Brain diseases and damages come in many forms such as neurodegenerative diseases, tumors, and stroke. Millions of people currently suffer from neurological diseases worldwide. While Challenges of current diagnosis and treatment for neurological diseases are the drug delivery to the central nervous system. The Blood–Brain Barrier (BBB) limits the drug from reaching the targeted site thus showing poor effects. Nanoparticles that have advantage of the assembly at the nanoscale of available biomaterials can provide a delivery platform with potential to raising brain levels of either imaging therapeutic drugs or imaging. Therefore, successful modeling of the BBB is another crucial factor for the development of nanodrugs. In this review, we analyze the in vitro and in vivo findings achieved in various models, and outlook future development of nanodrugs for the successful treatment of brain diseases and damages.

For the cartilage repair, the cell sources currently adopted are primarily chondrocytes or mesenchymal stem cells (MSCs). Due to the fact that chondrocytes dedifferentiate during 2-dimensional (2D) expansion, MSCs are generally more studied and considered to have higher potential for cartilage repair purposes. Here we question if the dedifferentiated chondrocytes can regain the chondrogenic potential, to find potential applications in cartilage repair. For this we chose chondrocytes at passage 12 (considered to have sufficiently dedifferentiated) and the expression of chondrogenic phenotypes and matrix syntheses were examined over 14 days. In particular, the chondrogenic potential of MSCs was also compared. Results showed that the dedifferentiated chondrocytes proliferated actively over 14 days with almost 2.5-fold increase relative to MSCs. Moreover, the chondrogenic ability of chondrocytes was significantly higher than that of MSCs, as confirmed by the expression of a series of mRNA levels and the production of cartilage extracellular matrix molecules in 2D-monolayer and 3-dimensional (3D)-spheroid cultures. Of note, the significance was higher in 3D-culture than in 2D-culture. Although more studies are needed such as the use of different cell passages and human cell source, and the chondrogenic confirmation under in vivo conditions, this study showing that the dedifferentiated chondrocytes can also be a suitable cell source for the cell-based cartilage repair, as a counterpart of MSCs, will encourage further studies regarding this issue.
Animals ; Cartilage ; Chondrocytes* ; Chondrogenesis ; Extracellular Matrix ; Humans ; Mesenchymal Stromal Cells ; Phenotype ; Rats* ; RNA, Messenger

BACKGROUND: It has been reported that long working hours are hazardous to the workers’ health. Especially, work-related musculoskeletal disorders (WMSDs) have been considered as one of the significant health issues in workplace. The objective of this study was to identify the association between long working hours and work-related musculoskeletal symptoms. METHODS: The analysis was conducted using data from the Fourth Korean Working Conditions Survey (KWCS). Subjects of this study were 24,783 wage workers and divided into three groups according to the weekly working hours, which were ≤ 40, 41–52 and > 52 h. The relationship between long working hours and work-related musculoskeletal symptoms was analyzed by multivariate logistic regression method after adjusting for general, occupational characteristics including specific working motions or postures and psychosocial factors. RESULTS: Approximately 18.4% of subjects worked more than 52 h per week and 26.4 and 16.4% of male subjects and 33.0 and 23.4% of female subjects experienced work-related upper and lower limb pains, respectively, over the last 12 months. Moreover, the prevalence of upper and lower limb pain was increased in both genders as the weekly working hours increased. The odds ratios (ORs) of upper limb pain for those working 41–52 h and more than 52 h per week when adjusted for general, occupational characteristics including specific motions or postures and psychosocial factors were 1.36 and 1.40 for male workers and 1.26 and 1.66 for female workers compared to the reference group, respectively. Furthermore, ORs of lower limb pain for the same weekly working hour groups were 1.26 and 1.47 for male workers and 1.20 and 1.47 for female workers, respectively. CONCLUSIONS: Long working hours were significantly related to work-related musculoskeletal symptoms in Korean wage workers and appropriate interventions should be implemented to reduce long working hours that can negatively affect workers’ health.
Female ; Humans ; Logistic Models ; Lower Extremity ; Male ; Methods ; Odds Ratio ; Posture ; Prevalence ; Psychology ; Salaries and Fringe Benefits ; Upper Extremity

