Evaluation of the Antiviral Activity of Tabamide A and Its Structural Derivatives against Influenza Virus.

Influenza viruses cause severe endemic respiratory infections in both humans and animals worldwide. The emergence of drug-resistant viral strains requires the development of new influenza therapeutics. Tabamide A (TA0), a phenolic compound isolated from tobacco leaves, is known to have antiviral activity. We investigated whether synthetic TA0 and its derivatives exhibit anti-influenza virus activity. Analysis of structure-activity relationship revealed that two hydroxyl groups and a double bond between C7 and C8 in TA0 are crucial for maintaining its antiviral action. Among its derivatives, TA25 showed seven-fold higher activity than TA0. Administration of TA0 or TA25 effectively increased survival rate and reduced weight loss of virus-infected mice. TA25 appears to act early in the viral infection cycle by inhibiting viral mRNA synthesis on the template-negative strand. Thus, the anti-influenza virus activity of TA0 can be expanded by application of its synthetic derivatives, which may aid in the development of novel antiviral therapeutics.

A randomized split-face comparative study of long-pulsed alexandrite plus low-fluence Nd:YAG laser versus pulsed-dye laser in the treatment of rosacea.

OBJECTIVES: To compare the effectiveness of long-pulsed alexandrite laser (LPAL) with that of pulsed-dye laser (PDL) for rosacea. METHODS: This was a single-blind randomized controlled trial on 27 patients who were clinically diagnosed with rosacea. Randomly assigned split face in each patient received four times monthly treatment of LPAL plus low-fluence Nd:YAG with the contralateral side serving as the control treated with PDL. At every visit, the erythema index (EI) was measured with skin analysis systems, and two independent dermatologists evaluated digital photographs for five-point global aesthetic improvement scale (GAIS). RESULTS: The EI significantly decreased on both treated sides (LPAL 366.5 ± 101.0 vs. 295.8 ± 90.2, p < 0.001, PDL 369.0 ± 124.3 vs. 302.7 ± 92.1, p < 0.001) 1 month after fourth treatment (visit 5). Also 3 months after the fourth treatment (visit 6), the reduction in the EI was well maintained on both sides (LPAL 360.3 ± 96.8 vs. 282.0 ± 89.2, p < 0.001, PDL 364.3 ± 121.6 vs. 281.6 ± 97.8, p < 0.001). When comparing the improvement in the EI between the two groups, the percentage reduction in the EI on the LPAL-treated side was not inferior to the PDL-treated side (visit 5: LPAL 18.7 ± 15.7% vs. PDL 16.4 ± 12.9%, p = 0.501 and visit 6: LPAL 21.7 ± 13.9% vs. PDL 21.9 ± 15.2%, p = 0.943). The GAIS and patient satisfaction were comparable between the LPAL and PDL sides and did not show any significant difference. No serious adverse events occurred on either of the treated sides. CONCLUSION: This study showed that the decrease in EI in the treatment of rosacea was comparable between PDL and LPAL. Therefore, LPAL could be a promising alternative treatment option with good merits for rosacea, considering no consumables are required for device maintenance.

Incidence and death rate of sarcoidosis in Korea in association with metabolic diseases.

Sarcoidosis is a systemic granulomatous disease that affects a variety of organs. Although the etiology has not been fully understood, it is thought that diverse genetic and environmental factors interact with the immune system to develop granulomas. The incidence and death rate of sarcoidosis vary according to race. This study was conducted to identify the epidemiology of sarcoidosis in Korea and reveal its association with comorbid diseases such as diabetes mellitus, hypertension, and dyslipidemia in a population-based database. We retrospectively analyzed Korean National Health Insurance claims data between 2006 and 2017. The average annual incidence from 2006 to 2017 was 0.82/100 000 person-years and the all-cause death rate in sarcoidosis patients was 9.25/1000 cases. The incidence of sarcoidosis was higher in patients with diabetes mellitus, hypertension, and dyslipidemia than patients without those underlying diseases. Sarcoidosis patients with diabetes mellitus and hypertension showed an increased death rate after adjusting the confounding factors (hazard ratio [95% confidence interval], 1.66 [1.23-2.23] and 1.73 [1.29-2.31] respectively), however, patients with dyslipidemia showed a low death rate (HR = 0.64 [0.46-0.88]). In conclusion, we found that sarcoidosis is associated with diabetes mellitus, hypertension, and dyslipidemia and that diabetes mellitus and hypertension increase the risk of death in sarcoidosis patients. Extra caution is needed in sarcoidosis patients who already have these metabolic diseases.

