Diabetes mellitus aggravates hemorrhagic transformation after ischemic stroke via mitochondrial defects leading to endothelial apoptosis

Hyperglycemia enhances brain susceptibility to lipopolysaccharide-induced neuroinflammation via astrocyte reprogramming

Hyperglycemia has been shown to modulate the immune response of peripheral immune cells and organs, but the impact of hyperglycemia on neuroinflammation within the brain remains elusive. In the present study, we provide evidences that streptozotocin (STZ)-induced hyperglycemic condition in mice drives a phenotypic switch of brain astrocytes to a proinflammatory state, and increases brain vulnerability to mild peripheral inflammation. In particular, we found that hyperglycemia led to a significant increase in the astrocyte proliferation as determined by flow cytometric and immunohistochemical analyses of mouse brain. The increased astrocyte proliferation by hyperglycemia was reduced by Glut1 inhibitor BAY-876. Transcriptomic analysis of isolated astrocytes from Aldh1l1CreERT2;tdTomato mice revealed that peripheral STZ injection induced astrocyte reprogramming into proliferative, and proinflammatory phenotype. Additionally, STZ-induced hyperglycemic condition significantly enhanced the infiltration of circulating myeloid cells into the brain and the disruption of blood-brain barrier in response to mild lipopolysaccharide (LPS) administration. Systemic hyperglycemia did not alter the intensity and sensitivity of peripheral inflammation in mice to LPS challenge, but increased the inflammatory potential of brain microglia. In line with findings from mouse experiments, a high-glucose environment intensified the LPS-triggered production of proinflammatory molecules in primary astrocyte cultures. Furthermore, hyperglycemic mice exhibited a significant impairment in cognitive function after mild LPS administration compared to normoglycemic mice as determined by novel object recognition and Y-maze tasks. Taken together, these results demonstrate that hyperglycemia directly induces astrocyte reprogramming towards a proliferative and proinflammatory phenotype, which potentiates mild LPS-triggered inflammation within brain parenchymal regions.

MicroRNA Regulatory Pattern in Diabetic Mouse Cortex at Different Stages Following Ischemic Stroke

After ischemic stroke, microRNAs (miRNAs) participate in various processes, including immune responses, inflammation, and angiogenesis. Diabetes is a key factor increasing the risk of ischemic stroke; however, the regulatory pattern of miRNAs at different stages of diabetic stroke remains unclear. This study comprehensively analyzed the miRNA expression profiles in diabetic mice at 1, 3, and 7 days post-reperfusion following the middle cerebral artery occlusion (MCAO). We identified differentially expressed (DE) miRNAs in diabetic stroke and found significant dysregulation of some novel miRNAs (novel_mir310, novel_mir89, and novel_mir396) post-stroke. These DEmiRNAs were involved in apoptosis and the formation of tight junctions. Finally, we identified three groups of time-dependent DE miRNAs (miR-6240, miR-135b-3p, and miR-672-5p). These have the potential to serve as biomarkers of diabetic stroke. These findings provide a new perspective for future research, emphasizing the dynamic changes in miRNA expression after diabetic stroke and offering potential candidates as biomarkers for future clinical applications.

Mitochondrial Dysfunction in Endothelial Progenitor Cells: Unraveling Insights from Vascular Endothelial Cells

Endothelial dysfunction is associated with several lifestyle-related diseases, including cardiovascular and neurodegenerative diseases, and it contributes significantly to the global health burden. Recent research indicates a link between cardiovascular risk factors (CVRFs), excessive production of reactive oxygen species (ROS), mitochondrial impairment, and endothelial dysfunction. Circulating endothelial progenitor cells (EPCs) are recruited into the vessel wall to maintain appropriate endothelial function, repair, and angiogenesis. After attachment, EPCs differentiate into mature endothelial cells (ECs). Like ECs, EPCs are also susceptible to CVRFs, including metabolic dysfunction and chronic inflammation. Therefore, mitochondrial dysfunction of EPCs may have long-term effects on the function of the mature ECs into which EPCs differentiate, particularly in the presence of endothelial damage. However, a link between CVRFs and impaired mitochondrial function in EPCs has hardly been investigated. In this review, we aim to consolidate existing knowledge on the development of mitochondrial and endothelial dysfunction in the vascular endothelium, place it in the context of recent studies investigating the consequences of CVRFs on EPCs, and discuss the role of mitochondrial dysfunction. Thus, we aim to gain a comprehensive understanding of mechanisms involved in EPC deterioration in relation to CVRFs and address potential therapeutic interventions targeting mitochondrial health to promote endothelial function.

Predictors and outcome of early neurological deterioration after endovascular thrombectomy: a secondary analysis of the DIRECT-MT trial

BACKGROUND

There is uncertainty regarding the predictors of early neurological deterioration (END) after endovascular thrombectomy in patients with acute ischemic stroke (AIS). Limited studies have focused on the effect of END on functional outcome. Our aim was to determine the predictors of END after endovascular thrombectomy in AIS and its effect on functional outcome at 90 days.

METHODS

This is a secondary analysis of the DIRECT-MT trial. Patients who failed to complete endovascular thrombectomy were additionally excluded. END was defined as ≥4-point increase in National Institutes of Health Stroke Scale score between admission and 24 hours after endovascular thrombectomy. Multivariable logistic regression was used to identify predictors for END and its effect on the modified Rankin Scale (mRS) score at 90 days.

RESULTS

Of 591 patients enrolled, 111 (18.8%) had postoperative END, which was associated with higher ordinal mRS score at 90 days (adjusted common OR (aOR) 6.968, 95% CI 4.444 to 10.926). Non-modifiable factors included baseline Alberta Stroke Program Early CT Score (aOR 0.883, 95% CI 0.790 to 0.987), systolic blood pressure (aOR 1.017, 95% CI 1.006 to 1.028), glucose level (aOR 1.178, 95% CI 1.090 to 1.273), collateral status (aOR 0.238, 95% CI 0.093 to 0.608), occlusion site (aOR 0.496, 95% CI 0.290 to 0.851) and the presence of an anterior communicating artery (aOR 0.323, 95% CI 0.148 to 0.707). Admission-to-groin puncture time (aOR 1.010, 95% CI 1.003 to 1.017), general anesthesia (aOR 2.299, 95% CI 1.193 to 4.444), number of passes (aOR 1.561, 95% CI 1.243 to 1.961) and contrast extravasation (aOR 6.096, 95% CI 1.543 to 24.088) were modifiable predictors for END.

CONCLUSIONS

Postoperative END is associated with adverse functional outcome. Several non-modifiable and modifiable factors can predict END and support future treatment decision-making to improve the potential utility of endovascular thrombectomy.

TRIAL REGISTRATION NUMBER

DIRECT-MT ClinicalTrials.gov NCT03469206.

Hyperglycemia Aggravates the Cerebral Ischemia Injury via Protein O-GlcNAcylation

BACKGROUND

At least one-third of Alzheimer's disease (AD) patients have cerebrovascular abnormalities, micro- and macro-infarctions, and ischemic white matter alterations. Stroke prognosis impacts AD development due to vascular disease. Hyperglycemia can readily produce vascular lesions and atherosclerosis, increasing the risk of cerebral ischemia. Our previous studies have proved that protein O-GlcNAcylation-a dynamic and reversible post-translational modification, protects against ischemic stroke. However, the role of O-GlcNAcylation in hyperglycemia aggravating cerebral ischemia injury remained unclear.

