Association between muscle quality and nutritional status among community-dwelling older adults: A cross-sectional study.

Background: Decline in muscle quality is associated with poorer health in community-dwelling older adults. Although there is evidence that malnutrition is associated with the decline of muscle quality in older adults, few analyses have considered important factors related to muscle quality. Aim: The purpose of this study was to determine the relationship between muscle quality and nutritional status in community-dwelling older adults, taking into account muscle mass, muscle strength, and amount of physical activity. Methods: This was a cross-sectional study. Data were obtained from a health checkup program in Japan. Participants were older adults aged ≥65 years living in the community who participated in the health checkup program. The data collected were echo intensity, scores on the Global Leadership Initiative on Malnutrition criteria, skeletal muscle mass, grip strength, physical activity level, and demographic data. Multiple regression analysis was used to examine the association between muscle quality and nutritional status. Results: Data were analyzed for 50 participants (mean age 77.62 years, standard deviation 6.16 years, 78.0% women). Multiple regression analysis showed that nutritional status affected muscle quality even when various factors were taken into account (B = 6.95, ß = 0.31, p = 0.04, 95% confidence interval: 0.01-0.62). Conclusion: The observed association suggests that providing nutritional support for older adults living in the community may be a useful strategy to maintain muscle quality.

Effect of digital game intervention on cognitive functions in older adults: a multiple baseline single case experimental design study.

BACKGROUND: Residents in nursing homes are prone to cognitive decline affecting memory, visuospatial cognition, and executive functions. Cognitive decline can lead to dementia, necessitating prioritized intervention. METHODS: The current study aimed to investigate whether an intervention using a digital game was effective for preserving and improving the cognitive function of residents in nursing homes. An intervention study was conducted using a single-case AB design with multiple baselines. The participants in the study were five older adults aged 65 and over who do not play digital games regularly. The study ran for 15 weeks, including a baseline (phase A) and an intervention phase (phase B). Phase A had five baselines (5 to 9 weeks) with random participant assignment. In phase B, participants engaged in a digital game (Space Invaders) individually. Cognitive function was assessed as the outcome, measured using the Brain Assessment (performed on a tablet through the Internet) at 16 measurement points. Four of five participants (two female and two male) were included in the analysis, using visual inspection and Bayesian statistics with multi-level modeling. RESULTS: Visual inspection of the graphs revealed cognitive function score improvements after the intervention for most layers in terms of memory of numbers, memory of words, mental rotation test (visuospatial ability), and total scores in the Brain Assessment. These effects were also significant in the analysis by multi-level modeling. CONCLUSIONS: The results suggest that the use of digital games may be effective for preserving and improving cognitive function among residents of nursing home. TRIAL REGISTRATION: This study was registered in the University Hospital Medical Information Network Clinical Trials Registry (UMIN000048677; public title: Effect of a Digital Game Intervention for Cognitive Functions in Older People; registration date: August 30, 2022).

Associations Between Cognitive Function and Muscle Quality Among Community-Dwelling Older Adults: A Cross-Sectional Study.

OBJECTIVE: To investigate whether muscle quality is related to cognitive function in older adults living in the community. METHODS: The participants were 40 community-dwelling older adults without a diagnosis of dementia (mean age, 78.85 ± 6.40 years; 31 women). The dependent variable was the score on the mild cognitive impairment (MCI) index of the Japanese version of the Neurobehavioral Cognitive Status Examination Five (range: 0-6; higher scores indicate MCI or possible dementia). RESULTS: Multiple regression with Bayesian statistics was performed for analysis of muscle quality, as indicated by echo intensity (EI), with skeletal muscle mass index, gait speed, physical activity level, age, and sex as covariates. EI was significantly associated with the MCI index (expected a posterior = 0.04 [95% Bayesian confidence interval: 0.01, 0.07], t = 2.47, ß = 0.41, p = 0.019). CONCLUSIONS: The results suggest that EI may be related to the cognitive function of older adults living in the community. Future studies should examine whether focusing on EI can help prevent cognitive decline among older adults..

