Department of Nephrology, Radboud Institute for Health Sciences, Radboud University Medical Center, Nijmegen, The Netherlands.
Department of Nephrology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands.
PLoS One. 2022 Sep 22;17(9):e0274959. doi: 10.1371/journal.pone.0274959. eCollection 2022.
Recurrence of proteinuria after kidney transplantation in primary focal segmental glomerulosclerosis (FSGS) is unpredictable. Several putative circulating permeability factors (CPFs) have been suggested, but none have been validated. A clinically relevant experimental model is required that demonstrates the presence of CPF(s) in patient material, to study CPF(s) and possibly predict recurrence in patients. We aimed to develop a FSGS-prone Thy-1.1 transgenic mouse model with accelerated proteinuria after injection of samples from patients with FSGS. The Thy-1.1 transgene was backcrossed into 5 mouse strains. The age of onset and severity of spontaneous proteinuria varied between the different genetic backgrounds. 129X1/SvThy-1.1 and 129S2/SvPasThy-1.1 mice displayed proteinuria at 4 weeks, whereas Balb/cThy-1.1 and C57BL/6JThy-1.1 mice developed proteinuria from 6 weeks, and were used further. We determined the maximum protein dose that could be injected without causing protein overload in each background. Balb/cThy-1.1 and C57BL/6JThy-1.1 males and females were injected with presumably CPF-containing plasmapheresis effluent from 6 FSGS patients, which induced albuminuria particularly in Balb/cThy-1.1 males. Unfortunately, no response could be detected when using sera instead of plasmapheresis effluent, serum being more clinically relevant in the context of predicting FSGS recurrence. Considering the differences between responses elicited by serum and plasmapheresis effluent, simultaneously collected serum, plasma, and plasmapheresis effluent were tested. Whereas we could detect responses using a validated in vitro model, none of these presumably CPF-containing samples induced proteinuria in Balb/cThy-1.1 males. Thus, we have extensively tested the Thy-1.1 mouse model on different genetic backgrounds with proteinuria after injection of FSGS patient material as clinically relevant readout. The Balb/cThy-1.1 male mouse strain demonstrated the most promising results, but to detect CPF activity in FSGS serum e.g. prior to kidney transplantation, this strain clearly lacks sensitivity and is therefore not yet clinically applicable. It could, however, still be used as research tool to study CPFs in patient samples that did induce proteinuria.
在原发性局灶节段性肾小球硬化症（FSGS）患者中，肾移植后蛋白尿的复发是不可预测的。已经提出了几种潜在的循环通透性因子（CPF），但没有一种得到验证。需要一种临床相关的实验模型，该模型能够证明患者材料中存在 CPF（s），以研究 CPF（s）并可能预测患者的复发。我们旨在开发一种 FSGS 易感 Thy-1.1 转基因小鼠模型，该模型在注射 FSGS 患者样本后会加速蛋白尿的产生。Thy-1.1 转基因被回交至 5 种不同的小鼠品系中。不同遗传背景下，自发性蛋白尿的发病年龄和严重程度存在差异。129X1/SvThy-1.1 和 129S2/SvPasThy-1.1 小鼠在 4 周时出现蛋白尿，而 Balb/cThy-1.1 和 C57BL/6JThy-1.1 小鼠则在 6 周时出现蛋白尿，并进一步使用。我们确定了在每种背景下可以注射而不会导致蛋白过载的最大蛋白剂量。Balb/cThy-1.1 和 C57BL/6JThy-1.1 雄性和雌性小鼠接受了来自 6 名 FSGS 患者的含 CPF 的血浆置换流出物的注射，这导致白蛋白尿，尤其是在 Balb/cThy-1.1 雄性小鼠中。不幸的是，当使用血清而不是血浆置换流出物时，无法检测到反应，在预测 FSGS 复发的情况下，血清更具临床意义。考虑到血清和血浆置换流出物引起的反应之间的差异，同时测试了同时收集的血清、血浆和血浆置换流出物。虽然我们可以使用经过验证的体外模型检测到反应，但在 Balb/cThy-1.1 雄性小鼠中，没有一种含有潜在 CPF 的样本能诱导蛋白尿。因此，我们已经在不同遗传背景下用 FSGS 患者材料注射后作为临床相关读出物对 Thy-1.1 小鼠模型进行了广泛测试。Balb/cThy-1.1 雄性小鼠表现出最有希望的结果，但为了在肾移植前检测 FSGS 血清中的 CPF 活性，该品系显然缺乏敏感性，因此目前还不能临床应用。然而，它仍然可以用作研究工具，用于研究确实诱导蛋白尿的患者样本中的 CPFs。
