Variation in the IL1B, TNF and IL6 genes and individual susceptibility to prosthetic joint infection

Integrating Genome-wide Polygenic Risk Scores with Non-genetic Models to Predict Surgical Site Infection after Total Knee Arthroplasty Using United Kingdom Biobank Data

BACKGROUND

Prediction of the risk of developing surgical site infection (SSI) in patients following total knee arthroplasty (TKA) is of clinical importance. Genetic susceptibility is involved in developing TKA-related SSI. Previously reported models for predicting SSI were constructed using non-genetic risk factors without incorporating genetic risk factors. To address this issue, we performed a genome-wide association study (GWAS) using the UK Biobank database.

METHODS

Adult patients who underwent primary TKA (n = 19,767) were analyzed and divided into SSI (n = 269) and non-SSI (n = 19,498) cohorts. Non-genetic covariates, including demographic data and preoperative comorbidities, were recorded. Genetic variants associated with SSI were identified by GWAS and included to obtain standardized polygenic risk scores (zPRS, an estimate of genetic risk). Prediction models were established through analyses of multivariable logistic regression and the receiver operating characteristic (ROC) curve.

RESULTS

There were four variants (rs117896641, rs111686424, rs8101598, and rs74648298) achieving genome-wide significance that were identified. The logistic regression analysis revealed seven significant risk factors: increasing zPRS, decreasing age, men, chronic obstructive pulmonary disease, diabetes mellitus, rheumatoid arthritis, and peripheral vascular disease. The areas under the ROC curve (AUC) were 0.628 and 0.708 when zPRS (model 1) and non-genetic covariates (model 2) were used as predictors, respectively. The AUC increased to 0.76 when both zPRS and non-genetic covariates (model 3) were used as predictors. A risk-prediction nomogram was constructed based on model 3 to visualize the relative effect of statistically significant covariates on the risk of SSI and predict the probability of developing SSI. Age and zPRS were the top two covariates that contributed to the risk, with younger age and higher zPRS associated with higher risks.

CONCLUSION

Our GWAS identified four novel variants that were significantly associated with susceptibility to SSI following TKA. Integrating genome-wide zPRS with non-genetic risk factors improved the performance of the model in predicting SSI.

Periprosthetic joint infection and immunity: Current understanding of host-microbe interplay

Periprosthetic joint infection (PJI) is a major complication of total joint arthroplasty. Even with current treatments, failure rates are unacceptably high with a 5-year mortality rate of 26%. Majority of the literature in the field has focused on development of better biomarkers for diagnostics and treatment strategies including innovate antibiotic delivery systems, antibiofilm agents, and bacteriophages. Nevertheless, the role of the immune system, our first line of defense during PJI, is not well understood. Evidence of infection in PJI patients is found within circulation, synovial fluid, and tissue and include numerous cytokines, metabolites, antimicrobial peptides, and soluble receptors that are part of the PJI diagnosis workup. Macrophages, neutrophils, and myeloid-derived suppressor cells (MDSCs) are initially recruited into the joint by chemokines and cytokines produced by immune cells and bacteria and are activated by pathogen-associated molecular patterns. While these cells are efficient killers of planktonic bacteria by phagocytosis, opsonization, degranulation, and recruitment of adaptive immune cells, biofilm-associated bacteria are troublesome. Biofilm is not only a physical barrier for the immune system but also elicits effector functions. Additionally, bacteria have developed mechanisms to evade the immune system by inactivating effector molecules, promoting killing or anti-inflammatory effector cell phenotypes, and intracellular persistence and dissemination. Understanding these shortcomings and the mechanisms by which bacteria can subvert the immune system may open new approaches to better prepare our own immune system to combat PJI. Furthermore, preoperative immune system assessment and screening for dysregulation may aid in developing preventative interventions to decrease PJI incidence.

