OP0301 RISK FACTORS FOR ANTI-INFLIXIMAB ANTIBODY FORMATION: RESULTS FROM THE RANDOMISED CONTROLLED NOR-DRUM A TRIAL

Background:

Immunogenicity is related to loss of efficacy and safety to TNFα inhibitors and is frequently observed early in the treatment course. The highest rate of anti-drug antibody (ADAb) formation has been reported for infliximab (IFX). 1 Knowledge about risk factors for immunogenicity might contribute to better handling of this problem in clinical practice.

Objectives:

To identify risk factors for ADAb formation during the early phase of IFX treatment.

Methods:

411 patients with immune-mediated inflammatory diseases (84 rheumatoid arthritis (RA), 119 spondyloarthritis (SpA), 45 psoriatic arthritis, 83 ulcerative colitis, 58 Crohn’s disease and 22 psoriasis) initiating IFX treatment were included in the 38-week NOR-DRUM A trial and randomised 1:1 to therapeutic drug monitoring or standard IFX therapy.2 The primary endpoint was clinical remission at week 30. Serum (s) IFX levels and ADAb were measured at each infusion by in-house assays; time-resolved fluorometric assay for sIFX and inhibition assay for ADAb.2 In this sub-study, possible risk factors for ADAb formation including demographic variables, diagnosis, comedication, disease activity, IFX dose, sIFX and drug holidays, were assessed using logistic regression. Variables with a p-value <0.25 in univariate analyses were further examined in multivariate analyses adjusting for potential confounders (diagnosis, disease activity, age and gender).

Results:

410 of 411 patients had at least one measurement of sIFX and were included in the present analyses. 76% of patients were biologic-naive and 45% (18% of RA patients) used IFX as monotherapy. Patients received a mean IFX dose of 3.2-5.9 mg/kg (RA 3.2 mg/kg). ADAb were detected in 78 (19%) patients. The Table 1 shows variables with a significant association to ADAb development. Analyses revealed an increased risk of ADAb development in patients with RA (Odds ratio (OR) 2.1, 95% confidence interval (CI) 1.1-3.9), while SpA had a lower risk (OR 0.5, CI 0.2-0.9) compared to the other diagnoses. These findings were consistent in both univariate- and multivariate analyses (Table 1). Figure 1 shows the cumulative hazard for ADAb development according to diagnosis. Other risk factors for ADAb (Table 1) were smoking (OR 1.8, CI 1.0-3.3) and drug holidays of more than 12 weeks (OR 4.7, CI 1.2-18.3). Additionally, the risk of ADAb increased with higher disease activity (OR 1.5, CI 1.0-2.3) and lower sIFX levels (0.7, 0.6-0.8). Patients co-treated with methotrexate (OR 0.4, CI 0.2-0.9) or thiopurines (OR 0.3, CI 0.1-0.8), or having one or more IFX dose increments (OR 0.4, CI 0.3-0.8), had a reduced risk of immunogenicity.

Table 1.

Risk factors for ADAb. Results from logistic regression analyses

Univariate analysesMultivariate analyses (Adjusted for diagnosis, disease activity, age and gender)ORCIORCIRA2.2**[1.3,3.8]2.1*[1.1,3.9]SpA0.4**[0.2,0.8]0.5*[0.2,0.9]Methotrexate1.1[0.7,1.9]0.4*[0.2,0.9]Thiopurine0.3*[0.1,0.9]0.3*[0.1,0.8]Current or former smoking2.2**[1.3,3.8]1.8*[1.0,3.3]Mean sIFX0.7***[0.6,0.8]0.7***[0.6,0.8]>12 weeks between infusions4.5*[1.3,16.0]4.7*[1.2,18.3]IFX dose increment0.5*[0.3,0.9]0.4**[0.3,0.8]Mean DAS28 (RA and PsA)1.5*[1.0,2.1]1.5*[1.0,2.3]Mean ESR1.1***[1.0,1.1]1.1***[1.0,1.1]Mean CRP1.1**[1.0,1.1]1.1**[1.0,1.1]

* p<0.05, ** p<0.01, *** p<0.001

Only variables with a p-value <0.05 are shown. Non-significant variables include other demographic variables and IFX dose.

Conclusion:

This study identified smoking, drug holidays, high disease activity, IFX monotherapy and low sIFX levels as risk factors for ADAb development. Of particular interest, we found that RA patients had significantly increased risk of ADAb compared to the other immune-mediated inflammatory diseases. Whether this novel finding reflects different underlying disease mechanisms or the fact that RA patients receive a lower IFX dose, is not known and needs to be further explored.

References:

[1]Thomas SS et al. BioDrugs 2015;29(4):241-58 2 Syversen SW et al. Trials 2020 6;21(1):13

Disclosure of Interests:

Marthe Kirksæther Brun: None declared, Guro Løvik Goll Speakers bureau: Pfizer, AbbVie, Boehringer Ingelheim, Roche, Orion pharma, Sandoz and Novartis, Kristin Kaasen Jørgensen Speakers bureau: Celltrion, AOP Orphan Pharmaceuticals and Norgine, Joe Sexton: None declared, Johanna Elin Gehin Speakers bureau: Roche, Øystein Sandanger: None declared, Inge Olsen: None declared, Rolf Anton Klaasen: None declared, David J Warren: None declared, Cato Mørk Speakers bureau: Novartis Norge AS, LEO Pharma AS, ACO Hud Norge AS, Cellgene AS, Abbvie, Galderma Nordic and UCB, Tore K. Kvien Speakers bureau: TAmgen, Celltrion, Egis, Evapharma, Ewopharma, Hikma, Oktal, Sandoz and Sanofi, Consultant of: AbbVie, Amgen, Biogen, Celltrion, Eli Lilly, Gilead, Mylan, Novartis, Pfizer, Sandoz and Sanofi, Grant/research support from: Research funding to Diakonhjemmet Hospital from AbbVie, Amgen, BMS, MSD, Pfizer and UCB, Jørgen Jahnsen: None declared, Nils Bolstad Speakers bureau: Roche Pharmaceuticals and Novartis, Consultant of: Janssen, Espen A Haavardsholm Speakers bureau: Pfizer, AbbVie, Celgene, Novartis, Janssen, Gilead, Eli-Lilly and UCB, Silje Watterdal Syversen Speakers bureau: Thermo Fisher.

OP0018 A MULTICENTER RANDOMIZED STUDY IN EARLY RHEUMATOID ARTHRITIS TO COMPARE ACTIVE CONVENTIONAL THERAPY VERSUS THREE BIOLOGICAL TREATMENTS: 24 WEEK EFFICACY RESULTS OF THE NORD-STAR TRIAL

Background:

The optimal first-line treatment of patients (pts) with early rheumatoid arthritis (RA) is yet to be established.

Objectives:

The primary aim was to assess and compare the proportion of pts who achieved remission with active conventional therapy (ACT) and with three different biologic therapies after 24 wks. Secondary aims were to assess and compare other efficacy measures.

Methods:

The investigator-initiated NORD-STAR trial (NCT01491815) was conducted in the Nordic countries and Netherlands. In this multicenter, randomized, open-label, blinded-assessor study pts with treatment-naïve, early RA with DAS28>3.2, and positive RF or ACPA, or CRP >10mg/L were randomized 1:1:1:1. Methotrexate (25 mg/week after one month) was combined with: 1) (ACT): oral prednisolone (tapered quickly);or: sulphasalazine, hydroxychloroquine and mandatory intra-articular (IA) glucocorticoid (GC) injections in swollen joints <wk 20; 2) certolizumab 200 mg EOW SC (CZP); 3) abatacept 125 mg/wk SC (ABA); tocilizumab 162 mg/wk SC (TCZ). IA GC was allowed in all arms <wk 20. Primary outcome was clinical disease activity index remission (CDAI≤2.8) at wk 24. Secondary outcomes included CDAI remission over time and other remission criteria. Dichotomous outcomes were analyzed by adjusted logistic regression with non-responder imputation (NRI). Non-inferiority analyses had a pre-specified margin of 15%.

Results:

812 pts were randomized. Age was 54.3±14.7 yrs (mean±SD), 31.2% were male, DAS28 5.0±1.1, 74.9% were RF and 81.9% ACPA positive. Fig 1 shows the adjusted CDAI remission rates over time with 95% CI. Table shows crude remission and response rates and absolute differences in adjusted remission and response rates (superiority analysis). Differences in remission and response rates with CZP and TCZ, but not with ABA, remained within the pre-defined non-inferiority margin versus ACT, Fig 2.

Figure 1.

CDAI remission over time (adj. estimates with 95% CI)

Figure 2.

Non-inferiority analysis of protocol population. Estimated differences in CDAI remission rates between Arm 1 (active conventional therapy) and Arms 2, 3, and 4 (biologic arms) as reference with 95% confidence intervals, adjusted for gender, ACPA status, country, age, body-mass index and baseline DAS28-CRP. ABA, abatacept; CZP, certolizumab-pegol; MTX, methotrexate; TCZ, tocilizumab.

Conclusion:

High remission rates were found across all four treatment arms at 24 wks. Higher CDAI remission rate was observed for ABA versus ACT (+9%) and for CZP (+4%), but not for TCZ (-1%). With the predefined 15% margin, ACT was non-inferior to CZP and TCZ, but not to ABA. This underscores the efficacy of active conventional therapy based on MTX combined with glucocorticoids and may guide future treatment strategies for early RA.

Table.

