Cannabinoids in Gastrointestinal Disorders

The presence and function of CB2 receptors in central nervous system (CNS) neurons are controversial. We report the expression of CB2 receptor messenger RNA and protein localization on brainstem neurons. These functional CB2 receptors in the brainstem were activated by a CB2 receptor agonist, 2-arachidonoylglycerol, and by elevated endogenous levels of endocannabinoids, which also act at CB1 receptors. CB2 receptors represent an alternative site of action of endocannabinoids that opens the possibility of nonpsychotropic therapeutic interventions using enhanced endocannabinoid levels in localized brain areas.

Crohn's disease and ulcerative colitis, collectively known as inflammatory bowel disease (IBD), are characterized by chronic inflammation of the gastrointestinal tract (1). IBD has been associated with poor quality of life and extensive morbidity and often results in complications requiring hospitalizations and surgical procedures (2-4). Most previous studies of IBD have used administrative claims data or data collected from limited geographic areas to demonstrate increases in estimated prevalence of IBD within the United States (5,6). Few national prevalence estimates of IBD among adults based on large, nationally representative data sources exist, and those that do tend to be based on older data. For example, the most recent national study used 1999 National Health Interview Survey (NHIS) data and estimated that 1.8 million (0.9%) U.S. adults had IBD (7). To examine the prevalence of IBD among the civilian, noninstitutionalized U.S. adult population, data from the 2015 NHIS were analyzed. Overall, an estimated 3.1 million, or 1.3%, of U.S. adults have received a diagnosis of IBD. Within population subgroups, a higher prevalence of IBD was identified among adults aged ≥45 years, Hispanics, non-Hispanic whites, and adults with less than a high school level of education, not currently employed, born in the United States, living in poverty, or living in suburban areas. The use of a nationally representative data source such as the NHIS to estimate the prevalence of IBD overall and by population subgroups is important to understand the burden of IBD on the U.S. health care system.

Marijuana use in the age group prone to coronary artery disease is higher than it was in the past. Smoking marijuana is known to have hemodynamic consequences, including a dose-dependent increase in heart rate, supine hypertension, and postural hypotension; however, whether it can trigger the onset of myocardial infarction is unknown. In the Determinants of Myocardial Infarction Onset Study, we interviewed 3882 patients (1258 women) with acute myocardial infarction an average of 4 days after infarction onset. We used the case-crossover study design to compare the reported use of marijuana in the hour preceding symptoms of myocardial infarction onset to its expected frequency using self-matched control data. Of the 3882 patients, 124 (3.2%) reported smoking marijuana in the prior year, 37 within 24 hours and 9 within 1 hour of myocardial infarction symptoms. Compared with nonusers, marijuana users were more likely to be men (94% versus 67%, P<0.001), current cigarette smokers (68% versus 32%, P<0.001), and obese (43% versus 32%, P=0.008). They were less likely to have a history of angina (12% versus 25%, P<0.001) or hypertension (30% versus 44%, P=0.002). The risk of myocardial infarction onset was elevated 4.8 times over baseline (95% confidence interval, 2.4 to 9.5) in the 60 minutes after marijuana use. The elevated risk rapidly decreased thereafter. Smoking marijuana is a rare trigger of acute myocardial infarction. Understanding the mechanism through which marijuana causes infarction may provide insight into the triggering of myocardial infarction by this and other, more common stressors.