Systemic inflammation activates coagulation and immune cell infiltration pathways in brains with propagating α-synuclein fibril aggregates

Synucleinopathies are a group of diseases characterized by brain aggregates of α-synuclein (α-syn). The gradual accumulation of α-syn and the role of inflammation in early-stage pathogenesis remain poorly understood. We explored this interaction by inducing chronic inflammation in a common pre-clinical synucleinopathy mouse model. Three weeks post unilateral intra-striatal injections of human α-syn pre-formed fibrils (PFF), mice underwent repeated intraperitoneal injections of 1 mg/ml lipopolysaccharide (LPS) for 3 weeks. Histological examinations of the ipsilateral site showed phospho-α-syn regional spread and LPS-induced neutrophil recruitment to the brain vasculature. Biochemical assessment of the contralateral site confirmed spreading of α-syn aggregation to frontal cortex and a rise in intracerebral TNF-α, IL-1β, IL-10 and KC/GRO cytokines levels due to LPS. No LPS-induced exacerbation of α-syn pathology load was observed at this stage. Proteomic analysis was performed contralateral to the PFF injection site using LC-MS/MS. Subsequent downstream Reactome Gene-Set Analysis indicated that α-syn pathology alters mitochondrial metabolism and synaptic signaling. Chronic LPS-induced inflammation further lead to an overrepresentation of pathways related to fibrin clotting as well as integrin and B cell receptor signaling. Western blotting confirmed a PFF-induced increase in fibrinogen brain levels and a PFF + LPS increase in Iba1 levels, indicating activated microglia. Splenocyte profiling revealed changes in T and B cells, monocytes, and neutrophils populations due to LPS treatment in PFF injected animals. In summary, early α-syn pathology impacts energy homeostasis pathways, synaptic signaling and brain fibrinogen levels. Concurrent mild systemic inflammation may prime brain immune pathways in interaction with peripheral immunity.

Surgical stress response in robot-assisted versus laparoscopic surgery for colon cancer (SIRIRALS): randomized clinical trial

BACKGROUND

Evidence for the routine use of robotic technology and its impact on short-term outcomes in colon cancer surgery is lacking. The aim of this study was to compare the surgically induced systemic stress response and clinical and patient-reported outcomes for patients undergoing robot-assisted or laparoscopic colon cancer surgery.

METHODS

In this double-blinded superiority RCT completed between August 2021 and March 2023, patients with stage 1-3 colon cancer were randomized in a 1 : 1 ratio to undergo either robot-assisted or laparoscopic colon cancer surgery. The primary outcome was changes in the systemic stress response, characterized by C-reactive protein expression in the first three postoperative days. Secondary outcomes were intraoperative and postoperative complications and patient-reported outcomes. The latter included quality of recovery-15 and pain intensity using a visual analogue scale.

RESULTS

In total, 128 patients were screened for potential inclusion in this study; 50 patients (25 in the robot-assisted group and 25 in the laparoscopic group) were included in the final follow-up and analysis. The postoperative C-reactive protein response was higher on the first postoperative day in the laparoscopic group (mean difference = 19.88 mg/l, 95% c.i. 3.89-35.86; P = 0.045). No statistically significant differences were noted for C-reactive protein expression on the second and third postoperative days.

CONCLUSION

Adopting robot-assisted surgery for stage 1-3 colon cancer is associated with a reduction in the surgical stress response.

REGISTRATION NUMBER

NCT04687384 (http://www.clinicaltrials.gov).

Performance Measures and Plasma Biomarker Levels in Patients with Multiple Sclerosis after 14 Days of Fampridine Treatment: An Explorative Study

Peripheral cytokine levels may serve as biomarkers for treatment response and disease monitoring in patients with multiple sclerosis (pwMS). The objectives were to assess changes in plasma biomarkers in PwMS after 14 days of fampridine treatment and to explore correlations between changes in performance measures and plasma biomarkers. We included 27 PwMS, 14 women and 13 men, aged 52.0 ± 11.6 years, with a disease duration of 17 ± 8.5 years, and an Expanded Disability Status Scale of 6 [IQR 5.0/6.5]. Gait and hand function were assessed using performance tests completed prior to fampridine and after 14 days of treatment. Venous blood was obtained, and chemiluminescence analysis conducted to assess plasma cytokines and neurodegenerative markers. All performance measures demonstrated improvements. Biomarkers showed decreased tumor necrosis factor (TNF) receptor-2 levels. Associations were found between change scores in (i) Six Spot Step Test and Interleukin (IL)-2, IL-8, and IL-17 levels; (ii) timed 25-foot walk and interferon-γ, IL-2, IL-8, TNF-α, and neurofilament light levels, and (iii) 12-Item Multiple Sclerosis Walking Scale and IL-17 levels. The associations may reflect increased MS-related inflammatory activity rather than a fampridine-induced response or that a higher level of inflammation induces a better response to fampridine.

Microglia-Derived Insulin-like Growth Factor 1 Is Critical for Neurodevelopment

Insulin-like growth factor 1 (IGF-1) is a peptide hormone essential for the proper development and growth of the organism, as a complete knockout of Igf1 in mice is lethal, causing microcephaly, growth retardation and the defective development of organs. In the central nervous system, neurons and glia have been reported to express Igf1, but their relative importance for postnatal development has not yet been fully defined. In order to address this, here, we obtained mice with a microglia-specific inducible conditional knockout of Igf1. We show that the deficiency in microglial Igf1, starting in the first postnatal week, leads to body and brain growth retardation, severely impaired myelination, changes in microglia numbers, and behavioral abnormalities. These results emphasize the importance of microglial-derived Igf1 for brain development and function and open new perspectives for the investigation of the role of microglial-Igf1 in neurological diseases.

Systemic treatment with a selective TNFR2 agonist alters the central and peripheral immune responses and transiently improves functional outcome after experimental ischemic stroke

Ischemic stroke often leaves survivors with permanent disabilities and therapies aimed at limiting detrimental inflammation and improving functional outcome are still needed. Tumor necrosis factor (TNF) levels increase rapidly after ischemic stroke, and while signaling through TNF receptor 1 (TNFR1) is primarily detrimental, TNFR2 signaling mainly has protective functions. We therefore investigated how systemic stimulation of TNFR2 with the TNFR2 agonist NewSTAR2 affects ischemic stroke in mice. We found that NewSTAR2 treatment induced changes in peripheral immune cell numbers and transiently affected microglial numbers and neuroinflammation. However, this was not sufficient to improve long-term functional outcome after stroke in mice.

Peripherally derived myeloid cells induce disease-dependent phenotypic changes in microglia

In central nervous system (CNS) injury and disease, peripherally derived myeloid cells infiltrate the CNS parenchyma and interact with resident cells, propagating the neuroinflammatory response. Because peripheral myeloid populations differ profoundly depending on the type and phase of injury, their crosstalk with CNS resident cells, particularly microglia, will lead to different functional outcomes. Thus, understanding how peripheral myeloid cells affect the phenotype and function of microglia in different disease conditions and phases may lead to a better understanding of disease-specific targetable pathways for neuroprotection and neurorepair. To this end, we set out to develop an in vitro system to investigate the communication between peripheral myeloid cells and microglia, with the goal of uncovering potential differences due to disease type and timing. We isolated peripheral myeloid cells from mice undergoing experimental autoimmune encephalomyelitis (EAE), a model of multiple sclerosis, or acute cerebral ischemia by permanent middle cerebral artery occlusion (pMCAO) at different times after disease and probed their ability to change the phenotype of primary microglia isolated from the brain of adult mice. We identified changes not only dependent on the disease model, but also on the timepoint after disease onset from which the myeloid cells were isolated. Peripheral myeloid cells from acute EAE induced morphological changes in microglia, followed by increases in expression of genes involved in inflammatory signaling. Conversely, it was the peripheral myeloid cells from the chronic phase of pMCAO that induced gene expression changes in genes involved in inflammatory signaling and phagocytosis, which was not followed by a change in morphology. This underscores the importance of understanding the role of infiltrating myeloid cells in different disease contexts and phases. Furthermore, we showed that our assay is a valuable tool for investigating myeloid cell interactions in a range of CNS neuroinflammatory conditions.

USP25 Inhibits Neuroinflammatory Responses After Cerebral Ischemic Stroke by Deubiquitinating TAB2

Cerebral ischemic stroke is a leading cause of morbidity and mortality globally. However, the mechanisms underlying ischemic stroke injury remain poorly understood. Here, it is found that deficiency of the ubiquitin-specific protease USP25 significantly aggravate ischemic stroke injury in mice. USP25 has no impact on neuronal death under hypoxic conditions, but reduced ischemic stroke-induced neuronal loss and neurological deficits by inhibiting microglia-mediated neuroinflammation. Mechanistically, USP25 restricts the activation of NF-κB and MAPK signaling by regulating TAB2. As a deubiquitinating enzyme, USP25 removeds K63-specific polyubiquitin chains from TAB2. AAV9-mediated TAB2 knockdown ameliorates ischemic stroke injury and abolishes the effect of USP25 deletion. In both mouse and human brains, USP25 is markedly upregulated in microglia in the ischemic penumbra, implying a clinical relevance of USP25 in ischemic stroke. Collectively, USP25 is identified as a critical inhibitor of ischemic stroke injury and this data suggest USP25 may serve as a therapeutic target for ischemic stroke.

