Breaking the ritual metabolic cycle in order to save acetyl CoA: A potential role for mitochondrial humanin in T2 bladder cancer aggressiveness.

INTRODUCTION: Cancer cells may exhibit outsourcing of their high energy need in order to avoid the intrinsic mitochondrial apoptosis. Reduced mitochondrial respiration and accumulation of mitochondrial genome mutations are among metabolic transformations in this regard. Mitochondrial humanin (MT-RNR2) is a small peptide with anti-apoptotic activities attributed to binding some pro-apoptotic proteins. AIM OF THE WORK: The current study aims at investigating the expression of mitochondrial humanin in bladder tumor cells and the possible casting of humanin anti-apoptotic action through orchestrating some of the mitochondrial metabolic enzymes. MATERIAL AND METHODS: Here messenger RNA of humanin, succinate dehydrogenase, glutaminase, isocitrate dehydrogenase were compared in tissues from patients with T2 bladder carcinoma in comparison to tumor associated normal tissues from the same patients. Levels of lactate and mitochondrial pyruvate carrier (MPC1) mRNA were determined to scrutinize the prevalence of aerobic glycolysis. RESULTS: The present study found that tumor cells had suppressed aerobic glycolysis, augmented mitochondrial respiration and interrupted tricarboxylic acid cycle, all of which were suggested to serve tumor aggressiveness. MT-RNR2 was found closely related to the alterations in mitochondrial activity. CONCLUSION: MT-RNR2 plays its anti-apoptotic role partly by avoiding deploying energy from complete oxidation of organic compounds to inorganic wastes. Thus MT-RNR2 can potentially serve as a new biomarker in the diagnosis of bladder carcinoma especially that it is present in blood circulation.

Safety of Intracameral Injection of Minimal Bactericidal Concentration of Povidone Iodine on the Corneal Endothelium in a Rabbit Model.

PURPOSE: To investigate the safety of intracameral injection of minimum bactericidal concentration (MBC) of povidone iodine (PI) on the corneal endothelium in a rabbit model as a proposed method of prophylaxis against postoperative endophthalmitis. METHODS: We included 32 New Zealand white rabbits in the study. Twenty-four rabbits received intracameral injections of 0.1 mL of 0.25% PI, and they were sequentially killed at intervals; first, seventh, and 14th day. The control group included 4 rabbits that received intracameral injections of 0.1 mL normal saline, and 4 rabbits that underwent the same intraocular procedure without injections (sham operated). Slit-lamp examination and ultrasonic corneal pachymetry were performed before and after injections for both eyes. The corneas were histopathologically examined by light and electron microscopy. RESULTS: MBC of PI (0.25%) was toxic to rabbits' corneal endothelium as evident by histopathological changes, corneal edema, and increased corneal thickness on day 1. Signs of healing were obvious on day 7 and were almost complete on day 14, as detected by histopathology, subsidence of corneal edema, and normalization of corneal thickness. CONCLUSIONS: MBC (0.25%) of PI was found toxic to the rabbits' corneal endothelium, with progressive regeneration and complete healing within 2 weeks. To our knowledge, we are the first to use MBC of PI in intracameral injection trials. Further studies on primates, which have more comparable regenerative capacity to humans' corneal endothelium, are encouraged to evaluate their endothelial healing response.

Ameliorative effect of acetyl-L-carnitine and/or nifedipine against selenite-induced cataractogenesis in young albino rats.

Free radical toxicity and calcium ion overload have been identified as the major two players in the causation of cataract. The current study was carried out to investigate the anti-cataractogenic effect of single and combined treatment with acetyl-l-carnitine and nifedipine in sodium selenite-induced cataract. Rat pups were divided into 5 groups; 1st group received intraperitoneal injection (i.p.) of saline and served as normal control, 2nd group received single subcutaneous injection of sodium selenite 30nmol/g body weight on p10 (postpartum day 10), 3rd and 4th groups received either acetyl-l-carnitine (200mg/kg, i.p.) or nifedipine (0.1mg/kg, i.p.) on p9, respectively, before the administration of sodium selenite, and the treatment continued till p14. Last group received the combined treatments of acetyl-l-carnitine and nifedipine in the same regimen. All animals were examined using a slit lamp and retroillumination then sacrificed on p30. Lenses were removed and processed for biochemical analyses, histopathological and electron microscopic examination. Selenite-treated groups showed significantly (P≤0.05) lower values of redox system components (glutathione and glutathione reductase activity) and anti-oxidant enzymes׳ activities (superoxide dismutase and catalase) along with increased lipid peroxidation that was accompanied by 100% opacified crystalline lenses (mature cataract) with abnormal structure as detected by electron microscopy. It is concluded that acetyl-l-carnitine or nifedipine was able to partially protect against selenite-induced abnormalities. While, combined treatment with acetyl-l-carnitine and nifedipine was superior to individual treatments in slowing down the development of cataract by restoring the anti-oxidant defense and mitigating lipid peroxidation in the lens and hence represents an attractive anti-cataractogenic remedy.