Development of ex situ normothermic reperfusion as an innovative method to assess pancreases after preservation

International audienceStatic cold storage (SCS) is the standard method for pancreas preservation prior to transplantation; however, it does not permit organ assessment. Normothermic reperfusion (NR) is utilized clinically for other organs to assess viability. Our aim was to develop NR using normothermic machine perfusion technique to simulate reperfusion at the time of transplantation, enabling evaluation of oxygenated hypothermic machine perfusion (HMPO2) as a newer strategy to optimize pancreas preservation. 13 porcine pancreases procured after circulatory death were divided into 3 groups: 4 pancreases preserved using SCS, and 2 groups preserved by HMPO2 (n = 4 and n = 5, differing by type of preservation solution). Duration of perfusion or cold storage was 6 hours before the 1-hour assessment using NR. Outcome measures were perfusion characteristics, biochemistry and change in tissue water mass as oedema assessment. During NR, the HMPO2 groups demonstrated better perfusion characteristics, normal macroscopic appearances, decreased water mass and one HMPO2 group demonstrated a response to glucose stimulation. Conversely, the SCS group showed an increased water mass and developed early macroscopic appearances of oedema, interstitial haemorrhage and minimal portal outflow. This study suggests that ex situ assessment of pancreases by NR is promising, and that HMPO2 may be better than SCS

SARS-CoV-2-Specific T Cell Responses Are Not Associated with Protection against Reinfection in Hemodialysis Patients.

Patients on hemodialysis (HD) are vulnerable to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and mount poor neutralizing antibody responses after two-dose vaccination. Although serological responses have been associated with reduced rates of reinfection, the relationship between cellular immunogenicity and protection has not been established. We report, for the first time, high incidence of reinfection in patients on HD who are vaccine naive (25%), which identifies that T cell responses do not predict protection against reinfection. Instead, patients on HD who went on to become reinfected had mounted highly variable and sometimes robust proliferative T cell responses to a broad array of SARS-CoV-2 peptide pools during the primary infection. The understanding that SARS-CoV-2–specific T cell responses are not predictive of protection against future infection will be a critical issue when measuring clinical efficacy of vaccination in these vulnerable cohorts, particularly when facing rapidly emerging variants of concern