Clinical characteristics, treatment and efficacy of calcaneal osteomyelitis: A systematic review with synthesis analysis 1118 reported cases.

BACKGROUND: Calcaneal osteomyelitis (CO) still poses great challenges to orthopaedic surgeons due to unique anatomic and functional features of the calcaneus. This study summarized the current data regarding clinical characteristics, treatment and efficacy of CO, based on an analysis of literature-reported cases. MATERIALS AND METHODS: We searched the PubMed, Embase, and Cochrane Library databases to find English and Chinese studies reporting on CO patients between 2000 and 2021, with available data for synthesis analysis. The quality of the included studies was evaluated by the National Institutes of Health (NIH) assessment scale. Effective data were extracted and pooled for analysis. RESULTS: Altogether 198 studies involving 1118 patients were included, with a male-to-female ratio of 2.3 (724 males and 310 females). The median age at CO diagnosis was 46 years, with a median symptom duration of 3 months. Injury-related infections (524 cases) and diabetic foot infections (336 cases) were the two most common causes, with ulcer (468 cases) and wound sinus or exudation (209 cases) being the predominant symptoms. The overall positive culture rate was 80.2%, with polymicrobial infections accounting for 18.1%. Staphylococcus aureus was the most frequently detected pathogen (42.7%), with fungal-related infections isolated in 17 cases. Although most patients received surgical interventions (96.9%), the recurrence rate was 20.1%. The incidence of infection relapse following partial calcanectomy, total calcanectomy, debridement with implantation of local antibiotics, and debridement with or without flap or skin coverage were 31.7%, 45.0%, 16.8%, and 15.1%, respectively. The overall incidence of limb amputation was 12.4%, with all-cause and CO-related mortalities of 2.8% and 0.2%, separately. CONCLUSIONS: CO shared similar characteristics with extremity chronic osteomyelitis, primarily affecting young males, with trauma and diabetic foot as the leading causes and Staphylococcus aureus as the most frequently detected pathogen. Despite surgery being the primary treatment modality, clinical outcomes remained unsatisfactory, marked by high rates of infection recurrence and limb amputation.

Similarities and Differences Between Diabetes-Related and Trauma-Related Calcaneal Osteomyelitis: Comparisons Based on 681 Reported Cases.

Background: Current information were still limited regarding clinical characteristics, diagnosis, and treatment efficacy of calcaneal osteomyelitis (CO). The present study summarized similarities and differences between diabetes-related CO (DRCO) and trauma-related CO (TRCO) based on synthesis analysis of literature-reported cases. Methods: We searched the PubMed, Embase, and Cochrane Library databases to find English studies reporting DRCO and TRCO published between January 2000 and December 2021. Effective data were extracted and synthesized for comparisons. Results: Altogether 108 studies with 278 DRCO and 403 TRCO patients were analyzed. The ratio of females among the DRCO patients was significantly higher than that of the TRCO patients (37.4% vs 24.3%, P < 0.001). The median age at diagnosis of the DRCO patients was statistically older than the TRCO patients (56 vs 44 years, P < 0.001). The median symptom duration of the DRCO patients was longer than the TRCO patients (4 vs 2 months, P = 0.136), with ulcer and sinus as the top symptoms for the DRCO and TRCO patients, respectively. The positive rate of pathogen culture for the DRCO patients was significantly higher than that for the TRCO patients (94.8% vs 69.5%, P < 0.001). The DRCO patients had higher risks of infection relapse (32.3% vs 16.3%, P < 0.001) and amputation (24.8% vs 1.4%, P < 0.001), and a higher all-cause mortality (4.9% vs 1.3%, P = 0.03) than the TRCO patients. Conclusion: DRCO and TRCO shared similar and different clinical features and diagnostic issues. However, compared with TRCO, the clinical efficacy and prognosis of DRCO were worse.

The Role of Senescence-Associated Secretory Phenotype in Bone Loss.

As the population of most nations have a large proportion of older individuals, there is an increase in the prevalence of osteoporosis. Consequently, scientists have focused their attention on the pathogenic mechanisms of osteoporosis. Owing to an increase in studies on cellular senescence in recent years, research has begun to focus on the function of the senescent microenvironment in osteoporosis. With chronic inflammation, senescent cells in the bone marrow secrete a series of factors known as senescence-associated secretory phenotype (SASP) factors, acting on their own or surrounding healthy cells and consequently exacerbating ageing.The components of the SASP may differ depending on the cause of osteoporosis. This review aimed to summarize the relationship between SASP factors and osteoporosis and suggest new insights into the mechanistic investigation of osteoporosis.

Higher serum apolipoprotein B level will reduce the bone mineral density and increase the risk of osteopenia or osteoporosis in adults.