Primary and key secondary outcomes at 24 weeks (ITT)

Active conventional therapy (ACT)Certolizumab+MTXAbatacept+MTXTocilizumab+MTXNo of pts (ITT)200203204188§Crude remission and response ratesCDAI remission42.0%47.8%52.5%41.0%ACR/EULAR Boolean remission34.0%38.4%37.3%31.4%DAS28 remission63.5%68.5%69.6%63.3%SDAI remission41.5%49.8%51.5%42.6%EULAR good response71.5%76.9%79.9%71.3%Difference (95% CI) in rates with Arm 1 as reference (adjusted)CDAI remissionRef4% (-5 to 13%)9% (0.1 to 19%)-1% (-10 to 9%)ACR/EULAR Boolean remissionRef4% (-6 to 13%)5% (-5 to 14%)-4% (-13 to 6%)DAS28 remissionRef3% (-6 to 11%)5% (-4 to 13%)-1% (-10 to 8%)SDAI remissionRef6% (-3 to 18%)9% (-0.3 to 18%)1% (-8 to 11%)EULAR good responseRef4% (-4 to 14%)8% (-2 to 18%)0.4% (-10 to 11%)

§17 patients allocated to Tocilizumab did not receive it due to its unavailability and were excluded from ITT.

Acknowledgments:

Manufacturers provided CZP and ABA.

Disclosure of Interests:

Merete L. Hetland Grant/research support from: BMS, MSD, AbbVie, Roche, Novartis, Biogen and Pfizer, Consultant of: Eli Lilly, Speakers bureau: Orion Pharma, Biogen, Pfizer, CellTrion, Merck and Samsung Bioepis, Espen A Haavardsholm Grant/research support from: AbbVie, UCB Pharma, Pfizer Inc, MSD Norway, Roche Norway, Consultant of: Pfizer, AbbVie, Janssen-Cilag, Gilead, UCB Pharma, Celgene, Lilly, Paid instructor for: UCB Pharma, Speakers bureau: Pfizer, AbbVie, UCB Pharma, Celgene, Lilly, Roche, MSD, Anna Rudin Consultant of: Astra/Zeneca, Dan Nordström Consultant of: Abbvie, Celgene, Lilly, Novartis, Pfizer, Roche and UCB., Speakers bureau: Abbvie, Celgene, Lilly, Novartis, Pfizer, Roche and UCB., Michael Nurmohamed Grant/research support from: Not related to this research, Consultant of: Not related to this research, Speakers bureau: Not related to this research, Björn Gudbjornsson Speakers bureau: Novartis and Amgen, Jon Lampa Speakers bureau: Pfizer, Janssen, Novartis, Kim Hørslev-Petersen: None declared, Till Uhlig Consultant of: Lilly, Pfizer, Speakers bureau: Grünenthal, Novartis, Gerdur Gröndal: None declared, Mikkel Ǿstergaard Grant/research support from: AbbVie, Bristol-Myers Squibb, Celgene, Merck, and Novartis, Consultant of: AbbVie, Bristol-Myers Squibb, Boehringer Ingelheim, Celgene, Eli Lilly, Hospira, Janssen, Merck, Novartis, Novo Nordisk, Orion, Pfizer, Regeneron, Roche, Sandoz, Sanofi, and UCB, Speakers bureau: AbbVie, Bristol-Myers Squibb, Boehringer Ingelheim, Celgene, Eli Lilly, Hospira, Janssen, Merck, Novartis, Novo Nordisk, Orion, Pfizer, Regeneron, Roche, Sandoz, Sanofi, and UCB, Marte Heiberg: None declared, Jos Twisk: None declared, Simon Krabbe: None declared, Kristina Lend: None declared, Inge Olsen: None declared, Joakim Lindqvist: None declared, Anna-Karin H Ekwall Consultant of: AbbVie, Pfizer, Kathrine L. Grøn Grant/research support from: BMS, Meliha C Kapetanovic: None declared, Francesca Faustini: None declared, Riitta Tuompo: None declared, Tove Lorenzen: None declared, Giovanni Cagnotto: None declared, Eva Baecklund: None declared, Oliver Hendricks Grant/research support from: Pfizer, MSD, Daisy Vedder: None declared, Tuulikki Sokka-Isler: None declared, Tomas Husmark: None declared, Maud-Kristine A Ljosa: None declared, Eli Brodin: None declared, Torkell Ellingsen: None declared, Annika Soderbergh: None declared, Milad Rizk Speakers bureau: AbbVie, Åsa Reckner: None declared, Per Larsson: None declared, Line Uhrenholt Speakers bureau: Abbvie, Eli Lilly and Novartis (not related to the submitted work), Søren Andreas Just: None declared, David Stevens: None declared, Trine Bay Laurberg Consultant of: UCB Pharma (Advisory Board), Gunnstein Bakland Consultant of: Novartis, UCB, Ronald van Vollenhoven Grant/research support from: BMS, GSK, Lilly, UCB, Pfizer, Roche, Consultant of: AbbVie, AstraZeneca, Biogen, Biotest, Celgene, Gilead, Janssen, Pfizer, Servier, UCB, Speakers bureau: AbbVie, Pfizer, UCB

OP0017 THERAPEUTIC DRUG MONITORING COMPARED TO STANDARD TREATMENT OF PATIENTS STARTING INFLIXIMAB THERAPY: RESULTS FROM A MULTICENTRE RANDOMISED TRIAL OF 400 PATIENTS

Background:

A lack or loss of response to TNFα inhibitors (TNFi) has been associated with low serum drug levels and formation of anti-drug antibodies (ADAb). Therapeutic drug monitoring (TDM), an individualised treatment strategy based on regular assessments of serum drug levels, has been suggested to optimise efficacy of TNFi. It is still unclear if TDM improves clinical outcomes, and the value of TDM has recently been included in the research agenda across different specialities. This first randomised controlled trial on the effectiveness of TDM in a range of immune mediated inflammatory diseases including rheumatic diseases, the NORwegian DRUg Monitoring trial part A (NOR-DRUM (A)) focus on the induction period of infliximab (INX) treatment.

Objectives:

To assess if TDM is superior to standard treatment in order to achieve remission in patients starting INX.

Methods:

In the investigator-initiated, randomised, open-label, multicentre NOR-DRUM (A) study, adult patients with rheumatoid arthritis (RA), psoriatic arthritis (PsA), spondyloarthritis (SpA), ulcerative colitis (UC), Crohn’s disease (CD) and psoriasis (Ps) starting INX therapy were randomly assigned to administration of INX according to a treatment strategy based on TDM (TDM arm) or to standard administration of INX without TDM (control arm). Study visits were conducted at each infusion. The primary endpoint was remission at week 30. In the TDM arm, the dose and interval were adjusted according to INX trough levels to reach the therapeutic range (Figure 1). If the patient developed significant levels of ADAb, INX was terminated. To guide the investigators, the TDM strategy was integrated in an interactive eCRF. The primary endpoint was analysed by mixed effect logistic regression in the full analyses set (FAS), adjusting for diagnoses. Infections and infusion reactions were specified as adverse events (AEs) of special interest.

Clinical trial.gov:NCT03074656

Results:

We enrolled 411 patients at 21 study centres between January 2017 and December 2018. 398 patients (RA 80, PsA 42, SpA 117, UC 80, CD 57, Ps 22) received the allocated strategy and were included in the FAS population. Demographic and baseline characteristics were comparable in both arms. TDM was not found to be superior to standard treatment with regard to the primary outcome. Remission at week 30 was reached in 100 (53%) and 106 (54%) of the patients in the TDM and control arm, respectively (adjusted difference, 1.5%; 95% confidence interval (CI), -8.2 to 11.1, p=0.78) (Figure 2). Consistent results were shown for all the secondary endpoints (Figure 3) and in the sensitivity analyses. Twenty patients (10%) in the TDM arm and 30 patients (15%) in the control arm developed significant levels of ADAb. The number of adverse events (AE) was similar in both groups, however infusion reactions were less frequent (5 patients (2.5%) vs 16 patients (8.0%)) in the TDM arm (difference 5.5% (95% CI 1.1, 9.8%))

Conclusion:

NOR-DRUM (A) is the first randomised trial to address effectiveness of TDM in the induction period of TNFi treatment, and the first trial to address TDM in rheumatic diseases. In this study, TDM was not superior to standard treatment in order to achieve remission. Although improved safety is indicated by a reduction in infusion reactions, implementation of TDM as a general strategy in the induction period of INX is not supported by the NOR-DRUM (A) study.

