Ashcroft, G. P.

Broche, L. M.

Kennedy, B. W.

Lurie, D. J.

MacEachern, C.

Osteoarthritis and Cartilage

English

L.M. Broche

B.W. Kennedy

C. MacEachern

G.P. Ashcroft

D.J. Lurie

Crossref

Fast field-cycling NMR of cartilage: a way toward molecular imaging

Aberdeen University Research

Proteins differentially expressed in OA SF identiﬁed with gretare than 2 foldchange and P<0.05Protein Anova(p)Maximumfold changeHighest meanconditionS100-A10 0.00028 2.2 OACD109 antigen 0.00039 2.0 OAPhospholipid transfer proteinisoform 10.00098 2.7 OAComplement component C8gamma chain0.0115 3.1 OACollagen alpha-1(I) chain 0.0459 2.8 OACalsyntenin-1 0.0485 2.1 OAIntegral membrane protein 2B 0.00068 2.1 Normalmannan-binding lectin serineprotease 20.0061 2.2 NormalKeratin, type II cytoskeletal 7 0.0114 2.2 NormalCyclin D binding myb-liketranscription factor 10.0240 6.2 NormalAbstracts / Osteoarthritis and Cartilage 22 (2014) S57–S489S66101SERUM BIOCHEMICAL MARKERS OF JOINT METABOLISM ANDINFLAMMATION IN RELATION TO CLINICAL SYMPTOMS ANDPHYSICAL FUNCTION IN ADULTS WITH SYMPTOMATIC KNEEOSTEOARTHRITISA.E. Connelly, A.J. Tucker, L.S. Kott, A.M. Duncan, A.J. Wright. Univ. ofGuelph, Guelph, ON, CanadaPurpose: To date, the majority of osteoarthritis (OA) biomarkerresearch has examined associations between biomarker levels andradiographic parameters. While radiography provides information onthe structural burden of disease, it is insensitive to small changes incartilage metabolism and does not always correlate with the mostsigniﬁcant clinical expression in OA, pain. The purpose of this study wasto investigate the associations between joint metabolism and inﬂam-mation with pain and physical function in adults with painful knee OA.This is in support of qualifying burden of disease biomarkers withclinical variables to support the study, management, and understandingof disease pathology in OA.Methods: The study used baseline data from 54 adults with knee OAparticipating in a nutrition intervention study. The 100 mm visualanalogue scale version of theWestern Ontario andMcMaster UniversityOsteoarthritis Index (WOMAC) was used to assess pain, stiffness, andphysical disability. A minimumWOMAC pain score of 125 was used as acutoff for participant inclusion. Physical functionwas assessed with a 6-minute walk test (:6MWT) and stair climb task (SCT). Serum concen-trations of biomarkers included measures of cartilage degradation(cartilage oligomeric matrix protein [COMP]), cartilage synthesis (type-IIA collagen N-propeptide [PIIANP]), synovial metabolism (hyaluronicacid [HA]), cartilage degrading enzyme levels (matrix metal-loproteinase 3 [MMP-3]), and inﬂammation (C-reactive protein [CRP]).COMP, PIIANP, HA, and MMP-3 were measured by enzyme-linkedimmunosorbent assay and CRP was measured by an immunoturbidi-metric assay. Correlations between biomarkers and clinical variableswere assessed using Spearman correlation coefﬁcients.Results: Participants (38 females and 16 males) had a mean age of 60 11.9 years, BMI of 32.6  7.5 kg/m2, disease duration of 86.6  112.2months, and WOMAC pain score of 193.4  94.04 mm. Higher serumMMP-3 levels were signiﬁcantly associated with higher WOMAC painscores (R ¼ 0.27, p ¼ 0.05), controlling for age and body mass index(BMI). Higher levels of serum HA were signiﬁcantly associated withdecreased walking distance in the :6MWT (R ¼ -0.35, p ¼ 0.01) andlonger time taken in the SCT (R ¼ 0.31, p ¼ 0.02), when controlling forage and BMI. Higher CRP levels were signiﬁcantly associated withhigher WOMAC physical disability score (R ¼ 0.34, p ¼ 0.01) and worseperformance in the :6MWT (R¼ -0.38, p¼ 0.005) and SCT (R¼ 0.44, p¼0.001) when age was controlled for, but these associations were notsigniﬁcant when BMI was controlled for. COMP and PIIANP were notsigniﬁcantly associated with any clinical variables analyzed.Conclusion: SerumMMP-3 levels were associated with pain and serumHA levels were associated with physical functioning in adults whosuffer from mild to moderate pain and impaired physical functioningfrom knee OA. Previous studies have shown that HA and MMP-3 arerelated to structural knee parameters in OA. Therefore, results from thisstudy demonstrate that serum HA and MMP-3 also have potential asqualiﬁed burden of disease biomarkers that are clinically meaningful.