Walker Ulrich A, Venhoff Nils, Koch Eva C, Olschewski Manfred, Schneider Josef, Setzer Bernhard
Department of Rheumatology and Clinical Immunology, Medizinische Universitätsklinik, Freiburg, Germany.
Antivir Ther. 2003 Oct;8(5):463-70.
To assess in vitro if uridine may be suitable to prevent or treat mitochondrial toxicity related to nucleoside analogue reverse transcriptase inhibitors (NRTIs).
Human HepG2-hepatocytes were exposed to NRTIs with or without uridine for 25 days. Cell growth, lactate production, intracellular lipids, mitochondrial DNA (mtDNA) and the ratio between the respiratory chain components COX II (mtDNA-encoded) and COX IV (nuclear-encoded) were measured.
HepG2 cells exposed to zalcitabine (177 nM) without uridine developed a severe depletion of mtDNA (to 8% of wild-type mtDNA levels), resulting in a decline of cell proliferation and COX II levels, with increased lactate and lipid accumulation. Uridine fully abrogated the adverse effects of zalcitabine on hepatocyte proliferation and normalized lactate synthesis, intracellular lipids and COX II levels by adjusting mtDNA levels to about 65% of NRTI-unexposed control cells. This effect was dose-dependent, with a maximum at 200 microM of uridine. Uridine also rapidly and fully restored cell function when added to cells with established mitochondrial dysfunction (zalcitabine for 15 days) despite continued zalcitabine exposure. Uridine also normalized cell proliferation in HepG2 cells exposed to 36 microM of stavudine and protected HepG2-cells exposed to 7 microM of zidovudine + 8 microM of lamivudine (pyrimidine analogues), but failed to improve cell function or mtDNA in cells exposed to 11.8 or 118 microM of didanosine (a purine analogue).
The pyrimidine precursor uridine may attenuate the mitochondrial toxicity of antiretroviral pyrimidine NRTIs in vitro, and its supplementation may represent a promising strategy in the prevention or treatment of mitochondrial toxicities in HIV-infected patients.
在体外评估尿苷是否适合预防或治疗与核苷类似物逆转录酶抑制剂（NRTIs）相关的线粒体毒性。
将人HepG2肝细胞暴露于有或无尿苷的NRTIs中25天。测量细胞生长、乳酸生成、细胞内脂质、线粒体DNA（mtDNA）以及呼吸链成分COX II（mtDNA编码）和COX IV（核编码）之间的比例。
未添加尿苷而暴露于扎西他滨（177 nM）的HepG2细胞出现mtDNA严重耗竭（降至野生型mtDNA水平的8%），导致细胞增殖和COX II水平下降，同时乳酸和脂质积累增加。尿苷完全消除了扎西他滨对肝细胞增殖的不利影响，并通过将mtDNA水平调整至未暴露于NRTIs的对照细胞的约65%，使乳酸合成、细胞内脂质和COX II水平恢复正常。这种作用呈剂量依赖性，在尿苷浓度为200 microM时达到最大值。当添加到已建立线粒体功能障碍（暴露于扎西他滨15天）的细胞中时，尽管持续暴露于扎西他滨，尿苷仍能迅速且完全恢复细胞功能。尿苷还使暴露于36 microM司他夫定的HepG2细胞的细胞增殖恢复正常，并保护暴露于7 microM齐多夫定 + 8 microM拉米夫定（嘧啶类似物）的HepG2细胞，但未能改善暴露于11.8或118 microM去羟肌苷（嘌呤类似物）的细胞的功能或mtDNA。
嘧啶前体尿苷可能在体外减轻抗逆转录病毒嘧啶NRTIs的线粒体毒性，补充尿苷可能是预防或治疗HIV感染患者线粒体毒性的一种有前景的策略。
