Teriparatide ameliorates articular cartilage degradation and aberrant subchondral bone remodeling in DMM mice

Objective

Knee osteoarthritis (KOA) is a highly prevalent musculoskeletal disorder characterized by degeneration of cartilage and abnormal remodeling of subchondral bone (SCB). Teriparatide (PTH (1-34)) is an effective anabolic drug for osteoporosis (OP) and regulates osteoprotegerin (OPG)/receptor activator of nuclear factor ligand (RANKL)/RANK signaling, which also has a therapeutic effect on KOA by ameliorating cartilage degradation and inhibiting aberrant remodeling of SCB. However, the mechanisms of PTH (1-34) in treating KOA are still uncertain and remain to be explored. Therefore, we compared the effect of PTH (1-34) on the post-traumatic KOA mouse model to explore the potential therapeutic effect and mechanisms.

Methods

In vivo study, eight-week-old male mice including wild-type (WT) (n ​= ​54) and OPG^-/- (n ​= ​54) were investigated and compared. Post-traumatic KOA model was created by destabilization of medial meniscus (DMM). WT mice were randomly assigned into three groups: the sham group (WT-sham; n ​= ​18), the DMM group (WT-DMM; n ​= ​18), and the PTH (1-34)-treated group (WT-DMM ​+ ​PTH (1-34); n ​= ​18). Similarly, the OPG^-/- mice were randomly allocated into three groups as well. The designed mice were executed at the 4th, 8th, and 12th weeks to evaluate KOA progression. To further explore the chondro-protective of PTH (1-34), the ATDC5 chondrocytes were stimulated with different concentrations of PTH (1-34) in vitro.

Results

Compared with the WT-sham mice, significant wear of cartilage in terms of reduced cartilage thickness and glycosaminoglycan (GAG) loss was detected in the WT-DMM mice. PTH (1-34) exhibited cartilage-protective by alleviating wear, retaining the thickness and GAG contents. Moreover, the deterioration of the SCB was alleviated and the expression of PTH1R/OPG/RANKL/RANK were found to increase after PTH (1-34) treatment. Among the OPG^-/- mice, the cartilage of the DMM mice displayed typical KOA change with higher OARSI score and thinner cartilage. The damage of the cartilage was alleviated but the abnormal remodeling of SCB didn't show any response to the PTH (1-34) treatment. Compared with the WT-DMM mice, the OPG^-/--DMM mice caught more aggressive KOA with thinner cartilage, sever cartilage damage, and more abnormal remodeling of SCB. Moreover, both the damaged cartilage from the WT-DMM mice and the OPG^-/--DMM mice were alleviated but only the deterioration of SCB in WT-DMM mice was alleviated after the administration of PTH (1-34). In vitro study, PTH (1-34) could promote the viability of chondrocytes, enhance the synthesis of extracellular matrix (ECM) (AGC, COLII, and SOX9) at the mRNA and protein level, but inhibit the secretion of inflammatory cytokines (TNF-α and IL-6).

Conclusion

Both wear of the cartilage was alleviated and aberrant remodeling of the SCB was inhibited in the WT mice, but only the cartilage-protective effect was observed in the OPG^-/- mice. PTH (1-34) exhibited chondro-protective effect by decelerating cartilage degeneration in vivo as well as by promoting the proliferation and enhancing ECM synthesis of chondrocytes in vitro. The current investigation implied that the rescue of the disturbed SCB is dependent on the regulation of OPG while the chondro-protective effect is independent of modulation of OPG, which provides proof for the treatment of KOA.

The translational potential of this article

Systemic administration of PTH (1-34) could exert a therapeutic effect on both cartilage and SCB in different mechanisms to alleviate KOA progression, which might be a novel therapy for KOA.

New bone-like tissue formation in calcific tendinopathy: A case report

Currently, the pathogenesis of nontraumatic heterotopic ossification (HO), e.g., bone-like tissue in calcific tendinopathy remains unclear. Here, we report a 75-year-old, right-handed Japanese woman who had been on hemodialysis for 3 years and was admitted to our hospital to evaluate pain and swelling of the right forearm. She worked as a cook, and her main job over the 3 most recent years had been the frequent and continuous shredding of cabbage. A radiograph showed the highly radiopaque material on the dorsal aspect of the right wrist and in the right shoulder. The biopsy of this radiopaque material revealed HO with marrow, as well as calcified material. Histomorphometric analysis of the HO identified a severe type of osteitis fibrosa with a fibrous tissue volume to total volume of 19.8% (>0.5% required for diagnosis) and an osteoid volume to bone volume of 20.0% (>15% required for diagnosis). We found more woven bone-like tissue than lamellar bone-like tissue. However, the intact parathyroid hormone level was 3-times the normal upper limit with 203 pg/mL, but histomorphometric analysis of the right iliac crest revealed normal bone structure. These findings indicate that the frequent and continuous shredding action with the right hand contributed to the nontraumatic HO localized on the dorsal aspect of the right wrist.