Relationship between Phase Angle and Physical Activity Intensity among Community-Dwelling Older Adults in Japan: A Cross-Sectional Study.

This cross-sectional study aimed to determine the association between phase angle (PhA) and physical activity intensity in community-dwelling older Japanese adults. The intensity and time of physical activity for predicting high PhA were also examined. This study involved 67 community-dwelling older adults (mean age: 78.3 ± 5.5; female: 83.6%). We measured the physical activity and body composition of the participants. Physical activity was measured using a triaxial accelerometer, and light-intensity physical activity (LPA) and moderate-to-vigorous intensity physical activity (MVPA) hours per day were calculated from the results. Body composition was measured using Inbody S10, and the PhA was calculated from the measurements of the right side of the body. Bayesian statistical modeling revealed an association between PhA and MVPA (ß = 0.256; p = 0.022; 95% Bayesian confidence interval [CI] = 0.001, 0.012), but not LPA (ß = -0.113; p = 0.341; 95% Bayesian CI = -0.002, 0.001), even after adjustment for confounders. The cutoff value of MVPA predicting high PhA, calculated by the receiver operator characteristic curve, was 19.7 min/d (sensitivity = 0.906; specificity = 0.429). These results can be used to develop strategies to increase PhA in older adults and suggest that MVPA is important in this population.

A case of recurrent chronic eosinophilic pneumonia after switching from benralizumab to dupilumab.

Dupilumab inhibits interleukin-4Rα and suppresses type 2 inflammation. Careful administration of dupilumab is required because it increases the blood eosinophil count secondary to a decrease in local eosinophil counts, sometimes resulting in eosinophilic complications. We herein report a case of recurrent chronic eosinophilic pneumonia after switching from benralizumab to dupilumab. A 54-year-old man with a history of eosinophilic pneumonia presented to our hospital with symptoms of cough, fever, and phlegm production six months after beginning dupilumab administration for recurrent chronic rhinosinusitis. When using dupilumab, it is essential to carefully monitor patients' eosinophil trends and pulmonary symptoms.

Appetite and family and friends network among community-dwelling older adults: A cross-sectional study.

OBJECTIVES: The aim of this study was to investigate the stronger correlate of appetite-family or friend networks-in community-dwelling older adults, given that undernutrition can impair physical function, increase mortality, and be influenced by social networks. METHODS: A cross-sectional study was conducted in Kasugai City, Aichi Prefecture, and Nara City, Nara Prefecture, Japan, between August 2019 and March 2023. The analysis included 119 participants (women: 79%, mean age: 76.5 ± 5.6 y). A multiple regression analysis was performed, using the scores from the Japanese version of the Simplified Nutritional Appetite Questionnaire (SNAQ-J) as the dependent variable and family network and friend network as the independent variables. The analysis included social participation, living alone status, sex, age, body mass index, skeletal muscle mass index, grip strength, walking speed, and the Japanese version of the 15 Geriatric Depression Scale score as covariates to examine their relationship with appetite. RESULTS: The mean value of the SNAQ-J score of the participants was 15.4 ± 1.2. Seven participants (6%) had a loss of appetite. Family network was significantly associated with appetite (B = 0.121, ß = 0.266, P <0.05; 95% condidence interval [CI], 0.030-0.212). In the single regression analysis, the friend network was significantly associated with the total score of the SNAQ-J (B = 0.115, P <0.001; 95% CI, 0.052-0.177); however, this association was not observed in the multiple regression analysis (B = 0.002, ß = 0.006, P = 0.954; 95% CI, -0.074-0.078). CONCLUSION: Appetite was associated with family networks. Among social networks, focusing on family networks may help prevent the loss of appetite in older adults in Japan.

Clinical characteristics in Japanese patients with chronic rhinosinusitis who underwent endoscopic sinus surgery.

