IFN-γ +874T/A polymorphism increases susceptibility to post-traumatic osteomyelitis.

Immunological inflammatory reaction is one of the key links in the occurrence and development of post-traumatic osteomyelitis after microbial invasion. Growing evidence suggests complex interactions between IFN-γ and bone remodelling cells. However, potential association of IFN-γ gene polymorphism with susceptibility to post-traumatic osteomyelitis remains unclear. This study aimed to investigate the potential link between IFN-γ +874T/A polymorphism and risk of developing post-traumatic osteomyelitis. A total of 189 patients with post-traumatic osteomyelitis and 200 healthy controls were enrolled for genotyping using the SNaPshot genotyping method. Statistically significant associations were found between the gene polymorphism and the risk of post-traumatic osteomyelitis by dominant model (AA + AT vs. TT, OR = 1.820, p = .017) and heterozygous model (AT vs. TT, OR = 1.781, p = .029). Moreover, the frequency of mutant allele A was significantly higher in the patients than that in the healthy controls (15.07% vs. 9.25%, OR = 1.742, p = .013). IFN-γ +874T/A polymorphism may contribute to the increased susceptibility to post-traumatic osteomyelitis.

Single-stage debridement with implantation of antibiotic-loaded calcium sulphate in 34 cases of localized calcaneal osteomyelitis.

Background and purpose - The successful eradication of calcaneus infection with limb salvage remains a challenge. We describe the outcomes of cortical bone windowing followed by eggshell-like debridement and implantation of antibiotic-loaded calcium sulphate (CS) for localized (Cierny-Mader type III) calcaneal osteomyelitis (CO).Patients and methods - We report a retrospective study of 34 patients. Infection followed trauma or orthopedic surgery in 30 patients and hematogenous spread in 4 patients. 31 patients had a sinus tract, accompanied by a soft tissue defect in 3 patients. All patients received cortical bone windowing, debridement, multiple sampling, local implantation of vancomycin- and gentamicin-loaded CS, skin closure or flap coverage, and culture-specific systematic antibiotic treatment in a single-stage procedure. Patients were followed up for a median of 26 months.Results - Infection was eradicated in 29 patients after the single-stage surgery, and all of the 5 recurrent infections were cleared by repeated surgery without amputation. Other adverse events included 11 patients with aseptic wound leakage and 1 unrelated death. Compared with those before surgery, the median postoperative scores of the American Orthopaedic Foot & Ankle Society (AOFAS) ankle hindfoot scale (65 vs. 86 vs. 89) and the visual analog scale (VAS) for pain (6 vs. 3 vs. 1) improved at the 1-year and 2-year follow-up.Interpretation - This single-stage protocol, cortical bone windowing, and eggshell-like debridement combined with local implantation of antibiotic-loaded CS is effective in treating type III CO. However, the incidence of aseptic wound leakage is high.

miR-193a inhibits osteogenic differentiation of bone marrow-derived stroma cell via targeting HMGB1.

BACKGROUND: miR-193a has been shown to be involved in a variety of biological processes, including cell proliferation, differentiation, and apoptosis. However, little is known about how miR-193a regulates osteogenic differentiation. METHODS: We employed RT-qPCR to determine the level of miR-193a and mRNA level of HMGB1 and osteoblast-specific markers (Runx2, ALP, OSX, OCN). Besides, westernblot was used to probe protein level of phosphorylated MAPK family members and ß-catenin. Bioinformatic analysis was used to predict the putative binding sequence of miR-193a to the 3'-UTR of HMGB1 and we confirmed this result by dual luciferase reporter assay. Alizarin red staining assay (ARS) and alkaline phosphatase activity (ALP) were performed to detect osteogenic differentiation. RESULTS: miR-193a was downregulated in OM (osteogenic medium)induced hBMSC. More interestingly, we found that miR-193a mimic attenuated matrix mineralization and alkaline phosphatase activity, whereas miR-193a inhibitor exerted the opposite phenotypes. Mechanistically, we observed that miR-193a played an inhibitory role in expression of osteoblast-specific markers and activation of MAPK and Wnt signaling pathways. Bioinformatic analysis and dual luciferase assay demonstrated that miR-193a directly targeted 3'-UTR of HMGB1. Furthermore, we overexpressed HMGB1 in miR-193a overexpressed hBMSC to establish that HMGB1 acted as downstream target of miR-193a-inhibited osteogenic differentiation. CONCLUSIONS: Here, we reveal miR-193a plays a suppressive role in osteogenic differentiation of hBMSC via targeting HMGB1. These findings provide a novel mechanism underlying osteogenic differentiation and offer therapeutical strategy for bone formation.

