Exogenous Antioxidants in Remyelination and Skeletal Muscle Recovery.

Inflammatory, oxidative, and autoimmune responses cause severe damage to the nervous system inducing loss of myelin layers or demyelination. Even though demyelination is not considered a direct cause of skeletal muscle disease there is extensive damage in skeletal muscles following demyelination and impaired innervation. In vitro and in vivo evidence using exogenous antioxidants in models of demyelination is showing improvements in myelin formation alongside skeletal muscle recovery. For instance, exogenous antioxidants such as EGCG stimulate nerve structure maintenance, activation of glial cells, and reduction of oxidative stress. Consequently, this evidence is also showing structural and functional recovery of impaired skeletal muscles due to demyelination. Exogenous antioxidants mostly target inflammatory pathways and stimulate remyelinating mechanisms that seem to induce skeletal muscle regeneration. Therefore, the aim of this review is to describe recent evidence related to the molecular mechanisms in nerve and skeletal muscle regeneration induced by exogenous antioxidants. This will be relevant to identifying further targets to improve treatments of neuromuscular demyelinating diseases.

Taurine and Astrocytes: A Homeostatic and Neuroprotective Relationship.

Taurine is considered the most abundant free amino acid in the brain. Even though there are endogenous mechanisms for taurine production in neural cells, an exogenous supply of taurine is required to meet physiological needs. Taurine is required for optimal postnatal brain development; however, its brain concentration decreases with age. Synthesis of taurine in the central nervous system (CNS) occurs predominantly in astrocytes. A metabolic coupling between astrocytes and neurons has been reported, in which astrocytes provide neurons with hypotaurine as a substrate for taurine production. Taurine has antioxidative, osmoregulatory, and anti-inflammatory functions, among other cytoprotective properties. Astrocytes release taurine as a gliotransmitter, promoting both extracellular and intracellular effects in neurons. The extracellular effects include binding to neuronal GABAA and glycine receptors, with subsequent cellular hyperpolarization, and attenuation of N-methyl-D-aspartic acid (NMDA)-mediated glutamate excitotoxicity. Taurine intracellular effects are directed toward calcium homeostatic pathway, reducing calcium overload and thus preventing excitotoxicity, mitochondrial stress, and apoptosis. However, several physiological aspects of taurine remain unclear, such as the existence or not of a specific taurine receptor. Therefore, further research is needed not only in astrocytes and neurons, but also in other glial cells in order to fully comprehend taurine metabolism and function in the brain. Nonetheless, astrocyte's role in taurine-induced neuroprotective functions should be considered as a promising therapeutic target of several neuroinflammatory, neurodegenerative and psychiatric diseases in the near future. This review provides an overview of the significant relationship between taurine and astrocytes, as well as its homeostatic and neuroprotective role in the nervous system.

Laminin as a Biomarker of Blood-Brain Barrier Disruption under Neuroinflammation: A Systematic Review.

Laminin, a non-collagenous glycoprotein present in the brain extracellular matrix, helps to maintain blood-brain barrier (BBB) integrity and regulation. Neuroinflammation can compromise laminin structure and function, increasing BBB permeability. The aim of this paper is to determine if neuroinflammation-induced laminin functional changes may serve as a potential biomarker of alterations in the BBB. The 38 publications included evaluated neuroinflammation, BBB disruption, and laminin, and were assessed for quality and risk of bias (protocol registered in PROSPERO; CRD42020212547). We found that laminin may be a good indicator of BBB overall structural integrity, although changes in expression are dependent on the pathologic or experimental model used. In ischemic stroke, permanent vascular damage correlates with increased laminin expression (ß and γ subunits), while transient damage correlates with reduced laminin expression (α subunits). Laminin was reduced in traumatic brain injury and cerebral hemorrhage studies but increased in multiple sclerosis and status epilepticus studies. Despite these observations, there is limited knowledge about the role played by different subunits or isoforms (such as 411 or 511) of laminin in maintaining structural architecture of the BBB under neuroinflammation. Further studies may clarify this aspect and the possibility of using laminin as a biomarker in different pathologies, which have alterations in BBB function in common.

The Association of Sleep Disorders, Obesity and Sleep-Related Hypoxia with Cancer.

BACKGROUND: Sleep disorders have emerged as potential cancer risk factors. OBJECTIVE: This review discusses the relationships between sleep, obesity, and breathing disorders with concomitant risks of developing cancer. RESULTS: Sleep disorders result in abnormal expression of clock genes, decreased immunity, and melatonin release disruption. Therefore, these disorders may contribute to cancer development. Moreover, in sleep breathing disorder, which is frequently experienced by obese persons, the sufferer experiences intermittent hypoxia that may stimulate cancer cell proliferation. DISCUSSION: During short- or long- duration sleep, sleep-wake rhythm disruption may occur. Insomnia and obstructive sleep apnea increase cancer risks. In short sleepers, an increased risk of stomach cancer, esophageal squamous cell cancer, and breast cancer was observed. Among long sleepers (>9 hours), the risk of some hematologic malignancies is elevated. CONCLUSION: Several factors including insomnia, circadian disruption, obesity, and intermittent hypoxia in obstructive sleep apnea are contributing risk factors for increased risk of several types of cancers. However, further studies are needed to determine the more significant of these risk factors and their interactions.

Igf-ii y la gonddotropina coriónica regulan la roliferación, migración e invassión de células de trofoblasto humano / IGF-II and Chorionic Gonadotropin Regulate Proliferation, Migration and Invasion of Human Trophoblast Cells

Son conocidas las propiedades del factor de crecimiento similar a la insulina tipo II (IGF-II) y de la hormona gonadotropina coriónica (hCG) en implantación y migración trofoblástica; sin embargo, los mecanismos moleculares a través de los cuales ejercen sus efectos no están completamente caracterizados. El objetivo de este estudio fue establecer la interacción potencial entre los efectos funcionales de hCG e IGF-II en la regulación de la proliferación, migración e invasión trofoblástica. Utilizando la línea celular HTR-8/SVneo de trofoblasto extravelloso se estableció que IGF-II promueve la proliferación celular y de manera novedosa se demostró que hCG, a concentraciones elevadas, es capaz de estimular la proliferación trofoblástica, a través de un mecanismo independiente al empleado por IGF-II. En contraste, la capacidad invasiva del trofoblasto fue regulada por IGF-II y hCG, planteando la existencia de un efecto aditivo en sus acciones. En conclusión, nuestros resultados demuestran el papel de hCG e IGF-II en la regulación de la proliferación e invasión del trofoblasto y plantean la existencia de interacciones a nivel de sus acciones biológicas, contribuyendo a un mejor entendimiento de la biología del trofoblasto y sus patologías.

Both IGF-II and chorionic gonadotropin (hCG) are important regulators of human trophoblast migration and implantation; however the molecular mechanisms are not fully understood. The purpose of this study was to determine the potential cross-talk between functional effects of hCG and IGF-II in the regulation of trophoblast proliferation, migration and invasion. Using the HTR-8/SVneo trophobast cell line we found that IGF-II stimulates cell proliferation and, for the first time we demonstrate that hCG at high doses is able to promote trophoblast proliferation through a mechanism independent of IGF-II. In contrast, trophoblast invasiveness was regulated by both IGF-II and hCG and an additive effect between the two hormones was observed. In conclusion, our results demonstrate cross-talk between the biological activities of IGF-II and hCG in the regulation of trophoblast invasiveness and contribute to a better understanding of the trophoblast biology and pathology.