See Article on Pages 648–662
In spite of plausible biological mechanisms, the impacts of air pollution on kidney disease have been relatively less studied than those for cardiovascular, respiratory, and mental diseases [1]. A small but growing body of epidemiological literature has investigated the impacts of exposures to particulate matter on various renal outcomes including a renal function decrease [2], an incidence of end-stage kidney disease [2], and hospitalization due to acute kidney injury [3,4]. These epidemiologic papers have consistently reported the hazardous impacts of inhaled particulate matter through large cohort data, with plausible pathways (Fig. 1). They also considered ambient particulate matter concentrations based on the addresses of participants as an exposure, because it was nearly impossible to measure the “true” particulate matter exposure amounts. Thus, regarding these studies, potential biases from measurement error and hidden confounders have been suggested, and in order to redeem them, experimental studies have been required.
In addition, most previous studies addressed the elderly population as their study population. Although a decrease in renal function is closely related to aging [5], it does not indicate the non-elderly populations are not at-risk populations against air pollution and kidney diseases: a previous study in South Korea based on the health insurance claim data reported that the excess emergency room visits were higher in people aged 0 to 64 years than in those of people aged 65 years or older. Further, recently, a question on the impacts of perinatal exposure to particulate matter on kidney function has arisen from epidemiological studies. A recent birth cohort study has reported that particulate matter exposure between 1 and 8 gestational weeks was associated with preadolescent estimated glomerular filtration rate [6]. Nevertheless, still, studies on the relationship between maternal exposure to particulate matter and kidney function parameters are less investigated and the relevant experimental studies are much scarcer.
The paper by Son et al. [7], which identified that maternal particulate matter exposure increases glomerular damage, tubulointerstitial injury, and cortical macrophage infiltration in rat dams and their male offspring through a laboratory examination, is an important advance in this area. The authors found that maternal exposure to particulate matter during nephrogenesis induces renal injury in both dams and pups, which is related to disturbances of vitamin D signaling and the renin-angiotensin system. They also revealed that glomerular and tubular injury, oxidative stress, and inflammation increased in the kidneys from both dams and pups due to maternal exposure to particulate matter, and the impacts of particulate matter were reduced by maternal vitamin D intake.
Their results are generally aligned with previous findings from relevant experimental studies. Previous laboratory studies showed that inhaled air pollutants bring biological damage to kidney tissue [8,9]. In particular, a previous animal model study identified that prolonged pulmonary exposure to diesel exhaust particles—which are major fractions of particulate matter—is related to deterioration in renal oxidative stress, inflammation, and DNA damage in mice with adenine-induced chronic renal failure [10]. Nevertheless, Son et al.’s study [7] has major scientific significance in that it demonstrated the impacts of particulate matter during pregnancy and the interventional roles of vitamin D at the laboratory stage, which have been rarely studied so far.
In conclusion, Son et al.’s study [7] makes an important contribution to the scholarship on the association between maternal exposure to particulate matter and kidney function, along with the potential roles of vitamin D intake as a moderator. This study also implies the appropriateness and necessity of large data-based epidemiological and/or clinical studies that can start to improve our knowledge towards better kidney health from the perspective of environmental health.
PDF Links
PubReader
ePub Link
XML Download
Full text via DOI
Download Citation
Print
