Cannabis and the Kidneys
By Stacey Marie Kerr MD, Hawaiian Ethos Medical Director
Elegant, complex kidneys
In medical school we studied the physiology of the kidney. It was a struggle to understand the elegant and complex workings of this vital organ. There are so many essential microscopic parts to the kidney, and they all work together to cleanse the blood of toxins. And to regulate blood pressure. And to regulate the body’s pH, our acid-base balance. The list of functions seemed endless.
When a friend approached me about her chronic kidney disease, asking if cannabis could help minimize destruction, I revisited the function of these elegant organs with the endocannabinoid system (ECS) in mind. The two are intimately connected, and there is promise in utilizing the ECS to help maintain kidney health.
what do kidneys do?
The kidneys are the body’s natural blood filter.
Each kidney receives blood from the body at a rate of over one liter per minute. Every four to five minutes, the kidneys filter all the blood in the entire body. Blood is brought into the kidney by the renal artery, which branches into smaller and smaller vessels until they become tiny capillaries deep within the kidney.
Tiny blood capillaries intersect with tiny kidney tubules. This is where the blood is filtered, removing toxins while preserving the essential products the body needs. The fluid that carries waste out of the kidneys is turned into urine and sent to the bladder to be voided.
The whole system is elegant, complex, and crucial to life. Capillaries and tubules are fragile and easily harmed. If the kidneys are damaged, scarred, and replaced with fibrous tissue instead of functioning cells, the filtration of the blood cannot be achieved and toxins build up in the body.
Capillaries bring blood to the kidney tubules to be filtered. In the tubules, toxins are removed. Clean blood is returned through capillaries, while fluid with waste in it goes through the collecting duct to be turned into urine.
Kidneys and the endocannabinoid system (ECS)
How do cannabinoids interact with the kidneys?
Joseph Tam, PhD, published research he performed at the Hebrew University of Jerusalem on the role of the endocannabinoid system in kidney diseases. [1] He identified the location of cannabinoid receptors in the kidney. He was then able to see how phytocannabinoids interacted with those receptors and affected kidney health. Highlights from his findings include:
Receptors, both CB1 and CB2, are found throughout the kidney.
Activating CB1 receptors in the kidney contributes to kidney abnormalities and dysfunction. Therefore safely blocking CB1 receptors in the kidney could possibly lessen and delay damaging changes to kidney tissue.
In contrast to CB1 activation, activating CB2 receptors appeared to lessen kidney injury and promote tissue repair.
so what kind of cannabis might help?
Based on Tam’s research, we can extrapolate that the most beneficial cannabinoid treatment for those with kidney disease might be cannabinoids that antagonize (block) CB1 receptors while stimulating CB2 receptors.
THC activates CB1 receptors. CBD slightly activates CB1 receptors, while blocking activity at CB2 receptors. With current research findings, neither of these two cannabinoids would be directly helpful for patients with kidney damage.
However, research has shown that THCV activates CB2 receptors and decreases activity at CB1 receptors – exactly what may be needed for supporting kidneys challenged by chronic disease. It appears that THCV may be the cannabinoid to watch when it comes to kidney health.
Studies in the field of THCV and renal disease are greatly needed to follow up on the potential benefits revealed by Tam’s research.
The Big Picture
It is very true that controlling blood pressure is important in managing kidney disease. Increased pressure can be extremely damaging to already challenged capillaries and nephrons.
Managing blood sugars, avoiding obesity, quitting cigarettes and sticking to a regular exercise program are all recommended for those with kidney problems. Keeping track of medications and supplements to make sure they are safe for kidneys is important. But it appears that cannabinoids may also be allies.
There is much to learn about the endocannabinoid system and phytocannabinoids, and focused research on THCV and kidney disease may well lead to promising supportive therapies in renal disease.
So much attention has been given to the CB1 receptors, since they are the source of intoxication, but we are now realizing that CB2 receptors may be powerfully effective targets for needed therapies. Current research in this area shines light on yet another way our bodies can work with cannabis to enhance and support healthy balance and function.
In memory of Bill Richardson.
Sources:
1. Tam J; The emerging role of the endocannabinoid system in the pathogenesis and treatment of kidney diseases. J Basic Clin Physiol Pharmacol 2016; 27(3): 267–276v PMID: 26280171 DOI: 10.1515/jbcpp-2015-0055