72 Allopurinol has a protective effect in diseases involving oxidative stress in their pathogenesis. Allopurinol treatment

of diabetic mice attenuated hyperuricaemia, albuminuria, and tubulo-interstitial injury.73 Several studies in human CKD patients have shown the benefit of treatment with allopurinol. For example, Kao et al. reported that allopurinol ameliorated endothelial dysfunction and prevented increased left ventricular mass in patients with CKD,74 and Siu et al. reported that allopurinol slowed progression of CKD through its ability to lower serum uric acid levels.75 The kidneys contain the highest endogenous levels of CoQ9 and CoQ10 compared with all other organs.76 This is likely due to the reliance of the kidney on aerobic metabolism and high density of mitochondria. It is learn more imperative that endogenous CoQ10 levels are maintained to ensure mitochondrial health, and this forms the rationale for CoQ10 therapy. CoQ10 has three well-characterized functions: (i) the transfer of electrons from complexes I and II to complex III along the ETC of the inner mitochondrial membrane and subsequent membrane polarization and ATP generation;77 (ii) the pro-oxidant generation PD0325901 solubility dmso of

O2- and H2O2;78 and (iii) the anti-oxidant quenching of free radicals.79 The major direct anti-oxidant role of CoQ10 is prevention of lipid peroxidation, and it also acts indirectly through its interactions with α-tocopherol.80 Although results regarding its benefit are disparate, Ishikawa and colleagues81 demonstrated a decrease in kidney O2- levels and improved renal function in hemi-nephrectomized rats on a CoQ10 supplemented diet. There is a general lack almost of human studies investigating CoQ10 therapy for the treatment and/or prevention of CKD, but CoQ10 levels decrease with age82 and identification of patients with low CoQ10 levels may allow for targeted therapy with beneficial outcome. Mitochondrial-targeted compounds have created much interest for their application in reducing oxidative stress. One of the most tested is the mitochondrial-targeted derivative of endogenous CoQ10, termed MitoQ (mitoquinone

mesylate). This compound and those alike, such as mitochondrial-targeted vitamin E (MitoVitE), are prepared by covalently attaching a lipophilic cation to an alkyltriphenylphosphonium, allowing rapid accumulation into the mitochondria driven by the large negative value of the mitochondrial membrane potential. Administration of MitoQ in a rat model of diabetic nephropathy decreased mesangial expansion and tubulointerstitial fibrosis, thereby improving renal function.83 Human trials have shown that MitoQ can decrease biomarkers of liver inflammation in hepatitis C patients.84 However, a larger scale, double-blinded, placebo-controlled study found that MitoQ did not slow the progression of untreated Parkinson’s disease, a disease associated with mitochondrial oxidative stress.