Existence of a potential neurogenic system in the adult human brain

Abstract

BackgroundPrevailingly, adult mammalian neurogenesis is thought to occur in discrete, separate locations known as neurogenic niches that are best characterized in the subgranular zone (SGZ) of the dentate gyrus and in the subventricular zone (SVZ). The existence of adult human neurogenic niches is controversial.MethodsThe existence of neurogenic niches was investigated with neurogenesis marker immunostaining in histologically normal human brains obtained from autopsies. Twenty-eight adult temporal lobes, specimens from limbic structures and the hypothalamus of one newborn and one adult were examined.ResultsThe neural stem cell marker nestin stained circumventricular organ cells and the immature neuronal marker doublecortin (DCX) stained hypothalamic and limbic structures adjacent to circumventricular organs; both markers stained a continuous structure running from the hypothalamus to the hippocampus. The cell proliferation marker Ki-67 was detected predominately in structures that form the septo-hypothalamic continuum. Nestin-expressing cells were located in the fimbria-fornix at the insertion of the choroid plexus; ependymal cells in this structure expressed the putative neural stem cell marker CD133. From the choroidal fissure in the temporal lobe, a nestin-positive cell layer spread throughout the SVZ and subpial zone. In the subpial zone, a branch of this layer reached the hippocampal sulcus and ended in the SGZ (principally in the newborn) and in the subiculum (principally in the adults). Another branch of the nestin-positive cell layer in the subpial zone returned to the optic chiasm. DCX staining was detected in the periventricular and middle hypothalamus and more densely from the mammillary body to the subiculum through the fimbria-fornix, thus running through the principal neuronal pathway from the hippocampus to the hypothalamus. The column of the fornix forms part of this pathway and appears to coincide with the zone previously identified as the human rostral migratory stream. Partial co-labeling with DCX and the neuronal marker βIII-tubulin was also observed.ConclusionsCollectively, these findings suggest the existence of an adult human neurogenic system that rises from the circumventricular organs and follows, at minimum, the circuitry of the hypothalamus and limbic system.

Multimodality Monitoring, Inflammation, and Neuroregeneration in Subarachnoid Hemorrhage

“…Our study suggests that this correlation may be significant, because we have shown that the human brain expresses neurogenesis markers in a continuous area between the hippocampus and hypothalamus 26. This area is larger than previously thought and involves the circumventricular organs, where the BBB is absent.…”

“…This figure displays figures from histologically normal brains analyzed in our previous study,26 which showed the existence of a potential neurogenic system between the hypothalamus and the hippocampus. A and B are brain specimens showing the choroid plexus (1) and the fimbria (2), which are structures in the hypothalamus-hippocampus axis that express neurogenesis markers 26. The BBB is normally absent in the choroid plexus and in the neurovascular unit during brain injury, which may indicate a role of the neurovascular unit in injury-induced neurogenesis.…”

Characterization of neural stem cells and their progeny in the sensory circumventricular organs of adult mouse

“…CC central canal, 3 V third ventricle diet-induced obesity model rodents (McNay et al 2012). Recently, the occurrence of NSCs and NPCs has been demonstrated in the ME and Arc of adult human brains (Sanin et al 2013;Nogueira et al 2014;Batailler et al 2014).…”

Hepatocellular carcinoma may display elevated nestin expression in endothelial cells: experimental study

“…Indeed, in the human exocrine pancreas, nestin-positive endothelial cells are adjacent to regions in the ductal epithelium that harbor putative islet progenitor cells. 15 Furthermore, in our previous study, 12 One caveat of our study is that we only used one hepatocellular carcinoma case, yet the lack of information regarding a subject with such relevance and the results presented here warrant this report. For instance, although hepatocellular carcinoma is the fifth most frequent tumor type, its prognosis is highly heterogeneous.…”