Efficacy and safety of fixed doses of intranasal Esketamine as an add-on therapy to Oral antidepressants in Japanese patients with treatment-resistant depression: a phase 2b randomized clinical study.

BACKGROUND: Esketamine nasal spray (Spravato) in conjunction with oral antidepressants (ADs) is approved in the European Union, United States, and other markets for treatment-resistant depression (TRD). Efficacy, safety, and tolerability of esketamine nasal spray in Japanese patients with TRD needs to be assessed. METHODS: This Phase 2b, randomized, double-blind (DB), placebo-controlled study was conducted in adult Japanese patients with TRD meeting the Diagnostic and Statistical Manual of Mental Disorders (fifth edition) criteria of major depressive disorder with nonresponse to ≥ 1 but < 5 different ADs in the current episode at screening. Patients were treated with a new oral AD for 6 weeks (prospective lead-in phase); nonresponders were randomized (2:1:1:1) to placebo or esketamine (28-, 56-, or 84-mg) nasal spray along with the continued use of AD for 4 weeks (DB induction phase). Responders (≥50% reduction from baseline in the Montgomery-Asberg Depression Rating Scale [MADRS] total score) from the DB induction phase continued into the 24-week posttreatment phase and patients who relapsed could participate in a 4-week open-label (OL) second induction (flexibly-dosed esketamine). The primary efficacy endpoint, change from baseline in the MADRS total score at Day 28 in the DB induction phase, was based on mixed-effects model using repeated measures pairwise comparisons using a Dunnett adjustment. RESULTS: Of the 202 patients randomized in the DB induction phase (esketamine [n = 122] or placebo [n = 80]), the MADRS total scores decreased from baseline to Day 28 of the DB induction phase (- 15.2, - 14.5, - 15.1, and - 15.3 for esketamine 28 mg, 56 mg, 84 mg, and placebo groups, respectively), indicating an improvement in depressive symptoms; however, the difference between the esketamine and placebo groups was not statistically significant. The most common treatment-emergent adverse events during the DB induction phase in the combined esketamine group (incidences ranging from 12.3 to 41.0%) were blood pressure increased, dissociation, dizziness, somnolence, nausea, hypoaesthesia, vertigo, and headache; the incidence of each of these events was > 2-fold higher than the corresponding incidence in the placebo group. CONCLUSIONS: Efficacy of esketamine plus oral AD in Japanese TRD patients was not established; further investigation is warranted. All esketamine doses were safe and tolerated. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02918318 . Registered: 28 September 2016.

JunB plays a crucial role in development of regulatory T cells by promoting IL-2 signaling.

The AP-1 transcription factor JunB plays crucial roles in multiple biological processes, including placental formation and bone homeostasis. We recently reported that JunB is essential for development of Th17 cells, and thus Junb-deficient mice are resistant to experimental autoimmune encephalomyelitis. However, the role of JunB in CD4+ T cells under other inflammatory disease conditions is unknown. Here we show that mice lacking JunB in CD4+ T cells (Junbfl/flCd4-Cre mice) were more susceptible to dextran sulfate sodium (DSS)-induced colitis because of impaired development of regulatory T (Treg) cells. Production of interleukin (IL)-2 and expression of CD25, a high affinity IL-2 receptor component, were decreased in Junb-deficient CD4+ T cells in vitro and in vivo. Naive CD4+ T cells from Junbfl/flCd4-Cre mice failed to differentiate into Treg cells in the absence of exogenously added IL-2 in vitro. A mixed bone marrow transfer experiment revealed that defective Treg development of Junb-deficient CD4+ T cells was not rescued by co-transferred wild-type cells, indicating a significance of the cell-intrinsic defect. Injection of IL-2-anti-IL-2 antibody complexes induced expansion of Treg cells and alleviated DSS-induced colitis in Junbfl/flCd4-Cre mice. Thus JunB plays a crucial role in the development of Treg cells by facilitating IL-2 signaling.

Pharmacodynamics of atabecestat (JNJ-54861911), an oral BACE1 inhibitor in patients with early Alzheimer's disease: randomized, double-blind, placebo-controlled study.

