Novel sponge formulation of mesenchymal stem cell secretome and hyaluronic acid: a safe and effective topical therapy for Psoriasis vulgaris

Background: Psoriasis vulgaris is the most common form of psoriasis, yet current treatments often lead to significant side effects, resulting in a high rate of therapy desertion. Here, we explored a novel therapeutic approach using the secretome from Wharton Jelly-derived mesenchymal stem cells, biologically stabilized and enhanced with hyaluronic acid (HA), its presentation is an easy-to-apply topical sponge. This formulation had previously demonstrated efficacy in vitro and in experimental psoriasis mouse models. Methods: In vitro characterization studies included dynamic light scattering, nanoparticle tracking analysis, optical/electronic microscopy, microbiological experiments, and angiogenic capacity (HUVEC cells). In vivo studies included angiogenic capacity in chicken embryo chorioallantoic membrane (CAM), safety (hypersensitive and healthy volunteers), and efficacy (double-blinded and randomized patients). Results: We demonstrated the presence of spherical exosomes (164 ± 87 nm, PDI of 0.38, and 1.5 × 10⁷ particles/mL) within the selected secretomes, which exhibited significant proangiogenic activity in HUVEC cells and in a CAM assay. The secretome-containing sponges displayed distinct physicochemical properties, such as the absence of nitrogen and reduced carbon and oxygen content, resulting in a more cross-linked material with thinner fibers. These characteristics extended the dispersion time in aqueous media. Microbiological testing confirmed sterility in the packed, ready-to-use secretome-HA sponges after 3 months of storage. To assess safety, we selected doses (based on total protein content) that were applied to three patients with atopic dermatitis (42 µg of protein, patch test, 5 days) and four healthy volunteers (210 µg, 15 days) with no observed adverse topical or systemic effects. In a 30-day efficacy study, 12 patients with bilateral psoriasis exhibited up to a 33% reduction in mPASI scores and a 41% decrease in plaque size. Additionally, transepidermal water loss (TEWL) was reduced by up to 30%, while skin elasticity/flexibility improved by 43%. Conclusions: These findings suggest that the topical application of the secretome-HA sponge is a safe and effective therapeutic option for alleviating symptoms of psoriasis vulgaris. Trial registration: SSMN, SSMN047/2021. Registered 27 October 2021, https://www.ssmn.cl/comite_etica.php.