Fc 107snf472 Attenuates the Progression of Femoral Artery Calcification and Recovers Limb Blood Perfusion and Walking Ability in a Rat Model of Peripheral Artery Disease

Abstract

Background and Aims Peripheral artery disease (PAD) is a common co-morbidity in end-stage kidney disease (ESKD) patients undergoing dialysis. The prominent vascular calcification in these patients is associated with severity of symptoms and adverse outcomes. Although there are medical therapies approved for PAD, none of them has been specifically approved por PAD-ESKD. For example, cilostazol is approved for PAD but its use is limited in PAD-ESKD patients. Surgical interventions are challenging in these patients due to their specific vascular calcification and show worse outcomes. Therefore, the aims of this study were to evaluate the effects of the investigational drug SNF472, a selective inhibitor of vascular calcification, on blood perfusion and limb functional recovery in a Vitamin D3 (VitD)-induced rat model of arterial calcification and limb ischemia. Method Three consecutives daily subcutaneous (s.c) doses of VitD were administered to 66 male Sprague Dawley rats to induce limb ischemia. Rats were randomized into four groups at day 5 after the start of VitD treatment (when all parameters were measured in a satellite group) and were treated for nine days with placebo s.c., placebo peroral (p.o.), SNF472 (40 mg/kg/day, s.c.) or cilostazol (40 mg/kg/day, p.o.). An additional control group did not receive VitD (sham) and was administered with placebo s.c. during these last nine days. Posterior limb blood perfusion was measured using laser Doppler imaging at baseline (before calcification induction), day 4 (before treatment start) and day 13 (end of treatment). Walking ability was evaluated by measuring Maximum Walking Distance (MWD) and Maximum Walking Time (MWT) using a rat treadmill at baseline, day 4 and day 11. Rats were sacrificed at day 13, and heart and femoral arteries were collected for calcium analysis. Results Administration of VitD induced heart and femoral artery calcification by day 5. This calcification was associated with decreased limb blood perfusion and impairment of walking ability (both MWT and MWD) compared to sham. Treatment with SNF472 inhibited calcification progression in femoral arteries by 41% and in heart by 56% compared to placebo. The inhibition of calcification progression by SNF472 led to a 29% increase in limb blood perfusion (p< 0.001) and a significant improvement in walking ability (49% in MWD and 43% in MWT; p< 0.05) compared to placebo. Calcification inhibition in femoral arteries was positively correlated with both MWD and MWT (p< 0.0001). No effects of cilostazol were observed in tissue calcification, limb blood perfusion or walking ability. Conclusion SNF472 attenuates the progression of vascular calcification and improves blood perfusion and the functional parameters MWT and MWD in a rat model of PAD vascular calcification. These results support investigation of SNF472 as a potential therapy for PAD-ESKD patients who have vascular dysfunction due to a high degree of arterial calcification.