What has inflammation to do with traumatic brain injury?

Microglial histone deacetylase 2 is dispensable for functional and histological outcomes in a mouse model of traumatic brain injury

The Class-I histone deacetylases (HDACs) mediate microglial inflammation and neurological dysfunction after traumatic brain injury (TBI). However, whether the individual Class-I HDACs play an indispensable role in TBI pathogenesis remains elusive. HDAC2 has been shown to upregulate pro-inflammatory genes in myeloid cells under brain injuries such as intracerebral hemorrhage, thereby worsening outcomes. Thus, we hypothesized that HDAC2 drives microglia toward a pro-inflammatory neurotoxic phenotype in a murine model of controlled cortical impact (CCI). Our results revealed that HDAC2 expression was highly induced in CD16/CD32+ pro-inflammatory microglia 3 and 7d after TBI. Surprisingly, microglia-targeted HDAC2 knockout (HDAC2 miKO) mice failed to demonstrate a beneficial phenotype after CCI/TBI compared to their wild-type (WT) littermates. HDAC2 miKO mice exhibited comparable levels of grey and white matter injury, efferocytosis, and sensorimotor and cognitive deficits after CCI/TBI as WT mice. RNA sequencing of isolated microglia 3d after CCI/TBI indicated the elevation of a panel of pro-inflammatory cytokines/chemokines in HDAC2 miKO mice over WT mice, and flow cytometry showed further elevated brain infiltration of neutrophils and B cells in HDAC2 miKO mice. Together, this study does not support a detrimental role for HDAC2 in microglial responses after TBI and calls for investigation into alternative mechanisms.

Neonatal microglia transplantation at early stage but not late stage after traumatic brain injury shows protective effects in mice

The transplantation of neonatal microglia suppresses neuroinflammation caused by traumatic brain injury (TBI). This research aimed to explore the optimal time point of neonatal microglia transplantation for the best effect on the improvement of long-term cognitive function and inflammatory response in mouse models. qPCR and immunoblotting showed that the level of Iba1 gradually increased to the highest on day 7 and then gradually declined in TBI mice. Furthermore, it was observed that the level of CD86 and TNF-α increased to the highest after 7 days and subsequently was maintained until day 21, whereas the level of CD206 and IL-10 increased to the highest after 24 h and subsequently decreased until day 21 by qPCR and enzyme-linked immunosorbent assay. Afterward, it was shown that the neonatal microglia transplantation within 1 h significantly attenuated anxiety-like behavior and improved cognitive impairments in TBI mice. Mechanism exploration showed that the neonatal microglia could significantly decrease the level of cleaved caspase-3, M1/M2 polarization, and inflammatory cytokine (TNF-α) while increasing the level of anti-inflammatory factor IL-10 in TBI mice after transplantation within 1 h. Here, our findings demonstrated that neonatal microglia transplantation within 1 h significantly attenuated anxiety-like behavior and cognitive impairments caused by TBI.NEW & NOTEWORTHY The study demonstrated that neonatal microglia transplantation within 1 h significantly inhibited the pathogenesis of traumatic brain injury (TBI) in mouse models through inhibition of M1 polarization and promotion of M2 polarization.

Upregulation of multiple toll-like receptors in ferret brain after blast exposure: potential targets for treatment

Although blast-induced traumatic brain injury (bTBI) has been designated as the signature injury of recent combat operations, its precise pathological mechanism(s) has not been identified thus far. Prior preclinical studies on bTBI demonstrated acute neuroinflammatory cascades which are known to be contributing to neurodegeneration. Danger-associated chemical patterns are released from the injured cells, which activate non-specific pattern recognition receptors, such as toll-like receptors (TLRs) leading to increased expression of inflammatory genes and release of cytokines. Upregulation of specific TLRs in the brain has been described as a mechanism of injury in diverse brain injury models unrelated to blast exposure. However, the expression profile of various TLRs in bTBI has not been investigated thus far. Hence, we have evaluated the expression of transcripts for TLR1-TLR10 in the brain of a gyrencephalic animal model of bTBI. We exposed ferrets to tightly coupled repeated blasts and determined the differential expression of TLRs (TLR1-10) by quantitative RT-PCR in multiple brain regions at 4 hr, 24 hr, 7 days and 28 days post-blast injury. The results obtained indicate that multiple TLRs are upregulated in the brain at 4 hr, 24 hr, 7 days and 28 days post-blast. Specifically, upregulation of TLR2, TLR4 and TLR9 was noted in different brain regions, suggesting that multiple TLRs might play a role in the pathophysiology of bTBI and that drugs that can inhibit multiple TLRs might have enhanced efficacy to attenuate brain damage and thereby improve bTBI outcome. Taken together, these results suggest that several TLRs are upregulated in the brain after bTBI and participate in the inflammatory response and thereby provide new insights into the disease pathogenesis. Therefore, inhibition of multiple TLRs, including TLR2, 4 and 9, simultaneously might be a potential therapeutic strategy for the treatment of bTBI.

Brain Trauma and the Secondary Cascade in Humans: Review of the Potential Role of Vitamins in Reparative Processes and Functional Outcome

An estimated sixty-nine million people sustain a traumatic brain injury each year. Trauma to the brain causes the primary insult and initiates a secondary biochemical cascade as part of the immune and reparative response to injury. The secondary cascade, although a normal physiological response, may also contribute to ongoing neuroinflammation, oxidative stress and axonal injury, continuing in some cases years after the initial insult. In this review, we explain some of the biochemical mechanisms of the secondary cascade and their potential deleterious effects on healthy neurons including secondary cell death. The second part of the review focuses on the role of micronutrients to neural mechanisms and their potential reparative effects with regards to the secondary cascade after brain injury. The biochemical response to injury, hypermetabolism and excessive renal clearance of nutrients after injury increases the demand for most vitamins. Currently, most research in the area has shown positive outcomes of vitamin supplementation after brain injury, although predominantly in animal (murine) models. There is a pressing need for more research in this area with human participants because vitamin supplementation post-trauma is a potential cost-effective adjunct to other clinical and therapeutic treatments. Importantly, traumatic brain injury should be considered a lifelong process and better evaluated across the lifespan of individuals who experience brain injury.

Pathophysiology and Neuroimmune Interactions Underlying Parkinson's Disease and Traumatic Brain Injury

Parkinson's disease (PD) is a progressive neurodegenerative disorder clinically defined by motor instability, bradykinesia, and resting tremors. The clinical symptomatology is seen alongside pathologic changes, most notably the loss of dopaminergic neurons in the substantia nigra pars compacta (SNpc) and the accumulation of α-synuclein and neuromelanin aggregates throughout numerous neural circuits. Traumatic brain injury (TBI) has been implicated as a risk factor for developing various neurodegenerative diseases, with the most compelling argument for the development of PD. Dopaminergic abnormalities, the accumulation of α-synuclein, and disruptions in neural homeostatic mechanisms, including but not limited to the release of pro-inflammatory mediators and the production of reactive oxygen species (ROS), are all present following TBI and are closely related to the pathologic changes seen in PD. Neuronal iron accumulation is discernable in degenerative and injured brain states, as is aquaporin-4 (APQ4). APQ4 is an essential mediator of synaptic plasticity in PD and regulates edematous states in the brain after TBI. Whether the cellular and parenchymal changes seen post-TBI directly cause neurodegenerative diseases such as PD is a point of considerable interest and debate; this review explores the vast array of neuroimmunological interactions and subsequent analogous changes that occur in TBI and PD. There is significant interest in exploring the validity of the relationship between TBI and PD, which is a focus of this review.

Vascular Effects on Cerebrovascular Permeability and Neurodegeneration

Neurons and glial cells in the brain are protected by the blood brain barrier (BBB). The local regulation of blood flow is determined by neurons and signal conducting cells called astrocytes. Although alterations in neurons and glial cells affect the function of neurons, the majority of effects are coming from other cells and organs of the body. Although it seems obvious that effects beginning in brain vasculature would play an important role in the development of various neuroinflammatory and neurodegenerative pathologies, significant interest has only been directed to the possible mechanisms involved in the development of vascular cognitive impairment and dementia (VCID) for the last decade. Presently, the National Institute of Neurological Disorders and Stroke applies considerable attention toward research related to VCID and vascular impairments during Alzheimer's disease. Thus, any changes in cerebral vessels, such as in blood flow, thrombogenesis, permeability, or others, which affect the proper vasculo-neuronal connection and interaction and result in neuronal degeneration that leads to memory decline should be considered as a subject of investigation under the VCID category. Out of several vascular effects that can trigger neurodegeneration, changes in cerebrovascular permeability seem to result in the most devastating effects. The present review emphasizes the importance of changes in the BBB and possible mechanisms primarily involving fibrinogen in the development and/or progression of neuroinflammatory and neurodegenerative diseases resulting in memory decline.

