Liver transcriptomic changes associated with ritonavir-induced hyperlipidemia in sensitive and resistant strains of rats

Meta-analysis of the global prevalence of Enterococcus spp. in foods: Antibiotic resistance profile of Enterococcus faecalis and Enterococcus faecium

Aim: The objective of this study was to evaluate the prevalence and diversity of Enterococcus spp. and antibiotic-resistant Enterococcus faecalis and Enterococcus faecium isolates in different foods worldwide.

Method and Result: This study used meta-analytical methods. Besides, Web of Science (n= 705), Medline (n= 6), and Scopus (n= 1.338) were searched for studies in the years 1995-2021 using related keywords. Results showed that the pooled prevalence for Enterococcus spp. and antibiotic-resistant of E. faecalis and E. faecium isolates were found 0.41 (95% C.I. 0.34-0.47), 0.25 (95% C.I. 0.13-0.38), respectively. According to the results of the subgroup analysis, the lowest and highest prevalence of Enterococcus spp. in food types were calculated for red meat (0.56), and fermented foods (0.29). Also, as a result of subgroup analyses by country the highest prevalence of Enterococcus spp. was calculated in studies conducted in Slovakia (0.74). In contrast, the lowest prevalence was calculated in studies conducted in Georgia (0.07).

Conclusion: The meta-analyses improved our understanding of the prevalence of Enterococcus spp. and the antibiotic resistance of E. faecalis and E. faecium isolates in different foods and provided results that can be useful as input for quantitative microbiological risk evaluation modeling.

Significance and Impact of Study: We demonstrated the antibiotic resistance of E. faecalis and E. faecium in foods and gaps that could be addressed in the future. Therefore, it is believed that the results compiled herein will contribute to the epidemiological surveillance of the presence and antibiotic resistance of E. faecalis and E. faecium in foods.

Toxicology Strategies for Drug Discovery: Present and Future

Attrition due to nonclinical safety represents a major issue for the productivity of pharmaceutical research and development (R&D) organizations, especially during the compound optimization stages of drug discovery and the early stages of clinical development. Focusing on decreasing nonclinical safety-related attrition is not a new concept, and various approaches have been experimented with over the last two decades. Front-loading testing funnels in Discovery with in vitro toxicity assays designed to rapidly identify unfavorable molecules was the approach adopted by most pharmaceutical R&D organizations a few years ago. However, this approach has also a non-negligible opportunity cost. Hence, significant refinements to the "fail early, fail often" paradigm have been proposed recently to reflect the complexity of accurately categorizing compounds with early data points without taking into account other important contextual aspects, in particular efficacious systemic and tissue exposures. This review provides an overview of toxicology approaches and models that can be used in pharmaceutical Discovery at the series/lead identification and lead optimization stages to guide and inform chemistry efforts, as well as a personal view on how to best use them to meet nonclinical safety-related attrition objectives consistent with a sustainable pharmaceutical R&D model. The scope of this review is limited to small molecules, as large molecules are associated with challenges that are quite different. Finally, a perspective on how several emerging technologies may impact toxicity evaluation is also provided.

Mg supplementation protects against ritonavir-mediated endothelial oxidative stress and hepatic eNOS downregulation

Ritonavir (RTV), a prototypical protease inhibitor currently used as a key component of anti-HIV therapy, is known for its endothelial and hepatic toxicity. The effects of RTV and magnesium supplementation on cultured bovine endothelial cell (EC) and rat hepatic endothelial nitric oxide synthase (eNOS) status were investigated. RTV dose-dependently (5-30 µM) decreased EC viability after 48 h; high Mg (2mM) significantly attenuated the lost viability. ECs incubated with 15 µM RTV for 6 to 24h resulted in two- to fourfold elevation of oxidized glutathione and a 25% loss of total glutathione. At 24h, EC superoxide production due to RTV was detected by dihydroethidium staining and increased 41% when quantified by flow cytometry; altered glutathione status and superoxide levels were both substantially reversed by 2mM Mg. RTV reduced eNOS mRNA (-25% at 24 h) and led to decreased eNOS dimer/monomer ratios; nitric oxide-derived products decreased 40%; both changes were attenuated by Mg supplementation. In male Lewis-Brown Norway rats, RTV administration (75 mg/kg/day, 5 weeks) resulted in an 85% increase in plasma 8-isoprostane and a 23% decrease in hepatic eNOS mRNA; concomitantly, eNOS protein decreased 75%, whereas plasma nitrite level was reduced 48%. Dietary Mg supplementation (sixfold higher than control) prevented the eNOS mRNA decrease along with lowering 8-isoprostane and restored the eNOS protein and plasma nitrite levels comparable to controls. In conclusion, Mg attenuates RTV-mediated EC oxidative eNOS dysfunction and downregulation of hepatic eNOS expression; we suggest that Mg can serve as a beneficial adjunct therapeutic against RTV-mediated eNOS toxicity.