OBJECTIVE: There is heterogeneity in the pathophysiology of chronic rhinosinusitis (CRS). Obtaining a detailed understanding of patient profiles in specific regions can provide valuable information not only for clinical practice but also future research plans. The aim of this study was to investigate the characteristics of patients who underwent endoscopic sinus surgery (ESS) for CRS. METHODS: This retrospective, single-center study examined the features of 453 patients with CRS who underwent ESS in the Tokyo area of Japan. The study evaluated various factors in patients with CRS including sex and age, the Japanese Epidemiological Survey of Refractory Eosinophilic Chronic Rhinosinusitis (JESREC) score, the recurrence rate of CRS, comorbidities of asthma and/or allergic diseases, and IgE sensitization to 12 inhaled allergens. RESULTS: Age-related declines in the sensitization rate to inhaled allergens were observed, and the most notable age-related decrease in specific IgE antibodies was observed for house dust mites (HDM) (p = 8.3 × 10-7). Sensitization to HDM, cat dander, and various types of fungi, including Aspergillus, was frequently observed in the CRS with asthma group, with rates of 54%, 17%, and 17%, respectively. We found that 23% of the patients had recurrence. In the recurrence group, the positive rates of specific IgE antibodies for birch and cat dander were significantly higher than in the no recurrence group. Bronchial asthma was identified as an important factor for recurrence. Among male patients, the recurrence group was younger than the no-recurrence group (p = 0.0032). Severe eosinophilic CRS (ECRS) showed early recurrence after surgery, with over the half of the patients experiencing at least one recurrence within 2 years post-surgery. Among patients with ECRS, the recurrence rate for females was 1.92 times higher than for males. CONCLUSION: Our study revealed the influences of age and sex on various clinical phenotypes of CRS patients undergoing ESS. There was a high sensitization rate to cat dander in both the recurrence and asthma groups. Further research on diverse disease etiologies is necessary to improve therapeutic strategies for patients with CRS.

Relationships between Loneliness and Occupational Dysfunction in Community-Dwelling Older Adults: A Cross-Sectional Study.

The study explored cross-sectional associations between loneliness and occupational dysfunction in community-dwelling older adults. Seventy-four older adults (12 men and 62 women; mean age 73.9 ± 8.3 years) completed a questionnaire survey that included the Japanese version of the UCLA Loneliness Scale Version 3 and the Classification and Assessment of Occupational Dysfunction (CAOD). Bayesian statistical modeling was used for a more stable estimation given the small sample. For model selection, we assumed a univariate analysis model of the CAOD (Model 1); a multivariate analysis model, including confounding factors in Model 1 (Model 2); and a multivariate analysis model, including random effects in Model 2 (Model 3). The best model was selected by comparing the widely applicable information criterion (WAIC) and the widely applicable Bayesian information criterion (WBIC) for each model. Bayesian statistics with the dependent variable as "loneliness" showed that the best model used "occupational dysfunction" as the independent variable and included confounding factors and random effects (WAIC = 474.5 and WBIC = 213.1). The best model identified an association between occupational dysfunction and loneliness (odds ratio [OR] = 2.363; 95% Bayesian confidence interval [CI] = 1.105-5.259). This study highlights the role of occupational dysfunction in addition to the risks and related factors reported to date when dealing with loneliness. Therapists could help older adults cope with loneliness by supporting their social participation and improving their occupational dysfunction.

Dupilumab improves eosinophilic otitis media associated with eosinophilic chronic rhinosinusitis.

