Diffusion-weighted magnetic resonance imaging confirms marked neuroprotective efficacy of albumin therapy in focal cerebral ischemia

Association Between Postoperative Decrease of Albumin and Outcomes in Patients Undergoing Craniotomy for Brain Tumors

BACKGROUND

Serum albumin reflects nutritional status and is associated with postoperative complications and mortality. Delta albumin (ΔAlb), defined as the difference between preoperative and lowest postoperative levels, could predict complications and mortality, even with postoperative levels above 30 g/L prompting albumin infusions. This study aimed to assess how ΔAlb relates to outcomes in craniotomy patients with brain tumors.

METHODS

This retrospective study screened patients diagnosed with a brain tumor who underwent cerebral surgery from a single Chinese hospital between December 2010 and April 2021. Patients were divided into 4 groups based on their ΔAlb levels: <5 g/L (normal), 5-9.9 g/L (mild ΔAlb), 10-14.9 g/L (moderate ΔAlb), and ≥15 g/L (severe ΔAlb). The primary outcome was postoperative 30-day mortality.

RESULTS

Among the 9660 patients undergoing craniotomy for brain tumors, the median ΔAlb level after craniotomy was 7.3 g/L. ΔAlb was associated with increased postoperative 30-day mortality; odds ratios for mild, moderate, and severe ΔAlb were 1.93 (95% confidence interval [CI], 1.17-3.18, P = 0.01), 2.21 (95% CI, 1.28-3.79, P = 0.004), and 7.26 (95% CI, 4.19-12.58, P < 0.01), respectively. Significantly, ΔAlb >5 g/L was found to have a strong association with a higher risk of mortality, even when the nadir Alb remained greater than 30 g/L (odds ratio, 1.84; 95% CI, 1.13-3.00, P = 0.014).

CONCLUSIONS

Among patients undergoing craniotomy for brain tumor resection, a mild degree of ΔAlb was associated with increased 30-day mortality, even if the nadir Alb remained greater than 30 g/L. Moreover, ΔAlb was associated with postoperative complications and longer lengths of stay.

Albumin adjuvant therapy for acute ischemic stroke with large vessel occlusion (AMASS-LVO): rationale, design, and protocol for a phase 1, open-label, clinical trial

BACKGROUND

Acute ischemic stroke (AIS) is an acute brain injury caused by sudden occlusion of a blood vessel. Endovascular therapy is the most effective way to restore blood flow. However, despite the restoration of blood flow in some patients, their clinical prognosis often remains unsatisfactory. Albumin has shown neuroprotective effects in animal models of AIS. Therefore, this study aims to evaluate the safety, feasibility, and efficacy of local arterial infusions of 20% human serum albumin solution as an adjuvant therapy after endovascular therapy in patients with AIS.

METHODS

This study is a prospective, therapeutic exploratory, non-randomized, open-label, phase 1 clinical trial testing the use of 20% human serum albumin solution injected via the artery immediately after successful reperfusion in patients with AIS. The study is divided into two stages. In the first stage, a single-dose-finding will explore the maximum safe dose according to the 3 + 3 dose escalation principle;, with the maximum dose being 0.60 g/kg. After recanalizing the occluded blood vessel, human serum albumin solution will be injected into the internal carotid artery region through a guiding catheter for 30 min. The second stage involves an albumin adjuvant therapy cohort (AT) and an endovascular treatment lonely cohort (ET). The AT cohort will encompass at least 15 additional participants to complete safety trials at the maximum safe dose determined in the first stage. The ET cohort will include well-matched patients receiving endovascular therapy alone, derived from a contemporaneous prospective registry, who will be excluded from having cardiopulmonary disorders and from receiving any neuroprotective therapy. The primary outcome of this study will be symptomatic intracranial hemorrhage. Efficacy outcomes will include the proportion of patients with the progression of cerebral infarction volume, a modified Rankin Scale of 0-2 on day 90 after randomization. An exploratory secondary outcome will be the analysis of thromboinflammatory and neuroprotective molecule profiles.

CONCLUSION

This pilot trial aims to explore the safety and efficacy of arterial infusion of an albumin solution after occlusive vessel opening in AIS. The results will provide data parameters for subsequent tests on the arterial infusion of albumin solutions.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, NCT05953623.

In silico identification of molecular mechanisms for stroke risk caused by heavy metals and their mixtures: sponges and drugs involved

This study used various approaches and databases to evaluate the molecular processes and identify miRNA sponges and drugs associated with the development of stroke caused by heavy metals and their combinations. We found that the genes ALB (albumin), IL1B (Interleukin-1β), F2 (coagulation factor II), APOA1 (apolipoprotein A1), IL6 (Interleukin 6), and NOS2 (nitric oxide synthase 2) were linked to the development of strokes by 18 chemicals and a combination of cadmium, copper, and lead. These results may point to the significance of detoxification and neuroinflammation in stroke as well as the potential for targeting these genes in future stroke therapies. ALB and IL1B were the most common and significant genes. The "selenium micronutrient network," "vitamin B12 metabolism," and "folate metabolism" were shown to be the most significant pathways connected to the risk of stroke brought on by combined heavy metals. The two main cellular elements that may increase the risk of stroke caused by heavy metals were discovered to be "blood microparticle" and "endoplasmic reticulum lumen." We also observed an important chromosome (chr7p15.3), two transcription factors (NFKB2 [nuclear factor kappa B subunit 2] and NR1I2 [nuclear receptor subfamily 1 group, member 2]), and four microRNAs (hsa-miR-26a-5p, hsa-miR-9-5p, hsa-miR-124-3p, and hsa-miR-155-5p) associated with stroke caused by combined heavy metals. Additionally, for these miRNAs, we created and examined in silico microRNA sponge sequences. Triflusal and andrographolide have been identified as potential treatments for heavy metal-induced stroke. Taken together, heavy metals may be a significant contributor to the pathophysiology of stroke, but further investigation into the precise molecular pathways implicated in stroke pathophysiology is required to corroborate these findings.

A triple fusion tissue-type plasminogen activator (TriF-ΔtPA) enhanced thrombolysis in carotid embolism-induced stroke model

Recombinant tissue-type plasminogen activator (rtPA) is the first approved thrombolytic agent in acute ischemic stroke, but suffers from a short half-life and poor resistance to plasminogen activator inhibitor (PAI-1), limiting its clinical use. Thus, the development of novel thrombolytic agents with improved benefit/risk balance has always been of great significance. In this study, We identified a serine protease domain of tPA mutant (named ΔtPA^A146V) capable of escaping the inhibition by endogenous PAI-1 with 66-fold increased resistance compared to the wild type. Based on this mutant, we generated a triple fusion ΔtPA (TriF-ΔtPA), including albumin and fibrin binding peptide(FBP). The fusion with albumin effectively prolonged the plasma half-life of ΔtPA in mice to 144 minutes, which is much longer than ΔtPA and did not affect its thrombolytic activity. Furthermore, FBP rendered fibrin specificity of the fusion protein, giving a KD of ∼25 ± 0.9 μM. In a novel murine carotid embolism-induced stroke (CES) model, i.v. administration of TriF-ΔtPA promoted vascular recanalization, reduced infarct volume, and mitigated neurobehavioral deficits more significantly compared to ΔtPA-HSA or Alteplase, showing little bleeding risk. Together, this long-acting PAI-1-resistant thrombolytic agent holds great potential for clinical applications.

Nano-integrated cascade antioxidases opsonized by albumin bypass the blood-brain barrier for treatment of ischemia-reperfusion injury

Potent antioxidative drugs are urgently needed to treat ischemia-reperfusion (I/R) induced reactive oxygen species (ROS)-mediated cerebrovascular and neural injury during ischemia strokes. However, current antioxidative agents have limited application in such disease due to low blood-brain barrier (BBB) penetration. We herein designed a "neutrophil piggybacking" strategy based on albumin opsonized nanoparticles co-encapsulated with antioxidases catalase (CAT) and superoxide dismutase 1 (SOD1). The system utilized the natural potential of neutrophils to target inflamed tissues to deliver antioxidases to injured sites in the brain. In addition, the system was integrated with a selenium (Se)-containing crosslinker to inhibit ferroptosis. We showed that the nanoparticles opsonized in the hybrid form rather than with an albumin-shell structure exhibited enhanced neutrophil targeting and efficient BBB penetration in vitro and in vivo. We further showed that the neutrophil-mediated delivery of antioxidases effectively reduced oxidative damage and apoptosis of neurons in brain tissue in a transient middle cerebral artery occlusion (tMCAO) mouse model. Moreover, the successful delivery of Se with the nanoparticles increased the expression of glutathione peroxidase 4 (GPX4) and effectively inhibited neuronal ferroptosis, achieving a satisfactory neuroprotective effect in I/R injury mice. Our study demonstrated that the rationally designed nanomedicines using the "neutrophil piggybacking" strategy can efficiently penetrate the BBB, greatly expanding the application of nanomedicines in the treatment of central nervous system (CNS) diseases.

