3B´s Research Group-Biomaterials, Biodegradables and Biomimetics, University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, AvePark, Barco, 4805-017, Guimarães, Portugal.
ICVS/3B's-T Government Associate Laboratory, Braga/Guimarães, Portugal.
World J Urol. 2018 Feb;36(2):277-283. doi: 10.1007/s00345-017-2124-3. Epub 2017 Nov 11.
To perform an in vivo assessment of a newly developed biodegradable ureteral stent (BUS) produced with natural-based polymers.
The BUS is based on a patented technology combining the injection process with the use of supercritical fluid technology. Study was conducted at ICVS-University of Minho (Braga, Portugal) and a total of ten domestic pigs were used. In seven animals, the experimental BUS stent was inserted, whereas in the remaining a commercially available stent was used (6-Fr Biosoft duo stents, Porges Coloplast, Denmark). Post-stenting intravenous pyelogram was used to evaluate the degree of hydronephrosis. The in vivo stent degradation was measured as function of the weight loss. Moreover, the tensile properties of the BUS were tested during in vivo degradation. After maximum 10 days, animals were killed and necropsy was performed. Tissues were compared between the stented groups as well as between the non-stented contralateral ureters and stented ureters in each group. Biocompatibility was assessed by histopathological grading.
In all cases, the BUS was only visible during the first 24 h on X-ray, and in all cases the BUS was completely degraded in urine after 10 days, as confirmed on necropsy. During the degradation process, the mechanical properties of the BUS decreased, while the commercial ureteral stents remained constant. At all time-points after stent insertion, the level of hydronephrosis was minimal. Overall, animals stented with BUS had an average grade of hydronephrosis which was lower compared to the controls. The BUS showed better pathological conditions, and hence better biocompatibility when compared with commercial stents.
Notwithstanding the limitations of the present study, the in vivo testing of our novel natural origin polymer-based BUS suggests this device to feature homogeneous degradation, good urine drainage, and high biocompatibility. Next steps will be to increase its stability, and to improve the radiopacity without compromising its degradation. Ultimately, clinical studies will be required to determine the safety and feasibility of its use in humans.
对一种新开发的基于天然聚合物的可生物降解输尿管支架（BUS）进行体内评估。
BUS 基于一种专利技术，结合了注塑工艺和超临界流体技术的使用。该研究在 ICVS-University of Minho（葡萄牙布拉加）进行，共使用了 10 头家猪。在 7 只动物中插入了实验性 BUS 支架，而在其余的动物中则使用了市售支架（6-Fr Biosoft duo 支架，Porges Coloplast，丹麦）。支架置入后行静脉肾盂造影术以评估肾盂积水程度。通过测量重量损失来评估体内支架降解程度。此外，还在体内降解过程中测试了 BUS 的拉伸性能。10 天后，动物被处死并进行尸检。比较支架组之间以及每组中未支架的对侧输尿管和支架输尿管之间的组织。通过组织病理学分级评估生物相容性。
在所有情况下，BUS 仅在 X 射线下可见 24 小时，在所有情况下，BUS 在 10 天后在尿液中完全降解，尸检时得到证实。在降解过程中，BUS 的机械性能下降，而商用输尿管支架保持不变。在支架置入后的所有时间点，肾盂积水程度均最小。总体而言，与对照组相比，使用 BUS 支架的动物平均肾盂积水程度较低。与商用支架相比，BUS 表现出更好的病理状况，因此具有更好的生物相容性。
尽管存在本研究的局限性，但我们新型天然来源聚合物基 BUS 的体内测试表明，该装置具有均匀降解、良好的尿液引流和高生物相容性的特点。下一步将提高其稳定性，并在不影响其降解的情况下提高其放射可检测性。最终，需要进行临床研究以确定其在人体中的安全性和可行性。
