Circadian Rhythms in Tongue Features.

(1) Background: The aim of this study was to investigate the circadian rhythms of tongue features according to the effects of physiological phases over a 24 h period. (2) Methods: Fifteen healthy participants aged 20 to 69 years were recruited. The participants did not have current chronic diseases or past diseases and had to meet the inclusion and exclusion criteria. The participants stayed at the Gil Hospital for a duration of 2 nights and 3 days. On the first day, at 18:00, they consumed their allocated portions of food and water and then completed a questionnaire. At approximately 21:00, their tongue images were acquired using a computerized tongue image acquisition system, following which they slept for 8 h, commencing at 23:00. Measurements were taken from 07:00 through 21:00 on the second day, and the final acquisition was taken at 07:00 on the following morning, resulting in a total of eight images. The circadian rhythm was authenticated and quantified utilizing the single cosinor analysis, a technique for periodic regression analysis for fitting a 24 h cosine curve. (3) Results: Cosinor analysis revealed that all tongue features were significantly related to circadian rhythm. (4) Conclusions: The results of this study may be important for considering the time of day at which the tongue is observed and tongue status is evaluated.

Decellularized allogeneic cartilage paste with human costal cartilage and crosslinked hyaluronic acid-carboxymethyl cellulose carrier augments microfracture for improved articular cartilage repair.

Articular cartilage lacks natural healing abilities and necessitates surgical treatments for injuries. While microfracture (MF) is a primary surgical approach, it often results in the formation of unstable fibrocartilage. Delivering hyaline cartilage directly to defects poses challenges due to the limited availability of autologous cartilage and difficulties associated with allogeneic cartilage delivery. We developed a decellularized allogeneic cartilage paste (DACP) using human costal cartilage mixed with a crosslinked hyaluronic acid (HA)-carboxymethyl cellulose (CMC) carrier. The decellularized allogeneic cartilage preserved the extracellular matrix and the nanostructure of native hyaline cartilage. The crosslinked HA-CMC carrier provided shape retention and moldability. In vitro studies confirmed that DACP did not cause cytotoxicity and promoted migration, proliferation, and chondrogenic differentiation of human bone marrow-derived mesenchymal stem cells. After 6 months of implantation in rabbit knee osteochondral defects, DACP combined with MF outperformed MF alone, demonstrating improved gait performance, defect filling, morphology, extracellular matrix deposition, and biomechanical properties similar to native cartilage. Thus, DACP offers a safe and effective method for articular cartilage repair, representing a promising augmentation to MF. STATEMENT OF SIGNIFICANCE: Directly delivering hyaline cartilage to repair articular cartilage defects is an ideal treatment. However, current allogeneic cartilage products face delivery challenges. In this study, we developed a decellularized allogeneic cartilage paste (DACP) by mixing human costal cartilage with crosslinked hyaluronic acid (HA)-carboxymethyl cellulose (CMC). DACP preserves extracellular matrix components and nanostructures similar to native cartilage, with HA-CMC ensuring shape retention and moldability. Our study demonstrates improved cartilage repair by combining DACP with microfracture, compared to microfracture alone, in rabbit knee defects over 6 months. This is the first report showing better articular cartilage repair using decellularized allogeneic cartilage with microfracture, without the need for exogenous cells or bioactive substances.

Predicting of tunneling resistivity between adjacent nanosheets in graphene-polymer systems.

In this work, the tunneling resistivity between neighboring nanosheets in grapheme-polymer nanocomposites is expressed by a simple equation as a function of the characteristics of graphene and tunnels. This expression is obtained by connecting two advanced models for the conductivity of graphene-filled materials reflecting tunneling role and interphase area. The predictions of the applied models are linked to the tested data of several samples. The impressions of all factors on the tunneling resistivity are evaluated and interpreted using the suggested equation. The calculations of tunneling resistivity for the studied examples by the model and suggested equation demonstrate the same levels, which confirm the presented methodology. The results indicate that the tunneling resistivity decreases by super-conductive graphene, small tunneling width, numerous contacts among nanosheets and short tunneling length.

