Tags: Medical Marijuana; THC; Inflammation; Wound Healing

 

Thumbnail: This review discusses the effects of THC on inflammation and wound healing. There have been a number of studies suggesting that THC (the main psychoactive compound found in cannabis) has the potential to reduce inflammation through various mechanisms, which may be relevant from a surgical perspective, as inflammation plays an important role in the early stages of wound healing.

 

The problem: Cannabis use has become one of the most widely used psychoactive substances in the US, and a number of studies have suggested that the main active compounds in it, delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD), play an anti-inflammatory and immunomodulatory role. Given the increased recreational and medicinal use of cannabis, it is important to understand the extent of these effects, as they could have beneficial or detrimental effects depending on the situation. For example, overly exuberant or prolonged inflammation can delay wound healing and contribute to scar formation, making this particularly relevant to recovery after surgery.

 

The study: This report reviews literature related to the effects of THC on inflammation, particularly as it relates to potential effects on wound healing. The authors discuss how this relationship may be relevant to recovery from surgery. The articles discussed include those based on both in vitro and in vivo studies, and discuss how these findings could potential impact wound healing in humans.

 

Main Points:

• In mouse studies, an injection of THC suppressed the activity of certain T cells, providing strong evidence that THC can down-regulate immune responses- which may be relevant to wound healing, as T cells help regulate the inflammatory phage of wound healing and cell regeneration

• Exposure to THC can down-regulate production of cytokines from lymphocytes- another method of immunosuppression

• Similar effects were seen in different types of cells, in response to combinations of CBD and THC- showing that exposure to THC or CBD singly might act than a combination of the two

• THC has been shown to reduce inflammation in colitis in rats- combination with CBD increased these effects

• THC and CBD appear to inhibit mitochondrial processes, which play a role in immune cell responses, but this only occurred at very high levels and may not be relevant to wound healing in people

• In cell culture, THC has been shown to reduce the proliferation of cell types associated with psoriasis

 

Conclusions: These studies show that cannabiniods (THC and CBD) play a role in down-regulating the inflammatory process. The effects can be seen with THC or CBD alone, or synergistically. This suggests that these compounds could have an impact on inhibiting wound healing.

 

Why this is a good study:

• This review includes a wide range of studies that look at different conditions and mechanisms for immunosuppression.

• This review includes studies in both cell culture and animal models

 

Why this isn’t a perfect study:

• None of these studies address the cumulative, or chronic effects of a lifetime of use, as is common with many who use cannabis for recreational and medicinal purposes.

• These studies may not be directly translatable to patient use, as many of the cannabis strains available today are not standardized, and often have different concentrations of cannabinoids, which could have important implications if patients use cannabis while healing.

• None of these studies were conducted in humans, so it more work needs to be done to determine the extent of these effects in clinical practice

• These studies do not address if or how these compounds may interact with other medications

 

What this study adds:

• This review suggests that there is enough evidence that surgeons may consider the potential impact of cannabis use when counseling patients about pre-operative instructions

• If these compounds are found to have significant impacts on surgical recovery, it may be prudent to screen for cannabis use in patient groups (like cancer patients) likely to be using medical marijuana

 

What it doesn’t:

• This review does not find any studies with conclusive results that look directly look at these effects in humans- these studies are all in cell culture or animal models

• This review does not tell us what concentrations of THC or CBD might be have clinical relevance in suppressing wound healing

 

Funder:  None stated

 

Author conflicts:  None