Therapy for CKD-associated muscle dysfunction

Background Chronic kidney disease (CKD) patients experience skeletal muscle wasting and decreased exercise endurance. Our previous study demonstrated that indoxyl sulfate (IS), a uremic toxin, accelerates skeletal muscle atrophy. The purpose of this study was to examine the issue of whether IS causes mitochondria dysfunction and IS-targeted intervention using AST-120, which inhibits IS accumulation, or mitochondria-targeted intervention using L-carnitine or teneligliptin, a dipeptidyl peptidase-4 inhibitor which retains mitochondria function and alleviates skeletal muscle atrophy and muscle endurance in chronic kidney disease mice. Methods The in vitro effect of IS on mitochondrial status was evaluated using mouse myofibroblast cells (C2C12 cell). The mice were divided into sham or 5/6-nephrectomized (CKD) mice group. Chronic kidney disease mice were also randomly assigned to non-treatment group and AST-120, L-carnitine, or teneligliptin treatment groups. Results In C2C12 cells, IS induced mitochondrial dysfunction by decreasing the expression of PGC-1α and inducing autophagy in addition to decreasing mitochondrial membrane potential. Co-incubation with an anti-oxidant, ascorbic acid, L-carnitine, or teneligliptine restored the values to their original state. In CKD mice, the body and skeletal muscle weights were decreased compared with sham mice. Compared with sham mice, the expression of interleukin-6 and atrophy-related factors such as myostatin and atrogin-1 was increased in the skeletal muscle of CKD mice, whereas muscular Akt phosphorylation was decreased. In addition, a reduced exercise capacity was observed for the CKD mice, which was accompanied by a decreased expression of muscular PCG-1α and increased muscular autophagy, as reflected by decreased mitochondria-rich type I fibres. An AST-120 treatment significantly restored these changes including skeletal muscle weight observed in CKD mice to the sham levels accompanied by a reduction in IS levels. An L-carnitine or teneligliptin treatment also restored them to the sham levels without changing IS level. Conclusions Our results indicate that IS induces mitochondrial dysfunction in skeletal muscle cells and provides a potential therapeutic strategy such as IS-targeted and mitochondria-targeted interventions for treating CKD-induced muscle atrophy and decreased exercise endurance

Biology and genome of a newly discovered sibling species of Caenorhabditis elegans

A ‘sibling’ species of the model organism Caenorhabditis elegans has long been sought for use in comparative analyses that would enable deep evolutionary interpretations of biological phenomena. Here, we describe the first sibling species of C. elegans, C. inopinata n. sp., isolated from fig syconia in Okinawa, Japan. We investigate the morphology, developmental processes and behaviour of C. inopinata, which differ significantly from those of C. elegans. The 123-Mb C. inopinata genome was sequenced and assembled into six nuclear chromosomes, allowing delineation of Caenorhabditis genome evolution and revealing unique characteristics, such as highly expanded transposable elements that might have contributed to the genome evolution of C. inopinata. In addition, C. inopinata exhibits massive gene losses in chemoreceptor gene families, which could be correlated with its limited habitat area. We have developed genetic and molecular techniques for C. inopinata; thus C. inopinata provides an exciting new platform for comparative evolutionary studies

Hepatic Arterial Infusion Therapy with Cisplatin using Protein Binding Inhibition : Pharmacokinetics and Antineoplastic Effects of Cisplatin Combined with L-Cysteine in Rats

Cisplatin の蛋白結合には共有結合が関与しており、L-cysteine はcisplatin の共有結合を低下させる。そこで、この蛋白結合阻害を利用してcisplatin の肝動注療法の応用性について検討を行った。実験では、Donryu系雄性ラットにおけるL-cysteine 併用時におけるcisplatin の体内動態と抗腫瘍効果の影響について検討した。その結果、L-cysteine 併用においてcisplatin のtotal とfree 濃度に有意な差はみられなかった。また肝癌ラットを使用したin vivo 実験系において、L-cysteine を併用したcisplatin の肝動注はcisplatin のみの投与に比べ、腫瘍増殖率が抑えられる傾向であることを示した。さらに肝組織中における腫瘍部と非腫瘍部におけるcisplatin 濃度において、L-cysteine 併用により腫瘍部と非腫瘍部に有意な差を認めることができた (p<0.01)。以上の結果より、L-cysteine の併用はcisplatin の肝動注療法へ応用できると考えられる。Covalent binding is involved in the protein binding of cisplatin. L-cysteine reduces the covalent binding of cisplatin. We investigated hepatic arterial infusion therapy with cisplatin using protein binding inhibition. In the present experiment, the pharmacokinetics and antineoplastic effects of cisplatin combined with L-cysteine in male Donryu rats were investigated. As a result, no significant difference was noted in the total and free concentrations of cisplatin combined with L-cysteine. In an in vivo experiment using rats with liver cancer, the hepatic arterial infusion of cisplatin combined with L-cysteine showed that it was the tendency that tumor growth rate was inhibited in comparison with administration only for cisplatin. In addition, concentrations of cisplatin increased significantly between tumor and non-tumor regions in liver tissue when combined with L-cysteine (p<0.01). Thus, L-cysteine can be combined with cisplatin for hepatic arterial infusion therapy

ニジ セイ フク コウジョウセン キノウ コウシンショウ ニ オケル ヤクブツ ドウタイ セイギョ キノウ タンパクシツ ノ ハツゲン ヘンドウ ト ソノ ブンシ キコウ オヨビ ビョウタイ セイリ カイセキ

熊本大