Prolonged and intense neuroinflammation after severe traumatic brain injury assessed by cerebral microdialysis with 300 kDa membranes

BACKGROUND

A neuroinflammatory response that may lead to edema and secondary brain damage is elicited in severe traumatic brain injury (TBI). Previous studies using microdialysis (MD) membranes with 100 k Dalton (kDa) cut-off found a transient intracerebral release of cytokines and chemokines without significant correlations to clinical course, intracranial pressure (ICP) or metabolites. In this study, a (300 kDa) MD probe was used to measure the levels of cytokines and chemokines in relation to ICP and metabolites.

METHODS

Seven patients with severe TBI received 2 MD catheters. In four patients sufficient dialysate could be retrieved for analysis from both catheters. MD samples were analyzed bedside, then frozen and analyzed for chemokines and cytokines using a multiplex assay (Mesoscale Discovery).

RESULTS

MD sampling was performed from 9 to 350 h. In total, 17 chemokines and cytokines were detected. Of these, IL-6, IL-8, IP-10, MCP-1 and MIP-1β were consistently elevated, and investigated further in relation to metabolites, and ICP. Levels of chemokines and cytokines were higher than previously reported from TBI patients, and partially higher than those reported in patients with cytokine release syndrome. There were no significant differences between the two catheters regarding cytokine/chemokine concentrations, except for IL-6 which was higher in the peri-contusional area. No correlation with metabolites and ICP was observed. No significant increase or decline of chemokine or cytokine secretion was observed during the study period.

CONCLUSION

Our data suggest that cytokine and chemokine levels reflect a perpetual, potent and pan-cerebebral inflammatory response that persists beyond 15 days following TBI.

Do prescription stimulants increase risk of Parkinson's disease among adults with attention-deficit hyperactivity disorder? A retrospective cohort study

BACKGROUND

Parkinson's disease (PD) is a common neurodegenerative disorder in older adults that is associated with neuroinflammation, oxidative stress, and characterized by loss of dopaminergic cells. Illicit stimulants increase oxidative stress and are associated with increased risk of PD. Prescription stimulants are similar in mechanism to illicit stimulants, yet their influence on PD is not well described. This study aims to determine if prescription stimulants influence risk of PD among older adults with attention-deficit and hyperactivity disorder (ADHD).

METHODS

We implemented a retrospective observational cohort design utilizing the TriNetX database which sources from the electronic health records of 57 healthcare organizations. Inclusion criteria were ADHD diagnosis and age ≥50. Those exposed to stimulants and the unexposed controls were matched based on demographics and known risk factors for PD. The outcome of interest was the incidence of PD over a 30-year follow-up period. We utilized TriNetX software for hazard ratio (HR) analysis.

RESULTS

Among the 59,471 individuals treated with prescription stimulants 131 of them developed PD, and there were 272 individuals who developed PD that were not prescribed stimulants. This analysis yielded a HR of 0.419 (HR = 0.419 [95% CI 0.34, 0.516], P = 0.0013).

CONCLUSION

Illicit stimulants are associated with increased risk of PD, but this study suggests prescribed stimulants may not impart that same risk. The reduced risk in this cohort may be due to protection from illicit substance use and oxidative stress, however additional study exploring the relationship between prescription stimulants and PD is warranted.

Autophagy and Apoptosis in Acute Brain Injuries: From Mechanism to Treatment

Significance: Autophagy and apoptosis are two important cellular mechanisms behind brain injuries, which are severe clinical situations with increasing incidences worldwide. To search for more and better treatments for brain injuries, it is essential to deepen the understanding of autophagy, apoptosis, and their interactions in brain injuries. This article first analyzes how autophagy and apoptosis participate in the pathogenetic processes of brain injuries respectively and mutually, then summarizes some promising treatments targeting autophagy and apoptosis to show the potential clinical applications in personalized medicine and precision medicine in the future. Recent Advances: Most current studies suggest that apoptosis is detrimental to brain recovery. Several studies indicate that autophagy can cause unnecessary death of neurons after brain injuries, while others show that autophagy is beneficial for acute brain injuries (ABIs) by facilitating the removal of damaged proteins and organelles. Whether autophagy is beneficial or detrimental in ABIs depends on many factors, and the results from different research groups are diverse or even controversial, making this topic more appealing to be explored further. Critical Issues: Neuronal autophagy and apoptosis are two primary pathological processes in ABIs. How they interact with each other and how their regulations affect the outcome and prognosis of brain injuries remain uncertain, making these answers more critical. Future Directions: Insights into the interplay between autophagy and apoptosis and the accurate regulations of their balance in ABIs may promote personalized and precise treatments in the field of brain injuries. Antioxid. Redox Signal. 38, 234-257.

Activity of a Novel Anti-Inflammatory Agent F-3,6'-dithiopomalidomide as a Treatment for Traumatic Brain Injury

Traumatic brain injury (TBI) is a major risk factor for several neurodegenerative disorders, including Parkinson's disease (PD) and Alzheimer's disease (AD). Neuroinflammation is a cause of later secondary cell death following TBI, has the potential to aggravate the initial impact, and provides a therapeutic target, albeit that has failed to translate into clinical trial success. Thalidomide-like compounds have neuroinflammation reduction properties across cellular and animal models of TBI and neurodegenerative disorders. They lower the generation of proinflammatory cytokines, particularly TNF-α which is pivotal in microglial cell activation. Unfortunately, thalidomide-like drugs possess adverse effects in humans before achieving anti-inflammatory drug levels. We developed F-3,6'-dithiopomalidomide (F-3,6'-DP) as a novel thalidomide-like compound to ameliorate inflammation. F-3,6'-DP binds to cereblon but does not efficiently trigger the degradation of the transcription factors (SALL4, Ikaros, and Aiolos) associated with the teratogenic and anti-proliferative responses of thalidomide-like drugs. We utilized a phenotypic drug discovery approach that employed cellular and animal models in the selection and development of F-3,6'-DP. F-3,6'-DP significantly mitigated LPS-induced inflammatory markers in RAW 264.7 cells, and lowered proinflammatory cytokine/chemokine levels in the plasma and brain of rats challenged with systemic LPS. We subsequently examined immunohistochemical, biochemical, and behavioral measures following controlled cortical impact (CCI) in mice, a model of moderate TBI known to induce inflammation. F-3,6'-DP decreased CCI-induced neuroinflammation, neuronal loss, and behavioral deficits when administered after TBI. F-3,6'-DP represents a novel class of thalidomide-like drugs that do not lower classical cereblon-associated transcription factors but retain anti-inflammatory actions and possess efficacy in the treatment of TBI and potentially longer-term neurodegenerative disorders.

Unilateral Cervical Vagotomy Modulates Immune Cell Profiles and the Response to a Traumatic Brain Injury

TBI induces splenic B and T cell expansion that contributes to neuroinflammation and neurodegeneration. The vagus nerve, the longest of the cranial nerves, is the predominant parasympathetic pathway allowing the central nervous system (CNS) control over peripheral organs, including regulation of inflammatory responses. One way this is accomplished is by vagus innervation of the celiac ganglion, from which the splenic nerve innervates the spleen. This splenic innervation enables modulation of the splenic immune response, including splenocyte selection, activation, and downstream signaling. Considering that the left and right vagus nerves have distinct courses, it is possible that they differentially influence the splenic immune response following a CNS injury. To test this possibility, immune cell subsets were profiled and quantified following either a left or a right unilateral vagotomy. Both unilateral vagotomies caused similar effects with respect to the percentage of B cells and in the decreased percentage of macrophages and T cells following vagotomy. We next tested the hypothesis that a left unilateral vagotomy would modulate the splenic immune response to a traumatic brain injury (TBI). Mice received a left cervical vagotomy or a sham vagotomy 3 days prior to a fluid percussion injury (FPI), a well-characterized mouse model of TBI that consistently elicits an immune and neuroimmune response. Flow cytometric analysis showed that vagotomy prior to FPI resulted in fewer CLIP+ B cells, and CD4+, CD25+, and CD8+ T cells. Vagotomy followed by FPI also resulted in an altered distribution of CD11bhigh and CD11blow macrophages. Thus, transduction of immune signals from the CNS to the periphery via the vagus nerve can be targeted to modulate the immune response following TBI.

Astrocyte-targeted Overproduction of IL-10 Reduces Neurodegeneration after TBI

Traumatic brain injury is the greatest cause of disability and death in young adults in the developed world. The outcome for a TBI patient is determined by the severity of the injury, not only from the initial insult but, especially, as a product of the secondary injury. It is proposed that this secondary injury is directly linked to neuro-inflammation, with the production of pro-inflammatory mediators, activation of resident glial cells and infiltration of peripheral immune cells. In this context, anti-inflammatory treatments are one of the most promising therapies to dampen the inflammatory response associated with TBI and to reduce secondary injury. In this sense, the main objective of the present study is to elucidate the effect of local production of IL-10 in the neurological outcome after TBI. For this purpose, a cryogenic lesion was caused in transgenic animals overproducing IL-10 under the GFAP promoter on astrocytes (GFAP-IL10Tg mice) and the neuro-protection, microglial activation and leukocyte recruitment were evaluated. Our results showed a protective effect of IL-10 on neurons at early time-points after TBI, in correlation with a shift in the microglial activation profile towards a down-regulating phenotype and lower production of pro-inflammatory cytokines. Concomitantly, we observed a reduction in the BBB leakage together with modifications in leukocyte infiltration into the affected area. In conclusion, local IL-10 production modifies the neuro-inflammatory response after TBI, shifting it to anti-inflammatory and neuro-protective conditions. These results point to IL-10 as a promising candidate to improve neuro-inflammation associated with TBI.

