Obesity and stroke: Can we translate from rodents to patients?

The AGEs/RAGE Signaling Pathway Regulates NLRP3-Mediated Neuronal Pyroptosis After MCAO Injury in Lepr-/- Obese Rats

Background

Obesity is recognized as a primary risk factor for cerebral ischemia, which has shown a significant increase in its incidence among obese patients. The exact mechanism by which obesity exacerbates cerebral ischemic injury is not fully understood though. The present study validated the hypothesis that obesity mediates pyroptosis by the AGEs/RAGE signaling pathway to exacerbate cerebral ischemic injury.

Methods

Leptin receptor knockout (Lepr-/- ) rats were used in this study to construct an obesity model, and the middle cerebral artery occlusion (MCAO) models of ischemic stroke were established in Lepr-/- obese rats and their wild-type (WT) littermates respectively. Zea-Longa score, TTC and H&E staining were utilized to evaluate the neurological impairment. Western Blot, immunohistochemistry, and immunofluorescence were used to detect protein expressions. Transmission electron microscopy was used to observe the pores in the neuronal cell membrane in the ischemic penumbra cortex.

Results

Compared with WT littermates, Lepr-/- obese rats exhibited exacerbated neuronal injury after MCAO, with higher expressions of NLRP3 inflammasome and pyroptosis-related proteins in the cortical tissue of the penumbra. Moreover, more GSDMD pores were observed on the neuronal cell membranes of Lepr-/- obese rats according to the electron microscopy. Inhibition of NLRP3 inflammasome expression with MCC950 inhibited neuronal pyroptosis after cerebral ischemia in Lepr-/- obese rats, thus reducing neuronal injury. We also found that compared with WT littermates, the levels of AGEs and RAGE in the cortex of Lepr-/- obese rats are significantly higher, with further increase after cerebral ischemia. Inhibition of AGEs/RAGE signaling pathway with FPS-ZM1 reduced the NLRP3 inflammasome-mediated neuronal pyroptosis in Lepr-/- obese rats, thereby mitigating the neuronal damage after cerebral ischemia.

Conclusion

The AGEs/RAGE signaling pathway is involved in the exacerbation of cerebral ischemic injury in Lepr-/- obese rats via regulating NLRP3-mediated neuronal pyroptosis.

Early Cerebral Microvasculature Impairment and Increased Body Mass Index in Patients with Psoriasis

Psoriasis induces systemic atherosclerosis, but its impact on cerebrovascular function remains unclear. However, stroke prevention must be considered in psoriasis, as it is commonly comorbid with classic cardiovascular risk factors. Thus, the aim of the study is to assess cerebral microvasculature function and its confounders in patients with psoriasis. The study protocol included cerebral autoregulation assessment with measurements of vasomotor reactivity reserve (VMRr) on the middle cerebral arteries with the use of a Transcranial Doppler (TCD) in 50 patients with psoriasis without cerebrovascular events (46; 21-74 years) and 26 healthy controls (41; 29-58 years). Analyses of VMRr relationships with the psoriasis course, comorbidities, inflammatory markers and intima-media thickness (IMT) were performed. The study showed that VMRr was lower (64% vs. 76%, p = 0.001), and the IMT was higher (0.65 vs. 0.52 mm, p = 0.001) in patients compared to controls. The patients were also characterized by a higher body mass index (BMI) and a higher level of Il-6 than the controls (29.14 vs. 25.76 kg/m2, p = 0.004 and 585 vs. 204 pg/mL, p < 0.001, respectively), but only BMI was independently impacting VMRr reduction (p = 0.02). In conclusion, early cerebral microvasculature dysfunction may occur in patients with psoriasis, and its extent is associated with an increase in BMI. Thus, body mass reduction should be strongly recommended for stroke prophylaxis in patients with psoriasis.

Mechanistic correlation of molecular pathways in obesity-mediated stroke pathogenesis

Obesity, a prominent risk factor for the development of heart attacks and several cardiovascular ailments. Obesity ranks as the second most significant avoidable contributor to mortality, whereas stroke stands as the second leading cause of death on a global scale. While changes in lifestyle have been demonstrated to have significant impacts on weight management, the long-term weight loss remains challenging, and the global prevalence of obesity continues to rise. The pathophysiology of obesity has been extensively studied during the last few decades, and an increasing number of signal transduction pathways have been linked to obesity preclinically. This review is focused on signaling pathways, and their respective functions in regulating the consumption of fatty food as well as accumulation of adipose tissue, and the resulting morphological and cognitive changes in the brain of individuals with obesity. We have also emphasized the recent progress in the mechanisms behind the emergence of obesity, as elucidated by both experimental and clinical investigations. The mounting understanding of signaling transduction may shed light on the future course of obesity research as we move into a new era of precision medicine.

The role of digestive system diseases in cerebrovascular disease: a comprehensive Mendelian randomization study

Background

Cerebrovascular disease, among the most prevalent neurological disorders, poses a substantial threat to human health with its elevated mortality and disability rates, placing considerable strain on healthcare systems. Although several studies in recent years have suggested a potential association between digestive system diseases and cerebrovascular diseases, the findings remain inconsistent.

Methods

Genome-wide association study (GWAS) summary data for 12 digestive diseases and cerebrovascular diseases were used to conduct Mendelian randomization (MR) analysis. In this investigation, we endeavored to elucidate the causal relationship between digestive system diseases and cerebrovascular diseases. Employing a comprehensive approach, including two-sample MR (TSMR), multivariate MR (MVMR), and two-step MR analysis, we leveraged summary statistics data obtained from published GWAS. The primary analysis method employed was inverse variance weighted (IVW), with MR-Egger and weighted median (WM) as secondary methods. Sensitivity analysis included heterogeneity testing, horizontal multivariate testing, MR-PRESSO, and a "leave-one-out" method. Additionally, the F-statistic was utilized to assess the strength of instrumental variables, ensuring robust results.

Results

In the TSMR analysis, this study found a significant causal relationship between genetically predicted gastroesophageal reflux disease (GERD) and any stroke (AS), any ischemic stroke (AIS), large-artery atherosclerotic stroke (LAS), intracranial aneurysm (IA), and subarachnoid hemorrhage (SAH). In MVMR analysis, this study found that even after adjusting for systolic blood pressure (SBP), body mass index (BMI) and type 2 diabetes (T2D), the causal relationship remains exist. In the two-step MR mediation analysis, it was found that BMI, SBP and T2D play mediating role in the causal relationship between GERD and cerebrovascular diseases.

Conclusion

This study indicates a clear positive causal relationship between GERD and cerebrovascular diseases, and this causal association remains significant even after adjusting for BMI, SBP and T2D. The mediation MR analysis suggests that BMI, SBP and T2D may mediate the causal relationship between GERD and the risk of cerebrovascular diseases.

Obesity-induced blood-brain barrier dysfunction: phenotypes and mechanisms

Obesity, a burgeoning global health issue, is increasingly recognized for its detrimental effects on the central nervous system, particularly concerning the integrity of the blood-brain barrier (BBB). This manuscript delves into the intricate relationship between obesity and BBB dysfunction, elucidating the underlying phenotypes and molecular mechanisms. We commence with an overview of the BBB's critical role in maintaining cerebral homeostasis and the pathological alterations induced by obesity. By employing a comprehensive literature review, we examine the structural and functional modifications of the BBB in the context of obesity, including increased permeability, altered transport mechanisms, and inflammatory responses. The manuscript highlights how obesity-induced systemic inflammation and metabolic dysregulation contribute to BBB disruption, thereby predisposing individuals to various neurological disorders. We further explore the potential pathways, such as oxidative stress and endothelial cell dysfunction, that mediate these changes. Our discussion culminates in the summary of current findings and the identification of knowledge gaps, paving the way for future research directions. This review underscores the significance of understanding BBB dysfunction in obesity, not only for its implications in neurodegenerative diseases but also for developing targeted therapeutic strategies to mitigate these effects.

Adiposity and Functional Outcome After Ischemic Stroke: A Mendelian Randomization Study

BACKGROUND AND OBJECTIVES

To investigate the causal relationships of abdominal adiposity (waist-to-hip ratio [WHR]) and overall adiposity (body mass index [BMI]) with functional outcome after ischemic stroke using Mendelian randomization.

