Patient with suspected co-infection of hemorrhagic fever with renal syndrome and malaria: a case report.

Background: Hemorrhagic fever with renal syndrome (HFRS) is a natural epidemic disease that can be caused by the Hantaan virus (HTNV). Malaria is caused by plasmodium and can be transmitted by a mosquito bite. The similar manifestations shared by these disorders pose a challenge for clinicians in differential diagnosis, in particular, coupled with a false-positive serological test. Case presentation: A 46-year-old man was admitted for fever and chills for over 10 days and was suspected of being co-infected with HFRS and malaria due to a history of travel to malaria-endemic areas and a positive HTNV-immunoglobulin M (IgM) test. Although leukocytosis, thrombocytopenia, renal injury, lymphocytosis, overexpression of interleukin-6, and procalcitonin were observed during the hospitalization, the hypotensive, oliguria, and polyuria phases of the HFRS course were not observed. Instead, typical symptoms of malaria were found, including a progressive decrease in erythrocytes and hemoglobin levels with signs of anemia. Furthermore, because the patient had no history of exposure to HFRS endemic areas, exposure to an HTNV-infected rodent, or a positive HTNV-IgG test, and false serological tests of IgM can be caused by various factors, the HFRS coinfection with malaria was ruled out. Conclusion: Misdiagnosis can be easily induced by a false serological test, in particular the IgM test which can be influenced by various factors. A combination of health history, epidemiology, physical examination, precise application of specific examinations involving tests of conventional laboratory parameters as well as well-accepted methods such as the immunochromatographic (ICG) test, real-time reverse transcription-polymerase chain reaction (PCR), and Western blot (WB), and acquaintance with disorders with similar manifestations will contribute to the precise diagnosis in clinical treatment.

Non­contact locking plate: A useful alternative to external fixation in second­stage treatment of post­traumatic tibial osteomyelitis.

The treatment of infected tibial bone defects can be challenging for the orthopedic surgeon. Therefore, the aim of the present study was to compare the fixation endurance, bone union time, lower limb joint function and complications associated with different fixation methods in the treatment of bone defects caused by debridement in the treatment of post-traumatic osteomyelitis. The clinical data of 55 patients with infected bone defects of the lower extremities following traumatic injury, who had undergone radical debridement between January 2017 and September 2020, were retrospectively analyzed. The patients were divided into three groups according to the type of fixation during reconstruction, namely the external fixation (EX), internal fixation (IX) and non-contact locking plate (LP) groups. The demographic data, time to bone union, bacterial culture results, complications and Self-Rating Anxiety Scale (SAS) scores of the patients were compared among the three groups. The results indicated that the differences in time to bone union and recurrence rates of osteomyelitis among the three groups were not statistically significant. By contrast, functional status after surgery was significantly higher in the LP group compared with the EX group. In total, 8/22 patients (36.4%) in the EX group, 4/13 patients (30.8%) in the IX group and 4/20 patients (20.0%) in the non-contact LP group had shortened limbs and deformed tibia. The SAS assessment results revealed that patients in the non-contact LP group had the lowest rates of moderate and severe anxiety. In conclusion, the results of the present study demonstrate that the non-contact locking plate technique provided stable fixation without any contact between the implant and bone tissues. Therefore, this technique may be viable for use during the reconstruction stage of post-traumatic tibial osteomyelitis.

Characteristics of the Hantaan virus complicated with SARS-CoV2 infection: A case series report.

Background: Coinfection poses a persistent threat to global public health due to its severe effect on individual-level infection risk and disease outcome. Coinfection of SARS-CoV2 with one or more pathogens has been documented. Nevertheless, this virus co-infected with the Hantaan virus (HTNV) is rarely reported. Case summary: Here, we presented three cases of HTNV complicated with SARS-CoV2 infection. Not only the conditions including general clinical manifestations, immune and inflammation parameters fluctuation presented in the single infection of HTNV or SARS-CoV2 can be found, but also the unexpected manifestations have attracted our attention that presented as more symptoms of HTNV infection including exudative changes in both lungs and an amount of bilateral pleural effusion as well as bilateral kidney enlargement rather than typical viral pneumonia in SARS-CoV2 infection. Fortunately, the conditions of patients gradually return to normal which is beneficial from the antiviral treatment, hemodialysis, and various supportive therapies including anti-inflammation, liver and gastric mucosa protection. Conclusion: Unexpected manifestations of coinfection patients present herein may be associated with multiple factors including virus load, competition or antagonism among antigens, and the susceptibility of target cells to the various pathogens, even though the pathogenesis of HTNV and SARS-CoV2 remains to be elucidated. Given that these two viruses have posed a profound influence on the socioeconomic, healthcare system worldwide, and the threat of coinfection to public health, it is warranted for clinicians, public health authorities, and infectious disease researchers to have a high index of consideration for patients co-infected with HTNV and SARS-CoV2.

