Oral ascorbic acid 2-glucoside prevents coordination disorder induced via laser-induced shock waves in rat brain

A theoretical study on radical scavenging activity of phenolic derivatives naturally found within Alternaria alternata extract

The increasing oxidative stress demands potential chemical compounds derived from natural resources with good antioxidant activity to overcome adverse health issues. In this context, we investigated the antioxidant properties of four dibenzopyrone phenolic compounds obtained from the endophytic fungus Alternaria alternata: altenusin, altenusin B, alterlactone, and dehydroaltenusin using DFT calculations. Our investigation focused on understanding the structure-antioxidant property relationship. It delved into probing the activity by modelling the antioxidant mechanisms. The computed transition states and thermochemical parameters, along with the structural attributes, indicate that altenusin B has good antioxidant efficacy among the four compounds, and it follows the HAT mechanism in an aqueous phase. Remarkably, our findings indicate that altenusin B exhibits potent HOO˙ radical scavenging properties, characterized by the computed high rate constant. The molecular docking studies of these compounds with the pro-oxidant enzyme xanthine oxidase (XO) gave insights into the binding modes of the compounds in the protein environment. Furthermore, molecular dynamics (MD) simulations were employed to study the interaction and stability of the compounds inside the XO enzyme. Our exploration sheds light on the radical scavenging potential of the -OH sites and the underlying antioxidant mechanisms that underpin the compounds' effective antioxidant potential.

Visceral hypersensitivity induced by mild traumatic brain injury via the corticotropin-releasing hormone receptor: An animal model

BACKGROUND

Mild blast-induced traumatic brain injury (bTBI) induces various gut symptoms resembling human irritable bowel syndrome (IBS) as one of mental and behavioral disorders. However, the underlying mechanisms remain unclear. We investigated whether the extremely localized brain impact extracranially induced by laser-induced shock wave (LISW) evoked IBS-like phenomenon including visceral hypersensitivity and intestinal hyperpermeability in rats.

METHODS

The rats were subjected to LISW on the scalp to shock the entire brain. Visceral hypersensitivity was evaluated by the threshold pressure of abdominal withdrawal reflex (AWR) using a colorectal distension test. Permeability was evaluated by the concentration of penetrating FITC-dextran from intestine and the mRNA expression levels of tight junction family proteins. Involvement of corticotropin-releasing factor receptor (CRFR) 1 and 2 was examined by evaluating mRNA expression and modulating CRFR function with agonist, recombinant CRF (10 μg/kg), and antagonist, astressin (33 μg/kg). High-throughput sequencing of the gut microbiota was performed by MiSeqIII instrument and QIIME tool.

KEY RESULTS

The thresholds of the AWR were significantly lowered after LISW. Permeability was increased in small intestine by LISW along with decreased expression of tight junction ZO-1. LISW significantly increased CRFR1 expression and decreased CRFR2 expression. Visceral hypersensitivity was significantly aggravated by CRFR agonist and suppressed by CRFR antagonist. The α- and β-diversity of the fecal microbiota was altered after LISW.

CONCLUSIONS AND INFERENCES

LISW provoked visceral hypersensitivity, small intestinal hyperpermeability, altered expression of CRFRs and changes in the microbiota, suggesting that genuine bTBI caused by LISW can induce a pathophysiology comparable to that of human IBS.

The effect of Vitamins C and E on clinical outcomes of patients with severe traumatic brain injury: A propensity score matching study

Background

The aim of this study was to assess the effect of Vitamins C and E on mortality, intensive care unit (ICU) length of stay, and Glasgow Outcome Scale-Extended (GOS-E) score of traumatic brain injury (TBI) patients.

Methods

Using data from records of patients in a retrospective cohort study, we included 1321 TBI patients, 269 treated and 1052 untreated, aged over 18 years with information on exposure (i.e., Vitamins C and E) and confounders. Age, Glasgow Coma Scale, pupil status, Rotterdam classification, blood sugar, blood pressure, international normalized ratio, and comorbidity of patients were considered as the confounding factors. Endpoints were GOS-E on follow-up, mortality, and ICU length of stay. Propensity score matching was performed to adjust the confounders.

Results

Based on the average treatment effect estimates, the use of Vitamins C and E reduced the risk of mortality (risk difference [RD]: -0.07; 95% confidence interval [CI]: -0.14--0.003) and reduced the length of ICU stay (RD -1.77 95% CI:-3.71-0.16). Furthermore, our results showed that GOS-E was improved significantly (RD: 0.09, 95% CI : 0.03-0.16).

Conclusion

Our study suggests that using Vitamins C and E could decrease mortality and length of ICU stay and improve the GOS-E score and functions of the patients with severe TBI. As they are safe and inexpensive medications, they can be used in routine practice in ICUs to improve the outcomes of TBI patients.

