探討臍帶及胎盤間質幹細胞來源的分泌體對次氯酸鈉誘導的腹膜纖維化之治療潛能

Abstract

腹膜透析是一種常用在末期腎臟病患者身上的腎臟替代療法，腹膜透析的原理是藉由腹膜的半通透性進行離子平衡的校正並移除多餘水分和廢物，然而，長期的腹膜透析會導致腹膜型態上及功能上的改變，甚至在最後引起腹膜纖維化的病變。為了解決這個問題，利用間質幹細胞來源的分泌體(secretome)做為治療選項的想法被提出及研究，之前的研究證實間質幹細胞來源的分泌成份可在囓齒類動物模型中，有效的減緩肺纖維化及肝臟纖維化的情形。在本研究中，我們以生技公司及合作實驗室獲得的臍帶(US)及胎盤(PS)間質幹細胞來源的分泌體作為研究目標，透過人類腹膜間皮細胞(MeT-5A)及三品種豬(藍瑞斯-約克夏-杜洛克)分別作為體外及體內實驗的平台，去探討臍帶間質幹細胞來源的分泌體之治療潛能;而胎盤間質幹細胞分泌體只以體外實驗結果探討其對於人類腹膜間皮細胞之影響。本次研究使用次氯酸鈉(NaClO)在細胞及動物實驗中來誘導腹膜纖維化產生。根據研究的結果，在細胞實驗中，加入US及PS不但對間皮細胞沒有毒殺姓，甚至還可以提升間皮細胞的細胞存活率，然而只有PS可以顯著的改善經過次氯酸鈉損傷後的細胞存活率。在次氯酸鈉誘導腹膜纖維化的豬模型中，US可以改善腹膜的小型溶質運輸能力及降低壁層腹膜組織的第一型膠原蛋白沉積；然而，間皮的完整性、纖維母細胞的積累及壁層和臟層腹膜組織表面的增厚並無法得到較好的改善，除此之外，在進行動物實驗的過程中，我們還發現四隻中有一個體於給予US後會有嚴重的過敏反應，顯示以未純化之幹細胞培養液直接用於治療須特別留意。在本論文中，給予臍帶(US)間質幹細胞來源的全分泌體並無法明顯改善次氯酸鈉誘導的腹膜纖維化情形，未來是否需進一步針對培養液進行分離與純化（例如分離外泌體exosomes）值得近一步研究。

Peritoneal dialysis (PD) is one kind of renal replacement therapy often used in end-stage renal disease (ESRD) patients. The principle of PD is to correct electrolyte imbalance and remove excess fluid and waste through the semi-permeable peritoneum. However, long-term PD will cause morphological and functional changes in the peritoneum, finally leading to peritoneal fibrosis. To solve this problem, using mesenchymal stem cells (MSCs)-derived secretome as a treatment was proposed and studied. Previous studies have already shown that the secretome component of MSC can attenuate the pulmonary fibrosis and liver fibrosis in the rodent model. In this study, secretomes from the umbilical cord (US) and placenta (PS) obtained from the company and a collaboration lab were used as treatment sources. Human peritoneal mesothelial cell line (MeT-5A) and LYD (Landrace-Yorkshire-Duroc) pigs were used as a platform to investigate the therapeutic potential of US in vitro and in vivo, whereas PS was only studied in vitro. To mimic the PF situation, NaClO was used to induce PF in both cell experiments and in the porcine model. According to the results in this study, US and PS addition can increase the cell viability without causing cytotoxicity on mesothelial cells, while only PS can significantly improve the cell viability after NaClO injury. In the NaClO porcine model, US application can improve the small solute transport capability of the peritoneum and decrease collagen I deposition on the parietal peritoneum. However, the mesothelium integrity, myofibroblast accumulation, and parietal and visceral peritoneum tissue thickness were not affected after the US application. Moreover, we found that after US administration, one of four pigs had an allergy reaction indicating caution is needed upon the usage of whole MSCs culture supernatant without purification. In conclusion, the complete US application did not show significant improvement in NaClO-induced PF porcine model in the current study; whether fractions of the US (e.g., exosomes) can result in better therapeutic outcomes require further investigation.