Brain Response to Injury and Neurodegeneration

Oxidative stress parameters and antioxidants in patients with bipolar disorder: Results from a meta-analysis comparing patients, including stratification by polarity and euthymic status, with healthy controls

OBJECTIVE

To investigate oxidative stress markers and antioxidants in bipolar disorder (BD).

METHODS

Electronic MEDLINE/PubMed/Cochrane-Library/Scopus/TripDatabase search until 06/30/2019 for studies comparing antioxidant or oxidative stress markers between BD and healthy controls (HCs). Standardized mean differences (SMD) and 95% confidence intervals (CIs) were calculated for ≥3 studies.

RESULTS

Forty-four studies (n = 3,767: BD = 1,979; HCs = 1,788) reported on oxidative stress markers malondialdehyde (MDA), thiobarbituric acid reactive substances (TBARS), and total nitrites; antioxidants glutathione (GSH), uric acid, and zinc; or antioxidantenhancing enzymes superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX), and GSH-transferase (GST). Compared with HCs, BD was associated with higher GST (P = .01), CAT (P = .02), nitrites (P < .0001), TBARS (P < .0001), MDA (P = .01), uric acid (P < .0001), and lower GSH (P = .006), without differences in SOD, GPX, and zinc. Compared to HCs, levels were higher in BD-mania for TBARS (P < .0001) and uric acid (P < .0001); in BD-depression for TBARS (P = .02); and BD-euthymia for uric acid (P = .03). Uric acid levels were higher in BD-mania vs BD-depression (P = .002), but not vs BD euthymia. TBARS did not differ between BD-mania and BD-depression. Medication-free BD-mania patients had higher SOD (P = .02) and lower GPX (P < .0001) than HCs. After treatment, BD did not differ from HCs regarding SOD and GPX.

CONCLUSIONS

Beyond a single biomarker of oxidative stress, the combination of several parameters appears to be more informative for BD in general and taking into account illness polarity. BD is associated with an imbalance in oxidative stress with some phase-specificity for uric acid and TBARS and possible treatment benefits for SOD and GPX. Future studies should take into account confounding factors that can modify oxidative stress status and simultaneously measure oxidative stress markers and antioxidants including different blood sources.

A More Comprehensive Approach to the Neuroprotective Potential of Long-Chain Polyunsaturated Fatty Acids in Preterm Infants Is Needed-Should We Consider Maternal Diet and the n-6:n-3 Fatty Acid Ratio?

There is growing evidence that long-chain polyunsaturated fatty acids (LCPUFAs) are of importance for normal brain development. Adequate supply of LCPUFAs may be particularly important for preterm infants, because the third trimester is an important period of brain growth and accumulation of arachidonic acid (n-6 LCPUFA) and docosahexaenoic acid (n-3 LCPUFA). Fatty acids from the n-6 and n-3 series, particularly, have important functions in the brain as well as in the immune system, and their absolute and relative intakes may alter both the risk of impaired neurodevelopment and response to injury. This narrative review focuses on the potential importance of the n-6:n-3 fatty acid ratio in preterm brain development. Randomized trials of post-natal LCPUFA supplementation in preterm infants are presented. Pre-clinical evidence, results from observational studies in preterm infants as well as studies in term infants and evidence related to maternal diet during pregnancy, focusing on the n-6:n-3 fatty acid ratio, are also summarized. Two randomized trials in preterm infants have compared different ratios of arachidonic acid and docosahexaenoic acid intakes. Most of the other studies in preterm infants have compared formula supplemented with arachidonic acid and docosahexaenoic acid to un-supplemented formula. No trial has had a comprehensive approach to differences in total intake of both n-6 and n-3 fatty acids during a longer period of neurodevelopment. The results from preclinical and clinical studies indicate that intake of LCPUFAs during pregnancy and post-natal development is of importance for neurodevelopment and neuroprotection in preterm infants, but the interplay between fatty acids and their metabolites is complex. The best clinical approach to LCPUFA supplementation and n-6 to n-3 fatty acid ratio is still far from evident, and requires in-depth future studies that investigate specific fatty acid supplementation in the context of other fatty acids in the diet.