(Research supported by the Ontario Ministry of Agriculture, Food andRural Affairs, project #200121).102FAST FIELD-CYCLING NMR OF CARTILAGE: A WAY TOWARDMOLECULAR IMAGINGL.M. Broche, B.W. Kennedy, C. MacEachern, G.P. Ashcroft, D.J. Lurie.Univ. of Aberdeen, Aberdeen, United KingdomPurpose: A previous pilot study (presented at OARSI 2012) showed thatFast Field-Cycling NMR (FFC NMR) can be used to characterise thedispersion curves of cartilage in the region 0.4 to 3 MHz proton Larmorfrequency. One feature of these dispersion curves, quadrupolar peaks,arise from relatively well known interactions between water protonsand the 14N nuclei of certain immobilised proteins. We have also pre-viously shown that osteoarthritic cartilage gives rise to smaller quad-rupolar peaks than cartilage from healthy volunteers. However, theexact protein responsible for the quadrupolar peaks observed in carti-lage samples is uncertain. This present work aims to determine theprotein responsible for the quadrupolar peaks observed in cartilage andhow these signals correlate with disease progression.Methods: Cartilage samples from femoral heads and knee joints wereobtained after consenting patients undergoing joint replacement sur-gery or above-knee amputation at NHS Grampian Hospitals. All workwith human tissue was approved by the North of Scotland researchethic committee. First, a pilot study was conducted on a commercial FFCNMR scanner (Stelar s.r.l, Mede, Italy). We used a pulse sequence with ashort acquisition time (< 1 ms), and included 7 patients undergoingarthroplasty for osteoarthritis (OA) and 5 patients undergoing hemi-arthroplasty for hip fracture. The hip fracture group had no clinical orradiological evidence of OA prior to the fracture being sustained andthere was no macroscopic evidence of cartilage degeneration seenintra-operatively on femoral head inspection. In a second, larger study,we examined the cartilage from 50 patients with evidence of OAchanges and 50without using both long (w20ms) and short acquisitiontimes.We also measured the quadrupolar signals from a variety of samplesusing both long and short acquisition times including: normal andosteoarthritic human cartilage; collagen preparations using distilledwater and a commercially available porcine collagen sponge (Colla-tamp; Tribute pharamaceutical); glycosaminoglycan extracts fromhuman cartilage (both liquid and lyophilised); and human cartilagewhich had been extracted of its glycosaminoglycan (GAG) content with4M guanidinium chloride.Results: Variations of the quadrupolar signals were visible betweenshort (< 1ms) and long (CPMG echo trains, 20 ms) acquisitions. Longacquisitions did not show any contrast between normal and diseasedcartilagewhereas signiﬁcant differences in quadrupolar peak amplitudewere observed using short acquisition time sequences (3.6 s-1 vs 2.2 s-1,p < 0.01). We observed no quadrupolar peaks in glycosaminoglycanextracts from cartilage, whether liquid or lyophilised.Preparations containing 50%w/w collagen showed quadrupolar peaksindicating that collagen may be the source of this signal in cartilage.However, the quadrupolar peaks observed using short acquisition timeswere only seen in cartilage which had not been extracted of its GAGcontent. This suggests that the quadrupolar peaks observed in cartilageare likely to be linked to the macromolecular collagen ﬁbril networkand are reduced with decreasing matrix integrity. Interestingly, theshort-lived component of the FFC-NMR signal was not evident in GAG-extracted cartilage cores from healthy or diseased cartilage. However,the long-lived signal was unaffected and was not found to be correlatedwith OA changes.Conclusions: GAG extracts of cartilage samples and analysis of collagenpreparations have shown that GAGs are not likely to be the proteinsresponsible for quadrupolar peaks. The amide linkages on the backboneof collagen are therefore indicated as the source of quadrupolar peaksbut the organisation of the