Across two decades of teaching therapists how to interact with lymphatics through MLD and Lymph Taping, I have witnessed an explosion in research on lymphatic function and disease.
Some observed truths have been completely reversed,
like the advice around exercise for people affected by lymphedema. Once it was shown that any post-exercise swelling is temporary, and that overall people who exercise have better lymphedema outcomes than those who don't, our advice did a big 180 turn from don’t overload the limb, to move as much as you can.
There have also been reassuring moments when
new technologies revealed details supporting what we already know,
such as how the lymph obligatory load is drained from the brain, the presence of pre-lymphatic channels in loose connective tissue, and the sympatholytic effect of MLD.
Modern laboratory techniques now allow us to track the tiny molecular messaging that goes on at a phenomenal level in and around all our cells, and a wonderous new world of lymphatic endothelial cells (LEC), the inner working of lymph nodes, and the genetic mechanisms behind many lymphatic disorders, is opening up to us.
LECs respond to lymph flow, pathogens and proteins in the lymph.
When I first studied anatomy and physiology in the 80’s, endothelial cells made a slippery lining for the inside surface of blood and lymph vessels and didn't do much else. Since then, molecular biology has allowed us to peer into the intricate life of the lymphatic endothelial cells, revealing their vital role in maintaining lymph flow and other complex interactions in the cellular milieu [1]. We now know that LECs both influence and respond to lymph flow and are actively involved in formation of valves and regulation of lymphatic smooth muscle contraction. The composition of the lymph is monitored by the LEC which can initiate vasoconstriction of lymph vessels in an acute injury, or restrict the outflow from a lymph node if the lymph is carrying too much harmful material.
To remain healthy the LEC depend on a continuous, low-pressure flow of lymph passing over them and in lymph vessels exposed to long standing high protein oedema, the lymph vessels become fibrosed and cease pumping altogether, a vicious downward spiral once lymph flow is compromised.
It’s easy to see the role of MLD here.
When we actively stimulate the flow of lymph through the vessels during MLD, we help to preserve LEC health and lymphatic function. If applied in the immediate recovery period after surgery, radiotherapy or traumatic injury when lymph vessels have a small window of opportunity to repair, MLD promotes healing at both tissue and vessel level.
In many ways MLD is like an exercise class for the lymphatic smooth muscle.
The precise shearing forces applied during application of the Dr Vodder method stimulate stretch-receptor-reflex mediated lymphatic pumping. So the smooth muscles get a bit of a work out. This promotes lymph flow and as movements in the loose connective tissue simultaneously increase lymph formation, the cumulative effect is an increase in lymph flow.
Like all exercise this will preserve and even increase the capacity of the lymph angions to maintain lymph-motoricity, and is a good reason for people affected by lymphoedema and lipoedema to have regular MLD to keep their struggling lymph systems as healthy as possible. Read previous #TalkingLymph posts on LECs
References
Becker, J.; Schwoch, S.; Zelent, C.; Sitte, M.; Salinas, G.; Wilting, J. Transcriptome Analysis of Hypoxic Lymphatic Endothelial Cells Indicates Their Potential to Contribute to Extracellular Matrix Rearrangement. Cells 2021, 10, 1008.