Urinary NOx, a novel potential biomarker for autism spectrum disorder

Hydrothermally Derived Green Carbon Dots from Broccoli Water Extracts: Decreased Toxicity, Enhanced Free-Radical Scavenging, and Anti-Inflammatory Performance

Biomass carbon dots (CDs) derived from natural plants possess the advantages of low cost, photostability, and excellent biocompatibility, with potential applications in chemical sensing, bioimaging, and nanomedicine. However, the development of biomass CDs with excellent antioxidant activity and good biocompatibility is still a challenge. Herein, we propose a hypothesis for enhancing the antioxidant capacity of biomass CDs based on precursor optimization, extraction solvent, and other conditions with broccoli as the biomass. Compared to broccoli water extracts, broccoli powders, and broccoli organic solvent extracts, CDs derived from broccoli water extracts (BWE-CDs) have outstanding antioxidant properties due to the abundant C═C, carbonyl, and amino groups on their surface. After optimization of the preparation condition, the obtained BWE-CDs exhibit excellent free-radical scavenging activity with an EC₅₀ of 68.2 μg/mL for DPPH^• and 22.4 μg/mL for ABTS^•+. Cytotoxicity and zebrafish embryotoxicity results indicated that BWE-CDs have lower cytotoxicity and better biocompatibility than that of CDs derived from organic solvents. In addition, BWE-CDs effectively scavenged reactive oxygen species (ROS) in A549 cells, 293T cells, and zebrafish, as well as eliminating inflammation in LPS-stimulated zebrafish. Mechanistic studies showed that the anti-inflammatory effect of BWE-CDs was dependent on the direct reaction of CDs with free radicals, the regulation of NO levels, and the upregulation of the expression of SOD and GPX-4. This work indicates that the antioxidant activity of CDs could be enhanced by using solvent extracts of biomass as precursors, and the obtained BWE-CDs exhibit characteristics of greenness, low toxicity, and excellent antioxidant and anti-inflammatory activities, which suggests the potential promising application of BWE-CDs as an antioxidant nanomedicine for inflammatory therapy.

The contribution of an imbalanced redox signalling to neurological and neurodegenerative conditions

Nitric oxide and other redox active molecules such as oxygen free radicals provide essential signalling in diverse neuronal functions, but their excess production and insufficient scavenging induces cytotoxic redox stress which is associated with numerous neurodegenerative and neurological conditions. A further component of redox signalling is mediated by a homeostatic regulation of divalent metal ions, the imbalance of which contributes to neuronal dysfunction. Additional antioxidant molecules such as glutathione and enzymes such as super oxide dismutase are involved in maintaining a physiological redox status within neurons. When cellular processes are perturbed and generation of free radicals overwhelms the antioxidants capacity of the neurons, a resulting redox damage leads to neuronal dysfunction and cell death. Cellular sources for production of redox-active molecules may include NADPH oxidases, mitochondria, cytochrome P450 and nitric oxide (NO)-generating enzymes, such as endothelial, neuronal and inducible NO synthases. Several neurodegenerative and developmental neurological conditions are associated with an imbalanced redox state as a result of neuroinflammatory processes leading to nitrosative and oxidative stress. Ongoing research aims at understanding the causes and consequences of such imbalanced redox homeostasis and its role in neuronal dysfunction.

Saliva nitrite is higher in male children with autism spectrum disorder and positively correlated with serum nitrate

OBJECTIVES

Nitric oxide (NO) plays a vital role in neurological development. As an easily accessible and non-invasive fluid, saliva hasn't been evaluated for nitrite among children with autism spectrum disorder (ASD). This study aims to quantify saliva nitrite and explore its relation with serum NO.

METHODS

Saliva sampling and pretreatment methods were optimized, followed by NO measurement via chemiluminescence for 126 ASD children and 129 normally developing children (ND).

RESULTS

In the ASD group, saliva nitrite was significantly higher than that in the ND, with concentrations of 4.97 ± 3.77 μM and 2.66 ± 2.07 μM (p < 0.0001), respectively. Positive correlation was observed between saliva NO2- and serum NO3- in ASD children, which didn't exist in the ND group. Male children in the ASD group had significantly higher NO than that in boys of the ND group, without significant difference between girls in both groups. Correlation was not found between saliva or serum NO and severity of these ASD children.

DISCUSSION

It is reported for the first time that saliva nitrite was positively correlated with serum nitrate in ASD children, with significantly higher NO only in autistic boys. Non-invasive saliva might serve as a predictor of health status of ASD children.

Urine Nitric Oxide Is Lower in Parents of Autistic Children

Parents raising children with autism spectrum disorder (ASD) usually carry on their daily life under tremendous stress, but limited empirical research has been devoted to this population. It is known that parents' health status directly impacts therapeutic outcome of ASD children. As an important regulator in cardiovascular, nervous and immune systems, nitric oxide (NO) levels haven't been reported in parents of ASD children yet. In this study, we measured urine nitrite and nitrate from 43 ASD parents (ASD-P), and 43 healthy adults in the same range of age (Control) who didn't have any ASD descendants. Comparison between the ASD-P and Control groups showed that NO 2 - , NO 3 - , and NO 2 - / NO 3 - were all significantly lower in the ASD-P group. Analysis on the interaction effect of sex and group indicated that urine NO 3 - of mothers in ASD-P was lower than that in females of the Control group, but no significant difference was observed between males in both groups. It is for the first time that urine nitric oxide metabolites (nitrite, nitrate) levels were precisely reported to differentiate parents of autistic children from other adults without ASD descendants. This phenomenon suggests that parents (especially mothers) of autistic children might have experienced more mental and physical stressors, which led to decreased NO levels during metabolism. Further investigations are necessary to uncover the etiology of low urine NO among parents of autistic children.