Spotlight on Three Rs Progress

Replacing Animal Research Changemaker Award winners

Replacing Animal Research has recently announced the two winners of their new Changemaker Award. The Award was launched to celebrate the people making a real, tangible impact in science. From building regional hubs for new technologies to tackling systemic bias in publishing, these winners are changing the landscape for good. Each winner received £500 to support their vital work in advancing animal-free research. We send our congratulations to:

— Professor Marize Campos Valadares, Professor of Toxicology at Federal University of Goiás in Brazil. Marize has spent two decades integrating non-animal methods into regulatory frameworks and education; and

— Catharine E. Krebs, Program Manager at the Physicians Committee for Responsible Medicine. Catharine founded the Coalition to Address and Illuminate Animal Methods Bias (COLAAB) to tackle the systemic preference for animal-based research in peer-review and funding.

The UK Animals in Science Committee new member from Replacing Animal Research

The Animals in Science Committee (ASC) is an independent UK advisory non-departmental public body that provides expert advice to the Home Office and Northern Ireland Department of Health on the use of animals in scientific procedures. It was established in 2013, when the updated Animals (Scientific Procedures) Act 1986 required the creation of a Committee for the Protection of Animals used for Scientific Purposes. It focuses on animal welfare, ethical review, and promoting replacement, reduction and refinement, providing independent, impartial advice to the Secretary of State and Animal Welfare and Ethical Review Bodies (AWERBs) on sharing best practice.

Dr Juliet P. Dukes, Research Manager at Replacing Animal Research, has been appointed (with five other new members) to the ASC for three years, following a robust process conducted in accordance with the Governance Code on Public Appointments.¹ Juliet said: “Although I represent myself, rather than Replacing Animal Research, while serving on the ASC, I am really looking forward to being able to bring all my knowledge, skills and experience from my work to this role. I can’t deny that the responsibility is a daunting prospect for me, but I’m grabbing this opportunity with all four paws and I will do my utmost for both animals and science.”

3Rs Hall of Honor

The 3Rs Hall of Honor was established in April 2024, by the Johns Hopkins Center for Alternatives to Animal Testing and ALTEX, “…to honor, recognize, and celebrate significant lifetime achievements in the pursuit of animal research and testing reduction, refinement, and replacement — principles collectively known as the 3Rs — by distinguished leaders in the field”.¹ The inaugural inductees were William M.S. Russell (1925–2006), Rex L. Burch (1926–1996), Franz P. Gruber (1942–2023) and Martin Stephens (1956–2024). Individuals, deceased or alive, from various sectors (including academia, industry, government and NGOs), who have significantly advanced the Three Rs in areas such as scientific research and testing, or policy, are eligible for nomination. The 2026 inductees are:

— Herman Koëter (d. 2025)

— Manfred Liebsch (1947–2025)

— Walter Pfaller (1945–2025)

— Gilman D. Veith (1944–2013)

— Michael Balls

— Alan Goldberg

— Claus-Michael Lehr

— Andrew Rowan

— Horst Spielmann

The award ceremony was held on 26 May 2026 as a hybrid event, with the in-person event taking place at the Hopkins Bloomberg Center, Washington, DC, USA.

Development of a cervix-on-a-chip model

The human cervicovaginal mucosa has been challenging to reproduce in vitro and animal models are not physiologically relevant for the study of genital pathogens. To address this gap and develop a low-cost, transferable microphysiological system (MPS) that permits the study of host microbiota–pathogen interactions, Nelson et al.¹ engaged a multidisciplinary team of biomedical engineers and microbiome researchers. The team came up with a modular MPS device that incorporates a single-use removable insert for cell culture and a reusable cassette. Importantly, it can be prepared without the need for cleanroom facilities. This configuration fits into a standard tissue culture incubator, permits static and flow conditions, and is compatible with standard downstream biological assays.