Disclosure of Interests:

Silje Watterdal Syversen Speakers bureau: Roche, Thermo Fisher, Guro Løvik Goll Consultant of: Novartis, Pfizer, Speakers bureau: Abbvie, Biogen, Boehringer Ingelheim, Orion Pharma, Eli Lilly, Novartis, Pfizer, MSD, Roche, UCB, Kristin Kaasen Jørgensen Consultant of: AOP Orphan, Celltrion, Sandoz, Speakers bureau: Norgine, Tillots, Øystein Sandanger: None declared, Joe Sexton: None declared, Inge Olsen: None declared, Johanna Gehin Speakers bureau: Roche, Marthe Kirksæther Brun: None declared, David Warren: None declared, Cato Mørk Consultant of: Abbot, Novartis, Celagene, Almiral, Galderma, ACO, Almiral, ACO, Speakers bureau: Novartis, Abbott, Abbvie, Celegene, LEO, Almiral, Galderma, Tore K. Kvien Grant/research support from: Received grants from Abbvie, Hospira/Pfizer, MSD and Roche (not relevant for this abstract)., Consultant of: Have received personal fees from Abbvie, Biogen, BMS, Celltrion, Eli Lily, Hospira/Pfizer, MSD, Novartis, Orion Pharma, Roche, Sandoz, UCB, Sanofi and Mylan (not relevant for this abstract)., Paid instructor for: Have received personal fees from Abbvie, Biogen, BMS, Celltrion, Eli Lily, Hospira/Pfizer, MSD, Novartis, Orion Pharma, Roche, Sandoz, UCB, Sanofi and Mylan (not relevant for this abstract)., Speakers bureau: Have received personal fees from Abbvie, Biogen, BMS, Celltrion, Eli Lily, Hospira/Pfizer, MSD, Novartis, Orion Pharma, Roche, Sandoz, UCB, Sanofi and Mylan (not relevant for this abstract)., Jørgen Jahnsen Consultant of: AbbVie, Boerhinger Ingelheim, Celltrion, Ferring, Janssen, Meda, MSD, Norgine, Novartis, Orion Pharma, Pfizer, Pharmacosmos, Takeda, and Sandoz., Speakers bureau: AbbVie, Astro Pharma, Boerhinger Ingelheim, BMS, Celltrion, Ferring, Hikma, Janssen, Meda, MSD, Napp Pharma, Orion Pharma, Pfizer, Pharmacosmos, Roche, Takeda, Tillotts and Sandoz, Nils Bolstad Consultant of: Pfizer, Janssen, Speakers bureau: Orion Pharma, Napp Pharmaceuticals, Takeda, Roche, Novartis, Espen A Haavardsholm Grant/research support from: AbbVie, UCB Pharma, Pfizer Inc, MSD Norway, Roche Norway, Consultant of: Pfizer, AbbVie, Janssen-Cilag, Gilead, UCB Pharma, Celgene, Lilly, Paid instructor for: UCB Pharma, Speakers bureau: Pfizer, AbbVie, UCB Pharma, Celgene, Lilly, Roche, MSD

OP0019 STABLE VERSUS TAPERED AND WITHDRAWN TREATMENT WITH TUMOR NECROSIS FACTOR INHIBITOR IN RHEUMATOID ARTHRITIS REMISSION (ARCTIC REWIND): A RANDOMISED, OPEN-LABEL, PHASE 4, NON-INFERIORITY TRIAL

Background:

Remission is the preferred treatment target in rheumatoid arthritis (RA), and many patients require biologic DMARDs to reach this state. It is debated whether tapering of tumor necrosis factor inhibitor (TNFi) treatment to discontinuation should be considered in RA patients who sustain remission on treatment (1).

Objectives:

The primary study objective was to assess the effect of tapering and withdrawal of TNFi on the risk of flares in RA patients in clinical remission.

Methods:

In the non-inferiority ARCTIC REWIND trial, RA patients in remission for at least 12 months on stable TNFi therapy were randomly assigned to continued stable TNFi or tapering (half-dose TNFi for 4 months, thereafter withdrawal of TNFi), with visits every four months. csDMARD co-medication was kept stable in both arms. Patients had to be in DAS remission at inclusion with 0/44 swollen joints. The primary endpoint was the proportion of patients with disease flare during the 12-month study period (defined as DAS>1.6, change in DAS>0.6 and 2 or more swollen joints, or the physician and patient agreed that a clinically significant flare had occurred). Full-dose TNFi was reinstated in case of flares in the tapering arm. The non-inferiority margin was 20%, with a predefined superiority test if non-inferiority was not shown. The inferiority null-hypothesis was tested in the per-protocol population by mixed effect logistic regression. Radiographs were scored by van der Heijde modified Sharp score (0 and 12 months, average of two readers, progression: ≥1 unit change). ClinicaltrialsNCT01881308.

Results:

We randomised 99 patients, 92 received the allocated treatment strategy, 84 were included in the per-protocol population. Baseline characteristics, clinical and ultrasound disease activity were balanced (Table). csDMARD co-medication was used by 93% in the stable and 88% in the tapering arm. In the primary analysis, 5% of patients in the stable TNFi arm experienced a flare during 12 months, compared to 63% in the tapering TNFi arm. The risk difference (95% CI) was 58% (42% to 74%, Fig 1), with stable treatment being deemed superior to tapering. 90% in the stable and 81% in the tapering arm did not show progression of radiographic joint damage, difference (95% CI) -9% (-24%, 6%). At 12 months, DAS scores, DAS remission and function were similar between groups (Fig 2). The numbers of adverse events (AE)/serious AE in the stable and tapering arm were 57/2 and 50/3, respectively, with 26 and 15 infections.

Conclusion:

In a randomised clinical trial assessing patients in prolonged and deep RA remission, we observed a large increase in the flare rate in patients who tapered and discontinued TNFi. Patients responded well to reinstated treatment and remission rates in the two study arms were comparable at 12 months.

References:

[1]Smolen et al. EULAR recommendations for the management of rheumatoid arthritis with synthetic and biological disease-modifying antirheumatic drugs: 2019 update. ARD 2020

Table 1.

Baseline values – n (%), mean (SD), or median (IQR)

Stable, n=45Tapering, n=47Age, yrs57 (11)58 (13)Female30 (67%)25 (53%)ACPA+35 (78%)36 (77%)Symptom duration, yrs10 (7)12 (7)DAS0.9 (0.4)0.8 (0.3)CRP mg/L1 (1 – 2)1 (1 – 3)No ulttrasound power Doppler signal in any of 32 joints42 (96%)44 (94%)

Disclosure of Interests:

Siri Lillegraven: None declared, Nina Paulshus Sundlisæter: None declared, Anna-Birgitte Aga: None declared, Joe Sexton: None declared, Inge Olsen: None declared, Åse Lexberg: None declared, Tor Magne Madland: None declared, Hallvard Fremstad: None declared, Christian A. Høili Consultant of: Novartis, Gunnstein Bakland Consultant of: Novartis, UCB, Cristina Spada: None declared, Hilde Haukeland Consultant of: Novartis, Inger M. Hansen: None declared, Ellen Moholt: None declared, Till Uhlig Consultant of: Lilly, Pfizer, Speakers bureau: Grünenthal, Novartis, Daniel Solomon Grant/research support from: Funding from Abbvie and Amgen unrelated to this work, Désirée van der Heijde Consultant of: AbbVie, Amgen, Astellas, AstraZeneca, BMS, Boehringer Ingelheim, Celgene, Cyxone, Daiichi, Eisai, Eli-Lilly, Galapagos, Gilead Sciences, Inc., Glaxo-Smith-Kline, Janssen, Merck, Novartis, Pfizer, Regeneron, Roche, Sanofi, Takeda, UCB Pharma; Director of Imaging Rheumatology BV, Tore K. Kvien Grant/research support from: Received grants from Abbvie, Hospira/Pfizer, MSD and Roche (not relevant for this abstract)., Consultant of: Have received personal fees from Abbvie, Biogen, BMS, Celltrion, Eli Lily, Hospira/Pfizer, MSD, Novartis, Orion Pharma, Roche, Sandoz, UCB, Sanofi and Mylan (not relevant for this abstract)., Paid instructor for: Have received personal fees from Abbvie, Biogen, BMS, Celltrion, Eli Lily, Hospira/Pfizer, MSD, Novartis, Orion Pharma, Roche, Sandoz, UCB, Sanofi and Mylan (not relevant for this abstract)., Speakers bureau: Have received personal fees from Abbvie, Biogen, BMS, Celltrion, Eli Lily, Hospira/Pfizer, MSD, Novartis, Orion Pharma, Roche, Sandoz, UCB, Sanofi and Mylan (not relevant for this abstract)., Espen A Haavardsholm Grant/research support from: AbbVie, UCB Pharma, Pfizer Inc, MSD Norway, Roche Norway, Consultant of: Pfizer, AbbVie, Janssen-Cilag, Gilead, UCB Pharma, Celgene, Lilly, Paid instructor for: UCB Pharma, Speakers bureau: Pfizer, AbbVie, UCB Pharma, Celgene, Lilly, Roche, MSD

SAT0148 TAPERING OF CONVENTIONAL SYNTHETIC DISEASE MODIFYING ANTI-RHEUMATIC DRUGS IN SUSTAINED RHEUMATOID ARTHRITIS REMISSION: RESULTS FROM A RANDOMIZED CONTROLLED TRIAL

Background:

Sustained remission is the goal of rheumatoid arthritis (RA) care, and more patients reach and maintain this state on conventional synthetic disease modifying anti-rheumatic drugs (csDMARDs) with treat-to-target strategies. The knowledge about whether csDMARDs can be tapered in RA remission is limited.

Objectives:

The primary objective of the study was to assess the effect of tapering of csDMARDs on the risk of flares in RA patients in sustained clinical remission.

Methods:

In the open, phase 4, non-inferiority ARCTIC REWIND trial, RA patients in clinical remission for ≥ 12 months on stable csDMARD therapy were randomised to continued stable csDMARD or half dose csDMARD. Patients had to be in DAS remission at inclusion with no swollen joints (of 44). The primary endpoint was the proportion of patients with a disease flare during 12 months (defined as a combination of DAS >1.6, change in DAS >0.6 and ≥2 swollen joints, or the physician and patient agreed that a clinically significant flare had occurred). Patients attended visits every 4 months, with extra visits in case of flares. The non-inferiority margin was 20%, with a predefined superiority test if non-inferiority was not shown. Mixed effect logistic regression was used to test the inferiority null-hypothesis in the per-protocol population. Radiographs at 0 and 12 months were scored by van der Heijde Sharp score (average score of two readers, progression: ≥1 unit change/year). Clinicaltrials.govNCT01881308.