The comparison of adductor canal block with femoral nerve block following total knee arthroplasty: a systematic review with meta-analysis.

PURPOSE: Although several studies have compared the clinical efficacy of an adductor canal block (ACB) to that of a femoral nerve block (FNB) for analgesia after total knee arthroplasty (TKA), disputes mainly exist in the recovery of quadriceps strength and mobilization ability between the two methods. The aim of the present study was to compare, in a systematic review and meta-analysis, the clinical efficacy of ACB with that of FNB. METHODS: We systematically searched randomized controlled trials comparing FNB with ACB for analgesia after TKA in Pubmed and the Cochrane Library from inception to April 30th 2015. There was no limitation of publication language. Trial quality was assessed using the modified Jadad scale, and eligible data were pooled for meta-analysis. RESULTS: Five studies of 348 patients were included. Outcomes showed that patients who received ACB had similar or better recovery of quadriceps strength and mobilization ability than those that underwent FNB. Similar efficacy was found between the two strategies regarding adductor strength, pain scores [at rest (p = 0.86), at or after knee flexion (p = 0.31)], opioid consumption (p = 0.99), opioid-associated adverse effects (p = 0.60), length of hospital stay (p = 0.42), patient satisfaction (p = 0.57), and success rate of blockade (p = 0.20). CONCLUSIONS: The present study suggests that TKA patients who receive ACB can achieve similar or even better recovery of quadriceps strength and mobilization ability than those treated with FNB. Taken as a whole, ACB may be a better analgesia strategy after TKA at present.

Artificial nerve graft constructed by coculture of activated Schwann cells and human hair keratin for repair of peripheral nerve defects.

Studies have shown that human hair keratin (HHK) has no antigenicity and excellent mechanical properties. Schwann cells, as unique glial cells in the peripheral nervous system, can be induced by interleukin-1ß to secrete nerve growth factor, which promotes neural regeneration. Therefore, HHK with Schwann cells may be a more effective approach to repair nerve defects than HHK without Schwann cells. In this study, we established an artificial nerve graft by loading an HHK skeleton with activated Schwann cells. We found that the longitudinal HHK microfilament structure provided adhesion medium, space and direction for Schwann cells, and promoted Schwann cell growth and nerve fiber regeneration. In addition, interleukin-1ß not only activates Schwann cells, but also strengthens their activity and increases the expression of nerve growth factors. Activated Schwann cells activate macrophages, and activated macrophages secrete interleukin-1ß, which maintains the activity of Schwann cells. Thus, a beneficial cycle forms and promotes nerve repair. Furthermore, our studies have found that the newly constructed artificial nerve graft promotes the improvements in nerve conduction function and motor function in rats with sciatic nerve injury, and increases the expression of nerve injury repair factors fibroblast growth factor 2 and human transforming growth factor B receptor 2. These findings suggest that this artificial nerve graft effectively repairs peripheral nerve injury.

Vitamin D Receptor Genetic Polymorphisms Associate With a Decreased Susceptibility to Extremity Osteomyelitis Partly by Inhibiting Macrophage Apoptosis Through Inhibition of Excessive ROS Production via VDR-Bmi1 Signaling.

