Serum level of macrophage migration inhibitory factor predicts severity and prognosis in patients with ischemic stroke

Inflammatory markers in acute ischemic stroke

Acute ischemic stroke (AIS) is associated with a high incidence and significant rates of disability, making it a critical focus of clinical research. The current review investigates the role of serum inflammatory markers in the pathogenesis and prognosis of AIS. By quantitatively analyzing specific inflammatory markers, this study aims to enhance the understanding of the pathophysiological mechanisms underlying AIS, support early diagnosis, improve disease assessment, and establish a scientific foundation for targeted treatment strategies to optimize clinical outcomes. From a pathophysiological perspective, multiple inflammatory markers are involved in the inflammatory response that occurs within brain tissue following cerebral ischemia. The serum levels of various inflammatory markers were measured in individuals with AIS, revealing strong correlations between these markers and disease severity. The findings indicate that these markers can serve as reliable indicators of disease progression. Further analysis demonstrated their prognostic value in predicting functional recovery and the risk of recurrence. Notably, during a 3-month follow-up, each 0.32 ng/mL increase in matrix metalloproteinases-9 levels was associated with a 16 % increase in the risk of disability and mortality after AIS. The findings of this review contribute to a more comprehensive understanding of the pathological and physiological mechanisms of AIS and offer a foundation for advancing early diagnostic methods, disease assessment tools, and personalized treatment strategies. Monitoring inflammatory marker levels may enable clinicians to more accurately evaluate disease severity and develop tailored therapeutic interventions, potentially reducing disability and recurrence rates while improving quality of life for individuals with AIS. The findings highlight the potential of precision medicine approaches based on inflammatory markers to shape future AIS treatment paradigms.

Endothelial progenitor cell-derived conditioned medium mitigates chronic cerebral ischemic injury through macrophage migration inhibitory factor-activated AKT pathway

BACKGROUND

Chronic cerebral ischemia (CCI) is a significant health issue characterized by hypoperfusion due to damage or occlusion of the cerebral or carotid arteries. CCI may lead to progressive cognitive impairment that is considered as a prelude to neurodegenerative diseases, including dementia and Alzheimer's disease (AD). Endothelial progenitor cells (EPCs) have been implicated in vascular repair in ischemic cerebrovascular diseases, primarily by differentiating into endothelial cells (ECs) or through paracrine effects. However, the clinical transplantation of stem cell therapies remains limited. In this study, we investigated the effects of EPC-derived conditioned medium (EPC-CM) on the impaired vasculature and neurological function in a rodent model of CCI and the mechanism involved.

METHODS

EPC-CM was analyzed by cytokine array to identify key factors involved in angiogenesis and cellular senescence. The effects and mechanism of the candidate factors in the EPC-CM were validated in vitro using oxygen-glucose deprivation (OGD)-injured ECs and EPCs. The therapeutic effects of EPC-CM and the identified key factor were further examined in a rat model of CCI, which was induced by bilateral internal carotid artery ligation (BICAL). EPC-CM was administered via intracisternal injection one week post BICAL. The cerebral microvasculature and neurobehavior of the rats were examined three weeks after BICAL.

RESULTS

Macrophage migration inhibitory factor (MIF) was identified as a key factor in the EPC-CM. Recombinant MIF protein promoted angiogenesis and prevented senescence in the injured EPCs and ECs. The effect was similar to that of the EPC-CM. These therapeutic effects were diminished when the EPC-CM was co-treated with MIF-specific antibody (Ab). Additionally, the vascular, motor, and cognitive improvements observed in the BICAL rats treated with EPC-CM were abolished by co-treated with MIF Ab. Furthermore, we found MIF promoted angiogenesis and anti-senescence via activating the AKT pathway. Inhibition of the AKT pathway diminished the protective effects of MIF in the in vitro study.

CONCLUSIONS

We demonstrated that EPC-CM protected the brain from chronic ischemic injury and promoted functional recovery through MIF-mediated AKT pathway. These findings suggest EPC-CM holds potential as a novel cell-free therapeutic approach for treating CCI through the actions of MIF.

