Satarug Soisungwan
Kidney Disease Research Collaborative, Translational Research Institute, Woolloongabba, Brisbane, QLD 4102, Australia.
Biomedicines. 2024 Mar 23;12(4):718. doi: 10.3390/biomedicines12040718.
Cadmium (Cd) is a metal with no nutritional value or physiological role. However, it is found in the body of most people because it is a contaminant of nearly all food types and is readily absorbed. The body burden of Cd is determined principally by its intestinal absorption rate as there is no mechanism for its elimination. Most acquired Cd accumulates within the kidney tubular cells, where its levels increase through to the age of 50 years but decline thereafter due to its release into the urine as the injured tubular cells die. This is associated with progressive kidney disease, which is signified by a sustained decline in the estimated glomerular filtration rate (eGFR) and albuminuria. Generally, reductions in eGFR after Cd exposure are irreversible, and are likely to decline further towards kidney failure if exposure persists. There is no evidence that the elimination of current environmental exposure can reverse these effects and no theoretical reason to believe that such a reversal is possible. This review aims to provide an update on urinary and blood Cd levels that were found to be associated with GFR loss and albuminuria in the general populations. A special emphasis is placed on the mechanisms underlying albumin excretion in Cd-exposed persons, and for an accurate measure of the doses-response relationships between Cd exposure and eGFR, its excretion rate must be normalised to creatinine clearance. The difficult challenge of establishing realistic Cd exposure guidelines such that human health is protected, is discussed.
镉(Cd)是一种没有营养价值或生理作用的金属。然而,它存在于大多数人的体内,因为它是几乎所有食物类型的污染物,且易于被吸收。镉的体内负荷主要由其肠道吸收率决定,因为人体没有清除镉的机制。大多数后天摄入的镉会在肾小管细胞内蓄积,其含量在50岁之前会不断增加,但此后会因受损的肾小管细胞死亡并释放到尿液中而下降。这与进行性肾脏疾病相关,其表现为估计肾小球滤过率(eGFR)持续下降和蛋白尿。一般来说,镉暴露后eGFR的降低是不可逆的,如果持续暴露,eGFR可能会进一步下降直至肾衰竭。没有证据表明消除当前的环境暴露可以逆转这些影响,也没有理论依据认为这种逆转是可能的。本综述旨在提供关于一般人群中与肾小球滤过率降低和蛋白尿相关的尿镉和血镉水平的最新信息。特别强调了镉暴露人群中白蛋白排泄的潜在机制,为准确衡量镉暴露与eGFR之间的剂量反应关系,其排泄率必须根据肌酐清除率进行标准化。文中还讨论了制定切实可行的镉暴露指南以保护人类健康这一艰巨挑战。