OBJECTIVE

In the present study, we investigated the role and mechanism of protein O-GlcNAcylation in hyperglycemia exacerbating cerebral ischemia injury.

METHODS

High glucose-cultured brain microvascular endothelial (bEnd3) cells were injured by oxygen-glucose deprivation. Cell viability was used as the assay result. Stroke outcomes and hemorrhagic transformation incidence were assessed in mice after middle cerebral artery occlusion under high glucose and streptozotocin-induced hyperglycemic conditions. Western blot estimated that O-GlcNAcylation influenced apoptosis levels in vitro and in vivo.

RESULTS

In in vitro analyses showed that Thiamet-G induces upregulation of protein O-GlcNAcylation, which attenuates oxygen-glucose deprivation/R-induce injury in bEnd3 cells cultured under normal glucose conditions, while aggravated it under high glucose conditions. In in vivo analyses, Thiamet-G exacerbated cerebral ischemic injury and induced hemorrhagic transformation, accompanied by increased apoptosis. While blocking protein O-GlcNAcylation with 6-diazo-5-oxo-L-norleucine alleviated cerebral injury of ischemic stroke in different hyperglycemic mice.

CONCLUSION

Overall, our study indicates a critical role for O-GlcNAcylation in that hyperglycemia aggravates cerebral ischemia injury. O-GlcNAcylation may be a potential therapeutic drug for ischemic stroke associated with AD.

Association of hypocalcemia with in-hospital mortality in critically ill patients with intracerebral hemorrhage: A retrospective cohort study

Background and purpose

There was little evidence to study the relationship between hypocalcemia and mortality among critically ill patients with intracerebral hemorrhage (ICH) aged ≥16 years. This study aimed to determine the potential association between hypocalcemia and in-hospital and ICU mortality in patients with ICH in the United States.

Methods

We analyzed 1,954 patients with ICH from the e-Intensive Care Unit Collaborative Research Database and divided them into hypocalcemia and non-hypocalcemia groups. Hypocalcemia was defined as albumin-adjusted total calcium below 8.4 mg/dl. The primary and secondary outcomes were hospital and ICU mortality, respectively. We performed multivariable regression and subgroup analyses to evaluate the association of hypocalcemia with hospital and ICU mortality. Cumulative survival rate analysis was performed using Kaplan-Meier curves with log-rank statistics.

Results

We enrolled 1,954 patients with ICH who had been hospitalized in ICU for >24 h and were older than 16 years (average age, 61.8 years; men, 56.7%). We noted that 373 (19%) hospital mortality occurred, including 235 (12%) ICU mortality. In this sample, 195 patients had hypocalcemia. Multivariable logistic regression analyses showed that hypocalcemia was associated with a 67% increased risk of in-hospital and a 72% increased risk of ICU mortality. This association was consistent across subgroup analyses.

Conclusions

Hypocalcemia was associated with a high risk of hospital and ICU mortality among critically ill patients with ICH. Future prospective, randomized, controlled studies are needed to confirm our results.

Central Nervous System Pericytes Contribute to Health and Disease

Successful neuroprotection is only possible with contemporary microvascular protection. The prevention of disease-induced vascular modifications that accelerate brain damage remains largely elusive. An improved understanding of pericyte (PC) signalling could provide important insight into the function of the neurovascular unit (NVU), and into the injury-provoked responses that modify cell–cell interactions and crosstalk. Due to sharing the same basement membrane with endothelial cells, PCs have a crucial role in the control of endothelial, astrocyte, and oligodendrocyte precursor functions and hence blood–brain barrier stability. Both cerebrovascular and neurodegenerative diseases impair oxygen delivery and functionally impair the NVU. In this review, the role of PCs in central nervous system health and disease is discussed, considering their origin, multipotency, functions and also dysfunction, focusing on new possible avenues to modulate neuroprotection. Dysfunctional PC signalling could also be considered as a potential biomarker of NVU pathology, allowing us to individualize therapeutic interventions, monitor responses, or predict outcomes.

Intracellular MUC20 variant 2 maintains mitochondrial calcium homeostasis and enhances drug resistance in gastric cancer

BACKGROUND

Signet ring cell carcinoma (SRCC) is a particular histologic variant of gastric cancer (GC). However, the critical factor related to the aggressive characteristics of SRCC has not been determined.

METHODS

We collected surgically resected tissues from 360 GC patients in the Kumamoto University cohort and generated survival curves via the Kaplan-Meier method. In vitro, we identified the specific transcript variant of MUC20 in SRCC cells by direct sequencing and investigated the role of MUC20 in GC progression using GC cells with MUC20 silencing and forced expression. In vivo, we examined chemoresistance using MUC20 variant 2 (MUC20v2)-overexpressing non-SRCC cells to construct a xenograft mouse model.

RESULTS

We analyzed a comprehensive GC cell line database to identify the specifically expressed genes in gastric SRCC. We focused on MUC20 and investigated its role in GC progression. Survival analysis revealed that GC patients with high MUC20 expression exhibited a poor prognosis and that MUC20 expression was significantly correlated with SRCC histological type. Moreover, we found that gastric SRCC cells specifically expressed MUC20v2, which was dominantly expressed in the cytoplasm. Silencing MUC20v2 caused cell death with characteristic morphological changes in gastric SRCC cells. To further determine the types of cell death, we examined apoptosis, pyroptosis and ferroptosis by detecting cleaved PARP, gasdermin E-N-terminal (GSDME-N), and lipid reactive oxygen species (ROS) levels, respectively. We found that apoptosis and pyroptosis occurred in MUC20-silenced gastric SRCC cells. In addition, MUC20v2-overexpressing GC cells exhibited chemoresistance to cisplatin (CDDP) and paclitaxel (PTX). RNA sequencing revealed that the pathways involved in intracellular calcium regulation were significantly upregulated in MUC20v2-overexpressing GC cells. Notably, forced expression of MUC20v2 in the cytoplasm of GC cells led to the maintenance of mitochondrial calcium homeostasis and mitochondrial membrane potential (MMP), which promoted cell survival and chemoresistance by suppressing apoptosis and pyroptosis. Finally, we investigated the significance of MUC20v2 in a xenograft model treated with CDDP and showed that MUC20v2 overexpression caused chemoresistance by inhibiting cell death.

CONCLUSION

These findings highlight the novel functions of MUC20v2, which may confer cell survival and drug resistance in GC cells.

SIGNIFICANCE

MUC20v2 protects GC cells from apoptosis and pyroptosis by maintaining mitochondrial calcium levels and mitochondrial membrane potential and subsequently induces drug resistance.

Reduction of lactoferrin aggravates neuronal ferroptosis after intracerebral hemorrhagic stroke in hyperglycemic mice

Diabetic hyperglycemia aggravates the prognosis of intracerebral hemorrhagic stroke (ICH) in the clinic. In addition to hematoma expansion and increased inflammation, how diabetic hyperglycemia affects the outcomes of ICH is still unclear. We found that streptozotocin-induced diabetic hyperglycemia not only increased neutrophil infiltration, but also changed the gene expression profile of neutrophils, including lactoferrin (Ltf) encoding gene Ltf. Peroxisome proliferator-activated receptor γ (PPARγ) transcribed Ltf and the lack of neutrophilic Ltf transcription and secretion exacerbated neuronal ferroptosis by accumulating intraneuronal iron. Furthermore, the administration of recombinant Ltf protected against neuronal ferroptosis and improved neurobehavior in hyperglycemic ICH mice, and vice versa. These results indicate that supplementing Ltf or inhibiting neuronal ferroptosis are promising potential strategies to improve the acute outcomes of diabetic ICH in the clinic.