BACKGROUND: ß-Secretase enzyme (BACE) inhibition has been proposed as a priority treatment mechanism for Alzheimer's disease (AD), but treatment initiation may need to be very early. We present proof of mechanism of atabecestat (also known as JNJ-54861911), an oral BACE inhibitor for the treatment of AD, in Caucasian and Japanese populations with early AD who do not show signs of dementia. METHODS: In two similarly designed phase I studies, a sample of amyloid-positive elderly patients comprising 45 Caucasian patients with early AD diagnosed as preclinical AD (n = 15, Clinical Dementia Rating [CDR] = 0) or with mild cognitive impairment due to AD (n = 30, CDR = 0.5) and 18 Japanese patients diagnosed as preclinical AD (CDR-J = 0) were randomized 1:1:1 to atabecestat 10 or 50 mg or placebo (n = 6-8/treatment) daily for 4 weeks. Safety, pharmacokinetics (PK), and pharmacodynamics (PD) (i.e., reduction of cerebrospinal fluid [CSF] amyloid beta 1-40 [Aß1-40] levels [primary endpoint] and effect on other AD biomarkers) of atabecestat were evaluated. RESULTS: In both populations, atabecestat was well tolerated and characterized by linear PK and high central nervous system penetrance of unbound drug. Atabecestat significantly reduced CSF Aß1-40 levels from baseline at day 28 in both the 10-mg (67-68%) and 50-mg (87-90%) dose groups compared with placebo. For Caucasians with early AD, the least squares mean differences (95% CI) were - 69.37 (- 72.25; - 61.50) and - 92.74 (- 100.08; - 85.39), and for Japanese with preclinical AD, they were - 62.48 (- 78.32; - 46.64) and - 80.81 (- 96.13; - 65.49), respectively. PK/PD model simulations confirmed that once-daily 10 mg and 50 mg atabecestat can attain 60-70% and 90% Aß1-40 reductions, respectively. The trend of the reduction was similar across the Aß1-37, Aß1-38, and Aß1-42 fragments in both atabecestat dose groups, consistent with Aß1-40. CSF amyloid precursor protein fragment (sAPPß) levels declined from baseline, regardless of patient population, whereas CSF sAPPα levels increased compared with placebo. There were no relevant changes in either CSF total tau or phosphorylated tau 181P over a 4-week treatment period. CONCLUSIONS: JNJ-54861911 at 10 and 50 mg daily doses after 4 weeks resulted in mean CSF Aß1-40 reductions of 67% and up to 90% in both Caucasian and Japanese patients with early stage AD, confirming results in healthy elderly adults. TRIAL REGISTRATION: ALZ1005: ClinicalTrials.gov, NCT01978548. Registered on 7 November 2013. ALZ1008: ClinicalTrials.gov, NCT02360657. Registered on 10 February 2015.

Effects of eldecalcitol on bone and skeletal muscles in glucocorticoid-treated rats.

Glucocorticoids cause secondary osteoporosis and myopathy, characterized by type II muscle fiber atrophy. We examined whether a new vitamin D3 analogue, eldecalcitol, could inhibit glucocorticoid-induced osteopenia or myopathy in rats, and also determined the effects of prednisolone (PSL) and/or eldecalcitol on muscle-related gene expression. Six-month-old female Wistar rats were randomized into four groups: PSL group (10 mg/kg PSL); E group (0.05 µg/kg eldecalcitol); PSL + E group; and control group. PSL, eldecalcitol, and vehicles were administered daily for 2 or 4 weeks. Right calf muscle strength, muscle fatigue, cross-sectional areas (CSAs) of left tibialis anterior muscle fibers, and bone mineral density (BMD) were measured following administration. Pax7, MyoD, and myogenin mRNA levels in gastrocnemius muscles were also determined. Muscle strength was significantly higher in the PSL + E group than in the PSL group (p < 0.05) after 4 weeks, but not after 2 weeks. No significant difference in muscle fatigue was seen between groups at 2 or 4 weeks. CSAs of type II muscle fibers were significantly larger in the E group and the PSL + E group than in the PSL group at 4 weeks (p = 0.0093, p = 0.0443, respectively). Eldecalcitol treatment for 4 weeks maintained the same BMD as the PSL + E group. After 2 weeks, but not 4 weeks, eldecalcitol treatment significantly increased Pax7 and myogenin mRNA expression in gastrocnemius muscle, and PSL also stimulated myogenin expression. Eldecalcitol appears to increase muscle volume and to protect against femur BMD loss in PSL-administered rats, and it may also stimulate myoblast differentiation into early myotubes.