Molecular mechanisms of osteogenesis and antibacterial activity of Cu-bearing Ti alloy in a bone defect model with infection in vivo

OBJECTIVE

The antibacterial activity of copper (Cu)-alloy biomaterials has shown a great potential in clinical application. Here, we evaluated the osteogenesis and antibacterial effects of Ti6Al4V-6.5wt%Cu alloy in an in vivo model of infected bone defects and determine their responsible proteins and pathways using proteomics.

METHODS

After bone defects were filled with Ti6Al4V and Ti6Al4V-6.5wt%Cu implants for 6 week, the tissue and bone samples around the implants were harvested for radiographic, micro-CT, histological, and bone-related gene expression analyses. An iTRAQ-based protein identification/quantification approach was used to analyze the osteogenic and antibacterial effects of Ti6Al4V-6.5wt%Cu alloy.

RESULTS

Imaging and histological results showed Ti6Al4V alloy induced a stronger inflammatory response than Ti6Al4V-6.5wt%Cu alloy; imaging results and osteogenic protein levels showed Ti6Al4V-6.5wt%Cu alloy exerted a stronger osteogenic effect. In vitro experiment, we found the Ti6Al4V-6.5wt%Cu had significant antibacterial effects and inhibited the activity of Staphylococcus aureus in the early stage. In addition, the bacterial biofilm formed in Ti6Al4V-6.5wt%Cu group was significantly lower than that in Ti6Al4V group. Proteomic screening of 4279 proteins resulted in 35 differentially expressed proteins for further examination which were mainly associated with the cellular process, metabolic process, stimulus response, and cellular component organization. In further exploration of the mechanism of osteogenic mineralization of Ti6Al4V-6.5wt%Cu alloy, we found out SDC4 and AGRN were the top two target proteins associated with osteogenic differentiation and bone mineralization.

CONCLUSION

Ti6Al4V-6.5wt%Cu alloy shows a great potential as a bone implant material due to its positive effects against bacterial infection and on bone formation.

THE TRANSLATIONAL POTENTIAL OF THIS ARTICLE

At present, titanium alloys and other non-antibacterial metal materials are used in orthopedic internal fixation operations. Our study demonstrates that Ti6Al4V-6.5wt%Cu alloy has good antibacterial and osteogenic effects in vivo and in vitro. This means that Ti6Al4V-6.5wt%Cu alloy may become a new kind of antimicrobial metallic material as internal fixation material to continuously exert its antimicrobial effects and reduce the infection rate after clinical internal fixation.

Evaluation of La(XT), a novel lanthanide compound, in an OVX rat model of osteoporosis

Purpose

The purpose of this study was to evaluate the efficacy and toxicity of a novel lanthanum compound, La(XT), in an ovariectomized (OVX) rat model of osteoporosis.

Methods

Twenty-four ovariectomized female Sprague Dawley rats were divided into 3 groups receiving a research diet with/without treatment compounds (alendronate: 3 mg/kg; La(XT) 100 mg/kg) for three months. At the time of sacrifice, the kidney, liver, brain, lung and spleen were collected for histological examination. The trabecular bone structure of the tibiae was evaluated using micro-CT and a three-point metaphyseal mechanical test was used to evaluate bone failure load and stiffness.

Results

No significant differences were noted in plasma levels of calcium, phosphorus, creatinine, alanine aminotransferase (ALT), and aspartate aminotransferase (AST) between the La(XT) treatment compared to the non-treated OVX group. Alendronate-treated animals (positive control) showed higher BV/TV, Tb.N and lower Tb.Th and Tb.Sp when compared to the non-treated OVX group. Mechanical analysis indicated that stiffness was higher in the alendronate (32.88%, p = 0.04) when compared to the non-treated OVX group. Failure load did not differ among the groups.

Conclusions

No kidney or liver toxicities of La(XT) treatments were found during the three-month study. The absence of liver and kidney toxicity with drug treatment for 3 months, as well as the increased trabecular bone stiffness are encouraging for the pursuit of further studies with La(XT) for a longer duration of time.