macromolecular collagen network withinthe cartilage matrix also seems to play an important role in the inter-action between collagen proteins and water protons.When this matrix is disturbed, such as after GAG-extraction, theamplitude of quadrupolar peaks are signiﬁcantly diminished and thereis a loss of the short-lived FFC NMR signal. Therefore it is likely that thequadrupolar signals of cartilage report on the macromolecularFigure 1. Odds ratio for Rapid Progression in ROA versus AsymptomaticCohorts after various adjustments to underlying variability in Asympto-matic cohort.Black (open) ¼ Thinning, Blue (closed) ¼ Thickening, Red(dashes) represents p ¼ 0.05 (approximately). square ¼ SD adjustmentequal for all regions, circle ¼ adjustments differ between central andexternal regions and remaining regions.Abstracts / Osteoarthritis and Cartilage 22 (2014) S57–S489 S67organisation of the collagen network within the cartilage. We are thuspreparing methods to image this signal in vivo using FFC MRI and zeroecho time acquisition techniques. We hope applications of this tech-nique will allow new ways to non-invasively detect and stage osteo-arthritic cartilage before morphological structural changes occur, as areappreciated with conventional MRI techniques.103RELEASED MACROPHAGE MARKERS AS PREDICTORS OF KNEE OAPROGRESSIONH.N. Daghestani y, C.F. Pieper z, V.B. Kraus y. yDuke Inst. of MolecularPhysiology, Durham, NC, USA; zDuke Univ. Med. Ctr., Durham, NC, USAPurpose: Despite being one of themost common types of arthritis and aleading cause of disability worldwide, Osteoarthritis (OA) often goesundiagnosed until its later stages and little beyond palliative therapy isavailable. Biomarkers are particularly needed that can be used forprognosis or to monitor the efﬁcacy of future therapeutics. There aremany unanswered questions regarding the complex nature of joint tis-sue biology, but the role of innate immunity in the pathology of OA hasbecomemore evident in recent years. Speciﬁcally, synovialmacrophage-produced cytokines drive aggrecanases, matrix metalloproteinases, andother destructive responses towards cartilage degradation. Moreover,the pattern of synovial ﬂuid (SF) cytokines in knee OA is indicative ofmacrophage-mediated inﬂammasome activation. In a recent study, weshowed that the quantity of folate receptor (FR-bþ) macrophages injoints based on etarfolatide imaging correlated with radiographic kneeOA. We also showed that sCD163 and sCD14, which are macrophagemarkers, correlated with inﬂammatory phenotypes and radiographicseverity of OA. The goal of this study was to evaluate the effectiveness ofusing the macrophage marker, sCD163, as a prognostic tool for knee OA.Methods: sCD163 was measured by ELISA in the synovial ﬂuid of 86subjects (128 knees) with knee OA from the Prediction of OsteoarthritisProgression (POP) cohort. The POP cohort provided baseline SF andserum samples and 3-year longitudinal follow-up to assess the pre-dictive capability of sCD163 for radiographic OA structural progressionbased on either osteophyte formation or joint space narrowing. Models,using generalized estimating equations (to account for correlationwithin knees), were ﬁtted with adjustment for age, gender, and bodymass index (BMI), to evaluate associations of sCD163 with OA pro-gression phenotypes. P values 0.05 were considered signiﬁcant.Results: Baselinesynovialﬂuid sCD163wasassociatedwithprogressionofkneeOA; speciﬁcally SF sCD163was associatedwith change in osteophyteseverity (p ¼ 0.0107), but not change in joint space narrowing. However,systemic sCD163 did not show any correlation with OA progression.Conclusions: Shedding of CD163 from macrophages typically occurs inresponse to oxidative stress mediators and other inﬂammatory stimuli.The association of SF sCD163 with knee OA progression supports thegrowing inference that inﬂammation plays an important role in theprogression of disease; this marker could prove useful for identifying ahigh-risk subgroup of knee OA patients. Furthermore, these resultscontribute to a growing literature identifying macrophages and mac-rophage-activation pathways as potential targets for