METHODS

Genetic instruments for WHR and BMI were obtained from the largest available genome-wide association studies meta-analysis of the Genetic Investigation of ANthropometric Traits consortium and the UK Biobank (N max = 806,834). Functional outcome after ischemic stroke was assessed using the modified Rankin Scale (mRS) score at 3-month after stroke onset, with mRS >2 (mRS 3-6) defined as an unfavorable functional outcome. Corresponding genetic estimates for an unfavorable functional outcome were extracted from the Genetics of Ischemic Stroke Functional Outcome network (N = 6,021). We applied a random-effects inverse variance weighted method as our main analysis.

RESULTS

Genetically predicted higher WHR (per 0.09 ratio units) was associated with unfavorable functional outcome after ischemic stroke (mRS 3-6, OR = 1.48; 95% CI = 1.03-2.13; p = 0.033). The results remained directionally consistent in sensitivity analyses. Conversely, genetically predicted BMI (per 4.8 kg/m2) was not associated with unfavorable functional outcome after ischemic stroke (OR = 1.01; 95% CI = 0.75-1.36; p = 0.937).

DISCUSSION

This study provides genetic evidence supporting the hypothesis that abdominal adiposity has a detrimental effect on functional recovery after ischemic stroke.

Melatonin modulates the aggravation of pyroptosis, necroptosis, and neuroinflammation following cerebral ischemia and reperfusion injury in obese rats

Obesity is well-established as a common comorbidity in ischemic stroke. The increasing evidence has revealed that it also associates with the exacerbation of brain pathologies, resulting in increasingly severe neurological outcomes following cerebral ischemia and reperfusion (I/R) damage. Mechanistically, pyroptosis and necroptosis are novel forms of regulated death that relate to the propagation of inflammatory signals in case of cerebral I/R. Previous studies noted that pyroptotic and necroptotic signaling were exacerbated in I/R brain of obese animals and led to the promotion of brain tissue injury. This study aimed to investigate the roles of melatonin on pyroptosis, necroptosis, and pro-inflammatory pathways occurring in the I/R brain of obese rats. Male Wistar rats were given a high-fat diet for 16 weeks to induce the obese condition, and then were divided into 4 groups: Sham-operated, I/R treated with vehicle, I/R treated with melatonin (10 mg/kg), and I/R treated with glycyrrhizic acid (10 mg/kg). All drugs were administered via intraperitoneal injection at the onset of reperfusion. The development of neurological deficits, cerebral infarction, histological changes, neuronal death, and glial cell hyperactivation were investigated. This study revealed that melatonin effectively improved these detrimental parameters. Furthermore, the processes of pyroptosis, necroptosis, and inflammation were all diminished by melatonin treatment. A summary of the findings is that melatonin effectively reduces ischemic brain pathology and thereby improves post-stroke outcomes in obese rats by modulating pyroptosis, necroptosis, and inflammation.

Modifiable risk factors that mediate the effect of educational attainment on the risk of stroke: a network Mendelian randomization study

BACKGROUND

Stroke is a common cerebrovascular disease with great danger to public health. Educational inequality is a universal issue that influences populations' stroke risk. This study aimed to investigate the causal relationship between education and stroke risk and the contributions of effects mediated by four modifiable factors.

MATERIALS AND METHODS

Public large-scale genome-wide association study (GWAS) summary data associated with educational attainment, hypertensive diseases, body mass index (BMI), smoking behavior, time spent on watching the television (TV), and stroke were obtained from European ancestry. The data were used to investigate the causal relationship among educational attainment, hypertensive disease, BMI, smoking, watching TV, and stroke risk. Inverse variance weighted (IVW) method was used as a primary algorithm for estimating causal direction and effect size in univariable and multivariable Mendelian randomization (MR) analyses.

RESULTS

Higher educational attainment was a causal protective factor, while hypertensive diseases, higher BMI, smoking, and longer time spent on watching the TV were all causal risk factors for the risk of stroke. Hypertensive disease, BMI, smoking, and watching TV were all mediators for linking the causal relationship between educational attainment and stroke risk. Hypertensive disease, BMI, smoking, and watching TV explained 47.35%, 24.74%, 15.72%, and 2.29% of the variance in educational attainment's effect on stroke risk, respectively. The explained proportion reached 69.32% after integrating the four factors.

CONCLUSIONS

These findings support the causal effect of educational attainment on the risk of stroke, with a substantial proportion mediated by modifiable risk factors. Interventions on these modifiable factors would lead to substantial reductions in stroke cases attributable to educational inequality.

Potential Benefits of Antioxidant Phytochemicals on Endogenous Antioxidants Defences in Chronic Diseases

Chronic diseases and cancer are worldwide health problems which result in death and disability for millions of people [...]

Does bariatric surgery change the risk of acute ischemic stroke in patients with a history of transient ischemic attack? A nationwide analysis

BACKGROUND

Stroke is the second leading cause of death worldwide and fifth in the United States, and it represents the major cause of disability in older adults.

OBJECTIVE

We aimed to determine the risk of acute ischemic stroke (AIS) in individuals with obesity with a history of transient ischemic attack (TIA) compared with patients with a history of bariatric surgery.

SETTING

Academic hospital, United States.

METHODS

Using the Nationwide Inpatient Sample (NIS) database from 2010 to 2015, we retrospectively identified patients with obesity and past medical history of TIA and divided them into 2 groups: a treatment group of patients who underwent bariatric surgery, and a control group of patients with obesity. We compared incidence of new AIS in both groups using a univariate analysis and multivariate regression model. Covariates included were lifestyle (smoking status, alcohol habits, cocaine use), family history of stroke, co-morbidities (diabetes, hypertension, hyperlipidemia, atrial fibrillation) and long-term medical treatment (antiplatelet/antithrombotic treatment).

RESULTS

A total of 91,640 patients met inclusion criteria, of which treatment patients were 12.3% (n = 11,284) and control patients 87.6% (n = 80,356). The average age of the treatment group was 62.9 ± 17.08 years, and the average of the control was 59.6 ± 12.74 years. The rate of AIS in the treatment group was significantly lower compared with the control group (2.8% versus 4.2%, P < .0001). After adjusting for covariables, the risk difference of AIS was still significant between groups (odds ratio = 1.33, P < .0001), showing that patients in the treatment group were less likely to have AIS compared with the control group.

CONCLUSIONS

After analyzing nationwide information, we conclude bariatric surgery helps decrease risk of AIS in patients with a history of TIA. However, this comparison is limited by the nature of the database; further studies are needed to better understand these results.

The epidemic of stroke mortality attributed to high body mass index in mainland China: Current trends and future prediction

Background

High body mass index (BMI) is an important risk factor for stroke. The aim of this study was to assess the long-term trend of high BMI-attributed stroke mortality and make projections through 2030.

Methods

Data were extracted from the Global Burden of Disease Study 2019 and World Population Prospects 2019. An age-period-cohort framework was used in the analysis.

Results

From 1990 to 2019, the age-standardized mortality rate (ASMR) of high BMI-attributed stroke among females decreased by 15.2%, while among males, it increased by 31.1%. All of the age groups studied showed an increasing pattern over the last 30 years in males, and in female, the age groups encompassing participants who were 25-69 years old showed a decreasing pattern. In the same birth cohort, high BMI-attributable stroke mortality rates increased exponentially with age in both sexes. For females, the period rate ratios (RR) showed a downward trend after 2000-2004, and the cohort RR also showed a downward trend after the birth cohort 1930-1934. For males, the period RR showed an upward trend, but this increase was halted in the most recent period, and the cohort RRs showed a monotonic increasing pattern. It was projected that the ASMR of high BMI-attributed stroke would decrease among females and increase among males in the near future and that the proportion of elderly individuals with death due to high BMI-attributed stroke was projected to increase.

Conclusions

Over the last three decades, the high BMI-attributed stroke mortality rate decreased among females and increased among males, and these trends are projected to continue in the future. In addition, the proportion of elderly individuals with high BMI-attributed stroke mortality was projected to increase gradually in both men and women. More health-promoting efforts are needed, especially for elderly individuals and males.

