Blood-brain barrier dysfunction in hemorrhagic transformation: a therapeutic opportunity for nanoparticles and melatonin

Correlation between impaired brachial flow-mediated dilation and hemorrhagic transformation after acute reperfusion therapy

OBJECTIVE

Hemorrhagic transformation (HT) represents a critical complication of reperfusion therapy, often resulting in unfavorable functional outcomes. Our objective was to explore the correlation between endothelial function, assessed through flow-mediated dilation (FMD), and the occurrence of HT in patients undergoing acute reperfusion therapy.

MATERIALS AND METHODS

In our retrospective analysis, we investigated patients with emergent large vessel occlusion (ELVO) who underwent acute reperfusion therapy and assessment through FMD, calculated as %FMD = (peak diameter - baseline diameter)/baseline diameter×100. HT was categorized according to the European Cooperative Acute Stroke Study (ECASS) definition. Through multivariate analysis, we explored factors associated with HT, considering stroke mechanisms, and delved into the relationship between FMD and HT.

RESULTS

A total of 172 patients were included in this study, with 45.3% experiencing HT. Factors associated with HT included high initial National Institute of Health Stroke Scale (NIHSS) scores [7 (5-10) vs. 10 (8-14); P <0.001], receiving tissue plasminogen activator (tPA) (21.3 vs. 39.7%; P<0.001), undergoing endovascular therapy (EVT) 10.6 vs. 26.9%; P <0.001), and impaired %FMD (6.2±2.5 vs. 4.9±1.8; P = 0.022). In a subgroup analysis of patients with cardioembolism, receiving EVT was significantly associated with HT (reference: tPA only; adjusted odds ratio [aOR] = 7.000; 95% confidence interval, 1.173-41.759; P = 0.033). In those with large artery atherosclerosis (LAA), a higher initial NIHSS score (aOR = 1.274; 1.082-1.499; P = 0.004) and impaired %FMD (aOR = 0.632; 0.402-0.995; P = 0.047) were independently associated with HT.

CONCLUSIONS

Endothelial dysfunction, indicated by impaired %FMD, emerges as a potential predictor of HT following acute reperfusion therapy, particularly in patients with LAA.

Risk factors and prediction models for recurrent acute ischemic stroke: a retrospective analysis

Background

Ischemic stroke is one of the leading causes of disability and death worldwide, with a high risk of recurrence that severely impacts the quality of life of patients. Therefore, identifying and analyzing the risk factors for recurrent ischemic stroke is crucial for the prevention and management of this disease.

Methods

A total of 114 cases of recurrent acute ischemic stroke patients admitted from July 2017 to March 2021 were selected as the observation group, and another 409 cases of initial ischemic stroke patients from the same period as the control group. The clinical data of the observation group and the control group were compared to analyze the risk factors associated with the readmission of ischemic stroke. A single-factor analysis (Model 1), Least Absolute Shrinkage and Selection Operator (LASSO) regression, and machine learning methods (Model 2) were used to screen important variables, and a multi-factor COX Proportional Hazards Model regression stroke recurrence risk prediction model was constructed. The predictive performance of the model was evaluated by the consistency index (C-index).

Results

Multivariate COX regression analysis revealed that history of hypertension (Hazard Ratio [HR] = 2.549; 95% Confidence Interval (CI) [1.503-4.321]; P = 0.001), history of cerebral infarction (HR = 1.709; 95% CI [1.066-2.738]; P = 0.026), cerebral artery stenosis (HR = 0.534; 95% CI [0.306-0.931]; P = 0.027), carotid arteriosclerosis (HR = 1.823; 95% CI [1.137-2.924]; P = 0.013), systolic blood pressure (HR = 0.981; 95% CI [0.971-0.991]; P < 0.0001), red cell distribution width-coefficient of variation (RDW-CV) (HR = 1.251; 95% CI [1.019-1.536]; P = 0.033), mean platelet volume (MPV) (HR = 1.506; 95% CI [1.148-1.976]; P = 0.003), uric acid (UA) (HR = 0.995; 95% CI [0.991-1.000]; P = 0.049) were found significantly associated with acute ischemic stroke. The C-index of the full COX model was 0.777 (0.732~0.821), showing a good discrimination between Model 1 and Model 2.