Circulating metabolites associated with incident myocardial infarction and stroke: A prospective cohort study of 90 438 participants

The relevance between circulating metabolites and vascular events remains controversial and comprehensive studies are lacking. We sought to investigate the prospective associations of plasma metabolomics with risks of incident stroke, ischemic stroke (IS), hemorrhagic stroke (HS), and myocardial infarction (MI). Within the UK Biobank cohort, 249 circulating metabolites were measured in 90 438 participants without baseline vascular diseases. Cox proportional hazards regressions were applied to estimate adjusted hazard ratios (HRs) for per 1 standard deviation increment in metabolites. The least absolute shrinkage and selection operator algorithm was used for selecting metabolite subsets. During a median of 9.0 years of follow-up, we documented 833 incident stroke and 1256 MI cases. Lipid constituents, comprising cholesterol, cholesteryl esters, free cholesterol, phospholipids, and total lipids, in very low- (VLDL), intermediate- (IDL), and low-density lipoprotein (LDL) particles were positively associated with MI risk (HR = 1.12 to 1.36; 95% CI = 1.06 to 1.44), while in high-density lipoprotein (HDL) particles showed inverse associations (HR = 0.68 to 0.81; 95% CI = 0.63 to 0.87). Similar association pattern with MI was also observed for VLDL, IDL, LDL, and HDL particles themselves. In contrast, triglycerides within all lipoproteins, including most HDL particles, were positively associated with MI risk (HR = 1.14 to 1.28; 95% CI = 1.08 to 1.35) and, to a slightly lesser extent, with stroke and IS. Unsaturation of fatty acids and albumin were inversely associated with risks of stroke, IS, and MI. In contrast, the linear association for HS is absent. When combining multiple metabolites, the metabolite risk score captured a drastically elevated risk of all vascular events, about twice that of any single metabolite. Taken together, circulating metabolites showed remarkably widespread associations with incident MI, but substantially weakened associations with risks of stroke and its subtypes. Exhaustive metabolomics profiling may shed light on vascular risk prediction and, in turn, guide pertinent strategies of intervention and treatment.

Optimizing acute stroke outcome prediction models: Comparison of generalized regression neural networks and logistic regressions

Background

Generalized regression neural network (GRNN) and logistic regression (LR) are extensively used in the medical field; however, the better model for predicting stroke outcome has not been established. The primary goal of this study was to compare the accuracies of GRNN and LR models to identify the most optimal model for the prediction of acute stroke outcome, as well as explore useful biomarkers for predicting the prognosis of acute stroke patients.

Method

In a single-center study, 216 (80% for the training set and 20% for the test set) acute stroke patients admitted to the Shenzhen Second People’s Hospital between December 2019 to June 2021 were retrospectively recruited. The functional outcomes of the patients were measured using Barthel Index (BI) on discharge. A training set was used to optimize the GRNN and LR models. The test set was utilized to validate and compare the performances of GRNN and LR in predicting acute stroke outcome based on the area under the receiver operating characteristic curve (AUROC), accuracy, sensitivity, and the Kappa value.

Result

The LR analysis showed that age, the National Institute Health Stroke Scale score, BI index, hemoglobin, and albumin were independently associated with stroke outcome. After validating in test set using these variables, we found that the GRNN model showed a better performance based on AUROC (0.931 vs 0.702), sensitivity (0.933 vs 0.700), specificity (0.889 vs 0.722), accuracy (0.896 vs 0.729), and the Kappa value (0.775 vs 0.416) than the LR model.

Conclusion

Overall, the GRNN model demonstrated superior performance to the LR model in predicting the prognosis of acute stroke patients. In addition to its advantage in not affected by implicit interactions and complex relationship in the data. Thus, we suggested that GRNN could be served as the optimal statistical model for acute stroke outcome prediction. Simultaneously, prospective validation based on more variables of the GRNN model for the prediction is required in future studies.

Explanation of machine learning models using shapley additive explanation and application for real data in hospital

BACKGROUND AND OBJECTIVE

When using machine learning techniques in decision-making processes, the interpretability of the models is important. In the present paper, we adopted the Shapley additive explanation (SHAP), which is based on fair profit allocation among many stakeholders depending on their contribution, for interpreting a gradient-boosting decision tree model using hospital data.

METHODS

For better interpretability, we propose two novel techniques as follows: (1) a new metric of feature importance using SHAP and (2) a technique termed feature packing, which packs multiple similar features into one grouped feature to allow an easier understanding of the model without reconstruction of the model. We then compared the explanation results between the SHAP framework and existing methods using cerebral infarction data from our hospital.

RESULTS

The interpretation by SHAP was mostly consistent with that by the existing methods. We showed how the A/G ratio works as an important prognostic factor for cerebral infarction using proposed techniques.

CONCLUSION

Our techniques are useful for interpreting machine learning models and can uncover the underlying relationships between features and outcome.

Albumin therapy for acute ischemic stroke: a meta-analysis

Human serum albumin has shown remarkable efficacy in rodent models of ischemic stroke, while results from relevant clinical research on albumin therapy remain controversial. We conducted a meta-analysis of published studies to quantitatively analyze the neurofunctional outcomes of patients with ischemic stroke treated with albumin. PubMed, Embase, and Cochrane Library were searched in July 2020. A total of four studies and 1611 patients were included. The aggregated results indicated that there were 635 patients with good neurological outcomes, among which 321 patients were in the albumin group (39.8%) and 314 patients in the control group (39.1%), showing no statistically significant difference between the albumin and control groups (OR = 1.04, 95% CI 0.85-1.27). The results suggest that albumin therapy at the acute stage of ischemic stroke has no beneficial effect on the long-term neurological function of patients with ischemic stroke. Considering pulmonary edema and other complications are more likely to occur in such patients after albumin infusion, the administration of albumin therapy for acute ischemic stroke should be done with utmost caution.

Frequency of Hypoalbuminemia and In-Hospital Mortality in Acute Ischemic Stroke Patients Presenting at a Tertiary Care Hospital, Hyderabad

Background The aim of this study was to determine the frequency of hypoalbuminemia and in-hospital mortality in acute ischemic stroke patients at a tertiary care hospital in Hyderabad. Methodology This was a prospective observational study conducted at the Department of Medicine, Isra University Hospital, Hyderabad, from February 17, 2017 to August 18, 2017. A total of 196 consecutive cases of acute ischemic stroke were included. Hypoalbuminemia was defined as serum albumin of <3.5 mg/dL. In-hospital outcome in terms of survival or death within seven days of admission was assessed and recorded. Data were analyzed using SPSS, version 20.0. (IBM Corp., Armonk, NY, US). Chi-square test was applied, and p-value of ≤0.05 was considered significant. Results Out of the 196 acute ischemic stroke cases, 146 (74.5%) were males and 50 (25.5%) were females. The mean age was 49.31 ± 10.46 years. A total of 90 (45.9%) cases had hypoalbuminemia. Out of these 196 cases, 22 (11.2%) expired within seven days of presentation of acute ischemic stroke, and out of these 22 expired cases, 18 (81.8%) had hypoalbuminemia. In-hospital mortality was found to be strongly associated with hypoalbuminemia (p < 0.001). Conclusions Frequency of hypoalbuminemia was significantly higher in ischemic stroke patients and was found to be associated with in-hospital mortality, warranting monitoring at regular intervals, as well as recognizing and treating it early for risk stratification.

Investigation of brain damage mechanism in middle cerebral artery occlusion/reperfusion rats based on i-TRAQ quantitative proteomics

The objective of this study is to analyze the differential protein expression profile in cerebral cortex of rats with middle cerebral ischemia/reperfusion (MCAO/R), explore the brain damage mechanism of MCAO/R at protein level, and provide experimental foundation for searching specific marker proteins of MCAO/R. Rat model of MCAO/R was established by modified suture-occluded method, and the model was evaluated by the results of brain 2,3,5-triphenyltetrazolium chloride (TTC) and hematoxylin-eosin (HE) staining. Cerebral cortex of rats from sham-operated group (Sham) and MCAO/R groups was used for FASP enzymatic hydrolysis, i-TRAQ quantitative labeling, and reverse-phase liquid chromatography purification and separation. Orbitrap Q Exactive mass spectrometry was used for qualitative and quantitative analyses of total differential protein expression profiles. MCAO/R rats had obvious cerebral infarction lesions, and the relative surface area of cerebral infarction was significantly different compared with sham rats, suggesting that MCAO/R rat model was successfully prepared. There were 199 significant difference proteins (MCAO/R vs Sham, p < 0.05, |fold change|> 1.2), including 104 up-regulated proteins and 95 down-regulated proteins. Gene ontology (GO) enrichment analysis showed that the up-regulated proteins were mainly concentrated in the biological processes of positive regulation of NF-κB transcription and I-κB kinase-NF-κB, etc. Down-regulated proteins were mainly concentrated in long-term synaptic potentiation, cellular response to DNA damage stimulus, etc. KEGG pathway analysis showed that the pathway involved in differential proteins includes oxidative phosphorylation, metabolic pathway, and Ras signaling pathway. Network analysis of differential proteins showed that Alb, ndufb5, ndufs7, ApoB, Cdc42, Ndufa3, Igf1r, P4hb, Mbp, Gc, Nme1, Akt2, and other proteins may play an important role in regulating oxidative stress, apoptosis, and inflammatory response in MCAO/R. Quantitative proteomics based on i-TRAQ labeling reveals the effect of inflammation and apoptosis in brain damage mechanism of MCAO/R. Besides, this research provide some experimental foundation for search and determination of potential therapeutic targets of MCAO/R.