Macrophage migration inhibitory factor (MIF) in CNS diseases: Functional regulation and potential therapeutic indication

Macrophage migration inhibitory factor (MIF) is a multifunctional protein that possesses cytokine, enzyme, and endocrine activities and acts as a chaperone-like molecule. Owing to its immune-inflammatory regulatory properties, the role of MIF has long been an attractive target in research on various autoimmune and inflammatory disorders. MIF is also widely expressed in the central nervous system (CNS), and its potential roles in CNS disorders have become a focus to elucidate the physiological and pathological effects of MIF and to explore its potential significance in the treatment of CNS diseases. Previously, the majority of work on MIF functional regulation was focused on MIF tautomerase inhibitors. However, mounting information has indicated that the functions of MIF extend far beyond its tautomerase activity. Here, we review the recent advances in understanding the complex roles of MIF in the pathogenesis of CNS disorders as well as the discovery and design of small molecules targeted to tautomerase and nuclease of MIF.

HIF-1α promotes astrocytic production of macrophage migration inhibitory factor following spinal cord injury

BACKGROUND

Macrophage migration inhibitory factor (MIF) is an important mediator of neuropathology in various central nervous system (CNS) diseases. However, little is known about its inducers for production from the nerve cells, as well as the underlying regulatory mechanism. Injury-induced HIF-1α has been shown to exacerbate neuroinflammation by activating multiple downstream target molecules. It is postulated that HIF-1α is involved in the regulation of MIF following spinal cord injury (SCI).

METHODS

SCI model of Sprague-Dawley rats was established by cord contusion at T8-T10. The dynamic changes of HIF-1α and MIF protein levels at lesion site of rat spinal cord were determined by Western blot. The specific cell types of HIF-1α and MIF expression were examined by immunostaining. Primary astrocytes were isolated from the spinal cord, cultured and stimulated with various agonist or inhibitor of HIF-1α for analysis of HIF-1α-mediated expression of MIF. Luciferase report assay was used to determine the relationship between HIF-1α and MIF. The Basso, Beattie, and Bresnahan (BBB) locomotor scale was used to assess the locomotor function following SCI.

RESULTS

The protein levels of HIF-1α and MIF at lesion site were significantly elevated by SCI. Immunofluorescence demonstrated that both HIF-1α and MIF were abundantly expressed in the astrocytes of the spinal cord. By using various agonists or inhibitors of HIF-1α, it was shown that HIF-1α sufficiently induced astrocytic production of MIF. Mechanistically, HIF-1α promoted MIF expression through interaction with MIF promoter. Inhibition of HIF-1α activity using specific inhibitor markedly reduced the protein levels of MIF at lesion site following SCI, which in turn favored for the functional recovery.

CONCLUSION

SCI-induced activation of HIF-1α is able to promote MIF production from astrocytes. Our results have provided new clues for SCI-induced production of DAMPs, which may be helpful for clinical treatment of neuroinflammation.

Dualistic roles and mechanistic insights of macrophage migration inhibitory factor in brain injury and neurodegenerative diseases

Macrophage migration inhibitory factor (MIF) is involved in various immune-mediated pathologies and regulates both innate and adaptive immune reactions, thus being related to several acute and chronic inflammatory diseases such as rheumatoid arthritis, septic shock, and atherosclerosis. Its role in acute and chronic brain pathologies, such as stroke and neurodegenerative diseases, has attracted increasing attention in recent years. In response to stimuli like hypoxia, inflammation or infection, different cell types can rapidly release MIF, including immune cells, endothelial cells, and neuron cells. Notably, clinical data from past decades also suggested a possible link between serum MIF levels and the severity of stroke and the evolving of neurodegenerative diseases. In this review, we summarize the major and recent findings focusing on the mechanisms of MIF modulating functions in brain injury and neurodegenerative diseases, which may provide important therapeutic targets meriting further investigation.