Results:

We enrolled 160 patients, 155 received the allocated treatment strategy. Baseline characteristics were overall well balanced (Table). 78% of patients in the stable csDMARD arm and 84% in the half-dose csDMARD arm used methotrexate monotherapy. In the primary analysis, we observed flares in 6% of patients on stable csDMARD, compared to 25% in the half-dose csDMARD arm, giving a risk difference (95% CI) of 18.3% (7.2% to 29.3%, Fig 1). Non-inferiority could not be claimed, with the results showing superiority of the stable arm over the half-dose arm (Fig 1). Similar results were found in methotrexate monotherapy users. In the stable arm, 2/5 (40%) escalated DMARD medication following the flares, compared to 18/19 (95%) in the tapering arm. No progression of radiographic joint damage was observed in 79.5% of patients on stable DMARDs and 62.7% of those tapering, difference (95% CI) -17.7% (-33.0%, -2.3%, Fig 2E). At 12 months, 92% of patients in the stable and 85% of patients in the tapered arm were in DAS remission (Fig 2C). The frequency of adverse events was 75 in the stable arm and 53 in the tapered arm, with serious adverse events in 2 (2.6%) of patients in the stable and 4 (5.1%, including two serious infections) patients in the tapered arm.

Conclusion:

In RA patients in sustained remission on csDMARDs, continued csDMARD therapy with stable dosage led to significantly fewer disease activity flares and less frequent radiographic joint damage progression than tapered csDMARD treatment.

Table.

Baseline values; mean (SD), n (%) or median (IQR)

Stable, n=78Tapering, n=78Age, yrs55 (12)56 (12)Female50 (64%)54 (69%)ACPA+57 (73%)63 (81%)Symptom dur., yrs3.7 (1.8)3.4 (1.4)DAS0.8 (0.4)0.8 (0.3)CRP mg/L2 (1, 3)2.0 (1,3)MTX monotherapy61 (78%)65 (84%)

Disclosure of Interests:

Siri Lillegraven: None declared, Nina Paulshus Sundlisæter: None declared, Anna-Birgitte Aga: None declared, Joe Sexton: None declared, Inge Olsen: None declared, Hallvard Fremstad: None declared, Cristina Spada: None declared, Tor Magne Madland: None declared, Christian A. Høili Consultant of: Novartis, Gunnstein Bakland Consultant of: Novartis, UCB, Åse Lexberg: None declared, Inger Johanne Widding Hansen: None declared, Inger M. Hansen: None declared, Hilde Haukeland Consultant of: Novartis, Maud-Kristine A Ljosa: None declared, Ellen Moholt: None declared, Till Uhlig Consultant of: Lilly, Pfizer, Speakers bureau: Grünenthal, Novartis, Daniel Solomon Grant/research support from: Funding from Abbvie and Amgen unrelated to this work, Désirée van der Heijde Consultant of: AbbVie, Amgen, Astellas, AstraZeneca, BMS, Boehringer Ingelheim, Celgene, Cyxone, Daiichi, Eisai, Eli-Lilly, Galapagos, Gilead Sciences, Inc., Glaxo-Smith-Kline, Janssen, Merck, Novartis, Pfizer, Regeneron, Roche, Sanofi, Takeda, UCB Pharma; Director of Imaging Rheumatology BV, Tore K. Kvien Grant/research support from: Received grants from Abbvie, Hospira/Pfizer, MSD and Roche (not relevant for this abstract)., Consultant of: Have received personal fees from Abbvie, Biogen, BMS, Celltrion, Eli Lily, Hospira/Pfizer, MSD, Novartis, Orion Pharma, Roche, Sandoz, UCB, Sanofi and Mylan (not relevant for this abstract)., Paid instructor for: Have received personal fees from Abbvie, Biogen, BMS, Celltrion, Eli Lily, Hospira/Pfizer, MSD, Novartis, Orion Pharma, Roche, Sandoz, UCB, Sanofi and Mylan (not relevant for this abstract)., Speakers bureau: Have received personal fees from Abbvie, Biogen, BMS, Celltrion, Eli Lily, Hospira/Pfizer, MSD, Novartis, Orion Pharma, Roche, Sandoz, UCB, Sanofi and Mylan (not relevant for this abstract)., Espen A Haavardsholm Grant/research support from: AbbVie, UCB Pharma, Pfizer Inc, MSD Norway, Roche Norway, Consultant of: Pfizer, AbbVie, Janssen-Cilag, Gilead, UCB Pharma, Celgene, Lilly, Paid instructor for: UCB Pharma, Speakers bureau: Pfizer, AbbVie, UCB Pharma, Celgene, Lilly, Roche, MSD

Low levels of antibodies for the oral bacterium Tannerella forsythia predict cardiovascular disease mortality in men with myocardial infarction: A prospective cohort study

Antibody levels to periodontal pathogens in prediction of cardiovascular disease (CVD) mortality were explored using data from a health survey in Oslo in 2000 (Oslo II-study) with 12 1/2 years follow-up. IgG antibodies to four common periodontal pathogens; Tannerella forsythia (TF), Porphyromonas gingivalis (PG), and Treponema denticola (TD) all termed collectively the "red complex", and Aggregatibacter actinomycetemcomitans(AA) were analysed. The study sample consisted of 1172 men drawn from a cohort of 6,530 men who participated in the Oslo II-study, where they provided information on medical and dental history. Of the study sample, 548 men had reported prior myocardial infarction (MI) at baseline whereas the remaining 624 men were randomly drawn from the ostensibly healthy participants for comparative analyses. Dental anamnestic information included tooth extractions and oral infections. An inverse relation was found for trend by the quartile risk level of TF predicting CVD mortality, p-value for trend = 0.017. Comparison of the first to fourth quartile of TF antibodies resulted in hazard ratio (HR) = 1.82, 95% confidence interval 1.12-2.94, p = 0.015, adjusted for age, education, diabetes, daily smoking, and systolic blood pressure. Specificity comparing decile 1 to deciles 2-10 of TF predicting mortality was 92.3%. We found an increased HR by low levels of antibodies to the bacterium T. forsythia predicting CVD mortality in a 12 ½ years follow-up in persons who had experienced an MI but not among non-MI men. This novel finding constitutes a plausible causal link between oral infections and CVD mortality.

Biofilm-specific antibiotic tolerance and resistance

Biofilms are heterogeneous structures composed of bacterial cells surrounded by a matrix and attached to solid surfaces. The bacteria here are 100 to 1,000 times more tolerant to antimicrobials than corresponding planktonic cells. Biofilms can be difficult to eradicate when they cause biofilm-related diseases, e.g., implant infections, cystic fibrosis, urinary tract infections, and periodontal diseases. A number of phenotypic features of the biofilm can be involved in biofilm-specific tolerance and resistance. Little is known about the molecular mechanisms involved. The current review deals with both phenotypic and molecular mechanisms of biofilm-specific antibiotic tolerance and resistance.

Human papillomavirus subtypes in oral lesions compared to healthy oral mucosa

BACKGROUND

Human papillomaviruses (HPV) are involved in the etiology of cervix cancer, but it is still unclear whether they play a role in related oral lesions.

OBJECTIVES

The presence of HPV in oral leukoplakia biopsies (n=50) and oral squamous carcinoma biopsies (n=50) was compared to normal oral mucosa swabs (n=50) for the purpose of indicating a possible etiological role for the virus.

STUDY DESIGN

DNA was extracted from tissue biopsies and from mucosa swabs of control samples. Nested PCR was performed with primers targeting conserved sequences within the capsid gene L1. PCR products were sequenced to identify the HPV genotype.

RESULT

The results reveal a profile of low-risk HPV genotypes in oral leukoplakia similar to that in healthy controls, while HPV was less frequently observed in oral squamous carcinoma.

CONCLUSIONS

HPV does not seem to represent an important causal factor for the development of oral leukoplakia or oral squamous carcinoma.

Diversity and site-specificity of the oral microflora in the elderly

The purpose of the present study was to describe the bacterial diversity in the oral cavity of the elderly without root caries using bacterial microarrays, and to determine the site- and subject-specificity of bacterial colonization. Samples were collected from the tongue dorsum, mucosa of the buccal fold, hard palate, supragingival plaque from sound root surfaces, and subgingival plaque from the same roots. A new 16 S rRNA gene-based microarray method was used for the simultaneous detection of approximately 300 bacterial species. Overall, 175 species and clusters were detected, representing eight phyla. Species belonging to the genera Streptococcus, Veillonella, and Fusobacterium were common in all sites. The number of species per subject varied from 51 to 81. Statistical analyses revealed about 40 species or clusters with significant associations with at least one of the sites. The bacterial diversity was highest in the cheek and palate regions. Species typically associated with caries and periodontitis were detected rarely or not at all. The oral bacterial flora of the elderly appears to be diverse, and, to a large extent, site- rather than subject-specific.

Microarray analysis of the microflora of root caries in elderly

The present study used a new 16S rRNA-based microarray with probes for over 300 bacterial species to better define the bacterial profiles of healthy root surfaces and root caries (RC) in the elderly. Supragingival plaque was collected from 20 healthy subjects (Controls) and from healthy and carious roots and carious dentin from 21 RC subjects (Patients). Collectively, 179 bacterial species and species groups were detected. A higher bacterial diversity was observed in Controls than in Patients. Lactobacillus casei/paracasei/rhamnosus and Pseudoramibacter alactolyticus were notably associated with most RC samples. Streptococcus mutans was detected more frequently in the infected dentin than in the other samples, but the difference was not significant. Actinomyces was found more frequently in Controls. Thus, species other than Actinomyces and S. mutans may play a role as pathogens of RC. The results from this study were in general agreement with those of our previous study based on 16S rRNA gene sequencing.

