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Revolutionary Approaches of Induced Stem Cells in Disease Prevention
Published in Jyoti Ranjan Rout, Rout George Kerry, Abinash Dutta, Biotechnological Advances for Microbiology, Molecular Biology, and Nanotechnology, 2022
Many neurodegenerative diseases are complex and progressive, with a lack of clear mechanisms and effective treatment methods, as the differences between animal and human brain are wide and this remains one of the major challenges in animal-based models of human brain disease. Furthermore, animal-based models of neurodegenerative diseases are time consuming and resource intensive. However, iPSCs give us novel approaches to combating neuronal diseases. Many researchers have successfully developed induced pluripotent stem cell lines from patients with neurodegenerative diseases. (Alves et al., 2015) to study the etiology and mechanism of diseases. Neurogenesis has been found to occure in two neuronal niches in the adult brain, the subependymal zone lining the lateral ventricles and the subgranular zone of the dentate gyrus. This fascinating finding opened up the possibility of converting nonneurogenic astroglia into neurons when induced with an appropriate transcriptional factor (Alonso et al., 2012).
Transform Pain to Purpose
Published in Payal Nanjiani, Achieve Unstoppable Success in Any Economy, 2020
I had an opportunity to sit across the table and talk with Dr. Senthil Radhakrishnan, the Administrative Chief and Clinical Neurosurgical PA from the Department of Neurosurgery at Duke Hospital and a Guest Lecturer at the Duke PA Program. I asked him what happens to the brain when emotional pain builds up. He said emotional pain, if prolonged for more than three months, can manifest itself as chronic physical pain and can lead to depression. Emotional pain can mimic the effects of chronic pain and depression and cause structural changes in the brain, especially the areas responsible for memory, mood, and executive functions. This stress can interrupt neurotransmitters in the hippocampus and prevent formation of new neurons, thereby causing a shrinking of the hippocampus. Lack of new neurons impedes memory, learning, and dealing with those emotions, thus creating a vicious cycle. Brain MRIs of people dealing with chronic pain when compared to healthy individuals reveal a smaller hippocampus. The dentate gyrus of the hippocampus is crucial for learning and memory. On the other hand, the amygdala, the tight cluster of nuclei located deep in the brain on either side of the medial temporal lobe, is part of the limbic system and plays a vital role in processing emotion and memory—especially memories associated with fear, anxiety, and motivation. Persistent emotional pain causes hyperactivity in the amygdala and even hypertrophy of the amygdala. Hypertrophied amygdala can cause anxiety disorders and sleep disturbances. Finally, the prefrontal cortex, which is responsible for several functions including regulating emotions and decision making, may atrophy with persistent emotional pain and depression.
Nanovations in Neuromedicine for Shaping a Better Future
Published in Klaus D. Sattler, st Century Nanoscience – A Handbook, 2020
Jyotirekha Das, G. K. Rajanikant
Neuroregeneration was first revealed by Dr. Robert Sperry while performing an experiment on a frog’s split-brain research. This experiment proved the neuronal regeneration and rewiring neural circuits which bestowed Dr. Sperry with a Nobel Prize in 1981. Unlike humans, many other animals such as goldfish, lampreys, and salamanders possess this regeneration property. However, in humans, the neural stem cells obtained from specific brain areas (dentate gyrus, olfactory bulb, and cerebellum) and the spinal have shown regeneration property in vitro. The neurons actively generated from the sub-ventricular region migrated to the olfactory bulb to form interneurons. Conversely, those generated in the dentate gyrus add to memory formation in the hippocampus (Ming and Song 2005). Axon regeneration is another phenomenon which occurs upon axonal damage. It reconnects the neurons to restore functional loss following the damage; however, it is limited to native CNS’s inhibitory signals (Sandvig et al. 2004). These inhibitory signals are mainly generated by the glial cells (mostly astrocytes) of the CNS. The astrocytes inhibit neuronal regeneration by forming an impenetrable barrier accompanied with the cellular debris and myelin. Conversely, the Schwann cells play a major role in nerve regeneration by phagocytic infiltration and clearing the debris created by their CNS counterparts. This is aided by the physiological access to peripheral nerves involved the axons sprouting from a nearby node of Ranvier. These axons sprout extends to form new axons under the guidance of neurotrophins secreted by the Schwann cells and the extracellular matrix surrounding the axons prior to damage. This regeneration occurs at the rate of 2–5 mm/day, thereby restricting the natural healing if the gap exceeds 6 mm which will require surgical interventions (Schmidt and Leach 2003).