A Clinical Study on the Relationship Among Insomnia, Tongue Diagnosis, and Oral Microbiome.

Currently, there is a lack of adequate methods to assess insomnia objectively. This study addresses the usefulness of tongue features and oral microbial profile as a potential diagnostic biomarker of insomnia. One hundred insomniac patients and 20 healthy control subjects were selected. Their demographic and clinical characteristics, as well as the tongue diagnostic indices and oral microbial profile, were examined. Compared to the control group, insomniac patients showed a higher abnormal low-frequency/high-frequency (LF/HF) ratio. In tongue diagnosis, the indices related to lightness of tongue body and tongue coating were higher in the insomniac group vs. the control group. Furthermore, linear discriminant analysis (LDA) of oral microbial population revealed that the relative abundances of Clostridia, Veillonella, Bacillus and Lachnospiraceae were significantly higher in the insomniac patients than the control group. Additionally, the tongue features of the insomniac group exhibited that the non-coating group had a poor sleep condition compared to the thick-coating group, although the difference was insignificant. On the other hand, the oral microbial communities of the insomniac patients revealed greater alpha and beta diversities in the non-coating group vs. the thick-coating group. The alpha and beta diversities were higher in orotype1 than orotype2. Collectively, this study highlighted that the lightness of tongue body and tongue coating as well as oral microbial profiles of SR1, Actinobacteria, Clostridia and Lachnospiraceae_unclassified could be considered potential biomarkers of insomnia.

Bone Marrow Homeostasis Is Impaired via JAK/STAT and Glucocorticoid Signaling in Cancer Cachexia Model.

Cancer cachexia is a multifactorial systemic inflammation disease caused by complex interactions between the tumor and host tissues via soluble factors. However, whether cancer cachexia affects the bone marrow, in particular the hematopoietic stem cells (HSCs) and mesenchymal stem cells (MSCs), remains unclear. Here, we investigated the bone marrow and bone in a cancer cachexia animal model generated by transplanting Lewis lung carcinoma cells. The number of bone marrow mononuclear cells (BM-MNCs) started to significantly decrease in the cancer cachectic animal model prior to the discernable loss of muscle and fat. This decrease in BM-MNCs was associated with myeloid skewing in the circulation and the expansion of hematopoietic progenitors in the bone marrow. Bone loss occurred in the cancer cachexia animal model and accompanied the decrease in the bone marrow MSCs that play important roles in both supporting HSCs and maintaining bone homeostasis. Glucocorticoid signaling mediated the decrease in bone marrow MSCs in the cancer cachectic environment. The cancer cachexia environment also skewed the differentiation of the bone marrow MSCs toward adipogenic fate via JAK/STAT as well as glucocorticoid signaling. Our results suggest that the bone loss induced in cancer cachexia is associated with the depletion and the impaired differentiation capacity of the bone marrow MSCs.

The Herbal Formula CWBSD Improves Sleep Quality Dependent on Oral Microbial Type and Tongue Diagnostic Features in Insomnia.

Cheonwangbosim-dan (CWBSD) is a traditional Korean herb formula that has been widely prescribed for insomnia patients with a heart-yin deficiency (HYD) pattern. Several studies have reported that heart function and insomnia are interrelated, and few have explored associations between insomnia, oral microbiota, and tongue diagnosis. This study aimed to evaluate the effects of CWBSD on primary insomnia, tongue diagnosis, and oral microbiota. At baseline, 56 patients with primary insomnia were assigned to two groups, a HYD group and a non-HYD (NHYD) group and they took CWBSD for 6 weeks. During the study, Pittsburgh Sleep Quality Indices (PSQIs) and Insomnia Severity Indices (ISIs) decreased significantly in both groups. However, the PSQI reduction observed in the HYD group was greater than in the NHYD group and sleep times increased only in the HYD group. As sleep quality improved, the amount of tongue coating increased at the posterior tongue, where heart function appears. At baseline, the HYD and NHYD group had a specific oral microbiota (Veillonella at genus level), but no significant change was observed after taking CWBSD. Additionally, subjects were divided into two oral microbiota types ("orotypes"). The genera Prevotella, Veillonella, or Neisseria were abundant in each orotype. The reduction in PSQI in orotype 1 during the 6-week treatment period was greater than in orotype 2. In conclusion, this study shows that CWBSD could be used to treat primary insomnia in patients with a HYD pattern as determined using tongue diagnosis and oral microbiota distributional patterns.

