Bimoclomol ameliorates mercuric chloride nephrotoxicity through recruitment of stress proteins

Trimetazidine Protects from Mercury-Induced Kidney Injury

INTRODUCTION

The presence of mercury in the environment is a worldwide concern. Inorganic mercury is present in industrial materials, is employed in medical devices, is widely used in batteries, is a component of fluorescent light bulbs, and it has been associated with human poisoning in gold mining areas. The nephrotoxicity induced by inorganic mercury is a relevant health problem mainly in developing countries. The primary mechanism of mercury toxicity is oxidative stress. Trimetazidine (TMZ) is an anti-ischemic drug, which inhibits cellular oxidative stress, eliminates oxygen-free radicals, and improves lipid metabolism. The aim of this study was to evaluate whether the administration of TMZ protects against mercuric chloride (HgCl2) kidney damage.

METHODS

Adult male Wistar rats received only HgCl2 (4 mg/kg bw, sc) (Hg group, n = 5) or TMZ (3 mg/kg bw, ip) 30 min before HgCl2 administration (4 mg/kg bw, sc) (TMZHg group, n = 7). Simultaneously, a control group of rats (n = 4) was studied. After 4 days of HgCl2 injection, urinary flow, urea and creatinine (Cr) plasma levels, Cr clearance, urinary glucose, and sodium-dicarboxylate cotransporter 1 (NaDC1) in urine were determined. Lipid peroxidation (MDA) and glutathione (GSH) levels were measured in kidney homogenates.

RESULTS

Rats only treated with HgCl2 showed an increase in urea and Cr plasma levels, urinary flow, fractional excretion of water, glucosuria, and NaDC1 urinary excretion as compared with the control group and a decrease in Cr clearance. TMZHg group showed a decrease in urea and Cr plasma levels, urinary flow, fractional excretion of water, glucosuria, NaDC1 urinary excretion, and an increase in Cr clearance when compared to the Hg group. Moreover, MDA and GSH levels observed in Hg groups were decreased and increased, respectively, by TMZ pretreatment.

CONCLUSION

TMZ exerted a renoprotective action against HgCl2-induced renal injury, which might be mediated by the reduction of oxidative stress. Considering the absence of toxicity of TMZ, its clinical application against oxidative damage due to HgCl2-induced renal injury should be considered. The fact that TMZ is commercially available should simplify and accelerate the translation of the present data "from bench to bedside." In this context, TMZ become an interesting new example of drug repurposing.

Protective effect of resveratrol against aluminum chloride induced nephrotoxicity in rats

OBJECTIVES

To investigate the potential protective effect of resveratrol (RES) on aluminum chloride (AlCl3)-induced nephrotoxicity in rats.

METHODS

This experimental study was conducted from April to June 2015 at the Medical College of King Khalid University, Abha, Kingdom of Saudi Arabia. The experiments were performed on 24 male Wistar rats. The rats were randomly allocated into 4 groups; 1) group A: control rats received only normal saline, 2) group B: received RES dissolved in normal saline, 3) group C: model group and received AlCl3 dissolved in normal saline and 4) group D: RES treated group and received concomitant doses of RES+AlCl3. All treatments were administered for consecutive 40 days. After 40 days of treatments, kidney function tests, oxidative stress parameters and histopathological assay were evaluated.

RESULTS

all findings clearly showed significant deteriorations in kidney function and architectures after AlCl3 exposure. This was accompanied by increased renal oxidative stress and inflammation suggesting strong pro-oxidant activity of AlCl3 in spite of its non-redox status. Resveratrol co-treatment with AlCl3 to the rats showed significant improvement in all biochemical and histological parameters related to kidney function and structure.

CONCLUSION

The findings of the current study showed that RES pre-administration to rats ameliorates renal damage and improves renal function in AlCl3 intoxicated rats in a mechanism related to its antioxidant potential.