Preischemic Treadmill Exercise Ameliorates Memory Impairment and Microvasculature Damage in Rat Model of Chronic Cerebral Hypoperfusion.

PURPOSE: Silent information regulator 1 (SIRT1) in the brain is essential for maintaining cellular homeostasis and plays a neuroprotective role in cerebral ischemia and neurodegenerative disorders. The effect of preischemic treadmill exercise on chronic cerebral hypoperfusion (CCH)-induced spatial learning memory impairment, microvascular injury, and blood-brain barrier (BBB) disruption in relation with SIRT1 expression was evaluated. METHODS: Prior to bilateral common carotid artery occlusion (BCCAO) surgery, the rats in the exercise groups performed low-intensity treadmill running for 30 minutes once daily during 8 weeks. BCCAO surgery was performed on male Wistar rats at 12 weeks of age. Spatial learning memory was measured using the Morris water maze test. Neuronal nuclear antigen, SIRT1, and rat endothelial cells antigen 1 were determined by immunohistochemistry and platelet-derived growth factor receptor beta was determined by immunofluorescence. RESULTS: Preischemic treadmill exercise ameliorated spatial learning memory impairment and enhanced SIRT1 expression in the BCCAO rats. Preischemic treadmill exercise ameliorated BCCAO-induced damage to microvasculature and pericytes that make up the BBB. The effect of preischemic treadmill exercise was lost with sirtinol treatment. CONCLUSION: These results can apply treadmill exercise prior to cerebral ischemia as a rational preventive and therapeutic intervention strategy to improve cognitive dysfunction in CCH patients.

Low-intensity treadmill exercise protects cognitive impairment by enhancing cerebellar mitochondrial calcium retention capacity in a rat model of chronic cerebral hypoperfusion.

Chronic cerebral hypoperfusion (CCH) is caused by reduced blood flow to the brain representing gradually cognitive impairment. CCH induces mitochondrial dysfunction and neuronal cell death in the brain. Exercise is known to have a neuroprotective effect on brain damage and cognitive dysfunction. This study aimed to clarify the neuroprotective effect of low-intensity treadmill exercise (LITE) by enhancing cerebellar mitochondrial calcium retention capacity in an animal model of CCH. Wistar rats were divided into the sham group, the bilateral common carotid arteries occlusion (BCCAO) group, and the BCCAO and treadmill exercise (BCCAO+Ex) group. BCCAO+Ex group engaged the LITE on a treadmill for 30 min once a day for 8 weeks before the BCCAO surgery to investigate the protective effect of LITE on cognitive impairment. CCH induced by BCCAO resulted in mitochondrial dysfunction in the cerebellum, including impaired calcium homeostasis. CCH also decreased cerebellar Purkinje cells including of calbindin D28k and parvalbumin, resulting in cognitive impairment. The impairment of mitochondrial function, loss of cerebellar Purkinje cells, and cognitive dysfunction ameliorated by exercise. The present study showed that LITE hindered the deficit of spatial working memory and loss of Purkinje cell in the cerebellum induced by CCH. We confirmed that the protective effect of LITE on Purkinje cell by enhanced the mitochondrial calcium retention capacity. We suggest that LITE may protect against cognitive impairment, and further studies are needed to develop the intervention for patients who suffered from CCH.