BACKGROUND: Eosinophilic otitis media (EOM) is a refractory condition associated with eosinophilic chronic rhinosinusitis and bronchial asthma. EOM is characterized by type-2 inflammation and is refractory to various treatments. We investigated the efficacy of dupilumab, interleukin-4 receptor alpha antagonist, for patients with EOM complicated by eosinophilic chronic rhinosinusitis (ECRS). METHODS: Between April 2017 and April 2022, we treated 124 patients with dupilumab for refractory CRS or bronchial asthma. Of these, 14 had EOM concurrently, and 10 of them who had been treated for >6 months were included in our study. We retrospectively evaluated the efficacy of dupilumab by the amount of systemic corticosteroid used, the frequency of exacerbations, severity score of EOM, computed tomography (CT) score of temporal bones, and pure tone audiometry. We also enrolled 8 EOM patients without dupilumab treatment as a control group. RESULTS: Dupilumab significantly improved the amount of systemic corticosteroid used and the frequency of exacerbation and compared with before dupilumab was used (p = 0.01 and <0.01, respectively). All patients could be weaned from systemic-corticosteroid therapy by 54 weeks of dupilumab use. The severity score of EOM and CT score for temporal bones were significantly lower than before the treatment (p = 0.01 and 0.01, respectively). Compared to the control group, the systemic corticosteroid used and severity scores were improved in the dupilumab group (p = 0.02 and < 0.01, respectively). CONCLUSIONS: Dupilumab could be used to wean patients from systemic corticosteroids with the improvement of severity score in EOM associated with ECRS and bronchial asthma.

Effect of acute high-intensity intermittent exercise on serum brain-derived neurotrophic factor concentrations.

BACKGROUND: This study aimed to examine changes in serum brain-derived neurotrophic factor (BDNF) concentrations after exhaustive high-intensity intermittent exercise (HIIE) and non-exhaustive HIIE, and to compare the two conditions. METHODS: Eight healthy male college students (age: 22±1 year) participated in exhaustive (sets: 6-7) and non-exhaustive (sets: 5) HIIE. In both conditions, participants repeated sets of 20 seconds of exercise at 170% V̇O2max with 10 seconds of rest between sets. Serum BDNF was measured 8 times in each condition: 30 minutes after resting, 10 minutes after sitting, immediately after HIIE, and 5, 10, 30, 60, and 90 minutes after main exercise. Changes in serum BDNF concentrations over time and between measurement points in both conditions were measured using a two-way repeated measures ANOVA. RESULTS: Serum BDNF concentrations were measured, revealing significant interaction between two factors (conditions and measurement points) (F=3.482, P=0.027). In the exhaustive HIIE, there were significant increases at 5 minutes (P<0.01) and 10 minutes (P<0.01) after exercise compared to after resting. In the non-exhaustive HIIE, there was a significant increase immediately after (P<0.01) and 5 minutes after (P<0.01) exercise compared to resting. Comparison of the serum BDNF concentrations at each measurement point showed a significant difference at 10 minutes after exercise, with significantly higher values for the exhaustive HIIE condition (P<0.01, r=0.60). CONCLUSIONS: Exhaustive and non-exhaustive HIIE are time-efficient exercises that increase serum BDNF concentrations in healthy adults.

Tramadol regulates the activation of human platelets via Rac but not Rho/Rho-kinase.

Tramadol is a useful analgesic which acts as a serotonin and noradrenaline reuptake inhibitor in addition to µ-opioid receptor agonist. Cytoplasmic serotonin modulates the small GTPase activity through serotonylation, which is closely related to the human platelet activation. We recently reported that the combination of subthreshold collagen and CXCL12 synergistically activates human platelets. We herein investigated the effect and the mechanism of tramadol on the synergistic effect. Tramadol attenuated the synergistically stimulated platelet aggregation (300 µM of tramadol, 64.3% decrease, p<0.05). Not morphine or reboxetine, but duloxetine, fluvoxamine and sertraline attenuated the synergistic effect of the combination on the platelet aggregation (30 µM of fluvoxamine, 67.3% decrease, p<0.05; 30 µM of sertraline, 67.8% decrease, p<0.05). The geranylgeranyltransferase inhibitor GGTI-286 attenuated the aggregation of synergistically stimulated platelet (50 µM of GGTI-286, 80.8% decrease, p<0.05), in which GTP-binding Rac was increased. The Rac1-GEF interaction inhibitor NSC23766 suppressed the platelet activation and the phosphorylation of p38 MAPK and HSP27 induced by the combination of collagen and CXCL12. Tramadol and fluvoxamine almost completely attenuated the levels of GTP-binding Rac and the phosphorylation of both p38 MAPK and HSP27 stimulated by the combination. Suppression of the platelet aggregation after the duloxetine administration was observed in 2 of 5 patients in pain clinic. These results suggest that tramadol negatively regulates the combination of subthreshold collagen and CXCL12-induced platelet activation via Rac upstream of p38 MAPK.

