Jorge Guzmán-Muñiz

Regulation of neural stem cell in the human SVZ by trophic and morphogenic factors

The subventricular zone (SVZ), lining the lateral ventricular system, is the largest germinal region in mammals. In there, neural stem cells express markers related to astoglial lineage that give rise to new neurons and oligodendrocytes in vivo. In the adult human brain, in vitro evidence has also shown that astrocytic cells isolated from the SVZ can generate new neurons and oligodendrocytes. These proliferative cells are strongly controlled by a number of signals and molecules that modulate, activate or repress the cell division, renewal, proliferation and fate of neural stem cells. In this review, we summarize the cellular composition of the adult human SVZ (hSVZ) and discuss the increasing evidence showing that some trophic modulators strongly control the function of neural stem cells in the SVZ.

Synthetic Glucocorticoids Modulate Function of Neural Cells: Implications in Autoimmune Neurological Disorders

Glucocorticoids are hormones synthesized from cholesterol in the cortex of adrenal glands. Synthetic glucocorticoids are chemical derivatives synthesized from cholic acid obtained from cattle or steroid sapogenins. The chemical structure of these drugs is very similar to that of natural glucocorticoids. Therefore, the synthetic derivatives efficiently bind to intracellular receptors of glucocorticoid and mineralocorticoid, which promote a myriad of transcriptional and non-transcriptional processes. Synthetic glucocorticoids can trigger a cascade of events including neurotransmitter modulation, protein expression, neuronal firing or neurite growth. In addition, these substances are some of the most potent antiinflammatory and immunosuppressive agents available in human medicine with a good drug safety profile in humans. Thus, they are a valuable pharmacological tool for the treatment of acute and chronic neuroinflammation, and autoimmune disorders with neurological involvement. However, increasing evidence indicates that a high-dose or a long-term delivery of synthetic glucocorticoids may promote cognitive dysfunction, memory impairment, apoptosis, systemic hypersensitivity, urticaria-angioedema, neuronal degeneration, cerebral atrophy, major depression or steroid psychosis. Yet, these major side effects are relatively infrequent, the unrestricted use of glucocorticoids has to be avoided and systematic neuropsychological assessments are recommended to detect early neurological impairment. Herein, we discuss the mechanisms by which synthetic glucocorticoids may induce neural degeneration and other pathological changes in different brain regions. In addition, we describe the role of glucocorticoids in some autoimmune neurological disorders.