Can remote endarterectomy expand access to kidney transplantation in patients with severe iliac calcification?

Severe iliac artery calcification in patients with end-stage renal disease is a common barrier to listing for kidney transplant. While few surgical solutions to iliac calcification have been reported, improving treatment may thus improve access to transplant care. Here we present two cases of a novel application of remote endarterectomy of the external iliac artery to facilitate listing for renal transplant. Both patients were listed following remote endarterectomy, followed by successful renal transplants using the treated vessels.

Xenotransplantation: A New Era.

Organ allotransplantation has now reached an impassable ceiling inherent to the limited supply of human donor organs. In the United States, there are currently over 100,000 individuals on the national transplant waiting list awaiting a kidney, heart, and/or liver transplant. This is in contrast with only a fraction of them receiving a living or deceased donor allograft. Given the morbidity, mortality, costs, or absence of supportive treatments, xenotransplant has the potential to address the critical shortage in organ grafts. Last decade research efforts focused on creation of donor organs from pigs with various genes edited out using CRISPR technologies and utilizing non-human primates for trial. Three groups in the United States have recently moved forward with trials in human subjects and obtained initial successful results with pig-to-human heart and kidney xenotransplantation. This review serves as a brief discussion of the recent progress in xenotransplantation research, particularly as it concerns utilization of porcine heart, renal, and liver xenografts in clinical practice.

Humoral immunity against SARS-CoV-2 variants including omicron in solid organ transplant recipients after three doses of a COVID-19 mRNA vaccine.

Objectives: Solid organ transplant recipients (SOTR) receiving post-transplant immunosuppression show increased COVID-19-related mortality. It is unclear whether an additional dose of COVID-19 vaccines can overcome the reduced immune responsiveness against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants. Methods: We analysed humoral immune responses against SARS-CoV-2 and its variants in 53 SOTR receiving SARS-CoV-2 vaccination. Results: Following the initial vaccination series, 60.3% of SOTR showed no measurable neutralisation and only 18.9% demonstrated neutralising activity of > 90%. More intensive immunosuppression, antimetabolites in particular, negatively impacted antiviral immunity. While absolute IgG levels were lower in SOTR than controls, antibody titres against microbial recall antigens were higher. By contrast, SOTR showed reduced vaccine-induced IgG/IgA antibody titres against SARS-CoV-2 and its delta variants and fewer linear B-cell epitopes, indicating reduced B-cell diversity. Importantly, a third vaccine dose led to an increase in anti-SARS-CoV-2 antibody titres and neutralising activity across alpha, beta and delta variants and to the induction of anti-SARS-CoV-2 CD4+ T cells in a subgroup of patients analysed. By contrast, we observed significantly lower antibody titres after the third dose with the omicron variant compared to the ancestral SARS-CoV-2 and the improvement in neutralising activity was much less pronounced than for all the other variants. Conclusion: Only a small subgroup of solid organ transplant recipients is able to generate functional antibodies after an initial vaccine series; however, an additional vaccine dose resulted in dramatically improved antibody responses against all SARS-CoV-2 variants except omicron where antibody responses and neutralising activity remained suboptimal.