Serum Albumin Levels in Severe Traumatic Brain Injury: Role as a Predictor of Outcome

Background Serum albumin has long been considered as an outcome marker in various critical illnesses. The aim of our study is to ascertain the role of serum albumin as a predictor of outcome in severe head injury patients.

Materials and Methods This is a prospective observational study of patients with severe traumatic brain injury (TBI). Depending on the serum albumin level at admission, patients were dichotomized into two groups: one with normal serum albumin and other with hypoalbuminemia. Their outcomes at 6-month follow-up were assessed by the modified Glasgow Outcome Score.

Result Eighty patients (57 males and 23 females) with severe TBI were included in the study. The mean age of the study patients was 39.6 + 13.1 years and the mean serum albumin level at admission was 3.7 + 1.2 g/dL with lowest being 2.2 mmol/L and highest being 6.1 mmol/L. Thirty-four patients (42.5%) had low serum albumin level (< 3.5 g/dL) at admission. At 6-month follow-up, 58 (72.5%) patients had a good neurological outcome and 22 (27.5%) had a poor outcome. The group with normal serum albumin levels showed a significantly better outcome compared with the hypoalbuminemia group (p = 0.01). On multiple regression analysis, low serum albumin emerged as the only predictor of the poor outcome in severe head injury patients.

Conclusion Serum albumin at admission is an independent predictor of outcome in severe TBI patients. Larger prospective studies are required to confirm these findings.

Prognostic Value of Serum Albumin at Admission for Neurologic Outcome with Targeted Temperature Management after Cardiac Arrest

Introduction

It is well known that hypoalbuminemia is associated with adverse outcomes in various critical illnesses. However, there are few studies specifically measuring the association between albumin level and neurologic outcomes after CA treated with TTM. The aim of this study was to assess whether serum albumin concentration on admission had prognostic value for OHCA patients treated with TTM.

Methods

We included adult patients aged ≥18 years with nontraumatic OHCA treated with TTM whose serum albumin concentration was available and who were admitted from 2009 to 2016. Serum albumin was measured within 1 h after ROSC, and hypoalbuminemia was defined as admission serum albumin <3.5 g/dl. A good neurologic outcome was defined as a cerebral performance category score of 1 or 2 at 6 months.

Results

A total of 255 patients were eligible for analysis, of whom 106 (41.6%) survived to 6 months; 84 (32.9%) of these patients achieved favorable neurologic outcomes. The mean albumin values were significantly lower in patients with poor neurologic outcomes than the values in those with good neurologic outcomes (3.3 ± 0.6 vs. 3.9 ± 0.4, respectively, p < 0.001). After adjusting the crude model, patients in the hypoalbuminemia group were 3.5 times more likely to have poor neurologic outcome than were those in the normal albumin group (OR 3.526, 95% CI 1.388–8.956, p=0.008).

Conclusions

Hypoalbuminemia was common after CA, and the serum albumin level at admission was associated with poor neurological outcomes at 6 months after CA in patients treated with TTM.

The relationship between plasma amino acids and circulating albumin and haemoglobin in postabsorptive stroke patients

Background

This retrospective study had two main aims: (1) to document possible correlations between plasma Amino Acids (AAs) and circulating Albumin (Alb) and Haemoglobin (Hb); and (2) to identify which AAs were predictors of Alb and Hb.

Methods

The study considered 125 stroke subjects (ST) (61.6% males; 65.6 +/- 14.9 years) who met the eligibility criteria (absence of co morbidities associated with altered plasma AAs and presence of plasma AAs determined after overnight fasting). Fifteen matched healthy subjects with measured plasma AAs served as controls.

Results

The best correlations of Alb were with tryptophan (Trp) and histidine (His) (r = + 0.53; p < 0.0001), and those of Hb were with histidine (r = +0.47) and Essential AAs (r = +0.47) (both p<0.0001). In multivariate analysis, Trp (p< 0.0001) and His (p = 0.01) were shown to be the best positive predictors of Alb, whereas glutamine (p = 0.006) was the best positive predictor of Hb.

Conclusions

The study shows that the majority of plasma AAs were positively correlated with Alb and Hb. The best predictors of circulating Alb and Hb were the levels of tryptophan and glutamine, respectively.

Human serum albumin attenuates global cerebral ischemia/reperfusion-induced brain injury in a Wnt/β-Catenin/ROS signaling-dependent manner in rats

This study sought to clarify the role and underlying mechanisms of human serum albumin (HSA) therapy in global cerebral ischemia/reperfusion (GCI/R)-induced brain damage in rats. Five groups of adult male Wistar rats (n = 12 per group) were created as follows: sham operation (Sham), global cerebral ischemia/reperfusion (GCI/R), HSA treatment (GCI/R + HSA), Dickkopf-1 (DDK1) treatment (GCI/R + DDK1), and DDK1 plus HSA treatment (GCI/R + DKK1 + HSA). The GCI/R injury model was created using the modified Pusinelli four-vessel occlusion method. After 24 h, rats were evaluated using neurological scoring, Nissl staining, and brain tissue water content. The mRNA expression of Wnt, GSK3β, and β-Catenin in the brain were detected by quantitative real time polymerase chain reaction. The protein expression of β-Catenin and GSK-3β were investigated by western blot and immunohistochemical analysis in the presence and absence of the Wnt/β-Catenin antagonist, DKK-1. Complex I activity and ROS content were also measured. After 24 h of reperfusion, the behavior score and brain tissue water content in the GCI/R + HSA group were lower than that in the GCI/R group. In addition, the degree of neuronal injury was significantly reduced in the GCI/R + HSA group (P < 0.05). The ROS content was significantly decreased and Complex I activity was markedly raised in the GCI/R + HSA group compared to the GCI/R group (P < 0.05). Further, GSK-3β expression in the GCI/R + HSA group was lower than that in the GCI/R group, while the Wnt and β-catenin expression were increased. These effects were reversed by DKK1. Taken together, we showed that HSA attenuates GCI/R-induced brain damage and may be neuroprotective via regulation of the Wnt/β-catenin/ROS signaling pathway.

A novel voxel-wise lesion segmentation technique on 3.0-T diffusion MRI of hyperacute focal cerebral ischemia at 1 h after permanent MCAO in rats

To assess hyperacute focal cerebral ischemia in rats on 3.0-Tesla diffusion-weighted imaging (DWI), we developed a novel voxel-wise lesion segmentation technique that overcomes intra- and inter-subject variation in apparent diffusion coefficient (ADC) distribution. Our novel technique involves the following: (1) intensity normalization including determination of the optimal type of region of interest (ROI) and its intra- and inter-subject validation, (2) verification of focal cerebral ischemic lesions at 1 h with gross and high-magnification light microscopy of hematoxylin-eosin (H&E) pathology, (3) voxel-wise segmentation on ADC with various thresholds, and (4) calculation of dice indices (DIs) to compare focal cerebral ischemic lesions at 1 h defined by ADC and matching H&E pathology. The best coefficient of variation was the mode of the left hemisphere after normalization using whole left hemispheric ROI, which showed lower intra- (2.54 ± 0.72%) and inter-subject (2.67 ± 0.70%) values than the original. Focal ischemic lesion at 1 h after middle cerebral artery occlusion (MCAO) was confirmed on both gross and microscopic H&E pathology. The 83 relative threshold of normalized ADC showed the highest mean DI (DI = 0.820 ± 0.075). We could evaluate hyperacute ischemic lesions at 1 h more reliably on 3-Tesla DWI in rat brains.

Inflammation and rehabilitation outcomes in patients with nontraumatic intracranial haemorrhage

BACKGROUND

Systemic inflammation and its impact on rehabilitation for patients with non-traumatic haemorrhagic injury (HBI) sequelae has not yet been adequately documented.

