Plasma cytokines as markers of aseptic prosthesis loosening

CD73 inhibits titanium particle-associated aseptic loosening by alternating activation of macrophages

Aseptic inflammation is a major cause of late failure in total joint arthroplasty, and the primary factor contributing to the development and perpetuation of aseptic inflammation is classical macrophage activation (M1 phenotype polarization) induced by wear particles. CD73 (ecto-5'-nucleotidase) is an immunosuppressive factor that establishes an adenosine-induced anti-inflammatory environment. Although CD73 has been shown to suppress inflammation by promoting alternate macrophage activation (M2 phenotype polarization), its role in wear particle-induced aseptic inflammation is currently unknown. Our experiments were based on metabolomic assay results in a mouse model of aseptic loosening, and studied the function of CD73 in vivo and in vitro using a mouse aseptic loosening model and a mouse bone marrow derived macrophage (BMDM) inflammation model. Results show that aseptic loosening (AL) reduces the purine metabolic pathway and decreases the native expression of the metabolite adenosine. In vivo, CD73 expression was low in the bone tissue surrounding the titanium nail and synovial-like interface tissue, while in vitro experiments demonstrated that CD73 knockdown promoted titanium particles-induced aseptic inflammation. CD73 overexpression mitigated the titanium particle-mediated enhancement of LPS-induced M1 polarization while promoting the titanium particle-mediated attenuation of IL-4-induced M2 polarization. In BMDM exposed to titanium particles, CD73 promotes M2 polarization via the p38 pathway. Meanwhile, local injection of recombinant mouse CD73 protein slightly alleviated the progression of AL. Collectively, our data suggest that CD73 alleviates the process of AL, and this function is achieved by promoting alternate activation of macrophages.

Assessment of the systemic immune response in patients with inflammatory complications of large joint implants

One of the most common reasons for the progressing of aseptic instability of implanted structures in patients with end-stage osteoarthrosis is a disorder of immunogenulatory processes of bone tissue remodeling along with chronic inflammatory response influenced by endoprosthesis wear components. This research features the specifics of systemic immune response in patients with inflammatory complications in late postoperative period after total replacements of large joints. The factor analysis enabled determining the most significant immunological mechanisms associated with the progressing of implant aseptic instability. Pathogenetically significant components involved in the formation of cellular and humoral immune responses in patients with signs of inflammatory activity in late postoperative period have been identified. Our findings can be used in designing diagnostic and prognostic criteria for systemic inflammatory response severity in preoperative monitoring of the condition of patients in need of large joint arthroplasties, and also in detecting the progress of implant aseptic instability.

Effect of Alumina Particles on the Osteogenic Ability of Osteoblasts

Biomaterials are used as implants for bone and dental disabilities. However, wear particles from the implants cause osteolysis following total joint arthroplasty (TJA). Ceramic implants are considered safe and elicit a minimal response to cause periprosthetic osteolysis. However, few reports have highlighted the adverse effect of ceramic particles such as alumina (Al2O3) on various cell types. Hence, we aimed to investigate the effect of Al2O3 particles on osteoprogenitors. A comparative treatment of Al2O3, Ti, and UHMWPE particles to osteoprogenitors at a similar concentration of 200 μg/mL showed that only Al2O3 particles were able to suppress the early and late differentiation markers of osteoprogenitors, including collagen synthesis, alkaline phosphatase (ALP) activity and mRNA expression of Runx2, OSX, Col1α, and OCN. Al2O3 particles even induced inflammation and activated the NFkB signaling pathway in osteoprogenitors. Moreover, bone-forming signals such as the WNT/β-catenin signaling pathway were inhibited by the Al2O3 particles. Al2O3 particles were found to induce the mRNA expression of WNT/β-catenin signaling antagonists such as DKK2, WIF, and sFRP1 several times in osteoprogenitors. Taken together, this study highlights a mechanistic view of the effect of Al2O3 particles on osteoprogenitors and suggests therapeutic targets such as NFĸB and WNT signaling pathways for ceramic particle-induced osteolysis.

