The microenvironment matters

Mammary microbial dysbiosis leads to the zoonosis of bovine mastitis: a One-Health perspective

Bovine mastitis is a prototypic emerging and reemerging bacterial disease that results in cut-by-cut torture to animals, public health and the global economy. Pathogenic microbes causing mastitis have overcome a series of hierarchical barriers resulting in the zoonotic transmission from bovines to humans either by proximity or remotely through milk and meat. The disease control is challenging and has been attributed to faulty surveillance systems to monitor their emergence at the human-animal interface. The complex interaction between the pathogens, the hidden pathobionts and commensals of the bovine mammary gland that create a menace during mastitis remains unexplored. Here, we review the zoonotic potential of these pathogens with a primary focus on understanding the interplay between the host immunity, mammary ecology and the shift from symbiosis to dysbiosis. We also address the pros and cons of the current management strategies and the extent of the success in implementing the One-Health approach to keep these pathogens at bay.

Filling the gap between risk assessment and molecular determinants of tumor onset

In the past two decades, a ponderous epidemiological literature has causally linked tumor onset to environmental exposure to carcinogens. As consequence, risk assessment studies have been carried out with the aim to identify both predictive models of estimating cancer risks within exposed populations and establishing rules for minimizing hazard when handling carcinogenic compounds. The central assumption of these works is that neoplastic transformation is directly related to the mutational burden of the cell without providing further mechanistic clues to explain increased cancer onset after carcinogen exposure. Nevertheless, in the last few years, a growing number of studies have implemented the traditional models of cancer etiology, proposing that neoplastic transformation is a complex process in which several parameters and crosstalk between tumor and microenvironmental cells must be taken into account and integrated with mutagenesis. In this conceptual framework, the current strategies of risk assessment that are solely based on the 'mutator model' require an urgent update and revision to keep pace with advances in our understanding of cancer biology. We will approach this topic revising the most recent theories on the biological mechanisms involved in tumor formation in order to envision a roadmap leading to a future regulatory framework for a new, protective policy of risk assessment.