new OA therapies.104DETECTING KNEE CARTILAGE THICKNESS CHANGE AT THREE ANDSIX MONTHSR. Buck y, M-P. Hellio Le Graverand z, M. Hudelmaier x,k, W. Wirth k,F. Eckstein x,k. y StatAnswers Consulting LLC, Minneapolis, MN, USA;z Pﬁzer Global Res. and Dev., New London, CT, USA; x Inst. of Anatomy,Paracelsus Med. Univ., Salzburg, Austria; k Chondrometrics GmbH,Ainring, GermanyPurpose: Previous work found large differences (> 10%/y and < -10%/y)in knee cartilage thickness in distinct subregions of the joint betweenannual visits and these were more frequent in osteoarthritis patientsthan in asymptomatic subjects. Given these large observed changes inas little as 12 months, it is likely that important changes in cartilagethickness may be detectable at even shorter intervals. The goal of thisstudy is to explore the magnitude of femorotibial cartilage thicknesschanges in participants with radiographic osteoarthritis (ROA) andasymptomatic subjects over three and six month observation periods.Data are available at 12 and 24month periods for the same subjects andmake it possible, for the ﬁrst time, to directly compare short, i.e., 3month, versus long-term, i.e., 24 month, changes. We also presentrobustness studies to assess the potential impact of observed, butstatistically insigniﬁcant, differences between ROA and asymptomaticknees in the measurement error of cartilage thickness change.Methods: CoronalMR images (3 Tesla) were acquired in 145women (71with ROA, 74 without symptoms or ROA) at baseline, 3, 6, 12 and 24months. Femorotibial cartilage thickness was determined for ﬁve tibialand three femoral subregions in each (medial/lateral) compartment ateach visit. Rapid change in knee cartilage in individual regions wasclassiﬁed via false discovery methods and the frequencies of rapidchange were compared between ROA and asymptomatic subjects.Ordered values of knee regional cartilage thickness change in ROA andasymptomatic cohorts were also compared. Differences between ROAand asymptomatic subjects in measurement error, as estimated fromscan/rescan analyses, were not statistically signiﬁcant, but standarddeviations were slightly higher (average of 10%) in ROA subjects. Toassess possible differences in variability between the ROA and asymp-tomatic knees, thickness change in asymptomatic subjects were nor-malized by a) increasing change values by up to 60% across all regions;or b) increasing change values by up to 60% in central and externalregions, while increasing change values in remaining regions by 5%.Results: Rapid cartilage thinning was found in 18.3% of ROA subjects atMonth 3 and this increased steadily over time with 25.4%, 33.8%, and40.8% at Months 6,12, and 24. These frequencies were higher (p-value<0.05) than observed in the asymptomatic cohort at all visits exceptMonth 3. In contrast, The percentage of subjects in the ROA cohort withrapid cartilage thickening was also statistically larger than frequenciesobserved in the asymptomatic cohort, but were 28.2%, 21.1% and 33.8%for Months 3, 6, and 12 and dropped to only 7% at Month 24 showing noapparent trend over time. Even after inﬂating asymptomatic change by15 to 45% the frequency of rapid progression was still signiﬁcantlyhigher in ROA cohort than in asymptomatic cohort, except at Month 3;see ﬁgure. While the largest percentage of subjects with rapid pro-gression (thinning or thickening) at a given visit was 59%, overall thepercentage of subjects with rapid progression at some visit was 81.7%.Also, although less than 8% of regions were classiﬁed as having rapidprogression they accounted for 34% (at Month 3) to 64% (at Month 24)of observed variation from zero in thickness change. Results fromordered values were similar, but not as robust to adjusting standarddeviation.Conclusions: Regions with rapid subregional (focal) progression are animportant component of cartilage thickness change in subjects withosteoarthritis. This study reafﬁrms the method used for classiﬁcation isreasonable for estimating rapid progression in an ROA cohort. Theresults show that rapid thinning and thickening is detectable at sixmonths and may also be present at three months.

