Effects of 16-month treatment with the cathepsin K inhibitor ONO-5334 on bone markers, mineral density, strength and histomorphometry in ovariectomized cynomolgus monkeys

Beyond resorption: osteoclasts as drivers of bone formation

Emerging evidence illustrates that osteoclasts (OCs) play diverse roles beyond bone resorption, contributing significantly to bone formation and regeneration. Despite this, OCs remain mysterious cells, with aspects of their lifespan-from origin, fusion, alterations in cellular characteristics, to functions-remaining incompletely understood. Recent studies have identified that embryonic osteoclastogenesis is primarily driven by osteoclast precursors (OCPs) derived from erythromyeloid progenitors (EMPs). These precursor cells subsequently fuse into OCs essential for normal bone development and repair. Postnatally, hematopoietic stem cells (HSCs) become the primary source of OCs, gradually replacing EMP-derived OCs and assuming functional roles in adulthood. The absence of OCs during bone development results in bone structure malformation, including abnormal bone marrow cavity formation and shorter long bones. Additionally, OCs are reported to have intimate interactions with blood vessels, influencing bone formation and repair through angiogenesis regulation. Upon biomaterial implantation, activation of the innate immune system ensues immediately. OCs, originating from macrophages, closely interact with the immune system. Furthermore, evidence from material-induced bone formation events suggests that OCs are pivotal in these de novo bone formation processes. Nevertheless, achieving a pure OC culture remains challenging, and interpreting OC functions in vivo faces difficulties due to the presence of other multinucleated cells around bone-forming biomaterials. We here describe the fusion characteristics of OCPs and summarize reliable markers and morphological changes in OCs during their fusion process, providing guidance for researchers in identifying OCs both in vitro and in vivo. This review focuses on OC formation, characterization, and the roles of OCs beyond resorption in various bone pathophysiological processes. Finally, therapeutic strategies targeting OCs are discussed.

Abeliophyllum distichum Nakai alleviates postmenopausal osteoporosis in ovariectomized rats and prevents RANKL-induced osteoclastogenesis in vitro

ETHNOPHARMACOLOGICAL RELEVANCE

Abeliophyllum distichum Nakai (AD), called Miseon, is one of Korea's monotypic endemic species. As a folk remedy, the AD has been used to treat inflammatory disease, stomachaches, diarrhea, and gynecologic disease in Korea. Some researchers have reported that the AD has anti-cancer, anti-inflammatory, and anti-oxidant effects. But the protective effect of AD leaf for osteoporosis has not been reported yet.

AIM OF THE STUDY

This study aimed to analyze the effects and mechanism of AD-ethyl acetate fraction (EA) extract on the osteoporosis, one of the gynecologic disease.

MATERIALS AND METHODS

The RAW 264.7 cells were used as a model for RANKL-induced osteoclastogenesis. We measured the TRAcP activity, expressions of NFATc1, c-fos, and MAPK to investigate the effect of AD-EA. OVX-induced osteoporosis rat model was used as menopausal osteoporosis. After both ovaries were removed through a surgical procedure, and AD-EA or 17b-estradiol was orally administered for 8 weeks. BMD of femurs was measured as well as the bone morphometric parameter, such as BV/TV, trabecular thickness, number and surface using a micro CT.

RESULTS

AD-EA significantly inhibited TRAcP activity, actin ring formation, pit formation and the expressions of osteoclast-related genes in a dose-dependent manner through the inhibition of the MAPK and c-fos/NFATc1 pathway. In addition, low dose administration of AD-EA improved the deterioration of trabecular bone microarchitecture caused by OVX through the inhibition of bone resorption by TRAcP and CTK.

CONCLUSIONS

These results suggest that AD-EA may contribute to the therapy of osteoporosis caused by menopause in women.