HSP70 inhibitors upregulate prostaglandin E1-induced synthesis of interleukin-6 in osteoblasts.

Interleukin-6 (IL-6) is a pro-inflammatory and bone-resorptive cytokine that also regulates bone formation. We previously showed that prostaglandin E1 (PGE1) induces the synthesis of IL-6 by activating p44/p42 mitogen-activated protein kinase (MAPK), stress-activated protein kinase/c-Jun N-terminal kinase (SAPK/JNK), and p38 MAPK in osteoblast-like MC3T3-E1 cells. In the present study, we investigated whether heat shock protein 70 (HSP70), a molecular chaperone that coordinates protein folding and homeostasis, affects PGE1-stimulated IL-6 synthesis in MC3T3-E1 cells through the MAPK activation. The osteoblast-like MC3T3-E1 cells were treated with HSP70 inhibitors-VER-155008 and YM-08-, PD98059, SB203580 or SP600125 and then stimulated with PGE1. IL-6 synthesis was evaluated using an IL-6 enzyme-linked immunosorbent assay kit. IL-6 mRNA expression was measured by real-time RT-PCR. The phosphorylation of p38 MAPK was evaluated by Western blotting. We found that VER-155008, an HSP70 inhibitor, enhanced the PGE1-stimulated IL-6 release and IL-6 mRNA expression. YM-08, another HSP70 inhibitor, also enhanced PGE1-stimulated IL-6 release. PD98059, a p44/p42 MAPK inhibitor, and SP600125, a SAPK/JNK inhibitor, upregulated PGE1-stimulated IL-6 release. On the other hand, SB203580, a p38 MAPK inhibitor, suppressed PGE1-stimulated IL-6 release. YM-08 stimulated the PGE1-induced phosphorylation of p38 MAPK. SB203580 suppressed the amplification by YM-08 of the PGE1-stimulated IL-6 release. Our results suggest that HSP70 inhibitors upregulate the PGE1-stimulated IL-6 synthesis through p38 MAPK in osteoblasts and therefore affect bone remodeling.

Frail Older Adults without Occupational Dysfunction Maintain Good Subjective Well-Being: A Cross-Sectional Study.

The purpose of this cross-sectional study was to clarify the relationship between frailty/occupational dysfunction (OD), both with and without, and subjective well-being among community-dwelling older adults. A total of 2308 (average age: 72.2 ± 5.1, female: 47.0%) independently living older adults in Kasama City, Japan, completed a self-administered questionnaire in November 2019. OD, frailty, and subjective well-being were assessed. Participants were classified into six groups: robust and healthy occupational function (HOF), robust and OD, pre-frail and HOF, pre-frail and OD, frail and HOF, and frail and OD. To examine the relationship between frailty/OD and subjective well-being, we performed an analysis of variance with subjective well-being as the dependent variable and with and without frailty/OD (six groups) as the independent variables. The results showed a significant association between with and without frailty/OD and subjective well-being in community-dwelling older adults. The subjective well-being of the pre-frail and HOF group was significantly better than that of the robust and OD group. Furthermore, the subjective well-being of the frail and HOF group was significantly better than that of the pre-frail and OD group. These results can be used to develop a new support method for frailty.