BACKGROUND: In modern society, the scale of the service industry is continuously expanding, and the number of service workers is increasing. Correspondingly, physical and mental problems related to emotional labor are becoming a major social problem. In this study, we investigated the relationship between emotional labor, workplace violence, and depressive symptoms in female bank employees, which is a typical service industry. METHODS: In this study, the Korean Emotional Labor Scale (K-ELS) and Korean Workplace Violence Scale (K-WVS) were distributed to 381 female workers in their 20s at a bank in Seoul, Korea. Data were obtained from 289 subjects (75.9%) and analyzed for 278 respondents, after excluding those with missing responses. We examined the relationship between emotional labor, workplace violence, and depressive symptoms, using multiple logistic regression analysis. RESULTS: Among 278 subjects, 27 workers (9.7%) had depressive symptoms. “Emotional disharmony and hurt” (OR 2.93, 95% CI = 1.17–7.36) and “Organizational surveillance and monitoring” (OR 3.18, 95% CI = 1.29–7.86) showed a significant association with depressive symptoms. For workplace violence, the “Experience of psychological and sexual violence from supervisors and coworkers” (OR 4.07, 95% CI = 1.58–10.50) showed a significant association. When the number of high-risk emotional labor-related factors was 1 or more, 13.1% showed depressive symptoms. When the number of high-risk workplace violence-related factors was 1 or more, 14.4% had statistically significant depressive symptoms. CONCLUSIONS: A significant result was found for depressive symptoms related to Emotional disharmony, which is a sub-topic of emotional labor, and those at high risk for “Organizational surveillance and monitoring.” For workplace violence, depressive symptoms were high for the group at high risk for the “experience of psychological and sexual violence from supervisors and coworkers.” In this way, management of emotional disharmony, a sub-factor of emotional labor, is necessary, and improvements to traditional corporate culture that monitors emotional labor is necessary. Violence from colleagues and supervisors in the workplace must also be reduced. IRB Approval No. SCHUH 2017–01-029. Registered 26 January 2017. Retrospectively registered. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s40557-018-0229-9) contains supplementary material, which is available to authorized users.
Depression ; Ethics Committees, Research ; Female ; Humans ; Korea ; Logistic Models ; Organizational Culture ; Retrospective Studies ; Seoul ; Sex Offenses ; Social Problems ; Surveys and Questionnaires ; Violence ; Workplace Violence

BACKGROUND: Sleep disorders and depression/anxiety disorders are long-standing and significant problem for mental health. Also there are already known so many negative health effect of these disorders. But there were few studies to examine the association between activities outside work and forementioned disorders. So this study aimed the association of those things by using the Republic of Korean data. METHODS: Data from 32,232 wage workers were used in the 4th Korean Working Condition Survey. General and occupational characteristics, sleep disorders, depression/anxiety disorders and activities outside work are included in questionnaire. To find the relationship between activities outside work and sleep, depression/anxiety disorders, multivariate logistic regression analysis was used after adjusting for general and occupational characteristics. RESULTS: We observed that volunteer activities increased the odds ratio of both sleep disorders and depression/anxiety disorders(Odds ratio[OR] = 1.35, 95% confidence interval[CI]: 1.03–1.78 and OR = 1.54, 95% CI: 1.29–1.84, respectively). And self-development activities increase the odds ratio of sleep disorders(OR = 1.35, 95% CI: 1.17–1.57). Gardening activities lowered the odds ratio of depression/anxiety disorders(OR = 0.74, 95% CI: 0.59–0.94). CONCLUSION: Some of activities outside work were related to sleep disorders and depression/anxiety disorders among Korean wage workers. Our results showed negative health effect of some kinds of activities outside work such as volunteering and self-devlopment compared to other studies that emphasized positive effect of those activities for health.
Agriculture ; Anxiety ; Depression ; Gardening ; Leisure Activities ; Logistic Models ; Mental Health ; Odds Ratio ; Salaries and Fringe Benefits ; Sleep Wake Disorders ; Volunteers

