Chromatographic and mass spectrometric techniques in studies on oxidative stress in autism

The multifaceted role of mitochondria in autism spectrum disorder

Normal brain functioning relies on high aerobic energy production provided by mitochondria. Failure to supply a sufficient amount of energy, seen in different brain disorders, including autism spectrum disorder (ASD), may have a significant negative impact on brain development and support of different brain functions. Mitochondrial dysfunction, manifested in the abnormal activities of the electron transport chain and impaired energy metabolism, greatly contributes to ASD. The aberrant functioning of this organelle is of such high importance that ASD has been proposed as a mitochondrial disease. It should be noted that aerobic energy production is not the only function of the mitochondria. In particular, these organelles are involved in the regulation of Ca2+ homeostasis, different mechanisms of programmed cell death, autophagy, and reactive oxygen and nitrogen species (ROS and RNS) production. Several syndromes originated from mitochondria-related mutations display ASD phenotype. Abnormalities in Ca2+ handling and ATP production in the brain mitochondria affect synaptic transmission, plasticity, and synaptic development, contributing to ASD. ROS and Ca2+ regulate the activity of the mitochondrial permeability transition pore (mPTP). The prolonged opening of this pore affects the redox state of the mitochondria, impairs oxidative phosphorylation, and activates apoptosis, ultimately leading to cell death. A dysregulation between the enhanced mitochondria-related processes of apoptosis and the inhibited autophagy leads to the accumulation of toxic products in the brains of individuals with ASD. Although many mitochondria-related mechanisms still have to be investigated, and whether they are the cause or consequence of this disorder is still unknown, the accumulating data show that the breakdown of any of the mitochondrial functions may contribute to abnormal brain development leading to ASD. In this review, we discuss the multifaceted role of mitochondria in ASD from the various aspects of neuroscience.

Glucose transporter 1 deficiency, AMP-activated protein kinase activation and immune dysregulation in autism spectrum disorder: Novel biomarker sources for clinical diagnosis

The neurophysiological basis of autism spectrum disorder (ASD) is still uncertain. Nevertheless, studies support the hypotheses that oxidative stress, neuroinflammation, immune dysregulation, and metabolic stress are contributors. In this study, the serum levels of 3-nitrotyrosine (3-NT), hypoxia-inducible factor 1 α (HIF-1 α), heat shock protein 70 (HSP-70), interleukin-17A (IL-17A), IL-35, vitamin D3 (VITD), glucose transporter-1 (GUT1), and AMP-activated protein kinase (AMPK) were estimated in Saudi ASD children versus age-matched neurotypical controls, aiming to investigate whether these parameters have potential roles in the pathophysiologic mechanisms of ASD and hoping to find a reliable marker for early ASD diagnosis. This study included 25 ASD children and 25 typically developing children (3-11 years old). The diagnosis of ASD cases was made based on the Autism Diagnostic Observation Schedule (ADOS) and the Statistical Manual of Mental Disorders (DSM-5). ASD subjects were commonly male and revealed an intelligence quotient (IQ) < 70.The results detected that ASD children have remarkable greater serum levels of nitrosative stress (3-NT), hypoxia (HIF-1 α), inflammatory (HSP-70, IL-17A, and AMPK) biomarkers and lower serum levels of anti-inflammatory (IL-35 and VITD) and metabolic stress (GUT-1) biomarkers versus age-matched controls (P ≤ 0.0001). Pearson's correlation study revealed that 3-NT was positively associated with HIF-1 α and HSP-70. HIF-1 α was also positively correlated with HSP-70. AMPK was positively associated with GUT-1, however, IL-17A was negatively correlated with IL-35 and VITD.Limitation:No specific therapeuticdrugs were administered in this study, and further studies are required to confirm the role of the selected biomarkers in ASD managements.

Conclusion

Changes in concentrations of different biomarkers indicate that they are involved in oxidative stress, metabolic stress, immune dysregulation and ASD pathogenesis. Hence, these parameters can prove to be promising biomarkers as well as therapeutic targets for the timely diagnosis and treatment of ASD patients.

