S60 Poster Presentations from the knee joints, we found an increase in collagen type II degradation of 230% (p=0.07) on day 7, 300% (p=0.04) on day 14, and 240% (p=0.04) on day 28 in ACLT-operated knee joints compared to sham-operated knee joints (see figure). Conclusions: In a relative small sample size we demonstrated that collagen type II degradation fragments extracted from joints provide a useful surrogate marker for evaluating the disease status of the entire joint. This approach may save essential time in research models, compared to that of traditional histology techniques, and provides information for the entire joint com- pared to that of smaller regions of interests normally assessed by histopathology. As collagen type II degradation fragments are generated by MMPs, this approach may provide information on pathologically MMP activity in the joint. We propose that this technique may be used in various OA models and mouse genetic phenotypes to assess joint disease status, and thereby provide important information on pathology and efficacy of various po- tential treatments for OA. P89 PHARMACODYNAMIC MODULATION OF BONE-DERIVED AND CARTILAGE-DERIVED COLLAGEN BIOMARKERS IN THE OVARIECTOMIZED RAT MODEL P.G. Mitchell , M.G. Chambers, M.A. Carozza, C. Lin, H.W. Cole, J.L. Oskins, M. Schreiweis, N.H. Kulkarni, M.J. Berna, C.A. Schmalz, B.L. Ackermann, K.L. Duffin, J.E. Hale, J.E. Onyia Eli Lilly, Indianapolis, IN Purpose: To understand how estrogen [E2] treatment, cathepsin K [cat K] inhibition or matrix metalloproteinase [MMP] inhibition, modulate markers of type I and type II collagen turnover in the rat ovariectomy (ovx) model. Methods: Six month old, skeletally mature female Sprague Daw- ley rats were subject to ovx (n=48) or sham (n=8) surgery. Two days later ("baseline"), the ovariectomized animals were random- ized into the following groups (n=8/group except for ovx/vehicle: n=16): Sham/vehicle, Ovx/vehicle, Ovx/E2 (17-α-estradiol @ 0.1 mg/kg po qd), Ovx/cat K inhibitor (CRA-013783 @ 50 mg/kg po bid), Ovx/cat K inhibitor (CRA-013783 @ 50 mg/kg po bid dos- ing: week 2 - week 4 only), Ovx/MMP inhibitor (RS-130830 @ 50 mg/kg bid po). Urine (overnight) and plasma were collected from each animal at study termination (4 weeks). Urine CTX-II (uCTX-II: competition ELISA), plasma CTX-II (pCTX-II: sandwich ELISA) and urine CTX-I (uCTX-I: competition ELISA) were all assayed according to the manufacturers (Nordic Biosciences) in- structions. Urine NET2C (uNET2C) was measured in-house via immunoaffinity mass spectrometry. The data for each biomarker were first Box-Cox transformed in order to comply with standard statistical assumptions. Comparisons of means were performed on the transformed data using Dunnett’s test to determine groups statistically different from the ovx/vehicle group. Significance was set at P<0.05. Type II collagen protein expression in femora from 6 month intact female rats was determined via both western and mass spectral analysis of bone extracts (metaphysis and diaphysis). Type II collagen mRNA was determined via TaqMan analysis of mRNA extracted from similar bone samples. Results: In comparison to sham-operated animals, ovx in- duced significant increases in the concentrations of all colla- gen biomarkers measured in the study. uCTX-I concentration was not affected by administration of the MMP inhibitor, but was significantly reduced by E2 treatment and both cat K in- hibitor dosing regimes. uCTX-II levels were significantly reduced in each compound treated group. In contrast, although pCTX-II was significantly decreased by estradiol treatment, it was not lowered by the MMP inhibitor. pCTX-II levels were actually ele- vated in both groups treated with the cat K inhibitor compared to the ovx/vehicle group. uNET2C concentration was reduced by E2 treatment but slightly increased in the cat K treated animals. The MMP inhibitor reduced uNET2C levels; however, this did not reach statistical significance. Correlations between pCTX-II and uCTX-II (r=0.01), uNET2C and uCTX-I (r=0.18), and between uNET2C and uCTX-II (r=0.03) were uniformly absent. In contrast, uCTX-II and uCTX-I were highly correlated (r=0.84) while pCTX-II and uNET2C also exhib- ited reasonable correlation (r=0.52). Type II collagen expression was confirmed at both the mRNA and protein levels in samples of mature rat bone. Conclusions: The poor correlation between uCTX-II and pCTX- II implies that the two assays are measuring different molecular species that are produced and/or processed via different mech- anisms. In contrast, the high correlation between uCTX-I and uCTX-II suggests that the production of these two collagen epi- topes is mechanistically linked. The expression of type II collagen in bone, plus the pharmacodynamic profiles of pCTX-II, uCTX-II and uCTX-I suggest that in the rat ovx model, uCTX-II is pri- marily bone derived whereas pCTX-II is cartilage-derived. These data support the use of selective estrogen receptor modulators for reducing cartilage as well as bone loss in estrogen deficient states (e.g. menopause). P90 CARTILAGE BIOMARKER ANALYSIS OF YOUNG AND OLD ADULT FEMALE INTACT AND OVARIECTOMIZED CYNOMOLGUS MACAQUES S. Kumar , L.C. Dare, J.A. Vasko-Moser, G. Vaden, C.A. Capriotti, G.B. Stroup, S.J. Hoffman GlaxoSmithKline, Collegeville, PA Purpose: Osteoarthritis (OA) is known to occur naturally in both the rhesus and cynomolgus macaque and develops anywhere between 5 to 15 years of age. The structural, chemical and biochemical changes seen in monkeys with OA closely resemble the features of OA in humans. There is a great need to identify and develop biomarkers for OA. The purpose of this study was to evaluate the effect of age on the cartilage biomarkers of young and old cynomolgus macaques. In addition, we have also evaluated the effects of ovariectomy on these biomarkers. Methods: Two sets of monkeys were used; the first with a mean age of 4.2 years (SEM ± 0.3 years) and the second group with a mean age of 10.9 years (SEM ± 0.5 years). The cartilage degradation markers, serum and urinary C-telopeptide of colla- gen type II (CTxII) and serum Cartilage Oligomeric Matrix Protein (COMP) as well as the serum cartilage formation markers, ag- grecan chondroitin sulfate 846 epitope (CS846) and Procollagen II C-Propeptide (CPII) were evaluated in both groups of monkeys prior to and following medical ovariectomy (OVX). Blood was collected three times (separated by at least two weeks) prior to induction of OVX. Medical OVX was induced with monthly injec- tions of the GnRH agonist, Lupron, and additional blood draws were taken for biomarker analysis. Parameters for the groups were compared using the Student’s ttest with significance set at p ≤ 0.05. Results: Prior to medical ovariectomy, urinary and serum CTxII levels were 16- and 17-fold higher, respectively, in the young versus older monkeys (42.2 to 2.7 ng/mg of creatinine, respec- tively for urine and 63.7 and 3.7 pg/ml for serum). COMP levels were also significantly higher in younger monkeys than the older group (3.1 vs. 2.1 U/L) whereas serum CS846 levels were not different between the two age groups. CPII levels, however, were significantly higher in the older than younger monkeys (745 vs. 605 ng/mL). Biomarkers were also evaluated following medical ovariectomy using Lupron. Urinary CTxII levels were significantly elevated by