A Phase II Multi-Center, Non-Randomized, Parallel Group, Non-Inferiority Study to Compare the Efficacy of No Radioactive Iodine Remnant Ablation to Remnant Ablation Treatment in Low- to Intermediate-Risk of Papillary Thyroid Cancer: The MOREthyroid Trial Protocol.

BACKGROUND: Radioactive iodine (RAI) remnant ablation is recommended in patients with papillary thyroid cancer (PTC) and extrathyroidal extension or central lymph node metastasis. However, there exists little evidence about the necessity of remnant ablation in PTC patients with low- to intermediate-risk, those have been increasing in recent decades. METHODS: This multicenter, prospective, non-randomized, parallel group clinical trial will enroll 310 eligible patients with low- to intermediate-risk of thyroid cancer. Inclusion criteria are patients who recently underwent total thyroidectomy for PTC with 3 or less tumors of size 1≤ to ≤2 cm with no microscopic extension and N0/x, or size ≤2 cm with microscopic extension and/or N1a (number of lymph node ≤3, size of tumor foci ≤0.2 cm, and lymph node ratio <0.4). Patients choose to undergo RAI ablation (131I, dose 1.1 GBq) or diagnostic whole-body scan (DxWBS) (131I or 123I, dose 0.074 to 0.222 GBq), followed by subsequent measurement of stimulated thyroglobulin (sTg) within 1 year. Survey for quality of life (QOL) will be performed at baseline and at 1 year after follow-up. The total enrollment period is 5 years, and patients will be followed up for 1 year. The primary endpoint is the non-inferiority of surgery alone to surgery with ablation in terms of biochemical remission (BCR) rate (sTg ≤2 ng/mL) without evidence of structural recurrence. The secondary endpoint was the difference of QOL. CONCLUSION: This study will evaluate whether surgery alone achieves similar BCR and improved QOL compared to RAI ablation in patients with low- to intermediate-risk PTC within 1 year.

Chemerin Treatment Inhibits the Growth and Bone Invasion of Breast Cancer Cells.

Chemerin is secreted as prochemerin from various cell types and then cleaved into the bioactive isoform by specific proteases. In various cancer types, chemerin exhibits pro- or antitumor effects. In the present study, chemerin treatment significantly inhibited the viability and invasion of breast cancer cells in the absence or presence of transforming growth factor (TGF)-ß and insulin-like growth factor (IGF)-1. The expression levels of E-cadherin and vimentin were reduced in chemerin-treated breast cancer cells. However, chemerin treatment recovered the reduced E-cadherin expression level in breast cancer cells treated with TGF-ß or IGF-1. Chemerin treatment inhibited nuclear ß-catenin levels in breast cancer cells stimulated with or without TGF-ß or IGF-1. In addition, chemerin treatment blocked the increase in the receptor activator of nuclear factor kappa-Β ligand (RANKL)/osteoprotegerin (OPG) ratio in osteoblastic cells exposed to metastatic breast cancer cell-derived conditioned medium. Chemerin treatment inhibited RANKL-induced osteoclast formation and bone resorption by reducing the secretion of matrix metalloproteinase (MMP)-2, MMP-9, and cathepsin K. Intraperitoneal administration of chemerin inhibited tumor growth in MCF-7 breast cancer cell-injected mice and reduced the development of osteolytic lesions resulting from intratibial inoculation of MDA-MB-231 cells. Taken together, chemerin inhibits the growth and invasion of breast cancer cells and prevents bone loss resulting from breast cancer cells by inhibiting finally osteoclast formation and activity.

Comparison of rivaroxaban and dalteparin for the long-term treatment of venous thromboembolism in patients with gynecologic cancers.

