Extracorporeal life support without systemic anticoagulation: a nitric oxide-based non-thrombogenic circuit for the artificial placenta in an ovine model

The biological role and future therapeutic uses of nitric oxide in extracorporeal membrane oxygenation, a narrative review

BACKGROUND

Nitric oxide (NO) is a gas naturally produced by the human body that plays an important physiological role. Specifically, it binds guanylyl cyclase to induce smooth muscle relaxation. NO's other protective functions have been well documented, particularly its protective endothelial functions, effects on decreasing pulmonary vascular resistance, antiplatelet, and anticoagulation properties. The use of nitric oxide donors as vasodilators has been known since 1876. Inhaled nitric oxide has been used as a pulmonary vasodilator and to improve ventilation perfusion matching since the 1990s. It is currently approved by the United States Food and Drug Administration for neonates with hypoxic respiratory failure, however, it is used off-label for acute respiratory distress syndrome, acute bronchiolitis, and COVID-19.

PURPOSE

In this article we review the currently understood biological action and therapeutic uses of NO through nitric oxide donors such as inhaled nitric oxide. We will then explore recent studies describing use of NO in cardiopulmonary bypass and extracorporeal membrane oxygenation and speculate on NO's future uses.

Ethical challenges in first-in-human trials of the artificial placenta and artificial womb: not all technologies are created equally, ethically

Artificial placenta and artificial womb technologies to support extremely premature neonates are advancing toward clinical testing in humans. Currently, no recommendations exist comparing these approaches to guide study design and optimal enrollment eligibility adhering to principles of research ethics. In this paper, we will explore how scientific differences between the artificial placenta and artificial womb approaches create unique ethical challenges to designing first-in-human trials of safety and provide recommendations to guide ethical study design for initial human translation.

The artificial placenta and EXTEND technologies: one of these things is not like the other

The so called "Artificial Placenta" and "Artificial Womb" (EXTEND) technologies share a common goal of improving outcomes for extreme premature infants. Beyond that goal, they are very dissimilar and, in our view, differ sufficiently in their technology, intervention strategy, demonstrated physiology, and risk profiles that bundling them together for consideration of the ethical challenges in designing first in human trials is misguided. In this response to the commentary by Kukora and colleagues, we will provide our perspective on these differences, and how they impact ethical clinical study design for first-in-human trials of safety/feasibility, and subsequently efficacy of the two technologies.

The new frontier in ECLS: Artificial placenta and artificial womb for premature infants

Outcomes for extremely low gestational age newborns (ELGANs), defined as <28 weeks estimated gestational age (EGA), remain disproportionately poor. A radical paradigm shift in the treatment of prematurity is to recreate the fetal environment with extracorporeal support and provide an environment for organ maturation using an extracorporeal VV-ECLS artificial placenta (AP) or an AV-ECLS artificial womb (AW). In this article, we will review clinical indications, current approaches in development, ongoing challenges, remaining milestones and ethical considerations prior to clinical translation.