[Cannabis and lung. What we know and everything we don't know yet]

[Diffuse alveolar hemorrhage in cannabis smokers. A systematic literature review]

Cannabis is the most widely used illicit psychoactive substance in France. It can be responsible for numerous pulmonary complications, including diffuse alveolar hemorrhage (DAH). The objective of this systematic review of the literature was to present data concerning the relationship between cannabis smoking and DAH, which has rarely been reported in the literature. The review was based on a Medline search covering the 1980-2022 period and utilizing data drawn from 10 articles. DAH diagnosis is based on an association of hemoptysis, anemia and diffuse alveolar opacities on chest radiography with siderophages in the Bronchoalveolar Lavage Fluid (BAL). The 11 patients identified in this review were daily or regular cannabis smokers; in 4 cases they presented recent or recurrent hemoptysis with anemia; imaging revealed diffuse alveolar opacities in 10 of them, while BAL endoscopy highlighted a diffuse hemorrhage in the bronchial tree, and siderophages were observed in 6 cases. While evolution was favorable when cannabis consumption was discontinued, resumption occasioned DAH recurrence, and one patient died. Advice to quit should systematically be accompanied by addictological follow-up.

Modulation of pulmonary immune function by inhaled cannabis products and consequences for lung disease

The lungs, in addition to participating in gas exchange, represent the first line of defense against inhaled pathogens and respiratory toxicants. Cells lining the airways and alveoli include epithelial cells and alveolar macrophages, the latter being resident innate immune cells important in surfactant recycling, protection against bacterial invasion and modulation of lung immune homeostasis. Environmental exposure to toxicants found in cigarette smoke, air pollution and cannabis can alter the number and function of immune cells in the lungs. Cannabis (marijuana) is a plant-derived product that is typically inhaled in the form of smoke from a joint. However, alternative delivery methods such as vaping, which heats the plant without combustion, are becoming more common. Cannabis use has increased in recent years, coinciding with more countries legalizing cannabis for both recreational and medicinal purposes. Cannabis may have numerous health benefits owing to the presence of cannabinoids that dampen immune function and therefore tame inflammation that is associated with chronic diseases such as arthritis. The health effects that could come with cannabis use remain poorly understood, particularly inhaled cannabis products that may directly impact the pulmonary immune system. Herein, we first describe the bioactive phytochemicals present in cannabis, with an emphasis on cannabinoids and their ability to interact with the endocannabinoid system. We also review the current state-of-knowledge as to how inhaled cannabis/cannabinoids can shape immune response in the lungs and discuss the potential consequences of altered pulmonary immunity. Overall, more research is needed to understand how cannabis inhalation shapes the pulmonary immune response to balance physiological and beneficial responses with potential deleterious consequences on the lungs.

Standardized Cannabis Smoke Extract Induces Inflammation in Human Lung Fibroblasts

Cannabis (marijuana) is the most commonly used illicit product in the world and is the second most smoked plant after tobacco. There has been a rapid increase in the number of countries legalizing cannabis for both recreational and medicinal purposes. Smoking cannabis in the form of a joint is the most common mode of cannabis consumption. Combustion of cannabis smoke generates many of the same chemicals as tobacco smoke. Although the impact of tobacco smoke on respiratory health is well-known, the consequence of cannabis smoke on the respiratory system and, in particular, the inflammatory response is unclear. Besides the combustion products present in cannabis smoke, cannabis also contains cannabinoids including Δ9-tetrahydrocannabinol (Δ9-THC) and cannabidiol (CBD). These compounds are hydrophobic and not present in aqueous solutions. In order to understand the impact of cannabis smoke on pathological mechanisms associated with adverse respiratory outcomes, the development of in vitro surrogates of cannabis smoke exposure is needed. Therefore, we developed a standardized protocol for the generation of cannabis smoke extract (CaSE) to investigate its effect on cellular mechanisms in vitro. First, we determined the concentration of Δ9-THC, one of the major cannabinoids, by ELISA and found that addition of methanol to the cell culture media during generation of the aqueous smoke extract significantly increased the amount of Δ9-THC. We also observed by LC-MS/MS that CaSE preparation with methanol contains CBD. Using a functional assay in cells for CB1 receptors, the major target of cannabinoids, we found that this CaSE contains Δ9-THC which activates CB1 receptors. Finally, this standardized preparation of CaSE induces an inflammatory response in human lung fibroblasts. This study provides an optimized protocol for aqueous CaSE preparation containing biologically active cannabinoids that can be used for in vitro experimentation of cannabis smoke and its potential impact on various indices of pulmonary health.