Coordinated Regulation of Mesenchymal Stem Cell Migration by Various Chemotactic Stimuli.

Endogenous bone marrow-derived mesenchymal stem cells are mobilized to peripheral blood and injured tissues in response to changes in the expression of various growth factors and cytokines in the injured tissues, including substance P (SP), transforming growth factor-beta (TGF-ß), and stromal cell-derived factor-1 (SDF-1). SP, TGF-ß, and SDF-1 are all known to induce the migration of bone marrow-derived mesenchymal stem cells (BM-MSCs). However, it is not yet clear how these stimuli influence or interact with each other during BM-MSC mobilization. This study used mouse bone marrow-derived mesenchymal stem cell-like ST2 cells and human BM-MSCs to evaluate whether SP, TGF-ß, and SDF-1 mutually regulate their respective effects on the mobilization of BM-MSCs. SP pretreatment of ST2 and BM-MSCs impaired their response to TGF-ß while the introduction of SP receptor antagonist restored the mobilization of ST2 and BM-MSCs in response to TGF-ß. TGF-ß pretreatment did not affect the migration of ST2 and BM-MSCs in response to SP, but downregulated their migration in response to SDF-1. SP pretreatment modulated the activation of TGF-ß noncanonical pathways in ST2 cells and BM-MSCs, but not canonical pathways. These results suggest that the migration of mesenchymal stem cells is regulated by complex functional interactions between SP, TGF-ß, and SDF-1. Thus, understanding the complex functional interactions of these chemotactic stimuli would contribute to ensuring the development of safe and effective combination treatments for the mobilization of BM-MSCs.

Substance P enhances cellular migration and inhibits senescence in human dermal fibroblasts under hyperglycemic conditions.

Diabetes induces cellular dysfunction in dermal fibroblasts, such as impairment in migration, which is a major cause of chronic wound. Here, we demonstrated that the migration of human dermal fibroblasts was impaired under a high glucose culture condition. Substance P (SP) rescued the impaired migration of the fibroblasts. The activity of Rac1, Rho-associated kinase (ROCK), and Src was required for SP-mediated rescue of fibroblast migration. SP activated Rac1 and Src, whereas, NSC23766, a Rac1 inhibitor, and PP1 and PP2, Src inhibitors, inhibited SP-mediated enhancement of fibroblast migration. Y-27632, a ROCK inhibitor, inhibited the SP-mediated rescue of fibroblast migration. Senescence-associated ß-galactosidase activity increased in human dermal fibroblasts cultured in a high glucose environment, but SP inhibited the ß-galactosidase activity of the fibroblasts. These results suggest that SP promotes the migration of human dermal fibroblasts in diabetic-condition-mimicking cultures via the activity of Rac1, ROCK, and Src, and inhibits fibroblast senescence in hyperglycemic cultures.

Comparing Verum and Sham Acupuncture in Fibromyalgia Syndrome: A Systematic Review and Meta-Analysis.