Cortical bone mineral density is increased by the cathepsin K inhibitor ONO-5334, which leads to a robust increase in bone strength: results from a 16-month study in ovariectomised cynomolgus monkeys

This study evaluated the long-term effects of the cathepsin K inhibitor ONO-5334 on bone mass and strength in ovariectomised (OVX) cynomolgus monkeys. Animals were assigned to one of the following six groups: Sham (non-OVX), OVX control treated with vehicle, ONO-5334 1.2, 6 or 30 mg/kg/day, p.o., or alendronate (ALN) 0.05 mg/kg/2 weeks, i.v. for 16 months. Peripheral quantitative computed tomography (pQCT) analysis revealed that ONO-5334 increased not only trabecular bone mineral density (BMD) but also cortical BMD in the distal radius and the lumbar vertebra. ONO-5334 and ALN suppressed the deterioration of trabecular architecture by micro-CT analysis in the distal radius. Assessments of bone strength showed that ONO-5334 increased maximum load at the distal and midshaft radius. The linear regression lines between bone mass and strength in the lumbar vertebra were tended to be shifted towards increasing bone strength in the ONO-5334 6 and 30 mg/kg groups compared with the ALN groups. This indicated that bone strength was higher in the ONO-5334 groups than the ALN group, even though bone mineral content (BMC) and BMD were comparable. Subpopulation analysis revealed that, at similar integral BMC or BMD level, cortical bone mass for ONO-5334 was higher than for ALN; the opposite effects were observed for trabecular bone. In conclusion, ONO-5334 preferentially increased cortical bone, which may provide a greater contribution to bone strength. Since these results support a different mode of action for ONO-5334 compared with that of ALN, ONO-5334 may offer new therapeutic options to patients with osteoporosis.

Effects of the Cathepsin K Inhibitor ONO-5334 and Concomitant Use of ONO-5334 with Methotrexate on Collagen-Induced Arthritis in Cynomolgus Monkeys

We examined whether the cathepsin K inhibitor, ONO-5334, administered alone or in combination with methotrexate (MTX), could ameliorate joint destruction evoked by collagen-induced arthritis (CIA) in female cynomolgus monkeys. CIA was induced by immunizing with bovine type II collagen. ONO-5334 (30 mg/kg/day) was orally administered once daily and MTX (10 mg/body/day) twice weekly for 9 weeks. X-ray (evaluation of joint destruction) and swelling (inflammatory) scores of proximal interphalangeal (PIP), distal interphalangeal (DIP), and metacarpophalangeal (MP) joints were evaluated. Urinary concentrations of C-terminal telopeptide of type I collagen (CTX-I) and type II collagen (CTX-II) were measured. Arthritis, accompanied by bone and cartilage destruction, was successfully induced in this collagen-induced arthritis monkey model. ONO-5334 showed no suppressive effect on joint swelling, while the joint swelling scores in the MTX and combination (ONO-5334 + MTX) groups were less than 50% compared with the control group. ONO-5334 decreased X-ray score by a mean of 64% (p<0.05 vs the control group), and MTX also decreased in X-ray score by a mean of 46% but with no statistical significance. Combination of ONO-5334 and MTX further decreased the X-ray score by 28% over MTX group (74% reduction vs the control group, p<0.01). Maximum increase in CTX-I (10-fold) and CTX-II (7-fold) compared to baseline was observed at 7 and 3 weeks after the first sensitization, respectively. After treatment with ONO-5334 alone or in combination with MTX, concentrations were maintained near baseline for both markers. In conclusion, ONO-5334 prevented joint destruction but not joint inflammation in this monkey CIA model. Concomitant use of ONO-5334 with MTX reduced architectural joint destruction compared to MTX alone; therefore, ONO-5334 may help to prevent joint destruction in combination with MTX for the treatment of rheumatoid arthritis.

Effect of a cathepsin K inhibitor on arthritis and bone mineral density in ovariectomized rats with collagen-induced arthritis

Objectives

Cathepsin K is expressed by osteoclasts and synovial fibroblasts and degrades key components of bone and cartilage. Inhibition of cathepsin K protease activity may be beneficial for the prevention of bone erosion and cartilage degradation in rheumatoid arthritis (RA). The collagen-induced arthritis (CIA) rat model is well established for studying the pathology and treatment of RA. We investigated the effect of ONO-KK1-300-01, a cathepsin K inhibitor (CKI), on arthritis and bone mineral density (BMD) in rats with CIA.