Systemic White Blood Cell Count as a Biomarker for Malignant Cerebral Edema in Large Vessel Ischemic MCA Stroke

OBJECTIVES

Large middle cerebral artery (MCA) strokes remain a major cause for mortality and morbidity all over the world, and therefore early identification of patients with the highest risk for malignant cerebral edema is crucial for early intervention. Neutrophils to lymphocytes ratio (NLR) and peripheral total white blood cell (WBC) count are inflammatory markers done routinely for all patients, and this study evaluated the use of NLR and elevated white blood cell count within the first 24 h of MCA ischemic stroke onset, with the absence of significant hemorrhagic transformation, to predict malignant cerebral edema.

MATERIALS AND METHODS

A total of 156 patients with large MCA strokes were included. We collected demographic, clinical, radiological data, and NLR and WBCs within the first 24 h from admission.We excluded patients who had any underlying infections diagnosed 7 days before or within 72 h after admission. We used a body temp of 38 C or more, abnormal CXR or abnormal urine analysis within the first 72 h to exclude patients with possible infections.We excluded immune-compromised patients and patients on steroid therapy. We compared the NLR and WBC count in patients who developed malignant cerebral edema versus the patients who did not. NLR > 3.5 and < 3.5 was used for comparison. We then conducted multivariate logistic regression models to explore the relationship between cerebral edema, WBCs and NLR count simultaneously.

RESULTS

NLR, WBC, radiological involvement of more than 50% of MCA territory infarction on presentation, hyperdense MCA sign, and NIH stroke scale were all significantly higher in patients with malignant cerebral edema within the first 24 h. Using univariate logistic regression, NLR performs better than WBC when predicting the occurrence of malignant cerebral edema (AUC = 0.74 vs. 0.62). However, NIH stroke scale scores, and radiological involvement of more than 50% of MCA territory infarction on the first 24 h of presentation on CT scan both showed better discriminative performance for malignant cerebral edema than NLR (AUC = 0.84 and 0.76, respectively). When combined, NLR > 3.5 paired with the NIH stroke scale score had the best predictive performance (AUC = 0.87).

CONCLUSION

NLR > 3.5 can be used for early prognostication in patients with large vessel MCA ischemic strokes with no significant hemorrhagic transformation within the first 24 h regardless if they had reperfusion therapy or not. Combining NLR of > 3.5 in addition to high NIHSS provided the best predictive model in our study. Further studies are needed to further develop the best predictive model in diverse populations.

Saffron extract and crocin exert anti-inflammatory and anti-oxidative effects in a repetitive mild traumatic brain injury mouse model

Saffron Crocus sativus L. (C. sativus) is a flower from the iridaceous family. Crocin, saffron’s major constituent, and saffron have anti-oxidative and anti-inflammatory activities. In this work, the neuroprotective effects of saffron and crocin are being investigated in a repetitive mild traumatic brain injury (rmTBI) mouse model. A weight drop model setup was employed to induce mild brain injury in male albino BABL/c mice weighing 30–40 g. Saffron (50 mg/kg) and crocin (30 mg/kg) were administrated intraperitoneally 30 min before mTBI induction. Behavioral tests were conducted to assess behavioral deficits including the modified neurological severity score (NSS), Morris water maze (MWM), pole climb test, rotarod test, and adhesive test. The levels of TNF alpha (TNF-α), interferon-gamma (IFN-γ), myeloperoxidase activity (MPO), malonaldehyde (MDA), and reduced glutathione (GSH) were measured. Histological analysis of different brain parts was performed. Both saffron and crocin demonstrated marked improved neurological, cognitive, motor, and sensorimotor functions. Besides, both compounds significantly reduced the oxidative stress and inflammatory processes. No abnormal histological features were observed in any of the injured groups. Saffron extract and crocin provide a neuroprotective effect in a mouse model of rmTBI by decreasing oxidative stress, inflammatory responses, and behavioral deficits.

Pre-clinical study of human umbilical cord mesenchymal stem cell transplantation for the treatment of traumatic brain injury: safety evaluation from immunogenic and oncogenic perspectives

Stem cell therapy is a promising strategy for the treatment of traumatic brain injury (TBI). However, animal experiments are needed to evaluate safety; in particular, to examine the immunogenicity and tumorigenicity of human umbilical cord mesenchymal stem cells (huMSCs) before clinical application. In this study, huMSCs were harvested from human amniotic membrane and umbilical cord vascular tissue. A rat model of TBI was established using the controlled cortical impact method. Starting from the third day after injury, the rats were injected with 10 μL of 5 × 10⁶/mL huMSCs by cerebral stereotaxis or with 500 μL of 1 × 10⁶/mL huMSCs via the tail vein for 3 successive days. huMSC transplantation decreased the serum levels of proinflammatory cytokines in rats with TBI and increased the serum levels of anti-inflammatory cytokines, thereby exhibiting good immunoregulatory function. The transplanted huMSCs were distributed in the liver, lung and brain injury sites. No abnormal proliferation or tumorigenesis was found in these organs up to 12 months after transplantation. The transplanted huMSCs negligibly proliferated in vivo, and apoptosis was gradually observed at later stages. These findings suggest that huMSC transplantation for the treatment of traumatic brain injury displays good safety. In addition, huMSCs exhibit good immunoregulatory function, which can help prevent and reduce secondary brain injury caused by the rapid release of inflammatory factors after TBI. This study was approved by the Ethics Committee of Wuhan General Hospital of PLA (approval No. 20160054) on November 1, 2016.

Neonatal microglia and proteinase inhibitors-treated adult microglia improve traumatic brain injury in rats by resolving the neuroinflammation

Microglia participate in the regulation of neuroinflammation caused by traumatic brain injury (TBI). This research aimed to explore the repair effects of intracranial injection of neonatal microglia or protease-treated adult microglia on TBI in rat model. Lateral fluid percussion injury was used to establish rat brain injury model. E64 and serpinA3N were employed for the treatment of adult microglia. Cleaved caspase-3 level was analyzed through immunoblotting assay. Enzyme-linked immunosorbent assay was employed to analyze cytokine and chemokine levels. Astrocytosis and microgliosis were shown by immunofluorescence. The cognitive function of rats was analyzed by water maze. The injection of neonatal microglia inhibited cell apoptosis, reduced astrocytosis and microgliosis, decreased the level of chemokines and cytokines in cortex and ipsilateral hippocampus, and improved cognitive function of TBI rat model. The transplantation of peptidase inhibitors-treated adult microglia also inhibited cell apoptosis, reduced astrocytosis and microgliosis, and improved cognitive function of rats with TBI. The transplantation of either neonatal microglia or peptidase inhibitors-treated adult microglia significantly inhibited the pathogenesis of TBI in rat model, while untreated adult microglia showed no significant effect.

Effect of Vitamin D Supplementation on Inflammatory Biomarkers in School-Aged Children with Attention Deficit Hyperactivity Disorder

METHOD

This randomized double-blind, placebo-controlled trial was conducted on 75 school-aged children with a diagnosis of ADHD based on DSM-V criteria. Children were randomly allocated to receive either vitamin D3 (2000 IU/day) or a placebo for 3 months. Serum IL-6, TNF-α, and 25(OH) D were assessed before and after the intervention to determine the effects of vitamin D on the highlighted parameters.

RESULTS

Serum levels of 25(OH) D increased significantly in the vitamin D group (P=0.01). However, no significant differences in serum IL-6 and TNF-α were found between both groups at the baseline and at the end of the intervention.

CONCLUSION

The findings revealed that vitamin D supplementation for 3 months is not efficacious in reducing inflammatory cytokines in children with ADHD. Further studies are required to confirm these results.

Possible involvement of female sex steroid hormones in intracellular signal transduction mediated by cytokines following traumatic brain injury

INTRODUCTION

The aim of this study was to determine the anti-inflammatory effect of female sex hormones on the level of intracellular molecules of cytokine signaling pathway after diffuse traumatic brain injury (TBI) in ovariectomized rats.

METHODS

Female rats were divided into 10 groups: control, sham, TBI, Vehicle (oil), Vehicle E1 (33.3 µg/kg), E2 (1 mg / kg), P1 (1.7 mg/kg), P2 (8 mg / kg), E2 + P1. All drugs were injected 0.5 h after TBI. Brain edema and the brain levels of P-STAT-3, NFκB-P52, NFκB-P65, P-IκB, and SOCS-3 by immunohistochemistry measured at 24 h after TBI.