Objective: There is very limited evidence in the NHANES database linking serum apolipoprotein B and lumbar bone mineral density (BMD) in adults aged 20-59 years. There are few studies associating apolipoprotein B concentrations with BMD, and there is some debate about the association between obesity and BMD. Therefore, the purpose of this study was to determine the association between serum apolipoprotein B concentrations and lumbar spine BMD in adults aged 20-59 years and to predict its association with risk of osteopenia or osteoporosis. Methods: A cross-sectional study of the entire US ambulatory population was conducted using data from the National Health and Nutrition Examination Survey (NHANES) database. Weighted multiple regression equation models were used to assess the association between serum apolipoprotein B and lumbar BMD. A logistic weighted regression model was used to assess the association between serum apolipoprotein B concentrations and risk of osteopenia or osteoporosis. Subsequent stratified analyses were performed to refine the primary population of association. Results: Our study showed a significant negative association between serum apolipoprotein B concentration and lumbar BMD and a significant positive association with the risk of osteoporosis or osteopenia in the total population. After stratifying by sex, age and race, we concluded differently. The association of serum apolipoprotein B concentration with lumbar spine BMD and risk of osteopenia or osteoporosis was significant in male, but not in female. After stratification by age, the negative association between serum apolipoprotein B concentrations and lumbar BMD and the positive association with risk of osteopenia or osteoporosis was more significant in the 30-39 and 50-59 years age groups. When stratified by race, serum apolipoprotein B concentrations were significantly negatively associated with lumbar BMD and positively associated with risk of osteopenia or osteoporosis in Mexican American and non-Hispanic black populations. Thus, these findings suggest that these associations are influenced by sex, age, and race, respectively. Conclusion: Our results suggest that the association between serum apolipoprotein B levels and the risk of lumbar BMD and osteopenia or osteoporosis varies by sex, age, and race. In men, elevated serum apolipoprotein B levels were negative for bone quality. Elevated serum apolipoprotein B levels in the age groups 30-39 and 50-59 years also had a negative effect on bone quality. In the Mexican American and Non-Hispanic Black populations, elevated serum apolipoprotein B levels also had a significant negative effect on bone quality.

High-Fat Diet Increases Bone Loss by Inducing Ferroptosis in Osteoblasts.

Current research suggests that chronic high-fat dietary intake can lead to bone loss in adults; however, the mechanism by which high-fat diets affect the development of osteoporosis in individuals is unclear. As high-fat diets are strongly associated with ferroptosis, whether ferroptosis mediates high-fat diet-induced bone loss was the focus of our current study. By dividing the mice into a high-fat diet group, a high-fat diet + ferroptosis inhibitor group and a normal chow group, mice in the high-fat group were given a high-fat diet for 12 weeks. The mice in the high-fat diet + ferroptosis inhibitor group were given 1 mg/kg Fer-1 per day intraperitoneally at the start of the high-fat diet. Microscopic CT scans, histological tests, and biochemical indicators of ferroptosis were performed on bone tissue from all three groups at the end of the modelling period. Mc3t3-E1 cells were also used in vitro and divided into three groups: high-fat medium group, high-fat medium+ferroptosis inhibitor group, and control group. After 24 hours of incubation in high-fat medium, Mc3t3-E1 cells were assayed for ferroptosis marker proteins and biochemical parameters, and osteogenesis induction was performed simultaneously. Cellular alkaline phosphatase content and expression of osteogenesis-related proteins were measured at day 7 of osteogenesis induction. The results showed that a high-fat diet led to the development of femoral bone loss in mice and that this process could be inhibited by ferroptosis inhibitors. The high-fat diet mainly affected the number of osteoblasts produced in the bone marrow cavity. The high-fat environment in vitro inhibited osteoblast proliferation and osteogenic differentiation, and significant changes in ferroptosis-related biochemical parameters were observed. These findings have implications for the future clinical treatment of bone loss caused by high-fat diets.

Elimination of Senescent Cells by Senolytics Facilitates Bony Endplate Microvessel Formation and Mitigates Disc Degeneration in Aged Mice.

Senolytics are a class of drugs that selectively eliminate senescent cells and ameliorate senescence-associated disease. Studies have demonstrated the accumulation of senescent disc cells and the production of senescence-associated secretory phenotype decrease the number of functional cells in degenerative tissue. It has been determined that clearance of senescent cell by senolytics rejuvenates various cell types in several human organs, including the largest avascular structure, intervertebral disc (IVD). The microvasculature in the marrow space of bony endplate (BEP) are the structural foundation of nutrient exchange in the IVD, but to date, the anti-senescence effects of senolytics on senescent vascular endothelial cells in the endplate subchondral vasculature remains unclear. In this study, the relationships between endothelial cellular senescence in the marrow space of the BEP and IVD degeneration were investigated using the aged mice model. Immunofluorescence staining was used to evaluate the protein expression of P16, P21, and EMCN in vascular endothelial cells. Senescence-associated ß-galactosidase staining was used to investigate the senescence of vascular endothelial cells. Meanwhile, the effects of senolytics on cellular senescence of human umbilical vein endothelial cells were investigated using a cell culture model. Preliminary results showed that senolytics alleviate endothelial cellular senescence in the marrow space of BEP as evidenced by reduced senescence-associated secretory phenotype. In the aged mice model, we found decreased height of IVD accompanied by vertebral bone mass loss and obvious changes to the endplate subchondral vasculature, which may lead to the decrease in nutrition transport into IVD. These findings may provide evidence that senolytics can eliminate the senescent cells and facilitate microvascular formation in the marrow space of the BEP. Targeting senescent cellular clearance mechanism to increase nutrient supply to the avascular disc suggests a potential treatment value of senolytics for IVD degenerative diseases.