The Effect of CT Imaging Technology in the Diagnosis of Thoracic and Cardiac Surgery Diseases.

In order to increase doctors' cognition of the three-dimensional anatomical structure of cardiothoracic and cardiothoracic surgery and increase the diagnosis rate and cure rate of cardiothoracic surgery diseases, the authors propose a method of CT imaging technology for diagnosing cardiothoracic surgery diseases. Through the joint Hookwire positioning of 3D-CTBA, application in thoracoscopic segmentectomy and CT energy spectrum curve, retrospective analysis of diagnosis of intrathoracic lymph node metastasis in non-small-cell lung cancer, 3D-CTBA and CT-guided Hookwire localization, and preoperative CT-enhanced scanning were performed using two methods. The experimental results showed that the chest tube placement time, postoperative thoracic drainage volume, and postoperative hospital stay after the first operation all showed a good trend. The diagnostic sensitivity was 87.1%. The specificity was 92.6%. The correct index was 79.7%. The accuracy was 91.3%. The positive predictive value was 79.4%. And the negative predictive value was 95.7%. These data prove that CT imaging technology has high diagnostic value for thoracic and cardiac surgery diseases and can effectively help the formulation and implementation of thoracic and cardiac surgery diseases.

Effects of Ulinastatin on Myocardial Ischemia-Reperfusion Injury, Cardiac Function, and Serum TNF-α and IL-10 Levels in Patients Undergoing Cardiac Valve Replacement under Cardiopulmonary Bypass.

Background: Myocardial ischemia-reperfusion injury (MIRI) is a very common adverse reaction after cardiac valve replacement (CVR) under cardiopulmonary bypass, which seriously affects the rehabilitation and prognosis of patients. Objective: The prevention and treatment of MIRI are a hotspot of modern medical research, and this study is aimed at providing reliable reference and guidance for future clinical prevention and treatment of MIRI by analyzing the effects of ulinastatin (UL) on cardiac function and MIRI of patients after CVR. Methods: A total of 104 patients undergoing CVR under cardiopulmonary bypass in our hospital were selected as research participants. Among them, 52 patients treated with UL were assigned to the observation group, and the rest 52 patients given the same amount of normal saline were assigned to the control group. The cardiopulmonary bypass status, postoperative status, cardiac function, inflammatory response, oxidative stress response, and hemodynamics were observed and compared between the two groups. In addition, clinical efficacy and safety and patient prognosis were compared. Results: Through experimental analysis, we found that UL had no significant effect on the clinical efficacy, safety, and prognosis of patients after surgery (P > 0.05) but had obvious protective effects on cardiopulmonary bypass status, cardiac function, inflammation, oxidative stress, and hemodynamics (P < 0.05). Conclusion: UL can effectively prevent the occurrence of MIRI after CVR under cardiopulmonary bypass, which is worthy of clinical application.

In-Depth Sulfhydryl-Modified Cellulose Fibers for Efficient and Rapid Adsorption of Cr(VI).

As one of the hazardous heavy metal ion pollutants, Cr(VI) has attracted much attention in the sewage treatment research field due to its wide distribution range and serious toxicity. In this paper, cellulose fibers were prepared by wet spinning and followed by freeze drying, resulting in large porosity. Subsequently, in-depth sulfhydryl modification was applied with cellulose fibers for efficient and rapid adsorption of Cr(VI). The maximum adsorption capacity of sulfhydryl-modified cellulose fibers to Cr(VI) can reach 120.60 mg g-1, the adsorption equilibrium can be achieved within 300 s, and its adsorption rate can reach 0.319 mg g-1 s-1. The results show that the in-depth sulfhydryl-modified cellulose fibers perform excellent adsorption capacity for chromium, and are also available for other heavy metal ions. At the same time, the low cost and environmentally friendly property of the as-synthesized material also demonstrate its potential for practical usage for the treatment of heavy metal ion pollution in waste water.

