Kopytina Valeria, Pascual-Antón Lucía, Toggweiler Nora, Arriero-País Eva-María, Strahl Lisa, Albar-Vizcaíno Patricia, Sucunza David, Vaquero Juan J, Steppan Sonja, Piecha Dorothea, López-Cabrera Manuel, González-Mateo Guadalupe-Tirma
Department of Immunology, Molecular Biology Research Center Severo Ochoa (CBMSO), Spanish National Research Council (CSIC), Madrid, Spain.
Fresenius Medical Care Deutschland GmbH, Frankfurter, St. Wendel, Germany.
Front Pharmacol. 2022 Aug 16;13:868374. doi: 10.3389/fphar.2022.868374. eCollection 2022.
Peritoneal dialysis (PD) is a renal replacement technique that requires repeated exposure of the peritoneum to hyperosmolar PD fluids (PDFs). Unfortunately, it promotes alterations of the peritoneal membrane (PM) that affects its functionality, including mesothelial-mesenchymal transition (MMT) of mesothelial cells (MCs), inflammation, angiogenesis, and fibrosis. Glucose is the most used osmotic agent, but it is known to be at least partially responsible, together with its degradation products (GDP), for those changes. Therefore, there is a need for more biocompatible osmotic agents to better maintain the PM. Herein we evaluated the biocompatibility of Steviol glycosides (SG)-based fluids. The ultrafiltration and transport capacities of SG-containing and glucose-based fluids were analyzed using artificial membranes and an mouse model, respectively. To investigate the biocompatibility of the fluids, Met-5A and human omental peritoneal MCs (HOMCs) were exposed to different types of glucose-based PDFs (conventional 4.25% glucose solution with high-GDP level and biocompatible 2.3% glucose solution with low-GDP level), SG-based fluids or treated with TGF-β1. Mice submitted to surgery of intraperitoneal catheter insertion were treated for 40 days with SG- or glucose-based fluids. Peritoneal tissues were collected to determine thickness, MMT, angiogenesis, as well as peritoneal washings to analyze inflammation. Dialysis membrane experiments demonstrated that SG-based fluids at 1.5%, 1%, and 0.75% had a similar trend in weight gain, based on curve slope, as glucose-based fluids. Analyzing transport capacity , 1% and 0.75% SG-based fluid-exposed nephrectomized mice extracted a similar amount of urea as the glucose 2.3% group. , PDF with high-glucose (4.25%) and high-GDP content induced mesenchymal markers and angiogenic factors (Snail1, Fibronectin, VEGF-A, FGF-2) and downregulates the epithelial marker E-Cadherin. In contrast, exposition to low-glucose-based fluids with low-GDP content or SG-based fluids showed higher viability and had less MMT. SG-based fluids preserved MC monolayer, induced less PM thickness, angiogenesis, leukocyte infiltration, inflammatory cytokines release, and MMT compared with glucose-based fluids. SG showed better biocompatibility as an osmotic agent than glucose and , therefore, it could alternatively substitute glucose in PDF.
腹膜透析（PD）是一种肾脏替代技术，需要使腹膜反复接触高渗腹膜透析液（PDFs）。不幸的是，这会促使腹膜（PM）发生改变，进而影响其功能，包括间皮细胞（MCs）的间皮-间充质转化（MMT）、炎症、血管生成和纤维化。葡萄糖是最常用的渗透剂，但已知它与其降解产物（GDP）至少要对这些变化承担部分责任。因此，需要更具生物相容性的渗透剂来更好地维持腹膜。在此，我们评估了基于甜菊糖苷（SG）的透析液的生物相容性。分别使用人工膜和小鼠模型分析了含SG的透析液和基于葡萄糖的透析液的超滤和转运能力。为了研究透析液的生物相容性，将Met-5A和人网膜腹膜间皮细胞（HOMCs）暴露于不同类型的基于葡萄糖的PDFs（高GDP水平的传统4.25%葡萄糖溶液和低GDP水平的生物相容性2.3%葡萄糖溶液）、基于SG的透析液或用转化生长因子-β1处理。接受腹膜内导管插入手术的小鼠用基于SG或葡萄糖的透析液治疗40天。收集腹膜组织以确定厚度、MMT、血管生成情况，并收集腹膜冲洗液以分析炎症。透析膜实验表明，基于曲线斜率，1.5%、1%和0.75%的基于SG的透析液在重量增加方面与基于葡萄糖的透析液有相似趋势。分析转运能力，暴露于1%和0.75%基于SG的透析液的肾切除小鼠提取的尿素量与2.3%葡萄糖组相似。高葡萄糖（4.25%）和高GDP含量的PDF诱导间充质标志物和血管生成因子（Snail1、纤连蛋白、血管内皮生长因子-A、成纤维细胞生长因子-2），并下调上皮标志物E-钙黏蛋白。相反，暴露于低GDP含量的低葡萄糖基透析液或基于SG的透析液显示出更高的活力且MMT较少。与基于葡萄糖的透析液相比，基于SG的透析液保留了MC单层，诱导的腹膜厚度、血管生成、白细胞浸润、炎性细胞因子释放和MMT更少。作为渗透剂，SG显示出比葡萄糖更好的生物相容性，因此，它可以替代PDF中的葡萄糖。