Background: Previous studies had reported that vitamin D receptor (VDR) gene polymorphisms were related to the development of several inflammatory disorders. However, potential links between such variations and the risk of developing a bone infection and underlying mechanisms remain unclear. This study aimed to analyze potential associations between VDR genetic variations and susceptibility to extremity osteomyelitis (OM) in a Chinese Han population and investigate potential mechanisms. Methods: Between January 2016 and August 2020, altogether 398 OM patients and 368 healthy controls were genotyped for six VDR gene polymorphisms, including ApaI (rs7975232), BsmI (rs1544410), FokI (rs2228570), TaqI (rs731236), GATA (rs4516035), and Cdx-2 (rs11568820) by the SNaPshot genotyping method. Then, male C57BL/6 mice were randomly divided into vitamin D-standard, -excess, -deficient, and -rescued groups. One week after making the model surgery, OM occurrence and severity were assessed using the bacterial count and histopathological staining. In vitro, phagocytosis, apoptosis, and bactericidal ability of macrophages were evaluated by overexpression or knockdown of VDR protein. Results: Significant associations were found among rs7975232, rs1544410, and OM development by the recessive model (AA vs. AC + CC, p = 0.037, OR = 0.594), homozygous model (AA vs. CC, p = 0.033, OR = 0.575), and heterozygous model (CT vs. CC, p = 0.049, OR = 0.610), respectively. Patients with the AA genotype of rs7975232 had a relatively higher mean level of vitamin D than those with AC and CC genotypes (22.5 vs. 20.7 vs. 19.0 ng/ml). Similarly, patients with CT genotype of rs1544410 had a relatively higher mean vitamin D level than those with CC genotype (20.94 vs. 19.89 ng/ml). Outcomes of in vivo experiments showed that the femoral bacterial load of vitamin D-deficient mice was highest among different vitamin D dose groups, with the most severe histopathological features of infection, and vitamin D supplementation partly reversed the changes. While in vitro experiment results revealed that active vitamin D promoted phagocytosis and sterilization of macrophages and inhibited apoptosis during infection. Reactive oxygen species (ROS) inhibitor inhibited apoptosis of macrophages induced by bacterial infection. Active vitamin D inhibited excessive ROS production in macrophages via the VDR-Bmi1 signaling pathway. Conclusion: In this Chinese cohort, ApaI and BsmI are associated with a decreased risk of OM development by influencing serological vitamin D level, the latter of which reduced macrophage apoptosis with inhibition of excessive ROS production via the VDR-Bmi1 signaling pathway.

Vitamin D Receptor Genetic Variations May Associate with the Risk of Developing Late Fracture-Related Infection in the Chinese Han Population.

Variations in the vitamin D receptor (VDR) gene are related to several inflammatory disorders. However, the potential links between such alternations and the risk of developing late fracture-related infection (FRI) remain unclear. This study investigated associations between genetic variations in the VDR and susceptibility to late FRI in the Chinese Han population. Between January 2016 and December 2019, 336 patients with late FRI and 368 healthy controls were genotyped six VDR genetic variations, including ApaI (rs7975232), BsmI (rs1544410), FokI (rs2228570), TaqI (rs731236), GATA (rs4516035), and Cdx-2 (rs11568820). Significant associations were observed between rs7975232 and FRI susceptibility in the recessive (P = 0.019, OR = 0.530, 95% CI 0.310-0.906) model. Patients with AA genotype had a relatively higher level of serological vitamin D (20.6 vs. 20.3 vs. 17.9 ng/ml) (P = 0.021) than those of AC and CC genotypes. Although no statistical differences were observed, potential correlations may exist between rs1544410 (dominant model: P = 0.079, OR = 0.634), rs2228570 (dominant model: P = 0.055, OR = 0.699), and rs4516035 (dominant model: P = 0.065, OR = 1.768) and the risk of FRI development. In the Chinese cohort, ApaI was associated with a decreased risk of developing FRI, and patients with the AA genotype had a higher vitamin D level. Further studies are required to assess the role of genetic variations in BsmI, FokI, and GATA in the pathogenesis of late FRI.