Eldecalcitol improves mechanical strength of cortical bones by stimulating the periosteal bone formation in the senescence-accelerated SAM/P6 mice - a comparison with alfacalcidol.

Eldecalcitol (ELD), a 2ß-hydroxypropyloxy derivative of 1α,25(OH)2D3, is a potent inhibitor of bone resorption that has demonstrated a greater effect at reducing the risk of fracture in osteoporotic patients than alfacalcidol (ALF). In the present study, we used the senescence-accelerated mouse strain P6 (SAM/P6), which has low bone mass caused by osteoblast dysfunction, to evaluate the effect of ELD on cortical bone in comparison with ALF. Four-month-old SAM/P6 mice were given either ELD (0.025 or 0.05µg/kg) or ALF (0.2 or 0.4µg/kg) by oral gavage 5 times/week for 6 weeks. Both ELD and ALF increased serum calcium (Ca) in a dose-dependent manner. Serum Ca levels in the ELD 0.05µg/kg group were comparable to those of the ALF 0.2µg/kg group. ELD 0.05µg/kg significantly improved the bone biomechanical properties of the femur compared with the vehicle control group (p<0.001) and the ALF 0.2µg/kg group (p<0.05) evaluated by 3-point bending test. The cortical area of the mid-femur in the ELD 0.05µg/kg group but not the ALF 0.2µg/kg group was significantly higher than those of the vehicle control group (p<0.001). Bone histomorphometry revealed that in the femoral endocortical surface, the suppression of bone resorption parameters (N.Oc/BS) and bone formation parameters (MS/BS) by ELD (0.05µg/kg) was greater than that by ALF (0.2µg/kg). In contrast, in the femoral periosteal surface, ELD 0.05µg/kg significantly increased bone formation parameters (BFR/BS, MS/BS) compared with the vehicle control group (p<0.05, p<0.01, respectively), whereas ALF 0.2µg/kg did not alter these parameters. These results indicate that ELD improved the biomechanical properties of femoral cortical bone not only by inhibiting endocortical bone resorption but also by stimulating the periosteal bone formation in SAM/P6 mice. This article is part of a Special Issue entitled '16th Vitamin D Workshop'.

Combination treatment with eldecalcitol (ED-71) and raloxifene improves bone mechanical strength by suppressing bone turnover and increasing bone mineral density in ovariectomized rats.

The aim of this study was to investigate the effect of combination treatment with eldecalcitol (ELD) and raloxifene (RAL) on bone turnover, bone mineral density (BMD), and bone strength. Eight-month-old rats were ovariectomized (OVX) or sham operated, and divided into five groups (Sham, OVX+vehicle, OVX+RAL, OVX+ELD and OVX+ELD+RAL). ELD (7.5 ng/kg) and RAL (0.3mg/kg) were orally administered alone or in combination daily. Urinary deoxypyridinoline (DPD) levels were measured after 4, 8, and 12 weeks of treatment. After 12 weeks of treatment, BMD and mechanical properties of the lumbar spine and femur were assessed, and bone histomorphometry was performed. Urinary DPD levels in all the treatment groups were significantly decreased compared with the OVX+vehicle group. At 4 weeks of treatment, urinary DPD level of the combination group was significantly lower than that of either monotherapy group. The reduction in the BMD of the lumbar spine and femur by OVX was significantly prevented in all the treatment groups, and the BMD in the combination group was significantly higher than that in either monotherapy group. The ultimate load and work to failure of the fifth lumbar vertebra were significantly improved only by the combination treatment. The femoral midshaft ultimate load was significantly increased in the OVX+ELD group and the combination group, and the femoral midshaft work to failure was increased only in the combination group. Bone histomorphometric analysis using the third lumbar vertebra revealed that osteoblast surface (Ob.S/BS), osteoclast surface (Oc.S/BS) and osteoclast number (N.Oc/BS) significantly decreased in all treatment groups, and osteoid surface (OS/BS) and bone formation rate (BFR/BS) significantly decreased in the ELD-treated and combination groups. The values of Ob.S/BS and OS/BS in the combination group were lower than those in either of the monotherapy groups. The bone formation parameters in the combination group were not reduced to below levels of the sham-operated control, suggesting that the combination therapy with ELD and RAL may not cause oversuppression of bone turnover. These results indicated that the combination treatment with ELD and RAL might be a beneficial therapy with respect to their combined effects of enhancing the mechanical properties of trabecular and cortical bone by suppressing bone turnover and increasing BMD more than either monotherapy.