RESULTS

Increased brain edema after TBI was inhibited by different doses of estrogen, progesterone (P < 0.001), and E2 + P1 (P < 0.05). The brain levels of P-STAT-3, NFκB-P52, NFκB-P65, and p-IκBα that increased after TBI was decreased only by E2 (P < 0.05). E2 and E2 + P1 have increased the SOCS-3 level after TBI (P < 0.05). Also, there was a difference between the E2 with E1 and two progesterone doses (P < 0.05). So that in all cases, the effects of E2 were more significant than the other groups. The target cells for these effects of E2 were microglia and astrocytes.

CONCLUSION

The results indicate that one of the probable mechanism(s) of estrogen anti-inflammatory effect after TBI is either reduction of p-STAT-3, NFκB-P52, p-NFκB-P65, and p-IκBα or increase in SOCS-3 molecules involved in the signaling pathway of inflammatory cytokines.

The Neurobehavioral Effects of Buprenorphine and Meloxicam on a Blast-Induced Traumatic Brain Injury Model in the Rat

Previous findings have indicated that pain relieving medications such as opioids and non-steroidal anti-inflammatory drugs (NSAIDs) may be neuroprotective after traumatic brain injury in rodents, but only limited studies have been performed in a blast-induced traumatic brain injury (bTBI) model. In addition, many pre-clinical TBI studies performed in rodents did not use analgesics due to the possibility of neuroprotection or other changes in cognitive, behavioral, and pathology outcomes. To examine this in a pre-clinical setting, we examined the neurobehavioral changes in rats given a single pre-blast dose of meloxicam, buprenorphine, or no pain relieving medication and exposed to tightly-coupled repeated blasts in an advanced blast simulator and evaluated neurobehavioral functions up to 28 days post-blast. A 16.7% mortality rate was recorded in the rats treated with buprenorphine, which might be attributed to the physiologically depressive side effects of buprenorphine in combination with isoflurane anesthesia and acute brain injury. Rats given buprenorphine, but not meloxicam, took more time to recover from the isoflurane anesthesia given just before blast. We found that treatment with meloxicam protected repeated blast-exposed rats from vestibulomotor dysfunctions up to day 14, but by day 28 the protective effects had receded. Both pain relieving medications seemed to promote short-term memory deficits in blast-exposed animals, whereas vehicle-treated blast-exposed animals showed only a non-significant trend toward worsening short-term memory by day 27. Open field exploratory behavior results showed that blast exposed rats treated with meloxicam engaged in significantly more locomotor activities and possibly a lesser degree of responses thought to reflect anxiety and depressive-like behaviors than any of the other groups. Rats treated with analgesics to alleviate possible pain from the blast ate more than their counterparts that were not treated with analgesics, which supports that both analgesics were effective in alleviating some of the discomfort that these rats potentially experienced post-blast injury. These results suggest that meloxicam and, to a lesser extent buprenorphine alter a variety of neurobehavioral functions in a rat bTBI model and, because of their impact on these neurobehavioral changes, may be less than ideal analgesic agents for pre-clinical studies evaluating these neurobehavioral responses after TBI.

Saffron extract attenuates neuroinflammation in rmTBI mouse model by suppressing NLRP3 inflammasome activation via SIRT1

Traumatic brain injury (TBI) remains a major cause of morbidity and disability worldwide and a healthcare burden. TBI is an important risk factor for neurodegenerative diseases hallmarked by exacerbated neuroinflammation. Neuroinflammation in the cerebral cortex plays a critical role in secondary injury progression following TBI. The NOD-like receptors (NLR) family pyrin domain containing 3 (NLRP3) inflammasome is a key player in initiating the inflammatory response in various central nervous system disorders entailing TBI. This current study aims to investigate the role of NLRP3 in repetitive mild traumatic brain injury (rmTBI) and identify the potential neuroprotective effect of saffron extract in regulating the NLRP3 inflammasome. 24 hours following the final injury, rmTBI causes an upregulation in mRNA levels of NLRP3, caspase-1, the apoptosis-associated speck-like protein containing a CARD (ASC), nuclear factor kappa B (NF-κB), interleukin-1Beta (IL-1β), interleukin 18 (IL-18), nuclear factor erythroid 2-related factor 2 (NRF2) and heme oxygenase 1 (HMOX1). Protein levels of NLRP3, sirtuin 1 (SIRT1), glial fibrillary acidic protein (GFAP), ionized calcium-binding adaptor molecule 1 (Iba1), and neuronal nuclei (Neu N) also increased after rmTBI. Administration of saffron alleviated the degree of TBI, as evidenced by reducing the neuronal damage, astrocyte, and microglial activation. Pretreatment with saffron inhibited the activation of NLRP3, caspase-1, and ASC concurrent to reduced production of the inflammatory cytokines IL-1β and IL-18. Additionally, saffron extract enhanced SIRT1 expression, NRF2, and HMOX1 upregulation. These results suggest that NLRP3 inflammasome activation and the subsequent inflammatory response in the mice cortex are involved in the process of rmTBI. Saffron blocked the inflammatory response and relieved TBI by activating detoxifying genes and inhibiting NLRP3 activation. The effect of saffron on the NLRP3 inflammasome may be SIRT1 and NF-κB dependent in the rmTBI model. Thus, brain injury biomarkers will help in identifying a potential therapeutic target in treating TBI-induced neurodegenerative diseases.

Nervous System Involvement in COVID-19: a Review of the Current Knowledge

The current pandemic of the new human coronavirus (CoV), i.e., severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has created an urgent global condition. The disease, termed coronavirus disease 2019 (COVID-19), is primarily known as a respiratory tract infection. Although SARS-CoV-2 directly invades the lungs, COVID-19 is a complex multi-system disease with varying degrees of severity and affects several human systems including the cardiovascular, respiratory, gastrointestinal, neurological, hematopoietic, and immune systems. From the existing data, most COVID-19 cases develop a mild disease typically presented with fever and respiratory illness. However, in some patients, clinical evidence suggests that COVID-19 might progress to acute respiratory distress syndrome (ARDS), multi-organ dysfunction, and septic shock resulting in a critical condition. Likewise, specific organ dysfunction seems to be related to the disease complication, worsens the condition, and increases the lethality of COVID-19. The neurological manifestations in association with disease severity and mortality have been reported in COVID-19 patients. Despite the continuously increasing reports of the neurological symptoms of SARS-CoV-2, our knowledge about the possible routes of nervous system involvement associated with COVID-19 is limited. Herein, we will primarily describe the critical aspects and clinical features of SARS-CoV-2 related to nervous system impairment and then discuss possible routes of SARS-CoV-2 nervous system involvement based on the current evidence.

Levels of Biological Markers of Nitric Oxide in Serum of Patients with Mandible Fractures

Background: Nitric oxide is a small gaseous molecule with significant bioactivity. It has been observed that NO may have a dual role dependent on its production and concentrations in the bone microenvironment. The objective of the study was to assess the concentration of total nitric oxide malonyldialdehyde, nitrotyrosine, and asymmetric dimethylarginine in the serum of patients with mandibular fractures and to understand the relationship between these compounds, in order to expand the knowledge base of the role of nitric oxide and its activity indicators in the process of bone fracture healing. Material and Methods: The study included 20 patients with mandibular fractures who were undergoing inpatient and outpatient treatments and a control group of 15 healthy people. Results were analyzed with respect to the measurement time. Total nitric oxide concentration in the blood serum was determined according to the Griess reaction, while the concentration of malonyldialdehyde, nitrotyrosine, and asymmetric dimethylarginine was estimated using the immunoenzymatic method (i.e., enzyme-linked immunosorbent assay). Results: Before the procedure, as well as on the first day and 2 and 6 weeks after the procedure, higher concentrations of total nitric oxide and lower concentrations of malonyldialdehyde were observed in the blood serum of patients with mandibular fractures compared to the control group. No statistically significant differences were found in nitrotyrosine concentrations in the blood serum of patients throughout the measurement period. However, a significantly higher asymmetric dimethylarginine concentration was observed in the patient serum before the procedure and on the first day of operation as compared with the control group. Analysis of the results observed in patient serum with respect to the number of fractures within the mandible demonstrated the same trend of concentrations for the tested compounds for the entire study group. Conclusions: In summary, our results revealed that the intensity of local processes resulting from mandibular fractures is associated with the concentration of nitric oxide, confirming its significant role, as well as that of its indicators, in the process of bone fracture healing in this patient population.

Cathepsin C aggravates neuroinflammation via promoting production of CCL2 and CXCL2 in glial cells and neurons in a cryogenic brain lesion

OBJECTIVE

Chemokines regulate infiltration of immune cells to brain in inflammation. Cathepsin C (CatC), a lysosomal protease, has been found to participate in neuroinflammation. However, how CatC affects chemokines expression in neuroinflammation triggered by traumatic brain injury (TBI) remains unclear. Here, we investigated the effects of CatC on chemokines and neuroinflammation in TBI.

METHODS

The present study used CatC knockdown (KD) and overexpression (OE) mice to generate cryogenic brain lesion model and determined effects of CatC on expression of chemokines CCL2, CCL5 and CXCL2 and infiltration of immune cells in acute and chronic phases of the lesion. Further, cellular sources of various chemokines were demonstrated in vitro. Values were compared with wild type (WT) mice.