The Danish Pain Research Biobank (DANPAIN-Biobank): a collection of blood, cerebrospinal fluid, and clinical data for the study of neuroimmune and glia-related biomarkers of chronic pain

Background

Chronic pain is a major health problem worldwide but the limited knowledge of its underlying pathophysiology impairs the opportunities for diagnostics and treatment. Biomarkers of chronic pain are greatly needed to understand the disease and develop new targets for interventions and drug treatments, and potentially introduce more precise diagnostic procedures. Much evidence points to a neuroimmune pathology for many chronic pain conditions and that important neuroimmune biomarkers exist in the cerebrospinal fluid (CSF) of patients with chronic pain. Systematic collection of CSF in large cohorts of chronic pain patients and healthy volunteers has proven difficult, however. We established the Danish Pain Research Biobank (DANPAIN-Biobank) with the aim of studying potential neuroimmune and glia-related biomarkers of chronic pain. In this paper, we describe the methods and the study population of the DANPAIN-Biobank.

Methods

In this cross-sectional study, we included (I) participants with high-impact (HI) chronic pain from a tertiary, interdisciplinary pain center; (II) participants with osteoarthritic pain scheduled for arthroplasty surgery of the hip or knee at a regional hospital; and (III) pain-free volunteers. All participants completed a questionnaire assessing pain, functional impairment, anxiety, depression, and insomnia before samples of blood and CSF were extracted. Quantitative sensory tests were performed on participants with HI chronic pain and pain-free volunteers, and postoperative outcome scores were available on participants with osteoarthritic pain.

Results

Of the 352 participants included, 201 had HI chronic pain (of which 71% had chronic widespread pain), 81 had chronic osteoarthritic pain, and 70 were pain-free volunteers. Samples were handled uniformly, and CSF samples were frozen within 30 minutes.

Conclusions

We describe the content of the DANPAIN-Biobank, which is unique in terms of the number of participants (including pain-free volunteers), extensive clinical data, and uniformity in sample handling. We believe it presents a promising new platform for the study of neuroimmune and glia-related biomarkers of chronic pain.

Distinct myeloid population phenotypes dependent on TREM2 expression levels shape the pathology of traumatic versus demyelinating CNS disorders

Triggering receptor expressed on myeloid cell 2 (TREM2) signaling often drives opposing effects in traumatic versus demyelinating CNS disorders. Here, we identify two distinct phenotypes of microglia and infiltrating myeloid populations dependent on TREM2 expression levels at the acute stage and elucidate how they mediate the opposing effects of TREM2 in spinal cord injury (SCI) versus multiple sclerosis animal models (experimental autoimmune encephalomyelitis [EAE]). High TREM2 levels sustain phagocytic microglia and infiltrating macrophages after SCI. In contrast, moderate TREM2 levels sustain immunomodulatory microglia and infiltrating monocytes in EAE. TREM2-ablated microglia (purine-sensing phenotype in SCI and reduced immunomodulatory phenotype in EAE) drive transient protection at the acute stage of both disorders, whereas reduced phagocytic macrophages and lysosome-activated monocytes lead to contrasting neuroprotective and demyelinating effects in SCI versus EAE, respectively. Our study provides comprehensive insights into the complex roles of TREM2 in myeloid populations across diverse CNS disorders, which has crucial implications in devising TREM2-targeting therapeutics.

Selective Inhibition of Soluble Tumor Necrosis Factor Alters the Neuroinflammatory Response following Moderate Spinal Cord Injury in Mice

Clinical and animal model studies have implicated inflammation and glial and peripheral immune cell responses in the pathophysiology of spinal cord injury (SCI). A key player in the inflammatory response after SCI is the pleiotropic cytokine tumor necrosis factor (TNF), which exists both in both a transmembrane (tmTNF) and a soluble (solTNF) form. In the present study, we extend our previous findings of a therapeutic effect of topically blocking solTNF signaling after SCI for three consecutive days on lesion size and functional outcome to study the effect on spatio-temporal changes in the inflammatory response after SCI in mice treated with the selective solTNF inhibitor XPro1595 and compared to saline-treated mice. We found that despite comparable TNF and TNF receptor levels between XPro1595- and saline-treated mice, XPro1595 transiently decreased pro-inflammatory interleukin (IL)-1β and IL-6 levels and increased pro-regenerative IL-10 levels in the acute phase after SCI. This was complemented by a decrease in the number of infiltrated leukocytes (macrophages and neutrophils) in the lesioned area of the spinal cord and an increase in the number of microglia in the peri-lesion area 14 days after SCI, followed by a decrease in microglial activation in the peri-lesion area 21 days after SCI. This translated into increased myelin preservation and improved functional outcomes in XPro1595-treated mice 35 days after SCI. Collectively, our data suggest that selective targeting of solTNF time-dependently modulates the neuroinflammatory response by favoring a pro-regenerative environment in the lesioned spinal cord, leading to improved functional outcomes.

Monocyte secretory profiling in a clinical and MEFV genotype-characterized cohort of Danish familial Mediterranean fever patients: diagnostic potential of CCL1 and CXCL1

OBJECTIVE

The autoinflammatory disease familial Mediterranean fever (FMF), characterized by recurrent attacks of sterile fever, serosal, and/or synovial inflammation, is caused by variants in the Mediterranean fever gene, MEFV, coding for the pyrin inflammasome sensor. The diagnosis of FMF is mainly based on clinical symptoms and confirmed by detection of disease-associated MEFV variants. However, the diagnosis is challenging among patients carrying variants of uncertain clinical significance (VUS). In this study, we aimed to identify potential FMF discriminatory diagnostic markers in a cohort of clinically characterized FMF patients.

METHOD

We established a cohort of clinically and MEFV genotype-characterized FMF patients by enrolling patients from major Danish hospitals (n = 91). The secretory profile of pyrin inflammasome-activated monocytes from healthy donors (HDs) and MEFV-characterized FMF patients (n = 28) was assessed by analysing cell supernatants for a custom-designed panel of 23 cytokines, chemokines, and soluble tumour necrosis factor receptors associated with monocyte and macrophage function.

RESULTS

MEFV genotypes in Danish FMF patients were associated with age at symptom onset (p < 0.05), FMF among relatives (p < 0.01), proportion of patients in colchicine treatment (p < 0.01), and treatment response (p < 0.05). Secretion of chemokines CCL1 and CXCL1 from pyrin-activated FMF monocytes was significantly decreased compared to HDs (p < 0.05), and could discriminate FMF patients with 'non-confirmatory' MEFV genotypes from HDs with 80.0% and 70.0% sensitivity for CCL1 and CXCL1, respectively (p < 0.05).

CONCLUSION

Our data suggest that a functional diagnostic assay based on CCL1 or CXCL1 levels in pyrin-activated patient monocytes may contribute to FMF diagnosis in patients with VUS.

Criterion validity of muscle strain analyses of skeletal muscle function in patients with multiple sclerosis

BACKGROUND

Despite the wide range of existing performance measures to evaluate functional status of patients with multiple sclerosis, the heterogeneous nature of the disease hinders clinical characterization and monitoring of disease severity. Speckle tracking ultrasonography is a non-invasive technique to assess isolated muscle function by evaluating the contractile properties of muscle tissue, i.e. muscle strain. The aim of this study was to investigate whether muscle strain measured by speckle tracking ultrasonography could be a useful quantitative measure of muscle function in patients with multiple sclerosis. The criterion validity of muscle strain was compared to that of validated performance measures of upper and lower extremity function.

METHODS

This cross-sectional study used baseline data from an explorative observational cohort study (the MUST study). Participants recruited from a hospital outpatient MS clinic underwent speckle tracking ultrasonography of the biceps brachii, supraspinatus, and soleus muscles of the dominant side according to pre-defined submaximal isometric contractions. Participants also completed the Timed 25-Foot Walk Test, the Six Spot Step Test, the 2-minute walking test, the Nine-Hole Peg Test, the 12-item Multiple Sclerosis Walking Scale, and the Oxford Shoulder Score. Gaussian distribution was investigated by visual inspection of normal probability plots and the Shapiro-Wilk test. The Timed 25-Foot Walk Test and Nine-Hole Peg Test were selected as gold standards for function of the lower and upper extremities, respectively. Criterion validity was assessed using Spearman's rank-order correlation coefficient ρ (rho), comparing the muscle strain and performance measures against predefined gold standards. Differences in criterion validity were estimated using squared correlations on the Fischer's Z-scale, with non-parametric bootstrapping to obtain bias-corrected, accelerated bootstrap confidence intervals (95% BCa).

RESULTS

Criterion validity showed good to excellent correlations between the gold standard for lower extremity function and the 2-minute walking test and Six Spot Step Test, and a fair correlation to the 12-item Multiple Sclerosis Walking Scale. No significant correlation was found between the gold standard for upper extremity function and the performance measure. There were no significant correlations between the gold standards and muscle strain.