Kinsenoside attenuates osteoarthritis by repolarizing macrophages through inactivating NF-κB/MAPK signaling and protecting chondrocytes

The objective was to investigate the effect of kinsenoside (Kin) treatments on macrophage polarity and evaluate the resulting protection of chondrocytes to attenuate osteoarthritis (OA) progression. RAW264.7 macrophages were polarized to M1/M2 subtypes then administered with different concentrations of Kin. The polarization transitions were evaluated with quantitative real-time polymerase chain reaction (qRT-PCR), confocal observation and flow cytometry analysis. The mechanism of Kin repolarizing M1 macrophages was evaluated by Western blot. Further, macrophage conditioned medium (CM) and IL-1β were administered to chondrocytes. Micro-CT scanning and histological observations were conducted in vivo on anterior cruciate ligament transection (ACLT) mice with or without Kin treatment. We found that Kin repolarized M1 macrophages to the M2 phenotype. Mechanistically, Kin inhibited the phosphorylation of IκBα, which further reduced the downstream phosphorylation of P65 in nuclear factor-κB (NF-κB) signaling. Moreover, Kin inhibited mitogen-activated protein kinases (MAPK) signaling molecules p-JNK, p-ERK and p-P38. Additionally, Kin attenuated macrophage CM and IL-1β-induced chondrocyte damage. In vivo, Kin reduced the infiltration of M1 macrophages, promoted M2 macrophages in the synovium, inhibited subchondral bone destruction and reduced articular cartilage damage induced by ACLT. All the results indicated that Kin is an effective therapeutic candidate for OA treatment.

Aging-associated microstructural deterioration of vertebra in zebrafish

Zebrafish, a small teleost fish, is currently emerging as an animal model of local and systemic aging. In this study, we assessed age-related degenerative changes in the vertebral bone of zebrafish (3–12 month-post-fertilisation [mpf]) using micro-CT scanning. The bone volume (BV) of the trabecular bone in the male and female fish peaked at 6 mpf and reduced with age. In contrast to BV, bone mineral density and tissue volume did not change after 6 mpf, implying that the total mineral volume in the trabecular area remains unchanged, retaining the strength of vertebra. In addition, we performed micro-structural analysis of the trabecular thickness, trabecular number, and star volume of the tissue space and trabeculae, and found that the size of the trabecular bone reduced with age. Furthermore, aged zebrafish (45 mpf) exhibited ectopic ossification inside or outside of their vertebrae.

In summary, we analysed bone structural parameters in adult zebrafish vertebra, which are also used in humans, and demonstrated that aged zebrafish have deteriorated microarchitecture (trabecular thickness and number, tissue space star volume and trabecular star volume) with reduction of trabecular bones, similar to that observed during aging in humans. Zebrafish can be utilised as an animal model to understand the pathology of human bone aging, and the discovery of new therapeutic agents against age-related osteoporosis.

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We analysed bone structural parameters in adult zebrafish vertebrae.

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Microstructural changes in aged-zebrafish are similar to those in humans.

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Aged zebrafish exhibited ectopic ossification inside or outside of their vertebrae.

Bone structure is largely unchanged in growing male CD-1 mice fed lower levels of vitamin D and calcium than in the AIN-93G diet

Background

Calcium (Ca) and vitamin D (vit D) in the AIN-93G diet may be higher than required for healthy bone development, and mask the potential benefit of a dietary intervention.

Objective

The objective was to determine if lower levels of Ca and vit D than is present in the AIN-93G diet supports bone development in growing male CD-1 mice.

Methods

Weanling male CD-1 mice were randomized to modified AIN-93G diets containing either 100 (Trial 1) or 400 (Trial 2) IU vit D/kg diet within one of two or three Ca levels (0.35, 0.30, or 0.25% Ca diet in Trial 1 or 0.35% or 0.25% in Trial 2) or the AIN-93G diet (1000 IU/kg vit D and 0.5% Ca) from weaning to 4 months of age (n = 13–15/group). At 2 and 4 months of age, BMD and structural properties of the tibia were analyzed in vivo. Structure of lumbar vertebra 4 (L4) and mandible, and femur strength were assessed ex vivo at age 4 months.

Results

There were no differences in tibia, L4, and mandible structure between the AIN-93G diet and the 0.35% Ca groups at either vit D level. A few structure outcomes were compromised with the 0.25 and/or 0.3% Ca diets but there were no differences in femur biomechanical strength compared to AIN-93G group in either Trial.