OBJECTIVE AND METHODS

We therefore considered 31 patients with HBI, to determine the serum levels of inflammatory markers (C-Reactive Protein, CRP and or interleukine-6, IL-6) to establish their impact on functional status (Functional Independence Measure, FIM: 18 indicating the worst performance and 126, a normal score).

RESULTS

The results showed an inflammation prevalence (CRP >0.5 mg/dl and/or IL 6 >7 pg/ml) of 74.2% at admission to Rehab. FIM reduction was more pronounced in inflamed compared to non-inflamed subjects (p <  0.05) and significantly correlated with blood variables sensitive to inflammation, such as alpha 1 globulin (r = - 0.565) and neutrophil/ lymphocyte ratio (r = - 0.52), CRP (r = - 0.365). At discharge from Rehab, the inflammation rate diminished. Inflamed patients showed similar gains in FIM score as their controls. In the entire population, the FIM gain was significantly associated with a gain in serum albumin, only (r = +0.56).

CONCLUSIONS

We conclude that systemic inflammation is prevalent in HBI patients and contributes to reduce patient functional status. However, during the Rehab stage, inflammation does not hinder the improvement rate of functional capacity.

Inflammation and rehabilitation outcomes in patients with nontraumatic intracranial haemorrhage

BACKGROUND

Systemic inflammation and its impact on rehabilitation for patients with non-traumatic haemorrhagic injury (HBI) sequelae has not yet been adequately documented.

OBJECTIVE AND METHODS

We therefore considered 31 patients with HBI, to determine the serum levels of inflammatory markers (C-Reactive Protein, CRP and or interleukine-6, IL-6) to establish their impact on functional status (Functional Independence Measure, FIM: 18 indicating the worst performance and 126, a normal score).

RESULTS

The results showed an inflammation prevalence (CRP >0.5 mg/dl and/or IL 6 >7 pg/ml) of 74.2% at admission to Rehab. FIM reduction was more pronounced in inflamed compared to non-inflamed subjects (p <  0.05) and significantly correlated with blood variables sensitive to inflammation, such as alpha 1 globulin (r = - 0.565) and neutrophil/ lymphocyte ratio (r = - 0.52), CRP (r = - 0.365). At discharge from Rehab, the inflammation rate diminished. Inflamed patients showed similar gains in FIM score as their controls. In the entire population, the FIM gain was significantly associated with a gain in serum albumin, only (r = +0.56).

CONCLUSIONS

We conclude that systemic inflammation is prevalent in HBI patients and contributes to reduce patient functional status. However, during the Rehab stage, inflammation does not hinder the improvement rate of functional capacity.

Mechanisms of lysophosphatidylcholine-induced demyelination: A primary lipid disrupting myelinopathy

For decades lysophosphatidylcholine (LPC, lysolecithin) has been used to induce demyelination, without a clear understanding of its mechanisms. LPC is an endogenous lysophospholipid so it may cause demyelination in certain diseases. We investigated whether known receptor systems, inflammation or nonspecific lipid disruption mediates LPC-demyelination in mice. We found that LPC nonspecifically disrupted myelin lipids. LPC integrated into cellular membranes and rapidly induced cell membrane permeability; in mice, LPC injury was phenocopied by other lipid disrupting agents. Interestingly, following its injection into white matter, LPC was cleared within 24 hr but by five days there was an elevation of endogenous LPC that was not associated with damage. This elevation of LPC in the absence of injury raises the possibility that the brain has mechanisms to buffer LPC. In support, LPC injury in culture was significantly ameliorated by albumin buffering. These results shed light on the mechanisms of LPC injury and homeostasis.

TGFβ signaling is associated with changes in inflammatory gene expression and perineuronal net degradation around inhibitory neurons following various neurological insults

Brain damage due to stroke or traumatic brain injury (TBI), both leading causes of serious long-term disability, often leads to the development of epilepsy. Patients who develop post-injury epilepsy tend to have poor functional outcomes. Emerging evidence highlights a potential role for blood-brain barrier (BBB) dysfunction in the development of post-injury epilepsy. However, common mechanisms underlying the pathological hyperexcitability are largely unknown. Here, we show that comparative transcriptome analyses predict remodeling of extracellular matrix (ECM) as a common response to different types of injuries. ECM-related transcriptional changes were induced by the serum protein albumin via TGFβ signaling in primary astrocytes. In accordance with transcriptional responses, we found persistent degradation of protective ECM structures called perineuronal nets (PNNs) around fast-spiking inhibitory interneurons, in a rat model of TBI as well as in brains of human epileptic patients. Exposure of a naïve brain to albumin was sufficient to induce the transcriptional and translational upregulation of molecules related to ECM remodeling and the persistent breakdown of PNNs around fast-spiking inhibitory interneurons, which was contingent on TGFβ signaling activation. Our findings provide insights on how albumin extravasation that occurs upon BBB dysfunction in various brain injuries can predispose neural circuitry to the development of chronic inhibition deficits.

The cerebral collateral circulation: Relevance to pathophysiology and treatment of stroke

The brain's collateral circulation consists of arterial anastomotic channels capable of providing nutrient perfusion to brain regions whose normal sources of flow have become compromised, as occurs in acute ischemic stroke. Modern CT-based neuroimaging is capable of providing detailed information as to collateral extent and sufficiency and is complemented by magnetic resonance-based methods. In the present era of standard-of-care IV thrombolysis for acute ischemic stroke, and following the recent therapeutic successes of randomized clinical trials of acute endovascular intervention, the sufficiency of the collateral circulation has been convincingly established as a key factor influencing the likelihood of successful reperfusion and favorable clinical outcome. This article reviews the features of the brain's collateral circulation; methods for its evaluation in the acute clinical setting; the relevance of collateral circulation to prognosis in acute ischemic stroke; the specific insights into the collateral circulation learned from recent trials of endovascular intervention; and the major influence of genetic factors. Finally, we emphasize the need to develop therapeutic approaches to augment collateral perfusion as an adjunctive strategy to be employed along with, or prior to, thrombolysis and endovascular interventions, and we highlight the possible potential of inhaled nitric oxide, albumin, and other approaches. This article is part of the Special Issue entitled 'Cerebral Ischemia'.

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

Albumin is known to have neuroprotective effects. The protein has a long half-life circulation, and its effects can therefore persist for a long time to aid in the recovery of brain ischemia. In the present study, we investigated the neuroprotective effects of human serum albumin (HSA) on brain hemodynamics. Albumin is administrated using repeated oral gavage to the rodents. Sprague-Dawley rats underwent middle cerebral artery occlusion procedures and served as a stroke model. Afterwards, 25% human serum albumin (1.25 g/kg) or saline (5 ml/kg) was orally administrated for 2 weeks in alternating days. After 2 weeks, the rodents were assessed for levels of brain ischemia. Our testing battery consists of behavioral tests and in vivo optical imaging sessions. Modified neurological severity scores (mNSS) were obtained to assess the levels of ischemia and the effects of HSA oral administration. We found that the experimental group demonstrated larger hemodynamic responses following sensory stimulation than controls that were administered with saline. HSA administration resulted in more significant changes in cerebral blood volume following direct cortical electric stimulation. In addition, the mNSS of the treatment group was lower than the control group. In particular, brain tissue staining revealed that the infarct size was also much smaller with HSA administration. This study provides support for the efficacy of HSA, and that long-term oral administration of HSA may induce neuroprotective effects against brain ischemia.

Transient cerebral ischemia induces albumin expression in microglia only in the CA1 region of the gerbil hippocampus

Albumin, the most abundant plasma protein, is known to exhibit a neuroprotective effect in animal models of focal and global cerebral ischemia. In the present study, the expression and immunoreactivity of albumin was examined in the hippocampus following 5 min of transient cerebral ischemia in gerbils. Albumin immunoreactivity was observed in microglia of the CA1 hippocampal region 2 days post-ischemic insult, and it was significantly increased at 4 days following ischemia-reperfusion. In addition, at 4 days post-ischemic insult, albumin-immunoreactive microglia were abundant in the stratum pyramidale of the CA1 region. The present results demonstrated that albumin was newly expressed post-injury in microglia in the CA1 region, suggesting ischemia-induced neuronal loss. Albumin expression may therefore be associated with ischemia-induced delayed neuronal death in the CA1 region following transient cerebral ischemia.

