Trimethylamine N-Oxide as a Mediator Linking Peripheral to Central Inflammation: An In Vitro Study

In this study, the plausible role of trimethylamine N-oxide (TMAO), a microbiota metabolite, was investigated as a link between peripheral inflammation and the inflammation of the central nervous system using different cell lines. TMAO treatment favored the differentiation of adipocytes from preadipocytes (3T3-L1 cell line). In macrophages (RAW 264.7 cell line), which infiltrate adipose tissue in obesity, TMAO increased the expression of pro-inflammatory cytokines. The treatment with 200 μM of TMAO seemed to disrupt the blood-brain barrier as it induced a significant decrease in the expression of occludin in hCMECs. TMAO also increased the expression of pro-inflammatory cytokines in primary neuronal cultures, induced a pro-inflammatory state in primary microglial cultures, and promoted phagocytosis. Data obtained from this project suggest that microbial dysbiosis and increased TMAO secretion could be a key link between peripheral and central inflammation. Thus, TMAO-decreasing compounds may be a promising therapeutic strategy for neurodegenerative diseases.

Serum amyloid P component accumulates and persists in neurones following traumatic brain injury

The mechanisms underlying neurodegenerative sequelae of traumatic brain injury (TBI) are poorly understood. The normal plasma protein, serum amyloid P component (SAP), which is normally rigorously excluded from the brain, is directly neurocytotoxic for cerebral neurones and also binds to Aβ amyloid fibrils and neurofibrillary tangles, promoting formation and persistence of Aβ fibrils. Increased brain exposure to SAP is common to many risk factors for dementia, including TBI, and dementia at death in the elderly is significantly associated with neocortical SAP content. Here, in 18 of 30 severe TBI cases, we report immunohistochemical staining for SAP in contused brain tissue with blood-brain barrier disruption. The SAP was localized to neurofilaments in a subset of neurones and their processes, particularly damaged axons and cell bodies, and was present regardless of the time after injury. No SAP was detected on astrocytes, microglia, cerebral capillaries or serotoninergic neurones and was absent from undamaged brain. C-reactive protein, the control plasma protein most closely similar to SAP, was only detected within capillary lumina. The appearance of neurocytotoxic SAP in the brain after TBI, and its persistent, selective deposition in cerebral neurones, are consistent with a potential contribution to subsequent neurodegeneration.

Newborns with Favourable Outcomes after Perinatal Asphyxia Have Upregulated Glucose Metabolism-Related Proteins in Plasma

Hypoxic-ischaemic encephalopathy (HIE) is an important cause of morbidity and mortality globally. Although mild therapeutic hypothermia (TH) may improve outcomes in selected babies, the mechanism of action is not fully understood. A proteomics discovery study was carried out to analyse proteins in the plasma of newborns with HIE. Proteomic analysis of plasma from 22 newborns with moderate-severe HIE that had initially undergone TH, and relative controls including 10 newborns with mild HIE who did not warrant TH and also cord blood from 10 normal births (non-HIE) were carried out using the isobaric Tandem Mass Tag (TMT®) 10plexTM labelling with tandem mass spectrometry. A total of 7818 unique peptides were identified in all TMT10plexTM samples, translating to 3457 peptides representing 405 proteins, after applying stringent filter criteria. Apart from the unique protein signature from normal cord blood, unsupervised analysis revealed several significantly regulated proteins in the TH-treated moderate-severe HIE group. GO annotation and functional clustering revealed various proteins associated with glucose metabolism: the enzymes fructose-bisphosphate aldolase A, glyceraldehyde-3-phosphate dehydrogenase, phosphoglycerate mutase 1, phosphoglycerate kinase 1, and pyruvate kinase PKM were upregulated in newborns with favourable (sHIE+) outcomes compared to newborns with unfavourable (sHIE-) outcomes. Those with favourable outcomes had normal MR imaging or mild abnormalities not predictive of adverse outcomes. However, in comparison to mild HIE and the sHIE- groups, the sHIE+ group had the additional glucose metabolism-related enzymes upregulated, including triosephosphate isomerase, α-enolase, 6-phosphogluconate dehydrogenase, transaldolase, and mitochondrial glutathione reductase. In conclusion, our plasma proteomic study demonstrates that TH-treated newborns with favourable outcomes have an upregulation in glucose metabolism. These findings may open new avenues for more effective neuroprotective therapy.

Long-chain omega-3 polyunsaturated fatty acids are reduced in neonates with substantial brain injury undergoing therapeutic hypothermia after hypoxic-ischemic encephalopathy

Hypoxic-ischemic encephalopathy (HIE) is a major cause of neonatal morbidity and mortality. Although therapeutic hypothermia is an effective treatment, substantial chronic neurological impairment often persists. The long-chain omega-3 polyunsaturated fatty acids (PUFAs), docosahexaenoic (DHA) and eicosapentaenoic (EPA) acids, offer therapeutic potential in the post-acute phase. To understand how PUFAs are affected by HIE and therapeutic hypothermia we quantified for the first time the effects of HIE and therapeutic hypothermia on blood PUFA levels and lipid peroxidation. In a cross-sectional approach, blood samples from newborns with moderate to severe HIE, who underwent therapeutic hypothermia (sHIE group) were compared to samples from newborns with mild HIE, who did not receive therapeutic hypothermia, and controls. The sHIE group was stratified into cerebral MRI predictive of good (n = 10), or poor outcomes (n = 10; nine developed cerebral palsy). Cell pellets were analyzed for fatty acid content, and plasma for lipid peroxidation products, thiobarbituric acid reactive substances and 4-hydroxy-2-nonenal. Omega-3 Index (% DHA + EPA) was similar between control and HIE groups; however, with therapeutic hypothermia there were significantly lower levels in poor vs. good prognosis sHIE groups. Estimated Δ-6 desaturase activity was significantly lower in sHIE compared to mild HIE and control groups, and linoleic acid significantly increased in the sHIE group with good prognosis. Reduced long-chain omega-3 PUFAs was associated with poor outcome after HIE and therapeutic hypothermia, potentially due to decreased biosynthesis and tissue incorporation. We speculate a potential role for long-chain omega-3 PUFA interventions in addition to existing treatments to improve neurologic outcomes in sHIE.

Correlation between initial tumor enlargement and magnetic resonance imaging characteristics following linear accelerator-based stereotactic radiosurgery for acoustic neuromas

BACKGROUND

Initial tumor enlargement (or pseudoprogression) instead of true tumor progression is a common phenomenon in patients with acoustic neuromas who are treated with stereotactic radiosurgery (SRS). This phenomenon can affect clinical decision-making and patient management. This study assessed the correlation between initial tumor enlargement and magnetic resonance imaging characteristics in patients with acoustic neuromas who were treated with linear accelerator (LINAC)-based SRS. The long-term tumor control outcomes were also analyzed.

MATERIALS AND METHODS

In total, 330 patients with sporadic acoustic neuromas who were treated with LINAC SRS between March 2006 and March 2020 were retrospectively evaluated to assess their initial tumor enlargement. The tumors were divided into homogeneously enhanced, heterogeneously enhanced, and cystic types based on the morphological characteristics noted on magnetic resonance images. Tumor control was assessed in 275 patients with a follow-up duration of more than 2 years.

RESULTS

Initial enlargement was observed in 137 of 330 (41.5%) tumors as early as 3 months after LINAC SRS. Data analysis revealed that postoperative tumors with a residual volume lower than 2.5 cm3 had a lower incidence of initial enlargement (p = 0.039). No correlation was noted between the initial enlargement and morphological characteristics of tumors. In patients with a mean follow-up duration of 82.8 ± 37.2 months, heterogeneously enhanced tumors exhibited a lower control rate than homogeneously enhanced and cystic tumors (p = 0.045). No correlation was noted between initial enlargement and tumor control.

CONCLUSION

Initial enlargement can occur as early as 3 months after SRS. Postoperative residual tumors with a volume lower than 2.5 cm3 exhibit a lower incidence of initial enlargement. Heterogeneously enhanced tumors have a lower local control rate.

Co-Delivery of Docosahexaenoic Acid and Brain-Derived Neurotropic Factor from Electrospun Aligned Core–Shell Fibrous Membranes in Treatment of Spinal Cord Injury

To restore lost functions while repairing the neuronal structure after spinal cord injury (SCI), pharmacological interventions with multiple therapeutic agents will be a more effective modality given the complex pathophysiology of acute SCI. Toward this end, we prepared electrospun membranes containing aligned core–shell fibers with a polylactic acid (PLA) shell, and docosahexaenoic acid (DHA) or a brain-derived neurotropic factor (BDNF) in the core. The controlled release of both pro-regenerative agents is expected to provide combinatory treatment efficacy for effective neurogenesis, while aligned fiber topography is expected to guide directional neurite extension. The in vitro release study indicates that both DHA and BDNF could be released continuously from the electrospun membrane for up to 50 days, while aligned microfibers guide the neurite extension of primary cortical neurons along the fiber axis. Furthermore, the PLA/DHA/BDNF core–shell fibrous membrane (CSFM) provides a significantly higher neurite outgrowth length from the neuron cells than the PLA/DHA CSFM. This is supported by the upregulation of genes associated with neuroprotection and neuroplasticity from RT-PCR analysis. From an in vivo study by implanting a drug-loaded CSFM into the injury site of a rat suffering from SCI with a cervical hemisection, the co-delivery of DHA and BDNF from a PLA/DHA/BDNF CSFM could significantly improve neurological function recovery from behavioral assessment, as well as provide neuroprotection and promote neuroplasticity changes in recovered neuronal tissue from histological analysis.

