Cerebrovascular Permeability Research Articles

Traumatic brain injury (TBI) is a significant cause of death and disability, affecting nearly 300,000 Americans annually. Beyond the immediate physical damage, TBI induces chronic neuroinflammation and long-term neurodegeneration, leading to various neurologic and psychiatric disorders. This review examines the cerebrovascular unit (CVU), particularly the cerebral endothelial cells, and their critical role in the aftermath of TBI. Following TBI, the CVU undergoes functional changes to counteract inflammation, repair endothelial damage, and promote angiogenesis. However, dysregulation of these protective mechanisms can lead to chronic neuroinflammation, increased cerebrovascular permeability, and systemic endothelial dysfunction. The review explores the molecular and cellular responses of the CVU following TBI, highlighting the roles of inflammatory cytokines, oxidative stress, and various endothelial transport mechanisms. Moreover, TBI-related endothelial dysfunction may extend beyond the brain, potentially contributing to systemic complications such as acute respiratory distress syndrome (ARDS) and multisystem organ failure. Despite the gravity of these conditions, clinical breakthroughs remain limited. This review underscores the necessity for targeted therapeutic strategies to mitigate endothelial dysfunction and improve long-term outcomes for TBI patients. Future research is essential to elucidate the precise mechanisms driving CVU dysfunction and to develop interventions that can alleviate the chronic effects of TBI.

INTRODUCTIONPlacental growth factor (PlGF) may regulate cerebrovascular permeability. We hypothesized that white matter interstitial fluid accumulation, estimated via magnetic resonance imaging (MRI) free water (FW), would explain the associations between elevated PlGF, white matter hyperintensities (WMH), and cognitive impairment.METHODSMarkVCID consortium participants ≥55 years old with plasma PlGF and brain MRI were included. We tested cross‐sectionally whether FW mediated the associations between PlGF and WMH, or PlGF and cognition, measured using the Clinical Dementia Rating (CDR) scale and an executive function (EF) composite (Uniform Data Set version 3 [UDS3]‐EF).RESULTSFor 370 participants (mean age 72), a higher PlGF was associated with higher FW, higher WMH, and higher CDR, but not UDS3‐EF. Higher FW was associated with higher WMH, higher CDR, and lower UDS3‐EF. FW explained 26% of the association between PlGF and CDR and 73% of the association between PlGF and WMH.DISCUSSIONElevated PlGF may contribute to WMH and cognitive impairment through white matter FW accumulation.CLINICAL TRIAL REGISTRATIONNCT06284213HighlightsPlGF is a promising blood‐based biomarker for vascular cognitive impairment.In MarkVCID, higher PlGF was associated with accumulated white matter FW on MRI.FW mediated the association between higher PlGF and MRI‐visible white matter injury.FW mediated the association between PlGF and worse CDR scale.PlGF may contribute to cognitive dysfunction via accumulated interstitial fluid.

Vascular contribution to cognitive impairment and dementia (VCID) is a term referring to all types of cerebrovascular and cardiovascular disease-related cognitive decline, spanning many neuroinflammatory diseases including traumatic brain injury (TBI). This becomes particularly important during mild-to-moderate TBI (m-mTBI), which is characterized by short-term memory (STM) decline. Enhanced cerebrovascular permeability for proteins is typically observed during m-mTBI. We have previously shown that an increase in the blood content of fibrinogen (Fg) during m-mTBI results in enhanced cerebrovascular permeability. Primarily extravasated via a transcellular pathway, Fg can deposit into the parenchyma and exacerbate inflammatory reactions that can lead to neurodegeneration, resulting in cognitive impairment. In the current study, we investigated the effect of a chronic reduction in Fg concentration in blood on cerebrovascular permeability and the interactions of extravasated Fg with astrocytes and neurons. Cortical contusion injury (CCI) was used to generate m-mTBI in transgenic mice with a deleted Fg γ chain (Fg γ+/-), resulting in a low blood content of Fg, and in control C57BL/6J wild-type (WT) mice. Cerebrovascular permeability was tested in vivo. Interactions of Fg with astrocytes and neurons and the expression of neuronal nuclear factor-кB (NF-кB) were assessed via immunohistochemistry. The results showed that 14 days after CCI, there was less cerebrovascular permeability, lower extravascular deposition of Fg, less activation of astrocytes, less colocalization of Fg with neurons, and lower expression of neuronal pro-inflammatory NF-кB in Fg γ+/- mice compared to that found in WT mice. Combined, our data provide strong evidence that increased Fg extravasation, and its resultant extravascular deposition, triggers astrocyte activation and leads to potential interactions of Fg with neurons, resulting in the overexpression of neuronal NF-кB. These effects suggest that reduced blood levels of Fg can be beneficial in mitigating the STM reduction seen in m-mTBI.

