Perrone R D
J Clin Invest. 1985 Oct;76(4):1688-91. doi: 10.1172/JCI112155.
It is thought that cysts in polycystic kidneys originate from nephron segments and function in a manner similar to the segment or origin. The indirect evidence for this derives from studies of microanatomy and cyst fluid composition. Cysts with low Na+ have been classified as distal, whereas cysts with high Na+ have been classified as proximal. In order to directly determine the transport characteristics of cyst epithelium, cysts from a human polycystic kidney were studied in vitro using Ussing chamber techniques. Composition of cyst fluid was determined in parallel with these studies. Cysts with low Na+ (gradient cysts) demonstrate characteristics consistent with distal nephron origin including elevated potential difference (PD), short-circuit current (Isc), and low conductance. PD and Isc of gradient cysts were amiloride sensitive. Nongradient cysts, however, require additional characterization. At least two types of nongradient cysts were identified, one with characteristics consistent with proximal nephron origin and another apparently without function. These studies are the first direct evidence for active transport of cysts from human polycystic kidney and provide strong evidence to support the concept that cysts function in the same manner as the nephron segment of origin.
据认为，多囊肾中的囊肿起源于肾单位节段，并以与该节段或起源方式相似的方式发挥功能。对此的间接证据来自微观解剖学和囊液成分的研究。低钠囊肿被归类为远端囊肿，而高钠囊肿被归类为近端囊肿。为了直接确定囊肿上皮的转运特性，使用Ussing室技术在体外研究了来自人类多囊肾的囊肿。同时测定了囊液的成分。低钠囊肿（梯度囊肿）表现出与远端肾单位起源一致的特征，包括升高的电位差（PD）、短路电流（Isc）和低电导。梯度囊肿的PD和Isc对氨氯地平敏感。然而，非梯度囊肿需要进一步表征。至少鉴定出两种类型的非梯度囊肿，一种具有与近端肾单位起源一致的特征，另一种显然无功能。这些研究是人类多囊肾囊肿主动转运的首个直接证据，并为支持囊肿与起源肾单位节段以相同方式发挥功能这一概念提供了有力证据。
