Opt-out defaults do not increase organ donation rates.

OBJECTIVES: To increase organ donation rates, many countries have switched from an opt-in ('explicit consent') default for organ donation to an opt-out ('presumed consent') default. This study sought to determine the extent to which this change in default has led to an increase in the number of deceased individuals who become organ donors. STUDY DESIGN: Longitudinal retrospective analysis. METHODS: We conducted a retrospective analysis of within-country longitudinal data to assess the effect of changing the organ donation default policy from opt-in to opt-out. Our analysis focused on the longitudinal deceased donor rates in five countries (Argentina, Chile, Sweden, Uruguay, Wales) that had adopted this change. Using a Bayesian aggregated binomial regression model, we estimated the odds of organ donation within each country over time, as well as the effect of the policy switch. RESULTS: Switching from an opt-in to an opt-out default did not result in an increase in donation rates when averaged across countries. Moreover, the opt-out default did not lead to even a gradual increase in donations: there was no discernible difference in the linear rate of change of donations after the change in default. Finally, the COVID-19 pandemic was associated with a reduction in the odds of donation across all five countries. CONCLUSIONS: Our longitudinal analysis suggests that changing to an opt-out default does not increase organ donation rates. Unless flanked by investments in healthcare, public awareness campaigns, and efforts to address the concerns of the deceased's relatives, a shift to an opt-out default is unlikely to increase organ donations.

Systemic immunosuppression by methylprednisolone and pregnancy rates in goats undergoing the transfer of cloned embryos.

The presence of the zona pellucida has been perceived as a requirement for the oviductal transfer of cloned embryos at early stages of development while protecting the embryo from an immune system response. We hypothesized that steroid hormone therapy could reduce a potential cellular immune response after the transfer of zona-free cloned embryos into the oviduct of recipient female goats. In Experiment 1, seven does were used to study the systemic immunosuppressant effect of the methylprednisolone administration (for 3 days) on blood cell counts. Whole blood was collected prior to treatment with methyprednisolone and then on Days 1, 2, 3, 4, 7, 14, 21 and 28 after the first dose of methylprednisolone for the analysis of haematological parameters. Methylprednisolone treatment significantly reduced circulating white blood cells and neutrophils in comparison with pre-treatment levels, demonstrating a systemic immunosuppressant effect. In Experiment 2, a group of 58 does were used as recipient females to study the effect of administration of methylprednisolone for 3 days on the establishment of pregnancies after the transfer of zona-free cloned embryos into the oviducts. No effects on pregnancy rates on Day 30 were observed regarding the distinct treatment groups (control vs. methylprednisolone), the source of oocytes (in vivo- vs in vitro-matured) or the presence or absence of the zona pellucida in embryos. In summary, methylprednisolone was effective at inducing a systemic immunosuppressed state in goats, but the treatment prior to embryo transfer did not affect pregnancy rates. Moreover, pregnancy rates were similar between zona-free and zona-intact goat cloned embryos.