BACKGROUND: Around the globe, discrimination has emerged as a social issue requiring serious consideration. From the perspective of public health, the impact of discrimination on the health of affected individuals is a subject of great importance. On the other hand, subjective well-being is a key indicator of an individual's physical, mental, and social health. The present study aims to analyze the relationship between Korean employed workers' subjective health and their exposure to perceived discrimination. METHODS: The Fourth Korean Working Conditions Survey (KWCS, 2014) was conducted on a representative sample of the economically active population aged 15 years or older, who were either employees or self-employed at the time of interview. After removing inconsistent data, 32,984 employed workers were examined in this study. The data included general and occupational characteristics, perceived discrimination, and well-being. Well-being was measured through the WHO-Five index (1998 version). Multiple logistic regression analysis was used to examine the association between perceived discrimination and well-being. RESULT: As a group, employed workers who were exposed to discrimination had a significantly higher likelihood of “poor well-being” than their counterparts who were not exposed to discrimination. More specifically, the workers exposed to age discrimination had an odds ratio(OR) of 1.51 (95% CI: 1.36–1.68), workers exposed to discrimination based on educational attainment had an OR of 1.43 (95% CI: 1.26–1.61), and workers exposed to discrimination based on employment type had an OR of 1.68 (95% CI: 1.48–1.91) with respect to poor well-being. Furthermore, workers exposed to a greater number of discriminatory incidents were also at a higher risk of “poor well-being” than their counterparts who were exposed to fewer such incidents. More specifically, the workers with three exposures to discrimination had an OR of 2.60 (95% CI: 1.92–3.53), the workers with two such exposures had an OR of 1.69 (95% CI: 1.44–1.99), and the workers with one such exposure had an OR of 1.32 (95% CI: 1.20–1.45). CONCLUSION: The present study found that discrimination based on age, educational attainment, or employment type put workers at a higher risk of “poor well-being,” and that the greater the exposure to discrimination, the higher the risk of poor well-being.
Ageism ; Diagnostic Self Evaluation ; Discrimination (Psychology) ; Employment ; Hand ; Logistic Models ; Public Health

It is controversial whether type I collagen itself can maintain and improve chondrogenic phenotype of chondrocytes in a three-dimensional (3D) environment. In this study, we examined the effect of type I collagen concentration in hydrogel (0.5, 1, and 2 mg/ml) on the growth and phenotype expression of rat chondrocytes in vitro. All collagen hydrogels showed substantial contractions during culture, in a concentration-dependent manner, which was due to the cell proliferation. The cell viability was shown to be the highest in 2 mg/ml collagen gel. The mRNA expression of chondrogenic phenotypes, including SOX9, type II collagen, and aggrecan, was significantly up-regulated, particularly in 1 mg/ml collagen gel. Furthermore, the production of type II collagen and glycosaminoglycan (GAG) content was also enhanced. The results suggest that type I collagen hydrogel is not detrimental to, but may be useful for, the chondrocyte culture for cartilage tissue engineering.
Aggrecans ; Animals ; Cartilage ; Cell Proliferation ; Cell Survival ; Chondrocytes* ; Collagen ; Collagen Type I* ; Collagen Type II ; Hydrogel* ; Hydrogels ; In Vitro Techniques ; Phenotype ; Rats* ; RNA, Messenger ; Tissue Engineering

