The first question that pops up in our calculation is, “What exactly are Exosomes?”
Medically speaking the exact definition of Exosomes according to Théry C, Witwer KW, Aikawa E, Alcaraz MJ, Anderson JD, Andriantsitohaina R, et al. is,
Exosomes are not exclusive to tissues only. In fact, Exosomes and other such Endovascular contents have also been detected in other body fluids like blood, CSF, Peripheral Fluid and even Urine.
In case of external growth medium experiments, Exosomes have been seen to be released in vitro by the cultured cell within the medium itself. Ranging between 30 nanometers and 150 nanometers Exosomes are generally much smaller in size than other EVs.
In the last 30 yrs since its discovery and naming, Exosomes have become much more than just a mere extracellular filler. Researchers have proven its immense potential in bringing about changes in the healthcare system.
These nano vesicular particles are seen within the cell during normal and abnormal conditions like pathophysiological changes. They mainly function a biomolecular carrier of various cellular content from one cell to another.
Exosomes have shown characteristic traits during various functional changes of the body. This has given rise to the question as to whether Exosomes can be used for other purposes to benefit the human body.
Considered as cellular waste for ages together, it has been recently proven that Exosomes are not waste but a unique alternate way of discharging the debris from within the cell membrane. This enables the cell to maintain the homeostatic balance within itself automatically.
Besides playing an important role in waste disposal, Exosomes have been known to play a significant role as a transport medium between the cellular membranes of different cells. This intracellular communication helps in maintaining the smooth pathological and physiological condition of the cells.
In one of the recent studies involving cancer cells, a new observation has been noted. Metastatic condition promotes shedding of Exosomes which is a very odd occurrence. These Exosomes, in turn, is effectively modulating the deteriorating immune status of the body and thus stabilizing it.
Besides that, Angiogenesis and parenchymal tissue remodeling are also other two remotely odd changes that have been noticed. This entire Exosomal activity chart showcases a predisposed metastatic condition and promotes tumor formation progression.
Using Mass spectrum analysis type Proteomics and lipidomics, the proteomes and lipidomes of the Exosomes of metastatic cells are being tested and analyzed. Based on this knowledge understanding its release mechanism and controlling it to help in stopping metastasis process is being done.
The endomembrane on the cell is only particular to a mammalian class of Animal Kingdom. However, most of the mammalian cell membrane produces Intra-luminal Vesicles, but the exact mechanism of production is yet to be identified.
Up until recently, the various cells of the Immune system like the B cells, Mast Cells and Dendritic cells have been known to shed Exosomes periodically at a constant and regular gap.
Exosomes are used by the cells as transfer medium of various membranous proteins, and other luminal contents. Post fusing with the second cell, the fate of the Exosomes is not very clear. Whether it is engulfed and discharged as waste or it is used as a transfer medium again is not very clear.
As of now, the studies conducted on Exosomes have showcased a few certain functions that are unique to Exosomes alone.
1. Improves the immune response
2. They are the primary communicator intracellular product that activates the working mechanism of T lymphocytes.
3. They are an intracellular carrier of proteins and other contents.
4. The Exosomes that have been derived from Keratinocytes play an essential role in modulating skin pigmentation by controlling the synthesis of melanin
The critical function of Exosomes it to act as a carrier between cells. Essential proteins are transferred from a cell to another. In the case of the Nervous system, the cell to cell communication occurs through the Myelin sheath.
Studies have hypothetically stated that Exosomes play a vital role in the Central nervous system. Being a carrier vesicle, the Exosomes contain many essential bioactive proteins. This fact alone can have enormous effects concerning diseases of the brain like Parkinsonian, Alziemers, Prion Disease and Traumatic Encephalopathy among many more.
The Exosomes of the Nervous System, in particular, tend to have remnants of Cerebrospinal fluid and Peripheral fluid in them. The fluid remnants are both extremely integral to the functioning of the brain.
Since Exosomes are impenetrable during the transfer they sustain their form and internal content while crossing the Blood-Brain Barrier or better known as BBB, this functions exceptionally well as a protection for the disease-related molecules in the system.
These Exosomes, thus found in the CNS can be used as Biomarkers to study the pattern of disease development. However, more in-depth analysis and date are yet to be recorded and confirmed before practically approaching the theory.
Exosomes are much more intricate than we know as of yet. There is a lot to discover about these mysterious cellular content. However, besides the excellent studies that are delving into the role of Exosomes in the modulation of the Nervous System, there is another aspect that scientists are working on.
The carrier or messenger functionality of Exosomes has been the topic of discussion amidst many studies, researches and investigations. Trying to find an alternative drug delivery system using Exosomes successfully has been in talks for some time now.
The progress of all these studies and experiments are still in a hypothetical state or under test phase. The probability of utilizing Exosomes to its full potential is enormous, but we are yet to reach that final phase of discovery.
Jan 28, 2020