Conclusion

At 400 or 100 IU vit D/kg diet, Ca can be lowered to 0.35% without detriment to BMD or bone structure while bone strength is not altered at lower Ca (0.25%) compared to CD-1 mice fed AIN-93G diet. Because of genetic variation in CD-1 mice among different breeding facilities, results in CD-1 mice from other facilities may differ from the present study.

High-fat/high-sucrose diet results in higher bone mass in aged rats

Intake of high-fat/high-sucrose (HFS) diet or high fat diet influences bone metabolism in young rodents, but its effects on bone properties of aged rodents still remain unclear. This study aimed to examine the effects of HFS diet intake on trabecular bone architecture (TBA) and cortical bone geometry (CBG) in aged rats. Fifteen male Wistar rats over 1 year were randomly divided into two groups. One group was fed a standard laboratory diet (SLD) and the other group was fed a HFS diet for six months. The femur/tibia, obtained from both groups at the end of experimental period, were scanned by micro-computed tomography for TBA/CBG analyses. Serum biochemical analyses were also conducted. Body weight was significantly higher in the HFS group than in the SLD group. In both femur and tibia, the HFS group showed higher trabecular/cortical bone mass in reference to bone mineral content, volume bone mineral density and TBA/CBG parameters compared with the SLD group. In addition, serum calcium, inorganic phosphorus, total protein, triacylglycerol, HDL and TRACP-5b levels were significantly higher in the HFS group than in the SLD group. There were good correlations between body weight and bone parameters in the femur and tibia. These results suggest that HFS diet intake results in higher bone mass in aged rats. Such effects of HFS diet intake might have been induced by increased body weight.

Soy protein improves tibial whole-bone and tissue-level biomechanical properties in ovariectomized and ovary-intact, low-fit female rats

BACKGROUND

Osteoporosis and related fractures, decreased physical activity, and metabolic dysfunction are serious health concerns for postmenopausal women. Soy protein might counter the negative effects of menopause on bone and metabolic health due to the additive or synergistic effects of its bioactive components.

OBJECTIVE

To evaluate the effects of ovariectomy (OVX) and a soy-protein diet (SOY) on bone outcomes in female, low-capacity running (LCR) rats selectively bred for low aerobic fitness as a model of menopause.

METHODS

At 27 weeks of age, LCR rats (N = 40) underwent OVX or sham (SHAM) surgery and were randomized to one of two isocaloric and isonitrogenous plant-protein-based dietary treatments: 1) soy-protein (SOY; soybean meal); or, 2) control (CON, corn-gluten meal), resulting in four treatment groups. During the 30-week dietary intervention, animals were provided ad libitum access to food and water; body weight and food intake were measured weekly. At completion of the 30-week intervention, body composition was measured using EchoMRI; animals were fasted overnight, euthanized, and blood and hindlimbs collected. Plasma markers of bone formation (osteocalcin, OC; N-terminal propeptide of type I procollagen, P1NP) and resorption (tartrate-resistant acid phosphatase, TRAP5b; C-terminal telopeptide of type I collagen, CTx) were measured using ELISA. Tibial trabecular microarchitecture and cortical geometry were evaluated using μCT; and torsional loading to failure was used to assess cortical biomechanical properties. Advanced glycation end-product (AGE) content of the femur was measured using a fluorimetric assay, and was expressed relative to collagen content measured by a colorimetric OH-proline assay. Two-factor ANOVA or ANOVCA was used to test for significant main and interactive effects of ovarian status (OV STAT: OVX vs. SHAM) and DIET (SOY vs. CON); final body weight was included as a covariate for body-weight-dependent cortical geometry and biomechanical properties.

RESULTS

OVX had significantly greater CTx than SHAM; SOY did not affect bone turnover markers. OVX adversely affected trabecular microarchitecture as evidenced by reduced BV/TV, trabecular thickness (Tb.Th), trabecular number (Tb.N), and connectivity density (Conn.D), and by increased trabecular separation (Tb.Sp) and structural model index (SMI). SOY increased BV/TV only in ovary-intact animals. There was no effect of OVX or SOY on tibial cortical geometry. In SHAM and OVX rats, SOY significantly improved whole-bone strength and stiffness; SOY also increased tissue-level stiffness and tended to increase tissue-level strength (p = 0.067). There was no effect of OVX or SOY on AGE content.

