The role of donor hypertension and angiotensin II in the occurrence of early pancreas allograft thrombosis.

Background: About 10-20% of pancreas allografts are still lost in the early postoperative period despite the identification of numerous detrimental risk factors that correlate with graft thrombosis. Methods: We conducted a multicenter study including 899 pancreas transplant recipients between 2000 and 2018. Early pancreas failure due to complete thrombosis, long-term pancreas, kidney and patient survivals were analyzed and adjusted to donor, recipient and perioperative variables using a multivariate cause-specific Cox model stratified to transplant centers. Results: Pancreas from donors with history of hypertension (6.7%), as well as with high body mass index (BMI), were independently associated with an increased risk of pancreas failure within the first 30 post-operative days (respectively, HR= 2.57, 95% CI from 1.35 to 4.89 and HR= 1.11, 95% CI from 1.04 to 1.19). Interaction term between hypertension and BMI was negative. Donor hypertension also impacted long-term pancreas survival (HR= 1.88, 95% CI from 1.13 to 3.12). However, when pancreas survival was calculated after the postoperative day 30, donor hypertension was no longer a significant risk factor (HR= 1.22, 95% CI from 0.47 to 3.15). A lower pancreas survival was observed in patients receiving a pancreas from a hypertensive donor without RAAS (Renin Angiotensin Aldosterone System) blockers compared to others (50% vs 14%, p < 0.001). Pancreas survival was similar among non-hypertensive donors and hypertensive ones under RAAS blockers. Conclusion: Donor hypertension was a significant and independent risk factor of pancreas failure. The well-known pathogenic role of renin-angiotensin-aldosterone system seems to be involved in the genesis of this immediate graft failure.

Atualização em xenotransplante / An update on xenotransplantation

Ainda existem muitos obstáculos a vencer até que o xenoenxerto seja uma realidade na prática clínica dos transplantes. O transplante discordante é o que tem maior chance de viabilização, sendo o porco o animal mais estudado. A principal barreira imunológica ao xenotransplante é a rejeição hiperaguda. Inúmeras técnicas começam a estar disponíveis com o propósito de ultrapassar essa difícil etapa. Métodos de transgênese e de indução de tolerância são promissores na tentativa de controlar o processo. Ao mesmo tempo em que progridem os estudos sobre o controle imunológico do xenotransplante, iniciam- se outros visando avaliar o risco real de disseminação de retrovírus aos humanos, assim como os de avaliação fisiológica de enxerto de porco. Também existem discussões éticas pertinentes ao uso de animais como doadores de órgãos(au)