Combination therapy with eldecalcitol and alendronate has therapeutic advantages over monotherapy by improving bone strength.

Eldecalcitol (ED-71), a 2ß-hydroxypropyloxy derivative of 1α,25(OH)(2)D(3), inhibits bone resorption more potently than does alfacalcidol while maintaining osteoblastic function in an estrogen-deficient, high-turnover osteoporosis rat model. Alendronate (ALN) has been reported to increase bone mass by suppressing bone resorption mainly by inducing apoptosis of osteoclasts. The aim of this study was to clarify the combination effect of ED-71 and ALN on bone loss in ovariectomized rats. Wistar-Imamichi rats (32weeks old) were ovariectomized and randomly assigned to 10 groups (n=9-11); 11 rats were sham-operated. Rats were orally administered either vehicle alone, ALN (0.05, 0.2mg/kg), ED-71 (0.015, 0.03µg/kg), or a combination of ALN and ED-71. The treatment started 2weeks after surgery and continued for 12weeks. ED-71 significantly increased calcium and phosphorus in serum and urine; however, the mean values were within the normal range. Bone mineral density (BMD) and maximum load in both the lumbar spine and femur significantly increased with ED-71 monotherapy, and showed a tendency to increase with ALN monotherapy. Compared with ALN monotherapy, the combination of ALN and ED-71 significantly increased BMD and maximum load in both the lumbar spine and femur, suggesting that the combination therapy is more beneficial than ALN monotherapy in this protocol. The combination treatment had an additive suppressive effect on eroded surface and osteoclast number, with the suppressive effect more potent than either ALN or ED-71 monotherapy. Moreover, the combination therapy partially counteracted the suppressive effects of ALN on bone formation and on the histomorphometric indices of osteoblast number and activity. Interestingly, ALN had no effect on the anabolic action of ED-71. In conclusion, the combination therapy of ALN and ED-71 has therapeutic advantages over ALN monotherapy in terms of improving bone mechanical strength without excessive suppression of bone turnover.

[Diagnostic imaging of treatment in osteoporosis; new active vitamin D].

Active vitamin D drugs, such as alfacalcidol or calcitriol, have been on the market for about 30 years as a remedy for osteoporosis and are still the most popular drugs for osteoporosis in Japan. Eldecalcitol (EDR), a new active vitamin D compound, became the production sale approval in 2011. The results of the randomized, active comparator, double blind study to compare its anti-fracture efficacy with alfacalcidol (ALF) concluded that EDR has superior effect to ALF in preventing vertebral fractures in osteoporotic patients. Moreover, our longitudinal analysis of hip geometry by clinical CT in a subgroup has disclosed an unexpected potential of EDR to increase the cortical cross-sectional area and to maintain cortical thickness, probably through a more potent effect of EDR in mitigating endocortical bone resorption compared to ALF.

Effects of alfacalcidol on mechanical properties and collagen cross-links of the femoral diaphysis in glucocorticoid-treated rats.

Bone fragility is increased in glucocorticoid (GC)-induced osteopenia even though GC-treated patients have higher bone mineral density (BMD), suggesting that the impaired bone quality may affect bone strength. This study was conducted to clarify the effects of GC on bone strength and collagen cross-links of adult rats and the effect of coadministration of alfacalcidol (ALF), a prodrug of active vitamin D(3). Six-month-old male Wistar-Imamichi rats (n = 32) were divided into the following four groups with equal average body weight: (1) 4-week age-matched controls, (2) 4-week GC (prednisolone, 10 mg/kg daily, i.m.) with concomitant administration of vehicle, (3) 4-week GC with concomitant administration of ALF (0.05 µg/kg daily, p.o.), and (4) 4-week GC with concomitant administration of ALF (0.1 µg/kg daily, p.o.). At the end of treatment, BMD, collagen cross-links, mechanical properties of the femoral midshaft, bone metabolic markers, and biochemical parameters were analyzed. In the GC group, femoral bone strength decreased without any change of BMD. This was accompanied by a decrease in the content of enzymatic cross-links. ALF (0.1 µg/kg) inhibited the GC-induced reduction in bone strength. The content of mature cross-links in the 0.1-µg/kg ALF group was significantly higher than that in the GC group. GC treatment caused a decrease in bone metabolic markers and serum calcium levels, which was counteracted by ALF coadministration. Preventive treatment with ALF inhibited the deterioration of bone mechanical properties primarily in association with the restoration of enzymatic cross-link formation and amelioration of the adverse effects of GC treatment on calcium metabolism.