Diagnosis of Periprosthetic Joint Infection: The Utility of Biomarkers in 2023

Periprosthetic joint infection (PJI) is a rare yet devastating complication following total joint arthroplasty (TJA). Early and accurate diagnosis of PJI is paramount in order to maximize the chances of successful treatment. However, we are yet to identify a single "gold standard" test for the diagnosis of PJI. As a result, the diagnosis of PJI is often challenging. Currently, the 2018 ICM definition of PJI is the only validated diagnostic criteria available. This article will review the importance of serum and synovial biomarkers in the diagnosis of PJI. In addition, it will provide a brief overview of the emerging modalities for the identification of infections in this setting.

The Ratio of IL-6 to IL-4 in Synovial Fluid of Knee or Hip Performances a Noteworthy Diagnostic Value in Prosthetic Joint Infection

The diagnosis of prosthetic joint infection (PJI) is still a challenge, the ratio of interleukin-6 (IL-6) to IL-4 in the joint fluid of knee or hip was used to analyze whether the diagnostic accuracy of PJI can be improved. Between January 2017 and May 2022, 180 patients who developed pain after revision total hip or knee arthroplasty were enrolled retrospectively. 92 patients of PJI and 88 of aseptic failure were included. PJI was as defined by the Musculoskeletal Infection Society (MSIS). The content of IL-6 and IL-4 in synovial fluid of knee or hip were measured, and the areas under the receiver operating characteristic curve (ROC) and IL-6/IL-4 curve were analyzed to obtain a better diagnostic effect. The area under the curve of IL-6/IL-4 in synovial fluid of knee or hip was 0.9623, which was more accurate than ESR 0.5994 and C-reactive protein 0.6720. The optimal threshold of IL-6/IL-4 ratio was 382.10. Its sensitivity and specificity were 81.32% and 98.86%, respectively. The positive predictive value for the diagnosis of PJI was 98.91%. This study showed that the level of IL-6/IL-4 in synovial fluid of knee or hip could further improve the diagnostic accuracy for PJI.

IL-1 β gene (+3954 C/T, exon 5, rs1143634) and NOS2 (exon 22) polymorphisms associate with early aseptic loosening of arthroplasties

Aseptic prosthetic loosening (APL) and prosthetic joint infections (PJI) are frequent complications of hip and knee implants. Polymorphisms of cytokines and nitric oxide (NO), key inflammatory molecules in APL and PJI pathogenesis, could explain individual susceptibility to these complications. Three cytokines (IL-1-a, IL-1-β, TNF-α) and two nitric oxide synthase (NOS2, NOS3) genes polymorphisms were genotyped in 77 APL and 117 PJI patients and 145 controls with aseptic hip or knee implants that were implanted for > 16 years. Plasma cytokines and nitrate-nitrite (NOx) levels also were measured. The TT genotype and T allele of (+3954 C/T, exon 5, rs1143634) IL-1β polymorphism were more frequent in APL patients compared to controls (P = 0.03 and P = 0.02, respectively). No genotypic associations in PJI patients were observed. Plasma IL-6, TNF-α and NOx were significantly different between APL and controls (P < 0.0001). Plasma IL-1β and IL-6 were significantly higher in APL T allele carriers vs. non-carriers (P < 0.03). Knee implant (HR 2.488, 95% CI 1.307-4.739, P = 0.005), male gender (HR 2.252, 95% CI 1.121-4.525, P = 0.023), carriages of the TT genotype of the (+3954 C/T) IL-1β polymorphism (HR 3.704, 95% CI 1.274-10.753, P = 0.016) and AA genotype of the (exon 22) NOS2 polymorphism (HR 3.509, 95% CI 1.266-9.709, P = 0.016) were independently associated with a shorter implant survival by Cox regression. No genotypic associations in PJI patients were observed. Genotyping of IL-1β (+3954 C/T, exon 5, rs1143634) and NOS2 (exon 22) polymorphisms could be useful as predictors of early hip or knee APL.