HTO/Cellulose Aerogel for Rapid and Highly Selective Li+ Recovery from Seawater.

To achieve rapid and highly efficient recovery of Li+ from seawater, a series of H2TiO3/cellulose aerogels (HTO/CA) with a porous network were prepared by a simple and effective method. The as-prepared HTO/CA were characterized and their Li+ adsorption performance was evaluated. The obtained results revealed that the maximum capacity of HTO/CA to adsorb Li+ was 28.58 ± 0.71 mg g-1. The dynamic k2 value indicated that the Li+ adsorption rate of HTO/CA was nearly five times that of HTO powder. Furthermore, the aerogel retained extremely high Li+ selectivity compared with Mg2+, Ca2+, K+, and Na+. After regeneration for five cycles, the HTO/CA retained a Li+ adsorption capacity of 22.95 mg g-1. Moreover, the HTO/CA showed an excellent adsorption efficiency of 69.93% ± 0.04% and high selectivity to Li+ in actual seawater. These findings confirm its potential as an adsorbent for recovering Li+ from seawater.

Frontline Science: COVID-19 infection induces readily detectable morphologic and inflammation-related phenotypic changes in peripheral blood monocytes.

Excessive monocyte/macrophage activation with the development of a cytokine storm and subsequent acute lung injury, leading to acute respiratory distress syndrome (ARDS), is a feared consequence of infection with COVID-19. The ability to recognize and potentially intervene early in those patients at greatest risk of developing this complication could be of great clinical utility. In this study, we performed flow cytometric analysis of peripheral blood samples from 34 COVID-19 patients in early 2020 in an attempt to identify factors that could help predict the severity of disease and patient outcome. Although we did not detect significant differences in the number of monocytes between patients with COVID-19 and normal healthy individuals, we did identify significant morphologic and functional differences, which are more pronounced in patients requiring prolonged hospitalization and intensive care unit (ICU) admission. Patients with COVID-19 have larger than normal monocytes, easily identified on forward scatter (FSC), side scatter analysis by routine flow cytometry, with the presence of a distinct population of monocytes with high FSC (FSC-high). On more detailed analysis, these CD14+ CD16+ , FSC-high monocytes show features of mixed M1/M2 macrophage polarization with higher expression of CD80+ and CD206+ compared with the residual FSC-low monocytes and secretion of higher levels of IL-6, IL-10, and TNF-α, when compared with the normal controls. In conclusion, the detection and serial monitoring of this subset of inflammatory monocytes using flow cytometry could be of great help in guiding the prognostication and treatment of patients with COVID-19 and merits further evaluation.

The phenotypic changes of γδ T cells in COVID-19 patients.

A novel pneumonia-associated respiratory syndrome named coronavirus disease-2019 (COVID-19), which was caused by SARS-CoV-2，broke out in Wuhan, China, in the end of 2019. Unfortunately, there is no specific antiviral agent or vaccine available to treat SARS-CoV-2 infections. The information regarding the immunological characteristics in COVID-19 patients remains limited. Here, we collected the blood samples from 18 healthy donors (HD) and 38 COVID-19 patients to analyze changes on γδ T cell population. In comparison with HD, the γδ T cell percentage decreased, while the activation marker CD25 expression increased in response to SARS-CoV-2 infection. Interestingly, the CD4 expression was upregulated in γδ T cells reflecting the occurrence of a specific effector cell population, which may serve as a biomarker for the assessment of SARS-CoV-2 infection.

Naturally activated adaptive immunity in COVID-19 patients.

Coronavirus disease-2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus (SARS-CoV-2) has rapidly spread worldwide, threatening the health and lives of many people. Unfortunately, information regarding the immunological characteristics of COVID-19 patients remains limited. Herein, we collected blood samples from 18 healthy donors (HDs) and 38 COVID-19 patients to analyse changes in the adaptive immune cell populations and their phenotypes. We observed that the lymphocyte percentage moderately decreased, CD4 and CD8 T cell percentage among lymphocytes were similar, and B cell percentage was increased in COVID-19 patients in comparison to that in HDs. T cells, especially CD8 T cells, showed an enhanced expression of late activation marker CD25 and exhaustion marker PD-1. Importantly, SARS-CoV-2 infection increased the percentage of T follicular helper- and germinal centre B-like cells in the blood. The parameters in COVID-19 patients remained unchanged across various age groups. Therefore, we demonstrated that the T and B cells are activated naturally and are functional during SARS-CoV-2 infection. These data provide evidence that the adaptive immunity in most patients could be primed to induce a significant immune response against SARS-CoV-2 infection upon receiving standard medical care.

