The Irony of Pericytes

Pericyte cartoon

It was another sleepless night for me. I wake, pray. Wake, read. Until it’s 5:00 am, and I tell myself it’s okay to be up. Will this be a good day or a bad day? Promising or not?

Kevin’s mission is to heal. Mine is to hope. This is how science helps. I tell myself that if something in our biology caused melanoma to occur, then something in our biology must cure it. There simply must be an answer – we just haven’t figured out the puzzle yet.

Sentinel nodes are not great messengers

Since the beginning of our fight against melanoma, I have expressed my doubts about melanoma metastasizing via lymph glands. Call it left over mother’s intuition, but I cringed at the thought of removing valuable, critical disease-fighting tools like lymph glands during the sentinel node seeking process, when Kevin’s scalp lesion was removed. It was nothing more than a hunch – but I felt melanoma (at least in his case) simply didn’t travel this way.

I was so certain of this (I don’t know why) I even argued with Kevin’s surgical oncologist that the efficacy of sentinel node removal, and tried to talk him out of it. I felt this procedure was still highly debatable in regard to preventing the spread of melanoma, and removing disease-fighting lymph glands seemed illogical. His candor and diplomacy were very kind – I often overstep my bounds as caretaker, much to Kevin’s chagrin (and anyone else’s in the room). However, to my surprise, the surgeon simply said, “You’re right. There’s no real evidence that this prevents metastasis when it comes to melanoma.”

However, thanks to medical protocol, the sentinel node biopsy and removal proceeded as planned anyway. As it turned out, Kevin’s nodes were clear, by the way. Please pardon me, but this angers me all the more as I recall sitting with him as he patiently and needlessly underwent the painful process of being injected in his head with dye for mapping the sentinel nodes.  Now evidence is actually pointing to sentinel node biopsy and removal contributing slightly to survival rates based upon the thickness of the melanoma, and whether its detected in the nodes. This can show the seriousness of the disease, but not where it spreads. That part is still a mystery. Affected nodes only point to where melanoma is, not where it will be.

Fast forward one year, and we’re looking at a brain and lung metastasis, subcutaneous lesions and widespread mets in soft tissue. How did this happen if the nodes were clear?

How does melanoma spread from a foot or scalp to all over, without detecting sentinel nodes? The answer could offer a potential cure – or at least where to go when a cure is discovered.

The Irony of Pericytes

Pericytes, ironically pronounced as “parasites” are cells which live along small blood vessels. While they are a healthy part of how our blood vessels, blood pressure and more functions, the irony is that the parasite of melanoma likely overtakes the pericyte – creating an efficient method of travel.

Discovered about 140 years ago by a French scientist, docs weren’t exactly sure what these cells did until recent years – and they’re still learning. As it turns out, melanoma seems to migrate via replacing and mimicing pericyte cells along blood vessels’ outer walls.

This fact explains two very critical things: why brain and blood-rich lungs are more prone to metastasis with melanoma, and also HOW distant metastasis is the norm rather than the exception when it comes to progressed melanoma.

One thing about pericytes – they are an integral cellular component of the blood-brain barrier, and work to promote tissue survival. This means they have a virtual “hall pass” when it comes to your brain.

Not everything is let in there – this could explain why brain mets are so common with melanoma.

The good news is, if you’re on a mission to get to the brain to stop or treat melanoma brain metastasis, following the path of pericytes could be the fastest highway to get there. Could this also explain why cannabis oil or other meds which are capable of passing through the blood/brain barrier can have a therapeutic effect?

Pericytes are tricky little suckers. Since the early 1900s it has been widely accepted that pericytes are responsible for blood flow, general blood pressure and the nutrition of vascular walls. They can affect everything from your vision, to Alzheimer’s to melanoma, kidney and pancreas function.

Light a plant, UV Light Accelerates Cancer Cells that live outside of blood vessels

Two researchers, a husband and wife team, Dr. Claire Lugassy, MD and Dr. Raymond Barnhill, MD at UCLA’s Jonsson Comprehensive Cancer Center, have discovered that melanoma cells “creep like tiny spiders” along the outside of blood vessels without ever entering the blood stream, and that this process is exacerbated by exposure to ultraviolet (UV) light.”

This process is called extravascular migratory metastasis (EVMM). While melanoma cells can travel via the bloodstream, they can also move along the outside of blood vessels, creating a fast track pathway which leads to metastasis. This happens when melanoma cells overtake or replace pericyte cells, which normally reside on the outside of blood vessels. Here they travel until they reach a blood-rich destination – this explains how melanoma can metastasize to distant sites, undetected. Oh – and your central nervous system? It’s rich with pericytes. Another reason melanoma may take the highway to the brain.

According to the research, mice with melanoma exposed to UV light experienced inflammation which increased the EVMM and lead to more lung metastasis than mice which were not exposed. UV light “provoked” the inflammation at the site of the tumor, which caused the mice’s immune systems to attract a type of white blood cell (neutrophils). The neutrophils promoted the travel of melanoma cells along the outside of blood vessel walls (angiotropism).

So, as melanoma cells ‘rode’ along the bloodstream being pushed along by white blood cells, the white blood cells didn’t recognize them as invasive – which is typical of cancer cells.

Do we need a cocktail?

Perhaps we need a cocktail – a terrific combination to clean things out, melanoma-wise?

If there is a way to hitch a ride with white blood cells (virotherapy), alert them to cancer and break down the cellular wall (sildenfenil or anti-PD-1) and pass the blood/brain barrier (cannabis oil) while reducing inflammation as a side effect, we might just have it?

Are things like high blood pressure a good indication that the pericytes are winning over bad things like melanoma? Are other problems like Alzheimer’s or Parkinson’s essentially the same thing as melanoma, but a different form due to a different genetic response but same pathway to the brain?

The more I read about side effects, the more I realize how interconnected our systems are. This makes the snake oils of the past much more logical. One slight change in something affects many. Perhaps as research continues and technology improves, the research of other diseases will shed greater light on more deadly ones.

One thought on “The Irony of Pericytes

  1. I was my son Jason’s caregiver. I want to tell you what you are doing will be worth millions of dollars, ( as if you could put a dollar amount on time spent with someone you love) so just keep on going. Pat OrtegA


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