Alzheimer's disease (AD) is a prevalent neurodegenerative disorder characterized by progressive neuronal damage and cognitive decline. Recent studies have shed light on the involvement of not only the blood-brain barrier (BBB) dysfunction but also significant alterations in cellular junctions in AD pathogenesis. In this review article, we explore the role of the BBB and cellular junctions in AD pathology, with a specific focus on the hippocampus. The BBB acts as a crucial protective barrier between the bloodstream and the brain, maintaining brain homeostasis and regulating molecular transport. Preservation of BBB integrity relies on various junctions, including gap junctions formed by connexins, tight junctions composed of proteins such as claudins, occludin, and ZO-1, as well as adherence junctions involving molecules like vascular endothelial (VE) cadherin, Nectins, and Nectin-like molecules (Necls). Abnormalities in these junctions and junctional components contribute to impaired neuronal signaling and increased cerebrovascular permeability, which are closely associated with AD advancement. By elucidating the underlying molecular mechanisms governing BBB and cellular junction dysfunctions within the context of AD, this review offers valuable insights into the pathogenesis of AD and identifies potential therapeutic targets for intervention.

Abstract BackgroundFibrinogen is not only a marker of inflammation, but also a cause of inflammatory responses. We previously showed that when elevated during traumatic brain injury (TBI), fibrinogen increased cerebrovascular permeability mainly via caveolar transcytosis and, after extravasation and deposition in vasculo‐astrocyte interface, it activated astrocytes causing neurodegeneration that was associated with memory reduction.MethodTo define the possible mechanisms of fibrinogen‐induced activation of neurons, primary mouse brain cortical neurons from C57BL/6 mice were plated in poly‐d‐lysine‐ and laminin‐coated cell culture plates. Cells were treated for 1 hour with fibrinogen (0.5 or 1 mg/mL) in the presence or absence of a nuclear factor‐κB (NF‐kB) blocker, caffeic acid phenethyl ester (CAPE), or media alone (control). All groups contained hirudin to prevent the conversion of fibrinogen to fibrin. Levels of interleukin‐6 (IL‐6) and chemokine (C‐C motif) ligand 2 (CCL2) were assessed by qRT‐PCR. NF‐kB activity was measured in neuronal nuclear protein and cell extracts by the TransAMTM NF‐kB p65 protein assay and Western blot (WB). In parallel, using a cortical contusion injury (CCI), a mouse model of mild‐to‐moderate TBI was created in C576J mice. NF‐kB was detected with immunocytochemistry in cultured cells and brain samples collected 14 days after CCI. The specific association of fibrinogen with its neuronal receptors intercellular adhesion molecule‐1 (ICAM‐1) and cellular prion protein (PrPC) was assessed with a proximity ligation assay in cells.ResultFibrinogen specifically bound to neurons via its receptors ICAM‐1 and PrPC and increased NF‐kB levels. Fibrinogen caused upregulation of pro‐inflammatory cytokines IL‐6 and CCL2 mRNA. ELISA and WB NF‐kB p65 analysis demonstrated increased DNA binding by p65 and protein expression in fibrinogen‐treated neurons compared to that in control and CAPE groups. Fibrinogen caused translocation of NF‐kB p65 to the nucleus.ConclusionResults suggest that a specific interaction of fibrinogen with neurons results in neuroinflammation through activation of NF‐kB.

