Repeated Oral Administration of Human Serum Albumin Protects from the Cerebral Ischemia in Rat Brain Following MCAO

Neuroprotective Effect of Melatonin Loaded in Human Serum Albumin Nanoparticles Applied Subconjunctivally in a Retinal Degeneration Animal Model

BACKGROUND/OBJECTIVES

Neurodegenerative ocular diseases, such as age-related macular degeneration (AMD) and glaucoma, represent growing public health concerns. Oxidative stress plays a key role in their development, damaging retinal cells and accelerating disease progression. Melatonin (Mel) is a potent antioxidant with neuroprotective properties; however, it faces limitations such as low solubility. This study proposes the use of human serum albumin nanoparticles (Np-HSA) to enhance the delivery of Mel to the posterior segment of the eye and evaluates its neuroprotective and anti-apoptotic effects on the retina.

METHODS

A model of retinal degeneration was induced in New Zealand albino rabbits using cytotoxic and oxidative agents. Np-HSA-Mel nanoparticles were administered subconjunctivally, and cellular viability and retinal functionality were assessed using flow cytometry and pupillary light reflex (PLR). Histological and immunohistochemical studies, including the TUNEL assay, were performed to analyse cell survival and apoptotic index.

RESULTS

Np-HSA-Mel significantly preserved pupillary function and cell viability, demonstrating lower apoptosis compared to Mel solution and Np-HSA alone. Histologically, eyes treated with Np-HSA-Mel exhibited fewer structural alterations and greater cellular organisation. The TUNEL assay confirmed a significant reduction in the apoptotic index of retinal ganglion cells (RGCs) treated with Np-HSA-Mel.

CONCLUSIONS

Np-HSA-Mel effectively overcame ocular barriers, achieving greater neuroprotective efficacy at the retinal level. These findings highlight the synergistic potential of albumin and Mel in treating neurodegenerative ocular diseases, opening new perspectives for future therapies.

Association between fibrinogen-to-albumin ratio and functional prognosis of 3 months in patients with acute ischemic stroke after intravenous thrombolysis

BACKGROUND

The presence of high fibrinogen and low albumin levels in serum is associated with a negative prognosis in acute ischemic stroke (AIS). Fibrinogen-to-albumin ratio (FAR), a new inflammatory biomarker, may provide better prognostic insights in patients with AIS than separate evaluation of fibrinogen or albumin. The objective of this investigation is to examine the correlation between FAR and 3-month functional prognosis after intravenous thrombolysis (IVT) in AIS patients.

METHODS

The retrospective study recruited AIS patients who received IVT from June 2014 to December 2021. The 3-month functional prognosis was assessed using the Modified Rankin Scale (mRS). A mRS score of ≤2 indicated a good outcome, whereas a mRS score of >2 suggested a poor outcome.

RESULTS

A total of 591 AIS patients who underwent IVT were included and 147 patients (24.9 %) had a poor outcome. Among the 102 pairs of patients after propensity score matching, there was a significant association between FAR and 3-month prognosis (adjusted OR, 1.19; 95% CI, 1.03-1.38; p = .020). The optimal FAR cutoff value was found to be 7.57, and even after stratifying patients based on this value, we still observed a significant correlation between high FAR level and poor outcome (adjusted OR, 2.08; 95% CI, 1.28-3.40; p = .003).

CONCLUSIONS

FAR may serve as a prospective biomarker of predicting 3-month prognosis in AIS patients after IVT.

Inhibition of lipid synthesis by the HIV integrase strand transfer inhibitor elvitegravir in primary rat oligodendrocyte cultures

Combined antiretroviral therapy (cART) has greatly decreased mortality and morbidity among persons with HIV; however, neurologic impairments remain prevalent, in particular HIV-associated neurocognitive disorders (HANDs). White matter damage persists in cART-treated persons with HIV and may contribute to neurocognitive dysfunction as the lipid-rich myelin membrane of oligodendrocytes is essential for efficient nerve conduction. Because of the importance of lipids to proper myelination, we examined the regulation of lipid synthesis in oligodendrocyte cultures exposed to the integrase strand transfer inhibitor elvitegravir (EVG), which is administered to persons with HIV as part of their initial regimen. We show that protein levels of genes involved in the fatty acid pathway were reduced, which correlated with greatly diminished de novo levels of fatty acid synthesis. In addition, major regulators of cellular lipid metabolism, the sterol regulatory element-binding proteins (SREBP) 1 and 2, were strikingly altered following exposure to EVG. Impaired oligodendrocyte differentiation manifested as a marked reduction in mature oligodendrocytes. Interestingly, most of these deleterious effects could be prevented by adding serum albumin, a clinically approved neuroprotectant. These new findings, together with our previous study, strengthen the possibility that antiretroviral therapy, at least partially through lipid dysregulation, may contribute to the persistence of white matter changes observed in persons with HIV and that some antiretrovirals may be preferable as life-long therapy.

