Yun-Suk Lee

The roles of Wnt antagonists Dkk1 and sFRP4 during adipogenesis of human adipose tissue‐derived mesenchymal stem cells

Abstract.  Objectives: The canonical Wnt signalling pathway performs an important function in the control of adipogenesis. However, the mechanisms and mediators underlying these interactions have yet to be defined in detail. Thus, this study was performed in order to elucidate the roles of the Wnt family during adipogenic differentiation of human adipose tissue‐derived mesenchymal stem cells (hAMSCs). Materials and methods: We assessed several members of the Frizzled (FZD) family, the receptors of Wnts, inhibitors including the secreted frizzled‐related protein (sFRP) family and Dickkopfs (Dkks), and the downstream factor, β‐catenin. Expressional levels of adipogenic markers regulated by the small interfering RNA of Dkk1 (siDkk1) and sFRP4 (sisFRP4) were assessed using real‐time quantitative PCR and Western blot analysis. Results: The mRNA level of Dkk1 was expressed abundantly in the early stages of adipogenesis and decreased rapidly during the late stages of adipogenesis. However, sFRP4 mRNA was up‐regulated gradually during adipogenic differentiation in hAMSCs. Expression of FZD1, FZD7 and β‐catenin were reduced during adipogenic differentiation. Transfection of hAMSCs with siDkk1 or sisFRP4 partially inhibited differentiation of hAMSCs into adipocytes and restored levels of β‐catenin. Conclusions: We determined that Dkk1 was up‐regulated transiently in the early stages of adipogenesis, and that sFRP4 levels increased gradually during adipogeneis via inhibition of Wnt signalling. Collectively, these results show that Dkk1 and sFRP4 perform an important function in adipogenesis in hAMSCs.

Living arrangements and suicidal ideation among the Korean older adults

Objectives: This study examines how living arrangements are associated with suicidal ideation for older adults in South Korea, which has the highest suicide rate among OECD countries, and a particularly high suicide rate for older persons. Methods: Analyzing a sample of 5795 women and 3758 men aged 65 and older from a nationwide representative cross-sectional data-set, we examined how many older adults think about suicide over a one-year period, why they think about suicide, and whether living arrangements are associated with suicidal ideation. Results: About 1 out of 12 respondents in our sample reported suicidal ideation. While women and men did not differ in the prevalence of suicidal ideation, women attributed their suicidal feelings to health problems, while men attributed theirs to economic difficulties. Logistic regression results indicated that living arrangements are associated with suicidal ideation for men but not women. Older men living with a spouse were less likely to have suicidal ideation than older men with other living arrangements (i.e., living alone, living with children without spouse, living with spouse, and others). Conclusions: Our results highlight the importance of living arrangements to older mens suicidal ideation. We discuss gender differences in the implications of living arrangements to suicidal ideation within the context of Confucian culture.

Silver nanoparticles improve structural stability and biocompatibility of decellularized porcine liver

Abstract No ideal cross-linking agent has been identified for decellularized livers (DLs) yet. In this study, we evaluated structural improvements and biocompatibility of porcine DLs after cross-linking with silver nanoparticles (AgNPs). Porcine liver slices were decellularized and then loaded with AgNPs (100 nm) after optimization of the highest non-toxic concentration (5 µg/mL) using Human hepatocellular carcinoma (HepG2) and EAhy926 human endothelial cell lines. The cross-linking effect of AgNPs was evaluated and compared to that of glutaraldehyde and ethyl carbodiimide hydrochloride and N-hydroxysuccinimide. The results indicated that AgNPs improved the ultra-structure of DLs’ collagen fibres with good porosity and increased DLs’ resistance against in vitro degradation with good cytocompatibility. AgNPs decreased the host inflammatory reaction against implanted porcine DL slices in vivo and increased the polarization of M2 macrophages. Thus, structural and functional improvements of Porcine DLs could be achieved using AgNPs. Graphical Abstract The present study used 5 μg/mL silver nanoparticles (AgNPs) to cross-link the decellularized porcine liver slices. This method of cross-linking improved the structural stability and the degradation resistance of the decellularized porcine liver slices. It also increased the biocompatibility of the decellularized porcine liver slices compared with those of the non-cross-linked, glutaraldehyde or EDC/NHS cross-linked slices.

The association between the use of biomedical services and the holistic use of traditional East Asian medicine: a national survey of outpatients in South Korea

Objectives The holistic use of a system of complementary and alternative medicine (CAM) is potentially linked to its treatment outcomes. This paper examines how the use of biomedicine is associated with the holistic use of CAM, focusing on traditional East Asian medicine (EM) that is uniquely integrated in the medical system in South Korea. Design/Settings A representative national sample of EM outpatients in South Korea. Participants 3861 survey respondents. Methods By using the 2011 Korean National Survey of EM patients, ordered logistic regression models specify the relationship between EM outpatients’ use of biomedicine and their holistic use of EM modalities. Results Among EM outpatients who used at least one EM modality in the past 3 months, people who used two (33.3%) or three (29.4%) modalities together are the two highest proportions, followed by users of four (18.1%), five (7.2%), six (2.1%) and seven (0.6%) modalities. The odds for EM users to use EM holistically are 17% greater among EM users who used biomedicine as well, compared with EM users who did not use biomedicine. Conclusions The healthcare community should recognise that CAM use likely becomes holistic as people use biomedicine concomitantly, when the practice rights over a CAM system are comprehensively and exclusively entitled to a group of CAM professionals who are independent from practitioners of biomedicine.

Separate but Near: Senior Parents’ Living Arrangement and Married Women’s Employment in South Korea

It is well documented that co-residence with senior parents increases the likelihood that married women join the labour force in East Asian countries, such as Japan, Taiwan and South Korea. Parents help their married daughters or daughters-in-law with family responsibilities, allowing them to work for pay. Extending this established hypothesis of parental living arrangement, I argue that parents living separate but near, as well as together, have similar positive implications for married women’s employment. I test this argument using the case of Korea. Analysing a Korean national representative sample of married couples, I find that married women receive manual help often from their parents living separate but near and so are more likely to work for pay. By living in the same neighbourhood, the two generations keep their privacy and still exchange their support with each other. The literature on married women’s employment and inter-generational support in East Asian countries should consider the distances of the households of the two generations, even though they live separate.

Marital Satisfaction among Korean Commuter Couples

In Korea, some dual-earner married couples, where both husbands and wives have careers, live separately because their workplaces are located too far for a daily commute. These “commuter couples” are on the rise all over the world. In general, physical closeness is important for the quality of the relationships; thus, marital satisfaction is one of the most important issues in the literature on commuter couples. While some studies found a lower quality of relationships among commuter couples, others found cohesive and trustful relationships in these couples. However, the existing studies were conducted mainly with convenience samples of specific occupational groups in developed countries. Using a recent representative sample of commuter couples in Korea, this study found that commuter couples report lower levels of marital satisfaction compared to typical dual-earner couples. Additionally, this study found that in commuter couples, wives feel less marital satisfaction compared to their husbands.

Is giving or receiving psychologically beneficial to older mothers in South Korea? Importance of marital status

ABSTRACT In order to understand intergenerational financial transfers and subjective well-being for older mothers, this study argues that marital status is an important factor to be considered. Using the first wave of the Korean Longitudinal Study of Aging (KLoSA), this study finds that married older mothers report higher levels of life satisfaction when they provide economic support but widowed older mothers feel higher levels of life satisfaction when they receive economic support. Also, regular or irregular financial support appears to also matter in the associations between financial support and life satisfaction. These findings suggest that married and widowed older mothers have different viewpoints about the parent-children relationship.