OBJECTIVES: Two randomized, controlled studies comparing outcomes in patients treated with direct oral anticoagulants or low-molecular weight heparin for cancer-associated venous thromboembolism (VTE) have previously been performed. However, gynecologic cancers accounted for approximately 10% of the study populations. We compared the outcomes of patients with primary gynecological cancers who were treated for cancer-associated VTE with either rivaroxaban or dalteparin. METHODS: The 162 eligible patients with gynecologic cancers who were treated with either dalteparin (n=60) or rivaroxaban (n=102) were reviewed. The primary outcome was a composite event, which included recurrence or clinically relevant bleeding events during the therapeutic period. Secondary outcomes were recurrence, clinically relevant bleeding events, and mortality. RESULTS: During the therapeutic period, there were no significant differences between the groups in the proportion of composite events, recurrence, or clinically relevant bleeding. Multivariate analysis using the Cox proportional hazards model also showed no significant difference in the number of composite events and clinically relevant bleeding between the groups. In the rivaroxaban group, 44.0% of patients experienced gastrointestinal bleeding and 24.0% experienced urinary tract bleeding. In the dalteparin group, bleeding was most common in the urinary tract (44.4%) and at the injection site (22.2%). CONCLUSION: In this study, although there were no significant differences in effectiveness or safety between the rivaroxaban and dalteparin groups, rivaroxaban use was associated with a higher rate of clinically relevant bleeding than dalteparin. Therefore, caution should be taken when prescribing rivaroxaban for gynecologic cancer-associated VTE and bleeding events should be carefully monitored.

Cell-Membrane-Cloaked Oil Nanosponges Enable Dual-Modal Detoxification.

The lack of pharmaceutical antidotes for deadly toxicants has motivated tremendous research interests in seeking synthetic nanoscavengers to absorb and neutralize harmful biological or chemical agents. Herein, we report a cell-membrane-cloaked oil nanosponge formulation capable of dual-modal detoxification. The biomimetic oil nanosponge consists of an olive oil nanodroplet wrapped by a red blood cell membrane. In such a construct, the oil core can nonspecifically soak up toxicants through physical partition and the cell membrane shell can specifically absorb and neutralize toxicants through biological binding. The dual-modal detoxification capability of the oil nanosponges was validated using three distinct organophosphates (OPs), including paraoxon, diisopropyl fluorophosphate, and dichlorvos. By inhibiting acetylcholinesterase, OPs cause the accumulation of acetylcholine, which leads to neuromuscular disorders and even death. In mouse models of OP poisoning, the oil nanosponges reduced clinical signs of OP intoxication, lowered OP concentration in tissues, and greatly enhanced mouse survival in both the therapeutic regimen and the prophylactic regimen. Overall, oil nanosponges combine the merits of both cell membrane and oil nanodroplets for safe and effective detoxification, which also serve as a prototype of multimodal detoxification platforms.

Ulmus macrocarpa Hance modulates lipid metabolism in hyperlipidemia via activation of AMPK pathway.

Ulmus macrocarpa Hance as an oriental medicinal plant has shown enormous potential for the treatment of several metabolic disorders in Korea. Hyperlipidemia, which is characterized by the excess accumulation of lipid contents in the bloodstream, may lead to several cardiovascular diseases. Therefore, in this study, anti-hyperlipidemic potential of U. macrocarpa water extract (UME) was examined in vitro and in vivo using HepG2 cells and experimental rats, respectively. The hyperlipidemia in experimental rats was induced by the high-cholesterol diet (HCD) followed by oral administration of various concentrations (25, 50 and 100 mg/kg) of UME for 6 weeks. As a result, the UME significantly improved the biochemical parameters such as increased the level of triglyceride, total cholesterol, and low-density lipoprotein cholesterol as well as reduced the high-density lipoprotein cholesterol in the HCD-fed rats. In addition, UME also prevented lipid accumulation through regulating AMPK activity and lipid metabolism proteins (ACC, SREBP1 and HMGCR) in the HCD-fed rats as compared to the controls. Moreover, similar pattern of gene expression levels was confirmed in oleic acid (OA)-treated HepG2 cells. Taken together, our results indicate that UME prevents hyperlipidemia via activating the AMPK pathway and regulates lipid metabolism. Thus, based on the above findings, it is estimated that UME could be a potential therapeutic agent for preventing the hyperlipidemia.

Factors affecting KRAS mutation detection in colorectal cancer tissue.

