Sickle Cell Anemia Pain and Inflammation
Cannabinoids have an analgesic effect and direct action on mast cells to reduce inflammation. These medicinal benefits make cannabis helpful in relieving symptoms of sick cell anemia.
Sickle cell anemia (SCA) is an inherited condition and lifelong disease. In those living with it, red blood cells (RBCs) become misshapen, rigid, sticky, and shaped like crescent moons. This is far from innocent. Their shape prevents effective oxygen circulation throughout the body. The buildup of these RBCs in smaller blood vessels potentially blocks or limits regular blood circulation. This results in recurrent unpredictable acute and chronic pain in adolescents and adults. While opioids like morphine are effective in pain management, there are side effects associated with long-term opioid use.
Per the results of a survey of 57 adults (29 men and 28 women) living with sickle cell disease (SCD) conducted by Yale University, 42% reported cannabis use within the past 2 years. One and a half years after SCD qualified for medical cannabis, 44 people requested certification. Of these, 42 were certified.
Among those who had at least one urine drug test:
- 10 people (18%) tested positive for cannabinoids only
- 7 people (12%) tested positive for cocaine and/or phencyclidine only
- 3 people (5%) tested positive for both cannabinoids and cocaine/phencyclidine
- 79% reported that cannabis allowed less use of pain medicine
- A majority endorsed cannabis for other medicinal reasons like anxiety, appetite, mood and sleep
Cannabinoids reduce an increased response to a painful stimulus (hyperalgesia) and protect the body from tissue damage caused when blood supply returns after a period of lack of oxygen (reperfusion injury). Moreover, cannabinoids may be useful as analgesics to treat severe pain in SCD. Morphine and cannabinoid receptor agonist CP 55,940 (cannabinoid that mimics the effect of naturally occurring THC) exhibited deep tissue pain-reducing effects in mice models of SCA (HbSS-BERK).
Mast Cell Activation
Activation of mast cells (a type of white blood cell) and neurogenic inflammation activate the sensory neurons (peripheral nociceptors) that send “possible threat” signals to the brain and spinal cord. Based on studies of sickle mice, mast cell activation causes the release of inflammatory cytokines and neuropeptides (both are small protein-like molecules for cell and neuronal signaling respectively), resulting in continued pain. Morphine activates mast cells; an additional side effect.
Cannabinoids reduce mast cell activation, inflammation, and neurogenic inflammation in mice models via both cannabinoid receptors CB1 and CB2. Consequently, these reductions coincide with pain reduction. Based on the observable traits and pain characteristics of SCA, treatment with specific CB1R (ACEA), CB2R (JWH-133) and cannabinoid (CP 55,940) agonists reduced deep hyperalgesia or mechanical and thermal (heat and cold) hyperalgesia. Therefore, targeting both CB1R and CB2R simultaneously may prove advantageous in treating the complex, mixed type of pain that typically occurs in SCA. According to a Canadian study, a single inhalation (25 mg) of cannabis three times a day reduced the intensity of pain, improved sleep and was well tolerated, suggesting the potential of smoked cannabis as a management therapy for chronic pain.
Clearly, cannabinoids improve the quality of life and reduce morbidity in people with SCA.