RESULTS

The results found that 6 h after lesion, CatC expression,IL-1β and TNF-α mRNA and protein expression were strongly induced in the lesions; CCL2 and CXCL2 mRNA and protein expression were increased in CatC OE mice, while decreased in CatC KD mice. On the 3rd day after lesion, macrophages and neutrophils were mainly infiltrated to the lesions. Simultaneously, Iba-1+ cells in CatC OE mice were increased, while MPO + cells in CatC KD mice were decreased. In contrast, on the 28th day after lesion, a few lymphocytes were infiltrated surrounding new blood vessels. CatC OE mice showed larger volumes of scar areas, higher expression of CCL2,CXCL2,IL-1β,TNF-α,IL-6 and iNOS, as well as stronger GFAP+ and Iba-1+ signals, while CatC KD mice had reversed effects. No significant differences of CCL5 expression were found in various genotype mice. Further, in vitro study demonstrated CatC-induced expression of CCL2 were mainly derived from microglia and neurons, while CXCL2 derived from microglia and astrocytes.

CONCLUSION

Our data indicate that CatC aggravates neuroinflammation via promoting production of CCL2 and CXCL2 in glial cells and neurons in a cryogenic brain lesion, providing potential cellular and molecular targets for future intervention of TBI and other neuroinflammatory diseases.

Endothelial glycocalyx in traumatic brain injury associated coagulopathy: potential mechanisms and impact

Traumatic brain injury (TBI) remains one of the leading causes of death and disability worldwide; more than 10 million people are hospitalized for TBI every year around the globe. While the primary injury remains unavoidable and not accessible to treatment, the secondary injury which includes oxidative stress, inflammation, excitotoxicity, but also complicating coagulation abnormalities, is potentially avoidable and profoundly affects the therapeutic process and prognosis of TBI patients. The endothelial glycocalyx, the first line of defense against endothelial injury, plays a vital role in maintaining the delicate balance between blood coagulation and anticoagulation. However, this component is highly vulnerable to damage and also difficult to examine. Recent advances in analytical techniques have enabled biochemical, visual, and computational investigation of this vascular component. In this review, we summarize the current knowledge on (i) structure and function of the endothelial glycocalyx, (ii) its potential role in the development of TBI associated coagulopathy, and (iii) the options available at present for detecting and protecting the endothelial glycocalyx.

Fibrinogen Interaction with Astrocyte ICAM-1 and PrPC Results in the Generation of ROS and Neuronal Death

Many neuroinflammatory diseases, like traumatic brain injury (TBI), are associated with an elevated level of fibrinogen and short-term memory (STM) impairment. We found that during TBI, extravasated fibrinogen deposited in vasculo-astrocyte interfaces, which was associated with neurodegeneration and STM reduction. The mechanisms of this fibrinogen-astrocyte interaction and its functional role in neurodegeneration are still unclear. Cultured mouse brain astrocytes were treated with fibrinogen in the presence or absence of function-blocking antibody or peptide against its astrocyte receptors intercellular adhesion molecule-1 (ICAM-1) or cellular prion protein (PrP^C), respectively. Fibrinogen interactions with astrocytic ICAM-1 and PrP^C were characterized. The expression of pro-inflammatory markers, generations of reactive oxygen species (ROS) and nitric oxide (NO) in astrocytes, and neuronal death caused by astrocyte-conditioned medium were assessed. Data showed a strong association between fibrinogen and astrocytic ICAM-1 or PrP^C, overexpression of pro-inflammatory cytokines and overproduction of ROS and NO, resulting in neuronal apoptosis and death. These effects were reduced by blocking the function of astrocytic ICAM-1 and PrP^C, suggesting that fibrinogen association with its astrocytic receptors induce the release of pro-inflammatory cytokines, resulting in oxidative stress, and ultimately neuronal death. This can be a mechanism of neurodegeneration and the resultant STM reduction seen during TBI.

Astrocyte-derived extracellular vesicles: A double-edged sword in central nervous system disorders

Recent studies suggest that astrocytes released a great quantity of extracellular vesicles (AEVs) to communicate with other brain cells. Under pathological conditions, AEVs are widely associated with the pathogenesis of neurobiological diseases by horizontally transferring pathogenic factors to neighboring cells or peripheral immune cells. Their beneficial role is also evident by the fact that they are involved in neuroprotection and neuroregeneration through alleviating apoptosis, maintaining neuronal function, and repairing neural injuries. The strong association of AEVswith neurological disorders makes AEVs a promising target for disease diagnosis, treatment, and prevention. The identification of disease-specific cargos in AEVs isolated from the patients' biofluids suggests AEVs as an attractive platform for biomarker development. Furthermore, the inhibition of inflammatory/toxic AEV release and the preservation of neuroprotective AEV release have been considered as potential therapeutic strategies in CNS disorder treatment and prevention, respectively. Here, we summarize the biological roles of AEVs as pathological contributors, protective/regenerative factors, and potential diagnostic biomarkers and therapeutic targets for neurological disorders, with a focus on recent progresses and emerging concepts.

Coadministration of Ketamine and Perampanel Improves Behavioral Function and Reduces Inflammation in Acute Traumatic Brain Injury Mouse Model

Traumatic brain injury (TBI) is among the most debilitating neurological disorders with inadequate therapeutic options. It affects all age groups globally leading to post-TBI behavioral challenges and life-long disabilities requiring interventions for these health issues. In the current study, C57BL/6J mice were induced with TBI through the weight-drop method, and outcomes of acutely administered ketamine alone and in combination with perampanel were observed. The impact of test drugs was evaluated for post-TBI behavioral changes by employing the open field test (OFT), Y-maze test, and novel object recognition test (NOR). After that, isolated plasma and brain homogenates were analyzed for inflammatory modulators, i.e., NF-κB and iNOS, through ELISA. Moreover, metabolomic studies were carried out to further authenticate the TBI rescuing potential of drugs. The animals treated with ketamine-perampanel combination demonstrated improved exploratory behavior in OFT (P < 0.05), while ketamine alone as well as in combination yielded anxiolytic effect (P < 0.05-0.001) in posttraumatic mice. Similarly, the % spontaneous alternation and % discrimination index were increased after the administration of ketamine alone (P < 0.05) and ketamine-perampanel combination (P < 0.01-0.001) in the Y-maze test and NOR test, respectively. ELISA demonstrated the reduced central and peripheral expression of NF-κB (P < 0.05) and iNOS (P < 0.01-0.0001) after ketamine-perampanel polypharmacy. The TBI-imparted alteration in plasma metabolites was restored by drug combination as evidenced by metabolomic studies. The outcomes were fruitful with ketamine, but the combination therapy proved more significant in improving all studied parameters. The benefits of this new investigated polypharmacy might be due to their antiglutamatergic, antioxidant, and neuroprotective capacity.

Acute damage to the blood–brain barrier and perineuronal net integrity in a clinically-relevant rat model of traumatic brain injury

Closed-head, frontal impacts in which the brain undergoes both lateral and rotational acceleration comprise the majority of human traumatic brain injury (TBI). Here, we utilize a clinically relevant model to examine the effects of a single concussion on aspects of brain integrity: the blood-brain barrier, the perineuronal nets (PNNs), and diffuse axonal injury. Adult, male Sprague-Dawley rats received either a frontal, closed-head concussive TBI, or no injury and were evaluated at 1- or 7-day post-injury. Using immunolabeling for albumin, we observed a significant increase in the permeability of the blood-brain barrier at 1-, but not 7-day post-injury. Breakdown of the PNN, as measured by the binding of wisteria floribunda, was observed at 1-day post-injury in the dorsal, lateral, and ventral cortices. This difference was resolved at 7-day. Finally, axonal injury was identified at both 1- and 7-day post-injury. This preclinical model of closed-head, frontal TBI presents a useful tool with which to understand better the acute pathophysiology of a single, frontal TBI.

Drugs with anti-inflammatory effects to improve outcome of traumatic brain injury: a meta-analysis

Outcome after traumatic brain injury (TBI) varies largely and degree of immune activation is an important determinant factor. This meta-analysis evaluates the efficacy of drugs with anti-inflammatory properties in improving neurological and functional outcome. The systematic search following PRISMA guidelines resulted in 15 randomized placebo-controlled trials (3734 patients), evaluating progesterone, erythropoietin and cyclosporine. The meta-analysis (15 studies) showed that TBI patients receiving a drug with anti-inflammatory effects had a higher chance of a favorable outcome compared to those receiving placebo (RR = 1.15; 95% CI 1.01–1.32, p = 0.041). However, publication bias was indicated together with heterogeneity (I² = 76.59%). Stratified analysis showed that positive effects were mainly observed in patients receiving this treatment within 8 h after injury. Subanalyses by drug type showed efficacy for progesterone (8 studies, RR 1.22; 95% CI 1.01–1.47, p = 0.040), again heterogeneity was high (I² = 62.92%) and publication bias could not be ruled out. The positive effect of progesterone covaried with younger age and was mainly observed when administered intramuscularly and not intravenously. Erythropoietin (4 studies, RR 1.20; p = 0.110; I² = 76.59%) and cyclosporine (3 studies, RR 0.75; p = 0.189, I² = 0%) did not show favorable significant effects. While negative findings for erythropoietin may reflect insufficient power, cyclosporine did not show better outcome at all. Current results do not allow firm conclusions on the efficacy of drugs with anti-inflammatory properties in TBI patients. Included trials showed heterogeneity in methodological and sample parameters. At present, only progesterone showed positive results and early administration via intramuscular administration may be most effective, especially in young people. The anti-inflammatory component of progesterone is relatively weak and other mechanisms than mitigating overall immune response may be more important.