Association between fibrinogen-to-albumin ratio and hemorrhagic transformation after intravenous thrombolysis in ischemic stroke patients

BACKGROUND AND PURPOSE

Hemorrhagic transformation (HT) is the most serious complication of intravenous thrombolysis in ischemic stroke patients. Inflammation plays a critical role in the pathological progression of HT. This study was to explore the relationship between fibrinogen-to-albumin ratio (FAR), a novel systemic inflammation biomarker, and HT after intravenous thrombolysis in patients with ischemic stroke.

METHODS

This retrospective study enrolled ischemic stroke patients who underwent intravenous thrombolysis between Jan 2017 to May 2022. The characteristic data of all patients at admission were retrospectively collected. The univariate and multivariate logistic regression analyses were performed to evaluate the correlation between FAR and HT after intravenous thrombolysis. The optimal cut-off value of FAR for predicting HT was determined by the receiver operating characteristic curve.

RESULTS

A total of 363 ischemic stroke patients were enrolled in the present study. Sixty-two patients had HT after intravenous thrombolysis. In multivariate regression analysis, FAR was significantly associated with HT (odds ratio [OR], 1.105; 95% confidential interval [CI], 1.029-1.186, P = 0.006). The receiver operating characteristic curve analysis indicated FAR predicts HT after intravenous thrombolysis with an AUC of 0.613 (95%CI, 0.530-0.695; P = 0.005) and an optimal cut-off value of 0.101. The correlation between FAR and HT after intravenous thrombolysis was still observed when patients were stratified according to FAR levels. A higher FAR level was independently related to the occurrence of HT after adjusting for the potential confounding factors.

CONCLUSION

Higher FAR level was independently associated with HT after intravenous thrombolysis in patients with ischemic stroke.

Human serum albumin in neurodegeneration

Serum albumin (SA) exists in relatively high concentrations, in close contact with most cells. However, in the adult brain, except for cerebrospinal fluid (CSF), SA concentration is relatively low. It is mainly produced in the liver to serve as the main protein of the blood plasma. In the plasma, it functions as a carrier, chaperon, antioxidant, source of amino acids, osmoregulator, etc. As a carrier, it facilitates the stable presence and transport of the hydrophobic and hydrophilic molecules, including free fatty acids, steroid hormones, medicines, and metal ions. As a chaperon, SA binds to and protects other proteins. As an antioxidant, thanks to a free sulfhydryl group (-SH), albumin is responsible for most antioxidant properties of plasma. These functions qualify SA as a major player in, and a mirror of, overall health status, aging, and neurodegeneration. The low concentration of SA is associated with cognitive deterioration in the elderly and negative prognosis in multiple sclerosis (MS) and amyotrophic lateral sclerosis (ALS). SA has been shown to be structurally modified in neurological conditions such as Alzheimer's disease (AD). During blood-brain barrier damage albumin enters the brain tissue and could trigger epilepsy and neurodegeneration. SA is able to bind to the precursor agent of the AD, amyloid-beta (Aβ), preventing its toxic effects in the periphery, and is being tested for treating this disease. SA therapy may also be effective in brain rejuvenation. In the current review, we will bring forward the prominent properties and roles of SA in neurodegeneration.

High fibrinogen-to-albumin ratio is associated with hemorrhagic transformation in acute ischemic stroke patients

INTRODUCTION

Hemorrhagic transformation (HT) is a complex and multifactorial complication among patients with acute ischemic stroke (AIS), and the inflammatory response has been considered as a risk factor for HT. We aimed to evaluate the stratification of FAR (fibrinogen-to-albumin ratio), an inflammatory biomarker, in HT patients.

METHODS

A total of 256 consecutive stroke patients with HT and 256 age- and gender-matched stroke patients without HT were included in this study. HT during hospitalization was diagnosed by follow-up imaging assessment and was classified into hemorrhagic infarction (HI) and parenchymal hematoma (PH) according to the recommendations of European Cooperative Acute Stroke Study II classification. Blood samples were obtained at admission.

RESULTS

Higher levels of FAR were observed in patients with HT compared with the non-HT group [10.29 (8.39-12.95) vs. 8.60 (7.25-10.8), p < .001], but no significant difference was found between the PH and HI [10.88 (8.72-13.40) vs. 10.13 (8.14-12.60), p > .05]. Patients were assigned to groups of high FAR (≥9.51) and low FAR (<9.51) based on the optimal cut-off value. After adjustment for potential confounders, the high FAR remained independently associated with the increased risk of HT (OR = 5.027, 95% CI = 5.027 (2.309-10.942), p < .001).