Amyloid ß protein negatively regulates human platelet activation induced by thrombin receptor-activating protein.

Amyloid ß protein deposition in cerebral vessels, a characteristic of Alzheimer's disease, is a risk factor for intracerebral hemorrhage. Amyloid ß protein directly modulates human platelet function; however, the exact mechanism of action is unclear. Therefore, we investigated the effects of amyloid ß protein on human platelet activation using an aggregometer with laser scattering. Amyloid ß protein decreased platelet aggregation induced by thrombin receptor-activating protein, but not by collagen and ADP. Amyloid ß protein also suppressed platelet aggregation induced by SCP0237 and A3227. Platelet-derived growth factor-AB secretion and phosphorylated-heat shock protein 27 release by thrombin receptor-activating protein were inhibited by amyloid ß protein. Additionally, thrombin receptor-activating protein-induced phosphorylation of JNK and p38 MAP kinase was reduced by amyloid ß protein. Collectively, our results strongly suggest that amyloid ß protein negatively regulates protease-activated receptor-elicited human platelet activation. These findings may indicate a cause of intracerebral hemorrhage due to amyloid ß protein.

Relationship between Empowerment and Functioning and Disability in Older Japanese Patients: A Covariance Structure Analysis.

In the present study, 151 Japanese older adults aged over 65 years and admitted to recovery-phase rehabilitation facilities were enrolled to investigate the relationship between empowerment and contextual factors, functioning and disability, with structural equation modeling (SEM). The analysis included 151 patients aged 81.75 ± 7.15 years, including 54 males (35.76%) and 97 females (64.24%). The results of the SEM analysis showed that role presence (ß = 0.45, p < 0.01) and family structure (ß = 0.18, p = 0.02) significantly impacted empowerment. In addition, the results showed that patient empowerment positively impacted physical activity (ß = 0.25, p < 0.01) and psychosomatic functions and abilities (ß = 0.36, p < 0.01). Furthermore, the goodness-of-fit of the model hypothesized in this study was shown to have explanatory power. This study showed that empowerment contributed to the prevention of physical inactivity and confinement among Japanese older patients. In other words, the study provided evidence for the importance of empowerment-based program planning in the practice of person-centered care aimed at promoting the health and discharge of older patients in Japan.

Relationship between nutritional status and phase angle as a noninvasive method to predict malnutrition by sex in older inpatients.

Phase angle has been suggested as a useful, noninvasive, and objective index to evaluate the nutritional status of older people. However, there are no studies analyzing the relationship between nutritional status and phase angle in older patients, according to sex. The aim of this study was to clarify the relationship between phase angle and malnutrition, and to calculate cut-off points of malnutrition with phase angle in older inpatients, according to sex. This study was a retrospective cross-sectional study. Participants were older inpatients of a rehabilitation unit, and data within 1 week of hospitalization were collected from the medical records. We collected data of demographics, phase angle, and the Geriatric Nutritional Risk Index. Phase angle was measured with InBody S10. To confirm whether phase angle is an important factor in predicting malnutrition, we conducted binary logistic regression analysis. In addition, to determine the cut-off points of malnutrition in older inpatients, we used the receiver operator characteristic (ROC) curve. Participants included 59 men (mean age 76.5 years) and 101 women (mean age 78.8 years). As a result of statistical analysis, phase angle was an important factor related to malnutrition in both male and female inpatients. Our findings showed that cut-off points of 4.03 degrees (sensitivity; 87.0%, specificity; 75.9%) in male patients and 3.65 degrees (sensitivity; 78.6%, specificity; 60.5%) in female patients could be used to predict malnutrition. The results of this study suggest that phase angle may be useful as an indicator to predict the nutritional status of older inpatients.

HSP90 inhibitors strengthen extracellular ATP-stimulated synthesis of interleukin-6 in osteoblasts: Amplification of p38 MAP kinase.