Conclusions

History of hypertension, history of cerebral infarction, cerebral artery stenosis, carotid atherosclerosis, systolic blood pressure, UA, RDW-CV, and MPV were identified as risk factors for acute ischemic stroke recurrence. The model can be used to predict the recurrence of acute ischemic stroke.

Investigating the therapeutic effects of nimodipine on vasogenic cerebral edema and blood-brain barrier impairment in an ischemic stroke rat model

Vasogenic brain edema, a potentially life-threatening consequence following an acute ischemic stroke, is a major clinical problem. This research aims to explore the therapeutic benefits of nimodipine, a calcium channel blocker, in mitigating vasogenic cerebral edema and preserving blood-brain barrier (BBB) function in an ischemic stroke rat model. In this research, animals underwent the induction of ischemic stroke via a 60-min blockage of the middle cerebral artery and treated with a nonhypotensive dose of nimodipine (1 mg/kg/day) for a duration of five days. The wet/dry method was employed to identify cerebral edema, and the Evans blue dye extravasation technique was used to assess the permeability of the BBB. Furthermore, immunofluorescence staining was utilized to assess the protein expression levels of matrix metalloproteinase-9 (MMP-9) and intercellular adhesion molecule-1 (ICAM-1). The study also examined mitochondrial function by evaluating mitochondrial swelling, succinate dehydrogenase (SDH) activity, the collapse of mitochondrial membrane potential (MMP), and the generation of reactive oxygen species (ROS). Post-stroke administration of nimodipine led to a significant decrease in cerebral edema and maintained the integrity of the BBB. The protective effects observed were associated with a reduction in cell apoptosis as well as decreased expression of MMP-9 and ICAM-1. Furthermore, nimodipine was observed to reduce mitochondrial swelling and ROS levels while simultaneously restoring MMP and SDH activity. These results suggest that nimodipine may reduce cerebral edema and BBB breakdown caused by ischemia/reperfusion. This effect is potentially mediated through the reduction of MMP-9 and ICAM-1 levels and the enhancement of mitochondrial function.

Acute calcitriol treatment mitigates vitamin D deficiency-associated mortality after intracerebral haemorrhage

OBJECTIVE

Vitamin D deficiency (VDD) is emerging as a predictor of poor prognosis in various neurological conditions, where clinical outcomes are often worse in stroke patients with VDD. This study aimed to provide experimental evidence on whether and how pre-existing VDD would affect survival and neurofunctional outcomes in intracerebral haemorrhage (ICH), and to evaluate whether acute vitamin D (VD) supplementation would improve post-stroke outcomes.

METHODS

Experimental ICH models were induced in mice with and without VDD. Haematoma size was measured using T2*-weighted MRI and haemoglobin concentration. Post-ICH mortality, neurofunctional outcomes and the extent of blood-brain barrier (BBB) leakage were assessed to identify their correlations with VD status. Therapeutic benefits of acute VD administration were also evaluated.

RESULTS

Mice with VDD exhibited significantly higher acute mortality rates and more severe motor deficits than mice without VDD post-ICH. Marked haematoma expansion and increased Evans blue extravasation were observed in VDD mice, suggesting that VDD was associated outcomes with increased BBB disruption. Acute treatment with a loading dose of VD (calcitriol) significantly improved outcomes in VDD mice.

CONCLUSION

This study provides novel insights into the pathophysiological mechanisms at play in ICH concomitant with VDD and a scientific rationale for acute treatment with VD.

