THC Could Inhibit Organ Rejection in Transplant Patients

“We are excited to demonstrate for the first time that cannabinoid receptors play an important role in the prolongation of rejection of a foreign graft by suppressing immune response in the recipient,” noted Mitzi Nagarkatti, Ph.D., from the University of South Carolina School of Medicine. “This opens up a new area of research that would lead to better approaches to prevent transplant rejection as well as to treat other inflammatory diseases.”

Abstract

Immune cells have been shown to express cannabinoid receptors and to produce endogenous ligands. Moreover, activation of cannabinoid receptors on immune cells has been shown to trigger potent immunosuppression. Despite such studies, the role of cannabinoids in transplantation, specifically to prevent allograft rejection, has not, to our knowledge, been investigated previously. In the current study, we tested the effect of THC on the suppression of HvGD as well as rejection of skin allografts. To this end, we studied HvGD by injecting H-2k splenocytes into H-2b mice and analyzing the immune response in the draining ingLNs. THC treatment significantly reduced T cell proliferation and activation in draining LNs of the recipient mice and decreased early stage rejection-indicator cytokines, including IL-2 and IFN-γ. THC treatment also increased the allogeneic skin graft survival. THC treatment in HvGD mice led to induction of MDSCs. Using MDSC depletion studies as well as adoptive transfer experiments, we found that THC-induced MDSCs were necessary for attenuation of HvGD. Additionally, using pharmacological inhibitors of CB1 and CB2 receptors and CB1 and CB2 knockout mice, we found that THC was working preferentially through CB1. Together, our research shows, for the first time to our knowledge, that targeting cannabinoid receptors may provide a novel treatment modality to attenuate HvGD and prevent allograft rejection.

Clinical Trials, Studies and Publications:

Δ9-Tetrahydrocannabinol attenuates allogeneic host-versus-graft response and delays skin graft rejection through activation of cannabinoid receptor 1 and induction of myeloid-derived suppressor cells

 

22-Year Long Study Finds Marijuana Has No Effect on Physical or Mental Health

A study published in the Psychology of Addictive Behaviors journal found no long-term health effects associated with marijuana use.

Researchers at the University of Pittsburgh Medical Center and Rutgers University began the study in the late 1980s, and used then-14 year old males drawn from Pittsburgh public schools. Four groups were tracked until 2009 and 2010, when the participants were 36 years old…The study found no statistical change in physical or mental health among any of the four groups between the beginning and end of the research period. Even without controlling for other factors, chronic users did not have a worse health prognosis than individuals in the other groups.

Abstract

Some evidence suggests that youth who use marijuana heavily during adolescence may be particularly prone to health problems in later adulthood (e.g., respiratory illnesses, psychotic symptoms). However, relatively few longitudinal studies have prospectively examined the long-term physical and mental health consequences associated with chronic adolescent marijuana use. The present study used data from a longitudinal sample of Black and White young men to determine whether different developmental patterns of marijuana use, assessed annually from early adolescence to the mid-20s, were associated with adverse physical (e.g., asthma, high blood pressure) and mental (e.g., psychosis, anxiety disorders) health outcomes in the mid-30s. Analyses also examined whether chronic marijuana use was more strongly associated with later health problems in Black men relative to White men. Findings from latent class growth curve analysis identified 4 distinct subgroups of marijuana users: early onset chronic users, late increasing users, adolescence-limited users, and low/nonusers. Results indicated that the 4 marijuana use trajectory groups were not significantly different in terms of their physical and mental health problems assessed in the mid-30s. The associations between marijuana group membership and later health problems did not vary significantly by race. Findings are discussed in the context of a larger body of work investigating the potential long-term health consequences of early onset chronic marijuana use, as well as the complications inherent in studying the possible link between marijuana use and health effects.

Clinical Trials, Studies and Publications:

Chronic Adolescent Marijuana Use as a Risk Factor for Physical and Mental Health Problems in Young Adult Men