Wear of hip prostheses increases serum IGFBP-1 levels in patients with aseptic loosening

The biological mechanisms involved in aseptic loosening include inflammation-associated and bone resorption-associated processes. Coordinated cellular actions result in biochemical imbalances with devastating consequences for the joint. Given that this condition is not known for showing systemic signs, we investigated whether circulating levels of inflammation-related proteins are altered in patients with aseptic loosening. Our study included 37 patients who underwent revision surgery due to hip osteolysis and aseptic loosening and 31 patients who underwent primary total hip arthroplasty. Using antibody arrays, we evaluated the serum levels of 320 proteins in four patients from each group. The results showed differences in insulin-like growth factor-binding protein 1 (IGFBP-1) concentrations, which we then quantified using enzyme-linked immunosorbent assay tests in all study patients. The results confirmed that serum IGFBP-1 concentrations were higher in the revision surgery patients than in the hip arthroplasty patients. In vitro studies showed that exposure of human osteoblasts to titanium particles induced an IGFBP-1 release that further increased when exposure to particles was performed in media conditioned by human M1 macrophages. These findings suggest that elevated serum IGFBP-1 levels in patients with aseptic loosening can arise from increased local IGFBP-1 production in the inflammatory environment of the periprosthetic bed.

Damage control orthopaedics in polytraumatized patients- current concepts

The principles of fracture management in patients with multiple injuries continue to be of crucial importance. Early treatment of unstable polytraumatized patients with head, chest, abdomen or pelvic injuries, with blood loss followed by immediate fracture fixation (Early Total Care -ETC) may be associated with secondary life threatening posttraumatic systemic inflammatory response syndrome (SIRS). Development of SIRS is typically a function of the type and severity of the initial injury (the "first hit"). Immediate Fracture fixation, using reamed nails or plates, in such unstable patients with multiple injuries is subsequently defined as the "second hit" and may be associated with development of acute respiratory distress syndrome (ARDS) and multiple organ failure (MOF), with relatively high morbidity and mortality. The other alternative for long bone fracture fixation in unstable polytraumatized patients is based on immediate treatment of life threatening conditions related to the injuries, followed by the initial use of minimally invasive modular external frames for long bone fractures and is called Damage Control Orthopedics (DCO) and is widely accepted. In order to refine the DCO concept and to avoid an overuse of external fixation, the "Safe Definitive Surgery" (SDS) concept has been introduced, which is a dynamic synthesis of both strategies (ETC and DCO). The SDS strategy employs clinical parameters and includes repeated assessment of patients. The following paper is going to summarize historical backgrounds and recent concepts in treatment of polytraumatized patients.

The effect of TNF-α on osteoblasts in metal wear-induced periprosthetic bone loss

Aims

This study aimed to examine the effects of tumour necrosis factor-alpha (TNF-α) on osteoblasts in metal wear-induced bone loss.

Methods

TNF-α immunoexpression was examined in periprosthetic tissues of patients with failed metal-on-metal hip arthroplasties and also in myeloid MM6 cells after treatment with cobalt ions. Viability and function of human osteoblast-like SaOs-2 cells treated with recombinant TNF-α were studied by immunofluorescence, terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling (TUNEL) assay, western blotting, and enzyme-linked immunosorbent assay (ELISA).

Results

Macrophages, lymphocytes, and endothelial cells displayed strong TNF-α immunoexpression in periprosthetic tissues containing metal wear debris. Colocalization of TNF-α with the macrophage marker CD68 and the pan-T cell marker CD3 confirmed TNF-α expression in these cells. Cobalt-treated MM6 cells secreted more TNF-α than control cells, reflecting the role of metal wear products in activating the TNF-α pathway in the myeloid cells. While TNF-α did not alter the immunoexpression of the TNF-receptor 1 (TNF-R1) in SaOs-2 cells, it increased the release of the soluble TNF-receptor 1 (sTNF-R1). There was also evidence for TNF-α-induced apoptosis. TNF-α further elicited the expression of the endoplasmic reticulum stress markers inositol-requiring enzyme (IRE)-1α, binding-immunoglobulin protein (BiP), and endoplasmic oxidoreductin1 (Ero1)-Lα. In addition, TNF-α decreased pro-collagen I α 1 secretion without diminishing its synthesis. TNF-α also induced an inflammatory response in SaOs-2 cells, as evidenced by the release of reactive oxygen and nitrogen species and the proinflammatory cytokine vascular endothelial growth factor.

Conclusion

The results suggest a novel osteoblastic mechanism, which could be mediated by TNF-α and may be involved in metal wear debris-induced periprosthetic bone loss.