CONCLUSION

The absence of criterion validity for muscle strain alongside fair to strong criterion validity for the performance measures indicates that speckle tracking ultrasonography assessment of muscle strain is either invalid or evaluates other constructs of multiple sclerosis. Muscle strain assessed by speckle tracking ultrasonography cannot be recommended for the evaluation of treatment effects or disease progression in multiple sclerosis.

Gait quality and function after fampridine treatment in patients with multiple sclerosis - A prospective cohort study

BACKGROUND

Fampridine has shown to improve walking speed, motor control, and balance in patients with multiple sclerosis. However, potential fampridine-induced changes in gait quality and underlying mechanisms, evaluated by three-dimensional gait analysis, are poorly examined. The aim was to examine if two weeks of fampridine treatment would improve gait quality (using Gait Profile Score and Gait Variable Scores from three-dimensional gait analysis) and gait function (using performance-based tests, spatiotemporal parameters, and self-perceived gait function).

METHODS

14 participants with multiple sclerosis were included (9 women and 5 men, age 53.6 ± 12.8 years, disease duration 21 ± 9.1 years) in this cohort study. Tests were completed prior to fampridine and after 14 (± 1) days of treatment. Three-dimensional gait analyses were completed, and kinematic measures were calculated for overall gait quality using Gait Profile Score, and for joint-specific variables, Gait Variable Scores. Gait function was assessed using spatiotemporal parameters, performance-based tests, and a patient-reported outcome measure. Student's paired t-test/Wilcoxon signed rank test were used to compare baseline and follow-up variables. Sample size calculation for Gait Profile Score required at least 9 participants.

FINDINGS

No fampridine-induced improvements in gait quality were demonstrated. For gait function, improvements were found in performance-based tests (Timed 25-Foot Walk: -11.5%; Six Spot Step Test: -13.9%; 2-Minute Walk Test: 18.2%) and self-perceived gait function (12-itemMS Walking Scale: -35.2%).

INTERPRETATION

Although two weeks of fampridine treatment in patients with multiple sclerosis improved gait function, there was no change in overall kinematic quality of gait.

TRIAL REGISTRATION

This work was collected as a part of a registered clinical trial (MUST): ClinicalTrials.govNCT03847545.

Disturbed microcirculation and hyperaemic response in a murine model of systemic inflammation

Systemic inflammation affects cognitive functions and increases the risk of dementia. This phenomenon is thought to be mediated in part by cytokines that promote neuronal survival, but the continuous exposure to which may lead to neurodegeneration. The effects of systemic inflammation on cerebral blood vessels, and their provision of adequate oxygen to support critical brain parenchymal cell functions, remains unclear. Here, we demonstrate that neurovascular coupling is profoundly disturbed in lipopolysaccharide (LPS) induced systemic inflammation in awake mice. In the 24 hours following LPS injection, the hyperaemic response of pial vessels to functional activation was attenuated and delayed. Concurrently, under steady-state conditions, the capillary network displayed a significant increase in the number of capillaries with blocked blood flow, as well as increased duration of 'capillary stalls'-a phenomenon previously reported in animal models of stroke and Alzheimer's disease pathology. We speculate that vascular changes and impaired oxygen availability may affect brain functions following acute systemic inflammation and contribute to the long-term risk of neurodegenerative changes associated with chronic, systemic inflammation.

Selective inhibition of soluble tumor necrosis factor signaling reduces abdominal aortic aneurysm progression

Background

Tumor necrosis factor (TNF) is pathologically elevated in human abdominal aortic aneurysms (AAA). Non-selective TNF inhibition-based therapeutics are approved for human use but have been linked to several side effects. Compounds that target the proinflammatory soluble form of TNF (solTNF) but preserve the immunomodulatory capabilities of the transmembrane form of TNF (tmTNF) may prevent these side effects. We hypothesize that inhibition of solTNF signaling prevents AAA expansion.

Methods

The effect of the selective solTNF inhibitor, XPro1595, and the non-selective TNF inhibitor, Etanercept (ETN) was examined in porcine pancreatic elastase (PPE) induced AAA mice, and findings with XPro1595 was confirmed in angiotensin II (ANGII) induced AAA in hyperlipidemic apolipoprotein E (Apoe) ^–/– mice.

Results

XPro1595 treatment significantly reduced AAA expansion in both models, and a similar trend (p = 0.06) was observed in PPE-induced AAA in ETN-treated mice. In the PPE aneurysm wall, XPro1595 improved elastin integrity scores. In aneurysms, mean TNFR1 levels reduced non-significantly (p = 0.07) by 50% after TNF inhibition, but the histological location in murine AAAs was unaffected and similar to that in human AAAs. Semi-quantification of infiltrating leucocytes, macrophages, T-cells, and neutrophils in the aneurysm wall were unaffected by TNF inhibition. XPro1595 increased systemic TNF levels, while ETN increased systemic IL-10 levels. In ANGII-induced AAA mice, XPro1595 increased systemic TNF and IL-5 levels. In early AAA development, proteomic analyses revealed that XPro1595 significantly upregulated ontology terms including “platelet aggregation” and “coagulation” related to the fibrinogen complex, from which several proteins were among the top regulated proteins. Downregulated ontology terms were associated with metabolic processes.

Conclusion

In conclusion, selective inhibition of solTNF signaling reduced aneurysm expansion in mice, supporting its potential as an attractive treatment option for AAA patients.

Early-stage inflammation changes in supraspinatus muscle after rotator cuff tear

BACKGROUND

Rotator cuff (RC) tendon tear leads to impaired shoulder function and pain. The supraspinatus (SS) tendon is most often affected, but the biological response of the SS muscle to SS tendon tear is largely unknown. This study aimed to investigate time-dependent muscle inflammation, degeneration, fatty infiltration, and regeneration in experimental SS tear conditions.

METHODS

Forty-five C57BL/6 mice were subjected to SS tendon tear and allowed to recover for 1, 3, 5, 7, 14, or 28 days. The extent of muscle damage was examined using histologic, flow cytometric, proteomic, and chemiluminescence analyses.

RESULTS

We found that muscle inflammation peaked around day 5 with increased monocyte infiltration and increased cytokine levels in the ipsilateral compared to the contralateral SS muscle. Bioinformatics analysis of proteomics on mice that survived 5 days after RC tendon tear revealed upregulated proteins involved in "neutrophil activation involved in immune response" and "extracellular matrix organization," whereas "skeletal muscle tissue development and contraction" and "respiratory electron transport chain" were among the most downregulated. Histologic analysis of collagen showed increased collagen accumulation and fatty infiltration of the ipsilateral SS over time. Finally, we observed time- and lesion-dependent changes in satellite cell and fibro-adipogenic progenitor populations.

CONCLUSION

Altogether, we demonstrate that the SS muscle shows severe signs of acute inflammation, early degeneration, and fatty infiltration, as well as reduced regenerative potential following SS tendon tear.

Biomarkers in asthma in the context of atopic dermatitis in young children

BACKGROUND

Diverse pathways stemming from a history of atopic dermatitis (AD) might modulate different biomarkers associated with the development of asthma. Biomarkers associated with AD and asthma separately have been investigated, but none have characterized a combined AD+asthma phenotype. We investigated the clinical and molecular characteristics associated with an AD+asthma phenotype compared with AD, asthma and controls.

METHODS

From a prospective birth cohort and the outpatient allergy clinic, we included four groups of 6-12-year-old children: (1) healthy controls (2) previous, current, or present AD without asthma, (3) previous, current, or present AD and current asthma and (4) current asthma without AD. We performed clinical examinations and interviews and measured serum IgE, natural moisturizing factors (NMF), and plasma cytokine levels.

RESULTS

We found an increased number of IgE sensitizations in AD+asthma, prominent after stratifying for food allergens (p < .05). Pro-Th₂ cytokines CCL18, TSLP, and Eotaxin-3 were elevated in AD+asthma, though not significantly higher than asthma, and elevated in asthma compared with controls. NMF levels were decreased in AD compared with asthma and control groups (p = .019, p < .001, respectively). NMF levels correlated negatively to sensitization (p = .026), though nonsignificant with only the patient groups.

CONCLUSION

Our results indicate that Th₂ cytokines and increased number of sensitizations are associated with AD + asthma phenotypes compared with AD alone and that skin barrier impairment as well as decreased airway epithelial integrity may play a role in sensitization and immune modulation. Our findings suggest candidate biomarkers that should be further explored for their functional roles and prognostic potential.

Interleukin-1 Mediates Ischemic Brain Injury via Induction of IL-17A in γδ T Cells and CXCL1 in Astrocytes

As a prototypical proinflammatory cytokine, interleukin-1 (IL-1) exacerbates the early post-stroke inflammation, whereas its neutralization is protective. To further investigate the underlying cell-type-specific IL-1 effects, we subjected IL-1 (α/β) knockout (Il1^−/−) and wildtype (WT) littermate mice to permanent middle cerebral artery occlusion (pMCAO) and assessed immune cell infiltration and cytokine production in the ischemic hemisphere by flow cytometry 24 h and 72 h after stroke. Il1^−/− mice showed smaller infarcts and reduced neutrophil infiltration into the ischemic brain. We identified γδ T cells and astrocytes as target cells of IL-1 signaling-mediated neutrophil recruitment. First, IL-1-induced IL-17A production in γδ T cells in vivo, and IL-17A enhanced the expression of the main neutrophil attracting chemokine CXCL1 by astrocytes in the presence of tumor necrosis factor (TNF) in vitro. Second, IL-1 itself was a potent activator of astrocytic CXCL1 production in vitro. By employing a novel FACS sorting strategy for the acute isolation of astrocytes from ischemic brains, we confirmed that IL-1 is pivotal for Cxcl1 upregulation in astrocytes in vivo. Our results underscore the pleiotropic effects of IL-1 on immune and non-immune cells within the CNS to mount and amplify the post-stroke inflammatory response.