•

Neutrophil infiltration and ICH prognosis are aggravated in hyperglycemic mice.

•

Hyperglycemia impairs PPAR-γ activity and decreases Ltf expression in neutrophils.

•

The lack of neutrophilic Ltf fails to decrease intraneuronal iron and ferroptosis.

•

rLtf eases neuronal ferroptosis and neurologic deficits in hyperglycemic ICH mice.

Predictors of Symptomatic Hemorrhage After Endovascular Treatment for Anterior Circulation Occlusions: Turkish Endovascular Stroke Registry

We evaluated the predictive factors of symptomatic intracranial hemorrhage (SICH) in endovascular treatment of stroke. We included 975 ischemic stroke patients with anterior circulation occlusion. Patients that had hemorrhage and an increase of ≥4 points in their National Institutes of Health Stroke Scale (NIHSS) after the treatment were considered as SICH. The mean age of patients was 65.2±13.1 years and 469 (48.1%) were women. The median NIHSS was 16 (13-18) and Alberta Stroke Program Early CT 9 (8-10). In 420 patients (43.1%), modified Rankin Scale was favorable (0-2) and mortality was observed in 234 (24%) patients at the end of the third month. Patients with high diastolic blood pressure (P<.05) had significantly higher SICH. SICH was significantly higher in those with high NIHSS scores (P<.001), high blood glucose (P<.001), and leukocyte count at admission (P<.05). Diabetes mellitus (DM) (OR 1.90; P<.001), NIHSS (OR 1.07; P<.05), adjuvant intra-arterial thrombolytic therapy (IA-rtPA) (OR, 1.60; P<.05), and puncture-recanalization time (OR 1.01; P<.05) were independent factors of SICH. Higher baseline NIHSS score, longer procedure time, multiple thrombectomy maneuvers, administration of IA-rtPA, and the history of DM are independent predictors of SICH in anterior circulation occlusion.

Early-phase administration of human amnion-derived stem cells ameliorates neurobehavioral deficits of intracerebral hemorrhage by suppressing local inflammation and apoptosis

Background

Intracerebral hemorrhage (ICH) is a significant cause of death and disabilities. Recently, cell therapies using mesenchymal stem cells have been shown to improve ICH-induced neurobehavioral deficits. Based on these findings, we designed this study to evaluate the therapeutic efficacy and underlying mechanisms by which human amnion-derived stem cells (hAMSCs) would ameliorate neurobehavioral deficits of ICH-bearing hosts.

Methods

hAMSCs were induced from amnia obtained by cesarean section and administered intravenously to ICH-bearing mice during the acute phase. The mice were then subject to multitask neurobehavioral tests at the subacute phase. We attempted to optimize the dosage and timing of the hAMSC administrations. In parallel with the hAMSCs, a tenfold higher dose of human adipose-derived stem cells (ADSCs) were used as an experimental control. Specimens were obtained from the ICH lesions to conduct immunostaining, flow cytometry, and Western blotting to elucidate the underlying mechanisms of the hAMSC treatment.

Results

The intravenous administration of hAMSCs to the ICH-bearing mice effectively improved their neurobehavioral deficits, particularly when the treatment was initiated at Day 1 after the ICH induction. Of note, the hAMSCs promoted clinical efficacy equivalent to or better than that of hADSCs at 1/10 the cell number. The systemically administered hAMSCs were found in the ICH lesions along with the local accumulation of macrophages/microglia. In detail, the hAMSC treatment decreased the number of CD11b⁺CD45⁺ and Ly6G⁺ cells in the ICH lesions, while splenocytes were not affected. Moreover, the hAMSC treatment decreased the number of apoptotic cells in the ICH lesions. These results were associated with suppression of the protein expression levels of macrophage-related factors iNOS and TNFα.

Conclusions

Intravenous hAMSC administration during the acute phase would improve ICH-induced neurobehavioral disorders. The underlying mechanism was suggested to be the suppression of subacute inflammation and apoptosis by suppressing macrophage/microglia cell numbers and macrophage functions (such as TNFα and iNOS). From a clinical point of view, hAMSC-based treatment may be a novel strategy for the treatment of ICH.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12974-022-02411-3.

Hyperglycemia in acute ischemic stroke: physiopathological and therapeutic complexity

Diabetes mellitus and associated chronic hyperglycemia enhance the risk of acute ischemic stroke and lead to worsened clinical outcome and increased mortality. However, post-stroke hyperglycemia is also present in a number of non-diabetic patients after acute ischemic stroke, presumably as a stress response. The aim of this review is to summarize the main effects of hyperglycemia when associated to ischemic injury in acute stroke patients, highlighting the clinical and neurological outcomes in these conditions and after the administration of the currently approved pharmacological treatment, i.e. insulin. The disappointing results of the clinical trials on insulin (including the hypoglycemic events) demand a change of strategy based on more focused therapies. Starting from the comprehensive evaluation of the physiopathological alterations occurring in the ischemic brain during hyperglycemic conditions, the effects of various classes of glucose-lowering drugs are reviewed, such as glucose-like peptide-1 receptor agonists, DPP-4 inhibitors and sodium glucose cotransporter 2 inhibitors, in the perspective of overcoming the up-to-date limitations and of evaluating the effectiveness of new potential therapeutic strategies.

Association Between Raised HbA1c Levels and Hemorrhagic Transformation in Patients With Ischemic Stroke

Background

Glycated hemoglobin (HbA1c) is a commonly used indicator of glycemic control in diabetes mellitus. Uncontrolled diabetes can lead to cardiovascular complications. Ischemic strokes are often complicated by hemorrhagic transformation, which is the conversion of an infarcted area into an area of hemorrhage. The purpose of this study is to determine the association of raised HbA1c levels with the occurrence of hemorrhagic transformation in ischemic stroke.

Methods

This is a prospective, single-center cohort study of patients admitted to the Neurology and Medicine wards between June 1 and November 30, 2019. Inclusion criteria included adult patients who were admitted with acute ischemic stroke and had been tested for HbA1c on presentation. There were 110 ischemic stroke patients enrolled in our database. An HbA1c level >53 mmol/mol was considered raised. A comparison was done between the group with raised HbA1c levels and the group with target levels of HbA1c for the occurrence of hemorrhagic transformation. Brain imaging was used to diagnose hemorrhagic transformation.

Results

Out of 110 study participants with ischemic stroke, 70 (63.6%) patients had a history of prior known diabetes. The mean HbA1c levels were 7.44 ± 1.79%. A total of 77% of diabetic patients had raised HbA1c levels (>7%). Hemorrhagic transformation was seen in 21 (19.1%) patients, of whom only 38% (n=8) had raised HbA1c levels. The association between raised HbA1c and hemorrhagic transformation was not found to be statistically significant (p = 0.225).

Conclusion

In this study of patients with ischemic stroke, raised HbA1c levels were not found to be associated with hemorrhagic transformation. There is a need for larger scale studies to find out the cause and mechanism of hemorrhagic transformation in ischemic stroke.

