Dehydroascorbic acid for the treatment of acute ischemic stroke

Activation and Role of Astrocytes in Ischemic Stroke

Ischemic stroke refers to the disorder of blood supply of local brain tissue caused by various reasons. It has high morbidity and mortality worldwide. Astrocytes are the most abundant glial cells in the central nervous system (CNS). They are responsible for the homeostasis, nutrition, and protection of the CNS and play an essential role in many nervous system diseases’ physiological and pathological processes. After stroke injury, astrocytes are activated and play a protective role through the heterogeneous and gradual changes of their gene expression, morphology, proliferation, and function, that is, reactive astrocytes. However, the position of reactive astrocytes has always been a controversial topic. Many studies have shown that reactive astrocytes are a double-edged sword with both beneficial and harmful effects. It is worth noting that their different spatial and temporal expression determines astrocytes’ various functions. Here, we comprehensively review the different roles and mechanisms of astrocytes after ischemic stroke. In addition, the intracellular mechanism of astrocyte activation has also been involved. More importantly, due to the complex cascade reaction and action mechanism after ischemic stroke, the role of astrocytes is still difficult to define. Still, there is no doubt that astrocytes are one of the critical factors mediating the deterioration or improvement of ischemic stroke.

Vitamin C supplementation promotes mental vitality in healthy young adults: results from a cross-sectional analysis and a randomized, double-blind, placebo-controlled trial

Purpose

We aimed to investigate the link of vitamin C status with vitality and psychological functions in a cross-sectional study, and examine their causal relationship through a randomized controlled trial (RCT).

Methods

We first conducted a population-based cross-sectional investigation of healthy young adults (n = 214, 20–39 years), and analyzed the associations of serum vitamin C concentrations with vitality (fatigue and attention) and mood status (stress, depression, and positive and negative affect) using Pearson’s correlation and multiple linear regression analyses. Next, we performed a double-blind RCT in healthy subjects whose serum vitamin C concentrations were inadequate (< 50 μmol/L). Subjects were randomly allocated to receive 500 mg of vitamin C twice a day for 4 weeks (n = 24) or a placebo (n = 22). We assessed vitality, which included fatigue, attention, work engagement, and self-control resources, and measured mood status, including stress, depression, positive and negative affect, and anxiety. ELISA determined serum brain-derived neurotrophic factor (BDNF), and a Stroop color–word test evaluated attention capacity and processing speed.

Results

In the cross-sectional data, the serum vitamin C concentration was positively associated with the level of attention (r = 0.16, p = 0.02; standardized β = 0.21, p = 0.003), while no significant associations with the levels of fatigue and mood variables being found. In the RCT, compared to the placebo, the vitamin C supplementation significantly increased attention (p = 0.03) and work absorption (p = 0.03) with distinct tendency of improvement on fatigue (p = 0.06) and comprehensive work engagement (p = 0.07). The vitamin C supplementation did not affect mood and serum concentrations of BDNF. However, in the Stroop color–word test, the subjects supplemented with vitamin C showed better performance than those in the placebo group (p = 0.04).

Conclusion

Inadequate vitamin C status is related to a low level of mental vitality. Vitamin C supplementation effectively increased work motivation and attentional focus and contributed to better performance on cognitive tasks requiring sustained attention.

Trial registration number and date of registration

Cross-sectional study: KCT0005074 (cris.nih.go.kr)/1 June, 2020 (retrospectively registered). Intervention study: KCT0004276 (cris.nih.go.kr)/4 September, 2019.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00394-021-02656-3.

New oral liposomal vitamin C formulation: properties and bioavailability

Vitamin C is the exogenous compound necessary for a variety of metabolic processes; therefore, the efficient delivery is critical for the maintenance of body homeostasis. Vitamin C pharmacokinetics and low quantities in processed foodstuff, necessitates its continuous supplementation. In the paper, we present the new liposomal formulation of vitamin C free of harmful organic solvents. The formulation was quantitatively characterized with respect to its chemically composition and nano-structuring. The vitamin C accessibility to cells from the formulation was evaluated using evidence derived from experiments performed on cell cultures. Finally, the enhanced bioavailability of vitamin C from the formulation was demonstrated in the medical experiment.

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.

Current and future perspectives on the treatment of cerebral ischemia

INTRODUCTION

After heart disease and combined forms of cancer, stroke is the leading cause of death in the United States. Currently, tissue-plasminogen activator (tPA) thrombolysis is the only thrombolytic therapy that has been shown to improve patient outcome. Presently, the only antithrombotic drug treatment that has proven effective at improving acute ischemic stroke patient outcome is aspirin administration. Despite these studies, no clinical trials have yet demonstrated a reliably effective pharmacological treatment. Areas covered: We conducted a search of recent drug studies for ischemic stroke on clinicaltrials.gov in addition to a literature search for acute ischemic stroke therapy using PubMed. This review details our findings of recent advancements in the pharmacological treatment of acute ischemic stroke. Expert commentary: We concluded that recent attempts to establish new pharmacological treatment protocols for acute ischemic stroke have had limited success, but many Phase III and Phase IV clinical trials demonstrate promise. Moreover, several studies have demonstrated the efficacy of dual-antiplatelet therapies at reducing risk of secondary stroke. Studies for novel therapeutic targets for neuroprotection have been largely unsuccessful. Some trials had positive results; however, there is much room for improvement and other studies show promise in their preliminary stages.