Reactive astrogliosis in the dentate gyrus of mice exposed to active volcanic environments
Published in Journal of Toxicology and Environmental Health, Part A, 2021
A. Navarro, M. García, A.S. Rodrigues, P.V. Garcia, R. Camarinho, Y. Segovia
Sofroniew and Vinters (2010) recognized the presence of reactive astrocytes in the hippocampus during inflammation. The dentate gyrus (DG), a region of hippocampal formation with a regular organization of its principal cell layers, is used as a model system for many facets of modern neurobiology (Amaral and Lavenex 2007) and further, it is the first region where all sensory modalities come together and play a critical role in learning and memory. This area seems markedly affected by volcanogenic pollutants since Navarro-Sempere et al. (2020) reported the existence of intracellular deposits of mercury in DG cells. Considering the characteristics of active volcanic environments, we hypothesize that chronic exposure to hydrothermal hazardous emissions could be a risk factor for brain neuroinflammatory processes and neurodegenerative diseases, associated with astrocyte proliferation and dysfunction. For that purpose, we have studied the hippocampal dentate gyrus of wild mice (used as surrogate species), since it is a vulnerable structure to neuroinflammatory processes and neurodegenerative diseases (Hedden and Gabrieli 2004; Small et al. 2002), such as Alzheimer’s disease (Li et al. 2008; Rodríguez et al. 2008) or Parkinson’s disease (Marxreiter, Regensburger, and Winkler 2013).
Curcumin offsets PTZ-induced epilepsy: involving inhibition of apoptosis, wnt/β-catenin, and autophagy pathways
Published in Egyptian Journal of Basic and Applied Sciences, 2020
Mona Hamdy, Ashraf Antar, Mohamed El-Mesery, Mohammed El-Shafey, Amr N. Ali, Khaled M. Abbas, Osama Ali. Abulseoud, Abdelaziz M. Hussein
Epilepsy is a common heath problem which influences approximately 50 million people worldwide and greatly impact the quality of life [1]. Also, about 0.5–2% of population has epilepsy which increases the socioeconomic burden in the world [2]. Normally, about 30% of the epileptic patients are refractory to the usual antiepileptic drugs and the seizure is not relieved even after accurate diagnosis and treatment [3]. Therefore, better understanding of the pathogenesis of epilepsy and epileptic fits helps us to explore new agents which manage the epileptic seizures of epilepsy It has been demonstrated that the hippocampus which consists of dentate gyrus (DG), cornu of ammonis (CA) regions (CA1, CA2, and CA3) is the generator of temporal lobe epilepsy (TLE) and surgical removal of the sclerotic hippocampus in patients with TLE often improves this epileptic condition [3]. Previous experimental studies found that the CA3 region of the hippocampus is the site of origin of discharge in TLE [4]. Moreover, the DG is considered as an obligatory pathway through which the impulses reach the hippocampus and are elaborated to regain access to the limbic cortices through the trisynaptic pathway [4]. The rat model of pentylenetetrazole (PTZ) kindling is similar to the human TLE which is characterized by atrophy, development of degenerative changes and loss of neurons in hippocampal regions especially CA3 region [5].
The effect of experimentally-induced diabetes on rat hippocampus and the potential neuroprotective effect of Cerebrolysin combined with insulin. A histological and immunohistochemical study
Published in Egyptian Journal of Basic and Applied Sciences, 2023
Doaa El-Adli, Salwa A. Gawish, Amany AbdElFattah Mohamed AbdElFattah, Mona Fm. Soliman
The hippocampus is a small organ located within the brain’s medial temporal lobe and forms an important part of the limbic system concerned with memory, emotions and behavior [5]. The hippocampal formation is subdivided into hippocampus proprius, dentate gyrus (DG) and subicular cortex. The hippocampus proprius is formed of five layers. It is divided into four regions (CA1–CA4) according to density, size and branching of axons and dendrites of the pyramidal cells in the pyramidal cell layer. The DG consists of three layers [6]. The granule cell layer (GCL) contains granule cells and immature neurons in the subgranular zone (SGZ) which is one of the stem cell-containing areas in adult mammalian brain [7,8].