title: Role of nanobacteria in the pathogenesis of kidney stone formation.
abstract: OBJECTIVE
  This study aimed to investigate the nanobacteria (NB) induced damage to human tubular epithelial HK-2 cells and the potential role of NB in the kidney stone formation.
  
  
  METHODS
  Serum sample from 15 patients with kidney stone was collected. Four groups were included: control, NB group, nanograde hydroxyapatite (nHAP) and calcium oxalate monohydrate (COM) group. Catalase (CAT), malonaldehyde (MDA) and Na(+)/K(+) ATPase activity was detected in the supernatant at 12 and 24 h. At 12 and 24 h, COM was added.
  
  
  RESULTS
  At 12 h and 24 h, the CAT in NB group was significantly higher than in control group and nHAP group (P<0.01). CAT at 24 h was significantly higher than in COM group (P<0.01). At 12 h and 24 h, the MDA in NB group was significantly higher than in control group and nHAP group (P<0.01) and significantly lower than in COM group (P<0.01). At 12 h, the Na(+)/K(+) ATPase activity in NB group and nHAP group was significantly lower than in control group, but dramatically increased as compared to COM group (P<0.01). At 24 h, the Na(+)/K(+) ATPase activity in NB group and nHAP group was significantly lower than in control group (P<0.01).
  
  
  CONCLUSIONS
  NB may induce lipid peroxidation in HK-2 cells and cause adhesion of HK-2 cells to COM in a time-dependent manner, resulting in damage to HK-2 cells. This injury-causing capability of NB is more potent than nHAP and might be involved in the pathogenesis of kidney stone formation.
authors: Department of Urology, Peking University International Hospital Beijing 102206, China.
authors: Xin
authors: X
authors: Hong
authors: Department of Urology, Peking University International Hospital Beijing 102206, China.
authors: Xiaofeng
authors: X
authors: Wang
authors: Department of Urology, Peking University International Hospital Beijing 102206, China.
authors: Tian
authors: T
authors: Wang
authors: Department of Urology, Peking University International Hospital Beijing 102206, China.
authors: Chengfan
authors: C
authors: Yu
authors: Department of Urology, Peking University International Hospital Beijing 102206, China.
authors: Hui
authors: H
authors: Li
keywords: HK-2 cells; Nanobacteria; calcium oxalate monohydrate; nanograde hydroxyapatite