Lipid Profiles from Dried Blood Spots Reveal Lipidomic Signatures of Newborns Undergoing Mild Therapeutic Hypothermia after Hypoxic-Ischemic Encephalopathy

Hypoxic-ischemic encephalopathy (HIE) is associated with perinatal brain injury, which may lead to disability or death. As the brain is a lipid-rich organ, various lipid species can be significantly impacted by HIE and these correlate with specific changes to the lipidomic profile in the circulation. Objective: To investigate the peripheral blood lipidomic signature in dried blood spots (DBS) from newborns with HIE. Using univariate analysis, multivariate analysis and sPLS-DA modelling, we show that newborns with moderate-severe HIE (n = 46) who underwent therapeutic hypothermia (TH) displayed a robust peripheral blood lipidomic signature comprising 29 lipid species in four lipid classes; namely phosphatidylcholine (PC), lysophosphatidylcholine (LPC), triglyceride (TG) and sphingomyelin (SM) when compared with newborns with mild HIE (n = 18). In sPLS-DA modelling, the three most discriminant lipid species were TG 50:3, TG 54:5, and PC 36:5. We report a reduction in plasma TG and SM and an increase in plasma PC and LPC species during the course of TH in newborns with moderate-severe HIE, compared to a single specimen from newborns with mild HIE. These findings may guide the research in nutrition-based intervention strategies after HIE in synergy with TH to enhance neuroprotection.

Neuronal let-7b-5p acts through the Hippo-YAP pathway in neonatal encephalopathy

Despite increasing knowledge on microRNAs, their role in the pathogenesis of neonatal encephalopathy remains to be elucidated. Herein, we identify let-7b-5p as a significant microRNA in neonates with moderate to severe encephalopathy from dried blood spots using next generation sequencing. Validation studies using Reverse Transcription and quantitative Polymerase Chain Reaction on 45 neonates showed that let-7b-5p expression was increased on day 1 in neonates with moderate to severe encephalopathy with unfavourable outcome when compared to those with mild encephalopathy. Mechanistic studies performed on glucose deprived cell cultures and the cerebral cortex of two animal models of perinatal brain injury, namely hypoxic-ischaemic and intrauterine inflammation models confirm that let-7b-5p is associated with the apoptotic Hippo pathway. Significant reduction in neuronal let-7b-5p expression corresponded with activated Hippo pathway, with increased neuronal/nuclear ratio of Yes Associated Protein (YAP) and increased neuronal cleaved caspase-3 expression in both animal models. Similar results were noted for let-7b-5p and YAP expression in glucose-deprived cell cultures. Reduced nuclear YAP with decreased intracellular let-7b-5p correlated with neuronal apoptosis in conditions of metabolic stress. This finding of the Hippo-YAP association with let-7b needs validation in larger cohorts to further our knowledge on let-7b-5p as a biomarker for neonatal encephalopathy.

Using next generation sequencing of dried blood spots and subsequent validation, Ponnusamy et al identify let-7b-5p as an elevated microRNA in neonates with moderate to severe encephalopathy. Using cell culture and murine models of perinatal brain injury they demonstrate that the effects of let-7b-5p are elicited via the Hippo-YAP pathway, which should be validated in large neonate cohorts to expand our understanding of let-7b-5p as a biomarker for neonatal encephalopathy.

Alleviation of neuropathic pain by over-expressing a soluble colony-stimulating factor 1 receptor to suppress microgliosis and macrophage accumulation

Microglial proliferation and activation and macrophage accumulation are implicated in neuropathic pain development. In this study, we aim to suppress microgliosis and macrophage accumulation by over-expressing a non-functional soluble colony stimulating factor-1 receptor (sCSF1R) using an adeno-associated virus 9 vector (AAV9). AAV9/sCSF1R and the control vector AAV9/GFP were intrathecally administered into the lumbar spine of adult C57BL/6 mice. Two weeks later, these mice underwent partial sciatic nerve ligation to induce neuropathic pain. GFP and sCSF1R were highly expressed in lumbar dorsal root ganglia (DRG) and spinal cord of AAV9-injected mice. A significant increase in microglia densities in the dorsal and ventral horns of lumbar spinal cords and macrophage densities in DRG and sciatic nerves were observed in the mice with either ligation alone or pre-treated with AAV9/GFP. In nerve-ligated mice pre-treated with AAV9/sCSF1R the microglia densities in the dorsal and ventral horns and macrophage densities in DRG and sciatic nerves were significantly lower compared to nerve-ligated mice pre-treated with AAV9/GFP. Behavioral tests showed that nerve-ligated mice pre-treated with AAV9/sCSF1R had a significantly higher paw withdrawal threshold, indicating the alleviation of neuropathic pain. The results implicate that viral vector-mediated expression of sCSF1R may represent a novel strategy in the alleviation of neuropathic pain.

Raised Plasma Neurofilament Light Protein Levels After Rewarming Are Associated With Adverse Neurodevelopmental Outcomes in Newborns After Therapeutic Hypothermia

Aim: To determine the predictive value of plasma neurofilament light protein (NfL) as a prognostic marker for outcomes in babies who have undergone therapeutic hypothermia (TH) for hypoxic ischemic encephalopathy (HIE).

Method: NfL levels from three groups of term newborns were compared: (1) those with mild HIE who did not receive TH, (2) newborns treated with TH who had minimal or no brain injury on MRI, and (3) newborns treated with TH who had substantial brain injury on MRI. Follow-up outcomes were collected from 18 months onward.

Results: Follow-up was available for 33/37 (89%) of children. A cutoff NfL level >436 pg/ml after rewarming (median age 98 h) was associated with adverse outcome with a diagnostic sensitivity 75%, specificity 77%, PPV 75%, and NPV 77%. NfL levels at earlier time points were not predictive of outcome.

Interpretation: This pilot study shows that persistently raised plasma NfL levels after rewarming are associated with adverse outcomes in babies with HIE who have undergone TH.

Docosahexaenoic Acid-Loaded Polylactic Acid Core-Shell Nanofiber Membranes for Regenerative Medicine after Spinal Cord Injury: In Vitro and In Vivo Study

Spinal cord injury (SCI) is associated with disability and a drastic decrease in quality of life for affected individuals. Previous studies support the idea that docosahexaenoic acid (DHA)-based pharmacological approach is a promising therapeutic strategy for the management of acute SCI. We postulated that a nanostructured material for controlled delivery of DHA at the lesion site may be well suited for this purpose. Toward this end, we prepare drug-loaded fibrous mats made of core-shell nanofibers by electrospinning, which contained a polylactic acid (PLA) shell for encapsulation of DHA within the core, for delivery of DHA in situ. In vitro study confirmed sustained DHA release from PLA/DHA core-shell nanofiber membrane (CSNM) for up to 36 days, which could significantly increase neurite outgrowth from primary cortical neurons in 3 days. This is supported by the upregulation of brain-derived neurotropic factor (BDNF) and neurotrophin-3 (NT-3) neural marker genes from qRT-PCR analysis. Most importantly, the sustained release of DHA could significantly increase the neurite outgrowth length from cortical neuron cells in 7 days when co-cultured with PLA/DHA CSNM, compared with cells cultured with 3 μM DHA. From in vivo study with a SCI model created in rats, implantation of PLA/DHA CSNM could significantly improve neurological functions revealed by behavior assessment in comparison with the control (no treatment) and the PLA CSNM groups. According to histological analysis, PLA/DHA CSNM also effectively reduced neuron loss and increased serotonergic nerve sprouting. Taken together, the PLA/DHA CSNM may provide a nanostructured drug delivery system for DHA and contribute to neuroprotection and promoting neuroplasticity change following SCI.

Serotonin Expression in the Song Circuitry of Adult Male Zebra Finches

Serotonin is an important neurotransmitter of the brain, but its role in song control remains to be fully demonstrated. Using male zebra finches (Taeniopygia guttata) that have song learning and production capabilities, we analysed the serotonin expression levels in the song nuclei and adjacent areas (peri-song nuclei) using immunohistochemistry. Key song nuclei were identified using combinations of Hoechst, choline acetyltransferase, and a neurofilament (NN18) marker in reference to the ZEBrA atlas. Mean serotonin expression was highest in interfacial nucleus (Nif) and lower in the other song nuclei in the following order (in order of highest first): interfacial nucleus (Nif) > Area X > dorsomedial part of the intercollicular nucelus (DM) > robust nucleus of the archistriatum (RA) > lateral magnocellular nucleus of the anterior neostriatum (LMAN) > ventral respiratory group (VRG) > dorsolateral nucleus of the medial thalamus (DLM) > the nucleus HVC (proper name) > tracheosyringeal motor nucleus (nXIIts). However, the mean serotonin expression (in order of highest first) in the peri-song nuclei regions was: peri-DM > peri-nXIIts > supra-peri-HVC > peri-RA > peri-DLM > peri-Area X > infra-peri-HVC > peri-VRG > peri-LMAN > peri-Nif. Interestingly, serotoninergic fibers immunostained for serotonin or the serotonin transporter can be found as a basket-like peri-neuronal structure surrounding cholinergic cell bodies, and appear to form contacts onto dopaminergic neurones. In summary, serotonin fibers are present at discrete song nuclei, and peri-song nuclei regions, which suggest serotonin may have a direct and/or modulatory role in song control.

