Amy Mok

Detrimental effects of prolonged warm renal ischaemia-reperfusion injury are abrogated by supplemental hydrogen sulphide: an analysis using real-time intravital microscopy and polymerase chain reaction.

Whats known on the subject? and What does the study add?

Supplemental hydrogen sulphide protects transplant kidney function and prolongs recipient survival after prolonged cold ischaemia-reperfusion injury by mitigating renal graft apoptosis and inflammation.

Whats known on the subject? and What does the study add?

CDP-diacylglycerol synthesis in rat liver mitochondria

CDP‐diacylglycerol for polyglycerophosphatide biogenesis can be synthesized within rat liver mitochondria. This membrane‐associated enzyme was predominantly located in the inner mitochondrial membrane. GTP had a significant effect in activating the microsomal CDP‐diacylglycerol synthase, especially if the microsomes were preincubated with GTP in the presence of phosphatidic acid. This stimulatory effect of GTP on the microsomal enzyme was not detected in the mitochondrial fractions. The enzymes could be solubilized from the membrane fractions using CHAPS, and the detergent‐soluble activity partially restored by addition of phospholipids. Mitochondrial and microsomal CDP‐diacylglycerol synthase activity could be completely separated by anion‐exchange column chromatography. The mitochondrial and microsomal CDP‐diacylglycerol synthases appear to be two distinct enzymes with different localization and regulatory characteristics.

Examination of the potential role of the glycerophosphorylcholine (GPC) pathway in the biosynthesis of phosphatidylcholine by liver and lung

The potential involvement of the glycerophosphorylcholine (GPC) pathway for the synthesis of phosphatidylcholine (PC) has been examined in rat liver and lung and in a human line, the A549 cell which possesses characteristics representative of mature alveolar type II epithelial cells. Although mitochondrial and microsomal fractions from the above sources readily incorporated radioactive glycerophosphate into lipids, the only incorporation observed with radioactive GPC was a small variable labelling with the mitochondrial and microsomal fractions from rat lung. Even with these fractions, no radioactivity from GPC was incorporated into PC or lysoPC. Attempts to increase the incorporation of GPC into lipids by manipulating the incubation conditions were unsuccessful. It was concluded that the occurrence of the GPC pathway in liver and lung is unlikely.

Hydrogen Sulfide Induced Erythropoietin Synthesis is Regulated by HIF Proteins

PURPOSE Anemia of end stage renal disease affects 90% of patients on hemodialysis and it is a tremendous concern of patients and health care providers. Renal disease creates a state of renal hypoxia, which may contribute to a lack of erythropoietin production from the kidney when low oxygen levels are sensed. This necessitates the use of exogenous erythropoietin preparations. MATERIALS AND METHODS Recent evidence suggests that endogenously derived hydrogen sulfide may mediate oxygen sensing in tissues. Given the known involvement of other small molecules such as nitric oxide in erythropoietin production and the observation of decreased urinary H2S levels in patients with renal failure, we postulated that H2S may be the primary mediator of erythropoietin production during hypoxia. PK1, 786-O and Hep3B cells were incubated in hypoxia (1% O2) for 24 hours. Hypoxic cells were treated with the H2S donor GYY 4137 and the H2S inhibitor hydroxylamine. Following hypoxia erythropoietin, HIF-1α, HIF-2α and CBS expression was measured by quantitative real-time polymerase chain reaction and Western blot. RESULTS Hydroxylamine administration led to a significant decrease in erythropoietin, HIF-1α, HIF-2α and CBS protein levels during hypoxia. This was rescued by administration of GYY 4137 for erythropoietin, CBS and HIF-2α. Additionally, CSE -/- mice placed in hypoxia for 72 hours showed decreased renal erythropoietin production compared to wild-type mice. CONCLUSIONS These data suggest previously undocumented interplay of the production and action of H2S during hypoxia with subsequent erythropoietin production. The use of novel hydrogen sulfide donors could represent an alternative to standard therapies of anemia of renal failure.

MP58-18 EXOGENOUS HYDROGEN SULFIDE TREATMENT REDUCES RENAL FIBROSIS ASSOCIATED WITH CHRONIC URETERAL OBSTRUCTION BY ATTENUATING EPITHELIAL-MESENCHYMAL TRANSITION

FT-IR to determine the biochemical structure and the matrix material content. The matrix material component was calculated as percentage to total biochemical components. The stone microanalysis for heavy metals and trace elements contents (22 elements/stone) was carried out by using ICP-OES. The correlation between matrix material content, biochemical structure and heavy metals was evaluated. RESULTS: FT-IR analyses revealed; 268 (48.6%) Ca oxalate, 166 (30.15) uric acid, 68 (12.3%) mixed and 19 (3.4) Ca phosphate, 13 (2.4%) struvite and 12 (2.2%) cystine stones. ICP-OES showed significant increase in the concentrationof 15 elements (Al, B, Ba,Ca,Cd,Cr, K, Mg, Na, P, Pb, S, Se, Sr and Zn) within the examined urinary stones. Phosphate-based stones (Ca phosphate and Struvite) had the highest concentration of Al, B, Ba, Cr, K, Mg, Na, P, Pb, Sr and Zinc. Calciumbased (Oxalate) stones had high levels of Cd,Fe, Mo and Se. Uric acid stones had high concentration of S. The mean percentage of matrix material was 6.4%. 195 (35.3%) stones had zero matrix content. 190 (34.4%) had matrix material < 6.4%. Zero matrix stones had high concentration of heavymetals (Al, As,Ba,Ca,Cd,Cr, Cu, Fe,Mn,Mo,Naand P). High matrix-containing stones had only higher Se than low matrix. CONCLUSIONS: The human urinary stones contained a significant concentration of heavy and trace elements. Phosphate-based stones had highest concentration of HMTE. Uric acid stones had the least contents of HMTE. Matrix-rich stones had less contents of HMTE. Poor Matrix-containing stones had highest contents of HMTE. These results indicate that matrix material could play an equally important role in stone formation beside other micro-components specially HMTE.