Exacerbated VEGF up-regulation accompanies diabetes-aggravated hemorrhage in mice after experimental cerebral ischemia and delayed reperfusion

Reperfusion therapy is the preferred treatment for ischemic stroke, but is hindered by its short treatment window, especially in patients with diabetes whose reperfusion after prolonged ischemia is often accompanied by exacerbated hemorrhage. The mechanisms underlying exacerbated hemorrhage are not fully understood. This study aimed to identify this mechanism by inducing prolonged 2-hour transient intraluminal middle cerebral artery occlusion in diabetic Ins2^Akita/+ mice to mimic patients with diabetes undergoing delayed mechanical thrombectomy. The results showed that at as early as 2 hours after reperfusion, Ins2^Akita/+ mice exhibited rapid development of neurological deficits, increased infarct and hemorrhagic transformation, together with exacerbated down-regulation of tight-junction protein ZO-1 and up-regulation of blood-brain barrier-disrupting matrix metallopeptidase 2 and matrix metallopeptidase 9 when compared with normoglycemic Ins2^+/+ mice. This indicated that diabetes led to the rapid compromise of vessel integrity immediately after reperfusion, and consequently earlier death and further aggravation of hemorrhagic transformation 22 hours after reperfusion. This observation was associated with earlier and stronger up-regulation of pro-angiogenic vascular endothelial growth factor (VEGF) and its downstream phospho-Erk1/2 at 2 hours after reperfusion, which was suggestive of premature angiogenesis induced by early VEGF up-regulation, resulting in rapid vessel disintegration in diabetic stroke. Endoplasmic reticulum stress-related pro-apoptotic C/EBP homologous protein was overexpressed in challenged Ins2^Akita/+ mice, which suggests that the exacerbated VEGF up-regulation may be caused by overwhelming endoplasmic reticulum stress under diabetic conditions. In conclusion, the results mimicked complications in patients with diabetes undergoing delayed mechanical thrombectomy, and diabetes-induced accelerated VEGF up-regulation is likely to underlie exacerbated hemorrhagic transformation. Thus, suppression of the VEGF pathway could be a potential approach to allow reperfusion therapy in patients with diabetic stroke beyond the current treatment window. Experiments were approved by the Committee on the Use of Live Animals in Teaching and Research of the University of Hong Kong [CULATR 3834-15 (approval date January 5, 2016); 3977-16 (approval date April 13, 2016); and 4666-18 (approval date March 29, 2018)].

Inflammatory Biomarkers and Intracranial Hemorrhage after Endovascular Thrombectomy

BACKGROUND

Intracranial hemorrhage after endovascular thrombectomy is associated with poorer prognosis compared with those who do not develop the complication. Our study aims to determine predictors of post-EVT hemorrhage - more specifically, inflammatory biomarkers present in baseline serology.

METHODS

We performed a retrospective review of consecutive patients treated with EVT for acute large vessel ischemic stroke. The primary outcome of the study is the presence of ICH on the post-EVT scan. We used four definitions: the SITS-MOST criteria, the NINDS criteria, asymptomatic hemorrhage, and overall hemorrhage. We identified nonredundant predictors of outcome using backward elimination based on Akaike Information Criteria. We then assessed prediction accuracy using area under the receiver operating curve. Then we implemented variable importance ranking from logistic regression models using the drop in Naegelkerke R2 with the exclusion of each predictor.

RESULTS

Our study demonstrates a 6.3% SITS (16/252) and 10.0% NINDS (25/252) sICH rate, as well as a 19.4% asymptomatic (49/252) and 29.4% (74/252) overall hemorrhage rate. Serologic markers that demonstrated association with post-EVT hemorrhage were: low lymphocyte count (SITS), high neutrophil count (NINDS, overall hemorrhage), low platelet to lymphocyte ratio (NINDS), and low total WBC (NINDS, asymptomatic hemorrhage).

CONCLUSION

Higher neutrophil counts, low WBC counts, low lymphocyte counts, and low platelet to lymphoycyte ratio were baseline serology biomarkers that were associated with post-EVT hemorrhage. Our findings, particularly the association of diabetes mellitus and high neutrophil, support experimental data on the role of thromboinflammation in hemorrhagic transformation of large vessel occlusions.

Loss of MIC60 Aggravates Neuronal Death by Inducing Mitochondrial Dysfunction in a Rat Model of Intracerebral Hemorrhage

Mitochondrial damage has been reported to be a critical factor for secondary brain injury (SBI) induced by intracerebral hemorrhage (ICH). MIC60 is a key element of the mitochondrial contact site and cristae junction organizing system (MICOS), which takes a principal part in maintaining mitochondrial structure and function. The role of MIC60 and its underlying mechanisms in ICH-induced SBI are not clear, which will be investigated in this present study. To establish and emulate ICH model in vivo and in vitro, autologous blood was injected into the right basal ganglia of Sprague-Dawley (SD) rats; and primary-cultured cortical neurons were treated by oxygen hemoglobin (OxyHb). First, after ICH induction, mitochondria were damaged and exhibited mitochondrial crista-structure remodeling, and MIC60 protein levels were reduced. Furthermore, MIC60 overexpression reduced ICH-induced neuronal death both in vivo and in vitro. In addition, MIC60 upregulation reduced ICH-induced cerebral edema, neurobehavioral impairment, and cognitive dysfunction; by contrast, MIC60 knockdown had the opposite effect. Additionally, in primary-cultured neurons, MIC60 overexpression could reverse ICH-induced neuronal cell death and apoptosis, mitochondrial membrane potential collapse, and decrease of mitophagy, indicating that MIC60 overexpression can maintain the integrity of mitochondrial structures. Moreover, loss of MIC60 is after ICH-induced reduction in PINK1 levels and mislocalization of Parkin in primary-cultured neurons. Taken together, our findings suggest that MIC60 plays an important role in ICH-induced SBI and may represent a promising target for ICH therapy.

Melatonin protects against focal cerebral ischemia-reperfusion injury in diabetic mice by ameliorating mitochondrial impairments: involvement of the Akt-SIRT3-SOD2 signaling pathway

Diabetic patients are more vulnerable to cerebral ischemia-reperfusion (CIR) injury and have a worse prognosis and higher mortality after ischemic stroke than non-diabetic counterparts. Melatonin can exert neuroprotective effects against CIR injury in nondiabetic animal models. However, its effects on diabetic CIR injury and the underlying mechanisms remain unclarified. Herein, we found that melatonin administration improved neurological deficit, cerebral infarct volume, brain edema, and cell viability, reduced mitochondrial swelling, reactive oxygen species generation, and cytoplasmic cytochrome C release, and increased mitochondrial antioxidant enzymes activities, adenosine triphosphate production, and mitochondrial membrane potential in both streptozotocin-induced diabetic mice and high glucose-treated HT22 cells. Importantly, melatonin also activated protein kinase B (Akt) and sirtuin 3 (SIRT3)/superoxide dismutase 2 (SOD2) signaling and upregulated mitochondrial biogenesis-related transcription factors. However, these effects were largely attenuated by LY294002 (a specific Akt signaling blocker) administration. Additionally, 3-TYP (a selective SIRT3 inhibitor) and SIRT3 siRNA inhibited the above protective effects of melatonin as well as the upregulation of SIRT3 and the decrease of SOD2 acetylation but did not affect the p-Akt/Akt ratio. Overall, we demonstrate that melatonin can alleviate CIR injury in diabetic mice by activating Akt-SIRT3-SOD2 signaling and subsequently improving mitochondrial damage.

