be identified as an intrinsically birefringent structure and can be segmented based solely on tissue-specific contrast. Polarization-sensitive OCT offers a unique method to identify clinically relevant components of SHRM (i.e., neovascular tissue versus fibrous tissue) and therefore allows for an optimized disease management and evaluation of therapeutic strategies.

Mast cells promote scar remodeling and functional recovery after spinal cord injury via mouse mast cell protease 6.

An important barrier for axon regeneration and recovery after traumatic spinal cord injury (SCI) is attributed to the scar that is formed at the lesion site. Here, we investigated the effect of mouse mast cell protease (mMCP) 6, a mast cell (MC)-specific tryptase, on scarring and functional recovery after a spinal cord hemisection injury. Functional recovery was significantly impaired in both MC-deficient and mMCP6-knockout (mMCP6(-/-)) mice after SCI compared with wild-type control mice. This decrease in locomotor performance was associated with an increased lesion size and excessive scarring at the injury site. Axon growth-inhibitory chondroitin sulfate proteoglycans and the extracellular matrix components fibronectin, laminin, and collagen IV were significantly up-regulated in MC-deficient and mMCP6(-/-) mice, with an increase in scar volume between 23 and 32%. A degradation assay revealed that mMCP6 directly cleaves fibronectin and collagen IV in vitro In addition, gene expression levels of the scar components fibronectin, aggrecan, and collagen IV were increased up to 6.8-fold in mMCP6(-/-) mice in the subacute phase after injury. These data indicate that endogenous mMCP6 has scar-suppressing properties after SCI via indirect cleavage of axon growth-inhibitory scar components and alteration of the gene expression profile of these factors.-Vangansewinkel, T., Geurts, N., Quanten, K., Nelissen, S., Lemmens, S., Geboes, L., Dooley, D., Vidal, P. M., Pejler, G., Hendrix, S. Mast cells promote scar remodeling and functional recovery after spinal cord injury via mouse mast cell protease 6.

Role of endogenous neural stem cells in spinal cord injury and repair.

Spinal cord injury is followed by glial scar formation, which has positive and negative effects on recovery from the lesion. More than half of the astrocytes in the glial scar are generated by ependymal cells, the neural stem cells in the spinal cord. We recently demonstrated that the neural stem cell-derived scar component has several beneficial functions, including restricting tissue damage and neural loss after spinal cord injury. This finding identifies endogenous neural stem cells as a potential therapeutic target for treatment of spinal cord injury.

Reliability of scar assessments performed with an integrated skin testing device – The DermaLab Combo®

BackgroundThe DermaLab Combo® is a device with potential to make objective measurements of key scar components – pigmentation, vascularity, pliability and thickness. This study assessed the inter-rater and test–retest reliability of these measurements. MethodThree raters performed scar assessments on thirty patients with burn scars using the DermaLab Combo®. Measurements of pigmentation, vascularity, pliability and thickness were made and intra-class correlation coefficients (ICC) were derived for inter-rater and test–retest reliability. ResultsInter-rater reliability was found to be “excellent” in the ‘best’ and ‘worst’ areas of the index scar and normal skin for pigmentation (ICC: 0.94–0.98) and thickness (ICC: 0.86–0.96). Test–retest reliability was also “excellent” for pigmentation (ICC: 0.87–0.89) and thickness (ICC: 0.92–0.97) in all areas. Vascularity showed “good” to “excellent” inter-rater reliability (ICC: 0.66–0.84) in all areas however test–retest reliability was “low” (ICC: 0.29–0.42). Test–retest reliability was “excellent” for pliability (ICC: 0.76–0.91). Technical limitations were encountered making measurements in some scars for thickness, and in particular, pliability. ConclusionThe DermaLab Combo® measured pigmentation, thickness and pliability with “excellent” reliability. If future studies provide protocols to improve test–retest reliability of vascularity measurements and obtain pliability measurements more successfully, the DermaLab Combo® will be valuable device for scar assessment.

3D delayed enhancement magnetic resonance sequences improve conducting channel delineation prior to ventricular tachycardia ablation

Introduction: Delayed enhanced cardiac magnetic resonance using 2D sequences (CMR-2D) represents the standard for clinical characterization of myocardium. However, 2D images suffer from insufficient spatial resolution in the Z-axis and missregistration that preclude appropriate visualization of conducting channels (CC), which are critical for ventricular tachycardia (VT) ablation. We studied whether characterization using a free breathing 3D delayed enhanced navigator gated sequence (CMR-3D) proved to be superior than CMR-2D sequences. Methods: We included 30 consecutive patients with structural heart disease referred for VT ablation. Myocardial characterization was conducted prior to the ablation procedure in a 3T-scanner using CMR-2D and CMR-3D sequences, yielding a spatial resolution of 1.4 x 1.4 x 5 mm and 1.4 x 1.4 x 1.4 mm respectively. The scar components, core and border zone (BZ), were quantified in both datasets using the 60% and 40% threshold of maximum pixel intensity, respectively. The signal to noise ratio (SNR) and contrast to noise ratio (CNR) was analyzed in a representative slice in both sequences. For both set of images a 3D reconstruction of the scar was obtained and an electrophysiologyst identified potential CC and compared them to those depicted in the electroanatomic map (EAM). Results: We found no significant differences between the mass of the scar core in the 2D and 3D sequence (mean 7.33±6.56 vs 6.74±5.22 grams respectivelly, p=0.612). However, the BZ mass was smaller in the 2D than in the 3D sequence (9.38±7.72 vs 12.10±7.81 grams; p=0.019). The SNR was higher in the 2D dataset as compared to the 3D (42.93±27.34 vs 28.09±12.85; p=0.005) as well as the CNR (37.01±26.20 vs 20.15±11.41; p=0.001). The mean number of CC identified in the 3D dataset was higher than in the 2D, and closer to those depicted in the EAM (1.06±0.75 for CMR-2D vs 2.63±1.41 for EAM, p=0.005; and 2.06±1.25 for CMR-3D vs 2.63±1.41 for EAM p=0.088). Conclusion: Despite the higher SNR and CNR of standard CMR-2D images, the higher spatial resolution provided by CMR-3D images improved the overall delineation of CC prior to VT ablation.