Genetic Polymorphisms Associated with Perioperative Joint Infection following Total Joint Arthroplasty: A Systematic Review and Meta-Analysis

The number of orthopedic procedures, especially prosthesis implantation, continues to increase annually, making it imperative to understand the risks of perioperative complications. These risks include a variety of patient-specific factors, including genetic profiles. This review assessed the current literature for associations between patient-specific genetic risk factors and perioperative infection. The PRISMA guidelines were used to conduct a literature review using the PubMed and Cochrane databases. Following title and abstract review and full-text screening, eight articles remained to be reviewed—all of which compared single nucleotide polymorphisms (SNPs) to periprosthetic joint infection (PJI) in total joint arthroplasty (TJA). The following cytokine-related genes were found to have polymorphisms associated with PJI: TNFα (p < 0.006), IL-6 (p < 0.035), GCSF3R (p < 0.02), IL-1 RN-VNTR (p = 0.002), and IL-1B (p = 0.037). Protein- and enzyme-related genes that were found to be associated with PJI included: MBL (p < 0.01, p < 0.05) and MBL2 (p < 0.01, p < 0.016). The only receptor-related gene found to be associated with PJI was VDR (p < 0.007, p < 0.028). This review compiled a variety of genetic polymorphisms that were associated with periprosthetic joint infections. However, the power of these studies is low. More research must be conducted to further understand the genetic risk factors for this serious outcome.

Risk of Revision After Arthroplasty Associated with Specific Gene Loci: A Genomewide Association Study of Single-Nucleotide Polymorphisms in 1,130 Twins Treated with Arthroplasty

BACKGROUND

The risk of revision surgery following total joint arthroplasty (TJA) may be influenced by genetic factors. Therefore, we sought to identify genetic variants associated with the risk of revision surgery in a genomewide association study.

METHODS

We investigated a cohort of 1,130 twins from the Swedish Twin Registry treated with TJA. During a mean of 9.4 years of follow-up, 75 individuals underwent revision surgery for aseptic loosening (the primary outcome) and 94, for any reason (the secondary outcome). Genetic information was collected using the Illumina OmniExpress and PsychArray panels, and the Haplotype Reference Consortium served as the reference for gene imputation. Adjusted Cox regression models were fitted to calculate hazard ratios (HRs) with 95% confidence intervals (CIs).

RESULTS

Nine single-nucleotide polymorphisms (SNPs) reached genomewide significance for aseptic loosening. The first SNP, rs77149046, located in the endosome-lysosome associated apoptosis and autophagy regulator family member 2 (ELAPOR2) gene, conferred an HR of 5.40 (CI, 3.23-9.02; p = 1.32×10 -10 ), followed by 4 SNPs within the region coding for sodium-dependent taurine and beta-alanine transporter (SLC6A6), with HRs ranging from 3.35 to 3.43. The sixth SNP, rs7853989 (HR, 3.46; CI, 2.33-5.13; p = 6.91×10 -10 ), was located in a region coding for the ABO blood group system. This SNP has been described as predictive for blood type B. Seven significant SNPs were found for the risk of revision for any reason, with the first 4 again being located in the SLC6A6 region. The leading SNP, rs62233562, conferred an HR of 3.11 (CI, 2.19-4.40; p = 1.74×10 -10 ) for revision surgery. Similar HRs were found for SNPs 3:14506680 (p = 1.78×10 -10 ), rs2289129 (p = 1.78×10 -10 ), and rs17309567 (p = 3.16×10 -10 ). The fifth SNP, rs11120968, was located in the calmodulin-binding transcription activator 1 (CAMTA1) gene (HR, 2.34; CI, 1.74-3.13, p = 1.45×10 -8 ).

CONCLUSIONS

We identified 12 unique SNPs associated with an increased risk of revision surgery. Among these, 2 were in ELAPOR2, which is closely linked to bone formation. Another SNP is located in a gene region encoding for the ABO system, which merits further studies of causal relationships.