Efficacy of Chronic Paroxetine Treatment in Mitigating Amyloid Pathology and Microgliosis in APPSWE/PS1ΔE9 Transgenic Mice

BACKGROUND

Modulation of serotonergic signaling by treatment with selective serotonin reuptake inhibitors (SSRIs) has been suggested to mitigate amyloid-β (Aβ) pathology in Alzheimer's disease, in addition to exerting an anti-depressant action.

OBJECTIVE

To investigate the efficacy of chronic treatment with the SSRI paroxetine, in mitigating Aβ pathology and Aβ plaque-induced microgliosis in the hippocampus of 18-month-old APPswe/PS1 ΔE9 mice.

METHODS

Plaque-bearing APPswe/PS1 ΔE9 and wildtype mice were treated with paroxetine per os at a dose of 5 mg/kg/day, from 9 to 18 months of age. The per os treatment was monitored by recording of the body weights and serum paroxetine concentrations, and by assessment of the serotonin transporter occupancy by [3H]DASB-binding in wildtype mice. Additionally, 5,7-dihydroxytryptamine was administered to 9-month-old APPswe/PS1 ΔE9 mice, to examine the effect of serotonin depletion on Aβ pathology. Aβ pathology was evaluated by Aβ plaque load estimation and the Aβ 42/Aβ 40 ratio by ELISA.

RESULTS

Paroxetine treatment led to >  80% serotonin transporter occupancy. The treatment increased the body weight of wildtype mice, but not of APPswe/PS1 ΔE9 mice. The treatment had no effect on the Aβ plaque load (p = 0.39), the number and size of plaques, or the Aβ plaque-induced increases in microglial numbers in the dentate gyrus. Three months of serotonin depletion did not significantly impact the Aβ plaque load or Aβ 42/Aβ 40 ratio in APPswe/PS1 ΔE9 mice at 12 months.

CONCLUSION

Our results show that chronic treatment with the SSRI paroxetine does not mitigate Aβ pathology and Aβ plaque-induced microgliosis in the hippocampus of APPswe/PS1 ΔE9 mice.

Systemic inflammatory response in robot-assisted and laparoscopic surgery for colon cancer (SIRIRALS): study protocol of a randomized controlled trial

Background

Robot-assisted surgery is being increasingly adopted in treating colorectal cancer, and the transition from laparoscopic surgery to robot-assisted surgery is a trend. The evidence of the benefits of robot-assisted surgery is sparse. However, findings are associated with improved patient-related outcomes and overall morbidity rates compared to laparoscopic surgery. This induction is unclear, considering both surgical modalities are characterized as minimally invasive. This study aims to evaluate the systemic and peritoneal inflammatory stress response induced by robot-assisted surgery compared with laparoscopic surgery for elective colon cancer resections in a prospective, randomized controlled clinical trial.

Methods

This study is a single-centre randomized controlled superiority trial with 50 colon cancer participants. The primary endpoint is the level of systemic inflammatory response expressed as serum C-reactive protein (CRP) and interleukin 6 (IL-6) levels between postoperative days one and three. Secondary endpoints include (i) levels of systemic inflammation in serum expressed by a panel of inflammatory and pro-inflammatory cytokines measured during the first three postoperative days, (ii) postoperative surgical and medical complications (30 days) according to Clavien-Dindo classification and Comprehensive Complication Index, (iii) intraoperative blood loss, (iv) conversion rate to open surgery, (v) length of surgery, (vi) operative time, (vii) the number of harvested lymph nodes, and (viii) length of hospital stay. The exploratory endpoints are (i) levels of peritoneal inflammatory response in peritoneal fluid expressed by inflammatory and pro-inflammatory cytokines between postoperative day one and three, (ii) patient-reported health-related quality of recovery-15 (QoR-15), (iii) 30 days mortality rate, (iv) heart rate variability and (v) gene transcript (mRNA) analysis.

Discussion

To our knowledge, this is the first clinical randomized controlled trial to clarify the inflammatory stress response induced by robot-assisted or laparoscopic surgery for colon cancer resections.

Trial registration This trial is registered at Clinicaltrials.gov (Identifier: NCT04687384) on December, 29, 2020, Regional committee on health research ethics, Region of Southern Denmark (N75709) and Data Protection Agency, Hospital Sønderjylland, University Hospital of Southern Denmark (N20/46179).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12893-021-01355-4.

The inflammatory response of the supraspinatus muscle in rotator cuff tear conditions

BACKGROUND

Rotator cuff (RC) disorders involve a spectrum of shoulder conditions from early tendinopathy to full-thickness tears leading to impaired shoulder function and pain. The pathology of RC disorder is, nonetheless, still largely unknown. Our hypothesis is that a supraspinatus (SS) tendon tear leads to sustained inflammatory changes of the SS muscle along with fatty infiltration and muscle degeneration, which are threshold markers for poor RC muscle function. The aim of this study was to determine the extent of this muscle inflammation in conjunction with lipid accumulation and fibrosis in RC tear conditions.

METHODS

We used proteomics, histology, electrochemiluminescence immunoassay, and quantitative polymerase chain reaction analyses to evaluate inflammatory and degenerative markers and fatty infiltration in biopsies from 22 patients undergoing surgery with repair of a full-thickness SS tendon tear.

RESULTS

Bioinformatic analysis showed that proteins involved in innate immunity, extracellular matrix organization, and lipid metabolism were among the most upregulated, whereas mitochondrial electronic transport chain along with muscle fiber function was among the most downregulated. Histologic analysis confirmed changes in muscle fiber organization and the presence of inflammation and fatty infiltration. Inflammation appeared to be driven by a high number of infiltrating macrophages, accompanied by elevated matrix metalloprotease levels and changes in transforming growth factor-β and cytokine levels in the SS compared with the deltoid muscle.

CONCLUSIONS

We demonstrated massive SS muscle inflammation after the tendon tear combined with fatty infiltration and degeneration. The regulation of tissue repair is thus extremely complex, and it may have opposite effects at different time points of healing. Inhibition or stimulation of muscle inflammation may be a potential target to enhance the outcome of the repaired torn RC.

Association of acute inflammatory cytokines, fracture malreduction, and functional outcome 12 months after intra-articular ankle fracture-a prospective cohort study of 46 patients with ankle fractures

BACKGROUND

Several malreduction criteria have been proposed for ankle surgery, but the criteria of most importance for functional outcome remain undetermined. Furthermore, the acute inflammatory response in the ankle joint after fracture is hypothesized to result in osteoarthritis development, but no study has investigated the correlation between the levels of these inflammatory cytokines and post-surgical functional outcomes. We aimed to identify malreduction criteria and inflammatory cytokines associated with functional outcome after ankle surgery.

METHODS

During surgery, synovial fluid from the fractured and healthy contralateral ankles of 46 patients was collected for chemiluminescence analysis of 22 inflammatory cytokines and metabolic proteins. The quality of fracture reduction was based on 9 criteria on plain X-rays and 5 criteria on weight-bearing computed tomography (WBCT) scans. After 3 and 12 months, we recorded scores on American Orthopedic Foot and Ankle Society (AOFAS) scale, the Danish version of Foot Function Index (FFI-DK), EQ-5D-5L index score, the Kellgren-Lawrence score, and joint space narrowing.

RESULTS

Tibiofibular (TF) overlap (p = 0.02) and dime sign (p = 0.008) correlated with FFI-DK. Tibiotalar tilt correlated positively with joint space narrowing at 3 months (p = 0.01) and 12 months (p = 0.03). TF widening correlated with FFI-DK (p = 0.04), AOFAS (p = 0.02), and EQ-5D-5L (p = 0.02). No consistent correlations between synovial cytokine levels and functional outcomes were found at 12 months.

CONCLUSIONS

Malreduction of TF overlap, TF widening, and tibiotalar tilt were the most important criteria for functional outcome after ankle surgery. Increased inflammatory cytokine levels after fracture did not affect functional outcome at 12 months.

TRIAL REGISTRATION

This cohort study is registered the 10th of December 2018 at ClinicalTrials.gov ( NCT03769909 ), was approved by the local committee on health ethics (The Regional Committees on Health Research Ethics for Southern Denmark: J.No. S-20170139), and was reported to the National Danish Data Protection Agency (17/28505).

