China
Africa
Explore chapters and articles related to this topic
The inherited basis of hypergonadotropic hypogonadism
Published in Philip E. Harris, Pierre-Marc G. Bouloux, Endocrinology in Clinical Practice, 2014
The clinical phenotypes of PROKR2/PROK2 mutations, encoding prokineticin receptor-2 and prokineticin-2, respectively, range from both classical KS to normosmic hypogonadotropic hypogonadism.59 Nonreproductive phenotypes include fibrous dysplasia, bimanual synkinesia, and epilepsy. Patients with the more severe reproductive dysfunction tend to have biallelic mutations in PROK2/PROKR2 and fewer associated nonreproductive abnormalities. Patients with monoallelic mutations have less severe reproductive dysfunction and more nonreproductive abnormalities. The PROKR2 is a G protein–coupled receptor that binds to the ligand PROK2. Mouse prok2 knockout models have small, abnormally shaped olfactory bulbs with an accumulation of neurons in the rostral migratory stream (RMS) between the sub-ventricular zone and the olfactory bulb.60
Imaging Cell Trafficking with MR Imaging
Published in Martin G. Pomper, Juri G. Gelovani, Benjamin Tsui, Kathleen Gabrielson, Richard Wahl, S. Sam Gambhir, Jeff Bulte, Raymond Gibson, William C. Eckelman, Molecular Imaging in Oncology, 2008
Assaf A. Gilad, Piotr Walczak, Jeff W. M. Bulte, Michael T. McMahon
Although the human body appears to be static, with defined and anatomically distinct organ systems, there are continuous dynamic processes of cell replacement, repair, and immune-mediated cell infiltrations. All these processes involve cell trafficking. Trafficking cells are cells navigating the body in response to different stimuli; some are chemoattractive and others are chemorepulsive. Perhaps the most pronounced example of cell trafficking is within the hematopoietic system, where cells traffic throughout the entire body. Leukocytes enter the circulation from the bone marrow, spleen, lymph nodes, or the thymus and travel to sites of inflammation and immune stimulation in a highly regulated fashion (1). Recently, it has been shown that circulating endothelial progenitor cells (EPCs) can be recruited from the blood and participate in angioneogenesis of infarcted heart (2). Even in an organ considered incapable of any regenerative activity, such as the postnatal brain, neurogenic regions (the hippocampus and the subventricular zone) remain active throughout life and generate a significant number of new neurons that participate in cell trafficking. Notably, in rodents, subventricular zone neurons migrate extensively, navigating along the rostral migratory stream to reach their final destination, the olfactory bulb (3). Thus, even after full postnatal development, cell trafficking is a key biological phenomenon. In this chapter, we will illustrate how magnetic resonance (MR) imaging may be applied to obtain a deeper insight into the processes that govern cell migration, in particular as it relates to cancer.
Neurogenesis in the Adult and Aging Brain
Published in David R. Riddle, Brain Aging, 2007
David R. Riddle, Robin J. Lichtenwalner
Quantitatively, the extent of adult neurogenesis in the hippocampus is only a fraction of that in the anterior portion of the adult subventricular zone (SVZ), a thin, persistent remnant of the secondary proliferative zone of the developing brain. Although not readily identifiable by cell-type specific markers, neural stem cells can be isolated from the adult SVZ and shown in culture to be both self-renewing and multipotent, capable of generating both neurons and glia. Studies indicate that the neural stem cells have some characteristics of astrocytes, but clearly not all astrocytes in the region are neural stem cells [34–36]. Extensive analysis of the adult SVZ indicates that the region comprises several cell types in addition to the slowly dividing stem cells, including a more rapidly dividing population of transit amplifying progenitor (TAP) cells, neuroblasts, glial cells, and a monolayer of ependymal cells lining the ventricle [35]. Neuroblasts born in the SVZ maintain the ability to proliferate as they migrate through the SVZ, into the rostral migratory stream (RMS), and anteriorly to the olfactory bulb (OB), finally differentiating into interneurons (e.g., [37–40]). Throughout their migration, chains of neuroblasts are ensheathed by slowly proliferating astrocytes, which presumably help maintain an appropriate microenvironment for migration and cell division. The division of neuroblasts within the RMS, far from the SVZ, demonstrates that the environment that supports the division of neuronal progenitors is much more extensive in the SVZ/RMS than in the DG, where the division of progenitor cells is spatially restricted. It also is important to note that the stem/progenitor cell populations differ between the SVZ and the SGZ [41], and that the progenitor population in the adult hippocampus lacks true stem cells, containing only more restricted progenitor cells [42, 43].
