Current Neurogenic and Neuroprotective Strategies to Prevent and Treat Neurodegenerative and Neuropsychiatric Disorders

The Role of Hyperbaric Oxygen Therapy in Neuroregeneration and Neuroprotection: A Review

Neurogenesis is a high energy-demanding process, which is why blood vessels are an active part of the neurogenic niche since they allow the much-needed oxygenation of progenitor cells. In this regard, although neglected for a long time, the "oxygen niche" should be considered an important intervenient in adult neurogenesis. One possible hypothesis for the failure of numerous neuroprotective trials is that they relied on compounds that target a highly specific neuroprotective pathway. This approach may be too limited, given the complexity of the processes that lead to cell death. Therefore, research should adopt a more multifactorial approach. Among the limited range of agents with multimodal neuromodulatory capabilities, hyperbaric oxygen therapy has demonstrated effectiveness in reducing secondary brain damage in various brain injury models. This therapy functions not only as a neuroprotective mechanism but also as a powerful neuroregenerative mechanism.

The Role of Docosahexaenoic Acid (DHA) on Cognitive Functions in Psychiatric Disorders

Cognitive impairment is strongly associated with functional outcomes in psychiatric patients. Involvement of n-3 long chain polyunsaturated fatty acid (n-3 LC-PUFA), in particular docosahexaenoic acid (DHA), in brain functions is largely documented. DHA is incorporated into membrane phospholipids as structural component, especially in the central nervous system where it also has important functional effects. The aim of this review is to investigate the relationship between DHA and cognitive function in relation to mental disorders. Results from few randomized controlled trials (RCTs) on the effects of DHA (alone or in combination) in psychotic, mood and neurodevelopmental disorders, respectively, suggest that no conclusive remarks can be drawn.

Repeated restraint stress upregulates rat sulfotransferase 1A1

BackgroundSulfotransferases (SULTs) are phase II drug-metabolizing enzymes. SULTs also regulate the biological activities of biological signaling molecules, such as various hormones, bile acids, and monoamine neurotransmitters; therefore, they play critical roles in the endocrine and nervous systems. People are subject to various kinds of physical, chemical, toxicological, physiological, and psychological stresses at one time or another. The study of the effects produced by stress may lead to finding novel remedies for many disease conditions. The effect of repeated restraint stress on rat SULT expression has not been studied. MethodsThis study involves the effect of repeated restraint stress on SULT1A1 expressions. Male Sprague-Dawley rats (n=4) were subjected to repeated restraint stress 2 h/day for 7 days. Protein and RNA expression of SULT1A1 were analyzed by western blot and quantitative real time reverse transcription polymerase chain reaction, respectively, in important tissues. ResultsWe observed that repeated restraint stress increased the expression of SULT1A1 in the liver, adrenal glands, cerebellum, hypothalamus, and cerebral cortex in male rats. Patterns of enhanced expression were observed at both mRNA and protein level, indicating that repeated restraint stress stimulates enzyme expression at the transcriptional level. ConclusionsChanges of SULT1A1 expression in important tissues caused by repeated restraint stress will have a significant effect on drug metabolism and xenobiotics detoxification. The significant changes in endocrine glands and brain sections may also cause disturbances in hormone homeostasis, therefore leading to disease conditions. This report provides clues for the understanding of the effect of stresses on health.

CD271+, CXCR7+, CXCR4+, and CD133+ Stem/Progenitor Cells and Clinical Characteristics of Acute Ischemic Stroke Patients