Expanding the concept of neuroprotection for acute ischemic stroke: The pivotal roles of reperfusion and the collateral circulation

This review surveys the efforts taken to achieve clinically efficacious protection of the ischemic brain and underscores the necessity of expanding our purview to include the essential role of cerebral perfusion and the collateral circulation. We consider the development of quantitative strategies to measure cerebral perfusion at the regional and local levels and the application of these methods to elucidate flow-related thresholds of ischemic viability and to characterize the ischemic penumbra. We stress that the modern concept of neuroprotection must consider perfusion, the necessary substrate upon which ischemic brain survival depends. We survey the major mechanistic approaches to neuroprotection and review clinical neuroprotection trials, focusing on those phase 3 multicenter clinical trials for acute ischemic stroke that have been completed or terminated. We review the evolution of thrombolytic therapies; consider the lessons learned from the initial, negative multicenter trials of endovascular therapy; and emphasize the highly successful positive trials that have finally established a clinical role for endovascular clot removal. As these studies point to the brain's collateral circulation as key to successful reperfusion, we next review the anatomy and pathophysiology of collateral perfusion as it relates to ischemic infarction, as well as the molecular and genetic influences on collateral development. We discuss the current MR and CT-based diagnostic methods for assessing the collateral circulation and the prognostic significance of collaterals in ischemic stroke, and we consider past and possible future therapeutic directions.

ALIAS (Albumin in Acute Ischemic Stroke) Trials: Analysis of the Combined Data From Parts 1 and 2

BACKGROUND AND PURPOSE

The ALIAS (Albumin in Acute Ischemic Stroke) part 1 and 2 trials evaluated whether 25% human serum albumin improves clinical outcomes after acute ischemic stroke above and beyond standard of care using similar protocols. The part 1 trial ended prematurely because of safety concerns, and the part 2 trial terminated early because of futility of finding a statistically significant effect of albumin over saline (control) administration. We combine the subject-level data of the part 1 and 2 trials to reevaluate the efficacy and safety outcomes with the larger sample size.

METHODS

The combined data analyses closely follow those conducted in the part 2 trial. The primary outcome is the composite of the modified Rankin Scale and the National Institutes of Health Stroke Scale defined as a composite of modified Rankin Scale score 0 to 1 and National Institutes of Health Stroke Scale score 0 to 1 at 90 days from randomization. The unadjusted analyses use a simple Chi-square test, and those adjusting for baseline covariates use a generalized linear model with log link (to obtain relative risks).

RESULTS

The participant characteristics at baseline were generally similar between the treatment groups and between the trials; however, thrombolysis use was greater in part 2 (84% versus 75%), and the upper age limit imposed in part 2 resulted in a younger sample (mean age in part 1 was 69 versus 64 in part 2). In the combined sample, the proportions of good outcome in the 2 treatment groups were identical (41%). Similar results were observed in all secondary efficacy outcomes. Pulmonary edema was a consistent safety concern, with a 6-fold increase in the albumin arm (13%) compared with saline (2%; relative risk =7.76, 95% confidence interval 3.87-15.57).

CONCLUSIONS

Treatment with intravenous albumin 25% at 2 g/kg was not associated with improved outcome at 90 days and was associated with increased rates of intracerebral hemorrhage and pulmonary edema.

CLINICAL TRIAL REGISTRATION

URL: https://www.clinicaltrials.gov. Unique identifier: NCT00235495.

Cerebral collateral circulation in experimental ischemic stroke

Cerebral collateral circulation is a subsidiary vascular network, which is dynamically recruited after arterial occlusion, and represents a powerful determinant of ischemic stroke outcome. Although several methods may be used for assessing cerebral collaterals in the acute phase of ischemic stroke in humans and rodents, they are generally underutilized. Experimental stroke models may play a unique role in understanding the adaptive response of cerebral collaterals during ischemia and their potential for therapeutic modulation. The systematic assessment of collateral perfusion in experimental stroke models may be used as a “stratification factor” in multiple regression analysis of neuroprotection studies, in order to control the within-group variability. Exploring the modulatory mechanisms of cerebral collaterals in stroke models may promote the translational development of therapeutic strategies for increasing collateral flow and directly compare them in term of efficacy, safety and feasibility. Collateral therapeutics may have a role in the hyperacute (even pre-hospital) phase of ischemic stroke, prior to recanalization therapies.

Serum Albumin and High-Sensitivity C-reactive Protein are Independent Risk Factors of Chronic Kidney Disease in Middle-Aged Japanese Individuals: the Circulatory Risk in Communities Study

Aim: It is important to explore predictive markers other than conventional cardiovascular risk factors for early detection and treatment of chronic kidney disease (CKD), a major risk factor for end-stage renal failure. We hypothesized that serum albumin and high-sensitivity C-reactive protein (hs-CRP) to be independent markers, and examined their associations with the risk of CKD.

Methods: We examined the associations of serum albumin and hs-CRP levels with the risk of incident CKD, in 2535 Japanese adults aged 40–69 years without CKD at baseline during a median 9.0-year follow-up after adjustment for known cardiovascular risk factors.

Results: During the follow-up period, 367 cases of CKD developed. In multivariable analyses adjusted for known risk factors, the CKD hazard ratios (95% confidence intervals) for the highest versus lowest quartiles of serum albumin levels were 0.69 (0.40–1.17) for men and 0.42 (0.28–0.64) for women. Corresponding values for hs-CRP were 0.95 (0.54–1.67) for men and 1.85 (1.25 -2.75) for women. The association of combined serum albumin and hs-CRP with the risk of CKD was examined for women. The hazard ratio was 1.72 (1.17–2.54) for low versus higher albumin levels at lower hs-CRP levels, but such an association was not observed at high hs-CRP level. The hazard ratio was 1.96 (1.44–2.66) for high versus lower hs-CRP levels at higher serum albumin levels, but such association was not observed at low serum albumin level.

Conclusion: Both low serum albumin and high hs-CRP levels were predictive of CKD for women.

Prognostic significance of serum albumin level changes in acute ischemic stroke: the role of biological and analytical variation

Animal studies have shown a neuroprotective effect of human serum albumin (sAlb) in ischemic stroke (IS). Previous studies have shown an association of high sAlb with better outcome. Our aim is to investigate the kinetics of sAlb in acute IS and its possible correlation with outcome taking into account the analytical and biological variation of sAlb measurement.

In a prospective observational study, we enrolled 105 patients with acute IS. sAlb was measured upon admission, at 24 h, 48 h, 72 h and Day 7 thereafter. Stroke severity was assessed upon admission and at 72 h, and functional outcome on Day 7. Patients were divided into two groups according to functional outcome on discharge. Calculation of reference change value was used to assess the clinical significance of sAlb changes and multiple logistic regression to assess the independent association between variables and outcome.

Fifty-one patients (48.6%) had poor outcome. Their sAlb levels exhibit a significant daily decrease until 72 h (35.9 g/L) compared to baseline (41.1 g/L) and remained low until Day 7 (36.0 g/L). These changes were clinically significant only from 72 h on. Among non-poor outcome patients a significant daily decrease until 72 h (40.9 g/L) was followed by recovery on Day 7 (41.2 g/L), but these changes were not clinically significant. sAlb was not independently associated with the functional outcome at any time-point.

This study shows that sAlb levels might change during the first days after an acute IS, but these changes although statistically significant are not clinically significant if we take into account the analytical and biological variation of sAlb.

Developing drug strategies for the neuroprotective treatment of acute ischemic stroke

Developing new treatment strategies for acute ischemic stroke in the last twenty years has offered some important successes, but also several failures. Most trials of neuroprotective therapies have been uniformly negative to date. Recent research has reported how excitatory amino acids act as the major excitatory neurotransmitters in the cerebral cortex and hippocampus. Furthermore, other therapeutic targets such as free radical scavenger strategies and the anti-inflammatory neuroprotective strategy have been evaluated with conflicting data in animal models and human subjects with acute ischemic stroke. Whereas promising combinations of neuroprotection and neurorecovery, such as citicoline, albumin and cerebrolysin have been tested with findings worthy of further evaluation in larger randomized clinical trials. Understanding the complexities of the ischemic cascade is essential to developing pharmacological targets for acute ischemic stroke in neuroprotective or flow restoration therapeutic strategies.

Albumin Administration in Acute Ischemic Stroke: Safety Analysis of the ALIAS Part 2 Multicenter Trial

BACKGROUND

Albumin treatment of ischemic stroke was associated with cardiopulmonary adverse events in previous studies and a low incidence of intracranial hemorrhage. We sought to describe the neurological and cardiopulmonary adverse events in the ALIAS Part 2 Multicenter Trial.

METHODS

Ischemic stroke patients, aged 18-83 and a baseline NIHSS ≥ 6, were randomized to treatment with ALB or saline control within 5 hours of stroke onset. Neurological adverse events included symptomatic intracranial hemorrhage, hemicraniectomy, neurological deterioration and neurological death. Cardiopulmonary adverse events included pulmonary edema/congestive heart failure, acute coronary syndromes, atrial fibrillation, pneumonia and pulmonary thromboembolism.