Interleukin-6 versus Common Inflammatory Biomarkers for Diagnosing Fracture-Related Infection: Utility and Potential Influencing Factors.

Currently, the utility of white blood cell count (WBC), erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP), for diagnosis of fracture-related infection (FRI), is still controversial, and potential efficiency of interleukin-6 (IL-6) as a novel cytokine in assisted diagnosis of FRI remains unclear. This study is aimed at investigating the utility and potential influencing factors of IL-6 and the common biomarkers for diagnosing FRI. Preoperative serological levels of IL-6 and the three biomarkers were compared between 407 FRI patients and 195 fracture-healed (FH) patients. Diagnostic efficiency of the indicators was evaluated using the areas under the receiver operating characteristic (ROC) curves, and their potential influencing factors were also analyzed. Outcomes showed that the median levels of all of the four biomarkers were significantly higher among the FRI patients than those among the FH patients (P < 0.01). The areas below the ROC curves of ESR, CRP, and IL-6 were 76.5%, 76.4%, and 71.8%, respectively, with WBC of only 56.9%. Compared with ESR and CRP, IL-6 displayed a lower sensitivity (ESR vs. CRP vs. IL - 6 = 72.7% vs. 65.6% vs. 57.5%) but a higher specificity (ESR vs. CRP vs. IL - 6 = 70.3% vs. 75.4% vs. 83.6%). Serological IL-6 level was influenced by pathogen culture result and pathogen number; nonetheless, bacteria type appeared to have no influence on the levels of the four biomarkers. In short, this study displayed similar value of IL-6 with that of ESR and CRP in assisted diagnosis of FRI. Whether IL-6 can be regarded as a promising diagnostic indicator requires more studies.

Galectin-3 and TRIM16 coregulate osteogenic differentiation of human bone marrow-derived mesenchymal stem cells at least partly via enhancing autophagy.

BACKGROUND: The osteogenic differentiation of human bone marrow-derived mesenchymal stem cells (hBMSCs) is critical for bone homeostasis. Here, we investigated the regulation of Galectin-3 and tripartite motif protein 16 (TRIM16) on osteogenic differentiation of hBMSCs through autophagy. METHODS: Quantitative PCR (qPCR) and western blot were performed to determine the expression of osteogenic markers, autophagic markers, Galectin-3 and TRIM16. Short-hairpin RNAs (shRNAs) and overexpression plasmids were used to manipulate the expression of Galectin-3, TRIM16 and Unc-51 like autophagy activating kinase 1 (ULK1). Alkaline phosphatase (ALP) activity was measured by ALP staining assay. Calcium deposition in differentiated hBMSCs was assessed by Alizarin Red S staining. LC3 puncta formation was monitored by immunofluorescence staining. The interaction between indicated proteins was confirmed by co-immunoprecipitation (Co-IP) assay. RESULTS: Either Galectin-3 or TRIM16 knockdown led to impaired ALP activity, reduced calcium deposition, down-regulation of pro-osteogenic markers as well as restrained autophagy in osteogenic-induced hBMSCs. However, overexpression of Galectin-3 or TRIM16 promoted osteogenic differentiation of hBMSCs, which was then compromised by autophagy inhibition. Co-IP experiment demonstrated that TRIM16 associated with Galectin-3 through ULK1. Meanwhile, osteogenic induction enhanced the association between TRIM16 and ULK1 or coiled-coil myosin-like BCL2-interacting protein (Beclin1), and TRIM16 increased the stability of ULK1 and Beclin1. Moreover, either TRIM16 or ULK1 knockdown dampened the pro-osteogenic effect of Galectin-3, which elucidated that Galectin-3 mediated osteogenic differentiation was at least partly dependent on TRIM16 and ULK1. CONCLUSION: In summary, the present study revealed Galectin-3 and TRIM16 co-regulated osteogenic differentiation of hBMSCs at least partly via enhancing autophagy, which might provide a promising approach for osteoporosis treatment in future.

