Toxicologie environnementale et analytique

Is Glyphosate a Key Factor in Mesoamerican Nephropathy?

Abstract

Stephanie Seneff and Laura F Orlando

Mesoamerican nephropathy (MeN), also known as chronic kidney disease of unknown etiology (CKDu), is an unusual form of kidney disease not associated with diabetes, hypertension, or glomerular nephritis. It has a number of known risk factors, none of which adequately explain the skyrocketing prevalence of the disease among sugarcane workers in El Salvador and Nicaragua. In this paper, we narrow the research focus from agricultural chemicals, in general, to glyphosate, in particular, an herbicide routinely used on sugarcane. We explain how glyphosate compellingly contributes to CKDu, by reviewing the evidence for glyphosate’s direct toxicity to kidneys and showing how the herbicide amplifies the damage to kidneys from other known risk factors. Using standard web search on index words and phrases, we gathered and perused a large collection of papers describing the pathology of MeN and associated metrics, on the one hand, and the mechanisms of toxicity of glyphosate in humans, animals and in in vitro studies, on the other hand. We show that glyphosate is used on sugarcane in three distinct ways, with exposure greatest when the herbicide is used as a ripener near harvest time. We identify several pathologies associated with MeN that have been found to be implicated in papers on glyphosate exposure, such as enhancing the growth of Clostridia species and fungus, promoting arsenic toxicity, suppressing the synthesis of adrenocorticotropic hormone (ACTH), disrupting fructose metabolism, and promoting dehydration and high serum urate. A companion paper explains how glyphosate’s substitution for glycine could cause additional renal damage. Together, these two papers strongly suggest that glyphosate is a causative agent in CKDu. Overall, the research literature provides compelling evidence that glyphosate exposure is a significant factor in MeN. Glyphosate usage on crops should be curtailed in order to protect the agricultural worker population from this devastating and life-threatening disease.