The relevance of serum macrophage migratory inhibitory factor and cognitive dysfunction in patients with cerebral small vascular disease

Cerebral small vascular disease (CSVD) is a common type of cerebrovascular disease, and an important cause of vascular cognitive impairment (VCI) and stroke. The disease burden is expected to increase further as a result of population aging, an ongoing high prevalence of risk factors (e.g., hypertension), and inadequate management. Due to the poor understanding of pathophysiology in CSVD, there is no effective preventive or therapeutic approach for CSVD. Macrophage migration inhibitory factor (MIF) is a multifunctional cytokine that is related to the occurrence and development of vascular dysfunction diseases. Therefore, MIF may contribute to the pathogenesis of CSVD and VCI. Here, reviewed MIF participation in chronic cerebral ischemia-hypoperfusion and neurodegeneration pathology, including new evidence for CSVD, and its potential role in protection against VCI.

Rehabilitation Training Can Significantly Increase the Serum IL-11 Levels and Improve the Prognosis in Ischemic Stroke Patients

We aimed to explore the expression of IL-11 in ischemic stroke patients and its correlation with rehabilitation training and prognosis. The present randomized control study recruited ischemic stroke patients who were admitted during March 2014 to November 2020. All patients underwent computer tomography (CT) and magnetic resonance imaging (MRI) examination. All patients were randomly divided into two groups, including rehabilitation training (RT) group and control group. The patients in the RT group were received rehabilitation training within 2 days after the vital signs were stable while control group received routine nursing. The serum interleukin- (IL-) 11 levels were measured by enzyme-linked immunosorbent assay (ELISA) when patients were just hospitalized and 6 h, 24 h, 48 h, 72 h, and 90 h after treatment. Demographic, clinical statistics, imaging data, and the National Institutes of Health Stroke Scores (NIHSS) were recorded. The modified Rankin Scale (mRS) scores were measured after 90 days treatment to assess the prognosis of ischemic patients. The serum IL-11 levels of the RT group elevated more quickly during the study time compared with the control group. In addition, the NIHSS and mRS scores of ischemic stroke patients in the RT group were significantly lower than that in the control group. The NIHSS score, the proportion receiving rehabilitation training, and the levels of IL-11, triglyceride (TG), and high-density leptin cholesterol (HDLC) of ischemic stroke patients in the mRS score ≥ 3 group were remarkably elevated than that in the mRS score ≤ 2 group. However, the serum IL-11 levels of ischemic stroke patients were obviously decreased in the mRS score ≥ 3 group. IL-11 could be a potential diagnostic biomarker of poor prognosis of ischemic stroke patients. Furthermore, IL-11, NIHSS score, and rehabilitation training were the risk factors for poor prognosis of ischemic stroke patients. This study demonstrated that the ischemic stroke patients in the RT group had higher serum IL-11 levels and better prognosis. This study might provide a new approach to improve the prognosis of patients with ischemic stroke. This trial is registered with ChiCTR-PNR-16007706.

Neuroprotective Effect of Macrophage Migration Inhibitory Factor (MIF) in a Mouse Model of Ischemic Stroke

The mechanism of the neuroprotective effect of the macrophage migration inhibitory factor (MIF) in vivo is unclear. We investigated whether the MIF promotes neurological recovery in an in vivo mouse model of ischemic stroke. Transient middle cerebral artery occlusion (MCAO) surgery was performed to make ischemic stroke mouse model. Male mice were allocated to a sham vehicle, a sham MIF, a middle cerebral artery occlusion (MCAO) vehicle, and MCAO+MIF groups. Transient MCAO (tMCAO) was performed in the MCAO groups, and the vehicle and the MIF were administered via the intracerebroventricular route. We evaluated the neurological functional scale, the rotarod test, and T2-weighted magnetic resonance imaging. The expression level of the microtubule-associated protein 2 (MAP2), Bcl2, and the brain-derived neurotrophic factor (BDNF) were further measured by Western blot assay. The Garcia test was significantly higher in the MCAO+MIF group than in the MCAO+vehicle group. The MCAO+MIF group exhibited significantly better performance on the rotarod test than the MCAO+vehicle group, which further had a significantly reduced total infarct volume on T2-weighted MRI imaging than the MCAO vehicle group. Expression levels of BDNF, and MAP2 tended to be higher in the MCAO+MIF group than in the MCAO+vehicle group. The MIF exerts a neuroprotective effect in an in vivo ischemic stroke model. The MIF facilitates neurological recovery and protects brain tissue from ischemic injury, indicating a possibility of future novel therapeutic agents for stroke patients.