RNA interference of the BMPR-IB gene blocks BMP-2-induced osteogenic gene expression in human bone cells

We have previously shown that human bone cells express bone morphogenetic protein receptor-IB (BMPR-IB). However, little is known about the precise role of this receptor in the response of osteoblastic genes to the BMP in these cells. To determine BMPR-IB-dependent osteoblastic gene expression, the present study examined the effects of BMPR-IB knockdown on BMP-induced osteoblast-associated genes. BMPR-IB mRNA and protein were markedly suppressed by transfection of cells with BMPR-IB siRNA. Using three different bone cell samples, BMP-2 stimulation of alkaline phosphatase (ALP), osteocalcin (OC), distal-less homeobox-5 (Dlx5) and core binding factor alpha-1 (Cbfa1) was found to be specifically and significantly reduced in the BMPR-IB siRNA-transfected cultures compared with that of control cultures. Our study has provided evidence that BMPR-IB-dependent signaling plays a crucial role in BMP-2 up-regulation of the ALP, OC, Dlx5 and Cbfa1 genes in bone cells, suggesting a pivotal role of this receptor in BMP-2-induced osteoblast differentiation in vitro. These findings thus suggest the possibility that BMPR-IB could be a therapeutic target for enhancing bone regeneration in vivo.

Severe chronic obstructive pulmonary disease: association with marginal bone loss in periodontitis

An association between chronic marginal periodontitis and chronic obstructive pulmonary disease (COPD) has been suggested. The aim of this study was to investigate whether chronic marginal periodontitis is more prevalent in very severe COPD than in other very severe respiratory diseases, and whether periodontitis in COPD is related to risk factors for periodontitis that are often present in COPD subjects. Orthopantomograms were collected from 130 patients with COPD and 50 patients with non-COPD evaluated for lung transplantation. Chronic marginal periodontitis was defined as a general marginal bone level > or = 4 mm. The prevalence of periodontitis was 44% in the COPD group vs. 7.3% in the non-COPD group. All oral measurements differed significantly between the groups. The difference in mean marginal bone level remained statistically significant when adjusting for age, gender and pack years smoked. In logistic regression analysis mean marginal bone level > or = 4 mm was identified as a factor significantly associated with severe COPD. This study demonstrates that chronic marginal periodontitis is common in patients with severe COPD. The high prevalence of periodontitis in COPD patients appears to be independent of possible risk factors for periodontitis such as age, pack years smoked, body mass index, use of corticosteroids and bone mineral density.

Ribotyping of bacteria from root canal and blood of patients receiving endodontic therapy

DNA restriction patterns and corresponding ribotypes of 26 bacterial isolates (Propionibacterium acnes, Peptostreptococcus prevotii, Fusobacterium nucleatum, Prevotella intermedia, Prevotella nigrescens, Actinomyces israelii, Streptococcus intermedius, and Streptococcus sanguis) recovered from patients with infected root canals and their peripheral blood, collected during and after endodontic therapy, were examined. Eleven additional reference strains including type strains were also examined. Purified DNA was digested with BglI,EcoRI, and HindIII. Hybridization was carried out with a digoxigenin-labeled cDNA probe obtained by reverse transcription of Escherichia coli 16S + 23S rRNA. Ribotypes of the bacteria recovered from root canal and blood showed identical characteristics within the patients, and differed between the patients. The results were confirmed when the similarity coefficient (S(AB)) of the ribotypes from the isolates were assessed by the Dendron computer-assisted system. These results suggested that the bacteria isolated from the blood originated from the root canal.

Subgingival plaque microbiota in HIV positive patients

AIM

To describe and compare the predominant bacterial and fungal species associated with gingivitis, periodontitis, and linear gingival erythema (LGE), in HIV positive subjects with different immune status.

METHODS

Viral loads and CD4 levels determined HIV disease status. From pooled subgingival plaque, 16S and 18S rDNA were cloned and sequenced to determine species identity.

RESULTS

One hundred and nine bacterial species were identified from 14 subjects. Nearly half of the species were not cultivable. Notably, the classical putative periodontal pathogens, Treponema denticola, Porphyromonas gingivalis and Tannerella forsythia were below the limit of detection and were not detected. Species of Gemella, Dialister, Streptococcus and Veillonella were predominant. In one HIV positive subject with periodontitis and low viral load, Gemella morbillorum, a known opportunistic pathogen, constituted 84% of the clones. Saccharomyces cerevisiae was the only fungal species detected in an LGE subject and in periodontitis subjects with high viral loads. In periodontitis patients with low viral loads, Candida albicans was predominant, while S. cerevisiae was only a minor component.

CONCLUSION

These case studies suggest that other bacterial species, rather than the classical periodontal pathogens, may be involved in periodontal diseases of subjects with HIV. These data are indicative of opportunistic infections in a highly susceptible immunocompromised host.

Shedding of a soluble form of BMP receptor-IB controls bone cell responses to BMP

Bone morphogenetic proteins (BMP) are members of the transforming growth factor beta (TGF-beta) superfamily and are involved in a wide variety of biological processes, including osteoblast differentiation and bone healing. The activities of the BMP are mediated by signal transduction via three BMP receptors (BMPR-IA, -IB and -II), which are thus essential for the biological actions of the BMP. Although the precise mechanisms which control the BMPR are not yet known, it is possible that post-translational regulation of these cell surface antigens by shedding could modulate their expression and thereby at least partly determine the response of the cells to the BMP. To test this possibility, the present study has examined whether soluble forms of the BMPR are produced by shedding from primary human bone cells in vitro. The results showed that human bone cells expressed both mRNA transcripts and antigens corresponding to BMPR-IA, -IB and -II. Incubation of the cells with phorbol 12-myristate 13-acetate (PMA), a potent inducer of proteolytic shedding, resulted in a pronounced decrease in cell surface expression of all three BMPR and, concurrently, the presence of "soluble" forms of these antigens in culture supernatants. Moreover, PMA treatment significantly reduced the level of BMP-2-induced Smad1/5 phosphorylation, a major early activation step in signal transduction initiated by BMP/BMPR interaction. It is notable that, while treatment of bone cells with interleukin-1beta (IL-1beta) also reduced the level of surface BMPR-IB, this inflammatory cytokine had no effect on BMPR-IA or -II levels, hence only the soluble form of BMPR-IB was detected. Furthermore, in addition to down-regulating BMP-2-induced Smad1/5 phosphorylation, IL-1beta also caused a reduction in the level of BMP-2-induced alkaline phosphatase activity and osteocalcin expression, both closely associated with bone cell differentiation. In conclusion, our study has provided evidence, for the first time, that BMPR can be modulated at the cell surface by the shedding of a soluble form of the antigen, resulting in a markedly diminished response to BMP-2 in vitro.

Synovial inflammation in active rheumatoid arthritis and psoriatic arthritis facilitates trapping of a variety of oral bacterial DNAs

OBJECTIVE

To investigate the presence of oral bacterial DNAs in serum and synovial fluid (SF) of patients with active rheumatoid arthritis (RA) and psoriatic arthritis (PsA).

METHODS

Serum and SF samples from 16 RA patients, 14 PsA patients, and 9 osteoarthritis (controls) patients were extracted for oral bacterial DNA. This was used in a checkerboard DNA-DNA-hybridization set up, to identify 40 different bacteria.

RESULTS

Mean number +/- standard deviation (SD) of oral bacterial species in sera were 6.2 (3.2) in the RA group (p = 0.004) and 5.4 (2.7) in the PsA group (p = 0.009) compared to 2.1 (1.7) in the controls. Periodontitis associated species Porphyromonas gingivalis and Prevotella nigrescens were exclusively detected in RA and PsA. Mean number (+/- SD) of oral bacterial species in SF were 14.0 (6.8) in the RA (p = 0.001) and 19.4 (7.1) in the PsA group (p < 0.001) compared to 4.0 (1.7) in controls. P. gingivalis, Tannerella forsythensis and Prevotella intermedia were exclusively identified in RA and PsA SF. Higher means of DNAs were found in RA SF compared to RA serum (p < 0.001), and in PsA SF compared to PsA serum (p < 0.001). Higher concentrations of bacterial DNAs were found in RA and PsA compared to controls.

CONCLUSION

Higher variety and concentrations of oral bacterial DNAs were found in SF compared to serum of RA and PsA patients. These findings indicate that synovial inflammation in RA and PsA may favor trapping of oral bacterial DNAs, suggesting a perpetuating effect of oral pathogens in joint disease.

Genotypic relatedness of yeasts in thrush and denture stomatitis

BACKGROUND/AIM

Candida is an opportunistic pathogen. Understanding its genetic characters might increase our understanding of the pathogenesis of candidosis. We examined the genetic relationships of yeasts from the most common forms of oral candidosis: thrush and denture stomatitis.

METHODS

Yeasts were sampled from palate, buccal mucosa, gingival sulci/periodontal pockets and/or denture fitting surface of 19 thrush patients and 22 denture stomatitis patients. Random amplified polymorphic DNA and the Dendron computer-assisted program were used to determine the genotypic relatedness of the yeasts.

