Supplementary Material for: Endothelial Dysfunction Occurs prior to Clinical Evidence of Polycystic Kidney Disease

Objective: Polycystic kidney disease (PKD), a monogenic disease with an autosomal dominant or an autosomal recessive form of inheritance (ARPKD), is the most common genetic cause of renal dysfunction and end-stage renal failure. In addition to the development of cysts, the autosomal form of PKD is associated with vascular endothelial dysfunction, a marker of vascular disease. Whether vascular endothelial dysfunction is also present in ARPKD, and its relationship with renal dysfunction remain to be determined. Methods: ARPKD rats (PCK model) and controls were studied at 6 and 10 weeks of age, and mean arterial pressure and renal function were measured. Aortic endothelial function was assessed using organ chamber techniques. Aortic endothelial cells (ECs) were isolated, characterized and their function studied. Results: Compared to controls, ARPKD animals had a decrease in the vasorelaxation to endothelium-dependent vasodilators, even prior to changes in mean arterial pressure or renal function. The abnormal vasoreactivity was corrected with L-arginine (a precursor of nitric oxide, NO), while the expression of endothelial NO synthase (eNOS) was unchanged. Furthermore, isolated ECs from 6-week-old ARPKD animals showed increased oxidative stress, with preserved eNOS expression and abnormal patterns of migration and angiogenic capacity (measured by the scratch and tube formation assays, respectively). Conclusion: ARPKD leads to impairments in aortic vascular function and ECs at an early stage, which can have significant functional consequences, potentially representing a novel therapeutic target in this disease.

研究目的：多囊肾疾病（Polycystic kidney disease, PKD）是一类单基因遗传病，可呈常染色体显性或常染色体隐性遗传（ARPKD），是引发肾功能不全与终末期肾衰竭的最常见遗传病因。除囊肿形成外，常染色体显性型PKD与血管内皮功能障碍相关，而后者是血管疾病的标志性指标。目前尚不清楚ARPKD中是否同样存在血管内皮功能障碍，以及其与肾功能不全的关联机制。
研究方法：本研究以ARPKD大鼠（PCK模型）及对照大鼠为研究对象，分别在6周龄与10周龄时开展实验，检测平均动脉压与肾功能指标。采用器官槽技术评估主动脉内皮功能。分离主动脉内皮细胞（endothelial cells, ECs）并对其进行鉴定，同时开展功能学研究。
研究结果：与对照组相比，ARPKD模型动物对内皮依赖性血管舒张剂的血管舒张反应出现减弱，且该变化甚至早于平均动脉压或肾功能的异常改变。这种异常血管反应可通过L-精氨酸（一氧化氮（nitric oxide, NO）前体）得到纠正，而内皮型一氧化氮合酶（endothelial NO synthase, eNOS）的表达水平未发生变化。进一步研究发现，6周龄ARPKD模型动物分离得到的内皮细胞（ECs）氧化应激水平升高，内皮型一氧化氮合酶表达得以保留，但迁移能力与血管生成能力出现异常（分别通过划痕实验与管形成实验进行检测）。
研究结论：ARPKD可在疾病早期即造成主动脉血管功能与内皮细胞功能损伤，该损伤具有显著的功能学意义，有望成为该疾病的新型治疗靶点。