Xiao-Xu-Ming decoction prevented hemorrhagic transformation induced by acute hyperglycemia through inhibiting AGE-RAGE-mediated neuroinflammation

Stroke is one of the leading causes of death worldwide. Hemorrhagic transformation (HT) is a common serious complication of ischemic stroke (IS) and is related to poor prognosis. Hyperglycemia after stroke is associated with the occurrence of HT and seriously affects the clinical treatment of stroke. Our previous experiments demonstrated that the Xiao-Xu-Ming decoction effective components group (XXMD), which is a Chinese medicine formula reconstituted by active ingredients, has multiple pharmacological effects in the treatment of IS. However, the effects of XXMD on HT after IS remain unclear. Thus, we investigated the preventive effects of XXMD on hyperglycemia-induced HT and further explored the underlying mechanism. Acute hyperglycemia combined with the electrocoagulation cerebral ischemia model was used to establish the HT model. XXMD (37.5, 75, 150 mg/kg/d) was given by gavage for 5 days. Network pharmacology was used to predict potential targets and pathways of XXMD in HT occurrence, and further studies confirmed the related targets. The results showed that hyperglycemia aggravated neurological deficits and blood-brain barrier (BBB) disruption, leading to intracerebral hemorrhage. Pretreatment with XXMD improved neurological function and BBB integrity and inhibited HT occurrence. Network pharmacology revealed that AGE-RAGE-mediated neuroinflammation may be associated with hyperglycemia-induced HT. Further studies confirmed that hyperglycemia activated the AGE-RAGE signaling pathway, increased the expression of HMGB1, TLR4 and p-p65, and induced the release of inflammatory factors and neutrophil infiltration, leading to HT. XXMD could inhibit AGE-RAGE-mediated neuroinflammation. These findings indicated that pretreatment with XXMD alleviated hyperglycemia-induced HT, which may be associated with the inhibition of AGE-RAGE-mediated neuroinflammation. Therefore, XXMD may be a potential therapeutic drug for HT.

Melatonin Ameliorates Hemorrhagic Transformation via Suppression of ROS-Induced NLRP3 Activation after Cerebral Ischemia in Hyperglycemic Rats

Melatonin is a strong antioxidant which beneficially protects against middle cerebral artery occlusion (MCAO) followed by hemorrhagic transformation in rats; protection includes the reduction of neurological deficits, infarction, and hematoma volume. The molecular mechanisms underlying these neuroprotective effects in the MCAO model have not been clearly identified. This study examined the influence and involved mechanism of melatonin on inflammation in hemorrhagic transformation following hyperglycemia MCAO rat model. Compared with the MCAO group, MCAO+dextrose (DX) group showed worse neurological function and higher infarction and hematoma volume. Interestingly, the protein expression of Nod-like receptor protein 3 (NLRP3) inflammasome increased in the MCAO+DX group compared with the MCAO group, which indicated that NLRP3 inflammasome may be involved in the DX-induced hemorrhagic transformation following MCAO. Then, three dosages of melatonin were intraperitoneally injected 2 h after MCAO induction. Melatonin treatment attenuated inflammatory response by inhibiting the reactive oxygen species (ROS) and NLRP3 inflammasome, alleviating neuronal injury, and reducing infarction and hematoma volume, finally improving neurological score. Melatonin also repressed cortical levels of proinflammatory cytokine IL-1β, which were increased 24 h after hyperglycemia MCAO. In order to identify the potential mechanisms, we further revealed that nigericin administration reversed the neuroprotective effect of melatonin by promoting NLRP3 inflammasome activation. In general, this present study reveals that melatonin prevents the occurrence of hyperglycemia-enhanced hemorrhagic transformation, and this effect might be beneficial to attenuate neurological dysfunction via suppressing the inflammatory response after MCAO which possibly associated with the inhibition of the ROS/NLRP3 inflammasome pathway.

Histopathologic evaluation of saphenous vein grafts in patients with type II diabetes mellitus undergoing coronary artery bypass grafting

INTRODUCTION

Diabetes Mellitus (DM) has been known to be a risk factor for the development of more severe form of saphenous vein graft disease after coronary artery bypass grafting (CABG). We aimed to evaluate the impact of type II-DM on histopathological features of great saphenous vein grafts of patients undergoing CABG.

PATIENTS AND METHODS

Forty consecutive patients undergoing elective CABG were enrolled into the study. Patients were grouped into two; Diabetic group (n = 20); includes patients with preoperative diagnosis of type II-DM and Nondiabetic group (n = 20): those without type II-DM. In all patients, a short segment of the great saphenous vein graft at the level of medial malleolus was taken for light microscopy and transmission electron microscopy (TEM) evaluation. Moreover, immunoexpressions of Caveolin-1, Vascular cell adhesion protein 1 (VCAM-1) and endothelial nitric oxide synthase (eNOS) were studied.

RESULTS

There were no differences in the demographics of patients between two groups. The magnitude of intimal fibrosis in diabetic group was slightly higher than in nondiabetics (1.95 ± 0.99 versus 1.3 ± 0.8, P = .04). In TEM, vacuolization in endothelial cells, substance accumulation along with coarse collagen fibers and cytoplasmic degeneration with vacuolization in muscle cells were detected in diabetic group. While there were no differences in Caveolin-1 and VCAM-1 immunostaining, the intensity of positive eNOS immunostaining was significantly higher in endothelium (2.10 ± 0.64 versus 1.55 ± 0.68, P = .01) and tunica media 1.75 ± 0.63 versus 1.2 ± 0.52, P = .007) in nondiabetic group, respectively) compared with diabetic group.

CONCLUSION

Type II DM might be a reason for decreased expression of eNOS and increased intimal fibrosis, vacuolization of endothelial and smooth muscle cells in saphenous vein grafts. The clinical implications of these alterations on the graft patency need to be evaluated.

Intracerebral Hemorrhage and Diabetes Mellitus: Blood-Brain Barrier Disruption, Pathophysiology, and Cognitive Impairments

There is a surge in diabetes incidence with an estimated 463 million individuals been diagnosed worldwide. Diabetes Mellitus (DM) is a major stroke-related comorbid condition that increases the susceptibility of disabling post-stroke outcomes. Although less common, intracerebral hemorrhage (ICH) is the most dramatic subtype of stroke that is associated with higher mortality, particularly in DM population. Previous studies have focused mainly on the impact of DM on ischemic stroke. Few studies have focused on impact of DM on ICH and discussed the blood-brain barrier disruption, brain edema, and hematoma formation. However, more recently, investigating the role of oxidative damage and reactive oxygen species (ROS) production in preclinical studies involving DM-ICH animal models has gained attention. But, little is known about the correlation between neuroinflammatory processes, glial cells activation, and peripheral immune cell invasion with DM-ICH injury. DM and ICH patients experience impaired abilities in multiple cognitive domains by relatively comparable mechanisms, which could get exacerbated in the setting of comorbidities. In this review, we discuss both the pathology of DM as a comorbid condition for ICH and the potential molecular therapeutic targets for the clinical management of the ICH and its recovery.

Intracranial Bleeding After Reperfusion Therapy in Acute Ischemic Stroke

Intracranial hemorrhage is one of the most feared complications following brain infarct. Ischemic tissues have a natural tendency to bleed. Moreover, the first recanalization trials using intravenous thrombolysis have shown an increase in mild to severe intracranial hemorrhage. Symptomatic intracerebral hemorrhage is strongly associated with poor outcomes and is an important factor in recanalization decisions. Stroke physicians have to weigh the potential benefit of recanalization therapies, first, with different risks of intracranial hemorrhage described in randomized controlled trials, and second with numerous risk markers that have been found to be associated with intracranial hemorrhage in retrospective series. These decisions have become quite complex with different intravenous thrombolytics and mechanical thrombectomy. This review aims to outline some elements of the pathophysiological mechanisms and classifications, describe most of the risk factors identified for each reperfusion therapy, and finally suggest future research directions that could help physicians dealing with these complications.