MMPP promotes adipogenesis and glucose uptake via binding to the PPARγ ligand binding domain in 3T3-L1 MBX cells

Peroxisome proliferator-activated receptor-gamma (PPARγ) is a transcription factor involved in adipogenesis, and its transcriptional activity depends on its ligands. Thiazolidinediones (TZDs), well-known PPARγ agonists, are drugs that improve insulin resistance in type 2 diabetes. However, TZDs are associated with severe adverse effects. As current therapies are not well designed, novel PPARγ agonists have been investigated in adipocytes. (E)-2-methoxy-4-(3-(4-methoxyphenyl) prop-1-en-1-yl) phenol (MMPP) is known to have anti-arthritic, anti-inflammatory, and anti-cancer effects. In this study, we demonstrated the adipogenic effects of MMPP on the regulation of PPARγ transcriptional activity during adipocyte differentiation in vitro. MMPP treatment increased PPARγ transcriptional activity, and molecular docking studies revealed that MMPP binds directly to the PPARγ ligand binding domain. MMPP and rosiglitazone showed similar binding affinities to the PPARγ. MMPP significantly promoted lipid accumulation in adipocyte cells and increased the expression of C/EBPβ and the levels of p-AKT, p-GSK3, and p-AMPKα at an early stage. MMPP enhanced the expression of adipogenic markers such as PPARγ, C/EBPα, FAS, ACC, GLUT4, FABP4 and adiponectin in the late stage. MMPP also improved insulin sensitivity by increasing glucose uptake. Thus, MMPP, as a PPARγ agonist, may be a potential drug for type 2 diabetes and metabolic disorders, which may help increase adipogenesis and insulin sensitivity.

Ischemic Stroke, Lessons from the Past towards Effective Preclinical Models

Ischemic stroke is a leading cause of death worldwide, mainly in western countries. So far, approved therapies rely on reperfusion of the affected brain area, by intravenous thrombolysis or mechanical thrombectomy. The last approach constitutes a breakthrough in the field, by extending the therapeutic window to 16-24 h after stroke onset and reducing stroke mortality. The combination of pharmacological brain-protective strategies with reperfusion is the future of stroke therapy, aiming to reduce brain cell death and decrease patients' disabilities. Recently, a brain-protective drug-nerinetide-reduced brain infarct and stroke mortality, and improved patients' functional outcomes in clinical trials. The success of new therapies relies on bringing preclinical studies and clinical practice close together, by including a functional outcome assessment similar to clinical reality. In this review, we focused on recent upgrades of in vitro and in vivo stroke models for more accurate and effective evaluation of therapeutic strategies: from spheroids to organoids, in vitro models that include all brain cell types and allow high throughput drug screening, to advancements in in vivo preclinical mouse stroke models to mimic the clinical reality in surgical procedures, postsurgical care, and functional assessment.

Obesity induces extracellular vesicle release from the endothelium as a contributor to brain damage after cerebral ischemia in rats

OBJECTIVES

Cerebral ischemia is the most common cause of disability, the second most common cause of dementia, and the fourth most common cause of death in the developed world [Sveinsson OA, Kjartansson O, Valdimarsson EM. Heilablóðþurrð/heiladrep: Faraldsfræði, orsakir og einkenni [Cerebral ischemia/infarction - epidemiology, causes and symptoms]. Laeknabladid. 2014 May;100(5):271-9. Icelandic. doi:10.17992/lbl.2014.05.543]. Obesity has been associated with worse outcomes after ischemia in rats, triggering proinflammatory cytokine production related to the brain microvasculature. The way obesity triggers these effects remains mostly unknown. Therefore, the aim of this study was to elucidate the cellular mechanisms of damage triggered by obesity in the context of cerebral ischemia.

METHODS

We used a rat model of obesity induced by a 20% high fructose diet (HFD) and evaluated peripheral alterations in plasma (lipid and cytokine profiles). Then, we performed cerebral ischemia surgery using two-vessel occlusion (2VO) and analyzed neurological/motor performance and glial activation. Next, we treated endothelial cell line cultures with glutamate in vitro to simulate an excitotoxic environment, and we added 20% plasma from obese rats. Subsequently, we isolated EVs released from endothelial cells and treated primary cultures of astrocytes with them.

RESULTS

Rats fed a HFD had an increased BMI with dyslipidemia and high levels of proinflammatory cytokines. Glia from the obese rats exhibited altered morphology, suggesting hyperreactivity related to neurological and motor deficits. Plasma from obese rats induced activation of endothelial cells, increasing proinflammatory signals and releasing more EVs. Similarly, these EVs caused an increase in NF-κB and astrocyte cytotoxicity. Together, the results suggest that obesity activates proinflammatory signals in endothelial cells, resulting in the release of EVs that simultaneously contribute to astrocyte activation.

Antioxidant Polyphenols of Antirhea borbonica Medicinal Plant and Caffeic Acid Reduce Cerebrovascular, Inflammatory and Metabolic Disorders Aggravated by High-Fat Diet-Induced Obesity in a Mouse Model of Stroke

Metabolic disorders related to obesity and type 2 diabetes are associated with aggravated cerebrovascular damages during stroke. In particular, hyperglycemia alters redox and inflammatory status, leading to cerebral endothelial cell dysfunction, blood–brain barrier (BBB) disruption and brain homeostasis loss. Polyphenols constitute the most abundant dietary antioxidants and exert anti-inflammatory effects that may improve cerebrovascular complications in stroke. This study evaluated the effects of the characterized polyphenol-rich extract of Antirhea borbonica medicinal plant and its major constituent caffeic acid on a high-fat diet (HFD)-induced obesity mouse model during ischemic stroke, and murine bEnd3 cerebral endothelial cells in high glucose condition. In vivo, polyphenols administered by oral gavage for 12 weeks attenuated insulin resistance, hyperglycemia, hyperinsulinemia and dyslipidemia caused by HFD-induced obesity. Polyphenols limited brain infarct, hemorrhagic transformation and BBB disruption aggravated by obesity during stroke. Polyphenols exhibited anti-inflammatory and antioxidant properties by reducing IL-1β, IL-6, MCP-1, TNF-α and Nrf2 overproduction as well as total SOD activity elevation at the cerebral or peripheral levels in obese mice. In vitro, polyphenols decreased MMP-2 activity that correlated with MCP-1 secretion and ROS intracellular levels in hyperglycemic condition. Protective effects of polyphenols were linked to their bioavailability with evidence for circulating metabolites including caffeic acid, quercetin and hippuric acid. Altogether, these findings show that antioxidant polyphenols reduced cerebrovascular, inflammatory and metabolic disorders aggravated by obesity in a mouse model of stroke. It will be relevant to assess polyphenol-based strategies to improve the clinical consequences of stroke in the context of obesity and diabetes.

Body mass index, blood glucose, and mortality in patients with ischemic stroke in the intensive care unit: A retrospective cohort study

BACKGROUND

Excessive BMI was associated with lower mortality after stroke. However, some believed that excessive BMI can lead to a poor prognosis because of some physiological mechanism, such as glucose metabolism disorder. Therefore, this study aims to discuss the association between mortality, BMI, and blood glucose.

MATERIALS AND METHODS

This was a retrospective observational study and all data were extracted from the Medical Information Mart for Intensive Care III database. The exposure was BMI classified into the normal weight group and the excessive weight group. The outcome concluded 30-day, 90-day, and 1-year mortality. The association between two groups and mortality was elucidated by Cox regression models, propensity score matching (PSM) and inverse probability of treatment weighting (IPTW). The underlying effect of blood glucose on the "obesity paradox" was analyzed by causal mediation analysis.

RESULTS

According to Cox regression models, a significant beneficial effect of excessive BMI in terms of mortality was observed: 30-day mortality (HR 0.57, 95% CI 0.35-0.90, P = 0.017), 90-day mortality (HR 0.53, 95% CI 0.36-0.78, P = 0.001), and 1-year mortality (HR 0.65, 95% CI 0.46-0.91, P = 0.013). After PSM and IPTW, we got a similar conclusion. The causal mediation analysis showed that the protective effect of excessive BMI on 30-day mortality reduced with the increase of blood glucose.

CONCLUSION

For ischemic stroke patients in the Intensive Care Unit, those with excessive BMI are associated with both lower short-term mortality and lower long-term mortality, while the protective effect on 30-day mortality weakened accompanied by the increase of blood glucose.