Antiretroviral drugs induce oxidative stress and neuronal damage in the central nervous system

HIV-associated neurocognitive disorder (HAND), characterized by a wide spectrum of behavioral, cognitive, and motor dysfunctions, continues to affect approximately 50 % of HIV(+) patients despite the success of combination antiretroviral drug therapy (cART) in the periphery. Of note, potential toxicity of antiretroviral drugs in the central nervous system (CNS) remains remarkably underexplored and may contribute to the persistence of HAND in the cART era. Previous studies have shown antiretrovirals (ARVs) to be neurotoxic in the peripheral nervous system in vivo and in peripheral neurons in vitro. Alterations in lipid and protein metabolism, mitochondrial damage, and oxidative stress all play a role in peripheral ARV neurotoxicity. We hypothesized that ARVs also induce cellular stresses in the CNS, ultimately leading to neuronal damage and contributing to the changing clinical and pathological picture seen in HIV-positive patients in the cART era. In this report, we show that ARVs are neurotoxic in the CNS in both pigtail macaques and rats in vivo. Furthermore, in vitro, ARVs lead to accumulation of reactive oxygen species (ROS), and ultimately induction of neuronal damage and death. Whereas ARVs alone caused some activation of the endogenous antioxidant response in vitro, augmentation of this response by a fumaric acid ester, monomethyl fumarate (MMF), blocked ARV-induced ROS generation, and neuronal damage/death. These findings implicate oxidative stress as a contributor to the underlying mechanisms of ARV-induced neurotoxicity and will provide an access point for adjunctive therapies to complement ARV therapy and reduce neurotoxicity in this patient population.

Mg supplementation attenuates ritonavir-induced hyperlipidemia, oxidative stress, and cardiac dysfunction in rats

Use of protease inhibitors (PI) in HIV patients is associated with hyperlipidemia and increased risk of coronary heart disease. Chronic systemic and cardiac effects of ritonavir (RTV), a universal PI booster, and Mg supplementation were examined. RTV was administered (75 mg·kg(-1)·day(-1) po) to Lewis × Brown-Norway hybrid (LBNF1) rats for up to 8 wk; significant increases in plasma triglyceride and cholesterol occurred from 8 days to 8 wk. At 5 wk, the expression of selected hepatic genes (CYP7A1, CITED2, G6PC, and ME-1), which are key to lipid catabolism/synthesis, were altered toward lipogenesis. Dietary Mg supplementation (six-fold higher) completely reversed the altered expression of these genes and attenuated both hypertriglyceridemia and hypercholesterolemia. Neutrophils isolated from the RTV-treated rats displayed a three-fold higher basal and a twofold higher stimulated superoxide production; plasma isoprostane and red blood cell (RBC) GSSG levels were elevated two- to three-fold. All oxidative indices were normalized by Mg supplementation. After 5 wk, RTV caused significant decreases in cardiac left ventricular (LV) shortening fraction and LV ejection fraction; mitral valve early/late atrial ventricular filling (E/A) ratio was reduced accompanied by LV posterior wall thinning. Immunohistochemical staining revealed significant white blood cell (WBC) infiltration (5 wk) and prominent fibrosis (8 wk) in the RTV hearts. Mg supplementation attenuated RTV-induced declines in systolic and diastolic (improved mitral valve E/A ratio) function (>70%), lessened LV posterior wall thinning (by 75%), and substantially decreased the pathological markers. The known clinical hyperlipidemia effects of RTV can be mimicked in the LBNF1 rats; in association, systemic oxidative stress and progressive cardiac dysfunction occurred. Remarkably, Mg supplementation alone suppressed RTV-mediated hyperlipidemia, oxidative stress, and cardiac dysfunction.