RESULTS

Among 830 patients, neurological and cardiopulmonary adverse events were not differentially associated with poor outcome between ALB and saline control subjects. The rate of symptomatic intracranial hemorrhage in the first 24h was low overall (2.9%, 24/830) but more common in the ALB treated subjects (RR = 2.4, CI95 1.01-5.8). The rate of pulmonary edema/CHF in the first 48h was 7.9% (59/830) and was more common among ALB treated subjects (RR = 10.7, CI95 4.3-26.6); this complication was expected and was satisfactorily managed with mandated diuretic administration and intravenous fluid guidelines. Troponin elevations in the first 48h were common, occurring without ECG change or cardiac symptoms in 52 subjects (12.5%).

CONCLUSIONS

ALB therapy was associated with an increase in symptomatic ICH and pulmonary edema/congestive heart failure but this did not affect final outcomes. Troponin elevation occurs routinely in the first 48 hours after acute ischemic stroke.

TRIAL REGISTRATION

ClincalTrials.gov NCT00235495.

Impaired leptomeningeal collateral flow contributes to the poor outcome following experimental stroke in the Type 2 diabetic mice

Collateral status is an independent predictor of stroke outcome. However, the spatiotemporal manner in which collateral flow maintains cerebral perfusion during cerebral ischemia is poorly understood. Diabetes exacerbates ischemic brain damage, although the impact of diabetes on collateral dynamics remains to be established. Using Doppler optical coherent tomography, a robust recruitment of leptomeningeal collateral flow was detected immediately after middle cerebral artery (MCA) occlusion in C57BL/6 mice, and it continued to grow over the course of 1 week. In contrast, an impairment of collateral recruitment was evident in the Type 2 diabetic db/db mice, which coincided with a worse stroke outcome compared with their normoglycemic counterpart db/+, despite their equally well-collateralized leptomeningeal anastomoses. Similar to the wild-type mice, both db/+ and db/db mice underwent collateral growth 7 d after MCA stroke, although db/db mice still exhibited significantly reduced retrograde flow into the MCA territory chronically. Acutely induced hyperglycemia in the db/+ mice did not impair collateral flow after stroke, suggesting that the state of hyperglycemia alone was not sufficient to impact collateral flow. Human albumin was efficacious in improving collateral flow and outcome after stroke in the db/db mice, enabling perfusion to proximal MCA territory that was usually not reached by retrograde flow from anterior cerebral artery without treatment. Our results suggest that the impaired collateral status contributes to the exacerbated ischemic injury in mice with Type 2 diabetes, and modulation of collateral flow has beneficial effects on stroke outcome among these subjects.

Effect of human albumin on TCD vasospasm, DCI, and cerebral infarction in subarachnoid hemorrhage: the ALISAH study

BACKGROUND AND PURPOSE

The neuroprotective effects of human albumin have been studied in animal models of stroke and in humans with various intracranial disorders. We investigated the effect of 25 % human albumin (ALB) on mean cerebral blood flow velocities (MCBFV), delayed cerebral ischemia (DCI), and cerebral infarction.

METHODS

We studied patients from the Albumin in Subarachnoid Hemorrhage (ALISAH) pilot clinical trial. We collected data on MCBFV as measured by transcranial Doppler ultrasound (TCD), incidence of DCI, and cerebral infarctions on head computed tomography (CT) scan at 90 days.

RESULTS

TCD showed vasospasm in 75 % (n = 15), 55 % (n = 11), and 29 % (n = 2) of subjects in dosage tiers 1, 2, and 3, respectively. DCI was present in 20 % (n = 4), 15 % (n = 3), and 14 % (n = 1) of subjects in dosage tiers 1, 2, and 3, respectively. Cerebral infarctions were seen in 45 % (5 of 9), 27 % (3 of 18), and 25 % (1 of 4) of subjects who had follow-up head CT scans in dosage tiers 1, 2, and 3, respectively.

CONCLUSIONS

Higher dosages of ALB were associated with a lower incidence of TCD vasospasm, DCI, and cerebral infarction at 90 days in a dose-dependent manner.

Neuroanesthesiology update

We review topics pertinent to the perioperative care of patients with neurological disorders. Our review addresses topics not only in the anesthesiology literature, but also in basic neurosciences, critical care medicine, neurology, neurosurgery, radiology, and internal medicine literature. We include literature published or available online up through December 8, 2013. As our review is not able to include all manuscripts, we focus on recurring themes and unique and pivotal investigations. We address the broad topics of general neuroanesthesia, stroke, traumatic brain injury, anesthetic neurotoxicity, neuroprotection, pharmacology, physiology, and nervous system monitoring.

Is stroke rehabilitation a metabolic problem?

BACKGROUND

This study looks at the impact of inflammation during the rehabilitation stage of strokes and its effect on neuro-functional recovery.

METHODS

This study investigated 94 patients suffering from strokes and admitted to rehabilitation. Anthropometric characteristics, serum proteins and inflammatory markers, plasma amino acids and neurofunction were all assessed.

RESULTS

55.3% patients had an inflammatory status (Interleukin-6 = 19.24 ± 23.01 pg ml⁻¹ vs. 4.1 ± 1.6 pg ml⁻¹ for non-inflamed subjects (p < 0.001). Inflammation was positively linked to positive proteins (alpha-1 globulin, p < 0.02) and negatively linked to negative proteins (albumin, p < 0.02; prealbumin, p < 0.01; transferrin, p < 0.05) of the acute-phase response. Inflammation was associated with low plasma concentrations of total amino acids. For the multiple logistic regression analysis, albumin (p < 0.001) and body weight maintenance (p < 0.001) were independent predictors of patient functional independence. Inflammation in dysphagic stroke (31.9%) patients was associated with more accentuated disability compared to non-inflamed dysphagics. The serum positive reactant alpha 1 globulin was the most powerful predictor of dysphagia severity (p < 0.001). At discharge, dysphagia improvement was associated with improved acute-phase negative proteins.

CONCLUSIONS

An inflammatory status may persist for most patients with strokes during the rehabiliation stage of the disease, its prevalence being higher in dysphagic compared to non-dysphagic subjects. The improvement in circulating albumin and body weight maintenance are predictors of neuro-function, even in dysphagic subjects.

Biomarkers for disease progression and AAV therapeutic efficacy in feline Sandhoff disease

The GM2 gangliosidoses, Tay-Sachs disease (TSD) and Sandhoff disease (SD), are progressive neurodegenerative disorders that are caused by a mutation in the enzyme β-N-acetylhexosaminidase (Hex). Due to the recent emergence of novel experimental treatments, biomarker development has become particularly relevant in GM2 gangliosidosis as an objective means to measure therapeutic efficacy. Here we describe blood, cerebrospinal fluid (CSF), magnetic resonance imaging (MRI), and electrodiagnostic methods for evaluating disease progression in the feline SD model and application of these approaches to assess AAV-mediated gene therapy. SD cats were treated by intracranial injections of the thalami combined with either the deep cerebellar nuclei or a single lateral ventricle using AAVrh8 vectors encoding feline Hex. Significantly altered in untreated SD cats, blood and CSF based biomarkers were largely normalized after AAV gene therapy. Also reduced after treatment were expansion of the lysosomal compartment in peripheral blood mononuclear cells and elevated activity of secondary lysosomal enzymes. MRI changes characteristic of the gangliosidoses were documented in SD cats and normalized after AAV gene therapy. The minimally invasive biomarkers reported herein should be useful to assess disease progression of untreated SD patients and those in future clinical trials.

Prognostic significance of ischemia-modified albumin in acute ischemic stroke patients: A preliminary study

Background

Ischemia-modified albumin (IMA) is a sensitive marker of ischemic event. However, limited studies are available regarding role of IMA in acute ischemic stroke (AIS).

Purpose

The aim of this study was to evaluate time course of IMA in AIS patient to validate its prognostic value.

Methods

IMA level was estimated in serum samples collected from five AIS patients at admission, 24hrs, 48hrs, 72hrs, and 144hrs after admission and also from five control subjects.

Results

There was significant (p<0.05) increase in IMA level in AIS samples at admission, 24hrs, 48hrs and 144hrs respectively when compared with control. On comparing IMA levels in follow up AIS samples with that of admission value we found that it decreased in follow-up samples till 72hrs, and significant (p<0.05) decrease was observed at 24hrs and 72hrs.

Conclusion

Findings shows that follow up estimation of IMA level in AIS may help in the prediction of the clinical status and outcome.

Serum albumin levels are associated with cardioembolic and cryptogenic ischemic strokes: Northern Manhattan Study

BACKGROUND AND PURPOSE

Low serum albumin concentrations have been associated with increased stroke risk, but the underlying mechanisms are less well studied. We aimed to investigate the association between serum albumin levels and ischemic stroke etiologies in a large, population-based, multiethnic, prospective, cohort study.