Nuciferine, an active ingredient derived from lotus leaf, lights up the way for the potential treatment of obesity and obesity-related diseases

Obesity, is an increasingly global public health problem associated complications. However, the proven anti-obesity agents are inefficient with adverse side effects; hence attention is being paid to novel drugs from natural resources to manage obesity and obesity-related diseases. Nuciferine (NF) is a high-quality aporphine alkaloid present in lotus leaf. Unlike the chemical drugs, NF elicits anti-obesity, anti-dyslipidemia, anti-hyperglycemic, anti-hypouricemic, anti-inflammatory, and anti-tumor effects, and affinity to neural receptors, and protection against obesity-related diseases. The underlying mechanism of NF includes the regulation of targeted molecules and pathways related to metabolism, inflammation, and cancer and modulation of Ca²⁺ flux, gut microbiota, and ferroptosis. Besides, the clinical application, availability, pharmacokinetics, pharmaceutics, and security of NF have been established, highlighting the potential of developing NF as an anti-obesity agent. Therefore, this review provides a comprehensive summarization, which sheds light on future research in NF.

High-Fat Diet Aggravates Cerebral Infarct, Hemorrhagic Transformation and Neuroinflammation in a Mouse Stroke Model

BACKGROUND

Stroke in context of type 2 diabetes (T2D) is associated with a poorer outcome than in non-diabetic conditions. We aimed at creating a new reproducible mouse model of stroke in impaired glucose tolerance conditions induced by high-fat diet.

METHODS

Adult C57BL6 mice were fed for 2 months with either normal diet (ND) or high-fat diet (HFD). We used a model of Middle Cerebral Artery Occlusion (MCAO) for 90 min. Oral Glucose Tolerance Test (OGTT) and Insulin Tolerance Test (ITT) were used to assess pre-diabetic status. Brain infarct volume, hemorrhagic transformation (HT) as well as systemic and cerebral inflammatory markers were evaluated.

RESULTS

HFD was associated with an increased body weight and glycemia following OGTT. The HFD group presented a significant increase in brain infarct volume (38.7 (IQR 30-46.7%) vs. 28.45 (IQR 21-30%); p = 0.016) and HT (HFD: 2 (IQR 1-5) vs. ND: 0 (IQR 0-1); p = 0.012) and higher levels of IL-6 and MCP-1 in infarcted hemisphere compared to the ND group.

CONCLUSION

Two months of HFD in adult mice were sufficient to alter the lipid profile and the control of hyperglycemia. These metabolic perturbations were significantly associated with increased infarct volume and hemorrhagic complications.

Obesity and Stroke: Does the Paradox Apply for Stroke?

Historically, obesity has been identified as one of the most important risk factors for developing cardiovascular diseases including stroke; however, a theory called "The Obesity Paradox" has been recently considered. The paradoxical theory is that obese or overweight patients (according to body mass index score) can have better outcomes compared to leaner or malnourished patients. The paradox was initially discovered in patients with heart failure. The purpose of this manuscript was to investigate whether this paradox also applies to stroke patients, according to information available in the current literature.

Clarifying the effects of diabetes on the cerebral circulation: Implications for stroke recovery and beyond

Given the sheer increased number of victims per year and the availability of only one effective treatment, acute ischemic stroke (AIS) remains to be one of the most under-treated serious diseases. Diabetes not only increases the incidence of ischemic stroke, but amplifies the ischemic damage, upon which if patients with diabetes suffer from stroke, he/she will confront increased risks of long-term functional deficits. The grim reality makes it a pressing need to intensify efforts at the basic science level to understand how diabetes impairs stroke recovery. This review retrospects the clinical and experimental studies in order to elucidate the detrimental effect of diabetes on cerebrovascular circulation including the major arteries/arterioles, collateral circulation, and neovascularization to shed light on further exploration of novel strategies for cerebral circulation protection before and after AIS in patients with diabetes.

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

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

Ischemic stroke, obesity, and the anti-inflammatory role of melatonin

Obesity is a predominant risk factor in ischemic stroke and is commonly comorbid with it. Pathologies following these conditions are associated with systemic and local inflammation. Moreover, there is increasing evidence that the susceptibility for ischemic brain damage increases substantially in experimental models of ischemic stroke with concomitant obesity. Herein, we explore the proinflammatory events that occur during ischemic stroke and obesity, and we discuss the influence of obesity on the inflammatory response and cerebral damage outcomes in experimental models of brain ischemia. In addition, because melatonin is a neurohormone widely reported to exhibit protective effects in various diseases, this study also demonstrates the anti-inflammatory role and possible mechanistic actions of melatonin in both epidemic diseases. A summary of research findings suggests that melatonin administration has great potential to exert an anti-inflammatory role and provide protection against obesity and ischemic stroke conditions. However, the efficacy of this hormonal treatment on ischemic stroke with concomitant obesity, when more serious inflammation is generated, is still lacking.

Filling the gaps on stroke research: Focus on inflammation and immunity

For the last two decades, researchers have placed hopes in a new era in which a combination of reperfusion and neuroprotection would revolutionize the treatment of stroke. Nevertheless, despite the thousands of papers available in the literature showing positive results in preclinical stroke models, randomized clinical trials have failed to show efficacy. It seems clear now that the existing data obtained in preclinical research have depicted an incomplete picture of stroke pathophysiology. In order to ameliorate bench-to-bed translation, in this review we first describe the main actors on stroke inflammatory and immune responses based on the available preclinical data, highlighting the fact that the link between leukocyte infiltration, lesion volume and neurological outcome remains unclear. We then describe what is known on neuroinflammation and immune responses in stroke patients, and summarize the results of the clinical trials on immunomodulatory drugs. In order to understand the gap between clinical trials and preclinical results on stroke, we discuss in detail the experimental results that served as the basis for the summarized clinical trials on immunomodulatory drugs, focusing on (i) experimental stroke models, (ii) the timing and selection of outcome measuring, (iii) alternative entry routes for leukocytes into the ischemic region, and (iv) factors affecting stroke outcome such as gender differences, ageing, comorbidities like hypertension and diabetes, obesity, tobacco, alcohol consumption and previous infections like Covid-19. We can do better for stroke treatment, especially when targeting inflammation following stroke. We need to re-think the design of stroke experimental setups, notably by (i) using clinically relevant models of stroke, (ii) including both radiological and neurological outcomes, (iii) performing long-term follow-up studies, (iv) conducting large-scale preclinical stroke trials, and (v) including stroke comorbidities in preclinical research.

Nutritional risk markers among stroke out-patients at the neurology clinic of a teaching hospital in Ghana

Introduction

stroke survivors are at risk of malnutrition due to inadequate dietary intake, as a result of neurological disorders causing dysphagia, depression and impaired ability to self-feed. There is paucity of information on nutritional status of stroke survivors after discharge from hospital care, hence, this study sought to determine the nutritional risk markers among stroke out-patients at the Neurology Clinic of Komfo Anokye Teaching Hospital, Kumasi, Ghana.

Methods

a cross-sectional study was conducted among 106 stroke survivors at Komfo Anokye Teaching Hospital, Kumasi, Ghana. Nutritional status of stroke survivors was assessed, using body mass index (BMI) and mid upper arm circumference (MUAC). Biochemical and haematological nutrition indicators including total serum protein, serum albumin, total lymphocyte count, uric acid and haemoglobin were also determined. Independent t-test and ANOVA were used to test differences between mean values.

Results

the mean age of study participants was 58.47±14.2 years, with 56% being females. Overall, 96 (88.7%) of the participants had malnutrition, of whom 66 (68.8%) were undernourished, while 30 (31.2%) had overnutrition. It was also found that 38.7% of the participants were anaemic, based on haemoglobin levels. Using mean BMI, stroke survivors who had been discharged over five years were significantly overweight (p = 0.010).

Conclusion

there was high level of malnutrition among stroke out-patients in this study. The most common nutrition-related problem in the stroke survivors studied was anaemia. Findings from this study suggest the need for nutrition intervention strategies to address the high burden of malnutrition among the stroke survivors.

The Role of Resolvins: EPA and DHA Derivatives Can Be Useful in the Prevention and Treatment of Ischemic Stroke

INTRODUCTION

Most ischemic strokes develop as a result of atherosclerosis, in which inflammation plays a key role. The synthesis cascade of proinflammatory mediators participates in the process induced in the vascular endothelium and platelets. Resolvins are anti-inflammatory mediators originating from eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which may improve the prognosis related to atherosclerosis by inhibiting the production of proinflammatory cytokines, limiting neutrophil migration, or positively influencing phagocytosis. Although clinical trials with resolvin in humans after stroke have not been realized, they may soon find application.

AIM

The aim of the study was to review the available literature on the scope of the possibilities of the prevention and treatment of stroke with the use of resolvins, EPA and DHA derivatives.