DHA Attenuates Cerebral Edema Following Traumatic Brain Injury via the Reduction in Blood-Brain Barrier Permeability

Traumatic brain injury (TBI) could result in edema and cause an increase in intracranial pressure of the brain resulting in mortality and morbidity. Although there is hyperosmolarity therapy available for this pathophysiological event, it remains controversial. Recently, several groups have shown docosahexaenoic acid (DHA) to improve functional and histological outcomes following brain injury based on reduction of neuroinflammation and apoptosis. However, the effect of DHA on blood-brain barrier (BBB) dysfunction after brain injury has not been fully studied. Here, a controlled cortical impact rat model was used to test the effect of a single dose of DHA administered 30 min post injury. Modified neurological severity score (mNSS) and forelimb asymmetry were used to determine the functional outcomes. Neuroimaging and histology were used to characterize the edema and BBB dysfunction. The study showed that DHA-treated TBI rats had better mNSS and forelimb asymmetry score than vehicle-treated TBI rats. Temporal analysis of edema using MRI revealed a significant reduction in edema level with DHA treatment compared to vehicle in TBI rats. Histological analysis using immunoglobulin G (IgG) extravasation showed that there was less extravasation, which corresponded with a reduction in aquaporin 4 and astrocytic metalloprotease 9 expression, and greater endothelial occludin expression in the peri-contusional site of the TBI rat brain treated with DHA in comparison to vehicle treatment. In conclusion, the study shows that DHA can exert its functional improvement by prevention of the edema formation via prevention of BBB dysfunction after TBI.

Docosahexaenoic acid reduces microglia phagocytic activity via miR-124 and induces neuroprotection in rodent models of spinal cord contusion injury

Microglia are activated after spinal cord injury (SCI), but their phagocytic mechanisms and link to neuroprotection remain incompletely characterized. Docosahexaenoic acid (DHA) has been shown to have significant neuroprotective effects after hemisection and compression SCI and can directly affect microglia in these injury models. In rodent contusion SCI, we demonstrate that DHA (500 nmol/kg) administered acutely post-injury confers neuroprotection and enhances locomotor recovery, and also exerts a complex modulation of the microglial response to injury. In rodents, at 7 days after SCI, the level of phagocytosed myelin within Iba1-positive or P2Y12-positive cells was significantly lower after DHA treatment, and this occurred in parallel with an increase in intracellular miR-124 expression. Furthermore, intraspinal administration of a miR-124 inhibitor significantly reduced the DHA-induced decrease in myelin phagocytosis in mice at 7 days post-SCI. In rat spinal primary microglia cultures, DHA reduced the phagocytic response to myelin, which was associated with an increase in miR-124, but not miR-155. A similar response was observed in a microglia cell line (BV2) treated with DHA, and the effect was blocked by a miR-124 inhibitor. Furthermore, the phagocytic response of BV2 cells to stressed neurones was also reduced in the presence of DHA. In peripheral monocyte-derived macrophages, the expression of the M1, but not the M0 or M2 phenotype, was reduced by DHA, but the phagocytic activation was not altered. These findings show that DHA induces neuroprotection in contusion injury. Furthermore, the improved outcome is via a miR-124-dependent reduction in the phagocytic response of microglia.

Refining rodent models of spinal cord injury

This report was produced by an Expert Working Group (EWG) consisting of UK-based researchers, veterinarians and regulators of animal experiments with specialist knowledge of the use of animal models of spinal cord injury (SCI). It aims to facilitate the implementation of the Three Rs (Replacement, Reduction and Refinement), with an emphasis on refinement. Specific animal welfare issues were identified and discussed, and practical measures proposed, with the aim of reducing animal use and suffering, reducing experimental variability, and increasing translatability within this critically important research field.

Prior Antiplatelet Therapy, Excluding Phosphodiesterase Inhibitor Is Associated with Poor Outcome in Patients with Spontaneous Intracerebral Haemorrhage

There is conflicting results on whether prior antiplatelet therapy (APT) is associated with poor outcome in spontaneous intracerebral haemorrhage (ICH) patients. To determine whether prior APT is associated with spontaneous ICH, and whether there is a difference between the different types of APT, including cyclooxygenase inhibitor (COX-I), adenosine diphosphate receptor inhibitor (ADP-I) and phosphodiesterase inhibitor (PDE-I). A retrospective study of patients with ICH diagnosed between 2001 and 2013 in the National Health Insurance Research Database. Baseline unbalance between APT and non-APT groups was solved by multivariable adjustment (primary analysis) and propensity score matching (sensitivity analysis). Patients with prior APT had a higher rate of in-hospital death (odds ratio [OR], 1.16; 95% confidence interval [CI], 1.09-1.23) compared to non-APT group. Compared to non-APT group, there was a greater rate of in-hospital death with spontaneous ICH with ADP-I (OR, 1.49; 95% CI, 1.24-1.79) and COX-I (OR, 1.17; 95% CI, 1.09-1.25). PDE-I exhibited no difference in in-hospital death with spontaneous ICH (OR, 1.03; 95% CI, 0.91-1.16) compared to non-APT group. Remarkably, the in-hospital mortality rate was significantly higher in the ADP-I group than in the PDE-I group (hazard ratio, 1.45; 95% CI, 1.17-1.80). In this study, ADP-I and COX-1, but not PDE-I, are the most likely contributors to the association of APT with poor outcome with spontaneous ICH patients. These findings suggest that the complexity of the different mechanism of actions of prior APT can alter the outcome in spontaneous ICH.

Studies on long term behavioural changes in group-housed rat models of brain and spinal cord injury using an automated home cage recording system

BACKGROUND

Neurotrauma patients face major neurological sequelae. The failure in the preclinical-to-clinical translation of candidate therapies could be due to poor evaluation of rodent behaviours after neurotrauma.

NEW METHOD

A home cage automated system was used to study the long term behaviour of individual rats with traumatic brain injury (TBI), spinal cord injury (SCI) and non-CNS injured controls, whilst group-housed in their home cages. Naïve rats were used as baseline controls. Automated locomotor activity and body temperature recordings were carried out 24 h /day for 3 days/week during 12 weeks post-injury. Behavioural patterns, including aggression, rearing, grooming, feeding and drinking were analysed from automated video recordings during week 1, 6 and 12.

RESULTS

SCI animals showed a lower locomotor activity compared to TBI or control animals during light and dark phases. TBI animals showed a higher aggression during the dark phase in the first week post-injury compared to SCI or control animals. Individual grooming and rearing were reduced in SCI animals compared to TBI and control animals in the first week post-injury during the dark phase. No differences in drinking or feeding were detected between groups. Locomotor activity did not differ between naïve male and female rats, but body temperature differ between light and dark phases for both.

STANDARD METHODS

Injury severity was compared to standard SCI and TBI behaviour scores (BBB and mNSS, respectively) and histological analysis.

CONCLUSIONS

This study demonstrates the practical benefits of using a non-intrusive automated home cage recording system to observe long term individual behaviour of group-housed SCI and TBI rats.

Previous Antithrombotic Therapy, Particularly Anticoagulant, Is Associated with Unfavorable Outcomes in Patients with Primary Spontaneous Intracerebral Hemorrhage Receiving Craniotomy: A Nationwide Population-Based Cohort Study

OBJECTIVE

The impact of antithrombotic agents on patients with primary intracerebral hemorrhage (ICH) remains controversial, especially patients who require emergent craniotomy. This study was undertaken to evaluate clinical outcomes in operated patients with ICH with and without previous antithrombotic agents.

METHODS

This is a retrospective cohort study. Between January 2001 and December 2013, all patients with ICH who received emergent craniotomy and who were present in Taiwan's National Health Insurance Research Database were screened and divided into those with previous antiplatelet therapy, anticoagulant therapy, and nonantithrombotic therapy according to their health care claims data within 3 months of index admission. The primary end points included in-hospital mortality and complications and short-term outcome.

