Uruguayan experience with cryopreserved arterial homografts

Demography and Outcomes of Arteriovenous Fistula: Challenges and Future Directions

The incidence and prevalence rates of treated end-stage kidney disease (ESKD) patients are on the rise worldwide. Hemodialysis remains the main modality of providing renal replacement therapy for the ESKD patients, and the preferred vascular access is an arteriovenous fistula (AVF). The objective is to assess the patency rates and primary failures of the AVF. All patients who attended the Royal Hospital in Muscat, Oman, from January 2010 to December 2014 for AVF creation were included in this study. Data were extracted from the hospital's electronic medical record system where data are entered prospectively. During the period of study from 2010 to 2014, 465 primary fistulae were created in 427 patients. The mean age of the patient was 58 years. Only 6% needed general anesthesia, while the rest were done under regional or local anesthesia. Fifty-one percent of the patients were diabetic. Preemptive AVF was constructed in only 12% of patients. Most cases (47%) had left brachiocephalic (BC) fistulae. The left radiocephalic (RC) fistulae constituted 25.7% and the left brachiobasilic fistulae 9.9%. The remaining were constructed in the right upper limb. The total patency was achieved in 80% of fistulae and the failure rate was 20% at 6 months. Whereas, at 12 months, the total patency rate was 71% and the failure rate was 29%. Thus, we can conclude that more than 50% of patients, half of them being females, were diabetics. This resulted in more fistulae being constructed in the arm, namely left BC fistulae and left RC fistulae. Furthermore, it is important to note that only a very small percentage of patients had an established preemptive AVF. These factors may be responsible for a failure rate of 20% and 29% of the AVFs at 6 months and 12 months, respectively.

Recellularization potential assessment of Wharton's Jelly-derived endothelial progenitor cells using a human fetal vascular tissue model

Mesenchymal stem cells isolated from Wharton's Jelly have demonstrated an excellent differentiation potential into the endothelial lineage. We hypothesize that endothelial progenitor cells differentiated from Wharton's Jelly-derived mesenchymal stem cells have the potential to repopulate a decellularized vascular bed employed as a biological scaffold. For this purpose, we aimed at investigating the behavior of the endothelial progenitor cells in the decellularized matrix and their potential to repopulate decellularized human vascular tissue. Our main objectives were to differentiate Wharton's Jelly-derived mesenchymal stem cells into endothelial progenitor cells and to obtain a human vascular tissue slice experimental model using the umbilical cord arteries. We employed a decellularization method using enzymatic treatment of the umbilical cord arteries and a recellularization method with the endothelial progenitor cells differentiated from Wharton's Jelly mesenchymal cells in a co-culture system, in order to investigate our hypothesis. The cellular integration within the biological scaffold was determined by using flow cytometry analysis and confirmed by visualization of histological staining as well as fluorescence microscopy. The morphological observations of the recellularized scaffolds revealed the presence of endothelial progenitor cells within the decellularized tissue slices, displaying no degradation of the scaffold's extracellular matrix. The flow cytometry analysis revealed the presence of Wharton's Jelly-derived endothelial progenitor cells population in the decellularized fetal blood vessel scaffold after recellularization. In conclusion, our results have shown that an in vitro human vascular tissue slice experimental model using decellularized human fetal arteries is able to sustain an adequate scaffold for cellular implants.