Dyslipidemic Diet Induces Mobilization of Peripheral Neutrophils and Monocytes That Exacerbate Hemorrhagic Brain Injury and Neuroinflammation

Gut microbiota alterations are associated with functional outcomes in patients of acute ischemic stroke with non-alcoholic fatty liver disease

Introduction

Patients with acute ischemic stroke (AIS) with non-alcoholic fatty liver disease (NAFLD) frequently have poor prognosis. Many evidences suggested that the changes in gut microbiota may play an important role in the occurrence and development of AIS patients with NAFLD. The purpose of this study was to explore microbial characteristics in patients of AIS with NAFLD, and the correlation between gut microbiota and functional outcomes.

Methods

The patients of AIS were recruited and divided into NAFLD group and non-NAFLD group. The stool samples and clinical information were collected. 16 s rRNA sequencing was used to analyze the characteristics of gut microbiota. The patients of AIS with NAFLD were followed-up to evaluate the functional outcomes of disease. The adverse outcomes were determined by modified Rankin scale (mRS) scores at 3 months after stroke. The diagnostic performance of microbial marker in predicting adverse outcomes was assessed by recipient operating characteristic (ROC) curves.

Results

Our results showed that the composition of gut microbiota between non-NAFLD group and NAFLD group were different. The characteristic bacteria in the patients of AIS with NAFLD was that the relative abundance of Dorea, Dialister, Intestinibacter and Flavonifractor were decreased, while the relative abundance of Enorma was increased. Moreover, the characteristic microbiota was correlated with many clinical parameters, such as mRS scores, mean arterial pressure and fasting blood glucose level. In addition, ROC models based on the characteristic microbiota or the combination of characteristic microbiota with independent risk factors could distinguish functional dependence patients and functional independence patients in AIS with NAFLD (area under curve is 0.765 and 0.882 respectively).

Conclusion

These findings revealed the microbial characteristics in patients of AIS with NAFLD, and further demonstrated the predictive capability of characteristic microbiota for adverse outcomes in patients of AIS with NAFLD.

Fatty liver and cerebrovascular disease: plausible association and possible mechanisms

PURPOSE OF REVIEW

Nonalcoholic fatty liver disease (NAFLD) is a common comorbidity and has wide ranging extrahepatic manifestations, including through cardiometabolic pathways. As such, there is growing interest in the impact of NAFLD on cerebrovascular disease and brain health more broadly. In this review, we assess recent research into understanding the association between NAFLD and brain health while highlighting potential clinical implications.

RECENT FINDINGS

Mechanistically, NAFLD is characterized by both a proinflammatory and proatherogenic state, which results in vascular inflammation and neurodegeneration, potentially leading to clinical and subclinical cerebrovascular disease. Mounting epidemiological evidence suggests an association between NAFLD and an increased risk and severity of stroke, independent of other vascular risk factors. Studies also implicate NAFLD in subclinical cerebrovascular disease, such as carotid atherosclerosis and microvascular disease. In contrast, there does not appear to be an independent association between NAFLD and cognitive impairment.

SUMMARY

The current literature supports the formulation of NAFLD as a multisystem disease that may also have implications for cerebrovascular disease and brain health. Further prospective studies are needed to better assess a temporal relationship between the two diseases, confirm these early findings, and decipher mechanistic links.

Novel targets, treatments, and advanced models for intracerebral haemorrhage

Intracerebral haemorrhage (ICH) is the second most common type of stroke and a major cause of mortality and disability worldwide. Despite advances in surgical interventions and acute ICH management, there is currently no effective therapy to improve functional outcomes in patients. Recently, there has been tremendous progress uncovering new pathophysiological mechanisms underlying ICH that may pave the way for the development of therapeutic interventions. Here, we highlight emerging targets, but also existing gaps in preclinical animal modelling that prevent their exploitation. We particularly focus on (1) ICH aetiology, (2) the haematoma, (3) inflammation, and (4) post-ICH pathology. It is important to recognize that beyond neurons and the brain, other cell types and organs are crucially involved in ICH pathophysiology and successful interventions likely will need to address the entire organism. This review will spur the development of successful therapeutic interventions for ICH and advanced animal models that better reflect its aetiology and pathophysiology.