Fast field-cycling NMR of cartilage : a way toward molecular imaging

Broche, L.M.

Kennedy, B.W.

Ashcroft, G.P.

Lurie, D.J.

Elsevier - Publisher Connector 

Fast field-cycling NMR of cartilage: a way toward molecular imaging 

Proteins differentially expressed in OA SF identiﬁed with gretare than 2 fold
change and P<0.05
Protein Anova
(p)
Maximum
fold change
Highest mean
condition
S100-A10 0.00028 2.2 OA
CD109 antigen 0.00039 2.0 OA
Phospholipid transfer protein
isoform 1
0.00098 2.7 OA
Complement component C8
gamma chain
0.0115 3.1 OA
Collagen alpha-1(I) chain 0.0459 2.8 OA
Calsyntenin-1 0.0485 2.1 OA
Integral membrane protein 2B 0.00068 2.1 Normal
mannan-binding lectin serine
protease 2
0.0061 2.2 Normal
Keratin, type II cytoskeletal 7 0.0114 2.2 Normal
Cyclin D binding myb-like
transcription factor 1
0.0240 6.2 Normal
Abstracts / Osteoarthritis and Cartilage 22 (2014) S57–S489S66101
SERUM BIOCHEMICAL MARKERS OF JOINT METABOLISM AND
INFLAMMATION IN RELATION TO CLINICAL SYMPTOMS AND
PHYSICAL FUNCTION IN ADULTS WITH SYMPTOMATIC KNEE
OSTEOARTHRITIS
A.E. Connelly, A.J. Tucker, L.S. Kott, A.M. Duncan, A.J. Wright. Univ. of
Guelph, Guelph, ON, Canada
Purpose: To date, the majority of osteoarthritis (OA) biomarker
research has examined associations between biomarker levels and
radiographic parameters. While radiography provides information on
the structural burden of disease, it is insensitive to small changes in
cartilage metabolism and does not always correlate with the most
signiﬁcant clinical expression in OA, pain. The purpose of this study was
to investigate the associations between joint metabolism and inﬂam-
mation with pain and physical function in adults with painful knee OA.
This is in support of qualifying burden of disease biomarkers with
clinical variables to support the study, management, and understanding
of disease pathology in OA.
Methods: The study used baseline data from 54 adults with knee OA
participating in a nutrition intervention study. The 100 mm visual
analogue scale version of theWestern Ontario andMcMaster University
Osteoarthritis Index (WOMAC) was used to assess pain, stiffness, and
physical disability. A minimumWOMAC pain score of 125 was used as a
cutoff for participant inclusion. Physical functionwas assessed with a 6-
minute walk test (:6MWT) and stair climb task (SCT). Serum concen-
trations of biomarkers included measures of cartilage degradation
(cartilage oligomeric matrix protein [COMP]), cartilage synthesis (type-
IIA collagen N-propeptide [PIIANP]), synovial metabolism (hyaluronic
acid [HA]), cartilage degrading enzyme levels (matrix metal-
loproteinase 3 [MMP-3]), and inﬂammation (C-reactive protein [CRP]).
COMP, PIIANP, HA, and MMP-3 were measured by enzyme-linked
immunosorbent assay and CRP was measured by an immunoturbidi-
metric assay. Correlations between biomarkers and clinical variables
were assessed using Spearman correlation coefﬁcients.
Results: Participants (38 females and 16 males) had a mean age of 60 
11.9 years, BMI of 32.6  7.5 kg/m2, disease duration of 86.6  112.2
months, and WOMAC pain score of 193.4  94.04 mm. Higher serum
MMP-3 levels were signiﬁcantly associated with higher WOMAC pain
scores (R ¼ 0.27, p ¼ 0.05), controlling for age and body mass index
(BMI). Higher levels of serum HA were signiﬁcantly associated with
decreased walking distance in the :6MWT (R ¼ -0.35, p ¼ 0.01) and
longer time taken in the SCT (R ¼ 0.31, p ¼ 0.02), when controlling for
age and BMI. Higher CRP levels were signiﬁcantly associated with
higher WOMAC physical disability score (R ¼ 0.34, p ¼ 0.01) and worse
performance in the :6MWT (R¼ -0.38, p¼ 0.005) and SCT (R¼ 0.44, p¼
0.001) when age was controlled for, but these associations were not
signiﬁcant when BMI was controlled for. COMP and PIIANP were not
signiﬁcantly associated with any clinical variables analyzed.
Conclusion: SerumMMP-3 levels were associated with pain and serum
HA levels were associated with physical functioning in adults who
suffer from mild to moderate pain and impaired physical functioning
from knee OA. Previous studies have shown that HA and MMP-3 are
related to structural knee parameters in OA. Therefore, results from thisstudy demonstrate that serum HA and MMP-3 also have potential as
