Byung-Soon Park

Antiwrinkle effect of adipose-derived stem cell: Activation of dermal fibroblast by secretory factors

BACKGROUND Adipose-derived stem cells (ADSC) have wound-healing and antioxidant effects on human skin via secretion of growth factors and activation of dermal fibroblasts. OBJECTIVE Paracrine mechanism reducing ultraviolet-B (UVB)-induced wrinkles by ADSC is investigated in this study. METHODS AND RESULTS Wrinkles were induced by an eight-week UVB irradiation, and were significantly improved by the subcutaneous injection of ADSC in hairless mice. In a replica analysis, parameters involving wrinkles were improved with mid-level and high doses of ADSC (1x10(4) and 1x10(5) cells). Dermal thickness and collagen contents in the dermis also were increased in the ADSC-injected groups. To characterize the paracrine mechanism involving the antiwrinkle effect of ADSC, a conditioned medium of ADSC (ADSC-CM) was directly incubated in human dermal fibroblasts (HDF). UVB irradiation reduced the proliferation of HDF, but this was reversed by the pretreatment of ADSC-CM in a dose-dependent manner. In a cell cycle analysis, ADSC-CM decreased the UVB-induced apoptotic cell death, which was demonstrated by the reduced sub-G1 phase of HDF. In addition, the ADSC-CM increased the protein expression of collagen type I and decreased the protein level of matrix metalloproteinase 1 in HDF, which may account for the increased collagen contents in the dermis. CONCLUSIONS Collectively, these results indicate that the ADSC and its secretory factors are effective for UVB-induced wrinkles, and the antiwrinkle effect is mainly mediated by reducing UVB-induced apoptosis and stimulating collagen synthesis of HDF.

The wound-healing and antioxidant effects of adipose-derived stem cells

Background: The aim of tissue engineering is to repair and regenerate damaged organs using a combination of cells, biomaterials and growth factors. Mesenchymal stem cells within the stromal–vascular fraction of subcutaneous adipose tissue, that is adipose-derived stem cells (ADSCs) have been used in skin repair with satisfactory results. The production and secretion of growth factors has been reported to be an essential function of ADSCs, and diverse regenerative effects of ADSCs in the skin have been demonstrated. Objective: Recent research developments concerning the wound-healing and antioxidant effects of ADSCs are briefly described. Methods: Various experimental results regarding the wound-healing and antioxidant effect of ADSCs are introduced, and the mechanisms and identification of active proteins involved in these function are further discussed. Results/conclusion: Evidence of ADSC differentiation of skin has not been reported in vivo, but ADSCs accelerate wound-healing and exhibit antioxidant effects under various conditions. The wound-healing and antioxidant effects of ADSCs are mainly mediated by the activation of dermal fibroblasts and keratinocytes via the paracrine mechanism. Since ADSCs are easily obtained in large quantities and have an advantage over other stem cell sources, ADSCs and their secretory factors show promise for use in skin repair and regeneration.

Novel porous matrix of hyaluronic acid for the three-dimensional culture of chondrocytes

A novel three-dimensional (3D) scaffold of chemically unmodified hyaluronic acid (HA) with minimum cross-linkage was developed for the culture of chondrocytes, thereby to promote cartilage repair. The porous structure of the scaffold was observed by scanning electron microscopy (SEM), and the pore size was controlled by fabrication conditions including swelling time and composition of the HA matrix. Rabbit primary chondrocytes and human chondrocytic cell lines (C-20/A4) were cultured in the HA matrix to investigate whether they can be applied to construct the cartilage tissue in vitro. The chondrocytes retained chondrocytic spherical morphology in this HA matrix. Moreover, results from the MTT assay showed good cellular viability within the HA matrix; optical density increased for up to 28 days, demonstrating that the cells continued to proliferate inside the HA matrix. Phenotypic analysis (RT-PCR, Alcian blue staining and quantification of s-GAG) showed that chondrocytes, when three-dimensionally cultured within the HA matrix, expressed transcripts encoding collagen type II and aggrecan, and produced sulfated glycosaminoglycans (s-GAG), indicating chondrogenic differentiation. The new HA matrix therefore appears as a potentially promising scaffold for the three-dimensional culture of chondrocytes for cartilage tissue engineering.

Vitamin D receptor genotypes are not associated with clinical response to calcipotriol in Korean psoriasis patients

Abstract. Conflicting results have been reported on the association between BsmI restriction fragment length polymorphism (RFLP) at the vitamin D receptor gene (VDR) locus and the clinical response of psoriasis patients to calcitriol or calcipotriol therapy. We evaluated RFLPs of the VDR gene by analyzing the restriction pattern of polymerase chain reaction products in 55 Korean psoriasis patients receiving topical calcipotriol therapy, and evaluated the clinical response. Of the 55 patients, 43 completed the 8-week treatment protocol, and the response was evaluated as excellent in 9 patients, good in 20, and poor in 14. Thus, in our 43 patients BsmI and ApaI polymorphism in the VDR gene did not correlate with response to calcipotriol. The marked predominance of the b allele in the Korean population precludes the possibility that BsmI polymorphism is associated with clinical response to calcipotriol. The pattern of prevalence of the VDR genotypes in the Korean population is very different from that in Western populations. There were no differences in VDR genotype between controls and psoriasis patients at the BsmI site, but there were significant difference in terms of ApaI RFLP as previously reported. In conclusion, polymorphism analysis of the VDR gene with BsmI and ApaI restriction enzymes in psoriasis patients was not helpful in predicting clinical response to calcipotriol.

