Relaxin (RLX) is a product of the theca interna layer of the developing pig follicle. However, its physiological role within the ovary is unknown. The purpose of this study was to determine the effects of RLX alone or in conjunction with insulin and insulin-like growth factor-I (IGF-I) on porcine granulosa cell (GC) DNA synthesis and proliferation in vitro. The results showed RLX (1-1000 ng/ml), insulin (1-1000 ng/ml), and IGF-I (1-30 ng/ml) alone stimulated [3H]thymidine incorporation into DNA by GC from small, medium, and large porcine follicles (P < 0.05). The effect of RLX in combination with insulin or with IGF-I on DNA synthesis by GC from small and medium follicles was greater than the effect of either single factor (P < 0.05). In the large follicle, RLX increased GC DNA synthesis synergistically with insulin and IGF-I. FSH (100 ng/ml) or estradiol (10(-7) M) had no effect on basal or RLX-induced [3H]thymidine incorporation into GC DNA at any stage of follicular development. After 6 days incubation in vitro, RLX dose-dependently increased proliferation of GC from small follicles (P < 0.05). The increased cell number in response to RLX correlates with RLX-induced [3H]thymidine incorporation into DNA by these GC. Hydroxyurea, an inhibitor of DNA synthesis, blocked RLX-induced thymidine incorporation, indicating that the increase in thymidine incorporation in response to RLX was due to DNA synthesis and not repair. This is the first demonstration that RLX acts as a growth factor in the porcine follicle by increasing GC DNA synthesis and proliferation in vitro. RLX enhanced the growth-promoting effects of insulin and IGF-I on GC, which suggests an interaction of RLX with these proteins during follicular growth. These studies support the concept that locally produced thecal RLX alone or in combination with other growth effectors may play a key role in GC growth during porcine follicular development.

Acne vulgaris is a disease of pilosebaceous units associated with increased follicular stratum corneum (SC) thickness and hyperkeratinization, increased sebum secretion, inflammation and impaired skin barrier. We hypothesized that excess unsaturated free fatty acids (UFFAs) in sebum may contribute to these symptoms seen in Acne. Therefore, skin surface lipids in acne and healthy subjects were investigated. In addition, a human epidermal equivalent (HEE) model treated topically with an UFFA was developed mimicking these symptoms seen in Acne. Gene expression profiling of human skin biopsies with and without acne lesions as well as of UFFA-treated HEEs Vs. controls was also performed. Increased levels of UFFAs were observed in skin lipids of human acne subjects. Topical treatment of HEEs with an UFFA resulted in impaired barrier and increased secretion of interleukin-1a (IL-1a), associated with SC thickening and hyperkeratinization, and with increased SC lipid conformational disorder indicating a decrease in barrier integrity. Furthermore, gene expression analysis showed a similar increase in gene expression of inflammatory cytokines and epidermal differentiation both in acne lesions and UFFA-treated HEEs. These data are in agreement with the hypothesis that excess unsaturated free fatty acids (UFFAs) in sebum may contribute to the increased follicular stratum corneum (SC) thickness and hyperkeratinization, inflammation and impaired skin barrier seen in Acne. Taken together, these results suggest that UFFA-treated epidermal tissue induces a phenotypic in vitro model of acne hyperkeratinization which can be useful for the investigation of treatments that modulate acne.

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Atmospheric dust comprises a myriad of both innocuous and harmful constituents. Airborne pollen, a notorious allergen, is one component of atmospheric dust. Different varieties of pollen allergens transport proteases on their surfaces that compromise epithelial barrier function by degrading tight junctions. In addition, pollen allergens induce reactive oxygen species, inflammatory response, and other allergic symptoms. The purpose of this study was to evaluate the physiological effects of pollen exposure on skin, specifically, evaluating changes in skin barrier function, inflammatory response, and collagen levels, as well to determine if treatment with antioxidants could mitigate any harmful effects. Human reconstructed skin models were exposed to aqueous extracts of the allergenic pollen Kentucky Bluegrass, after which changes in barrier function were assessed by measuring transepithelial electrical resistance (TEER) and transepidermal water loss (TEWL); pro-inflammatory cytokines were measured using ELISA assays for IL1a, IL6, and IL8; and collagen content was evaluated by measuring skin autofluorescence. Results showed that exposure of skin models to pollen extract resulted in (1) reduced barrier function of skin, as shown by significant reductions in TEER (p¼0.01) and increases in TEWL (p¼0.01), (2) reduction in skin collagen autofluorescence, and (3) increases in skin inflammatory response, indicated by a significant increase in IL6, IL1a, and Il8 levels (p¼0.01). Moreover, treatment of skins with antioxidants prevented the detrimental effects of pollen on skin barrier function, as shown by increases in TEER and reductions TEWL. We have shown here that exposure of skin to pollen induces impaired barrier function, a reduction in collagen, and increased inflammatory response, and that these harmful effects can be ameliorated by treatment with antioxidants.