Cite this article: Bone Joint Res 2020;9(11):827–839.

Platelet-derived growth factor-BB attenuates titanium-particle-induced osteolysis in vivo

Inflammation and osteoclastogenesis play critical roles in wear-particle-induced periprosthetic osteolysis (WPO). Platelet-derived growth factor-BB (PDGF-BB) could promote osteogenesis and inhibit inflammatory response. The aim of this study was to investigate the impact of PDGF-BB on WPO. Mice were divided into four groups, namely, sham, vehicle, low-, and high-dose PDGF-BB groups. Mice in the rhPDGF-BB groups were treated with PDGF-BB at 0.25 or 1 mg/ml/kg/day. Mice in the sham and vehicle groups received PBS daily. Two weeks after surgery, calvariae were harvested. Immunohistochemical analysis and μ-CT showed that PDGF-BB significantly reduced osteoclast formation and bone resorption. ELISA showed that rhPDGF-BB decreased the secretion of TNF-α, IL-1β, and IL-6. Western blotting revealed that rhPDGF-BB stimulated the expression of osteocalcin and osteoprotegerin. Furthermore, more VEGF and CD31 proteins were observed due to PDGF-BB by immunofluorescence. In conclusion, these findings suggest that rhPDGF-BB represents a potential treatment for WPO.

Are there biological markers for wear or corrosion? A systematic review

BACKGROUND

Identification of biomarkers associated with wear and tribocorrosion in joint arthroplasty would be helpful to enhance early detection of aseptic loosening and/or osteolysis and to improve understanding of disease progression. There have been several new reports since the last systematic review (which covered research through mid-2008) justifying a new assessment.

QUESTIONS/PURPOSES

We sought to determine which biomarkers have the most promise for early diagnosis and monitoring of aseptic loosening and/or osteolysis related to wear or corrosion in total joint arthroplasty.

METHODS

We performed a systematic review using MEDLINE and EMBASE databases, covering the period through December 2013, and identified 1050 articles. We restricted the definition of biomarker to biomolecules and imaging parameters useful for diagnosis and monitoring of disease progression, only including articles in English. We chose 65 articles for full review, including 44 from the original search and 21 from subsequent hand searches. We used the 22 articles in which patients with total joint arthroplasty who had aseptic loosening and/or periimplant osteolysis unrelated to sepsis had been compared with patients with total joint arthroplasty with stable implants. There were 90 comparisons of these two patient populations involving 35 different biomarkers.

RESULTS

Diagnostic accuracy was assessed in nine of the 90 comparisons with the highest accuracy found for tartrate-resistant acid phosphatase 5b (0.96), although a separate comparison for this biomarker found a lower accuracy (0.76). Accuracy of > 0.80 was also found for crosslinked n-telopeptide of type I collagen, osteoprotegerin, and deoxypyridinoline. The most studied markers, tumor necrosis factor-α and interleukin-1β, were found to differ in the affected and control groups in < 30% of the comparisons. Thirty of the 35 biomarkers were studied in four or fewer separate comparisons with nearly half of the biomarkers (17) studied in only one comparison. Many of the comparisons were not able to eliminate a number of confounding variables, and there was only one prospective study.

CONCLUSIONS

Currently, there are no validated biomarkers for early diagnosis and monitoring of the biological sequelae of wear or tribocorrosion, although there are some promising leads, including markers of bone turnover.

Lipopolysaccharide-binding protein: a valuable biomarker in the differentiation between periprosthetic joint infection and aseptic loosening?

PURPOSE

The pre-operative differentiation between periprosthetic joint infection (PJI) and aseptic loosening after total hip (THA) or knee (TKA) arthroplasty is essential for successful therapy and relies in part on the use of molecular markers. The objective of this study was to assess serum levels of lipopolysaccharide-binding protein (LBP) as a diagnostic tool for PJI and to compare its accuracy with standard tests.

METHODS

One hundred and twenty patients presenting with a painful TKA or TKA with indication for surgical revision were included in this prospective, controlled, clinical trial at a single centre. Pre-operative blood and serum samples were collected and analysed for white blood cell (WBC) count, C-reactive protein (CRP) and LBP. The definite diagnosis of periprosthetic joint infection was determined on the basis of clinical, microbiological and histopathological examination.