CONCLUSION

Soy protein improved cortical bone biomechanical properties in female low-fit rats, regardless of ovarian hormone status.

Bone development in growing female mice fed calcium and vitamin D at lower levels than is present in the AIN-93G reference diet

Background

The AIN-93G reference (REF) diet is used to allow the comparison within and between studies of different research groups but its levels of vitamin D (vit D) and calcium (Ca) may be higher than required for healthy bone structure and bone mineral density (BMD).

Objective

To determine if lower dietary levels of Ca (3.5, 3 or 2.5 g Ca/kg diet) at 1 of 2 levels of vit D (100 or 400 IU/kg diet) supports similar development of bone structure and BMD compared to AIN-93G reference (REF) diet in female CD-1 mice at 2 and 4 months of age.

Methods

Within a trial, weanling female mice (n = 12–15/group) were randomized to 1 of 4 diets until necropsy at 4 months of age: Trial 1: 100 IU vit D/kg + 3.5, 3 or 2.5 g Ca/kg diet or 1000 IU vit D/kg + 5 g Ca/kg diet (REF); and Trial 2: 400 IU vit D/kg + 3.5, 3 or 2.5 g Ca/kg diet or 1000 IU vit D/kg + 5 g/kg diet (REF). At age 2 and 4 months, in vivo bone structure and BMD were assessed using micro-computed tomography (μCT) at the proximal and midpoint tibia. At age 4 months, lumbar vertebra 4 (L4) and mandible structure were analyzed ex vivo, femur strength at midpoint and neck was assessed and serum 25(OH)D₃ and PTH were quantified.

Results

For Trial 1 (100 IU vit D/kg), there were no differences in tibia structure at age 2 and 4 months nor L4 or mandible structure or femur strength at the midpoint or neck at 4 months of age despite lower serum 25(OH)D₃ among all groups compared to REF. For Trial 2 (400 IU vit D/kg), mice fed 2.5 g Ca/kg diet had lower (p < 0.05) Ct.Ar/Tt.Ar and Ct.Th at the tibia midpoint compared to REF. Furthermore, Ct.Th. was greater in REF and 3.5 g Ca/kg diet compared to 2.5 g Ca/kg diet at age 2 but not 4 months of age. At L4, BV/TV was lower (p < 0.05) in the 3 g Ca/kg diet group compared to REF at age 4 months. There were no differences among groups for serum 25(OH)D₃ or femur strength at the midpoint or neck. Serum PTH was not elevated compared to REF in either Trial.

Conclusion

Lowering both dietary vit D (100 IU/kg) and Ca (2.5 g/kg) in AIN-93G diet did not result in differences in bone development of female CD-1 mice at early adulthood. Translational relevance of bone studies conducted using the AIN-93G diet may be affected by its high vit D and Ca content.

Methionine restriction alters bone morphology and affects osteoblast differentiation

Methionine restriction (MR) extends the lifespan of a wide variety of species, including rodents, drosophila, nematodes, and yeasts. MR has also been demonstrated to affect the overall growth of mice and rats. The objective of this study was to evaluate the effect of MR on bone structure in young and aged male and female C57BL/6J mice. This study indicated that MR affected the growth rates of males and young females, but not aged females. MR reduced volumetric bone mass density (vBMD) and bone mineral content (BMC), while bone microarchitecture parameters were decreased in males and young females, but not in aged females compared to control-fed (CF) mice. However, when adjusted for bodyweight, the effect of MR in reducing vBMD, BMC and microarchitecture measurements was either attenuated or reversed suggesting that the smaller bones in MR mice is appropriate for its body size. In addition, CF and MR mice had similar intrinsic strength properties as measured by nanoindentation. Plasma biomarkers suggested that the low bone mass in MR mice could be due to increased collagen degradation, which may be influenced by leptin, IGF-1, adiponectin and FGF21 hormone levels. Mouse preosteoblast cell line cultured under low sulfur amino acid growth media attenuated gene expression levels of Col1al, Runx2, Bglap, Alpl and Spp1 suggesting delayed collagen formation and bone differentiation. Collectively, our studies revealed that MR altered bone morphology which could be mediated by delays in osteoblast differentiation.

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MR affected the growth rates of males and young females, but not aged females.

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CF and MR mice had similar intrinsic strength properties.

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Low methionine media attenuated bone differentiation genes in MC3T3-E1 preosteoblast cells.

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The lower bone mass in MR mice is appropriate for its smaller body size.