BACKGROUND: With the recent development of molecular tests for various biomarkers, it has become even more important to prepare adequate tissue samples. However, little is known about how the effect of cold ischemia time or formalin fixation time can affect KRAS mutation detection in colorectal cancer. METHODS: This study included the results of KRAS mutation tests for colorectal cancer in 401 specimens. We investigated clinicopathologic factors that may affect DNA quality of formalin-fixed, paraffin-embedded (FFPE) tissue including specimen type, cold ischemia time, and formalin fixation time and assessed the detection rate of the KRAS mutation in samples with varying DNA quality. RESULTS: Sample DNA quality for KRAS mutation test was better in biopsy specimens, which showed markedly shorter cold ischemia time and shorter formalin fixation time compared to resection specimens. A cold ischemia time of one hour or less was associated with better sample DNA quality. But the formalin fixation time was not a significant factor when it fell within the range performed in routine pathology diagnosis. When prolonged formalin fixation was tested, we confirmed that the specimen DNA quality gradually got worse from one month to three months. CONCLUSIONS: The biopsy specimens showed better sample DNA quality for KRAS mutation test compared to resection specimens. In a routine diagnostic pathology setting, the cold ischemia time was an important factor affecting DNA quality and the formalin fixation had a wide time range for optimal DNA quality.

Birt-Hogg-Dubé syndrome in Korean: clinicoradiologic features and long term follow-up.

BACKGROUND/AIMS: Birt-Hogg-Dubé (BHD) syndrome is a rare autosomal dominant disorder that is characterized by skin fibrofolliculomas, pulmonary cysts, and renal tumors. The objective of this study was to describe the features of Korean patients with BHD syndrome. METHODS: Clinical data were retrospectively reviewed in 12 patients (10 confirmed by direct sequencing of the folliculin (FLCN) gene and two confirmed by clinical diagnosis) diagnosed from 2004 to 2016 at Asan Medical Center, Seoul, South Korea. Criteria proposed by the European BHD consortium were used for diagnosis. RESULTS: The median follow-up was 52 months. The mean age was 41.3 years and 66.7% were female. Eight patients (66.7%) had a history of pneumothorax, which was recurrent in 75%. Skin lesions were detected in 25.0% and renal cancer in 25.0%. Among mutations of the FLCN gene, the duplication of cytosine in the C8 tract of exon 11 (c.1285dupC) was the most common (40%); however, a novel heterozygous sequence variant of c.31T>C (p.C11R) in exon 4 was detected in one patient. All patients had multiple and bilateral pulmonary cysts, distributed in predominantly lower, peripheral and subpleural regions of the lungs. Most patients showed preserved lung function that remained unchanged during follow-up, and two (16.7%) developed cancers (renal cancer in one and breast cancer in one). CONCLUSION: Our data suggest that Korean patients with BHD syndrome may have a higher risk of pneumothorax, less frequent skin lesions, and a novel FLCN mutation compared to previous reports. Multiple bilateral and basal-predominant cysts were the most common radiologic features.

TGF-ß2 downregulates osteogenesis under inflammatory conditions in dental follicle stem cells.