RESULTS

LBP showed significantly higher values in PJI compared with aseptic loosening (p < 0.001) and control (p < 0.001), with a specificity of 66% and a sensitivity of 71% at a cutoff value of >7 ng/ml. In combination with CRP, the positive predictive value for PJI was at 0.67; negative predictive value with both negative was at 0.77.

DISCUSSION

Patients with PJI have elevated serum levels of LBP when compared with patients with aseptic loosening. The use of LBP in serum appears not to be a more accurate marker than CRP level in serum for detecting PJI. On the basis of these results, we cannot recommend the sole use of LBP for differentiating PJI and aseptic loosening following THA and TKA.

Cytokine levels (IL-4, IL-6, IL-8 and TGFβ) as potential biomarkers of systemic inflammatory response in trauma patients

PURPOSE

Much research is now being conducted in order to understand the role of cytokines in the development of the inflammatory response following trauma. The purpose of this study was to evaluate whether serum levels of certain cytokines, measured immediately after initial injury, can be used as potential biomarkers for predicting the development and the degree of severity of the systemic inflammatory response (SIRS) in patients with moderate and severe trauma.

METHODS

We conducted a prospective study with 71 individuals of whom 13 (18.3 %) were healthy controls and 58 (81.7 %) were traumatized orthopaedic patients who were categorized into two groups: 31 (43.6 %) with moderate injuries and 27 (38.1 %) patients with severe orthopaedic trauma. Thirty cc of heparinized blood were drawn from each individual within a few hours after the injury. Serum levels of pro-inflammatory, regulatory and anti-inflammatory cytokines were measured in each individual participant.

RESULTS

High levels of pro-inflammatory cytokines IL-1β,-6,-8,-12, tumour necrosis factor alpha and interferon gamma were found in all injured patients compared to healthy controls. Only IL-6 and IL-8 were significantly higher in the injured patients. Levels of the regulatory cytokines, transformed growth factor beta (TGF-β) and IL-10 were higher in the injured patients, but significant only for TGF-β. Levels of IL-4 were significantly lower in the injured groups as compared to the controls.

CONCLUSIONS

Secretion of large amounts of pro-inflammatory cytokines and decreased level of anti-inflammatory cytokines during the acute phase of trauma may lead to the development of systemic inflammatory response syndrome (SIRS) in unstable polytraumatized patients. SIRS may result in life threatening conditions as acute respiratory distress syndrome (ARDS) and multiple organ failure (MOF). High levels of IL-6, IL-8, TGFβ and low levels of IL-4 were found to be reliable markers for the existence of immune reactivity in trauma patients. More research is needed to study pattern of cytokine levels along the acute period of injury, after surgical interventions and during recovery.

Titanium particle-challenged osteoblasts promote osteoclastogenesis and osteolysis in a murine model of periprosthestic osteolysis

The current study investigates the interactive behavior of titanium alloy particle-challenged osteoblastic bone marrow stromal cells (BMSCs) and macrophage lineage cells in a murine knee-prosthesis failure model. BMSCs were isolated from male BALB/c mice femurs and induced in osteogenic medium. At 24h after isolation, BMSCs in complete induction medium were challenged with 1, 3 or 5mgml(-1) titanium particles for 7days. Culture media were collected at 2, 4 and 6days and cells were harvested at 7days for alkaline phosphatase (ALP) assay/stains. Cell proliferation in the presence of Ti particles was periodically evaluated by MTT assay. Mice implanted with titanium-pin tibial implants were given an intra-articular injection of 50μl medium containing 5×10(5) Ti particles-challenged bone-marrow-derived osteoblastic cells, followed by a repeat injection at 2weeks post-operation. Control mice with titanium-pin implants received a naïve osteoblastic cell transfusion. After sacrifice at 4weeks, the implanted knee joint of each group was collected for biomechanical pin-pullout testing, histological evaluation and reverse transcriptase polymerase chain reaction analysis of mRNA extracted from the joint tissues. Ti particles significantly stimulated the proliferation of BMSC-derived osteoblastic cells at both high and low particle concentrations (p<0.05), with no marked differences between the particle doses. ALP expression was diminished following Ti particle interactions, especially in the high-dose particle group (p<0.05). In addition, the culture media collected from short-term challenged (48h) osteoblasts significantly increased the numbers of TRAP+ cells when added to mouse peripheral blood monocytes cultures, in comparison with the monocytes cells receiving naïve osteoblasts media (p<0.05). Intra-articular introduction of the osteoblastic cells to the mouse pin-implant failure model resulted in reduced implant interfacial shear strength and thicker peri-implant soft-tissue formation, suggesting that titanium particles-challenged osteoblasts contributed to periprosthetic osteolysis. Comparison of the gene expression profiles among the peri-implant tissue samples following osteoblast injection did not find significant difference in RunX2 or Osterix/Sp7 between the groups. However, MMP-2, IL-1, TNF-α, RANKL, and TRAP gene expressions were elevated in the challenged-osteoblast group (p<0.05). In conclusion, titanium alloy particles were shown to interfere with the growth, maturation, and functions of the bone marrow osteoblast progenitor cells. Particle-challenged osteoblasts appear to express mediators that regulate osteoclastogenesis and peri-prosthetic osteolysis.

