Enhanced Anti-inflammatory Effects of γ-irradiated Pig Placenta Extracts

Targeting estrogen signaling and biosynthesis for aged skin repair

Non-healing skin wounds are disproportionally prevalent in older adults. Current treatments do not account for the particularities of aged skin and result in inadequate outcomes. Overall, healing chronic wounds in the elderly remains a major unmet clinical need. Estrogens play a critical role in reproduction but also have important actions in non-reproductive organs. Estrogen biosynthesis and signaling pathways are locally activated during physiological wound healing, processes that are inhibited in elderly estrogen-deprived skin. Estrogen deprivation has been shown to be a critical mediator of impaired wound healing in both postmenopausal women and aged men, and topical estrogen application reverses age-associated delayed wound healing in both elderly men and women. These data indicate that adequate estrogen biosynthesis and properly regulated estrogen signaling pathways are essential for normal wound healing and can be targeted to optimize tissue repair in the elderly. However, due to fundamental questions regarding how to safely restore estrogen signaling locally in skin wounds, there are currently no therapeutic strategies addressing estrogen deficiency in elderly chronic wounds. This review discusses established and recent literature in this area and proposes the hypothesis that estrogen plays a pleiotropic role in skin aging and that targeting estrogen signaling and biosynthesis could promote skin repair in older adults.

Topical anti-inflammatory and anti-oxidative effects of porcine placenta extracts on 2,4-dinitrochlorobenzene-induced contact dermatitis

Background

The placenta is a reservoir enriched with growth factors, hormones, cytokines and minerals. While several beneficial effects of placenta extracts on wound healing, anti-aging and anti-inflammatory responses have been reported, relatively limited mechanistic exploration has been conducted to date. Here, we provide compelling evidence of anti-inflammatory and anti-oxidative activities of porcine placenta extracts (PPE) against contact dermatitis in vivo.

Methods

A contact dermatitis mouse model was established by sensitizing the dorsal skin of BALB/c mice using the contact allergen, 2,4-dinitrochlorobenzene (DNCB), and molecular consequences of topical application of PPE were investigated. PPEs were pre-sterilized via γ-irradiation, which is a milder but more effective way of sterilizing biomolecules relative to the conventional autoclaving method.

Results

DNCB-induced skin lesions displayed clear contact dermatitis-like symptoms and topical application of PPE dramatically alleviated both local and systemic inflammatory responses. Inflammatory epidermal thickening was completely abrogated and allergen-specific serum IgE levels significantly reduced in the presence of PPE. Moreover, anti-oxidative activities of PPE were observed both in vitro and in vivo, which may lead to attenuation of inflammatory responses. Prolonged treatment with PPE strongly inhibited production of DNCB-induced reactive oxygen species (ROS) and subsequently prevented oxidative degradation of hyaluronic acid (HA), which triggers innate inflammatory responses.

Conclusion

Our findings supply valuable insights into the mechanisms underlying the anti-inflammatory effects of PPE and provide a functional basis for the clinical application of PPE in inflammatory diseases.

Electronic supplementary material

The online version of this article (10.1186/s12906-018-2396-1) contains supplementary material, which is available to authorized users.

Anti-inflammatory Effect of the Water-Soluble Portion of Porcine Placental Extract in Lipopolysaccharide-Stimulated RAW264.7 Murine Macrophage Cells

Porcine placental extract (PPE) is used as a nonprescription drug for analeptics and in health foods and cosmetics in Japan, Korea and China. It was reported that PPE has anti-oxidative and anti-inflammatory activities; however, the mechanisms and the responsible molecules involved in these activities are still unclear. Here, we investigated how enzymatically prepared PPE affects proinflammatory factors such as interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α in a cultured macrophage cell line, RAW264.7, when co-stimulated with lipopolysaccharide (LPS). Enhanced production of IL-1β, IL-6 and TNF-α by LPS was significantly reduced by the addition of PPE and these effects were dose dependent. Nitric oxide (NO) production induced in cultured macrophages by LPS was also inhibited by PPE. Real-time PCR after the reverse transcription of total RNAs isolated from cells treated with PPE revealed that the mRNA expressions of IL-1β, IL-6, TNFα, and NO synthase (NOS)-2 were reduced. The necessary concentration of PPE prepared by enzymatic digestion to mediate anti-inflammatory effects compared with the reported value of that extracted by phosphate buffered saline without digestion was proportional to the amount of extracted materials from the same amount of placenta (about 10-fold). This suggests that the molecules responsible for the anti-inflammatory activity exists in the placenta and can be extracted by phosphate buffered saline, and thus might survive enzymatic digestion.