Bone formation is important for the reconstruction of bone-related structures in areas that have been damaged by inflammation. Inflammatory conditions such as those that occur in patients with rheumatoid arthritis, cystic fibrosis, and periodontitis have been shown to inhibit osteoblastic differentiation. This study focussed on dental follicle stem cells (DFSCs), which are found in developing tooth germ and participate in the reconstruction of alveolar bone and periodontal tissue in periodontal disease. After bacterial infection of inflamed dental tissue, the destruction of bone was observed. Currently, little is known about the relationship between the inflammatory environment and bone formation. Osteogenic differentiation of inflamed DFSCs resulted in decreased alkaline phosphatase (ALP) activity and alizarin red S staining compared to normal DFSCs. Additionally, in vivo transplantation of inflamed and normal DFSCs demonstrated severe impairment of osteogenesis by inflamed DFSCs. Protein profile analysis via liquid chromatography coupled with tandem mass spectrometry was performed to analyse the differences in protein expression in inflamed and normal tissue. Comparison of inflamed and normal DFSCs showed significant changes in the level of expression of transforming growth factor (TGF)-ß2. Porphyromonas gingivalis (P.g.)-derived lipopolysaccharide (LPS) was used to create in vitro inflammatory conditions similar to periodontitis. The osteogenic differentiation of LPS-treated DFSCs was suppressed, and the cells displayed low levels of TGF-ß1 and high levels of TGF-ß2. DFSCs treated with TGF-ß2 inhibitors showed significant increases in alizarin red S staining and ALP activity. TGF-ß1 expression was also increased after inhibition of TGF-ß2. By examining inflamed DFSCs and LPS-triggered DFSCs, these studies showed both clinically and experimentally that the increase in TGF-ß2 levels that occurs under inflammatory conditions inhibits bone formation.

Platycarya strobilacea leaf extract inhibits tumor necrosis factor-α production and bone loss induced by Porphyromonas gingivalis-derived lipopolysaccharide.

OBJECTIVE: Remodeling of alveolar bone is controlled by osteoclast-mediated bone resorption and osteoblast-induced bone formation. LPS of Porphyromonas gingivalis, a major causative agent of periodontitis, produces proinflammatory cytokines in host immune cells, which thereby triggers osteoclastogenesis and leads to alveolar bone resorption. We investigated the anti-periodontitis potential of Platycarya strobilacea leaf extract (PLE), which is used as a traditional medicine in Asian countries. DESIGN: TNF-α levels in cell culture media were measured using a commercially available enzyme-linked immunosorbent assay kit. Osteoclast differentiation was observed by tartrate-resistant acid phosphatase staining, and the expression levels of osteoclastogenic genes were measured by quantitative real-time PCR. Bone-resorbing activity was confirmed by the resorption pit formation, gelatin zymographic, and the cathepsin K activity assays. Osteogenic differentiation was confirmed with an ALP activity assay and alizarin red S staining. RESULTS: PLE treatment inhibited the production of TNF-α in P. gingivalis LPS-stimulated RAW264.7 macrophages. In bone marrow-derived macrophages serving as osteoclast precursors, PLE treatment blocked RANKL-induced osteoclastogenesis and gene expression levels of the osteoclastogenic transcription factor NFATc1, DC-STAMP for osteoclast fusion, and cathepsin K for osteoclast activity. In addition, PLE treatment reduced the formation of resorption pits and the secretion of MMP 9 and cathepsin K from the differentiated osteoclasts. Furthermore, PLE treatment induced osteogenesis by increasing ALP activity and calcium content in preosteoblastic cells. CONCLUSION: PLE inhibits P. gingivalis LPS-induced TNF-α production and bone resorption and induces bone formation. PLE may be a beneficial agent to promote oral health by inhibiting periodontitis-induced alveolar bone loss.

Comparison of the clinical performance of OmniPlex-HPV and GeneFinder HPV for the detection and genotyping of human papillomaviruses in cervical specimens.

PURPOSE: Human papillomavirus (HPV) infection in women is known to promote the development of cervical neoplasia. Specific HPV genotypes are more highly associated with disease, and therefore detection and genotyping of HPV infection is critical for preventing and effectively treating cervical cancer. Consequently, various assays using diverse technologies have been developed to detect HPV genotype. Recently the OmniPlex-HPV and GeneFinder HPV methods, based on PCR and Luminex xMAP liquid bead microarray technologies, were developed for the detection of 40 and 32 HPV genotypes, respectively. The purpose of this study was to compare the clinical performance of OmniPlex-HPV and GeneFinder HPV. METHODOLOGY: The study included 300 cytology-confirmed cervical swab specimens. In cases where there was a discrepancy between the two assay results, type-specific direct sequencing was performed. RESULT: We found a high overall agreement between OmniPlex-HPV and GeneFinder HPV for detecting the presence or absence of high-risk HPV (HR HPV) (90.7 %, κ=0.810). However, OmniPlex-HPV showed greater sensitivity than GeneFinder HPV in the identification of multiple genotype-infected samples. Specifically, diagnostic sensitivities for HR HPV positivity in high-grade squamous intra-epithelial lesions (HSIL) were 100.0 % for OmniPlex-HPV and 96.8 % for GeneFinder HPV. CONCLUSIONS: Our results suggest that OmniPlex-HPV and GeneFinder HPV are highly comparable for the detection and genotyping of HPV, but OmniPlex-HPV displays greater accuracy in cases of multiple HPV infection.