Multiple biomarkers analysis for the early detection of prosthetic aseptic loosening of hip arthroplasty

PURPOSE

Our aim was to define the effect of multiple biomarkers of osteolysis or bone remodelling in the early detection of aseptic loosening (AL) of total hip arthroplasty (THA).

METHOD

One hundred subjects were recruited, including 31 candidates for revision THA (Late AL group), 15 patients who had undergone THA and had clinical and radiographic evidence of AL (early AL group), 19 patients with no sign of AL (stable group), and 40 healthy volunteers. Plasma levels of osteoprotegerin (OPG), receptor activator of nuclear factor-kappaB ligand (RANKL), cross-linked N-terminal telopeptide (NTX), procollagen I C-terminal extension peptide (PICP), tumour necrosis factor-alpha (TNF-α), and interleukin (IL)-1β1 were measured using an immunoenzymatic method. The outcomes of biomarkers were analysed separately and synthetically using Revman software.

RESULTS

The plasma level of OPG, RANKL, NTX, TNF-α, and IL-1β declined from late AL, early AL, stable to the healthy group, while the level of PICP inclined reversely. There was a significant difference in synthetic analysis of six biomarkers between the AL group and the stable group, and between the stable group and the healthy group (both p = 0.02). Heterogeneity of six biomarkers in either comparison was extremely low (both I(2) =0). Patients who had cemented implants had significantly higher levels of TNF-α than patients with cementless varieties (p = 0.042).

CONCLUSION

There was significant change in the plasma level of multiple biomarkers in patients with prosthetic AL of THA, especially in the cemented arthroplasties and in patients without traditional clinical or radiographic evidence of AL.

Effects of Ti, PMMA, UHMWPE, and Co-Cr wear particles on differentiation and functions of bone marrow stromal cells

This study investigates the roles of orthopedic biomaterial particles [Ti-alloy, poly(methyl methacrylate) (PMMA), ultrahigh-molecular-weight polyethylene (UHMWPE), Co-Cr alloy] on the differentiation and functions of bone marrow stromal cells (BMSCs). Cells were isolated from femurs of BALB/c mice and cultured in complete osteoblast-induction medium in presence of micron-sized biomaterial particles at various doses. 3-(4,5)-Dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay and lactate dehydrogenase assay were performed for cell proliferation and cytotoxicity. Differentiation and function of osteoblasts were evaluated by alkaline phosphatase (ALP), osteocalcin, RANKL, OSX, and Runx2 expressions. Murine interleukin-1 (IL-1), IL-6, and tumor necrosis factor-α in culture media were determined by enzyme-linked immunosorbent assay. Challenge with low doses of Ti, UHMWPE, or Co-Cr particles markedly promoted the bone marrow cell proliferation while high dose of Co-Cr significantly inhibited cell growth (p < 0.05). Cells challenged with low dose of PMMA or UHMWPE particles (0.63 mg/mL) exhibited strong ALP activity, whereas Ti and Co-Cr groups showed minimal effects (p < 0.05). UHMWPE and Ti particles also promoted higher expression of proinflammatory cytokines. Real-time polymerase chain reaction data suggested that cells treated with low dose (0.5 mg/mL) particles resulted in distinctly diminished RANKL expression compared to those exposed to high concentrated (3 mg/mL) particles. In conclusion, various types of wear debris particles behaved differently in the differentiation, maturation, and functions of osteogenic cells; and the particulate debris-interacted BMSCs may play an important role in the pathogenesis and process of the debris-associated aseptic prosthetic loosening.