LAG-3 Represents a Marker of CD4+ T Cells with Regulatory Activity in Patients with Bone Fracture.

The lymphocyte activation gene 3 (LAG-3) is a CD4 homolog with binding affinity to MHC class II molecules. It is thought that LAG-3 exerts a bimodal function, such that co-ligation of LAG-3 and CD3 could deliver an inhibitory signal in conventional T cells, whereas, on regulatory T cells, LAG-3 expression could promote their inhibitory function. In this study, we investigated the role of LAG-3 expression on CD4+ T cells in patients with long bone fracture. We found that LAG-3+ cells represented approximately 13% of peripheral blood CD4+ T cells on average. Compared to LAG-3- CD4+ T cells, LAG-3+ CD4+ T cells presented significantly higher Foxp3 and CTLA-4 expression. Directly ex vivo or with TCR stimulation, LAG-3+ CD4+ T cells expressed significantly higher levels of IL-10 and TGF-ß than LAG-3- CD4+ T cells. Interestingly, blocking the LAG-3-MHC class II interaction actually increased the IL-10 expression by LAG-3+ CD4+ T cells. The frequency of LAG-3+ CD4+ T cell was positively correlated with restoration of healthy bone function in long bone fracture patients. These results together suggested that LAG-3 is a marker of CD4+ T cells with regulatory function; at the same time, LAG-3 might have limited the full suppressive potential of Treg cells.

Chronic Osteomyelitis Increases the Incidence of Type 2 Diabetes in Humans and Mice.

Background: To compare the risk of type 2 diabetes (T2DM) between patients with and without chronic osteomyelitis (COM), both in humans and in mice, and to explore risk factors in COM patients who developed T2DM. Methods: One hundred seven patients with COM and 114 patients without COM were consecutively enrolled and retrospectively analysed. Clinical data concerning the time to develop diabetes, glucose metabolism, lipid metabolism, inflammatory factors, mental health and frequency of specialist visits were collected. A mouse model of osteomyelitis was used to verify the presence of impaired glucose metabolism and depression. All data were processed by SPSS. Results: The incidence of T2DM was 2.37-fold higher in patients with COM than in those without. In COM patients, subjects with T2DM (DDM) had higher BMI, less exercise and more frequent visits to specialists than those without (Con). Glucose and lipid metabolism were worse in patients with DDM. Patients with DDM had higher levels of white blood cells (12.9±2.1×109/L vs. 11.7±2.2×109/L, p=0.027), CRP (28.4±4.5 mg/L vs. 22.0±4.8 mg/L, p<0.001), TNF-α (13.5±5.0 pg/mL vs. 9.4±2.6 pg/mL, p= 0.003) and IL-6 (12.9±3.2 pg/mL vs. 9.2±2.7 pg/mL, p<0.001). Significantly increased fasting blood glucose concentrations and impairment of oral glucose tolerance tests were also observed in mice modelling osteomyelitis, which were accompanied by elevated TNF-α and IL-6 levels. Furthermore, the proportion of depression (63.2% vs. 35.2%, p=0.003) and severe anxiety (31.6% vs. 9.1%, p=0.002) were significantly higher in the DDM group. Osteomyelitis mice showed obvious depressive-like behaviours. The levels of TNF-α, IL-6, CRP, BMI, and LDL; lack of exercise; SAS; HAQ; and SF36 assessment were risk factors for the development of T2DM in COM patients. Conclusions: Chronic osteomyelitis increased the incidence of T2DM in both humans and mice. Inflammation, mental illness and lack of exercise were risk factors for the occurrence of T2DM in osteomyelitis. Comprehensive consideration of patient history, including metabolism and mental health, is needed in planning future treatment.

Surgical Approach to Foreign Material Within the Mandibular Canal Due to Iatrogenic Factors.

