Written by: Mayukha Kashyap
A new study explores the use of cannabis on patients suffering from pain associated with sickle cell anemia.
Picture Source: https://www.mayoclinic.org/diseases-conditions/sickle-cell-anemia/symptoms-causes/syc-20355876
Sickle cell anemia is caused by a single gene mutation, where the codon GAG changes to GUG, causing the amino acid sequence to change from Glu to Val, thus changing the protein it is synthesizing. It is typically inherited and caused when there are not enough healthy blood cells present to carry oxygen to the blood and body. Unlike regular red blood cells, which are donut-shaped, sickle cell affected red blood cells are crescent moon-shaped, making it harder for the red blood cells to move freely through the blood vessels. The shape of the sickle cell affected red blood cells also causes a lot of pain for those suffering from it. The pain occurs when the sickle cells get stuck in smaller blood vessels, obstructing blood flow and oxygen to the body—those suffering from sickle cell anemia state that their pain is concentrated in areas surrounding their joints.
Genetically speaking, sickle cell anemia has some interesting characteristics. It is a recessive disease for starters, meaning that to have sickle cell anemia, one needs to have a recessive allele from each parent. However, one can still be a carrier for the disease if they have one dominant and one recessive allele from their parents. A person who is a carrier for sickle cell anemia does not have the disease but can give the disease to their offspring as they have one recessive allele for it. A punnet square is shown below to explain this further.
As seen in the punnet square, if both the parents are carriers of sickle cell anemia, they have the alleles S, the dominant allele, and s, the recessive allele. When figuring out the probability of their offspring having sickle cell, there is a 25% chance they are sickle cell free (SS), a 50% chance they are a carrier (Ss), and a 25% chance that they have the disease (ss). To put this in perspective, if the parents were to have four children, there is the chance that one of their kids would have sickle cell anemia, even though both parents do not have it.
Interestingly, carriers of sickle cell anemia in areas where malaria is common seem to be immune. Studies show that people living in areas with a high concentration of malaria are heterozygous, meaning they carry both the dominant and recessive allele for sickle cell anemia. In other words, they are carriers of the disease. Because they are carriers, they have enough healthy red blood cells to avoid any sickle cell pain. They also have some sickle-cell-shaped red blood cells resistant to the malaria parasite. When both the dominant and recessive alleles are beneficial, as seen in this case, it is called a heterozygous advantage.
So why does all this matter? A new study led by Kalpna Gupta of UC Irvine and Dr. Donald Abrams of UC San Francisco shows that cannabis can be used as a potential treatment for the pain associated with sickle cell. Research shows that vaporized cannabis may be more effective than opioids, the current treatment plan. After opioid-related deaths started spiking, doctors began prescribing them less, leaving fewer sickle cell patients options. In Gupta and Abrams’ study, twenty-three patients with sickle cell-related pain inhaled vaporized cannabis or a vaporized placebo for a five-day session. Researchers observed the patients’ pain levels through the testing period and found that cannabis increased its effectiveness over time. Patients stated that the pain interfered less with their daily activities, including walking and sleeping, and reported that their pain affected their mood less. However, despite pain levels being lower in patients given cannabis than the placebo, it was not statistically significant. Thus Gupta and Abrams maintain that more research needs to be done before conclusively stating that cannabis is more effective than opioids in terms of pain.
Using drugs such as cannabis or opioids, which are typically given a negative connotation, as a treatment option still draws criticism from scientists and users alike. The FDA has only approved it to treat two rare and severe forms of epilepsy, Dravet syndrome and Lennox-Gastaut syndrome. The U.S. Drug Enforcement Administration (DEA) puts cannabis in the Schedule I drug category with LSD and heroin because they are more likely to be abused than used for medical help. More research has not been done on the use of medical cannabis for this reason. However, they agreed to support researchers if they wanted to explore cannabis’s medical properties. For people such as Gupta and Abrams, doing more extensive studies with more people would give them a better picture of cannabis and its effects on sickle cell patients. Until then, patients need to sit tight and pursue other options.
Sources:
BioNinja. Sickle Cell Versus Malaria. Bioninja.
https://ib.bioninja.com.au/standard-level/topic-3-genetics/31-genes/sickle-cell-versus-malari
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Donald I. Abrams, Paul Couey, Niharika Dixit, Varun Sagi, Ward Hagar, Elliott Vichinsky,
Mary Ellen Kelly, John E. Connett, Kalpna Gupta. Effect of Inhaled Cannabis for Pain in
Adults With Sickle Cell Disease. JAMA Network Open, 2020; 3 (7): e2010874 DOI:
10.1001/jamanetworkopen.2020.10874
Mayo Clinic. “Sickle cell anemia.” Mayo Clinic, Mayo Foundation for Medical Education and
Research, 30 Jan. 2020,
https://www.mayoclinic.org/diseases-conditions/sickle-cell-anemia/symptoms-causes/syc-20355876
Ratini, Melinda. “Medical Marijuana FAQ.” WebMD, WebMD, 20 Aug. 2020,
www.webmd.com/a-to-z-guides/medical-marijuana-faq.
University of California - Irvine. "Cannabis shows potential for mitigating sickle cell disease
pain." ScienceDaily. ScienceDaily, 17 July 2020.
www.sciencedaily.com/releases/2020/07/200717133236.htm.
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