Pancreatic DCLK1+ cells originate distinctly from PDX1+ progenitors and contribute to the initiation of intraductal papillary mucinous neoplasm in mice.

PanINs and IPMNs are the two most common precursor lesions that can progress to invasive pancreatic ductal adenocarcinoma (PDA). DCLK1 has been identified as a biomarker of progenitor cells in PDA progressed from PanINs. To explore the potential role of DCLK1-expressing cells in the genesis of IPMNs, we compared the incidence of DCLK1-positive cells in pancreatic tissue samples from genetically-engineered mouse models (GEMMs) for IPMNs, PanINs, and acinar to ductal metaplasia by immunohistochemistry and immunofluorescence. Mouse lineage tracing experiments in the IPMN GEMM showed that DCLK1+ cells originated from a cell lineage distinct from PDX1+ progenitors. The DCLK1+ cells shared the features of tuft cells but were devoid of IPMN tumor biomarkers. The DCLK1+ cells were detected in the earliest proliferative acinar clusters prior to the formation of metaplastic ductal cells, and were enriched in the "IPMN niches". In summary, DCLK1 labels a unique pancreatic cellular lineage in the IPMN GEMM. The clustering of DCLK1+ cells is an early event in Kras-induced pancreatic tumorigenesis and may contribute to IPMN initiation.

TSG-6 secreted by mesenchymal stem cells suppresses immune reactions influenced by BMP-2 through p38 and MEK mitogen-activated protein kinase pathway.

Bone morphogenetic protein 2 (BMP-2) has a critical function in bone and cartilage development and in repairing damaged organs and tissue. However, clinical use of BMP-2 at doses of 0.5-1 mg/ml for orthopedics has been associated with severe postoperative swelling requiring emergency surgical intervention. We determined whether a high concentration of BMP-2 induces inflammatory responses in macrophages and the suppression of osteogenesis in hMSCs. We obtained human periodontal ligament stem cells and bone marrow stem cells from the maxilla, i.e., human mesenchymal stem cells (hMSCs), from the periodontal ligament of extracted third molar teeth and from the bone marrow of the maxilla, respectively. Osteogenic differentiation was measured by alkaline phosphatase activity and alizarin red S staining. Proteins were assessed by flow cytometry, enzyme-linked immunosorbent assay, Western blot and immunocytochemistry. Changes of gene expression were measured by reverse transcription plus the polymerase chain reaction (RT-PCR) and real-time PCR. A high BMP-2 concentration inhibited the early stages of osteogenesis in hMSCs. Co-culturing THP-1 cells (human monocytic cells) with hMSCs reduced the late stages of osteogenesis compared with those seen in hMSCs alone. In addition, high-dose BMP-2 induced the expression of inflammatory cytokines in THP-1 cells and the expression of the anti-inflammatory cytokine tumor-necrosis-factor-α-inducible gene 6 protein (TSG-6) in hMSCs. Consistent with the anti-inflammatory effects of hMSCs when co-cultured with THP-1 cells, interleukin-1ß expression was downregulated by TSG-6 treatment of THP-1 cells. Our findings suggest that a high BMP-2 concentration triggers inflammation that causes inflammatory cytokine release from THP-1 cells, leading to the suppression of osteogenesis, whereas TSG-6 secreted by hMSCs suppresses inflammatory reactions through p38 and ERK in the mitogen-activated protein kinase pathway.