Membrane lipid therapy: Modulation of the cell membrane composition and structure as a molecular base for drug discovery and new disease treatment

Nowadays we understand cell membranes not as a simple double lipid layer but as a collection of complex and dynamic protein-lipid structures and microdomains that serve as functional platforms for interacting signaling lipids and proteins. Membrane lipids and lipid structures participate directly as messengers or regulators of signal transduction. In addition, protein-lipid interactions participate in the localization of signaling protein partners to specific membrane microdomains. Thus, lipid alterations change cell signaling that are associated with a variety of diseases including cancer, obesity, neurodegenerative disorders, cardiovascular pathologies, etc. This article reviews the newly emerging field of membrane lipid therapy which involves the pharmacological regulation of membrane lipid composition and structure for the treatment of diseases. Membrane lipid therapy proposes the use of new molecules specifically designed to modify membrane lipid structures and microdomains as pharmaceutical disease-modifying agents by reversing the malfunction or altering the expression of disease-specific protein or lipid signal cascades. Here, we provide an in-depth analysis of this emerging field, especially its molecular bases and its relevance to the development of innovative therapeutic approaches.

Deletion of multispecific organic anion transporter Oat1/Slc22a6 protects against mercury-induced kidney injury

The primary site of mercury-induced injury is the kidney due to uptake of the reactive Hg(2+)-conjugated organic anions in the proximal tubule. Here, we investigated the in vivo role of Oat1 (organic anion transporter 1; originally NKT (Lopez-Nieto, C. E., You, G., Bush, K. T., Barros, E. J., Beier, D. R., and Nigam, S. K. (1997) J. Biol. Chem. 272, 6471-6478)) in handling of known nephrotoxic doses of HgCl(2). Oat1 (Slc22a6) is a multispecific organic anion drug transporter that is expressed on the basolateral aspects of renal proximal tubule cells and that mediates the initial steps of elimination of a broad range of endogenous metabolites and commonly prescribed pharmaceuticals. Mercury-induced nephrotoxicity was observed in a wild-type model. We then used the Oat1 knock-out to determine in vivo whether the renal injury effects of mercury are mediated by Oat1. Most of the renal injury (both histologically and biochemically as measured by blood urea nitrogen and creatinine) was abolished following HgCl(2) treatment of Oat1 knock-outs. Thus, acute kidney injury by HgCl(2) was found to be mediated mainly by Oat1. Our findings raise the possibility that pharmacological modulation of the expression and/or function of Oat1 might be an effective therapeutic strategy for reducing renal injury by mercury. This is one of the most striking phenotypes so far identified in the Oat1 knock-out. (Eraly, S. A., Vallon, V., Vaughn, D. A., Gangoiti, J. A., Richter, K., Nagle, M., Monte, J. C., Rieg, T., Truong, D. M., Long, J. M., Barshop, B. A., Kaler, G., and Nigam, S. K. (2006) J. Biol. Chem. 281, 5072-5083).

Increased urinary excretion of carnitine and acylcarnitine by mercuric chloride is reversed by 2,3-dimercapto-1-propanesulfonic acid in rats

This investigation was aimed to study the effect of 2,3-dimercapto-1-propanesulfonic acid (DMPS) on mercuric chloride (HgCl(2))-induced alterations in urinary excretion of various carnitine fractions including free carnitine (FC), acylcarnitine (AC), and total carnitine (TC). Different groups of Wistar male rats were treated with HgCl(2) at the doses of 0.1, 0.5, 1.0, 2.0, and 3.0 mg/kg body weight, and the animals were sacrificed at 24 hours following HgCl(2) injection. A separate batch of animals received HgCl(2) (2 mg/kg) with or without DMPS (100 mg/kg) and sacrificed at 24 or 48 hours after dosing. Administration of HgCl(2) resulted in statistically significant and dose-dependent increase in the urinary excretion of FC, AC, and TC in rats. However, the ratio of urinary AC:FC was significantly decreased by HgCl(2). Pretreatment with DMPS offered statistically significant protection against HgCl(2)-induced alterations in various urinary carnitine fractions in rats.