RESULTS

A dendrogram generated from 105 thrush isolates had similarity coefficients (S(AB)) ranging from 0.58 to 1 with four clusters derived at S(AB) 68%. Another dendrogram was generated from 91 isolates from denture stomatitis, with S(AB) ranging from 0.59 to 1. Three clusters were established at S(AB) 71%. In a composite dendrogram incorporating the thrush and denture stomatitis data and orally healthy data compiled from a previous study, five genotypic clusters were generated at S(AB) 68%. Cluster II, the most dominant, comprised isolates from thrush, denture stomatitis and healthy conditions, while clusters III and IV contained yeasts mainly from thrush.

CONCLUSIONS

Palatal yeast carriage was significantly increased in thrush and denture stomatitis, also after radiation, chemotherapy and denture wearing. The buccal mucosa was favorable for yeast colonization regardless of oral condition. Yeasts in thrush were more diverse than in conditions of oral health. The common clone (II) of infecting yeasts and commensals suggested that commensals could induce thrush and denture stomatitis, whereas the unique clones in thrush (III, IV) might have been established through strain replacement or maintenance with minor genetic variation.

Bone morphogenetic protein receptors and bone morphogenetic protein signaling are controlled by tumor necrosis factor-α in human bone cells

Bone morphogenetic proteins (BMP) stimulate osteoblast differentiation by signal transduction via three BMP receptors (BMPR-IA, -IB and -II), whereas the inflammatory cytokine tumor necrosis factor-alpha (TNF-alpha) has been shown to suppress osteoblast differentiation. Although the mechanisms which regulate the BMPR are not yet known, it is possible that they may be negatively controlled by TNF-alpha, thereby inhibiting BMP-induced osteoblast differentiation. To test this hypothesis, we have examined the effects of TNF-alpha on BMPR-IA, -IB and -II expression and the functional consequences of this cytokine on BMPR-mediated functions in human bone cells. The results showed that although TNF-alpha down-regulated BMPR-IA and -II transcripts, it increased the level of BMPR-IB mRNA via a MAPK-dependent pathway. In marked contrast, however, TNF-alpha nevertheless caused marked down-regulation of the expression of the BMPR-IB surface antigen specifically. Moreover, the cytokine-induced decrease in BMPR-IB expression was found to be associated with the concurrent presence of a 'soluble' form of this antigen in supernatants of TNF-alpha-treated cultures. Furthermore, the TNF-alpha-induced loss of BMPR-IB was found to ablate BMP-2-stimulated bone cell functions, including phosphorylation of Smad1/5/8, alkaline phosphatase activity and osteocalcin expression. In conclusion, our study has provided evidence, for the first time, that BMPR can be differentially modulated by TNF-alpha at both the post-transcriptional and post-translational levels, with the TNF-alpha-induced shedding of the BMPR-IB antigen associated with a significantly diminished response to BMP-2 in vitro.

Effects of ultrasound on transforming growth factor-beta genes in bone cells

Therapeutic ultrasound (US) is a widely used form of biophysical stimulation that is increasingly applied to promote fracture healing. Transforming growth factor-beta (TGF-beta), which is encoded by three related but different genes, is known to play a major part in bone growth and repair. However, the effects of US on the expression of the TGF-beta genes and the physical acoustic mechanisms involved in initiating changes in gene expression in vitro, are not yet known. The present study demonstrates that US had a differential effect on these TGF-beta isoforms in a human osteoblast cell line, with the highest dose eliciting the most pronounced up-regulation of both TGF-beta1 and TGF-beta3 at 1 hour after treatment and thereafter declining. In contrast, US had no effect on TGF-beta2 expression. Fluid streaming rather than thermal effects or cavitation was found to be the most likely explanation for the gene responses observed in vitro.

Scanning and transmission electron microscopy demonstrates bacteria in osteoradionecrosis

According to the current concept of osteoradionecrosis such tissue has become hypoxic, hypovascular and hypocellular and it has previously failed to show any bacterial growth. By using a molecular method, i.e., DNA-DNA hybridization, the presence of microorganisms in radionecrotic bone has formerly been demonstrated by us. The aim of the present study was to visualise bacteria in such bone by using scanning and transmission electron microscopy. Fourteen deep medullar specimens from resected radionecrotic mandibles were studied. Microorganisms were detected in 9 of the 14 samples (64%). The bacteria seen included rods, spirochetes and cocci, with rods being the predominant cells. One sample also contained yeasts (blastoconida and pseudohyphae). The data from this study strongly suggest an association between microorganisms and osteoradionecrosis. This may call for a revision of its presumed pathophysiology, including the possibility of an infectious etiology.

DNA–DNA hybridization demonstrates multiple bacteria in osteoradionecrosis

Bone necrosis secondary to radiation was previously attributed to trauma of devitalized bone and microbiological sepsis. However, conventional microbiological technique has failed to demonstrate microorganisms throughout osteoradionecrotic bone, claimed to be hypoxic, hypovascular and hypocellular. The aim of the present study was to examine such bone for bacteria using DNA-DNA hybridization. Compared to standard culture methods this technique enables the investigation of a vast number of bacteria in a fairly short time. Twelve deep medullary specimens from resected radionecrotic mandibles were studied. A multitude of bacterial species were detected, most of them anaerobic. Porphyromonas gingivalis was the most predominant organism, followed by Fusobacterium nucleatum subspecies polymorphum. All samples contained Actinomyces, Prevotella and F. nucleatum. The results of this study indicate that bacteria, particularly anaerobes, may play a more fundamental role in the pathophysiology of osteoradionecrosis than being merely surface contaminants.

Acute glomerulonephritis associated with streptococcus pyogenes with concomitant spread of streptococcus constellatus in four rural families

We studied history, renal histopathology and microbiology of an epidemic of acute glomerulonephritis associated with throat infections and uncommon culture results in four neighbour families. A 40-year-old man (index patient) was referred to a university hospital for dialysis and kidney biopsy due to a suspected acute glomerulonephritis. An acute tonsillitis had preceded the condition. Penicillin treatment had been started four days before the discovery of renal failure. Throat swabs were positive for beta-hemolytic streptococci, group C (GCS). GCS were also found in throat cultures from his wife and two of their children. The bacteria were typed as Streptococcus constellatus. A third child had S. constellatus expressing Lancefield antigen group G. A neighbour and two of his children fell ill the following week with renal involvement. Throat swabs from both these children were positive for S. constellatus. His third child had erythema multiforme and S. constellatus in the throat while a fourth child had beta-hemolytic streptococci group A; Streptococcus pyogenes. Kidney biopsies on the index patient and his neighbour showed an acute diffuse prolipherative glomerulonephritis compatible with acute post-streptococcal nephritis and microbiological analysis of renal tissue revealed in both cases S. pyogenes and S. constellatus. The families had had much contact and had consumed unpasteurized milk from our index patient's farm. In four of seven persons in two additional neighbouring families S. constellatus was found in throat swabs during the same month while two persons carried Streptococcus anginosus expressing the Lancefield C antigen. In conclusion spread of S. constellatus coincided with the occurrence of four cases of acute glomerulonephritis. The two biopsied patients had both S. pyogenes and S. constellatus present in renal tissue. The epidemic either suggested that the outbreak of glomerulonephritis was due to S. pyogenes but coincided with the transmission and colonization of S. constellatus or that the S. constellatus strains were highly pathogenic or nephritogenic and that this organism can be transmitted in such cases.

Human alveolar bone cell adhesion and growth on ion-implanted titanium

Surface characteristics play a vital role in determining the biocompatibility of materials used as bone implants. Calcium ion implantation of titanium was previously reported to enhance osseointegration and bone formation in vivo, although the lack of consistent and reproducible effects highlight the need to understand the basic mechanisms involved in the response of target cells to such surfaces. The aim of this study was therefore to measure the precise effects of ion implantation of titanium on bone cells in vitro. Alveolar bone cells were seeded on the surface of polished titanium disks implanted with calcium, potassium, and argon ions. Using radioisotopically tagged bone cells, the results showed that although the calcium ion implanted surface reduced cell adhesion, it nevertheless significantly enhanced cell spreading and subsequent cell growth. In contrast, few differences in bone cell behavior were observed between the potassium- and argon-implanted titanium and the control nonimplanted titanium disks. These findings suggest the possibility that the calcium-implanted surface may significantly affect the biocompatibility of titanium implants by enhancing bone cell growth. Surface modification by ion implantation could thus prove to be a valuable tool for improving the clinical efficacy of titanium for bone repair and regeneration in vivo.

Gene expression profiling of bone cells on smooth and rough titanium surfaces

Titanium (Ti) and Ti alloys are widely used as dental and orthopaedic implants, but the effects of the surface characteristics of these materials on the response of cells and target tissues is not well understood. The present study has therefore examined the effects of a rough Ti (RT) and a smooth Ti (ST) surface on human bone cells in vitro. Scanning electron microscopy showed attachment and spreading of cells on both surfaces. Expression profiling using ATLAS gene arrays showed marked differences in gene responses after 3 h of culture. A number of osteoblast genes were identified as "roughness response" genes on the basis of changes in expression on the RT compared with the ST surfaces. The surface roughness of Ti was thus found to have a profound effect on the profile of genes expressed by the bone cells, and suggests that improvements in the biological activity and possibly the clinical efficacy of these materials could be achieved by selective regulation of gene expression mediated by controlled modification of Ti surface.