Therapeutic Effects of a Novel Form of Biotin on Propionic Acid-Induced Autistic Features in Rats

Magnesium biotinate (MgB) is a novel biotin complex with superior absorption and anti-inflammatory effects in the brain than D-Biotin. This study aimed to investigate the impact of different doses of MgB on social behavior deficits, learning and memory alteration, and inflammatory markers in propionic acid (PPA)-exposed rats. In this case, 35 Wistar rats (3 weeks old) were distributed into five groups: 1, Control; 2, PPA treated group; 3, PPA+MgBI (10 mg, HED); 4, PPA+MgBII (100 mg, HED); 5, PPA+MgBIII (500 mg, HED). PPA was given subcutaneously at 500 mg/kg/day for five days, followed by MgB for two weeks. PPA-exposed rats showed poor sociability and a high level of anxiety-like behaviors and cognitive impairments (p < 0.001). In a dose-dependent manner, behavioral and learning-memory disorders were significantly improved by MgB supplementation (p < 0.05). PPA decreased both the numbers and the sizes of Purkinje cells in the cerebellum. However, MgB administration increased the sizes and the densities of Purkinje cells. MgB improved the brain and serum Mg, biotin, serotonin, and dopamine concentrations, as well as antioxidant enzymes (CAT, SOD, GPx, and GSH) (p < 0.05). In addition, MgB treatment significantly regulated the neurotoxicity-related cytokines and neurotransmission-related markers. For instance, MgB significantly decreased the expression level of TNF-α, IL-6, IL-17, CCL-3, CCL-5, and CXCL-16 in the brain, compared to the control group (p < 0.05). These data demonstrate that MgB may ameliorate dysfunctions in social behavior, learning and memory and reduce the oxidative stress and inflammation indexes of the brain in a rat model.

Oxidative Stress in Autism Spectrum Disorder-Current Progress of Mechanisms and Biomarkers

Autism spectrum disorder (ASD) is a type of neurodevelopmental disorder that has been diagnosed in an increasing number of children around the world. Existing data suggest that early diagnosis and intervention can improve ASD outcomes. However, the causes of ASD remain complex and unclear, and there are currently no clinical biomarkers for autism spectrum disorder. More mechanisms and biomarkers of autism have been found with the development of advanced technology such as mass spectrometry. Many recent studies have found a link between ASD and elevated oxidative stress, which may play a role in its development. ASD is caused by oxidative stress in several ways, including protein post-translational changes (e.g., carbonylation), abnormal metabolism (e.g., lipid peroxidation), and toxic buildup [e.g., reactive oxygen species (ROS)]. To detect elevated oxidative stress in ASD, various biomarkers have been developed and employed. This article summarizes recent studies about the mechanisms and biomarkers of oxidative stress. Potential biomarkers identified in this study could be used for early diagnosis and evaluation of ASD intervention, as well as to inform and target ASD pharmacological or nutritional treatment interventions.

How Robust is the Evidence for a Role of Oxidative Stress in Autism Spectrum Disorders and Intellectual Disabilities?

Growing interest in the pathogenesis of autism spectrum disorders (ASDs) and other intellectual and developmental disabilities (IDD) has led to emerging evidence implicating a role for oxidative stress. However, understanding the strength of this association is made challenging by the use of a variety of purported biomarkers of oxidative stress, many of which have either uncertain specificity or flawed methods of analysis. This review aims to address this issue, which is widespread in the ASD and IDD literature, by providing readers with information concerning the strengths and limitations of the choice and analysis of biomarkers of oxidative stress. We highlight that biomarkers and assays should be specific, sensitive, reproducible, precise, robust, and chosen with careful consideration. Future studies should be sufficiently powered and address sample collection, processing, and storage which are, additionally, poorly considered, sources of bad practice, and potential errors. Only with these issues considered, will the data lead to conclusions as to the precise role of oxidative stress in ASDs and IDD.

Folic acid ameliorates neonatal isolation-induced autistic like behaviors in rats: epigenetic modifications of BDNF and GFAP promotors

The current study investigated the role of epigenetic dysregulation of brain derived neurotrophic factor (BDNF) and glial fibrillary acidic protein (GFAP) genes and oxidative stress as possible mechanisms of autistic-like behaviors in neonatal isolation model in rats and the impact of folic acid administration on these parameters. Forty Wistar albino pups were used as follows: control, folic acid administered, isolated, and isolated folic acid treated groups. Isolated pups were separated from their mothers for 90 min daily from postnatal day (PND) 1 to 11. Pups (isolated or control) received either the vehicle or folic acid (4 mg/kg/day) orally from PND 1 to 29. Behavioral tests were done from PND 30 to 35. Oxidative stress markers and antioxidant defense in the frontal cortex homogenate were determined. DNA methylation of BDNF and GFAP genes was determined by qPCR. Histopathological examination was carried out. Neonatal isolation produced autistic-like behaviors that were associated with BDNF and GFAP hypomethylation, increased oxidative stress, increased inflammatory cell infiltration, and structural changes in the frontal cortex. Folic acid administration concurrently with isolation reduced neonatal isolation-induced autistic-like behaviors, decreased oxidative stress, regained BDNF and GFAP gene methylation, and ameliorated structural changes in the frontal cortices of isolated folic acid treated rats. Novelty: Neonatal isolation induces "autistic-like" behavior and these behaviors are reversed by folic acid supplementation. Neonatal isolation induces DNA hypomethylation of BDNF and GFAP, increased oxidative stress markers, and neuroinflammation. All of these changes were reversed by daily folic acid supplementation.