qualiﬁed burden of disease biomarkers that are clinically meaningful.
(Research supported by the Ontario Ministry of Agriculture, Food and
Rural Affairs, project #200121).
102
FAST FIELD-CYCLING NMR OF CARTILAGE: A WAY TOWARD
MOLECULAR IMAGING
L.M. Broche, B.W. Kennedy, C. MacEachern, G.P. Ashcroft, D.J. Lurie.
Univ. of Aberdeen, Aberdeen, United Kingdom
Purpose: A previous pilot study (presented at OARSI 2012) showed that
Fast Field-Cycling NMR (FFC NMR) can be used to characterise the
dispersion curves of cartilage in the region 0.4 to 3 MHz proton Larmor
frequency. One feature of these dispersion curves, quadrupolar peaks,
arise from relatively well known interactions between water protons
and the 14N nuclei of certain immobilised proteins. We have also pre-
viously shown that osteoarthritic cartilage gives rise to smaller quad-
rupolar peaks than cartilage from healthy volunteers. However, the
exact protein responsible for the quadrupolar peaks observed in carti-
lage samples is uncertain. This present work aims to determine the
protein responsible for the quadrupolar peaks observed in cartilage and
how these signals correlate with disease progression.
Methods: Cartilage samples from femoral heads and knee joints were
obtained after consenting patients undergoing joint replacement sur-
gery or above-knee amputation at NHS Grampian Hospitals. All work
with human tissue was approved by the North of Scotland research
ethic committee. First, a pilot study was conducted on a commercial FFC
NMR scanner (Stelar s.r.l, Mede, Italy). We used a pulse sequence with a
short acquisition time (< 1 ms), and included 7 patients undergoing
arthroplasty for osteoarthritis (OA) and 5 patients undergoing hemi-
arthroplasty for hip fracture. The hip fracture group had no clinical or
radiological evidence of OA prior to the fracture being sustained and
there was no macroscopic evidence of cartilage degeneration seen
intra-operatively on femoral head inspection. In a second, larger study,
we examined the cartilage from 50 patients with evidence of OA
changes and 50without using both long (w20ms) and short acquisition
times.
We also measured the quadrupolar signals from a variety of samples
using both long and short acquisition times including: normal and
osteoarthritic human cartilage; collagen preparations using distilled
water and a commercially available porcine collagen sponge (Colla-
tamp; Tribute pharamaceutical); glycosaminoglycan extracts from
human cartilage (both liquid and lyophilised); and human cartilage
which had been extracted of its glycosaminoglycan (GAG) content with
4M guanidinium chloride.
Results: Variations of the quadrupolar signals were visible between
short (< 1ms) and long (CPMG echo trains, 20 ms) acquisitions. Long
acquisitions did not show any contrast between normal and diseased
cartilagewhereas signiﬁcant differences in quadrupolar peak amplitude
were observed using short acquisition time sequences (3.6 s-1 vs 2.2 s-1,
p < 0.01). We observed no quadrupolar peaks in glycosaminoglycan
extracts from cartilage, whether liquid or lyophilised.
Preparations containing 50%w/w collagen showed quadrupolar peaks
indicating that collagen may be the source of this signal in cartilage.
However, the quadrupolar peaks observed using short acquisition times
were only seen in cartilage which had not been extracted of its GAG
content. This suggests that the quadrupolar peaks observed in cartilage
are likely to be linked to the macromolecular collagen ﬁbril network
and are reduced with decreasing matrix integrity. Interestingly, the
short-lived component of the FFC-NMR signal was not evident in GAG-
extracted cartilage cores from healthy or diseased cartilage. However,
the long-lived signal was unaffected and was not found to be correlated
with OA changes.
Conclusions: GAG extracts of cartilage samples and analysis of collagen
preparations have shown that GAGs are not likely to be the proteins
responsible for quadrupolar peaks. The amide linkages on the backbone
of collagen are therefore indicated as the source of quadrupolar peaks
but the organisation of the macromolecular collagen network within
the cartilage matrix also seems to play an important role in the inter-