Neuro-Inflammation Modulation and Post-Traumatic Brain Injury Lesions: From Bench to Bed-Side

Head trauma is the most common cause of disability in young adults. Known as a silent epidemic, it can cause a mosaic of symptoms, whether neurological (sensory-motor deficits), psychiatric (depressive and anxiety symptoms), or somatic (vertigo, tinnitus, phosphenes). Furthermore, cranial trauma (CT) in children presents several particularities in terms of epidemiology, mechanism, and physiopathology-notably linked to the attack of an immature organ. As in adults, head trauma in children can have lifelong repercussions and can cause social and family isolation, difficulties at school, and, later, socio-professional adversity. Improving management of the pre-hospital and rehabilitation course of these patients reduces secondary morbidity and mortality, but often not without long-term disability. One hypothesized contributor to this process is chronic neuroinflammation, which could accompany primary lesions and facilitate their development into tertiary lesions. Neuroinflammation is a complex process involving different actors such as glial cells (astrocytes, microglia, oligodendrocytes), the permeability of the blood-brain barrier, excitotoxicity, production of oxygen derivatives, cytokine release, tissue damage, and neuronal death. Several studies have investigated the effect of various treatments on the neuroinflammatory response in traumatic brain injury in vitro and in animal and human models. The aim of this review is to examine the various anti-inflammatory therapies that have been implemented.

Ascorbic acid 2-glucoside preconditioning enhances the ability of bone marrow mesenchymal stem cells in promoting wound healing

Background

Nowadays, wound is associated with a complicated repairing process and still represents a significant biomedical burden worldwide. Bone marrow mesenchymal stem cells (BMSCs) possess multidirectional differentiation potential and secretory function, emerging as potential cellular candidates in treating wounds. Ascorbic acid 2-glucoside (AA2G) is a well-known antioxidant and its function in BMSC-promoting wound healing is worth exploring.

Methods

The in vitro cell proliferation, migration, and angiogenesis of BMSCs and AA2G-treated BMSCs were detected by flow cytometry, EDU staining, scratch assay, transwell assay, and immunofluorescence (IF). Besides, the collagen formation effect of AA2G-treated BMSCs conditioned medium (CM) on NIH-3T3 cells was evaluated by hydroxyproline, qRT-PCR and IF staining detection. Next, in the wound healing mouse model, the histological evaluation of wound tissue in PBS, BMSCs, and AA2G-treated BMSCs group were further investigated. Lastly, western blot and ELISA were used to detect the expression levels of 5-hmc, TET2 and VEGF protein, and PI3K/AKT pathway activation in BMSCs treated with or without AA2G.

Results

The in vitro results indicated that AA2G-treated BMSCs exhibited stronger proliferation and improved the angiogenesis ability of vascular endothelial cells. In addition, the AA2G-treated BMSCs CM enhanced migration and collagen formation of NIH-3T3 cells. In vivo, the AA2G-treated BMSCs group had a faster wound healing rate and a higher degree of vascularization in the new wound, compared with the PBS and BMSCs group. Moreover, AA2G preconditioning might enhance the demethylation process of BMSCs by regulating TET2 and up-regulating VEGF expression by activating the PI3K/AKT pathway.

Conclusions

AA2G-treated BMSCs promoted wound healing by promoting angiogenesis and collagen deposition, thereby providing a feasible strategy to reinforce the biofunctionability of BMSCs in treating wounds.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-022-02797-0.

Neuroprotective Properties of Vitamin C: A Scoping Review of Pre-Clinical and Clinical Studies

There is a need for novel neuroprotective therapies. We aimed to review the evidence for exogenous vitamin C as a neuroprotective agent. MEDLINE, Embase, and Cochrane library databases were searched from inception to May 2020. Pre-clinical and clinical reports evaluating vitamin C for acute neurological injury were included. Twenty-two pre-clinical and 11 clinical studies were eligible for inclusion. Pre-clinical studies included models of traumatic and hypoxic brain injury, subarachnoid and intracerebral hemorrhage, and ischemic stroke. The median [IQR] maximum daily dose of vitamin C in animal studies was 120 [50-500] mg/kg. Twenty-one animal studies reported improvements in biomarkers, functional outcome, or both. Clinical studies included single reports in neonatal hypoxic encephalopathy, traumatic brain injury, and subarachnoid hemorrhage and eight studies in ischemic stroke. The median maximum daily dose of vitamin C was 750 [500-1000] mg, or ∼10 mg/kg for an average-size adult male. Apart from one case series of intracisternal vitamin C administration in subarachnoid hemorrhage, clinical studies reported no patient-centered benefit. Although pre-clinical trials suggest that exogenous vitamin C improves biomarkers of neuroprotection, functional outcome, and mortality, these results have not translated to humans. However, clinical trials used approximately one tenth of the vitamin C dose of animal studies.