LEVEL OF EVIDENCE

Prognostic Level III . See Instructions for Authors for a complete description of levels of evidence.

Novel Biomarkers for Diagnosing Periprosthetic Joint Infection from Synovial Fluid and Serum

Background:

Synovial fluid bacterial culture is the cornerstone of confirmation or exclusion of periprosthetic joint infection (PJI). The aim of this study was to assess synovial fluid and serum biomarker patterns of patients with total joint arthroplasty (TJA), and the association of these patterns with PJI.

Methods:

Synovial fluid and serum samples were collected from 35 patients who were admitted to the Arthroplasty Unit of the Department of Orthopaedics and Traumatology at Turku University Hospital. Of the 25 patients who were included in the study, 10 healthy patients with an elective TJA for osteoarthritis served as the control group, and 15 patients who were admitted due to clinical suspicion of PJI with local redness, swelling, wound drainage, pain, and/or fever and who had a positive synovial fluid bacterial culture served as the study group. Logistic regression was used to assess the ability of 37 biomarkers (including cytokines, chemokines, and growth factors) with commercially available tests to detect PJIs.

Results:

In synovial fluid, the concentrations of sTNF-R1 and sTNF-R2 (soluble tumor necrosis factor receptors 1 and 2) and BAFF (B-cell activating factor, also known as TNFSF13B) were significantly higher in the PJI group (p < 0.002). In serum, the sTNF-R1 concentration was significantly higher in the PJI group, whereas the TWEAK (tumor necrosis factor-like weak inducer of apoptosis) and osteocalcin concentrations were significantly lower (p < 0.002). The sensitivity for detecting PJI using synovial fluid was 1.00 for sTNF-R2, 0.93 for sTNF-R1, and 0.87 for BAFF/TNFSF13B. The specificity of all 3 synovial markers was 1.00. The sensitivity using serum was 0.80 for TWEAK, 0.73 for sTNF-R1, and 0.80 for osteocalcin. The specificity of all 3 serum markers was 1.00.

Conclusions:

Synovial sTNF-R2 is a promising new biomarker for detecting PJI. We are not aware of any previous reports of the use of sTNF-R2 in PJI diagnosis. More research is needed to assess the clinical importance of our findings.

Level of Evidence:

Diagnostic Level II. See Instructions for Authors for a complete description of levels of evidence.

Association of six CpG-SNPs in the inflammation-related genes with coronary heart disease

Background

Chronic inflammation has been widely considered to be the major risk factor of coronary heart disease (CHD). The goal of our study was to explore the possible association with CHD for inflammation-related single nucleotide polymorphisms (SNPs) involved in cytosine-phosphate-guanine (CpG) dinucleotides. A total of 784 CHD patients and 739 non-CHD controls were recruited from Zhejiang Province, China. Using the Sequenom MassARRAY platform, we measured the genotypes of six inflammation-related CpG-SNPs, including IL1B rs16944, IL1R2 rs2071008, PLA2G7 rs9395208, FAM5C rs12732361, CD40 rs1800686, and CD36 rs2065666). Allele and genotype frequencies were compared between CHD and non-CHD individuals using the CLUMP22 software with 10,000 Monte Carlo simulations.

Results

Allelic tests showed that PLA2G7 rs9395208 and CD40 rs1800686 were significantly associated with CHD. Moreover, IL1B rs16944, PLA2G7 rs9395208, and CD40 rs1800686 were shown to be associated with CHD under the dominant model. Further gender-based subgroup tests showed that one SNP (CD40 rs1800686) and two SNPs (FAM5C rs12732361 and CD36 rs2065666) were associated with CHD in females and males, respectively. And the age-based subgroup tests indicated that PLA2G7 rs9395208, IL1B rs16944, and CD40 rs1800686 were associated with CHD among individuals younger than 55, younger than 65, and over 65, respectively.