Methods

Seven-month-old female Sprague Dawley rats were divided into 5 groups: rats without CIA (CNT); CIA rats that underwent ovariectomy (OVX) and were treated with CKI; CIA rats that underwent OVX and were treated with vehicle (Veh); CIA rats that underwent sham surgery and were treated with CKI; and CIA rats that underwent sham surgery and were treated with Veh. CKI was orally administered at a dose of 15 mg/kg, thus initiating collagen sensitization, until death at 4 weeks. We evaluated hind paw thickness and the arthritis score every week until death. Radiographs of the resected left foot were obtained with a soft X-ray apparatus. Destruction of bone and cartilage was classified and scored as previously described by Engelhardt et al. BMD was measured by bone densitometry at the halfway point between the distal metaphysis and the diaphysis of the resected right femur. We also performed histomorphometry of the proximal left tibia, histological evaluation of arthritis, and a bone strength test.

Results

CKI administration significantly reduced hind paw thickness and the arthritis score, and prevented a decrease in BMD. The radiographic score was significantly lower in the CKI group than in the Veh group. In the histomorphometric analysis, bone-resorption parameters were significantly lower in the CKI groups than in the Veh groups. CKI significantly inhibited synovial proliferation in the CIA rats. In the bone strength test, the ultimate stress was significantly higher in the CKI groups than in the Veh groups.

Conclusion

Our findings indicate that cathepsin K inhibitors may inhibit systemic and local bone loss, ameliorate arthritis, and attenuate the decrease of bone strength in an animal model of arthritis.

Antiresorptive effect of a cathepsin K inhibitor ONO-5334 and its relationship to BMD increase in a phase II trial for postmenopausal osteoporosis

Background

ONO-5334 is a cathepsin K inhibitor that induced bone mineral density (BMD) gain in a phase II study in postmenopausal osteoporosis patients. Even though the antiresorptive effect could only be monitored in the morning during the study, simulation can allow the antiresorptive effect to be assessed over 24 h, with assessment of the relationship to BMD gain.

Methods

Inhibition of the serum C-telopeptide of type I collagen (sCTX) level at doses of ONO-5334 of 100 mg once daily (QD), 300 mg QD, and 50 mg twice daily (BID) was simulated using plasma ONO-5334 pharmacokinetic (PK) data for repeated dose administration in a phase I study and corresponding sCTX inhibition from the PK-pharmacodynamic (PK/PD) relationship. sCTX was selected because it has a high signal-to-noise ratio compared to other telopeptides. A negative sigmoidal shape for the PK/PD relationship between plasma ONO-5334 and sCTX levels was obtained in our previous study.

Results

The simulated sCTX inhibition reached >99% of the maximal inhibitory effect (Emax) at 0.5 h in all treatment groups, and decreased to <80% Emax at 8 and 12 h at 50 mg BID and 100 mg QD, respectively. However, sCTX inhibition at 300 mg QD was maintained at ≥82% Emax over 24 h. The mean sCTX inhibition rates for 24 h at 100 mg QD, 300 mg QD and 50 mg BID were 63, 95 and 80% Emax, respectively. There was a positive linear relationship by treatment group between mean sCTX inhibition over 24 h and observed BMD gain in the phase II study.

Conclusion

The dose response for BMD with ONO-5334 at 100 and 300 mg QD and higher BMD gain at 50 mg BID vs. 100 mg QD can be explained by sCTX inhibition over 24 h. The simulation gave the antiresorptive effect of ONO-5334 over 24 h and allowed prediction of BMD gain due to ONO-5334.

Trial registration

The registration number in The European Union Clinical Trials Register is 2007–002417-39. The date of registration was August 31, 2007.

Electronic supplementary material

The online version of this article (doi:10.1186/s12891-017-1625-y) contains supplementary material, which is available to authorized users.