This clinical report describes a relatively infrequent patient with inferior alveolar nerve damage caused by foreign material within the mandibular canal, which is one of the most severe complications of endodontic therapy. Although the circumstance is uncommon, it can have extremely unfavorable consequences for patients, such as anesthesia and paresthesia. In the present case, a patient suffered pain and severe paresthesia in the corresponding area after routine endodontic therapy. Several treatments were conducted to relieve the patient's symptoms, ranging from medication to tooth extraction, but all were of no avail. Ultimately, surgical exploration and debridement were performed with assistance of a customized surgical template. Once the foreign material was excavated, the exacerbation of condition was terminated and gradually reverted. This patient illustrates that special attention is required when undertaking intracanal procedures of lower posterior teeth so as to avoid iatrogenic damage to inferior alveolar nerve. Even more significant, when above-mentioned condition occurs, prompt surgical intervention is essential for recovery of sensation. It also demonstrates the advantages of applying surgical template and piezosurgery in removal of foreign material within the mandibular canal.

Probiotics protect mice from CoCrMo particles-induced osteolysis.

Wear particle-induced inflammatory osteolysis is the primary cause of aseptic loosening, which is the most common reason for total hip arthroplasty (THA) failure in the med- and long term. Recent studies have suggested an important role of gut microbiota (GM) in modulating the host metabolism and immune system, leading to alterations in bone mass. Probiotic bacteria administered in adequate amounts can alter the composition of GM and confer health benefits to the host. Given the inflammatory osteolysis that occurs in wear debris-induced prosthesis loosening, we examined whether the probiotic Lactobacillus casei could reduce osteolysis in a mouse calvarial resorption model. In this study, L. casei markedly protected mice from CoCrMo particles (CoPs)-induced osteolysis. Osteoclast gene markers and the number of osteoclasts were significantly decreased in L. casei-treated mice. Probiotic treatment decreased the M1-like macrophage phenotype indicated by downregulation of tumor necrosis factor α (TNF-α), interleukin (IL)-6 and inducible nitric oxide synthase (iNOS) and increased the M2-like macrophage phenotype indicated by upregulation of IL-4, IL-10 and arginase. Collectively, these results indicated that the L. casei treatment modulated the immune status and suppressed wear particle-induced osteolysis in vivo. Thus, probiotic treatment may represent a potential preventive and therapeutic approach to reduced wear debris-induced osteolysis.

STAT3 promotes bone fracture healing by enhancing the FOXP3 expression and the suppressive function of regulatory T cells.

Signal transducer and activator of transcription 3 (STAT3) is a key signaling protein in the skeletal system as well as in the immune system. Accumulating evidence demonstrates that the inflammatory response is deeply involved in the healing process of bone fractures, but how the immune system is regulated during this process is unclear. In this study, we examined STAT3-mediated regulation of immunity in adult patients with closed tibia fracture. In all patients, the expression and activation of STAT3 peaked at around day 7 to day 14 after surgery, and gradually decreased during the rest of the healing period. At day 7 (peak STAT3 expression and phosphorylation), the CD4+ CD25+ T cells from bone fracture patients presented the highest level of STAT3 activation among lymphocyte subsets. Therefore, we investigated the role of STAT3 in CD4+ CD25+ T cells. The level of FOXP3 expression by CD4+ CD25+ T cells was directly correlated with the level of STAT3 phosphorylation in these cells. The level of STAT3 phosphorylation in CD4+ CD25+ T cells was also inversely correlated with the level of IFN-γ and TNF-α secretion in peripheral blood mononuclear cells. Inhibition of STAT3 significantly suppressed FOXP3 and IL-10 expression by CD4+ CD25+ T cells, as well as the ability of CD4+ CD25+ T cells to suppress T-cell IFN-γ and TNF-α secretion. Furthermore, early healers patients presented significantly higher STAT3 expression and phosphorylation than late healers, possibly due to the higher IL-6 and IL-10 levels in the serum of early healing patients. Together, these data demonstrated that STAT3 was beneficial to bone fracture healing, possibly by enhancing Treg-mediated suppression of counteracting inflammations, and suggested that STAT3 could be used as a prognostic marker to identify otherwise undistinguishable patients at risk of developing delayed union or nonunion.

Expression of XBP1s in fibroblasts is critical for TiAl6 V4 particle-induced RANKL expression and osteolysis.