The effects of glial cells inhibition on spatial reference, reversal and working memory deficits in a rat model of traumatic brain injury (TBI)

AIMS

Evidence suggests that glial cells are influenced by Traumatic brain injury (TBI). Both protective and damaging roles have been attributed to reactive glial cells, but their role after TBI has not been well understood. In this study, the role of glial cells in TBI-induced cognitive impairment was investigated.

MATERIALS AND METHODS

Male rats were randomly assigned to the following groups: Sham + PBS, sham + FC, TBI + PBS, and TBI + FC. FC (1 nmol/1 μl), a glial cell inhibitor, was injected into the lateral ventricle 10 min after TBI induction and it was repeated every 24 h until the seventh day. On days 8-13 post-injury, reference and reverse memory and on days 8-16 post-injury, working memory was assessed using the Morris water maze test.

RESULTS

Brain-injured rats exhibited significant impairments in acquisition and retrieval phases of reference and reverse memory compared to sham rats and FC administration could not attenuate the deteriorative effect of TBI in different learning tasks. TBI rats showed impairment in acquisition (but not retrieval) of working memory. Sham animals which received FC showed a deficit in reversal memory acquisition and retrieval of reference memory compared to sham + PBS rats.

CONCLUSION

The present study demonstrates that memory deficit induced by TBI cannot be improved by FC, and glial cells inhibition in uninjured animals causes impairments in reversal memory acquisition and retrieval of reference memory. Our results suggest that in addition to essential role of glial cells for memory formation in normal situation, their responses after TBI may have preventive effect against memory impairments.

Fibrinogen and Neuroinflammation During Traumatic Brain Injury

Many neurodegenerative diseases such as Alzheimer's disease (AD), multiple sclerosis, and traumatic brain injury (TBI) are associated with systemic inflammation. Inflammation itself results in increased blood content of fibrinogen (Fg), called hyperfibrinogenemia (HFg). Fg is not only considered an acute phase protein and a marker of inflammation, but has been shown that it can cause inflammatory responses. Fibrin deposits have been associated with memory reduction in neuroinflammatory diseases such as AD and TBI. Reduction in short-term memory has been seen during the most common form of TBI, mild-to-moderate TBI. Fibrin deposits have been found in brains of patients with mild-to-moderate TBI. The vast majority of the literature emphasizes the role of fibrin-activated microglia as the mediator in the neuroinflammation pathway. However, the recent discovery that astrocytes, which constitute approximately 30% of the cells in the mammalian central nervous system, manifest different reactive states warrants further investigations in the causative role of HFg in astrocyte-mediated neuroinflammation. Our previous study showed that Fg deposited in the vasculo-astrocyte interface-activated astrocytes. However, little is known of how Fg directly affects astrocytes and neurons. In this review, we summarize studies that show the effect of Fg on different types of cells in the vasculo-neuronal unit. We will also discuss the possible mechanism of HFg-induced neuroinflammation during TBI.

Tumor Necrosis Factor-α, the Pathological Key to Post-Traumatic Epilepsy: A Comprehensive Systematic Review

Post-traumatic epilepsy (PTE) is one of the detrimental outcomes of traumatic brain injury (TBI), resulting in recurrent seizures that impact daily life. However, the pathological relationship between PTE and TBI remains unclear, and commonly prescribed antiepileptic drugs (AED) are ineffective against PTE. Fortunately, emerging research implicates neuroinflammation, particularly, tumor necrosis factor-α (TNF-α), as the key mediator for PTE development. Thus, this review aims to examine the available literature regarding the role of TNF-α in PTE pathology and, subsequently, evaluate TNF-α as a possible target for its treatment. A comprehensive literature search was conducted on four databases including PubMed, CINAHL, Embase, and Scopus. Articles with relevance in investigating TNF-α expression in PTE were considered in this review. Critical evaluation of four articles that met the inclusion criteria suggests a proportional relationship between TNF-α expression and seizure susceptibilit and that neutralization or suppression of TNF-α release results in reduced susceptibility to seizures. In conclusion, this review elucidates the importance of TNF-α expression in epileptogenesis postinjury and urges future research to focus more on clinical studies involving TNF-α, which may provide clearer insight into PTE prevention, therefore improving the lives of PTE patients.

Elevated intracranial pressure after head trauma can be suppressed by antisecretory factor-a pilot study

Background

Control of intracranial pressure (ICP) is a key element in neurointensive care for directing treatment decisions in patients with severe traumatic brain injury (TBI). The anti-inflammatory protein antisecretory factor (AF) has been demonstrated to reduce experimentally induced high ICP in animal models. This report describes the first steps to investigate the uptake, safety, and influence of AF for reduction of elevated ICP in patients with TBI in a clinical setting.

Method

Four patients with severe TBI (Glasgow Coma Scale < 9) that required neurointensive care with ICP monitoring due to signs of refractory intracranial hypertension were investigated. One hundred milliliters of Salovum®, a commercially available egg yolk powder with high contents of AF peptides, was administrated either via nasogastric (patients 1 and 2) or rectal tube (patients 2, 3, and 4) every 8 h for 2 to 3 days as a supplement to the conventional neurointensive care. ICP was registered continuously. Plasma levels of AF were measured by enzyme-linked immunosorbent assay (ELISA) to confirm that Salovum® was absorbed appropriately into the bloodstream.

Results

In the first two patients, we observed that when delivered by the nasogastric route, there was an accumulation of the Salovum® solution in the stomach with difficulties to control ICP due to impaired gastric emptying. Therefore, we tested to administer Salovum® rectally. In the third and fourth patients, who both showed radiological signs of extensive brain edema, ICP could be controlled during the course of rectal administration of Salovum®. The ICP reduction was statistically significant and was accompanied by an increase in blood levels of AF. No adverse events that could be attributed to AF treatment or the rectal approach for Salovum® administration were observed.

Conclusions

The outcomes suggest that AF can act as a suppressor of high ICP induced by traumatic brain edema. Use of AF may offer a new therapeutic option for targeting cerebral edema in clinical practice.

The Potassium SK Channel Activator NS309 Protects Against Experimental Traumatic Brain Injury Through Anti-Inflammatory and Immunomodulatory Mechanisms

Neuroinflammation plays important roles in neuronal cell death and functional deficits after TBI. Small conductance Ca²⁺-activated K⁺ channels (SK) have been shown to be potential therapeutic targets for treatment of neurological disorders, such as stroke and Parkinson’s disease (PD). The aim of the present study was to investigate the role of SK channels in an animal model of TBI induced by controlled cortical impact (CCI). The SK channels activator NS309 at a concentration of 2 mg/kg was administered by intraperitoneal injection, and no obviously organ-related toxicity of NS309 was found in Sprague-Dawley (SD) rats. Treatment with NS309 significantly reduced brain edema after TBI, but had no effect on contusion volume. This protection can be observed even when the administration was delayed by 4 h after injury. NS309 attenuated the TBI-induced deficits in neurological function, which was accompanied by the reduced neuronal apoptosis. The results of immunohistochemistry showed that NS309 decreased the number of neutrophils, lymphocytes, and microglia cells, with no effect on astrocytes. In addition, NS309 markedly decreased the levels of pro-inflammatory cytokines (IL-1β, IL-6 and TNF-α) and chemokines (MCP-1, MIP-2, and RANTES), but increased the levels of anti-inflammatory cytokines (IL-4, IL-10, and TGF-β1) after TBI. The results of RT-PCR and western blot showed that NS309 increased TSG-6 expression and inhibited NF-κB activation. Furthermore, knockdown of TSG-6 using in vivo transfection with TSG-6 specific shRNA partially reversed the protective and anti-inflammatory effects of NS309 against TBI. In summary, our results indicate that the SK channel activator NS309 could modulate inflammation-associated immune cells and cytokines via regulating the TSG-6/NF-κB pathway after TBI. The present study offers a new sight into the mechanisms responsible for SK channels activation with implications for the treatment of TBI.