OBJECTIVES: Acupuncture is often used for relieving symptoms of fibromyalgia syndrome (FMS). Our aim is to ascertain whether verum acupuncture is more effective than sham acupuncture in FMS. METHODS: We collected RCTs to investigate the effects of verum acupuncture and sham acupuncture on pain, sleep quality, fatigue, and general status in FMS patients. The databases used for data retrieval were PubMed, Central Cochrane, EMBASE, PsycINFO, CNKI, VIP, OASIS, KoreaMed, and RISS. Selection/exclusion from the retrieved records was performed according to prespecified criteria, and the final selected records were assessed according to the Cochrane risk of bias tool. The results of the included trials were synthesized on the basis of outcomes, and subgroup analysis depended on the type of add-on sham acupuncture that was performed. RESULTS: Ten RCTs (690 participants) were eligible, and eight RCTs were eventually included in the meta-analysis. The synthesis showed a sizable effect of verum acupuncture compared with sham acupuncture on pain relief (standardized mean difference (SMD) -0.49, Z = 3.26, P=0.001; I 2 = 59%), improving sleep quality (SMD -0.46, Z = 3.24, P=0.001; I 2 = 0%), and reforming general status (SMD -0.69, Z = 6.27, P < 0.00001; I 2 = 4%). However, efficacy on fatigue was insignificant (SMD -0.10, Z = 0.51, P=0.61; I 2 = 46%). When compared with a combination of simulation and improper location of needling, the effect of verum acupuncture for pain relief was the most obvious. CONCLUSIONS: Verum acupuncture is more effective than sham acupuncture for pain relief, improving sleep quality, and reforming general status in FMS posttreatment. However, evidence that it reduces fatigue was not found.

BMP-4 enhances epithelial mesenchymal transition and cancer stem cell properties of breast cancer cells via Notch signaling.

Bone morphogenetic protein (BMP) signaling and Notch signaling play important roles in tumorigenesis in various organs and tissues, including the breast. BMP-4 enhanced epithelial mesenchymal transition (EMT) and stem cell properties in both mammary epithelial cell line and breast carcinoma cell line. BMP-4 increased the expression of EMT biomarkers, such as fibronectin, laminin, N-cadherin, and Slug. BMP-4 also activated Notch signaling in these cells and increased the sphere forming efficiency of the non-transformed mammary epithelial cell line MCF-10A. In addition, BMP-4 upregulated the sphere forming efficiency, colony formation efficiency, and the expression of cancer stem cell markers, such as Nanog and CD44, in the breast carcinoma cell line MDA-MB-231. Inhibition of Notch signaling downregulated EMT and stem cell properties induced by BMP-4. Down-regulation of Smad4 using siRNA impaired the BMP-4-induced activation of Notch signaling, as well as the BMP-4-mediated EMT. These results suggest that EMT and stem cell properties are increased in mammary epithelial cells and breast cancer cells through the activation of Notch signaling in a Smad4-dependent manner in response to BMP-4.

Association between tongue coating thickness and ultraviolet fluorescence in patients with functional dyspepsia: A prospective observational study.

The aim of this study was to examine the correlation between the tongue coating thickness (TCT) and ultraviolet (UV) fluorescence and propose a new method for the estimation of TCT using a computerized tongue image acquisition system (CTIS).In this prospective and observational single-center study, we acquired tongue images under visible light and near-UV light for 60 patients with functional dyspepsia. Tongue images were acquired twice within a 30-minute interval to assess the reliability of CTIS. Then, the tongue coating was scraped and weighed to derive the wet weight of the tongue coating (WWTC). The percentage of the tongue coating area was calculated from the tongue images acquired under visible light. Mean color values (mCVs) for the UV fluorescence of the dorsal surface of the tongue were also computed.The reliabilities of the derived mCVs and percentage of the tongue coating area were acceptable (intraclass correlation coefficients, 0.907-0.947). The mCVs were more strongly correlated with WWTC than with the area, with mCV of modified lightness showing the strongest association (r = 0.785, P < .01). Finally, we suggested an estimation model for TCT based on the results.The results of this study suggest that both UV fluorescence of the dorsal tongue and the distribution area of tongue coating are useful parameters for the quantitative assessment of tongue coating. We believe that these findings will contribute to the development of a clinically useful CTIS.