Melatonin and metformin co-loaded nanoliposomes efficiently attenuate liver damage induced by bile duct ligation in rats

In the current study, the therapeutic effectiveness of the metformin (Met) and melatonin (Mel) co-loaded liposomes was investigated on cholestasis induced by bile duct ligation (BDL) in male rats. Histopathological analysis, biochemical analysis, and oxidative stress markers were assayed to determine the therapeutic effect of Met and Mel co-loaded liposomes on cholestasis. Histopathological analysis revealed that the simultaneous administration of Met and Mel, whether in the free (C-Mel-Met) or liposomal (C-Lipo-Mel-Met) forms, reduced inflammation as well as proliferation of bile ducts; however, results were more prominent in the liposomal form of Mel and Met. Additionaly, serum levels of aspartate aminotransferase (AST) were significantly (p < 0.001) higher in (C-Mel-Met) treated rats compared with (BDL) rats; however, (C-Lipo-Mel-Met) treated rats exhibited significant (p < 0.05) lower AST rates in comparison to (BDL) rats. Moreover, a significant (p < 0.0001) drop in bilirubin levels was detected in (C-Lipo-Mel-Met) treated rats in comparison to (BDL) rats; it is noteworthy mentioning that bilirubin levels in (C-Lipo-Mel-Met) treated rats were insignificant in comparison to sham-control (SC) rats. Furthermore, rats concomitantly administered Met and Mel, exhibited significant downregulation in the expression levels of inflammatory cytokine genes such as TNF-α and IL-1 gene expression, where the downregulation was more prominent in the liposomal from. Our findings demonestrate that the concomitant administration of metformin and melatonin in the liposomal form had more therapeutic effect on liver injury than their free forms through improving histological changes, reducing biochemical markers and favoring oxidant- antioxidant balance.

The therapeutic benefits of intravenously administrated nanoparticles in stroke and age-related neurodegenerative diseases

The mean global lifetime risk of neurological disorders such as stroke, Alzheimer's disease (AD), and Parkinson's disease (PD) has shown a large effect on economy and society.Researchersare stillstruggling to find effective drugs to treatneurological disordersand drug delivery through the blood-brain barrier (BBB) is a major challenge to be overcome. The BBB is a specialized multicellular barrier between the peripheral blood circulation and the neural tissue. Unique and selective features of the BBB allow it to tightly control brain homeostasis as well as the movement of ions and molecules. Failure in maintaining any of these substances causes BBB breakdown and subsequently enhances neuroinflammation and neurodegeneration.BBB disruption is evident in many neurologicalconditions.Nevertheless, the majority of currently available therapies have tremendous problems for drug delivery into the impaired brain. Nanoparticle (NP)-mediated drug delivery has been considered as a profound substitute to solve this problem. NPs are colloidal systems with a size range of 1-1000 nm whichcan encapsulate therapeutic payloads, improve drug passage across the BBB, and target specific brain areas in neurodegenerative/ischemic diseases. A wide variety of NPs has been displayed for the efficient brain delivery of therapeutics via intravenous administration, especially when their surfaces are coated with targeting moieties. Here, we discuss recent advances in the development of NP-based therapeutics for the treatment of stroke, PD, and AD as well as the factors affecting their efficacy after systemic administration.

Intra-Epidural Space Injection of OX26-PEGylated Selenium Nanoparticles Enhances Motor Function and Decrease the Risk of Neural Damage in Animal Model of Subarachnoid Hemorrhage

Objective: To evaluate the effectiveness of PEGylated (PEG) OX26 loaded with Selenium (Se) on locomotor activity and brain function and exploring underlying mechanism in animal model of subarachnoid hemorrhage (SAH). Methods: Thoracis spinal cord injury in Wistar rats was used to induce SAH and intra-epidural injection of OX26-PEG-Se nanoparticles (NPs) was then applied. Locomotor function test was used to evaluate the behavioral outcome in addition, ELISA kit was used to evaluate the serum level of NSE and S100B. Immunofluorescent imaging was used to detect the expression of eNOS and NT-1. In addition, NeuN staing was used to assess the neural damage. Results: The locomotor function of animals with SAH was significantly increase afgter treating with OX26-PEG-Se NPs. In addition, the expression levels of NSE and S100B were significantly decrease after treating animals with OX26-PEG-Se NPs in comparison to sham operated animals. We observed that OX26-PEG-Se NPs decrease the neural damage and the level of NT-1, while increase the eNOS in brain. Conclusion: Intra-epidural injection of OX26-PEG-Se NPs improved the locomotor activity and also inhibit the risk of neural damage through ET-1/eNOS pathway after subarachnoid hemorrhage.