Ischemic stroke causes mobilization of various groups of progenitor cells from bone marrow to bloodstream and this correlates with the neurological status of stroke patients. The goal of our study was to identify the activity of chosen progenitor/stem cells in the peripheral blood of acute ischemic stroke patients in the first 7 days after the incident, through associations between the levels of the cells and clinical features of the patients. Thirty-three acute ischemic stroke patients and 15 non-stroke control subjects had their venous blood collected repeatedly in order to assess the levels of the CD45–CD34 + CD271+, the CD45–CD34 + CXCR4+, the CD45–CD34 + CXCR7+, and the CD45–CD34 + CD133+ stem/progenitor cells by means of flow cytometry. The patients underwent repeated neurological and clinical assessments, pulse wave velocity (PWV) assessment on day 5, and MRI on day 1 and 5 ± 2. The levels of the CD45–CD34 + CXCR7+ and the CD45–CD34 + CD271+ cells were lower in the stroke patients compared with the control subjects. Only the CD45–CD34 + CD271+ cells correlated positively with lesion volume in the second MRI. The levels of the CD45–CD34 + CD133+ cells on day 2 correlated negatively with PWV and NIHSS score on day 9. The patients whose PWV was above 10 m/s had significantly higher levels of the CD45–CD34 + CXCR4+ and the CD45–CD34 + CXCR7+ cells on day 1 than those with PWV below 10 m/s. This study discovers possible activity of the CD45–CD34 + CD271+ progenitor/stem cells during the first 7 days after ischemic stroke, suggests associations of the CD45–CD34 + CD133+ cells with the neurological status of stroke patients, and some activity of the CD45–CD34 + CD133+, the CD45–CD34 + CXCR4+, and the CD45–CD34 + CXCR7+ progenitor/stem cells in the process of arterial remodeling.

Harnessing migraines for neural regeneration

The success of naturalistic or therapeutic neuroregeneration likely depends on an internal milieu that facilitates the survival, proliferation, migration, and differentiation of stem cells and their assimilation into neural networks. Migraine attacks are an integrated sequence of physiological processes that may protect the brain from oxidative stress by releasing growth factors, suppressing apoptosis, stimulating neurogenesis, encouraging mitochondrial biogenesis, reducing the production of oxidants, and upregulating antioxidant defenses. Thus, the migraine attack may constitute a physiologic environment conducive to stem cells. In this paper, key components of migraine are reviewed – neurogenic inflammation with release of calcitonin gene-related peptide (CGRP) and substance P, plasma protein extravasation, platelet activation, release of serotonin by platelets and likely by the dorsal raphe nucleus, activation of endothelial nitric oxide synthase (eNOS), production of brain-derived neurotrophic factor (BDNF) and, in migraine aura, cortical spreading depression – along with their potential neurorestorative aspects. The possibility is considered of using these components to facilitate successful stem cell transplantation. Potential methods for doing so are discussed, including chemical stimulation of the TRPA1 ion channel, conjoint activation of a subset of migraine components, invasive and noninvasive deep brain stimulation of the dorsal raphe nucleus, transcranial focused ultrasound, and stimulation of the Zusanli (ST36) acupuncture point.

Exploring the potential of natural and synthetic neuroprotective steroids against neurodegenerative disorders: A literature review

Neurodegeneration is a complex process, which leads to progressive brain damage due to loss of neurons. Despite exhaustive research, the cause of neuronal loss in various degenerative disorders is not entirely understood. Neuroprotective steroids constitute an important line of attack, which could play a major role against the common mechanisms associated with various neurodegenerative disorders like Alzheimer's disease, Parkinson's disease, Huntington's disease, and amyotrophic lateral sclerosis. Natural endogenous steroids induce the neuroprotection by protecting the nerve cells from neuronal injury through multiple mechanisms, therefore the structural modifications of the endogenous steroids could be helpful in the generation of new therapeutically useful neuroprotective agents. The review article will keep the readers apprised of the detailed description of natural as well as synthetic neuroprotective steroids from the medicinal chemistry point of view, which would be helpful in drug discovery efforts aimed toward neurodegenerative diseases.

Bile Acids in Neurodegenerative Disorders

Bile acids, a structurally related group of molecules derived from cholesterol, have a long history as therapeutic agents in medicine, from treatment for primarily ocular diseases in ancient Chinese medicine to modern day use as approved drugs for certain liver diseases. Despite evidence supporting a neuroprotective role in a diverse spectrum of age-related neurodegenerative disorders, including several small pilot clinical trials, little is known about their molecular mechanisms or their physiological roles in the nervous system. We review the data reported for their use as treatments for neurodegenerative diseases and their underlying molecular basis. While data from cellular and animal models and clinical trials support potential efficacy to treat a variety of neurodegenerative disorders, the relevant bile acids, their origin, and the precise molecular mechanism(s) by which they confer neuroprotection are not known delaying translation to the clinical setting.