Drug discovery for stroke is challenging as indicated by poor clinical translatability. In contrast, HMG-CoA (3-hydroxy-3-methylglutaryl coenzyme A) reductase inhibitors (ie, statins) improve poststroke neurological outcomes. This property requires transport across the blood-brain barrier via an endogenous uptake transporter (ie, Oatp1a4 [organic anion transporting polypeptide 1a4]). Our goal was to study Oatp1a4 as a drug delivery mechanism because the blood-brain barrier cannot be assumed to be completely open for all drugs in ischemic stroke. Male Sprague-Dawley rats (200-250 g) were subjected to middle cerebral artery occlusion (90 minutes) followed by reperfusion for up to 7 days. Atorvastatin (20 mg/kg, IV) was administered 2 hours following intraluminal suture removal. Involvement of Oatp-mediated transport was determined using fexofenadine (3.2 mg/kg, IV), a competitive Oatp inhibitor. Oatp1a4 transport activity was measured by in situ brain perfusion. Infarction volumes/brain edema ratios and neuronal nuclei expression were determined using 2,3,5-triphenyltetrazolium chloride-stained brain tissue slices and confocal microscopy, respectively. Poststroke functional outcomes were assessed via neurological deficit scores and rotarod analysis. At 2-hour post-middle cerebral artery occlusion, [3H]atorvastatin uptake was increased in ischemic brain tissue. A single dose of atorvastatin significantly reduced post-middle cerebral artery occlusion infarction volume, decreased brain edema ratio, increased caudoputamen neuronal nuclei expression, and improved functional neurological outcomes. All middle cerebral artery occlusion positive effects of atorvastatin were attenuated by fexofenadine coadministration (ie, an Oatp transport inhibitor). Our data demonstrate that neuroprotective effects of atorvastatin may require central nervous system delivery by Oatp-mediated transport at the blood-brain barrier, a mechanism that persists despite increased cerebrovascular permeability in ischemic stroke. These novel and translational findings support utility of blood-brain barrier transporters in drug delivery for neuroprotective agents.

Lycium barbarum polysaccharide (LBP) is the efficient primary compound of Lycium barbarum and has been shown to alleviate hyperglycemia-aggravated cerebral ischemia/reperfusion (I/R) injury. However, the cerebrovascular changes related to diabetes mellitus (DM) and the potential cerebrovascular protective effects of LBP are still unknown. This study aimed to explore the cerebrovascular protective functions of LBP on cerebral I/R injury in diabetic rats and its potential mechanisms. Sprague Dawley (SD) rats were separated into three groups: the normoglycemic (NG), diabetic hyperglycemic (HG), and HG + LBP (50 mg/kg) treatment groups. A 30 min transient middle cerebral artery occlusion (tMCAO) with 24 h reperfusion was established. The neurological deficits, cerebral water content, infarct volume, and cerebrovascular permeability were assessed to evaluate the extent of cerebral injury. Histopathological alterations were assessed by hematoxylin and eosin, Nissl, immunohistochemical, and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling staining. A transmission electron microscope was used to detect ultrastructural alterations, and a western blot was used to examine protein expression. The HG rats exhibited a significant increase in neurological deficits, cerebral water content, infarct volume, cerebrovascular permeability, neural cell death, and apoptosis compared with the NG rats, and the LBP treatment alleviated these effects. Cerebrovascular structure analysis showed that the cross-sectional area (CSA) and wall thickness were remarkably altered in the HG rats compared with the NG rats. The LBP treatment protected the cerebrovascular structure and vasoreactivity by decreasing the wall thickness and increasing the CSA, α-smooth muscle actin, and endothelial nitric oxide synthase expression of cerebral vessels. The intake of LBP benefits the cerebrovascular structure and vasoreactivity in diabetic rats. Our research provides a possible new strategy for treating stroke in patients with DM.