Heat shock protein 90 (HSP90) is expressed ubiquitously in a variety of cell types including osteoblasts. HSP90 acts as a key driver of proteostasis under pathophysiological conditions. Here, we investigated the involvement of HSP90 in extracellular ATP-stimulated interleukin (IL)-6 synthesis and HSP90 downstream signalling in osteoblast-like MC3T3-E1 cells. In osteoblasts, extracellular ATP stimulates the synthesis of IL-6, a bone-remodelling agent. Geldanamycin, 17-allylamino-17-demethoxy-geldanamycin (17-AAG) and onalespib, three different HSP90 inhibitors, amplified the ATP-stimulated IL-6 release. Geldanamycin increased IL-6 mRNA expression elicited by ATP. ATP enhanced the triiodothyronine-induced osteocalcin release, but HSP90 inhibitors suppressed the release. Extracellular ATP induced the phosphorylation of p44/p42 mitogen-activated protein kinase (MAPK), p38 MAPK, c-Jun N-terminal kinase (JNK), p70 S6 kinase, Akt, and myosin phosphatase-targeting subunit (MYPT), a Rho-kinase substrate. SB203580, an inhibitor of p38 MAPK, suppressed ATP-stimulated IL-6 release. Inhibitors of MEK1/2 (PD98059), JNK (SP600125), upstream kinase of p70 S6 kinase (rapamycin) and Akt (deguelin), all increased IL-6 release. Y27632, a Rho-kinase inhibitor, failed to affect the IL-6 release stimulated by ATP. Geldanamycin and 17-AAG both amplified ATP-induced p38 MAPK phosphorylation, although geldanamycin inhibited the phosphorylation of Akt induced by ATP. In addition, SB203580 significantly reduced the amplification by geldanamycin of the IL-6 release. Taken together, our results strongly suggest that HSP90 inhibitors up-regulate extracellular ATP-stimulated IL-6 synthesis via amplification of p38 MAPK activation in osteoblasts. SIGNIFICANCE OF THE STUDY: Heat shock protein 90 (HSP90) acts as a key driver of proteostasis under pathophysiological conditions in a variety of cell types. We have previously shown that HSP90 is expressed at high levels in osteoblast-like MC3T3-E1 cells, even in their quiescent state, consistent with HSP90 performing an important physiological function in osteoblasts. In the present study, we investigated whether HSP90 is implicated in extracellular ATP-induced interleukin (IL)-6 synthesis in osteoblast-like MC3T3-E1 cells. Our results strongly suggest that HSP90 inhibitors up-regulate extracellular ATP-stimulated IL-6 synthesis via amplification of p38 mitogen-activated protein kinase activation in osteoblasts.

Synergistic effect of collagen and CXCL12 in the low doses on human platelet activation.

CXCL12, also known as stromal cell-derived factor-1, is a chemokine classified into CXC families, which exerts its function by binding to specific receptors called CXCR4 and CXCR7. Human platelets express CXCR4 and CXCR7 on the plasma membrane. It has been reported that CXCL12 potentiates to induce platelet aggregation in cooperation with agonists including collagen. However, the precise roles and mechanisms of CXCL12 in human platelet activation are not fully elucidated. In the present study, we investigated the effect of simultaneous stimulation with low doses of collagen and CXCL12 on the activation of human platelets. The simultaneous stimulation with collagen and CXCL12 induced the secretion of platelet-derived growth factor (PDGF)-AB and the release of soluble CD40 ligand (sCD40L) from human platelets in addition to their aggregation, despite the fact that the simultaneous stimulation with thrombin receptor-activating peptide (TRAP) or adenosine diphosphate (ADP), and CXCL12 had little effects on the platelet aggregation. The agonist of Glycoprotein (GP) Ⅵ convulxin and CXCL12 also induced platelet aggregation synergistically. The monoclonal antibody against CXCR4 but not CXCR7 suppressed the platelet aggregation induced by simultaneous stimulation with collagen and CXCL12. The phosphorylation of p38 mitogen-activated protein kinase (MAPK), but not p44/p42 MAPK, was induced by the simultaneous stimulation. In addition, the simultaneous stimulation with collagen and CXCL12 induced the phosphorylation of HSP27 and the subsequent release of phosphorylated-HSP27 from human platelets. SB203580, a specific inhibitor of p38 MAPK, attenuated the platelet aggregation, the phosphorylation of p38 MAPK and HSP27, the PDGF-AB secretion, the sCD40L release and the phosphorylated-HSP27 release induced by the simultaneous stimulation with collagen and CXCL12. These results strongly suggest that collagen and CXCL12 in low doses synergistically act to induce PDGF-AB secretion, sCD40L release and phosphorylated-HSP27 release from activated human platelets via p38 MAPK activation.

