An update of lymphatics and the Central Nervous System.
I am taking a break this month from my blog series on the therapeutic value of music in healing, and, instead, want to share with you some fascinating findings related to the Central Nervous System (CNS) and the field of lymphatic therapies.
The lymphatic system in the CNS – some research findings in the past decade (2011-2021)
Over the past decade, research into the central nervous system as regards its lymphatic drainage has shown that the accepted model (i.e., that there is no classical lymphatic drainage system in the central nervous system) needs to change.
We now know that the central nervous system undergoes constant immune surveillance (via the meninges) – but how the immune cells travel into and out of the CNS is an area that needs more research. Functional lymphatic vessels have been found (in the dural sinuses), which provide a pathway for passage of both fluid and immune cells from the CSF to deep cervical lymph nodes. Structurally, these vessels have the same molecular hallmarks of lymphatic endothelial cells.
It has been postulated that because these vessels have in the past been difficult to access, this has led to the commonly held view that the central nervous system does not have a lymphatic vasculature. Thus, looking towards the future, we may be able to change and challenge assumptions that have been made in the field of neuroimmunology, especially the causes of both neuroinflammatory (e.g., multiple sclerosis – MS) and neurodegenerative (e.g., Alzheimer’s and Parkinson’s) diseases.
Just looking at the titles of published research in the last decade indicates that this is an area of ongoing interest and research in the fields of neurology, neuroimmunology, neuroanatomy, neuroscience, neuropharmacology, immunology and lymphology to name a few. I have listed some of these titles as an indication of the direction research is taking in these fields. As can be seen, the following have all been published after 2014:
- Implications of the discovery of brain lymphatic pathways – Iliff JJ, Goldman SA, Nedergaard M.
- Lymphatic vessels of the dura mater: a new discovery? – Bucchieri F, Farina F, Zummo G, Cappello F.
- A.VEGF-C-driven lymphatic drainage enables immunosurveillance of brain tumours – Song E, Mao T, Dong H, Boisserand LSB, Antila S, Bosenberg M, Alitalo K, Thomas JL, Iwasaki
- How do meningeal lymphatic vessels drain the CSF? Raper D, Louveau A, Kipnis J.
- CNS lymphatic drainage and neuroinflammation are regulated by meningeal lymphatic vasculature – Louveau A, Herz J, Alme MN, Salvador AF, Dong MQ, Viar KE, Herod SG, Knopp J, Setliff JC, Lupi AL, Da Mesquita S, Frost EL, Gaultier A, Harris TH, Cao R, Hu S, Lukens JR, Smirnov I, Overall CC, Oliver G, Kipnis J.
So, how does this impact us as allied health professionals with a) a special area of interest being Manual Lymph Drainage (MLD), and b) those of us that have trained in the speciality of Lymphoedema management? In my opinion, this rising interest in the lymphatic system with respect to what it is, how it functions, what happens when the system is disturbed/damaged, and how Manual Lymph Drainage (MLD) can help mitigate the consequences of this disturbance/damage is long overdue.
The consequences of this interest mean that a) new surgical techniques have been developed – For example lymph node transfers, lymphatic-venous anastomoses, and “lymph-sparing” techniques and, using the sentinel lymph node biopsy to help prevent unnecessary excision of lymph nodes during surgery for breast cancer. b) new diagnostic tools have been developed, such as using indocyanine green (ICG) lymphography for imaging the lymphatics.
In both of these categories, the understanding of the importance of having a well-functioning lymphatic system comes to the fore – and, conversely, the chronic consequences of damaging this system, is now something that is being researched and talked about much more than in the past, wherein general little attention was paid to the lymphatic system. The emphasis always (and often exclusively) being placed on the cardiovascular system.
In my discussions with medical doctors and physiotherapists, very little time during all the years of training was spent on the lymphatic system and how to treat patients with problems in this system.
To highlight the very important role of the lymphatic system, I had wanted to give a talk called, “Without this system, you would swell up and die” – but had to choose a less confronting title. However, the truth is that you would swell up and die, if you did not have a lymphatic system. It is linked and integrated with both the cardiovascular and immune systems in the body, and ensures that excess fluid in the interstitial spaces is not left there, to stagnate and cause oedema, but rather is helped to be returned to the bloodstream via the vessels and nodes. This happens when the thoracic and right lymphatic ducts, which carry lymphatic fluid from the entire body, (except the head and neck) join the junctures of the internal jugular veins with the left and right subclavian veins.
To get back to the beginning of this article, indicating that the importance of research of the lymphatic system is being realised, let me end off with directing you to this article: Craniocervical manual lymph drainage and its impact on intracranial pressure – a pilot study by C Roth, H Stitz, C Roth, A Ferbert, W Deinsberger.
Although more research needs to be done in this field, the data showed that there was a “significant reduction of ICP (intracranial pressure) during therapy with craniocervical MLD in patients with severe cerebral diseases”
This bodes well for the expansion of the large variety of conditions that could potentially be treated with MLD, in the future, once more clinically qualitative investigations on patients with severe cerebral diseases have been done.
On a personal note, it has been fascinating to have started out as a certified massage therapist, then moved over into lymphatic therapies dealing mainly with pre-and post-operative MLD, then expanding my education by becoming a lymphoedema therapist, and starting to treat patients referred by oncologists, vascular surgeons, plastic and reconstructive surgeons, orthopaedic surgeons, dermatologists, physicians, rheumatologists, physiotherapists and others. And now looking towards a future where Manual Lymph Drainage may also be able to be used on patients with neurological conditions and diseases. I am certainly buoyed up by the potential scope of MLD in the future, and how many more patients and categories of patients will be able to be helped.
For more information on my clinical practice and teaching, please feel free to visit my site.