~Teachingcenter的醫學筆記~

塑膠微粒(microplastics)對健康可能的危害

主要找到了兩篇最近的研究，分別是

1. An assessment of the toxicity of polypropylene microplastics in human derived cells
   刊於Science of Total Environmental (Sci Total Eviron.) Impact factor約4分多
   DOI: 10.1016/j.scitotenv.2019.05.071
2. Uptake and effects of orally ingested polystyrene microplastic particles in vitro and in vivo.
   刊於Archives of Toxicology (Arch Toxicol.) Impact factor約5分多
   DOI: 10.1007/s00204-019-02478-7

第一篇的摘要(abstract)
Environmental pollution caused by plastic waste is a growing global problem. Discarded plastic products and debris (microplastic particles) in the oceans detrimentally affect marine ecosystems and may impact human. Humans are exposed to plastic debris via the consumption of seafood and drinking water, contact with food packaging, or inhalation of particles. The accumulation of microplastic particles in humans has potential health risks such as cytotoxicity, hypersensitivity, unwanted immune response, and acute response like hemolysis. We investigated the cellular responses of secondary polypropylene microplastics (PP particles) of approximately ~20 μm and 25-200 μm in different condition and size to normal cells, immune cells, blood cells, and murine immune cells by cytokine analysis, ROS assay, polarization assay and proliferation assay. We found that PP particles showed low cytotoxicity effect in size and concentration manner, however, a high concentration, small sized, DMSO method of PP particles stimulated the immune system and enhanced potential hypersensitivity to PP particles via an increase in the levels of cytokines and histamines in PBMCs, Raw 264.7 and HMC-1 cells.
簡單的來說，這個研究是拿不同種的人類或老鼠細胞，在實驗室的環境下，泡在含有聚丙烯(PP)的培養液後，看看會有什麼結果，而結果就是在20~200 μm的大小差異，並不影響塑膠微粒對細胞的毒性，而塑膠微粒對細胞造成的影響，作者主要認為是和細胞激素(cytokines)和組織胺(histamines)有關
Cytokines可以進一步看
http://teachingcenter1.pixnet.net/blog/post/353983736
http://teachingcenter1.pixnet.net/blog/post/354291875
http://teachingcenter1.pixnet.net/blog/post/354269966
http://teachingcenter1.pixnet.net/blog/post/354269966
http://teachingcenter1.pixnet.net/blog/post/354005138
 

第二篇的摘要(abstract)
Evidence exists that humans are exposed to plastic microparticles via diet. Data on intestinal particle uptake and health-related effects resulting from microplastic exposure are scarce. Aim of the study was to analyze the uptake and effects of microplastic particles in human in vitro systems and in rodents in vivo. The gastrointestinal uptake of microplastics was studied in vitro using the human intestinal epithelial cell line Caco-2 and thereof-derived co-cultures mimicking intestinal M-cells and goblet cells. Different sizes of spherical fluorescent polystyrene (PS) particles (1, 4 and 10 µm) were used to study particle uptake and transport. A 28-days in vivo feeding study was conducted to analyze transport at the intestinal epithelium and oxidative stress response as a potential consequence of microplastic exposure. Male reporter gene mice were treated three times per week by oral gavage with a mixture of 1 µm (4.55 × 10⁷ particles), 4 µm (4.55 × 10⁷ particles) and 10 µm (1.49 × 10⁶ particles) microplastics at a volume of 10 mL/kg/bw. Effects of particles on macrophage polarization were investigated using the human cell line THP-1 to detect a possible impact on intestinal immune cells. Altogether, the results of the study demonstrate the cellular uptake of a minor fraction of particles. In vivo data show the absence of histologically detectable lesions and inflammatory responses. The particles did not interfere with the differentiation and activation of the human macrophage model. The present results suggest that oral exposure to PS microplastic particles under the chosen experimental conditions does not pose relevant acute health risks to mammals.
這篇研究的分數比較高~，做了兩個部分，實驗室中在容器裡泡塑膠微粒養細胞的做了(和前一個很類似，換成了PS)，另外還餵了實驗老鼠塑膠微粒，看看會發生甚麼事，嗯…可能是因為只餵了一個月(28天)，所以得到的結論只有”無急性健康風險”而已
感覺起來應該做個”累積”和”殘留”的實驗，”累積”簡單點就是要在做久一點再去觀察，一個月真的有點短，不過時間越久…也就越花錢就是了，而”殘留”的部分，就是清楚記錄吃下去多少塑膠微粒，排出多少塑膠微粒，去觀察每次的攝入，會有多少的殘留

※PP：Polypropylene聚丙烯

※PS：Polystyrene聚苯乙烯

雖然目前大部分的結論，都是傾向”無立即、急性危害”，但是塑膠微粒進到身體裡，就可能被吸收或卡在消化道裡，再加上又分解不掉，反正對人體而言，不是個好東西就是了~