Antimicrobial potency, prevention ability, and killing efficacy of daptomycin-loaded versus vancomycin-loaded ß-tricalcium phosphate/calcium sulfate for methicillin-resistant Staphylococcus aureus biofilms.

Growing evidence has shown that the efficacy of systemic administration of daptomycin for the treatment of methicillin-resistant Staphylococcus aureus (MRSA)-related infections is satisfactory. However, the clinical efficacy of the local administration of daptomycin for the management of osteoarticular infections remains unclear. This in vitro study compared the efficacy of daptomycin and vancomycin against MRSA biofilms. The elution kinetics of daptomycin and vancomycin, combined with gentamicin and loaded with either ß-tricalcium phosphate/calcium sulfate or calcium sulfate, in the presence of MRSA infection, was assessed. Their efficacy in preventing biofilm formation and killing pre-formed biofilms was assessed using colony-forming unit count and confocal laser scanning microscopy. In addition, the efficacy of daptomycin, vancomycin, and gentamicin in prophylaxis and eradication of MRSA biofilms was also evaluated. Daptomycin + gentamicin and vancomycin + gentamicin displayed similar antimicrobial potency against MRSA, by either ß-tricalcium phosphate/calcium sulfate or calcium sulfate. In the prevention assays, both daptomycin + gentamicin and vancomycin + gentamicin showed similar efficacy in preventing bacterial colony formation, with approximately 6 logs lower colony-forming units than those in the control group at both 1 and 3 days. The killing effect on pre-formed biofilms showed significant decreases of approximately 4 logs at 1 and 3 days following treatment with daptomycin + gentamicin and vancomycin + gentamicin. In addition, the confocal laser scanning microscopy results support the colony-forming unit data. Moreover, single use of vancomycin and gentamicin showed similar efficacies in preventing and killing MRSA biofilms, both of which were better than that of gentamicin. Our study demonstrated that vancomycin + gentamicin and daptomycin + gentamicin loaded with ß-tricalcium phosphate/calcium sulfate or calcium sulfate showed similar prophylactic and killing effects on MRSA biofilms, implying a potential indication of local administration daptomycin for the treatment of MRSA-associated osteoarticular infections, especially if vancomycin administration presents limitations.

Antenatal Corticosteroid Therapy Attenuates Angiogenesis Through Inhibiting Osteoclastogenesis in Young Mice.

Antenatal corticosteroid therapy (ACT) has been shown to reduce morbidity and mortality rates in preterm delivery, but the fetus is more likely to face the risk of low bone mineralization and low fetal linear growth. However, the mechanism of ACT inducing low bone mineralization remains largely unknown. Pre-osteoclasts, which play an important role in angiogenesis and osteogenesis, are specifically regulating type H vessels (CD31hiEmcnhi) and vessel formation by secreting platelet-derived growth factor-BB (PDGF-BB). We find that the number of pre-osteoclasts and POC-secreted PDGF-BB is dramatically decreased in ACT mice, contributing to the reduction in type H vessels and bone mineralization during the mouse offspring. Quantitative analyses of micro-computed tomography show that the ACT mice have a significant reduction in the mass of trabecular bone relative to the control group. Mononuclear pre-osteoclasts in trabecular bone decreased in ACT mice, which leads to the amount of PDGF-BB reduced and attenuates type H vessel formation. After sorting the Rank+ osteoclast precursors using flow cytometry, we show that the enhancer of zeste homolog 2 (Ezh2) expression is decreased in Rank+ osteoclast precursors in ACT mice. Consistent with the flow data, by using small molecule Ezh2 inhibitor GSK126, we prove that Ezh2 is required for osteoclast differentiation. Downregulating the expression of Ezh2 in osteoclast precursors would reduce PDGF-BB production. Conditioned medium from osteoclast precursor cultures treated with GSK126 inhibited endothelial tube formation, whereas conditioned medium from vehicle group stimulated endothelial tube formation. These results indicate Ezh2 expression of osteoclast precursors is suppressed after ACT, which reduced the pre-osteoclast number and PDGF-BB secretion, thus inhibiting type H vessel formation and ACT-associated low bone mineralization.