Bone Marrow-Derived IL-1Ra Increases TNF Levels Poststroke

Tumor necrosis factor (TNF) and interleukin-1 receptor antagonist (IL-1Ra) are key players in stroke, a disease in which cell-based therapies have shown great potential. Having shown an infarct-reducing effect of bone marrow (BM) cells, especially cells with high IL-1Ra expression, we here investigated the effect of BM cells on TNF and other stroke-related mediators in mice after transient middle cerebral artery occlusion (tMCAo) and in vitro using adult microglial cultures. We analyzed stroke-related genes and inflammatory mediators using qPCR stroke Tier panels, electrochemiluminescence, or enzyme-linked immunosorbent assays. We found a significant correlation and cellular colocalization between microglial-derived TNF and IL-1Ra, though IL-1Ra production was TNF independent. BM treatment significantly increased TNF, interleukin (IL)-10, and IL-4 levels, while C-X-C motif ligand 1 (CXCL1), IL-12p70, and Toll-like receptor 2 (TLR2) decreased, suggesting that BM treatment favors an anti-inflammatory environment. Hierarchical clustering identified Tnf and IL-1rn within the same gene cluster, and subsequent STRING analysis identified TLR2 as a shared receptor. Although IL-1Ra producing BM cells specifically modulated TNF levels, this was TLR2 independent. These results demonstrate BM cells as modulators of poststroke inflammation with beneficial effects on poststroke outcomes and place TNF and IL-1Ra as key players of the defense response after tMCAo.

The Role of Non-Selective TNF Inhibitors in Demyelinating Events

The use of non-selective tumor necrosis factor (TNF) inhibitors is well known in the treatment of inflammatory diseases such as rheumatoid arthritis, Crohn’s disease, and psoriasis. Its use in neurological disorders is limited however, due to rare adverse events of demyelination, even in patients without preceding demyelinating disease. We review here the molecular and cellular aspects of this neuroinflammatory process in light of a case of severe monophasic demyelination caused by treatment with infliximab. Focusing on the role of TNF, we review the links between CNS inflammation, demyelination, and neurodegenerative changes leading to permanent neurological deficits in a young woman, and we discuss the growing evidence for selective soluble TNF inhibitors as a new treatment approach in inflammatory and neurological diseases.

Conditional Ablation of Myeloid TNF Improves Functional Outcome and Decreases Lesion Size after Spinal Cord Injury in Mice

Spinal cord injury (SCI) is a devastating condition consisting of an instant primary mechanical injury followed by a secondary injury that progresses for weeks to months. The cytokine tumor necrosis factor (TNF) plays an important role in the pathophysiology of SCI. We investigated the effect of myeloid TNF ablation (peripheral myeloid cells (macrophages and neutrophils) and microglia) versus central myeloid TNF ablation (microglia) in a SCI contusion model. We show that TNF ablation in macrophages and neutrophils leads to reduced lesion volume and improved functional outcome after SCI. In contrast, TNF ablation in microglia only or TNF deficiency in all cells had no effect. TNF levels tended to be decreased 3 h post-SCI in mice with peripheral myeloid TNF ablation and was significantly decreased 3 days after SCI. Leukocyte and microglia populations and all other cytokines (IL-1β, IL-2, IL-4, IL-5, IL-6, IL-10, IL-12, and IFNγ) and chemokines (CCL2, CCL5, and CXCL1) investigated, in addition to TNFR1 and TNFR2, were comparable between genotypes. Analysis of post-SCI signaling cascades demonstrated that the MAPK kinase SAPK/JNK decreased and neuronal Bcl-XL levels increased post-SCI in mice with ablation of TNF in peripheral myeloid cells. These findings demonstrate that peripheral myeloid cell-derived TNF is pathogenic in SCI.

Supraspinatus and deltoid muscle fiber composition in rotator cuff tear conditions

Background

Rotator cuff (RC) tears are associated with RC muscle atrophy and changes in composition that are crucial to the prognosis of RC repair. The aim of this study was to characterize muscle fiber composition in the supraspinatus (SS) muscle under tear conditions.

Methods

Muscle biopsies were obtained from 21 patients undergoing surgery for an RC tendon tear. Biopsies were obtained from the musculotendinous junction of the SS muscle, and control biopsies were harvested from the deltoid muscle (DT). Biopsies were immunohistochemically processed for detection of type 1 (slow type) and type 2 (fast type) fibers and analyzed using unbiased, stereological principles. We counted the total numbers of type 1 and 2 muscle fibers/mm², and fiber diameter was used to estimate muscle fiber atrophy and hypertrophy.

Results

We found significantly more type 2 cells/mm² in the SS compared with the DT (P < .01). In addition, we found a significantly higher fraction of type 1 fibers than type 2 fibers in the DT (P < .01), whereas both fiber types were equally present in the SS. The diameters of SS cells were generally smaller than those of DT cells. Atrophy of especially SS type 2 fibers was also demonstrated. Fiber atrophy was more pronounced in men than women.

Conclusion

The changes in the composition of SS muscle cell types suggest a shift from type 1 to type 2 muscle fibers and atrophy of both type 1 and 2 fibers. This composition indicates loss of endurance and rapid fatigue of the SS muscle under RC tear conditions.

Diagnosis and long-term outcome in dogs with acute onset intracranial signs

OBJECTIVES

To investigate dogs with acute onset of intracranial signs suspected of stroke by primary veterinary clinicians, and establish possible differential diagnoses and long-term outcome. In addition, serum C-reactive protein and plasma cytokines were investigated as potential biomarkers of disease.

MATERIALS AND METHODS

All cases were evaluated by neurologic examination, routine haematology and biochemistry and measurement of serum C-reactive protein, plasma cytokine concentrations (interleukin-2, -6, -8, -10, tumour necrosis factor) and low-field MRI.

RESULTS

Primary veterinarians contacted the investigators with 85 suspected stroke cases. Only 20 met the inclusion criteria. Of these, two were diagnosed with ischaemic stroke. Other causes were idiopathic vestibular syndrome (n=6), brain tumour (n=5) and inflammatory brain disease (n=2); in five cases a precise diagnosis could not be determined. Median survival times were: brain tumour, 3 days, idiopathic vestibular syndrome, 315 days, ischaemic stroke, 365 days and inflammatory central nervous system (CNS) disease, 468 days. The median plasma concentrations of interleukin-2, -6, -8, -10 or tumour necrosis factor were not significantly increased in any of the diagnosis groups compared to healthy controls. Serum C-reactive protein was higher in dogs with brain tumours and inflammatory brain disease but not above the upper bound of the reference interval.

CLINICAL SIGNIFICANCE

Dogs that present with acute onset intracranial disease may have ischaemic stroke but are more likely to have other causes. Many dogs with such acute onset of neurological dysfunction (brain tumours excluded) may recover within a couple of weeks despite their initial severe clinical appearance.

TNF deficiency causes alterations in the spatial organization of neurogenic zones and alters the number of microglia and neurons in the cerebral cortex

BACKGROUND

Although tumor necrosis factor (TNF) inhibitors are used to treat chronic inflammatory diseases, there is little information about how long-term inhibition of TNF affects the homeostatic functions that TNF maintains in the intact CNS.

MATERIALS AND METHODS

To assess whether developmental TNF deficiency causes alterations in the naïve CNS, we estimated the number of proliferating cells, microglia, and neurons in the developing neocortex of E13.5, P7 and adult TNF knock out (TNF^-/-) mice and wildtype (WT) littermates. We also measured changes in gene and protein expression and monoamine levels in adult WT and TNF^-/- mice. To evaluate long-term effects of TNF inhibitors, we treated healthy adult C57BL/6 mice with either saline, the selective soluble TNF inhibitor XPro1595, or the nonselective TNF inhibitor etanercept. We estimated changes in cell number and protein expression after two months of treatment. We assessed the effects of TNF deficiency on cognition by testing adult WT and TNF^-/- mice and mice treated with saline, XPro1595, or etanercept with specific behavioral tasks.

RESULTS

TNF deficiency decreased the number of proliferating cells and microglia and increased the number of neurons. At the same time, TNF deficiency decreased the expression of WNT signaling-related proteins, specifically Collagen Triple Helix Repeat Containing 1 (CTHRC1) and Frizzled receptor 6 (FZD6). In contrast to XPro1595, long-term inhibition of TNF with etanercept in adult C57BL/6 mice decreased the number of BrdU⁺ cells in the granule cell layer of the dentate gyrus. Etanercept, but not XPro1595, also impaired spatial learning and memory in the Barnes maze memory test.

CONCLUSION

TNF deficiency impacts the organization of neurogenic zones and alters the cell composition in brain. Long-term inhibition of TNF with the nonselective TNF inhibitor etanercept, but not the soluble TNF inhibitor XPro1595, decreases neurogenesis in the adult mouse hippocampus and impairs learning and memory after two months of treatment.

Topical Administration of a Soluble TNF Inhibitor Reduces Infarct Volume After Focal Cerebral Ischemia in Mice

Background

Tumor necrosis factor, which exists both as a soluble (solTNF) and a transmembrane (tmTNF) protein, plays an important role in post-stroke inflammation. The objective of the present study was to test the effect of topical versus intracerebroventricular administration of XPro1595 (a solTNF inhibitor) and etanercept (a solTNF and tmTNF inhibitor) compared to saline on output measures such as infarct volume and post-stroke inflammation in mice.