Tumor necrosis factor-like weak inducer of apoptosis (TWEAK) is a member of the TNF ligand family involved in various diseases including brain inflammatory pathologies such as multiple sclerosis. It has been demonstrated that TWEAK can induce cerebrovascular permeability in an in vitro model of the blood–brain barrier. The molecular mechanisms playing a role in TWEAK versus TNFα signaling on cerebral microvascular endothelial cells are not well defined. Therefore, we aimed to identify gene expression changes in cultures of human brain microvascular endothelial cells (hCMEC/D3) to address changes initiated by TWEAK exposure. Taken together, our studies highlighted that gene involved in leukocyte extravasation, notably claudin-5, were differentially modulated by TWEAK and TNFα. We identified differential gene expression of hCMEC/D3 cells at three timepoints following TWEAK versus TNFα stimulation and also found distinct modulations of several canonical pathways including the actin cytoskeleton, vascular endothelial growth factor (VEGF), Rho family GTPases, and phosphatase and tensin homolog (PTEN) pathways. To our knowledge, this is the first study to interrogate and compare the effects of TWEAK versus TNFα on gene expression in brain microvascular endothelial cells.

Thrombolytic tPA-induced hemorrhagic transformation of ischemic stroke is mediated by PKCβ phosphorylation of occludin

The loss function of cerebral cavernous malformation (CCM) genes leads to most CCM lesions characterized by enlarged leaking vascular lesions in the brain. Although we previously showed that NOGOB receptor (NGBR) knockout in endothelial cells (ECs) results in cerebrovascular lesions in the mouse embryo, the molecular mechanism by which NGBR regulates CCM1/2 expression has not been elucidated. Here, we show that genetic depletion of Ngbr in ECs at both postnatal and adult stages results in CCM1/2 expression deficiency and cerebrovascular lesions such as enlarged vessels, blood-brain-barrier hyperpermeability, and cerebral hemorrhage. To reveal the molecular mechanism, we used RNA-sequencing analysis to examine changes in the transcriptome. Surprisingly, we found that the acetyltransferase HBO1 and histone acetylation were downregulated in NGBR-deficient ECs. The mechanistic studies elucidated that NGBR is required for maintaining the expression of CCM1/2 in ECs via HBO1-mediated histone acetylation. ChIP-qPCR data further demonstrated that loss of NGBR impairs the binding of HBO1 and acetylated histone H4K5 and H4K12 on the promotor of the CCM1 and CCM2 genes. Our findings on epigenetic regulation of CCM1 and CCM2 that is modulated by NGBR and HBO1-mediated histone H4 acetylation provide a perspective on the pathogenesis of sporadic CCMs.