Atteintes pulmonaires liées au cannabis inhalé

La relation entre cannabis et pathologies pulmonaires est difficile à établir : le cannabis est souvent fumé-mélangé à du tabac (« joint ») et les fumeurs de cannabis fument souvent aussi des cigarettes de tabac.

L’usage régulier de cannabis est un facteur de risque de bronchite chronique.

Il n’y a pas d’association significative entre inhalation de fumée de cannabis et obstruction bronchique, typique de la BPCO.

L’usage de cannabis peut augmenter le risque de sifflements thoraciques et/ou de développement d’un asthme.

L’usage régulier de cannabis est un facteur de risque de pneumopathies infectieuses, avec un risque plus élevé chez les sujets immunodéprimés et notamment les patients infectés par le VIH.

Les résultats des études épidémiologiques sur le risque de cancer bronchique chez les fumeurs de cannabis sont discordants.

Des cas de pneumothorax, pneumomédiastin, pneumopéricarde et pneumorachis ont été décrits chez les fumeurs de cannabis.

Les études épidémiologiques ne montrent pas d’association entre usage de cannabis et emphysème pulmonaire.

Les cannabinoïdes de synthèse, plus récemment introduits sur le marché, ont une toxicité importante. Ils peuvent provoquer des pneumopathies sévères et/ou une dépression respiratoire sévère.

[Asthma and cannabis, cocaine or heroin use]

INTRODUCTION

The use of cannabis, cocaine or heroin can be responsible for many respiratory complications including asthma.

OBJECTIVES

The aim of this systematic literature review of data was to expose the relations between cannabis, cocaine or heroin use and asthma.

RESULTS

Cannabis, cocaine or heroin use by inhalation may be responsible for respiratory symptoms (cough, wheezing), asthma onset, acute asthma exacerbations (which may require intubation and invasive ventilation) or deaths related to asthma. Lower adherence to asthma treatment is also observed. Cannabis induces a rapid bronchodilator effect. In contrast, its chronic use may induce a decrease in specific airway conductance. Studies on forced expiratory volume in one second (FEV1) reduction or decline are discordant.

CONCLUSION

Cannabis, cocaine or heroin use must be considered in cases of acute respiratory symptoms or asthma exacerbation in young persons and practitioners must help illicit substance users to stop their consumption.

[Cannabis: Similarities and differences with tobacco]

Nicotine is the specific psychoactive substance of tobacco while tetrahydrocannabinol (THC) is the specific component of cannabis. The inhalation technique of cannabis is different from that of tobacco smoking: the volume of puffs is larger, inhalation is deeper, and pulmonary retention time is longer. Cannabis addiction is difficult to evaluate, both products often being smoked concomitantly. The principle physical side effects of cannabis affect organs and functions in a similar way to tobacco: pulmonary, cardiovascular, endocrine and stomatological. Gastrointestinal complications such as cannabinoid hyperemesis are specific to cannabis. Some psychological effects of THC may be acute (altered time and space perception, sensory disability, decreased vigilance, mood and dissociative disorders, hallucinations and delirium, impaired learning and memory, impaired cognitive and motor performance, panic attacks and anxiety) or chronic (lack of motivation, disorganisation of thoughts, increase in frequency and severity of schizophrenic crises). Cannabis can also be implicated in traffic and workplace accidents. Synthetic cannabinoids have increased psychotropic and somatic effects due to a greater affinity for brain cannabinoid receptors.