Characterization of Early and Late Onset Psoriasis in the Korean Population

It has been proposed that two types of psoriasis can be characterized based upon age of onset. The purpose of our study was to investigate the characteristics of early and late onset psoriasis in the Korean population. A total of 986 psoriasis patients were included in this study, and the age of onset frequency proved to be bimodal. Family history in the first‐degree relatives was significantly higher in the early onset group (<40 years old) when compared with the late onset group (≥40 years old). A series of statistical analyses concerning the correlation between the extent of involvement and age of onset showed that earlier onset is related to more extensive involvement. A questionnaire survey concerning the influence of various external factors upon their psoriasis was given to a subgroup of 800 psoriasis patients. Multiple logistic regression analysis, controlled for confounding factors such as current age, sex and extent of involvement, revealed that early onset psoriasis patients showed significantly increased tendencies to worsen at times of psychological stress and in winter, and to improve in summer, compared with late onset psoriasis patients. In conclusion, distribution of the age of onset revealed two peaks in Korean psoriasis patients, and psoriasis with an onset prior to the age of 40 years was associated with increased inheritability, greater susceptibility to seasonal changes and more psychological stress than psoriasis with later onset.

Effect of Quilting Sutures on Hematoma Formation after Liposuction with Dermal Curettage for Treatment of Axillary Hyperhidrosis: A Randomized Clinical Trial

BACKGROUND Liposuction provides further reduction of axillary sweating and malodor when combined with dermal curettage with sharp rasping cannulas. This aggressive approach is associated with relatively higher rate of hematoma formation when compared to the conventional simple liposuction. OBJECTIVE The aim of this prospective, randomized, controlled trial was to evaluate the effect of quilting sutures on the incidence of hematoma formation after liposuction-curettage for treatment of axillary hyperhidrosis (AH). MATERIALS AND METHODS The trial randomized 59 male patients (118 axillae) undergoing liposuction-curettage for AH to quilting procedures (61 axillae) or control group (57 axillae) for intention-to-treat analysis. Outcome measures included the incidence of hematoma formation, operative time, degree of postoperative pain, and amount of analgesics consumption. RESULTS Quilting sutures significantly reduced the incidence of axillary hematoma from 28.1% to 4.9%. Quilting was associated with the lengthening of operative time but did not affect the postoperative pain. CONCLUSION Considering its efficacy in reducing postoperative hematoma, quilting is recommended in combination with aggressive liposuction-curettage procedure for treating AH and osmidrosis.

Subcorneal pustular dermatosis in a patient with aplastic anemia

Subcorneal pustular dermatosis (SPD) is a chronic, relapsing vesiculopustular eruption that typically affects the trunk and intertriginous areas and usually occurs in women more than 40 years of age.1 We describe a case of SPD in a patient with aplastic anemia induced by antituberculosis medications. Although the association of SPD with paraproteinemia, myeloma, and inflammatory bowel diseases such as ulcerative colitis and Crohn’s disease has been recognized,2,3 an association with aplastic anemia has not been previously reported. CASE REPORT

Higher order kernels in adaptive location estimation

In the semiparametric location model, an adaptive location estimate can be obtained by plugging kernel estimates of density and its derivative into the one-step approximation of the parametric maximum likelihood estimate. In this paper, we investigate the effect of higher order kernels on second order asymptotics of the adaptive location estimate. The optimal order of bandwidths in terms of estimating the location parameter are established. We also give some simulation results to see the effect of higher order kernels for moderate sample sizes.

Variable bandwidth in nonparametric regression

In the context of estimating a probability density function use of a suitable variable bandwidth is known to improve the rate of convergence of the resulting kernel density estimator. In this paper we show that the same kind of improvement is possible in the regression setting. In particular we find that the fast rate of convergence derived by Hall (1990), using a bandwidth variation method that depends on the underlying regression function still holds when one uses an estimate of the regression function as a pilot.

On Bias reduction methods in nonparametric regression estimation

Standard nonparametric regression estimators such as Nadaraya-Watson, Priestly-Chao, Gasser-Muller, and local linear smoothing have convergence of order O(n -2/5) when the kernel weight functions used are of second order. We discuss here two recently proposed techniques which improve the convergence rate of any given nonparametric regression estimator. When they are applied to the basic O(n -2/5) methods, the convergence rate reduces to O(n -4/9). In this paper, we focus on the cases when these two methods are applied to the local linear smoothing. It is demonstrated by means of a Monte Carlo study that the asymptotic improvements are noticeable even for moderate sample sizes.