The lineage of rodent oligodendrocyte has been very well characterized in vitro studies. In fact, the oligodendrocyte formation is very crucial in embryogenesis as well as in the postnatal development of the individual. To be more specific, these cells are essential for myelinating neuronal axons in the central nervous system and thus allowing fast conduction of electric impulses along the neurve fibres. Oligodendrocyte death leads to demyelination process, a pathological feature of neurological disorders such as multiple sclerosis (MS), acute disseminated encephalomyelitis (ADEM) or extrapontine myelinolysis (EPM) (Love S., 2006).
Oligodendrocyte progenitors (OPCs) remyelinate damaged nerve fibres in the adult CNS. However, this
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OPCs and mature oligodendrocytes do not differ only by their marker expression, but also by their morphology. Immature OPCs have big oval cell bodies with unbranched fine processes growing circularly, whereas mature oligodendrocytes have small cell bodies with branched processes growing longitudinally along axons (Butt AM. and Ransom BR., 1993).
Initially, scientists thought that OPCs form homogeneous and consistent population of cells. However, a deeper look at this issue has proposed a new theory explaining that the composition of OPCs varies according to their function, gene expression, proliferation rates, electrical properties and differentiation ability (Chittajallu R. et al., 2004; Lin G. et al., 2009; Rivers LE. et al., 2008). For instance, NG2+ cells residing in the motor cortex and corpus callosum of the mouse differentiate only to oligodendrocyte lineage postnatally. However, OPCs present in the anterior piriform cortex can generate also pyramidal neurons (Clarke LE. et al., 2012; Guo F. et al., 2010).
Nevertheless, late pre-progenitor cells have similar properties as stem cells. We can culture NG2 positive cells present in the subventricular zone (SVZ) with the fetal calf serum (FCS), cytokines and basic fibroblast growth factor (bFGF) and convert them back to their stem cell state. We can then transdifferentiate these multipotent cells to other neural
The breakdown of the myelin sheath is caused from a mutation of the gene that makes the Adrenoleukodystrophy protein (ALDP). This ALD protein helps the body metabolize saturated very-long-chain fatty acids found in the serum and tissues of the central nervous system. The newly mutated gene no longer acts as a help aid to breaking down the long-chain fats. Therefore, the body starts accumulating an abnormal amount of fat in the nervous system, adrenal gland and testes that sets off an unusual response in the immune system; demyelination.
There are many different types of stem-cells which can be implanted in patients to regenerate or replace the damaged or abnormal cells caused by not only diseases like Parkinson's but also Alzheimer's and spinal cord injuries (2). A specific example in relation to Parkinson's is the harvesting of embryonic stem cells. These human embryonic stem cells can be transplanted into the brain to replace and create dopamine neurons. The controversy is in how one can obtain these stem cells. During fertilization, in humans, the embryo is hollow and contains cells that eventually develop into a fetus (1). Researchers have discovered, as recently as 1998, that the cells in the embryo contain all
Embryonic stem cells are found in human blastocysts (Marcovitz 17). A blastocyst is a very young embryo (just a few days old) that contains around 200 undifferentiated stem cells (Marcovitz 17). German Zoologist Valentin Hacker coined the term “stem cell” after he discovered them in a blastocyst of a crustacean (Marcovitz 18). Embryonic stem cells were collected for the first time in 1988 by Dr. James Thomson of University of Wisconsin and by Dr. John Gearheart of Johns Hopkins (Panno 76). These stem cells are unspecialized; they do not perform a specific function like cells such as muscle and nerve do (“Stem Cells”). They are also pluripotent, meaning they have the ability to divide and become specialized cells (“Stem Cells”). This is why stem cells hold so
Even though, we understand that T-cells have gone rogue and cause the damage to the myelin no one understands why the T-cells start to attack the myelin to begin with. However, there is interesting data that suggest that genetics, a person's environment, and possibly even a virus may play a role”(WebMD). These theories have yet to be proven and subsequently prevents a cure.
They have many processes which envelope neuronal synapses. Oligodendroglia instead have processes which envelope the axon of the associated nearby neuron itself to "insulate" them via the myelin sheath. To differentiate via light microscopy, you would look for the classic myelin sheath (which due to its high fat content can be stained for easily) to distinguish an oligodendrocyte from the many surrounding astrocytes. For electron microscopy, you can easily see the shape of the cells so you can then make distinctions based on how the processes are shaped and where they interact with
Multiple sclerosis is an autoimmune disease that majorly affects the brainand the spinal cord (A.D.A.M. Medical Encyclopedia, 1). The disease affects the central nervous system and thus causes limitations of individuals to carry out various activities. In multiple sclerosis, the myelin sheath that covers nerve cell axon is destroyed causing inflammation (MediResource Inc., 1). Destructionof the membrane leads to slowed conveyance of signals from the spinal cord to the brain, which as a result leads to reduced response to different stimuli. Inflammation of the nerve occurs mostly when the immune cells from the body attack the nervous system. The inflammation is not only limited to the spinal cord, but sometimes extends to
The damaged myelin degenerates and is engulfed by macrophages. When the affected nerves are examined under the microscope, the first abnormality to be seen is the migration of inflammatory cells and macrophages into the nerve. This is followed by destruction of the myelin. The destruction of myelin is caused by the phenomenon: molecular mimicry – where the antigen of the invading organism is similar to the antigens on the surface of the myelin sheath, then antibodies and inflammatory cells attack and damage the myelin. Inflammation and degeneration of the myelin causes leakage of proteins from the blood into the CSF, causing the increased CSF protein concentration that characterizes the disease. Also, the degenerate myelin particularly slows down the propagation of nerve impulses along your peripheral nerves; resulting in muscle weakness or paralysis. Fortunately, Schwann cells are not usually damaged; they are able to multiply and align themselves along the axon to form a new myelin sheath. This is an efficient and effective process, and full recovery can
Adult stem cells, like embryonic stem cells, have the ability to differentiate into several more specialized cell types, but the potential number of cell types is far smaller than that of an embryonic stem cell. Embryonic stem cells, by nature, eventually turn into every type of cell in the body, whereas adult stem cells will only turn into a few cell types. For example, a blood stem cell, one type of adult stem cell, will eventually turn into one of eight types of specialized blood cells (Jordan 116.3).