Determining the Optimal Administration Conditions under Which MIF Exerts Neuroprotective Effects by Inducing BDNF Expression and Inhibiting Apoptosis in an In Vitro Stroke Model

Macrophage migration inhibitory factor (MIF) exerts neuroprotective effects against cerebral ischemia/reperfusion injury by inhibiting neuronal apoptosis and inducing the expression of brain-derived neurotrophic factor (BDNF). However, the optimal administration conditions of MIF are currently unknown. Here, we aimed to identify these conditions in an in vitro model. To determine the optimal concentration of MIF, human neuroblastoma cells were assigned to one of seven groups: control, oxygen and glucose deprivation/reperfusion (OGD/R), and OGD/R with different concentrations (1, 10, 30, 60, and 100 ng/mL) of MIF. Six groups were studied to investigate the optimal administration time: control, OGD/R, and OGD/R with MIF administered at different times (pre-OGD, OGD-treat, post-OGD, and whole-processing). Water-soluble tetrazolium salt-1 assay, Western blot analysis, and immunocytochemistry were used to analyze cell viability and protein expression. We found that 60 ng/mL was the optimal concentration of MIF. However, the effects of administration time were not significant; MIF elicited similar neuroprotective effects regardless of administration time. These findings correlated with the expression of BDNF and apoptosis-related proteins. This study provides detailed information on MIF administration, which offers a foundation for future in vivo studies and translation into novel therapeutic strategies for ischemic stroke.

Utility of serum macrophage migration inhibitory factor as a potential biomarker for detection of cerebrocardiac syndrome following severe traumatic brain injury

BACKGROUND

Cerebrocardiac syndrome (CCS) is a common complication after severe traumatic brain injury (sTBI) and its occurrence obviously increases the risk of a poor outcome. Macrophage migration inhibitory factor (MIF) acts as an inflammatory cytokine and its circulating concentration are related to acute heart and brain injury. The aim of this study was to examine the association of serum concentration of MIF with posttraumatic CCS.

METHODS

From January 2016 to February 2019, 116 sTBI patients and 116 healthy controls with similar age and gender percentage were recruited. Relationship between serum MIF concentration and CCS was assessed using multivariate analysis.

RESULTS

Serum MIF concentration of patients were significantly higher than those among controls. Serum MIF concentration were intimately correlated with Glasgow coma scale scores (t = -5.553, P < 0.001) and serum C-reactive protein concentration (t = 5.320, P < 0.001) in a multivariate linear regression model. 61 patients (52.6%) displayed CCS. Under ROC curve analylsis, there was a strong discriminatory ability for CCS regarding serum MIF concentration (area under curve, 0.834; 95% confidence interval, 0.754-0.897). Serum MIF concentration were highly associated with CCS independent of other confounding factors (odds ratio, 5.608; 95% CI: 1.896-16.587).

CONCLUSIONS

Increased MIF in serum may be a useful biomarker for early detection of CCS after head trauma.

Monocyte Transmodulation: The Next Novel Therapeutic Approach in Overcoming Ischemic Stroke?

The immune response following neuroinflammation is a vital element of ischemic stroke pathophysiology. After the onset of ischemic stroke, a specialized vasculature system that effectively protects central nervous system tissues from the invasion of blood cells and other macromolecules is broken down within minutes, thereby triggering the inflammation cascade, including the infiltration of peripheral blood leukocytes. In this series of processes, blood-derived monocytes have a significant effect on the outcome of ischemic stroke through neuroinflammatory responses. As neuroinflammation is a necessary and pivotal component of the reparative process after ischemic stroke, understanding the role of infiltrating monocytes in the modulation of inflammatory responses may offer a great opportunity to explore new therapies for ischemic stroke. In this review, we discuss and highlight the function and involvement of monocytes in the brain after ischemic injury, as well as their impact on tissue damage and repair.