CONCLUSIONS

High FAR was independently associated with the increased risk of HT after AIS.

Hypertensive Response to Ischemic Stroke in the Normotensive Wistar Rat

Background and Purpose—

Over 80% of ischemic stroke patients show an abrupt increase in arterial blood pressure in the hours and days following ischemic stroke. Whether this poststroke hypertension is beneficial or harmful remains controversial and the underlying physiological basis is unclear.

Methods—

To investigate the dynamic cardiovascular response to stroke, adult Wistar rats (n=5–8 per group, 393±34 g) were instrumented with telemeters to blood pressure, intracranial pressure, renal sympathetic nerve activity, and brain tissue oxygen in the predicted penumbra (P o 2 ). After 2 weeks of recovery, cardiovascular signals were recorded for a 3-day baseline period, then ischemic stroke was induced via transient middle cerebral artery occlusion, or sham surgery. Cardiovascular signals were then recorded for a further 10 days, and the functional sensorimotor recovery assessed using the cylinder and sticky dot tests.

Results—

Baseline values of all variables were similar between groups. Compared to sham, in the 2 days following stroke middle cerebral artery occlusion produced an immediate, transient rise above baseline in mean blood pressure (21±3 versus 2±4 mm Hg; P <0.001), renal sympathetic nerve activity (54±11% versus 7±4%; P =0.006), and cerebral perfusion pressure (12±5 versus 1±4; P ≤0.001). Intracranial pressure increased more slowly, peaking 3 days after middle cerebral artery occlusion (14±6 versus −1±1 mm Hg; P <0.001). Treating with the antihypertensive agent nifedipine after stroke (1.5–0.75 mg/kg per hour SC) ameliorated poststroke hypertension (12±3 mm Hg on day 1; P =0.041), abolished the intracranial pressure increase (3±1; P <0.001) and reduced cerebral perfusion pressure (10±3 mm Hg; P =0.017). Preventing poststroke hypertension affected neither the recovery of sensorimotor function nor infarct size.

Conclusions—

These findings suggest that poststroke hypertension is immediate, temporally matched to an increase in sympathetic outflow, and elevates cerebral perfusion pressure for several days after stroke, which may enhance cerebral perfusion. Preventing poststroke hypertension does not appear to worsen prognosis after stroke in young, normotensive, and otherwise healthy rats.

Visual Overview—

An online visual overview is available for this article.

A new era for stroke therapy: Integrating neurovascular protection with optimal reperfusion

Recent advances in stroke reperfusion therapies have led to remarkable improvement in clinical outcomes, but many patients remain severely disabled, due in part to the lack of effective neuroprotective strategies. In this review, we show that 95% of published preclinical studies on "neuroprotectants" (1990-2018) reported positive outcomes in animal models of ischemic stroke, while none translated to successful Phase III trials. There are many complex reasons for this failure in translational research, including that the majority of clinical trials did not test early delivery of neuroprotectants in combination with successful reperfusion. In contrast to the clinical trials, >80% of recent preclinical studies examined the neuroprotectant in animal models of transient ischemia with complete reperfusion. Furthermore, only a small fraction of preclinical studies included long-term functional assessments, aged animals of both genders, and models with stroke comorbidities. Recent clinical trials demonstrate that 70%-80% of patients treated with endovascular thrombectomy achieve successful reperfusion. These successes revive the opportunity to retest previously failed approaches, including cocktail drugs that target multiple injury phases and different cell types. It is our hope that neurovascular protectants can be retested in future stroke research studies with specific criteria outlined in this review to increase translational successes.

The protective mechanism underlying total flavones of Dracocephalum (TFD) effects on rat cerebral ischemia reperfusion injury

Previously, total flavones of Dracocephalum (TFD), derived from Dracocephalum, were found to exert protective effects in cerebral ischemia reperfusion injury (CIRI) in middle cerebral artery occlusion (MCAO) rat model. However, the mechanisms underlying these observed effects of TFD on MCAO-induced rats still remain to be determined. Therefore, the aim of this study was to examine whether TFD alleviated MCAO through mechanisms involving anti-inflammatory and anti-apoptotic using MCAO rats. The following parameters were measured: (1) percentage (%) area of brain infarction; (2) serum levels of inflammatory cytokines, including tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6) and (3) expression protein levels of caspase-3 and AMP-activated protein kinase (AMPK). Results showed that MCAO significantly increased the % area of brain infarction, while TFD administration in these animals markedly reduced % area of brain infarction. A significant elevation on serum levels of TNF-α and IL-6 was noted with MCAO which was markedly reduced by TFD. In addition, MCAO produced a significant rise in protein expression levels of caspase-3 and AMPK. In contrast, TFD markedly lowered protein expression levels of caspase-3 and AMPK. Data suggest that the protective effects of TFD in MCAO model animals may involve inhibition of inflammatory mediator release associated with apoptosis through down regulation of AMPK signaling pathway.