action between collagen proteins and water protons.
When this matrix is disturbed, such as after GAG-extraction, the
amplitude of quadrupolar peaks are signiﬁcantly diminished and there
is a loss of the short-lived FFC NMR signal. Therefore it is likely that the
quadrupolar signals of cartilage report on the macromolecular
Figure 1. Odds ratio for Rapid Progression in ROA versus Asymptomatic
Cohorts after various adjustments to underlying variability in Asympto-
matic cohort.Black (open) ¼ Thinning, Blue (closed) ¼ Thickening, Red
(dashes) represents p ¼ 0.05 (approximately). square ¼ SD adjustment
equal for all regions, circle ¼ adjustments differ between central and
external regions and remaining regions.
Abstracts / Osteoarthritis and Cartilage 22 (2014) S57–S489 S67organisation of the collagen network within the cartilage. We are thus
preparing methods to image this signal in vivo using FFC MRI and zero
echo time acquisition techniques. We hope applications of this tech-
nique will allow new ways to non-invasively detect and stage osteo-
arthritic cartilage before morphological structural changes occur, as are
appreciated with conventional MRI techniques.
103
RELEASED MACROPHAGE MARKERS AS PREDICTORS OF KNEE OA
PROGRESSION
H.N. Daghestani y, C.F. Pieper z, V.B. Kraus y. yDuke Inst. of Molecular
Physiology, Durham, NC, USA; zDuke Univ. Med. Ctr., Durham, NC, USA
Purpose: Despite being one of themost common types of arthritis and a
leading cause of disability worldwide, Osteoarthritis (OA) often goes
undiagnosed until its later stages and little beyond palliative therapy is
available. Biomarkers are particularly needed that can be used for
prognosis or to monitor the efﬁcacy of future therapeutics. There are
many unanswered questions regarding the complex nature of joint tis-
sue biology, but the role of innate immunity in the pathology of OA has
becomemore evident in recent years. Speciﬁcally, synovialmacrophage-
produced cytokines drive aggrecanases, matrix metalloproteinases, and
other destructive responses towards cartilage degradation. Moreover,
the pattern of synovial ﬂuid (SF) cytokines in knee OA is indicative of
macrophage-mediated inﬂammasome activation. In a recent study, we
showed that the quantity of folate receptor (FR-bþ) macrophages in
joints based on etarfolatide imaging correlated with radiographic knee
OA. We also showed that sCD163 and sCD14, which are macrophage
markers, correlated with inﬂammatory phenotypes and radiographic
severity of OA. The goal of this study was to evaluate the effectiveness of
using the macrophage marker, sCD163, as a prognostic tool for knee OA.
Methods: sCD163 was measured by ELISA in the synovial ﬂuid of 86
subjects (128 knees) with knee OA from the Prediction of Osteoarthritis
Progression (POP) cohort. The POP cohort provided baseline SF and
serum samples and 3-year longitudinal follow-up to assess the pre-
dictive capability of sCD163 for radiographic OA structural progression
based on either osteophyte formation or joint space narrowing. Models,
using generalized estimating equations (to account for correlation
within knees), were ﬁtted with adjustment for age, gender, and body
mass index (BMI), to evaluate associations of sCD163 with OA pro-
gression phenotypes. P values 0.05 were considered signiﬁcant.
Results: Baselinesynovialﬂuid sCD163wasassociatedwithprogressionof
kneeOA; speciﬁcally SF sCD163was associatedwith change in osteophyte
severity (p ¼ 0.0107), but not change in joint space narrowing. However,
systemic sCD163 did not show any correlation with OA progression.
Conclusions: Shedding of CD163 from macrophages typically occurs in
response to oxidative stress mediators and other inﬂammatory stimuli.
The association of SF sCD163 with knee OA progression supports the
growing inference that inﬂammation plays an important role in the
progression of disease; this marker could prove useful for identifying a
high-risk subgroup of knee OA patients. Furthermore, these results
contribute to a growing literature identifying macrophages and mac-
rophage-activation pathways as potential targets for new OA therapies.
104
DETECTING KNEE CARTILAGE THICKNESS CHANGE AT THREE AND
SIX MONTHS
R. Buck y, M-P. Hellio Le Graverand z, M. Hudelmaier x,k, W. Wirth k,