Antagonism of Macrophage Migration Inhibitory Factory (MIF) after Traumatic Brain Injury Ameliorates Astrocytosis and Peripheral Lymphocyte Activation and Expansion

Traumatic brain injury (TBI) precedes the onset of epilepsy in up to 15–20% of symptomatic epilepsies and up to 5% of all epilepsy. Treatment of acquired epilepsies, including post-traumatic epilepsy (PTE), presents clinical challenges, including frequent resistance to anti-epileptic therapies. Considering that over 1.6 million Americans present with a TBI each year, PTE is an urgent clinical problem. Neuroinflammation is thought to play a major causative role in many of the post-traumatic syndromes, including PTE. Increasing evidence suggests that neuroinflammation facilitates and potentially contributes to seizure induction and propagation. The inflammatory cytokine, macrophage migration inhibitory factor (MIF), is elevated after TBI and higher levels of MIF correlate with worse post-traumatic outcomes. MIF was recently demonstrated to directly alter the firing dynamics of CA1 pyramidal neurons in the hippocampus, a structure critically involved in many types of seizures. We hypothesized that antagonizing MIF after TBI would be anti-inflammatory, anti-neuroinflammatory and neuroprotective. The results show that administering the MIF antagonist ISO1 at 30 min after TBI prevented astrocytosis but was not neuroprotective in the peri-lesion cortex. The results also show that ISO1 inhibited the TBI-induced increase in γδT cells in the gut, and the percent of B cells infiltrating into the brain. The ISO1 treatment also increased this population of B cells in the spleen. These findings are discussed with an eye towards their therapeutic potential for post-traumatic syndromes, including PTE.

Macrophage Migration Inhibitory Factor Alters Functional Properties of CA1 Hippocampal Neurons in Mouse Brain Slices

Neuroinflammation is implicated in a host of neurological insults, such as traumatic brain injury (TBI), ischemic stroke, Alzheimer's disease, Parkinson's disease, and epilepsy. The immune response to central nervous system (CNS) injury involves sequelae including the release of numerous cytokines and chemokines. Macrophage migration inhibitory factor (MIF), is one such cytokine that is elevated following CNS injury, and is associated with the prognosis of TBI, and ischemic stroke. MIF has been identified in astrocytes and neurons, and some of the trophic actions of MIF have been related to its direct and indirect actions on astrocytes. However, the potential modulation of CNS neuronal function by MIF has not yet been explored. This study tests the hypothesis that MIF can directly influence hippocampal neuronal function. MIF was microinjected into the hippocampus and the genetically encoded calcium indicator, GCaMP6f, was used to measure Ca²⁺ events in acute adult mouse brain hippocampal slices. Results demonstrated that a single injection of 200 ng MIF into the hippocampus significantly increased baseline calcium signals in CA1 pyramidal neuron somata, and altered calcium responses to N-methyl-d-aspartate (NMDA) + D-serine in pyramidal cell apical dendrites located in the stratum radiatum. These data are the first to show direct effects of MIF on hippocampal neurons and on NMDA receptor function. Considering that MIF is elevated after brain insults such as TBI, the data suggest that, in addition to the previously described role of MIF in astrocyte reactivity, elevated MIF can have significant effects on neuronal function in the hippocampus.