Behavioral and Histopathological Impairments Caused by Topical Exposure of the Rat Brain to Mild-Impulse Laser-Induced Shock Waves: Impulse Dependency

Although an enormous number of animal studies on blast-induced traumatic brain injury (bTBI) have been conducted, there still remain many uncertain issues in its neuropathology and mechanisms. This is partially due to the complex and hence difficult experimental environment settings, e.g., to minimize the effects of blast winds (tertiary mechanism) and to separate the effects of brain exposure and torso exposure. Since a laser-induced shock wave (LISW) is free from dynamic pressure and its energy is spatially well confined, the effects of pure shock wave exposure (primary mechanism) solely on the brain can be examined by using an LISW. In this study, we applied a set of four LISWs in the impulse range of 15–71 Pa·s to the rat brain through the intact scalp and skull; the interval between each exposure was ~5 s. For the rats, we conducted locomotor activity, elevated plus maze and forced swimming tests. Axonal injury in the brain was also examined by histological analysis using Bodian silver staining. Only the rats with exposure at higher impulses of 54 and 71 Pa·s showed significantly lower spontaneous movements at 1 and 2 days post-exposure by the locomotor activity test, but after 3 days post-exposure, they had recovered. At 7 days post-exposure, however, these rats (54 and 71 Pa·s) showed significantly higher levels of anxiety-related and depression-like behaviors by the elevated plus maze test and forced swimming test, respectively. To the best of the authors' knowledge, there have been few studies in which a rat model showed both anxiety-related and depression-like behaviors caused by blast or shock wave exposure. At that time point (7 days post-exposure), histological analysis showed significant decreases in axonal density in the cingulum bundle and corpus callosum in impulse-dependent manners; axons in the cingulum bundle were found to be more affected by a shock wave. Correlation analysis showed a statistically significant correlation between the depression like-behavior and axonal density reduction in the cingulum bundle. The results demonstrated the dependence of behavior deficits and axonal injury on the shock wave impulse loaded on the brain.

Axonal damage and behavioral deficits in rats with repetitive exposure of the brain to laser-induced shock waves: Effects of inter-exposure time

Much attention has been given to effects of repeated exposure to a shock wave as a possible factor causing severe higher brain dysfunction and post-traumatic stress disorder (PTSD)-like symptoms in patients with mild to moderate blast-induced traumatic brain injury (bTBI). However, it is unclear how the repeated exposure and the inter-exposure time affect the brain. In this study, we topically applied low-impulse (∼54 Pa·s) laser-induced shock waves (LISWs; peak pressure, ∼75.7 MPa) to the rat brain once or twice with the different inter-exposure times (15 min, 1 h, 3 h, 24 h and 7 days) and examined anxiety-related behavior and motor dysfunction in the rats as well as expression of β-amyloid precursor protein (APP) as an axonal damage marker in the brains of the rats. The averaged APP expression scores for the rat brains doubly-exposed to LISWs with inter-exposure times from 15 min to 24 h were significantly higher than those for rats with a single exposure (P < 0.0001). The rats with double exposure to LISWs showed significantly more frequent anxiety-related behavior (P < 0.05) and poorer motor function (P < 0.01) than those of rats with a single exposure. When the inter-exposure time was extended to 7 days, however, the rats showed no significant differences either in axonal damage score or level of motor dysfunction. The results suggest that the cumulative effects of shock wave-related brain injury can be avoided with an appropriate inter-exposure time. However, clinical bTBI occurs in much more complex environments than those in our model. Further study considering other factors, such as the effects of acceleration, is needed to know the clinically-relevant, necessary inter-exposure time.

Comparison of Vitamin C and Its Derivative Antioxidant Activity: Evaluated by Using Density Functional Theory

Vitamin C (VC) is an essential antioxidant, but its application is limited because of its unstable chemical properties. Hence, a variety of VC derivatives have emerged in practical antioxidant applications. To explore the relationship between the antioxidant properties and the chemical structures of vitamin C and its derivatives, density functional theory (DFT) was used in this work to calculate the reaction enthalpies of the mechanisms related to radical scavenging activity. The structures were optimized at the B3LYP-D3(BJ)/6-31G* level of theory. Single point calculations (SPE) were performed at the PWPB95-D3 (BJ)/def2-QZVPP level. To estimate the solvent effect on antioxidant properties, the SMD (solvation model based on density) method was used. The results showed that in the process of optimizing the chemical structure of vitamin C, the antioxidant capacity of its derivatives decreased slightly in aqueous solvents. In the calculation process, it is also found that in the choice of antioxidant mechanism, these compounds are more inclined to the hydrogen atom transfer (HAT) mechanism, and from the chemical structure point of view, the double bond of the lactone ring is essential for its free radical scavenging activity. In general, it is necessary to continue to optimize the structure of VC to obtain derivatives with better oxidation resistance and more practical value.