Impact of aging and comorbidities on ischemic stroke outcomes in preclinical animal models: A translational perspective

Ischemic stroke is a highly complex and devastating neurological disease. The sudden loss of blood flow to a brain region due to an ischemic insult leads to severe damage to that area resulting in the formation of an infarcted tissue, also known as the ischemic core. This is surrounded by the peri-infarct region or penumbra that denotes the functionally impaired but potentially salvageable tissue. Thus, the penumbral tissue is the main target for the development of neuroprotective strategies to minimize the extent of ischemic brain damage by timely therapeutic intervention. Given the limitations of reperfusion therapies with recombinant tissue plasminogen activator or mechanical thrombectomy, there is high enthusiasm to combine reperfusion therapy with neuroprotective strategies to further reduce the progression of ischemic brain injury. Till date, a large number of candidate neuroprotective drugs have been identified as potential therapies based on highly promising results from studies in rodent ischemic stroke models. However, none of these interventions have shown therapeutic benefits in stroke patients in clinical trials. In this review article, we discussed the urgent need to utilize preclinical models of ischemic stroke that more accurately mimic the clinical conditions in stroke patients by incorporating aged animals and animal stroke models with comorbidities. We also outlined the recent findings that highlight the significant differences in stroke outcome between young and aged animals, and how major comorbid conditions such as hypertension, diabetes, obesity and hyperlipidemia dramatically increase the vulnerability of the brain to ischemic damage that eventually results in worse functional outcomes. It is evident from these earlier studies that including animal models of aging and comorbidities during the early stages of drug development could facilitate the identification of neuroprotective strategies with high likelihood of success in stroke clinical trials.

CNS and peripheral immunity in cerebral ischemia: partition and interaction

Stroke elicits excessive immune activation in the injured brain tissue. This well-recognized neural inflammation in the brain is not just an intrinsic organ response but also a result of additional intricate interactions between infiltrating peripheral immune cells and the resident immune cells in the affected areas. Given that there is a finite number of immune cells in the organism at the time of stroke, the partitioned immune systems of the central nervous system (CNS) and periphery must appropriately distribute the limited pool of immune cells between the two domains, mounting a necessary post-stroke inflammatory response by supplying a sufficient number of immune cells into the brain while maintaining peripheral immunity. Stroke pathophysiology has mainly been neurocentric in focus, but understanding the distinct roles of the CNS and peripheral immunity in their concerted action against ischemic insults is crucial. This review will discuss stroke-induced influences of the peripheral immune system on CNS injury/repair and of neural inflammation on peripheral immunity, and how comorbidity influences each.

Predictors of intracranial hemorrhage in acute ischemic stroke after endovascular thrombectomy

BACKGROUND

Limited data are available regarding the predictors, clinical relevance, and bleeding rate by surgical devices of intracranial hemorrhage after endovascular thrombectomy. This is partially explained by the difference in the classification and definition of hemorrhage among studies. The purpose of this study was to identify the predictors of hemorrhagic transformation and isolated subarachnoid hemorrhage after endovascular thrombectomy.

METHODS

This was a retrospective, multicenter observational cohort study of consecutive patients who underwent endovascular thrombectomy between January 2015 and December 2018. Univariate and logistic regression analyses were performed to determine the predictors, the impact on clinical outcomes, and the bleeding rate by surgical devices of hemorrhagic transformation and isolated subarachnoid hemorrhage.

RESULTS

Among 610 eligible patients, hemorrhagic transformations occurred in 93 (15.2%). Fourteen patients (2.3%) were classified as having symptomatic intracranial hemorrhage. Isolated subarachnoid hemorrhage was found in 60 (9.8%) patients. In the logistic regression analyses, diabetes mellitus (odds ratio: 1.92; 95% confidence interval: 1.06-3.49) was associated with hemorrhagic transformation, and the number of device passes (odds ratio: 1.33; 95% confidence interval: 1.11-1.59) was associated with isolated subarachnoid hemorrhage. Both hemorrhagic transformation and isolated subarachnoid hemorrhage were associated with poor 90-day functional outcomes. There was a significant correlation between treatment with stent retrievers and isolated subarachnoid hemorrhage.

CONCLUSIONS

Patients with diabetes mellitus were vulnerable to hemorrhagic transformation, whereas those who underwent several attempts of thrombectomy were susceptible to isolated subarachnoid hemorrhage. Both hemorrhage types worsened the functional outcome. Treatment with the stent retriever was significantly associated with postprocedural isolated subarachnoid hemorrhage.

Immune-Inflammatory, Metabolic, Oxidative, and Nitrosative Stress Biomarkers Predict Acute Ischemic Stroke and Short-Term Outcome

Immune-inflammatory, metabolic, oxidative, and nitrosative stress (IMO&NS) pathways and, consequently, neurotoxicity are involved in acute ischemic stroke (IS). The simultaneous assessment of multiple IMO&NS biomarkers may be useful to predict IS and its prognosis. The aim of this study was to identify the IMO&NS biomarkers, which predict short-term IS outcome. The study included 176 IS patients and 176 healthy controls. Modified Rankin scale (mRS) was applied within 8 h after IS (baseline) and 3 months later (endpoint). Blood samples were obtained within 24 h after hospital admission. IS was associated with increased white blood cell (WBC) counts, high sensitivity C-reactive protein (hsCRP), interleukin (IL-6), lipid hydroperoxides (LOOHs), nitric oxide metabolites (NOx), homocysteine, ferritin, erythrocyte sedimentation rate (ESR), glucose, insulin, and lowered iron, 25-hydroxyvitamin D [25(OH)D], total cholesterol, and high-density lipoprotein (HDL) cholesterol. We found that 89.4% of the IS patients may be correctly classified using the cumulative effects of male sex, systolic blood pressure (SBP), glucose, NOx, LOOH, 25(OH)D, IL-6, and WBC with sensitivity of 86.2% and specificity of 93.0%. Moreover, increased baseline disability (mRS ≥ 3) was associated with increased ferritin, IL-6, hsCRP, WBC, ESR, and glucose. We found that 25.0% of the variance in the 3-month endpoint (mRS) was explained by the regression on glucose, ESR, age (all positively), and HDL-cholesterol, and 25(OH)D (both negatively). These results show that the cumulative effects of IMO&NS biomarkers are associated with IS and predict a poor outcome at 3-month follow-up.

Targets, Treatments, and Outcomes Updates in Diabetic Stroke

GOAL

Due to multiple failures to translate basic research, the need for novel therapeutic targets and strategies is still urgent to save a larger number of the stroke patients' population and to reduce the toxicity of the current stroke therapy.

METHOD

We summarize the most recent, within past 5 years, basic and clinical diabetic stroke research findings.

FINDINGS

We aim to examine the most current understanding of stroke and neurovascular unit integrity, especially in presence of hyperglycemia and/or diabetes mellitus. From there, we are comparing the meaningful findings that aim at treating diabetic stroke to see where they differ, where they succeed, and where they open questions for new therapeutic strategies.