Comparison of effects of alfacalcidol and alendronate on mechanical properties and bone collagen cross-links of callus in the fracture repair rat model.

Both bone density and quality are important determinants of bone strength. Bone quality is prescribed by matrix characteristic including collagen cross-linking and bone structural characteristics and is important in reinforcement of bone strength. We investigated the effects of alfacalcidol (ALF), a prodrug of calcitriol, and alendronate (ALN), a bisphosphanate, on the mechanical properties and content of enzymatic cross-links in femoral bone using a fracture repair rat model. Forty 3-month-old female Wistar-Imamichi rats were randomized into 4 groups: SHAM (sham-operated+vehicle), OVX (ovariectomy+vehicle), ALF (ovariectomy+ALF, 0.1 microg/kg/d, p.o.) and ALN (ovariectomy+ALN, 10 microg/kg/d, s.c.). Treatment began immediately after SHAM or OVX surgery. Three weeks later, all animals underwent transverse osteotomies at the midshaft of the left femur. Treatment was continued and rats were sacrificed at 12 weeks post-fracture for evaluation by X-ray radiography, micro-CT, pQCT, biomechanical testing and bone histomorphometry. In the ALN group, no new cortical shell appeared and the callus diameter was significantly larger than in the OVX group (p<0.05). Stiffness of fractured callus in the ALF group, but not in the ALN group, was significantly higher than in the OVX group. Young's modulus in the ALN group was significantly decreased compared to the OVX group. Moreover, micro-CT analysis showed that ALN treatment increased the lowly mineralized bone in the callus by, resulting in the highest content of woven bone area and lowest content of lamellar bone. The total amount of enzymatic cross-links in both the ALF and ALN groups was significantly higher than in the OVX control group. Of particular interest, the Pyr-to-Dpyr ratio was significantly decreased by ALF administration, suggesting that ALF but not ALN normalized the enzymatic cross-link patterns in fractured bone to the control level. In conclusion, ALN and ALF treatment increased bone strength via the distinctive effect on bone mass and quality. ALN formed larger calluses and increased enzymatic cross-links despite delayed woven bone remodeling into lamellar bone, whereas ALF treatment induced lamellar bone formation coincided with increasing in the enzymatic cross-linking and normalizing the cross-link pattern in callus to native bone pattern.

The combination therapy with alfacalcidol and risedronate improves the mechanical property in lumbar spine by affecting the material properties in an ovariectomized rat model of osteoporosis.