Preparative isolation of 1,1-diphenyl-2-picrylhydrazyl inhibitors from Ribes himalense using medium-pressure and two-dimensional reversed-phase/reversed-phase liquid chromatography guided by an online HPLC-1, 1-diphenyl-2-picrylhydrazyl assay

The lack of suitable chromatographic purification methods makes it a challenge to effectively isolate the chemical components of traditional Tibetan medicines. Ribes himalense is a rarely studied Tibetan medicine, reputed to have free radical-scavenging effects. In the present work, we utilized it as a model herb to highlight an approach for the separation of 1,1-diphenyl-2-picrylhydrazyl inhibitors via medium-pressure chromatography and two-dimensional reversed-phase/reversed-phase interaction liquid chromatography under the guidance of an online high-performance liquid chromatography-1,1-diphenyl-2-picrylhydrazyl assay. Finally, we obtained two free radical inhibitors (>95% purity) from the R. himalense extract. This is the first report of the rapid isolation of these free radical inhibitors from R. himalense. This method can be useful in quality standard assessment and further pharmacological activity research, and may be used as a reference for the composition research of various natural products.

Improving Outcome in Infantile Autism with Folate Receptor Autoimmunity and Nutritional Derangements: A Self-Controlled Trial

Background

In contrast to multiple rare monogenetic abnormalities, a common biomarker among children with infantile autism and their parents is the discovery of serum autoantibodies directed to the folate receptor alpha (FRα) localized at blood-brain and placental barriers, impairing physiologic folate transfer to the brain and fetus. Since outcome after behavioral intervention remains poor, a trial was designed to treat folate receptor alpha (FRα) autoimmunity combined with correction of deficient nutrients due to abnormal feeding habits.

Methods

All participants with nonsyndromic infantile autism underwent a routine protocol measuring CBC, iron, vitamins, coenzyme Q10, metals, and trace elements. Serum FRα autoantibodies were assessed in patients, their parents, and healthy controls. A self-controlled therapeutic trial treated nutritional derangements with addition of high-dose folinic acid if FRα autoantibodies tested positive. The Childhood Autism Rating Scale (CARS) monitored at baseline and following 2 years of treatment was compared to the CARS of untreated autistic children serving as a reference.

Results

In this self-controlled trial (82 children; mean age ± SD: 4.4 ± 2.3 years; male:female ratio: 4.8:1), FRα autoantibodies were found in 75.6 % of the children, 34.1 % of mothers, and 29.4 % of fathers versus 3.3 % in healthy controls. Compared to untreated patients with autism (n=84) whose CARS score remained unchanged, a 2-year treatment decreased the initial CARS score from severe (mean ± SD: 41.34 ± 6.47) to moderate or mild autism (mean ± SD: 34.35 ± 6.25; paired t-test p<0.0001), achieving complete recovery in 17/82 children (20.7 %). Prognosis became less favorable with the finding of higher FRα autoantibody titers, positive maternal FRα autoantibodies, or FRα antibodies in both parents.

Conclusions

Correction of nutritional deficiencies combined with high-dose folinic acid improved outcome for autism, although the trend of a poor prognosis due to maternal FRα antibodies or FRα antibodies in both parents may warrant folinic acid intervention before conception and during pregnancy.

The Independent and Combined Effects of Omega-3 and Vitamin B12 in Ameliorating Propionic Acid Induced Biochemical Features in Juvenile Rats as Rodent Model of Autism

