AMD3100 treatment attenuates pulmonary angiogenesis by reducing the c-kit (+) cells and its pro-angiogenic activity in CBDL rat lungs

Recent studies have shown that pulmonary angiogenesis is an important pathological process in the development of hepatopulmonary syndrome (HPS), and growing evidence has indicated that Stromal cell-derived factor 1/C-X-C chemokine receptor type 4 (SDF-1/CXCR4) axis is involved in pulmonary vascular disease by mediating the accumulation of c-kit + cells. This study aimed to test the effect of AMD3100, an antagonist of CXCR4, in HPS pulmonary angiogenesis. Common bile duct ligation (CBDL) rats were used as experimental HPS model and were treated with AMD3100 (1.25 mg/kg/day, i.p.) or 0.9% saline for 3 weeks. The sham rats underwent common bile duct exposure without ligation. The c-kit + cells accounts and its angiogenic-related functions, prosurvival signals, pulmonary angiogenesis and arterial oxygenation were analysed in these groups. Our results showed that pulmonary SDF-1/CXCR4, Akt, Erk and VEGF/VEGFR2 were significantly activated in CBDL rats, and the numbers of circulating and pulmonary c-kit + cells were increased in CBDL rats compared with control rats. Additionally, the angiogenic-related functions of c-kit + cells and pulmonary microvessel counts were also elevated in CBDL rats. CXCR4 inhibition reduced pulmonary c-kit + cells and microvessel counts and improved arterial oxygenation within 3 weeks in CBDL rats. The pulmonary prosurvival signals and pro-angiogenic activity of c-kit + cells were also down-regulated in AMD3100-treated rats. In conclusion, AMD3100 treatment attenuated pulmonary angiogenesis in CBDL rats and prevented the development of HPS via reductions in pulmonary c-kit + cells and inhibition of the prosurvival signals. Our study provides new insights in HPS treatment.