CONCLUSION

The need for more clinically effective neuroprotective strategies is still mismatched with the bench side findings.

Influences of blood lipids on the occurrence and prognosis of hemorrhagic transformation after acute cerebral infarction: a case-control study of 732 patients

BACKGROUND

To study the influence of blood lipid levels on hemorrhagic transformation (HT) and prognosis after acute cerebral infarction (ACI).

METHODS

Patients with ACI within 72 h of symptoms onset between January 1st, 2015, and December 31st, 2016, were retrospectively analyzed. Patients were divided into group A (without HT) and group B (HT). The outcomes were assessed after 3 months of disease onset using the modified Rankin Scale (mRS). An mRS score of 0-2 points indicated excellent prognosis, and an mRS score of 3-6 points indicated poor prognosis.

RESULTS

A total of 732 patients conformed to the inclusion criteria, including 628 in group A and 104 in group B. The incidence of HT was 14.2%, and the median onset time was 2 d (interquartile range, 1-7 d). The percentages of patients with large infarct size and cortex involvement in group B were 80.8 and 79.8%, respectively, which were both significantly higher than those in group A (28.7 and 33.4%, respectively). The incidence rate of atrial fibrillation (AF) in group B was significantly higher than that in group A (39.4% vs. 13.9%, P < 0.001). The adjusted multivariate analysis results showed that large infarct size, cortex involvement and AF were independent risk factors of HT, while total cholesterol (TC) was a protective factor of HT (OR = 0.359, 95% CI 0.136-0.944, P = 0.038). With every 1 mmol/L reduction in normal TC levels, the risk of HT increased by 64.1%. The mortality and morbidity at 3 months in group B (21.2 and 76.7%, respectively) were both significantly higher than those in group A (8.0 and 42.8%, respectively). The adjusted multivariate analysis results showed that large infarct size (OR = 12.178, 95% CI 5.390-27.516, P < 0.001) was an independent risk factor of long-term unfavorable outcomes, whereas low-density lipoprotein cholesterol (LDL-C) was a protective factor (OR = 0.538, 95% CI 0.300-0.964, P = 0.037). With every 1 mmol/L reduction in normal LDL-C levels, the risk of an unfavorable outcome increased by 46.2%. Major therapies, including intravenous recombinant human tissue plasminogen activator (rTPA), intensive lipid-lowering statins and anti-platelets, were not significantly related to either HT or long-term, post-ACI poor prognosis.

CONCLUSION

For patients with large infarct sizes, especially those with cortex involvement, AF, or lower levels of TC, the risk of HT might increase after ACI. The risk of a long-term unfavorable outcome in these patients might increase with a reduction in LDL-C.

Therapeutic Options Targeting Oxidative Stress, Mitochondrial Dysfunction and Inflammation to Hinder the Progression of Vascular Complications of Diabetes

Type 2 diabetes mellitus is a leading cause of morbidity and mortality worldwide, given its serious associated complications. Despite constant efforts and intensive research, an effective, ubiquitous treatment still eludes the scientific community. As such, the identification of novel avenues of research is key to the potential discovery of this evasive "silver bullet." We focus on this review on the matter of diabetic injury to endothelial tissue and some of the pivotal underlying mechanisms, including hyperglycemia and hyperlipidemia evoked oxidative stress and inflammation. In this sense, we revisited the most promising therapeutic interventions (both non-pharmacological and antidiabetic drugs) targeting oxidative stress and inflammation to hinder progression of vascular complications of diabetes. This review article gives particular attention to the relevance of mitochondrial function, an often ignored and understudied organelle in the vascular endothelium. We highlight the importance of mitochondrial function and number homeostasis in diabetic conditions and discuss the work conducted to address the aforementioned issue by the use of various therapeutic strategies. We explore here the functional, biochemical and bioenergetic alterations provoked by hyperglycemia in the endothelium, from elevated oxidative stress to inflammation and cell death, as well as loss of tissue function. Furthermore, we synthetize the literature regarding the current and promising approaches into dealing with these alterations. We discuss how known agents and therapeutic behaviors (as, for example, metformin, dietary restriction or antioxidants) can restore normality to mitochondrial and endothelial function, preserving the tissue's function and averting the aforementioned complications.

Correlation of hyperglycemia with mortality after acute ischemic stroke

Background:

Hyperglycemia has been considered a predictor of stroke outcomes. In this article we study the correlation between blood glucose levels within the first 24 h after stroke onset and patients’ outcomes in mortality and hemorrhagic transformations.

Methods:

Ninety-one non-diabetic patients with acute ischemic stroke admitted to a neurological intensive unit were recruited. Their blood glucose was measured twice within 6 h (baseline) and at every hour after stroke onset. Patients were collected into four groups as follows: those in which normoglycemia and no hyperglycemia were observed at either baseline or 24 h; those with baseline hyperglycemia and hyperglycemia only at baseline; those with 24 h hyperglycemia and hyperglycemia only at 24 h after stroke; and those with persistent hyperglycemia and hyperglycemia at both baseline and at 24 h. Endpoints were designated as the patient’s death within 30 days and/or hemorrhagic transformation under computerized tomography within the first 7 days after stroke onset.

Results:

Persistent hyperglycemia was correlated with an increased risk of mortality within 30 days (OR = 24.0; 95% CI = 2.8–199.3) and it was also correlated with hemorrhagic transformation (OR = 13.3; 95% CI = 2.7–66.1). Baseline or delayed hyperglycemia were not correlated with any outcome.

Conclusions:

Persistent hyperglycemia was correlated with mortality after acute ischemic stroke.

Potential biomarkers for predicting hemorrhagic transformation of ischemic stroke

Reperfusion therapy contributes to better clinical outcomes in patients with acute ischemic stroke but carries a more significant risk of hemorrhagic transformation (HT) compared to supportive care. Once HT occurs, the outcome is usually poor and this causes a dilemma in the treatment of ischemic stroke. Consequently, early prediction of HT would be extremely helpful for guiding precise treatment of ischemic stroke. In this review, we focus on summarizing biomarkers of HT and elucidating possible mechanisms so as to identify potential biomarkers for predicting HT.

miR-Let7A Controls the Cell Death and Tight Junction Density of Brain Endothelial Cells under High Glucose Condition

Hyperglycemia-induced stress in the brain of patients with diabetes triggers the disruption of blood-brain barrier (BBB), leading to diverse neurological diseases including stroke and dementia. Recently, the role of microRNA becomes an interest in the research for deciphering the mechanism of brain endothelial cell damage under hyperglycemia. Therefore, we investigated whether mircoRNA Let7A (miR-Let7A) controls the damage of brain endothelial (bEnd.3) cells against high glucose condition. Cell viability, cell death marker expressions (p-53, Bax, and cleaved poly ADP-ribose polymerase), the loss of tight junction proteins (ZO-1 and claudin-5), proinflammatory response (interleukin-6, tumor necrosis factor-α), inducible nitric oxide synthase, and nitrite production were confirmed using MTT, reverse transcription-PCR, quantitative-PCR, Western blotting, immunofluorescence, and Griess reagent assay. miR-Let7A overexpression significantly prevented cell death and loss of tight junction proteins and attenuated proinflammatory response and nitrite production in the bEnd.3 cells under high glucose condition. Taken together, we suggest that miR-Let7A may attenuate brain endothelial cell damage by controlling cell death signaling, loss of tight junction proteins, and proinflammatory response against high glucose stress. In the future, the manipulation of miR-Let7A may be a novel solution in controlling BBB disruption which leads to the central nervous system diseases.