Over 69 million traumatic brain injuries (TBIs) are reported annually worldwide, where the geriatric population are at greatest risk for prolonged morbidity and mortality. Cerebrovascular aging contributes to this increased vulnerability through extracellular matrix (ECM) impairment, vascular wall weakening and stiffening, blood‐brain barrier (BBB) permeability, and exacerbated cytokine production, yet the mechanisms behind these contributions are minimally investigated. In order to study these targets efficiently and with minimal variability, an animal model presenting these cerebrovascular alterations is required. Fibrillin‐1 (Fbn1) protein plays a role in elasticity and inflammation, and its mutation is known to lead to ECM impairment and vessel wall weakening induced by increased availability in transforming growth factor‐b (TGF‐b) and downstream production of matrix metalloproteinases (MMPs)‐2/‐9. In mice, this mutation induces vascular dysfunction by 6M of age and is a well‐established model of Marfan Syndrome.In this study, Fbn1+/‐ were utilized to test the hypothesis that Fbn1 mutation accelerates cerebrovascular rigidity, BBB permeability, and neurological alterations associated with aging, leaving the brain more vulnerable to diffuse TBI. In 6M‐ and 12M‐old Fbn1+/‐ and C57BL/6 wildtype (WT) male and female mice, posterior cerebral artery (PCA) blood flow (n=8‐10), PCA rupture point (N=3‐5/group), BBB permeability (N=2‐3/group), injury viability (N=5‐8/group), neurobehavioral severity scale (NSS) outcomes (N=10‐11/group), and microglial perturbation (N=1/group) were assessed.Our data shows that 6M‐old Fbn1+/‐ mice have decreased PCA blood flow (p<0.05), compromised PCA wall strength (p<0.05), increased BBB permeability (p<0.05), and elevated NSS scores (p<0.05) as compared to 6M‐old WT, and similar to 12M‐old WT mice. Preliminary investigation of iba‐1 staining for microglia, a supported assessment of neuroinflammation, suggests increased microglial activation in 6M‐old Fbn1+/‐ mice compared to age‐matched WT mice. To investigate vulnerability to mild TBI (mTBI), varying pulse pressures (1.11‐1.32atm) were applied to the brains of 6M‐old WT (1.25‐1.32atm) and Fbn1+/‐ (1.17‐1.21atm) mice using midline fluid percussion injury, where Fbn1+/‐ mice required lowered pressure to induce mTBI righting reflex times (5‐10 minutes).These data support that cerebrovascular aging contributes to outcome after TBI. Furthermore, this study demonstrates that Fbn1 mutation plays a critical role in the vulnerability of the aged brain to mTBI. Using this novel approach of a Marfan Syndrome mouse model that isolates cerebrovascular aging allows for the mechanistic study of potential Fbn1 downstream pathways that could serve as a therapeutic target for prevention and management of post‐concussive symptoms.

Acute ischemic stroke (AIS) triggers endothelial activation and induces cerebrovascular inflammation which can result in vascular integrity loss leading to worsened stroke outcome. A clinically correlated risk factor for stroke shown to mediate vascular injury is elevated levels of oxidized low‐density lipoprotein (OxLDL). Via the lectin‐like OxLDL receptor 1 (LOX‐1), OxLDL contributes to mechanisms associated with vascular dysfunction and inflammation. The impact of OxLDL/LOX‐1 on cerebrovascular endothelial dysfunction and inflammation in the setting of AIS remains to be elucidated. The aim of this study is to investigate the effect of OxLDL via LOX‐1 on endothelial proinflammatory mediator and integral barrier protein levels during in vitro ischemic‐like conditions. We hypothesized that acute ischemic injury would increase endothelial barrier dysfunction as well as inflammation and that OxLDL would exacerbate these responses in a LOX‐1 dependent manner. Primary male human brain microvascular endothelial cells (HBMEC) were preconditioned with human OxLDL (50μg/dL; 12h) or vehicle using a serum dose reported in AIS patients. Next cells were treated with BI‐0115 (selective LOX‐1 inhibitor; 10μM) or vehicle (<0.1% DMSO) for 0.5h prior to being exposed to normoxia (21% O2) or hypoxia plus glucose deprivation (HGD; 1% O2) for 6h in the continued presence of OxLDL or vehicle. Levels of HBMEC barrier protein (ZO‐1), adhesion molecule (VCAM‐1), and inflammatory proteins (iNOS, IL‐1β) were examined using FIJI mediated immunocytochemical analysis. In terms of barrier protein levels, we observed that ZO‐1 levels were decreased following HGD. Contrary to our hypothesis, OxLDL plus HGD resulted in increased levels of ZO‐1; and moreover, we observed a greater increase in ZO‐1 levels when treated with BI‐0115 alone or BI‐0115 plus OxLDL. During normoxic conditions OxLDL increased levels of ZO‐1 and this response was LOX‐1 independent. Concomitantly, HGD increased levels of the adhesion molecule, VCAM‐1. The presence of HGD plus OxLDL or OxLDL plus BI‐0115 had no effect on VCAM‐1 expression. During normoxic conditions, OxLDL increased VCAM‐1 levels in a LOX‐1 dependent manner. We next observed that HGD increased the levels of proinflammatory mediators, iNOS and IL‐1β. OxLDL under normoxic conditions significantly increased the levels of iNOS in a LOX‐1 dependent manner but had no effect on the levels of IL‐1β. HGD plus OxLDL had no effect on iNOS levels; however, treatment with BI‐0115 alone or BI‐0115 plus OxLDL significantly attenuated HGD‐mediated increases in iNOS levels. Moreover during HGD, OxLDL increased levels of IL‐1β in a LOX‐1 dependent manner suggesting that OxLDL acting through LOX‐1 leads to an increase in a central mediator of vascular inflammation and permeability. In conclusion, the beneficial effect of LOX‐1 inhibition on cerebrovascular endothelial permeability and inflammation suggests that this receptor may be a novel, viable therapeutic target in the treatment of AIS.

