Grantham J J, Uchic M, Cragoe E J, Kornhaus J, Grantham J A, Donoso V, Mangoo-Karim R, Evan A, McAteer J
Department of Medicine, University of Kansas School of Medicine, Kansas City.
Kidney Int. 1989 Jun;35(6):1379-89. doi: 10.1038/ki.1989.137.
We used an in vitro model, MDCK cyst, to determine the extent to which pharmacologic compounds known to inhibit plasma membrane solute transport mechanisms could alter the enlargement of renal epithelial cysts. Solitary MDCK cells cultured within collagen gel undergo clonal growth to form true epithelial cysts in which a single layer of polarized cells (apex toward lumen) encloses a fluid-filled cavity. Repeated observations by light microscopy were used to quantitate the rate of cyst growth in diameter, and demonstrated that cyst enlargement involved an increase in cell number (proliferation) and a net increase in intracystic volume (fluid secretion). Intracyst pressure was greater than the interstitium (6.7 mm H2O +/- 3.1 SD), indicating that fluid entry was secondary to net solute accumulation. Amiloride and seven amiloride analogs that inhibited to different degrees conductive Na+ transport, Na+-dependent H+ transport and Na+-dependent Ca++ transport reversibly decreased the rate of cyst enlargement. The effectiveness of these agents to retard cyst enlargement correlated with their relative potencies to inhibit Na+-dependent Ca++ transport. Morphologic examination indicated that amiloride and amiloride analogs decreased cell proliferation and fluid secretion to the same degree. Ouabain and vanadate (Na+K,ATPase inhibitors), and L-645,695 (Na+-dependent Cl-/HCO3- inhibitor) potently slowed cyst expansion. In contrast to amiloride and amiloride analogs, these agents caused an unusual degree of cellular stratification within the cyst walls, a finding consistent with the notion that fluid secretion was inhibited to a greater extent then cellular proliferation. We conclude that chemical inhibitors of primary and secondary active solute transport can diminish or halt the enlargement of epithelial cysts in vitro by decreasing the rate of cellular proliferation and/or net fluid secretion.
我们使用体外模型——MDCK囊肿，来确定已知可抑制质膜溶质转运机制的药物化合物能够在多大程度上改变肾上皮囊肿的增大。在胶原凝胶中培养的单个MDCK细胞经历克隆生长，形成真正的上皮囊肿，其中单层极化细胞（顶端朝向管腔）包围着一个充满液体的腔。通过光学显微镜的反复观察来定量囊肿直径的生长速率，并证明囊肿增大涉及细胞数量增加（增殖）和囊内体积净增加（液体分泌）。囊内压力大于间质压力（6.7毫米水柱±3.1标准差），表明液体进入是净溶质积累的继发结果。氨氯吡咪和七种氨氯吡咪类似物，它们不同程度地可逆抑制Na⁺传导性转运、Na⁺依赖性H⁺转运和Na⁺依赖性Ca²⁺转运，可降低囊肿增大速率。这些药物延缓囊肿增大的有效性与其抑制Na⁺依赖性Ca²⁺转运的相对效力相关。形态学检查表明，氨氯吡咪和氨氯吡咪类似物同等程度地降低细胞增殖和液体分泌。哇巴因和钒酸盐（Na⁺K,ATP酶抑制剂）以及L - 645,695（Na⁺依赖性Cl⁻/HCO₃⁻抑制剂）可有效减缓囊肿扩张。与氨氯吡咪和氨氯吡咪类似物不同，这些药物在囊肿壁内引起了异常程度的细胞分层，这一发现与液体分泌比细胞增殖受到更大程度抑制的观点一致。我们得出结论，一级和二级主动溶质转运的化学抑制剂可通过降低细胞增殖速率和/或净液体分泌，在体外减少或阻止上皮囊肿的增大。