MATERIALS AND METHODS

The review features articles published until 31 January 2020. The search for adequate literature was conducted using the keywords: stroke and resolvins. Over 150 articles were found. Studies not written in English, letters to the editor, conference abstracts, and duplicate information were excluded.

RESULTS

In several studies using the animal model, the supplementation of resolvin D2 decreased brain damage caused by myocardial infarction, and it reversed the neurological dysfunction of the brain. A decrease in the concentration of proinflammatory cytokines, such as TNF-α, Il-6, and Il-1β, was also observed, as well as a decrease in the scope of brain damage. In the context of stroke in animals, the treatment with resolvin D2 (RvD2) (injection) has a better effect than supplementation with DHA.

CONCLUSIONS

Resolvins are characterised by strong anti-inflammatory properties. Resolvins improve prognosis and decrease the risk of developing cardiovascular disease, consequently lowering the risk of stroke, and may find application in the treatment of stroke.

Regulation of Glycemia in the Recovery Phase After Stroke Counteracts the Detrimental Effect of Obesity-Induced Type 2 Diabetes on Neurological Recovery

The interplay between obesity and type 2 diabetes (T2D) in poststroke recovery is unclear. Moreover, the impact of glucose control during the chronic phase after stroke is undetermined. We investigated whether obesity-induced T2D impairs neurological recovery after stroke by using a clinically relevant experimental design. We also investigated the potential efficacy of two clinically used T2D drugs: the dipeptidyl peptidase 4 inhibitor linagliptin and the sulfonylurea glimepiride. We induced transient middle cerebral artery occlusion (tMCAO) in T2D/obese mice (after 7 months of high-fat diet [HFD]) and age-matched controls. After stroke, we replaced HFD with standard diet for 8 weeks to mimic the poststroke clinical situation. Linagliptin or glimepiride were administered daily from 3 days after tMCAO for 8 weeks. We assessed neurological recovery weekly by upper-limb grip strength. Brain damage, neuroinflammation, stroke-induced neurogenesis, and atrophy of parvalbumin-positive (PV⁺) interneurons were quantified by immunohistochemistry. T2D/obesity impaired poststroke neurological recovery in association with hyperglycemia, neuroinflammation, and atrophy of PV⁺ interneurons. Both drugs counteracted these effects. In nondiabetic mice, only linagliptin accelerated recovery. These findings shed light on the interplay between obesity and T2D in stroke recovery. Moreover, they promote the use of rehabilitative strategies that are based on efficacious glycemia regulation, even if initiated days after stroke.

High fat diet accelerates and exacerbates microgliosis and neuronal damage/death in the somatosensory cortex after transient forebrain ischemia in gerbils

Obesity has been known as an independent risk factor for stroke. Effects of high-fat diet (HFD)-induced obesity on neuronal damage in the somatosensory cortex of animal models of cerebral ischemia have not been studied yet. In this study, HFD-induced obesity was used to study the impact of obesity on neuronal damage/loss and microgliosis in the somatosensory cortex of a gerbil model of 5-min transient forebrain ischemia. We used gerbils fed normal diet (ND) and HFD and chronologically examined microgliosis (microglial cell activation) by ionized calcium-binding adapter molecule 1 (Iba-1) immunohistochemistry. In addition, we examined neuronal damage or death by using neuronal nuclear protein (NeuN, a neuronal marker) immunohistochemistry and Fluoro-Jade B (F-J B, a marker for neuronal degeneration) histofluorescence staining. We found that ischemia-induced microgliosis in ND-fed gerbils was increased from 2 days post-ischemia; however, ischemia-mediated microgliosis in HFD-fed gerbils increased from 1 day post-ischemia and more accelerated with time than that in the ND-fed gerbils. Ischemia-induced neuronal death/loss in the somatosensory cortex in the ND-fed gerbils was apparently found at 5 days post-ischemia. However, in the HFD-fed gerbils, neuronal death/loss was shown from 2 days post-ischemia and progressively exacerbated at 5 days post-ischemia. Our findings indicate that HFD can evoke earlier microgliosis and more detrimental neuronal death/loss in the somatosensory cortex after transient ischemia than ND evokes.

Obesity Drives Delayed Infarct Expansion, Inflammation, and Distinct Gene Networks in a Mouse Stroke Model

Obesity is associated with chronic peripheral inflammation, is a risk factor for stroke, and causes increased infarct sizes. To characterize how obesity increases infarct size, we fed a high-fat diet to wild-type C57BL/6J mice for either 6 weeks or 15 weeks and then induced distal middle cerebral artery strokes. We found that infarct expansion happened late after stroke. There were no differences in cortical neuroinflammation (astrogliosis, microgliosis, or pro-inflammatory cytokines) either prior to or 10 h after stroke, and also no differences in stroke size at 10 h. However, by 3 days after stroke, animals fed a high-fat diet had a dramatic increase in microgliosis and astrogliosis that was associated with larger strokes and worsened functional recovery. RNA sequencing revealed a dramatic increase in inflammatory genes in the high-fat diet-fed animals 3 days after stroke that were not present prior to stroke. Genetic pathways unique to diet-induced obesity were primarily related to adaptive immunity, extracellular matrix components, cell migration, and vasculogenesis. The late appearance of neuroinflammation and infarct expansion indicates that there may be a therapeutic window between 10 and 36 h after stroke where inflammation and obesity-specific transcriptional programs could be targeted to improve outcomes in people with obesity and stroke.

Combined impact of body mass index and glycemic control on the efficacy of clopidogrel-aspirin therapy in patients with minor stroke or transient ischemic attack

Background: A single index of body mass index (BMI) may not fully address its impact on anti-platelet therapy. We aimed to elucidate the combined impact of BMI and dysglycemia expressed by glycated albumin (GA) on efficacy of clopidogrel-aspirin therapy among minor stroke (MS) or transient ischemic attack (TIA) patients.

Results: Patients with overweight/obesity and low GA levels still benefited from clopidogrel-aspirin therapy for stroke recurrence (Hazard ratio [HR]: 0.48, 95 % confidence interval [CI]: 0.28–0.82), so did those with high GA levels but low/normal weight (HR: 0.67, 95 % CI: 0.45–0.99). However, patients with both overweight/obesity and high GA levels did not benefit from clopidogrel-aspirin therapy (HR: 0.89, 95 % CI: 0.59–1.33).

Conclusions: Compared with aspirin alone, efficacy of clopidogrel-aspirin therapy for stroke still exists in overweight/obesity patients with normal glycemic control.

Methods: In Clopidogrel in High-Risk Patients with Acute Nondisabling Cerebrovascular Events trial, 3044 patients with available baseline GA were recruited. Low/normal weight and overweight/obesity were defined as BMI < 25 kg/m² and ≥ 25 kg/m², respectively. Elevated and low GA levels were defined as GA levels > 15.5 % and ≤ 15.5 %, respectively. The primary outcome was stroke recurrence during the 90-day follow-up.

A high-fat diet rich in corn oil exaggerates the infarct size and memory impairment in rats with cerebral ischemia and is associated with suppressing osteopontin and Akt, and activating GS3Kβ, iNOS, and NF-κB

The increase in osteopontin (OPN) levels after stroke induces neural protection by activating Akt signaling and inhibiting GS3Kβ, iNOS, and NF-κB. This study investigated the effect of a high-fat diet rich in corn oil (CO-HFD) on infarct size and memory function in rats after induction of cerebral ischemia in rats and investigated its effect on the expression of OPN/Akt/iNOS/NF-κB signaling pathways. Rats were initially fed a standard diet (STD, 3.82 kcal/g; 9.4%, from fat) or a CO-HFD (5.4 kcal/g, 40% from fat) for 12 weeks. Then, both groups were further subdivided into either sham group or group exposed to cerebral ischemia by the middle cerebral artery occlusion (MCAO) protocol. Compared with sham-operated rats fed STD diet, neurological scores and both short- and long-term memory functions were significantly impaired in sham-operated CO-HFD-fed rats. In addition, brains collected from CO-HFD-fed rats showed lower protein levels of OPN, p-Akt (Thr³⁰⁸), p-GS3Kβ (Ser⁹), and Bcl-2 and had higher protein levels of iNOS, cleaved caspase-3, nuclear NF-κB p65, and cytoplasmic cytochrome C. However, once exposed to MCAO surgery, similar but more profound alterations of all these biochemical parameters with more severe impairment in short- and long-term memory functions and larger infarct size were noticed in the brains of CO-HFD-fed rats as compared with STD-fed rats exposed to MCAO. In conclusion, chronic consumption of CO-HFD induces memory impairments and worsens memory function recovery and infarct size after cerebral ischemia in rats by reducing levels of OPN, inhibiting the activation of Akt and activating iNOS and NF-κB.