RESULTS

Of 18,872 eligible patients, 16,251 (87.1%) did not receive any antithrombotic therapy, 2267 patients had antiplatelet therapy, and 354 patients had anticoagulation therapy. After propensity score matching, significantly more blood transfusions and craniectomies were identified in the patients with previous antithrombotic treatment compared with those undergoing nonantithrombotic therapy. Compared with the nonantithrombotic treatment cohort, patients under previous anticoagulant treatment had significantly higher in-hospital mortality (odds ratio, 2.12; 95% confidence interval, 1.45-3.10). Furthermore, during the 6-month follow-up period, previous anticoagulant therapy was independently associated with a greater risk of all-cause mortality (P = 0.001). The in-hospital and 6-month all-cause mortality of patients with previous antiplatelet treatment was not significantly different from patients with nonantithrombotic treatment.

CONCLUSIONS

These findings suggested an increased risk of in-hospital mortality and poor short-term outcome among operated patients with ICH with previous antithrombotic therapy, particularly anticoagulant therapy, but not with antiplatelet therapy.

The role of microRNAs in newborn brain development and hypoxic ischaemic encephalopathy

Neonates can develop hypoxic-ischaemic encephalopathy (HIE) due to lack of blood supply or oxygen, resulting in a major cause of death and disability among term newborns. However, current definitive treatment of therapeutic hypothermia, will only benefit one out of nine babies. Furthermore, the mechanisms of HIE and therapeutic hypothermia are not fully understood. Recently, microRNAs (miRNAs) have become of interest to many researchers due to their important role in post-transcriptional control and deep evolutionary history. Despite this, role of miRNAs in newborns with HIE remains largely unknown due to limited research in this field. Therefore, this review aims to understand the role of miRNAs in normal brain development and HIE pathophysiology with reliance on extrapolated data from other diseases, ages and species due to current limited data. This will provide us with an overview of how miRNAs in normal brain development changes after HIE. Furthermore, it will indicate how miRNAs are affected specifically or globally by the various pathophysiological events. In addition, we discuss about how drugs and commercially available agents can specifically target certain miRNAs as a mechanism of action and potential safety issue with off-target effects. Improving our understanding of the role of miRNAs on the cellular response after HIE would enhance the success of effective diagnosis, prognosis, and treatment of newborns with HIE.

Increased expression of colony-stimulating factor-1 in mouse spinal cord with experimental autoimmune encephalomyelitis correlates with microglial activation and neuronal loss

Microglia contribute to pathophysiology at all stages of multiple sclerosis. Colony-stimulating factor-1 (CSF1) is crucial for microglial proliferation and activation. In this study we measured the CSF1 levels and studied its cellular expression in the mouse spinal cords with experimental autoimmune encephalomyelitis (EAE) to explore the potential contribution of CSF1 in neuronal death. ELISA data showed that CSF1 levels were significantly higher in the spinal cords with acute and chronic EAE than those of normal and adjuvant-injected mice. Immunohistochemical studies demonstrated that CSF1 was expressed in astrocytes and neurons in normal mouse spinal cord. In acute EAE, CSF1 expression was significantly increased, especially in astrocytes in peripheral white matter and large motoneurons. High density of activated microglia was observed in the gray matter where motoneurons expressed high-level CSF1 in acute EAE. Significant large motoneuron loss was seen in chronic EAE and the remaining motoneurons with high-level CSF1 were enwrapped by microglia. Viral vector mediated over-expression of CSF1 in spinal neurons induced profound proliferation and activation of microglia at the injection site and microglia enwrapped CSF1-transduced neurons and their neurites. Significant loss of large CSF1-transduced neurons was seen at 2 and 3 weeks post-viral injection. Demyelination in the CSF1-transduced areas was also significant. These results implicate that CSF1 upregulation in CNS may play an important role in the proliferation and activation of microglia in EAE, contributing to neuroinflammation and neurodegeneration. © 2018 Wiley Periodicals, Inc.

Raised Plasma Neurofilament Light Protein Levels Are Associated with Abnormal MRI Outcomes in Newborns Undergoing Therapeutic Hypothermia

Aims and hypothesis

Hypoxic-ischemic encephalopathy (HIE) remains an important cause of death and disability in newborns. Mild therapeutic hypothermia (TH) is safe and effective; however, there are no tissue biomarkers available at the bedside to select babies for treatment. The aim of this study was to show that it is feasible to study plasma neurofilament light (NfL) levels from newborns and to evaluate their temporal course. Hypothesis: Raised plasma NFL protein levels from newborns who undergo TH after HIE are associated with abnormal MRI outcomes.

Methods

Between February 2014 and January 2016, term newborns with HIE treated with TH for 72 h had plasma samples taken at three time points: (i) after the infant had reached target temperature, (ii) prior to commencing rewarming, and (iii) after completing rewarming. Infants with mild HIE who did not receive TH had a single specimen taken. NfL protein was analyzed using an enzyme-linked immunosorbent assay.

Results

Twenty-six newborns with moderate-severe HIE treated with TH were studied. Half of these had cerebral MRI predictive of an unfavorable outcome. Plasma NfL levels were significantly higher in the TH group with unfavorable outcome (median age 18 h) compared to levels from both the mild HIE group and TH group with favorable outcome (F = 25.83, p < 0.0001). Newborns who had MRIs predictive of unfavorable outcome had significantly higher NfL levels compared to those with favorable outcomes, at all three time points (mixed models, F = 27.63, p < 0.001). A cutoff NfL level >29 pg/mL at 24 h is predictive of an unfavorable outcome [sensitivity 77%, specificity 69%, positive predictive value (PPV) 67%, negative predictive value (NPV) 72%] with increasing predictive value until after rewarming (sensitivity 92%, specificity 92%, PPV 92%, NPV 86%).

Interpretation of research

Plasma NfL protein levels may be a useful biomarker of unfavorable MRI outcomes in newborns with moderate-severe HIE and may assist in selecting newborns for adjunctive neuroprotective interventions. Larger studies with NfL testing at earlier time points are required.

A Single Dose of Docosahexaenoic Acid Increases the Functional Recovery Promoted by Rehabilitation after Cervical Spinal Cord Injury in the Rat

Task-specific rehabilitation has been shown to promote functional recovery after acute spinal cord injury (SCI). Recently, the omega-3 polyunsaturated fatty acid, docosahexaenoic acid (DHA), has been shown to promote neuroplasticity after SCI. Here, we investigated whether the combination of a single bolus of DHA with rehabilitation can enhance the effect of DHA or rehabilitation therapy in adult injured spinal cord. We found enhanced functional improvement with DHA in combination with rehabilitation compared with either treatment alone in a rat cervical lateral hemisection SCI model. This behavioral improvement correlated with a significant sprouting of uninjured corticospinal and serotonergic fibers. We also observed that the greatest increase in the synaptic vesicle protein, synaptophysin, and the synaptic active zone protein, Bassoon, occurred in animals that received both DHA and rehabilitation. In summary, the functional, anatomical, and synaptic plasticity induced by task-specific rehabilitation can be further enhanced by DHA treatment. This study shows the potential beneficial effects of DHA combined with rehabilitation for the treatment of patients with SCI.

In vivo PET imaging of the neuroinflammatory response in rat spinal cord injury using the TSPO tracer [(18)F]GE-180 and effect of docosahexaenoic acid

Purpose

Traumatic spinal cord injury (SCI) is a devastating condition which affects millions of people worldwide causing major disability and substantial socioeconomic burden. There are currently no effective treatments. Modulating the neuroinflammatory (NI) response after SCI has evolved as a major therapeutic strategy. PET can be used to detect the upregulation of the 18-kDa translocator protein (TSPO), a hallmark of activated microglia in the CNS. We investigated whether PET imaging using the novel TSPO tracer [¹⁸F]GE-180 can be used as a clinically relevant biomarker for NI in a contusion SCI rat model, and we present data on the modulation of NI by the lipid docosahexaenoic acid (DHA).

Methods

A total of 22 adult male Wistar rats were subjected to controlled spinal cord contusion at the T10 spinal cord level. Six non-injured and ten T10 laminectomy only (LAM) animals were used as controls. A subset of six SCI animals were treated with a single intravenous dose of 250 nmol/kg DHA (SCI-DHA group) 30 min after injury; a saline-injected group of six animals was used as an injection control. PET and CT imaging was carried out 7 days after injury using the [¹⁸F]GE-180 radiotracer. After imaging, the animals were killed and the spinal cord dissected out for biodistribution and autoradiography studies. In vivo data were correlated with ex vivo immunohistochemistry for TSPO.

Results

In vivo dynamic PET imaging revealed an increase in tracer uptake in the spinal cord of the SCI animals compared with the non-injured and LAM animals from 35 min after injection (P < 0.0001; SCI vs. LAM vs. non-injured). Biodistribution and autoradiography studies confirmed the high affinity and specific [¹⁸F]GE-180 binding in the injured spinal cord compared with the binding in the control groups. Furthermore, they also showed decreased tracer uptake in the T10 SCI area in relation to the non-injured remainder of the spinal cord in the SCI-DHA group compared with the SCI-saline group (P < 0.05), supporting a NI modulatory effect of DHA. Immunohistochemistry showed a high level of TSPO expression (38 %) at the T10 injury site in SCI animals compared with that in the non-injured animals (6 %).