Reliability, Accuracy, and Use Frequency of Evaluation Methods for Amount of Tongue Coating.

OBJECTIVE: To classify the evaluation methods for amount of tongue coating (TC) and investigate their reliability, accuracy, and frequency of use. METHODS: Articles published from 1985 to 2015 were searched for evaluation methods for the amount of TC in PubMed and the Cochrane Library. Only clinical researches were included except protocol articles. The methods were classified according to their characteristics. RESULTS: Finally, 113 articles were selected. The evaluation method for the amount of TC from the articles was classified into 4 types: intuitive, specificative, computerized, and weighing TC. The reliability in the intuitive and specificative methods (κ =0.33-0.92) showed varying levels among the studies. In general, the amount of TC calculated by the specificative method (Spearman's r=0.68-0.80) was more strongly related to the directly measured value than to the value estimated by the computerized method (Pearson's r=0.442). The number of articles published on this topic has increased consistently, and the specificative method was the most frequently used. Despite the higher reliability of the computerized method, it has not been widely used. CONCLUSIONS: The high prevalence of the specificative method would continue in clinical practice because of its convenience and accuracy. However, to establish higher reliability, the limitation of the subjectivity of the assessors should be overcome through calibration training. In the computerized method, novel algorithms are needed to obtain a higher accuracy so that it can help the practitioners confidently estimate the amount of TC.

Comparative Analysis of Tongue Indices between Patients with and without a Self-Reported Yin Deficiency: A Cross-Sectional Study.

We investigated the hypothesis that Yin-deficient patients have a reddened tongue with less coating. We screened 189 participants aged 20 to 49 years, complaining of headache. To classify patients in terms of Yin deficiency, we used two self-reporting Yin-deficiency questionnaires (Yin-Deficiency Questionnaire and Yin-Deficiency Scale) and diagnosis by a doctor. Based on the tests, a total of 33 subjects were assigned to a Yin-deficient group and 33 subjects were assigned to a nondeficient control group. Tongue images were acquired using a computerized tongue diagnostic system, for evaluating tongue indices. The tongue coating percentage and tongue redness were calculated as the mean a⁎ value of both the whole tongue area (WT a⁎) and the tongue body area (TB a⁎). The tongue coating percentage of the Yin-deficient group (34.79 ± 10.76) was lower than that of the nondeficient group (44.13 ± 14.08). The WT a⁎ value of the Yin-deficient group (19.39 ± 1.52) was significantly higher than that of the nondeficient group (18.21 ± 2.06). However, the difference in the TB a⁎ value between the two groups was not significant. In conclusion, we verified that Yin-deficient patients had less tongue coating and tended to have a more reddish tongue than nondeficient patients.

Tongue diagnosis system for quantitative assessment of tongue coating in patients with functional dyspepsia: a clinical trial.

