LIALT's VITROFEM: Alternative Vaginal Irritation Test

Intimate hygiene products have traditionally been evaluated using methods that have both ethical and scientific limitations. In this context, VITROFEM has emerged as a model in vitro model of human vaginal tissue developed by LIALT, which makes it possible to evaluate the safety and efficacy of these products without resorting to the use of animals.

What are intimate hygiene products?

Intimate hygiene products are items designed for the care and hygiene of the genital area. They include cleansing gels, wet wipes, foams, lotions, creams, lubricants, panty liners, and tampons, among others. They are formulated to maintain pH balance, prevent infections, and provide a feeling of freshness, although not all are necessary or recommended, according to gynecologists.

Since these products are designed for a sensitive area, their development requires high safety standards. However, before reaching the market, many have been evaluated through in vivo testing—that is, on animals.

Among these tests is the vaginal irritation test, which involves the repeated application of substances inside the vaginas of animals, such as rabbits, to observe possible effects such as inflammation, irritation, or infection. The animals are then euthanized for histological analysis.

These practices have been the subject of both ethical and scientific criticism due to the physiological differences between the vaginal anatomy of rabbits and that of humans. Furthermore, many of the products tested are not intended for use in these animals—such as lubricants, spermicides, or sanitary pads—which limits the validity of the results. Added to this are differences in reproductive cycles between species, both in duration and in biological responses.

Furthermore, there is a historical gap in research on vaginal and uterine health, which has contributed to the use of models that are not very representative and, in some cases, are based on outdated information. These limitations can result in assessments that do not adequately reflect the effects on people, reinforcing the need to move toward more accurate methods.

In this context, in vitro models that replicate human vaginal tissue have emerged, offering more ethical alternatives with greater scientific relevance for evaluating the safety of intimate hygiene products. Among these advances, the work of the Alternative Research Laboratory (LIALT) stands out; the lab developed VITROFEM as an innovative solution in this field.

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What is VITROFEM, and what does it offer?

VITROFEM is an in vitro model that recreates human vaginal tissue in three dimensions without the use of animals. This system allows for the ethical evaluation of the irritation, toxicity, and safety of intimate hygiene products with greater scientific relevance, reducing the risks associated with extrapolating results obtained from other species.

The model uses human vaginal epithelial cells and fibroblasts to reconstruct a three-dimensional tissue that more accurately mimics the actual biological environment. Through these techniques, it establishes itself as a safe, reproducible alternative that is aligned with the development of animal-free methods for vaginal irritation testing.

How does VITROFEM work?

The model uses primary human epithelial cells obtained from ethically approved samples. These cells play a key role as a protective barrier, lining organs and cavities, and allow for the study of processes such as inflammation, tissue regeneration, and defense mechanisms. Under culture conditions, they have the ability to stratify and form a multilaminar epithelium, which makes it easier to more accurately replicate the vaginal microenvironment.

To increase the model’s complexity and representativeness, human fibroblasts—cells that play a key role in the synthesis of collagen and other components of the extracellular matrix—are incorporated. Their presence makes it possible to recreate a functional stroma that delivers biochemical and mechanical signals, directly influencing the differentiation and balance of the epithelium.

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To verify that the model accurately reproduces human vaginal epithelium, an immunocytochemical assay is performed using specific markers of epithelial differentiation. This process utilizes cytokeratins such as CK14 and CK18, proteins that allow for the identification of different types of epithelial cells. CK14 is present in the basal cells of the deepest layer of the vaginal epithelium, which are responsible for tissue regeneration.

In contrast, CK18 is associated with simple epithelia, such as those of the intestine or liver, and should not be expressed in the vaginal epithelium. In VITROFEM, the cells express CK14 but not CK18, indicating proper differentiation and an accurate representation of human vaginal tissue.

This analysis supports the validity of the model as an experimental tool, allowing for the noninvasive evaluation of gynecological products, probiotics, topical medications, and microbiological studies, in line with the 3Rs principle.

By analyzing cellular viability and potential responses such as inflammation or tissue damage, VITROFEM makes it possible to replace animal testing, promoting more ethical methods with greater scientific relevance. As a result, it stands as an effective alternative for evaluating the safety and efficacy of intimate hygiene products without resorting to the use of animals.

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The development of models such as VITROFEM demonstrates how scientific innovation can go hand in hand with ethical criteria in the evaluation of everyday products. Choosing products from brands committed to these standards also helps foster a more responsible industry.