Biological responses of human mesenchymal stem cells to titanium wear debris particles

Wear debris-induced osteolysis is a major cause of orthopedic implant aseptic loosening, and various cell types, including macrophages, monocytes, osteoblasts, and osteoclasts, are involved. We recently showed that mesenchymal stem/osteoprogenitor cells (MSCs) are another target, and that endocytosis of titanium (Ti) particles causes reduced MSC proliferation and osteogenic differentiation. Here we investigated the mechanistic aspects of the endocytosis-mediated responses of MSCs to Ti particulates. Dose-dependent effects were observed on cell viability, with doses >300 Ti particles/cell resulting in drastic cell death. To maintain cell viability and analyze particle-induced effects, doses <300 particles/cell were used. Increased production of interleukin-8 (IL-8), but not IL-6, was observed in treated MSCs, while levels of TGF-β, IL-1β, and TNF-α were undetectable in treated or control cells, suggesting MSCs as a likely major producer of IL-8 in the periprosthetic zone. Disruptions in cytoskeletal and adherens junction organization were also observed in Ti particles-treated MSCs. However, neither IL-8 and IL-6 treatment nor conditioned medium from Ti particle-treated MSCs failed to affect MSC osteogenic differentiation. Among other Ti particle-induced cytokines, only GM-CSF appeared to mimic the effects of reduced cell viability and osteogenesis. Taken together, these results strongly suggest that MSCs play both responder and initiator roles in mediating the osteolytic effects of the presence of wear debris particles in periprosthetic zones.

Biomarkers in arthroplasty: a systematic review

We performed a systematic review of all MEDLINE-published studies of biomarkers in arthroplasty. Thirty studies met the inclusion criteria; majority evaluated biomarkers for osteolysis, aseptic prosthetic loosening, and prosthetic infections. Four studies reported an elevated Cross-linked N-telopeptides of type I collagen (urine or serum) in patients with osteolysis or aseptic prosthetic loosening when compared to appropriate controls. Two or more studies each found elevated C-reactive protein, erythrocyte sedimentation rate, and interleukin-6 in patients with infected prosthetic joints compared to controls. Most other biomarkers were either examined by single studies or had inconsistent or insignificant associations with outcomes. We conclude that the majority of the biomarkers currently lack the evidence to be considered as biomarkers for arthroplasty outcomes. Further studies are needed.

Elevated levels of numerous cytokines in drainage fluid after primary total hip arthroplasty

As cytokines are involved in wound healing and other inflammatory processes, it could be valuable to measure their levels at the operative site. This study was conducted to investigate whether different cytokines are measurable in drainage fluid and, when measurable, whether we can find a difference in cytokine levels between one and six hours postoperatively. Samples from the drainage system in 30 consecutive patients undergoing primary total hip replacement were collected at one and six hours after closure of the wound. Levels of several cytokines were measured in the drainage fluids. A significant elevation of almost all cytokines was observed between the sample after one hour and six hours postoperatively. We found a strong correlation between the different pro-inflammatory cytokines. The IL-6 to IL-10 ratio were also raised, showing a pro-inflammatory predominance. Levels were much higher than those previously shown in serum.

Effect of oral erythromycin therapy in patients with aseptic loosening of joint prostheses

There is currently no cure for aseptic loosening (AL) of total joint replacement (TJR) except surgical revision. The purpose of this study was to determine whether oral EM could improve the periprosthetic tissue profiles and reduce serum cytokine production in AL patients who are candidates for surgical revision. We recruited 32 AL patients. AL patients were treated with either EM (600 mg/day, n=18) or placebo (n=14) daily, started one month before surgery and ending on the day of surgery. Blood samples were obtained before EM treatment and during surgery. Periprosthetic tissues and joint fluids were collected during surgery. Our results demonstrate that oral EM reduces the inflammation of periprosthetic tissues, as manifested by the reduction of the numbers of infiltrating cells, CD68+ macrophages, RANKL+ cells, and TRAP+ cells. Remarkable decreases of TNFalpha (9.6-fold), IL-1beta (21.2-fold), and RANKL (76-fold) gene transcripts were observed in periprosthetic tissues of patients treated with oral EM. Serum levels of both TNFalpha and (to a lesser extent) IL-1beta were significantly reduced following EM treatment (p<0.05). Our results suggest that EM represents a biological cure or prevention for those patients who might need repeated revision surgeries and/or show the early signs of progressive osteolysis after TJR.