Wear particle-induced osteolysis is a major cause of aseptic loosening, which is one of the most common reasons for total hip arthroplasty (THA) failure. Previous studies have shown that the expression of Receptor activation of nuclear factor (NF)-kB (RANKL) by fibroblasts in periprosthetic membrane played a crucial role in wear particle-induced osteolysis. However, the underlying mechanism of RANKL expression remains largely unknown. In the present study, we investigated the effect of TiAl6 V4 particle (TiPs)-induced XBP1s (spliced form of X-box binding protein 1) on RANKL expression and osteoclastogenesis both in vitro and in vivo. The levels of XBP1s in peri-implant membrane, animal models, and TiPs-stimulated fibroblasts were determined by western blots. To assess the effect of XBP1s on RANKL expression, fibroblasts were treated with both a small interfering RNA (siRNA) and an inhibitor of XBP1 prior to exposure to TiPs. The effect of XBP1s on osteoclasts formation was determined by tartrate-resistant acid phosphatase (TRAP) staining in vitro osteoclastogenesis assay and in animal models. The resorption of bone was assessed by micro-computed tomography (micro-CT) with three-dimensional reconstruction. Our results demonstrated that XBP1s was activated in periprosthetic membrane, mouse calvaria models, and TiPs-stimulated human synovial fibroblasts. Further, inhibition of XBP1s decreased the expression of RANKL and osteoclasts formation in vitro. In mouse calvaria models, both of the osteoclastogenesis and osteolysis were inhibited XBP1s inhibitor. Our results suggested that XBP1s mediated TiPs-induced of RANKL expression in fibroblasts, and down regulating XBP1s may represent a potential therapy for wear particle-induced osteolysis. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:752-759, 2017.

Comparison of Monolateral External Fixation and Internal Fixation for Skeletal Stabilisation in the Management of Small Tibial Bone Defects following Successful Treatment of Chronic Osteomyelitis.

BACKGROUND: To compare the salvage rate and complication between internal fixation and external fixation in patients with small bone defects caused by chronic infectious osteomyelitis debridement. METHODS: 125 patients with chronic infectious osteomyelitis of tibia fracture who underwent multiple irrigation, debridement procedure, and local/systemic antibiotics were enrolled. Bone defects, which were less than 4 cm, were treated with bone grafting using either internal fixation or monolateral external fixation. 12-month follow-up was conducted with an interval of 3 months to evaluate union of bone defect. RESULTS: Patients who underwent monolateral external fixation had higher body mass index and fasting blood glucose, longer time since injury, and larger bone defect compared with internal fixation. No significant difference was observed in incidence of complications (23.5% versus 19.3%), surgery time (156 ± 23 minutes versus 162 ± 21 minutes), and time to union (11.1 ± 3.0 months versus 10.9 ± 3.1 months) between external fixation and internal fixation. Internal fixation had no significant influence on the occurrence of postoperation complications after multivariate adjustment when compared with external fixation. Furthermore, patients who underwent internal fixation experienced higher level of daily living scales and lower level of anxiety. CONCLUSIONS: It was relatively safe to use internal fixation for stabilization in osteomyelitis patients whose bone defects were less than 4 cm and infection was well controlled.

Regulatory B cell is critical in bone union process through suppressing proinflammatory cytokines and stimulating Foxp3 in Treg cells.

Bone fractures may result in delayed union (DU) or non-union (NU) in some patients. Evidence suggests that the skewing of the immune system toward the proinflammatory type is a contributing factor. Because B cells were previously found to infiltrate the fracture healing site at abundant levels, we examined the regulatory B cells (Bregs) in DU/NU patients. In bone fracture patients with normal healing, the frequency of interleukin (IL)-10-expressing B cells was significantly upregulated in the early healing process (6 weeks post-surgery) and was downregulated later on (18 weeks post-surgery), whereas in DU/NU patients, the early upregulation of IL-10-expressing B cells was missing. The majority of IL-10-expressing B cells were concentrated in the IgM+ CD27+ fraction in both controls and patients. IgM+ CD27+ B cells effectively suppressed interferon gamma (IFN-γ), tumor necrosis factor alpha (TNF-α), and IL-2 expression from CD4+ T cells, as well as IFN-γ and TNF-α expression from CD8+ T cells. The IgM+ CD27+ B cell-mediated suppression was restricted to the sample from the early healing time point in controls, as the IgM+ CD27+ B cells from normal healing patients later on or from DU/NU patients did not present significant regulatory function. In addition, culturing of CD4+ CD25+ Tregs with IgM+ CD27+ B cells from controls at early healing time point resulted in higher Foxp3 expression, a function absent in controls at later time point, or in DU/NU patients. In conclusion, our results support a role of B cell-mediated regulation early during the bone healing process.