The protective mechanism underlying total flavones of Dracocephalum (TFD) effects on rat cerebral ischemia reperfusion injury

Previously, total flavones of Dracocephalum (TFD), derived from Dracocephalum, were found to exert protective effects in cerebral ischemia reperfusion injury (CIRI) in middle cerebral artery occlusion (MCAO) rat model. However, the mechanisms underlying these observed effects of TFD on MCAO-induced rats still remain to be determined. Therefore, the aim of this study was to examine whether TFD alleviated MCAO through mechanisms involving anti-inflammatory and anti-apoptotic using MCAO rats. The following parameters were measured: (1) percentage (%) area of brain infarction; (2) serum levels of inflammatory cytokines, including tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6) and (3) expression protein levels of caspase-3 and AMP-activated protein kinase (AMPK). Results showed that MCAO significantly increased the % area of brain infarction, while TFD administration in these animals markedly reduced % area of brain infarction. A significant elevation on serum levels of TNF-α and IL-6 was noted with MCAO which was markedly reduced by TFD. In addition, MCAO produced a significant rise in protein expression levels of caspase-3 and AMPK. In contrast, TFD markedly lowered protein expression levels of caspase-3 and AMPK. Data suggest that the protective effects of TFD in MCAO model animals may involve inhibition of inflammatory mediator release associated with apoptosis through down regulation of AMPK signaling pathway.

The role of histone deacetylase inhibitors in regulation of Akt/GSK-3β signaling pathway in mice following transient focal cerebral ischemia

PURPOSE

To investigate whether the neuroprotective effect of TSA on cerebral ischemia reperfusion injury is mediated by the activation of Akt/GSK-3β signaling pathway.

METHODS

Mice were randomly divided into four groups (n=15): sham group (S); ischemia reperfusion group (IR); ischemia reperfusion and pretreated with TSA group (IR+T); ischemia reperfusion and pretreated with TSA and LY294002 group (IR+T+L). The model of cerebral ischemia reperfusion was established by 1h of MCAO following 24h of reperfusion. TSA (5mg/kg) was intraperitoneally given for 3 days before MCAO, Akt inhibitor, LY294002 (15 nmol/kg) was injected by tail vein 30 min before the MCAO.

RESULTS

TSA significantly increased the expression of p-Akt, p-GSK-3β proteins and the levels of SOD, Bcl-2, reduced the infarct volume and the levels of MDA, ROS, TNF-α, IL-1β, Bax, Caspase-3, TUNEL and attenuated neurological deficit in mice with transient MCAO, LY294002 weakened such effect of TSA dramatically.

CONCLUSIONS

TSA could significantly decrease the neurological deficit and reduce the cerebral infarct volume, oxidative stress, inflammation, as well as apoptosis during cerebral ischemia reperfusion injury, which was achieved by activation of the Akt/GSK-3β signaling pathway.

The inhibitory effects of Dracocephalum moldavica L. (DML) on rat cerebral ischemia reperfusion injury

Ischemia reperfusion injury (IRI) is closely associated with oxidative stress and inflammatory responses. Dracocephalum moldavica L. (DML), a Chinese herbal medicine is known to exert protective effects on myocardial ischemia reperfusion injury in rats by inhibiting oxidation damage and inflammatory reactions. However, the effectiveness of DML in cerebral ischemia reperfusion injury (CIRI) as a protective substance and the underlying mechanisms remain to be determined. The aim of this study was thus to examine the influence of DML on CIRI using a rat model induced by 2-h transient middle cerebral artery occlusion (MCAO) produced by intraluminal suture blockade followed by 22 h reperfusion. The parameters determined include neurological behavior, histochemical assessment of cerebral infarct volume, and determination of various metabolic biomarkers. Data showed that DML markedly improved neurobehavioral scores and reduced cerebral edema and infarction. In addition, DML significantly reduced malondialdehyde (MDA) content and elevated activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), in addition, marked decrease in levels of interleukin-6 (IL-6), interleukin-8 (IL-8), and tumor necrosis factor-α (TNF-α). Data suggest that the protective effects of DML on CIRI may be related to processes involving antioxidation and anti-inflammation.