A role for flavonoids in the prevention and/or treatment of cognitive dysfunction, learning, and memory deficits: a review of preclinical and clinical studies
Published in Nutritional Neuroscience, 2023
Matin Ramezani, Arman Zeinaddini Meymand, Fariba Khodagholi, Hamed Mohammadi Kamsorkh, Ehsan Asadi, Mitra Noori, Kimia Rahimian, Ali Saberi Shahrbabaki, Aisa Talebi, Hanieh Parsaiyan, Sepideh Shiravand, Niloufar Darbandi
Accumulating research has provided clear evidence of neurogenesis in subgranular zone (SGZ) and subventricular zone (SVZ). At the SVZ, neural stem cells (NSCs) travel to the rostral migratory stream and differentiate into interneurons in the olfactory bulb. NSCs located in the SGZ give rise to granular neurons that integrate into functional circuits in the hippocampus [36,37]. By activation of neurogenesis, flavonoids such as luteolin [38] and spinosin [39] can have beneficial effects on learning and memory function. Intraperitoneal administration of luteolin in the Ts65Dn mouse model with Down syndrome enhanced hippocampal cell proliferation and neurogenesis and improved cognition, learning and memory [Morris water maze (MWM) and Novel object recognition tasks] [38]. Spinosin administration in male ICR mice promoted the proliferation of NSCs and the survival and differentiation of newborn neurons in the hippocampal DG region and also improved cognitive performance (passive avoidance task) compared with vehicle mice [39].
Progress in gene and cell therapies for the neuronal ceroid lipofuscinoses
Published in Expert Opinion on Biological Therapy, 2018
Anthony Donsante, Nicholas M Boulis
Tamaki et al. evaluated the efficacy of human CNS-derived stem cells for the treatment of CLN1 in a mouse model of the disease. These cells are self-renewing and can differentiate into a variety of neural and glial cell types in vivo [20]. To first look at the fate of the cells and their potential to aggravate the disease, 8 × 105 cells were transplanted into immunocompromised PPT1−/− neonates at sites in the anterior cortex, cerebellum, and lateral ventricles [21]. Donor cells were mainly found in the subventricular zone and rostral migratory stream and to a lesser extent in the cortex. In different brain regions, the cells took on different cell types: neurons in the olfactory bulb, astrocytes near the subventricular zone and corpus callosum, and oligodendrocytes in white matter tracts, but appeared undifferentiated in the cortex. Cortical cells showed limited proliferation at the time of analysis. The transplanted cells did not appear to appreciably alter the activation of microglia at this dose.
Aberrant plasticity in the hippocampus after neonatal seizures
Published in International Journal of Neuroscience, 2018
Xiaoqian Zhang, Huiling Qu, Ying Wang, Shanshan Zhao, Ting Xiao, Chuansheng Zhao, Weiyu Teng
During the past century, it has become accepted that neural stem cells exist in two main neurogenic regions in the adult brain, the subgranular zone (SGZ) of the dentate gyrus and the subventricular zone (SVZ); these are both capable of generating new neurons continuously throughout life [1,2]. The newly generated neuroblasts in the SVZ migrate towards the olfactory bulb through the rostral migratory stream, where they differentiate into granule cells or periglomerular cells in the olfactory bulb, which reside in the granule cell layer or glomerula, respectively. The progenitor cells within the SGZ of the dentate gyrus proliferate and differentiate into dentate granule cells (DGCs), and these newly generated DGCs in turn integrate into the mature hippocampal neuronal network. Eventually, these new neurons from SVZ and SGZ appear to have similar morphological, physiological and functional features as mature neurons [3]. The process of adult neurogenesis can be influenced by a variety of physiological and pathological stimuli, including brain injury, stress, aging, genetics and exercise [4–8]. For example, seizures induced by chemicals or electrical stimulation can result in aberrant neurogenesis [9–12].