CRH/CRHR1 modulates cerebrovascular endothelial cell permeability in association with S1PR2 and S1PR3 under oxidative stress

The loss of vascular integrity at the level of the blood brain barrier leads to a vicious cascade of secondary injuries following acute ischemic stroke (AIS). Elevated MMP-9 activity within the cerebral vasculature has been implicated with severe degradation of the vascular basement membrane leading to abnormal cerebrovascular permeability and detrimental stroke outcome. Sphingosine-1-phosphate receptor (S1PR) modulation improves stroke outcome in AIS patients, however the influence of selective S1PR1ligands, such as ozanimod, on brain endothelial health and MMP-9 activity following AIS has not been investigated. Thus, the aim of this study was to determine the impact of acute ischemic injury on MMP-9 activity in both the rat and the human cerebrovasculature as well as the vascular specific role of ozanimod on human endothelial health and MMP-9 activity. Using an in vivo thromboembolic stroke model, cerebral vessels were isolated from male Wistar rats that underwent a right middle cerebral artery (MCA) thrombin injection. Sham-operated animals underwent the same surgical procedure; however, nothing was injected. Vascular MMP-9 enzymatic activity of was evaluated at 3, 6 and 24h post injury using zymography. Using an in vitro ischemic injury model (HGD; hypoxia plus glucose deprivation), male human brain microvascular endothelial cells (HBMECs; P7) were treated with ozanimod (0.5nM) or vehicle (DMSO) and then exposed to normoxia (21% O2) or HGD (1% O2). In some experiments, W146 (a selective antagonist), verified S1PR1 dependence. Morphology and vacuole formations were assessed using crystal violet staining. Enzymatic activity of MMP-9 was evaluated via zymography and the extracellular H2O2 concentration, inducer of MMP-9 activity, was measured using a colorimetric assay. Following in vivo thromboembolic occlusion, ipsilateral MMP-9 activity increased at 6h post injury and returned to baseline when compared to sham. In comparison to the contralateral side, thromboembolic occlusion induced a time dependent modulation of ipsilateral MMP-9 activity compared to the contralateral side with the highest activity peaking at 6h. In our in vitro HBMEC stroke model, MMP-9 enzymatic activity was increased following 3h HGD exposure, and this response was attenuated by ozanimod. Concomitantly, during HGD, H2O2 production, a partial inducer of MMP-9 activity, was increased in a time dependent manner when compared to normoxic controls. Furthermore, HGD induced an increase in HBMEC vacuole formations and a decrease in cell viability at 3h. Loss of cell viability was rescued with ozanimod. In conclusion, increased MMP-9 activity, in part due to H2O2, is an acute response to ischemic injury in the cerebrovasculature. Specifically, ozanimod's ability to attenuate endothelial MMP-9 activity may play an important beneficial role in mitigating blood brain barrier integrity loss following an acute ischemic injury.

