Advanced 3D model recreates hair follicle environment to better assess drug treatment

Hair follicles are convoluted structures that surround the hair root, anchoring it in the skin and providing the hair with grip. At the same time, the area between the skin and the hair follicle provides optimal conditions for the unlimited reproduction of microorganisms. This often leads to chronic inflammation of the hair follicle, which is not only painful, but in the case of acne inversa, can also cause secondary diseases such as diabetes or even acute sepsis. In Germany alone, around 830,000 people currently suffer from this disease.

In order to successfully develop recent dynamic substances against folliculitis, models are needed that can simulate the physiological conditions of the skin in the laboratory as realistically as possible. A team led by Prof. Claus-Michael Lehr from HIPS, the Helmholtz Centre for Infection Research (HZI) in collaboration with Saarland University, has developed just such a model. By transplanting living human hair follicles into a collagen matrix in a 3D-printed polymer scaffold, the researchers were able to successfully replicate the natural environment of hair follicles. “The model has the advantage that we can test recent drug candidates in the hair follicle microenvironment at an early stage of development, without having to resort to animal testing,” says Samy Aliyazdi, first author of the study.

Previously, recent drug candidates against hair follicle infections were initially tested in simpler models, such as free-floating human hair follicles in liquid culture. However, these models do not adequately represent real-life conditions in patients and are therefore not ideal for testing biological efficacy. Using the recent 3D model, the researchers have already shown that nanoparticles penetrate and distribute better in hair follicles than in free-floating hair follicle cultures. The nanoparticles are therefore able to penetrate deep into the hair follicles and are suitable as carriers of dynamic ingredients. Lehr’s team was also able to show that hair follicle infections with a hospital pathogen Staphylococcus aureus can be combated much more effectively if the antibiotic rifampicin is “packed” in such nanoparticles.

The 3D human hair follicle model described overcomes some of the challenges associated with previous lab models. “Our model provides a more realistic replication of the human hair follicle microenvironment and can be cultured for long periods of time. But we’re not there yet. We need to further optimize the mechanical properties of the polymer. We also plan to include additional cell types, such as fibroblasts and immune cells, to make the model even more representative of the patient situation,” says Aliyazdi. A more convoluted model of this type has the potential to provide valuable early insights into hair follicle viability, pathogen behavior, and ultimately predictive drug efficacy and safety assessment.

Our research shows that mimicking the natural environment of hair follicles is crucial for assessing the efficacy of antibiotics. This model could greatly accelerate the development of recent, targeted therapies while reducing the number of animal studies required.

Prof. Claus-Michael Lehr from HIPS