Epigenetic Modification Mediates the Increase of LAG-3+ T Cells in Chronic Osteomyelitis.

Immune suppression plays critical roles in the development of chronic osteomyelitis, and the mechanisms underlying the development of immune suppression in chronic osteomyelitis have attracted much attention. LAG-3 is an important suppressor of T cell activation, but the role of LAG-3 in the immune regulation of chronic osteomyelitis is currently unknown. We sought to demonstrate if LAG-3 plays crucial roles in chronic osteomyelitis progression and has effects on immune suppression and exhausting of T cells, and what is the mechanism underlying LAG-3 deregulation in chronic osteomyelitis. We examined the expression of LAG-3 in the T cells of peripheral blood of 50 healthy controls and 50 patients with chronic osteomyelitis by flow cytometry. Clinical data were analyzed to determine the correlation between inflammation index and LAG-3 expression. Moreover, we isolated the CD4+ T cells from healthy controls and chronic osteomyelitis patients to compare cell proliferation and IFN-γ production. Chromatin immunoprecipitation assays were utilized to analyze the epigenetic modification on LAG-3 expression in T cells. We found that LAG-3 was significantly increased in the T cells of peripheral blood from chronic osteomyelitis patients. Subsequently, clinical data analysis suggested that the higher expression of LAG-3 was associated with severer inflammation situation. Consistently, LAG-3+CD4+ T cells exhibited impaired cell proliferation and IFN-γ secretion. Deregulation of histone methylation mediated the increase of LAG-3+ T cells during chronic osteomyelitis. Taken together, our study demonstrates the increase of LAG-3+ T cells and its immune regulatory roles in chronic osteomyelitis progression, suggesting new mechanisms and potential therapeutic targets for chronic osteomyelitis.

TiAl6V4 particles promote osteoclast formation via autophagy-mediated downregulation of interferon-beta in osteocytes.

Wear debris-induced osteolysis is the leading cause of aseptic loosening, which is the most common reason for total hip arthroplasty (THA) failure in the medium and long term. Although osteocytes are the most abundant cells in bone and make direct contact with implants, the interaction between osteocytes and wear debris remains largely unknown. In the present study, we investigated the effect of TiAl6V4 alloy particles (TiPs) on osteocytes and the subsequent effects on osteoclast formation. Our study demonstrated that osteocyte-conditioned medium (CM) inhibited osteoclast differentiation from bone marrow monocytes (BMMs) to osteoclasts. However, TiPs attenuated this inhibitory effect. The expression of several osteoclastogenesis-associated factors, including receptor activator of nuclear factor-kappaB ligand (RANKL), osteoprotegerin (OPG), nitric oxide (NO) and interferon-beta (IFN-ß), was examined, and we found that TiPs markedly decreased the expression of IFN-ß, but not the other factors. In an osteoclastogenesis assay, our results suggested that the downregulation of IFN-ß mediated the stimulatory effect of TiPs on osteoclastogenesis. Additional evidence suggested that TiPs decreased the expression of IFN-ß in osteocytes via macroautophagy (hereinafter referred to as "autophagy"). Moreover, inhibiting autophagy with Atg5 siRNA prevented the increase in osteoclastogenesis induced by TiPs. Collectively, these results suggested a possible mechanism underlying wear debris-induced osteolysis. STATEMENT OF SIGNIFICANCE: For the first time, our study demonstrated that Ti-alloy particles attenuated the inhibitory effect of osteocytes-conditioned medium on osteoclast formation. With an osteoclastogenesis assay, we found that the downregulation of IFN-ß in osteocytes mediated the promoting effect of TiPs on osteoclast formation. Furthermore, our results suggested that TiPs-induced autophagy mediated the downregulation of IFN-ß in osteocytes. Inhibition of autophagy recovered the expression of IFN-ß and ameliorated the promoting effect of TiPs on osteoclast formation. Collectively, these findings suggest a possible mechanism underlying wear debris-induced osteolysis and identified autophagy inhibition in osteocytes as a potential therapeutic approach for wear debris induced osteolysis.