Endothelium protection is critical, because of the impact of vascular leakage and edema on pathological conditions such as brain ischemia. Whereas deficiency of class II phosphoinositide 3-kinase alpha (PI3KC2α) results in an increase in vascular permeability, we uncover a crucial role of the beta isoform (PI3KC2β) in the loss of endothelial barrier integrity following injury. Here, we studied the role of PI3KC2β in endothelial permeability and endosomal trafficking in vitro and in vivo in ischemic stroke. Mice with inactive PI3KC2β showed protection against vascular permeability, edema, cerebral infarction, and deleterious inflammatory response. Loss of PI3KC2β in human cerebral microvascular endothelial cells stabilized homotypic cell-cell junctions by increasing Rab11-dependent VE-cadherin recycling. These results identify PI3KC2β as a potential new therapeutic target to prevent aggravating lesions following ischemic stroke.

Effectiveness of CAPE in reducing vascular permeability after brain injury

Specialized features of vasculature in the central nervous system greatly limit therapeutic treatment options for many neuropathologies. Focused ultrasound, in combination with circulating microbubbles, can be used to transiently and noninvasively increase cerebrovascular permeability with a high level of spatial precision. For minutes to hours following sonication, drugs can be administered systemically to extravasate in the targeted brain regions and exert a therapeutic effect, after which permeability returns to baseline levels. With the wide range of therapeutic agents that can be delivered using this approach and the growing clinical need, focused ultrasound and microbubble (FUS+MB) exposure in the brain has entered human testing to assess safety. This review outlines the use of FUS+MB-mediated cerebrovascular permeability enhancement as a drug delivery technique, details several technical and biological considerations of this approach, summarizes results from the clinical trials conducted to date, and discusses the future direction of the field.

Hyperhomocysteinemia (HHcy) can be used as an independent risk factor for predicting cardiovascular disease, stroke and vitamin B12 deficiency. Patients with HHcy have elevated plasma homocysteine (Hcy) concentrations. Enhancing cerebrovascular permeability of substances such as Hcy and brain damage will synergistically increase the symptoms of hypertension, but the specific immune regulation mechanism is still not clear. The purpose of the present study was to preliminarily explore the immunomodulatory mechanism of brain damage caused by HHcy in Wistar-Kyoto (WKY) rats. A total of 60 WKYs were randomly divided into three groups: WKY control group (WKY-C group), WKY methionine group (WKY-M group) and WKY treatment group (WKY-T group; vitamin B6, B12 and folic acid were used as treatment), with 20 rats in each group. Physical examination of body weight, systolic blood pressure (SBP) and plasma Hcy content was performed routinely. The concentration of cytokines, including IL-6, IL-10, IL-17A and TGF-β, associated with T helper cell 17 (Th17) and regulatory T (Treg) cells and key regulator genes, including retinoic acid-related orphan receptor γ t (RORγt) and forkhead box P3 (FoxP3), were detected by ELISA, reverse transcription-quantitative PCR and western blotting. Th17/Treg lymphocytes were determined by flow cytometry. MRI scan was preliminarily used to detect the changes characteristic of the ischemic stroke. The results revealed that high methionine diets might have a significant effect on the body weight and SBP. The inflammatory response effect of Treg cells was significantly inhibited in the WKY-M group, and that of Th17 cells was upregulated when compared to the WKY-T group. Compared with the WKY-T group, the expression levels of IL-17A and RORγt in the WKY-M group were significantly upregulated, while the mRNA levels of FoxP3 in the WKY-M group were significantly downregulated. The diet intervention (including vitamins B6 and B12 and folic acid) could reduce the level of Hcy in the blood, but also reduce the inflammatory response and rectify the Treg/Th17 immune imbalance to ameliorate the brain tissue damage. In conclusion, the present study indicated that HHcy can promote inflammation by triggering Treg/Th17 immune imbalance to ameliorate the brain tissue damage.

Effects of fibrinogen synthesis inhibition on vascular cognitive impairment during traumatic brain injury in mice

Differences between normal and diabetic brains in middle-aged rats by MRI