ETHNOPHARMACOLOGICAL RELEVANCE: Tongue diagnosis is a significant procedure to examine the physiological and pathological changes of the human body in oriental medicine. However, the conventional method of tongue diagnosis including direct observation of tongue has limitations because of various external factors and subjective factors. Therefore, the current study investigated the usefulness of the tongue diagnosis system (TDS) as a diagnostic tool for evaluating tongue coating thickness (TCT) by assessing the agreement between the TDS and a gold standard established by assessors using the conventional method. MATERIALS AND METHODS: The present study was designed as a prospective clinical trial including 60 patients with functional dyspepsia. The TDS was used to capture tongue images twice within a 30-min interval to assess its reproducibility. Tongue coating percentage was measured by the TDS, and TCT was classified as either no coating, thin coating, or thick coating according to the existing diagnostic criteria. After both TDS examinations, the weight of tongue coating was quantitatively measured, and the correlation between the actual quantity of tongue coating and the percentage of the coating measured by the TDS was analyzed using Pearson׳s correlation. After collecting tongue images in all 60 patients, tongue coating was evaluated using a conventional method by 5 well-trained assessors to establish the gold standard for evaluating TCT, which allowed us to assess the diagnostic agreement between the TDS and the gold standard. After 2 weeks, TCT evaluation was repeated by the same assessors using the same images but in a random order. RESULTS: The agreement between the TDS and the gold standard for evaluating TCT was almost perfect (weighted kappa, 0.840), as was the reproducibility of the TDS (weighted kappa, 0.851). The percentage of tongue coating measured by the TDS was significantly correlated with the weight of tongue coating (r=0.442, p <0.001). The levels of intra-rater reliability ranged from substantial to almost perfect (range of weighted kappa, 0.777-0.923). The inter-rater reliability of 5 assessors was moderate (weighted kappa, 0.563). CONCLUSIONS: The present study demonstrated that the TDS can be used as a diagnostic tool for the objective and standardized evaluation of TCT in actual clinical practice.

Acupuncture with non-steroidal anti-inflammatory drugs (NSAIDs) versus acupuncture or NSAIDs alone for the treatment of chronic neck pain: an assessor-blinded randomised controlled pilot study.

OBJECTIVE: To investigate the feasibility and sample size required for a full-scale randomised controlled trial of the effectiveness of acupuncture with non-steroidal anti-inflammatory drugs (NSAIDs) for chronic neck pain compared with acupuncture or NSAID treatment alone. METHODS: A total of 45 patients with chronic neck pain participated in the study. For 3 weeks the acupuncture with NSAIDs treatment group took NSAIDs (zaltoprofen, 80 mg) daily while receiving acupuncture treatment three times a week. The acupuncture treatment group received treatment three times a week and the NSAID treatment group took NSAIDs daily. The primary outcomes were to determine the feasibility and to calculate the sample size. As secondary outcomes, pain intensity and pain-related symptoms for chronic neck pain were measured. RESULTS: With regard to enrolment and dropout rates, 88.2% of patients consented to be recruited to the trial and 15.6% of participants were lost to follow-up. The sample size for a full-scale trial was estimated to be 120 patients. Although preliminary, there was a significant change in the visual analogue scale (VAS) for neck pain intensity between the baseline measurement and each point of assessment in all groups. However, there was no difference in VAS scores between the three groups. CONCLUSIONS: This pilot study has provided the feasibility and sample size for a full-scale trial of acupuncture with NSAIDs for chronic neck pain compared with acupuncture or NSAID treatment alone. Further research is needed to validate the effects of acupuncture with NSAIDs.

Availability of tongue diagnosis system for assessing tongue coating thickness in patients with functional dyspepsia.

Tongue diagnosis is an important procedure in traditional Korean medicine (TKM). In particular, tongue coating thickness (TCT) is deemed to show the progression of the disease. However, conventional tongue diagnosis has limitations because of various external factors. Therefore, it is necessary to investigate the availability of tongue diagnosis system (TDS) in the assessment of TCT. This study has been designed as a prospective clinical trial involving 60 patients with functional dyspepsia. Tongue images will be obtained by TDS twice with a 30 min interval. The system will measure the percentage of TCT and classify it as either no coating, thin coating, or thick coating according to the existing diagnostic criteria. After finishing the collection of 60 patients' tongue images, TCT on the images will be simultaneously evaluated by the conventional method to establish the gold standard for assessing TCT by 5 well-trained clinicians. The evaluation will be repeated by the same clinicians after 2 weeks, but the order of the images will be changed. This trial is expected to provide clinical evidence for the availability of TDS as a diagnostic tool and to contribute to the standardization of the diagnosis system used in TKM. This trial is registered with ClinicalTrials.gov NCT01864837.

Low-frequency, Repetitive Transcranial Magnetic Stimulation for the Treatment of Patients with Posttraumatic Stress Disorder: a Double-blind, Sham-controlled Study.

