Myofascial pain syndrome – fibromyalgia – is characterized by tender muscle points which tend to cluster in similar anatomical locations from patient-to-patient. Although the veracity of the condition has been questioned by neurologists, studies by J.D. Richardson, et.al., support a relationship of fibromyalgia to a clinical endocannabinoid deficiency, suggesting that the endocannabinoid system regulates the immunodeficiency system and modulates pain thresholds and its absence may underlie the hyperalgesic tender muscle points of this condition.7,8 These and subsequent studies have suggested that cannabinoid agonists would be useful in the treatment of chronic pain conditions such as myofascial pain syndrome, temporomandibular joint pain (TMJ) and reflex sympathetic dystrophy (RSD), a condition which can follow minor trauma, usually to an extremity and is often described as being worse than the original injury.
Irritable bowel syndrome (IBS) can be a recurring nightmare for patients and their physicians. It involves recurrent constipation and/or diarrhea, often associated with painful abdominal spasms and distention. Infection, diet and emotional stress can trigger an attack and the conditions represent the most common cause of referral to gastroenterologists. All of the current treatments are only partially effective. We have previously noted that CB2 receptors are commonly found in the gut and 2-arachidonylglycerol (2-AG) has been identified in dog intestine by Dr. Mechoulam and her associates to bind to these endogenous cannabinoid receptors.9
Pertwee, who has exhaustively studied the relationship of cannabinoids in gastrointestinal function, has demonstrated that mammalian enteric nervous systems contain CB1 receptors and stimulation depresses GI motility.10 These stimuli include delayed gastric emptying, decrease peptic acid production and slowed peristalsis. Furthermore, these effects are also mediated in the brain, confirming the old adage “the brain and gut speak the same language.” Confirming this, it has been shown that chronic intestinal inflammation results in the sensitization of cannabinoid receptors, to the extent that Izzo and DiCarlo suggested the use of cannabinoid drugs to treat IBS.11, 12 Given the above, it is not surprising that co-morbidities of these conditions should exist. Indeed, a high lifetime prevalence of migraine, IBS, depression and panic disorder were found among 33 women meeting the American College of Rheumatology criteria for figromyalgia.13
Autism Spectrum Disorder
The interaction of gastric and environmental factors appear to play a role in the genesis of the constellation of clinical entities known as Autism Spectrum Disorder (ASD). They are recognized by delayed and disordered social and communication skills and frequently with repetitive speech and behavior.
Success in treating ASD has been slow due to our poor understanding of its causes. This has resulted in the lack of a single standard approach to treatment. However, in 2008 Agudelo, Newton and associates discovered an immune system dysregulation in autistic children revealing an altered immune response in peripheral blood mononuclear cells (PBMC’s).14
As noted above, there are two known endogenous cannabinoid receptor subtypes: CB1, expressed primarily (but not exclusively) in the brain, and CB2 found primarily in peripheral somatic tissue and to a lesser extent, in the brain. The next exciting revelation came in April 2013, when Dr. Dario Siniscalo and his co-workers discovered that CB2 was significantly increased in the peripheral blood mononuclear cells (PBMCs) of autistic children compared to their age-related normal controls. Variations in cellular biochemical events in ASD have been identified, such as mitochondrial dysfunction, intestinal dysfunction, and immune dysregulation.15 Other immunological dysfunction in ASD demonstrated that PMBCs show increased levels of pro-inflammatory cytokines and interleukins that result in long-term immune system alterations.16
Recently Sinisscalco and co-workers demonstrated that PBMCs in ASD children show altered pleiomorphic enzymes (caspases) that regulate apoptosis and inflammatory signaling pathways. Caspases are pleiomorphic enzymes that function in cell proliferation and differentiation, as well as cellular activation and nuclear re-programming.17, 18