Metabolites of proper fatty acids modulate the inflammatory response and are essential for normal brain development; equally, abnormal fatty acid metabolism plays a critical role in the pathology of autism. Currently, dietary supplements are often used to improve the core symptoms of Autism spectrum disorder (ASD). The present study analyzed the effects of orally supplemented omega-3 (ω-3) and vitamin B12 on ameliorating oxidative stress and impaired lipid metabolism in a propionic acid (PPA)-induced rodent model of autism, together with their effect on the gut microbial composition, where great fluctuations in the bacterial number and strains were observed; interestingly, polyunsaturated fatty acids such as omega-3 induced higher growth of the gram-positive bacterium Staphylococcus aureus and decreased the survival rates of Clostridia sp. as well as other enteric bacterial strains. Thirty-five young male western albino rats were divided into five equal groups. The first group served as the control; the second group was given an oral neurotoxic dose of PPA (250 mg/kg body weight/day) for 3 days. The third group received an oral dose of ω-3 (200 mg/kg body weight/day) for 30 days after the 3-day PPA treatment. Group four was given an oral dose of vitamin B12 (16.7 mg/kg/day) for 30 days after PPA treatment. Finally, group five was given a combination of both ω-3 and vitamin B12 at the same dose for the same duration after PPA treatment. Biochemical parameters related to oxidative stress and impaired fatty acid metabolism were investigated in the brain homogenates of each group. The effects of the dietary supplements on the gut microbiota were also observed. The PPA-treated autistic model expressed significantly higher levels of lipid peroxides and 5-lipoxygenase (5-LOX) and significantly less glutathione (GSH), glutathione S-transferase (GST), and cyclooxygenase 2 (COX2) than the control group. However, a remarkable amelioration of most of the impaired markers was observed with oral supplementation with ω-3 and vitamin B12, either alone or in combination. Our results concluded that impairment at various steps of the lipid metabolic pathways may contribute to the development of autism; however, supplementation with ω-3 and vitamin B12 can result in a positive therapeutic effect.

Endogenous non-enzymatic antioxidants in the human body

The exposure of cells, tissues and extracellular matrix to harmful reactive species causes a cascade of reactions and induces activation of multiple internal defence mechanisms (enzymatic or non-enzymatic) that provide removal of reactive species and their derivatives. The non-enzymatic antioxidants are represented by molecules characterized by the ability to rapidly inactivate radicals and oxidants. This paper focuses on the major intrinsic non-enzymatic antioxidants, including metal binding proteins (MBPs), glutathione (GSH), uric acid (UA), melatonin (MEL), bilirubin (BIL) and polyamines (PAs).

Relevance of 4-F4t-neuroprostane and 10-F4t-neuroprostane to neurological diseases

F₄-neuroprostanes (F₄-NeuroPs) are non-enzymatic oxidized products derived from docosahexaenoic acid (DHA) and are suggested to be oxidative damage biomarkers of neurological diseases. However, 128 isomers can be formed from DHA oxidation and among them, 4(RS)-4-F_4t-NeuroP (4-F_4t-NeuroP) and 10(RS)-10-F_4t-NeuroP (10-F_4t-NeuroP) are the most studied. Here, we report the identification and the clinical relevance of 4-F_4t-NeuroP and 10-F_4t-NeuroP in plasma of four different neurological diseases, including multiple sclerosis (MS), autism spectrum disorders (ASD), Rett syndrome (RTT), and Down syndrome (DS). The identification and the optimization of the method were carried out by gas chromatography/negative-ion chemical ionization tandem mass spectrometry (GC/NICI-MS/MS) using chemically synthesized 4-F_4t-NeuroP and 10-F_4t-NeuroP standards and in oxidized DHA liposome. Both 4-F_4t-NeuroP and 10-F_4t-NeuroP were detectable in all plasma samples from MS (n = 16), DS (n = 16), ASD (n = 9) and RTT (n = 20) patients. While plasma 10-F_4t-NeuroP content was significantly higher in patients of all diseases as compared to age and gender matched healthy control subjects (n = 61), 4-F_4t-NeuroP levels were significantly higher in MS and RTT as compared to healthy controls. Significant positive relationships were observed between relative disease severity and 4-F_4t-NeuroP levels (r = 0.469, P <0.0001), and 10-F_4t-NeuroP levels (r = 0.757, P < 0.0001). The study showed that the plasma amount ratio of 10-F_4t-NeuroP to 4-F_4t-NeuroP and the plasma amount as individual isomer can be used to discriminate between different brain diseases. Overall, by comparing the different types of disease, our plasma data indicates that 4-F_4t-NeuroP and 10-F_4t -NeuroP: i) are biologically synthesized in vivo and circulated, ii) are related to clinical severity of neurological diseases, iii) are useful to identify shared pathogenetic pathways in distinct brain diseases, and iv) appears to be distinctive for different neurological conditions, thus representing potentially new biological disease markers. Our data strongly suggest that in vivo DHA oxidation follows preferential chemical rearrangements according to different brain diseases.