Opitz syndrome is a disease characterized by a defect along the ventral midline of the human body. Some of these abnormalities include a cleft lip, heart defects, wide-spaced eyes (hypertelerism), laryngeal cleft, agenesis of the corpus callosum, and hypospadias. An important irregularity in patients is the effect disrupted proteins have on the corpus colloseum. The corpus colloseum is a neuronal component that separates the two halves of the brain. This protein is imperative because it controls MID-1 or the midline. The MID-1 protein also forms homodimers, which associate with microtubules in the cytoplasm, especially during fetal development. Therefore, MID-1 is involved in formation of multiprotein structures, acting as anchor points to
While embryonic stem cells can restore and repair tissue, there also can be a risk when inducing them into
Stem cells are undifferentiated cells that have the potential to differentiate into specialized cells that make up various organs in our body. Intriguingly, if the stem cells are given the right conditions, they can divide, differentiate and self-organize to form an organ by itself. Organs formed in this manner are called organoids. Specifically, Organoids are structures resembling organs, generated from embryonic stem cells in a three-dimensional culture system similar to in vivo. However, these structures need to possess specific characteristics in order to be termed as organoids; must contain multiple cell types of the organ it models (organ specific), must exhibit some specific functions of that organ and the cells should be spastically organized to mimic the targeted organ. Organoids have the ability to recapitulate the organ by self organizing itself. Self-organizing is governed by the combination of sorting out and fate specification and also, due to a growing movement away from two-dimensional culture. Different organoids can be generated different organs. Although, the generation of 3D organoids is a relatively new concept, it holds the potential to make promising changes in the field of medicine.
Glial cells are the most numerous cells in the brain, outnumbering neurons nearly 3:1, although smaller and some lacking axonal and dendritic projections. Once thought to play a subpar role to neurons, glial cells are now recognized as responsible for much greater functions. There are many types of glial cells, including: oligodendrocytes, microglia, and astrocytes. Oligodendrocytes form the myelin sheath in the CNS, by wrapping themselves around the axons of neurons. Their PNS counterpart, Schwann cells, are also considered glial cells. This sheath insulates the axon and increases the speed of transmission, analogous to the coating on electrical wires. Microglia are considered to be “immune system-like”; removing viruses, fungi, and other wastes that are present. Astrocytes, however, are considered to be the most prominent. Their functions span throughout the brain, including, but not limited to: the synchronization of axonal transmission via G-protein-coupled receptors, blood flow regulation via the dilation of blood vessels, and the performance of reactive gliosis in conjunction with microglia. Both astrocytes and oligodendrocytes develop from neuroepithelial cells. Other types of glial cells include Radial glia, which direct immature neuron migration during development.
Increasing evidence supports an important role of oligodendrocytes and myelination in the pathogenesis of schizophrenia. Oligodendrocytes are the myelin-producing cells in the central nervous system. To test the myelination dysfunction hypothesis of schizophrenia, possible myelination dysfunction was evaluated in a phencyclidine (PCP)-induced neurodevelopmental model of schizophrenia. On postnatal day
Human embryonic stem cells (ESCs) are pluripotent cells isolated from blastocysts, and are highly useful in studying human development (Itzkovitz-Eldor et al., 2000 p. 88). Although the National Institute of Health states that “it is not known if iPSCs and embryonic stem cells differ in clinically significant ways”, iPSCs are already being used to achieve the same results as ESCs in some applications without the use of embryos, removing the ethical concern associated with ESCs (National Institutes of Health, 2009). ESCs are capable of differentiating into all cell types, and can be used as a source of differentiated cells. In the report by Itskovitz-Eldor et al., they discuss the induced differentiation of ESCs in suspension into embryoid bodies, including the three embryonic germ layers. The authors state that “the ability to induce formation of human embryoid bodies that contain cells of neuronal, hematopoietic and cardiac origins will be useful in studying early human embryonic development” (Itzkovitz-Eldor et al., 2000 p. 88).
Researchers used BrdU pulsing to identify the target cells they wanted to monitor for possible growth and change. In order to evaluate the effects of aspirin on oligodendroglia in vitro, multiple aspects were studied. Cultures of neural stem cells and OPC’s were taken, incubated, stained, and treated with varying doses of aspirin. Cells are analyzed under the electron microscope to see the effects aspirin may have on oligodendrocyte lineage and development, as well as OPC proliferation and differentiation. Specific stains are used as markers for the cells being targeted as well as the processes they may be undergoing, such as proliferation.