Methods

Adult male C57BL/6 mice were treated topically (2.5 mg/ml/1μl/h for 3 consecutive days) or intracerebroventricularly (1.25 mg/kg/0.5 ml, once) with saline, XPro1595, or etanercept immediately after permanent middle cerebral artery occlusion (pMCAO). Mice were allowed to survive 1 or 3 days. Infarct volume, microglial and leukocyte profiles, and inflammatory markers were evaluated.

Results

We found that topical, and not intracerebroventricular, administration of XPro1595 reduced infarct volume at both 1 and 3 days after pMCAO. Etanercept showed no effect. We observed no changes in microglial or leukocyte populations. XPro1595 increased gene expression of P2ry12 at 1 day and Trem2 at 1 and 3 days, while decreasing Cx3cr1 expression at 1 and 3 days after pMCAO, suggesting a change in microglial activation toward a phagocytic phenotype.

Conclusion

Our data demonstrate that topical administration of XPro1595 for 3 consecutive days decreases infarct volumes after ischemic stroke, while modifying microglial activation and the inflammatory response post-stroke. This suggests that inhibitors of solTNF hold great promise for future neuroprotective treatment in ischemic stroke.

Effect of Home-Based High-Intensity Interval Training in Patients With Lacunar Stroke: A Randomized Controlled Trial

Background: High-intensity interval training (HIIT) is superior to moderate-intensity continuous training in improving cardiorespiratory fitness in patients with cardiovascular disease, but is it safe, feasible and effective in patients with stroke? We investigated feasibility and effect of early, home-based HIIT in patients with lacunar stroke combined with usual care vs. usual care, only. Methods: Patients with minor stroke (severity: 55/58 point on the Scandinavian Stroke Scale) were randomized to HIIT or usual care in a randomized, controlled trial. We measured the following outcomes at baseline and post-intervention: cardiorespiratory fitness monitored as power output from the Graded Cycling Test with Talk Test (GCT-TT; primary outcome), physical activity, fatigue, depression, well-being, stress, cognition, endothelial function, blood pressure, body mass index, and biomarkers. Results: We included 71 patients (mean age 63.7 ± 9.2), 49 men, 31 in intervention group. Home-based HIIT was feasible with no reported adverse events in relation to the intervention. No significant change between the groups in GCT-TT power output was detected (p = 0.90). The change in time spent on vigorous-intensity activity was 2 h/week and 0.6 h/week, intervention and usual care, respectively (p = 0.045). There were no significant differences between groups in the remaining secondary outcomes. Conclusion: HIIT was feasible and safe in patients with lacunar stroke. Patients can engage early in home-based HIIT when involved in choosing exercise modality and guided by weekly motivational phone calls. Within 3 months, HIIT did, however, not yield effect on cardiorespiratory fitness. We await further evaluation of long-term effects of this intervention on continued regular physical exercise and cardiovascular event. Clinical Trial Registration: https://clinicaltrials.gov, identifier NCT02731235.

Musculoskeletal application and validation of speckle-tracking ultrasonography

Background

Diseased, injured, or dysfunctional skeletal muscles may demonstrate abnormal function and contractility. Currently, only few in vivo imaging techniques are able to characterize the contractile properties of muscle tissue. This study aimed to test the hypothesis that muscle strain can be tracked in two upper extremity skeletal muscles by speckle-tracking ultrasonography (STU) and correlates with isometric muscle contractions.

Methods

A convenience sample of 10 healthy, adult volunteers with normal shoulder function were tested. The 5 women and 5 men had a mean age of 45 years (range: 39–59 years) and BMI < 30. STU was applied to the supraspinatus (SS) and biceps brachii (BB) muscles using a M11 L-MHz linear transducer (frequency 8–15 MHz) hooked to a Vivid E 9TM ultrasound machine. Strain validation was performed by correlating peak strain against standardized sub-maximal, isometric load conditions of the two muscles (20–80% of maximal voluntary contraction) using a custom-built muscle dynamometer based on strain-gauge technique. Data were analyzed offline using the EchoPac speckle-tracking software and were blinded to the examiner.

Results

Intramuscular strain measured by STU in the SS and BB muscles showed moderate to strong correlations with external muscle load (SS: r = − 0.76, p < 0.0001 and BB: r = − 0.60, p < 0.0001). We found strain to vary from approximately 10–20% during increasing submaximal, isometric conditions.

Conclusions

We demonstrate that STU can be applied on healthy skeletal musculature (SS and BB muscles). The observed correlations between strain and isometric contractions suggest a valid technique. However, the concept of measuring muscle strain non-invasively needs further investigation for validity, accuracy, responsiveness, and reliability before its therapeutic and research potential can be realized.

Post-stroke inflammation-target or tool for therapy?

Inflammation is currently considered a prime target for the development of new stroke therapies. In the acute phase of ischemic stroke, microglia are activated and then circulating immune cells invade the peri-infarct and infarct core. Resident and infiltrating cells together orchestrate the post-stroke inflammatory response, communicating with each other and the ischemic neurons, through soluble and membrane-bound signaling molecules, including cytokines. Inflammation can be both detrimental and beneficial at particular stages after a stroke. While it can contribute to expansion of the infarct, it is also responsible for infarct resolution, and influences remodeling and repair. Several pre-clinical and clinical proof-of-concept studies have suggested the effectiveness of pharmacological interventions that target inflammation post-stroke. Experimental evidence shows that targeting certain inflammatory cytokines, such as tumor necrosis factor, interleukin (IL)-1, IL-6, and IL-10, holds promise. However, as these cytokines possess non-redundant protective and immunoregulatory functions, their neutralization or augmentation carries a risk of unwanted side effects, and clinical translation is, therefore, challenging. This review summarizes the cell biology of the post-stroke inflammatory response and discusses pharmacological interventions targeting inflammation in the acute phase after a stroke that may be used alone or in combination with recanalization therapies. Development of next-generation immune therapies should ideally aim at selectively neutralizing pathogenic immune signaling, enhancing tissue preservation, promoting neurological recovery and leaving normal function intact.

Abstract WP191: Short-term Follow-up After Early Home-based High-intensity Interval Training in Stroke

Background: High-intensity interval training (HIIT) is superior to moderate-intensity continuous training (MICE) in improving aerobic fitness in patients with cardiovascular disease. Few studies have investigated the effect of HIIT in patients with stroke and none specifically in patients with small vessel disease stroke (SVDS).

Purpose: We aimed to investigate the short-term effect of 12-weeks home-based HIIT post stroke in addition to usual care, versus usual care only.

Methods: We included 71 patients with SVDS in a randomised controlled trial, intervention vs. control 1:1. At baseline and after 3 months we assessed: aerobic fitness (power output from the Graded Cycling Test with Talk Test (GCT-TT)), physical activity, fatigue, depression, well-being, stress, cognition, endothelial function, blood pressure, body mass index, and blood biomarkers.

Results: We found that the patients in the intervention group spent more time on vigorous-intensity activity than the usual care group. Home-based HIIT was feasible, with no adverse events reported. No significant difference was detected in GCT-TT power output between groups. Further, we found no significant differences between the groups in general well-being (depression, stress, fatigue, cognition, and quality of life). Insulin levels decreased slightly in the active group (p=0.048).

Conclusion: Importantly, this study shows that patients with SVDS can engage in home-based HIIT when encouraged weekly by phone, and provided either a stationary bicycle or choosing a high intensity activity of their own interest. However, increased activity was not reflected in short-term effect on aerobic fitness. This may be due to a lower than requested intensity or duration of activity. We need more investigations on long-term effects, and how to further increase physical activity and aerobic fitness.

Inflammation leads to distinct populations of extracellular vesicles from microglia

Background

Activated microglia play an essential role in inflammatory responses elicited in the central nervous system (CNS). Microglia-derived extracellular vesicles (EVs) are suggested to be involved in propagation of inflammatory signals and in the modulation of cell-to-cell communication. However, there is a lack of knowledge on the regulation of EVs and how this in turn facilitates the communication between cells in the brain. Here, we characterized microglial EVs under inflammatory conditions and investigated the effects of inflammation on the EV size, quantity, and protein content.

Methods

We have utilized western blot, nanoparticle tracking analysis (NTA), and mass spectrometry to characterize EVs and examine the alterations of secreted EVs from a microglial cell line (BV2) following lipopolysaccharide (LPS) and tumor necrosis factor (TNF) inhibitor (etanercept) treatments, or either alone. The inflammatory responses were measured with multiplex cytokine ELISA and western blot. We also subjected TNF knockout mice to experimental stroke (permanent middle cerebral artery occlusion) and validated the effect of TNF inhibition on EV release.

Results

Our analysis of EVs originating from activated BV2 microglia revealed a significant increase in the intravesicular levels of TNF and interleukin (IL)-6. We also observed that the number of EVs released was reduced both in vitro and in vivo when inflammation was inhibited via the TNF pathway. Finally, via mass spectrometry, we identified 49 unique proteins in EVs released from LPS-activated microglia compared to control EVs (58 proteins in EVs released from LPS-activated microglia and 37 from control EVs). According to Gene Ontology (GO) analysis, we found a large increase of proteins related to translation and transcription in EVs from LPS. Importantly, we showed a distinct profile of proteins found in EVs released from LPS treated cells compared to control.