OBJECTIVE: Several studies have suggested that repetitive transcranial magnetic stimulation (rTMS) of the right prefrontal cortex may be useful in the treatment of posttraumatic stress disorder (PTSD). The aim of this study was to compare the effect of rTMS on the right prefrontal cortex with that of sham stimulation among patients with PTSD. METHODS: In total, 18 patients with PTSD were randomly assigned to the 1-Hz low-frequency rTMS group or the sham group for 3 weeks. Primary efficacy measures were the Clinician-Administered PTSD Scale (CAPS) and its subscales, assessed at baseline and at 2, 4, and 8 weeks. RESULTS: All CAPS scores improved significantly over the study period. We found significant differences in the re-experiencing scores (F=7.47, p=0.004) and total scores (F=6.45, p=0.008) on the CAPS. The CAPS avoidance scores showed a trend toward significance (F=2.74, p=0.055), but no significant differences in the CAPS hyperarousal scores were observed. CONCLUSION: The present study showed low-frequency rTMS to be an effective and tolerable option for the treatment of PTSD. Trials using variable indices of rTMS to the right prefrontal cortex and explorations of the differences in the effects on specific symptom clusters may be promising avenues of research regarding the use of rTMS for PTSD.

Measurement of spatial pulse wave velocity by using a clip-type pulsimeter equipped with a Hall sensor and photoplethysmography.

A prototype of a clip-type pulsimeter equipped with a magnetic field-sensing semiconductor Hall sensor was developed. It has a permanent magnet attached in the "Chwan" position to the center of a radial artery. The clip-type pulsimeter is composed of a hardware system measuring voltage signals. To measure spatial pulse wave velocity (SPWV), the signal from the radial artery pulsimeter and that from the photoplethysmography (PPG) were simultaneously compared. The pulse wave data from a clinical test of 39 clinical participants (male:female = 25:14) with a mean age of 24.36 (±2.35) years was analyzed. The mean SPWV, which was simultaneously measured from the radial artery pulsimeter and PPG, was 0.8 m/s. We suggest the SPWV results were higher for men than women, because of the better vascularity of terminal tissue in men. The findings of this research may be useful for developing a biomedical signal storage device for a U-health-care system.

Association of toll-like receptor 5 gene polymorphism with susceptibility to ossification of the posterior longitudinal ligament of the spine in korean population.

OBJECTIVE: Ossification of the posterior longitudinal ligament (OPLL) has a strong genetic component. Specific gene polymorphisms may be associated with OPLL in several genes which regulate calcification in chondrocytes, change of extracellular collagen matrix and secretions of many growth factors and cytokines controlling bone morphogenesis. Toll-like receptor 5 (TLR5) may play a role in the pathogenesis of OPLL by intermediate nuclear factor-kappa B (NF-κB). The current study focused on coding single nucleotide polymorphisms (SNPs) of TLR5 for a case-control study investigating the relationship between TLR5 and OPLL in a Korean population. METHODS: A total of 166 patients with OPLL and 231 controls were recruited for a case-control association study investigating the relationship between SNPs of TLR5 gene and OPLL. Four SNPs were genotyped by direct sequencing (rs5744168, rs5744169, rs2072493, and rs5744174). SNP data were analyzed using the SNPStats, SNPAnalyzer, Haploview, and Helixtree programs. Multiple logistic regression analysis with adjustment for age and gender was performed to calculate an odds ratio (OR). RESULTS: None of SNPs were associated with OPLL in three alternative models (codominant, dominant, and recessive models; p > 0.05). A strong linkage disequilibrium block, including all 4 SNPs, was constructed using the Gabriel method. No haplotype was significantly associated with OPLL in three alternative models. CONCLUSION: These results suggest that Toll-like receptor 5 gene may not be associated with ossification of the posterior longitudinal ligament risk in Korean population.