背景
　　心血管疾病多年蟬聯全球十大死因，臨床上治療心血管狹窄阻塞的手術主要為血管擴張術與血管繞道手術。血管繞道手術中的血管來源又可分為自體血管與人工血管，然而人工合成材料如鐵氟龍等在作為小直徑血管取代時通暢率極低，因此近年來組織工程血管(包含各種支架導向與自組裝細胞片)正蓬勃地發展。

目的
　　本篇研究的組織工程血管製備是將異物植入宿主體內引發異體反應，使得細胞外基質包覆住植入物而得生物膜管。然而根據之前的文獻，此種生物膜管的製備時間至少需要四個禮拜，因此我們利用聚乳酸不織布作為植入物，再加上血小板濃厚液中的生長因子刺激，期望能在短時間內製備出具備足夠機械強度與組織結構的生物膜管。而為了生物膜管在血管取代後能達到更好的血管重塑效果，我們在生物膜管上種植來自脂肪組織的血管基質部分，期望血管基質部分中幹細胞能分化為內皮細胞與平滑肌細胞，並且減少體外培養幹細胞所需耗費的時間。

材料與方法
　　將聚乳酸不織布捲起作為一直徑2毫米的雙層支架，而後將聚乳酸支架浸泡至活化的血小板濃厚液中並植入至紐西蘭大白兔背部皮下，兩週後取出。接著利用反覆冷凍解凍循環與低濃度十二烷基硫酸鈉溶液去除生物膜管的細胞，取代前再將新鮮萃取的血管基質部分種植上去細胞後的生物膜管，隔夜培養後將人工血管取代至大白兔的頸動脈，一個月後進行通暢率觀察與切片染色分析。

結果
　　第一個部分為比較去細胞前後的生物膜管，去細胞後的生物膜管其強度雖有些微下降，但是大致上並無顯著差異，而切片染色圖則顯示去細胞後的生物膜管其細胞已被大致清除且其細胞外基質的結構仍被保留。第二部分為比較有無種植血管基質部分的差異，在經過一個月後的頸動脈取代後，有種植血管基質部分的人工血管都維持暢通且其血管重建的效果較好，包括了更多新生的內皮細胞與平滑肌細胞表現量，另外雙重染色的結果則顯示血管基質部分的細胞在一個月後仍保持活性且有往內皮細胞及平滑肌細胞分化的現象。

結論
　　透過結合聚乳酸不織布與血小板濃厚液的刺激，我們成功地加速了自體組織工程血管的製備時間，另外此生物膜管也具有足夠的機械強度與完整的組織包覆。而在經過一個月的血管取代後，有種植血管基質部分的血管比起對照組表現出更佳的血管化，因此證明血管基質部分中的細胞的確是有助於血管的重塑。

Background
　　Cardiovascular disease (CVD) has been the major cause of death all over the world. Vascular angioplasty and vascular bypass surgery have been the main methods in treatment of CVD and autologous graft and synthetic material graft serve as the most common vascular grafts for bypass surgery. However, synthetic material grafts like Teflon show poor patency in small diameter vascular graft. Therefore, tissue engineered vascular graft (TEVG) including scaffold guided graft and self-assembly cell sheet have been widely investigated in the past years.

Objective
　　In this study, “biotube”, which is formed by inducing foreign body reaction in host body served as the TEVG. However, it took at least 4 weeks to harvest biotube in previous studies, which might not meet the urgent need. Therefore, we combine biodegradable nonwoven polylactic acid (PLA) mesh and platelet rich plasma (PRP) to accelerate the fabrication. Moreover, stromal vascular fraction (SVF), freshly isolated mixture of cells from adipose tissue, was seeded onto graft to improve vascular remodeling and reduce cell expansion and culture in vitro.

Methods
　　Nonwoven PLA was rolled into 2-layer tubular scaffold (diameter: 2mm) and then immersed into activated PRP solution to form PLA/PRP scaffold. PLA/PRP scaffolds were implanted into dorsal subcutaneous of New Zealand white rabbit for 2 weeks to obtain biotube. Harvested biotube was then treated with freeze-thawing cycles and sodium lauryl sulfate to achieve decellularization. SVF was seeded onto decellularized biotube (D-biotue) before vascular bypass surgery in rabbit model. After 1 month of implantation, patency was assessed by ultrasound and vascular remodeling was evaluated by histological and immunofluorescence staining.

Results
　　Although mechanical properties of D-biotube have slightly decreased, no significant difference was observed. The histological staining indicated that most of nuclei have been depleted while ECM structure was preserved. After 1 month of implantation, all SVF-seeded grafts remained patent. Neo-endothelium was detected and larger amount of smooth muscle cells (SMCs) were observed in SVF-seeded grafts compared to D-biotube. Cell trackers suggested that cells in SVF remained viable and stem cells in SVF might differentiate into ECs and SMCs.

Conclusion
　　This study suggests that the combination of nonwoven PLA and PRP stimulation reduce the fabrication time of autologous TEVG. Moreover, freshly isolated SVF seeded onto grafts has improved vascular remodeling compared to control grafts after 1 month of implantation.

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