Delivery of stem cells with osteogenesis while enabling angiogenesis is important for vascularized bone tissue engineering. Here a three-dimensional (3D) co-culture system of dental pulp stem cells (DPSCs) and endothelial cells (ECs) was designed using porous microcarriers, and the feasibility of applying to bone tissue engineering was investigated in vitro. Highly porous spherical microcarriers made of degradable biopolymers were prepared with sizes of hundreds of micrometers. The microcarriers loaded with DPSCs were co-cultured with ECs embedded in a hydrogel of type I collagen. An optimal coculture medium that preserves the viability of ECs while stimulating the osteogenic differentiation of DPSCs was found to be a 10:1 of osteogenic medium:endothelial medium. The co-cultured constructs of DPSCs/ECs showed significantly higher level of alkaline phosphatase activity than the mono-cultured cells. Moreover, the expressions of genes related with osteogenesis and angiogenesis were significantly up-regulated by the co-cultures with respect to the mono-cultures. Results imply the interplay between ECs and DPSCs through the designed 3D co-culture models. The microcarrier-enabled co-cultured cell system is considered to be useful as an alternative tool for future vascularized bone tissue engineering.
Alkaline Phosphatase ; Biopolymers* ; Bone and Bones* ; Coculture Techniques* ; Collagen Type I ; Dental Pulp* ; Endothelial Cells* ; Feasibility Studies* ; Humans* ; Hydrogel ; In Vitro Techniques ; Osteogenesis ; Stem Cells*

Articular cartilage has limited regeneration capacity, thus significant challenge has been made to restore the functions. The development of hydrogels that can encapsulate and multiply cells, and then effectively maintain the chondrocyte phenotype is a meaningful strategy to this cartilage repair. In this study, we prepared alginate-hyaluronic acid based hydrogel with type I collagen being incorporated, namely Alg-HA-Col composite hydrogel. The incorporation of Col enhanced the chemical interaction of molecules, and the thermal stability and dynamic mechanical properties of the resultant hydrogels. The primary chondrocytes isolated from rat cartilage were cultured within the composite hydrogel and the cell viability recorded revealed active proliferation over a period of 21 days. The mRNA levels of chondrocyte phenotypes, including SOX9, collagen type II, and aggrecan, were significantly up-regulated when the cells were cultured within the Alg-HA-Col gel than those cultured within the Alg-HA. Furthermore, the secretion of sulphated glycosaminoglycan, a cartilage-specific matrix molecule, was recorded higher in the collagen-added composite hydrogel. Although more in-depth studies are required such as the in vivo functions, the currently-prepared Alg-HA-Col composite hydrogel is considered to provide favorable 3-dimensional matrix conditions for the cultivation of chondrocytes. Moreover, the cell-cultured constructs may be useful for the cartilage repair and tissue engineering.
Aggrecans ; Animals ; Cartilage ; Cartilage, Articular ; Cell Survival ; Chondrocytes* ; Collagen Type I ; Collagen Type II ; Hyaluronic Acid ; Hydrogel* ; Hydrogels ; Phenotype* ; Rats ; Regeneration ; RNA, Messenger ; Tissue Engineering

Adipose-derived stem cells (ADSCs) are an attractive source of material for mesenchymal stem cell research due to the abundance of adipose and relative ease of access compared with bone marrow. A key consideration for research is whether cell isolation methods can be improved, to reduce the process steps needed to isolate and expand cell material. In the current study, we used macroporous biopolymer microcarriers to isolate primary ADSCs. We found that the method was capable of isolating ADSCs that were subsequently capable of being transferred to culture dishes and expanded in vitro. Moreover, flow cytometry revealed that they expressed typical stem cell markers and were capable of undergoing tri-lineage differentiation. In summary, it is feasible to use biopolymer microcarriers for retrieval of viable ADSCs that retain identity markers of stem cell function.
Adult Stem Cells ; Animals ; Biopolymers* ; Bone Marrow ; Cell Separation ; Flow Cytometry ; In Vitro Techniques ; Mesenchymal Stromal Cells ; Methods ; Rats* ; Stem Cells*