The team then validated the MPS device by successfully coculturing cervical epithelial cells with defined ‘optimal’ and ‘non-optimal’ vaginal microbiota species within the insert, and tested the host cells’ susceptibility to infection by two important genital pathogens (Chlamydia trachomatis and Neisseria gonorrhoeae). The MPS device was shown to reproduce the cervical microenvironment, support complete infection cycles of the two pathogens, and display characteristic host defence mechanisms under different conditions (e.g. ‘optimal’ and ‘non-optimal’ microbiome). It represents an important advance over existing in vitro models, representing a physiologically relevant and easily transferable tool for studying female genital infections.

The senior author of the paper, Prof. Jacques Ravel, told ATLA: “One of the major goals of this work was to reduce reliance on animal models by creating a human cervical model that better reflects human biology and its microbiome. The work will also increase scientific robustness because the human cervicovaginal environment is markedly distinct from that of rodents, particularly in its microbiota and immune responses. As such, many important aspects of sexually transmitted infections cannot be faithfully modelled in animals, or in simple cell culture systems that do not harbour the critically important microbiome. Equally important, we designed the system to be low-cost, reproducible, and usable by laboratories without specialised engineering infrastructure. We believe that making these advanced models broadly accessible is essential for improving reproducibility and accelerating innovation in translational reproductive health research, without relying on animal models.”

Improved human skin explant culture

Human skin explants are used for research into wound healing, including to investigate drug delivery and the efficacy of topical treatments. However, animal-derived components, which can potentially affect cell and tissue responses, are still commonly included in the tissue culture protocols. In an attempt to improve the physiological relevance of this model for preclinical drug testing, Guo et al. sought to test the effects of non-animal derived media and supplements on the wound healing process of skin explants.¹ The team cultured explants with superficial wounds in three distinct medium formulations (DMEM, CnT-Prime™ and EpiLife™) with a combination of various supplements (fetal calf serum, normal human serum and a plant-derived oxygen carrier protein). They compared specific wound healing markers with those of explants cultured in conventional fetal calf serum-supplemented DMEM. It was evident that the culture conditions affected re-epithelialisation, angiogenesis, extracellular matrix deposition and tissue remodelling — all of which are key events in the wound healing process. The results showed that, for the purposes of testing wound healing agents on human skin explants, the use of normal human serum in combination with the oxygen carrier was comparable to FCS supplementation. Interestingly, the authors remarked that, while skin explant models do not accurately mimic the healing process of acute wounds (e.g. absence of immune/hormonal signalling and vascularisation, and loss of metabolic activity), they can be useful to represent chronic wounds (e.g. leg ulcers), as these are characterised by limited blood flow.

In vitro embryo implantation study

Embryo implantation into the superficial layers of the endometrium marks the start of pregnancy. It is a crucial stage in the gestational process, as the connections established between the embryo and the uterus are necessary for long-term gestation. However, it suffers from a high failure-rate, and there is currently a limited understanding of the processes involved. Studies are challenging, for obvious practical and ethical considerations, and they are also hindered by the lack of suitable model systems.

To address these limitations, Molè et al.¹ described the establishment of an in vitro model that recapitulates the luminal, glandular and stromal compartments of the superficial layer of receptive human endometrium. Their model, which is based on endometrial biopsy-derived primary cells, was shown to exhibit important morphological and functional features, such as hormone-induced decidualisation of stromal cells, development of a luminal epithelium, and glandular invaginations that secrete histotrophic proteins to support embryo growth. Implantation studies confirmed that both human embryos and stem cell-derived blastoids were able to implant into the endometrial model and develop into advanced trophoblast structures. Furthermore, gene expression analysis of the early embryo–endometrial interface revealed particular ligand–receptor interactions within the embryo implantation niche, suggesting potential competition or mutual regulation between the growing embryo and the surrounding endometrial tissues. The authors noted that: “This model overcomes a long-standing barrier by enabling direct study of human embryogenesis and early placentation.”¹ Understanding the cellular and molecular mechanisms involved in this particular phase of gestation is essential for characterising the chain of events leading to a healthy pregnancy.