Inhibition of DPP-4 Activity and Neuronal Atrophy with Genistein Attenuates Neurological Deficits Induced by Transient Global Cerebral Ischemia and Reperfusion in Streptozotocin-Induced Diabetic Mice

Genistein, an isoflavonoid phytoestrogen, has been known for its potential pharmacological properties especially for neuroprotection and treating diabetes. The present study aims to determine the neuroprotective efficacy of genistein against global cerebral ischemia-reperfusion-induced neuronal injury in streptozotocin-induced diabetic mice and explore the underlying mechanisms. Streptozotocin-induced diabetic mice were subjected to transient cerebral ischemia by occluding both common carotid arteries for 30 min followed by 24 h reperfusion to induce neuronal injury. Effect of genistein (2.5, 5.0, and 10.0 mg/kg, i.p., o.d.) treatment on ischemia-reperfusion-induced neuronal injury in diabetic mice was evaluated in terms of cerebral infarct size, oxidative damage, mitochondrial activity in terms of neuronal apoptosis and cellular viability, dipeptidyl peptidase-4 activity and active glucagon-like peptide-1 concentration, and neurological functions measured as short-term memory and motor performance. Genistein administration following transient cerebral ischemia significantly (p ˂ 0.0001) counteracted cognitive impairment and re-established (p ˂ 0.001) motor performance in diabetic mice. Ischemia-reperfusion increased the infarct size, genistein administration prevented the increase in cerebral infarct size (p ˂ 0.0001) and significantly suppressed (p ˂ 0.001) the increase in cerebral oxidative stress in transient cerebral ischemia-reperfusion subjected diabetic mice. Genistein treatment significantly (p ˂ 0.001) reduced neuronal apoptosis and increased cellular viability (p ˂ 0.0001), almost completely suppressed (p ˂ 0.0001) the circulating dipeptidyl peptidase-4 activity, and enhanced (p ˂ 0.0001) glucagon-like peptide-1 concentration in diabetic mice with cerebral ischemia-reperfusion. This study suggests that genistein has potent neuroprotective activity against global cerebral ischemia-reperfusion-induced neuronal injury and consequent neurological deficits in streptozotocin-induced diabetic mice.

Mitochondria in endothelial cells: Sensors and integrators of environmental cues

The involvement of angiogenesis in disease and its potential as a therapeutic target have been firmly established over recent decades. Endothelial cells (ECs) are central elements in vessel homeostasis and regulate the passage of material and cells into and out of the bloodstream. EC proliferation and migration are modified by alterations to mitochondrial biogenesis and dynamics resulting from several signals and environmental cues, such as oxygen, hemodynamics, and nutrients. As intermediary signals, mitochondrial ROS are released as important downstream modulators of the expression of angiogenesis-related genes. In this review, we discuss the physiological actions of these signals and aberrant responses during vascular disorders.

•

Mitochondria in EC act as integrators of environmental cues.

•

Circulating signals modify mitochondrial dynamics, altering EC phenotype.

•

ROS release by EC mitochondria regulates expression of vascular genes.

Cilostazol ameliorates collagenase-induced cerebral hemorrhage by protecting the blood-brain barrier

Intracranial hemorrhage remains a devastating disease. Among antiplatelet drugs, cilostazol, a phosphodiesterase 3 inhibitor, was recently reported to prevent secondary hemorrhagic stroke in patients in a clinical trial. The aim of this study was to evaluate whether pre-treatment with cilostazol could decrease the intracranial hemorrhage volume and examine the protective mechanisms of cilostazol. We evaluated the pre-treatment effects of the antiplatelet drug cilostazol on the collagenase-induced intracranial hemorrhage volume and neurological outcomes in mice. To estimate the mechanism of collagenase injury, we evaluated various vascular components in vitro, including endothelial cells, vascular smooth muscle cells, pericytes, and a blood-brain barrier model. Cilostazol pre-treatment reduced the intracranial hemorrhage volume with sufficient inhibition of platelet aggregation, and motor function was improved by cilostazol treatment. Blood-brain barrier permeability was increased by collagenase-induced intracranial hemorrhage, and cilostazol attenuated blood-brain barrier leakage. Terminal deoxynucleotidyl transferase dUTP nick-end labeling and western blot analysis showed that cilostazol prevented pericyte cell death by inducing cyclic adenosine monophosphate-responsive element-binding protein phosphorylation. Cilostazol also prevented endothelial cell death and protected collagen type 4, laminin, and vascular endothelial- and N-cadherins from collagenase injury. In conclusion, cilostazol reduced collagenase-induced intracranial hemorrhage volume by protecting the blood-brain barrier.

Vessel Dilation Attenuates Endothelial Dysfunction Following Middle Cerebral Artery Occlusion in Hyperglycemic Rats

OBJECTIVES

Dynamically observe cerebral vascular changes in hyperglycemic rats in vivo and explore the effect of diabetes on endothelial function after ischemic stroke.

BACKGROUND

Diabetes affects both large and small vessels in the brain, but the dynamic process and mechanism are unclear.

METHODS

We investigated the structural and functional changes of brain vasculature in living hyperglycemic rats and their impact on stroke outcomes via a novel technique: synchrotron radiation angiography. We also examined the effect of prolonged fasudil treatment on arterial reactivity and hemorrhagic transformation. Adult Sprague Dawley rats were treated by streptozotocin to induce type 1 diabetes. These hyperglycemic rats received fasudil pretreatment and then underwent transient middle cerebral artery occlusion.

RESULTS

We found that diabetes caused arteries narrowing in the circus Willis as early as 2 weeks after streptozotocin injection (P < 0.05). These vessels were further constricted after middle cerebral artery occlusion. L-NAME could induce regional constrictions and impaired relaxation in hyperglycemic animals. Furthermore, hemorrhagic transformation was also increased in the hyperglycemic rats compared to the control (P < 0.05). In fasudil-treated rats, the internal carotid artery narrowing was ameliorated and L-NAME-induced regional constriction was abolished. Importantly, stroke prognosis was improved in fasudil-treated rats compared to the control (P < 0.05).

CONCLUSIONS

Our dynamic angiographic data demonstrated that diabetes could impair the cerebral arterial reactivity. Prolonged fasudil treatment could attenuate arterial dysfunction and improve the prognosis of ischemic stroke by affecting both the large and small vasculature.

Mitochondrial Regulation of the Muscle Microenvironment in Critical Limb Ischemia

Critical limb ischemia (CLI) is the most severe clinical presentation of peripheral arterial disease and manifests as chronic limb pain at rest and/or tissue necrosis. Current clinical interventions are largely ineffective and therapeutic angiogenesis based trials have shown little efficacy, highlighting the dire need for new ideas and novel therapeutic approaches. Despite a decade of research related to skeletal muscle as a determinant of morbidity and mortality outcomes in CLI, very little progress has been made toward an effective therapy aimed directly at the muscle myopathies of this disease. Within the muscle cell, mitochondria are well positioned to modulate the ischemic cellular response, as they are the principal sites of cellular energy production and the major regulators of cellular redox charge and cell death. In this mini review, we update the crucial importance of skeletal muscle to CLI pathology and examine the evolving influence of muscle and endothelial cell mitochondria in the complex ischemic microenvironment. Finally, we discuss the novelty of muscle mitochondria as a therapeutic target for ischemic pathology in the context of the complex co-morbidities often associated with CLI.