Processing, characterisation and biocompatibility of iron-phosphate glass fibres for tissue engineering

Iron-phosphate glass fibres based on the CaO-Na2O-Fe2O3-P2O5 system have been processed and characterised via thermal, XRPD, dissolution rates, diameter and biocompatibility studies. The compositions investigated were fixed at 50mol% P2O5, and the CaO content was varied between 30, 35 and 40mol%. The Fe2O3 was added in low amounts from 1-5mol%, substituting it for the Na2O mol%. The number of Tc (crystallisation temperature) peaks detected from the thermal analysis traces only showed correlation with XRPD analysis, for five out of the 15 compositions investigated. It has been suggested that either the crystalline phases had very similar Tc temperatures or that the other phase(s) were present in very small quantities. There was a good match seen with number of Tm (melting temperature) peaks picked up from the DTA traces, with the number of phases identified from XRPD analysis. The main phases identified from XRPD were NaCa(PO3)3, CaP2O6 and NaFeP2O7. Using network connectivity (NC), predictions on Qn species present within the compositions investigated were made. The predicted species (metaphosphates) matched with phases identified from XRPD analysis. A decrease in dissolution rates for the bulk glass and glass fibres was seen with an increase in CaO mol%, along with an increase in Fe2O3 mol%. An increase in fibre dissolution rates was seen with a decrease in diameter size. The biocompatibility studies were conducted using a conditionally immortal muscle precursor cell line derived from the H-2Kb-tsA58 immortomouse. It was found that iron-phosphate glass fibres containing 4-5mol% Fe2O3 was sufficient for cell attachment and differentiation. It was seen that myotubes formed along the axis of the fibres (which was indicative of differentiation). The biocompatibility of these compositions was attributed to the enhanced chemical durability of the glass fibres.

beta-Lactamase production and antimicrobial susceptibility of subgingival bacteria from refractory periodontitis

This study assessed the extent of beta-lactamase-producing bacteria in subgingival plaque samples obtained from 25 patients with refractory marginal periodontitis in the USA. beta-Lactamase-positive isolates were characterized using commercial diagnostic kits and partial sequencing of the 16S rRNA gene. The susceptibilities to different antimicrobial agents were tested and, in addition, the isolates were screened for the presence of extended spectrum beta-lactamases (ESBLs). beta-lactamase-producing bacteria were detected in 18 (72%) patients. The most prominent beta-lactamase-producing organisms belonged to the anaerobic genus Prevotella. Other enzyme-producing anaerobic strains were Fusobacterium nucleatum, Propionibacterium acnes and Peptostreptococcus sp. Facultative bacteria, such as Burkholderia spp., Ralstonia pickettii, Capnocytophaga spp., Bacillus spp., Staphylococcus spp. and Neisseria sp., were also detected among the enzyme-producers. Minimum inhibitory concentrations (MICs) of ampicillin and amoxicillin were in the range 1.5-256 micrograms/ml and 4-256 micrograms/ml, respectively, for the isolates of the Prevotella species. All Prevotella isolates were susceptible to amoxicillin/clavulanate and metronidazole, but they showed variable resistance to tetracyclines. Two of the Prevotella isolates had high MICs of cefotaxime and ceftazidime. ESBL activity was not detected in any of the beta-lactamase-producing isolates by the Etest method. Thus, our study demonstrated a wide variety of beta-lactamase-producing bacteria that may play a role in refractory periodontal disease.

Phosphate glasses for tissue engineering: Part 1. Processing and characterisation of a ternary-based P2O5-CaO-Na2O glass system

This paper presents the results of a study of the thermal properties, X-ray powder diffraction (XRPD), NMR and solubility of a range of phosphate-based glasses. Ion release and pH measurements were also obtained. The compositions were limited by fixing the P2O5 mol% content at 45, 50 and 55 mol%, and varying the CaO mol% at 30, 35 and 40 mol%. Initial data collected from thermal analysis showed an increase in the Tg values, with increasing CaO mol%, as expected. An increase in crystallisation temperatures with increasing CaO mol% was also observed, with sharp peaks indicating the presence of single and/or double phases. Initial XRPD data revealed that the 45 mol% P2O5 precipitated a calcium bridged trimetaphosphate (Na4Ca[PO3]6) at the sodium oxide contents of 25 and 20 mol%, but at the 15 mol% level two phases formed, NaCa[PO3]3 and Ca2P2O7. The 50 mol% P2O5 compositions showed two sodium phosphate-rich phases [NaCa(PO3)3 and NaPO3] for the lower calcium containing compositions, and a calcium phosphate phase [CaP2O6] for compositions with higher CaO mol%. The 55 mol% P2O5 compositions, exhibited similar phases for the lower calcium containing compositions, and a single calcium phosphate phase (CaP2O6) was identified for the higher calcium containing composition. NMR analysis revealed the presence of Q1 and Q2 species in the 45 mol% P2O5 compositions, and Q2 species present in the 50 and 55 mol% P2O5 compositions. The non-linear data obtained from the thermal and solubility analyses conducted were attributed to the packing density of the 45 mol% P2O5 compositions. The solubility was seen to decrease with increasing CaO mol%, for all the glasses investigated, and all the compositions showed a gradual decrease in pH with time, and this was accounted for by the release of Na+ and Ca2+ ions into solution.

Phosphate glasses for tissue engineering: Part 2. Processing and characterisation of a ternary-based P2O5-CaO-Na2O glass fibre system

This paper presents the results of a study of the thermal properties, solubility and dimensions of a range of phosphate-based glass fibres (PB-GFs). The glass compositions were limited by fixing the P2O5 content to 45, 50 and 55 mol%, and varying the CaO mol% at 30, 35 and 40. PB-GFs were obtained from the 50 and 55 mol% P2O5 compositions; however, we were unable to obtain fibres from the 45 mol% compositions. This was linked to the cross-linked density, network connectivity and average chain length of the compositions studied. With regards to thermal parameters investigated, initial data showed an increase of the Tg and crystallisation temperatures with increasing CaO mol% at each fixed phosphate content. A decrease in Tg temperatures was also observed with increasing P2O5 content to 55 mol%. The crystallisation temperatures obtained for compositions with fixed phosphate at 55 mol%, showed a reverse pattern, with a decrease in values as compared to the fixed 50 mol% phosphate compositions. The diameters of the fibres all decreased with increasing RPMs as expected, and the solubility also increased with increasing RPMs. This was related to the increased surface area of the higher RPM fibres. There was also a decrease seen in solubility with increasing CaO mol%.

Roughness response genes in osteoblasts

Titanium (Ti) and Ti alloys are widely used as dental and orthopedic implants, but the effects of the surface characteristics of these materials, including roughness, on the response of target tissues in vivo are not well understood. The present study has therefore examined the effects of a moderately rough (sand-blasted, acid-etched; SLA) Ti surface, a highly rough (plasma-sprayed; TPS) surface, and a smooth surface (SMO) on bone cells in vitro. X-ray photoelectron spectroscopy showed that these surfaces had similar surface chemistry, while scanning electron microscopy suggested that the SLA provided a transiently less biocompatible surface, with initially less well-attached cells. SLA also delayed bone cell growth compared with SMO, whereas the TPS surface elicited the greatest increase in cell numbers. In addition, expression profiling using the ATLAS gene array showed marked differences in gene responses after 3 h of incubation; this increased further after 24 h, with TPS generating the largest number of up- and down-regulated genes compared with SLA and SMO. A number of osteoblast genes were also identified as 'roughness' genes on the basis of their similar response on SLA and TPS, compared with SMO. These findings show, for the first time, that the surface roughness of Ti has a profound effect on the profile of genes expressed by bone cells and suggest that improvements in the biological activity and possibly the clinical efficacy of these materials could be achieved by selective regulation of gene expression mediated via modification of surface roughness.

Changes in transforming growth factor-beta1 in gingival crevicular fluid following periodontal surgery

OBJECTIVES

Growth factors play a major part in wound healing, including in the periodontium. However, the presence of growth factors in gingival crevicular fluid (GCF) in humans during periodontal wound healing has not yet been determined. Our hypothesis is that such factors are present in GCF and that changes in their levels might be of value as a prognostic marker of wound-healing activity and therapeutic progress following periodontal surgery. The aim of this study was therefore to measure transforming growth factor-beta1 (TGF-beta1) in GCF collected from sites that have undergone guided tissue regeneration (GTR) and conventional flap (CF) surgery and to compare these with GCF collected from unaffected healthy sites.

MATERIALS AND METHODS

GCF samples were collected, using filter paper strips, at baseline (pre-surgical) and then at intervals up to 26 weeks from 16 patients undergoing GTR and from 11 patients undergoing CF surgery. After elution and acid treatment, TGF-beta1 levels were measured by ELISA.

RESULTS

Treatment of periodontal defect sites significantly reduced the mean probing pocket depth (PPD) and improved the mean lifetime cumulative attachment loss (LCAL). Average GCF volumes also significantly increased at all sites at 2 weeks post-surgery and thereafter declined to baseline levels, except at the GTR test sites that were still elevated at 7 weeks. TGF-beta1 could be detected in almost all GCF samples, and 2 weeks after surgery, the average levels increased two-fold at the surgically treated but not at the control sites, which remained unchanged.

CONCLUSION

TGF-beta1 is readily detectable in GCF and increases transiently following periodontal surgery. This suggests that changes in the levels of this growth factor in GCF might be useful for monitoring the progress of periodontal repair and regeneration.