EK7 Regulates NLRP3 Inflammasome Activation and Neuroinflammation Post-traumatic Brain Injury

As one of the most common causes of mortality and disability, traumatic brain injury (TBI) is a huge psychological and economic burden to patients, families, and societies worldwide. Neuroinflammation reduction may be a favorable option to alleviate secondary brain injuries and ameliorate the outcome of TBI. The nucleotide-binding oligomerization domain, leucine-rich repeat and pyrin domain-containing 3 (NLRP3) inflammasome, has been shown to be involved in TBI. NIMA-related kinase 7 (NEK7) has been verified as an essential mediator of NLRP3 inflammasome activation that is recruited upstream of the formation of inflammasomes in response to NLRP3 activators. However, the underlying mechanism by which NEK7 operates post-TBI remains undefined. In this study, we performed both in vivo and in vitro experiments. Using an in vivo mouse TBI model, mice were administered an intracerebroventricular injection of NEK7-shRNA virus. For the in vitro analysis, primary cortical neurons with NEK7-shRNA were stimulated with lipopolysaccharide (LPS)/ATP or potassium (K⁺). We evaluated the effects of NEK7 knock-down on neurological deficits, NLRP3 inflammasomes, caspase-1 activation, and neuronal injury. During the 0–168 h post-TBI period in vivo, NEK7 and NLRP3 inflammasome activation increased in what appeared to be a time-dependent manner. As well as pyroptosis-related markers, caspase-1 activation (p20) and interleukin-1β (IL-1β) activation (p17) were up-regulated. NEK7 down-regulation attenuated neurological deficits, NLRP3 inflammasomes, caspase-1 activation, and neuronal injury. The same phenomena were observed during the in vitro experiments. Furthermore, NEK7 knock-down suppressed NLRP3 inflammasome activation and pyroptosis, which were triggered by K⁺ efflux, and the LPS + ATP-triggered NEK7–NLRP3 complex was reversed in primary cortical neurons placed in 50 mM K⁺ medium. Collectively, the data demonstrated that NEK7, as a modulator, regulates NLRP3 inflammasomes and downstream neuroinflammation in response to K⁺ efflux, through NEK7–NLRP3 assembly, pro-caspase-1 recruitment, caspase-1 activation, and pyroptosis in nerve injuries, post-TBI. NEK7 may be a potential therapeutic target for attenuating neuroinflammation and nerve injury post-TBI.

Evaluation of IL-1β levels in epilepsy and traumatic brain injury in dogs

Background

Epilepsy is a common neurological disease in dogs affecting approximately 0.6–0.75% of the canine population. There is much evidence of neuroinflammation presence in epilepsy, creating new possibilities for the treatment of the disease. An increased expression of interleukin-1 beta (IL-1β) was reported in epileptogenic foci. We hypothesized that there is an elevation of IL-1β in serum and CSF of dogs with epilepsy, as well as in serum of dogs with TBI, reflecting involvement of this cytokine in pathophysiology of naturally occurring canine epilepsy in a clinical setting.

Results

IL-1β levels were evaluated in CSF and serum of six healthy and 51 dogs with epilepsy (structural and idiopathic). In 16 dogs with TBI, only serum was tested. IL-1β concentrations in CSF were not detectable. Serum values were not elevated in dogs with TBI in comparison to healthy controls (p > 0.05). However, dogs with epilepsy had increased levels of IL-1β in serum (p = 0.003) regardless of the underlying cause of the disease (p = 0.0045). There was no significant relationship between the variables and IL-1β levels. Statistically noticeable (p = 0.0630) was that approximately 10% of dog with epilepsy (R² = 0.105) had increased seizure frequency and IL-1β elevation.

Conclusion

Increased IL-1β levels were detected in the peripheral blood in dogs with idiopathic and structural epilepsy leading to the assumption that there is an involvement of inflammation in pathophysiology of epilepsy which should be considered in the search for new therapeutic strategies for this disease. However, to better understand the pathogenic role of this cytokine in epilepsy, further evaluation of IL-1β in brain tissue is desired.

Dynamic cell type-specific expression of Nrf2 after traumatic brain injury in mice

Nrf2 plays a pivotal role in antioxidant response and anti-inflammation after traumatic brain injury (TBI), and its deletion aggravates TBI-induced brain damage. Previous studies have demonstrated that Nrf2 is activated post TBI, but dynamic changes in expression and cell type-specific characteristics remain unclear. In this study, the Feeney weight-drop contusion model was conducted to mimic TBI, and the ipsilateral cerebral cortex was collected at 1, 3, 7 and 14 days post TBI (dpi). Nrf2 protein levels were observed by western blot. Cell type-specific localization of Nrf2 after TBI was detected at different time intervals by double immunofluorescence staining. NeuN, GFAP, IBA1 and NG2 were used as cell type-specific markers to neurons, astrocytes, microglia and NG2 glia, respectively. After TBI, Nrf2 protein levels peaked at 1 dpi. Robust transient Nrf2 accumulation was co-localized with neurons, which was predominant at 1 dpi. Continuous weak Nrf2 expression was detected in activated astrocytes, and the number of double positive cells peaked at 7 dpi. Inducible widespread immunostaining of Nrf2 was observed in the nucleus of the microglia, and the number of Nrf2+ microglia peaked at 7 dpi. In addition, we also explored colocalization of Nrf2 in NG2 glia, in which the percentage of Nrf2+ in NG2 glia reached a climax at 3 dpi. This study reveals that the accumulation of endogenous Nrf2 might mediate different pathophysical roles in neurons and glias after TBI, the cell-type specific and time-dependent expression provide insights to explain the roles of Nrf2 in different neural cells.

Acute Tubular Injury is Associated With Severe Traumatic Brain Injury: in Vitro Study on Human Tubular Epithelial Cells

Acute kidney injury following traumatic brain injury is associated with poor outcome. We investigated in vitro the effects of plasma of brain injured patients with acute tubular kidney injury on kidney tubular epithelial cell function. we performed a prospective observational clinical study in ICU in a trauma centre of the University hospital in Italy including twenty-three ICU patients with traumatic brain injury consecutively enrolled. Demographic data were recorded on admission: age 39 ± 19, Glasgow Coma Score 5 (3–8). Neutrophil Gelatinase-Associated Lipocalin and inflammatory mediators were measured in plasma on admission and after 24, 48 and 72 hours; urine were collected for immunoelectrophoresis having healthy volunteers as controls. Human renal proximal tubular epithelial cells were stimulated with patients or controls plasma. Adhesion of freshly isolated human neutrophils and trans-epithelial electrical resistance were assessed; cell viability (XTT assay), apoptosis (TUNEL staining), Neutrophil Gelatinase-Associated Lipocalin and Megalin expression (quantitative real-time PCR) were measured. All patients with normal serum creatinine showed increased plasmatic Neutrophil Gelatinase-Associated Lipocalin and increased urinary Retinol Binding Protein and α1-microglobulin. Neutrophil Gelatinase-Associated Lipocalin was significantly correlated with both inflammatory mediators and markers of tubular damage. Patient’ plasma incubated with tubular cells significantly increased adhesion of neutrophils, reduced trans-epithelial electrical resistance, exerted a cytotoxic effect and triggered apoptosis and down-regulated the endocytic receptor Megalin compared to control. Plasma of brain injured patients with increased markers of subclinical acute kidney induced a pro-inflammatory phenotype, cellular dysfunction and apoptotic death in tubular epithelial cells.

Sex differences in pediatric traumatic brain injury

The response of the developing brain to traumatic injury is different from the response of the mature, adult brain. There are critical developmental trajectories in the young brain, whereby injury can lead to long term functional abnormalities. Emerging preclinical and clinical literature supports the presence of significant sex differences in both the response to and the recovery from pediatric traumatic brain injury (TBI). These sex differences are seen at all pediatric ages, including neonates/infants, pre-pubertal children, and adolescents. As importantly, the response to neuroprotective therapies or treatments can differ between male and females subjects. These sex differences can result from several biologic origins, and may manifest differently during the various phases of brain and body development. Recognizing and understanding these potential sex differences is crucial, and should be considered in both preclinical and clinical studies of pediatric TBI.

Isoliquiritigenin Attenuates Neuroinflammation in Traumatic Brain Injury in Young Rats

OBJECTIVES

Inflammation and apoptosis play a critical role in the pathological progress of traumatic brain injury (TBI). Isoliquiritigenin is a bioactive component extracted from licorice roots, which possesses anti-inflammatory and anti-apoptotic properties. This study aims to investigate the potential effects of isoliquiritigenin on neuroinflammation in a rat model of TBI.

METHODS

The SH-SY5Y cells were subjected to cell injury induced by shear stress and the effect of isoliquiritigenin on cell apoptosis was measured. Male rats received a controlled cortical impact to induce TBI and were then treated with isoliquiritigenin (20 mg/kg). Brain edema and contusion volume were measured to assess brain damage. Morris water maze, the beam-balance test, and the beam-walk test were performed to evaluate the cognitive and motor functions.

RESULTS

Levels of proinflammatory cytokines and apoptotic regulators were measured. Results showed that isoliquiritigenin reduced shear stress-induced cell apoptosis in vitro. In young rats subjected to TBI, treatment of isoliquiritigenin reduced brain damage and attenuated motor and cognitive impairments. Isoliquiritigenin also reduced the level of proinflammatory cytokines and Bax and increased Bcl-2 and Bcl-xL in TBI rats.

CONCLUSIONS

These findings suggest that isoliquiritigenin possesses beneficial effects in TBI by inhibiting inflammation and apoptosis.