Conclusion

[¹⁸F]GE-180 PET imaging can reveal areas of increased TSPO expression that can be visualized and quantified in vivo after SCI, offering a minimally invasive approach to the monitoring of NI in SCI models and providing a translatable clinical readout for the testing of new therapies.

Electronic supplementary material

The online version of this article (doi:10.1007/s00259-016-3391-8) contains supplementary material, which is available to authorized users.

A study of microRNAs from dried blood spots in newborns after perinatal asphyxia: a simple and feasible biosampling method

BACKGROUND

The potential of microRNAs (miRNAs) as bedside biomarkers in selecting newborns with hypoxic-ischemic encephalopathy (HIE) for neuroprotection has yet to be explored. Commonly, blood-based biomarker tests use plasma or serum which don't allow evaluation of both intracellular and extracellular changes.

METHODS

We describe a technique to extract and compare expression of miRNAs from a single small 6-mm-diameter dried blood spot (DBS) stored at room temperature with those from EDTA-blood, plasma, and urine. Three miRNAs (RNU6B, let7b, and miR-21) were quantified via extraction and quantitative RT-PCR performed from a DBS and compared with levels from EDTA-blood, plasma, and urine. Secondarily, candidate miRNAs let7b, miR-21, miR-29b, miR-124, and miR-155 in DBS were evaluated as potential biomarkers for HIE.

RESULTS

Candidate miRNAs were extractable in all biosamples from newborns, with the highest expression in DBS. There was a good correlation between miRNAs' levels in DBS and EDTA-blood at -80 °C. No significant difference was observed in the miRNA levels between the favorable and unfavorable outcome groups for babies with HIE.

CONCLUSION

DBS may be useful for studying the potential of miRNAs as biomarkers for brain injury.

Modulating inflammatory cell responses to spinal cord injury: all in good time

Spinal cord injury can have a range of debilitating effects, permanently impacting a patient's quality of life. Initially thought to be an immune privileged site, the spinal cord is able to mount a timely and well organized inflammatory response to injury. Intricate immune cell interactions are triggered, typically consisting of a staggered multiphasic immune cell response, which can become deregulated if left unchecked. Although several immunomodulatory compounds have yielded success in experimental rodent spinal cord injury models, their translation to human clinical studies needs further consideration. Because temporal differences between rodent and human inflammatory responses to spinal cord injury do exist, drug delivery timing will be a crucial component in recovery from spinal cord injury. Given too early, immunomodulatory therapies may impede beneficial inflammatory reactions to the injured spinal cord or even miss the opportunity to dampen delayed harmful autoimmune processes. Therefore, this review aims to summarize the temporal inflammatory response to spinal cord injury, as well as detailing specific immune cell functions. By clearly defining the chronological order of inflammatory events after trauma, immunomodulatory drug delivery timing can be better optimized. Further, we compare spinal cord injury-induced inflammatory responses in rodent and human studies, enabling clinicians to consider these differences when initiating clinical trials. Improved understanding of the cellular immune response after spinal cord injury would enhance the efficacy of immunomodulatory agents, enabling combined therapies to be considered.

Multiple roles for NaV1.9 in the activation of visceral afferents by noxious inflammatory, mechanical, and human disease-derived stimuli

Chronic visceral pain affects millions of individuals worldwide and remains poorly understood, with current therapeutic options constrained by gastrointestinal adverse effects. Visceral pain is strongly associated with inflammation and distension of the gut. Here we report that the voltage-gated sodium channel subtype NaV1.9 is expressed in half of gut-projecting rodent dorsal root ganglia sensory neurons. We show that NaV1.9 is required for normal mechanosensation, for direct excitation and for sensitization of mouse colonic afferents by mediators from inflammatory bowel disease tissues, and by noxious inflammatory mediators individually. Excitatory responses to ATP or PGE2 were substantially reduced in NaV1.9(-/-) mice. Deletion of NaV1.9 substantially attenuates excitation and subsequent mechanical hypersensitivity after application of inflammatory soup (IS) (bradykinin, ATP, histamine, PGE2, and 5HT) to visceral nociceptors located in the serosa and mesentery. Responses to mechanical stimulation of mesenteric afferents were also reduced by loss of NaV1.9, and there was a rightward shift in stimulus-response function to ramp colonic distension. By contrast, responses to rapid, high-intensity phasic distension of the colon are initially unaffected; however, run-down of responses to repeat phasic distension were exacerbated in NaV1.9(-/-) afferents. Finally colonic afferent activation by supernatants derived from inflamed human tissue was greatly reduced in NaV1.9(-/-) mice. These results demonstrate that NaV1.9 is required for persistence of responses to intense mechanical stimulation, contributes to inflammatory mechanical hypersensitivity, and is essential for activation by noxious inflammatory mediators, including those from diseased human bowel. These observations indicate that NaV1.9 represents a high-value target for development of visceral analgesics.

The omega-3 fatty acid eicosapentaenoic acid accelerates disease progression in a model of amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a progressive fatal neurodegenerative disease characterised by loss of motor neurons that currently has no cure. Omega-3 polyunsaturated fatty acids, such as eicosapentaenoic acid (EPA), have many health benefits including neuroprotective and myoprotective potential. We tested the hypothesis that a high level of dietary EPA could exert beneficial effects in ALS. The dietary exposure to EPA (300 mg/kg/day) in a well-established mouse model of ALS expressing the G93A superoxide dismutase 1 (SOD1) mutation was initiated at a pre-symptomatic or symptomatic stage, and the disease progression was monitored until the end stage. Daily dietary EPA exposure initiated at the disease onset did not significantly alter disease presentation and progression. In contrast, EPA treatment initiated at the pre-symptomatic stage induced a significantly shorter lifespan. In a separate group of animals sacrificed before the end stage, the tissue analysis showed that the vacuolisation detected in G93A-SOD1 mice was significantly increased by exposure to EPA. Although EPA did not alter motor neurone loss, EPA reversed the significant increase in activated microglia and the astrocytic activation seen in G93A-SOD1 mice. The microglia in the spinal cord of G93A-SOD1 mice treated with EPA showed a significant increase in 4-hydroxy-2-hexenal, a highly toxic aldehydic oxidation product of omega-3 fatty acids. These data show that dietary EPA supplementation in ALS has the potential to worsen the condition and accelerate the disease progression. This suggests that great caution should be exerted when considering dietary omega-3 fatty acid supplements in ALS patients.

Delayed treatment with chondroitinase ABC promotes sensorimotor recovery and plasticity after stroke in aged rats

Stroke is the dominant cause of sensorimotor disability that primarily affects the elderly. We now show that neuroplasticity and functional recovery after stroke is constrained by inhibitory chondroitin sulphates. In two blinded, randomized preclinical trials, degradation of chondroitin sulphate using chondroitinase ABC reactivated neuroplasticity and promoted sensorimotor recovery after stroke in elderly rats. Three days after stroke, chondroitinase ABC was microinjected into the cervical spinal cord to induce localized plasticity of forelimb sensorimotor spinal circuitry. Chondroitinase ABC effectively removed chondroitin sulphate from the extracellular matrix and perineuronal nets. Three different tests of sensorimotor function showed that chondroitinase ABC promoted recovery of forelimb function. Anterograde and retrograde tracing showed that chondroitinase ABC also induced sprouting of the contralesional corticospinal tract in the aged treated hemicord. Chondroitinase ABC did not neuroprotect the peri-infarct region. We show for the first time delayed chondroitinase ABC treatment promotes neuroanatomical and functional recovery after focal ischaemic stroke in an elderly nervous system.

Spinal cord trauma and the molecular point of no return

A mechanical trauma to the spinal cord can be followed by the development of irreversible and progressive neurodegeneration, as opposed to a temporary or partially reversible neurological damage. An increasing body of experimental and clinical evidence from humans and animal models indicates that spinal cord injury may set in motion the development of disabling and at times fatal neuromuscular disorders, whose occurrence is not normally associated with any major environmental event. This outcome appears to be dependent on the co-occurrence of a particular form of mechanical stress and of a genetically-determined vulnerability. This increased vulnerability to spinal cord injury may depend on a change of the nature and of the timing of activation of a number of neuroprotective and neurodestructive molecular signals in the injured cord. Among the main determinants, we could mention an altered homeostasis of lipids and neurofilaments, an earlier inflammatory response and the failure of the damaged tissue to rein in oxidative damage and apoptotic cell death. These changes could force injured tissue beyond a point of no return and precipitate an irreversible neurodegenerative process. A better knowledge of the molecular signals activated in a state of increased vulnerability to trauma can inform future treatment strategies and the prediction of the neurological outcome after spinal cord injury.

Specific involvement of atypical PKCζ/PKMζ in spinal persistent nociceptive processing following peripheral inflammation in rat

Background

Central sensitization requires the activation of various intracellular signalling pathways within spinal dorsal horn neurons, leading to a lowering of activation threshold and enhanced responsiveness of these cells. Such plasticity contributes to the manifestation of chronic pain states and displays a number of features of long-term potentiation (LTP), a ubiquitous neuronal mechanism of increased synaptic strength. Here we describe the role of a novel pathway involving atypical PKCζ/PKMζ in persistent spinal nociceptive processing, previously implicated in the maintenance of late-phase LTP.