[Acute eosinophilic pneumonia and illicit psychoactive substance use]

Illicit psychoactive substance (IPAS) use can lead to a number of respiratory complications, including acute eosinophilic pneumonia (AEP). Systematic literature review of data on AEP in IPAS users (cannabis, cocaine, heroin and amphetamine). Of two cases of cannabis and tobacco users reported to have developed AEP, one, a teenage15 year old boy presented with acute respiratory distress syndrome (ARSD) which necessitated extracorporeal membrane oxygenation (ECMO). Five cases of AEP in cocaine smokers (crack) are reported, one of which was fatal. The patient presented with acute pulmonary edema and ARDS which progressed to ventricular fibrillation and asystole. A 24-year-old woman presented with AEP after repeated inhalation of heroin. Finally, a case of an amphetamine abuser who developed AEP and ARDS after amphetamine inhalation is reported. The time between the first IPAS use and admission in cases reported ranged from 7 days to 4 years, while time between the last IPAS use and admission was short (less than 15 days). IPAS use must be sought in case of AEP, especially in young adults, and practitioners must advise and help users to stop their consumption.

Lung alveolar tissue destruction and protein citrullination in diesel exhaust-exposed mouse lungs

Humanity faces an increasing impact of air pollution worldwide, including threats to human health. Air pollutants prompt and promote chronic inflammation, tumourigenesis, autoimmune and other destructive processes in the human body. Post-translational modification of proteins, for example citrullination, results from damaging attacks of pollutants, including smoking, air pollution and others, rendering host tissues immunogenic. Citrullinated proteins and citrullinating enzymes, deiminases, are more prevalent in patients with COPD and correlate with ongoing inflammation and oxidative stress. In this study, we installed an in-house-designed diesel exhaust delivery and cannabidiol vaporization system where mice were exposed to relevant, urban traffic-related levels of diesel exhaust for 14 days and assessed integrity of alveolar tissue, gene expression shifts and changes in protein content in the lungs and other tissues of exposed mice. Systemic presence of modified proteins was also tested. The protective effect of phytocannabinoids was investigated as well. Data obtained in our study show subacute effects of diesel exhaust on mouse lung integrity and protein content. Emphysematous changes are documented in exposed mouse lungs. In parallel, increased levels of citrulline were detected in the alveolar lung tissue and peripheral blood of exposed mice. Pre-treatment with vaporized cannabidiol ameliorated some damaging effects. Results reported hereby provide new insights into subacute lung tissue changes that follow diesel exhaust exposure and suggest possible dietary and/or other therapeutic interventions for maintaining lung health and healthy ageing.

[Spontaneous pneumothorax and lung emphysema in cannabis users]

INTRODUCTION

If pulmonary complications of tobacco smoking are well documented, those associated with cannabis use are less known.

OBJECTIVES

Systematic literature review of data on pneumothorax and lung emphysema in cannabis users.

DOCUMENTARY SOURCES

Medline, on the period 1980-2018 with the following keywords cannabis or marijuana and pneumothorax or emphysema, limits "title/abstract". Among 97 articles, 42 abstracts have given use to a dual reading to select 20 studies.

RESULTS

Eighteen case reports (8 with SP) showed bullae in the upper lobes in combined cannabis and tobacco smokers (CS) and in the 2 cannabis only smokers (COS). The risk of SP was increased in CS, but not in COS. In patients less than 35-years old presenting with SP, the incidence of bullae on thoracic computed tomography (CT) was higher in CS than in tobacco only smokers (TOS). CT in patients with SP showed no significant difference as regards of the prevalence, location and type of emphysema between CS and TOS. Proportion of low lung density areas was higher in CS than in non-smokers (NS), but was similar in TOS and NS.

CONCLUSION

These results suggest a cumulative toxic effect of tobacco and cannabis on the risk of SP and lung emphysema.

[Helping smoking cessation in COPD, asthma, lung cancer, operated smokers]

Smoking is the cause of addictive behavior. Tobacco addiction is a chronic disease that makes difficult to stop smoking and leads to further use. Smoking is a risk factor for COPD, asthma and lung cancer; it may be the cause of severe perioperative complications. This finding justifies that smokers benefit from advice of stopping smoking and smoking cessation assistance. Helping patients to stop smoking increases the chances of quitting, improves the prognosis of tobacco-related diseases, the effectiveness of their treatments and the quality of life of the patients. This article updates the modalities of smoking cessation assistance in smokers with COPD, asthma and lung cancer in operated patients. The goal of the management must be the complete cessation of tobacco smoke intoxication, which alone reduces tobacco mortality.