Changes in cerebral perfusion following a 12-month exercise and diet intervention

Overweight and obesity may damage the cerebrovascular architecture, resulting in a significant reduction in cerebral blood flow. To date, there have been few randomized clinical trials (RCT) examining whether obesity-related reductions in cerebral blood flow could be modified by weight loss. Further, it is unknown whether the behavioral intervention strategy for weight loss (i.e., diet alone or diet combined with exercise) differentially influences cerebral blood flow in adults with overweight or obesity. The primary aim of this study was to determine whether a 12-month RCT of exercise and diet increases cerebral blood flow in 125 midlife (Mean age ± SD = 44.63 ± 8.36 years) adults with overweight and obesity. Further, we evaluated whether weight loss via diet combined with aerobic exercise has an added effect on changes in cerebral blood flow compared to weight loss via diet alone and whether there were regionally specific effects of the type of behavioral intervention on cerebral blood flow patterns. Consistent with our predictions, a 12-month diet and exercise program resulting in 10% weight loss increased cerebral blood flow. These effects were widespread and extended throughout frontal, parietal, and subcortical regions. Further, there was some regional specificity of effects for both diet-only and diet combined with exercise. Our results demonstrate that weight-related reductions in cerebral blood flow can be modified by 10% weight loss over the course of 12 months and that interventions involving exercise exposure may provide unique effects on cerebral blood flow compared to interventions involving only diet.

Mendelian Randomization Study of Obesity and Cerebrovascular Disease

OBJECTIVE

To systematically investigate causal relationships between obesity and cerebrovascular disease and the extent to which hypertension and hyperglycemia mediate the effect of obesity on cerebrovascular disease.

METHODS

We used summary statistics from genome-wide association studies for body mass index (BMI), waist-to-hip ratio (WHR), and multiple cerebrovascular disease phenotypes. We explored causal associations with 2-sample Mendelian randomization (MR) accounting for genetic covariation between BMI and WHR, and we assessed what proportion of the association between obesity and cerebrovascular disease was mediated by systolic blood pressure (SBP) and blood glucose levels, respectively.

RESULTS

Genetic predisposition to higher BMI did not increase the risk of cerebrovascular disease. In contrast, for each 10% increase in WHR there was a 75% increase (95% confidence interval [CI] = 44-113%) in risk for large artery ischemic stroke, a 57% (95% CI = 29-91%) increase in risk for small vessel ischemic stroke, a 197% increase (95% CI = 59-457%) in risk of intracerebral hemorrhage, and an increase in white matter hyperintensity volume (β = 0.11, 95% CI = 0.01-0.21). These WHR associations persisted after adjusting for genetic determinants of BMI. Approximately one-tenth of the observed effect of WHR was mediated by SBP for ischemic stroke (proportion mediated: 12%, 95% CI = 4-20%), but no evidence of mediation was found for average blood glucose.

INTERPRETATION

Abdominal adiposity may trigger causal pathological processes, partially independent from blood pressure and totally independent from glucose levels, that lead to cerebrovascular disease. Potential targets of these pathological processes could represent novel therapeutic opportunities for stroke. ANN NEUROL 2020;87:516-524.

Comorbidity and age in the modelling of stroke: are we still failing to consider the characteristics of stroke patients?

Stroke is a significant cause of mortality and morbidity for which there are limited treatment options. Virtually all drug interventions that have been successful preclinically in experimental stroke have failed to translate to an effective treatment in the clinical setting. In this review, we examine one of the factors likely contributing to this lack of translation, the failure of preclinical studies to consider fully the advanced age and comorbidities (eg, hypertension or diabetes) present in most patients with stroke. Age and comorbidities affect the likelihood of suffering a stroke, disease progression and the response to treatment. Analysing data from preclinical systematic reviews of interventions for ischaemic stroke we show that only 11.4% of studies included an aged or comorbid model, with hypertension being the most frequent. The degree of protection (% reduction in infarct volume) varied depending on the comorbidity and the type of intervention. We consider reasons for the lack of attention to comorbid and aged animals in stroke research and discuss the value of testing a potential therapy in models representing a range of comorbidities that affect patients with stroke. These models can help establish any limits to a treatment's efficacy and inform the design of clinical trials in appropriate patient populations.

MMP-12 as a potential biomarker to forecast ischemic stroke in obese patients

Human health is threatened by obesity which causes the increasing incidence of various diseases, especially stroke. Ischemic stroke (IS) is mostly caused by the rupture of arterial plaque, whose instability is positively associated with matrix metalloproteinases (MMPs) that degrades extracellular matrix components. Studies have shown that matrix metalloproteinase-12 (MMP-12) may be involved in the pathogenesis of IS. Because of the higher incidence of stroke in obese patients than that in normal weight people, it is urgent for obesity to forecast stroke early. Considering high levels MMP-12 in obesity, we put forward that MMP-12 may be a potential biomarker for IS in obese patients.

Stroke Induces Prolonged Changes in Lipid Metabolism, the Liver and Body Composition in Mice

During recovery, stroke patients are at risk of developing long-term complications that impact quality of life, including changes in body weight and composition, depression and anxiety, as well as an increased risk of subsequent vascular events. The aetiologies and time-course of these post-stroke complications have not been extensively studied and are poorly understood. Therefore, we assessed long-term changes in body composition, metabolic markers and behaviour after middle cerebral artery occlusion in mice. These outcomes were also studied in the context of obesity, a common stroke co-morbidity proposed to protect against post-stroke weight loss in patients. We found that stroke induced long-term changes in body composition, characterised by a sustained loss of fat mass with a recovery of lean weight loss. These global changes in response to stroke were accompanied by an altered lipid profile (increased plasma free fatty acids and triglycerides) and increased adipokine release at 60 days. After stroke, the liver also showed histological changes indicative of liver damage and a decrease in plasma alanine aminotransferase (ALT) was observed. Stroke induced depression and anxiety-like behaviours in mice, illustrated by deficits in exploration, nest building and burrowing behaviours. When initial infarct volumes were matched between mice with and without comorbid obesity, these outcomes were not drastically altered. Overall, we found that stroke induced long-term changes in depressive/anxiety-like behaviours, and changes in plasma lipids, adipokines and the liver that may impact negatively on future vascular health.

A 2-Min Transient Ischemia Confers Cerebral Ischemic Tolerance in Non-Obese Gerbils, but Results in Neuronal Death in Obese Gerbils by Increasing Abnormal mTOR Activation-Mediated Oxidative Stress and Neuroinflammation

A brief episode of transient ischemia (TI) can confer cerebral ischemic tolerance against a subsequent severer TI under standard condition. The brain under obesity’s conditions is more sensitive to ischemic injury. However, the impact of a brief episode of TI under obesity’s conditions has not been fully addressed yet. Thus, the objective of this study was to determine the effect of a brief TI in the hippocampus of high-fat diet (HFD)-induced obese gerbils and related mechanisms. Gerbils were maintained on HFD or normal diet (ND) for 12 weeks and subjected to 2 min TI. HFD gerbils were heavier, with higher blood glucose, serum total cholesterol, triglycerides, and leptin levels. Massive loss of pyramidal neurons occurred in the hippocampal cornu ammonis 1 (CA1) field of HFD animals at 5 days after 2 min of TI, but 2 min of TI did not elicit death of pyramidal neurons in ND gerbils. The HFD group showed significantly increased levels of oxidative stress indicators (dihydroethidium and 4-hydroxynonenal) and proinflammatory cytokines (tumor necrosis factor-α and interleukin-1β) and microglial activation in pre- and/or post-ischemic phases compared to the ND group. Levels of mammalian target of rapamycin (mTOR) and phosphorylated-mTOR in the CA1 field of the HFD group were also significantly higher than the ND group. On the other hand, inhibition of mTOR activation by rapamycin (an allosteric mTOR inhibitor) significantly attenuated neuronal death induced by HFD, showing reduction of HFD-induced increases of oxidative stress indicators and proinflammatory cytokines, and microglia activation. Taken together, a brief episode of TI can evoke neuronal death under obesity’s conditions. It might be closely associated with an abnormal increase of mTOR activation-mediated, severe oxidative stress and neuroinflammation in pre- and/or post-ischemic phases.