F. Eckstein x,k. y StatAnswers Consulting LLC, Minneapolis, MN, USA;
z Pﬁzer Global Res. and Dev., New London, CT, USA; x Inst. of Anatomy,
Paracelsus Med. Univ., Salzburg, Austria; k Chondrometrics GmbH,
Ainring, Germany
Purpose: Previous work found large differences (> 10%/y and < -10%/y)
in knee cartilage thickness in distinct subregions of the joint between
annual visits and these were more frequent in osteoarthritis patients
than in asymptomatic subjects. Given these large observed changes in
as little as 12 months, it is likely that important changes in cartilage
thickness may be detectable at even shorter intervals. The goal of this
study is to explore the magnitude of femorotibial cartilage thickness
changes in participants with radiographic osteoarthritis (ROA) and
asymptomatic subjects over three and six month observation periods.
Data are available at 12 and 24month periods for the same subjects and
make it possible, for the ﬁrst time, to directly compare short, i.e., 3month, versus long-term, i.e., 24 month, changes. We also present
robustness studies to assess the potential impact of observed, but
statistically insigniﬁcant, differences between ROA and asymptomatic
knees in the measurement error of cartilage thickness change.
Methods: CoronalMR images (3 Tesla) were acquired in 145women (71
with ROA, 74 without symptoms or ROA) at baseline, 3, 6, 12 and 24
months. Femorotibial cartilage thickness was determined for ﬁve tibial
and three femoral subregions in each (medial/lateral) compartment at
each visit. Rapid change in knee cartilage in individual regions was
classiﬁed via false discovery methods and the frequencies of rapid
change were compared between ROA and asymptomatic subjects.
Ordered values of knee regional cartilage thickness change in ROA and
asymptomatic cohorts were also compared. Differences between ROA
and asymptomatic subjects in measurement error, as estimated from
scan/rescan analyses, were not statistically signiﬁcant, but standard
deviations were slightly higher (average of 10%) in ROA subjects. To
assess possible differences in variability between the ROA and asymp-
tomatic knees, thickness change in asymptomatic subjects were nor-
malized by a) increasing change values by up to 60% across all regions;
or b) increasing change values by up to 60% in central and external
regions, while increasing change values in remaining regions by 5%.
Results: Rapid cartilage thinning was found in 18.3% of ROA subjects at
Month 3 and this increased steadily over time with 25.4%, 33.8%, and
40.8% at Months 6,12, and 24. These frequencies were higher (p-value<
0.05) than observed in the asymptomatic cohort at all visits except
Month 3. In contrast, The percentage of subjects in the ROA cohort with
rapid cartilage thickening was also statistically larger than frequencies
observed in the asymptomatic cohort, but were 28.2%, 21.1% and 33.8%
for Months 3, 6, and 12 and dropped to only 7% at Month 24 showing no
apparent trend over time. Even after inﬂating asymptomatic change by
15 to 45% the frequency of rapid progression was still signiﬁcantly
higher in ROA cohort than in asymptomatic cohort, except at Month 3;
see ﬁgure. While the largest percentage of subjects with rapid pro-
gression (thinning or thickening) at a given visit was 59%, overall the
percentage of subjects with rapid progression at some visit was 81.7%.
Also, although less than 8% of regions were classiﬁed as having rapid
progression they accounted for 34% (at Month 3) to 64% (at Month 24)
of observed variation from zero in thickness change. Results from
ordered values were similar, but not as robust to adjusting standard
deviation.
Conclusions: Regions with rapid subregional (focal) progression are an
important component of cartilage thickness change in subjects with
osteoarthritis. This study reafﬁrms the method used for classiﬁcation is
reasonable for estimating rapid progression in an ROA cohort. The
results show that rapid thinning and thickening is detectable at six
months and may also be present at three months.


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Fast field-cycling NMR of cartilage : a way toward molecular imaging

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