Abstract: TH-PO422

Homocysteine Aggravates Intestinal Permeability Increase and Tight Junction Destruction In Vivo and In Vitro

Session Information

Category: Nutrition, Inflammation, and Metabolism

  • 1401 Nutrition, Inflammation, Metabolism

Authors

  • Liang, Shanshan, Dialysis Department of Nephrology Hospital, First Affiliated Hospital of Medicine School, Xi?an Jiaotong University, Xi?an, China
  • Jiang, Hongli, Dialysis Department of Nephrology Hospital, First Affiliated Hospital of Medicine School, Xi?an Jiaotong University, Xi?an, China
Background

Intestinal injury is a common complication of uremia. Homocysteine (Hcy), as an important intestinal derived uremic toxin and pro-inflammatory molecule, whether it is involved in the increased intestinal permeability and epithelial barrier dysfunction in uremia remains unclear. This study aimed to investigate the effect of Hcy on intestinal epithelial in vitro and in vivo.

Methods

In vitro experiment, Caco2 cells were seeded on transwell plates and utilized when transepithelial electrical resistance (TEER) exceeded 500Ω*cm2 to ensure full polarization and TJ formation. Cells were then incubated with Hcy (0.5 to 5.0mmol/L) for 24h. Paracellular permeability was determined by TEER and the fluorescent Lucifer yellow dye (FLY) flux across cell monolayers. In vivo experiment, SD rats were divided into control, uremia (induced by adenine) and uremia + vitamin B compounds (folate, vitamin B6 and B12) group. Serum Hcy levels, colon homogenate of Hcy, inflammatory factors (CRP, IL-6 and TNF-α), SOD, MDA, endotoxin and intestinal permeability were assessed. H&E and transmission electron microscopy were used for pathological analysis. TJ proteins of claudin-1, occludin, and ZO-1 were assessed by western blot.

Results

Fig.1 showed the TEER changes of Caco-2 cells during 21 days and the decreased TEER as well as the gradually increased FLY flux rates after Hcy incubation. Hcy down regulates TJ protein abundance in a concentration-dependent manner (Fig 4A), which was accompanied with the increased epithelial permeability. In animal experiments, uremia group showed elevated Hcy levels, oxidized inflammatory factors and intestinal permeability (Fig 2). The pathological changes of colon were obviously observed (Fig 3) with TJ protein levels decreased (Fig 4B). Fortunately, these parameters were improved in varying degrees after vitamin B compounds treatment.

Conclusion

Hcy aggravates intestinal permeability increase and epithelial barrier destruction by stimulating oxidative inflammatory damage. Supplementation of folate, vitamin B6 and B12 can improve the damage to some extent by reducing Hcy.

Funding

  • Government Support - Non-U.S.