Results

Using both behavioral tests and in vivo electrophysiology in rats, we show that inhibition of this pathway, via spinal delivery of a myristoylated protein kinase C-ζ pseudo-substrate inhibitor, reduces both pain-related behaviors and the activity of deep dorsal horn wide dynamic range neurons (WDRs) following formalin administration. In addition, Complete Freund's Adjuvant (CFA)-induced mechanical and thermal hypersensitivity was also reduced by inhibition of PKCζ/PKMζ activity. Importantly, this inhibition did not affect acute pain or locomotor behavior in normal rats and interestingly, did not inhibited mechanical allodynia and hyperalgesia in neuropathic rats. Pain-related behaviors in both inflammatory models coincided with increased phosphorylation of PKCζ/PKMζ in dorsal horn neurons, specifically PKMζ phosphorylation in formalin rats. Finally, inhibition of PKCζ/PKMζ activity decreased the expression of Fos in response to formalin and CFA in both superficial and deep laminae of the dorsal horn.

Conclusions

These results suggest that PKCζ, especially PKMζ isoform, is a significant factor involved in spinal persistent nociceptive processing, specifically, the manifestation of chronic pain states following peripheral inflammation.

The human G93A-SOD1 mutation in a pre-symptomatic rat model of amyotrophic lateral sclerosis increases the vulnerability to a mild spinal cord compression

Background

Traumatic injuries can undermine neurological functions and act as risk factors for the development of irreversible and fatal neurodegenerative disorders like amyotrophic lateral sclerosis (ALS). In this study, we have investigated how a mutation of the superoxide dismutase 1 (SOD1) gene, linked to the development of ALS, modifies the acute response to a gentle mechanical compression of the spinal cord. In a 7-day post-injury time period, we have performed a comparative ontological analysis of the gene expression profiles of injured spinal cords obtained from pre-symptomatic rats over-expressing the G93A-SOD1 gene mutation and from wild type (WT) littermates.

Results

The steady post-injury functional recovery observed in WT rats was accompanied by the early activation at the epicenter of injury of several growth-promoting signals and by the down-regulation of intermediate neurofilaments and of genes involved in the regulation of ion currents at the 7 day post-injury time point. The poor functional recovery observed in G93A-SOD1 transgenic animals was accompanied by the induction of fewer pro-survival signals, by an early activation of inflammatory markers, of several pro-apoptotic genes involved in cytochrome-C release and by the persistent up-regulation of the heavy neurofilament subunits and of genes involved in membrane excitability. These molecular changes occurred along with a pronounced atrophy of spinal cord motor neurones in the G93A-SOD1 rats compared to WT littermates after compression injury.

Conclusions

In an experimental paradigm of mild mechanical trauma which causes no major tissue damage, the G93A-SOD1 gene mutation alters the balance between pro-apoptotic and pro-survival molecular signals in the spinal cord tissue from the pre-symptomatic rat, leading to a premature activation of molecular pathways implicated in the natural development of ALS.

Systemic blockade of P2X3 and P2X2/3 receptors attenuates bone cancer pain behaviour in rats

Pain remains an area of considerable unmet clinical need, and this is particularly true of pain associated with bone metastases, in part because existing analgesic drugs show only limited efficacy in many patients and in part because of the adverse side effects associated with these agents. An important issue is that the nature and roles of the algogens produced in bone that drive pain-signalling systems remain unknown. Here, we tested the hypothesis that adenosine triphosphate is one such key mediator through actions on P2X3 and P2X2/3 receptors, which are expressed selectively on primary afferent nocioceptors, including those innervating the bone. Using a well-established rat model of bone cancer pain, AF-353, a recently described potent and selective P2X3 and P2X2/3 receptor antagonist, was administered orally to rats and found to produce highly significant prevention and reversal of bone cancer pain behaviour. This attenuation occurred without apparent modification of the disease, since bone destruction induced by rat MRMT-1 carcinoma cells was not significantly altered by AF-353. Using in vivo electrophysiology, evidence for a central site of action was provided by dose-dependent reductions in electrical, mechanical and thermal stimuli-evoked dorsal horn neuronal hyperexcitability following direct AF-353 administration onto the spinal cord of bone cancer animals. A peripheral site of action was also suggested by studies on the extracellular release of adenosine triphosphate from MRMT-1 carcinoma cells. Moreover, elevated phosphorylated-extracellular signal-regulated kinase expression in dorsal root ganglion neurons, induced by co-cultured MRMT-1 carcinoma cells, was significantly reduced in the presence of AF-353. These data suggest that blockade of P2X3 and P2X2/3 receptors on both the peripheral and central terminals of nocioceptors contributes to analgesic efficacy in a model of bone cancer pain. Thus, systemic P2X3 and P2X2/3 receptor antagonists with central nervous system penetration may offer a promising therapeutic tool in treating bone cancer pain.

Cortical overexpression of neuronal calcium sensor-1 induces functional plasticity in spinal cord following unilateral pyramidal tract injury in rat

Overexpression of neuronal calcium sensor 1 in cortical neurons can help restore axonal plasticity and regeneration following axonal injury in adult rats, and can also improve behavioral function.

Following trauma of the adult brain or spinal cord the injured axons of central neurons fail to regenerate or if intact display only limited anatomical plasticity through sprouting. Adult cortical neurons forming the corticospinal tract (CST) normally have low levels of the neuronal calcium sensor-1 (NCS1) protein. In primary cultured adult cortical neurons, the lentivector-induced overexpression of NCS1 induces neurite sprouting associated with increased phospho-Akt levels. When the PI3K/Akt signalling pathway was pharmacologically inhibited the NCS1-induced neurite sprouting was abolished. The overexpression of NCS1 in uninjured corticospinal neurons exhibited axonal sprouting across the midline into the CST-denervated side of the spinal cord following unilateral pyramidotomy. Improved forelimb function was demonstrated behaviourally and electrophysiologically. In injured corticospinal neurons, overexpression of NCS1 induced axonal sprouting and regeneration and also neuroprotection. These findings demonstrate that increasing the levels of intracellular NCS1 in injured and uninjured central neurons enhances their intrinsic anatomical plasticity within the injured adult central nervous system.

Following trauma to the central nervous system (brain or spinal cord), neurons show very little capacity to re-grow their axons, which can lead to a permanent loss of function in those regions. In this study, we show that this failure of axon re-growth is associated with low intracellular levels of a small molecule called neuronal calcium sensor-1 (NCS1). We modified a non-replicating virus in two ways so as to increase the level of NCS1 in neurons while simultaneously labelling them with a green fluorescent protein, which allowed us to track neuronal growth. Using this virus to increase the level of NCS1 in a particular group of neurons that communicate between the brain and spinal cord, we showed that new axonal growth occurred in the spinal cord with or without injury to the neurons. Electrophysiological assessments demonstrated that these new processes formed functional connections in the spinal cord, and behavioural experiments revealed that this recovery also helped the animals move their limbs more effectively. Furthermore, an increase in NCS1 protected these neurons, such that fewer of them died after the injury. These findings demonstrate that increasing the intracellular levels of NCS1 in neurons can aid in the recovery from central nervous system injury, and can help improve behavioural function.

Activation transcription factor-3 activation and the development of spinal cord degeneration in a rat model of amyotrophic lateral sclerosis

It has been reported that an early activation of glial fibrillary acid protein (GFAP) in astroglial cells occurs simultaneously in peripheral nerves and spinal cord from the G93A SOD1 mouse model of amyotrophic lateral sclerosis (ALS), an invariably fatal neurodegenerative disorder. In ALS, the contribute to the pathological process of different cell types varies according to the disease stage, with a florid immune response in spinal cord at end stage disease. In this study, we have mapped in different anatomical sites the process of disease-induced functional perturbation from a pre-symptomatic stage using a marker of cellular distress expressed in neurons and glial cells, the activating transcription factor 3 (ATF-3), and applied large-scale gene expression analysis to define the pattern or transcriptional changes occurring in spinal cord from the G93A SOD1 rat model of ALS in parallel with ATF-3 neuronal activation. From the disease onset onward, transgenic lumbar spinal cord displayed ATF-3 transcriptional regulation and motor cells immunostaining in association with the over-expression of genes promoting cell growth, the functional integrity of cell organelles and involved in the modulation of immune responses. While spinal cord from the pre-symptomatic rat showed no detectable ATF-3 transcriptional regulation, ATF-3 activation was appreciated in large size neurofilament-rich, small size non-peptidergic and parvalbumin-positive neurons within the dorsal root ganglia (DRG), and in ventral roots Schwann cells alongside macrophages infiltration. This pattern of peripheral ATF-3 activation remained detectable throughout the disease process. In the G93A SOD1 rat model of ALS, signs of roots and nerves subtle distress preceded overt clinical-pathological changes, involving both glial cells and neurons that function as receptors of peripheral sensory stimuli from the muscle. In addition, factors previously described to be linked to ATF-3 activation under various experimental conditions of stress, become switched on in spinal cord from the end-stage transgenic rat model of ALS.

