“What Are the 78 Organs in the Human Body- List of Organs.” BYJUS, 2020, byjus.com/biology/what-are-the-78-organs-in-the-human-body/.

The secret lies in the meningeal lymphatic vessels, which connect the brain and the immune system. (FierceBiotech, 2018). These vessels help keep a healthy fluid balance in the brain and therefore could be a new treatment target for Alzheimer and dementia patients. (FierceBiotech, 2018).

For a long time, lymphatic vessels that carry fluid, waste and immune cells were thought to be absent from the mammalian central nervous system.

 But in 2015, a team led by neuroscientist Jonathan Kipinis discovered such a system in the brains of mice, and a National Institute's of health (NIH) team later extended the findings to people and monkeys. Now, Kipinis and several members of that team have returned to study the role of these vessels in aging and Alzheimer’s disease. (FierceBiotech, 2018).

They found that meningeal lymphatic vessels drain macromolecules like amyloid-beta from the CNS into the cervical lymph nodes in mice. (FierceBiotech, 2018).The scientists then experimentally damaged the cells that form these vessels, which led to the observed dramatic decline in brain-fluid flow. (FierceBiotech, 2018). What’s more, mice with ablated meningeal lymphatic vessels also showed an increased load of harmful amyloid-beta plaque, along with impairments in spatial learning and memory. (Fierce Biotech, 2018). They discovered that the proteins responsible for Alzheimer’s get drained through these lymphatic vessels in the brain along with other cellular debris, so any decrease in flow is going to affect this protein build-up and cause damage. (FierceBiotech, 2018). 

The effect of ageing on the brain’s of these mice were observed. 
In humans, ageing itself increases the risk of neurological disorders, including Alzheimer’s.  Old mice experienced increased brain drainage compared to young mice, and their meningeal lymphatic vessels were also narrower, scientists observed. (FierceBiotech, 2018). To see if they could fix this damage, researchers used a compound called vascular endothelial growth factor C (VEGF-C). (FierceBiotech, 2018). When they treated healthy aged mice with VEGF-C, they found that the animals' vessels grew larger and drained better, and they observed improved performance on learning and memory tasks. (FierceBiotech, 2018).

In their recent research, Kipinis and his team suggested that the efficacy of current therapies for Alzheimer’s might be improved by repairing aging-related decline in meningeal lymphatic drainage. (FierceBiotech, 2018). Modulation of meningeal lymphatic function in aged individuals might represent a novel preventive therapeutic strategy, not only to delay initiation and progression of Alzheimer’s disease but also for use against other damaged brain proteinopathies.(FierceBiotech, 2018).

The role that the meningeal lymphatics play in diseases of the nervous system is an area of active research, particularly for neurological disorders in which immunity is a fundamental player, such as: multiple sclerosis, Alzheimer's disease (AD), amyotrophic lateral sclerosis, Hennekam syndrome, and Prader-Willi syndrome. (Raper, Louveau, Kipinis, 2016). Impaired clearance of interstitial fluid (ISF) waste has been associated with accelerated accumulation of toxic amyloid beta, the main component of amyloid plaques in AD.(Raper, Louveau, Kipinis, 2016).

Rohma Shahab


References:
1.      FierceBiotech. (2018). Brain’s lymphatic system, just recently discovered, now linked to aging and Alzheimer’s. [online] Available at: https://www.fiercebiotech.com/research/brain-s-recently-discovered-lymphatic-system-linked-to-aging-and-alzheimer-s.

2.      Raper, D., Louveau, A. and Kipnis, J. (2016). How Do Meningeal Lymphatic Vessels Drain the CNS? Trends in Neurosciences, [online] 39(9), pp.581–586. doi:https://doi.org/10.1016/j.tins.2016.07.001.

3.      Da Mesquita, S., Fu, Z. and Kipnis, J. (2018). The Meningeal Lymphatic System: A New Player in Neurophysiology. Neuron, image [online] 100(2), pp.375–388. doi:https://doi.org/10.1016/j.neuron.2018.09.022.

