Herein, three-dimensional (3D) bioprinting of engineered constructs with cell-laden biomaterials was investigated for the development of 3D tissue constructs in vitro. The present article proposes a simple coaxial-nozzle-based printing method using a one-step gelling gelatin bioink containing different cell types for vascular structure generation. First, a gelatin bioink prepolymer with a tyramine functional group was synthesized. To facilitate rapid gelation, polyethylene glycol (PEG) was introduced as a spacer between gelatin and tyramine. The gelatin–PEG–tyramine (GPT) prepolymer underwent enzymatic crosslinking, which yielded a higher gelation rate of up to 4.24 ± 0.08 s. Second, one-step bioprinting of a cell-laden tubular structure was demonstrated using a coaxial type extruder and the GPT bioink with human umbilical vein endothelial cells (HUVECs) with or without human dermal fibroblasts (HDFs). The printed no-cell GPT tube was demonstrated to possess a perfusable vascular structure. The extruded tube with HUVECs-in-GPT sheath configuration resulted in an endothelial cell-lined hollow structure and was maintained for up to 8 days in vitro. Additionally, the coaxially extruded tube with HUVECs-in-core (gelatin) and HDFs-in-GPT sheath (GPT) configuration exhibited a distribution of these two cell types along the tube axis. In the current study, it was demonstrated that a radial distribution of multiple vascular cells can be simply achieved using a synthetic GPT bioink combined with a coaxial nozzle printing system, serving as a proof-of-concept for one-step generation of vascular constructs. The rapid gelling bioink prepolymer, in combination with a coaxial bioprinter nozzle mechanism, has great potential for the development of designed, printed, and organized 3D tissue architecture vascularization.

The progression of androgenetic alopecia is closely related to androgen-inducible transforming growth factor (TGF)-β1 secretion by hair follicle dermal papilla cells (DPCs) in bald scalp. Physiological levels of androgen exposure were reported to increase reactive oxygen species (ROS) generation. In this study, rat vibrissae dermal papilla cells (DP-6) transfected with androgen receptor showed increased ROS production following androgen treatment. We confirmed that TGF-β1 secretion is increased by androgen treatment in DP-6, whereas androgeninducible TGF-β1 was significantly suppressed by the ROSscavenger, N-acetyl cysteine. Therefore, we suggest that induction of TGF-β1 by androgen is mediated by ROS in hair follicle DPCs. [BMB Reports 2013; 46(9): 460-464]

Ginseng has been shown to promote hair growth in several recent studies. However, its effects on human hair follicles and its mechanisms of action have not been sufficiently elucidated. This study aimed to investigate the hair growth-promoting effects of red ginseng extract (RGE) and its ginsenosides. The proliferative activities of cultured human hair follicles treated with RGE and ginsenoside-Rb1 were assessed using Ki-67 immunostaining. Their effects on isolated human dermal papilla cells (hDPCs) were evaluated using cytotoxicity assays, immunoblot analysis of signaling proteins, and the determination of associated growth factors. We examined the ability of RGE and ginsenosides to protect hair matrix keratinocyte proliferation against dihydrotestosterone (DHT)-induced suppression and their effects on the expression of androgen receptor. The in vivo hair growth-promoting effect of RGE was also investigated in C57BL/6 mice. Both RGE and ginsenoside-Rb1 enhanced the proliferation of hair matrix keratinocytes. hDPCs treated with RGE or ginsenoside-Rb1 exhibited substantial cell proliferation and the associated phosphorylation of ERK and AKT. Moreover, RGE, ginsenoside-Rb1, and ginsenoside-Rg3 abrogated the DHT-induced suppression of hair matrix keratinocyte proliferation and the DHT-induced upregulation of the mRNA expression of androgen receptor in hDPCs. Murine experiments revealed that the subcutaneous injection of 3% RGE resulted in more rapid hair growth than the negative control. In conclusion, RGE and its ginsenosides may enhance hDPC proliferation, activate ERK and AKT signaling pathways in hDPCs, upregulate hair matrix keratinocyte proliferation, and inhibit the DHT-induced androgen receptor transcription. These results suggest that red ginseng may promote hair growth in humans.

Background: Filler injection has become an extremely popular method for facial skin rejuvenation, including the periorbital area. In the recent years, new polynucleotide (PN)-containing filler products have been used for esthetic purposes. Aim: We aimed to investigate the efficacy and safety of PN filler injection in the periorbital area. Patients/methods: A total of 27 subjects were enrolled in this randomized, pair-matched, and active-controlled study. Each subject received filler injections thrice with two-week intervals, with a PN filler injection on one side and a non-crosslinked hyaluronic acid (HA) filler injection on the contralateral side of the periorbital area. Results: Improvements in the visual analog scale and global esthetic improvement scale scores were not significantly different between the PN and HA groups. The improvement rates of skin elasticity and hydration decreased over time in both groups, with the PN group showing a higher improvement rate. The improvement rates of roughness and pore volume were higher in the PN group than in the HA group. The improvement rate of dermal density was not significantly different between the groups. No serious adverse events were reported. Conclusion: The PN filler injection is effective and safe for periorbital rejuvenation.

Hidradenitis suppurativa (HS) is a chronic inflammatory disease, chiefly affecting apocrine gland–bearing skin.¹ Hidradenitis suppurativa is one of the most debilitating dermatologic conditions, and the association between HS and reductions in quality of life and psychosocial well-being has been widely reported.^2-5 Hidradenitis suppurativa is associated with severe comorbidities, which can lead to substantially reduced life expectancy.^6-10 While the pathogenesis of HS is unclear, several inflammatory cytokines, such as tumor necrosis factor (TNF), interferon-γ, interleukin (IL)-10, IL-12, IL-17, IL-23, and IL-32, as well as antimicrobial peptides LL-37, psoriasin, and β-defensins 2 and 3, may be factors in the development of the disease.^11-14 Specific genetic and environmental factors seem to contribute to the development and phenotype of HS.¹¹ The aberrant immune response and chronic inflammation in HS and genetic and environmental factors associated with the disease may all be factors in the development of cancer. The connection between HS and cancer has been suggested: a study of 2119 Swedish patients found that HS was associated with an approximate 50% increase in the relative risk of cancer.¹⁵ Cases of nonmelanoma skin cancer complicating HS have also been reported.^16,17 Vulvar, perianal, and perineal cancer can develop in patients with HS.¹⁸ An association between HS and lymphoma has also been reported recently.¹⁹ However, there are limited large, population-based epidemiologic studies regarding the risks of overall and specific cancers among patients with HS. Thus, we conducted a nationwide, population-based study to determine the overall and specific cancer risks in patients with HS compared with the risks in patients without HS in the Republic of Korea.