Conclusions

We demonstrate altered EV production in BV2 microglial cells and altered cytokine levels and protein composition carried by EVs in response to LPS challenge. Our findings provide new insights into the potential roles of EVs that could be related to the pathogenesis in neuroinflammatory diseases.

Electronic supplementary material

The online version of this article (10.1186/s12974-018-1204-7) contains supplementary material, which is available to authorized users.

Neuronal Rho GTPase Rac1 elimination confers neuroprotection in a mouse model of permanent ischemic stroke

The Rho GTPase Rac1 is a multifunctional protein involved in distinct pathways ranging from development to pathology. The aim of the present study was to unravel the contribution of neuronal Rac1 in regulating the response to brain injury induced by permanent focal cerebral ischemia (pMCAO). Our results show that pMCAO significantly increased total Rac1 levels in wild type mice, mainly through rising nuclear Rac1, while a reduction in Rac1 activation was observed. Such changes preceded cell death induced by excitotoxic stress. Pharmacological inhibition of Rac1 in primary neuronal cortical cells prevented the increase in oxidative stress induced after overactivation of glutamate receptors. However, this was not sufficient to prevent the associated neuronal cell death. In contrast, RNAi-mediated knock down of Rac1 in primary cortical neurons prevented cell death elicited by glutamate excitotoxicity and decreased the activity of NADPH oxidase. To test whether in vivo down regulation of neuronal Rac1 was neuroprotective after pMCAO, we used tamoxifen-inducible neuron-specific conditional Rac1-knockout mice. We observed a significant 50% decrease in brain infarct volume of knockout mice and a concomitant increase in HIF-1α expression compared to littermate control mice, demonstrating that ablation of Rac1 in neurons is neuroprotective. Transmission electron microscopy performed in the ischemic brain showed that lysosomes in the infarct of Rac1- knockout mice were preserved at similar levels to those of non-infarcted tissue, while littermate mice displayed a decrease in the number of lysosomes, further corroborating the notion that Rac1 ablation in neurons is neuroprotective. Our results demonstrate that Rac1 plays important roles in the ischemic pathological cascade and that modulation of its levels is of therapeutic interest.

Beneficial potential of intravenously administered IL-6 in improving outcome after murine experimental stroke

Interleukin-6 (IL-6) is a pleiotropic cytokine with neuroprotective properties. Still, the therapeutic potential of IL-6 after experimental stroke has not yet been investigated in a clinically relevant way. Here, we investigated the therapeutic use of intravenously administered IL-6 and the soluble IL-6 receptor (sIL-6R) alone or in combination, early after permanent middle cerebral artery occlusion (pMCAo) in mice. IL-6 did not affect the infarct volume in C57BL/6 mice, at neither 24 nor 72h after pMCAo but reduced the infarct volume in IL-6 knockout mice at 24h after pMCAo. Assessment of post-stroke behavior showed an improved grip strength after a single IL-6 injection and also improved rotarod endurance after two injections, in C57BL/6 mice at 24h. An improved grip strength and a better preservation of sensory functions was also observed in IL-6 treated IL-6 knockout mice 24h after pMCAo. Co-administration of IL-6 and sIL-6R increased the infarct volume, the number of infiltrating polymorphonuclear leukocytes and impaired the rotarod endurance of C57BL/6 mice 24h after pMCAo. IL-6 administration to naïve C57BL/6 mice lead after 45min to increased plasma-levels of CXCL1 and IL-10, whereas IL-6 administration to C57BL/6 mice lead to a reduction in the ischemia-induced increase in IL-6 and CXCL1 at both mRNA and protein level in brain, and of IL-6 and CXCL1 in serum. We also investigated the expression of IL-6 and IL-6R after pMCAo and found that cortical neurons upregulated IL-6 mRNA and protein, and upregulated IL-6R after pMCAo. In conclusion, the results show a complex but potentially beneficial effect of intravenously administered IL-6 in experimental stroke.

The loss-of-function disease-mutation G301R in the Na+/K+-ATPase α2 isoform decreases lesion volume and improves functional outcome after acute spinal cord injury in mice

Background

The Na⁺/K⁺-ATPases are transmembrane ion pumps important for maintenance of ion gradients across the plasma membrane that serve to support multiple cellular functions, such as membrane potentials, regulation of cellular volume and pH, and co-transport of signaling transmitters in all animal cells. The α₂Na⁺/K⁺-ATPase subunit isoform is predominantly expressed in astrocytes, which us the sharp Na⁺-gradient maintained by the sodium pump necessary for astroglial metabolism. Prolonged ischemia induces an elevation of [Na⁺]_i, decreased ATP levels and intracellular pH owing to anaerobic metabolism and lactate accumulation. During ischemia, Na⁺/K⁺-ATPase-related functions will naturally increase the energy demand of the Na⁺/K⁺-ATPase ion pump. However, the role of the α₂Na⁺/K⁺-ATPase in contusion injury to the spinal cord remains unknown. We used mice heterozygous mice for the loss-of-function disease-mutation G301R in the Atp1a2 gene (α₂^+/G301R) to study the effect of reduced α₂Na⁺/K⁺-ATPase expression in a moderate contusion spinal cord injury (SCI) model.

Results

We found that α₂^+/G301R mice display significantly improved functional recovery and decreased lesion volume compared to littermate controls (α₂^+/+) 7 days after SCI. The protein level of the α₁ isoform was significantly increased, in contrast to the α₃ isoform that significantly decreased 3 days after SCI in both α₂^+/G301R and α₂^+/+ mice. The level of the α₂ isoform was significantly decreased in α₂^+/G301R mice both under naïve conditions and 3 days after SCI compared to α₂^+/+ mice. We found no differences in astroglial aquaporin 4 levels and no changes in the expression of chemokines (CCL2, CCL5 and CXCL1) and cytokines (TNF, IL-6, IL-1β, IL-10 and IL-5) between genotypes, just as no apparent differences were observed in location and activation of CD45 and F4/80 positive microglia and infiltrating leukocytes.

Conclusion

Our proof of concept study demonstrates that reduced expression of the α₂ isoform in the spinal cord is protective following SCI. Importantly, the BMS and lesion volume were assessed at 7 days after SCI, and longer time points after SCI were not evaluated. However, the α₂ isoform is a potential possible target of therapeutic strategies for the treatment of SCI.

Neuronal Ablation of IKK2 Decreases Lesion Size and Improves Functional Outcome after Spinal Cord Injury in Mice

Nuclear factor-kappa B (NF-κB) is a key modulator of inflammation and secondary injury responses in neurodegenerative disease, including spinal cord injury (SCI). Inhibition of astroglial NF-κB reduces inflammation, enhances oligodendrogenesis and improves functional recovery after SCI, however the contribution of neuronal NF-κB to secondary inflammatory responses following SCI has yet to be investigated. We demonstrate that conditional ablation of IKK2 in Synapsin 1-expressing neurons in mice (Syn1creIKK2^fl/fl) reduces activation of the classical NF-κB signaling pathway, resulting in impaired motor function and altered memory retention under naïve conditions. Following induction of a moderate SCI phosphorylated NF-κB levels decreased in the spinal cord of Syn1creIKK2^fl/fl mice compared to controls, resulting in improvement in functional recovery. Histologically, Syn1creIKK2^fl/fl mice exhibited reduced lesion volume but comparable microglial/leukocyte responses after SCI. In parallel, interleukin (IL)-1β expression was significantly decreased within the lesioned spinal cord, whereas IL-5, IL-6, IL-10, tumor necrosis factor (TNF) and chemokine (C-X-C motif) ligand 1 were unchanged compared to control mice. We conclude that conditional ablation of IKK2 in neurons, resulting in reduced neuronal NF-B signaling, and lead to protective effects after SCI and propose the neuronal classical NF-κB pathway as a potential target for the development of new therapeutic, neuroprotective strategies for SCI.

Fumarate decreases edema volume and improves functional outcome after experimental stroke

BACKGROUND

Oxidative stress and inflammation exacerbate tissue damage in the brain after ischemic stroke. Dimethyl-fumarate (DMF) and its metabolite monomethyl-fumarate (MMF) are known to stimulate anti-oxidant pathways and modulate inflammatory responses. Considering these dual effects of fumarates, we examined the effect of MMF treatment after ischemic stroke in mice.

METHODS

Permanent middle cerebral artery occlusion (pMCAO) was performed using adult, male C57BL/6 mice. Thirty minutes after pMCAO, 20mg/kg MMF was administered intravenously. Outcomes were evaluated 6, 24 and 48h after pMCAO. First, we examined whether a bolus of MMF was capable of changing expression of kelch-like erythroid cell-derived protein with CNC homology-associated protein 1 (Keap1) and nuclear factor erythroid 2-related factor (Nrf)2 in the infarcted brain. Next, we studied the effect of MMF on functional recovery. To explore mechanisms potentially influencing functional changes, we examined infarct volumes, edema formation, the expression of heat shock protein (Hsp)72, hydroxycarboxylic acid receptor 2 (Hcar2), and inducible nitric oxide synthase (iNOS) in the infarcted brain using real-time PCR and Western blotting. Concentrations of a panel of pro- and anti-inflammatory cytokines (IFNγ, IL-1β, IL-2, IL-4, IL-5, IL-6, IL-10, IL-12p70, TNF) were examined in both the infarcted brain tissue and plasma samples 6, 24 and 48h after pMCAO using multiplex electrochemoluminiscence analysis.

