Research Recommendations for Selected IARC-Classified Agents: Impact and Lessons Learned

Advanced Liver-on-a-Chip Model for Evaluating Drug Metabolism and Hepatotoxicity

The liver has many important functions, including the biotransformation of drugs and detoxification of the human organism. As such, it is also exposed to many harmful substances, which leads to disorders and diseases such as cirrhosis. For these reasons, it seems important to consider liver metabolism and the direct effects on the liver when evaluating the efficacy of new drugs. Accordingly, we have developed an advanced in vitro liver model using an organ-on-a-chip approach that replicates many of the morphological and functional features of the liver in vivo. The model we created can metabolize drugs, which we demonstrated using two widely used anticancer drugs, 5-fluorouracil (5FU) and capecitabine (CAP). In addition, to the best of our knowledge, we are the first who evaluate the direct effects of these drugs not only on the viability of liver model-building cells but on their functions, such as cytochrome P450 activity and albumin production. Our study brings new hope to properly evaluating drug efficacy at the in vitro level.

Exposures and Bladder Cancer Risk Among Military Veterans: A Systematic Review and Meta-analysis

OBJECTIVE

To investigate potential carcinogenic exposures in military personnel that are implicated in the development of bladder cancer.

METHODS

This systematic review aimed to evaluate the association between specific military exposures and bladder cancer risk among veterans. PubMed, Scopus, and Ovid MEDLINE databases were searched in December 2023 for relevant articles. Inclusion criteria comprised retrospective cohort studies, reviews, and observational studies documenting bladder cancer incidence among military populations exposed to specific agents. A total of 25 studies, involving 4,320,262 patients, met the inclusion criteria. Data extraction followed PRISMA guidelines, and a random-effects model was used for data synthesis.

RESULTS

The meta-analysis revealed significant associations between exposure to Agent Orange (HR 1.17 [95% CI: 1.01-1.36], P < .00001) and depleted uranium (HR 2.13 [95% CI: 1.31-3.48], P = .002) with increased bladder cancer risk among veterans. Contaminated drinking water showed a trend towards increased risk (HR 1.25 [95% CI: 0.97-1.61], P = .08).

CONCLUSION

The findings suggest a possible association between specific military exposures and heightened bladder cancer risk among veterans, emphasizing the necessity for targeted screening protocols and preventive measures. Further research is essential to identify specific carcinogenic agents and prevalence of exposures among veterans, enabling more effective prevention and management strategies.

Circadian epidemiology: Structuring circadian causes of disease and practical implications

That disruptions of the body's internal clockwork can lead to negative health consequences, including cancer, is a plausible hypothesis. Yet, despite strong mechanistic and animal support, the International Agency for Research on Cancer (IARC) experts considered epidemiological evidence as limited regarding the carcinogenicity of "shift-work involving circadian disruption" (2007) and "night shift work" (2019). We use directed acyclic graphs (DAGs) to outline a concept of circadian causes that discloses challenges when choosing appropriate exposure variables. On this basis, we propose to move beyond shift-work alone as a direct cause of disease. Instead, quantifying chronodisruption as individual doses can lead to interpretable circadian epidemiology. The hypothesis is that doses of chronodisruption cause disrupted circadian organisation by leading to desynchronization of circadian rhythms. Chronodisruption can be conceptualized as the split physiological nexus of internal and external times. Biological (or internal) night - an individual's intrinsically favoured sleep time window - could be the backbone of circadian epidemiology. In practice, individual doses that cause disrupted circadian organisation are derived from the intersection of time intervals of being awake and an individual's biological night. After numerous studies counted work shifts, chronobiology may now advance circadian epidemiology with more specific dose estimation - albeit with greater challenges in measurement (time-dependent individual data) and analysis (time-dependent confounding).