Conclusions

In conclusion, all the six inflammation-related CpG-SNPs (rs16944, rs2071008, rs12732361, rs2065666, rs9395208, and rs1800686) were associated with CHD in the combined or subgroup tests, suggesting an important role of inflammation in the risk of CHD.

Genetic susceptibility to prosthetic joint infection following total joint arthroplasty: A systematic review

BACKGROUND

Prosthetic joint infection (PJI) is the most common cause of total joint arthroplasty failure and revision surgery. Genetic polymorphisms could be determinant factors for PJI.

METHODS

We performed a systematic research of Medline, Pubmed, Embase, Cochrane Library, and Google Scholar, and identified 11 studies with 34 kinds of gene polymorphisms, were included in the synthesis.

RESULTS

Our data suggest that the C allele and genotype C/C for MBL-550 SNP, genotype A/A for MBL-54 SNP and G allele for MBL-221 SNP increase the risk of PJI, while G allele and genotype G/G for MBL-550 SNP decrease the risk of PJI in Caucasian populations. Several other genes reported by single-center studies also contribute to the genetic susceptibility to septic PJI. No definitive conclusions could be achieved due to the small amount of data in the included studies.

CONCLUSION

Several genes contribute to the genetic susceptibility to PJI following total joint arthroplasty. Further studies will enhance the understanding of PJI, and may inform and direct early interventions.

Antibacterial surface treatment for orthopaedic implants

It is expected that the projected increased usage of implantable devices in medicine will result in a natural rise in the number of infections related to these cases. Some patients are unable to autonomously prevent formation of biofilm on implant surfaces. Suppression of the local peri-implant immune response is an important contributory factor. Substantial avascular scar tissue encountered during revision joint replacement surgery places these cases at an especially high risk of periprosthetic joint infection. A critical pathogenic event in the process of biofilm formation is bacterial adhesion. Prevention of biomaterial-associated infections should be concurrently focused on at least two targets: inhibition of biofilm formation and minimizing local immune response suppression. Current knowledge of antimicrobial surface treatments suitable for prevention of prosthetic joint infection is reviewed. Several surface treatment modalities have been proposed. Minimizing bacterial adhesion, biofilm formation inhibition, and bactericidal approaches are discussed. The ultimate anti-infective surface should be “smart” and responsive to even the lowest bacterial load. While research in this field is promising, there appears to be a great discrepancy between proposed and clinically implemented strategies, and there is urgent need for translational science focusing on this topic.

The expanding horizon of prosthetic joint infections

Prosthetic joint infection (PJI) is a serious and potentially devastating complication of arthroplasty. Prior arthroplasty, immunosuppression, severe comorbid conditions, and prolonged surgical duration are important risk factors for PJI. More than half of the cases of PJI are caused by Staphylococcus aureus and coagulase-negative staphylococci. The biofilm plays a central role in its pathogenesis. The diagnosis of PJI requires the presence of purulence, sinus tract, evidence of inflammation on histopathology, or positive microbiologic cultures. The use of diagnostic imaging techniques is generally limited but may be helpful in selected cases. The most effective way to prevent PJI is to optimize the health of patients, using antibiotic prophylaxis in a proper and timely fashion. Management of PJI frequently requires removal of all hardware and administration of intravenous antibiotics. This review summarizes and analyzes the results of previous reports of PJI and assesses the prevention and management of this important entity.

Prosthetic joint infection

Prosthetic joint infection (PJI) is a tremendous burden for individual patients as well as the global health care industry. While a small minority of joint arthroplasties will become infected, appropriate recognition and management are critical to preserve or restore adequate function and prevent excess morbidity. In this review, we describe the reported risk factors for and clinical manifestations of PJI. We discuss the pathogenesis of PJI and the numerous microorganisms that can cause this devastating infection. The recently proposed consensus definitions of PJI and approaches to accurate diagnosis are reviewed in detail. An overview of the treatment and prevention of this challenging condition is provided.