Beneficial Effects and Toxicity Studies of Xian-ling-gu-bao on Bone Metabolism in Ovariectomized Rats

Xian-ling-gu-bao (XLGB) is a well-known patented traditional Chinese prescription widely used to treat osteoporosis, osteoarthritis, aseptic bone necrosis, or climacteric syndrome. However, recent reports have suggested that XLGB may cause liver injury in humans. In the present study, we aimed to evaluate the efficacy of XLGB in the prevention of osteoporosis in the zebrafish and ovariectomized (OVX) rats, both of which have been used as osteoporosis models. The safety of XLGB after long-term administration to OVX rats was also assessed. OVX rats were administered by oral gavage 270 mg/kg (recommended daily dose), 1350 mg/kg, and 1800 mg/kg of XLGB for 26 weeks. Bone mineral density, relative bone surface to bone volume, relative bone volume to total volume, trabecular number, mean trabecular thickness, and mean trabecular spacing in OVX rats were examined at the end of the 26-week dosing period. Additionally, OPG and RANKL expression in the femur were determined by western blot and immunohistochemical staining. To evaluate the safety of XLGB, body weight, hematology, serum biochemistry markers related to toxicology, and organ histopathology were determined in each group of OVX rats. Conversely, the zebrafish was treated with prednisolone to induce osteoporosis in the embryo. Disodium etidronate was used as a treatment control. XLGB was shown to be effective in preventing osteoporosis in both the OVX rats and the prednisolone-treated zebrafish. Similarly, XLGB increased OPG protein and decreased RANKL protein in OVX rats. Interestingly, no obvious toxicity was observed in the heart, liver, kidney, small intestine, or stomach at dosages of up to 1800 mg/kg after treating the OVX rats for 26 weeks. XLGB was shown to be very effective in treating osteoporosis in OVX rats. No obvious toxicity or adverse effects developed in OVX rats at dosages up to 1800 mg/kg, which is equivalent to six times the daily-recommended dose. Therefore, XLGB should be considered a good option for the treatment of post-menopausal osteoporosis.

Effects of long term treatment with high doses of odanacatib on bone mass, bone strength, and remodeling/modeling in newly ovariectomized monkeys

The objectives here were to evaluate the effects of odanacatib (ODN) at doses exceeding the clinical exposure on biomechanical properties of lumbar vertebrae (LV), hip and central femur (CF), and compare ODN to alendronate (ALN) on bone remodeling/modeling in ovariectomized (OVX) monkeys. Ten days post-surgery, animals were treated with vehicle (VEH), ODN-L (2mg/kg/day, p.o.), ODN-H (8/4mg/kg/day), or ALN (30μg/kg/week, s.c.) for 20months. An intact group was also included. ODN-L provided systemic exposures of 1.8-fold of clinical exposure. ODN-H started at 20-fold for 5.5months, and then reduced to 7.8-fold of clinical exposure, compared to ALN at approximated clinical exposure. From cross sectional analyses, LV density and peak load in ODN at both doses or ALN were not different from VEH or Intact. However, cortical thickness of femoral neck (FN) and CF in ODN were higher (21-34%, p<0.05) than VEH, due to smaller endocortical (Ec) perimeter of FN (10-11%; p<0.05) and CF (9-12%; ODN-L, p<0.05), and larger CF periosteal (Ps) perimeter (2-12%; ODN-H, p<0.001) versus VEH. ODN groups also showed slightly higher cortical porosity and Ps non-lamellar bone in CF. ODN-H treatment resulted in higher CF peak load (p<0.05) versus VEH. For all bone sites analyzed, a positive, linear relationship (r(2)=0.46-0.69, p<0.0001) of peak load to density or structural parameters was demonstrated. No treatment-related differences in the derived intrinsic strength properties were evidenced as compared between groups. ALN reduced all remodeling surfaces without affecting Ps modeling. Trabecular and intracortical remodeling were reduced in ODN groups, similar to ALN. Ec mineralizing surface in ODN-H trended to be lower than VEH by month 20, but Ec bone formation indices in ODN groups generally were not different from VEH. Ps modeling in ODN groups was significantly higher than other treatment groups. This study overall demonstrated the bone safety profile of ODN and its unique mechanism on cortical bone supporting the clinical application for osteoporosis treatment.