title: Secretion of intestinal goblet cells: a novel excretion pathway of nanoparticles.
abstract: Understanding the excretion pathway is one of the most important prerequisites for the safe use of nanoparticles in biomedicine. However, the excretion of nanoparticles in animals remains largely unknown, except for some particles very small in size. Here we report a novel natural pathway for nanoparticle excretion, the intestinal goblet cell (GC) secretion pathway (IGCSP). Direct live observation of the behavior of 30-200nm activated carbon nanoparticles (ACNP) demonstrated that ACNP microinjected into the yolk sac of zebrafish can be excreted directly through intestinal tract without involving the hepato-biliary (hap-bile) system. Histopathological examination in mice after ligation of the common bile duct (CBD) demonstrated that the intravenously-injected ACNP were excreted into the gut lumen through the secretion of intestinal GCs. ACNP in various secretion phases were revealed by histopathological examination and transmission electron microscopy (TEM). IGCSP, in combination with renal and hap-bile pathways, constitutes a complete nanoparticle excretion mechanism.
  
  
  BACKGROUND
  Nanoparticle elimination pathways are in the forefront of interest in an effort to optimize and enable nanomedicine applications. This team of authors reports a novel natural pathway for nanoparticle excretion, the intestinal goblet cell (GC) secretion pathway (IGCSP). Direct live observation of the behavior of activated carbon nanoparticles has shown excretion directly through the intestinal tract without involving the hepato-biliary (hap-bile) system in a zebrafish model.
authors.affiliation: Institute of Pharmacology and Toxicology and Key Laboratory of Nanopharmacology and NanoToxicology, Beijing Academy of Medical Sciences, Beijing, China.
authors.forename: Baoquan
authors.initials: B
authors.lastname: Zhao
authors.affiliation: Institute of Pharmacology and Toxicology and Key Laboratory of Nanopharmacology and NanoToxicology, Beijing Academy of Medical Sciences, Beijing, China.
authors.forename: Lan
authors.initials: L
authors.lastname: Sun
authors.affiliation: Institute of Pharmacology and Toxicology and Key Laboratory of Nanopharmacology and NanoToxicology, Beijing Academy of Medical Sciences, Beijing, China; School of Pharmacy; and Nanotechnology Research Center for Drugs; Zhengzhou University, Zhengzhou, China.
authors.forename: Wuxu
authors.initials: W
authors.lastname: Zhang
authors.affiliation: Institute of Pharmacology and Toxicology and Key Laboratory of Nanopharmacology and NanoToxicology, Beijing Academy of Medical Sciences, Beijing, China.
authors.forename: Yuxia
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Hangzhou Hunter Biotechnology Incorporation, Hangzhou, China.
authors.forename: Junjing
authors.initials: J
authors.lastname: Zhu
authors.affiliation: Hangzhou Hunter Biotechnology Incorporation, Hangzhou, China.
authors.forename: Xiaoyu
authors.initials: X
authors.lastname: Zhu
authors.affiliation: Institute of Pharmacology and Toxicology and Key Laboratory of Nanopharmacology and NanoToxicology, Beijing Academy of Medical Sciences, Beijing, China.
authors.forename: Liuzhong
authors.initials: L
authors.lastname: Yang
authors.affiliation: Hangzhou Hunter Biotechnology Incorporation, Hangzhou, China.
authors.forename: Chunqi
authors.initials: C
authors.lastname: Li
authors.affiliation: School of Pharmacy; and Nanotechnology Research Center for Drugs; Zhengzhou University, Zhengzhou, China.
authors.forename: Zhenzhong
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Institute of Pharmacology and Toxicology and Key Laboratory of Nanopharmacology and NanoToxicology, Beijing Academy of Medical Sciences, Beijing, China. Electronic address: zhangygm@126.com.
authors.forename: Yingge
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D000818:Animals; D001652:Bile Ducts / Q000166:cytology / Q000378:metabolism; D020397:Goblet Cells / Q000166:cytology / Q000378:metabolism*; D008099:Liver / Q000166:cytology / Q000378:metabolism; D051379:Mice; D053758:Nanoparticles; D055571:Secretory Pathway; D015017:Yolk Sac / Q000166:cytology / Q000378:metabolism; D015027:Zebrafish
keywords: Aggregation; Excretion; Goblet cell; Nanoparticle; Pathway