Cytotoxicity is predicted by unbound and not total billrubin concentration
Cytotoxicity is predicted by unbound and not total billrubin concentration
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DOI：
10.1203/pdr.0b013e3181568c94
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发表时间：
2007-11-01
影响因子：
3.6
通讯作者：
Tiribelli, Claudio
中科院分区：
文献类型：
--
作者：
Calligaris, Sebastian D.;Bellarosa, Cristina;Tiribelli, Claudio
尽管已有研究表明，游离胆红素水平(B-f)而不是总胆红素水平(B-T)与细胞毒性有关，但支持该结论的直接实验证据有限。此外，以前的研究从未使用更新、更准确的方法直接测量Bf。为了验证“游离胆红素假说”，通过改变B-T/白蛋白比值、使用具有不同结合亲和力的血清白蛋白和/或用磺胺取代白蛋白中的未结合胆红素(UCB)，在体外评估了四种细胞株在不同Bf浓度下的细胞毒性。用改良的最低限度稀释的过氧化物酶方法测定BF。不同细胞系的细胞毒性不同，但总是与B-f有关，而与B-T无关。光暴露降低了毒性，与B-f的降低平行。在没有白蛋白的情况下，在150 nm的B-f没有发现细胞毒性，而在有白蛋白存在的情况下，类似的B-f导致细胞活力下降40%，这表明细胞对UCB的总摄取在引起毒性效应中的重要性。在白蛋白结合的脐带血存在的情况下，无论白蛋白的来源、浓度或总胆红素水平如何，B-f法都可以准确地预测给定细胞系中胆红素诱导的细胞毒性。
Although it has been suggested that the unbound, free, (B-f) rather than total (B-T) bilirubin level correlates with cell toxicity, direct experimental evidence supporting this conclusion is limited. In addition, previous studies never included a direct measurement of Bf, using newer, accurate methods. To test "the free bilirubin hypothesis", in vitro cytotoxicity was assessed in four cell lines exposed to different Bf concentrations obtained by varying B-T/Albumin ratio, using serum albumins with different binding affinities, and/or displacing unconjugated bilirubin (UCB) from albumin with a sulphonamide. Bf was assessed by the modified, minimally diluted peroxidase method. Cytotoxicity varied among cell lines but was invariably related to B-f and not B-T. Light exposure decreased toxicity parallel to a decrease in B-f. In the absence of albumin, no cytotoxicity was found at a B-f of 150 nM whereas in the presence of albumin a similar B-f resulted in a 40% reduction of viability indicating the importance of total cellular uptake of UCB in eliciting toxic effect. In the presence of albumin-bound UCB, bilirubin-induced cytotoxicity in a given cell line is accurately predicted by B-f irrespective of the source and concentration of albumin, or total bilirubin level.