Expression of the regeneration-associated protein SPRR1A in primary sensory neurons and spinal cord of the adult mouse following peripheral and central injury

Small proline-rich repeat protein 1A (SPRR1A) is expressed in dorsal root ganglion (DRG) neurons following peripheral nerve injury but it is not known whether SPRR1A is differentially expressed following injury to peripheral versus central DRG projections and a detailed characterization of expression in sensory neuron subpopulations and spinal cord has not been performed. Here we use immunocytochemical techniques to characterize SPRR1A expression following sciatic nerve, dorsal root, and dorsal column injury in adult mice. SPRR1A was not detected in naïve spinal cord, DRG, or peripheral nerves and there was minimal expression following injury to the centrally projecting branches of DRG neurons. However, following peripheral (sciatic) nerve injury, intense SPRR1A immunoreactivity was observed in the dorsal horn and motoneurons of the spinal cord, in L4/5 DRG neurons, and in the injured nerve. A time-course study comparing expression following sciatic nerve crush and transection revealed maximum SPRR1A levels at day 7 in both models. However, while SPRR1A was downregulated to baseline by 30 days postlesion following crush injury, it remained elevated 30 days after transection. Cell-size and double-labeling studies revealed that SPRR1A was expressed by DRG cells of all sizes and colocalized with classical markers of DRG subpopulations and their primary afferent terminals. High coexpression of SPRR1A with activating transcription factor-3 and growth-associated protein-43 was observed, indicating that it is expressed by injured and regenerating neurons. This study supports the hypothesis that SPRR1A is a regeneration-associated gene and that SPRR1A provides a valuable marker to assess the regenerative potential of injured neurons.

Characterisation of ultraviolet-B-induced inflammation as a model of hyperalgesia in the rat

In humans, the acute inflammatory reaction caused by ultraviolet (UV) radiation is well studied and the sensory changes that are found have been used as a model of cutaneous hyperalgesia. Similar paradigms are now emerging as rodent models of inflammatory pain. Using a narrowband UVB source, we irradiated the plantar surface of rat hind paws. This produced the classical feature of inflammation, erythema, and a significant dose-dependent reduction in both thermal and mechanical paw withdrawal thresholds. These sensory changes peaked 48h after irradiation. At this time there is a graded facilitation of noxious heat evoked (but not basal) c-fos-like immunoreactivity in the L4/5 segments of the spinal cord. We also studied the effects of established analgesic compounds on the UVB-induced hyperalgesia. Systemic as well as topical application of ibuprofen significantly reduced both thermal and mechanical hyperalgesia. Systemic morphine produced a dose-dependent and naloxone sensitive reversal of sensory changes. Similarly, the peripherally restricted opioid loperamide also had a dose-dependent anti-hyperalgesic effect, again reversed by naloxone methiodide. Sequestration of NGF, starting at the time of UVB irradiation, significantly reduced sensory changes. We conclude that UVB inflammation produces a dose-dependent hyperalgesic state sensitive to established analgesics. This suggests that UVB inflammation in the rat may represent a useful translational tool in the study of pain and the testing of analgesic agents.

Inhibition of spinal microglial cathepsin S for the reversal of neuropathic pain

A recent major conceptual advance has been the recognition of the importance of immune system-neuronal interactions in the modulation of brain function, one example of which is spinal pain processing in neuropathic states. Here, we report that in peripheral nerve-injured rats, the lysosomal cysteine protease cathepsin S (CatS) is critical for the maintenance of neuropathic pain and spinal microglia activation. After injury, CatS was exclusively expressed by activated microglia in the ipsilateral dorsal horn, where expression peaked at day 7, remaining high on day 14. Intrathecal delivery of an irreversible CatS inhibitor, morpholinurea-leucine-homophenylalanine-vinyl phenyl sulfone (LHVS), was antihyperalgesic and antiallodynic in neuropathic rats and attenuated spinal microglia activation. Consistent with a pronociceptive role of endogenous CatS, spinal intrathecal delivery of rat recombinant CatS (rrCatS) induced hyperalgesia and allodynia in naïve rats and activated p38 mitogen-activated protein kinase (MAPK) in spinal cord microglia. A bioinformatics approach revealed that the transmembrane chemokine fractalkine (FKN) is a potential substrate for CatS cleavage. We show that rrCatS incubation reduced the levels of cell-associated FKN in cultured sensory neurons and that a neutralizing antibody against FKN prevented both FKN- and CatS-induced allodynia, hyperalgesia, and p38 MAPK activation. Furthermore, rrCatS induced allodynia in wild-type but not CX3CR1-knockout mice. We suggest that under conditions of increased nociception, microglial CatS is responsible for the liberation of neuronal FKN, which stimulates p38 MAPK phosphorylation in microglia, thereby activating neurons via the release of pronociceptive mediators.

Lentiviral vector expressing retinoic acid receptor beta2 promotes recovery of function after corticospinal tract injury in the adult rat spinal cord

Spinal cord injury often results in permanent and devastating neurological deficits and disability. This is due to the limited regenerative capacity of neurones in the central nervous system (CNS). We recently demonstrated that a transcription factor retinoic acid receptor beta2 (RARbeta2) promoted axonal regeneration in adult sensory neurones located peripherally. However, it is not known if RARbeta2 can promote axonal regeneration in cortical neurones of the CNS. Here, we demonstrate that delivery of RARbeta2 via a lentiviral vector to adult dissociated cortical neurones significantly enhances neurite outgrowth on adult cortical cryosections, which normally provide an unfavourable substrate for growth. We also show that lentiviral-mediated transduction of corticospinal neurones resulted in robust transgene expression in layer V corticospinal neurones and their axonal projections in the corticospinal tract (CST) of the spinal cord. Expression of RARbeta2 in these neurones enhanced regeneration of the descending CST fibres after injury to these axons in the mid-cervical spinal cord. Furthermore, we observed functional recovery in sensory and locomotor behavioural tests in RARbeta2-treated animals. These results suggest that a direct and selective delivery of RARbeta2 to the corticospinal neurones promotes long-distance functional regeneration of axons in the spinal cord and may thus offer new therapeutic gene strategy for the treatment of human spinal cord injuries.

Interactions between retinoic acid, nerve growth factor and sonic hedgehog signalling pathways in neurite outgrowth

Many studies have shown a role of retinoid signalling in neurite outgrowth in vitro, and that the retinoic acid receptor (RAR) beta2 is critical for this process. We show here that RARbeta2 is expressed predominantly in dorsal root ganglia (DRG) neuronal subtypes that express neurofilament (NF) 200 and calcitonin gene-related peptide (CGRP), and that these neurons extend neurites in response to RA. We demonstrate that retinoid signalling has a role in neurite outgrowth in vivo, by showing that in a peripheral nerve crush model there is less neurite outgrowth from RARbeta null DRG compared to wild-type. We identify sonic hedgehog (Shh) as a downstream target of the RARbeta2 signalling pathway as it is expressed in the injured DRG of wild-type but not RARbeta null mice. This regulation is direct as when RARbeta2 is overexpressed in adult motoneurons Shh is induced in them. Finally we show that Shh alone cannot induce neurite outgrowth but potentiates RARbeta2 signalling in this process.

The impact of lesion length on angiographic restenosis after vertebral artery origin stenting

OBJECTIVE

To evaluate the effect of lesion length on in-stent restenosis (ISR) of vertebral artery (VA) origin stenting.

METHODS

We retrospectively analyzed the medical and radiological records of patients receiving VA origin stenting from March 1999 to June 2005. They were subdivided according to lesion length. ISR was defined as >50% diameter narrowing in stent.

RESULTS

Eighty symptomatic patients (64 male, mean age 72 years) with 90 lesions treated with balloon expandable tubular coronary stents were enrolled. There were 34 patients with 38 short lesions (length<or=5 mm, group 1), 37 patients with 42 medium lesions (length>5 mm, <10 mm, group 2) and 9 patients with 10 long lesions (length>or=10 mm, group 3). Eighty seven bare-metal stents and 3 drug-eluting stents were implanted. Repeat angiography was done in 40 lesions (44%) at 11.7+/-9.6 months. The ISR rate in group 1, 2, 3 is 21%, 29%, and 50% (p=0.486). Multivariable Cox regression analysis showed lesion length was the only significant independent predictor of ISR (hazard ratio: 1.19, p=0.039).

CONCLUSION

ISR of VA origin stenting is common. Lesion length is an important predictor of ISR in VA origin stenting.

Retinoic acid receptor β2 promotes functional regeneration of sensory axons in the spinal cord

The embryonic CNS readily undergoes regeneration, unlike the adult CNS, which has limited axonal repair after injury. Here we tested the hypothesis that retinoic acid receptor beta2 (RARbeta2), critical in development for neuronal growth, may enable adult neurons to grow in an inhibitory environment. Overexpression of RARbeta2 in adult rat dorsal root ganglion cultures increased intracellular levels of cyclic AMP and stimulated neurite outgrowth. Stable RARbeta2 expression in DRG neurons in vitro and in vivo enabled their axons to regenerate across the inhibitory dorsal root entry zone and project into the gray matter of the spinal cord. The regenerated neurons enhanced second-order neuronal activity in the spinal cord, and RARbeta2-treated rats showed highly significant improvement in sensorimotor tasks. These findings show that RARbeta2 induces axonal regeneration programs within injured neurons and may thus offer new therapeutic opportunities for CNS regeneration.