The Association Between Serum Macrophage Migration Inhibitory Factor and Delayed Cerebral Ischemia After Aneurysmal Subarachnoid Hemorrhage

Inflammatory processes have long been implicated in the development of delayed cerebral ischemia (DCI) following aneurysmal subarachnoid hemorrhage (aSAH). Macrophage migration inhibitory factor (MIF) has been implicated in inflammation. The aim of this study was to assess whether serum levels of MIF at admission helps to predict which patients with aSAH would subsequently develop DCI. All patients with first-ever aSAH admitted between 2016 and 2017 were considered for inclusion in this prospective study. Primary study outcome was development of DCI at discharge. Serum levels of MIF, C-reactive protein (CRP), and interleukin-6 (IL-6) were tested at admission. The relation of serum levels of MIF at admission with DCI was assessed by the logistic regression models. In this study, 201 patients were included. A correlation between Hunt and Hess score and serum levels of MIF was found (r = 0.340; P < 0.001). Fifty-two of the 201 aSAH (25.9%) were defined as DCI, and the obtained MIF level in those patients was higher than in those patients without DCI [26.4 (IQR, 22.6-32.4) ng/ml vs. 20.4 (16.4-24.6) ng/ml; P < 0.001). As a continuous variable, MIF was associated with the risk of DCI. When serum level of MIF was elevated by each 1 ng/ml, the unadjusted risk of DCI was increased by 18% (OR = 1.18 [1.12-1.25], P < 0.001), while the adjusted risk was increased by 10% (1.10 [1.03-1.19], P = 0.001). With the area under the curve (AUC) of 0.780 (95% CI, 0.710-0.849), the MIF showed a great discriminatory ability for DCI than CRP (0.665, 0.582-0.748; P < 0.001) and IL-6 (0.721, 0.642-0.799; P = 0.001). Interestingly, the combined model (MIF/IL-6/CRP) improved the MIF to predict DCI (AUC of the combined model: 0.811; 95% CI, 0.751-0.871; P = 0.024). Furthermore, inclusion of MIF in the existing risk factors for the prediction of DCI enhanced the index and net reclassification improvement (NRI) (P < 0.001) and integrated discrimination improvement (IDI) (P = 0.005) values, confirming the effective reclassification and discrimination. The data showed that elevated MIF serum level accurately identifies patients at highest risk for developing DCI following aSAH.

Stroke Dysbiosis Index (SDI) in Gut Microbiome Are Associated With Brain Injury and Prognosis of Stroke

Background: Significant dysbiosis occurs in the gut microbiome of stroke patients. Condensing these broad, complex changes into one index would greatly facilitate the clinical usage of gut microbiome data. Here, we formulated a gut microbiota index in patients with acute ischemic stroke based on their gut microbiota dysbiosis patterns and tested whether the index was correlated with brain injury and early outcome.

Methods: A total of 104 patients with acute ischemic stroke and 90 healthy individuals were recruited, and their gut microbiotas were compared and to model a Stroke Dysbiosis Index (SDI), which representing stroke-associated dysbiosis patterns overall. Another 83 patients and 70 controls were recruited for validation. The association of SDI with stroke severity (National Institutes of Health Stroke Scale [NIHSS] score) and outcome (modified Rankin scale [mRS] score: favorable, 0–2; unfavorable, >2) at discharge was also assessed. A middle cerebral artery occlusion (MCAO) model was used in human flora-associated (HFA) animals to explore the causal relationship between gut dysbiosis and stroke outcome.

Results: Eighteen genera were significantly different between stroke patients and healthy individuals. The SDI formula was devised based on these microbiome differences; SDI was significantly higher in stroke patients than in healthy controls. SDI alone discriminated stroke patients from controls with AUCs of 74.9% in the training cohort and 84.3% in the validation cohort. SDI was significantly and positively correlated with NIHSS score on admission and mRS score at discharge. Logistic regression analysis showed that SDI was an independent predictor of severe stroke (NIHSS ≥8) and early unfavorable outcome (mRS >2). Mice receiving fecal transplants from high-SDI patients developed severe brain injury with elevated IL-17⁺ γδ T cells in gut compared to mice receiving transplants from low-SDI patients (all P < 0.05).

Conclusions: We developed an index to measure gut microbiota dysbiosis in stroke patients; this index was significantly correlated with patients' outcome and was causally related to outcome in a mouse model of stroke. Our model facilitates the potential clinical application of gut microbiota data in stroke and adds quantitative evidence linking the gut microbiota to stroke.