VBP15, a novel anti-inflammatory and membrane-stabilizer, improves muscular dystrophy without side effects

Absence of dystrophin makes skeletal muscle more susceptible to injury, resulting in breaches of the plasma membrane and chronic inflammation in Duchenne muscular dystrophy (DMD). Current management by glucocorticoids has unclear molecular benefits and harsh side effects. It is uncertain whether therapies that avoid hormonal stunting of growth and development, and/or immunosuppression, would be more or less beneficial. Here, we discover an oral drug with mechanisms that provide efficacy through anti-inflammatory signaling and membrane-stabilizing pathways, independent of hormonal or immunosuppressive effects. We find VBP15 protects and promotes efficient repair of skeletal muscle cells upon laser injury, in opposition to prednisolone. Potent inhibition of NF-κB is mediated through protein interactions of the glucocorticoid receptor, however VBP15 shows significantly reduced hormonal receptor transcriptional activity. The translation of these drug mechanisms into DMD model mice improves muscle strength, live-imaging and pathology through both preventive and post-onset intervention regimens. These data demonstrate successful improvement of dystrophy independent of hormonal, growth, or immunosuppressive effects, indicating VBP15 merits clinical investigation for DMD and would benefit other chronic inflammatory diseases.

Following experimental stroke, the recovering brain is vulnerable to lipoxygenase-dependent semaphorin signaling

Recovery from stroke is limited, in part, by an inhibitory environment in the postischemic brain, but factors preventing successful remodeling are not well known. Using cultured cortical neurons from mice, brain endothelial cells, and a mouse model of ischemic stroke, we show that signaling from the axon guidance molecule Sema3A via eicosanoid second messengers can contribute to this inhibitory environment. Either 90 nM recombinant Sema3A, or the 12/15-lipoxygenase (12/15-LOX) metabolites 12-HETE and 12-HPETE at 300 nM, block axon extension in neurons compared to solvent controls, and decrease tube formation in endothelial cells. The Sema3A effect is reversed by inhibiting 12/15-LOX, and neurons derived from 12/15-LOX-knockout mice are insensitive to Sema3A. Following middle cerebral artery occlusion to induce stroke in mice, immunohistochemistry shows both Sema3A and 12/15-LOX are increased in the cortex up to 2 wk. To determine whether a Sema3A-dependent damage pathway is activated following ischemia, we injected recombinant Sema3A into the striatum. Sema3A alone did not cause injury in normal brains. But when injected into postischemic brains, Sema3A increased cortical damage by 79%, and again, this effect was reversed by 12/15-LOX inhibition. Our findings suggest that blocking the semaphorin pathway should be investigated as a therapeutic strategy to improve stroke recovery.

Neuroprotection by hypothalamic peptide proline-rich peptide-1 in Abeta25-35 model of Alzheimer's disease

BACKGROUND

This work sought to determine the effects of hypothalamic proline-rich peptide (PRP)-1 in a rat model of Alzheimer's disease.

METHODS

Complex histochemical, electrophysiologic, and behavioral analyses were performed on intact or diseased Wistar rats (n = 28). Pathologic conditions were induced by bilateral intracerebroventricular injection of amyloid peptide Abeta25-35. The diseased rats received systemic administration of PRP-1 or placebo control.

RESULTS

Abeta25-35 caused cellular neurodegeneration with marked glial reaction in the hippocampal complex and almost full destruction of the dentate fascia, which was not observed in conditions of PRP-1 administration after Abeta25-35 injection. Hippocampal neurons of intact animals responded to high-frequency (tetanic) stimulation of entorhinal cortex of ipsilateral cerebral hemisphere by tetanic and posttetanic potentiation of a different intensity and duration, which was accompanied by posttetanic depression. Abeta25-35 led to significant changes in the level and pattern of hippocampal neuronal activity, indicating the absence of both tetanic and posttetanic activity. Poststimulus activity manifestations rarely occurred and rapidly decreased after repeated trials. This indicated the focal character of lesion. Regular administration of PRP-1 for 4 weeks resulted in optimal restoration of electrophysiologic parameters. PRP-1 maintained the initial learning level achieved in a behavioral study in a Morris water maze.

CONCLUSIONS

Systemic administration of PRP-1 possesses neuroprotective effects and can prevent the neurodegeneration in hippocampus induced by Abeta25-35. This suggests that PRP-1 could be a potential therapeutic agent for specific neurodegenerative diseases.