Ex Vivo Culture Models of Hidradenitis Suppurativa for defining molecular pathogenesis and treatment efficacy of novel drugs

Hidradenitis suppurativa (HS) is a complex inflammatory and debilitating skin disease for which no effective treatment is available. This is partly because of the unavailability of suitable human or animal models with which exact pathobiology of the disease can be defined. Here, we describe the development of air-liquid (A-L) interface, liquid-liquid/liquid-submersion (L-S) and bioreactor (Bio) ex vivo skin culture models. All three ex vivo platforms were effective for culturing skin samples up to day-14, with the tissue architecture and integrity remaining intact for at least 3 days for healthy skin while for 14 days for HS skin. Up to day-3, no significant differences were observed in % early apoptotic cells among all three platforms. However, an increase was observed in late apoptotic/necrotic cells in HS skin at day-3 in A-L and Bio culture of HS skin. These cultures efficiently support the growth of various cells populations, including keratinocytes and immune cells. Profiling of the inflammatory genes using HS skin from these ex vivo cultures showed dynamic expression changes at day-3 and day-14. All of these cultures are necessary to represent the inflammatory gene status of HS skin at day-0 suggesting that not all gene clusters are identically altered in each culture method. Similarly, cytokine/chemokine profiling of the supernatant from vehicle- and drug-treated ex vivo HS cultures again showed better prediction of drug efficacy against HS. Overall, development of these three systems collectively provide a powerful tool to uncover the pathobiology of HS progression and screen various drugs against HS.