 

Mesentery is an organ that connects the intestine to the rear abdominal wall of the human body. It assists in fat storage and enables blood vessels, lymph and nerves to supply the intestine. (Coffey and O’Leary, 2019). The Mesentery was ignored by humans for thousands of years, because in comparison with other organs, it is too fragmented. But after 2012, examinations with new microscopic instruments showed that it was a single structure. (Coffey, 2013).

 

The earliest description about the presence of mesentery is in the 15^th century, but people at that time didn’t realize that it was a human body organ. During the late 19^th and early 20^th century, the whole structure of the mesentery was identified. However, only at the beginning 21^st century, this structure was finally identified as an organ.(Coffey and O’Leary, 2019).

 

Leonardo da Vinci first described the presence of the mesentery first in his anatomical experiment, although he thought it was part of the intestine. Later, Carl Toldt and Frederick Treved identified this organ separately after studying it in many patients, but it was only J. Calvin Coffey who discovered it as a new organ instead of a component of another other organ some centuries later. (Coffey and O’Leary, 2019)(Alexander, 2017).

 

Graduate Entry Medical School, 4i Centre for Interventions in Infection, Inflammation and Immunity, University Hospital Limerick, University of Limerick, Limerick, Ireland. (Coffey and O’Leary, 2019).

 

In 1879, Austrian anatomist Carl Toldt describes the structure of mesentery in human body from childhood to adulthood. A few years later, Sir Frederick Treves made an  anatomical description about the mesentery (Treves, 1885) that was included in surgical and anatomical literature for centuries. However, these findings had been ignored by people until recently, when J. Calvin Coffey identified it as the 79^th organ in human body. (Alexander, 2017).

 

 

The discovery of the mesentery enables further scientific research, which helps to improve diagnosis of abdominal diseases and the development of pharmacology about those diseases. Moreover, this finding will also standardize abdominal surgery, a clear understanding of the mesentertry as a new organ provides an anatomical basis for high-quality resection of duodenum to rectum. For example, if the mesentery based strategy is used to guide the resection of Crohn's disease, the margin positive and re operation rate can be significantly reduced. (Coffey and O’Leary, 2019).

Shicheng Zhao

References:

Prof J Calvin Coffey FRCSI, D Peter O'Leary PhD (November 2016); “The mesentery: structure, function, and role in disease”; THELANCET Gastroenterology & Hepatology; 1, 3, Pages 238-247
Available at:
https://pubmed.ncbi.nlm.nih.gov/28404096/

Roberta Alexander (January, 2017), “Scientists Say They’ve Discovered ‘New’ Organ in Human Body”, Health News.
Available at:
https://www.healthline.com/health-news/new-organ-in-human-body#Whats-the-function?

Toldt C, AD Rosa (1879). "Bau und wachstumsveranterungen der gekrose des menschlischen darmkanales". Denkschrdmathnaturwissensch. 41: 1–56.
Available at:
https://www.scopus.com/record/display.uri?eid=2-s2.0-84857962433&origin=inward&txGid=573407b2145516faae95e975b415104d

Treves F (March 1885). "Lectures on the Anatomy of the Intestinal Canal and Peritoneum in Man". British Medical Journal. 1 (1264): 580–3.
Available at:
https://pubmed.ncbi.nlm.nih.gov/20751205/

Coffey, JC (August 2013). "Surgical anatomy and anatomic surgery - Clinical and scientific mutualism". The Surgeon. 11 (4): 177–82.
Available at:
https://pubmed.ncbi.nlm.nih.gov/23597667/

“The Mesentery - Function - Structure - Vasculature - TeachMeAnatomy.” Teachmeanatomy.info, 2018, teachmeanatomy.info/abdomen/viscera/mesentery/

Who discovered it: It is unclear who initially discovered the bone in 1875, however the study for the re-emergence of the bone is lead by Dr Michaels Berthaume in the department of Bioengineering from Imperial College London (Allen, 2019).  