METHODS

Participants from the Northern Manhattan Study (NOMAS; n=2986; mean age, 69±10 years) free of stroke at baseline were followed for incident stroke (a median follow-up of 12 years). Cox proportional hazard models were used to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs) for baseline serum albumin levels and risk of ischemic stroke and ischemic stroke subtypes after adjusting for vascular risk factors.

RESULTS

The mean baseline serum albumin level was 4.42±0.33 g/dL. There were 271 ischemic strokes during follow-up. Participants with serum albumin levels of 2.7 to 4.2 g/dL (the lowest tertile) had increased risk of all stroke (HR, 1.76; 95% CI, 1.32-2.35), ischemic stroke (HR, 1.67; 95% CI, 1.21-2.29), cardioembolic stroke (HR, 1.92; 95% CI, 1.10-3.34), and cryptogenic stroke (HR, 2.59; 95% CI, 1.21-5.53), compared with those with levels of 4.6 to 5.5 g/dL (the top tertile; reference). Low albumin levels (2.7-4.2 g/dL) were not associated with large vessel or lacunar stroke.

CONCLUSIONS

Our study shows an association between low serum albumin levels and ischemic stroke, particularly cardioembolic and cryptogenic subtypes. These results suggest the potential shared pathophysiological relationship between low serum albumin levels, cardiac embolism, and cryptogenic infarction, which warrants further investigation.

Vascular remodeling after ischemic stroke: mechanisms and therapeutic potentials

The brain vasculature has been increasingly recognized as a key player that directs brain development, regulates homeostasis, and contributes to pathological processes. Following ischemic stroke, the reduction of blood flow elicits a cascade of changes and leads to vascular remodeling. However, the temporal profile of vascular changes after stroke is not well understood. Growing evidence suggests that the early phase of cerebral blood volume (CBV) increase is likely due to the improvement in collateral flow, also known as arteriogenesis, whereas the late phase of CBV increase is attributed to the surge of angiogenesis. Arteriogenesis is triggered by shear fluid stress followed by activation of endothelium and inflammatory processes, while angiogenesis induces a number of pro-angiogenic factors and circulating endothelial progenitor cells (EPCs). The status of collaterals in acute stroke has been shown to have several prognostic implications, while the causal relationship between angiogenesis and improved functional recovery has yet to be established in patients. A number of interventions aimed at enhancing cerebral blood flow including increasing collateral recruitment are under clinical investigation. Transplantation of EPCs to improve angiogenesis is also underway. Knowledge in the underlying physiological mechanisms for improved arteriogenesis and angiogenesis shall lead to more effective therapies for ischemic stroke.

Acute treatment with docosahexaenoic acid complexed to albumin reduces injury after a permanent focal cerebral ischemia in rats

Docosahexaenoic acid complexed to albumin (DHA-Alb) is highly neuroprotective after temporary middle cerebral artery occlusion (MCAo), but whether a similar effect occurs in permanent MCAo is unknown. Male Sprague-Dawley rats (270-330 g) underwent permanent MCAo. Neurological function was evaluated on days 1, 2 and 3 after MCAo. We studied six groups: DHA (5 mg/kg), Alb (0.63 or 1.25 g/kg), DHA-Alb (5 mg/kg+0.63 g/kg or 5 mg/kg+1.25 g/kg) or saline. Treatment was administered i.v. at 3 h after onset of stroke (n = 7-10 per group). Ex vivo imaging of brains and histopathology were conducted on day 3. Saline- and Alb-treated rats developed severe neurological deficits but were not significantly different from one another. In contrast, rats treated with low and moderate doses of DHA-Alb showed improved neurological score compared to corresponding Alb groups on days 2 and 3. Total, cortical and subcortical lesion volumes computed from T2 weighted images were reduced following a moderate dose of DHA-Alb (1.25 g/kg) by 25%, 22%, 34%, respectively, compared to the Alb group. The total corrected, cortical and subcortical infarct volumes were reduced by low (by 36-40%) and moderate doses (by 34-42%) of DHA-Alb treatment compared to the Alb groups. In conclusion, DHA-Alb therapy is highly neuroprotective in permanent MCAo in rats. This treatment can provide the basis for future therapeutics for patients suffering from ischemic stroke.

High-dose albumin treatment for acute ischaemic stroke (ALIAS) Part 2: a randomised, double-blind, phase 3, placebo-controlled trial

BACKGROUND

In animal models of ischaemic stroke, 25% albumin reduced brain infarction and improved neurobehavioural outcome. In a pilot clinical trial, albumin doses as high as 2 g/kg were safely tolerated. We aimed to assess whether albumin given within 5 h of the onset of acute ischaemic stroke increased the proportion of patients with a favourable outcome.

METHODS

We did a randomised, double-blind, parallel-group, phase 3, placebo-controlled trial between Feb 27, 2009, and Sept 10, 2012, at 69 sites in the USA, 13 sites in Canada, two sites in Finland, and five sites in Israel. Patients aged 18-83 years with ischaemic (ie, non-haemorrhagic) stroke with a baseline National Institutes of Health stroke scale (NIHSS) score of 6 or more who could be treated within 5 h of onset were randomly assigned (1:1), via a central web-based randomisation process with a biased coin minimisation approach, to receive 25% albumin (2 g [8 mL] per kg; maximum dose 750 mL) or the equivalent volume of isotonic saline. All study personnel and participants were masked to the identity of the study drug. The primary endpoint was favourable outcome, defined as either a modified Rankin scale score of 0 or 1, or an NIHSS score of 0 or 1, or both, at 90 days. Analysis was by intention to treat. Thrombolytic therapies were permitted. This trial is registered with ClinicalTrials.gov, number NCT00235495.

FINDINGS

422 participants were randomly assigned to receive albumin and 419 to receive saline. On Sept 12, 2012, the trial was stopped early for futility (n=841). The primary outcome did not differ between patients in the albumin group and those in the saline group (186 [44%] vs 185 [44%]; risk ratio 0·96, 95% CI 0·84-1·10, adjusted for baseline NIHSS score and thrombolysis stratum). Mild-to-moderate pulmonary oedema was more common in patients given albumin than in those given saline (54 [13%] of 412 vs 5 [1%] of 412 patients); symptomatic intracranial haemorrhage within 24 h was also more common in patients in the albumin group than in the placebo group (17 [4%] of 415 vs 7 [2%] of 414 patients). Although the rate of favourable outcome in patients given albumin remained consistent at 44-45% over the course of the trial, the cumulative rate of favourable outcome in patients given saline rose steadily from 31% to 44%.

INTERPRETATION

Our findings show no clinical benefit of 25% albumin in patients with ischaemic stroke; however, they should not discourage further efforts to identify effective strategies to protect the ischaemic brain, especially because of preclinical literature showing convincing proof-of-principle for the possibility of this outcome.

FUNDING

National Institute of Neurological Disorders and Stroke, US National Institutes of Health; and Baxter Healthcare Corporation.

Docosahexaenoic acid complexed to albumin provides neuroprotection after experimental stroke in aged rats

Recently we have shown that docosahexaenoic acid complexed to albumin (DHA-Alb) is neuroprotective after experimental stroke in young rats. The purpose of this study was to determine whether treatment with DHA-Alb would be protective in aged rats after focal cerebral ischemia. Isoflurane/nitrous oxide-anesthetized normothermic (brain temperature 36-36.5°C) Sprague-Dawley aged rats (18-months old) received 2h middle cerebral artery occlusion (MCAo) by poly-l-lysine-coated intraluminal suture. The neurological status was evaluated during occlusion (60min) and on days 1, 2, 3 and 7 after MCAo; a grading scale of 0-12 was employed. DHA (5mg/kg), Alb (0.63g/kg), DHA-Alb (5mg/kg+0.63g/kg) or saline was administered i.v. 3h after onset of stroke (n=8-10 per group). Ex vivo T2-weighted imaging (T2WI) of the brains was conducted on an 11.7T MRI on day 7 and 3D reconstructions were generated. Infarct volumes and number of GFAP (reactive astrocytes), ED-1 (activated microglia/microphages), NeuN (neurons)-positive cells and SMI-71 (positive vessels) were counted in the cortex and striatum at the level of the central lesion. Physiological variables were entirely comparable between groups. Animals treated with DHA-Alb showed significantly improved neurological scores compared to vehicle rats; 33% improvement on day 1; 39% on day 2; 41% on day 3; and 45% on day 7. Total and cortical lesion volumes computed from T2WI were significantly reduced by DHA-Alb treatment (62 and 69%, respectively). In addition, treatment with DHA-Alb reduced cortical and total brain infarction while promoting cell survival. We conclude that DHA-Alb therapy is highly neuroprotective in aged rats following focal cerebral ischemia and has potential for the effective treatment of ischemic stroke in aged individuals.