RESULTS

Administration of MMF increased the protein level of Nrf2 6h after pMCAO, and improved functional outcome at 24 and 48h after pMCAO. MMF treatment did not influence infarct size, however reduced edema volume at both 24 and 48h after pMCAO. MMF treatment resulted in increased Hsp72 expression in the brain 6h after pMCAO. Hcar2 mRNA levels increased significantly 24h after pMCAO, but were not different between saline- and MMF-treated mice. MMF treatment also increased the level of the anti-inflammatory cytokine IL-10 in the brain and plasma 6h after pMCAO, and additionally reduced the level of the pro-inflammatory cytokine IL-12p70 in the brain at 24 and 48h after pMCAO.

CONCLUSIONS

A single intravenous bolus of MMF improved sensory-motor function after ischemic stroke, reduced edema formation, and increased the levels of the neuroprotective protein Hsp72 in the brain. The early increase in IL-10 and reduction in IL-12p70 in the brain combined with changes in systemic cytokine levels may also contribute to the functional recovery after pMCAO.

Spontaneous ischaemic stroke lesions in a dog brain: neuropathological characterisation and comparison to human ischaemic stroke

BACKGROUND

Dogs develop spontaneous ischaemic stroke with a clinical picture closely resembling human ischaemic stroke patients. Animal stroke models have been developed, but it has proved difficult to translate results obtained from such models into successful therapeutic strategies in human stroke patients. In order to face this apparent translational gap within stroke research, dogs with ischaemic stroke constitute an opportunity to study the neuropathology of ischaemic stroke in an animal species.

CASE PRESENTATION

A 7 years and 8 months old female neutered Rottweiler dog suffered a middle cerebral artery infarct and was euthanized 3 days after onset of neurological signs. The brain was subjected to histopathology and immunohistochemistry. Neuropathological changes were characterised by a pan-necrotic infarct surrounded by peri-infarct injured neurons and reactive microglia/macrophages and astrocytes.

CONCLUSIONS

The neuropathological changes reported in the present study were similar to findings in human patients with ischaemic stroke. The dog with spontaneous ischaemic stroke is of interest as a complementary spontaneous animal model for further neuropathological studies.

Conditional ablation of myeloid TNF increases lesion volume after experimental stroke in mice, possibly via altered ERK1/2 signaling

Microglia are activated following cerebral ischemia and increase their production of the neuro- and immunomodulatory cytokine tumor necrosis factor (TNF). To address the function of TNF from this cellular source in focal cerebral ischemia we used TNF conditional knock out mice (LysMcreTNF^fl/fl) in which the TNF gene was deleted in cells of the myeloid lineage, including microglia. The deletion reduced secreted TNF levels in lipopolysaccharide-stimulated cultured primary microglia by ~93%. Furthermore, phosphorylated-ERK/ERK ratios were significantly decreased in naïve LysMcreTNF^fl/fl mice demonstrating altered ERK signal transduction. Micro-PET using ¹⁸[F]-fluorodeoxyglucose immediately after focal cerebral ischemia showed increased glucose uptake in LysMcreTNF^fl/fl mice, representing significant metabolic changes, that translated into increased infarct volumes at 24 hours and 5 days compared to littermates (TNFfl/fl). In naïve LysMcreTNF^fl/fl mice cytokine levels were low and comparable to littermates. At 6 hours, TNF producing microglia were reduced by 56% in the ischemic cortex in LysMcreTNF^fl/fl mice compared to littermate mice, whereas no TNF⁺ leukocytes were detected. At 24 hours, pro-inflammatory cytokine (TNF, IL-1β, IL-6, IL-5 and CXCL1) levels were significantly lower in LysMcreTNF^fl/fl mice, despite comparable infiltrating leukocyte populations. Our results identify microglial TNF as beneficial and neuroprotective in the acute phase and as a modulator of neuroinflammation at later time points after experimental ischemia, which may contribute to regenerative recovery.

Cell therapy centered on IL-1Ra is neuroprotective in experimental stroke

Cell-based therapies are emerging as new promising treatments in stroke. However, their functional mechanism and therapeutic potential during early infarct maturation has so far received little attention. Here, we asked if cell-based delivery of the interleukin-1 receptor antagonist (IL-1Ra), a known neuroprotectant in stroke, can promote neuroprotection, by modulating the detrimental inflammatory response in the tissue at risk. We show by the use of IL-1Ra-overexpressing and IL-1Ra-deficient mice that IL-1Ra is neuroprotective in stroke. Characterization of the cellular and spatiotemporal production of IL-1Ra and IL-1α/β identifies microglia, not infiltrating leukocytes, as the major sources of IL-1Ra after experimental stroke, and shows IL-1Ra and IL-1β to be produced by segregated subsets of microglia with a small proportion of these cells co-expressing IL-1α. Reconstitution of whole body irradiated mice with IL-1Ra-producing bone marrow cells is associated with neuroprotection and recruitment of IL-1Ra-producing leukocytes after stroke. Neuroprotection is also achieved by therapeutic injection of IL-1Ra-producing bone marrow cells 30 min after stroke onset, additionally improving the functional outcome in two different stroke models. The IL-1Ra-producing bone marrow cells increase the number of IL-1Ra-producing microglia, reduce the availability of IL-1β, and modulate mitogen-activated protein kinase (MAPK) signaling in the ischemic cortex. The importance of these results is underlined by demonstration of IL-1Ra-producing cells in the human cortex early after ischemic stroke. Taken together, our results attribute distinct neuroprotective or neurotoxic functions to segregated subsets of microglia and suggest that treatment strategies increasing the production of IL-1Ra by infiltrating leukocytes or microglia may also be neuroprotective if applied early after stroke onset in patients.

BID Mediates Oxygen-Glucose Deprivation-Induced Neuronal Injury in Organotypic Hippocampal Slice Cultures and Modulates Tissue Inflammation in a Transient Focal Cerebral Ischemia Model without Changing Lesion Volume

The BH3 interacting-domain death agonist (BID) is a pro-apoptotic protein involved in death receptor-induced and mitochondria-mediated apoptosis. Recently, it has also been suggested that BID is involved in the regulation of inflammatory responses in the central nervous system. We found that BID deficiency protected organotypic hippocampal slice cultures in vitro from neuronal injury induced by oxygen-glucose deprivation. In vivo, BID-knockout (KO) mice and wild type (WT) mice were subjected to 60 min of transient middle cerebral artery occlusion (tMCAO) to induce focal cerebral ischemia, and allowed to recover for 24 h. Infarct volumes and functional outcome were assessed and the inflammatory response was evaluated using immunofluorescence, Western blotting, quantitative PCR (qPCR) and Mesoscale multiplex analysis. We observed no difference in the infarct volume or neurological outcome between BID-KO and WT mice. The inflammatory response was reduced by BID deficiency as indicated by a change in microglial/leukocyte response. In conclusion, our data suggest that BID deficiency is neuroprotective in an in vitro model and modulates the inflammatory response to focal cerebral ischemia in vivo. However, this is not translated into a robust neuroprotection in vivo.

Systemically administered anti-TNF therapy ameliorates functional outcomes after focal cerebral ischemia

Background

The innate immune system contributes to the outcome after stroke, where neuroinflammation and post-stroke systemic immune depression are central features. Tumor necrosis factor (TNF), which exists in both a transmembrane (tm) and soluble (sol) form, is known to sustain complex inflammatory responses associated with stroke. We tested the effect of systemically blocking only solTNF versus blocking both tmTNF and solTNF on infarct volume, functional outcome and inflammation in focal cerebral ischemia.

Methods

We used XPro1595 (a dominant-negative inhibitor of solTNF) and etanercept (which blocks both solTNF and tmTNF) to test the effect of systemic administration on infarct volume, functional recovery and inflammation after focal cerebral ischemia in mice. Functional recovery was evaluated after one, three and five days, and infarct volumes at six hours, 24 hours and five days after ischemia. Brain inflammation, liver acute phase response (APR), spleen and blood leukocyte profiles, along with plasma microvesicle analysis, were evaluated.

Results

We found that both XPro1595 and etanercept significantly improved functional outcomes, altered microglial responses, and modified APR, spleen T cell and microvesicle numbers, but without affecting infarct volumes.

Conclusions

Our data suggest that XPro1595 and etanercept improve functional outcome after focal cerebral ischemia by altering the peripheral immune response, changing blood and spleen cell populations and decreasing granulocyte infiltration into the brain. Blocking solTNF, using XPro1595, was just as efficient as blocking both solTNF and tmTNF using etanercept. Our findings may have implications for future treatments with anti-TNF drugs in TNF-dependent diseases.

Electronic supplementary material

The online version of this article (doi:10.1186/s12974-014-0203-6) contains supplementary material, which is available to authorized users.