BACKGROUND: We conducted the present study to investigate the therapeutic effects of a combination treatment of alfacalcidol (ALF) and risedronate (RIS) on the bone mechanical properties of bone and calcium (Ca) metabolism using an ovariectomized (OVX) rat model of osteoporosis. METHODS: Female Wistar rats were OVX- or sham-operated at 40 weeks of age. Twelve weeks post-surgery, rats were randomized into seven groups: 1) sham + vehicle, 2) OVX + vehicle, 3) OVX + ALF 0.025 microg/kg/day, 4) OVX + ALF 0.05 microg, 5) OVX + RIS 0.3 mg, 6) OVX + RIS 3.0 mg, 7) OVX + ALF 0.025 microg + RIS 0.3 mg. Each drug was administered orally five times a week for 12 weeks. After treatment, we evaluated the mechanical properties of the lumbar vertebra and femoral midshaft. In the lumbar vertebra, structural and material analyses were performed using micro-computed tomography (micro-CT) and microbeam X-ray diffraction (micro-XRD), respectively. Biochemical markers in serum and urine were also determined. RESULTS: (1) With respect to improvement in the mechanical strength of the lumbar spine and the femoral midshaft, the combination treatment of ALF and RIS at their sub-therapeutic doses was more effective than each administered as a monotherapy; (2) In the suppression of bone resorption and the amelioration of microstructural parameters, the effects of ALF and RIS were considered to be independent and additive; (3) The improvement of material properties, such as microstructural parameters and the biological apatite (Bap) c-axis orientation, contributed to the reinforcement of spinal strength; and (4) The combination treatment of ALF and RIS normalized urinary Ca excretion, suggesting that this treatment ameliorated the changes in Ca metabolism. CONCLUSION: These results demonstrate that the combination treatment of ALF and RIS at their sub-therapeutic doses can improve the mechanical properties of the spine as well as the femur and ameliorate changes in Ca metabolism in an animal model of osteoporosis, suggesting that the combination treatment of ALF and RIS has a therapeutic advantage over each monotherapy for the treatment of osteoporosis.

1-Alpha, 25-dihydroxy vitamin D3 inhibits osteoclastogenesis through IFN-beta-dependent NFATc1 suppression.

1-Alpha, 25-dihydroxy vitamin D(3) (1alpha,25(OH)(2)D(3)), an active form of vitamin D(3), plays a critical role in calcium and bone metabolism. Although 1alpha,25(OH)(2)D(3) has been used for osteoporosis therapy, the direct role of 1alpha,25(OH)(2)D(3) on human osteoclastogenesis has not been well characterized. Here we show that 1alpha,25(OH)(2)D(3) treatment significantly inhibited human osteoclast formation at the early stage of differentiation in a concentration-dependent manner. 1alpha,25(OH)(2)D(3) inhibited the expression of nuclear factor of activated T cells c1 (NFATc1, also referred as NFAT2), an essential transcription factor for osteoclast differentiation, and upregulated the expression of interferon-beta (IFN-beta), a strong inhibitor of osteoclastogenesis in osteoclast progenitors. Inhibitory effects of 1alpha,25(OH)(2)D(3) on osteoclastogenesis and NFATc1 expression were restored by treatment with an antibody against IFN-beta, suggesting that upregulation of IFN-beta by 1alpha,25(OH)(2)D(3) treatment results in inhibition of NFATc1 expression, in turn interfering with osteoclast formation. Thus, our study may provide a molecular basis for the treatment of human bone diseases by 1alpha,25(OH)(2)D(3) through regulation of the IFN-beta and NFATc1 axis.

Transgenic mice overexpressing macrophage migration inhibitory factor (MIF) exhibit high-turnover osteoporosis.

UNLABELLED: The bone phenotype of mice overexpressing MIF was studied. These mice showed decreased trabecular bone, increased bone formation rate, and increased MMP-3, -9, and -13 mRNA expression in the femora and tibias. This model provides evidence of the role played by MIF in bone remodeling and balance in vivo. INTRODUCTION: The role of macrophage migration inhibitory factor (MIF) in in vivo bone remodeling remains unelucidated. We describe disordered bone metabolism in transgenic mice overexpressing MIF. MATERIALS AND METHODS: For in vivo study, muCT, bone histomorphometry, blood and urine biochemical data, and gene expression of MIF transgenic (MIF Tg) mice and littermate wildtype (WT) mice were examined. For in vitro study, osteoclastogenesis in the co-culture of bone marrow cells and osteoblasts from MIF Tg and WT were assessed. RESULTS: muCT analyses revealed a significant reduction in the trabecular bone of distal femur in MIF Tg at 8-12 weeks of age. Histomorphometric analysis revealed increase in several measures of bone formation. Osteoclastogenesis was not influenced by the origin of bone marrow cells or osteoblasts. Urine level of deoxypyridinoline/creatinine and the mRNA levels of matrix metalloproteinase (MMP) -3, -9, and -13 in femurs were elevated in MIF Tg. CONCLUSIONS: Overexpression of MIF causes high-turnover osteoporosis in mice. The increased expression of MMPs in bone was suggested, at least in part, as one cause of this phenotype, because MMPs plays important roles for bone resorption without affecting the formation of osteoclasts. This model provides evidence of the role played by MIF in bone remodeling and balance.