Obesity-induced type 2 diabetes impairs neurological recovery after stroke in correlation with decreased neurogenesis and persistent atrophy of parvalbumin-positive interneurons

Type 2 diabetes (T2D) hampers stroke recovery though largely undetermined mechanisms. Few preclinical studies have investigated the effect of genetic/toxin-induced diabetes on long-term stroke recovery. However, the effects of obesity-induced T2D are mostly unknown. We aimed to investigate whether obesity-induced T2D worsens long-term stroke recovery through the impairment of brain's self-repair mechanisms - stroke-induced neurogenesis and parvalbumin (PV)+ interneurons-mediated neuroplasticity. To mimic obesity-induced T2D in the middle-age, C57bl/6j mice were fed 12 months with high-fat diet (HFD) and subjected to transient middle cerebral artery occlusion (tMCAO). We evaluated neurological recovery by upper-limb grip strength at 1 and 6 weeks after tMCAO. Gray and white matter damage, stroke-induced neurogenesis, and survival and potential atrophy of PV-interneurons were quantitated by immunohistochemistry (IHC) at 2 and 6 weeks after tMCAO. Obesity/T2D impaired neurological function without exacerbating brain damage. Moreover, obesity/T2D diminished stroke-induced neural stem cell (NSC) proliferation and neuroblast formation in striatum and hippocampus at 2 weeks after tMCAO and abolished stroke-induced neurogenesis in hippocampus at 6 weeks. Finally, stroke resulted in the atrophy of surviving PV-interneurons 2 weeks after stroke in both non-diabetic and obese/T2D mice. However, after 6 weeks, this effect selectively persisted in obese/T2D mice. We show in a preclinical setting of clinical relevance that obesity/T2D impairs neurological functions in the stroke recovery phase in correlation with reduced neurogenesis and persistent atrophy of PV-interneurons, suggesting impaired neuroplasticity. These findings shed light on the mechanisms behind impaired stroke recovery in T2D and could facilitate the development of new stroke rehabilitative strategies for obese/T2D patients.

Acute high-fat feeding leads to disruptions in glucose homeostasis and worsens stroke outcome

Chronic consumption of diets high in fat leads to obesity and can negatively affect brain function. Rodents made obese by long-term maintenance on a high-fat diet have worse outcome after experimental stroke. High-fat consumption for only three days does not induce obesity but has rapid effects on the brain including memory impairment. However, the effect of brief periods of high-fat feeding or high-fat consumption in the absence of obesity on stroke is unknown. We therefore tested the effect of an acute period of high-fat feeding (three days) in C57B/6 mice on outcome after middle cerebral artery occlusion (MCAo). In contrast to a chronic high-fat diet (7.5 months), an acute high-fat diet had no effect on body weight, adipose tissue, lipid profile or inflammatory markers (in periphery and the brain). Three days of high-fat feeding impaired glucose tolerance, increased plasma glucose and insulin and brain expression of the glucose transporter GLUT-1. Ischaemic damage was increased (48%) in mice fed an acute high-fat diet, and was associated with a further reduction in GLUT-1 in the ischaemic hemisphere. These data demonstrate that only a brief period of high-fat consumption has a negative effect on glucose homeostasis and worsens outcome after ischaemic stroke.

Obesity Paradox in Ischemic Stroke: Clinical and Molecular Insights

It has recently emerged the concept of "obesity paradox," a term used to describe the unexpected improved prognosis and lower mortality rates found in several diseases in patients with higher body weight. Concerning stroke, few clinical studies have assessed this obesity paradox showing contradictory results. Therefore, our aim was to compare clinical evolution and inflammatory balance of obese and non-obese patients after ischemic stroke. We designed a prospective case-control study in patients with acute ischemic stroke categorized into obese (body mass index, BMI ≥ 30 kg/m²) and non-obese (BMI < 30 kg/m²). We compared clinical, anthropometric, radiological, and laboratory variables. The main outcome variable was the functional outcome at 3 months. We included 98 patients (48 non-obese and 50 obese). No differences in functional outcome at 3 months were found (p = 0.882) although a tendency of a greater recovery on neurological impairments was seen in obese subjects. Importantly, obese patients (p = 0.007) and patients who experienced poor outcome (p = 0.006) exhibited a higher reduction in body weight at 3 months after stroke. Moreover, pro-inflammatory IL-6 levels (p = 0.002) were higher in the obese group. However, IL-6 levels decreased over the first week in obese while increased in non-obese. On the contrary, levels of the anti-inflammatory IL-10 rose over the first week in obese patients, whereas remained stable in non-obese. In summary, despite exhibiting several factors associated with poor outcome, obese patients do not evolve worse than non-obese after ischemic stroke. Obesity may counterbalance the inflammatory reaction through an anti-inflammatory stream enhanced in the first moments of stroke.

Biodistribution of Glial Progenitors in a Three Dimensional-Printed Model of the Piglet Cerebral Ventricular System

White matter damage persists in hypoxic-ischemic newborns even when treated with hypothermia. We have previously shown that intraventricular delivery of human glial progenitors (GPs) at the neonatal stage is capable of replacing abnormal host glia and rescuing the lifespan of dysmyelinated mice. However, such transplantation in the human brain poses significant challenges as related to high-volume ventricles and long cell migration distances. These challenges can only be studied in large animal model systems. In this study, we developed a three dimensional (3D)-printed model of the ventricular system sized to a newborn pig to investigate the parameters that can maximize a global biodistribution of injected GPs within the ventricular system, while minimizing outflow to the subarachnoid space. Bioluminescent imaging and magnetic resonance imaging were used to image the biodistribution of luciferase-transduced GPs in simple fluid containers and a custom-designed, 3D-printed model of the piglet ventricular system. Seven independent variables were investigated. The results demonstrated that a low volume (0.1 mL) of cell suspension is essential to keep cells within the ventricular system. If higher volumes (1 mL) are needed, a very slow infusion speed (0.01 mL/min) is necessary. Real-time magnetic resonance imaging demonstrated that superparamagnetic iron oxide (SPIO) labeling significantly alters the rheological properties of the GP suspension, such that, even at high speeds and high volumes, the outflow to the subarachnoid space is reduced. Several other factors, including GP species (human vs. mouse), type of catheter tip (end hole vs. side hole), catheter length (0.3 vs. 7.62 m), and cell concentration, had less effect on the overall distribution of GPs. We conclude that the use of a 3D-printed phantom model represents a robust, reproducible, and cost-saving alternative to in vivo large animal studies for determining optimal injection parameters.

Analysis of Influencing Factors of Poststroke Depression: Is Higher Body Mass Index Always a Risk Factor of Poststroke Depression?

Poststroke depression (PSD) is a common complication of stroke. We sought to investigate the influencing factors of PSD and explored the association between body mass index (BMI) and PSD. A total of 397 stroke patients in a hospital in Qiqihar City, China, were included in this study in 2016. The order of independent variable importance was the score of the National Institute of Health Stroke Scale, frequency of stroke, age, BMI, and sleep duration. Sleep duration of 7 hours or more (compared with <7 hours) was negatively associated with the Self-Rating Depression Scale (SDS) score in all quantiles. BMI of 28.0 kg/m or more (compared with 24.0-28.0 kg/m) was negatively associated with SDS score, and the coefficients manifested a continuous increasing trend from P30 to P84.1 in patients aged 65 years or more. In addition, the relationship between BMI and SDS score demonstrated a "U"-shaped curve in patients aged less than 65 years. The National Institute of Health Stroke Scale score, the frequency of stroke, sleep duration, and BMI were the influencing factors of PSD. BMI played different roles in the two age groups.

Stroke: The past, present and future

Since the inception of the British Neuroscience Association, there have been major advances in our knowledge of the mechanistic basis for stroke-induced brain damage. Identification of the ischaemic cascade led to the development of hundreds of new drugs, many showing efficacy in preclinical (animal-based) studies. None of these drugs has yet translated to a successful stroke treatment, current therapy being limited to thrombolysis/thrombectomy. However, this translational failure has led to significant improvements in the quality of animal-based stroke research, with the refinement of rodent models, introduction of new technologies (e.g. transgenics, in vivo brain imaging) and improvements in study design (e.g. STAIR, ARRIVE and IMPROVE guidelines). This has run in parallel with advances in clinical diagnostic imaging for detection of ischaemic versus haemorrhagic stroke, differentiating penumbra from ischaemic core, and improved clinical trial design. These preclinical and clinical advances represent the foundation for successful translation from the bench to the bedside in the near future.

