Choroid plexuses: anatomy, functions and pathologies

Cerebrospinal fluid is essential for the functioning and hygiene of the central nervous system, especially the brain. This substance occurs in the four structures we know as the “choroid plexuses”, located in the brain’s ventricles.

In this article we will describe the anatomy and main functions of the choroid plexuses. We will also mention the pathologies most frequently associated with these regions of the central nervous system.

    Anatomy of the choroid plexuses

    The choroid plexuses are located in the ventricular system of the brain; there is a plexus in each of the four ventricles. Its nucleus is made up of connective tissue, capillaries and lymphoid cells and is surrounded by a layer of epithelial cells. The production of cerebrospinal fluid depends on the epithelium, Main function of the choroid plexuses.

    In addition, this structure separates and links the central nervous system and the circulatory system, which explains the involvement of the choroid plexuses in the transport of nutrients and hormones to the brain and in the elimination of residual substances.

    The ventricles are four interconnected brain chambers. After being generated in the choroid plexuses, which are found in virtually all regions of the ventricular system, cerebrospinal fluid travels through the ventricles to the brain until it reaches the spinal cord.

    Functions of this structure

    The number of functions attributed to the choroidal plexuses has increased in recent years; they have not only been shown to be relevant to their ability to make cerebrospinal fluid and protect neurons, but they also play additional roles that could lead to therapeutic benefits as research progresses in the future.

    1. Production of cerebrospinal fluid

    Cerebrospinal fluid performs several key functions in the central nervous system: cushions the blows received by the brain and allows it to maintain its density, participates in immune defenses, regulates homeostasis (extracellular balance) and helps eliminate waste from the brain.

    2. Formation of the blood-brain barrier

    Choroid plexus epithelial tissue forms part of the blood-brain barrier, which separates blood and extracellular fluid from the central nervous system but allows the exchange of nutrients and wastes. It also has a defensive function, by preventing the entry of certain toxins.

    3. Maintenance of extracellular homeostasis

    The extracellular balance of the brain and spinal cord is maintained in part by the choroid plexuses, which modulate the interaction between the central nervous system and the immune system.

    4. Regeneration of tissues and neurons

    Choroidal plexuses secrete neuroprotective compounds that promote healing of neuronal damage; this effect has been mainly linked to traumatic injuries. Also in these structures some degree of neurogenesis has been detected (Production of new neurons from progenitor cells) even in adulthood.

      5. Detoxification of the brain

      The choroidal plexuses contribute to the detoxification of the brain in two ways: on the one hand the cerebrospinal fluid that they produce fulfills this function, and on the other hand its connection with the circulatory system facilitates the transfer of residual substances in the blood. to allow its elimination.

      6. Other functions

      In addition to the processes we have described, research has started in recent years on the role of the choroid plexuses in other functions: the

      , The production of nourishing polypeptides in neurons, the transfer of information to the sympathetic nervous system …

      Choroid plexus pathologies

      The choroid plexuses, and in particular the cerebrospinal fluid that they produce, fulfill fundamental functions for the organism, alterations in the anatomy and the functionality of these structures can promote the appearance of various pathologies.

      There are also a large number of factors that sometimes cause changes in the choroid plexuses. The relationship of these structures to Alzheimer’s disease, Strokes and head injuries are particularly relevant.

      In people with Alzheimer’s disease, atrophy occurs in the ependymal cells of the choroid plexuses; this leads to decreased production of cerebrospinal fluid, increased oxidative stress, and greater accumulation of toxins in the brain.

      On the other hand, and although it often does not have serious consequences, the appearance of cysts in the choroid plexuses during fetal development it can cause tumors and has been associated with aneuploidies (changes in the number of chromosomes in cells) such as Edwards syndrome, which is fatal in most babies.

      Bibliographical references:

      • Borlongan, CV, Skinner, SJM, Vasconcellos, A., Elliott, RB and Emerich, DF (2007). The choroid plexus: a new source of graft for neuronal transplantation. In Davis, CD & Sanberg, PR (Eds.), “Cell therapy, stem cells, and brain repair.” New York: Humana Press.
      • Emerich, DF, Vasconvellos, A., Elliott, RB, Skinner, SJM and Borlongan, CV (2004). The choroid plexus: function, pathology and therapeutic potential of its transplant. Expert Opinion on Biological Therapy, 4 (8): 1191-201.
      • Straziel, N. and Ghersi-Egea, JF (2000). Choroid plexus in the central nervous system: biology and pathophysiology. Journal of Neuropathology and Experimental Neurology, 59 (7): 561-74.

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