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Glyphosate, an herbicidal derivative of the amino acid glycine, was introduced to agriculture in the 1970s. Glyphosate targets and blocks a plant metabolic pathway not found in animals, the shikimate pathway, required for the synthesis of aromatic amino acids in plants. After almost forty years of commercial use, and multiple regulatory approvals including toxicology evaluations, literature reviews, and numerous human health risk assessments, the clear and consistent conclusions are that glyphosate is of low toxicological concern, and no concerns exist with respect to glyphosate use and cancer in humans. This manuscript discusses the basis for these conclusions. Most toxicological studies informing regulatory evaluations are of commercial interest and are proprietary in nature. Given the widespread attention to this molecule, the authors gained access to carcinogenicity data submitted to regulatory agencies and present overviews of each study, followed by a weight of evidence evaluation of tumor incidence data. Fourteen carcinogenicity studies (nine rat and five mouse) are evaluated for their individual reliability, and select neoplasms are identified for further evaluation across the data base. The original tumor incidence data from study reports are presented in the online data supplement. There was no evidence of a carcinogenic effect related to glyphosate treatment. The lack of a plausible mechanism, along with published epidemiology studies, which fail to demonstrate clear, statistically significant, unbiased and non-confounded associations between glyphosate and cancer of any single etiology, and a compelling weight of evidence, support the conclusion that glyphosate does not present concern with respect to carcinogenic potential in humans.

Background/Aims: Oxidative stress is involved in sepsis-related endothelium dysfunction. Selenoprotein-P (Sel-P), the main plasma selenoprotein, may have high antioxidant potential, and binds to endothelium. We hypothesize that, in septic shock, and similar syndromes such as systemic inflammatory response syndrome (SIRS), Sel-P binds massively to endothelium, causing a drop in Sel-P plasma concentration. Methods: Plasma Se, Sel-P and albumin concentrations, and glutathione peroxidase (GPx) activity were measured in patients with septic shock and SIRS with organ failure (S group, n = 7 and n = 3, respectively) admitted to the intensive care unit (ICU) and compared to non-SIRS patients (NS group, n = 11) and healthy volunteers (HV group, n = 7). Results: On ICU admission, plasma Sel-P concentrations were 70% lower in the S group than in the other groups [15 (10–26) vs. 44 (29–71) and 50 (45–53) nmol/l] and were lower in nonsurviving septic-shock patients. GPx activity did not differ between groups. Sel-P was significantly lower before ICU death in the 3 deceased patients of the S group (septic shock) than in the 3 patients of the non-SIRS group. Conclusions: Early decrease in Sel-P plasma concentrations was specifically observed in septic shock and was similar in SIRS patients whereas GPx activity remained unchanged. Further studies are needed to determine whether Sel-P can be an early marker of septic shock linked to microvascular injury.

Selenium (Se) and vitamin E are antioxidant micronutrients. Se functions through selenoproteins and vitamin E reacts with oxidizing molecules in membranes. The relationship of these micronutrients with the Nrf2-antioxidant response element (ARE) pathway was investigated using ARE-reporter mice and Nrf2-/- mice. Weanling males were fed Se-deficient (0 Se), vitamin E-deficient (0 E), or control diet for 16 or 22 weeks. The ARE reporter was elevated 450-fold in 0 Se liver but was not elevated in 0 E liver. Antioxidant enzymes induced by Nrf2-ARE (glutathione S-transferase (GST), NAD(P)H quinone oxidoreductase (NQOR), and heme oxygenase-1 (HO-1)) were elevated in 0 Se livers but not in 0 E livers. Deletion of Nrf2 had varying effects on the inductions, with GST induction being abolished by it but induction of NQOR and HO-1 still occurring. Thus, Se deficiency, but not vitamin E deficiency, induces a number of enzymes that protect against oxidative stress and modify xenobiotic metabolism through Nrf2-ARE and other stress-response pathways. We conclude that Se deficiency causes cytosolic oxidative stress but that vitamin E deficiency does not. This suggests that the oxidant defense mechanisms in which these antioxidant nutrients function are independent of one another.

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