The pre-treatment effect on brain injury during restoration of normal perfusion pressure with hemodilution in a new rat model of chronic cerebral hypoperfusion

OBJECTIVES

To investigate the effect of hemodilution with high-concentration human serum albumin (HSA) on brain injury in a rat model of chronic cerebral hypoperfusion associated with arteriovenous malformations.

METHODS

The animal model was established by creating a fistula through an end-to-side anastomosis between the right distal external jugular vein and the ipsilateral common carotid artery, followed by ligation of the left vein draining the transverse sinus and bilateral external carotid arteries. The agent (20% HSA) or control solution (0.9% sodium chloride) was administered intravenously at a dosage of 1% body weight 24 hours before ligation of the fistula. Blood-brain barrier (BBB) disruption was judged by extravasation of Evans blue (EB) dye. EB, water content and the changes of myeloperoxidase (MPO) activity and superoxide dismutase (SOD) activity in rat brains 24 hours after ligation of the fistula were determined.

RESULTS

EB and water content in rat brains of the pre-treated group were significantly decreased compared with the control group accompanied by reduction of MPO activity and enhancement of SOD activity.

DISCUSSION

Hemodilution with high-concentration HSA has a certain pre-treatment effect on brain injury after ligation of the fistula in rat model of chronic cerebral hypoperfusion, which may be resulted from improved microcirculation, decrease in inflammatory cell infiltration and inactivation of oxygen free radicals.

Intraventricular albumin: an optional agent in experimental post-traumatic brain edema

HYPOTHESIS

Human albumin may be effective in the treatment of posttraumatic brain edema due to its hyperoncotic features. Therefore, the aim of the experimental study presented in this paper has two points: the first is to evaluate the efficacy of intraventricular hyperoncotic human albumin on post-traumatic brain edema and the second is to try to show the appropriate posttraumatic time window for albumin administration.

METHOD

Traumatic brain injury and subsequent edema was formed by a model of impact acceleration injury in rats. Human albumin was administered via intraventricular route by using a stereotactic head holder. All animals in each group were decapitated 24 hours after the procedure and the effect of albumin was evaluated by measurement of tissue specific gravity.

RESULTS

Tissue specific gravity decreased in edematous tissue (trauma indicator), increased after albumin administration at the 12th (p < 0.001), and both at the 1st and 12th hour of the trauma (edema treatment; p < 0.001). On the other hand, albumin administered at the 12th, and at both the 1st and 12th hours in the rats without trauma has caused the formation of the brain edema.

CONCLUSION

We conclude that human albumin is effective in cytotoxic, but not in vasogenic edema and exerts its best anti-edematous effect at the 12th hour of severe head trauma and this study may help future studies that will try to show the effects of albumin with different time modalities after severe head injury.

Serum albumin levels in ischemic stroke and its subtypes: correlation with clinical outcome

OBJECTIVE

Previous studies have associated low serum albumin levels with poor outcome in ischemic stroke. Animal studies also demonstrated neuroprotective effects of serum albumin in focal ischemia. However, there are very limited studies on the association of serum albumin levels with stroke outcome in ischemic stroke divided into subtypes. The present study was carried out to investigate the association of serum albumin levels with outcome in ischemic stroke and its subtypes.

METHODS

The study involved 560 patients. Serum albumin levels were estimated and follow-up interviews were conducted at 3 mo postevent to determine stroke outcome. The association between serum albumin levels and stroke outcome was evaluated by multiple logistic regression analysis after adjustment for potential confounders.

RESULTS

Low levels of albumin associated significantly with poor outcome (score of >3 on the modified Rankin Scale). The adjusted odds ratio was 1.972 (95% confidence interval, 1.103-4.001; P < 0.001). The recurrence of stroke and death rate also was high in patients with low levels of albumin compared with patients with elevated levels of albumin. The reduced level of serum albumin associated significantly with poor outcome in all the stroke subtypes classified according to TOAST (Trial of ORG 10172 in Acute Stroke Treatment).

CONCLUSIONS

Relatively high serum albumin levels in acute stroke decrease poor outcome.

Low admission serum albumin as prognostic determinant of 30-day case fatality and adverse functional outcome following acute ischemic stroke

Introduction

Over 80% of stroke deaths occur in low-income and middle-income regions of the world. Identification of predictors of mortality is vital so that prompt therapeutic measures could be instituted to improve outcome. Previous studies have identified factors such as stroke severity, stroke type, older age, impairment of consciousness and hyperglycaemia as predictors of mortality for acute stroke but mortality remain high among patients hospitalized for acute stroke. The study objective was to determine the association between admission serum albumin levels and short-term outcome following acute ischaemic stroke in Nigerians.

Methods

Consecutive first-ever acute ischaemic stroke patients were prospectively enrolled between February 2009 and May 2010. Stroke severity at presentation was determined using National Institute of Heath Stroke Score (NIHSS). Admission serum chemistry including albumin, were measured. Patients were then followed up for 30 days and outcome measures applied at the end of the study were 30-day mortality and functional outcome using the Modified Rankin Scale (MRS) and graded as favourable(MRS 0-3) or unfavourable(MRS 4-6). Relationship between serum albumin and stroke outcome was determined.

Results

75 acute stroke cases were studied. Mean age was 57.68 ± 12.4 years. Outcome was favourable in 48% while 30-day case fatality was 17.3%. The mean age (61.13 years) of those with poor outcome was significantly higher than those with favourable outcome. Mean serum albumin (3.03g/dL) of those with favourable outcome was also significantly higher than (2.08g/dL) of those with unfavourable outcome (p=0.0001). Patients that died had significantly lower serum albumin (1.66g/dl) than survivors (p=0.0001).Receiver operating characteristics curve for optimal cut off point of serum albumin to predict survival or death within 30 days revealed area under the cure (AUC) of 0.870, p-value 0.0001, 95% C/I=0.759-0.982. Serum albumin of 1.55g /dL has sensitivity of 100% and specificity of 61.5%. NIHSS and serum albumin were predictors of poor outcome using multiple regression.

Conclusion

Low admission serum albumin was an independent determinant of poor outcome.

Thrombin and hemin as central factors in the mechanisms of intracerebral hemorrhage-induced secondary brain injury and as potential targets for intervention

Intracerebral hemorrhage (ICH) is a subtype of stoke that may cause significant morbidity and mortality. Brain injury due to ICH initially occurs within the first few hours as a result of mass effect due to hematoma formation. However, there is increasing interest in the mechanisms of secondary brain injury as many patients continue to deteriorate clinically despite no signs of rehemorrhage or hematoma expansion. This continued insult after primary hemorrhage is believed to be mediated by the cytotoxic, excitotoxic, oxidative, and inflammatory effects of intraparenchymal blood. The main factors responsible for this injury are thrombin and erythrocyte contents such as hemoglobin. Therapies including thrombin inhibitors, N-methyl-D-aspartate antagonists, chelators to bind free iron, and antiinflammatory drugs are currently under investigation for reducing this secondary brain injury. This review will discuss the molecular mechanisms of brain injury as a result of intraparenchymal blood, potential targets for therapeutic intervention, and treatment strategies currently in development.

Albumin therapy enhances collateral perfusion after laser-induced middle cerebral artery branch occlusion: a laser speckle contrast flow study

Laser speckle contrast (LSC) was used to compare the extent of cortical ischemia in two inbred mouse strains that differed in their degree of collateral circulation, after laser occlusion of the distal middle cerebral artery, and after treatment with 25% albumin (ALB) or saline (control). Sequential LSC images acquired over ∼90 minutes were coaligned, converted to relative flow, and normalized to baseline. After 3-day survival, infarction was quantified by triphenyl tetrazolium chloride or magnetic resonance imaging. In the sparsely collateralized BALB/c strain, mean flow fell to 13% to 14% and 33% to 34% of baseline in central (core) and peripheral (penumbral) regions of interest, and ALB treatment at 30 minutes enhanced perfusion in both regions by ∼2-fold relative to saline, restoring flow to the benign-oligemic range centrally, and to the hyperemic range peripherally. The ALB-induced increment in parenchymal perfusion was disproportionate to the subtle flow increase in the occluded artery itself, suggesting that ALB improved collateral circulation. Cortical infarction in BALB/c mice was reduced 45% by ALB treatment. In contrast to BALB/c mice, the better-collateralized CD-1 strain developed milder ischemia, had smaller infarcts, and showed no differential benefit of ALB. We conclude that where native collateralization is insufficient (BALB/c strain), ALB treatment exerts a significant therapeutic effect after ischemia by augmenting collateral perfusion.