Adhesion of bone cells to ion-implanted titanium

The use of ion-implantation to encourage osseointegration has been investigated using an in vitro model cell culture system and surface analysis. Polished titanium discs were implanted with calcium, potassium and argon ions. The adhesion of bone-derived cells was measured using radioactively labeled cells and the morphology examined using scanning electron microscopy. Similar numbers of cells were found to adhere to the potassium and argon-implanted titanium as to control (non-implanted) titanium. However, adhesion to the calcium-implanted titanium discs was significantly reduced. Moreover, although the cells were found to be well spread on the calcium and potassium-implanted titanium, a much greater proportion of cells appeared to remain rounded and poorly attached on the argon-implanted surface. These differences are discussed in relation to the observed surface roughness and chemistry, which were assessed using interferometry and X-ray photoelectron spectroscopy, respectively.

DNA injection in combination with electroporation: a novel method for vaccination of farmed ruminants

Injection of plasmid DNA encoding antigens into rodents followed by electroporation improved the immune response when compared with injection without electroporation (Widera et al. J Immunol 2000;164:4635-40; Zucchelli et al. J Virol 2000;74:11598-607; Kadowaki et al. Vaccine 2000;18:2779-88). The present study describes the extension of this technology to farm animals, by injecting plasmid DNA encoding mycobacterial antigens (MPB70, Ag85B and Hsp65) into the muscles of goats and cattle using two different types of electrodes, both allowing DNA delivery at the site of electroporation. The animals were vaccinated under local anaesthesia without any observed immediate or long-term distress or discomfort, or any behavioural signs of muscle damage or pathological changes after the electroporation. DNA-injected and electroporated goats showed increased humoral response after the primary vaccination when compared with nonelectroporated animals. Improved T-cell responses following electroporation were observed in hsp65 DNA-vaccinated cattle. DNA injection with or without electroporation did not compromise the specificity of the tuberculin skin test. In conclusion, a protocol applying in vivo electroporation free of side effects to farmed ruminants was established. In addition, we show that DNA vaccination in combination with electroporation can improve the primary immune responses to the encoded antigens.

Effects of phosphate-based glasses on T lymphocytes in vitro

Host responses to implanted materials can lead to the production of inflammatory mediators and thereby induce potentially adverse reactions, including the activation of T lymphocytes. Although such cells are a central component of immune reactions and likely to be fundamental in determining the long-term clinical efficacy of implants, their response to biomaterials is not well known. This study has therefore examined the in vitro effects of phosphate-based glasses (PG), which can be produced with pre-determined solubility and may be promising materials for promoting the regeneration of new bone and other tissues. Extracts of PG which were modified by the addition of Ca, Co, Zn, and Fe oxides were found to cause only very low levels of activation of human peripheral blood T lymphocytes over a period of 6 days, as measured by changes in DNA synthesis. In contrast, the activation of these cells by concanavalin A, a potent T cell mitogen, was partially inhibited by extracts of a high-Ca PG and nearly totally ablated by the Co-derived extract. These studies show that, despite their apparent inability to activate immunologically responsive cells directly, substances which leach out of metal-containing PG implant materials have the potential to modulate inflammatory reactions.

Expression profiling of periodontal ligament cells stimulated with enamel matrix proteins in vitro: a model for tissue regeneration

Several studies have examined the role of enamel matrix proteins in root formation and periodontal regeneration, although most of these have focused on a few specific genes which had previously been implicated. However, recent advances in expressional profiling have made it possible to examine the range of genetic responses involved in these processes. In the present experiments, we have therefore utilized this technique to determine the effects of enamel matrix proteins on the gene activities of periodontal ligament cells in vitro. Such cells were found to have an elevated level of RNA synthesis compared with control cells. Moreover, hybridization of the cDNA prepared from this RNA to gene array filters showed that there was differential expression of 121 genes, most of which had not previously been associated with periodontal regeneration. Some of these selective changes in gene activity might thus reflect the fundamental events that underlie periodontal development.

Keratinocyte growth factor receptor is up-regulated in cyclosporin A-induced gingival hyperplasia

Keratinocyte growth factor stimulates the growth and activity of epithelial cells via the keratinocyte growth factor receptor. We have recently shown that the growth factor is markedly elevated in cyclosporin A-induced gingival hyperplasia tissue in vivo, but the effects of cyclosporin A on the receptor are not yet known. The present study was therefore carried out to determine whether expression of the keratinocyte growth factor receptor is up-regulated in gingival hyperplasia compared with normal gingiva. Using immunohistochemistry and the reverse-transcribed polymerase chain-reaction, we obtained results which showed that receptor antigen and gene transcript levels were both elevated in gingival hyperplasia tissue. In addition, flow cytometry and the reverse-transcribed polymerase chain-reaction showed that the receptor and mRNA were also higher in gingival epithelial cells following incubation with cyclosporin A in vitro. These findings suggest that the keratinocyte growth factor-receptor pathway of mesenchymal-epithelial interaction could play an important part in the molecular pathogenesis of gingival hyperplasia.

The effect of MgO on the solubility behavior and cell proliferation in a quaternary soluble phosphate based glass system

This paper presents a systematic study of the MgO-CaO-Na(2)O-P(2)O(5) glass system, which has great potential to be used as temporary hard and soft tissue implant materials. An overall study of solubility behavior of ternary and quaternary-based phosphate glass system have been carried out in order to understand the out-leaching progress of different ions and to determine their effect on cell proliferation. Originally, soluble phosphate based glasses within the ternary glass system of Na(2)O-CaO-P(2)O(5) have been developed to create a simple baseline system. This paper, however, presents the development of this system by introducing magnesium oxide as a partial calcium oxide substitute and solubility behaviors as well as cell studies have been carried out to check the effect on magnesium ions. Glasses have been prepared via standard glass melting techniques and their solubility behavior has been tested in distilled water via simple weight loss, pH and ion measurements. The way the glasses dissolve is an inverse exponential behavior which is mirrored by the calcium ion release. Other ions show a less exponential behavior. The MTT test has been used to check preliminary in vitro studies on a human MG63 cell line and the result indicates that cell proliferation is increased for glasses with minimal CaO substitution.

Paratuberculosis with special reference to cattle. A review

Paratuberculosis is a chronic, granulomatous enteritis caused by Mycobacterium avium subspecies paratuberculosis affecting domestic and wild ruminants. The symptoms of clinical paratuberculosis are chronic diarrhoea and progressive weight loss while subclinically infected animals mainly have decreased production. The infection is widespread throughout the world and causes substantial financial losses for the farming industry. One of the major obstacles in the control of this disease, is the difficulty of identifying subclinically infected animals. This review gives a summary of several aspects of paratuberculosis including clinical importance, pathology, immunology and properties of the infectious agent. Special emphasis will be on the available diagnostic methods, their use and limitations.

[Bacteria-killing viruses, Stalinists and "superbugs"]

In June 2000, the WHO warned that the level of resistance to drugs used to treat common infectious diseases is now reaching a crisis point. If world governments do not control infections better in order to slow down the development of drug resistance, entire populations could be wiped out by superbugs against which there is no efficient treatment. Development of resistance is due to both underuse and overuse of drugs, and strategies have been worked out, to slow down the development of resistance for instance by the Norwegian Ministry of Health and Social Affairs. The present article deals with an old principle, mainly developed behind the Iron Curtain, which is now attracting renewed attention in the west: the application of bacterial viruses (bacteriophages) in the fight against bacteria. According to clinical trials in Eastern Europe, mostly uncontrolled, phages have been used successfully in treatments against antibiotic-resistant bacteria, for instance in suppurative wound infections, gastroenteritis, sepsis, osteomyelitis and pneumonia. These encouraging data are supported by recent findings in well-controlled animal models demonstrating that phages can rescue animals from a variety of fatal infections. The present review discusses possible advantages and limitations of phage treatment in humans.

Glass reinforced hydroxyapatite for hard tissue surgery--part II: in vitro evaluation of bone cell growth and function

Hydroxyapatite (HA)-based materials are considered to be potentially useful as bone implant materials, particularly those reinforced with glass to improve mechanical strength. However, the precise effects of glass-reinforced HA on the growth and functions of bone cells are still unclear. The present study has therefore examined the response of human osteoblast-like cells to HA and HA reinforced with two different proportions of glass, namely 2.5% and 5%. All materials enabled the cells to attach and proliferate during 7 days in culture and, although the growth was less than on control plastic surfaces, there was no deleterious effect of the 5% glass composite compared with HA alone. Flow cytometry analysis showed that there was no effect on cell size and granularity, but there were marked and highly selective changes in the expression of certain connective tissue proteins. Thus, while bone sialoprotein and osteonectin were down-regulated on HA alone, the expression of these antigens was relatively enhanced on the composite materials, and collagen type I was also up-regulated on the glass-reinforced HA. Thus, modulation of the glass composition of HA materials could be used to produce not only improved mechanical strength, but also enhanced biocompatibility.

Effects of therapeutic ultrasound on osteoblast gene expression

Ultrasound (US) is commonly used as a physiotherapy aid for a number of types of injury to soft connective tissues and for fracture healing. However, the precise effects of therapeutic US on tissue healing processes are not clearly understood, although they are likely to involve changes in key cellular functions. The present study has therefore examined the effects of several US intensity levels on the activity of two bone-associated proteins, alkaline phosphatase (ALP) and osteopontin (OP) in a human cell line, MG63, using RT-PCR. ALP showed progressively higher expression with increasing US intensities, whereas OP responded differently, showing down-regulation at 120 mW/cm2, the lowest US exposure. OP expression was considerably less affected overall compared with the relative response of ALP to the same US doses. The results show that there is a differential response to therapeutic levels of US, since ALP and OP clearly exhibited gene-specific response profiles. These findings suggest that modifying the parameters of US exposure could be used to improve repair and regeneration processes and enhance the clinical efficacy of implanted biomaterials for tissue engineering.