Modulation of bone turnover by alfacalcidol and/or alendronate does not prevent glucocorticoid-induced osteoporosis in growing minipigs.

The study was performed to clarify the effects of active vitamin D (alfacalcidol) and/or alendronate (ALN) on bone tissue turnover in glucocorticoid (GC)-treated growing minipigs. Göttingen minipigs aged 8 months were divided into six groups (n = 5 each): group BC, killed for baseline control; group GC, injected subcutaneously with prednisolone (0.5 mg/kg body weight [BW] per day, 5 days/week for 24 weeks); group VC, treated with vehicle alone; group alf, treated with oral alfacalcidol at 0.1 microm/kg BW per day, 5 days/week; group ALN, treated with alendronate 1 mg/kg BW per day; and group alf* ALN, treated with both alf and ALN as above. Biochemical examinations dual-energy X-ray absorptiometry, micro-computed tomography, peripheral quantitative computed tomography, and histomorphometry were performed. In group GC, all bone chemical markers were lower than in group VC. GC treatment reduced the age-dependent augmentation of bone mass and structure by reducing the bone formation rate (BFR) and activation frequency (Ac.f) relative to VC in lumbar bone and femoral cortex. Trabecular and osteonal wall thickness values did not change by GC. Treatments with alf, ALN, and alf* ALN did not have substantial effects on bone mass or structure. Alf treatment maintained lumbar BFR and Ac.f, while ALN reduced osteoclasts. Femoral cortical Ac.f values were not affected by these treatments. GC caused reduced bone formation, leading to low tissue turnover and imbalance of bone formation and resorption. Modulation of bone tissue turnover by alfacalcidol and/or alendronate failed to maintain the growth-dependent increases in mass and structure in GC-treated young minipigs.

[Vitamin D and bone quality].

Active vitamin D analogs such as alfacalcidol have been shown to reduce fracture risk in clinical trials in spite of its moderate effects on bone mass. It has been reported that active vitamin D analogs may improve bone quality, by amelioration of bone microarchitecture, by specific effect on cortical bones, by acceleration of calcification, and by effect on nature of bone matrix proteins. The bone quality assessments that clarify the effect on bone mechanical properties will become important for the positioning of osteoporosis drugs.

Reductions in bone turnover, mineral, and structure associated with mechanical properties of lumbar vertebra and femur in glucocorticoid-treated growing minipigs.

The present study was designed to determine the effects of glucocorticoid (GC) on bone turnover, minerals, structure, and bone mechanical properties in minipigs. Six 8-month-old Göttingen minipigs were subcutaneously injected with prednisolone (PN, 0.5 mg/kg body wt (BW)/day, 5 days/week for 26 weeks (Group GC)), 6 were treated with vehicle alone (Group VC), and 4 were sacrificed at start of the study for baseline controls (Group BC). The increase in BW was similar in all groups. PN significantly reduced serum osteocalcin and urinary type-1 collagen N-telopeptide levels at 13 weeks and thereafter, compared with baseline and control, and also reduced serum bone specific alkaline phosphatase levels relative to baseline. At 26 weeks, the longitudinal axis of the lumbar bone and length of femur were smaller in Group GC than Group VC. The total cross-sectional area of femur, but not the lumbar bone, in Group GC was significantly different from Group VC. BMD of the femur, but not L2, measured by DXA, was lower in Group GC than in Groups BC and VC. The cortical shell structure measured by 2D-micro-CT deteriorated and age-dependent increases in trabecular bone structure 3D micro-CT were reduced by PN. PN also caused deterioration of the cortical structure of the mid-femur. In L2 and femur, PN significantly reduced the ultimate load and maximum absorption energy of the femur and L2 compared with Group VC. The structural modulus in Group GC was lower than in Group BC. Regression analyses revealed that bone minerals, bone structure, and chemical markers correlated with mechanical properties of L2 and mid-femur. Our results indicate that PN reduced systemic bone formation and resorption and suppressed the age-dependent increases in bone minerals, structure, and mechanical properties of L2 and mid-femur. Reduced bone turnover seemed to be associated with a reduction in mechanical properties. The growing minipig could be a suitable model of GCs-induced osteoporosis in humans.