Assessing behavioural function following a pyramidotomy lesion of the corticospinal tract in adult mice

We have developed a pyramidotomy model in mice to lesion the corticospinal tract at the level of the brainstem pyramidal tract, and evaluated the resultant impairments in motor function in a series of behavioural tests. Adult C57BL/6 mice received a unilateral pyramidotomy and a control group of mice underwent sham surgery. We studied the effects of this lesion on forepaw function using five behavioural paradigms, some of which have been widely used in rat studies but have not been fully explored in mice. The tests used were: a rearing test, which assesses forepaw use for weight support during spontaneous vertical exploration of a cylinder; a grid walking test, which assesses the ability to accurately place the forepaws during exploration of an elevated grid; a tape-removal test, which measures both sensory and motor function of the forepaw; a CatWalk automated gait analysis, which provides a number of quantitative measures including stride length and stride width during locomotion; and a staircase reaching task, which assesses skilled independent forepaw use. All tests revealed lesion effects on forepaw function with the tape removal, grid walking, rearing and CatWalk tests demonstrating robust effects throughout the testing period. The development of a pyramidotomy lesion model in mice, together with behavioural tests which can reliably measure functional impairments, will provide a valuable tool for assessing therapeutic strategies to promote regeneration and plasticity.

Intracranial dural arteriovenous fistulas with or without cerebral sinus thrombosis: analysis of 69 patients

OBJECTIVES

To compare the characteristics of dural arteriovenous fistulas (AVFs) with or without cerebral sinus thrombosis (CST), and to analyse the determinants of aggressive manifestations in patients with dural AVF.

METHODS

We investigated 69 patients aged 51.4 (SD 15) years who were diagnosed as having dural AVF. According to the location of the lesion and venous drainage pattern, dural AVF was classified into three sites (cavernous sinus, large sinus, and other) and five types (by Cognard's method). Aggressive manifestations of dural AVF were defined as intracranial haemorrhage, venous infarction, seizure, altered mental status, and intracranial hypertension. The diagnosis of CST was based on cerebral angiography. Logistic regression methods were used to analyse the determinants of aggressive manifestation in patients with dural AVF.

RESULTS

CST was found in 39% of the patients with dural AVF. It was located at almost either the sinus around the dural AVF or the downstream venous flow pathways of the dural AVF. There was no significant difference with regard to sex, location, or type of dural AVF between patients with dural AVF with and without CST. The location "other sinuses" and the type of dural AVF "IIb/IIa+b/III/IV/V" were significantly related to aggressive manifestations of dural AVF (odds ratio 19 (p = 0.001) and 5.63 (p = 0.033), respectively). Presence of CST in patients with dural AVF had an odds ratio of 4.25 (p = 0.12) for development of aggressive manifestations.

CONCLUSIONS

CST affects two fifths of patients with dural AVF. The location and type of dural AVF are major determinants of aggressive manifestations in patients with dural AVF.

Release of BDNF and GABA in the dorsal horn of neuropathic rats

Damage to peripheral nerves is associated with changes in excitability and/or phenotype of primary afferent neurons as well as increased neuronal excitability (central sensitization) and reduced inhibitory tone in the dorsal horn. For instance, in dorsal root ganglia (DRG) brain derived neurotrophic factor (BDNF) is down-regulated in small cells whilst de novo expressed in large diameter cells. In the dorsal horn, GABA content is decreased. In this study, in a dorsal horn, 'with dorsal roots attached' preparation obtained from spinal nerve lesioned Wistar rats, stimulation of ipsilateral dorsal roots at either A fibre or A + C fibre strength did not evoke release of BDNF. In separate experiments, activity-induced release of GABA in the isolated dorsal horn of neuropathic rats was significantly reduced compared to release in sham operated rats. GABA release could be significantly restored following topical application of BDNF through the dorsal horn preparation. Finally, neuropathic rats developed thermal and mechanical hypersensitivity and thermal hyperalgesia was reduced by intrathecal injection of BDNF. We concluded that BDNF-induced release of GABA could be a mechanism to explain the antinociceptive action of intrathecal BDNF in neuropathic animals. Furthermore, reduced availability of sensory neuron-derived BDNF might contribute to the reduced GABAergic tone in the dorsal horn of neuropathic rats.

Long-term clinical outcome of spontaneous carotid cavernous sinus fistulae supplied by dural branches of the internal carotid artery

We report the long-term clinical outcome of spontaneous carotid cavernous sinus fistulae (CCF) originally supplied by branches arising from the internal carotid artery (Barrow's type B), or type-D lesion that became type B after particulate embolization. A total of 55 patients was included in this study. Their angiography revealed that cortical drainage was absent, and that the arteries supplying the fistulae originated in the dural branches of the internal carotid artery. Thirty-two patients had type-D lesions, which became type-B lesions after obliteration of the external carotid supply by endovascular treatment. The other 23 patients had type-B lesions documented by angiography, and had no embolization. The follow-up period ranged from 8 to 144.5 months. Clinical cure was achieved in 39 patients (70.9%), improvement in eight patients (14.5%), the lesion remained stable in four patients (7.3%), and was aggravated in four patients (7.3%). The number of drainage veins is the only radiographic factor that could predict the outcome. Those patients with single draining veins had a better chance of complete remission. The outcome between the group with original type D lesions after embolization and the group with original type B revealed no statistically significant difference. The time-course to complete cure was significantly shorter in the group with embolization of the external carotid supply. In the four patients whose symptoms were aggravated, embolization was performed, and the result was excellent. The clinical outcome of type-B CCF, or type D converted to type B, is good. Previous external carotid artery embolization can significantly shorten the time to complete cure. Aggressive treatment should be reserved for those who have aggravated symptoms.

Factor structure and explanatory variables of the Mini-Mental State Examination (MMSE) for elderly persons in Taiwan

BACKGROUND AND PURPOSE

The Mini-Mental State Examination (MMSE) is commonly used in studies and clinical assessment of cognitive functioning. The purpose of this study was to examine the factor structure and variables explaining the scores of the MMSE in elderly persons in Taiwan, in order to provide a reference for instrument selection and data collection for clinicians and researchers.

METHODS

Secondary data from an epidemiologic study that included 1,442 randomly selected subjects aged 64 to 98 with an average age of 72.6 years were used. Males comprised 57.1% of the sample, and females 42.9%. Exploratory and confirmatory factor analysis and covariance structure modeling were used to analyze the data.

RESULTS

In the cross validation of the covariance structure modeling, 50.1% of the variance in simple processing, 86.9% in complex processing, and 66.9% in memory/attention were explained. Better education background predicted better score in complex processing ability (path coefficient = .860). Greater independence in self-care ability predicted better scores in simple processing (path coefficient = -.716) and memory/attention (path coefficient = -.811).

CONCLUSION

The results of this study indicate that items in the MMSE measuring complex processing ability including writing, reading and obeying, and copy design are seriously biased by educational background, and that the remaining items are better indicators of the subject's cognitive functioning for elderly persons in Taiwan. In our model, self-care ability was strongly related to cognitive functioning as measured by the MMSE, especially for items in the factors of simple processing (registration, naming, repetition, and commanding) and attention/memory (orientation to place and time, attention, and recall).

Correlations between peripheral differential leukocyte counts and carotid atherosclerosis in non-smokers

Substantial evidence clearly indicates the immuno-inflammatory nature of atherosclerosis and the important roles of monocytes and other leukocytes in atherogenesis. The relationship between atherosclerosis and the peripheral monocyte count, however, has been equivocal and uncertain so far. One possible reason may be an opposing effect of different major risk factors of atherosclerosis on the monocyte count, e.g. smoking increases the monocyte count while hypercholesterolemia is accompanied by a lower monocyte count. Since smoking is well shown to increase leukocyte counts prominently in weeks, our study included only non-smokers who participated in a health check program at our hospital from 1996 to 1998 and had received a carotid duplex study with extra payment. Our results revealed the followings: In male non-smokers (n=571), the presence of carotid atherosclerosis was associated with significant increases in the counts of all leukocyte, neutrophil, and monocyte (P<0.005,<0.001 and <0.05, respectively), and, after adjustments for age and body mass index, there were significant positive links between these three leukocyte counts and the severity of carotid atherosclerosis, judged by either the sum score of all carotid plaques or the score of the most severe carotid plaque. On the contrary, in female non-smokers (n=614), there was no significant link between differential leukocyte counts and either the presence or severity of carotid atherosclerosis. These results are compatible with recently recognized sex differences in the mechanism and pathophysiology of atherosclerosis, and together with relevant results in the literature, suggest that monocytes and neutrophils are the main types of leukocytes involved in atherosclerosis.