Tramadol enhances PGF2α-stimulated osteoprotegerin synthesis in osteoblasts.

Osteoprotegerin (OPG) synthesized by osteoblasts is currently considered a crucial regulator to suppress the formation and function of osteoclasts. We previously showed that the synthesis of OPG is stimulated by prostaglandin F2α (PGF2α) in the involvement of p38 mitogen-activated protein kinase (MAPK), stress-activated protein kinase/c-Jun N-terminal kinase (SAPK/JNK) and p44/p42 MAPK in osteoblast-like MC3T3-E1 cells. We also found that Rho-kinase is involved in the signaling of PGF2α upstream of p38 MAPK in these cells. Tramadol is widely used to treat chronic pain, such as low back pain associated with osteoporosis. We investigated whether or not tramadol affects the OPG release induced by PGF2α in osteoblast-like MC3T3-E1 cells. The levels of OPG in the conditioned medium were measured by an enzyme-linked immunosorbent assay. The mRNA expression of OPG was determined with real-time reverse transcription polymerase chain reaction. The phosphorylation of target protein was determined with a Western blot analysis. PGF2α induced the release and the mRNA expression of OPG, which tramadol significantly enhanced. Morphine, a selective µ-opioid receptor (MOR) agonist, also enhanced the PGF2α-induced OPG release. In addition, naloxone, a MOR antagonist, suppressed the enhancement by tramadol or morphine of the PGF2α-induced OPG synthesis. Tramadol upregulated the phosphorylation of SAPK/JNK and p38 MAPK stimulated by PGF2α but not that of p44/p42 MAPK or myosin phosphatase targeting protein (MYPT), a substrate of Rho-kinase. The inhibitors of both p38 MAPK and SAPK/JNK, SB203580 and SP600125, respectively, reduced the tramadol amplification of OPG release stimulated by PGF2α. The present results strongly suggest that tramadol enhances the synthesis of OPG stimulated by PGF2α through MOR in osteoblasts, and that the amplifying effect is exerted at upstream of p38 MAPK and SAPK/JNK but downstream of Rho-kinase.

Olive polyphenol reduces the collagen-elicited release of phosphorylated HSP27 from human platelets.

Hydroxytyrosol (HT) and oleuropein (OLE) are natural polyphenols found in extra virgin olive oil. Accumulating evidence indicates that ingestion of olive oil contributes to reduce the risk of cardiovascular diseases and stroke. It has been reported that HT and OLE inhibit human platelet aggregation. We have shown that collagen induces the phosphorylation of heat shock protein 27 (HSP27) in human platelets, resulting in the release of HSP27, an extracellular pro-inflammatory agent. In this study, we investigated the effects of HT and OLE on the collagen-stimulated human platelet activation. The PDGF-AB secretion and the soluble CD40 ligand (sCD40L) release by collagen were reduced by HT or OLE. HT and OLE significantly suppressed the phosphorylation of HSP27 and the release of phosphorylated-HSP27. These findings suggest that olive polyphenol reduces the collagen-stimulated phosphorylation of HSP27 in human platelets and the release. Our results may provide a novel anti- inflammatory effect of olive polyphenol.