THC and alcohol together caused worse heart cell damage in older rat hearts | Research

The takeaway

THC dose-dependently impaired cardiac mitochondrial respiration, with effects nearly doubled in aged rat hearts and worsened further when combined with alcohol.

People interested in cannabis cardiovascular safety, particularly for older adults who also drink alcohol.

97.5% mitochondrial impairment in aged hearts vs. 75.6% in young

What the researchers found

THC impaired cardiac mitochondrial respiration in both young and old rats, but the effect was significantly worse in aged hearts (97.5% vs. 75.6% impairment at the same dose, with a lower IC50). Combining THC with ethanol enhanced the damage further, and aged hearts produced significantly more reactive oxygen species after THC exposure.

Why it matters

Older adults are an increasingly common cannabis user demographic, and many also consume alcohol. This study suggests aging hearts may be more vulnerable to THC-related mitochondrial damage, especially when alcohol is involved.

The numbers in context

Old rats: 97.5% mitochondrial respiration impairment vs. 75.6% in young at 2x10-5 M THC. IC50 in old: 0.7 vs. 1.3 x10-5 M in young. ROS production 46.6% higher in old vs. 17.9% in young after THC.

How the study worked

Isolated cardiac mitochondria from young (12-week) and old (90-week) rats were exposed to increasing doses of THC, ethanol, or their combination. Mitochondrial respiration and hydrogen peroxide production were measured.

What this study cannot tell us

In vitro study on isolated mitochondria, not whole hearts or living organisms. Concentrations may not reflect physiological levels. Rat cardiac tissue may respond differently than human tissue. Only acute exposure tested.

How to read the evidence

Preliminary in vitro study on isolated rat cardiac mitochondria. Provides mechanistic data but cannot predict clinical outcomes in human cannabis users.

When this study was published

Published in 2024 in the International Journal of Molecular Sciences.

The bigger picture

Cannabis use among older adults is rising faster than any other age group. Combined with the high prevalence of alcohol use among seniors, this finding about synergistic cardiac mitochondrial damage has relevance for clinical guidance about substance use in aging populations.

Questions still open

Do elderly cannabis users show clinical signs of cardiac mitochondrial dysfunction? Would lower, more realistic THC concentrations still show age-dependent effects? Does CBD have protective properties against these mitochondrial effects?

Common questions

Is cannabis more dangerous for older hearts?

In this lab study, isolated heart mitochondria from aged rats showed nearly double the damage from THC compared to young rat hearts, and produced more harmful reactive oxygen species. Whether this translates to clinical heart problems in older cannabis users is not yet known.

Does mixing cannabis and alcohol make it worse?

Yes, in this study. Combining THC with ethanol enhanced the damage to cardiac mitochondria beyond either substance alone, with the effect being most pronounced in aged heart tissue.

Read the original research

Cumulative Deleterious Effects of Tetrahydrocannabinoid (THC) and Ethanol on Mitochondrial Respiration and Reactive Oxygen Species Production Are Enhanced in Old Isolated Cardiac Mitochondria.

International journal of molecular sciences, 25(3)

View on PubMed ↗Publisher’s paper ↗

Citation

Charles, Anne-Laure; Charloux, Anne; Vogel, Thomas; Raul, Jean-Sébastien; Kindo, Michel; Wolff, Valérie; Geny, Bernard. (2024). Cumulative Deleterious Effects of Tetrahydrocannabinoid (THC) and Ethanol on Mitochondrial Respiration and Reactive Oxygen Species Production Are Enhanced in Old Isolated Cardiac Mitochondria.. International journal of molecular sciences, 25(3). https://doi.org/10.3390/ijms25031835