Expansion of CD14+CD16+ peripheral monocytes among patients with aseptic loosening

OBJECTIVE AND DESIGN

In this study, we have investigated the relevance of peripheral blood inflammatory CD14(+)CD16(+) monocytes phenotype to patients with aseptic loosening (AL).

MATERIAL AND TREATMENT

Immunophenotypes of monocytes were examined among patients with AL (n = 43), patients with mechanical loosening (ML, n = 30), patients with stable implant (SI, n = 16), and patients with osteoarthritis (OA, n = 17) using flow cytometry.

METHODS

Immunological assay was used to measure TNF-alpha and IL-1 beta levels in both sera and culture media of implant wear stimulated CD14(+)CD16(+) and CD14(++)CD16(-) monocytes. Periprosthetic tissues were collected during surgery for histological assessment.

RESULTS

The frequency of CD14(+)CD16(+) monocytes showed significant increase in AL patients than in ML, SI, and OA patients. A positive association was found between the subpopulation of CD14(+)CD16(+) monocytes and plasma TNF-alpha and IL-1 beta level in AL patients. Furthermore, a positive correlation existed between the subpopulation of CD14(+)CD16(+) monocytes and the total histopathology score.

CONCLUSION

The results indicate that CD14(+)CD16(+) monocytes represent a sensitive marker for the disease activity of AL, and may serve as an effective prognostic index to identify total joint replacement recipients who are at increased risk for osteolysis and progression of AL.

Correlation between synovial fluid and serum IL-1beta levels after ACL surgery-preliminary report

The possibility of controlling the harmful intra-articular influence of elevated interleukin (IL)-1beta synovial fluid concentration after anterior cruciate ligament (ACL) surgery could be useful. We investigated the correlation between serum and synovial fluid IL-1beta levels following ACL reconstruction. We measured IL-1beta concentration periodically in three synovial fluid and four serum samples in each of 20 patients receiving either autologous conditioned serum (ACS) containing endogenous anti-inflammatory cytokines including IL-1Ra and several growth factors (group A) or placebo (group B). A decrease in IL-1beta synovial fluid concentration appeared to be more pronounced in absolute terms in group A. In eight patients serum IL-1beta was detected on the 6th postoperative day. In four of them whose synovial fluid levels were over 10 pg/ml on the 6th postoperative day, serum IL-1beta was detected on the 10th postoperative day. The results were different in group B. Correlation between serum and synovial fluid IL-1beta appearance persists in patients after ACL surgery and ACS application. This study is an example of ACS influence on the ACL healing process controlling the IL-1beta levels on the basis of the serum IL-1beta detection.

Expression profiling reveals alternative macrophage activation and impaired osteogenesis in periprosthetic osteolysis

Interactions between periprosthetic cells and prosthetic wear debris have been recognized as an important event in the development of osteolysis and aseptic loosening. Although the ability of wear debris to activate pro-inflammatory macrophage signaling has been documented, the full repertoire of macrophage responses to wear particles has not been established. Here, we examined the involvement of alternative macrophage activation and defective osteogenic signaling in osteolysis. Using real-time RT-PCR analysis of periprosthetic soft tissue from osteolysis patients, we detected elevated levels of expression of alternative macrophage activation markers (CHIT1, CCL18), chemokines (IL8, MIP1 alpha) and markers of osteoclast precursor cell differentiation and multinucleation (Cathepsin K, TRAP, DC-STAMP) relative to osteoarthritis controls. The presence of cathepsin K positive multinuclear cells was confirmed by immunohistochemistry. Reduced expression levels of the osteogenic signaling components BMP4 and FGF18 were detected. Expression levels of TNF-alpha, IL-6, and RANKL were unchanged, while the anti-osteoclastogenic cytokine OPG was reduced in osteolysis patients, resulting in elevated RANKL:OPG ratios. In vitro studies confirmed the role of particulate debris in alternative macrophage activation and inhibition of osteogenic signaling. Taken together, these results suggest involvement in osteolysis of alternative macrophage activation, accompanied by elevated levels of various chemokines. Increased recruitment and maturation of osteoclast precursors is also observed, as is reduced osteogenesis. These findings provide new insights into the molecular pathogenesis of osteolysis, and identify new potential candidate markers for disease progression and therapeutic targeting.