Kejadian Obesitas, Obesitas Sentral, dan Kelebihan Lemak Viseral pada Lansia Wanita

Background: Obesity, central obesity, and visceral fat is an excessive fat that can release various types of diseases such as cardiovascular disease, stroke and can increase the risk of bone damage in the elderly. Objectives: The purpose of this study was to analyze the risk factors of obesity, central obesity, and visceral fat in elderly women. Methods:This was an observational analytic study with cross sectional design. The samples of the study were 81 elderly women registered as member of Posyandu Lansia in the working area of Puskesmas Jagir, Wonokromo, Surabaya. The data collected using 3 times 24-hour food recall, anthropometry (body weight, body height, and waist circumference), visceral fat using Bio Impedance Analysis (BIA), and questionnaire related to subject’s characteristic. The data were analyzed using logistic regression analysis. Results: The results showed that the mean age of the subjects were 67.12±5.97 years old. Most of the subjects have low education (71.6%) and 87.7% of subjects didn’t work. The mean value of daily energy intake was 1074.31±298.67 kcal.  There were 34.6% obese subjects, only 17.3% subjects didn’t experience central obesity, and 28.4% of subjects had excess body visceral fat. The statistical test showed significant correlation between age with obesi (p-value=0.042), age with central obesity (p-value=0.009) but age with visceral fat had no significant correlation (p-value=0.163). Daily food intake, education, and occupation did not show significant correlation with obesity, central obesity, or visceral fat (p-value>0.05).  Conclusions: The risk for obesity and central obesity was decreased with aging in elderly but not with visceral fat.ABSTRAKLatar Belakang: Obesitas, obesitas sentral, dan lemak viseral merupakan penumpukan lemak tubuh yang berlebihan dan berisiko untuk menimbulkan berbagai penyakit degeneratif seperti jantung iskemi dan stroke serta dapat meningkatkan risiko kerusakan tulang pada lansia.  Tujuan: Tujuan dari penelitian ini adalah untuk menganalisis faktor risiko obesitas, obesitas sentral, dan kelebihan lemak viseral pada lansia wanita.Metode: Penelitian ini menggunakan desain studi cross sectional dengan pendekatan kuantitatif.  Sampel dari penelitian ini adalah 81 lansia wanita yang menjadi anggota posyandu lansia di wilayah kerja Puskesmas Jagir, Wonokromo, Surabaya. Pengumpulan data menggunakan food recall 3 x 24 jam, antropometri (berat badan, tinggi badan, dan lingkar perut), lemak viseral menggunakan Bio Impedance Analysis (BIA), serta kuesioner terkait data diri subjek. Data dianalisis dengan menggunakan analisis regresi logistik.Hasil: Hasil penelitian menujukkan rata-rata usia subjek adalah 67,12±5,97. Sebagian besar subjek memiliki riwayat pendidikan rendah (71,6%) dan sebanyak 87,7% subjek tidak bekerja. Rata-rata asupan zat gizi subjek lebih rendah jika dibandingkan dengan Angka Kecukupan Gizi (AKG). Sebanyak 34,6% subjek mengalami obesitas; angka kejadian obesitas sentral yaitu 17,3%; dan 28,4% subjek memiliki lemak viseral tubuh berlebih. Uji statistik menunjukkan hubungan signifikan antara usia dengan obesitas (p-value = 0,042), usia dengan obesitas sentral (p-value = 0,009) tetapi usia dengan lemak viseral tidak memiliki hubungan signifikan (p-value = 0,163). Asupan makanan harian, pendidikan, dan pekerjaan tidak  menunjukkan hubungan signifikan dengan obesitas, obesitas sentral, maupun lemak viseral (p-value > 0,05).Kesimpulan: Pada lansia, risiko mengalami obesitas maupun obesitas sentral semakin menurun seiring dengan bertambahnya usia. Lemak viseral tidak berhubungan dengan usia.

Insulin resistance and clinical outcomes after acute ischemic stroke

Objective

In this study, we aimed to determine whether insulin resistance is associated with clinical outcomes after acute ischemic stroke.

Methods

We enrolled 4,655 patients with acute ischemic stroke (aged 70.3 ± 12.5 years, 63.5% men) who had been independent before admission; were hospitalized in 7 stroke centers in Fukuoka, Japan, from April 2009 to March 2015; and received no insulin therapy during hospitalization. The homeostasis model assessment of insulin resistance (HOMA-IR) score was calculated using fasting blood glucose and insulin levels measured 8.3 ± 7.8 days after onset. Study outcomes were neurologic improvement (≥4-point decrease in NIH Stroke Scale score or 0 at discharge), poor functional outcome (modified Rankin Scale score of ≥3 at 3 months), and 3-month prognosis (stroke recurrence and all-cause mortality). Logistic regression analysis was used to evaluate the association of the HOMA-IR score with clinical outcomes.

Results

The HOMA-IR score was associated with neurologic improvement (odds ratio, 0.68 [95% confidence interval, 0.56–0.83], top vs bottom quintile) and with poor functional outcome (2.02 [1.52–2.68], top vs bottom quintile) after adjusting for potential confounding factors, including diabetes and body mass index. HOMA-IR was not associated with stroke recurrence or mortality within 3 months of onset. The associations were maintained in nondiabetic or nonobese patients. No heterogeneity was observed according to age, sex, stroke subtype, or stroke severity.

Conclusions

These findings suggest that insulin resistance is independently associated with poor functional outcome after acute ischemic stroke apart from the risk of short-term stroke recurrence or mortality.

Risk association, linkage disequilibrium and haplotype analyses of FASN rs4246445, rs2229425, rs2228305 and rs2229422 polymorphisms in overweight and obesity

Introduction: Obesity is commonly linked up with several life-threatening diseases. This study aims to investigate the association of fatty acid synthase (FASN) rs4246445, rs2229425, rs2228305, and rs2229422 single nucleotide polymorphisms (SNPs) with the risk of overweight and obesity in the Malaysian population. Methods: Blood samples were collected from 1030 individuals who were grouped into normal, overweight, and obese categories. Blood biochemistry test and lipid profiling were performed and genomic DNA was extracted. Genotyping was performed using hydrolysis probes and odd ratio with 95% CI was calculated for risk association analysis. Linkage disequilibrium and haplotypes analyses were carried out using SHEsis software. Results: We found that the hemoglobin and white blood cell counts were significantly high in the obese subjects. There is a lack of evidence to link the FASN SNPs with the risk of overweight and obesity in the population. All 4 SNPs were seemed to be in linkage equilibrium. Five common haplotypes were identified in this study but none of them was significantly associated with overweight and obesity in the population. Conclusion: Our findings suggest a lack of evidence to associate the FASN rs4246445, rs2229425, rs2228305, and rs2229422 SNPs with the risk of overweight and obesity in the Malaysian population. All 4 SNPs were independent of each other and not all identified haplotypes were significantly associated with overweight and obesity in this study.

Cellular and Molecular Mechanisms Underlying Non-Pharmaceutical Ischemic Stroke Therapy in Aged Subjects

The incidence of ischemic stroke in humans increases exponentially above 70 years both in men and women. Comorbidities like diabetes, arterial hypertension or co-morbidity factors such as hypercholesterolemia, obesity and body fat distribution as well as fat-rich diet and physical inactivity are common in elderly persons and are associated with higher risk of stroke, increased mortality and disability. Obesity could represent a state of chronic inflammation that can be prevented to some extent by non-pharmaceutical interventions such as calorie restriction and hypothermia. Indeed, recent results suggest that H₂S-induced hypothermia in aged, overweight rats could have a higher probability of success in treating stroke as compared to other monotherapies, by reducing post-stroke brain inflammation. Likewise, it was recently reported that weight reduction prior to stroke, in aged, overweight rats induced by caloric restriction, led to an early re-gain of weight and a significant improvement in recovery of complex sensorimotor skills, cutaneous sensitivity, or spatial memory.

CONCLUSION

animal models of stroke done in young animals ignore age-associated comorbidities and may explain, at least in part, the unsuccessful bench-to-bedside translation of neuroprotective strategies for ischemic stroke in aged subjects.