Where was it discovered: Again it is unclear where exactly the fabella was initially found but currently the study is happening at Imperial College London c Journal of Anatomy and they have also published an analysis on 21,676 over 27 countries. 

How was it discovered: The discovery occurred through the analysis of 21,000 knees over 150 years as well as the study published by the Journal of Anatomy. (Imperial News, n.d.). 

Significance of the finding currently and in the future: In general the importance of sesamoid bones is they help reduce friction within tendons, scientists believe that the increase in human weight and population overtime is what caused the fabella to come back. The sesamoid bone may help relieve the pressure by providing extra support. Although this may be considered as a positive impact the fabella can cause more harm than good. By having the fabella you are more prone to fabella syndrome, peroneal nerve injury and fractures (Dodevski et al., 2012). Studies currently taking place are trying to find an exact reason for the re emergence of the fabella and it may become “ the appendix of the skeleton” according to Dr Berthaume (Imperial News, n.d.).

Anna Ashika Rajanayagam

References

 Mystery arthritis-linked knee bone three times more common than 100 years ago | Imperial News | Imperial College London. [online] Available at: https://www.imperial.ac.uk/news/190943/mystery-arthritis-linked-knee-bone-three-times/#:~:text=The%20earliest%20records%20they%20looked

Scientists discover a bone called the fabella is making a comeback. [online] Mail Online. Available at: https://www.dailymail.co.uk/sciencetech/article-6939907/Scientists-discover-pointless-knee-bone-called-fabella-making-comeback.html#

Dodevski, A., Lazarova-Tosovska, D., Zhivadinovik, J. and Lazareska, M. (2012). Clinical significance of the fabella. Rentgenologiya i Radiologiya, [online] 51(3), p.258. Available at: https://inis.iaea.org/search/searchsinglerecord.aspx?recordsFor=SingleRecord&RN=44042002

Brogan, Caroline. “Region, Age, and Sex Decide Who Gets Arthritis-Linked ‘Fabella’ Knee Bone | Imperial News | Imperial College London.” Imperial News, 2019, Available at: www.imperial.ac.uk/news/193475/region-decide-gets-arthritis-linked-fabella-knee/.

 The glands are hooked up to large draining ducts, indicating transportation of fluid from one place to another. (Wu, 2020).

 The significance of this discovery is that it has helped reduce side effects of radiation therapy, such as: trouble swallowing, speaking and eating. (October, 2020, n.d.). This is seen as before the tubarial glands were discovered, some patients were receiving radiation therapy that would target these glands. (Wu, 2020). This led to significant damage to these glands, where patients would suffer with symptoms such as chronic dry mouth and swallowing problems. (Wu, 2020). Through looking at the records of 700 prostate cancer patients it was found that those who received greater radiation in these areas, had greater side effects. (October, 2020, n.d.).

Tasnim Tareq

References:
October 2020, S.P.-L.S.C. 20 (n.d.). Scientists discover new organ in the throat. [online] livescience.com. Available at: https://www.livescience.com/new-salivary- gland.html.
 
The tubarial salivary glands: A potential new organ at risk for radiotherapy. (2020). Radiotherapy and Oncology. [online] doi:https://doi.org/10.1016/j.radonc.2020.09.034.

Wu, K.J. (2020). Doctors May Have Found Secretive New Organs in the Center of Your Head. The New York Times. [online] 21 Oct. Available at: https://www.nytimes.com/2020/10/19/health/saliva-glands-new-organs.html.

Prakash, Bhanu. “Researchers Discovered a New Organ in the Human Body I Tubarial Glands.” Www.youtube.com, 2020, youtu.be/W1lbil-sFWk

Shicheng Zhao

Anna Ashika Rajanayagam