Liver Fibrosis is Associated with Clinical Outcomes in Patients with Intracerebral Hemorrhage

BACKGROUND

Recent studies have reported the predictive value of liver fibrosis indices for hematoma enlargement in patients with intracerebral hemorrhage (ICH). However, little is known about the precise association between fibrosis and ICH prognosis. Thus, our study was designed to investigate the relevance of liver fibrosis, as evaluated by fibrosis-4 (FIB-4) score and poor outcomes after ICH.

METHODS

We used data from a prospective, multi-center and registry-based database. In this study, patients were stratified by the higher cut-off value of a FIB-4 score ≥2.67. The two groups of patients were then compared with regard to baseline characteristics, ICH severity and follow-up outcomes. We performed univariable and multivariable logistic regression analysis to determine the prognostic value of a FIB-4 score ≥2.67 for major disability or death. Kaplan-Meier survival curves were used to analyze the association between different FIB-4 scores and survival rate.

RESULTS

Our present study included 839 patients from 13 hospitals in Beijing. Participants with FIB-4 scores ≥2.67 had a larger baseline hematoma volume and a higher score on the modified Rankin Scale at follow-up (all p values <0.05). In the logistic regression analysis, liver fibrosis defined by a FIB-4 score ≥2.67 was independently associated with poor clinical outcomes at discharge and at 1 year (at discharge: adjusted odds ratio [95% CI] = 1.894 [1.120-3.202], p = 0.0172; at 1 year: adjusted odds ratio [95% CI] = 1.694 [1.021-2.809], p = 0.0412). However, this association was not observed at 3 months. During the follow-up period, patients with a FIB-4 score ≥2.67 also had a significantly lower survival rate according to Kaplan-Meier survival analysis.

CONCLUSION

Our study suggests that liver fibrosis defined by a FIB-4 score ≥2.67 is associated with poor clinical outcomes and lower survival rates in patients with mild to moderate ICH. These data provide reliable evidence for detecting fibrosis and managing related risk factors to improve prognosis after ICH.

Inhibition of exosome release augments neuroinflammation following intracerebral hemorrhage

Intracerebral hemorrhage (ICH) is a severe stroke subtype without effective pharmacological treatment. Following ICH, peripheral leukocytes infiltrate into the brain and contribute to neuroinflammation and brain edema. However, the intercellular machinery controlling the initiation and propagation of leukocyte infiltration remains elusive. Exosomes are small extracellular vesicles released from donor cells and bridge intercellular communication. In this study, we investigated the effects of inhibition of exosome release on neuroinflammation and ICH injury. Using a mouse model of ICH induced by collagenase injection, we found that ICH induced an increase of exosome level in the brain. Inhibition of exosome release using GW4869 augmented neurological deficits and brain edema after ICH. The exacerbation of ICH injury was accompanied by increased barrier disruption and brain infiltration of leukocytes. The detrimental effects of GW4869 were ablated in ICH mice receiving antibody depletion of Gr-1⁺ myeloid cells. Extracted exosomes from the ICH brains suppressed the production of inflammatory factors by splenocytes. Additionally, exosomes extracted from brain tissues of donor ICH mice reduced ICH injury in recipient mice. These results demonstrate that inhibition of exosome release augments neuroinflammation and ICH injury. The impact of exosomes released from the ICH brain on the immune system deserves further investigation.

Cognitive Dysfunction in Non-Alcoholic Fatty Liver Disease-Current Knowledge, Mechanisms and Perspectives

Non-alcoholic fatty liver disease (NAFLD) has emerged as the hepatic component of the metabolic syndrome and now seemingly affects one-fourth of the world population. Features associated with NAFLD and the metabolic syndrome have frequently been linked to cognitive dysfunction, i.e. systemic inflammation, vascular dysfunction, and sleep apnoea. However, emerging evidence suggests that NAFLD may be a cause of cognitive dysfunction independent of these factors. NAFLD in addition exhibits dysbiosis of the gut microbiota and impaired urea cycle function, favouring systemic ammonia accumulation and further promotes systemic inflammation. Such disruption of the gut–liver–brain axis is essential in the pathogenesis of hepatic encephalopathy, the neuropsychiatric syndrome associated with progressive liver disease. Considering the growing burden of NAFLD, the morbidity from cognitive impairment is expected to have huge societal and economic impact. The present paper provides a review of the available evidence for cognitive dysfunction in NAFLD and outlines its possible mechanisms. Moreover, the clinical challenges of characterizing and diagnosing cognitive dysfunction in NAFLD are discussed.