A mathematical model of neuroinflammation in severe clinical traumatic brain injury

Background

Understanding the interdependencies among inflammatory mediators of tissue damage following traumatic brain injury (TBI) is essential in providing effective, patient-specific care. Activated microglia and elevated concentrations of inflammatory signaling molecules reflect the complex cascades associated with acute neuroinflammation and are predictive of recovery after TBI. However, clinical TBI studies to date have not focused on modeling the dynamic temporal patterns of simultaneously evolving inflammatory mediators, which has potential in guiding the design of future immunomodulation intervention studies.

Methods

We derived a mathematical model consisting of ordinary differential equations (ODE) to represent interactions between pro- and anti-inflammatory cytokines, M1- and M2-like microglia, and central nervous system (CNS) tissue damage. We incorporated variables for several cytokines, interleukin (IL)-1β, IL-4, IL-10, and IL-12, known to have roles in microglial activation and phenotype differentiation. The model was fit to cerebrospinal fluid (CSF) cytokine data, collected during the first 5 days post-injury in n = 89 adults with severe TBI. Ensembles of model fits were produced for three patient subgroups: (1) a favorable outcome group (GOS = 4,5) and (2) an unfavorable outcome group (GOS = 1,2,3) both with lower pro-inflammatory load, and (3) an unfavorable outcome group (GOS = 1,2,3) with higher pro-inflammatory load. Differences in parameter distributions between subgroups were ranked using Bhattacharyya metrics to identify mechanistic differences underlying the neuroinflammatory patterns of patient groups with different TBI outcomes.

Results

Optimal model fits to data showed different microglial and damage responses by patient subgroup. Upon comparison of model parameter distributions, unfavorable outcome groups were characterized by either a prolonged, pathophysiological or a transient, sub-physiological course of neuroinflammation.

Conclusion

By developing a mathematical characterization of inflammatory processes informed by clinical data, we have created a system for exploring links between acute neuroinflammatory components and patient outcome in severe TBI.

Electronic supplementary material

The online version of this article (10.1186/s12974-018-1384-1) contains supplementary material, which is available to authorized users.

Significant changes in circular RNA in the mouse cerebral cortex around an injury site after traumatic brain injury

BACKGROUND AND OBJECTIVE

Circular RNA (circRNA) is an important type of non-coding RNA that has not been widely researched in traumatic brain injury (TBI). The present study aimd to detect the altered circRNA expression around an injury site in the mouse cerebral cortex after TBI and explore its potential functions.

METHOD

C57BL/6 mice were used to construct a controlled cortical impact (CCI) model to simulate TBI. At 24 h post-TBI, the cortex around the injury site was collected, and the total RNA was extracted to perform RNA sequencing (RNA-seq). The differentially expressed circRNAs were determined according to the following criteria: |log₂^{(fold change)}| > 1, P < .05 and FDR < 0.05. Among them, circRNA chr8_87,859,283-87,904,548 was preliminarily explored to determine its function.

RESULTS

A total of 8036 altered circRNAs were discovered, and among them, 16 were significantly changed (5 up-regulated and 11 down-regulated). The circRNA chr8_87,859,283-87,904,548 significantly increased by approximately 4 times in the cerebral cortex around the injury site after TBI and promoted neuro-inflammation through increasing the CXCR2 protein by sponging mmu-let-7a-5p. As a result, the increased circRNA chr8_87,859,283-87,904,548 blocked the restoration of neurological function after TBI.

CONCLUSION

Many circRNAs are significantly up-regulated or down-regulated in the traumatic cerebral penumbra cortex after TBI. Among them, the circRNA chr8_87,859,283-87,904,548 potentially plays a pro-inflammatory role, which may have a deleterious effect on neurological restoration after TBI. .

Protein biomarkers of epileptogenicity after traumatic brain injury

Traumatic brain injury (TBI) is a major risk factor for acquired epilepsy. Post-traumatic epilepsy (PTE) develops over time in up to 50% of patients with severe TBI. PTE is mostly unresponsive to traditional anti-seizure treatments suggesting distinct, injury-induced pathomechanisms in the development of this condition. Moderate and severe TBIs cause significant tissue damage, bleeding, neuron and glia death, as well as axonal, vascular, and metabolic abnormalities. These changes trigger a complex biological response aimed at curtailing the physical damage and restoring homeostasis and functionality. Although a positive correlation exists between the type and severity of TBI and PTE, there is only an incomplete understanding of the time-dependent sequelae of TBI pathobiologies and their role in epileptogenesis. Determining the temporal profile of protein biomarkers in the blood (serum or plasma) and cerebrospinal fluid (CSF) can help to identify pathobiologies underlying the development of PTE, high-risk individuals, and disease modifying therapies. Here we review the pathobiological sequelae of TBI in the context of blood- and CSF-based protein biomarkers, their potential role in epileptogenesis, and discuss future directions aimed at improving the diagnosis and treatment of PTE.

Current understanding of neuroinflammation after traumatic brain injury and cell-based therapeutic opportunities

Traumatic brain injury (TBI) remains a major cause of death and disability worldwide. Increasing evidence indicates that TBI is an important risk factor for neurodegenerative diseases including Alzheimer's disease, Parkinson's disease, and chronic traumatic encephalopathy. Despite improved supportive and rehabilitative care of TBI patients, unfortunately, all late phase clinical trials in TBI have yet to yield a safe and effective neuroprotective treatment. The disappointing clinical trials may be attributed to variability in treatment approaches and heterogeneity of the population of TBI patients as well as a race against time to prevent or reduce inexorable cell death. TBI is not just an acute event but a chronic disease. Among many mechanisms involved in secondary injury after TBI, emerging preclinical studies indicate that posttraumatic prolonged and progressive neuroinflammation is associated with neurodegeneration which may be treatable long after the initiating brain injury. This review provides an overview of recent understanding of neuroinflammation in TBI and preclinical cell-based therapies that target neuroinflammation and promote functional recovery after TBI.

Autologous white blood cell infusion for trauma, brain trauma, stroke and select immune dysfunction co-morbidities: A promising and timely proposal?

All traumas suppress the immune system, resulting in higher morbidity and mortality. Infections, poor nutritional status, chronic illness, fatigue, therapies or procedures performed during and after transport also negatively affect the immune system. Large populations are impacted by trauma worldwide and suffer enormous costs in both direct and indirect expenditures from physical, psychological and functional losses. Most therapies and studies of trauma, brain trauma, stroke, immune suppression and their co-morbidities do not address nor discuss methods that promote immune system resuscitation or efficacy to support its role in post-trauma healing and rehabilitation. These omissions present an opportunity for using autologous stored naïve (unexposed to the current trauma and co-morbidities) white blood cell infusions (autologous white blood cell infusion) (AWBCI) to supplement treatment of most traumas, trauma-associated infections, other co-morbidities and immune suppression derived problems in order to improve the global standard of trauma care. We hypothesize to give the traumatized patients back their own immune system that has been 'stored' in some fashion, either cryogenically or just after or during the trauma event [surgery, etc for example]. We emphasize that other treatments should not be replaced - rather we suggest AWBCI as concurrent therapy. We present focused select animal and human studies as proofs of concept to arrive at and support our therapeutic suggestion and hypotheses, flowing historically from donor white blood cell therapy [DLI] to close cohort white blood cell therapy to autologous white blood cell infusion [AWBCI]. We integrate the concept of personalized medicine from an evidence-based framework while maintaining scientific rigor and statistical proof as a basis of our hypotheses.

Analysis of selected pro- and anti-inflammatory cytokines in patients with multiple injuries in the early period after trauma

Introduction

Severe trauma causes damage to the protective barriers of the organism, and thus activates immunological reaction. Among substances secreted during this process pro-inflammatory cytokines are of high importance.

The aim of the study

Severe trauma causing multiple injuries is more likely to lead to particularly intensive inflammatory reaction, which can sometimes lead to serious complications, even life-threatening. The aim of the study is to determine those parameters which may serve as predictors of infectious complications and to enable estimation of the patient's immunological status before the decision to introduce elective procedures.

Material and methods

The study population included patients with multiple trauma treated in the Department of Trauma Surgery of the Medical University of Gdańsk. The severity of injuries was evaluated with commonly used numerical scales (Revised Trauma Score - RTS, Injury Severity Score - ISS, Glasgow Coma Scale - GCS). Blood samples were collected on the first, second, and fifth day after injury. Evaluated parameters: C-reactive protein (CRP), the level of cytokines: IL-8, IL-1β, IL-6, TNF, IL-12p70, and IL-10. Control population: individuals without injury.

Results

Evaluation of IL-6, IL-8, and CRP levels in patients with multiple trauma in the early period after injury (2-3 days) could be considered as a predictor of delayed infection (5-10 days). CRP level, being cheap and commonly accessible, can be used in clinical practice enabling identification of patients at higher risk of infectious complications and introduction of appropriate treatment and prevention. The analysis of the mentioned parameters may contribute to choosing an appropriate management strategy, including "timing" depending on the patient's biological status.