Local and systemic chemokine patterns in a human musculoskeletal trauma model

Development of a predictive algorithm for patient survival after traumatic injury using a five analyte blood panel

Severe trauma can induce systemic inflammation but also immunosuppression, which makes understanding the immune response of trauma patients critical for therapeutic development and treatment approaches. By evaluating the levels of 59 proteins in the plasma of 50 healthy volunteers and 1000 trauma patients across five trauma centers in the United States, we identified 6 novel changes in immune proteins after traumatic injury and further new variations by sex, age, trauma type, comorbidities, and developed a new equation for prediction of patient survival. Blood was collected at the time of arrival at Level 1 trauma centers and patients were stratified based on trauma level, tissues injured, and injury types. Trauma patients had significantly upregulated proteins associated with immune activation (IL-23, MIP-5), immunosuppression (IL-10) and pleiotropic cytokines (IL-29, IL-6). A high ratio of IL-29 to IL-10 was identified as a new predictor of survival in less severe patients with ROC area of 0.933. Combining machine learning with statistical modeling we developed an equation ("VIPER") that could predict survival with ROC 0.966 in less severe patients and 0.8873 for all patients from a five analyte panel (IL-6, VEGF-A, IL-21, IL-29, and IL-10). Furthermore, we also identified three increased proteins (MIF, TRAIL, IL-29) and three decreased proteins (IL-7, TPO, IL-8) that were the most important in distinguishing a trauma blood profile. Biologic sex altered phenotype with IL-8 and MIF being lower in healthy women, but higher in female trauma patients when compared to male counterparts. This work identifies new responses to injury that may influence systemic immune dysfunction, serving as targets for therapeutics and immediate clinical benefit in identifying at-risk patients.

Increased extracellular ubiquitin in surgical wound fluid provides a chemotactic signal for myeloid dendritic cells

PURPOSE

Myeloid dendritic cells (MDC) decline significantly after multiple traumas which might be due to an increased migration into injured regions. Ubiquitin is released from dying cells and is increased in serum after trauma. Ubiquitin can bind to the chemokine receptor CXCR4. Thus, we hypothesized that elevated ubiquitin provides a chemotactic signal for MDC to injured regions.

METHODS

Surgical wound fluid (SWF) and serum from patients with mono-trauma (n = 20) were used to simulate the humoral situation in injured tissue. MDC were identified by flow cytometry. Chemotaxis was measured using transwell migration assays. Ubiquitin and CXCL12 (natural CXCR4 ligand) were determined by ELISA.

RESULTS

MDC express CXCR4 and fluorescence-labeled ubiquitin binds to MDC. Ubiquitin exerts a dose-dependent chemotactic effect (fourfold at 100 ng/mL, p < 0.05). Ubiquitin concentration was sixfold higher in SWF (p < 0.05), whereas CXCL12 was increased in serum. MDC migration towards SWF was significantly reduced (- 40%, p < 0.05), if ubiquitin was neutralized by specific antibodies.

CONCLUSIONS

Ubiquitin is increased in SWF and exerts a significant chemotactic effect on MDC. This mechanism might play a role in attraction of immune cells to injured regions and might contribute to the decline of circulating MDC in multiple traumas.

Inflammation and post-operative recovery in patients undergoing total knee arthroplasty-secondary analysis of a randomized controlled trial

OBJECTIVE

Reduced function persists for many patients after total knee arthroplasty (TKA). Inflammation is part of osteoarthritis' pathophysiology, and surgery induces a marked inflammatory response. We therefore wanted to explore the role of inflammation in long-term recovery after TKA, and thus conducted this secondary analysis of our randomized controlled trial (RCT) of physical rehabilitation ± progressive strength training (PST). We aimed to investigate whether (1) inflammation is associated with functional performance, knee-extension strength, and knee pain before TKA; (2) PST affects inflammation, and the inflammatory state over time; (3) baseline or surgery-induced inflammation modifies the effect of rehabilitation ± PST on change in 6-min walk test (Δ6MWT); and (4) baseline or surgery-induced inflammation is associated with Δ6MWT following TKA.

DESIGN

In the primary trial report's per-protocol analysis, 72/82 patients were included. Sixty had ≥1 blood sample before and after TKA, and were included in this secondary analysis. Inflammation was measured by interferon γ-inducible protein (IP)-10, soluble urokinase plasminogen activator receptor (suPAR), interleukin (IL)-6, IL-10, and tumor necrosis factor (TNF)-α at baseline; day 1, week 4, 8, and 26 after TKA.

RESULTS

At baseline, suPAR (P = 006) was negatively associated with 6MWT. Neither baseline nor surgery-induced inflammation modified the response to rehabilitation ± PST. Only surgery-induced IL-10 was associated with Δ6MWT_{26 weeks-baseline} (P = 0.001), also adjusted for 6MWT_baseline, age, sex and body mass index (BMI).

CONCLUSION

In this secondary analysis, only increased surgery-induced IL-10 response was associated with decreased long-term functional performance after TKA. The importance of controlling the surgery-induced immune response remains to be investigated further.

TRIAL IDENTIFICATION

NCT01351831.

Subsequent gene expression pattern in dendritic cells following multiple trauma

PURPOSE

Major trauma initiates a systemic inflammatory response, which is characterized by systemic release of various chemokines. There is growing evidence for the extraordinary role of dendritic cells (DC) as professional antigen-presenting cells and activators of the immune response. Recently, the impact of severe trauma on DC transcriptomic activation was demonstrated. The purpose of the present study was to evaluate gene expression pattern in DC following multiple trauma to gain further understanding of the mechanisms of posttraumatic immune response.

METHODS

Ten patients with multiple injuries aged 20 to 46 years (mean 30 ± 9.2 years) were included in this study. The mean injury severity score (ISS) was 36 ± 10.4 points. Repeated blood samples were taken on the day of admission (day 0) and on five consecutive days (day 1 to day 5). Microarray analysis and RT-qPCR were performed in primary isolated DC.

RESULTS

A mean of 116,000 ± 21,466 DC with a purity of 96 ± 0,8 % were harvested. Gene expression of CCL5 and CXCL5 as well as TIMP1 and GUCY1B3 showed a significant increase within the first 4 days after trauma. The time-dependent increase of these genes correlated significantly with serum CRP concentration and the total number of DC but neither with age nor with injury severity.

CONCLUSIONS

Our study provides new data regarding temporal expression patterns of CCL5, CXCL5, TIMP1, and GUCY13B in multiple trauma. DC activation following trauma may follow a uniform pattern early after admission, eventually leading to cell recruitment.