Association of vitamin D receptor gene TaqI, BsmI, FokI and ApaI polymorphisms and susceptibility to extremity chronic osteomyelitis in Chinese population.

Previous studies have indicated that vitamin D receptor (VDR) TaqI, BsmI, FokI and ApaI gene polymorphisms are associated with the risk of several inflammatory diseases. However, potential association of the VDR gene polymorphisms with susceptibility to extremity chronic osteomyelitis remains unclear. The present study aimed to investigate link between VDR gene polymorphisms and the risk of extremity chronic osteomyelitis in Chinese population. A total of 233 patients with chronic osteomyelitis and 200 healthy controls were genotyped for the 4 single-nucleotide polymorphisms (SNPs) (TaqI, BsmI, FokI and ApaI) in VDR gene using the SNaPshot genotyping method. The frequencies of mutant allele C in rs731236 (P=0.044, OR=1.830, 95% CI 1.009 - 3.319) and rs2228570 (P=0.029, OR=1.347, 95% CI 1.031 - 1.761) were significantly higher in patients than those in healthy controls. In addition, outcomes of the logistic regression analysis adjusted by gender and age revealed that significant links were found between rs731236 (P=0.05, OR=1.887, 95% CI 1.001 - 3.558), rs2228570 (P=0.042, OR=1.594, 95% CI 1.016-2.500) and the risk of developing chronic osteomyelitis by dominant genetic model. In addition, significant association was also found between rs2228570 and the risk of developing the disease by homozygous model (P=0.034, OR=1.803, 95% CI 1.046 - 3.106). However, no significant correlations were found between BsmI (rs1544410) or ApaI (rs7975232) gene polymorphisms and the susceptibility to the disease. To our knowledge, we reported for the first time that VDR gene TaqI (rs731236) and FokI (rs2228570) polymorphisms may contribute to the increased risk of chronic osteomyelitis in Chinese population.

Clinical Characteristics and Treatment of Extremity Chronic Osteomyelitis in Southern China: A Retrospective Analysis of 394 Consecutive Patients.

Although extremity chronic osteomyelitis is common in China, updated data were still limited regarding its characterizations. The present study aimed to review clinical features of extremity chronic osteomyelitis in Southern China.A retrospective analysis was conducted in the patients who had sought medical attention from January 2010 to April 2015 for extremity chronic osteomyelitis in Nanfang Hospital in Southern China. Clinical data were collected and analyzed.A total of 394 patients (307 males and 87 females) were included, giving a gender ratio of 3.53. The median age at first diagnosis was 42 years for all. The most frequent type was traumatic osteomyelitis (262 cases, 66.50%), which was mainly caused by open injury (166 cases, 63.36%) and during a road accident (91 cases, 34.73%). Single-site infection accounted for 81.98% (323 cases), with tibia (126 cases), femur (79 cases), calcaneus (37 cases), and toes (37 cases) as the top sites. The positive rate of intraoperative culture was 70.63% (214/303), 78.97% (169/214) of which was monomicrobial infection. Staphylococcus aureus (59 cases) was the most frequent bacteria for monomicrobial infection, followed by Pseudomonas aeruginosa (29 cases) and Escherichia coli (11 cases). The positive ratios of preoperative serum white blood cell (WBC), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), procalcitonin (PCT), interleukin-6 (IL-6), and tumor necrosis factor alpha (TNF-α) were 21.63%, 64.92%, 53.27%, 42.25%, 72.82%, and 66.67%, respectively. The most frequently used intravenous antibiotic was cephalosporins. The overall cure rate was 77.74%, with a total amputation rate of 16.75%.In this representative Chinese cohort, extremity chronic osteomyelitis was mostly caused by open injury and during a road accident, predominated in males and favored the tibia. S. aureus was the most frequent pathogenic organism. Preoperative elevated levels of serum IL-6, TNF-α, and ESR may be helpful diagnostic indicators of the disease. Most patients achieved a favorable clinical efficacy after appropriate treatment.